Liquid crystal polymer composition

Abstract

To provide a liquid crystal polymer composition that suppresses the generation of particles in ultrasound cleaning of a molding, and also suppresses the occurrence of a warp in the molding.SOLUTION: A liquid crystal polymer composition contains liquid crystal polymer 100 pts.mass, titanium oxide 1-50 pts.mass and mica 1-50 pts.mass. The ratio of the titanium oxide content (mass part) to the mica content (mass part) is 0.1-10.SELECTED DRAWING: None

Description

Technical Field

[0001] The present invention relates to a liquid crystal polymer composition in which particle generation during ultrasonic cleaning is reduced and warping of a molded product is suppressed.

Background Art

[0002] Liquid crystal polymers are used in parts in a wide variety of fields because they are excellent in mechanical properties, moldability, chemical resistance, gas barrier properties, moisture resistance, electrical properties, etc. In particular, because of their excellent heat resistance and thin-wall moldability, their use in electronic parts such as precision equipment is expanding.

[0003] On the other hand, it is known that in molded products made of liquid crystal polymer, the resin surface peels off and fibrillates (hereinafter referred to as "fibrillation") occurs due to ultrasonic cleaning or sliding with other members. In the case of precision equipment, especially optical equipment such as lenses, even a small amount of dust or dirt can affect the performance of the equipment. For example, in parts used in optical equipment such as camera modules, when small dust, oil, dirt, etc. adhere to the lens, it causes a significant deterioration in the optical characteristics of the camera module.

[0004] For the purpose of preventing such a deterioration in optical characteristics, parts constituting a camera module (hereinafter also referred to as "parts for camera modules"), such as a lens barrel part, a mount holder part, a frame of a CMOS (image sensor), a shutter, and a shutter bobbin part, are usually ultrasonically cleaned before assembly to remove small dust, dirt, etc. adhering to the surface.

[0005] However, molded products made of liquid crystal polymer compositions have a surface that is easily peeled off, and fibrillation in which the surface peels off and becomes hairy easily occurs during ultrasonic cleaning. And small powders and dusts (hereinafter referred to as particles) made of the resin composition are likely to be generated from the fibrillated part. And even if the generated particles are extremely minute, they become foreign matters during camera module assembly and during camera use, and there has been a problem of significantly deteriorating the optical characteristics of the camera module.

[0006] As a liquid crystal polymer composition with reduced particle generation, a resin composition containing a specific filler (such as talc, glass fiber, carbon black, etc.) or an olefin copolymer in a liquid crystal polymer has been proposed (Patent Documents 1 to 6).

Prior Art Documents

Patent Documents

[0007]

Patent Document 1

Patent Document 2

Patent Document 3

Patent Document 4

Patent Document 5

Patent Document 6

Summary of the Invention

Problems to be Solved by the Invention

[0008] However, for these, the wettability between the inorganic filler and the liquid crystal polymer was poor, and the effect of suppressing particle generation during ultrasonic cleaning was insufficient. In addition, depending on the filler to be contained, there was a problem that the molded product warped.

[0009] Therefore, 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 warping in the molded product is small. 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 a molded product and suppressing the occurrence of warping in the molded product.

Means for Solving the Problems

[0010] In view of the above problems, the inventors of the present invention have conducted intensive studies. As a result, they have found that by containing titanium oxide and mica in a specific ratio in a liquid crystal polymer, when a molded article of the liquid crystal polymer composition is ultrasonically cleaned, the generation of particles is reduced and the warpage is improved. Based on this finding, the present invention has been completed.

[0011] That is, the present invention includes the following preferred embodiments. 〔1〕A liquid crystal polymer composition 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, 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. 〔2〕The liquid crystal polymer composition according to 〔1〕, wherein the average particle diameter of the titanium oxide is 0.5 μm or less. 〔3〕The liquid crystal polymer is a liquid crystal polyester resin containing repeating units represented by formula (I) and formula (II)

Chemical formula

Chemical formula

Chemical formula

Advantages of the Invention

[0012] The liquid crystal polymer composition of the present invention can reduce the generation of particles when the molded article is ultrasonically cleaned, and suppress the generation of warpage in the molded article. Therefore, it can be suitably used as a resin for molding parts that require ultrasonic cleaning, particularly electronic parts.

Brief Description of the Drawings

[0013]

Figure 1

Embodiments for Carrying Out the Invention

[0014] 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 polyester amide that forms an anisotropic molten phase, and is not particularly limited as long as it is what is called a thermotropic liquid crystal polyester or thermotropic liquid crystal polyester amide in the technical field.

[0015] The properties of the anisotropic molten phase can be confirmed by a conventional polarization inspection method using crossed polarizers. More specifically, the confirmation of the anisotropic molten phase can be carried out by using a Leitz polarizing microscope and observing a sample placed on a Leitz hot stage at a magnification of 40 times under a nitrogen atmosphere. The liquid crystal polymer in the present invention exhibits optical anisotropy, that is, it transmits light when inspected between crossed polarizers. When the sample is optically anisotropic, the polarized light is transmitted even in a stationary state.

[0016] Examples of the polymerizable monomer constituting the structural unit of the liquid crystal polymer in the present invention include aromatic hydroxycarboxylic acids, aromatic dicarboxylic acids, aromatic diols, aromatic aminocarboxylic acids, aromatic hydroxyamines, aromatic diamines, aliphatic diols, and aliphatic dicarboxylic acids. Such a polymerizable monomer may be used alone or in combination of two or more polymerizable monomers. Preferably, a polymerizable monomer having at least one hydroxy group and one carboxyl group is used.

[0017] The polymerizable monomer constituting the structural unit of the liquid crystal polymer may be an oligomer formed by bonding one or more of the above compounds, that is, an oligomer composed of one or more of the above compounds.

[0018] Specific examples of the aromatic hydroxycarboxylic acid 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-benzoic acid, and their alkyl, alkoxy or halogen substituents, and ester-forming derivatives such as their acylates, ester derivatives, acid halides, etc. Among these, from the viewpoint of easily adjusting the heat resistance, mechanical strength and melting point of the obtained liquid crystal polymer, one or more compounds selected from the group consisting of 4-hydroxybenzoic acid and 6-hydroxy-2-naphthoic acid are preferable.

[0019] Specific examples of the aromatic dicarboxylic acid include terephthalic acid, isophthalic acid, 2,6-naphthalenedicarboxylic acid, 1,6-naphthalenedicarboxylic acid, 2,7-naphthalenedicarboxylic acid, 4,4'-dicarboxybiphenyl, 3,4'-dicarboxybiphenyl, and 4,4''-dicarboxytriphenyl, their alkyl, alkoxy or halogen substituents, and ester-forming derivatives such as their ester derivatives and acid halides. Among these, from the viewpoint of effectively enhancing the heat resistance of the obtained liquid crystal polymer, one or more compounds selected from the group consisting of terephthalic acid, isophthalic acid, and 2,6-naphthalenedicarboxylic acid are preferred, and terephthalic acid and 2,6-naphthalenedicarboxylic acid are more preferred.

[0020] Specific examples of the aromatic diol include hydroquinone, resorcinol, 2,6-dihydroxynaphthalene, 2,7-dihydroxynaphthalene, 1,6-dihydroxynaphthalene, 3,3'-dihydroxybiphenyl, 3,4'-dihydroxybiphenyl, 4,4'-dihydroxybiphenyl, 4,4'-dihydroxybiphenyl ether, and 2,2'-dihydroxybinaphthyl, their alkyl, alkoxy or halogen substituents, and ester-forming derivatives such as their acylates. 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, and one or more compounds selected from the group consisting of hydroquinone, 4,4'-dihydroxybiphenyl, and 2,6-dihydroxynaphthalene are more preferred.

[0021] Specific examples of the aromatic aminocarboxylic acid include 4-aminobenzoic acid, 3-aminobenzoic acid, 6-amino-2-naphthoic acid, their alkyl, alkoxy or halogen substituents, and ester-forming derivatives such as their acylates, ester derivatives, and acid halides.

[0022] Specific examples of aromatic hydroxyamines 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'-hydroxybiphenyl methane, 4-amino-4'-hydroxybiphenyl sulfide, and 2,2'-diaminobinaphthyl, their alkyl, alkoxy, or halogen substituents, and ester-forming derivatives such as their acylates. Among these, 4-aminophenol is preferred from the viewpoint of easily achieving a balance between the heat resistance and mechanical strength of the resulting liquid crystal polymer.

[0023] Specific examples of aromatic diamines include 1,4-phenylenediamine, 1,3-phenylenediamine, 1,5-diaminonaphthalene, 1,8-diaminonaphthalene, their alkyl, alkoxy, or halogen substituents, and amide-forming derivatives such as their acylates.

[0024] Specific examples of aliphatic diols include ethylene glycol, 1,4-butanediol, 1,6-hexanediol, and their acylates. Further, polymers containing aliphatic diols such as polyethylene terephthalate and polybutylene terephthalate may be reacted with the above-mentioned aromatic oxycarboxylic acids, aromatic dicarboxylic acids, aromatic diols, and their acylates, ester derivatives, acid halides, etc.

[0025] Specific examples of aliphatic dicarboxylic acids 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 preferred from the viewpoint of excellent reactivity during polymerization.

[0026] The polymerizable monomers that form the constitutional units of the liquid crystal polymer in the present invention may, within a range not impairing the object of the present invention, contain, as other copolymerization components, dihydroxyterephthalic acid, 4-hydroxyisophthalic acid, 5-hydroxyisophthalic acid, trimellitic acid, 1,3,5-benzenetricarboxylic acid, pyromellitic acid or their alkyl, alkoxy or halogen substituents, and ester-forming derivatives such as their acylates, ester derivatives, acid halides, etc. The amount of these polymerizable monomers used is preferably such that it is 10 mol% or less based on all the constitutional units constituting the liquid crystal polymer.

[0027] 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 monomers that provide such a bond include mercaptoaromatic carboxylic acids, and aromatic dithiols and hydroxyaromatic thiols. The content of these polymerizable monomers is preferably such that it is 10 mol% or less based on all the constitutional units constituting the liquid crystal polymer.

[0028] Among the polymers combined with these repeating units, there are those that form a mesomorphic molten phase and those that do not form a mesomorphic molten phase depending on the monomer constitution, composition ratio, and sequence distribution of each repeating unit in the polymer. However, the liquid crystal polymer used in the present invention is limited to those that form a mesomorphic molten phase.

[0029] As the liquid crystal polymer used in the present invention, a liquid crystal polyester resin containing the repeating units represented by formula (I) and formula (II) is preferably used in terms of excellent fluidity and mechanical properties.

Chemical formula

[0030] Furthermore, as the liquid crystal polymer used in the present invention, an all-aromatic liquid crystal polyester resin composed of the repeating units represented by formula (I) to (IV) is preferably used in terms of excellent fluidity and mechanical properties. [Chemical formula] [In the formula, Ar1 and Ar2 each represent a divalent aromatic group.]

[0031] Here, Formula (III) and Formula (IV) may each contain a plurality of types of Ar1 and Ar2. That is, the repeating unit represented by Formula (III) may be a plurality of repeating units such as a repeating unit of a certain type of Ar1 and a repeating unit of another type of Ar1. Similarly, the repeating unit represented by Formula (IV) may be a plurality of repeating units such as a repeating unit of a certain type of Ar2 and a repeating unit of another type of Ar2. Further, the "aromatic group" refers to an aromatic group that is a 6-membered monocyclic ring or a condensed ring having 2 rings.

[0032] In terms of excellent fluidity and mechanical properties, the repeating units represented by Formulas (III) to (IV) are more preferably each one or more repeating units in which Ar1 and Ar2 are each independently selected from the aromatic groups represented by the following Formulas (1) to (4). The repeating unit represented by Formula (III) is a repeating unit in which Ar1 is the aromatic group represented by Formula (1), and the repeating unit represented by Formula (IV) is particularly preferably a repeating unit in which Ar2 is the aromatic group represented by Formula (1) and / or Formula (3). [Chemical formula]

[0033] Specific examples of the combination of polymerizable monomers that form the constitutional units of the liquid crystal polymer used in the present invention include, for example, 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.

[0034] Among these, liquid crystal polymers composed of structural units derived from the polymerizable monomers of 1), 9), 10), and 14) are preferred, liquid crystal polymers composed of structural units derived from the polymerizable monomers of 9), 10), and 14) are more preferred, and since the generation of particles and the warpage in the molded article are further reduced, the liquid crystal polymer composed of structural units derived from the polymerizable monomer of 9) is particularly preferred.

[0035] The above liquid crystal polymer may be used alone or as a mixture of two or more liquid crystal polymers.

[0036] One of the preferred embodiments of the liquid crystal polymer used in the present invention is an all-aromatic liquid crystal polyester resin composed of repeating units represented by the following formulas (A) to (D).

[0037]

Chemical formula

[0038] Hereinafter, the method for producing the liquid crystal polymer used in the present invention will be described.

[0039] There is no particular limitation on the method for producing the liquid crystal polymer used in the present invention. The polymerizable monomer can be subjected to a known polycondensation method for forming an ester bond or an amide bond, such as a melt acidolysis method, a slurry polymerization method, etc., to obtain a liquid crystal polymer.

[0040] The melt acidolysis 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, first, the polymerizable monomer is heated to form a molten solution of the reactants, and then the polycondensation reaction is continued to obtain a molten polymer. In addition, a vacuum may be applied to facilitate the removal of volatile by-products (such as acetic acid, water, etc.) generated in the final stage of condensation.

[0041] The slurry polymerization method is a method in which a polymerizable monomer is reacted in the presence of a heat exchange fluid, and the solid product is obtained in a state suspended in the heat exchange medium.

[0042] In both the case of the melt acidolysis method and the slurry polymerization method, the polymerizable monomer used in producing the liquid crystal polymer can also be subjected to the reaction as a modified form (lower acyl group) in which the hydroxyl group and / or amino group is acylated at normal temperature, that is, as a lower acyl compound.

[0043] The lower acyl group preferably has 2 to 5 carbon atoms, and more preferably 2 or 3 carbon atoms. In a preferred embodiment of the present invention, the acetylated product of the polymerizable monomer is subjected to the reaction.

[0044] As the lower acyl compound of the polymerizable monomer, those separately acylated and pre-synthesized may be used, or an acylating agent such as acetic anhydride may be added to the polymerizable monomer during the production of the liquid crystal polymer to generate it in the reaction system.

[0045] In either the melt acidolysis method or the slurry polymerization method, the polycondensation reaction is usually carried out at a temperature of 150 to 400 °C, preferably 250 to 370 °C, under normal pressure and / or reduced pressure, and a catalyst may be used if necessary.

[0046] Specific examples of the catalyst include, for example, organotin compounds (dialkyltin oxides such as dibutyltin oxide, diaryltin oxides, etc.), titanium dioxide, antimony trioxide, organic titanium compounds (alkoxytitanium silicates, titanium alkoxides, etc.), alkali and alkaline earth metal salts of carboxylic acids (potassium acetate, sodium acetate, etc.), Lewis acids (such as BF3), and gaseous acid catalysts such as hydrogen halides (such as HCl).

[0047] When using a catalyst, 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 monomer.

[0048] The liquid crystal polymer obtained by such a polycondensation reaction is usually withdrawn from the polymerization reaction tank in a molten state and then processed into pellets, flakes, or powder, and subjected to melt kneading with other components.

[0049] The pellet-shaped, flake-shaped, or powder-shaped liquid crystal polyester may be heat-treated in a substantially solid state under reduced pressure, under vacuum, or in an atmosphere of an inert gas such as nitrogen or helium for the purpose of increasing the molecular weight and improving the heat resistance.

[0050] The liquid crystal polymer composition of the present invention contains titanium dioxide and mica in addition to the above liquid crystal polymer.

[0051] The crystal structure of the titanium oxide used in the present invention is not particularly limited, and one or more selected from the group consisting of rutile type, anatase type, and brookite type can be used. Among them, rutile type and anatase type are preferable in terms of excellent particle generation reduction effect when ultrasonically cleaned. Further, it may be doped with other metal oxides such as magnesium and calcium to improve dispersion in the resin.

[0052] The titanium oxide used in the present invention can also be used after treating its surface with a known coupling agent (for example, silane coupling agent, titanate coupling agent, aluminum coupling agent, etc.) or other surface treatment agents.

[0053] The average particle diameter of the titanium oxide is preferably 0.5 μm or less, more preferably 0.03 - 0.48 μm, still more preferably 0.05 - 0.26 μm, particularly preferably 0.07 - 0.25 μm, and most preferably 0.08 - 0.20 μm. When the average particle diameter of the titanium oxide exceeds 0.5 μm, the generation of particles tends to be difficult to reduce.

[0054] In this specification and the claims, "average particle diameter" means the volume-based cumulative 50% diameter of particles that can be determined by the laser diffraction scattering method. That is, the particle size distribution is measured by the laser diffraction scattering method, the cumulative curve is obtained with the total volume of the particle population as 100%, and it is the particle diameter at the point where the cumulative volume becomes 50% on the cumulative curve.

[0055] The content of titanium oxide in the liquid crystal polymer composition of the present invention is 1 - 50 parts by mass with respect to 100 parts by mass of the liquid crystal polymer, preferably 2 - 40 parts by mass, more preferably 3 - 30 parts by mass, and particularly preferably 5 - 25 parts by mass. 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, the fluidity becomes insufficient and the wear of the cylinder of the molding machine and the mold increases.

[0056] The mica used in the present invention is a pulverized product of a silicate mineral mainly composed of potassium aluminum silicate hydrate, which may contain magnesium, sodium, iron, etc. in addition to aluminum and potassium, and examples thereof include muscovite, phlogopite, biotite, synthetic mica, etc. Among these, muscovite is preferred in terms of good hue and easy availability.

[0057] The mica used in the present invention may be surface-treated with a silane coupling agent or the like, or may be granulated with a binder to be in a granular form.

[0058] The mica used in the present invention preferably has an average particle size of 5 to 100 μm, more preferably 10 to 80 μm, and particularly preferably 20 to 60 μm. The average particle size of mica is the volume-based cumulative 50% diameter of particles that can be determined by the laser diffraction scattering method.

[0059] 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 particularly preferably 5 to 25 parts by mass with respect to 100 parts by mass of the liquid crystal polymer. If the content of mica is less than 1 part by mass, the effect of suppressing particle generation is insufficient, and if it exceeds 50 parts by mass, the fluidity becomes insufficient.

[0060] In addition, the content ratio of titanium oxide and mica in the liquid crystal polymer composition of the present invention (parts by mass of titanium oxide / parts by mass of mica) is 0.1 to 10, preferably 0.2 to 5, more preferably 0.3 to 3.5, still more preferably 0.4 to 2.5, and particularly preferably 0.5 to 2. When the content ratio of titanium oxide and mica is less than 0.1, the effect of suppressing particle generation cannot be obtained, and when the content ratio of titanium oxide and mica exceeds 10, the effect of improving warpage cannot be obtained.

[0061] In the liquid crystal polymer composition of the present invention, graphite may be further contained for the purpose of further suppressing the occurrence of warpage in the molded article. The graphite used in the present invention may be natural graphite, artificial graphite, or a combination of two or more of them. Graphite having a high fixed carbon content, low ash content such as silicon oxide, and high crystallinity is preferable.

[0062] The average particle diameter of the graphite is usually 5 to 100 μm, preferably 5 to 80 μm, more preferably 5 to 60 μm. The average particle diameter of the graphite is the volume-based cumulative 50% diameter of the particles that can be determined by the laser diffraction scattering method.

[0063] When containing graphite, 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, and particularly preferably 5 to 10 parts by mass with respect to 100 parts by mass of the liquid crystal polymer. When the content of graphite is less than 0.1 part by mass, it is difficult to obtain a further warpage improvement effect, and when the content of graphite exceeds 20 parts by mass, the fluidity tends to become insufficient.

[0064] 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, more preferably 0.05 to 1.0 parts by mass. When the content of the higher fatty acid ester is equal to or higher than the above lower limit value, the occurrence of swelling is further suppressed, and when the content of the higher fatty acid ester is equal to or lower than the above 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 part by mass, swelling is likely to occur, and when it exceeds 1.3 parts by mass, blisters are likely to occur.

[0065] The higher fatty acids that are raw materials for the higher fatty acid esters and / or higher fatty acid metal salts used in the present invention preferably have 10 or more carbon atoms. Examples of such higher fatty acids include capric acid, lauric acid, myristic acid, Pa luminic acid, stearic acid, arachidic acid, behenic acid, lignoceric acid, montanic acid, and the like. Among these, stearic acid and montanic acid are preferred.

[0066] Examples of the alcohol that is a raw material for the ester include stearyl alcohol, behenyl alcohol, glycerin, sorbitan, propylene glycol, pentaerythritol, polyoxyethylene bisphenol A, and the like.

[0067] In addition, examples of the metal that constitutes the metal salt include alkali metals such as lithium, sodium, and potassium, alkaline earth metals such as magnesium, calcium, and barium, or zinc, etc. Among them, alkaline earth metals are preferably used. Specific examples of the 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, barium montanate, aluminum montanate, calcium palmitate, magnesium palmitate, and barium palmitate. Among these, calcium stearate and calcium montanate are preferably used in terms of cost and maintaining the physical properties of the molded product.

[0068] The higher fatty acid esters and / or higher fatty acid metal salts used in the present invention are preferably in powder or particle form in order to facilitate mixing with the liquid crystal polyester resin composition.

[0069] The liquid crystal polymer composition of the present invention may further contain other resin components as long as the object of the present invention is not impaired. Examples of other resin components include thermoplastic resins such as polyamide, polyester, polyacetal, polyphenylene ether and its modified products, polysulfone, polyethersulfone, polyetherimide, polyamideimide, and thermosetting resins such as phenol resin, epoxy resin, and polyimide resin.

[0070] Other resin components can be contained alone or in combination of two or more. The content of other resin components is not particularly limited and may be appropriately determined according to the use and 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 preferably added in the range of 0.1 to 100 parts by mass, more preferably 0.2 to 80 parts by mass.

[0071] The liquid crystal polymer composition of the present invention may contain other fibrous, plate-like, or granular inorganic fillers or organic fillers as long as the effects of the present invention are not impaired.

[0072] 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 20 parts by mass or less, and still more preferably 10 parts by mass or less with respect to 100 parts by mass of the liquid crystal polyester. When the content of these other fillers exceeds the above upper limit value, the molding processability tends to decrease and the thermal stability tends to deteriorate.

[0073] Examples of other fibrous fillers include milled glass, silica alumina fiber, alumina fiber, carbon fiber, aramid fiber, polyarylate fiber, polybenzimidazole fiber, potassium titanate whisker, aluminum borate whisker, etc., and these can be used alone or in combination of two or more.

[0074] Examples of other plate-shaped fillers include silicates such as kaolin, clay, vermiculite, feldspar powder, acid clay, waxstone clay, sericite, sillimanite, bentonite, glass flakes, slate powder, and silane; carbonates such as calcium carbonate, chalk, barium carbonate, magnesium carbonate, and dolomite; sulfates such as barite powder, precipitated calcium sulfate, calcined gypsum, and barium sulfate; hydroxides such as hydrated alumina; oxides such as alumina, antimony oxide, magnesia, zinc white, silica, silica sand, quartz, white carbon, and diatomaceous earth; sulfides such as molybdenum disulfide; and plate-shaped wollastonite. These can be used alone or in combination of two or more.

[0075] Examples of other granular fillers include calcium carbonate, glass beads, and barium sulfate. These can be used alone or in combination of two or more.

[0076] In addition, the liquid crystal polymer composition of the present invention can contain other additives other than those described above as long as the effects of the present invention are not impaired.

[0077] Examples of other additives include, for example, polysiloxane, fluororesin, etc. which are mold release improvers; dyes, pigments, carbon black, etc. which are colorants; flame retardants, antistatic agents, surfactants; phosphorus-based antioxidants, phenolic antioxidants, sulfur-based antioxidants, etc. which are antioxidants; weathering agents, heat stabilizers, neutralizing agents, etc. These additives may be used alone or in combination of two or more.

[0078] The content of these other additives is preferably 0.1 to 10 parts by mass, more preferably 0.5 to 5 parts by mass, based on 100 parts by mass of the liquid crystal polymer. If the content of these other additives exceeds the above upper limit value, the moldability tends to decrease and the thermal stability tends to deteriorate.

[0079] A liquid crystal polymer, titanium oxide, mica, and, if desired, graphite, a higher fatty acid ester or a metal salt of a higher fatty acid, other resin components, other fibrous, plate-like, granular inorganic fillers or organic fillers, other additives, etc. are blended in a predetermined composition and melt-kneaded using a Banbury mixer, a kneader, a single-screw or twin-screw extruder, etc. to obtain the liquid crystal polymer composition of the present invention.

[0080] 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, etc. to obtain a desired molded product.

[0081] Molded products made of a liquid crystal polymer composition usually have a surface of the molded product that is easily peeled off, and when ultrasonically cleaned, fibrillation occurs where the surface peels off and fuzzes, and small powders and dusts (hereinafter referred to as particles) made of the resin composition are likely to be generated from this fibrillated portion. According to the liquid crystal polymer composition of the present invention, since the generation of particles is suppressed, good optical characteristics can be obtained without becoming foreign matter during the assembly and use of the molded product in an optical member such as a camera module.

[0082] Further, the liquid crystal polymer composition of the present invention exhibits an extremely small amount of warpage. The amount of warpage can be measured by the warpage amount measurement method described below.

[0083] 〈Definition and measurement method of warpage amount〉 In this specification, the "amount of warpage" means a value obtained by subtracting the thickness of the test piece (0.5 mm) from the maximum sag height using a three-dimensional measuring instrument (for example, KEYENCE Corporation's one-shot 3D VR-3000) to mold a planar test piece (thickness 0.5 mm, longitudinal and transverse lengths 17 mm, width of the central slit-like step 3 mm and thickness 0.25 mm) having a slit-like step in the central portion under the conditions described below using an injection molding machine (for example, NEX15-1E manufactured by Nissei Plastic Industrial Co., Ltd.).

[0084] Thus, the molded article composed of the liquid crystal polymer composition of the present invention reduces particle generation during ultrasonic cleaning and suppresses the occurrence of warpage in the molded article. Therefore, it is suitably used for electronic components such as connectors, switches, relays, capacitors, coils, transformers, camera modules, and antennas. It is particularly useful for camera modules.

Examples

[0085] Hereinafter, the present invention will be described by way of examples, but the present invention is not limited to the following examples. The measurement of melt viscosity, tensile strength, flexural strength, number of particle generations, and warpage amount in the examples was carried out by the methods described below.

[0086] 〈Melt Viscosity〉 Using a melt viscosity measuring device (Capillograph 1D manufactured by Toyo Seiki Co., Ltd.), with a capillary of 1.0 mmφ × 10 mm, the melt viscosity of the sample was measured at a temperature of the crystal melting temperature (Tm) + 20°C of the sample under the condition of a shear rate of 1000 sec -1 .

[0087] 〈Tensile Strength〉 Using an injection molding machine (UH1000-110 manufactured by Nissei Plastic Industrial Co., Ltd.), injection molding was carried out at a cylinder temperature of 350°C and a mold temperature of 70°C to produce an ASTM No. 4 dumbbell test piece. It was measured in accordance with ASTM D638 using an INSTRON 5567 (universal testing machine manufactured by Instron Japan K.K.).

[0088] 〈Flexural Strength〉 Measurement was carried out in accordance with ASTM D790 using the same test piece as the test piece used for the measurement of the heat distortion temperature under load.

[0089] 〈Number of Particle Generations〉 The same test piece as that used for the load deflection temperature measurement was placed in a cylindrical glass container with 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 part was not immersed in the water. Then, the cylindrical glass container was placed in an ultrasonic cleaning tank (US-102 manufactured by SND Co., Ltd.) with a length of 140 mm, a width of 240 mm, and a depth of 100 mm 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 with a particle diameter of 2 μm or more contained in 1 mL of pure water [debris (particles) peeled off from the test piece] was measured three times using a particle counter (LiQuilaz-05 manufactured by Spectris Co., Ltd.), and the average value was taken as the measurement result. Less than 500 was indicated as "〇", 500 or more and less than 1000 was indicated as "△", and 1000 or more was indicated as "×".

[0090] 〈Amount of warpage〉 Using an injection molding machine (NEX15-1E manufactured by Nissei Plastic Industrial Co., Ltd.), a flat test piece having a slit-like step in the central part shown in Fig. 1 (thickness: 0.5 mm, longitudinal and transverse lengths: 17 mm, width of the central slit-like step: 3 mm, and thickness: 0.25 mm) was molded under the conditions described in Table 1. After leaving this test piece standing at 23°C and a relative humidity of 50% for 24 hours, using a three-dimensional measuring instrument (Keyence's One-shot 3D VR-3000), the value obtained by subtracting the test piece thickness (0.5 mm) from the maximum warpage height was defined as the amount of warpage.

[0091] [Table 1]

[0092] [Synthesis Example 1 (Synthesis of liquid crystal polymer)] Into a reaction vessel equipped with a stirring device with a torque meter and a distillation tube, 431 g (48 mol%) of p-hydroxybenzoic acid, 196 g (16 mol%) of 6-hydroxy-2-naphthoic acid, 194 g (18 mol%) of terephthalic acid, and 129 g (18 mol%) of hydroquinone were charged so that the total amount was 6.5 mol. Further, acetic anhydride in an amount 1.03 times the molar amount of the hydroxyl groups of all the monomers was charged, and deacetic acid polymerization was carried out under the following conditions.

[0093] The temperature was raised from room temperature to 150 °C in 1 hour under a nitrogen gas atmosphere and held at the same temperature for 30 minutes. Then, while distilling off the by-produced acetic acid, the temperature was raised to 350 °C over 7 hours, and then the pressure was reduced to 5 mmHg over 80 minutes. When a predetermined torque was shown, the polymerization reaction was terminated, the content of the reaction vessel was taken out, and pellets of the liquid crystal polymer were obtained by a pulverizer. The amount of acetic acid distilled off during polymerization was almost the same as the theoretical value.

[0094] 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 Laboratory 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

[0095] Examples 1 to 7 (Example 6 is a reference example) and Comparative Examples 1 to 5 The LCP synthesized in Synthesis Example 1, titanium oxide, mica, talc, graphite, and higher fatty acid ester were blended so as to have the contents (parts by mass) shown in Table 1, and melt kneading was performed at 350 °C using a twin-screw extruder (TEX-30 manufactured by Nippon Steel Corporation) to obtain pellets of the liquid crystal polymer composition. By the above method, the melt viscosity, tensile strength, flexural strength, number of generated particles, and warpage amount were measured. The results are shown in Table 2 shown below.

[0096] Table 2 As shown in the table below, in all of the liquid crystal polymer compositions of Examples 1 to 7, the number of particles having a particle diameter of 2 μm or more was less than 1000, and the warpage amount was small.

[0097] On the other hand, the liquid crystal polymer compositions of Comparative Examples 1 to 5 resulted in unfavorable outcomes for at least one of particle generation or warpage amount.

[0098]

Table 2

Claims

1. A liquid crystal polymer composition containing 100 parts by mass of a liquid crystal polymer, 3 to 40 parts by mass of titanium oxide, and 3 to 50 parts by mass of mica, wherein the ratio of the content of titanium oxide (parts by mass) to the content of mica (parts by mass) is 0.1 to 10, The liquid crystal polymer is a liquid crystal polyester resin containing repeating units represented by formula (I) and formula (II) 【Chemical Formula 1】 and having an average particle diameter of titanium oxide of 0.03 to 0.5 μm or less and an average particle diameter of mica of 5 to 100 μm.

2. The liquid crystal polymer is an all-aromatic liquid crystal polyester resin composed of repeating units represented by formula (I) to formula (IV), and the liquid crystal polymer composition according to claim 1.

3. 【Chemical Formula 2】 [wherein, Ar １ and Ar ２ each represents a divalent aromatic group] The liquid crystal polymer composition according to claim 2, which is one or more repeating units selected from aromatic groups represented by

4. The repeating units represented by formulas (III) to (IV) are Ar １ and Ar ２ are each independently of one another, formulas (1) to (4) 【Chemical Formula 3】

5. The liquid crystal polymer composition according to any one of claims 1 to 4, further containing graphite. The repeating unit represented by formula (III) is Ar １ is a repeating unit which is an aromatic group represented by formula (1), and the repeating unit represented by formula (IV) is a repeating unit which is an aromatic group represented by formula (1), ２ The liquid crystal polymer composition according to claim 2 or 3, wherein R is a repeating unit which is an aromatic group represented by formula (1) and / or R is a repeating unit which is an aromatic group represented by formula (3).

6. A molded article composed of the liquid crystal polymer composition according to any one of claims 1 to 5.

7. The molded article according to claim 6, which is a component constituting one selected from the group consisting of a connector, a switch, a relay, a capacitor, a coil, a transformer, a camera module, and an antenna. ​ ​

Images