JPH032259A - liquid crystal polyester composition - Google Patents

Abstract

PURPOSE:To provide a liquid crystal polyester composition having excellent heat resistance represented by good hydrolysis resistance and long period aging resistance by adding a specific amount of a carbodiimide compound to a liquid crystal polyester comprising specified structural units. CONSTITUTION:A liquid crystal composition comprises (A) 100 pts.wt. of an anisotropic melt phase-forming liquid crystal polyester having a thermal deformation temperature of >=150 deg.C and comprising structural units of formulas I, II and III [R1 is a group of formula IV, V, VI, etc., preferably the group of formula IV; R2 and R3 are groups of formulas IV, V, VII (X is H or Cl), etc., preferably the group of formula V], the sum of the groups of formulas I and II being 75-95mol%, the amount of the group of formula III being 25-5mol% based on the total amount of the composition and the molar ratio of the group of formula I to the group of formula II being 75/25-95/5, (B) 0.01-20 pts.wt., preferably 0.05-10 pts.wt., of a carbodiimide compound (preferably dicyclohexylcarbodiimide) and preferably further (C) 0-200 pts.wt. of a filler.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application] The present invention relates to a liquid crystalline polyester composition having excellent heat resistance, typified by extremely high hydrolysis resistance and long-term aging properties.

[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 chemical resistance and mechanical properties. (
JP-A-518395, JP-A-49-72393).

As the above-mentioned liquid crystal polymer, for example, a liquid crystal polyester obtained by copolymerizing p-hydroxybenzoic acid with polyethylene terephthalate is known (Japanese Patent Laid-Open No. 49-723
Publication No. 93).

[Problem to be solved by the invention]

However, since the above-mentioned liquid crystal polyester has a low glass transition temperature, its stability against water, that is, its hydrolysis resistance or long-term aging properties are not necessarily sufficient, which poses a problem in its practical use.

Therefore, the object of the present invention is to solve the above-mentioned problems and to obtain a liquid crystal polyester composition having excellent heat resistance, typified by hydrolysis resistance and long-term aging properties.

As a result of intensive studies to achieve the above-mentioned problems, the present inventors found that liquid crystal polyester consisting of a specific structural unit,
The inventors have discovered that a composition containing a specific amount of a carbodiimide compound satisfies the above-mentioned problems, and have arrived at the present invention.

[Means to solve the problem]

That is, the present invention provides (A) the following structural units (I) to (II)
I), the structural unit [(I)+(I[)) is 75 to 95 mol% of the total, and the structural unit (III) is 25 to 95 mol% of the total.
An anisotropic melt phase-forming liquid crystal polyester that accounts for 5 mol%, has a molar ratio of structural units (I)/(IF) in the range of 75/25 to 9515, and has a heat distortion temperature of 150°C or higher. For 100 parts by weight, (B) 0.01 to 20 parts by weight of carbodiimide compound and (C) 0 to 2 parts by weight of filler
00 parts by weight of the liquid crystalline polyester composition.

Record C.I.

+ O-R+-0-zC-Rz-CO+・・・・・・
・ (II) + 0-CHzCHz-0□C-R, -CO+...
Represents one or more groups selected from ..., ..., (■), and R
2 and R1 may be the same. In the formula, X represents a hydrogen atom or a chlorine atom.) The liquid crystal polyester (A) used in the present invention is composed of the above structural units, has a heat distortion temperature of 150°C or higher, and has a property of forming an anisotropic melt phase. It has the following.

In this liquid crystal polyester (A), the above structural unit (
I) is a structural unit of polyester produced from p-hydroxybenzoic acid, and the above structural unit (II) is 4.4-
Dihydroxybiphenyl, hydroquinone, 4,4-dihydroxydiphenyl ether, 2,6-hydroxynaphthalene, -butylhydroquinone, 3.3',
An aromatic diol selected from 5.5-tetramethyl-4,4-dihydroxybiphenyl, phenylhydroquinone and bisphenol A, and terephthalic acid, 4.4-
selected from diphenyldicarboxylic acid, 2,6-naphthalene dicarboxylic acid, 1,2-bis(phenoxy)ethane-4,4-dicarboxylic acid and 1,2-bis(2-chlorophenoxy)ethane-4,4-dicarboxylic acid This figure shows the structural unit of polyester produced from aromatic carboxylic acid.

In addition, the above structural unit (III) is terephthalic acid, 4.4
-diphenyldicarboxylic acid, 2,6-naphthalene dicarboxylic acid, 1,2-bis(phenoxy)ethane-4,4-
It is a structural unit of polyester produced from ethylene glycol and an aromatic dicarboxylic acid selected from dicarboxylic acid and 1,2-bis(2-chlorophenoxy)ethane-4,4-dicarboxylic acid.

Among these, -Q G is most preferable for R, and 0 is most preferable for R2 and R1.

On the other hand, the above-mentioned structural units (I) to (structural units (N)+(II) in I[[)) account for 75 to 95 mol%, preferably 77 to 90 mol% of the total.

Further, the above structural unit (In) is 25 to 5 mol% of the total,
Preferably it accounts for 23 to 10 mol%. If the ratio of structural units ((I) + (II)) is larger than 95 mol% of the total, melt fluidity will decrease and solidification occurs during polymerization, and if it is smaller than 75 mol%, heat resistance will be poor, so it is preferable. do not have.

In addition, the molar ratio of the structural units (I)/(II) is 75/
The range of 25 to 9515, preferably 7B/22 to 92/8 is suitable. If the molar ratio is less than 75/25 or greater than 9515, heat resistance and/or fluidity will be poor, making it difficult to achieve the object of the present invention.

A typical method for producing the liquid crystal polyester (A) used in the present invention includes the following method.

(I) Acylated products of hydroxybenzoic acid 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 glycols such as polyethylene terephthalate. A method of deacetic acid polymerization of polyester from aromatic dicarboxylic acid.

(2) p-hydroxybenzoic acid, aromatic dihydroxy compounds such as 4,4-dihydroxybiphenyl, acetic anhydride,
A method of deacetic acid polymerization of aromatic dicarboxylic acids such as terephthalic acid, ethylene glycol such as polyethylene terephthalate, and polyesters from aromatic dicarboxylic acids.

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

Further, the melt viscosity of the liquid crystal polyester (A) used in the present invention is preferably in the range of 10 to 15,000 poise, particularly 20 to 5,000 poise.

Note that this melt viscosity is a value measured using a Koka type flow tester under the conditions of (liquid crystal starting temperature +40°C) and a shear rate of 1.000 (I/sec).

On the other hand, the logarithmic viscosity of this liquid crystal polyester is 0.1 g/a
The concentration, measured in pentafluorophenol at 60°C, is 0.5 to 5 a/g, especially 1.0 to 3. Oa/
A range of g is preferred.

In addition, when polycondensing the liquid crystal polyester (A) used in the present invention, in addition to the components constituting the structural units (I) to (DI), isophthalic acid, 3,3-diphenyldicarboxylic acid, 2,2-diphenyl Aromatic dicarboxylic acids such as dicarboxylic acids, aliphatic dicarboxylic acids such as adipic acid, azelaic acid, sebacic acid, dodecanedioic acid, alicyclic dicarboxylic acids such as hexahydroterephthalic acid, chlorohydroquinone, methylhydroquinone, 4.4- Aromatic diols such as dihydroxydiphenylsulfone, 4,4-dihydroxydiphenylpropane, 4,4'-dihydroxydiphenylsulfide, 4,4'-dihydroxybenzophenone, 1,4-butanediol, 1,6-hexanediol, neopentyl glycol , 1,4-cyclohexanediol, 1,4-cyclohexane dimetatool, and other aliphatic and alicyclic diols; and m-hydroxybenzoic acid, 2,6-hydroxynaphthoic acid, and other aromatic hydroxycarboxylic acids. Further copolymerization can be carried out within a small proportion that does not impair the purpose of copolymerization.

Next, the carbodiimide compound (B) used in the present invention is a compound having a carbodiimide group (-N=C=N-) in the molecule, and specifically, diisopropylcarbodiimide, dicyclohexylcarbodiimide, di-o -Tolylcarbodiimide, diphenylcarbodiimide, dioctyldecylcarbodiimide, di-2,6-dimethylphenylcarbodiimide, N-triyl-N'-phenylcarbodiimide, di-p-nitrophenylcarbodiimide, di-p-aminophenylcarbodiimide, -p
-Hydroxyphenylcardiimide, di-p-tolylcarbodiimide, di-p-chlorophenylcarbodiimide, di-p-methoxyphenylcarbodiimide, di-3
゜4-dichlorophenylcarbodiimide, di2゜5-
Dichlorophenylcarbodiimide, di-rolphenylcarbodiimide, p-phenylene-bis-di0-
Triylcarbodiimide, P-phenylene-bis-dicyclohexylcarbodiimide, p-phenylene-bis-p-chlorophenylcarbodiimide, hexamethylene-bis-dicyclohexylcarbodiimide, ethylene-bis-dicyclohexylcarbodiimide, ethylene-
Mono- or dicarbodiimide compounds such as bis-diphenylcarbodiimide and poly(4,4'-diphenylmethanecarbodiimide), poly(3,3'-dimethyl-4,4-biphenylmethanecarbodiimide), poly
(tolylcarbodiimide), poly(p-phenylenecarbodiimide), poly(m-phenylenecarbodiimide), poly(3,3'-dimethyl-4,4-diphenylmethanecarbodiimide), poly(naphthylenecarbodiimide), poly(I16-hexa methylenecarbodiimide), poly(4,4-methylenebiscyclohexylcarbodiimide), poly(I,3 and 1,4-cyclohexylenecarbodiimide), poly(I,3-diisopropylphenylenecarbodiimide), poly(I-methyl- Examples include polycarbodiimide compounds such as 3,5-diisopropylphenylenecarbodiimide), poly(I,3,5-triethylphenylenecarbodiimide), and poly(triisopropylphenylenecarbodiimide), and two or more of these can also be used in combination. .

Among these, dicyclohexylcarbodiimide,
Di2,6-dimethylphenylcarbodiimide, Di0
Preference is given to using -tolylcarbodiimide, BoIJ (4,4'-diphenylmethanecarbodiimide), poly(tolylcarbodiimide), poly(p-phenylenecarbodiimide) and poly(triisopropylphenylenecarbodiimide).

The amount of these carbodiimide compounds (B) added is 0.01 to 20 parts by weight, preferably 0.05 to 10 parts by weight, more preferably 0.1 to 5 parts by weight, based on 100 parts by weight of the liquid crystal polyester (A). be. If the amount added is more than 20 parts by weight, the composition will not only be colored but also have an adverse effect on the mechanical properties, and if it is less than 0.01 parts by weight, the effect of improving hydrolysis resistance will not be obtained, which is not preferable.

In the present invention, by blending the carbodiimide compound (B) with the liquid crystal polyester (A), the effect of improving hydrolysis resistance and long-term aging characteristics can be obtained. Furthermore, if a filler (C) is used in combination, it is possible to obtain the effect of synergistically further improving the hydrolysis resistance and long-term aging property as well as the reinforcing effect of the filler.

Therefore, the filler (C) used in the present invention includes glass fiber, glass fiber, alumina fiber, silicon carbide fiber, ceramic fiber, asbestos fiber, gypsum fiber,
Inorganic fibers such as metal fibers (e.g. stainless steel fibers) and fibrous fillers such as carbon fibers and silicates such as wollastenite, sericite, kaolin, mica, clay bentonite, asbestos, talc, alumina silicate, alumina, silicon oxide , metal oxides such as magnesium oxide, zirconium oxide, titanium oxide, carbonates such as calcium carbonate, magnesium carbonate, dolomite, sulfates such as calcium sulfate, barium sulfate, powders such as glass peas, boron nitride, silicon carbide and Saroyan. or particulate fillers, which may be hollow (for example, hollow glass fibers, glass microballoons, glass balloons, carbon balloons, etc.). Further, the above-mentioned reinforcing material may be used after being pretreated with a coupling agent such as a silane type or a titanium type, if necessary.

The amount of these fillers (C) added is based on the liquid crystal polyester (A).
The range is 0 to 200 parts by weight per 100 parts by weight,
If the amount exceeds 200 parts by weight, the mechanical properties and moldability will deteriorate significantly, which is not preferable.

The liquid crystal polyester composition of the present invention contains antioxidants and heat stabilizers (
UV absorbers (such as resorcinol, salicylates, benzotriazoles and benzophenones), lubricants and mold release agents (montanic acid and its salts, its esters, its colorants, flame retardants, including half esters, stearic alcohol, stearamide and polyethylene wax), dyes (such as nitrosine) and pigments (such as cadmium sulphide, phthalocyanine and carbon black);
Conventional additives such as plasticizers and antistatic agents and other thermoplastics can be added to impart desired properties.

The method for preparing the liquid crystalline polyester composition of the present invention is preferably a melt-kneading method, and known methods can be used for melt-kneading.

For example, Banbury mixer, rubber roll machine, kneader
1 Using a single-screw or twin-screw extruder, 200 to 400
The composition can be prepared by melt-kneading at a temperature of .degree.

〔Example〕

The present invention will be further explained below 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 0.6a
/g of polyethylene terephthalate was charged into a reaction vessel equipped with a stirring blade and a distillation tube, and acetic acid depolymerization was carried out under the following conditions.

First, after reacting at 100 to 250°C for 5 hours and at 250 to 300°C for 1.5 hours in a nitrogen gas atmosphere,
The pressure was reduced to 0.3 Hg at 00°C for 11 hours, and further 3.
When the reaction was carried out for 75 hours and the polycondensation was completed, almost a theoretical amount of acetic acid was distilled out, and a liquid crystal polyester (A-1) having the following theoretical structural formula was obtained.

1/m/n = 75/10/15 Also,
This polyester (A-1) 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 initiation temperature was 272°C, indicating good optical anisotropy. Ta. Logarithmic viscosity of this polyester (A-1) (0.1 g #
(measured at 60 °C in pentafluorophenol at a concentration of 312 °C 1
The melt viscosity at ,000/sec was 2900 poise. Further, the heat distortion temperature was 208°C (the measurement method will be described later).

Reference Example 2 72.58 parts by weight of p-acetoxybenzoic acid and polyethylene terephthalate 5 having an intrinsic viscosity of about 0.6 a/g
1.61 parts by weight was charged into a reaction vessel equipped with a stirring blade and a distillation tube, and reacted at 200 to 250°C for 5 hours and at 250 to 280°C for 2 hours in a nitrogen gas atmosphere.
When the pressure was reduced to 0.6 mm/g over 1 hour at °C and the reaction was continued for 2 hours, almost a theoretical amount of acetic acid was distilled out, yielding a liquid crystal polyester (A-2) having the following theoretical structural formula.

1/m=60/40 Also, as a result of placing this polyester (A-2) on the sample stage of a polarizing microscope, raising the temperature, and observing the optical anisotropy,
The liquid crystal start temperature was 240°C, and good optical anisotropy was exhibited. The logarithmic viscosity (measured under the same conditions as Reference Example 1) of this polyester (A-2) was 0.71 di/g,
The melt viscosity at 280°C2 shear rate 1,000/sec was 810 voids.

In addition, the heat distortion temperature was 64°C (measurement method will be described later)
.

Examples 1-5. Comparative examples 1 to 6 Liquid crystal polyester (A-1) obtained in Reference Example 1.2.

(A-2) and 100 parts by weight of polybutylene terephthalate having an logarithmic viscosity of 1.2 (Toshisha product), various carbodiimide compounds shown in Table 1 were triblended in the respective blending amounts, and 250 parts by weight of each were triblended. The mixture was melt-kneaded and pelletized using a 30 mmφ twin-screw extruder set at ~300°C.

This pellet is inhabited by Nestal injection molding machine Promatsu) 4
0/25 (manufactured by Sumitomo Heavy Industries, Ltd.) under the conditions of a cylinder temperature of 250 to 300"C and a mold temperature of 40 to 90"C.
A test piece measuring 8" thick x 1/2' wide x 5" long was molded.

Next, the obtained ASTM Nα1 dumbbells were placed in a 32 pressure container containing ion-exchanged water, and a hydrolysis resistance test was conducted for 60 days in an open gear maintained at 80°C. ASTM Nα1 dumbbells were tested for tensile strength (k
g-f/cffl) was measured, and the hydrolysis resistance was evaluated from the retention rate.

On the other hand, eight STM Nα1 dumbbells were placed in a gear oven maintained at 190"C and subjected to a heat aging test for 60 days.
The tensile strength of the STM Nα1 dumbbell was measured in the same manner as above, and the long-term aging property (heat resistance) was evaluated from the retention rate.

In addition, the heat deformation temperature (I8.6 kg/cffl) of a 1/8" thick x 172" wide x 5'' long test piece was measured using a Toyo Seiki model deformation temperature measuring device. The results are also shown in Table 1.

(Margins below this page) As is clear from the results in Table 1, the composition of the present invention, which is made by adding a carbodiimide compound to a liquid crystal polyester with a specific structure, has excellent heat resistance as typified by hydrolysis resistance and long-term aging properties. is extremely excellent.

On the other hand, when no carbodiimide compound is added (Comparative Example 1) or when the amount of carbodiimide compound added is small (
In Comparative Example 2), there is a large decrease in mechanical properties during hot water treatment and long-term aging.

Furthermore, when a liquid crystal polyester other than the present invention is used (Comparative Example 3.4) or when polybutylene terephthalate is used (Comparative Examples 5 and 6), even when a carbodiimide compound is added, hydrolysis resistance and long-term aging The effect of improving characteristics is small.

Examples 6-10. Comparative Examples 7-12 Liquid crystalline polyester (A-1) obtained in Reference Examples 1 and 2.

(A-2) and 100 parts by weight of polybutylene terephthalate (manufactured by Toshisha Seikai) with a logarithmic viscosity of 1.2, glass fiber (3-length chopped strand type)
After tri-blending 40 parts by weight and the various carbodiimide compounds shown in Table 2 in the proportions shown in Table 2, 30 parts by weight
The mixture was melt-kneaded at 250 to 300'C using a mmφ twin-screw extruder and then pelletized.

Sumitomo Necool injection molding machine Promatsu 1-
40/25 (manufactured by Sumitomo Heavy Industries, Ltd.) under the conditions of cylinder temperature 250-300"C and mold temperature 40-90°C.
A test piece measuring 8" thick x 1/2' wide x 5" long was molded. Using the obtained test pieces, physical properties were evaluated under the same conditions as in Examples 1 to 5 and Comparative Examples 1 to 6.

These results are shown in Table 2.

(Margin below this page) As is clear from the results in Table 2, it is clear that the composition of the present invention when glass fiber is added has even better hydrolysis resistance and long-term aging properties.

〔Effect of the invention〕

The liquid crystal polyester composition of the present invention has excellent heat resistance, typified by hydrolysis resistance and long-term aging properties, and is used for mechanical parts, automobile parts, sealing materials, etc. that are exposed to high temperature, high humidity, or high temperature conditions. Useful for applications.

Agent: Patent Attorney Nobuo Kogawa -

Claims (1)

[Scope of Claims] (A) Consists of the following structural units (I) to (III), in which the structural units [(I) + (II)] account for 75 to 95 mol% of the total, and the structural unit (III) accounts for 75 to 95 mol% of the total. Formation of an anisotropic melt phase that accounts for 25 to 5 mol%, has a molar ratio of structural units (I)/(II) in the range of 75/25 to 95/5, and has a heat distortion temperature of 150°C or higher A liquid crystalline polyester composition comprising: (B) 0.01 to 20 parts by weight of a carbodiimide compound and (C) 0 to 200 parts by weight of a filler, based on 100 parts by weight of a liquid crystalline polyester. ▲There are mathematical formulas, chemical formulas, tables, etc.▼・・・・・・・・・(
I) ▲There are mathematical formulas, chemical formulas, tables, etc.▼・・・・・・・・・(
II) ▲There are mathematical formulas, chemical formulas, tables, etc.▼・・・・・・・・・(
III) (However, R_1 in the formula is ▲There are mathematical formulas, chemical formulas, tables, etc.▼, ▲There are mathematical formulas, chemical formulas, tables, etc.▼, ▲Mathematical formulas, chemical formulas,
There are tables, etc. ▼, ▲ There are mathematical formulas, chemical formulas, tables, etc. ▼
, ▲There are mathematical formulas, chemical formulas, tables, etc.▼,▲Mathematical formulas, chemical formulas,
R_2 and R_3 are one or more groups selected from ▼, ▲Mathematical formulas, chemical formulas, tables, etc.▼ and ▲Mathematical formulas, chemical formulas, tables, etc. ▼, ▲There are mathematical formulas, chemical formulas, tables, etc.▼, ▲There are mathematical formulas, chemical formulas, tables, etc.▼ and ▲There are mathematical formulas, chemical formulas, tables, etc.▼ Indicates one or more groups selected from R_2 and R_3. may be the same. Moreover, in the formula, X represents a hydrogen atom or a chlorine atom. )