JP3094504B2 - Liquid crystal polyester composition - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a liquid crystal polyester composition having low mechanical anisotropy.

[0002]

2. Description of the Related Art In recent years, there has been an increasing demand for higher performance of plastics, and a number of polymers having various novel properties have been developed. Among them, optically anisotropic liquid crystal polymers have excellent chemical resistance and Attention has been paid to its mechanical properties (JP-A-51-8395, JP-A-49-8395).
-72393).

As the liquid crystal polymer, for example, p
Liquid crystal polyester obtained by copolymerizing hydroxybenzoic acid with polyethylene terephthalate (Japanese Patent Laid-Open No. 49-72393).
And liquid crystal polyesters obtained by copolymerizing p-hydroxybenzoic acid with 4,4'-dihydroxybiphenyl, terephthalic acid, and isophthalic acid (JP-A-57-24407).

Japanese Unexamined Patent Publication (Kokai) No. 62-143964 discloses that a special polyester such as a polyester which forms an anisotropic molten phase which cannot be further chain-grown by heating is replaced with an epoxy such as a bisphenol type epoxy compound. It is described that a compound is compounded to improve hydrolysis resistance and heat resistance.

However, in general, thermotropic liquid crystal polyester has a problem that the mechanical anisotropy represented by the dimensional accuracy of a molded article is large.

As a method of reducing the mechanical anisotropy, there is known a method of blending an isotropic thermoplastic polymer (such as polyethylene terephthalate) with a thermotropic liquid crystal polyester (Japanese Unexamined Patent Publication (Kokai) No. 1-1990). 252657
No.).

[0007]

However, when the isotropic thermoplastic polymer is blended with the thermotropic liquid crystal polyester, the excellent mechanical and
It was found that thermal properties often deteriorated.

Therefore, the present invention solves the above-mentioned problems,
An object is to obtain a liquid crystal polyester composition having low mechanical anisotropy.

[0009]

The present inventors have conducted intensive studies to solve the above-mentioned problems, and as a result, a resin composition obtained by adding a specific epoxy compound to thermotropic liquid crystal polyester satisfies the above-mentioned problems. It has been found that the present invention has been completed.

That is, the present invention relates to (B) an epoxy compound represented by the following structural formula (1): 0.01 to 2 parts per 100 parts by weight of the thermotropic liquid crystal polyester.
This is a liquid crystal polyester composition containing 0 parts by weight and (C) 0 to 200 parts by weight of a filler.

[0011]

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The thermotropic liquid crystal polyester used in the present invention is a polyester which shows a liquid crystal in a molten state, and specifically includes an aromatic oxycarbonyl unit, an aromatic dioxy unit, an aromatic dicarbonyl unit, an ethylenedioxy unit and the like. And polyesters composed of units selected from the group consisting of:

In particular, the following structural units (I), (II),
Liquid crystal polyesters consisting of (IV) or (I), (II), (III) and (IV) are preferred, especially (I), (I)
Liquid crystal polyesters comprising I), (III) and (IV) are preferred.

[0014]

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(Where R ₁ in the formula is

[0016]

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And R ₂ represents one or more groups selected from

[0018]

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Represents a group selected from The structural unit (IV) is substantially equimolar to the sum of the structural units (II) and (III) . )

The structural unit (I) is a structural unit of a polyester formed from p-hydroxybenzoic acid, and the structural unit (II) is 4,4'-dihydroxybiphenyl,
3 ', 5,5'-tetramethyl-4,4'-dihydroxybiphenyl, hydroquinone, t-butylhydroquinone, phenylhydroquinone, 2,6-dihydroxynaphthalene, 2,7-dihydroxynaphthalene, 2,2
-Bis (4-hydroxyphenyl) propane and 4,
A structural unit generated from 4'-dihydroxydiphenyl ether, a structural unit (III) a structural unit generated from ethylene glycol, a structural unit (IV) a terephthalic acid,
Isophthalic acid, 4,4′-diphenyldicarboxylic acid,
Structural unit formed from one or more aromatic dicarboxylic acids selected from 2,6-naphthalenedicarboxylic acid, 1,2-bis (phenoxy) ethane 4,4'-dicarboxylic acid, and 4,4'-diphenyl ether dicarboxylic acid Are respectively shown.

When the structural unit (III) is included, the structural unit formed from 4,4′-dihydroxybiphenyl is the structural unit (III). When the structural unit (III) is not included, the structural unit (I) is 4 Structural units formed from 4,4'-dihydroxybiphenyl and 2,6-dihydroxynaphthalene are preferable, and the structural unit (IV) is preferably a structural unit formed from terephthalic acid.

The copolymerization amount of the above structural units (I), (II), (III) and (IV) is arbitrary. However, the following copolymerization amount is preferred from the viewpoint of fluidity. That is, when the structural unit (III) is included, the structural unit (I) and the structural unit (I)
And the sum of (II) is the sum of the structural units (I), (II) and (II)
It is preferably from 60 to 95 mol%, particularly preferably from 85 to 93 mol%, based on the total of I) . Further, the structural unit (III) includes structural units (I), (II) and
It is preferably from 40 to 5 mol%, particularly preferably from 15 to 7 mol%, based on the total of (III) . Further, the molar ratio of the structural units (I) and (II) [(I) / (I
I)] is preferably 75/25 to 95/5, and the conceptual unit (I)
V) is substantially equimolar to the sum of the structural units (II) and (III) . On the other hand, when the above structural unit (III) is not contained, (I) is based on the sum of structural units (I) and (II).
Preferably 40 to 90 mol% Te, particularly preferably 60 to 88 mol%, the structural unit (IV) is substantially equimolar with the structural unit (II).

When the preferred thermotropic liquid crystal polyester is subjected to polycondensation, the above (I), (II),
In addition to the components constituting (III) and (V), 3,3 ′
-Aromatic dicarboxylic acids such as diphenyldicarboxylic acid, 3,4'-diphenyldicarboxylic acid and 2,2'-diphenyldicarboxylic acid, alicyclic dicarboxylic acids such as hexahydroterephthalic acid, resorcinol, chlorohydroquinone, methylhydroquinone, bis Aromatic dihydroxy compounds such as (4-hydroxyphenyl) sulfone and their ethylene oxide adducts, 1,4-butanediol, 1,6-hexanediol, neopentyl glycol, 1,4-cyclohexanediol, 1,4- Aliphatic, alicyclic diols such as cyclohexanedimethanol and aromatic hydroxycarboxylic acids such as m-oxybenzoic acid, 6-hydroxy-2-naphthoic acid and p-
Aminophenol, p-aminobenzoic acid and the like may be further copolymerized in a small proportion.

The melt viscosity is usually 10,000 poise or less, preferably 6,000 poise or less, and more preferably 4,000 poise or less.

The melt viscosity is expressed as (melting point (Tm) +1
0 ° C.) and a shear rate of 1,000 (1 / second) under the conditions of a Koka flow tester.

The method for producing the thermotropic liquid crystal polyester (A) in the present invention is not particularly limited, and it can be produced according to a known polyester polycondensation method.

For example, when the above structural unit (III) is not contained, the following production methods (i) and (ii) are preferably used, and when the above structural unit (III) is contained, the production method (v) is preferably used.

(I) p-acetoxybenzoic acid, 4,4 '
-A method of producing from a diacylated aromatic dihydroxy compound such as diacetoxybiphenyl and an aromatic dicarboxylic acid such as terephthalic acid by a deacetic acid polycondensation reaction.

(Ii) p-hydroxybenzoic acid, 4,4 '
A method of reacting an aromatic dihydroxy compound such as dihydroxybiphenyl and an aromatic dicarboxylic acid such as terephthalic acid with acetic anhydride to acylate a phenolic hydroxyl group, followed by production by a deacetic acid polycondensation reaction (however,
As for 2,6-dihydroxynaphthalene, it is preferable to use 2,6-diacetoxynaphthalene).

(Iii) A method of producing from a phenyl ester of p-hydroxybenzoic acid, an aromatic dihydroxy compound such as 4,4'-dihydroxybiphenyl and a diphenyl ester of an aromatic dicarboxylic acid such as terephthalic acid by a dephenol polycondensation reaction. .

(Iv) A desired amount of diphenyl carbonate is reacted with an aromatic dicarboxylic acid such as p-hydroxybenzoic acid and terephthalic acid to form a diphenyl ester, and then an aromatic dihydroxy compound such as 4,4'-dihydroxybiphenyl And a production method by a dephenol polycondensation reaction.

(V) The method of (i) or (ii) in the presence of an oligomer or polymer comprising ethylene glycol and an aromatic dicarboxylic acid or a bis (β-hydroxyethyl) ester of an aromatic dicarboxylic acid.

According to the method (v), the oligomer or polymer comprising ethylene glycol and aromatic dicarboxylic acid or the above bis (β-hydroxyethyl) ester is
It is considered that a thermotropic liquid crystal polyester containing the above structural unit (III) is randomly incorporated into a molecular chain by a transesterification reaction.

At the time of the polymerization reaction, a catalyst may be used if necessary. As a catalyst used for the polycondensation reaction, acetic acid
Metal compounds such as tin, tetrabutyl titanate, potassium acetate, antimony trioxide, magnesium, sodium acetate, and zinc acetate are typical, and are particularly effective for dephenol polycondensation.

Some of the thermotropic liquid crystal polyesters (A) in the present invention can be measured for intrinsic viscosity in pentafluorophenol. In this case, the measurement was performed at a concentration of 0.1 g / dl at 60 ° C. 0.5d in value
It is preferably at least 1 / g, particularly preferably 0.5 to 3.0 dl / g when containing the structural unit (III), and particularly preferably 1.0 to 15.0 dl / g when not containing the structural unit (III).

Next, the epoxy compound (B) used in the present invention
Is a compound represented by the following structural formula (1), and is known to be added to a specific liquid crystal polyester for the purpose of improving the hydrolysis resistance and heat resistance of the thermotropic liquid crystal polyester. Epoxy compounds such as compounds (JP-A-62-14396)
No. 4) has a small effect on improving anisotropy, so that it is difficult to achieve the object of the present invention.

[0037]

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The epoxy compound is added in an amount of 0.01 to 20 parts by weight, preferably 0.05 to 15 parts by weight, more preferably 0.1 to 10 parts by weight, based on 100 parts by weight of the thermotropic liquid crystal polyester (A). Department. If the amount exceeds 20 parts by weight, the fluidity becomes poor and the mechanical properties are adversely affected. If the amount is less than 0.01 part by weight, no substantial effect is obtained, which is not preferable.

The filler (C) used in the present invention includes inorganic fibers such as glass fiber, alumina fiber, silicon carbide fiber, ceramic fiber, asbestos fiber, stone fiber, metal fiber (for example, stainless steel fiber) and carbon fiber. Fibrous fillers such as silicates such as wollastenite, sericite, kaolin, clay, bentonite, asbestos, talc, alumina silicate, metal oxides such as alumina, silicon oxide, magnesium oxide, zirconium oxide, titanium oxide, and carbon dioxide Carbonates such as calcium, magnesium carbonate and dolomite, sulfates such as calcium sulfate and barium sulfate, glass beads, boron nitride,
And powdery or granular fillers such as silicon carbide and Saroyan, which may be hollow (eg,
Hollow glass fiber, glass micro balloon, shirasu balloon, carbon balloon, etc.). If necessary, the above-mentioned filler may be pretreated with a coupling agent such as a silane-based or titanium-based taste before use.

The amount of the filler (C) is in the range of 0 to 200 parts by weight, preferably 10 to 15 parts by weight, per 100 parts by weight of the thermotropic liquid crystal polyester (A).
0 parts by weight. If the amount exceeds 200 parts by weight, the mechanical properties and moldability are significantly reduced, which is not preferable.

In the present invention, the combined use of an organic flame retardant, a brominated polystyrene, a brominated epoxy compound, a brominated polycarbonate, a brominated pophenylene ether or the like with the epoxy compound of the present invention reduces the mechanical anisotropy. Can be further increased.

The liquid crystal polyester composition of the present invention contains an antioxidant and a heat stabilizer (for example, hindered phenol, hydroquinone, phosphites and substituted products thereof) as long as the object of the present invention is not impaired. UV absorbers (such as resorcinol, salicylate, benzotriazole and benzophenone), lubricants and release agents (such as montanic acid and its salts, esters, half esters thereof, stearyl alcohol, stearamide and polyethylene wax), dyes (such as nigrosine) And other additives such as colorants, plasticizers and antistatic agents, including pigments (eg, cadmium sulfide, phthalocyanine, and carbon black), and other thermoplastic resins to impart predetermined properties. Can be.

The composition of the present invention is preferably melt-kneaded. For example, using a Banbury mixer, a rubber roll machine, a kneader, a single-screw or twin-screw extruder, etc.
The composition can be melt-kneaded at a temperature of 400 ° C. to obtain a composition.

[0044]

The present invention will be described below in detail with reference to examples.

Reference Example 1 466 parts by weight of p-hydroxybenzoic acid, 84 parts by weight of 4,4'-dihydroxybiphenyl, 480 parts by weight of acetic anhydride, 75 parts by weight of terephthalic acid and an intrinsic viscosity of about 0.6
130 parts by weight of dl / g polyethylene terephthalate were charged into a reaction vessel equipped with a stirring blade and a distillation tube, and subjected to deacetic acid polycondensation under the following conditions.

First, at 100 to 250 ° C. in a nitrogen gas atmosphere.
After 5 hours at 250 to 300 ° C for 1.5 hours, the pressure was reduced to 0.5 mmHg at 300 ° C for 1 hour, and the reaction was further continued for 2.25 hours to complete the polycondensation.
Almost the theoretical amount of acetic acid was distilled off, and a liquid crystalline polyester having the following theoretical structural formula was obtained.

[0047]

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K / l / m / n = 75/10/15/25 Further, this polymer was placed on a sample stage of a polarizing microscope, and the temperature was raised to confirm the optical anisotropy. Showed good optical anisotropy, and the melting point (DSC) was 294 ° C. The logarithmic viscosity of this polymer (measured at 60 ° C. in pentafluorophenol at a concentration of 0.1 g / dl) is 1.
96 dl / g, 304 ° C., shear rate 1,000 /
The melt viscosity in seconds was 780 poise.

Reference Example 2 In a reaction vessel equipped with a stirrer and a distilling tube, 994 parts by weight of p-hydroxybenzoic acid, 223 parts by weight of 4,4'-dihydroxybiphenyl and 147 parts of 2,6-diacetoxynaphthalene were added.
Parts by weight, 299 parts by weight of terephthalic acid and acetic anhydride 1,
077 parts by weight were charged, and deacetic acid polycondensation was carried out under the following conditions.

First, at 100 to 250 ° C. in a nitrogen gas atmosphere.
After 5 hours at 250 to 330 ° C. for 1.5 hours, the pressure was reduced to 0.5 mmHg at 330 ° C. for 1.5 hours.
When the reaction was further reacted for 1.0 hour to complete the polycondensation, almost the theoretical amount of acetic acid was distilled off, and a liquid crystal polyester having the following theoretical structural formula was obtained.

[0051]

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K / l / m / n = 80 / 13.3 / 6.7 / 20 Further, as a result of placing this polymer on a sample stage of a polarizing microscope and raising the temperature to confirm the optical anisotropy, Good optical anisotropy was exhibited at 303 ° C. or higher, and the melting point (DSC) was 325 ° C.

The logarithmic viscosity of this polymer (measured in pentafluorophenol at a concentration of 0.1 g / dl at 60 ° C.) is 4.86 dl / g, 335 ° C., shear rate of 1,000
The melt viscosity at 0 / sec was 430 poise.

Examples 1 to 3 and Comparative Examples 1 to 6 The following epoxy compounds (B) ((a) to (a)) were added to 100 parts by weight of the thermotropic liquid crystal polyesters (A) obtained in Reference Examples 1 and 2, respectively. (D)) and the filler (C) shown in Table 1 were dry-blended at the respective compounding amounts, and
Using a 30 mmφ twin screw extruder set at 330 ° C., the mixture was melt-kneaded and then pelletized.

[0055]

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The pellets were supplied to Sumitomo Nestal injection molding machine Promat 40/25 (manufactured by Sumitomo Heavy Industries, Ltd.).
A 70 × 70 × 2 mm square plate was formed under the conditions of a cylinder temperature of 300 to 330 ° C. and a mold temperature of 90 ° C. Flow direction (MD) of resin from this square plate and its perpendicular direction (TD)
Each was cut into 1/2 "widths, and the flexural modulus was measured in accordance with ASTM D790, and the ratio of the MD / TD flexural modulus was determined as the mechanical anisotropy ratio.

Table 1 shows the results.

[0058]

[Table 1]

As is clear from the results shown in Table 1, the compositions of the present invention (Examples 1 and 2) obtained by adding glass fiber and an epoxy compound (a) having a specific structure to thermotropic liquid crystal polyester were mechanically different. Great improvement in anisotropy.

On the other hand, when the epoxy compound was not added (Comparative Examples 1 and 5) or when an epoxy compound other than the present invention was added (Comparative Examples 2 to 4 and 6), the mechanical anisotropy was improved. The effect is small.

Examples 4 to 5 and Comparative Examples 7 to 10 Examples 1 to 3 and Comparative Examples 1 to 6 show 100 parts by weight of the thermotropic liquid crystal polyester (A) obtained in Reference Examples 1 and 2, respectively. Epoxy compound (B) ((a),
(D)) After dry-blending 0 or 2.0 parts by weight, extrusion molding was performed in the same manner to determine the MD / TD flexural modulus.

Table 2 shows the results.

[0063]

[Table 2]

When the epoxy compound (a) was used (Comparative Examples 7 and 9) and the epoxy compound other than the present invention (Comparative Examples 8 and 10), The effect of improving mechanical anisotropy is small.

[0065]

The liquid crystal polyester composition of the present invention has a small mechanical anisotropy represented by dimensional accuracy and can be used for various uses as an engineering plastic.

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int. Cl. ⁷ , DB name) C08L 67/00 CA (STN) REGISTRY (STN)

Claims (2)

(57) [Claims] (A) 0.01 to 20 parts by weight of an epoxy compound represented by the following structural formula (1) and (C) 0 to 200 parts by weight of a filler with respect to 100 parts by weight of a thermotropic liquid crystal polyester. A liquid crystal polyester composition containing a part. Embedded image 2. The content of the filler (C) is 10-15.
2. The liquid crystal according to claim 1, wherein the amount is 0 parts by weight.
Polyester composition.