JPH0717741B2 - Copolyester - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION <Industrial field of application> The present invention provides a polymer having a high degree of polymerization only by melt polymerization, and has an optical anisotropy, heat resistance and rigidity that can be molded by an ordinary molding machine.
The present invention relates to a copolyester capable of giving a molded article having excellent mechanical properties represented by impact resistance.

<Prior Art> In recent years, the demand for higher performance of plastics has increased more and more, and polymers having various new properties have been developed. Among them, optically anisotropic liquid crystal polymers have excellent mechanical properties. (JP-A-51-8395 and JP-A-49-72393).

<Problems to be Solved by the Invention> As this liquid crystal polymer, for example, a liquid crystal polymer obtained by copolymerizing polyethylene terephthalate with p-hydroxybenzoic acid is known (JP-A-49-72393). However, this polymer has drawbacks such as insufficient heat resistance and poor mechanical properties, and it has been found that a molded product satisfying both properties cannot be obtained from this polymer.
Moreover, it has been found that the amount of p-hydroxybenzoic acid is required to be 80 mol% or more in order to improve the heat resistance, but at this time solidification occurs because solidification occurs during the polymerization.

On the other hand, as a means for improving the fluidity of such a polymer, improving the melt moldability, and further improving the mechanical properties, for example, as disclosed in JP-A-51-8395, polyethylene is used. A method of copolymerizing terephthalate with p-acyloxybenzoic acid, a dicarboxylic acid and an aromatic diol has been proposed, and it has been found that the mechanical properties are improved but the heat resistance is insufficient as this method. On the other hand, as described in Japanese Patent Publication No. 47-47870, p
-Whole-aromatic polyester obtained by copolymerizing 4,4'-dihydroxybiphenyl and terephthalic acid with hydroxybenzoic acid has good heat resistance, but melt polymerization is difficult because of its softening temperature of 400 ° C or higher. It turned out that the property was not sufficiently satisfactory.

Therefore, the present invention can obtain a high degree of polymerization polymer only by the melt polymerization method, good optical anisotropy that can be molded by an ordinary molding machine,
The purpose is to obtain a copolyester having mechanical properties and heat resistance.

<Means for Solving Problems> As a result of intensive investigations by the present inventors to achieve the above object,
It has been found that a polyester obtained by reacting p-hydroxybenzoic acid with a specific aromatic diol and an aromatic dicarboxylic acid and a polyester formed from ethylene glycol and an aromatic dicarboxylic acid is a copolyester which preferably meets the above-mentioned object. Invented.

That is, the present invention comprises the following structural units (I) to (IV), and the structural unit [(I) + (II)] is [(I) + (II) +
90 mol% or more and 95 mol% or less of (III)], and the structural unit (III) is 5 mol% or more of [(I) + (II) + (III)]
Less than 10 mol% and a structural unit (I) / (II) molar ratio of 75/25 to 95/5 with an inherent viscosity of 0.5 (0.1 g / dl concentration, measured in pentafluorophenol at 60 ° C.). ~ 5dl / g, phenol and tetrachloroethane = 1: 1 (weight ratio)
The present invention provides an optically anisotropic copolyester which is substantially insoluble in the mixed solution.

_{O-R 1 -O ...... (II} ) O-CH 2 CH 2 -O ...... (III) OC-R 2 -CO ...... (IV) ( provided that R ₁ in the formula is To X represents a hydrogen atom or a chlorine atom. In addition, structural unit [(II) + (III)]
And structural unit (IV) are substantially equimolar. ) The structural unit (I) is a structural unit formed from p-hydroxybenzoic acid, and the structural unit (II) is a structural unit formed from 4,4'-dihydroxybiphenyl. Hydroquinone, t-butylhydroquinone, 3,3 ', 5,5'-up to about 25 mol% of the above hydroquinone
It can be replaced by an aromatic diol selected from tetramethyl-4,4'-dihydroxybiphenyl and phenylhydroquinone.

On the other hand, the structural unit (III) is a structural unit produced from ethylene glycol, the structural unit (IV) is terephthalic acid,
4,4'-diphenyldicarboxylic acid, 2,6-naphthalenedicarboxylic acid, 1,2-bis (phenoxy) ethane-4,4'-dicarboxylic acid, 1,2-bis (2-chlorophenoxy) ethane-4, It is a structural unit formed from an aromatic dicarboxylic acid selected from 4'-dicarboxylic acid. Of these, R ₂ is Is most preferred.

On the other hand, among the structural units (I) to (IV), the structural unit [(I) + (II)] is [(I) + (II) + (III)]
Is more than 90 mol% and 95 mol% or less.

The structural unit (III) is in the range of 5 mol% or more and less than 10 mol% of [(I) + (II) + (III)]. The structural unit [(I) + (II)] is 9 of [(I) + (II) + (III)]
When it is more than 5 mol%, the melt fluidity is lowered and it solidifies during the polymerization, and when it is 90 mol% or less, the heat resistance is not always sufficient. The molar ratio of structural unit (I) / (II) is 75 / 25-9.
5/5, preferably 78/22 to 95/5, more preferably 91
/ 9 to 92/8. When it is less than 75/25 or greater than 95/5, the homogeneity of the polymer is poor, and the heat resistance is poor or the fluidity is poor, so that the object of the present invention can be achieved. Can not.

Typical methods for producing the copolyester of the present invention include the following methods. In each case, a method of performing polymerization in a solid polydisperse state until a part or all of the solid phase is a homogeneous optical Since an anisotropic copolyester cannot be obtained, it is preferable to carry out polymerization until substantially all are in a uniform molten state as in the examples of the present invention.

(1) Acylated products of oxybenzoic acid such as p-acetoxybenzoic acid, diacylated products of aromatic dioxy compounds such as 4,4′-diacetoxybiphenyl, aromatic dicarboxylic acids such as terephthalic acid, and ethylene glycol such as polyethylene terephthalate And a polyester derived from an aromatic dicarboxylic acid by deacetic acid polymerization.

(2) Polyesters of aromatic dioxy compounds such as p-oxybenzoic acid and 4,4′-dioxybiphenyl, aromatic dicarboxylic acids such as acetic anhydride and terephthalic acid, and ethylene glycol such as polyethylene terephthalate and aromatic dicarboxylic acids A method for producing and by deacetic acid polymerization.

Although these polycondensation reactions proceed without a catalyst, it is sometimes preferable to add a metal compound such as stannous acetate, tetrabutyl titanate, sodium acetate and potassium acetate, antimony trioxide, or magnesium metal.

The melt viscosity of the copolyester of the present invention is 10 to 15,0.
00 poise is preferable, and 20 to 5,000 poise is particularly preferable.

The melt viscosity is a value measured by a Koka type flow tester under conditions of (liquid crystal starting temperature + 30 ° C) and a shear rate of 1,000 (1 / sec).

On the other hand, the logarithmic viscosity of this copolyester is 0.1 g / dl, and the value measured in pentafluorophenol at 60 ° C is
It is 0.5 to 5 dl / g, preferably 1.0 to 3.0 dl / g.

Further, the copolyester of the present invention is characterized in that it is substantially insoluble in a mixed liquid of phenol and tetrachloroethane.

When polycondensing the copolyester of the present invention, in addition to the components constituting the above structural units (I) to (IV), isophthalic acid, 3,3'-diphenyldicarboxylic acid, 3,4'-diphenyldicarboxylic acid Aromatic dicarboxylic acids such as 2,2'-diphenyldicarboxylic acid, aliphatic dicarboxylic acids such as adipic acid, azelaic acid, sebacic acid and dodecadioic acid, alicyclic dicarboxylic acids such as hexahydroterephthalic acid, 2,6- Dihydroxynaphthalene, chlorohydroquinone, methylhydroquinone, 4,4'-dihydroxydiphenylsulfone, 4,4'-dihydroxydiphenylpropane, 4,4'-dihydroxydiphenylsulfide
Aromatic diols such as 4,4′-dihydroxybenzophenone and 4,4′-dihydroxydiphenyl ether, 1,4-
Butanediol, 1-6-hexanediol, neopentyl glycol, 1,4-cyclohexanediol, 1,4-
Aliphatic and alicyclic diols such as cyclohexanedimethanol and aromatic oxycarboxylic acids such as m-oxybenzoic acid and 2,6-oxynaphthoic acid are further added in a small proportion within the range not impairing the object of the present invention. It can be copolymerized.

The copolymerized polyester of the present invention thus obtained can obtain a polymer having a high degree of polymerization only by a melt polymerization method, and exhibits good optical anisotropy, mechanical properties and heat resistance, and extrusion molding, injection molding, compression molding, blow molding, etc. It can be subjected to the usual melt-molding, and can be processed into fibers, films, three-dimensional molded products, containers, hoses and the like.

For the copolyester of the present invention, glass fiber, carbon fiber, reinforcing agents such as asbestos, fillers, nucleating agents, pigments,
Additives such as antioxidants, stabilizers, plasticizers, lubricants, release agents and flame retardants, and other thermoplastic resins can be added to impart desired properties.

The molded product thus obtained can be increased in strength and also in elastic modulus by heat treatment. This heat treatment can be performed by heat-treating the molded article in an inert atmosphere (for example, nitrogen, argon, helium, or steam) or 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 under tension,
It can be performed in several tens of minutes to several days.

<Examples> The present invention will be further described below with reference to Examples.

Example 1 68.10 g of p-acetoxybenzoic acid (I) was added to a polymerization test tube.
(37.80 x 10 ^-2 mol), 4,4'-diacetoxybiphenyl (II) 9.73 g (3.6 x 10 ^-2 mol), terephthalic acid 5.98 g
(3.6 x 10 ^-2 mol) and 6.92 g (3.6 x 10 ^-2 mol) of polyethylene terephthalate (III) with an intrinsic viscosity of about 0.6
([(I) + (II)] / [(I) + (II) + (III)]
Was 92 mol% and the molar ratio of (I) / (II) was 91.3 / 8.7), and deacetic acid polymerization was carried out under the following conditions.

First, after reacting in a nitrogen gas atmosphere at 250 to 330 ° C for 2.5 hours, the pressure was reduced to 0.2 mmHg at 300 ° C, and the reaction was continued for 3.25 hours to complete polycondensation. A beige polymer was obtained. Further, 5 batch polymerization was performed under the same conditions to recover the polymer, and the polymer was crushed by a crusher manufactured by Toho Co., Ltd.

The theoretical structural formula of this polymer is as follows, and the elemental analysis results of the polyester showed good agreement with the theoretical values.

The polyester was placed on the sample stage of a polarizing microscope and the temperature was raised to check the optical anisotropy.
The temperature was 309 ° C, indicating good optical anisotropy.

This polyester is applied to Sumitomo Nestal injection molding machine, Promat 40/25 (Sumitomo Heavy Industries, Ltd.), and the cylinder temperature is 325 ° C, and the mold temperature is 30 ° C. 1/8 "thickness x 1/2" width A 5x long test piece and a 1/8 "thick x 21/2" length mold notch and impact test piece were prepared. Using this Toyo Baldwin Tensilon UTM-100, the strain rate was 1mm. The flexural modulus was 12.1 GPa when the span distance was 50 mm, and the Izod impact value was as high as 26 kgcm / cm. The heat distortion temperature of the 1/8 ″ thick test piece was measured using the test piece and found to be 241 ° C. (18.56 kg / cm ² ).

This polymer had a logarithmic viscosity of 1.42 dl / g, a melt viscosity of 339 ° C. and a shear rate of 1,000 (1 / sec) of 150 poises, showing good fluidity. Further, this polymer was substantially insoluble in a mixed solution of phenol and tetrachloroethane in any proportion.

Example 2 A polymerization test tube was charged with 68.10 g (37.80 g) of p-acetoxybenzoic acid.
X10 ^-2 mol) (I), 4,4'-diacetoxybiphenyl (II) 9.73 g (3.6 x 10 ^-2 mol), 4,4'-diphenyldicarboxylic acid 8.71 g (3.6 x 10 ^-2 mol) , Polyethylene-4,4'-diphenyldicarboxylate / polyethylene terephthalate copolymer with an intrinsic viscosity of 0.7 (molar ratio 6/4)
(III) 8.56 g (3.6 × 10 ^-2 mol), ([(I) + (I
I)] / [(I) + (II) + (III)] is 92 mol%,
A (I) / (II) molar ratio of 91.3 / 8.7 was charged and polycondensation was performed under the same conditions as in Example 1 to obtain a polyester having a liquid crystal starting temperature of 302 ° C.

The theoretical structural formula of this polymer is as follows, and the elemental analysis results of the polyester showed good agreement with the theoretical values.

This polyester was molded under the same conditions as in Example 1 and the mechanical properties and thermal characteristics of the resulting molded product were measured. As a result, the bending elastic modulus was 12.1 GPa at 1/8 "thickness, and the Izod impact value (mold notch) was as high as 24.7 kgcm / cm. Also, the thermal deformation of the 1/8" thick test piece Temperature is 237 ℃ (1
It was 8.56 kg / cm ² ). The melt viscosity of this polymer is 33
The fluidity was excellent at 1,400 poise at a shear rate of 1,000 (1 / sec) at 2 ° C. Further, this polymer was substantially insoluble in a mixed solution of phenol and tetrachloroethane in any proportion.

Comparative Example 1 24.32 g of p-acetoxybenzoic acid (I) was added to a polymerization test tube.
(13.5 × 10 ^-2 mol), hydroquinone diacetate (I
I) 26.19 g (13.5 × 10 ^-2 mol), terephthalic acid 22.43 g (1
3.5 × 10 ^-2 mol), polyethylene terephthalate (III)
34.59 g (18.0 × 10 ^-2 mol), ([(I) + (II)] /
[(I) + (II) + (III)] is 60 mol%, (I) / (I
I) A molar ratio of 50/50) was charged and polycondensation was carried out according to the conditions of Example 1 to obtain a polyester having a liquid crystal starting temperature of 251 ° C.

This polyester was molded under the conditions of Example 1 and the mechanical properties and thermal characteristics of the molded product obtained were measured. As a result, the bending elastic modulus is 7.0 GPa at 1/8 ″ thickness, the Izod impact value (mold notch) is 25.5 kg · cm / cm, and the heat deformation temperature at 1/8 ″ thickness is 130 ° C (18.56 kg / cm ² ) and the heat resistance was extremely poorer than that of the polyester of the present invention.

Examples 3 to 11 and Comparative Examples 2 to 4 p-acetoxybenzoic acid (I), 4,4 'was added to a polymerization test tube.
-Diacetoxy biphenyl (II-1), hydroquinone diacetate (II-2), 2,6-diacetoxy naphthalene (II-3), t-butyl hydroquinone diacetate (II-4), phenyl hydroquinone diacetate (II
-5), 3,3 ', 5,5'-tetramethyl-4,4'-diacetoxybiphenyl (II-6), terephthalic acid (IV-
1), 4,4'-diphenyldicarboxylic acid (IV-2), 1,2
-Bis (phenoxy) ethane-4,4'-dicarboxylic acid (I
V-3), 1,2-bis (2-chlorophenoxy) ethane-
4,4'-dicarboxylic acid (IV-4), 2,6-naphthalenedicarboxylic acid (IV-5) (of which (II-1) to (II-6)
And the components (IV-1) to (IV-5) are added in the same number of moles) and polyethylene terephthalate (III) having an intrinsic viscosity of 0.60 is charged into a polymerization test tube, and Example 1 is used.
The polycondensation reaction was carried out under the same conditions as above, and the liquid crystal starting temperature, melt viscosity, logarithmic viscosity, mechanical properties and thermal characteristics were measured. First
As is clear from the table, the polymer of the present invention had good fluidity, good flexural modulus and Izod impact strength, and a very high heat distortion temperature of 190 ° C or higher. On the other hand, the polymer of Comparative Example 2 has substantially the same fluidity and elastic modulus as the polymer of the present invention, but the heat distortion temperature is 58 ° C. and the heat resistance is significantly poor, and the polymer of Comparative Example 3 has a fluidity. It was found to be poor, mechanical properties were significantly inferior, and heat resistance was inferior to 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 molded.

Examples 12-14 p-acetoxybenzoic acid (I), 68.10 g in a test tube for polymerization.
(37.80 x 10 ^-2 mol), 4,4'-diacetoxybiphenyl (II) 9.73 g (3.6 x 10 ^-2 mol), terephthalic acid 5.98 g
(3.6 × 10 ⁻² mol) and 0.5% concentration, 25 ° C., polyethylene-2,6-naphthalenedicarboxylate with an inherent viscosity of 0.68 dl / g measured in orthochlorophenol (Example 1
2) or polyethylene-1,2-bis (phenoxy) ethane-4,4'-dicarboxylate having an inherent viscosity of 0.72 dl / g (Example 13) or polyethylene-1,2 having an inherent viscosity of 0.86 dl / g. -Bis (2-chlorophenoxy) ethane-4,4'-
3.60 × 10 ^-2 each of dicarboxylate (Example 14)
Molar amount Charged polymerization was carried out in the same manner as in Example 1 to measure the liquid crystal initiation temperature, melt viscosity and logarithmic viscosity of the obtained polymer. Then, injection molding evaluation was performed in the same manner as in Example 1.

The results are shown in Table 2.

It can be seen from Table 2 that these polyesters have good fluidity and excellent mechanical properties and heat resistance.

All the polymers were insoluble in a mixed solution of phenol and tetrachloroethane at any mixing ratio.

Comparative Example 5 p-acetoxybenzoic acid (I), 64.13 g, in a test tube for polymerization.
(35.6 × 10 ^-2 mol), hydroquinone diacetate (I
I) 8.64 g (4.45 × 10 ^-2 mol), terephthalic acid 7.39 g (4.4
× 5 × 10 ^-2 mol), polyethylene terephthalate (II
I) 8.55 g (4.45 × 10 ^-2 mol) ([(I) + (II)] /
[(I) + (II) + (III)] is 90 mol%, (I) / (I
I) A molar ratio of 89/11) was charged and the polymerization was carried out in the same manner as in Example 1. However, the polymer solidified during the polymerization, and the polymerization could not be carried out in a uniform molten state. Moreover, the optical anisotropy of the obtained polymer could not be confirmed.

<Effects of the Invention> The copolyester of the present invention can obtain a molded product having a high degree of polymerization and good heat resistance and mechanical properties only by the melt polymerization method. Can be used for various purposes.

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Claims (1)

[Claims] 1. The following structural units (I) to (IV), wherein the structural unit [(I) + (II)] is [(I) + (II) + (II
More than 90 mol% and not more than 95 mol% of the structural unit (II)
I) is 5 mol% or more and less than 10 mol% of [(I) + (II) + (III)], and the molar ratio of structural unit (I) / (II) is 75.
/ 25 to 95/5, logarithmic viscosity (measured in pentafluorophenol at 0.1g / dl concentration, 60 ° C) of 0.5 to 5dl / g, practically insoluble in a mixture of phenol and tetrachloroethane Is an optically anisotropic copolyester. _{O-R 1 -O ...... (II} ) O-CH 2 CH 2 -O ...... (III) OC-R 2 -CO ...... (IV) ( provided that R ₁ in the formula is , R ₂ is X represents a hydrogen atom or a chlorine atom. In addition, structural unit [(II) + (III)]
And structural unit (IV) are substantially equimolar. )