JPH0859965A - Resin composition for injection molding and molded article - Google Patents

Abstract

PURPOSE: To obtain the subject composition useful for a connector for optical fibers, having excellent isotropy, surface smoothness and roundness, comprising a polyester-based thermotropic liquid crystal polymer filled with substantially spherical inorganic particles satisfying specific conditions. CONSTITUTION: This resin composition comprises a polyester-based thermotropic liquid crystal polymer filled with substantially spherical inorganic particles (e.g. glass beads or silica) having <=60μm maximum diameter and <=1.5 aspect ratio. The liquid crystal polymer is a polymer for forming an anisotropic melt phase and comprises, for example, an aromatic dicarboxylic acid, an alicyclic dicarboxylic acid, an aromatic diol and an alicyclic diol. The amount of the inorganic particles filled is preferably 30-70wt.% of the total amount including the resin.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a resin composition used for injection molding and an injection molded product formed by the resin composition. More specifically, the present invention can be used for molding precision parts requiring high dimensional accuracy. And a precise injection-molded product formed by the resin composition.

[0002]

2. Description of the Related Art Liquid crystal polymers have high strength and elastic modulus,
Since it is excellent in dimensional stability against temperature change after molding and has good heat resistance and chemical resistance, it is used for manufacturing various injection molded products. However, since the liquid crystal polymer is a resin with a strong anisotropy, various properties greatly differ depending on the direction, which may result in an unbalanced molded product.
Anisotropy in shrinkage behavior occurs in the cooling process after injection,
In many cases, a molded product having a wavy surface was formed. Therefore, conventionally, in injection molding using a liquid crystal polymer, a fibrous filler such as glass fiber, a plate-like filler such as glass flake, an amorphous filler such as silica is filled in the resin, and It is being reduced.
Further, JP-A-58-93759 discloses a technique of using a liquid crystal polymer in which fine hollow spheres are dispersed in order to reduce the anisotropy of mechanical properties of an injection molded product.

[0003]

However, when injection molding is performed using a liquid crystal polymer to which a filler such as glass fiber is added, the anisotropy of resin properties is reduced, and strength, dimensional stability, and chemical resistance are reduced. Although an excellent molded product can be obtained, on the other hand, another problem that the surface property of the molded product is impeded occurs. That is, in the molding of the plate-shaped parts, the surface is uneven due to the influence of the exposed filler,
It is not possible to obtain parts with good surface smoothness, and when molding cylindrical parts, the surface smoothness is impaired due to the influence of the filler that has been exposed, and the circularity of the inner and outer diameters and , It was not possible to obtain parts with high cylindricity. In recent years, high precision is often required for the surface smoothness, roundness, cylindricity, etc. of resin molded products. For example, connectors for optical fibers called ferrules and sleeves (see FIG. 3).
In order to prevent an increase in optical fiber splice loss, the fine cylindrical hole of about 100 μm at the tip should have roundness and cylindricity of several μm or less. However, liquid crystal polymers to which fillers such as glass fibers are added cannot be used for injection molding of such precision parts. On the other hand, although the technique of using a liquid crystal polymer in which micro hollow spheres are dispersed can reduce the anisotropy of the mechanical properties of the molded product, the micro hollow spheres often break during the molding process. It is difficult to control the specific gravity, and in addition, there is a problem that the production of the micro hollow spheres is costly.

An object of the present invention is to solve the above problems,
Precision parts that are required to have various properties such as strength, good isotropy, no waviness on the surface, high surface smoothness, and roundness. It is intended to provide a resin composition for injection molding which can be used for injection molding. Further, good characteristics and extremely high surface smoothness formed by the resin composition,
It is to provide precision molded products that also have roundness.

[0005]

The constitution of the present invention is as follows.
Maximum diameter is 60 μm or less and aspect ratio is 1.5
The resin composition for injection molding comprises the following polyester-based thermotropic liquid crystal polymer filled with substantially spherical inorganic particles. Further, it is a molded article obtained by injection molding a polyester-based thermotropic liquid crystal polymer having a maximum diameter of 60 μm or less and an aspect ratio of 1.5 or less and filled with substantially spherical inorganic particles. Further, the molded product has at least a part having a plate-shaped portion or a cylindrical portion, or has a disk body or a cylindrical body, and in particular, an optical fiber connector, a fuel pump impeller, a hard disk drive. Centering hubs or nozzles for laser beam printers.

The liquid crystal polymer used in the present invention is generally called a thermotropic liquid crystal polymer and is a polymer which exhibits optical anisotropy when melted, that is, forms an anisotropic molten phase. Among them, among them, In particular, it is limited to polyester-based thermotropic liquid crystal polymers capable of obtaining molded products excellent in mechanical properties, moldability, heat resistance, chemical resistance, etc. (in the following description, simply referred to as liquid crystal polymer) . A polymer forming an anisotropic molten phase has a property that polymer molecular chains have a regular parallel arrangement in a molten state (the molecules arranged in such a state are often in a liquid crystal state or a nematic substance of a liquid crystalline substance). Called phase). Such polymers are generally elongated, flat,
It is made from such monomers that are fairly rigid along the long axis of the molecule and usually have multiple chain extension bonds in either coaxial or parallel relationship.

The properties of the anisotropic molten phase can be confirmed by a conventional polarization inspection method using a crossed polarizer. More specifically, the anisotropic molten phase can be confirmed by observing the sample placed on the Leitz hot stage under a nitrogen atmosphere at a magnification of 40 times using a Leitz polarization microscope. The polymer is optically anisotropic. That is, it transmits light when inspected between crossed polarizers. If the sample is optically anisotropic, polarized light will be transmitted even if it is stationary.

Constituent components of the polymer forming the anisotropic molten phase as described above include one or more of aromatic dicarboxylic acids and alicyclic dicarboxylic acids. Aromatic diols, alicyclic diols, One consisting of one or more aliphatic diols One consisting of one or more aromatic hydroxycarboxylic acids Aromatic thiols One consisting of one or more carboxylic acids Aromatic dithiols, aromatic thiols 1 of phenol
One or more, such as aromatic hydroxyamine, one or more of aromatic diamine, and the like. The polymer forming the anisotropic melt phase is a polyester (a) ( a polyester amide consisting of a polyester (c) consisting only of b) and a polythiol ester consisting of a polyester (d) consisting only of a polythiol ester (e) (f) and a polythiol ester consisting of a (g) ) And and are composed of a combination of polyesteramides and the like.

Although not included in the category of the combination of the above components, the polymer forming the anisotropic molten phase includes
Aromatic polyazomethines are included, and specific examples of such polymers include poly (nitrilo-2-methyl-1,4-phenylene nitriloethylidyne-1,4-phenyleneethylidine); poly (nitrilo-2-methyl- 1,4-phenylene nitrilomethylidine-1,4-phenylene methylidine); and poly (nitrilo-2-chloro-1,4-phenylene nitrilomethylidine-1,4-phenylene methylidine). .

Further, although not included in the category of the combination of the above components, polyester carbonate is included as the polymer forming the anisotropic molten phase. Some of these consist essentially of 4-oxybenzoyl units, dioxyphenyl units, dioxycarbonyl units and terephthaloyl units.

The compounds as the constituents of the above (a) to (h) are listed below. Aromatic dicarboxylic acids include terephthalic acid, 4,4'-diphenylcarboxylic acid, 4,4'-
Triphenyldicarboxylic acid, 2,6-naphthalenedicarboxylic acid, diphenylether-4,4'-dicarboxylic acid, diphenoxyethane-4,4'-dicarboxylic acid, diphenoxybutane-4,4'-dicarboxylic acid, diphenylethane- 4,4'-dicarboxylic acid, isophthalic acid, diphenyl ether-3,3'-dicarboxylic acid, diphenoxyethane-3,3'-dicarboxylic acid, diphenylethane-3,3'-dicarboxylic acid, naphthalene-1,6- An aromatic dicarboxylic acid such as dicarboxylic acid, or an aromatic dicarboxylic acid such as chloroterephthalic acid, dichloroterephthalic acid, bromoterephthalic acid, methylterephthalic acid, dimethylterephthalic acid, ethylterephthalic acid, methoxyterephthalic acid or ethoxyterephthalic acid Alkyl,
Examples thereof include alkoxy or halogen substitution products.

The alicyclic dicarboxylic acid may be trans-
1,4-cyclohexanedicarboxylic acid, cis-1,4-
Alicyclic dicarboxylic acids such as cyclohexanedicarboxylic acid and 1,3-cyclohexanedicarboxylic acid, or trans-
1,4- (1-methyl) cyclohexanedicarboxylic acid,
Examples thereof include trans-1,4- (1-chloro) cyclohexanedicarboxylic acid and the like, and alkyl-, alkoxy-, or halogen-substituted products of the above alicyclic dicarboxylic acids.

As the aromatic diol, hydroquinone, resorcin, 4,4'-dihydroxydiphenyl,
4,4'-dihydroxytriphenyl, 2,6-naphthalene diol, 4,4'-dihydroxydiphenyl ether, bis (4-hydroxyphenoxy) ethane, 3,
3'-dihydroxydiphenyl, 3,3'-dihydroxydiphenyl ether, 1,6-naphthalene diol,
2,2-bis (4-hydroxyphenyl) propane,
Aromatic diols such as 2,2-bis (4-hydroxyphenyl) methane, chlorohydroquinone, methylhydroquinone, 1-butylhydroquinone, phenylhydroquinone, methoxyhydroquinone, phenoxyhydroquinone: 4-chlororesorcin, 4-methylresorcin, etc. Examples thereof include alkyl, alkoxy or halogen-substituted aromatic diols.

As the alicyclic diol, trans-1,
4-cyclohexanediol, cis-1,4-cyclohexanediol, trans-1,4-cyclohexanedimethanol, cis-1,4-cyclohexanedimethanol, trans-1,3-cyclohexanediol, cis-1,2-cyclohexane Diol, trans-1,3
An alicyclic diol such as cyclohexanedimethanol, or an alkyl of the above alicyclic diol such as trans-1,4 (1-methyl) cyclohexanediol or trans-1,4- (1-chloro) cyclohexanediol,
Examples thereof include alkoxy or halogen substitution products.

Examples of the alicyclic diol include linear or branched alicyclic diols such as ethylene glycol, 1,3-propanediol, 1,4-butanediol and neopentyl glycol.

As the aromatic hydroxycarboxylic acid, 4
-Hydroxybenzoic acid, 3-hydroxybenzoic acid, 6-
Aromatic hydroxycarboxylic acids such as hydroxy-2-naphthoic acid and 6-hydroxy-1-naphthoic acid, or 3-
Methyl-4-hydroxybenzoic acid, 3,5-dimethyl-
4-hydroxybenzoic acid, 2,6-dimethyl-4-hydroxybenzoic acid, 3-methoxy-4-hydroxybenzoic acid, 3,5-dimethoxy-4-hydroxybenzoic acid, 6
-Hydroxy-5-methyl-2-naphthoic acid, 6-hydroxy-5-methoxy-2-naphthoic acid, 3-chloro-
4-hydroxybenzoic acid, 2-chloro-4-hydroxybenzoic acid, 2,3-dichloro-4-hydroxybenzoic acid, 3,5-dichloro-4-hydroxybenzoic acid, 2,
5-dichloro-4-hydroxybenzoic acid, 3-bromo-
4-hydroxybenzoic acid, 6-hydroxy-5-chloro-2-naphthoic acid, 6-hydroxy-7-chloro-2-
Naphthoic acid, 6-hydroxy-5,7-dichloro-2-
Examples thereof include alkyl, alkoxy or halogen substitution products of aromatic hydroxycarboxylic acid such as naphthoic acid.

As the aromatic mercaptocarboxylic acid, 4
-Mercaptobenzoic acid, 3-mercaptobenzoic acid, 6-
Examples thereof include mercapto-2-naphthoic acid and 7-mercapto-2-naphthoic acid.

As the aromatic diol, benzene-1,
4-dithiol, benzene-1,3-dithiol, 2,
Examples thereof include 6-naphthalene-dithiol and 2,7-naphthalene-dithiol. As the aromatic mercaptophenol, 4-mercaptophenol, 3-mercaptophenol, 6-mercaptophenol, 7-
Examples thereof include mercaptophenol and the like.

As the aromatic hydroxyamine and aromatic diamine, 4-aminophenol, N-methyl-4-aminophenol, 1,4-phenylenediamine, N-methyl-1,4-phenylenediamine, N, N '. -Dimethyl-1,4-phenylenediamine, 3-aminophenol, 3-methyl-4-aminophenol, 2-chloro-
4-aminophenol, 4-amino-1-naphthol,
4-amino-4'hydroxydiphenyl, 4-amino-
4'-hydroxydiphenyl ether, 4-amino-4
′ -Hydroxydiphenylmethane, 4-amino-4′-
Hydroxydiphenyl sulfide, 4,4'-diaminophenyl sulfide (thiodianiline), 4,4'-diaminodiphenyl sulfone, 2,5-diaminotoluene, 4,4'-ethylene dianiline, 4,4'-diaminodiphenoxyethane , 4,4'-diaminodiphenylmethane (methylenedianiline), 4,4'-diaminodiphenyl ether (oxydianiline) and the like.

The above polymer (a) comprising the above components
(h), depending on the constituent components and the composition ratio in the polymer, depending on the sequence distribution, there are those that form an anisotropic melt phase and those that do not, but the polymer used in the present invention is
Of the above polymers, it is limited to those that form an anisotropic melt phase.

The polyesters (a), (b), (c) and the polyesteramide (h), which are polymers forming an anisotropic melt phase suitable for use in the present invention, are condensed to give the desired repeating It can be produced by a variety of ester forming methods that can react organic monomer compounds having a functional group that forms a unit. For example, the functional groups of these organic monomer compounds may be carboxylic acid groups, hydroxyl groups, ester groups, acyloxy groups, acid halides, amine groups and the like. The organic monomer compound can be reacted by a molten acidolysis method without the presence of a heat exchange fluid. In this method, the monomers are first heated together to form a molten solution of the reactants. As the reaction continues, solid polymer particles become suspended in the liquid. Vacuum may be applied to facilitate removal of volatiles by-produced in the final stage of the condensation, such as acetic acid or water.

The slurry polymerization method can also be employed to form a wholly aromatic polyester suitable for use in the present invention. In this way, the solid product is obtained in suspension in the heat exchange medium.

Whichever of the above-mentioned melt acidolysis method and slurry polymerization method is adopted, the organic monomer reactant for inducing a wholly aromatic polyester is in a modified form in which the hydroxyl group of such a monomer is esterified at room temperature ( That is, it can be subjected to a reaction (as a lower acyl ester). The lower acyl group preferably has about 2 to 4 carbon atoms. Preferably, the acetic acid ester of such an organic monomer reactant is subjected to the reaction.

Representative examples of catalysts that can be optionally used in either the melt acidolysis method or the slurry method are dialkyltin oxide (eg, dibutyltin oxide), diaryltin oxide, titanium dioxide, antimony trioxide, and alkoxytitanium silicate. , Titanium alkoxide, alkali and alkaline earth metal salts of carboxylic acids (eg zinc acetate), Lewis acids (eg BF ₃ ), hydrogen halides (eg HCl) and other gaseous acid catalysts. . The amount of catalyst used is generally about 0.001 to 1% by weight, especially about 0.01 to 0.2, based on the total weight of the monomers.
% By weight.

The wholly aromatic polymers suitable for use in the present invention tend to be substantially insoluble in common solvents and are therefore unsuitable for solution processing. However, as already mentioned, these polymers can be easily processed by conventional melt processing methods. Particularly preferred wholly aromatic polymers are somewhat soluble in pentafluorophenol.

The wholly aromatic polyesters suitable for use in the present invention generally have a weight average molecular weight of about 2000 to 200,000, preferably about 10,000 to 50,000, and particularly preferably about 20,000.
25,000. On the other hand, suitable wholly aromatic polyesteramides generally have a molecular weight of about 5000 to 50000, preferably about
It is 10000 to 30000, for example 15000 to 17000. The measurement of such a molecular weight can be carried out by a standard measurement method which does not involve solution formation of gel permeation chromatography and other polymers, for example, by quantifying the end groups of a compression-molded film by infrared spectroscopy. The molecular weight can also be measured by using a pentafluorophenol solution and using a light scattering method.

The above-mentioned wholly aromatic polyesters and polyester amides usually have a concentration of at least about 2.0 dl / g, for example, about 2.0-10.0 dl / g when dissolved in pentafluorophenol at a concentration of 0.1% by weight at 60 ° C. The logarithmic viscosity (IV) of is shown.

The polymer forming the anisotropic melt phase used in the present invention is an aromatic polyester and an aromatic polyesteramide, or a polyester partially containing an aromatic polyester and an aromatic polyesteramide in the same molecular chain. preferable. Preferred examples of the compounds constituting them are 2,6-naphthalenedicarboxylic acid, 2,6
Naphthalene compounds such as dihydroxynaphthalene, 1,4-dihydroxynaphthalene and 6-hydroxy-2-naphthoic acid, 4,4′-diphenyldicarboxylic acid, 4,
Biphenyl compounds such as 4'-dihydroxybiphenyl,
Para-substituted benzenes such as p-hydroxybenzoic acid, terephthalic acid, hydroquinone, p-aminophenol, p-phenylenediamine and the like represented by the following general formula (A), (B) or (C) Compounds and their nucleus-substituted benzene compounds (substituents are selected from chlorine, bromine, methyl, phenyl, 1-phenylethyl), meta-substituted benzene compounds such as isophthalic acid and resorcin.

Embedded image (However, in Chemical formula 1, X is alkylene (C ₁ -C
₄₎ alkylidene, -O -, - SO -, - SO 2 -,
Represents a group selected from —S— and —CO—, and Y represents (CH
_{2) n - (n = 1~4} ), - O (CH 2) n O- (n =
A group selected from 1 to 4) is shown. )

A preferred example of the polyester partially containing the above-mentioned constituents in the same molecular chain is polyalkylene terephthalate having an alkyl group having 2 to 4 carbon atoms. Further, among the above-mentioned constituents, those containing one or more kinds of compounds selected from naphthalene compounds, biphenyl compounds and para-substituted benzene compounds as essential constituents are more preferable examples. Among the p-position-substituted benzene compounds, p-hydroxybenzoic acid, methylhydroquinone and 1-phenylethylhydroquinone are particularly preferable examples.

Specific combinations of the constituents include:
The following chemical formulas 2 to 8 can be mentioned.

Embedded image

[Chemical 3]

[Chemical 4]

[Chemical 5]

[Chemical 6]

[Chemical 7]

Embedded image In Chemical Formulas 2 to 8, Z is —Cl, —Br, —C.
H represents a substituent selected from H ₃ , and X represents alkylene (C ₁
-C _4), alkylidene, -O -, - SO -, - SO 2
A substituent selected from-, -S- and -CO- is shown.

Among the polyesters forming the anisotropic melt phase used in the present invention, particularly preferable ones are naphthalene such as 6-hydroxy, 2-naphthoyl, 2,6-dihydroxynaphthalene and 2,6-dicarboxynaphthalene. A partially containing repeating unit is contained in an amount of about 10 mol% or more. Preferred polyesteramides are those containing repeating units of the naphthalene moieties described above and moieties consisting of 4-aminophenol or 1,4-phenylenediamine. Specifically, it is as shown in (1) to (6) below.

(1) A polyester essentially consisting of repeating units (A) and (B) shown in the following chemical formula (9).

[Chemical 9] This polyester contains about 10 to 90 mol% of unit (A) and about 10
Containing ~ 90 mol% of unit (B). (A) In the embodiment, the unit (A) is about 65 to 85 mol%, preferably about 70 to 80 mol%.
Is present up to an amount of (eg about 75 mol%). In another embodiment, the unit (B) is about 15-35 mol%, preferably about 20-35%.
It is present in much lower concentrations of 30 mol%. Further, at least a part of the hydrogen atoms bonded to the ring may be a group consisting of an alkyl group having 1 to 4 carbon atoms, an alkoxy group having 1 to 4 carbon atoms, halogen, phenyl, substituted phenyl, and combinations thereof. It may be substituted with a substituent selected from

(2) A polyester essentially consisting of repeating units (A), (B) and (C) shown in the following chemical formula (10).

[Chemical 10] This polyester contains about 30 to 70 mol% of units (A). The polyester is preferably about 40-60 mol% units (A), about 20-30 mol% units (B), and about 20
Contains ~ 30 mol% of unit (C). Further, at least a part of the hydrogen atoms bonded to the ring may be a group consisting of an alkyl group having 1 to 4 carbon atoms, an alkoxy group having 1 to 4 carbon atoms, halogen, phenyl, substituted phenyl, and combinations thereof. It may be substituted with a substituent selected from

(3) consists essentially of repeating units (A), (B), (C) and (D) shown in Chemical Formula 11 below, and has units (A)
About 20 to 60 mol%, unit (B) about 5 to 18 mol%, unit
A polyester containing (C) in an amount of about 5 to 35 mol% and units (D) in an amount of about 20 to 40 mol%.

[Chemical 11] (However, in Chemical formula 11, R means methyl, chloro, bromo, or a combination thereof, and is a substituent for a hydrogen atom on an aromatic ring.) This polyester preferably contains about 35 to 45 mol% of units. (A) contains about 10 to 15 mol% of units (B), about 15 to 25 mol% of units (C), and about 25 to 35 mol% of units (D). However, the total molar concentration of the units (B) and (C) is substantially equal to the molar concentration of the unit (D). Moreover, at least a part of the hydrogen atoms bonded to the ring may have 1 to 4 carbon atoms.
May be substituted with a substituent selected from the group consisting of an alkyl group having 1 to 4 carbon atoms, an alkoxy group having 1 to 4 carbon atoms, halogen, phenyl, substituted phenyl, and combinations thereof. This fully aromatic polyester, when dissolved in pentafluorophenol at a concentration of 0.3 _W / _V % at 60 ° C,
Generally, at least 2.0 dl / g or more (for example, 2.0 to 10.
The logarithmic viscosity of 0 dl / g) is shown.

(4) Essentially, the repeating units (A), (B), and (C) represented by the following chemical formula 12 are represented by the general formula [-O-Ar-O].
-] (Ar represents a divalent group containing at least one aromatic ring), (D) a general formula [-CO-Ar'-CO-] (Ar 'is at least one Of a divalent group containing an aromatic ring) of about 20 to 40 mol% of the unit (A) and more than 10 mol% of the unit (B) to about 50 mol% of the unit (B). Below, the unit (C) is more than 5 mol% and about 30 mol% or less, and the unit
A polyester containing (D) in an amount of more than 5 mol% and not more than about 30 mol%.

[Chemical 12] The polyester is preferably about 20 to 30 mol% (eg, about 25 mol%) units (A), about 25 to 40 mol% (eg, about 35 mol%) units (B), about 15 to about 25 mol% (eg, about 20 mol%) units (C), and about 15-25 mol%
(For example, about 20 mol%) of the unit (D). Also,
At least some of the hydrogen atoms bonded to the ring are optionally selected from the group consisting of an alkyl group having 1 to 4 carbon atoms, an alkoxy group having 1 to 4 carbon atoms, halogen, phenyl, substituted phenyl, and combinations thereof. It may be substituted with a substituent. The units (C) and (D) have symmetrically arranged divalent bonds on one or more aromatic rings that connect these units to the units on both sides in the polymer main chain (eg, naphthalene ring). When present above, they are preferably symmetrical with respect to each other in the para position or arranged on a diagonal ring). However, asymmetric units such as those derived from resorcinol and isophthalic acid can be used. The preferred dioxyaryl unit (C) has the structure of chemical formula 13 below, and the preferred dicarboxyaryl unit (D) has the structure of chemical formula 14 below.

[Chemical 13]

Embedded image

(5) The repeating unit (A) essentially consisting of the following chemical formula 15 and (B) the general formula [-O-Ar-O-] (A
r means a divalent group containing at least one aromatic ring)
A dioxyaryl unit represented by the formula (C) [--CO
-Ar'-CO-] (Ar 'means a divalent group containing at least one aromatic ring) and comprises about 10 to 90 mol% of the unit (A). A polyester containing (B) in an amount of 5 to 45 mol% and units (C) in an amount of 5 to 45 mol%.

[Chemical 15] The polyester preferably contains about 20-80 mol% units (A), about 10-40 mol% units (B), and about 10-40 mol% units (C), and more preferably , About 60-80
Mol% units (A), and about 10-20 mol% units (B),
And it contains about 10 to 20 mol% of unit (C). Further, at least a part of the hydrogen atoms bonded to the ring may be a group consisting of an alkyl group having 1 to 4 carbon atoms, an alkoxy group having 1 to 4 carbon atoms, halogen, phenyl, substituted phenyl, and combinations thereof. It may be substituted with a substituent selected from The preferred dioxyaryl unit (B) has the structure of the following chemical formula 16, and the preferred dicarboxyaryl unit (C) is the following chemical formula 17
It has the following structure.

Embedded image

[Chemical 17]

(6) Essentially the repeating unit (A) represented by the following chemical formula 18, and (B) the general formula [-CO-A-CO-].
(A represents a divalent group containing at least one aromatic ring or a divalent trans-cyclohexane group), (C) a general formula [-Y-A _r -Z
-] (A _r is a divalent group containing at least one aromatic ring, Y
Represents O, NH or NR, Z represents NH or NR, respectively, and R represents an alkyl group having 1 to 6 carbon atoms or an aryl group), and (D) a general formula [-O -A _r ′ -O-] (A _r ′ means a divalent group containing at least one aromatic ring) and contains about 10 to 90 mol% of the unit (A). , The unit (B) is about 5 to 45 mol%, the unit (C) is about 5 to 45 mol%,
And a polyesteramide containing units (D) in an amount of about 0 to 40 mol%.

Embedded image In this polyesteramide, at least some of the hydrogen atoms bonded to the ring may have 1 to 4 carbon atoms.
May be substituted with a substituent selected from the group consisting of an alkyl group having 1 to 4 carbon atoms, an alkoxy group having 1 to 4 carbon atoms, halogen, phenyl, substituted phenyl, and combinations thereof. The preferred dicarboxyaryl unit (B) is
Preferred units having the structure of the following chemical formula 19
(C) has a structure of the following chemical formula 20 or 21, and preferable dioxyaryl unit (D) has a structure of the following chemical formula 22.

[Chemical 19]

Embedded image

[Chemical 21]

[Chemical formula 22]

Furthermore, in the polymer forming the anisotropic melt phase of the present invention, a part of one polymer chain is composed of the segments of the polymer forming the anisotropic melt phase described above, and the rest Polymers in which the part of (1) is composed of a segment of a thermoplastic resin that does not form an anisotropic molten phase are also included.

The polymers forming the anisotropic molten phase of the present invention may be used alone or in combination of two or more. Further, the polymer that forms the anisotropic melt phase may contain one or more thermoplastic resins and thermosetting resins that do not form the anisotropic melt phase. At this time, the polymer forming the anisotropic melt phase and the resin not forming the anisotropic melt phase may be compatible or incompatible.

As the thermoplastic resin which does not form an anisotropic molten phase, for example, polyethylene, polypropylene, polybutylene, polybutadiene, polyisoprene, polyvinyl acetate, polyvinyl chloride, polyvinylidene chloride, polystyrene, acrylic resin, ABS resin, AS resin, BS resin, polyurethane, silicone resin, polyacetal,
Polycarbonate, polyethylene terephthalate, polybutylene terephthalate, aromatic polyester, polyamide, polyacrylonitrile, polyvinyl alcohol,
Polyvinyl ether, polyether imide, polyamide imide, polyether ether imide, polyether ether ketone, polyether sulfone, polysulfone, polyphenylene sulfide, polyphenylene oxide and the like can be mentioned, as the thermosetting resin other than the liquid crystal polymer, For example, phenolic resin, epoxy resin,
Melamine resin, urea resin, unsaturated polyester resin,
An alkyd resin etc. can be mentioned.

As the inorganic particles to be filled in the liquid crystal polymer, glass beads, silica, calcium carbonate and the like can be mainly mentioned, and these may be used alone or in combination of two or more kinds. Is also good. The inorganic particles used in the present invention must have an aspect ratio (ratio of major axis to minor axis of particle) of 1.5 or less and be substantially spherical, and maximum diameter of 60 μm or less. The fact that the particles are substantially spherical means that they are completely spherical (true spherical).
In addition to the above-mentioned particles, it means that the particles have a substantially spherical or ellipsoidal outer shape. On the other hand, having a maximum diameter of 60 μm or less means particles having a diameter larger than 60 μm regardless of the particle size distribution. It means that the particles are not contained, and particles having a size of 60 μm or more are removed by a method such as classification. In the present invention, the aspect ratio of the inorganic particles is required to be 1.5 or less, but the anisotropy is reduced, and the higher surface smoothness,
In order to obtain roundness and cylindricity, it is preferable that the spherical shape is 1.2 or less, which is close to a spherical shape. Further, the maximum diameter is required to be 60 μm or less, but similarly, in order to reduce anisotropy and obtain higher surface smoothness, roundness, and cylindricity, it is 40 μm or less. Preferably there is. The filling amount of the inorganic particles is not particularly limited, but in order to reduce anisotropy without deteriorating properties such as strength and dimensional stability of the resin, 30 to 70% by weight of the total weight including the resin is filled. Preferably. If it is less than 30% by weight, the effect of reducing anisotropy will not be exhibited. On the contrary, if it exceeds 70% by weight, the fluidity of the resin will be deteriorated, the moldability will be deteriorated, and the mechanical properties of the molded article will be deteriorated. It is not preferable. From the viewpoint of effectively reducing anisotropy while maintaining good moldability, a more preferable range of the filling amount is 40 to 60% by weight.

Further, if necessary, the liquid crystal polymer filled with inorganic particles may include, for example, stabilizers such as plasticizers, antioxidants and ultraviolet absorbers, flame retardants, coloring agents such as dyes and pigments, and foaming agents. Further, a divinyl compound, a crosslinking agent such as a peroxide or a vulcanizing agent, and a low molecular weight organic compound as a lubricant for improving fluidity or releasability can be added.

[0043]

The substantially spherical inorganic particles having a maximum diameter of 60 μm or less and an aspect ratio of 1.5 or less, which are filled in the resin, have a high ratio around the liquid crystal polymer molecules melted during injection molding. It exists and prevents each molecular chain from flowing in the same direction, and reduces the anisotropy of the characteristics of the molded product. At this time, the inorganic particles in the molten resin do not agglomerate to form coarse protrusions due to the interaction of the shape and size thereof, and do not significantly protrude to the outer periphery of the molded product, and thus contact the mold of the molded product. The surface property of the resin is not hindered. Therefore, the molded product exhibits a high surface smoothness (a surface having less unevenness in the case of plate-shaped or disk-shaped parts, a high roundness and cylindricity in the case of cylinders and columnar parts). Therefore, precision parts such as optical fiber connectors, fuel pump impellers, centering hubs for hard disk drives, and nozzles for laser beam printers, which are obtained by injection-molding a resin molded product filled with such specially shaped inorganic particles, are favorable. It has characteristics (strength, heat resistance, etc.) and extremely high roundness and cylindricity.

[0044]

【Example】

[Example 1] <Production of liquid crystal polymer> 4-acetoxybenzoic acid 108
After stirring 1 part by weight, 460 parts by weight of 6-acetoxy-2-naphthoic acid, 166 parts by weight of isophthalic acid, and 194 parts by weight of 1,4-diacetoxybenzene, the mixture was placed in a reactor equipped with a nitrogen introducing tube and a distilling tube. Charge and heat the mixture to 260 ° C. under a stream of nitrogen. While distilling acetic acid from the reactor, the mixture was vigorously stirred at 260 ° C. for 2.5 hours and then at 280 ° C. for 3 hours. Furthermore, after raising the temperature to 320 ° C. and stopping the introduction of nitrogen, the pressure inside the reactor was gradually reduced, the pressure was lowered to 0.1 mmHg after 15 minutes, and the mixture was stirred at this temperature and pressure for 1 hour. The liquid crystal polymer of Example 1 was obtained. The structure and composition of the obtained liquid crystal polymer are shown below.
There are three.

[Chemical formula 23] The intrinsic viscosity of the obtained liquid crystal polymer in a 0.1% by weight solution of pentafluorophenol at 60 ° C. was measured and the result was 5.0. <Manufacture of molded product> The obtained liquid crystal polymer has a maximum diameter of 4
50 micron glass beads with an aspect ratio of 1.1
wt% filling, and the resin composition, Nissei injection molding machine F
Cylinder part 300 ° C, nozzle 3 using S-75N
Injection molding was performed under the molding conditions of 00 ° C., mold temperature 120 ° C. and injection pressure 400 kg / cm ² , and the disc body shown in FIG. 1 and FIG.
Two types of molded articles of Example 1 having the cylindrical body shown in FIG. In addition, in the injection molding of a disk body, the diameter is 20.0 mm.
The mold used was adjusted so that φ and thickness were 0.8 mm, and the gate was located at the center of the disk. On the other hand, in the injection molding of a cylindrical body, the outer diameter is 4.6 mmφ and the inner diameter is 3.0 mm.
φ and length are adjusted to 10.0 mm, and a disk part with a diameter larger than the cylinder diameter is adjacent to the outside of one end of the cylindrical part, and the resin is uniformly distributed inside the cylinder from one end along the circumference. A mold adjusted to be injected was used. Furthermore, under the same conditions as the molding of discs and cylinders,
The optical fiber connector (ferrule) of Example 1 having the shape shown in FIG. 3 was molded. <Evaluation of Molded Article> After leaving the obtained molded article for 48 hours in a temperature-controlled room at 23 ° C. and 50%, the surface runout of the disk body, the cylindricity of the cylinder body, and the connection characteristics of the ferrule were measured. Each was evaluated. The evaluation methods of surface wobbling (surface irregularity), cylindricity, and connection characteristics are as follows. "Evaluation of surface runout" Using a rank-tailor Hobson's roundness measuring device (Talylonde 300), the unevenness of the surface (maximum height and The difference in the minimum height) was accurately measured along the circumference, and the value was defined as the surface runout. "Evaluation of cylindricity" Using the roundness measuring device (Talylond 300) manufactured by Rank Taylor Hobson Co., the difference between the maximum inner diameter and the minimum inner diameter is obtained at the positions of about 2 mm, 5 mm, and 8 mm from one end of the cylindrical body in FIG. The average value of the three values was calculated as the cylindricity. "Connection characteristics" Using an LED with a wavelength of 0.85 μm as a light source
The magnitude of the splice loss was determined when a GI type quartz fiber having an outer diameter of 125 μm, a core diameter of 50 μm and a length of 1 km was used as a dummy fiber. Then, those having a connection loss of less than 0.4db were evaluated as good connection characteristics, those having a connection loss of 0.4db or more and less than 0.7db were acceptable, and those having a connection loss of 0.7db or more were evaluated as defective. In the evaluation of the connection characteristics, the connection surface was adhered with a cyanoacrylate-based instant adhesive, and the abutting end surface was diamond-polished. The evaluation results of surface wobbling, cylindricity, and connection characteristics are shown in Table 1 together with the characteristics of the filler.

Example 2 <Production of Liquid Crystal Polymer> The same liquid crystal polymer as in Example 1 was used. <Production of molded article> Inorganic particles to be filled in the liquid crystal polymer,
In the same manner as in Example 1 except that glass beads having a maximum diameter of 10 μm and an aspect ratio of 1.1 were used, three molded articles of Example 2, namely a disk body, a cylindrical body, and a ferrule, were obtained. . The obtained molded product was evaluated in the same manner as in Example 1. The evaluation results are shown in Table 1 together with the characteristics of the filler.

Example 3 <Production of Liquid Crystal Polymer> The same liquid crystal polymer as in Example 1 was used. <Production of molded article> Inorganic particles to be filled in the liquid crystal polymer,
In the same manner as in Example 1 except that silica particles having a maximum diameter of 1 μm and an aspect ratio of 1.1 were changed, three molded articles of Example 3, a disk body, a cylindrical body, and a ferrule, were obtained. . The obtained molded product was evaluated in the same manner as in Example 1. The evaluation results are shown in Table 1 together with the characteristics of the filler.

Comparative Example 1 <Production of Liquid Crystal Polymer> The same liquid crystal polymer as in Example 1 was used. <Production of molded article> Inorganic particles to be filled in the liquid crystal polymer,
In the same manner as in Example 1 except that glass fiber having a diameter of 9 μm and a length of 3 mm (apparent aspect ratio (length / diameter) = 333.3) was used, a disc body, a cylinder body, and a ferrule A molded article of Comparative Example 1 was obtained. The obtained molded product was evaluated in the same manner as in Example 1. The evaluation results are shown in Table 1 together with the characteristics of the filler.

Comparative Example 2 <Production of Liquid Crystal Polymer> The same liquid crystal polymer as in Example 1 was used. <Production of molded article> Inorganic particles to be filled in the liquid crystal polymer,
In the same manner as in Example 1 except that glass beads having a maximum diameter of 80 μm and an aspect ratio of 1.1 were changed, three molded articles of Comparative Example 2 of a disk body, a cylindrical body, and a ferrule were obtained. . The obtained molded product was evaluated in the same manner as in Example 1. The evaluation results are shown in Table 1 together with the characteristics of the filler.

Comparative Example 3 <Production of Liquid Crystal Polymer> The same liquid crystal polymer as in Example 1 was used. <Production of molded article> Inorganic particles to be filled in the liquid crystal polymer,
In the same manner as in Example 1 except that glass beads having a maximum diameter of 100 μm and an aspect ratio of 1.2 were changed, three molded articles of Comparative Example 3 including a disk body, a cylindrical body, and a ferrule were obtained. . The obtained molded product was evaluated in the same manner as in Example 1. The evaluation results are shown in Table 1 together with the characteristics of the filler.

[0050]

[Table 1]

In this embodiment, an example in which each of the disk body, the cylindrical body, and the optical fiber connector (ferrule) is injection-molded has been described. However, the injection-molding resin composition of the present invention contains these components. High surface smoothness, roundness, and cylindricity can be exhibited not only in the case of injection molding but also in the case of injection molding of any shape. Therefore, in addition to optical fiber connectors (ferrules), particularly high surface smoothness, roundness, and cylindricity are required for fuel pump impellers for automobiles, centering hubs for hard disk drives, nozzles for laser beam printers, etc. It can be suitably used for molding parts.

[0052]

As described above, according to the present invention, in the injection molding of a liquid crystal polymer, it is possible to improve the isotropy of the molded product and to provide the molded product with high surface smoothness, roundness and cylindricity. Two conflicting requirements of expression can be met simultaneously. Therefore, injection of precision parts that requires high strength and elasticity, good dimensional stability, heat resistance, chemical resistance as well as isotropy of characteristics, high surface smoothness, roundness, cylindricity, etc. Molding is also possible. Therefore, precision parts such as optical fiber connectors, fuel pump impellers, centering hubs for hard disk drives, and nozzles for laser beam printers obtained by the present invention are
Since it combines good characteristics with extremely high roundness and cylindricity, it does not require any further finishing after molding and has excellent reliability when used.

[Brief description of drawings]

FIG. 1 is an explanatory view showing the shapes of disc bodies formed in Examples and Comparative Examples.

FIG. 2 is an explanatory view showing a shape of a cylindrical body molded in Examples and Comparative Examples.

FIG. 3 is an explanatory diagram showing the shape of an optical fiber connector (ferrule).

[Explanation of symbols]

 1 ... Fiber insertion hole, 2 ... Micro cylindrical hole.

Claims (5)

[Claims] 1. A resin composition for injection molding comprising a polyester thermotropic liquid crystal polymer filled with substantially spherical inorganic particles having a maximum diameter of 60 μm or less and an aspect ratio of 1.5 or less. 2. A molded article obtained by injection molding a polyester-based thermotropic liquid crystal polymer having a maximum diameter of 60 μm or less and an aspect ratio of 1.5 or less and filled with substantially spherical inorganic particles. 3. The molded product according to claim 2, wherein the molded product has a plate-shaped portion or a tubular portion in at least a part thereof. 4. The molded product according to claim 2, which is a disc or a cylinder. 5. The molded product according to claim 2, which is a connector for an optical fiber, a fuel pump impeller, a centering hub for a hard disk drive, or a nozzle for a laser beam printer.