JP2515744B2 - Heat resistant aromatic polyester - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION <Industrial field of application> The present invention provides a molded product that can be melt-molded at 400 ° C or lower and has excellent mechanical properties and optical anisotropy with a glass transition temperature of 140 ° C or higher. The present invention relates to a novel heat-resistant aromatic polyester obtained.

<Prior art> In recent years, the demand for higher performance of plastics has been increasing, and many polymers having various new properties have been developed and put on the market. A liquid crystal polymer having optical anisotropy has attracted attention because it has excellent mechanical properties.

As this liquid crystal polymer, a wholly aromatic polyester is widely known, for example, a homopolymer and a copolymer of p-hydroxybenzoic acid are known. However, since the melting point of the p-hydroxybenzoic acid homopolymer and copolymer is too high to be melt-molded, various components are copolymerized with p-hydroxybenzoic acid,
A method for lowering the melting point has been studied, for example, a method for copolymerizing phenylhydroquinone, terephthalic acid and / or 2,6-naphthalenedicarboxylic acid with p-hydroxybenzoic acid (published patent publication No. 55-500215), p- Method for copolymerizing hydroxybenzoic acid with 2,6-dihydroxynaphthalene and terephthalic acid (JP-A-54-50594) and method for copolymerizing p-hydroxybenzoic acid with 2,6-dihydroxyanthraquinone and terephthalic acid (U.S. Patent No. 4,
224,433), a method of copolymerizing p-hydroxybenzoic acid with 4,4'-dihydroxybiphenyl and terephthalic acid and isophthalic acid (JP-B-57-24407, 60-25046), terephthalic acid with phenylhydroquinone Method for copolymerizing t-butyl hydroquinone (US Pat. No. 4,238,600
No.), a method of copolymerizing terephthalic acid with a nucleus-substituted phenylhydroquinone and hydroquinone (US Pat. No. 4,15
No. 3,779) has been proposed.

On the other hand, hydroxybenzoic acid, dihydroxybenzene,
A polyester comprising cyclohexanedicarboxylic acid is known from Japanese Patent Publication No. 59-31592, but the use of t-butylhydroquinone as dihydroxybenzene is not described in the specification at all.

<Problems to be solved by the invention> However, although many of the aromatic polyesters obtained by these methods have relatively low melting points of 400 ° C or lower, the elastic modulus of the spun yarn is still insufficient. However, due to insufficient heat resistance or poor fluidity, further higher elastic modulus and higher heat resistance are desired.

Therefore, as a result of intensive investigations by the present inventors for the purpose of obtaining a melt-moldable aromatic polyester having excellent heat resistance and fluidity, an aromatic polyester composed of p-hydroxybenzoic acid, t-butylhydroquinone, and terephthalic acid. By substituting a part of the t-butyl hydroquinone and / or terephthalic acid with an aromatic hydroxy compound such as hydroquinone or an aromatic dicarboxylic acid such as isophthalic acid, a melt-moldable aromatic polyester preferably satisfying the above object can be obtained. They have found that they can be obtained and have completed the present invention.

<Means for Solving Problems> That is, the present invention comprises the following structural units (I) to (V), wherein the structural unit (I) is [(I) + (II) + (III)].
Structural unit [(II) + (III)] accounts for 45-20 mol% of [(I) + (II) + (III)],
Structural unit (II) / (III) molar ratio 1-5 and (IV)
The molar ratio of / (V) is 1 to 5, [(II) + (III)] and [(IV) + (V)] are substantially equimolar, and 4,4'-
Provided is a heat-resistant aromatic polyester which does not contain a diphenyldicarbonyl unit and has a melt viscosity of (liquid crystal starting temperature + 60 ° C) and a shear rate of 3,000 (1 / sec) of 10 to 15,000 poise. It is a thing.

O-X-O (III) (X is Represents one or more groups selected from Represents one or more groups selected from Where X is In the case of one or more groups selected from In the aromatic polyester of the present invention, the structural unit (I) is the structural unit of the polyester produced from p-hydroxybenzoic acid, and the structural unit (II) is the structural unit produced from t-butylhydroquinone. (III) is t-
Aromatic dihydroxy compounds such as butyl hydroquinone, hydroquinone, 4,4'-dihydroxydiphenyl ether, bisphenol A, bisphenol S, 3,3 ', 5,5'-tetramethyl-4,4'-dihydroxydiphenyl (IV) is a structural unit produced from terephthalic acid, (V) is an isophthalic acid, terephthalic acid, hexahydroterephthalic acid, 1,2-bis (phenoxy) ethane-4,4'- Dicarboxylic acid, 1,2-bis (2-chlorophenoxy) ethane-4,4'-dicarboxylic acid, 2,6-
A structural unit formed from a dicarboxylic acid such as dicarboxynaphthalene is shown.

The structural unit (I) is [(I) + (II) + (III)]
If it exceeds 80 mol% or less than 45 mol%, the fluidity is poor and the object of the present invention cannot be achieved. The most preferable composition is structural unit (I) [(I) + (II) + (II
I)] is 60 to 75 mol%.

On the other hand, the structural unit (II) / (III) or (IV) /
When the molar ratio of (V) is less than 1 or more than 5, it is impossible to obtain a heat-resistant high-elasticity molded product due to poor fluidity, and (II) / (III) as in the present invention. The object of the present invention can be achieved only when the molar ratio of) is 1 to 5 and the molar ratio of (IV) / (V) is 1 to 5. Among them, the most preferable composition is a (II) / (III) molar ratio of 1 to 4 and a (IV) / (V) molar ratio of 1 to 4.

The aromatic polyester of the present invention can be produced according to a conventional polyester polycondensation method, and the production method is not particularly limited, but typical production methods include, for example, the following (1) to
(4) method.

(1) A method for producing an aromatic dihydroxy compound such as p-acetoxybenzoic acid or t-butylhydroquinone diacetate and a dicarboxylic acid such as terephthalic acid by a deacetic acid polycondensation reaction.

(2) A method of producing from an aromatic dihydroxy compound such as p-hydroxybenzoic acid or t-butylhydroquinone, a dicarboxylic acid such as terephthalic acid, and acetic anhydride by a deacetic acid polycondensation reaction.

(3) A method for producing from a phenyl ester of p-hydroxybenzoic acid and an aromatic dihydroxy compound such as t-butylhydroquinone and a diphenyl ester of a dicarboxylic acid such as terephthalic acid by dephenol polycondensation.

(4) After dicarboxylic acid such as p-hydroxybenzoic acid and terephthalic acid is reacted with a desired amount of diphenyl carbonate to form each diphenyl ester, t-
A method for producing by a dephenol polycondensation reaction by adding an aromatic dihydroxy compound such as butyl hydroquinone.

Typical catalysts used in the polycondensation reaction are metal compounds such as stannous acetate, tetrabutyl titanate, lead acetate, antimony trioxide, magnesium, sodium acetate, potassium acetate and trisodium phosphate. Effective during polycondensation.

The melt viscosity of the aromatic polyester of the present invention is 10 to
15,000 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 the condition of (liquid crystal starting temperature + 60 ° C) and shear rate of 3,000 (1 / sec). The liquid crystal onset temperature is the temperature at which shear stress is applied under a polarizing microscope to give a milky white color.

When polycondensing the aromatic polyester of the present invention, 4,4'-dihydroxybiphenyl, resorcin, chlorohydroquinone, methylhydroquinone, phenylhydroquinone, other than the components constituting the above (I) to (V),
Aromatic dihydroxy compounds such as 2,6-dihydroxynaphthalene and 2,7-dihydroxynaphthalene, 3,3'-diphenyldicarboxylic acid, 3,4'-diphenyldicarboxylic acid, 2,2'-diphenyldicarboxylic acid Aromatic dicarboxylic acids, m-hydroxybenzoic acid, 2,6-hydroxynaphthoic acid and other aromatic hydroxycarboxylic acids and p
-Aminophenol, p-aminobenzoic acid and the like can be further copolymerized in a small proportion so long as the object of the present invention is not impaired.

The aromatic polyester thus obtained has a melting point of 40.
As low as 0 ° C or less, it can be used for ordinary melt molding such as extrusion molding, injection molding, compression molding, blow molding, and can be processed into fibers, films, three-dimensional molded products, containers, hoses, etc. .

In addition, at the time of molding, the aromatic polyester of the present invention, glass fiber, carbon fiber, reinforcing agents such as asbestos,
Add additives such as fillers, nucleating agents, pigments, antioxidants, stabilizers, plasticizers, lubricants, mold release agents and flame retardants, and other thermoplastic resins to give desired properties to molded articles. be able to.

The molded product thus obtained can have its strength increased by heat treatment, and its elastic modulus can also be increased in many cases.

This heat treatment causes the molded article to be placed in an inert atmosphere (eg, nitrogen,
It can be carried out by heat treatment in argon, helium or water vapor) or in an oxygen-containing atmosphere (eg air) at a temperature below the melting point of the polymer. This heat treatment may or may not be under tension and can be carried out for a few minutes to a few days.

The molded product obtained from the novel aromatic polyester of the present invention has good optical anisotropy due to its parallel molecular arrangement, and has extremely excellent heat resistance and mechanical properties.

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

Example 1 24.1 parts (1.34) of p-acetoxybenzoic acid was added to a polymerization test tube.
× 10 ^-1 mol), t-butyl hydroquinone diacetate
16.5 parts (0.66 × 10 ^-1 mol), terephthalic acid 7.3 parts (0.44
X 10 ^-1 mol), isophthalic acid 3.65 parts (0.22 x 10 ^-1 mol)
Was charged, and deacetic acid polymerization was carried out under the following conditions.

First, after reacting in a nitrogen gas atmosphere at 250 to 360 ° C. for 3 hours, the pressure was reduced to 2.0 mmHg at 360 ° C. and further heated for 0.6 hours to complete the polycondensation. was gotten.

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 as shown in Table 1.

1 / m / n / o = 67/33/22/11 In addition, when this polyester was placed on the sample stage of a polarizing microscope and the air anisotropy was applied to confirm it,
Good optical anisotropy was exhibited at 0 ° C or higher.

Further, the thermal characteristics were measured with a differential scanning calorimeter (Perkin Elmer II type), and it was found that the glass transition temperature was 166 ° C and that the glass had good heat resistance.

This polyester was applied to a Koka type flow tester and spun at a spinning temperature of 330 ° C. with a spinneret hole diameter of 0.3 mmφ and wound at 17 m / min to obtain a spun yarn of 0.07 mmφ. This spun yarn was manufactured using Toyo Baldwin Co., Ltd.'s Leovibron DDV-II-EA at a frequency of 110 Hz, a heating rate of 2 ° C./min, and a check distance of 40 m.
When the elastic modulus was measured at m, it was 57 GPa at 30 ° C.

The melt viscosity of this polymer is 330 ° C and the shear rate is 3000.
(1 / sec) was 900 poise.

Example 2 Deacetic acid polymerization was carried out under the following conditions except that 3.7 parts (0.22 × 10 ^-1 mol) of transcyclohexanedicarboxylic acid was used instead of isophthalic acid in Example 1.

First, after reacting in a nitrogen gas atmosphere at 250 to 330 ° C for 3.5 hours, the pressure was reduced to 1.0 mmHg and further heated at 330 to 340 ° C for 1.0 hour to complete polycondensation. A polymer was obtained.

The theoretical structural formula of this polymer is as follows, and the elemental analysis of the polyester showed good agreement with the theoretical values as shown in Table 2.

1 / m / n / o = 67/33/22/11 In addition, when this polyester was placed on the sample stage of a polarizing microscope and the air anisotropy was applied to confirm it,
Good optical anisotropy was exhibited at 0 ° C or higher.

Further, the thermal characteristics were measured with a differential scanning calorimeter (Perkin Elmer II type), and it was found that the glass transition temperature was 157 ° C. and that the glass had good heat resistance.

This polyester was applied to a Koka type flow tester and spun at a spinning temperature of 330 ° C. and a spinneret hole diameter of 0.3 mmφ, and wound at 49 m / min to obtain a spun yarn of 0.06 mmφ. The elastic modulus of this spun yarn was measured in the same manner as in Example 1 using Rheovibron DDV-II-EA manufactured by Toyo Baldwin Co., Ltd., and the elastic modulus was 55 GPa at 30 ° C.
Met. In addition, the peak temperature of the moving point loss was 157 ° C, indicating good heat resistance.

This polymer has a melt viscosity of 310 ° C and a shear rate of 3000 (1 /
970 poise in seconds).

Examples 3 to 14 p-acetoxybenzoic acid (I), t-butyl hydroquinone diacetate (II), hydroquinone diacetate (III), 4,4'-diacetoxy diphenyl ether (IV), bisphenol A diacetate. (V), bisphenol S diacetate (VI), 3,3 ', 5,5'-tetramethyl-4,4'-dihydroxybiphenyl (VII), terephthalic acid (VIII), isophthalic acid (IX), 1,4-transcyclohexanedicarboxylic acid (X), 1,2-bis (phenoxy) ethane-4,4'-dicarboxylic acid (XI), 1,2-
Bis (2-chlorophenoxy) ethane-4,4'-dicarboxylic acid (XII), 2,6-naphthalenedicarboxylic acid (XIII)
(II) to (VII) components and (VIII) to (XII
The same number of moles of the component (I) was used, the mixture was charged into a polymerization test tube, and a polycondensation reaction was performed under the same conditions as in Examples 1 and 2 to measure the liquid crystal starting temperature and the melt viscosity.

It can be seen from Table 3 that the polyesters of the present invention (Examples 3 to 14) have a low liquid crystal initiation temperature, a low melt viscosity, and a high glass transition temperature despite the rigid structure.

Comparative Example p-acetoxybenzoic acid 24.1 parts (1.34 x 10 ^-1 mol) and t-butyl hydroquinone diacetate 16.5 parts (0.66 x
10 ^-1 mol) and 11.0 parts of terephthalic acid (0.66 x 10 ^-1 mol) were charged into a polymerization test tube and placed under a nitrogen gas atmosphere at 250
When the reaction was carried out at ˜360 ° C. for 3 hours, the fluidity was poor and the polymer solidified and no tough polymer was obtained.

Comparative Example 2 p-acetoxybenzoic acid 24.1 parts (1.34 × 10 ^-1 mol) and chlorohydroquinone diacetate 10.1 parts (0.44 × 10 ^-1)
Mol), 4,4′-diacetoxydiphenyl ether 6.3 parts (0.22 × 10 ⁻¹ mol) and terephthalic acid 11.0 parts (0.66 ×
10 ^-1 mol) was charged into a polymerization test tube and polymerized in the same manner as in Example 1.

The liquid crystal starting temperature of the obtained polymer was 310 ° C., spinning was carried out at 360 ° C. as in Example 1, and the peak temperature of the dynamic loss was measured with Rheovibron of the obtained spun yarn (fiber diameter 0.16 mm). As a result, it was a low value of 110 ° C.

<Effects of the Present Invention> The heat-resistant aromatic polyester of the present invention can be melt-molded and a molded product having good heat resistance can be obtained, and thus can be used for various applications such as engineering plastics.

Claims (1)

(57) [Claims] 1. The following structural units (I) to (V), wherein the structural unit (I) is [(I) + (II) + (III)] 55-80.
Mol%, structural unit [(II) + (III)] is [(I) + (I
I) + (III)] in the structural unit (II)
The molar ratio of / (III) is 1 to 5 and the molar ratio of (IV) / (V) is 1 to 5, [(II) + (III)] and [(IV) +
(V)] is substantially equimolar, does not contain 4,4′-diphenyldicarbonyl units, has a melt viscosity (liquid crystal starting temperature + 60 ° C.) and a shear rate of 3,000 (1 / sec). ~ 15,
A heat-resistant aromatic polyester characterized by being 000 poise. O-X-O (III) (However, in the formula (III), X is Y is one or more groups selected from And one or more groups selected from Where X is In the case of one or more groups selected from (Excluding combinations that are