JPH11166088A - Production of rubber-modified styrene-based resin composition - Google Patents

Abstract

PROBLEM TO BE SOLVED: To produce a rubber-modified styrene-based resin composition having a high impact resistance and a high fluidity. SOLUTION: When the rubber-modified styrene-based resin composition is produced by using a continuous polymerization equipment comprising two or more units of continuously connected reactional vessels, a polymerization stock solution having the concentration of an organic peroxide [I] (wt. ppm); the concentration of an aromatic solvent [E] (wt.%) and the concentration of a molecular weight modifier [S] (wt. ppm) satisfying the formula 9<=15[I]<1/2> /[E]+[S]<1/2> <=21 is used and a dispersed phase of a rubber at 20-35% degree of conversion of styrene in the first stirred vessel which is a complete mixing type reactional vessel and the degree of conversion is raised to 50-95% in the subsequent reactional vessel to separate the residual monomers and solvent. Thereby, dispersed rubber particles having 1-4 μm volume average particle diameter and the value of the ratio of a 10% value in a cumulative distribution of the particle diameter based on the volume to a 90% value thereof within the range of 3-20 are formed.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a method for producing a rubber-modified styrenic resin composition. Specifically, the present invention relates to a method for producing a rubber-modified styrenic resin composition having high fluidity and improved impact resistance by polymerization under specific polymerization conditions.

[0002]

2. Description of the Related Art Polystyrene is a resin that is transparent and hard, has excellent dimensional stability and electrical insulation properties, but is vulnerable to impact. To remedy this drawback, impact-resistant styrenic resins to which a rubbery polymer has been added have been developed. As the impact-resistant styrenic resin, those obtained by blending a rubbery polymer with polystyrene are also known, but simply blending the rubbery polymer has a small effect of improving the impact resistance.

[0003] Usually, a rubber-modified styrene having a good impact resistance is obtained by adding a rubber-like polymer during the polymerization of styrene and grafting styrene to the rubber-like polymer by a graft reaction to thereby easily disperse the rubber-like polymer. A base resin composition is manufactured.

It is known that the physical properties of the rubber-modified styrenic resin composition produced in this manner are greatly affected by the size and structure of the rubbery polymer particles. It has been studied to synthesize a rubber-modified styrenic resin composition having good physical properties by controlling the morphology of the particles.

At present, polymerization methods such as bulk polymerization method, solution polymerization method, suspension polymerization method, bulk-suspension polymerization method, emulsion polymerization method and the like are industrially used as methods for producing such impact-resistant polystyrene resins. It has been implemented.

[0006] Among these polymerization methods, the continuous bulk polymerization method is widely used with the expansion of the production scale because a large quantity of products having uniform physical properties can be obtained at low cost.

[0007] In the continuous bulk polymerization method, a rubbery polymer is used as a modifier in the production of impact-resistant styrenic resin. Usually, these rubbery polymers are broken up into pieces by a pulverizer to form styrene monomers. And then dissolved by adding additives such as a polymerization initiator, a molecular weight regulator, and an antioxidant, and polymerizing.The rubber-like polymer containing polystyrene by grafting styrene onto the double bond of the rubber-like polymer. A styrene resin having good impact resistance in which particles are dispersed is manufactured.

[0008] The impact-resistant styrene resin produced in this manner is excellent in the balance between impact resistance and rigidity, so that rubber-modified styrene resin is increasingly used in place of the ABS resin. It is also used in many industrial parts, including home appliances, office automation equipment, and automotive parts. For example, it has come to be used for molded articles having a large and more complicated shape formed by an injection molding method and having a small thickness. Recently, a resin material having high fluidity has been desired in order to improve the moldability.

However, the more the rubbery polymer contained in the rubber-modified styrenic resin composition is effective in improving the impact resistance, the more effective it is, but there is a problem that the flowability is reduced.

For this purpose, as a method for improving the fluidity, a method of using a large amount of a molecular weight modifier (chain transfer agent) to reduce the molecular weight of the matrix portion is known, but this method has a problem that the impact strength is reduced. is there.

In order to improve impact strength, US Pat.
22 and JP-A-63-112846 disclose a rubber-modified styrenic resin composition having rubbery polymer particles of a single occlusion structure formed using a styrene-butadiene copolymer rubber, and a small amount of rubber having a salami structure. There has been proposed a method of blending an ordinary rubber-modified styrenic resin composition having polymer particles. With these methods, the impact strength is improved, but the production process is complicated and the physical properties are not sufficient.

Japanese Unexamined Patent Publication (Kokai) No. 52-86444 discloses an impact-resistant polystyrene (HIPS) using a polybutadiene rubber having a cis-1,4 bond ratio of 90 mol% or more in a chain butadiene unit as a rubbery polymer. Japanese Patent Publication No. 55-30525 discloses a method for increasing the gel content in a resin by using an organic peroxide and using a specific rubbery polymer. In any case, the fluidity decreases.

JP-A-60-130613 and JP-A-60-130614 disclose a resin composition in which a specific rubbery polymer is used and the particle size and particle size distribution of the dispersed rubbery polymer particles are specified. However, there is no disclosure of a technique for producing a rubber-modified styrenic resin composition having a high impact strength by improving the fluidity of a product.

Japanese Patent Publication No. 6-99531 discloses that
There is disclosed a method of producing a styrene-based resin having high impact by polymerizing styrene by specifying a quantitative ratio of an organic peroxide and a molecular weight modifier (chain transfer agent). Styrene-based resins can be produced, but those having high fluidity cannot be obtained.

[0015]

Generally, in the radical polymerization of a styrene monomer, the polymerization rate is one half of the initiator concentration.
It is known to be proportional to the power. However, if a molecular weight adjusting agent (chain transfer agent) for reducing the molecular weight of the matrix portion is added in order to increase the fluidity of the resin, this relationship will not hold. On the other hand, it is known that when a mercaptan compound as a molecular weight modifier used as a chain transfer agent is used together with an organic peroxide, the effect of reducing the particle size of rubber-like polymer particles is reduced.

Further, there is a problem that the particle size distribution becomes very wide in proportion to the amount of use of the organic peroxide alone. In any case, the relationship between the concentration of the organic peroxide used as the initiator and the concentration of the chain transfer agent is hardly elucidated, and furthermore, the relationship between these quantitative ratio relationships and the physical properties of the obtained resin is completely unknown. Not.

For example, there is a demand for a method for producing a rubber-modified styrene resin which is suitable as a resin material for a large-sized, thin-walled and complicated-shaped product formed by injection molding. An object of the present invention is to provide a method for producing a rubber-modified styrenic resin composition having high fluidity during molding and having high impact strength and an excellent balance of physical properties.

[0018]

Means for Solving the Problems The present inventors have conducted intensive studies in order to solve the above problems, and have examined in detail the effects of various factors relating to polymerization on the physical properties. Even if the molecular weight is reduced to grasp the relationship with the concentration and improve the fluidity, the graft ratio of styrene to the rubbery polymer is increased to further increase the particle size and particle size distribution of the dispersed rubbery polymer. The rubber-modified styrenic resin composition having a high fluidity and a high impact strength can be obtained by producing the rubber-modified styrenic resin composition by a completely new manufacturing method from the conventional knowledge of controlling The present invention has been completed by finding that the above is achieved.

That is, the present invention uses a continuous polymerization apparatus comprising two or more reaction tanks including at least one complete mixing type reaction tank, wherein the continuous phase is a styrene resin and a dispersed phase by bulk polymerization or solution polymerization. Is a method for producing a rubber-modified styrene-based resin composition comprising a diene-based rubber-like polymer encapsulating a styrene-based resin, comprising a raw material charged into a first complete mixing tank of a polymerization system (hereinafter referred to as a polymerization raw material). Liquid))
(1) When the total weight of the styrene monomer, the aromatic solvent and the diene rubber polymer is 100 parts by weight,
(A) 60 to 85 parts by weight of a styrene monomer (b) 5 to 35 parts by weight of an aromatic solvent, and (c) 25
3 to 20 parts by weight of a diene-based rubbery polymer having a 5% by weight styrene solution viscosity at 30 ° C. of 30 to 90 centipoise, and (2) a styrene-based monomer and (a) an organic peroxide 20-300 wt. ppm, (b) molecular weight regulator 0-350 wt. ppm, and (3) the concentration of organic peroxide [I] (wt.
m), the concentration [E] (wt.%) of the aromatic solvent and the concentration [S] (wt. ppm) of the molecular weight modifier,
[I], [E] and [S] are represented by the following equation [1], 9 ≦ 15 [I] ^1/2 / [E] + [S] ^1/3 ≦ 21... [1] Using a polymerization raw material liquid satisfying the relational expression shown below, a styrene-based monomer was added in an amount of 20 to 35 in a first complete mixing type reaction tank.
% To form a dispersed phase composed of the rubbery polymer, and subsequently increase the conversion of the styrene-based monomer to 50 to 95% in the subsequent reaction tank , and further separate the remaining monomer from the solvent. The volume average diameter of the rubber-like polymer particles as the disperse phase is 1 to 4 μm, and the 10% value (D1) and the 90% value (D2) of the cumulative particle size distribution on a volume basis.
Is a method for producing a rubber-modified styrenic resin composition having a ratio (D1 / D2) of 3 to 20.

In the method of the present invention, first, the amount of the organic peroxide, the amount of the molecular weight modifier (chain transfer agent), and the concentration of the aromatic solvent added to the polymerization system are determined by the relationship represented by the formula [1]. To be held.

Further, the particle size and particle size distribution of the diene rubber-like polymer particles containing the styrene resin are related to the improvement of the balance between the fluidity and the impact strength of the styrene resin composition. In a first complete mixing type reaction vessel, the styrenic monomer is added in an amount of 20 to 35
%.

[0022]

BEST MODE FOR CARRYING OUT THE INVENTION The styrene monomer referred to in the present invention includes side chain alkyl-substituted styrenes such as styrene, α-methylstyrene and α-ethylstyrene, vinyltoluene, vinylxylene, and ot-butyl. Styrene, pt
-Alkyl styrene such as -butylstyrene, halogenated styrenes such as monochlorostyrene, dichlorostyrene, tribromostyrene and tetrabromostyrene, p-hydroxystyrene, o-methoxystyrene and the like. Particularly preferably, styrene monomers such as styrene, α-methylstyrene, and vinyltoluene can be used alone or in combination of two or more.

Also, 25 w
t. % Or less, other radically polymerizable monomers such as methyl methacrylate, acrylic acid, phenylmaleimide, acrylonitrile, acrylamide, maleic anhydride and the like can be used simultaneously.

In the present invention, it is necessary to use an organic peroxide as a polymerization initiator when granulating the rubbery polymer. The amount of the organic peroxide used is 20 per styrene monomer contained in the solution in which the rubbery polymer is dissolved.
~ 300 wt. ppm is preferably used, more preferably 30 to 250 wt. ppm.

When the organic peroxide is 20 wt. When the amount is less than ppm, the effect of improving the impact resistance is small because the graft reaction of the styrene monomer to the rubbery polymer hardly occurs.
300 wt. When used in excess of ppm, the rate of graft reaction of the styrene monomer to the rubbery polymer component can be increased, so that a rubber-modified styrene resin composition having high impact strength can be produced, Is not preferred.

The organic peroxide used in the present invention is not particularly limited as long as it is generally used for the polymerization of styrene monomers. For example, 2,2-bis (t-butylperoxy) butane, 2,2-bis (t
-Butylperoxy) octane, 1,1-bis (t-butylperoxy) -3,3,5-trimethylcyclohexane, 1,1-bis (t-butylperoxy) cyclohexane, 4,4-bis (t Peroxy ketals such as -butylperoxy) valate, di-t-butyl peroxide, t-butylcumyl peroxide, dicumyl peroxide, α, α'-bis (t-butylperoxyisopropyl) benzene, 2 , 5-dimethyl-2,5-di (t
-Butylperoxy) hexane, 2,5-dimethyl-
Dihydrocarbyl peroxides such as 2,5-di (t-butylperoxy) hexine-3, acetyl peroxide, isobutyryl peroxide, octanoyl peroxide, decanoyl peroxide, lauroyl peroxide, 3,5 Diacyl peroxides such as 5-trimethylhexanoyl peroxide, benzoyl peroxide, 2,4-dichlorobenzoyl peroxide, m-toluenyl peroxide, di-isopropylperoxydicarbonate, di-ethylhexylperoxydicarbonate , Di-n-propylperoxydicarbonate, di-myristylperoxydicarbonate, di-ethoxyethylperoxydicarbonate, di-methoxyisopropylperoxydicarbonate, di (3-methyl-3-methoxybutyi) ) Peroxydicarbonate such as peroxydicarbonate, t- butyl peroxy acetate, t- butyl peroxy isobutyrate, t
-Butyl peroxypivalate, t-butyl peroxy neodecanoate, t-butyl peroxy-2-ethyl-hexanoate, t-butyl peroxy-3,5,5
-Trimethylhexanoate, t-butylperoxynourate, t-butylperoxybenzoate, t-butylperoxyisophthalate, 2,5-dimethyl-
Peroxyesters such as 2,5-di (benzoylperoxy) hexane, t-butylperoxyisopropyl carbonate, acetylacetone peroxide, methyl ethyl ketone peroxide, cyclohexanone peroxide, 3,3,5-trimethylcyclohexanone peroxide, methyl Ketone peroxides such as cyclohexanone peroxide, t-butyl hydroperoxide,
Cumene hydroperoxide, di-isopropylbenzene hydroperoxide, 2,5-dimethylhexane-2,
Hydroperoxides such as 5-dihydroperoxide and 1,1,3,3-tetramethyl-butylhydroperoxide are exemplified, and among these, 1,1-bis (t
-Butylperoxy) -3,3,5-trimethylcyclohexane is particularly preferred. These can be used alone or in combination of two or more.

In the present invention, a resin having sufficiently high fluidity can be obtained without using a molecular weight modifier. Generally, the molecular weight modifier is 0 to 350 wt. pp
m, preferably from 0 to 250 wt. ppm used. The molecular weight modifier is not particularly limited as long as it is generally used in a styrene-based polymerization reaction, and a mercaptan compound or α-methylstyrene dimer is used. Among them, an alkyl mercaptan compound is preferable as the mercaptan compound.

In the present invention, the aromatic solvent is used in an amount of from 5 to 35 parts by weight, preferably from 15 to 35 parts by weight, based on 100 parts by weight of the polymerization raw material liquid.
It is characterized by using 35 parts by weight. If the amount of the aromatic solvent is less than 5 parts by weight, the fluidity is reduced. If the amount is more than 35% by weight, the effect of using an organic peroxide is reduced and the impact strength is not improved.

As the aromatic solvent, benzene, toluene, ethylbenzene, (n-, i-) propylbenzene, (o-, m-, p-) xylene, (o-, m-, p)
-) Diethylbenzene and the like and mixtures thereof.

It is known that aromatic solvents also have an effect as a chain transfer agent, and the molecular weight can be adjusted by using these aromatic solvents and further using a molecular weight modifier together. Therefore, in the present invention, the concentration of the aromatic solvent is also taken into consideration as a relationship between the concentration of the initiator and the concentration of the molecular weight regulator.

The present inventors have maintained a high grafting amount of styrene on a rubbery polymer by using an organic peroxide, an aromatic solvent and a molecular weight regulator in the quantitative ratio shown in the formula [1]. It has been found that it is possible to reduce the particle size of the rubber-like polymer while keeping the particle size distribution relatively narrow and to obtain a rubber-modified styrene resin composition having an excellent balance between impact strength and fluidity. .

That is, in the present invention, the concentration of organic peroxide [I] (wt. Ppm) and the concentration of aromatic solvent [E]
(Wt.%) And the concentration of the molecular weight modifier [S] (wt.pp)
m) is expressed by the formula [1], 9 ≦ 15 [I] ^1/2 / [E] + [S] ^1/3 ≦ 21... [1] Preferably, the formula [2] 9 ≦ 15 [I] ^1/2 / [E] + [S] ^1/3 ≦ 15 It is important to use a polymerization raw material liquid that satisfies the following condition.

A step of forming a dispersed phase of a rubbery polymer at a styrene reaction rate of 20 to 35% in the first stirring tank using the polymerization raw material liquid is provided. After increasing the reaction rate to 50 to 95%, the remaining monomer and the solvent are separated to have a volume average particle diameter of 1 to 4 μm, preferably 1.5 to 4 μm, and 10% of the cumulative distribution of the particle diameter on a volume basis. Of the rubbery polymer dispersed particles having a value of the ratio of the value to the 90% value in the range of 3 to 20, preferably 3 to 15, has high fluidity at the time of molding and high impact strength. It is possible to produce a rubber-modified styrene-based resin composition having an excellent balance.

In particular, when a polymerization raw material solution that satisfies the condition of the formula [2] is used, in addition to the above-mentioned high fluidity and high impact resistance, the vibration damping property of the molded article (vibration is applied to the molded article). In addition to the improvement in the property of reducing the vibration when the molded article is formed, it also has the property of reducing the impact sound (the sound when the molded article is subjected to an impact is small). By utilizing this property, for example, a sheet obtained by laminating an iron plate and a sheet molded with the resin composition of the present invention can be used as a vibration absorbing plate or a soundproof plate for reducing sound upon impact.

It should be noted that the conventional HIP
In the case of S, when the nail was hit on the molded product, the molded product was cracked. On the other hand, the molded product of the rubber-modified styrene resin composition of the present invention could be nailed.

In the present invention, a diene rubber-like polymer is preferable as the rubber-like polymer, and the above-mentioned styrene-based monomer or a mixture of the above-mentioned monomers to which a predetermined amount of the rubber-like polymer has been added is polymerized. The rubbery polymer is formed into dispersed particles in the styrene-based polymer.

Here, the rubbery polymer has a 5% by weight styrene solution viscosity measured at 25 ° C. of 20 to 100 centipoise, preferably 30 to 90 centipoise.
The diene-based rubbery polymer is a homopolymer of a diene compound or a copolymer of a diene compound and another monomer in a rubbery state.
A butadiene polymer having a bonding ratio of 90 mol% or more, or a styrene / butadiene copolymer is preferred.

The proportion of the diene rubbery polymer used is preferably 3 to 20 parts by weight, more preferably 5 to 20 parts by weight, based on 100 parts by weight of the polymerization raw material liquid.

In the present invention, the rubber-like polymer particles formed as described above have a volume average particle diameter of 1 to 4 μm.
Need to be Here, the volume average particle diameter is measured as follows. That is, the resin is used as an ultra-thin section sample by an ultra-thin section method, and an electron micrograph thereof is taken. The short diameter and the long diameter of 500 to 700 rubbery polymer particles in the photograph are measured, and the average is defined as the particle diameter, and the volume average particle diameter is calculated by the following equation.

Volume average particle diameter ΔnD ⁴ / ΔnD ³ (where n is the number of rubber-like polymer particles having a particle diameter of D μm)

When the volume average particle diameter is less than 1 μm, the impact strength of the obtained rubber-modified styrenic resin is low, and when it exceeds 4 μm, the appearance of the molded product, particularly the surface gloss, is reduced.

The volume average particle diameter is adjusted by the stirring intensity of the stirrer, the reaction temperature and the amount of the organic peroxide in the reaction vessel for converting the rubbery polymer into particles. It becomes smaller, the particle size becomes larger if the reaction temperature is increased, and the particle size becomes smaller if the organic peroxide is increased.Therefore, it can be controlled by adjusting these values within the scope of the present invention. it can.

In the present invention, the number of the rubber-based polymer particles is counted from the larger volume-based particle diameter of the rubber-like polymer particles, and the particle diameters D1 and 90% at which the cumulative particle diameter distribution becomes 10% are obtained. D1 / D2 of the ratio of particle diameter D2
By adjusting the distribution coefficient (hereinafter referred to as the distribution coefficient) in the range of 3 to 20, a rubber-modified styrene-based resin composition having an excellent balance between physical properties of fluidity and impact strength can be produced.

When this value is preferably in the range of 3 to 15, the effect of improving the impact strength and the appearance, particularly the gloss, of the molded product are improved. The distribution coefficient can be adjusted by the molecular weight distribution of the rubbery polymer, the mixing ratio of the rubbery polymer, the stirring intensity and the residence time during polymerization, the amount of the organic peroxide, and the like. Also, if the stirring intensity is large, the distribution coefficient is small,
If the residence time is made longer, the distribution coefficient becomes smaller. Therefore, by adjusting these, the distribution coefficient can be controlled.

Outside this range, particles having a very large volume average particle diameter or particles having an abnormal shape are generated, so that the impact strength is reduced and the appearance of the molded product is unfavorably deteriorated.

In the present invention, the conversion of the styrene monomer is controlled by a known method, for example, the polymerization temperature, the type and concentration of the polymerization initiator used, the residence time and the like.

The polymerization temperature in the method of the present invention is usually 5
It is 0-200 degreeC, Preferably it is 80-150 degreeC.

The higher the polymerization temperature, the higher the conversion,
If the concentration of organic peroxide is increased, the conversion rate is increased.If the polymerization time is increased, the conversion rate is increased.If the residence time is increased, the conversion rate is increased. Can be controlled.

In order to produce the resin of the present invention having an excellent balance of physical properties, a continuous bulk polymerization or a continuous solution polymerization is carried out to form a rubbery polymer dispersed phase by a polymerization step. It is necessary to separately control at least two steps including a step of controlling the particle diameter and the particle diameter distribution of the particles and a step of increasing the polymerization rate. That is, the raw material monomer is continuously supplied to the polymerization reaction step, and in the first step, the reaction rate of styrene is 2 in the complete mixing type reaction tank.
The polymerization reaction is carried out to 0 to 35% to form a dispersed phase of the rubbery polymer, the particle size and the particle size distribution of the rubbery polymer particles are controlled, and the reaction is continuously performed in a continuously connected reaction tank. An extremely high fluidity and impact strength can be imparted by increasing the reaction rate by reacting it to 50 to 95% and continuously taking out the resulting polymer from the polymerization reaction step.

In the first step, as the polymerization proceeds from the polymerization raw material solution in which the rubbery polymer is dissolved and the amount of the styrene-based polymer increases, the rubber-like polymer The polymer components undergo phase separation and form particles by shearing with stirring. At that time, the particle size and the particle size distribution are adjusted. Therefore, the reaction tank used in the first step needs to be a completely mixed type reaction tank. When the complete mixing type reaction tank is not used, or when the conversion of styrene is less than 20% or more than 35%, it is difficult to adjust the particle size of the rubbery polymer, and the rubbery polymer particles having a large particle size are difficult to adjust. Uneven rubber-like polymer particles are formed and impact strength is lowered and fluidity is lowered, which is not preferable.

In the present invention, the complete mixing type reaction vessel does not necessarily need to be a reaction vessel capable of performing ideal perfect mixing, and a shearing action is caused by stirring, whereby a rubbery polymer particle can be formed. Any reaction vessel having a machine can be used. For example, "New polymer manufacturing process"
(Industry Research Committee, written by Yasuharu Saeki, Koji Saeki, Shinzo Omi) 18
These are described in FIG. 7.3, FIG. 7.4 on page 2 to page 187, and FIG. 7.3, FIG. 7.4, FIG. 7.5 and FIG. 7.6 on page 187.

Following the first step of forming the rubber-like polymer particles, a post-polymerization step is carried out to further increase the polymerization conversion while maintaining the shape of the rubber-like polymer particles. In the process, the type of the reaction tank is not particularly limited,
Not only a stirring tank such as a complete mixing stirring tank or a tower-type mixing stirring tank, but also a tubular reaction tank can be used. At the end of the post-polymerization step, the conversion of the monomer into the polymer is 50 to 9
0% by weight, preferably 50 to 85% by weight, more preferably 50 to 80% by weight.

The molded article using the rubber-modified styrene resin produced according to the present invention has a significantly higher fluidity when molding a molded article, while exhibiting a higher impact strength value than the conventional method. In general, it is not clear why the impact strength is maintained high in the present invention, although the impact strength is reduced when the fluidity of the rubber-modified styrene resin is increased, but a catalyst (organic peroxide) is required for high grafting. Even if a large amount of is used is within the range of the relationship of the formula [1] of the present invention, even if the molecular weight of the styrenic resin is reduced, the particle size becomes small and the particle size distribution can be controlled to be small, so that the rubbery polymer It is considered that the particles are relatively uniform and the fluidity when molding a molded article is greatly improved.

The rubber-modified styrenic resin obtained in the present invention is obtained by graft-polymerizing a styrene-based polymer contained in a diene-based rubbery polymer as a disperse phase onto the diene-based rubbery polymer. ing. This has been confirmed by the fact that the polystyrene and the rubbery polymer cannot be separated even when the polymerization reaction solution after the polymerization is analyzed by GPC-IR.

The rubber-modified styrenic resin composition of the present invention may contain, if necessary, an antioxidant such as a phenolic antioxidant, a phosphorus-based antioxidant, and a sulfur-based antioxidant, and a fluidity improver such as mineral oil. , Stearic acid, zinc stearate,
A release agent such as an organic polysiloxane may be added during the polymerization raw material liquid or during or after the polymerization.

[0056]

EXAMPLES The present invention will be described in more detail with reference to the following Examples, which do not limit the scope of the present invention. The evaluation methods of the physical properties in the examples and comparative examples were performed by the following methods. (1) MFI: JIS K-7210 (Temperature: 200
° C, load 49N) (2) Izod impact strength: JIS K-7110
(6.4 mm / notched). (3) Nailability: When a nail having a thickness of 1 mm is hammered into the center of a disk-shaped test piece having a thickness of 3.2 mm and a diameter of 5 cm with a hammer, a piece that does not crack or chip is good. What occurred was regarded as defective.

Example 1 A rubber-modified styrene resin was produced by using a continuous mass polymerization apparatus in which a preheater was connected to the outlets of four series-mixed reaction tanks with a stirrer, and a vacuum tank was connected. As the rubbery polymer (I), the first complete mixing type reaction vessel equipped with a stirrer
5 ° C., 5 wt% styrene solution viscosity 32 centipoise, 9 parts by weight of a butadiene polymer having a 98% cis 1,4 bond ratio, 22 parts by weight of ethylbenzene, 69 parts by weight of styrene,
1,1-bis (t-
Butylperoxy) 3,3,5-trimethylcyclohexane 200 wt. The polymerization raw material liquid of 1 ppm was continuously supplied, and the reaction was carried out at a stirring speed of a stirrer of 95 rpm.

In the first group, the reaction temperature was 142 ° C., and the residence time was 1.5 hours. The second one is a reaction temperature of 145 ° C,
The residence time was set to 2 hours, and the third reaction temperature was set to 145.
° C and the residence time was 2.5 hours. The preheater temperature is 2
The temperature is maintained at 10 to 240 ° C., and the degree of vacuum in the vacuum chamber is 40 Torr.
r. Table 1 shows the results.

Example 2 In Example 1, 30 parts by weight of ethylbenzene, 61 parts by weight of styrene, and 1,1-bis (t-butylperoxy) 3,3,5-trimethylcyclohexane 200
wt. ppm and the first stirring speed was 400 rpm
The procedure was performed under the same conditions as in Example 1 except that Table 1 shows the results.

Comparative Example 1 Polymerization was carried out under the same conditions as in Example 1 except that the organic peroxide was not used and the butadiene polymer was 2.5 parts by weight. The resulting product has an Izod impact strength of 4.5 kJ /
was as low as m ^2.

Example 3 In Example 1, 5 parts by weight of a butadiene polymer was used, 22 parts by weight of ethylbenzene, 73 parts by weight of styrene, and 200 parts by weight of t-butyl dodecyl mercaptan as a molecular weight modifier based on styrene. A rubber-modified styrenic resin was produced under the same conditions as in Example 1 except that the ppm was changed to ppm. Table 1 shows the results.

Example 4 The procedure of Example 1 was repeated, except that the butadiene polymer was changed to 15 parts by weight, ethylbenzene 22 parts by weight, and styrene 63 parts by weight. Table 1 shows the results.

Example 5 In Example 1, 9 parts by weight of a butadiene polymer, 22 parts by weight of ethylbenzene, 69 parts by weight of styrene, and 1,1-bis (t-butylperoxy) 3,3,3
5-trimethylcyclohexane 50 wt. ppm, t-
Butyl dodecyl mercaptan was added in an amount of 200 wt. The procedure was carried out under the same conditions as in Example 1 except that ppm was used. Table 1 shows the results.

Example 6 In Example 5, 9 parts by weight of a butadiene polymer, 22 parts by weight of ethylbenzene, 69 parts by weight of styrene, and 1,1-bis (t-butylperoxy) 3,3,3
5-trimethylcyclohexane 100 wt. ppm, t
The reaction was carried out under the same conditions as in Example 5 except that -butyl dodecyl mercaptan was not used. Table 1 shows the results.

Example 7 A rubber-modified styrene resin composition was produced using a continuous bulk polymerization apparatus in which three premixers were connected to the outlets of a complete mixing type reaction vessel equipped with a stirrer and a vacuum vessel. A block type, a styrene content of 20 wt%, a 5 wt% styrene solution at 25 ° C., a 5 wt% styrene solution at 25 ° C., a styrene / butadiene copolymer having a viscosity of 32 centipoise as a rubbery polymer (I) in a first complete mixing type reaction vessel with a stirrer 12 parts by weight, ethylbenzene 1
8 parts by weight, styrene 70 parts by weight, 1,1-bis (t-butylperoxy) 3,3,5-trimethylcyclohexane 200 wt. ppm of the polymerization raw material liquid was continuously supplied. The stirring speed of the first stirrer was 300 rpm, the reaction temperature was 142 ° C., and the residence time was 1.5 hours. The second unit has a reaction temperature of 145 ° C. and a residence time of 2 hours, and the third unit has a reaction temperature of 145 ° C.
The residence time was 2.5 hours. The temperature of the preheater is 210-
The temperature was maintained at 240 ° C., and the degree of vacuum in the vacuum chamber was set to 40 Torr to produce a rubber-modified styrene resin composition. Table 1 shows the results.

Example 8 In the same manner as in Example 1, 74 parts by weight of styrene, 6 parts by weight of a rubbery polymer, 20 parts by weight of ethylbenzene, 200 wt. ppm, molecular weight regulator 250 wt. p
Table 1 shows the results of polymerization as pm.

Comparative Example 2 In the method of Example 1, the temperature of the first reaction tank was lowered,
Polymerization was carried out in the same manner except that the conversion of styrene was 10%.
Was. In the first reaction tank, the particle size cannot be sufficiently controlled,
The diameter has increased. Rubber-like polymerization of the obtained resin composition
The body particle diameter is 4.2 μm, the distribution coefficient is 25, and the MFI is 2.
8. Izod impact strength is 11KJ / m ^ThreeAnd MF
I is too low to obtain the desired resin composition of the present invention
Was.

[0068]

[Table 1]

[0069]

The rubber-modified styrenic resin composition of the present invention has an excellent balance between impact strength, fluidity of the resin, and appearance, particularly gloss, and is used for parts materials of household electric appliances and electronic equipment. The industrial utility value is great.

 ──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Masato Takaku 1-6-6 Takasago, Takaishi-shi, Osaka Mitsui Chemicals, Inc.

Claims (10)

[Claims] 1. A continuous polymerization apparatus comprising two or more reaction tanks including at least one complete mixing type reaction tank, wherein the continuous phase is a styrene resin by bulk polymerization or solution polymerization.
A method for producing a rubber-modified styrenic resin composition comprising a diene-based rubbery polymer in which a disperse phase includes a styrene-based resin, wherein a raw material to be charged into a first complete mixing reactor of a polymerization system (Hereinafter referred to as “polymerization raw material liquid”), when (1) styrene monomer, aromatic solvent and diene rubber polymer are 100 parts by weight in total, (a) styrene monomer 60 to 85 parts by weight (b) 5 to 35 parts by weight of an aromatic solvent, and (c) viscosity of a 5% by weight styrene solution at 25 ° C. of 30 to 9
0 to 2 parts by weight of a diene-based rubbery polymer having 0 centipoise, and (2) 20 to 300 wt. ppm, (b) molecular weight regulator 0-350 wt. ppm, and (3) the concentration of the organic peroxide in the polymerization raw material liquid is [I] (wt. ppm) and the concentration of the aromatic solvent is [E].
(Wt.%) And the concentration of the molecular weight modifier are [S] (wt.
ppm), [I], [E], and [S] are expressed by the following formula [1], 9 ≦ 15 [I] ^1/2 / [E] + [S] ^1/3 ≦ 21... .. Using a polymerization raw material liquid satisfying the relational expression represented by [1], a styrene-based monomer was added in a first complete mixing type reaction tank in an amount of 20 to 35.
% To form a dispersed phase composed of the rubbery polymer, and subsequently increase the conversion of the styrene monomer to 50 to 95% in the subsequent reaction tank, and further separate the solvent from the remaining monomer. The rubber-like polymer particles, which are the dispersed phase, have a volume average diameter of 1 to 4 μm, and the ratio (D1) between the 10% value (D1) and the 90% value (D2) of the cumulative particle size distribution on a volume basis. A method for producing a rubber-modified styrenic resin composition wherein / D2) is in the range of 3 to 20. 2. The rubber-modified styrenic resin according to claim 1, wherein the styrene-based polymer contained in the diene-based rubbery polymer as the dispersed phase is graft-polymerized to the diene-based rubbery polymer. A method for producing the composition. 3. [I], [E] and [S] are represented by the following formula [2], 9 ≦ 15 [I] ^1/2 / [E] + [S] ^1/3 ≦ 15... The method for producing a rubber-modified styrenic resin composition according to claim 1, wherein a polymerization raw material liquid satisfying the relational expression represented by [2] is used. 4. The method for producing a rubber-modified styrenic resin composition according to claim 1, wherein the styrenic monomer is styrene. 5. The method for producing a rubber-modified styrenic resin composition according to claim 1, wherein the aromatic solvent is at least one selected from benzene, toluene and ethylbenzene. 6. The method for producing a rubber-modified styrenic resin composition according to claim 1, wherein the diene-based rubbery polymer is at least one selected from a butadiene polymer and a styrene / butadiene copolymer. 7. The method for producing a rubber-modified styrenic resin composition according to claim 1, wherein the organic peroxide is 1,1-bis (t-butylperoxy) 3,3,5-trimethylcyclohexane. 8. The method for producing a rubber-modified styrenic resin composition according to claim 1, wherein the molecular weight modifier is a mercaptan compound. 9. The rubbery polymer particles as a dispersed phase have a 10% value (D1) and a 90% value in a cumulative particle size distribution on a volume basis.
The method for producing a rubber-modified styrenic resin composition according to claim 1, wherein the ratio (D1 / D2) to the value (D2) is in the range of 3 to 15. 10. The diene rubbery polymer contains 90 mol% of cis-1,4 bonds in the butadiene unit of the chain.
The method for producing a rubber-modified styrenic resin composition according to claim 1, which is a butadiene polymer as described above.