JPH01287135A - Copolyester having improved anisotropy - Google Patents

Abstract

PURPOSE:To obtain the subject polyester capable of giving injection molding without crack in the direction of orientation, having excellent mechanical strength, heat resistance, moldability, fire resistance, chemical resistance and mold shrinkage characteristic, etc., by copolymerizing plural components containing isophthalic acid. CONSTITUTION:(A) Polyethylene terephthalate as a composing unit of formula I is mixed with (B) 4,4'-biphenol (derivative) as a composing unit of formula II, (C) terephthalic acid (derivative) as a composing unit of formula III, (D) isophthalic acid (derivative) as a composing unit of formula IV and (E) parahydroxybenzoic acid (derivative) in the ratios of 2-15mol% component A, 5-30mol% component B, 1-20mol% component D and 30-85mol% component E to total mol number of components A+B+C+D+E and mol ratio of components (C+D)/component B is 0.8-1.1, then subjected to polycondensation to afford the aimed polyester.

Description

DETAILED DESCRIPTION OF THE INVENTION <Industrial Application Field> The present invention relates to a copolyester having improved mechanical strength, heat resistance, moldability, and anisotropy.

<Prior art> Liquid crystalline polyester has a low melt viscosity, so it can be easily molded, and the molded product has a high crystallinity, so it has a self-reinforcing effect, has excellent mechanical strength, and has a low coefficient of linear expansion and molding shrinkage. It has properties such as excellent flame retardancy, chemical resistance, and solvent resistance.

Among them, polyethylene terephthalate component, 4.4'-
The copolymerized polyester disclosed in Japanese Patent Application No. 62-332516, which is composed of a biphenol component, a terephthalic acid component, and a parahydroxybenzoic acid component, has the above-mentioned characteristics of the liquid crystal polyester, and also has excellent moldability and high heat resistance. Resin Tea Ru.

<Problems to be Solved by the Invention> However, the copolyester disclosed in Japanese Patent Application No. 62-332516 has a drawback of large anisotropy in mechanical strength.

In other words, the direction of orientation of the resin (M
The strength and elastic modulus of the D force direction and the direction perpendicular to this (TD force direction) are very different. Breakage of a molded product due to external force generally occurs from the weakest point, and the In this case, MD force direction cranking of the injection molded product occurs.

Although the copolyester consisting of molecules with good symmetry as disclosed in Japanese Patent Application No. 62-332516 has many excellent properties necessary for injection molded products, it has a large anisotropy and cannot be easily oriented in the orientation direction. It has the fatal disadvantage of being easily cracked, and its uses are extremely limited.

In addition, as a method of alleviating anisotropy, Japanese Patent Application No. 62-3
Is there a method of filling glass fiber etc. as disclosed in No. 32517, but this also has disadvantages due to adding inorganic substances,
For example, screw wear during kneading, decrease in strength, decrease in fluidity, decrease in electrical properties, poor appearance, etc. are undesirable.

<Means for Solving the Problems> The present inventors have conducted intensive studies on polymer compositions that can further enhance the strength and modulus of elasticity of the resin, and have found that a polyester component, a 4,4'-biphenol component, This was achieved by adding isophthalic acid as a fifth component to the terephthalic acid component and the oxybenzoic acid component. Furthermore, surprisingly, it was found that the addition of isophthalic acid alleviated the anisotropy and significantly improved the practical strength of the molded product, leading to the present invention.

Therefore, the unit contains the following structural units (I) to (V) and is based on the total number of moles of units (I), (I+), (III), (IV), and (V). (■)2
~15 mol%, unit (I+) 5-30 mol%, unit (■
) 1 to 20 mol%, IL position (v) 3o to 85%,
And (unit (m) thousand unit (IV))/! 1st place (TI
) = 0.8 to 1.1 (molar ratio).

(Here, some of the hydrogen atoms on the aromatic rings of units (r) to (V) may be substituted with 01 to C6 lower alkyl groups, alkoxy groups, and halogen groups.) The present invention will be explained below. Explain in detail.

The copolymerized polyester of the present invention has the following structural units (1) to
Contains (V).

The unit (I) is represented by , and is produced using polyethylene terephthalate as a repeating unit or an ethylene glycol component and a terephthalic acid component as raw materials. It can also be provided in copolymerized polyesters.

Unit (I) should be present in an amount of 2 to 15 mol% based on the total number of moles of units (I) to (V) combined, and if it is less than 2 mol%, the melting temperature of the resulting copolymerized polyester will increase. This makes manufacturing and molding difficult, and is undesirable because coloration and thermal deterioration of the resin occur during melt polymerization and melt molding. If it exceeds 15 mol %, the melting temperature decreases, which has the advantage of making manufacturing and molding easier, but it also has the disadvantage of decreasing heat resistance. The preferred amount of unit (I) is 3 to 10 mol%.

FIG. 1 shows the reason why the amount of unit (I) is within this range.

That is, as will be detailed later in Example 2.3, the copolymerized polyester has an isophthalic acid content of 2 mol% (
Composition A) and 5 mol % (composition) of composition A; composition.

The injection molding temperature and heat distortion temperature of the resins were synthesized and the amounts of x and y of unit (I) were changed, and the horizontal axis is the content (mol%), as shown in Figure 1. .

If the range is 2 mol % to 15 mol %, the injection molding temperature and heat distortion temperature will be lowered, and manufacturing and molding will be easier.

The unit (II) is represented by -(-si(Σ(Σ0+), which can be provided in the copolyester using 4,4'-biphenol and its derivatives as raw materials.

The unit (11) should be present at 5 to 30 mol%, based on the total number of moles of units (1) to (V) combined, and 5 mol%
When the amount is less than 30 mol %, the mechanical strength of the resulting copolyester decreases. The preferred amount of unit (II) present is 7 to 20 mol%.

The unit (U+) is represented by 2, and can be provided in the final copolymerized polyester by using terephthalic acid and its derivatives as raw materials.

Unit (II+) is unit (II+) and unit (IV) (
7) The sum should be within the range of (units (Ill) thousand units (■))/units (II) - 8 to 1.1 (molar ratio), and outside this range the copolymerization that occurs Decrease in heat resistance of polyester, discoloration of resin,
This is not preferable because it causes a decrease in mechanical strength.

FIG. 2 shows the reason why the abundance of the sum of the unit (Ill) and the unit (IV) is kept within this range with respect to the unit (rr).

That is, as will be described later in detail in Example 6, the Izot impact strength and thermal deformation of resins in which "0(Σ'jj"70) was synthesized as a copolymerized polyester and Z, which is the amount of units (Ill) present, were The temperature is set as M and II, and the horizontal axis is shown in Figure 2 as (units (Ill) thousand units (1)/units (II) = ζΣ(Σ0+ (Z+3)/11.5 (molar ratio)). That is, if the amount of each component is within this range, the Izot impact strength will improve and the heat distortion temperature will also increase.

The unit (IV) is represented by 1 and can be provided in the final copolymerized polyester by starting from isophthalic acid and its conductor.

The unit (IV) should be present in an amount of 1 to 20 mol% based on the total number of moles of the units (1) to (V).
If it is less than 1 mol%, the bending strength, bending modulus and relaxation of anisotropy will not be sufficiently improved, and if it exceeds 20 mol%, although there is an advantage of lowering the melting temperature, thermal deformation will be greater than that. This is not preferable because it causes a drop in temperature.

The amount of unit (IV) present is 3 to 10 mol%, more preferably 3 to 5 mol%.

The reason for keeping the amount of unit (IV) within this range is shown in FIGS. 3 to 6.

That is, as will be detailed later in Example 4.5, as a copolymerized polyester, the following composition was synthesized, and the melting temperature of the resin was changed by changing the amounts of d and m of the unit (IV). and the heat distortion temperature, and the bending strength, practical strength and molding shrinkage of the resin of composition C,
The abscissa axis is shown in FIGS. 3 to 6 as the abundance of unit (IV). That is, when the unit (IV) is within the above range, the melting temperature is lowered, the bending strength and the bending elastic modulus are improved, and the molding shrinkage rate is reduced.

The unit (V) is represented by the following formula, and can be provided in the copolyester by using parahydroxybenzoic acid and its derivatives as raw materials.

The unit (V) is present in an amount of 30 to 85 mol% based on the total number of moles of units (I) to (V).
) is less than 30 mol% or exceeds 85 mol%, the mechanical strength is significantly reduced. The amount of unit (V) present is preferably 40' to 80 mol%, more preferably 55 to 73 mol%.

FIG. 7 shows the reason why the amount of unit (V) is kept within this range.

That is, as will be described later in detail in Example 7, as a copolymerized polyester, +0'-C> rule.

○ was synthesized, and the bending strength and Izot impact strength of the resin were measured by changing f, which is the abundance of unit (V), and the horizontal axis was expressed as unit (
The abundance of V) is shown in FIG.

When the amount of unit (V) is within this range, both the bending strength and the isot impact strength are improved.

Units (1) to (V) are part of the hydrogen atom on the aromatic ring, or are C
It may be substituted with a 5-C6 lower alkyl group, an alkoxy group, or a halogen group.

Specifically, the unit (I) is a 3,3',5.5'-tetramethyl-4,4'-dihydroxybiphenyl substituted with a hydrogen atom or a methyl group on the aromatic ring;
ll) is dichloroterephthalic acid or dibromo terephthalic acid substituted with a halogen group, unit (TV) is 4-methyl 4-sophthalic acid or t-butyl isophthalic acid substituted with a methyl group or t-butyl group, and unit ( Examples of V) include 4-hydroxy-3-methoxybenzoic acid and 4-hydroxy-3-chlorobenzoic acid substituted with a methoxy group or a halogen group.

The polymerization method is not particularly limited, and any polymerization method may be used as long as the units (I) to (V) are present in the composition ratio of the present invention in the copolymerized polyester.

Polyethylene terephthalate corresponding to unit (I), biphenol corresponding to unit (II), unit (III)
Direct polymerization method in which a catalyst is added to terephthalic acid corresponding to unit (IV), isophthalic acid corresponding to unit (IV), and parahydroxybenzoic acid corresponding to unit (V), and polymerization is performed while heating and removing the generated water: Direct polymerization A method in which the carboxyl groups of legally used raw materials are roughened and esterified with phenol derivatives, and the raw materials are heated and polymerized while removing the phenol derivatives produced.

A method in which the aromatic hydroxyl group of the raw material used in the direct polymerization method is acylated with an organic acid, and the raw material is heated and polymerized while removing the generated organic acid; The carboxyl group of the raw material used in the direct polymerization method is converted into an acid halide. Any method of polymerizing while removing hydrogen halide produced using a raw material can be used.

In addition, melt polymerization method, heated solution polymerization method, low temperature solution polymerization method,
Polymerization is possible by any interfacial polymerization method.

Among these methods, the most desirable is the melt polymerization method in which polymerization is performed while removing the organic acid.

As a representative example, a melt polymerization method in which polymerization is performed by acidolysis reaction will be explained in detail.

The reaction is initiated by placing necessary raw materials, namely polyester, aromatic diacyloxy compound, aromatic dicarboxylic acid compound, and aromatic acyloxycarboxylic acid compound in a polymerization container and heating them.

There is no particular limit to the polymerization temperature, but -180 to 40 for boat fishing.
It is carried out between 0°C. If the temperature is lower than 180°C, the reaction will be slow, and if it exceeds 400°C, coloration or decomposition of the polymer will occur, which is not preferable.

The preferred polymerization temperature is in the range of 200-360°C.

The pressure during the reaction is not particularly limited, but it is preferable to carry out the reaction at around atmospheric pressure at the initial stage and gradually reduce the pressure as the polymerization progresses.

In order to prevent the decomposition of the polymer due to local overheating and to facilitate the removal of the organic acids produced, it is preferable to carry out the reaction with stirring, and in order to prevent the oxidative decomposition of the polymer due to oxygen, the atmosphere in the reaction system should be filled with nitrogen or An inert gas atmosphere such as argon is desirable.

The polymerization reaction can be carried out without using a catalyst, but a catalyst may be used to accelerate the polymerization reaction. The catalyst is
It may be mixed into the polyester of unit (I), which is a starting material, or may be newly added at the polymerization stage.

Catalysts include germanium compounds such as kermanium oxide, tin compounds such as stannous oxalate, stannous acetate, dialkyltin oxides, diaryltin oxides, titanium dioxide, titanium alkoxides, and alkoxytitanium silicates. Titanium compounds such as salts, antimony compounds such as antimony trioxide, metal salts of organic acids such as sodium acetate, potassium acetate, calcium acetate, zinc acetate, ferrous acetate, Lewis acids such as BF and AuCu3 , azines, amides, and inorganic acids such as hydrochloric acid and sulfuric acid.

Fillers, additives, etc. may be added to the copolymerized polyester of the present invention during polymerization or to the obtained copolymerized polyester. These include, for example, inorganic fillers such as talc, calcium carbonate, mica, wollastonite, ferrite, rare earth magnet powder; glass fiber; carbon fiber.

Asbestos m-fiber; Antioxidant: Anti-coloring agent, stabilizer; Ultraviolet/ray absorber: Plasticizer; Lubricants such as molybdenum disulfide, silicone oil, fluororesin, graphite; Tetrabromo bisphenol A, antimony trioxide, etc. Examples include flame retardants.

Applications of the copolymerized polyester of the present invention include precision injection molded products for electrical and mechanical parts that take advantage of its mechanical and dimensional properties; plastic magnets filled with ferrite and rare earth magnets, and high-strength products made by melt spinning. Elastic modulus fiber;
Examples include film.

In particular, it is preferable to utilize the copolymerized polyester of the present invention as an injection molding material by taking advantage of its low melting temperature, low melt viscosity, high heat resistance (heat distortion temperature), and low anisotropy.

Next, the characteristics of the present invention will be described while comparing the copolymerized polyester of the present invention with copolymerized polyesters described in known literature.

Copolyester containing no unit (I) was published in Japanese Patent Publication No. 47.
-47870, this polyester is
As shown in the representative example with composition E in the figure, the melting temperature is 350
It has the disadvantage of exceeding ℃.

That is, in the case of melt polymerization, there are many disadvantages in production when the reaction temperature exceeds 350°C.

First of all, heating above 350° C. is difficult with an organic heating medium, and heating with an electric heater or an inorganic molten salt such as nitrate must be used.

The former causes coloring and decomposition of the polymer due to local overheating, and the latter is difficult to handle. Second, coloring and decomposition of polyester occur rapidly at 350°C. In order to prevent this, a method is often used in which a prepolymer is synthesized at a relatively low temperature and the prepolymer is polymerized in the same phase under an inert gas or reduced pressure, but this method also has the disadvantage of complicating the equipment.

Therefore, it is important for the melting temperature of the copolyester to be 350° C. or lower in terms of manufacturing equipment and obtaining good molded products. Unit (I) is an essential component for lowering the melting temperature.

Since the copolyester of the present invention melts at 350° C. or lower, it can be produced using general melt polymerization manufacturing equipment used for polyethylene terephthalate, etc., and is an almost white resin with an excellent appearance.

Copolyester containing no unit (IV) is patented in 1986.
2-332516, but this polyester has the drawback that the strength in the MD force direction and the TD force direction of the injection molded product differs greatly as shown by the horizontal axis O in FIG. 4, and the strength in the TD force direction is low.

In other words, breakage of a molded product due to external force generally occurs from the weakest point, and when the anisotropy is large in this way, the orientation direction is likely to break, and its uses are extremely limited.
In order to improve the practical strength of molded products, it is essential to improve the strength in the TD force direction and the elastic modulus.

By adding isophthalic acid as a fifth component to the copolymerized polyester of the present invention, it is possible to further increase the strength and elasticity of the resin containing no isophthalic acid component, as shown by 1 to 20 mol% on the horizontal axis in FIG. In particular, the strength in the TD force direction was significantly improved, and the anisotropy could be alleviated. This was also confirmed by the decrease in molding shrinkage as shown in FIG. In addition, the strength in the TD force direction was high, and in addition, as shown in FIG. 5, the practical strength was significantly improved.

As shown in FIGS. 1 and 3, both the unit (■) and the unit (■) are effective as means for lowering the melting temperature. However, unit (IV) has a smaller decrease in melting temperature per content than unit (I), and also has a large decrease in heat resistance (heat distortion temperature). In addition, as shown in Figure 5, since the improvement in practical strength by adding the unit (IV) is satisfied by approximately 3 mol%, the unit (IV) is fixed at about 3 mol%, and the unit (1 ) is 6 mol % or more, synthesis can be performed at 350° C. or lower, and this can be said to be the most ideal polyester composition in terms of manufacturing, equipment, and obtaining good molded products.

<Example> The present invention will be specifically explained below using Examples.

First, the test method will be explained.

(1) Injection molding ■ Using a 5AV-60-52 injection molding machine manufactured by Yamaguchi Seiki Seisakusho, mold temperature 70°C, injection pressure 250 kg/cm
2. Set the cylinder temperature to a temperature at which the resin is sufficiently grooved in the mold with this injection pressure, and make 5 x 1/2 x 1
A 78 inch test piece was obtained.

The injection molding temperature refers to the cylinder temperature at this time.

In addition, a 120xl 20x2mm (fan gate) flat plate was molded at a mold temperature of 130°C and an injection pressure of 150 kg/c.
m2, and the cylinder temperature was 5° C. higher than when the 5 x 1/2 x 1/8 inch test piece was molded.

(2) Physical property evaluation Heat distortion temperature (18.6 kg/cm2) is ASTM D-6
48, Izotsu impact strength (with notch) is ASTM
D-256, molding shrinkage rate is ASTM D-955
Measurements were made using a 5 x 1/2 x 1/8 inch test piece.

The anisotropy test was conducted using a 120xl 20x2mm flat plate in the flow direction of the resin (MD force direction and in the direction perpendicular to the flow direction (TD
Cut out a 14mm width in the force direction, ASTM D-79
A bending test was conducted in accordance with 0.

(3) Melting temperature φQ, 5x1. The temperature was determined when the resin had a viscosity of 1000 voices using a nozzle of 0 mm and a heating rate of 6° C./min. That is, the melting temperature refers to the temperature at which the resin has 1000 voids.

(4) Practical strength Practical strength is ■Using a DuPont impact strength measuring device manufactured by Toyo Seiki Seisakusho, a striking center of R = 7.9 mm is applied to the center of a 120xl 20x2mm flat plate, a 200g weight is dropped, and the flat plate cracks. The height at which this occurred was determined, and the practical strength was expressed in terms of this fracture height (cm).

Next, the copolyester of the present invention will be described.

(Example 1) Stirring device with torque meter/tachometer, argon introduction pipe,
Polyethylene terephthalate (phenol/tetrachloroethane = 50150
(Weight ratio) Concentration of 0.5 g/du in solvent, logarithmic viscosity measured at 30°C is 0.72) 134 g (0.7 mol)
4.4'-diacetoxybiphenyl 297 g (1.1 mol), terephthalic acid 149 g (0.9 mol), isophthalic acid 33 g (o, 2 mol), paraacetoxybenzoic acid 1
278 g (7.1 mol) was charged.

After sufficiently purging with argon, the temperature was raised to an internal temperature of 260° C. over about 30 minutes. When the raw material melted during the temperature rise, stirring was started. After polymerization was carried out at 260°C for 1 hour, 280°C for 1 hour, and 300°C for 1 hour, the pressure was gradually reduced, and the polymerization was finally completed by reacting at 340°C and 0.5 mmHg for 20 minutes.

Physical properties were measured and the results are shown in Figures 1 and 3 to 6.

(Example 2) Synthesis and physical property measurements were carried out in the same manner as in Example 1, except that the raw materials and final synthesis temperature were as shown in the table below.

The results are shown in Table 1 and Figure 1.

Table 1 (Examples 3 to 7) Copolymerized polyesters having the compositions shown in Table 2 were synthesized in the same manner as in Example 1, except that the raw materials and final synthesis temperature were changed to 300 to 350°C, and the physical properties were measured. Ta. The results are shown in Figures 1 to 7.

(Comparative Example 1) As a comparative example, a polyester known in Japanese Patent Publication No. 47-47870 was used, and the raw materials and final synthesis temperature were 380 to 4.
It was synthesized in the same manner as in Example 1 except that the temperature was changed to 20°C, and the physical properties were measured. The composition of the synthesized copolyester is shown in Table 2, and the results are shown in FIG.

(Comparative Example 2) As a comparative example, a polyester known in Japanese Patent Application No. 62-332516 was used, and the raw materials and final synthesis temperature were 350°C.
It was synthesized and its physical properties were measured in the same manner as in Example 1, except for changing to . The composition of the synthesized copolyester is shown in Table 2.
The results are shown in Figures 3 to 6.

It should be noted that the copolymerized polyesters synthesized in Examples 1 to 7 and Comparative Examples 1 to 6 were all observed under a polarizing microscope (Nikon polarizing microscope POH type equipped with a heat stage).
When a light shearing force was applied to the material in the molten state, it showed optical anisotropy, which revealed that it was a thermodromic night-crystalline polyester.

JP 1-2'87135 (9) 〒　　　　　　　　- Monkey 〒- Shin JP-A-1-287135 (11).

Small 0 presentation″″″′.

<Effects of the Invention> The copolymerized polyester of the present invention has excellent heat resistance, mechanical strength, flame retardance, chemical resistance, solvent resistance, appearance, low linear expansion coefficient, low mold shrinkage rate, and low anisotropy. In addition, injection molding can be easily performed, and it can be easily manufactured using raw materials that are easy to handle.

[Brief explanation of the drawing]

Figure 1 shows the unit (I) component amount of the copolymerized polyester;
It is a graph showing the relationship between y and injection molding temperature and heat distortion temperature. FIG. 2 is a graph showing the relationship between (unit (m) + 4th position (IV))/JIL position (I+) of copolymerized polyester, heat distortion temperature and Izod impact strength. FIG. 3 is a graph showing the relationship between the amounts of unit (IV) components; d, m, and n of the copolymerized polyester, and the melting temperature and heat distortion temperature. Figure 4 shows the amount of unit (IV) component of the copolymerized polyester, d
It is a graph which shows the relationship between and bending strength. Figure 5 shows the amount of unit (IV) component of copolymerized polyester;
It is a graph showing the relationship between d and DuPont impact strength. Figure 6 shows the amount of unit (IV) component of copolymerized polyester,
It is a graph which shows the relationship between d and molding shrinkage rate. FIG. 7 is a graph showing the relationship between the amount of the unit (V) component and f of the copolymerized polyester, and the bending strength and the Izot impact strength.

Claims (1)

[Claims] (1) Contains the following structural units (I) to (V), and based on the total number of moles of units (I), (II), (III), (IV), and (V), Unit (I) 2-15 mol%, Unit (II) 5-30 mol%
, unit (IV) 1-20 mol%, unit (V) 30-85%
and {unit (III) + unit (IV)}/unit (II
) = 0.8 to 1.1 (molar ratio), a copolymerized polyester with improved anisotropy. ▲There are mathematical formulas, chemical formulas, tables, etc.▼(I) ▲There are mathematical formulas, chemical formulas, tables, etc.▼(II) ▲There are mathematical formulas, chemical formulas, tables, etc.▼(III) ▲There are mathematical formulas, chemical formulas, tables, etc.▼( IV) ▲Mathematical formulas, chemical formulas, tables, etc.▼(V) (Here, some of the hydrogen atoms on the aromatic rings of units (I) to (V) are C_1 to C_6 lower alkyl groups, alkoxy groups, and halogens. (May be substituted with a group.)