JPH09169894A - Liquid-crystal polyester resin composition - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a liquid-crystal polyester resin composition excellent in heat resistance, moldability and flowability and having high mechanical properties, high weld strength of a molding in particular, by blending a specified liquid-crystal polyester resin with a filler of a specified shape. SOLUTION: This composition consists of 99-20wt.% liquid-crystal polyester consisting of structural units of formula I [wherein X stands for at least one group selected from those of formula II; the carbonyl groups of structural units (IV) are at the p- or m-positions to each other, at least 50% of which are at the p-positions; and the total of the structural units (II) and (III) are substantially equimolar to the structural units (IV)], having a heat distortion temperature of 190-280 deg.C and a liquid-crystal initiation temperature of 330 deg.C or lower and forming an anisotropic melt phase with a melt viscosity of 10,000P or lower, and 1-80wt.% flaky or particulate filler. This composition is useful for a molded article having a weld part.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to heat resistance, moldability,
The present invention relates to a liquid crystal polyester resin composition having excellent fluidity and mechanical properties, particularly high weld strength of a molded product.

[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 new properties have been developed and marketed. Among them, the polymer is characterized by a parallel arrangement of molecular chains. Optically anisotropic liquid crystal polymers have attracted attention because of their excellent mechanical properties.

As a polymer forming an anisotropic molten phase, for example, a liquid crystal polymer obtained by copolymerizing polyethylene terephthalate with p-hydroxybenzoic acid (JP-A-49-7239)
No. 3), a liquid crystal polymer obtained by copolymerizing p-hydroxybenzoic acid and 6-hydroxy-2-naphthoic acid (Japanese Patent Laid-Open No.
And a liquid crystal polymer obtained by copolymerizing p-hydroxybenzoic acid with 4,4'-dihydroxybiphenyl, terephthalic acid and isophthalic acid (Japanese Patent Publication No. 57-24).
No. 407) is known.

It is also known to incorporate glass fibers for the purpose of improving the weld strength of a liquid crystal polymer molded product.

[0005]

However, the liquid crystal polymers known so far have a low heat distortion temperature of less than 190 ° C. and have insufficient heat resistance, or have a heat distortion temperature of 190 ° C. Although the above heat resistance is good, a liquid crystal polymer having a balance of heat resistance, moldability and fluidity, such as high melt viscosity, cannot be molded unless the liquid crystal starting temperature is too high and the temperature is 400 ° C. or higher. It was difficult.

Liquid crystal polymers have low weld strength in molded products. To solve this problem, if glass fibers are added,
There was a problem of a large decrease in liquidity.

Therefore, the present invention solves the above problems,
An object of the present invention is to obtain a liquid crystal polyester resin composition having excellent heat resistance, moldability, fluidity, and mechanical properties, particularly high weld strength of a molded product.

[0008]

That is, the present invention provides an anisotropic molten phase comprising the following structural units having a heat distortion temperature of 190 to 280 ° C., a liquid crystal onset temperature of 330 ° C. or less, and a melt viscosity of 10,000 poise or less. Liquid crystal polyester to be formed (A)
99 to 20% by weight and a plate-like or granular filler (B) 1 to
A liquid crystal polyester resin composition comprising 80% by weight and

Embedded image (However, X in the formula is

Embedded image The carbonyl group of the structural unit (IV) is in a para or meta position relative to each other,
50 mol% or more is in the para position. The structural unit (I
The sum of I) and (III) is substantially equimolar to structural unit (IV). (2) A molded article having a welded part made of the liquid crystal polyester resin composition according to claim (1).

[0009]

BEST MODE FOR CARRYING OUT THE INVENTION The structural unit (I) of the thermoplastic polyester (A) in the present invention is a structural unit formed from p-hydroxybenzoic acid, and the structural unit (II) is 4,4'-dihydroxy. A structural unit formed from biphenyl, wherein the structural unit (III) is hydroquinone, t-butylhydroquinone, phenylhydroquinone, 2,6
-A structural unit formed from one or more dihydroxy compounds selected from dihydroxynaphthalene,
(IV) each represents a structural unit formed from terephthalic acid and / or isophthalic acid.

The liquid crystal polyester (A) of the present invention is a copolymer composed of the structural units (I), (II), (III) and (IV).

The copolymerization amount of the structural units (I) to (IV) is arbitrary. The following copolymerization amount is preferable from the viewpoint of fluidity. That is, the structural unit (I) is 40 to 9 with respect to the total of the structural units (I), (II) and (III).
It is preferably 0 mol%, particularly 60 to 78 mol%.
It is preferred that The molar ratio of the structural units (II) and (III) [(II) / (III)] is 9/1 to 1 /
9 is preferable, 7.5 / 2.5 to 2.5 / 7.5 are preferable, and 7.5 / 2.5 to 4/6 are particularly preferable. Also,
Total of structural units (II) and (III) and structural unit (IV)
Are substantially equimolar. Further, the structural unit (IV) is a structural unit generated from terephthalic acid and / or a structural unit generated from isophthalic acid, and 50 mol% or more thereof is a structural unit generated from terephthalic acid.

Liquid crystalline polyester (A) used in the present invention
Has a heat distortion temperature of 190 to 2 when the filler is not mixed.
It is essential that the temperature is 80 ° C.

If the heat distortion temperature is less than 190 ° C., the heat resistance is insufficient, and if it exceeds 280 ° C., the molding temperature of the obtained resin composition becomes high.

Here, the heat distortion temperature is a value measured on a test piece having a thickness of 1/8 "at a stress of 18.6 kg / cm ² based on ASTM D648.

The liquid crystal starting temperature of the liquid crystal polyester (A) is essential to be 330 ° C. or lower, and is preferably 260 to 330 ° C. from the viewpoint of fluidity and heat resistance.

When the liquid crystal starting temperature exceeds 330 ° C., it is necessary to raise the molding temperature, which is not practical from the viewpoint of moldability.

It is essential that the melt viscosity is 10,000 poises or less, preferably 5,000 poises or less, and more preferably 2,000 poises or less.

The melt viscosity is (liquid crystal starting temperature +4
0 ° C.) and a shear rate of 1,000 (1 / second) under the conditions of a Koka flow tester.

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

For example, the following production methods (1) to (4) are preferred.

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

(2) p-hydroxybenzoic acid, 4,4 '
A method of reacting an aromatic dihydroxy compound such as dihydroxybiphenyl or hydroquinone, or an aromatic dicarboxylic acid such as terephthalic acid with acetic anhydride to acylate a phenolic hydroxyl group, followed by a deacetic acid polycondensation reaction.

(3) Produced by dephenol polycondensation reaction from an aromatic dihydroxy compound such as phenyl ester of p-hydroxybenzoic acid, 4,4'-dihydroxybiphenyl and hydroquinone and a diphenyl ester of aromatic dicarboxylic acid such as terephthalic acid. how to.

(4) Aromatic dicarboxylic acids such as p-hydroxybenzoic acid and terephthalic acid are reacted with desired amounts of diphenyl carbonate to form diphenyl esters, and then aromatic compounds such as 4,4'-dihydroxybiphenyl and hydroquinone. Add the dihydroxy compound,
A method of producing by a dephenol polycondensation reaction.

Since the liquid crystal polyester (A) having a high degree of polymerization can be obtained, it is more preferable to use the method (2).
Typical catalysts used in the polycondensation reaction include metal compounds such as stannous acetate, tetrabutyl titanate, potassium acetate, antimony trioxide, magnesium, sodium acetate, and zinc acetate. It is effective for

Some of the liquid crystal polyesters (A) of the present invention are capable of measuring the intrinsic viscosity in pentafluorophenol, and in that case, the concentration is 60 at a concentration of 0.1 g / dl.
It is preferably 0.5 dl / g or more, more preferably 1.0 to 15.0 dl / g, as measured at ° C.

When polycondensing the liquid crystalline polyester (A) used in the present invention, in addition to the components constituting the above (I) to (IV), 4,4'-diphenyldicarboxylic acid,
3,3'-diphenyldicarboxylic acid, 3,4'-diphenyldicarboxylic acid, 2,2'-diphenyldicarboxylic acid, 1,2-bis (phenoxy) ethane-4,4'-dicarboxylic acid, 1,2-bis Aromatic dicarboxylic acids such as (2-chlorophenoxy) ethane-4,4'-dicarboxylic acid, alicyclic dicarboxylic acids such as hexahydroterephthalic acid, resorcin, chlorohydroquinone, methylhydroquinone, 2,7-dihydroxynaphthalene, etc. Aromatic dihydroxy compound, m-oxybenzoic acid, 2,6-
Aromatic oxycarboxylic acids such as oxynaphthoic acid and p-aminophenol, p-aminobenzoic acid and the like can be further copolymerized in a small proportion within a range not impairing the object of the present invention.

The plate-like or granular filler (B) in the present invention is not particularly limited, and known ones can be used. For example, calcium silicate (Warastenite), calcium phosphate, calcium sulfate, calcium carbonate, magnesium carbonate, barium sulfate, titanium oxide,
Aluminum oxide, magnesium oxide, zinc oxide, silicon oxide, iron oxide, zirconium oxide, antimony trioxide, molybdenum dioxide, molybdenum disulfide, mica, sericite, talc, kaolin, clay, feldspar, vermiculite, silica, glass powder, Carbon black, graphite,
Resin powder and ebonite powder can be preferably used.

The surface of the filler (B) is a coupling agent such as γ- (2-aminoethyl) aminopropyltrimethoxysilane, γ-glycidoxypropyltrimethoxysilane, γ-mercaptopropyltrimethoxysilane. Silane coupling agents such as silane, methyltrimethoxysilane, γ-anilinopropyltrimethoxysilane, hydroxypropyltrimethoxysilane, γ-ureidopropyltriethoxysilane and vinylacetoxysilane, isopropyl tris isostearoyl titanate, isopropyl tris (Dioctyl pyrophosphate) titanate, isopropyl tri (N-aminoethyl-aminoethyl) titanate, tetraoctyl bis (ditridecyl phosphite) titanate, bis (dioctyl pyrophosphate) G) Titanate coupling agents such as ethylene titanate, isopropyl tridecylbenzene sulfonyl titanate, isopropyl tri (dioctyl phosphate) titanate, aluminum coupling agents such as acetoalkoxyaluminum diisopropylate and zircoaluminate coupling agents, etc. It is preferable that the liquid crystal polyester resin composition is used after being subjected to a coupling treatment because the heat resistance and mechanical properties of the liquid crystal polyester resin composition are improved.

In the present invention, liquid crystal polyester (A)
The compounding amount of 99 to 20% by weight, preferably 95 to 30% by weight, particularly preferably 90 to 40% by weight, and the compounding amount of the plate-like or granular filler (B) is 1 to 80% by weight, preferably 5 to 70% by weight, particularly preferably 10 to 60% by weight
It is. If the content of the filler (B) is less than 1% by weight, the weld strength of the molded product will be insufficient, and if it exceeds 80% by weight, the fluidity will be significantly reduced, which is not practical.

The composition of the present invention contains an antioxidant and a heat stabilizer (for example, hindered phenol, hydroquinone, phosphites and their substitution products), ultraviolet rays, and the like, to the extent that the objects of the present invention are not impaired. Absorbents (eg resorcinol, salicylate, benzotriazole, benzophenone etc.), lubricants and mold release agents (montanic acid and its salts, its esters, its half esters, stearyl alcohol, stearamide and polyethylene wax etc.), dyes (eg nitrocin etc.) And a colorant containing a pigment (for example, cadmium sulfide, phthalocyanine, carbon black, etc.), a flame retardant,
Ordinary additives such as a plasticizer, an antistatic agent, and a toughening agent and other thermoplastic resins can be added to impart predetermined characteristics.

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

The composition thus obtained can be molded by a method such as injection molding, and is excellent in weld strength, so that it is useful for a molded article having a weld portion.

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

Reference Example 1 519 parts by weight of p-acetoxybenzoic acid, 184 parts by weight of 4,4'-diacetoxybiphenyl, 85 parts by weight of t-butyl hydroquinone diacetate, 19.4 parts by weight of hydroquinone diacetate and 186 parts by weight of terephthalic acid. Part was charged into a reaction vessel equipped with a stirring blade and a distillation tube, reacted at 250 to 340 ° C. for 3.0 hours under a nitrogen gas atmosphere, heated to 350 ° C., and then depressurized to 1.5 mmHg. After further heating for 1.0 hour, polycondensation reaction was performed to obtain a resin (a) having the following theoretical structural formula.

[0036]

Embedded image 1 / m / n / o / p = 72/17 / 8.5 / 2.5 / 2
8 Place this polyester on the sample stage of a polarizing microscope.
When the temperature was raised and the optical anisotropy was confirmed, the liquid crystal onset temperature was 307 ° C., indicating good optical anisotropy. The logarithmic viscosity of this polyester (measured at 60 ° C. in pentafluorophenol at a concentration of 0.1 g / dl) is 4.3 dl /
and the melt viscosity at a shear rate of 1,000 / sec at 347 ° C. was 4,300 poises.

Reference Example 2 541 parts by weight of p-acetoxybenzoic acid, 184 parts by weight of 4,4'-diacetoxybiphenyl, 62 parts by weight of hydroquinone diacetate and 124 parts by weight of terephthalic acid,
42 parts by weight of isophthalic acid was charged into a reaction vessel equipped with a stirring blade and a distillation tube, reacted at 250 to 360 ° C. for 3 hours under a nitrogen gas atmosphere, depressurized to 1 mmHg, further heated for 1 hour, and subjected to polycondensation. Was completed to obtain a resin (b) having the following theoretical structural formula.

[0038]

[Chemical 6] 1 / m / n / o / p = 75/17/8 / 18.75 /
6.25 This polyester was placed on a sample stage of a polarizing microscope, and the temperature was raised to confirm the optical anisotropy.
The temperature was 05 ° C., indicating good optical anisotropy. The logarithmic viscosity of this polyester (measured under the same conditions as in Reference Example 1) was 4.1 dl / g, 345 ° C., shear rate 1,000 /
The melt viscosity in seconds was 3,500 poise.

Examples 1 to 6 Liquid crystalline polyester (A) and plate-like or granular filler (B) were melt-mixed by a 30 mmφ twin-screw extruder set at 300 to 360 ° C. at the ratio shown in the table, It was a resin composition. The filler (B) is 0.1 to 0.5 in advance.
It was treated with γ-glycidoxypropyltrimethoxysilane (part by weight: 100 parts by weight of filler) and used as the filler (B).

The resin composition thus obtained was applied to Sumitomo Nestal injection molding machine Promat 40/25 (Sumitomo Heavy Industries, Ltd.).
) At a cylinder temperature of 300 to 360 ° C and a mold temperature of 100 to 150 ° C.
A 5 ″ test piece and an ASTM NO. 1 dumbbell were molded. The ASTM NO. 1 dumbbell consists of a normal mold with the gate at one end of the dumbbell (Dumbbell I) and a weld mold with the gate at each end of the dumbbell (dumbbell). II) was used for molding, and the flexural modulus of a 1/8 "-thick test piece was measured according to the ASTM D648 standard. In addition, according to ASTM D638 standard, ASTM N
The breaking strength of No. 1 dumbbell was measured, and the ratio of the breaking strength of dumbbell II to dumbbell I was defined as the weld strength retention rate. In addition, the cylinder temperature during molding of the resin composition and the melt viscosity at a shear rate of 1,000 / sec were measured with a Koka type flow tester. The results are shown in the table.

Comparative Examples 1-2 Using the liquid crystalline polyester (A) of Reference Examples 1-2, 1/8 "× under the conditions of a cylinder temperature of 300-350 ° C. and a mold temperature of 100 ° C. as in Examples 1-6. A 1/2 ″ × 5 ″ test piece and ASTM No. 1 dumbbell were molded.
Then, the heat distortion temperature, the flexural modulus, the breaking strength, and the melt viscosity were measured, and the weld strength retention rate was calculated. The results are shown in the table.

Comparative Example 3 It has the following theoretical structural formula and has a liquid crystal starting temperature of 359 ° C.
Melt viscosity at 9 ° C and shear rate of 1,000 / sec is 880
Using liquid crystal polyester (X) of 0 poise,
The filler (B) was melt-mixed (set temperature 400 ° C.), molded (cylinder temperature 400 ° C., mold temperature 210 ° C.) and evaluated in the proportions shown in the table in the same manner as in 6. The results are shown in the table.

[0043]

Embedded image 1 / m / n = 67/33/33 In comparison with Comparative Examples 1 and 2, the resin compositions of Examples 1 to 6 of the present invention have high heat distortion temperature and bending elastic modulus, and have excellent heat resistance and mechanical properties. Are better. Further, the melt viscosity at the molding temperature is 6,000 poise or less, and the fluidity is excellent. Further, the weld strength retention rate is remarkably high.

The resin composition of Comparative Example 3 has a high heat distortion temperature and a high flexural modulus, but has a high melt viscosity at the molding temperature of 400 ° C. of 19,000 poise and a low fluidity. Evolution of pyrolysis gas was observed when the molding temperature exceeded 400 ° C. Also, the weld strength retention rate was as low as 37%.

[0045]

[Table 1]

[0046]

INDUSTRIAL APPLICABILITY According to the present invention, by adding a plate-like or granular filler to a specific liquid crystal polyester having a limited structural formula, heat resistance, moldability and fluidity are excellent, mechanical properties, In particular, a resin composition having high weld strength can be obtained.

Claims (2)

[Claims] 1. A heat distortion temperature comprising the following structural unit: 190
Liquid crystal polyester (A) 99 to 20% by weight and a plate-like or granular filler (B) which forms an anisotropic molten phase having a liquid crystal starting temperature of 330 ° C. or less and a melt viscosity of 10,000 poise or less. A liquid crystal polyester resin composition comprising 1 to 80% by weight. Embedded image (Where X in the formula is The carbonyl group of the structural unit (IV) is in a para or meta position relative to each other,
50 mol% or more is in the para position. The structural unit (I
The sum of I) and (III) is substantially equimolar to structural unit (IV). ) 2. A molded article having a welded portion, which is made of the liquid crystal polyester resin composition according to claim 1.