JP2024126013A - Polyarylene sulfide resin composition and molded article - Google Patents

Abstract

To provide a polyarylene sulfide resin composition that ensures burr reduction, fluidity and continuous moldability during molding while maintaining high impact resistance.SOLUTION: A polyarylene sulfide resin composition includes 1-50 pts.wt. of (B) a thermoplastic elastomer relative to 100 pts.wt. of (A) a polyarylene sulfide. The (A) polyarylene sulfide features: a melt flow rate of 50 g/10 min or more and 300 g/10 min or less as measured in accordance with ASTM D 1238-70 at 315°C and 5000 g load; a cooling crystallization temperature of 200°C or more and 230°C or less as determined with a differential scanning calorimeter (DSC) at a cooling rate of 20°C/min; a carboxyl group-content of 30 μmol/g or more and 100 μmol/g or less; and a degree of dispersion of 6.0 or more and 15.0 or less represented by (weight average molecular weight/number average molecular weight).SELECTED DRAWING: None

Description

The present invention relates to a polyarylene sulfide resin composition that generates little flash during molding, has high fluidity, and is excellent in continuous moldability, and to a molded article. More specifically, the present invention relates to a molded article that is suitable for use in plumbing parts for water supply.

Polyarylene sulfide resin (hereinafter sometimes abbreviated as PAS resin) has properties suitable for use as an engineering plastic, such as excellent heat resistance, chemical resistance, electrical insulation, and moist heat resistance, and is used in a variety of electrical and electronic parts, machine parts, and automotive parts by injection molding or extrusion molding.

However, PAS resin has lower impact resistance than other engineering plastics such as nylon and polybutylene terephthalate, so for applications requiring impact resistance, a method of blending PAS resin with an olefin resin has long been considered.

For example, Patent Document 1 discloses a method of blending an ethylene-α-olefin copolymer, which has excellent impact resistance. However, because the solidification temperature of the ethylene-α-olefin copolymer is lower than that of PAS resin, there is a problem in that burrs tend to occur during molding.

There have been several studies on reducing burrs in PAS resins. For example, Patent Document 2 discloses a PAS resin composition that reduces burrs during injection molding by controlling the ratio of the amount of long-term relaxation components and the amount of short-term relaxation components related to the melt viscoelasticity of a polyarylene sulfide resin and further blending a specific alkoxysilane compound.

Patent Document 3 discloses a method for reducing burrs by adding a polyphenylene ether resin or a mixture of a polyphenylene ether resin and a polystyrene resin to a polyarylene sulfide resin.

JP 2000-198923 A Japanese Patent Application Publication No. 11-158280 JP 2002-284996 A

When blending an alkoxysilane compound with a PAS resin to produce a PAS resin composition, the method described in Patent Document 2 is insufficient in reducing burrs, and in addition, when melt-kneading in an extruder, the reaction between the PAS and the alkoxysilane compound is insufficient, so a relatively large amount of the alkoxysilane compound needs to be added. As a result, when molding the PAS resin composition, the fluidity decreases, and the injection pressure needs to be increased, resulting in problems such as decreased moldability and poor continuous moldability. In addition, the method described in Patent Document 3 is insufficient in reducing burrs, and in addition, there is a significant decrease in fluidity and mechanical properties, especially impact strength, making it unusable for applications requiring excellent impact strength, such as applications around water.

The objective of the present invention is to obtain a polyarylene sulfide resin composition that has excellent impact resistance, low burr generation during molding (low burr properties), and excellent fluidity and continuous moldability without significantly impairing the heat resistance that polyarylene sulfide resins inherently possess.

The present inventors have conducted extensive research to solve the above problems and have arrived at the present invention.
(1) A polyarylene sulfide resin composition comprising 100 parts by weight of (A) polyarylene sulfide and 1 to 50 parts by weight of (B) thermoplastic elastomer, wherein the polyarylene sulfide (A) has a melt flow rate of 50 g/10 min or more and 300 g/10 min or less as measured under conditions of 315° C. and a load of 5,000 g in accordance with ASTM D 1238-70, a crystallization temperature measured at a temperature drop rate of 20° C./min using a differential scanning calorimeter (DSC) of 200° C. or more and 230° C. or less, a carboxyl group content of 30 μmol/g or more and 100 μmol/g or less, and a polydispersity expressed as weight average molecular weight/number average molecular weight of 6.0 or more and 15.0 or less.
(2) The polyarylene sulfide resin composition according to (1) above, further comprising 0.05 to 5 parts by weight of (C) an organic silane coupling agent having at least one functional group selected from the group consisting of an epoxy group, an amino group, and an isocyanate group, per 100 parts by weight of the polyarylene sulfide (A).
(3) The polyarylene sulfide resin composition according to (1) or (2), wherein the polyarylene sulfide (A) has a chloroform extractable component content of 0.5% by weight or more and 2.0% by weight or less.
(4) The polyarylene sulfide resin composition according to any one of (1) to (3), wherein the thermoplastic elastomer (B) is (B1) a glycidyl group-containing copolymer having as copolymerization components an α-olefin and a glycidyl ester of an α,β-unsaturated acid, and (B2) an ethylene/α-olefin copolymer having as copolymerization components ethylene and an α-olefin having from 3 to 20 carbon atoms.
(5) The polyarylene sulfide resin composition according to any one of (1) to (4), wherein the polyarylene sulfide (A) has a branched and crosslinked structure derived from a polyhalogenated aromatic compound having three or more halogen substituents per molecule.
(6) A molded article made of the polyarylene sulfide resin composition according to any one of (1) to (5).
(7) The molded product according to (6) above, characterized in that the molded product is any plumbing part selected from the group consisting of residential plumbing equipment parts, toilet parts, water heater parts, bath parts, pump parts, and water meter parts.

According to the present invention, by blending PAS having a specific melt viscosity, a high cooling crystallization temperature, a high functional group content, and a specific degree of dispersion with a thermoplastic elastomer in a specific ratio, it is possible to provide a polyarylene sulfide resin composition that has low flash during molding, excellent fluidity, and continuous moldability while maintaining high impact resistance.

The polyarylene sulfide resin composition of the present invention has excellent impact resistance, low flash properties, and continuous moldability, and is therefore useful for electrical and electronic equipment, precision machinery equipment, water-related parts, office equipment, automobile and vehicle-related parts, building materials, packaging materials, furniture, and daily necessities, particularly water-related parts and automobile applications.

FIG. 2 is a schematic diagram of a molded product used in the evaluation of continuous moldability in the examples.

The following describes in detail the embodiments of the present invention.

(A) Polyarylene sulfide The PAS in the present invention is a homopolymer or copolymer having a repeating unit of the formula -(Ar-S)- as a main constituent unit, preferably containing 80 mol % or more of said repeating unit. Ar may be any of the units represented by the following formulae (A) to (K), among which formula (A) is particularly preferred.

(R1 and R2 are substituents selected from hydrogen, alkyl groups, alkoxy groups, and halogen groups, and R1 and R2 may be the same or different.)

This repeating unit is the main constituent unit, and the polymer contains branched units or crosslinked units represented by the following formulas (L) to (N). The copolymerization amount of these branched units or crosslinked units is preferably in the range of 0.10 mol% or more and 1.00 mol% or less per mole of -(Ar-S)- units. From the viewpoint of obtaining a high molecular weight PAS, the lower limit of the copolymerization amount of the branched units or crosslinked units is preferably 0.10 mol% or more, more preferably 0.20 mol% or more, and even more preferably 0.30 mol% or more. On the other hand, from the viewpoint of preventing gelation of the polymer, the upper limit of the copolymerization amount of the branched units or crosslinked units is preferably 1.00 mol% or less, more preferably 0.80 mol% or less, and even more preferably 0.60 mol% or less.

In addition, the PAS in the present invention may be a random copolymer, a block copolymer, or a mixture thereof that contains the above repeating units.

Representative examples of these include polyphenylene sulfide, polyphenylene sulfide sulfone, polyphenylene sulfide ketone, their random copolymers, block copolymers, and mixtures thereof. Particularly preferred PASs have the p-phenylene sulfide unit shown below as the main structural unit of the polymer.

Examples include polyphenylene sulfide resins containing 80 mol % or more, particularly 90 mol % or more.

The method for producing PAS of the present invention is described in detail below.

First, let us explain the raw materials used in the production of PAS.

[Sulfidizing agent]
The sulfidizing agent used in the present invention may be any agent capable of introducing a sulfide bond into a halogenated aromatic compound, and examples thereof include alkali metal sulfides, alkali metal hydrosulfides, and hydrogen sulfide.

Specific examples of alkali metal sulfides include lithium sulfide, sodium sulfide, potassium sulfide, rubidium sulfide, cesium sulfide, and mixtures of two or more of these. Of these, lithium sulfide and/or sodium sulfide are preferred, with sodium sulfide being more preferred. These alkali metal sulfides can be used as hydrates or aqueous mixtures, or in the form of anhydrides. An aqueous mixture refers to an aqueous solution, or a mixture of an aqueous solution and a solid component, or a mixture of water and a solid component. Generally available, inexpensive alkali metal sulfides are hydrates or aqueous mixtures, so it is preferable to use alkali metal sulfides in such a form.

Specific examples of alkali metal hydrosulfides include lithium hydrosulfide, sodium hydrosulfide, potassium hydrosulfide, rubidium hydrosulfide, cesium hydrosulfide, and mixtures of two or more of these. Among these, lithium hydrosulfide and/or sodium hydrosulfide are preferred, and sodium hydrosulfide is more preferred.

Alkali metal sulfides prepared in a reaction system from an alkali metal hydrosulfide and an alkali metal hydroxide can also be used. Alkali metal sulfides prepared in advance by contacting an alkali metal hydrosulfide with an alkali metal hydroxide can also be used. These alkali metal hydrosulfides and alkali metal hydroxides can be used as hydrates or aqueous mixtures, or in the form of anhydrides, with hydrates or aqueous mixtures being preferred from the standpoint of ease of availability and cost.

Alkali metal sulfides prepared in the reaction system from an alkali metal hydroxide such as lithium hydroxide or sodium hydroxide and hydrogen sulfide can also be used. Alkali metal sulfides prepared in advance by contacting an alkali metal hydroxide such as lithium hydroxide or sodium hydroxide with hydrogen sulfide can also be used. Hydrogen sulfide can be used in any form, whether it is a gas, liquid, or aqueous solution.

[Dihalogenated aromatic compounds]
When producing the PAS of the present invention, a dihalogenated aromatic compound is used. Examples of the dihalogenated aromatic compound to be used include dihalogenated benzenes such as p-dichlorobenzene, o-dichlorobenzene, m-dichlorobenzene, p-dibromobenzene, o-dibromobenzene, m-dibromobenzene, 1-bromo-4-chlorobenzene, and 1-bromo-3-chlorobenzene, and dihalogenated aromatic compounds containing substituents other than halogen such as 1-methoxy-2,5-dichlorobenzene, 1-methyl-2,5-dichlorobenzene, 1,4-dimethyl-2,5-dichlorobenzene, 1,3-dimethyl-2,5-dichlorobenzene, 2,5-dichlorobenzoic acid, 3,5-dichlorobenzoic acid, 2,5-dichloroaniline, and 3,5-dichloroaniline. Among them, dihalogenated aromatic compounds mainly composed of p-dihalogenated benzene, typified by p-dichlorobenzene, are preferred. From the viewpoint of preventing depolymerization of PAS during polymerization, the lower limit of the amount of dihalogenated aromatic compound is preferably 0.99 mol or more per 1.00 mol of sulfidizing agent, more preferably 1.00 mol or more. From the viewpoint of obtaining high molecular weight PAS, the upper limit of the amount of dihalogenated aromatic compound is preferably 1.03 mol or less per 1.00 mol of sulfidizing agent, more preferably 1.02 mol or less. The dihalogenated aromatic compound may be used alone or as a mixture of two or more different types.

[Branching/Crosslinking Agent]
In the production of the PAS of the present invention, the use of a branching/crosslinking agent is also one of the preferred embodiments. Specific examples include polyhalogenated aromatic compounds having three or more halogens, such as 1,3,5-trichlorobenzene, 1,2,3-trichlorobenzene, 1,2,4-trichlorobenzene, 1,2,4,5-tetrachlorobenzene, hexachlorobenzene, and 1,4,6-trichloronaphthalene, and polyhalogenated aromatic compounds having three or more halogens and containing substituents other than halogens, such as 2,3,6-trichlorobenzoic acid, 2,4,5-trichlorobenzoic acid, 2,4,6-trichlorobenzoic acid, 2,3,4-trichloroaniline, and 2,4,6-trichloroaniline. Among these, trihalogenated aromatic compounds, such as 1,3,5-trichlorobenzene and 1,2,4-trichlorobenzene, are preferred from the viewpoint of increasing the crystallization temperature of the resulting PAS when cooled. When a trihalogenated aromatic compound is used as a branching/crosslinking agent, from the viewpoint of increasing the molecular weight of PAS, the amount of the trihalogenated aromatic compound is preferably 0.10 mol% or more relative to 1.00 mol of the sulfidizing agent, more preferably 0.20 mol% or more, and even more preferably 0.30 mol% or more. On the other hand, from the viewpoint of preventing the gelation of the polymer due to the increase in branching/crosslinking, the amount of the trihalogenated aromatic compound is preferably 1.00 mol% or less relative to 1.00 mol of the sulfidizing agent, more preferably 0.80 mol% or less, and even more preferably 0.60 mol% or less. The branching/crosslinking agent may be used alone or as a mixture of two or more different types.

[Organic polar solvent]
In the present invention, an organic polar solvent is used as the polymerization solvent. As the organic polar solvent to be used, an organic amide solvent can be preferably exemplified. Specific examples include N-alkylpyrrolidones such as N-methyl-2-pyrrolidone, N-ethyl-2-pyrrolidone, and N-cyclohexyl-2-pyrrolidone, caprolactams such as N-methyl-ε-caprolactam, aprotic organic solvents such as 1,3-dimethyl-2-imidazolidinone, N,N-dimethylacetamide, N,N-dimethylformamide, and hexamethylphosphoric acid triamide, and mixtures thereof, which are preferably used because of their high reaction stability. Among these, N-methyl-2-pyrrolidone and 1,3-dimethyl-2-imidazolidinone are preferred, and N-methyl-2-pyrrolidone is more preferred.

The amount of organic polar solvent used is selected from the range of 2.00 to 10.00 moles, preferably 2.25 to 6.00 moles, and more preferably 2.50 to 5.50 moles per 1.00 mole of sulfidizing agent.

[Polymerization aid]
In order to obtain a relatively high molecular weight PAS in a short time, it is also a preferred embodiment to use a polymerization aid. Here, the polymerization aid means a substance that has the effect of increasing the viscosity of the obtained PAS. Specific examples of such polymerization aids include organic carboxylates, water, alkali metal chlorides, organic sulfonates, alkali metal sulfates, alkaline earth metal oxides, alkali metal phosphates, and alkaline earth metal phosphates. These can be used alone or in combination of two or more. Among them, organic carboxylates, water, and alkali metal chlorides are preferred, and alkali metal carboxylates are preferred as organic carboxylates, and lithium chloride is preferred as alkali metal chlorides.

The alkali metal carboxylate is a compound represented by the general formula R(COOM) _n (wherein R is an alkyl group, a cycloalkyl group, an aryl group, an alkylaryl group, or an arylalkyl group having 1 to 20 carbon atoms; M is an alkali metal selected from lithium, sodium, potassium, rubidium, and cesium; and n is an integer of 1 to 3). The alkali metal carboxylate can also be used as a hydrate, an anhydride, or an aqueous solution. Specific examples of the alkali metal carboxylate include lithium acetate, sodium acetate, potassium acetate, sodium propionate, lithium valerate, sodium benzoate, sodium phenylacetate, potassium p-toluate, and mixtures thereof.

Alkali metal carboxylates may be synthesized by adding and reacting an organic acid with one or more compounds selected from the group consisting of alkali metal hydroxides, alkali metal carbonates, and alkali metal bicarbonates in approximately equal chemical equivalents. Of the above alkali metal carboxylates, lithium salts are highly soluble in the reaction system and have a large auxiliary effect, but are expensive. On the other hand, potassium, rubidium, and cesium salts are thought to have insufficient solubility in the reaction system, so sodium acetate, which is inexpensive and has moderate solubility in the polymerization system, is most preferably used.

The water used in the above polymerization aid is preferably distilled water or ion-exchanged water so as not to impair the desired chemical modification effect of PAS.

In the present invention, it is preferable to use an alkali metal carboxylate as the polymerization aid, and it is more preferable to use sodium acetate. As the lower limit of the polymerization aid, it is preferable to have 0.06 moles or more of the polymerization aid present per 1.00 moles of the sulfidizing agent. From the viewpoint of achieving a higher molecular weight, it is more preferable to have 0.10 moles or more, and even more preferable to have 0.15 moles or more. As the upper limit of the polymerization aid, it is preferable to have 0.29 moles or less per 1.00 moles of the sulfidizing agent, more preferably 0.27 moles or less, and even more preferably 0.25 moles or less. If the above preferred range is exceeded, it is not preferable because the load on wastewater treatment increases.

When water is used as a polymerization aid, it is preferable to have 0.50 moles or more of water present in the reaction vessel per 1.00 moles of sulfidizing agent. In terms of obtaining a higher molecular weight, 0.60 moles or more is more preferable, and 0.70 moles or more is even more preferable. As an upper limit when water is used as a polymerization aid, from the viewpoint of safety related to the pressure in the reaction vessel and the viewpoint of handleability related to the particle size of the obtained polymer, it is preferable to have 1.50 moles or less of water present per 1.00 moles of sulfidizing agent, more preferably 1.25 moles or less, and even more preferably 1.00 moles or less.

It is of course possible to use two or more of these polymerization aids in combination. For example, by using an alkali metal carboxylate in combination with water, it is possible to achieve a high molecular weight with smaller amounts of alkali metal carboxylate and water.

There is no particular designation for the timing of addition of these polymerization aids, and they may be added at any time during the pre-process, at the start of polymerization, or during the polymerization reaction process, which will be described later, or may be added in multiple batches. When an alkali metal carboxylate is used as the polymerization aid, it is preferable to add it at the start of the pre-process or at the start of polymerization simultaneously with other additives, as this is easier to add. When water is used as the polymerization aid, it is effective to add it during the polymerization reaction process after the dihalogenated aromatic compound and branching/crosslinking agent have been added.

[Polymerization stabilizer]
A polymerization stabilizer can be used to stabilize the polymerization reaction system and prevent side reactions. The polymerization stabilizer contributes to the stabilization of the polymerization reaction system and suppresses undesirable side reactions. One indicator of side reactions is the generation of thiophenol. The addition of a polymerization stabilizer can suppress the generation of thiophenol. Specific examples of polymerization stabilizers include compounds such as alkali metal hydroxides, alkali metal carbonates, alkaline earth metal hydroxides, and alkaline earth metal carbonates. Among these, alkali metal hydroxides such as sodium hydroxide, potassium hydroxide, and lithium hydroxide are preferred. The above-mentioned alkali metal carboxylates also act as polymerization stabilizers, and therefore are included as one of the polymerization stabilizers. In addition, when an alkali metal hydrosulfide is used as a sulfidizing agent, it is particularly preferable to use an alkali metal hydroxide at the same time, as mentioned above, but an excess of an alkali metal hydroxide relative to the sulfidizing agent can also serve as a polymerization stabilizer.

These polymerization stabilizers can be used alone or in combination of two or more. The polymerization stabilizer is usually used in a ratio of 0.02 to 0.20 mol, preferably 0.03 to 0.10 mol, and more preferably 0.04 to 0.09 mol per 1.00 mol of charged sulfidizing agent. If this ratio is too small, the stabilizing effect is insufficient, and conversely, if it is too large, it is economically disadvantageous and the polymer yield tends to decrease.

There is no particular designation for the timing of addition of the polymerization stabilizer, and it may be added at any time during the pre-process, at the start of polymerization, or during the polymerization reaction process, which will be described later. It may also be added in multiple portions, but it is more preferable to add it at the start of the pre-process or at the start of polymerization at the same time, as this is easier.

Next, a preferred method for producing the PAS of the present invention will be specifically described in order, including the pre-process, polymerization reaction process, recovery process, and post-treatment process, but of course the method is not limited to this method.

[Pre-process]
When producing the PAS of the present invention, the sulfidizing agent is used in the form of a hydrate, and it is preferable to heat the mixture containing the organic polar solvent and the sulfidizing agent and remove excess water from the system before adding the dihalogenated aromatic compound and the branching/crosslinking agent.

As described above, the sulfidizing agent may be prepared in situ in the reaction system from an alkali metal hydrosulfide and an alkali metal hydroxide, or in a tank separate from the polymerization tank. There are no particular limitations to this method, but a preferred method is to add an alkali metal hydrosulfide and an alkali metal hydroxide to an organic polar solvent in an inert gas atmosphere at room temperature to 150°C, preferably room temperature to 100°C, and then heat the mixture to at least 150°C or higher, preferably 180°C to 260°C, under normal pressure or reduced pressure, to distill off water. A polymerization aid may be added at this stage. These raw materials may be charged in any order, or simultaneously. Toluene or the like may be added to promote the distillation of water.

At the end of the previous step, i.e., before the polymerization reaction step, the amount of water in the system is preferably 0.01 to 1.00 moles per 1.00 moles of charged sulfidizing agent. Here, the amount of water in the system is the amount of water charged into the polymerization system minus the amount of water removed from the polymerization system. The charged water may be in any form, such as water, an aqueous solution, or water of crystallization.

[Polymerization process]
When producing the PAS of the present invention, it is preferable to carry out a polymerization step in which the reactant prepared in the previous step is brought into contact with a dihalogenated aromatic compound and a branching/crosslinking agent in an organic polar solvent to cause a polymerization reaction.

In the polymerization step, it is preferable to have 0.06 mol to 0.29 mol of an alkali metal carboxylate per 1.00 mol of the sulfidizing agent, and to have 0.99 mol to 1.03 mol of a dihalogenated aromatic compound and 0.10 mol % to 1.00 mol % of a trihalogenated aromatic compound per 1.00 mol of the sulfidizing agent (Step 1).

Here, the alkali metal carboxylate plays a role as a polymerization aid as described above, and it is preferable to have the alkali metal carboxylate present in an amount of 0.06 mol or more, since the molecular weight of the resulting PAS is high. More preferably, it is 0.10 mol or more, and even more preferably, it is 0.15 mol or more. It is also preferable that the alkali metal carboxylate is present in an amount of 0.29 mol or less, more preferably, 0.27 mol or less, and even more preferably, 0.25 mol or less. If the amount exceeds the above preferred range, the load on the wastewater treatment increases, which is not preferable. Also, as described above, the alkali metal carboxylate may be added in a previous process.

In addition, in the polymerization process, it is preferable to have 0.10 mol % or more and 1.00 mol % or less of a trihalogenated aromatic compound present per 1.00 mol of a sulfidizing agent.

Here, the trihalogenated aromatic compound plays the role of a branching/crosslinking agent as described above. From the viewpoint of increasing the molecular weight of PAS, the amount of the trihalogenated aromatic compound is preferably 0.10 mol% or more relative to 1.00 mol of the sulfidizing agent, more preferably 0.20 mol% or more, and even more preferably 0.30 mol% or more. On the other hand, from the viewpoint of preventing the gelation of the polymer due to increased branching/crosslinking, the amount of the trihalogenated aromatic compound is preferably 1.00 mol% or less relative to 1.00 mol of the sulfidizing agent, more preferably 0.80 mol% or less, and even more preferably 0.60 mol% or less.

When starting the polymerization reaction process, the organic polar solvent, the sulfidizing agent, the dihalogenated aromatic compound, and the branching/crosslinking agent are mixed, preferably in an inert gas atmosphere, at a temperature range of 25°C to 240°C, and preferably 100°C to 230°C. A polymerization aid may be added at this stage. These raw materials may be charged in any order, or simultaneously.

The mixture is usually heated to a temperature range of 200°C to 280°C. There are no particular restrictions on the heating rate, but a rate of 0.01°C/min to 5°C/min is usually selected, with a range of 0.1°C/min to 3°C/min being more preferable. As long as it is within the range of the heating rate described above, it does not necessarily have to be a constant rate, and there may be a constant temperature section, or the heating may be performed in multiple stages without any problems, and there may be a section where the heating rate becomes temporarily negative as long as it does not impair the essence of the present invention.

Generally, the temperature is finally raised to 250°C to 280°C or less, and the reaction is carried out at that temperature for usually 0.25 hours to 50 hours, preferably 0.5 hours to 20 hours.

Before reaching the final temperature, for example, a method of reacting at 200°C to 250°C for a certain time and then raising the temperature to 250°C to 280°C or less is effective in obtaining a higher molecular weight. In this case, the reaction time at 200°C to 250°C is usually selected in the range of 0.25 hours to 20 hours, preferably 0.25 hours to 10 hours. In addition, it is desirable to carry out the reaction so that the conversion rate of the halogenated aromatic compound in the system at the time of raising the temperature to the range of 250°C to 280°C after reacting for a certain time at 200°C to 250°C is 60% or more, preferably 70% or more, more preferably 80% or more, and even more preferably 90% or more. The conversion rate of the halogenated aromatic compound (abbreviated as HA here) is a value calculated by the following formula. The amount of HA remaining can usually be determined by gas chromatography.
(A) When a halogenated aromatic compound is added in excess relative to an alkali metal sulfide in a molar ratio, conversion rate = [HA charge amount (moles) - remaining HA amount (moles)] / [HA charge amount (moles) - excess HA amount (moles)]
(B) In cases other than (A) above, conversion rate = [charged amount of HA (moles) - remaining amount of HA (moles)] / [charged amount of HA (moles)].

In the present invention, the polymerization time in the polymerization step is usually preferably 60 minutes or more, more preferably 120 minutes or more, from the viewpoint of increasing the molecular weight of the PAS. On the other hand, the upper limit of the polymerization time is preferably 240 minutes or less, more preferably 210 minutes or less, and even more preferably 180 minutes or less, from the viewpoint of productivity. The polymerization time here includes the time required for the temperature to rise and fall within the temperature range of 200°C to 280°C from the time the sulfidizing agent and the halogenated aromatic compound are charged until the polymerization reaction product is discharged from the reaction vessel.

In the polymerization step, it is preferable that 0.50 moles or more of water is present in the reaction vessel per 1.00 moles of sulfidizing agent. In terms of obtaining a higher molecular weight, 0.60 moles or more is more preferable, and 0.70 moles or more is even more preferable. When water is used as a polymerization aid, the upper limit is preferably 1.50 moles or less of water per 1.00 moles of sulfidizing agent, more preferably 1.25 moles or less, and even more preferably 1.00 moles or less, from the viewpoint of safety related to the pressure in the reaction vessel and the viewpoint of handling related to the particle size of the obtained polymer. The amount of water in the polymerization step represents the amount of water in the temperature range of 250°C to 280°C in the polymerization step, and is the amount obtained by subtracting the amount of water removed from the polymerization system from the amount of water charged into the polymerization system and the amount of water generated by the polymerization reaction.

As a method for causing 0.50 moles or more and 1.50 moles or less of water to be present in the reaction vessel per 1.00 moles of sulfidizing agent, water may be added to the reaction vessel, or the reaction vessel may be partially opened to remove the water. A combination of these methods is also possible. From the standpoint of safety and simplicity, it is preferable to add water.

[Recovery process]
When producing the PAS of the present invention, after the polymerization is completed, solid matter is recovered from the polymerization reaction product containing the polymer, the solvent, etc. The solid matter referred to here includes not only the PAS but also water-soluble substances such as by-product salts and unreacted sulfidizing agents. Any known method may be used for the recovery method.

For example, after the polymerization reaction is completed, the mixture may be slowly cooled to recover the particulate polymer. There is no particular limit to the cooling rate, but it is usually about 0.1°C/min to 3°C/min. It is not necessary to cool at the same rate throughout the entire cooling process, and it is possible to use a method in which the mixture is slowly cooled at a rate of 0.1°C/min to 1°C/min until the polymer particles crystallize and precipitate, and then at a rate of 1°C/min or faster.

Also, one of the preferred methods is to carry out the above-mentioned recovery under quenching conditions. Among these recovery methods, a flash method is a preferred method. The flash method is a method in which the polymerization reaction product is flashed from a high-temperature, high-pressure state (usually 250°C or higher, 8 kg/cm2 ^or higher) into an atmosphere of normal pressure, reduced pressure, or pressurized pressure, and the solvent is distilled off while the polymer is recovered in powder form. The flashing here means that the polymerization reaction product is ejected from a nozzle. Specific examples of the flashing atmosphere include nitrogen or water vapor at normal pressure, and the temperature is usually selected in the range of 150°C to 250°C.

In the production of the PAS of the present invention, either a method of slowly cooling to recover particulate PAS or a method of rapidly cooling to recover powdered PAS may be used. However, since the method of slowly cooling to recover particulate PAS results in a low content of functional groups in the PAS obtained, and requires a long time for slowly cooling, the preferred method is to flash the polymerization reaction product from a high-temperature, high-pressure state into an atmosphere of normal pressure, reduced pressure, or pressurized pressure, distill off the solvent, and simultaneously rapidly cool the product to recover powdered PAS.

[Post-processing process]
The PAS may be produced through the above-mentioned polymerization and recovery steps, and then subjected to hot water treatment, acid treatment, washing with an organic solvent, or treatment with an alkali metal or alkaline earth metal.

In the present invention, since the solid obtained through the above recovery process contains not only PAS but also water-soluble substances such as by-product salts and unreacted sulfidizing agents, hot water washing is preferable. The hot water treatment is performed as follows. When hot water treatment of PAS, it is preferable to set the temperature of the hot water to 100°C or higher, more preferably 120°C or higher, even more preferably 150°C or higher, and particularly preferably 170°C or higher. Temperatures below 100°C are not preferable because the effect of the preferable chemical modification of PAS is small. In order to express the effect of the preferable chemical modification of PAS by hot water washing, it is preferable that the water used is distilled water or ion-exchanged water. There are no particular restrictions on the operation of the hot water treatment. It is performed by adding a predetermined amount of PAS to a predetermined amount of water, heating and stirring in a pressure vessel, or by continuously performing hot water treatment. The ratio of PAS to water is preferably higher, but usually a bath ratio of 200g or less of PAS per 1 liter of water (weight of cleaning solution relative to the weight of dry PAS) is selected.

In the present invention, from the viewpoint of obtaining a PAS having a high functional group content and a high cooling crystallization temperature, it is preferable to subject the PAS to an acid treatment. The acid treatment is performed as follows. There are no particular limitations on the acid used in the acid treatment of the PAS, so long as it does not have the effect of decomposing the PAS, and examples of the acid include acetic acid, hydrochloric acid, sulfuric acid, phosphoric acid, silicic acid, carbonic acid, and propylic acid. Of these, acetic acid and hydrochloric acid are more preferably used. On the other hand, acids that decompose and deteriorate the PAS, such as nitric acid, are not preferable.

In addition, to avoid undesirable decomposition of the reactive functional groups at the terminals, it is desirable to carry out the treatment in an inert atmosphere. Furthermore, in order to remove any remaining components, it is preferable to wash the PAS after this hot water treatment operation several times with warm water.

For example, the acid treatment method may involve immersing the PAS in an acid or an aqueous solution of an acid, and stirring or heating may be performed as necessary. For example, when using acetic acid, a sufficient effect can be obtained by immersing the PAS powder in an aqueous solution of acetic acid with a pH of 4 heated to 80°C to 200°C and stirring for 30 minutes. The pH after treatment may be 4 or higher, for example, about pH 4 to 8. In order to remove residual acid or salt from the acid-treated PAS, it is preferable to wash the PAS several times with water or hot water. The water used for washing is preferably distilled water or ion-exchanged water so as not to impair the effect of the preferable chemical modification of the PAS by the acid treatment. PAS that has been subjected to acid treatment is preferable because it has excellent reactivity during molding and has a high crystallization temperature when cooled.

When drying PAS after acid treatment, if the drying temperature is too high, the PAS particles will fuse together and the specific surface area will become smaller, and there is a tendency that sufficient cleaning effect cannot be achieved in the organic solvent cleaning described below. Therefore, the lower limit of the drying temperature is preferably 70°C or higher, more preferably 100°C or higher, and even more preferably 120°C or higher. The upper limit is preferably 170°C or lower, and more preferably 150°C or lower. When the drying temperature of PAS is in the above preferred range, the specific surface area of the PAS after drying tends to be large, and oligomers in the PAS tend to be easily washed and removed in the organic solvent cleaning described below. Since oligomers in PAS adhere to and accumulate on the mold during molding and cause mold contamination, it is preferable that they are washed and removed. In addition, there is a tendency that drying can be performed efficiently in a short time. In addition, it is preferable that the atmosphere during drying is a non-oxidizing condition, and an inert gas atmosphere such as nitrogen, helium, and argon is preferable, and in particular, a nitrogen atmosphere is more preferable from the viewpoint of economy and ease of handling. By drying the PAS in such an atmosphere, there is a tendency that denaturation due to oxidation of the PAS can be prevented.

There is no particular restriction on the drying time, but an example of a lower limit is 0.5 hours or more, and 1 hour or more is preferable. An upper limit is preferably 50 hours or less, more preferably 20 hours or less, and even more preferably 10 hours or less. When the drying time of the PAS is within the above preferred range, the PAS can be produced industrially and efficiently.

Here, there is no particular restriction on the dryer used for drying, and a general vacuum dryer or hot air dryer can be used. It is also possible to use a rotary type or a heating device with stirring blades, a fluidized bed dryer, etc. From the viewpoint of drying the PAS efficiently and uniformly, it is preferable to dry it using a rotary type or a heating device with stirring blades.

In the present invention, it is preferable to wash the PAS with an organic solvent. By washing with an organic solvent, the oligomers in the obtained PAS can be reduced and the amount of chloroform extractable components can be set within a preferred range. Details will be described later. Washing with an organic solvent is as follows. There are no particular restrictions on the organic solvent used to wash the PAS, so long as it does not have the effect of decomposing the PAS. Examples of organic solvents used for cleaning PAS include nitrogen-containing polar solvents such as N-methyl-2-pyrrolidone, dimethylformamide, dimethylacetamide, 1,3-dimethylimidazolidinone, hexamethylphosphoramide, and piperazinones; sulfoxide-sulfone solvents such as dimethyl sulfoxide, dimethyl sulfone, and sulfolane; ketone solvents such as acetone, methyl ethyl ketone, diethyl ketone, and acetophenone; ether solvents such as dimethyl ether, dipropyl ether, dioxane, and tetrahydrofuran; halogen-based solvents such as chloroform, methylene chloride, trichloroethylene, ethylene dichloride, perchloroethylene, monochloroethane, dichloroethane, tetrachloroethane, perchloroethane, and chlorobenzene; alcohol-phenol solvents such as methanol, ethanol, propanol, butanol, pentanol, ethylene glycol, propylene glycol, phenol, cresol, polyethylene glycol, and polypropylene glycol; and aromatic hydrocarbon solvents such as benzene, toluene, and xylene. Among these organic solvents, it is particularly preferable to use N-methyl-2-pyrrolidone, acetone, dimethylformamide, and chloroform. These organic solvents are used alone or in combination of two or more.

For example, the method of washing with an organic solvent includes immersing the PAS in the organic solvent, and stirring or heating can be performed as necessary. There is no particular restriction on the washing temperature when washing the PAS with an organic solvent, and any temperature between room temperature and about 300°C can be selected. The higher the washing temperature, the higher the washing efficiency tends to be, but usually a washing temperature between room temperature and 150°C is sufficient to obtain the desired effect. It is also possible to wash under pressure in a pressure vessel at a temperature above the boiling point of the organic solvent. There is also no particular restriction on the washing time. Although it depends on the washing conditions, in the case of batch washing, washing for 5 minutes or more usually provides a sufficient effect. It is also possible to wash in a continuous manner. The post-treatment step is preferably performed by either acid treatment, hot water treatment, or washing with an organic solvent, and it is preferable to use two or more types of treatments in combination from the viewpoint of removing impurities.

The water content of the PAS before washing with an organic solvent is preferably 30% by weight or less. Since water is a poor solvent for the chloroform extractable components in the PAS, reducing the water content of the PAS tends to reduce the chloroform extractable components when the PAS is washed with an organic solvent. In addition, when the organic solvent used to wash the PAS is a non-water-soluble organic solvent such as chloroform or toluene, a stable cleaning effect tends to be obtained regardless of the water content of the PAS, so it is not necessary to make the water content of the PAS 30% by weight or less. However, considering that N-methyl-2-pyrrolidone, which is particularly preferably used from the viewpoint of ease of availability, is a water-soluble organic solvent, it can be said that reducing the water content in the PAS is a more preferable method. Here, the lower limit of the water content of the PAS before washing with an organic solvent is preferably as low as possible in order to enhance the cleaning effect, and 0% by weight, which means that no water is contained in the PAS at all, is most preferable. On the other hand, the upper limit can be exemplified as 10% by weight or less, more preferably 5% by weight or less, and even more preferably 1% by weight or less. In step 3, when the water content of the PAS before washing with an organic solvent is in the above-mentioned preferred range, the amount of chloroform extractable components in the PAS tends to be more easily reduced when a water-soluble organic solvent is used for washing the PAS. As described above, an example of a method for reducing the water content to 30% by weight or less is to dry the PAS after acid treatment.

Here, the moisture content of the PAS in the present invention is measured by the Karl Fischer method in accordance with Japanese Industrial Standard JIS K 7251.

Examples of methods for treating with alkali metals and alkaline earth metals include adding alkali metal salts and alkaline earth metal salts before, during, and after the previous process, adding alkali metal salts and alkaline earth metal salts to the polymerization tank before, during, and after the polymerization process, or adding alkali metal salts and alkaline earth metal salts at the beginning, middle, or end of the washing process. The easiest method is to add alkali metal salts and alkaline earth metal salts after removing residual oligomers and residual salts by organic solvent washing or warm or hot water washing. The alkali metals and alkaline earth metals are preferably introduced into the PAS in the form of alkali metal ions and alkaline earth metal ions such as acetates, hydroxides, and carbonates. It is also preferable to remove excess alkali metal salts and alkaline earth metal salts by washing with warm water, etc. The concentration of alkali metal ions and alkaline earth metal ions when introducing the alkali metals and alkaline earth metals is preferably 0.001 mmol or more per 1 g of PAS, and more preferably 0.01 mmol or more. The temperature is preferably 50°C or higher, more preferably 75°C or higher, and particularly preferably 90°C or higher. There is no particular upper limit to the temperature, but from the viewpoint of operability, it is usually preferable for the temperature to be 280°C or lower. The bath ratio (weight of cleaning solution to weight of dry PAS) is preferably 0.5 or higher, more preferably 3 or higher, and even more preferably 5 or higher.

In the present invention, it is preferable to carry out a post-treatment process in which the solid material containing polyarylene sulfide is washed with water, then subjected to an acid treatment, and then, following the acid treatment, a process in which the polyarylene sulfide is washed with an organic solvent. This makes it possible to efficiently remove oligomer components and adjust the amount of chloroform-extractable components in PAS.

[Thermal oxidation crosslinking treatment]
In addition, the PAS in the present invention can also be used after being polymerized by a thermal oxidation crosslinking treatment, which involves heating in an oxygen atmosphere after the completion of polymerization or heating with the addition of a crosslinking agent such as a peroxide.

When dry heat treatment is performed for the purpose of increasing the molecular weight by thermal oxidation crosslinking, the temperature is preferably 160°C to 260°C, more preferably 170°C to 250°C. The oxygen concentration is preferably 5% by volume or more, and even more preferably 8% by volume or more. There is no particular upper limit to the oxygen concentration, but the limit is about 50% by volume. The treatment time is preferably 0.5 hours to 100 hours, more preferably 1 hour to 50 hours, and even more preferably 2 hours to 25 hours. The heat treatment device may be a normal hot air dryer or a rotary type or a heating device with a stirring blade. For efficient and more uniform treatment, it is preferable to use a rotary type or a heating device with a stirring blade.

It is also possible to carry out a dry heat treatment in order to suppress thermal oxidative crosslinking and remove volatiles. The temperature is preferably 130°C to 250°C, more preferably 160°C to 250°C. In this case, the oxygen concentration is preferably less than 5% by volume, and even more preferably less than 2% by volume. The treatment time is preferably 0.5 hours to 50 hours, more preferably 1 hour to 20 hours, and even more preferably 1 hour to 10 hours. The heat treatment device may be a normal hot air dryer or a rotary or stirring blade-equipped heating device. For efficient and more uniform treatment, it is more preferable to use a rotary or stirring blade-equipped heating device.

[Features of PAS]
The PAS of the present invention is characterized in that the melt flow rate measured in accordance with ASTM D 1238-70 under conditions of 315°C and a load of 5000 g is 50 g/10 min or more and 300 g/10 min or less, the temperature-lowering crystallization temperature (Tmc) measured at a temperature-lowering rate of 20°C/min with a differential scanning calorimeter (DSC) is 200°C or more and 230°C or less, the carboxyl group content is 30 μmol/g or more and 100 μmol/g or less, and further the dispersity expressed by weight average molecular weight/number average molecular weight is 6.0 or more and 15.0 or less.

If the melt flow rate (hereafter abbreviated as MFR) of PAS exceeds 300g/10min, there will be problems with mechanical strength and toughness during molding. On the other hand, if the lower limit of MFR is below 50g/10min, the melt fluidity will be low, and the PAS will not be able to enter the mold during injection molding, making it difficult to obtain a good molded product. In addition, the burr reduction effect will be reduced because the pressure required during molding will need to be increased. MFR is a value measured in accordance with ASTM D 1238-70 at a temperature of 315°C and a load of 5000g.

If the crystallization temperature (Tmc) of PAS measured at a cooling rate of 20°C/min falls below 200°C, the crystallization rate slows down, the time cycle during molding decreases, and the solidification rate slows down, reducing the effect of reducing burrs, which is undesirable. On the other hand, if the Tmc exceeds 230°C, the crystallization rate increases, causing a problem of a decrease in crystallinity. In addition, if the Tmc is not in the range of 200 to 230°C, the mold release force during molding increases, which is undesirable. In general, the more the branched/crosslinked structure increases, the lower the crystallization temperature tends to be, so the more the amount of polyhalogenated aromatic compound having three or more halogens is mixed, the lower the Tmc. In addition, in the manufacturing process of PAS, the crystallization temperature is improved by performing acid treatment in the post-treatment process. The reason for this is unclear, but it is assumed that the crystallization temperature is lowered due to the influence of the metal species at the polymer end.

The carboxyl group content of the PAS is preferably 30 μmol/g or more, more preferably 35 μmol/g or more, and most preferably 40 μmol/g or more in order to obtain sufficient reactivity between the PAS and different materials. If the carboxyl group content is 30 μmol/g or less, the reactivity with the thermoplastic elastomer (B) decreases, the impact resistance and the effect of reducing burrs also decrease, and resin leakage from the nozzle tip during molding tends to occur, leading to poor continuous moldability. On the other hand, if the carboxyl group content exceeds 100 μmol/g, the amount of volatile components during molding tends to increase, and voids tend to occur in the molded product, which is not preferable. In the present invention, the carboxyl group content is in the above-mentioned preferred range by using a trihalogenated aromatic compound as a branching/crosslinking agent. The reason for this is unclear, but it is presumed to be due to the high reactivity of the trihalogenated aromatic compound. In addition, the carboxyl group content when a trihalogenated aromatic compound is not used is generally lower than when a trihalogenated aromatic compound is used. The carboxyl group content of PAS is measured as follows:

The carboxyl group content of PAS can be estimated by measuring an amorphous film of the PAS resin using FT-IR (IR-810 infrared spectrophotometer manufactured by JASCO Corporation) and comparing the absorption at around 1,730 cm ^{−1 due to the carboxyl group with the absorption at around 1,900 cm −1 due} to the benzene ring.

The dispersity (hereinafter abbreviated as Mw/Mn) of the PAS of the present invention, expressed by weight average molecular weight (Mw)/number average molecular weight (Mn), is 6.0 or more. It is more preferable that it is 6.5 or more, and even more preferable that it is 7.0 or more. The larger the Mw/Mn, the higher the non-Newtonianity, and therefore the better the molding processability during extrusion molding and blow molding. On the other hand, the upper limit of Mw/Mn is 15.0 or less. It is preferably 13.0 or less, and even more preferably 12.0 or less. In the present invention, by using a trihalogenated aromatic compound as a branching/crosslinking agent, Mw/Mn can be set to the above-mentioned preferred range. In addition, when the amount of the trihalogenated aromatic compound is increased, Mw/Mn increases. In general, Mw/Mn is 5.0 or less when no branching/crosslinking agent is used. The Mw/Mn value referred to here is a value measured using gel permeation chromatography (GPC) with 1-chloronaphthalene as the eluent at a column temperature of 210°C and converted to a polystyrene standard.

In addition, the PAS of the present invention preferably has a chloroform extractable component amount of 0.5% by weight or more and 2.0% by weight or less. The chloroform extractable component in the present invention refers to an oligomer component mainly contained in the PAS, and is a component consisting of cyclic PAS and linear PAS oligomer. There is no particular limit to the ratio of these components. These components are also volatile components that cause mold staining during injection molding. By setting the chloroform extractable component amount to 2.0% by weight or less, the amount of low molecular weight oligomers is reduced, and burrs are reduced, and mold staining during molding of the PAS resin composition can also be suppressed. If the lower limit of the chloroform extractable component amount in the PAS is 0.5% by weight or less, the amount of oligomers is too small, so the melt viscosity is likely to increase, the fluidity is reduced, and the pressure during molding must be increased, so the burr reduction effect is also reduced. In order to adjust the amount of PAS oligomers having functional groups and adjust the functional group content of the PAS, the amount of chloroform extractable component is more preferably 0.8% by weight or more. The PAS oligomers mentioned here are removed by washing the PAS with an organic polar solvent. The amount of chloroform extractable components is calculated by measuring the weight of the components obtained after weighing out 10 g of polymer and performing Soxhlet extraction with 100 g of chloroform for 3 hours, distilling off the chloroform from the extract, and calculating the ratio to the weight of the charged polymer.

From the viewpoint of the balance between moldability and burr reduction effect, the PAS of the present invention preferably has an ash content of 0.20% by weight or less, more preferably 0.15% by weight or less, and most preferably 0.12% by weight or less. A high ash content means that the metal content in the PAS is high, but if the metal content is too low, moldability tends to decrease and mold fouling tends to worsen due to increased gas generation. On the other hand, if the metal content is high, reactivity with (B) thermoplastic elastomer tends to decrease, and impact resistance and burr reduction effect tend to decrease. The ash content is measured when the PAS is finally obtained to confirm whether it is within the target value.

(B) Thermoplastic Elastomer The polyarylene sulfide resin composition of the present invention is prepared by blending 1 to 50 parts by weight of (B) thermoplastic elastomer with 100 parts by weight of the polyarylene sulfide (A).

The preferred lower limit of the amount of (B) thermoplastic elastomer blended is 3 parts by weight or more, more preferably 5 parts by weight or more, and most preferably 6 parts by weight or more, per 100 parts by weight of (A) polyarylene sulfide resin. By using this preferred range, the impact resistance strength of the molded product is improved. The preferred upper limit is preferably 45 parts by weight or less, more preferably 32 parts by weight or less, and most preferably 15 parts by weight or less, per 100 parts by weight of (A) polyarylene sulfide resin. By using this preferred range, a resin composition with excellent impact resistance, moldability, and continuous molding can be obtained.

(B) Examples of thermoplastic elastomers include ethylene/propylene copolymers, ethylene/1-butene copolymers, ethylene/1-octene copolymers, ethylene/propylene/conjugated diene copolymers, ethylene/ethyl acrylate copolymers, ethylene/butyl acrylate copolymers, ethylene/methacrylic acid copolymers, ethylene/glycidyl copolymers, ethylene/methacrylic acid/glycidyl copolymers, ethylene/vinyl acetate/glycidyl methacrylate copolymers, ethylene/ethyl acrylate-g-methyl methacrylate/butyl acrylate copolymers, ethylene/ethyl acrylate-g-methyl methacrylate copolymers, ethylene/ethyl acrylate-g-maleic anhydride copolymers, ethylene/methyl methacrylate-g-maleic anhydride copolymers, ethylene/ethyl acrylate-g-maleimide copolymers, ethylene/propylene-g-maleic anhydride copolymers, and ethylene/butene-1-g-maleic anhydride copolymers. These can be used alone or in the form of a mixture.

The thermoplastic elastomer is preferably a mixture containing (B1) a glycidyl group-containing copolymer having an α-olefin and an α,β-unsaturated glycidyl ester as copolymerization components (hereinafter, sometimes referred to as (B1) glycidyl group-containing copolymer), and (B2) an ethylene-α-olefin copolymer having ethylene and an α-olefin having 3 to 20 carbon atoms as copolymerization components (hereinafter, sometimes referred to as (B2) ethylene-α-olefin copolymer).

The (B1) glycidyl group-containing copolymer is a copolymer obtained by copolymerizing an α-olefin, a glycidyl ester of an α,β-unsaturated acid, and, if necessary, an unsaturated monomer copolymerizable therewith. It is preferable that the (B1) glycidyl group-containing copolymer contains a total of 60% by weight or more of α-olefin and glycidyl ester of an α,β-unsaturated acid in all copolymerization components. Examples of α-olefins include ethylene, propylene, 1-butene, 1-pentene, and 1-octene. Two or more of these may be used. Examples of glycidyl esters of α,β-unsaturated acids include glycidyl acrylate, glycidyl methacrylate, glycidyl ethacrylate, and glycidyl itaconate. Two or more of these may be used. Glycidyl methacrylate is preferably used. Examples of unsaturated monomers that can be copolymerized with the above components include vinyl ethers, vinyl esters such as vinyl acetate and vinyl propionate, acrylic and methacrylic acid esters such as methyl, ethyl, propyl, and butyl, acrylonitrile, and styrene. Two or more of these may be used.

Preferred examples of the glycidyl group-containing copolymer (B1) include ethylene/glycidyl methacrylate copolymer, ethylene/glycidyl methacrylate/vinyl acetate copolymer, ethylene/glycidyl methacrylate/acrylic acid ester copolymer, and ethylene/glycidyl acrylate/vinyl acetate copolymer. Two or more of these may be used.

From the viewpoint of further improving the impact strength of molded articles obtained from the polyphenylene sulfide resin composition of the present invention, the glycidyl group-containing copolymer (B1) is preferably a glycidyl group-containing binary copolymer having an α-olefin and a glycidyl ester of an α,β-unsaturated acid as copolymerization components, and more specifically, an ethylene/glycidyl methacrylate copolymer is more preferred. A particularly preferred ethylene/glycidyl methacrylate copolymer is available from Sumitomo Chemical Co., Ltd. under the trade name Bondfast (registered trademark), for example Bondfast E.

The ethylene/α-olefin copolymer (B2) is obtained by copolymerizing ethylene with an α-olefin having 3 to 20 carbon atoms. In addition to the ethylene and the α-olefin having 3 to 20 carbon atoms, other components can be added within a range that does not adversely affect the effects of the present invention. In this case, one having a glycidyl ester of an α,β-unsaturated acid as a copolymerization component as the other component is considered to be the glycidyl group-containing copolymer (B1). In other words, the ethylene/α-olefin copolymer (B2) does not have a glycidyl group.

Examples of the α-olefin having 3 to 20 carbon atoms in the ethylene/α-olefin copolymer (B2) include propylene, isobutylene, 1-butene, 1-pentene, 1-hexene, 4-methyl-1-pentene, 1-heptene, 1-octene, 1-nonene, and 1-decene, with 1-butene and 1-octene being particularly preferred.

(B2) As the ethylene/α-olefin copolymer, an ethylene/1-butene copolymer is preferred, and a particularly preferred ethylene/1-butene copolymer is available from Mitsui Chemicals, Inc. under the trade name Tafmer (registered trademark), for example, Tafmer (registered trademark) A0550S.

(C) Organic silane coupling agent having at least one functional group selected from the group consisting of epoxy group, amino group, and isocyanate group For the purpose of improving mechanical strength, toughness, etc., the polyarylene sulfide resin composition of the present invention can be blended with 0.05 to 5 parts by weight of (C) organic silane coupling agent having at least one functional group selected from the group consisting of epoxy group, amino group, and isocyanate group (hereinafter, may be abbreviated as organic silane coupling agent having functional group (C)) per 100 parts by weight of polyarylene sulfide (A) as necessary. A more preferable lower limit of the blending amount of the organic silane coupling agent having functional group (C) can be exemplified as 0.1 parts by weight or more, and from the viewpoint of obtaining a sufficient mechanical strength improvement effect, 0.2 parts by weight or more can be exemplified more preferably. A preferable upper limit of the blending amount of the organic silane coupling agent having functional group (C) is more preferably 3 parts by weight or less, and from the viewpoint of suppressing excessive thickening, 2 parts by weight or less can be exemplified more preferably.

Specific examples of organic silane coupling agents having such a functional group (C) include epoxy group-containing alkoxysilane compounds such as γ-glycidoxypropyltrimethoxysilane, γ-glycidoxypropyltriethoxysilane, and 2-(3,4-epoxycyclohexyl)ethyltrimethoxysilane; isocyanate group-containing alkoxysilane compounds such as γ-isocyanatepropyltriethoxysilane, γ-isocyanatepropyltrimethoxysilane, γ-isocyanatepropylmethyldimethoxysilane, γ-isocyanatepropylmethyldiethoxysilane, γ-isocyanatepropylethyldimethoxysilane, γ-isocyanatepropylethyldiethoxysilane, and γ-isocyanatepropyltrichlorosilane; and amino group-containing alkoxysilane compounds such as γ-(2-aminoethyl)aminopropylmethyldimethoxysilane, γ-(2-aminoethyl)aminopropyltrimethoxysilane, γ-aminopropyltrimethoxysilane, and γ-aminopropyltriethoxysilane. Among organic silane coupling agents having an epoxy group, 2-(3,4-epoxycyclohexyl)ethyltrimethoxysilane is more preferred from the viewpoint of exhibiting superior mechanical strength and resistance to moist heat. (C) Comparing the functional groups of organic silane coupling agents having functional groups, organic silane coupling agents having an isocyanate group are preferred from the viewpoint of exhibiting superior tensile elongation and impact strength compared to silane coupling agents having an epoxy group or an amino group. On the other hand, silane coupling agents having an amino group are preferred from the viewpoint of obtaining an excellent burr reduction effect and conforming to standards for water use and food standards.

Other Additives Furthermore, the polyarylene sulfide resin composition used in the present invention can also be used by blending fibrous and/or non-fibrous fillers within the range that does not impair the effects of the present invention. Specific examples of such fillers include fibrous fillers such as glass fibers, carbon fibers, carbon nanotubes, carbon nanohorns, cellulose nanofibers, potassium titanate whiskers, zinc oxide whiskers, calcium carbonate whiskers, wollastonite whiskers, aluminum borate whiskers, aramid fibers, alumina fibers, silicon carbide fibers, ceramic fibers, asbestos fibers, gypsum fibers, and metal fibers; and non-fibrous fillers such as fullerene, talc, wollastonite, zeolite, sericite, mica, kaolin, clay, pyrophyllite, bentonite, asbestos, silicates such as alumina silicate, silicon oxide, magnesium oxide, alumina, zirconium oxide, titanium oxide, and iron oxide; carbonates such as calcium carbonate, magnesium carbonate, and dolomite; sulfates such as calcium sulfate and barium sulfate; glass beads, glass flakes, glass powder, ceramic beads, boron nitride, silicon carbide, carbon black, and silica and graphite. These may be hollow, and two or more of these fillers may be used in combination. These fillers may also be pretreated with coupling agents such as isocyanate compounds, organic silane compounds, organic titanate compounds, organic borane compounds, and epoxy compounds before use. The preferred upper limit of the fibrous and/or non-fibrous filler is preferably 15 parts by weight or less, more preferably 10 parts by weight or less, even more preferably 5 parts by weight or less, and most preferably 0 parts by weight, relative to 100 parts by weight of the polyarylene sulfide (A) from the viewpoint of impact resistance. If the amount of fibrous and/or non-fibrous filler exceeds 15 parts by weight relative to 100 parts by weight of the polyarylene sulfide resin (A), impact resistance decreases, which is not preferred.

Furthermore, in order to maintain high heat resistance and thermal stability, the polyarylene sulfide resin composition of the present invention is preferably blended with one or more antioxidants selected from phenol-based and phosphorus-based compounds within a range that does not impair the effects of the present invention. The blending amount of such antioxidant is preferably 0.01 parts by weight or more, particularly 0.02 parts by weight or more, per 100 parts by weight of polyarylene sulfide resin (A) from the viewpoint of heat resistance improvement effect, and is preferably 5 parts by weight or less, particularly 1 part by weight or less, from the viewpoint of gas components generated during molding. In addition, the combined use of phenol-based and phosphorus-based antioxidants is particularly preferable, as it has a large effect of maintaining heat resistance and thermal stability.

Furthermore, the polyarylene sulfide resin composition (A) of the present invention may be blended with other resins other than the components (A) and (B) as long as the effects of the present invention are not impaired. There are no particular limitations on the resins that can be blended, but specific examples include polyamide resins, polyester resins such as polyethylene terephthalate, polybutylene terephthalate, polycyclohexyldimethylene terephthalate, and polynaphthalene terephthalate, polyethylene, polypropylene, polytetrafluoroethylene, polyether ester elastomers, polyether amide elastomers, polyamide imides, polyacetals, polyimides, polyether imides, siloxane copolymerized polyimides, polyether sulfones, polysulfone resins, polyarylsulfone resins, polyketone resins, polyarylate resins, liquid crystal polymers, polyether ketone resins, polythioether ketone resins, polyether ether ketone resins, polyamide imide resins, and tetrafluoroethylene resins.

Furthermore, the polyarylene sulfide resin composition of the present invention may contain other components within the scope of the present invention, such as antioxidants and heat stabilizers (hydroquinone-based) other than those mentioned above, weathering agents (resorcinol-based, salicylate-based, benzotriazole-based, benzophenone-based, hindered amine-based, etc.), release agents and lubricants (montanic acid and its metal salts, its esters, its half esters, stearyl alcohol, stearamide, bisurea, polyethylene wax, etc.), pigments (cadmium sulfide, phthalocyanine, coloring carbon black, etc.), dyes (nigrosine, etc.), crystal nucleating agents (talc, silica, kaolin, clay, etc.), plasticizers (octyl p-oxybenzoate, N-butylbenzenesulfonamide, etc.), antistatic agents (alkyl sulfate-type anionic antistatic agents, quaternary ammonium salt-type cationic antistatic agents, It is possible to add ordinary additives such as antistatic agents, nonionic antistatic agents such as polyoxyethylene sorbitan monostearate, betaine-based amphoteric antistatic agents, etc.), flame retardants (for example, red phosphorus, phosphate esters, melamine cyanurate, hydroxides such as magnesium hydroxide and aluminum hydroxide, ammonium polyphosphate, brominated polystyrene, brominated polyphenylene ether, brominated polycarbonate, brominated epoxy resins, or combinations of these brominated flame retardants with antimony trioxide, etc.), heat stabilizers, lubricants such as calcium stearate, aluminum stearate, and lithium stearate, strength improvers such as bisphenol epoxy resins such as bisphenol A type, novolac phenol type epoxy resins, and cresol novolac type epoxy resins, ultraviolet inhibitors, colorants, flame retardants, and foaming agents.

Manufacturing method of resin composition Regarding the manufacturing method of the polyarylene sulfide resin composition of the present invention, there is no particular restriction on the mixing order of the raw materials, and any method may be used, such as a method of blending all raw materials and then melt-kneading them by the above method, a method of blending a part of the raw materials and then melt-kneading them by the above method, and then blending and melt-kneading the remaining raw materials, or a method of blending a part of the raw materials and then using a side feeder to mix the remaining raw materials during melt-kneading by a twin-screw extruder. In addition, as for the small amount of additive components, it is of course possible to knead other components by the above method or the like, pelletize them, and then add them before molding to be subjected to molding.

Representative examples of the method for producing the polyarylene sulfide resin composition of the present invention include a method in which raw materials are supplied to a commonly known melt kneader such as a single-screw or twin-screw extruder, a Banbury mixer, a kneader, and a mixing roll, and melt kneaded at a processing temperature of the melting peak temperature of (A) PAS + 5 to 100 ° C. In this case, it is preferable to use a twin-screw extruder to make the shear force relatively strong. Specifically, a twin-screw extruder having an L/D (L: screw length, D: screw diameter) of 20 or more, preferably 30 or more, and having two or more kneading sections, preferably three or more, is used, and the screw rotation speed is 150 to 1000 rpm, preferably 300 to 1000 rpm, and kneading is performed so that the resin temperature during mixing is the melting peak temperature of (A) PAS + 10 to 70 ° C. The upper limit of L/D is not particularly limited, but 60 or less is preferable from the viewpoint of economic efficiency. There is also no particular upper limit on the number of kneading locations, but from the perspective of productivity, it is preferable for the number to be 10 or less.

The PAS resin composition obtained in this manner can be used for various molding processes such as injection molding, extrusion molding, blow molding, and transfer molding, but is particularly suitable for injection molding.

The polyarylene sulfide resin composition of the present invention has excellent heat resistance and impact resistance, and can therefore be used in electrical and electronic equipment, precision machinery equipment, water-related parts, office equipment, automotive and vehicle parts, building materials, packaging materials, furniture, and daily necessities.

In particular, it can be used favorably for piping parts used in places where high water pressures equivalent to direct water pressure or high water pressures due to water hammers are applied, such as parts related to residential plumbing equipment, toilets, water heaters, baths, pumps, and water meters. Examples of piping parts include joints, valves, servos, sensors, pipes, and pumps, and it is particularly suitable for use in residential piping parts and water heater parts.

The liquid flowing through the piping parts can be water or an antifreeze containing alcohols, glycols, glycerin, etc., and there are no particular limitations on the type or concentration, so it can also be used in parts through which high-temperature liquids flow.

It can also be used in plumbing components such as water faucet parts and mixer taps, which have low water pressure loads, and water meter parts, which have high water pressure loads but do not allow high-temperature water to flow.

Other applications for molded articles made from the PPS resin composition used in the present invention include electrical and electronic components such as sensors, LED lamps, consumer connectors, sockets, resistors, relay cases, switches, coil bobbins, capacitors, variable capacitor cases, oscillators, various terminal boards, transformers, plugs, printed circuit boards, tuners, speakers, microphones, headphones, small motors, magnetic head bases, semiconductors, liquid crystal, FDD carriages, FDD chassis, motor brush holders, parabolic antennas, and computer-related components; VTR components, television components, irons, hair dryers, rice cooker components, microwave oven components, audio components, audio equipment components such as audio laser discs (registered trademarks) and compact discs, lighting components, refrigerator components, air conditioner components, typewriter components, and word processor components, as well as household and office electrical appliance components. Others include office computer parts, telephone parts, facsimile parts, copier parts, cleaning tools, motor parts, lighters, typewriters and other machine parts; microscopes, binoculars, cameras, watches and other optical equipment, precision machinery parts; valve alternator terminals, alternator connectors, IC regulators, light dimmer potentiometer bases, exhaust gas valves and other valves, fuel-related, exhaust and intake pipes, air intake nozzle snorkels, intake manifolds, fuel pumps, engine coolant joints, carburetor main bodies, carburetor spacers, exhaust gas sensors, coolant sensors, oil temperature sensors, throttle position sensors, crankshaft position sensors, air Examples of applications include automobile and vehicle-related parts such as flow meters, brake pad wear sensors, thermostat bases for air conditioners, heating hot air flow control valves, brush holders for radiator motors, water pump impellers, turbine vanes, wiper motor-related parts, distributors, starter switches, starter relays, transmission wire harnesses, windshield washer nozzles, air conditioner panel switch boards, coils for fuel-related electromagnetic valves, fuse connectors, horn terminals, electrical component insulation plates, step motor rotors, lamp sockets, lamp reflectors, lamp housings, brake pistons, solenoid bobbins, engine oil filters, ignition device cases, vehicle speed sensors, and cable liners.

The present invention will be explained in more detail below with reference to examples, but the present invention is not limited to the description of these examples.

[Evaluation method of PAS produced in Reference Example]
(1) Melt flow rate (MFR)
The measurement was performed according to ASTM D 1238-70 at a temperature of 315° C. and a load of 5000 g. A melt indexer manufactured by Toyo Seiki Seisakusho (length 8.00 mm, orifice with a hole diameter of 2.095 mm, sample amount 7 g, preheat time from sample loading to start of measurement 5 minutes, load 5000 g) was used, and the measurement was performed under conditions of 315° C.

(2) Dispersity (Mw/Mn)
The dispersity (Mw/Mn) expressed as weight average molecular weight/number average molecular weight was calculated in terms of polystyrene by gel permeation chromatography (GPC), which is a type of size exclusion chromatography (SEC). The conditions are as follows:
Equipment: Senshu Science SSC-7110
Column name: Shodex UT806M x 2
Eluent: 1-chloronaphthalene Detector: Differential refractive index detector Column temperature: 210°C
Pre-thermostat temperature: 250°C
Pump thermostatic chamber temperature: 50°C
Detector temperature: 210°C
Flow rate: 1.0mL/min
Sample injection volume: 300 μL.

(3) Cooling Crystallization Temperature Using a differential scanning calorimeter DSCQ200 manufactured by TA Instruments, the temperature was raised from 50° C. to 340° C. at a heating rate of 20° C./min under a nitrogen flow, the temperature was held for 1 minute, and then the temperature was lowered from 340° C. to 100° C. at a cooling rate of 20° C./min to measure the cooling crystallization temperature (Tmc) of the PAS.

(4) Preparation of amorphous film The preparation conditions for the amorphous film are as follows. PAS and a spacer (aluminum plate of about 0.3 mm) were sandwiched between polyimide films. The polyimide film was sandwiched between a press mold heated to the melting point of PAS or higher, and pressure was applied for 1 minute. After applying pressure for 1 minute to retain the PAS, the polyimide film was removed and immersed in prepared water for rapid cooling to obtain an amorphous film.

(5) Carboxyl Group Content The carboxyl group content of the PAS was estimated by measuring the amorphous film of the PAS with FT-IR (IR-810 infrared spectrophotometer manufactured by JASCO Corporation) and comparing the absorption at around 1,730 cm ⁻¹ due to the carboxyl group with the absorption at around 1,900 cm ⁻¹ due to the benzene ring.

(6) Ash Content 5.0 g of PAS was weighed into a crucible and fired at 550° C. for 6 hours in a TMF-5 electric furnace manufactured by Thomas Scientific Instruments, Inc. The mixture was then removed from a desiccator containing a desiccant and cooled. The weight of the recovered residue was then weighed, and the ash content was calculated as a percentage based on the ratio of the weight of the residue to the weight of the PAS before firing.

(7) Amount of Chloroform Extractable Component 10 g of PAS was weighed out and subjected to Soxhlet extraction with 100 g of chloroform for 3 hours. The weight of the component obtained after distilling off the chloroform from the extract was measured, and the weight was calculated as a percentage of the weight of the charged polymer (wt %).

(A) PAS
[Reference Example 1] Preparation of PAS: (A)-1 A 70L reaction vessel equipped with a stirrer, a bottom plug valve, a distillation apparatus, a distillate receiving tank, and an alkali trap for recovering hydrogen sulfide through an air stream was charged with 11.68 kg (100 moles as sodium hydrosulfide) of 48% by weight aqueous sodium hydrosulfide solution, 4.05 kg (101 moles) of sodium hydroxide, 2.01 kg (24.5 moles) of sodium acetate, 21.11 kg of N-methyl-2-pyrrolidone (NMP), and 6.85 kg of water, and dehydration was performed by heating to 225°C over 2.5 hours while stirring and passing nitrogen at normal pressure. When 12.92 kg of the distillate obtained by dehydration was titrated, 1.94 moles of hydrogen sulfide were scattered, and the molar amount of the sulfidizing agent in the reaction vessel at the end of dehydration was 98.0 moles. After completion of the dehydration, the mixture was cooled to 200° C., and 14.48 kg (98.5 mol) of p-dichlorobenzene (p-DCB), 71 g (0.39 mol) of 1,2,4-trichlorobenzene, and 7.31 kg of NMP were added, and the reaction vessel was closed and heated to 276° C. with stirring, and the reaction was carried out by maintaining the temperature at 276° C. for 123 minutes. After completion of the reaction, the bottom plug valve of the reaction vessel was opened, and the reaction liquid was flushed into another vessel connected to the lower part of the reaction vessel, and then the entire amount of NMP was evaporated over 3 hours with stirring at 265° C.

The resulting recovered material was reslurried in water and filtered to remove by-product salts, then washed with an aqueous solution of acetic acid until the ash content in the polymer was 0.2% by weight or less. The resulting wet cake was rinsed with water and then dried at 150°C for 3 hours under a nitrogen stream to obtain 10 kg of dried PAS-1. This PAS production was repeated 10 times to prepare 100 kg of dried PAS-1.

Next, 500 kg of NMP was charged into a 1.0 ^m3 reaction vessel equipped with a stirrer and a bottom plug valve, and 100 kg of the dried PAS-1 obtained above was added and stirred at 30°C for 20 minutes. The slurry was then pumped into a centrifuge equipped with a filter cloth to perform centrifugal filtration. After completion of filtration, the cake on the filter cloth was subsequently rinsed with 200 kg of NMP, and centrifugal filtration was performed until the liquid was drained. The obtained wet cake was dried at 220°C for 3 hours under a nitrogen stream of 300 L/min to obtain PAS: (A)-1. The polymer properties of the obtained PAS: (A)-1 were as shown in Tables 1 and 2.

Reference Example 2 Preparation of PAS: (A)-2 In Reference Example 1, the operation was terminated when dry PAS-1 was obtained, and polymerization and washing were carried out in the same manner as in Reference Example 1, except that washing with an organic solvent (NMP) was not carried out. The polymer properties of the obtained PAS: (A)-2 were as shown in Tables 1 and 2.

Reference Example 3: Preparation of PAS: (A)'-1 A 70L reaction vessel equipped with a stirrer, a bottom plug valve, a distillation apparatus, a distillate receiving tank, and an alkali trap for recovering hydrogen sulfide through an air stream was charged with 11.68 kg (100 moles as sodium hydrosulfide) of 48% by weight aqueous sodium hydrosulfide solution, 4.15 kg (104 moles) of sodium hydroxide, 2.30 kg (28.0 moles) of sodium acetate, 16.36 kg of N-methyl-2-pyrrolidone (NMP), and 7.30 kg of water, and dehydration was performed by heating to 225°C over 2.5 hours while stirring and passing nitrogen through at normal pressure. Titration analysis of 13.37 kg of the distillate obtained by dehydration revealed that 1.60 moles of hydrogen sulfide had been scattered, and the molar amount of the sulfidizing agent in the reaction vessel at the end of dehydration was 98.4 moles. After completion of the dehydration, the mixture was cooled to 200°C, and 14.80 kg (100.7 mol) of p-dichlorobenzene (p-DCB), 53 g (0.29 mol) of 1,2,4-trichlorobenzene, and 12.94 kg of NMP were added, and the reaction vessel was closed, and the temperature was raised to 270°C with stirring, and the mixture was maintained at 270°C for 170 minutes to cause the reaction.

After the reaction was completed, the reaction vessel was cooled to below 200°C, the bottom plug valve of the reaction vessel was opened, and the liquid was transferred to another vessel (previously charged with 37.67 kg of NMP) connected to the bottom of the reaction vessel.

The resulting slurry was filtered through a TYLER standard 80 mesh (177 μm mesh) screen filter to recover the cake, which was washed again with NMP at 95°C and then with water at 70°C to remove by-product salts, and then dried at 150°C for 3 hours under a nitrogen stream to obtain 8.8 kg of PAS: (A)'-1. The polymer properties of the resulting PAS: (A)'-1 were as shown in Tables 1 and 2.

Reference Example 4: Preparation of PAS: (A)'-2 A 70L reaction vessel equipped with a stirrer, a bottom plug valve, a distillation apparatus, a distillate receiving tank, and an alkali trap for recovering hydrogen sulfide through an air stream was charged with 11.68 kg of 48% by weight aqueous sodium hydrosulfide solution (100 moles as sodium hydrosulfide), 4.05 kg (101 moles) of sodium hydroxide, 1.55 kg (18.9 moles) of sodium acetate, 21.11 kg of N-methyl-2-pyrrolidone (NMP), and 6.28 kg of water, and dehydration was performed by heating to 225°C over 2.5 hours while stirring and passing nitrogen through at normal pressure. Titration analysis of 12.35 kg of the distillate obtained by dehydration revealed that 1.94 moles of hydrogen sulfide had been scattered, and the molar amount of the sulfidizing agent in the reaction vessel at the end of dehydration was 98.0 moles. After completion of the dehydration, the mixture was cooled to 200° C., and 14.78 kg (100.5 mol) of p-dichlorobenzene (p-DCB) and 7.46 kg of NMP were added, and the reaction vessel was closed and heated to 276° C. with stirring, and the reaction was carried out by maintaining the temperature at 276° C. for 75 minutes. After completion of the reaction, the bottom plug valve of the reaction vessel was opened, and the reaction liquid was flushed into another vessel connected to the lower part of the reaction vessel, and then the entire amount of NMP was evaporated over 3 hours with stirring at 265° C.

The resulting recovered material was reslurried in water and filtered to remove by-product salts, then washed with an aqueous solution of acetic acid until the ash content in the polymer was 0.2% by weight or less. The resulting wet cake was rinsed with water and then dried at 150°C for 3 hours under a nitrogen stream to obtain 10 kg of dried PAS-2. This PAS production was repeated 10 times to prepare 100 kg of dried PAS-2.

Next, 500 kg of NMP was charged into a 1.0 ^m3 reaction vessel equipped with a stirrer and a bottom plug valve, and 100 kg of the dried PAS-2 obtained above was added and stirred at 30°C for 20 minutes. The slurry was then pumped into a centrifuge equipped with a filter cloth to perform centrifugal filtration. After completion of filtration, the cake on the filter cloth was subsequently rinsed with 200 kg of NMP, and centrifugal filtration was performed until the liquid was drained. The obtained wet cake was dried at 220°C for 3 hours under a nitrogen stream of 300 L/min to obtain dried PAS-3.

The dried PAS-3 obtained above was then subjected to thermal oxidation treatment with stirring at an oxygen concentration of 11% at 220°C for 12 hours, after drying, to obtain PAS: (A)'-2. The polymer properties of the obtained PAS: (A)'-2 were as shown in Tables 1 and 2.

Reference Example 5: Preparation of PAS: (A)'-3 A 70L reaction vessel equipped with a stirrer, a bottom plug valve, a distillation apparatus, a distillate receiving tank, and an alkali trap for recovering hydrogen sulfide through an air stream was charged with 11.68 kg of 48% by weight sodium hydrosulfide aqueous solution (100 moles as sodium hydrosulfide), 4.15 kg (104 moles) of sodium hydroxide, 3.69 kg (45.0 moles) of sodium acetate, 16.36 kg of N-methyl-2-pyrrolidone (NMP), and 9.00 kg of water, and dehydration was performed by heating to 225°C over 2.5 hours while stirring and passing nitrogen through at normal pressure. Titration analysis of 15.08 kg of the distillate obtained by dehydration revealed that 2.13 moles of hydrogen sulfide had been scattered, and the molar amount of the sulfidizing agent in the reaction vessel at the end of dehydration was 97.9 moles. After completion of the dehydration, the contents were cooled to 200° C., and 14.74 kg (100.3 mol) of p-dichlorobenzene (p-DCB) and 13.11 kg of NMP were added, and the reaction vessel was closed and heated to 270° C. with stirring, and the reaction was carried out by holding at 270° C. for 120 minutes. Note that 10 minutes after the temperature reached 270° C., a total of 1.44 kg of water was added to the reaction vessel by pump.

After the reaction was completed, the reaction vessel was cooled to below 200°C, the bottom plug valve of the reaction vessel was opened, and the liquid was transferred to another vessel (previously charged with 37.50 kg of NMP) connected to the bottom of the reaction vessel.

The resulting slurry was filtered through a TYLER standard 80 mesh (177 μm mesh) screen filter to recover the cake, which was washed again with NMP at 95°C and then with water at 70°C to remove by-product salts. The resulting wet cake was then reslurried again with water and washed with an aqueous acetic acid solution until the ash content in the polymer was 0.1% by weight or less. The resulting wet cake was rinsed with water and then dried at 150°C for 3 hours under a nitrogen stream to obtain 9.1 kg of PAS: (A)'-3. The polymer properties of the resulting PAS: (A)'-3 were as shown in Tables 1 and 2.

(B) Thermoplastic elastomer (B1): Bondfast E (ethylene/glycidyl methacrylate copolymer) manufactured by Sumitomo Chemical Co., Ltd.
(B2)-1: TAFMER A0550S (ethylene/1-butene copolymer) manufactured by Mitsui Chemicals, Inc.
(B2)-2: ENGAGE 8842 (ethylene/1-octene copolymer) manufactured by The Dow Chemical Company
(B)-1: Tuftec MP-10 (hydrogenated product of amino group-modified styrene/butadiene copolymer) manufactured by Asahi Kasei Corporation.

(C) Organic silane coupling agent having a functional group (C)-1: KBM-303 (2-(3,4-epoxycyclohexyl)ethyltrimethoxysilane) manufactured by Shin-Etsu Chemical Co., Ltd.
(C)-2: KBE-903 (3-aminopropyltriethoxysilane) manufactured by Shin-Etsu Chemical Co., Ltd.
(C)-3: KBE-9007N (3-isocyanatepropyltriethoxysilane) manufactured by Shin-Etsu Chemical Co., Ltd.

[Evaluation method of PAS resin composition produced in the examples]
(1) Spiral flow length Using a spiral flow mold of 1 mm thickness (1 mmt), molding was performed under the conditions of cylinder temperature 320°C, mold temperature 140°C, injection speed 230 mm/sec, injection pressure 98 MPa, injection time 5 sec, and cooling time 15 sec, and the spiral flow length (unit: mm) was measured (injection molding machine used: SE-30D manufactured by Sumitomo Heavy Industries, Ltd.). The larger this value, the better the flowability.

(2) Burr Length Using an injection molding machine (SE30D) manufactured by Sumitomo Heavy Industries, Ltd., (a) width 5 mm × length 20 mm × thickness 1,000 μm, (b) width 5 mm × length 20 mm × thickness 700 μm, (c) width 5 mm × length 20 mm × thickness 500 μm, (d) width 5 mm × length 20 mm × thickness 300 μm, (e) width 5 mm × length 20 mm × thickness 100 μm, (f) width 5 mm × length 20 mm A disk-shaped mold having eight projections, (g) width 5 mm x length 20 mm x thickness 50 μm, (h) width 5 mm x length 20 mm x thickness 10 μm, was used for injection molding at a molding temperature of 320° C. and a mold temperature of 130° C., and the filling length of the projection (h) when the projection (b) was filled to the tip was measured, and this was taken as the burr length (mm). The gate position was the center of the disk. A short burr length indicates good low burr properties.

(3) Continuous moldability Using the PAS resin composition of each Example and Comparative Example, a thin plate-shaped molded product was produced by injection molding, and the amount of mold contamination and mold appearance after molding were evaluated. That is, the size of the molded product was a maximum length of 55 mm, a width of 20 mm, a thickness of 2 mm, a gate size of 2 mm and a thickness of 1 mm (side gate), and the size of the gas vent part was a maximum length of 20 mm, a width of 10 mm, and a depth of 5 μm. Continuous molding was performed using SE-30D manufactured by Sumitomo Heavy Industries, Ltd. Specifically, the cylinder temperature was set to 305° C., the mold temperature to 130° C., the injection speed to 100 mm/s, and the injection pressure was set within 50 to 80 MPa so that the filling time for each resin composition was 0.4 seconds, and further, continuous molding was performed with a holding pressure of 25 MPa, a holding pressure speed of 30 mm/s, and a holding pressure time of 3 seconds. Continuity was evaluated as "excellent" (○) when the sprue and runner of the molded product were not left behind on the nozzle side and the molded product was released from the cavity portion, allowing for continuous molding of 200 shots or more, "slightly poor" (△) when 5 to 199 shots were possible, and "poor" (×) when less than 5 shots were possible. The outline of the molded product of the evaluation mold used is shown in Figure 1.

(4) Mold release force Using the PAS resin composition of each Example and Comparative Example, a small box-shaped molded product having an opening on one side was prepared by injection molding, and the load applied to the ejector pin when the molded product was ejected from the mold was measured. That is, molding was performed using an SE-30D manufactured by Sumitomo Heavy Industries, Ltd., with an evaluation mold having a molded product size of width 35 mm, length 35 mm, height 25 mm, side thickness 1.5 mm x bottom thickness 2.0 mm. Molding was performed under the conditions of a cylinder temperature of 320°C, a mold temperature of 130°C, and an injection speed of 100 mm/s. The load applied to the ejector pin when the molded product was ejected from the mold was taken as the mold release force, and the smaller the mold release force, the better the mold release property.

(5) Tensile Strain The PPS resin composition pellets of the present invention were dried at 130°C for 3 hours using a hot air dryer, and then fed to an injection molding machine (SE-50D) manufactured by Sumitomo Heavy Industries, Ltd., set at a cylinder temperature of 320°C and a mold temperature of 145°C, and injection molding was performed using a mold having a type A1 test piece shape as specified in ISO 20753 (2008) under conditions in which the average speed of the molten resin passing through the cross-sectional area of the central parallel part was 400±50 mm/s to obtain a test piece. The test piece was conditioned for 16 hours under conditions of 23°C and 50% relative humidity, and then measured in accordance with ISO527-1,-2 (2012) under conditions of 23°C, 50% relative humidity, gripper distance: 114 mm, and test speed: 50 mm/s, and the breaking strain was taken as the tensile strain (%) of the non-weld part.

(6) Flexural modulus The PPS resin composition pellets of the present invention were dried at 130°C for 3 hours using a hot air dryer, and then fed to a Sumitomo Heavy Industries injection molding machine (SE-50D) set at a cylinder temperature of 320°C and a mold temperature of 145°C. Using a mold having a type A1 test piece shape as specified in ISO 20753 (2008), injection molding was performed under conditions in which the average speed of the molten resin passing through the cross-sectional area of the central parallel part was 400±50 mm/s to obtain a test piece. The central parallel part of this test piece was cut out to obtain a type B2 test piece. This test piece was conditioned for 16 hours under conditions of 23°C and 50% relative humidity, and then measured in accordance with the ISO 178 (2010) method under conditions of 23°C, 50% relative humidity, span 64 mm, and test speed: 2 mm/s.

(7) Notched Charpy Impact Strength Using pellets of the PPS resin composition of the present invention, 1A type dumbbell specimens (4.0 mm thick) in accordance with ISO 3167 were injection molded at a cylinder temperature of 320°C and a mold temperature of 140°C, and test specimens (4.0 mm wide, notched) were prepared by cutting out 80 mm from the center and machining a V-notch, and the notched Charpy impact strength (KJ/ ^m2 ) was measured in accordance with ISO 179 under a temperature condition of 23°C.

[Examples 1 to 10 and Comparative Examples 1 to 6]
Using a 26 mm diameter twin-screw extruder (TEM-26SS L/D=64.6 manufactured by Toshiba Machine Co., Ltd.) with a cylinder temperature set at 310° C., (A) PAS, (B) thermoplastic elastomer, and (C) organic silane coupling agent having a functional group were dry-blended in the weight ratios shown in Tables 1 and 2, added from the extruder raw material supply port to make it in a molten state, and melt-kneaded under conditions of s/r rotation speed of 300 rpm and total discharge rate of 40 kg/hour to obtain resin composition pellets. The obtained resin composition pellets were subjected to the above-mentioned injection molding to obtain various molded products, and then the tensile strain, flexural modulus, and notched Charpy impact strength were evaluated. In addition, the spiral flow length, burr length, and continuous moldability were evaluated by the above-mentioned method. The results were as shown in Tables 1 and 2.

[Examples 1 to 10]
In Examples 1 to 10 shown in Table 1, the melt flow rate measured under conditions of 315°C and a load of 5000g in accordance with ASTM D 1238-70 is 50g/10 minutes or more and 300g/10 minutes or less, the crystallization temperature measured at a temperature drop rate of 20°C/min using a differential scanning calorimeter (DSC) is 200°C or more and 230°C or less, the carboxyl group content is 30μmol/g or more and 100μmol/g or less, and the dispersity expressed by weight average molecular weight/number average molecular weight is 6.0 or more and 15.0 or less. By using PAS, which is characterized by the above, the spiral flow length, tensile strain, and Charpy impact strength (notched) are good, and the moldability is excellent with low flash and continuous moldability.

Comparative Example 1
Comparative Example 1 shown in Table 2 had an MFR of 50 or less and a cooling crystallization temperature of 200° C. or less, and was therefore inferior in low flash properties, continuous moldability and spiral flow length.

Comparative Example 2
In Comparative Example 2 shown in Table 1, the MFR is equivalent to that of Example 1, but the carboxyl group content is 30 μmol/g or less and the dispersity expressed by weight average molecular weight/number average molecular weight is 6.0 or less, so that the low flash property is inferior and the tensile strain and Charpy impact strength (notched) are also unfavorable.

[Comparative Examples 3 and 4]
Comparative Examples 3 and 4 shown in Table 1 had the same MFR as Example 1, but had a carboxyl group content of 30 μmol/g or less and a dispersity expressed by weight average molecular weight/number average molecular weight of 6.0 or less, and therefore were inferior in low flash properties and continuous moldability.

[Comparative Examples 5 and 6]
Comparative Examples 6 and 7 shown in Table 1 correspond to Examples 2 and 10 in terms of the amount of elastomer, respectively. However, the carboxyl group content was 30 μmol/g or less, and the dispersity expressed as weight average molecular weight/number average molecular weight was 6.0 or less. Therefore, the low flash property and continuous moldability were inferior to the corresponding ones.

The polyarylene sulfide resin composition of the present invention has excellent impact resistance, low flash during molding, fluidity, and continuous moldability, and is therefore suitable for use in electrical and electronic equipment, precision machinery equipment, water-related parts, office equipment, automobile and vehicle-related parts, building materials, packaging materials, furniture, and daily necessities, particularly water-related parts and automobile applications.

G Gate

Claims (7)

A polyarylene sulfide resin composition comprising 100 parts by weight of (A) polyarylene sulfide and 1 to 50 parts by weight of (B) thermoplastic elastomer, characterized in that the polyarylene sulfide (A) has a melt flow rate of 50 g/10 min to 300 g/10 min measured under conditions of 315°C and a load of 5000 g in accordance with ASTM D 1238-70, a crystallization temperature measured at a cooling rate of 20°C/min using a differential scanning calorimeter (DSC) of 200°C to 230°C, a carboxyl group content of 30 μmol/g to 100 μmol/g, and a polydispersity expressed as weight average molecular weight/number average molecular weight of 6.0 to 15.0. The polyarylene sulfide resin composition according to claim 1, further comprising 0.05 to 5 parts by weight of (C) an organic silane coupling agent having at least one functional group selected from the group consisting of an epoxy group, an amino group, and an isocyanate group, per 100 parts by weight of the polyarylene sulfide (A). The polyarylene sulfide resin composition according to claim 1 or 2, characterized in that the polyarylene sulfide (A) has a chloroform extractable component content of 0.5% by weight or more and 2.0% by weight or less. The polyarylene sulfide resin composition according to claim 1 or 2, characterized in that the (B) thermoplastic elastomer is (B1) a glycidyl group-containing copolymer having as copolymerization components an α-olefin and a glycidyl ester of an α,β-unsaturated acid, and (B2) an ethylene-α-olefin copolymer having as copolymerization components ethylene and an α-olefin having 3 to 20 carbon atoms. The polyarylene sulfide resin composition according to claim 1 or 2, characterized in that the (A) polyarylene sulfide has a branched/crosslinked structure derived from a polyhalogenated aromatic compound having three or more halogen substituents per molecule. A molded article made of the polyarylene sulfide resin composition according to claim 1 or 2. The molded product according to claim 6, characterized in that the molded product is a plumbing part for use in a water supply system selected from the group consisting of residential plumbing equipment parts, toilet parts, water heater parts, bath parts, pump parts, and water meter parts.

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