KR20230032907A - Liquid crystal polymer composition - Google Patents

Abstract

The objective of the present invention is to provide a liquid crystal polymer composition capable of reducing the generation of particles during ultrasonic cleaning of molded articles and suppressing the occurrence of warpage in the molded articles. The present invention relates to a liquid crystal polymer composition including: 100 parts by mass of a liquid crystal polymer; 1 to 50 parts by mass of titanium oxide; and 1 to 50 parts by mass of mica, wherein the ratio of the content (parts by mass) of titanium oxide to the content (parts by mass) of mica is 0.1 to 10.

Description

Liquid crystal polymer composition {LIQUID CRYSTAL POLYMER COMPOSITION}

The present invention relates to a liquid crystal polymer composition in which generation of particles during ultrasonic cleaning is reduced and warpage of a molded article is suppressed.

Since liquid crystal polymers are excellent in mechanical properties, moldability, chemical resistance, gas barrier properties, moisture resistance, electrical properties, etc., they are used for parts in a wide variety of fields. In particular, because of its excellent heat resistance and thin moldability, its use for electronic parts such as precision instruments is expanding.

On the other hand, it is known that molded articles of liquid crystal polymers experience a phenomenon (hereinafter referred to as "fibrillation") in which the surface of the resin is peeled off and fuzz occurs due to ultrasonic cleaning or sliding with other members. In the case of precision instruments, especially optical instruments with lenses, a little dust or dirt affects the performance of the instrument. For example, in parts used in optical devices such as camera modules, if small dust, oil, dirt, or the like adheres to a lens, it causes a significant deterioration in the optical characteristics of the camera module.

For the purpose of preventing such deterioration in optical characteristics, components constituting a camera module such as a lens barrel, a mount holder, a CMOS (image sensor) frame, a shutter, and a shutter bobbin (hereinafter referred to as "for camera modules") Also referred to as "parts") is ultrasonically cleaned before assembly to remove small dust and dirt adhering to the surface.

However, the surface of a molded article made of a liquid crystal polymer composition is easily peeled off, and when ultrasonically cleaned, the surface is peeled off and raised fibrillation is likely to occur. In addition, in this fibrillated portion, small powder and dust (hereinafter referred to as particles) made of the resin composition tend to be generated. Then, even if the generated particles are very small, there is a problem that they become foreign matter when assembling the camera module or when the camera is used, and significantly degrades the optical characteristics of the camera module.

As a liquid crystal polymer composition suppressing particle generation, a resin composition in which a specific filler (talc, glass fiber, carbon black, etc.) or an olefin-based copolymer is contained in a liquid crystal polymer has been proposed (Patent Documents 1 to 6).

Japanese Patent No. 5826411 Japanese Unexamined Patent Publication No. 2015-021110 Japanese Unexamined Patent Publication No. 2015-000949 Japanese Unexamined Patent Publication No. 2012-193270 Japanese Unexamined Patent Publication No. 2009-242453 Japanese Unexamined Patent Publication No. 2009-242456

However, for these, the wettability of the inorganic filler and the liquid crystal polymer was poor, and the effect of suppressing particle generation when ultrasonically cleaned was insufficient. In addition, there was a problem that warpage occurred in molded articles depending on the filler to be incorporated.

Accordingly, there has been a demand for a liquid crystal polymer composition in which the generation of particles is reduced during ultrasonic cleaning and the occurrence of warpage in molded articles is reduced. An object of the present invention is to provide a liquid crystal polymer composition capable of reducing the generation of particles during ultrasonic cleaning of molded articles and suppressing the occurrence of warpage in molded articles.

As a result of intensive studies in view of the above problems, the present inventors have found that when a molded article of a liquid crystal polymer composition is ultrasonically cleaned by containing titanium oxide and mica in a specific ratio with respect to the liquid crystal polymer, the generation of particles is reduced and the warpage is improved. found out, and came to complete this invention.

That is, the present invention includes the following preferred aspects.

[1] 100 parts by mass of a liquid crystal polymer, 1 to 50 parts by mass of titanium oxide, and 1 to 50 parts by mass of mica, the ratio of the content of titanium oxide (parts by mass) to the content (parts by mass) of mica is 0.1 to 10 , liquid crystal polymer composition.

[2] The liquid crystal polymer composition according to [1], wherein the titanium oxide has an average particle diameter of 0.5 μm or less.

[3] The liquid crystal polymer has formula (I) and formula (II)

[Formula 1]

The liquid crystal polymer composition according to [1] or [2], which is a liquid crystal polyester resin containing a repeating unit represented by

[4] The liquid crystal polymer has formulas (I) to (IV)

[Formula 2]

[In the formula, Ar ₁ and Ar ₂ each represent a divalent aromatic group]

The liquid crystal polymer composition according to any one of [1] to [3], which is a wholly aromatic liquid crystal polyester resin composed of repeating units represented by

[5] In the repeating units represented by formulas (III) to (IV), Ar ₁ and Ar ₂ are each independently of each other, and formulas (1) to (4)

[Formula 3]

The liquid crystal polymer composition according to [4], each of which is one or more repeating units selected from aromatic groups represented by .

[6] The repeating unit represented by formula (III) is a repeating unit in which Ar ₁ is an aromatic group represented by formula (1), and the repeating unit represented by formula (IV) is a repeating unit in which Ar ₂ is an aromatic group represented by formula (1). The liquid crystal polymer composition according to [4] or [5], which is a repeating unit that is a unit and/or an aromatic group represented by Formula (3).

[7] The liquid crystal polymer composition according to any one of [1] to [6], further containing graphite.

[8] A molded article composed of the liquid crystal polymer composition according to any one of [1] to [7].

[9] The molded article according to [8], wherein the molded article is a component constituting one type selected from the group consisting of connectors, switches, relays, capacitors, coils, transformers, camera modules, and antennas.

Since the liquid crystal polymer composition of the present invention can reduce particle generation when molded articles are ultrasonically cleaned, and suppress the occurrence of warpage in molded articles, it is suitable for molding parts requiring ultrasonic cleaning, especially electronic parts. It can be used suitably as a resin for use.

BRIEF DESCRIPTION OF THE DRAWINGS Fig. 1 shows a schematic view of a planar test piece prepared for the measurement of warpage amount.

The liquid crystal polymer (hereinafter also referred to as LCP) used in the liquid crystal polymer composition of the present invention is a polyester or polyesteramide that forms an anisotropic molten phase, and is a thermotropic liquid crystal polyester or thermotropic liquid crystal polyester in the art. It is not particularly limited as long as it is called an amide.

The properties of the anisotropic molten phase can be confirmed by a conventional polarization inspection method using an orthogonal polarizer. More specifically, confirmation of the anisotropic molten phase can be performed by using a Leitz polarization microscope and observing a sample placed on a Leitz hot stage under a nitrogen atmosphere at a magnification of 40 times. The liquid crystal polymer in the present invention exhibits optical anisotropy, that is, transmits light when inspected between orthogonal polarizers. If the sample is optically anisotropic, polarized light is transmitted even in a stationary state.

As the polymerizable monomer constituting the structural unit of the liquid crystal polymer in the present invention, for example, aromatic hydroxycarboxylic acid, aromatic dicarboxylic acid, aromatic diol, aromatic aminocarboxylic acid, aromatic hydroxyamine, aromatic diamines, aliphatic diols and aliphatic dicarboxylic acids. As for such a polymerizable monomer, only 1 type may be used, and 2 or more types of polymerizable monomers may be combined. Preferably, a polymerizable monomer having at least one hydroxyl group and a carboxyl group is used.

The polymerizable monomer constituting the structural unit of the liquid crystal polymer may be an oligomer formed by combining one or more of the above compounds, that is, an oligomer composed of one or more of the above compounds.

Specific examples of aromatic hydroxycarboxylic acids include 4-hydroxybenzoic acid, 3-hydroxybenzoic acid, 2-hydroxybenzoic acid, 6-hydroxy-2-naphthoic acid, 5-hydroxy-2-naphthoic acid, 7-hydroxy-2-naphthoic acid, 3-hydroxy-2-naphthoic acid, 4'-hydroxyphenyl-4-benzoic acid, 3'-hydroxyphenyl-4-benzoic acid, 4'-hydroxyphenyl-3 -ester-forming derivatives such as benzoic acid and its alkyl, alkoxy or halogen substituents and its acylates, ester derivatives and acid halides. Among these, one or more compounds selected from the group consisting of 4-hydroxybenzoic acid and 6-hydroxy-2-naphthoic acid are preferred from the viewpoint of easy control of heat resistance, mechanical strength and melting point of the obtained liquid crystal polymer.

Specific examples of aromatic dicarboxylic acids include terephthalic acid, isophthalic acid, 2,6-naphthalenedicarboxylic acid, 1,6-naphthalenedicarboxylic acid, 2,7-naphthalenedicarboxylic acid, and 4,4'. -Dicarboxybiphenyl, 3,4'-dicarboxybiphenyl and 4,4"-dicarboxyterphenyl, their alkyl, alkoxy or halogen substituents, their ester derivatives, ester-forming derivatives such as acid halides. Among these, one or more compounds selected from the group consisting of terephthalic acid, isophthalic acid and 2,6-naphthalenedicarboxylic acid are preferred from the viewpoint of effectively increasing the heat resistance of the liquid crystal polymer obtained, and terephthalic acid and 2 ,6-naphthalenedicarboxylic acid is more preferred.

Specific examples of the aromatic diol include hydroquinone, resorcinol, 2,6-dihydroxynaphthalene, 2,7-dihydroxynaphthalene, 1,6-dihydroxynaphthalene, and 3,3'-dihydroxynaphthalene. phenyl, 3,4'-dihydroxybiphenyl, 4,4'-dihydroxybiphenyl, 4,4'-dihydroxybiphenyl ether and 2,2'-dihydroxybinaphthyl, these ester-forming derivatives such as alkyl, alkoxy or halogen substituents and acylates thereof. Among these, from the viewpoint of excellent reactivity during polymerization, one or more compounds selected from the group consisting of hydroquinone, resorcinol, 4,4'-dihydroxybiphenyl and 2,6-dihydroxynaphthalene are preferred. , at least one compound selected from the group consisting of hydroquinone, 4,4'-dihydroxybiphenyl and 2,6-dihydroxynaphthalene is more preferred.

Specific examples of aromatic aminocarboxylic acids include 4-aminobenzoic acid, 3-aminobenzoic acid, 6-amino-2-naphthoic acid, alkyl, alkoxy or halogen substituted products thereof, and acylates, ester derivatives, and acid halides thereof. Ester-forming derivatives, such as these, are mentioned.

Specific examples of aromatic hydroxyamine include 4-aminophenol, N-methyl-4-aminophenol, 3-aminophenol, 3-methyl-4-aminophenol, 4-amino-1-naphthol, 4-amino- 4'-hydroxybiphenyl, 4-amino-4'-hydroxybiphenyl ether, 4-amino-4'-hydroxybiphenylmethane, 4-amino-4'-hydroxybiphenylsulfide and 2; ester-forming derivatives such as 2'-diaminobinaphthyl, alkyl, alkoxy or halogen-substituted products thereof, and acylates thereof. Among these, 4-aminophenol is preferable from the viewpoint of easily balancing the heat resistance and mechanical strength of the resulting liquid crystal polymer.

Specific examples of the aromatic diamine include 1,4-phenylenediamine, 1,3-phenylenediamine, 1,5-diaminonaphthalene, 1,8-diaminonaphthalene, alkyl, alkoxy or halogen substituents thereof, and and amide-forming derivatives such as acylates thereof.

Specific examples of the aliphatic diol include ethylene glycol, 1,4-butanediol, 1,6-hexanediol, and acylated products thereof. In addition, polymers containing aliphatic diols such as polyethylene terephthalate and polybutylene terephthalate are reacted with the above aromatic oxycarboxylic acids, aromatic dicarboxylic acids, aromatic diols and their acylated products, ester derivatives, acid halides, etc. You can do it.

Specific examples of the aliphatic dicarboxylic acid include oxalic acid, malonic acid, succinic acid, glutaric acid, adipic acid, pimelic acid, suberic acid, azelaic acid, sebacic acid, dodecanedioic acid, tetradecanedioic acid, fumaric acid, maleic acid and hexahydroterephthalic acid. Among these, oxalic acid, succinic acid, adipic acid, suberic acid, sebacic acid and dodecanedioic acid are preferable from the viewpoint of excellent reactivity during polymerization.

The polymerizable monomers forming the constituent units of the liquid crystal polymer in the present invention include dihydroxyterephthalic acid, 4-hydroxyisophthalic acid, and 5-hydroxy as other copolymerization components within a range that does not impair the object of the present invention. Ester-forming derivatives such as isophthalic acid, trimellitic acid, 1,3,5-benzene tricarboxylic acid, pyromellitic acid or their alkyl, alkoxy or halogen substituents, and their acylates, ester derivatives, acid halides, etc. may contain It is preferable that the amount of these polymerizable monomers used is 10 mol% or less with respect to all constituent units constituting the liquid crystal polymer.

In the present invention, the liquid crystal polymer may contain a thioester bond within a range not impairing the object of the present invention. Examples of the polymerizable monomer imparting such a bond include mercapto aromatic carboxylic acid, aromatic dithiol, and hydroxyaromatic thiol. It is preferable that the content of these polymerizable monomers be 10 mol% or less with respect to all constituent units constituting the liquid crystal polymer.

Among the polymers combining these repeating units, there are those that form an anisotropic molten phase and those that do not form an anisotropic molten phase depending on the structure and composition ratio of the monomers and the sequence distribution of each repeating unit in the polymer. Polymers are limited to forming an anisotropic melt phase.

As the liquid crystal polymer used in the present invention, liquid crystal polyester resins containing repeating units represented by formulas (I) and (II) are preferably used from the viewpoint of excellent fluidity and mechanical properties.

[Formula 4]

Further, as the liquid crystal polymer used in the present invention, a wholly aromatic liquid crystal polyester resin composed of repeating units represented by formulas (I) to (IV) is preferably used from the viewpoint of excellent fluidity and mechanical properties.

[Formula 5]

[In the formula, Ar ₁ and Ar ₂ each represent a divalent aromatic group.]

Here, Formulas (III) and Formulas (IV) may each contain plural types of Ar ₁ and Ar ₂ . That is, the repeating unit represented by formula (III) may be a plurality of repeating units, such as a repeating unit of one type of Ar ₁ and a repeating unit of another type of Ar ₁ . Similarly, the repeating unit represented by formula (IV) is , a repeating unit of a certain type of Ar ₂ and a repeating unit of another type of Ar ₂ , and the like may be plural repeating units. In addition, an "aromatic group" represents an aromatic group that is a 6-membered monocyclic ring or a condensed ring having 2 rings.

From the viewpoint of excellent fluidity and mechanical properties, in the repeating units represented by formulas (III) to (IV), Ar ₁ and Ar ₂ are each independently an aromatic group represented by the following formulas (1) to (4) It is more preferable that it is each 1 or more types of repeating units selected. The repeating unit represented by formula (III) is a repeating unit in which Ar ₁ is an aromatic group represented by formula (1), and in the repeating unit represented by formula (IV), Ar ₂ is represented by formula (1) and/or formula (3) ) It is particularly preferable that it is a repeating unit that is an aromatic group represented by .

[Formula 6]

Specific examples of the combination of polymerizable monomers forming the constituent units of the liquid crystal polymer used in the present invention include the following.

1) 4-hydroxybenzoic acid/6-hydroxy-2-naphthoic acid;

2) 4-hydroxybenzoic acid/terephthalic acid/4,4'-dihydroxybiphenyl;

3) 4-hydroxybenzoic acid / terephthalic acid / isophthalic acid / 4,4'-dihydroxybiphenyl;

4) 4-hydroxybenzoic acid / terephthalic acid / isophthalic acid / 4,4'-dihydroxybiphenyl / hydroquinone;

5) 4-hydroxybenzoic acid/terephthalic acid/hydroquinone;

6) 6-hydroxy-2-naphthoic acid/terephthalic acid/hydroquinone;

7) 4-hydroxybenzoic acid / 6-hydroxy-2-naphthoic acid / terephthalic acid / 4,4'-dihydroxybiphenyl;

8) 6-hydroxy-2-naphthoic acid/terephthalic acid/4,4'-dihydroxybiphenyl;

9) 4-hydroxybenzoic acid/6-hydroxy-2-naphthoic acid/terephthalic acid/hydroquinone;

10) 4-hydroxybenzoic acid / 6-hydroxy-2-naphthoic acid / terephthalic acid / hydroquinone / 4,4'-dihydroxybiphenyl;

11) 4-hydroxybenzoic acid/2,6-naphthalenedicarboxylic acid/4,4'-dihydroxybiphenyl;

12) 4-hydroxybenzoic acid/terephthalic acid/2,6-naphthalenedicarboxylic acid/hydroquinone;

13) 4-hydroxybenzoic acid/2,6-naphthalenedicarboxylic acid/hydroquinone;

14) 4-hydroxybenzoic acid/6-hydroxy-2-naphthoic acid/2,6-naphthalenedicarboxylic acid/hydroquinone;

15) 4-hydroxybenzoic acid/terephthalic acid/2,6-naphthalenedicarboxylic acid/hydroquinone/4,4'-dihydroxybiphenyl;

16) 4-hydroxybenzoic acid/terephthalic acid/4-aminophenol;

17) 6-hydroxy-2-naphthoic acid/terephthalic acid/4-aminophenol;

18) 4-hydroxybenzoic acid/6-hydroxy-2-naphthoic acid/terephthalic acid/4-aminophenol;

19) 4-hydroxybenzoic acid/terephthalic acid/4,4'-dihydroxybiphenyl/4-aminophenol;

20) 4-hydroxybenzoic acid/terephthalic acid/ethylene glycol,

21) 4-hydroxybenzoic acid/terephthalic acid/4,4'-dihydroxybiphenyl/ethylene glycol,

22) 4-hydroxybenzoic acid / 6-hydroxy-2-naphthoic acid / terephthalic acid / ethylene glycol,

23) 4-hydroxybenzoic acid / 6-hydroxy-2-naphthoic acid / terephthalic acid / 4,4'-dihydroxybiphenyl / ethylene glycol,

24) 4-hydroxybenzoic acid/terephthalic acid/2,6-naphthalenedicarboxylic acid/4,4'-dihydroxybiphenyl.

Among these, liquid crystal polymers composed of structural units derived from the polymerizable monomers of 1), 9), 10), and 14) are preferred, and structural units derived from the polymerizable monomers of 9), 10), and 14). A liquid crystal polymer composed of is more preferable, and a liquid crystal polymer composed of constituent units derived from polymerizable monomers of 9) is particularly preferable in view of reducing generation of particles and warping in a molded article.

The above liquid crystal polymers may be used alone or as a mixture of two or more liquid crystal polymers.

One of the preferable aspects of the liquid crystal polymer used in the present invention is a wholly aromatic liquid crystal polyester resin composed of repeating units represented by the following formulas (A) to (D).

[Formula 7]

[In the formula, p, q, r and s represent the composition ratio (mol%) of each repeating unit in the liquid crystal polyester resin, and satisfy the following conditions:

0.1 ≤ q/(p + q) ≤ 0.9;

8 ≤ q ≤ 34;

10 ≤ r ≤ 25, and

10 ≤ s ≤ 25]

Hereinafter, a method for producing the liquid crystal polymer used in the present invention will be described.

The method for producing the liquid crystal polymer used in the present invention is not particularly limited, and a known polycondensation method for forming an ester bond or an amide bond with a polymerizable monomer, such as a melt acidosis method or a slurry polymerization method, is provided. A liquid crystal polymer can be obtained.

The melt acidosis method is a preferred method for producing the liquid crystal polymer used in the liquid crystal polymer composition of the present invention. In this method, a polymerizable monomer is first heated to form a molten solution of the reactants, and then the polycondensation reaction is continued to obtain a molten polymer. Further, a vacuum may be applied to facilitate the removal of volatiles (for example, acetic acid, water, etc.) produced as a by-product in the final stage of condensation.

The slurry polymerization method is a method in which polymerizable monomers are reacted in the presence of a heat exchange fluid, and a solid product is obtained in a suspended state in a heat exchange medium.

In either of the melt acidolescence method and the slurry polymerization method, the polymerizable monomer used when producing the liquid crystal polymer is a modified form obtained by acylating a hydroxyl group and/or an amino group at room temperature (lower acyl group) , that is, it may be used for the reaction as a lower acylate.

The lower acyl group preferably has 2 to 5 carbon atoms, and more preferably has 2 or 3 carbon atoms. In a preferred embodiment of the present invention, an acetylate of the polymerizable monomer is subjected to the reaction.

As the lower acylate of the polymerizable monomer, one previously synthesized by acylating separately may be used, or an acylating agent such as acetic anhydride may be added to the polymerizable monomer during production of the liquid crystal polymer to be generated in the reaction system.

In either case of the melt acidosis method or the slurry polymerization method, the polycondensation reaction is preferably carried out at a temperature of usually 150 to 400°C, preferably 250 to 370°C, under normal pressure and/or reduced pressure, and it is necessary Depending on the catalyst, a catalyst may be used.

Specific examples of the catalyst include, for example, organic tin compounds (dialkyl tin oxide such as dibutyl tin oxide, diaryl tin oxide, etc.), titanium dioxide, antimony trioxide, organic titanium compounds (alkoxytitanium silicate, titanium alkoxide, etc.) ), alkali and alkaline earth metal salts of carboxylic acids (such as potassium acetate and sodium acetate), Lewis acids (such as BF ₃ ), gaseous acid catalysts such as hydrogen halide (such as HCl), and the like.

When a catalyst is used, the amount of the catalyst is preferably 1 to 1000 ppm, more preferably 2 to 100 ppm, based on the total amount of the polymerizable monomers.

The liquid crystal polymer obtained by such a polycondensation reaction is usually taken out of the polymerization reactor in a molten state, then processed into pellets, flakes, or powder, and melt-kneaded with other components.

Pellets, flakes, or powdery liquid crystal polyesters may be subjected to heat treatment in a substantially solid state under reduced pressure, under vacuum, or in an atmosphere such as nitrogen or helium, which is an inert gas, for the purpose of increasing molecular weight and improving heat resistance. do.

The liquid crystal polymer composition of the present invention contains, in addition to the liquid crystal polymer, titanium oxide and mica.

The crystal structure of titanium oxide used in the present invention is not particularly limited, but one or more types selected from the group consisting of rutile type, anatase type and brucite type can be used. Among them, rutile type and anatase type are preferable from the viewpoint of being excellent in the effect of reducing generation of particles during ultrasonic cleaning. Moreover, it may be doped with other metal oxides, such as magnesium and calcium, in order to improve dispersion to resin.

The titanium oxide used in the present invention may be used by treating the surface thereof with a known coupling agent (for example, a silane-based coupling agent, titanate-based coupling agent, aluminum-based coupling agent, etc.) or other surface treating agent.

The average particle diameter of titanium oxide is preferably 0.5 μm or less, more preferably 0.03 to 0.48 μm, still more preferably 0.05 to 0.26 μm, particularly preferably 0.07 to 0.25 μm, and most preferably 0.08 to 0.20 μm. .

When the average particle diameter of titanium oxide exceeds 0.5 µm, it tends to be difficult to reduce generation of particles.

In this specification and claims, the "average particle diameter" means the volume-based cumulative 50% diameter of particles determined by the laser diffraction scattering method. That is, the particle size distribution is measured by the laser diffraction scattering method, and a cumulative curve is obtained with the total volume of the group of particles as 100%.

The content of titanium oxide in the liquid crystal polymer composition of the present invention is 1 to 50 parts by mass, preferably 2 to 40 parts by mass, more preferably 3 to 30 parts by mass, and 5 to 25 parts by mass, based on 100 parts by mass of the liquid crystal polymer. Addition is particularly preferred. When the content of titanium oxide is less than 1 part by mass, the effect of suppressing particle generation is insufficient, and when it exceeds 50 parts by mass, fluidity becomes insufficient and wear of the cylinder and mold of the molding machine increases.

The mica used in the present invention is a pulverized material of a silicate mineral that has hydrous aluminum silicate potassium as a main component and may contain magnesium, sodium, iron, etc. in addition to aluminum and potassium, and is composed of muscovite, phlogopite, biotite, artificial mica, etc. can be heard Among these, muscovite mica is preferable in terms of good color and easy availability.

The mica used in the present invention may be surface-treated with a silane coupling agent or the like, or may be granular by being granulated with a binder.

The mica used in the present invention preferably has an average particle diameter of 5 to 100 µm, more preferably 10 to 80 µm, and particularly preferably 20 to 60 µm. The average particle diameter of mica is the volume-based cumulative 50% diameter of the particles determined by the laser diffraction scattering method.

The content of mica in the liquid crystal polymer composition of the present invention is 1 to 50 parts by mass, preferably 2 to 40 parts by mass, more preferably 3 to 30 parts by mass, and 5 to 25 parts by mass with respect to 100 parts by mass of the liquid crystal polymer. particularly preferred. If the content of mica is less than 1 part by mass, the effect of suppressing particle generation is insufficient, and if it is more than 50 parts by mass, fluidity becomes insufficient.

Further, the content ratio of titanium oxide and mica (parts by mass of titanium oxide/part by mass of mica) in the liquid crystal polymer composition of the present invention is 0.1 to 10, preferably 0.2 to 5, more preferably 0.3 to 3.5, more preferably from 0.4 to 2.5, particularly preferably from 0.5 to 2.

When the content ratio of titanium oxide and mica is less than 0.1, the effect of suppressing particle generation is not obtained, and when the content ratio of titanium oxide and mica exceeds 10, the effect of improving warpage cannot be obtained.

The liquid crystal polymer composition of the present invention may further contain graphite for the purpose of further suppressing the occurrence of warpage in molded articles. The graphite used in the present invention may be natural graphite, artificial graphite, or a combination of two or more thereof. Graphite preferably has a high fixed carbon content, low ash content such as silicon oxide, and high crystallinity.

The average particle diameter of graphite is usually 5 to 100 µm, preferably 5 to 80 µm, and more preferably 5 to 60 µm. The average particle diameter of graphite is the volume-based cumulative 50% diameter of the particles determined by the laser diffraction scattering method.

When graphite is contained, the content thereof is 0.1 to 20 parts by mass, preferably 1 to 17 parts by mass, more preferably 3 to 15 parts by mass, particularly preferably 5 to 10 parts by mass, based on 100 parts by mass of the liquid crystal polymer. is the mass part. When the content of graphite is less than 0.1 part by mass, it is difficult to obtain an additional warpage improvement effect, and when the content of graphite exceeds 20 parts by mass, fluidity tends to be insufficient.

The liquid crystal polymer composition of the present invention may further contain a higher fatty acid ester and/or a higher fatty acid metal salt.

The content of the higher fatty acid ester and/or the higher fatty acid metal salt is 0.01 to 1.3 parts by mass, preferably 0.03 to 1.2 parts by mass, and more preferably 0.05 to 1.0 parts by mass. When the content of the higher fatty acid ester is equal to or greater than the lower limit above, swelling is further suppressed, and when the content of the higher fatty acid ester is equal to or less than the upper limit value, blisters are less likely to occur. When the content of the higher fatty acid ester and/or the higher fatty acid metal salt is less than 0.01 parts by mass, swelling tends to occur, and when the content exceeds 1.3 parts by mass, blisters tend to occur.

The higher fatty acid used as a raw material for the higher fatty acid ester and/or the higher fatty acid metal salt used in the present invention preferably has 10 or more carbon atoms. Examples of such higher fatty acids include capric acid, lauric acid, myristic acid, palmitic acid, stearic acid, arachic acid, behenic acid, lignoceric acid, and montanic acid. Of these, stearic acid and montanic acid are preferred.

As an alcohol used as a raw material of ester, stearyl alcohol, behenyl alcohol, glycerin, sorbitan, propylene glycol, pentaerythritol, polyoxyethylene bisphenol A, etc. are mentioned.

Further, examples of the metal constituting the metal salt include alkali metals such as lithium, sodium, and potassium, alkaline earth metals such as magnesium, calcium, and barium, zinc, and the like, and alkaline earth metals are particularly preferably used. Specific examples of higher fatty acid metal salts include calcium stearate, barium stearate, zinc stearate, magnesium stearate, sodium montanate, calcium montanate, magnesium montanate, potassium montanate, lithium montanate, zinc montanate, and montanic acid. Barium, aluminum montanate, calcium palmitate, magnesium palmitate, barium palmitate, etc. are mentioned. Among these, calcium stearate and calcium montanate are preferably used from the viewpoint of cost and maintaining physical properties of molded products.

The higher fatty acid ester and/or higher fatty acid metal salt used in the present invention is preferably in the form of powder or particles to facilitate mixing with the liquid crystal polyester resin composition.

The liquid crystal polymer composition of the present invention may further contain other resin components within a range not impairing the object of the present invention. Examples of other resin components include thermoplastic resins such as polyamide, polyester, polyacetal, polyphenylene ether and modified products thereof, polysulfone, polyethersulfone, polyetherimide and polyamideimide, and phenolic resins. , thermosetting resins such as epoxy resins and polyimide resins.

Other resin components can be contained individually or in combination of 2 or more types. The content of other resin components is not particularly limited, and may be appropriately determined according to the use or purpose of the liquid crystal polymer composition. Typically, the total content of other resins relative to 100 parts by mass of the liquid crystal polymer is added within a range of preferably 0.1 to 100 parts by mass, more preferably 0.2 to 80 parts by mass.

The liquid crystal polymer composition of the present invention may contain other fibrous, plate-like, or granular inorganic fillers or organic fillers within a range that does not impair the effects of the present invention.

When the liquid crystal polymer composition of the present invention contains other fibrous, plate-like, or granular inorganic fillers or organic fillers, the content thereof is preferably 30 parts by mass or less, more preferably 30 parts by mass or less, based on 100 parts by mass of liquid crystalline polyester. It is 20 parts by mass or less, more preferably 10 parts by mass or less. When the content of these other fillers exceeds the above upper limit, molding processability tends to decrease or thermal stability deteriorates.

Other fibrous fillers include, for example, milled glass, silica alumina fibers, alumina fibers, carbon fibers, aramid fibers, polyarylate fibers, polybenzimidazole fibers, potassium titanate whiskers, aluminum borate whiskers, etc., These may be used alone or in combination of two or more.

Other platy fillers include, for example, kaolin, clay, vermiculite, feldspar powder, acid clay, pyrophyllite clay, sericite, silimonite, bentonite, glass flakes, slate powder, silicates such as silane, carbonic acid Calcium, whiting, barium carbonate, magnesium carbonate, carbonates such as dolomite, barite powder, precipitated calcium sulfate, calcined gypsum, sulfates such as barium sulfate, hydroxides such as hydrated alumina, alumina, antimony oxide, magnesia, zinc oxide, silica, silica sand, oxides such as quartz, white carbon, and diatomaceous earth, sulfides such as molybdenum disulfide, and plate-shaped wollastonite, and the like, and these may be used alone or in combination of two or more.

Examples of other granular fillers include calcium carbonate, glass beads, barium sulfate, and the like, and these may be used alone or in combination of two or more.

Further, the liquid crystal polymer composition of the present invention may contain additives other than those described above within a range that does not impair the effects of the present invention.

Other additives include, for example, mold release improving agents such as polysiloxane and fluororesin, coloring agents such as dyes, pigments, carbon black, flame retardants, antistatic agents, surfactants, phosphorus antioxidants as antioxidants, phenolic antioxidants, and sulfur-based oxidation anti-weathering agents, heat stabilizers, neutralizers, and the like. These additives may be used independently or may use 2 or more types together.

The content of these other additives is preferably from 0.1 to 10 parts by mass, more preferably from 0.5 to 5 parts by mass, based on 100 parts by mass of the liquid crystal polymer. When the content of these other additives exceeds the above upper limit, molding processability tends to decrease or thermal stability deteriorates.

Liquid crystal polymer, titanium oxide and mica, if desired, graphite, higher fatty acid esters or higher fatty acid metal salts, other resin components, other fibrous, plate-like, granular inorganic fillers or organic fillers, other additives, etc. are blended in a predetermined composition, The liquid crystal polymer composition of the present invention can be obtained by melt-kneading using a Banbury mixer, kneader, single screw or twin screw extruder, or the like.

The liquid crystal polymer composition of the present invention thus obtained can be molded or processed by a known molding method using an injection molding machine, an extruder or the like to obtain a desired molded article.

A molded article made of a liquid crystal polymer composition is usually easily peeled off on the surface of the molded article, and when ultrasonically cleaned, the surface is peeled off and raised fibrillation is likely to occur. Hereinafter referred to as particles) are likely to occur.

Since the generation of particles is suppressed according to the liquid crystal polymer composition of the present invention, the molded article does not become a foreign substance during assembly and use in an optical member such as a camera module, and good optical properties can be obtained.

In addition, the liquid crystal polymer composition of the present invention exhibits a very small amount of warpage. The amount of warpage can be measured by the method for measuring the amount of warpage described below.

<Definition and measurement method of warpage amount>

In this specification, "amount of warpage" refers to a planar test piece (thickness: 0.5 mm, length and width) having a slit-like step in the central portion using an injection molding machine (for example, NEX15-1E manufactured by Nissei Resin Co., Ltd.) under the conditions described below. 17 mm in length, 3 mm in width and 0.25 mm in thickness of the central slit-shaped step), and using a three-dimensional measuring machine (for example, Keyence Oneshot 3D VR-3000), the test piece thickness (0.5 mm) from the maximum bending height ) is the value minus

In this way, the molded article composed of the liquid crystal polymer composition of the present invention reduces the generation of particles when ultrasonically cleaned and suppresses the occurrence of warpage in the molded article, so connectors, switches, relays, capacitors, coils, transformers , camera modules, electronic components such as antennas are preferably used. Especially useful for camera modules.

Example

Hereinafter, the present invention will be described by examples, but the present invention is not limited to the following examples at all. In addition, the melt viscosity, tensile strength, bending strength, the number of particles generated, and the amount of warpage in Examples were measured by the methods described below.

<Melt viscosity>

The crystal melting temperature ^of the sample (Tm ) + 20 ° C. The melt viscosity was measured respectively.

<tensile strength>

Using an injection molding machine (UH1000-110 manufactured by Nissei Resin Industry Co., Ltd.), injection molding was performed at a cylinder temperature of 350°C and a mold temperature of 70°C to prepare ASTM No. 4 dumbbell test pieces. It was measured based on ASTM D638 using INSTRON5567 (a universal tester manufactured by Instron Japan Co., Ltd.).

<bending strength>

It measured based on ASTM D790 using the same test piece as the test piece used for the measurement of deflection temperature under load.

<Number of Particles>

A test piece identical to the test piece used for the load deflection temperature measurement was placed in a cylindrical glass container having an outer diameter of 50 mm, an inner diameter of 45 mm, and a height of 100 mm equipped with 50 mL of pure water so that the gate portion was not submerged in water, and then the cylinder The glass container was installed in a 140 mm long, 240 mm wide, 100 mm deep ultrasonic cleaning tank (US-102 manufactured by SND Co., Ltd.) equipped with 1000 mL of water. After performing ultrasonic cleaning for 10 minutes at an output of 38 kHz and 100 W, the number of particles having a particle diameter of 2 μm or more contained in 1 mL of pure water [exfoliated matter (particles) exfoliated from the test piece] was measured by a particle counter (spec. The average value measured three times using LiQuilaz-05) manufactured by Tris was taken as the measurement result, and less than 500 was indicated as “○”, 500 or more and less than 1000 as “Δ”, and 1000 or more as “×”. .

<Amount of Warpage>

Using an injection molding machine (NEX15-1E manufactured by Nissei Resin Co., Ltd.), under the conditions described in Table 1, a flat test piece having a slit-like step in the center portion shown in FIG. A step width of 3 mm and a thickness of 0.25 mm) was molded. After allowing this test piece to stand still for 24 hours under conditions of 23°C and 50% relative humidity, the thickness of the test piece (0.5 mm) was measured from the maximum bending height using a three-dimensional measuring device (Oneshot 3D VR-3000 manufactured by Keyence Corporation). The value subtracted was taken as the amount of warpage.

[Synthesis Example 1 (Synthesis of Liquid Crystal Polymer)]

To a reaction vessel equipped with a stirrer equipped with a torque meter and an outflow pipe, 431 g (48 mol%) of parahydroxybenzoic acid, 196 g (16 mol%) of 6-hydroxy-2-naphthoic acid, and 194 g of terephthalic acid ( 18 mol%) and 129 g (18 mol%) of hydroquinone were injected so that the total amount was 6.5 mol, and further 1.03 times mol of acetic anhydride was charged with respect to the amount of hydroxyl groups (mol) of all monomers, followed by deacetic acid polymerization under the following conditions was carried out.

The temperature was raised from room temperature to 150°C for 1 hour under a nitrogen gas atmosphere, and maintained at the same temperature for 30 minutes. Then, after raising the temperature to 350°C over 7 hours while distilling off acetic acid produced as a by-product, the pressure was reduced to 5 mmHg over 80 minutes. When the predetermined torque was reached, the polymerization reaction was terminated, the contents of the reaction vessel were taken out, and liquid crystal polymer pellets were obtained by a grinder. The distillate amount of acetic acid at the time of polymerization was almost the theoretical value.

The fillers used in the following Examples and Comparative Examples are shown.

Titanium oxide 1: "A-100" manufactured by Ishihara Sangyo Co., Ltd. (average particle diameter: 0.15 µm)

Titanium oxide 2: "TIO20PB" manufactured by Kojundo Chemical Research Institute Co., Ltd. (average particle diameter: 0.5 µm)

Mica: "AB-25S" manufactured by Yamaguchi Mica

Talc: "RL119" manufactured by Fuji Talc

Graphite: "PC-30" manufactured by Ito Graphite

Higher fatty acid ester: Licowax E flakes powder manufactured by Clariant Japan

Examples 1 to 7 and Comparative Examples 1 to 5

LCP, titanium oxide, mica, talc, graphite and higher fatty acid esters synthesized in Synthesis Example 1 were blended so as to have the contents (parts by mass) shown in Table 1, and a twin-screw extruder (Nippon Steel Co., Ltd. TEX-30) was used. melt-kneading was performed at 350°C to obtain pellets of the liquid crystal polymer composition. Melt viscosity, tensile strength, bending strength, number of particles generated, and warpage amount were measured by the above methods. A result is shown in Table 1.

As shown in Table 1, all of the liquid crystal polymer compositions of Examples 1 to 7 had less than 1000 particles having a particle diameter of 2 μm or more and had a small amount of warpage.

On the other hand, the liquid crystal polymer compositions of Comparative Examples 1 to 5 gave undesirable results in terms of at least one of particle generation or warpage.

Claims (9)

A liquid crystal polymer containing 100 parts by mass of a liquid crystal polymer, 1 to 50 parts by mass of titanium oxide, and 1 to 50 parts by mass of mica, and the ratio of the content of titanium oxide (parts by mass) to the content of mica (parts by mass) is 0.1 to 10. composition. According to claim 1,
The liquid crystal polymer composition, wherein the titanium oxide has an average particle diameter of 0.5 µm or less. According to claim 1 or 2,
The liquid crystal polymer is represented by the formulas (I) and (II)

A liquid crystal polymer composition that is a liquid crystal polyester resin containing a repeating unit represented by . According to any one of claims 1 to 3,
The liquid crystal polymer has formulas (I) to (IV)

[In the formula, Ar ₁ and Ar ₂ each represent a divalent aromatic group]
A liquid crystal polymer composition which is a wholly aromatic liquid crystal polyester resin composed of repeating units represented by According to claim 4,
In the repeating units represented by formulas (III) to (IV), Ar ₁ and Ar ₂ are independently of each other, and formulas (1) to (4)

A liquid crystal polymer composition, each of which is one or more repeating units selected from aromatic groups represented by . According to claim 4 or 5,
The repeating unit represented by formula (III) is a repeating unit in which Ar ₁ is an aromatic group represented by formula (1), and the repeating unit represented by formula (IV) is a repeating unit in which Ar ₂ is an aromatic group represented by formula (1), and/ Or a liquid crystal polymer composition that is a repeating unit that is an aromatic group represented by Formula (3). According to any one of claims 1 to 6,
A liquid crystal polymer composition, further comprising graphite. A molded article composed of the liquid crystal polymer composition according to any one of claims 1 to 7. According to claim 8,
The molded product is a molded product that is a component constituting one type selected from the group consisting of connectors, switches, relays, capacitors, coils, transformers, camera modules, and antennas.

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