JPH0523570B2 - - Google Patents

Description

[Detailed description of the invention]

<Industrial Application Fields> The present invention provides a polymer with a high degree of polymerization that can be obtained only by melt polymerization, and has mechanical properties such as optical anisotropy, heat resistance, rigidity, and impact resistance that can be molded with a normal molding machine. This invention relates to an excellent copolyester injection molded product. <Conventional technology> In recent years, the demand for higher performance plastics has been increasing, and many polymers with various new performances have been developed. Among them, optically anisotropic liquid crystal polymers have excellent mechanical properties. (Japanese Unexamined Patent Publication No. 51-8395, Unexamined Japanese Patent Publication No. 49-1983)
Publication No. 72393). <Problems to be Solved by the Invention> As the above-mentioned liquid crystal polymer, for example, a liquid crystal polymer prepared by copolymerizing polyethylene terephthalate with p-hydroxybenzoic acid is known (Japanese Unexamined Patent Application Publication No. 1983-1970).
Publication No. 72393). However, injection molded products made of this polymer have drawbacks such as insufficient heat resistance and poor mechanical properties, and it has been found that injection molded products satisfying both properties cannot be obtained from this polymer. Moreover, to improve heat resistance, p-
Although the amount of hydroxybenzoic acid is required to be 80 mol% or more, it was also found that solidification occurs during polymerization and solid phase polymerization is necessary. On the other hand, as a means to improve the fluidity of such a polymer, improve its melt moldability, and further improve its mechanical properties, for example, as described in JP-A-51-8395, polyethylene A method has been proposed in which terephthalate is copolymerized with p-acylhydroxybenzoic acid, dicarboxylic acid, and aromatic diol, but although the mechanical properties of injection molded products obtained by this method are improved, the heat resistance is insufficient. I found out something. On the other hand, the special public official
As described in Publication No. 47870, an injection molded product made of a wholly aromatic polyester made by copolymerizing p-hydroxybenzoic acid with 4,4'-dihydroxybiphenyl and terephthalic acid has good heat resistance, but has a low softening temperature. It was found that melt polymerization was difficult because the temperature was 400°C or higher, and its mechanical properties were not fully satisfactory. Therefore, the object of the present invention is to obtain a copolyester injection molded product that can be molded using a common injection molding machine and has excellent mechanical properties and heat resistance. <Means for Solving the Problems> As a result of intensive studies to achieve the above object, the present inventors have arrived at the present invention. That is, the present invention provides the following structural units () to
(), the structural unit [() + ()] is 77 to 95 mol% of [() + () + ()], and the structural unit () is 23 to 23 mol% of [() + () + ()] 5 mol%, and the molar ratio of structural units ()/() is 75/25
Injection molded optically anisotropic liquid crystal polyester with ~95/5 logarithmic viscosity (0.1 g/dl concentration, measured in pentafluorophenol) of 0.5 to 5 dl/g
The heat distortion temperature (load 18.56Kg/cm ² ) is 150℃
The present invention provides a copolymerized polyester injection molded product as described above. (-O-R ₁ -O) - ... () (-O-CH ₂ CH ₂ -O) - ... () (-OC-R ₂ -CO) - ... () (However, R in the formula ₁ is

【formula】

【formula】

【formula】

【formula】

【formula】

R ₂ is one or more groups selected from [Formula]

【formula】

【formula】

【formula】

It represents one or more groups selected from [Formula], and X represents a hydrogen atom or a chlorine atom. Further, the structural unit [()+()] and the structural unit () are substantially equimolar. ) The above structural unit () is a structural unit generated from p-hydroxybenzoic acid, and the structural unit () is 4,4'-dihydroxybiphenyl, hydroquinone, 2,6-dihydroxynaphthalene, t-butylhydroquinone, 3, This figure shows a structural unit formed from an aromatic diol selected from 3',5,5'-tetramethyl-4,4'-dihydroxybiphenyl and phenylhydroquinone. In addition, the above structural unit () is a structural unit generated from ethylene glycol, and the structural unit () is a structural unit generated from terephthalic acid, 4,4'-diphenyldicarboxylic acid,
2,6-naphthalene dicarboxylic acid, 1,2-bis(phenoxy)ethane-4,4'-dicarboxylic acid,
1,2-bis(2-chlorophenoxy)ethane-
It is a structural unit produced from an aromatic dicarboxylic acid selected from 4,4'-dicarboxylic acids. Among these, as R ₁

[Formula], as R ₂

The formula is most preferred. On the other hand, among the above structural units () to (), the structural unit [() + ()] is [() + () + ()]
77
~95 mol%. Also, the structural unit () is [() + () + ()]
It is 23 to 5 mol%. If the structural unit [() + ()] is larger than 95 mol% of [() + () + ()], the melt fluidity will decrease and it will solidify during polymerization, and if it is smaller than 77 mol%, the heat resistance will be poor. Undesirable. In addition, the molar ratio of structural units ()/() is 75/25~
The ratio is 95/5, preferably 78/22 to 95/5, and more preferably 91/9 to 92/8. 75／
If it is less than 25 or greater than 95/5, the object of the present invention cannot be achieved due to poor heat resistance or poor fluidity. In addition, the structural unit () is essentially the structural unit [() +
()] is equimolar. Typical methods for producing the copolymerized polyester used in the present invention include the following methods, but in any of the methods, polymerization is carried out in a solid polydisperse state until part or all of it becomes a solid phase. Since it is desired to obtain an optically anisotropic liquid crystal polyester, it is preferable to carry out polymerization until substantially all of the polyester is in a uniform molten state, as in the examples of the present invention. (1) Acylated products of hydroxybenzoic acids such as p-acetoxybenzoic acid, diacylated products of aromatic dihydroxy compounds such as 4,4'-diacetoxybiphenyl, aromatic dicarboxylic acids such as terephthalic acid, and ethylene such as polyethylene terephthalate. A method for producing polyester from glycol and aromatic dicarboxylic acid by deacetic acid polymerization. (2) Polyesters made from aromatic dihydroxy compounds such as p-hydroxybenzoic acid and 4,4'-dihydroxybiphenyl, aromatic dicarboxylic acids such as acetic anhydride and terephthalic acid, and ethylene glycol and aromatic dicarboxylic acids such as polyethylene terephthalate. A method of producing by deacetic acid polymerization. Although these polycondensation reactions proceed without a catalyst,
It is sometimes preferable to add metal compounds such as stannous acetate, tetrabutyl titanate, sodium and potassium acetates, antimony trioxide, metallic magnesium, and the like. Furthermore, the melt viscosity of the copolymerized polyester used in the present invention is preferably 10 to 15,000 poise, particularly 20 to 15,000 poise.
5000 poise is more preferable. In addition, this melt viscosity is (liquid crystal starting temperature + 40℃)
The values were measured using a Koka type flow tester under the condition of a shear rate of 1000 (1/sec). On the other hand, the logarithmic viscosity of this copolyester is
The value measured in pentafluorophenol at a concentration of 0.1 g/dl at 60°C is 0.5 to 5 dl/g, and 1.0
~3.0 dl/g is particularly preferred. In addition, when polycondensing the copolymerized polyester used in the present invention, in addition to the components constituting the above structural units () to (), isophthalic acid, 3,3'-diphenyldicarboxylic acid, 2,2'-diphenyl Aromatic dicarboxylic acids such as dicarboxylic acid, aliphatic dicarboxylic acids such as adipic acid, azelaic acid, sebacic acid, dodecanedioic acid, alicyclic dicarboxylic acids such as hexahydroterephthalic acid, chlorohydroquinone, methylhydroquinone, 4,4' -Aromas such as dihydroxydiphenyl sulfone, 4,4'-dihydroxydiphenylpropane, 4,4'-dihydroxydiphenyl sulfide, 4,4'-dihydroxybenzophenone, 4,4'-dihydroxydiphenyl ether, etc. group diol, 1,4-butadiol, 1,6-hexanediol, neopentyl glycol, 1,4-cyclohexanediol,
Aliphatic and cycloaliphatic diols such as 1,4-cyclohexanedimethanol and aromatic hydroxycarboxylic acids such as m-hydroxybenzoic acid and 2,6-hydroxynaphthoic acid are used in small proportions that do not impair the purpose of the present invention. Further copolymerization can be carried out within the range of . The copolymerized polyester injection molded product of the present invention is usually made of the copolymerized polyester detailed above, and the cylinder temperature is above the liquid crystal start temperature and below 330°C, preferably above (liquid crystal start temperature + 10°C) and below 320°C, and the mold temperature is above 330°C. 10℃ or more and 150℃ or less, preferably 30℃ or more
Obtained by injection molding into three-dimensional molded products at temperatures below 120°C. The copolyester injection molded product of the present invention includes reinforcing materials such as glass fiber, carbon fiber, and asbestos, fillers, nucleating agents, pigments, antioxidants, stabilizers, plasticizers, lubricants, mold release agents, and flame retardants. Additives and other thermoplastics can be added to impart desired properties. The heat distortion temperature of the injection molded product of the present invention (load 18.6
Kg/cm ² ) is a value measured according to ASTM D648, and must be 150°C or higher, preferably 180°C or higher. The injection molded product obtained in this way is
Heat treatment can increase strength and may also increase modulus. This heat treatment involves placing the injection molded part in an inert atmosphere (e.g. nitrogen, argon, helium or water vapor).
Alternatively, it can be carried out by heat treatment in an oxygen-containing atmosphere (for example, air) at a temperature below the melting point of the polymer. This heat treatment may or may not be carried out under tension, and can be carried out for several tens of minutes to several days. <Example> The present invention will be further described below with reference to Examples. Example 1 P-acetoxybenzoic acid () in a test tube for polymerization
60.80 g (33.75X10 ^-2 mol), 12.16 g (4.5X10 ^-2 mol) of 4,4'-diacetoxybiphenyl (), 7.47 g (4.5X10 ^-2 mol) of terephthalic acid and polyethylene with an intrinsic viscosity of about 0.6 Terephthalate ()
12.97g (6.75X10 ^-2 mol) [()+()]/
[()+()+()] is 85 mol%, ()/(
)
were charged so that the molar ratio was 88/12, and acetic acid depolymerization was carried out under the following conditions. First, under nitrogen gas atmosphere at 250-300℃ and 0.2mmHg.
The pressure was reduced to 3.25 hours, and the polycondensation was completed. Almost the theoretical amount of acetic acid was distilled out, and a beige-colored polymer was obtained. Further, 5 batches of polymerization were performed under the same conditions, the polymer was recovered, and the polymer was pulverized using a pulverizer manufactured by Horai Co., Ltd. The theoretical structural formula of this polymer is as follows,
The elemental analysis results of the polyester showed good agreement with the theoretical values. l/m/n=75/10/15 In addition, this polyester was placed on the sample stage of a polarizing microscope and the temperature was raised to confirm the optical anisotropy.As a result, the liquid crystal start temperature was 264℃, which was good. It showed excellent optical anisotropy. This polyester was subjected to a Sumitomo Nestal injection molding machine, Promat 40/25 (manufactured by Sumitomo Heavy Industries, Ltd.), with a cylinder temperature of 300°C and a mold temperature of 30°C.
A test piece of 1/8" thick x 1/2" wide x 5" long, a mold notch of 1/8" thick x 2 1/2" long, and an impact test piece were prepared under the conditions of ℃.This test piece Toyo Baldwin Tensilon UTM−
The bending elastic modulus was measured using 100 at a strain rate of 1 mm/min and a span distance of 50 mm.
It was 10.2GPa. Izotsu impact value is 36Kg.
It showed a high value of cm/cm. Furthermore, when the heat distortion temperature of a 1/8" thick test piece was measured using a heat distortion temperature device manufactured by Toyo Seiki, it was 206°C (18.60 Kg/cm ² ). The logarithmic viscosity of this polymer was 1.34. dl/g, and the melt viscosity is 304℃ and shear rate of 1000 (1/s).
The fluidity was extremely good at 310 poise. Example 2 60.80 p-acetoxybenzoic acid in a polymerization test tube
g (33.75 x 10 ^-2 mol) () 4,4'-diacetoxybiphenyl () 12.16 g (4.5 x 10 ^-2 mol),
4,4'-diphenyldicarboxylic acid 10.89g
(4.5X10 ^-2 mol), polyethylene-4,4'-diphenylcarboxylate/polyethylene terephthalate copolymer with an intrinsic viscosity of 0.7 (molar ratio 6/4)
()16.04g (6.75×10 ^-2 mol) [()+
()]/[()+()+()] is 85 mol%,
A polyester having a liquid crystal initiation temperature of 258° C. was obtained by carrying out polycondensation under the same conditions as in Example 1 by preparing so that the molar ratio of ( )/( ) was 88/12. The theoretical structural formula of this polymer is as follows,
The elemental analysis results of the polyester showed good agreement with the theoretical values. l/m/n=75/10/15 This polyester was injection molded under the same conditions as in Example 1, and the mechanical properties and thermal properties of the resulting molded product were measured. As a result, the bending elastic modulus is 1/
At 8" thick, it was 10.5GPa, and the Izotsu impact value (mold notch) was also high at 38.3Kg・cm/cm.
Also, the heat distortion temperature of the 1/8" thick test piece is 200℃.
(18.56Kg/cm ² ). The logarithmic viscosity of this polymer is 1.48 dl/g, and the melt viscosity is 308°C at a shear rate of 1000 (1/sec).
It was 240 poise and had excellent fluidity. Comparative example 1 p-acetoxybenzoic acid () in a polymerization test tube
24.32g (13.5×10 ^-2 mol), hydroquinone diacetate () 26.19g (13.5×10 ^-2 mol), terephthalic acid 22.43g (13.5× ^{10 -2} mol), polyethylene terephthalate () 34.59g (18.0× 10 ^-2 mol) Structural unit [() + ()] is 60 mol% of the total,
()/() molar ratio is 50/50) and polycondensation was carried out according to the conditions of Example 1 to reach the liquid crystal initiation temperature.
A polyester at 251°C was obtained. Polyester was injection molded under the conditions of Example 1, and the mechanical properties and thermal properties of the resulting molded product were measured. As a result, the bending modulus is 1/8″ thick.
7.0GPa, the isot impact value (mold notch) is 25.5Kg・cm/cm, and the heat distortion temperature of 1/8″ thickness is 130℃ (18.56Kg/cm ² ), which is higher than the polyester of the present invention. The heat resistance was extremely poor. Examples 3 to 11, Comparative Examples 2 to 4 p-acetoxybenzoic acid (),
4,4'-diacetoxybiphenyl (-1), hydroquinone diacetate (-2), 2,6-
Diacetoxynaphthalene (-3), t-butylhydroquinone diacetate (-4), phenylhydroquinone diacetate (-5), 3,
3',5,5'-tetramethyl-4,4'-diacetoxybiphenyl (-6), terephthalic acid (-
1), 4,4'-diphenyldicarboxylic acid (-
2), 1,2-bis(phenoxy)ethane-4,
4'-dicarboxylic acid (-3), 1,2-bis(2
-chlorophenoxy)ethane-4,4'-dicarboxylic acid (-4), 2,6-naphthalene dicarboxylic acid (-5) (of which (-1) to (-6)
and polyethylene terephthalate () having an intrinsic viscosity of 0.60 were charged into a polymerization test tube and polymerized under the same conditions as in Example 1. Condensation reaction and injection molding were performed, and liquid crystal onset temperature, melt viscosity, logarithmic viscosity, mechanical properties, and thermal properties were measured. As is clear from Table 1, the polymer of the present invention had good fluidity, good flexural modulus and isot impact strength of injection molded products, and extremely excellent heat distortion temperature of 190°C or higher. . On the other hand, the polymer of Comparative Example 2 has almost the same fluidity and elastic modulus as the polymer of the present invention, but the heat distortion temperature is 58°C, which is significantly inferior in heat resistance. It was found that the polyester had poor mechanical properties, and its heat resistance was also inferior to that of the polyester of the present invention. On the other hand, the polymer of Comparative Example 4 had a melting point of 450°C or higher and could not be injection molded.

【table】

[Table] Examples 12-14 Add p-acetoxybenzoic acid () to a test tube for polymerization
60.80g (33.75 x 10 ^-2 mol), 4,4'-diacetoxybiphenyl () 12.16g (4.5 x 110 ^-2 mol),
Terephthalic acid 7.49 g (4.5 x 10 ^-2 mol) and 0.5
% concentration, polyethylene-2 with a logarithmic viscosity of 0.68 dl/g, measured in orthochlorophenol at 25°C.
6-naphthalene dicarboxylate (Example 12)
Or logarithmic viscosity 0.72dl/g, polyethylene-
1,2-bis(phenoxy)ethane-4,4'-dicarboxylate (Example 13) or
0.86 dl/g polyethylene-1,2-bis-(2
-Chlorphenoxy)ethane-4,4'-dicarboxylate (Example 14) in an amount of 6.75 x 10 ^-2 mol each, polymerization was carried out in the same manner as in Example 1, and the liquid crystal initiation temperature and melt viscosity of the obtained polymer were measured. did.
Then, injection molding evaluation was performed in the same manner as in Example 1. These results are shown in Table 2. Table 2 shows that these polyesters have good fluidity and excellent mechanical properties and heat resistance.

[Table] Example 15 p-acetoxybenzoic acid () 64.86g (36.00
×10 ^-2 mol), 4,4'-diacetoxybiphenyl () 9.14 g (3.38 × 10 ^-2 mol), terephthalic acid
5.61g (3.38×10 ^-2 mol) and intrinsic viscosity of approximately 0.6
Polyethylene terephthalate () 10.81g
(5.63×10 ^-2 mol) [()+()]/[()+
()+()] of 87.5 mol% and the molar ratio of ()/() of 91.4/8.6 were charged into a polymerization test tube in the same manner as in Example 1, except that the final polymerization temperature was 310°C.
Example 1 Acetic acid depolymerization was carried out in the same manner as in Example 1.
The same theoretical structural formula (however, l/m/n=80/
7.5/12.5) was obtained. The liquid crystal initiation temperature of this polyester was 292°C, and it exhibited good optical anisotropy. Further, injection molding was carried out in the same manner as in Example 1 except that this polymerization was carried out in 5 batches and the cylinder temperature was set at 310° C., and the physical properties were evaluated. bending modulus
It was found to have excellent mechanical and thermal properties, with an Izotsu impact strength of 9.2 GPa, an Izot impact strength of 40 Kg/cm, and a heat distortion temperature of 227°C (18.56 Kg/cm ² ). In addition, the logarithmic viscosity of this polymer is 1.49 dl/g, and the shear rate is
The fluidity was extremely good with 1000 poise at 1/sec. Example 16 100 parts by weight of the polymer obtained in Example 15 was dry blended with 43 parts by weight of glass fiber (chip strand length: 3 mm), and then mixed using a 30 mmφ twin screw extruder.
The mixture was melt-kneaded and pelletized at 310°C. The obtained pellets were injection molded under the same conditions as in Example 15.
Flexural modulus 12.4 GPa, Izotsu impact strength 7.8
It had excellent mechanical and thermal properties, with a heat distortion temperature of 245°C (18.56Kg/cm ² ). <Effects of the Invention> The copolymerized polyester injection molded product of the present invention exhibits good heat resistance and mechanical properties, and thus can be used in various applications such as metal-substitute plastic molded products.

Claims (1)

[Claims] 1 Consists of the following structural units () to (), where the structural unit [()+()] is [()+()+()]
77
~95 mol%, the structural unit () is [() + () +
()] is 23 to 5 mol% of the structural unit ()/
The logarithmic viscosity (measured in pentafluorophenol at a concentration of 0.1 g/dl) obtained by injection molding of an optically anisotropic liquid crystal polyester having a molar ratio of () from 75/25 to 95/5 is 0.5 to 5 dl/g. , a copolyester injection molded product with a heat distortion temperature (load of 18.56 kg/cm ² ) of 150°C or higher. (-O-R ₁ -O) - ... () (-O-CH ₂ CH ₂ -O) - ... () (-OC-R ₂ -CO) - ... () (However, R in the formula ₁ represents one or more groups selected from [Formula] [Formula] [Formula] [Formula] [Formula] [Formula], and R ₂ represents one or more groups selected from [Formula] [Formula] [Formula] [Formula] Represents one or more groups, and X represents a hydrogen atom or a chlorine atom.Also, the structural unit [()+()] and the structural unit () are substantially equimolar.)