JP2023065057A - Liquid crystalline polyester resin composition - Google Patents

Abstract

To provide a liquid crystalline polyester resin composition which is improved in mechanical properties and heat resistance while maintaining sliding properties.SOLUTION: There is provided a liquid crystalline polyester resin composition which comprises a liquid crystalline polyester containing a repeating unit represented by the formulas (I) to (III) [wherein, Ar1 and Ar2 each represent one or more divalent aromatic groups, p, q and r are composition ratios (mol%) of each repeating unit in the liquid crystal polyester, respectively and satisfy the following conditions: 35≤p≤90, 5≤q≤30 and 5≤r≤30], a fluororesin having an average particle diameter of 25 μm or more and a plate-like filler, wherein the content of the fluororesin is 1 to 30 pts.mass and the content of the plate-like filler is 5 to 80 pts.mass based on 100 pts.mass of the liquid crystalline polyester.SELECTED DRAWING: None

Description

TECHNICAL FIELD The present invention relates to a liquid crystal polyester resin composition having improved mechanical properties and heat resistance while maintaining slidability.

Liquid crystalline polyester is excellent in mechanical properties such as heat resistance and rigidity, chemical resistance, dimensional accuracy, etc. Therefore, its use is expanding not only for molded products but also for various applications such as fibers and films. Especially in the field of information and communication such as personal computers and mobile phones, parts are becoming more highly integrated, smaller, thinner, and lower in height. is formed in many cases, and the amount of liquid crystal polymer used has increased significantly, taking advantage of the excellent moldability of liquid crystal polymer, that is, good fluidity and no burrs, which are not found in other polymers. there is

As described above, liquid crystal polymers have various excellent properties, but when used as sliding parts due to the large anisotropy of molded articles, they are likely to be damaged due to wear.

In order to solve such problems, for example, Patent Document 1 describes a method of improving the slidability of a liquid crystal polymer composition by incorporating a fluororesin into the liquid crystal polymer.

JP-A-5-105804

However, when the fluororesin is incorporated into the liquid crystalline polyester, the heat resistance of the resin composition is lowered, so there have been cases where the resin composition is deformed when processed at high temperature as a molded product for use in electric/electronic parts, automobile parts, and the like. An object of the present invention is to provide a liquid crystalline polyester resin composition having improved mechanical properties and heat resistance while maintaining slidability.

In view of the above problems, the present inventors have made intensive studies and found that the slidability of the liquid crystal polyester resin composition can be improved by adding a fluororesin having a specific average particle size and a plate-like filler to the liquid crystal polyester. The inventors have found that the mechanical properties and heat resistance are improved while maintaining the same, and have completed the present invention.

［式中、
Ａｒ_１およびＡｒ_２は、それぞれ１種または２種以上の２価の芳香族基を表し、ｐ、ｑおよびｒは、それぞれ、液晶ポリエステル中での各繰返し単位の組成比（モル％）であり、以下の条件を満たす：
３５≦ｐ≦９０、
５≦ｑ≦３０、および
５≦ｒ≦３０］
で表される繰返し単位を含む液晶ポリエステルと、
平均粒子径が２５μｍ以上であるフッ素樹脂と、
板状充填材と
を含有し、液晶ポリエステル１００質量部に対して、フッ素樹脂の含有量は１～３０質量部、板状充填材の含有量は５～８０質量部である液晶ポリエステル樹脂組成物。
〔２〕式（ＩＩ）および／または式（ＩＩＩ）は、Ａｒ_１およびＡｒ_２が、互いに独立して、式（１）～（４）

からなる群から選択される芳香族基である繰返し単位の１種または２種以上を含む、〔１〕に記載の液晶ポリエステル樹脂組成物。
〔３〕フッ素樹脂はポリテトラフルオロエチレンである、〔１〕または〔２〕に記載の液晶ポリエステル樹脂組成物。
〔４〕板状充填材はタルク、マイカおよびカオリンからなる群から選択される１種以上である、〔１〕～〔３〕のいずれかに記載の液晶ポリエステル樹脂組成物。
〔５〕２７０℃において、長さ１０ｍｍ、幅４．５ｍｍ、厚さ３．２ｍｍの板状試験片の厚さ方向に１０００ｍＮの荷重をかけたときの凹み量が４．０μｍ以下である、〔１〕～〔４〕のいずれかに記載の液晶ポリエステル樹脂組成物。
〔６〕〔１〕～〔５〕のいずれかに記載の液晶ポリエステル樹脂組成物から構成される成形品。
〔７〕成形品はインストルメントパネル、ドアパネル、ドアトリム、ミドルボード、ドアオーナメント、カバーシートリヤアンダートレイ、トラックカバー、サービスホールカバー、ピラー、スカッフプレート、センターコンソール、カップホルダー、およびコラムカバーからなる群から選択される１種を構成する部品である、〔６〕に記載の成形品。 That is, the present invention includes the following preferred aspects.
[1] Formulas (I) to (III)

[In the formula,
Ar ₁ and Ar ₂ each represent one or more divalent aromatic groups, and p, q and r are each the composition ratio (mol%) of each repeating unit in the liquid crystalline polyester. , satisfying the following conditions:
35≦p≦90,
5≤q≤30, and 5≤r≤30]
A liquid crystalline polyester containing a repeating unit represented by
A fluororesin having an average particle size of 25 μm or more;
A liquid crystal polyester resin composition containing a plate-like filler, wherein the content of the fluororesin is 1 to 30 parts by mass and the content of the plate-like filler is 5 to 80 parts by mass with respect to 100 parts by mass of the liquid crystal polyester. .
[2] formula (II) and/or formula (III), wherein Ar ₁ and Ar ₂ are independently represented by formulas (1) to (4)

The liquid crystalline polyester resin composition according to [1], which contains one or more repeating units that are aromatic groups selected from the group consisting of:
[3] The liquid crystal polyester resin composition according to [1] or [2], wherein the fluororesin is polytetrafluoroethylene.
[4] The liquid crystalline polyester resin composition according to any one of [1] to [3], wherein the plate-like filler is one or more selected from the group consisting of talc, mica and kaolin.
[5] At 270 ° C., the amount of depression is 4.0 μm or less when a load of 1000 mN is applied in the thickness direction of a plate-shaped test piece having a length of 10 mm, a width of 4.5 mm, and a thickness of 3.2 mm. 1] The liquid crystalline polyester resin composition according to any one of [4].
[6] A molded article composed of the liquid crystalline polyester resin composition according to any one of [1] to [5].
[7] Molded products are selected from the group consisting of instrument panels, door panels, door trims, middle boards, door ornaments, cover seat rear undertrays, truck covers, service hole covers, pillars, scuff plates, center consoles, cup holders, and column covers. The molded article according to [6], which is a component constituting one selected type.

Since the liquid crystalline polyester resin composition of the present invention has improved mechanical properties and heat resistance while maintaining slidability, it is suitably used for various applications such as electric/electronic parts and automobile members. .

The liquid crystalline polyester used in the liquid crystalline polyester resin composition of the present invention is a liquid crystalline polyester that forms an anisotropic melt phase, which is called thermotropic liquid crystalline polyester by those skilled in the art.

The properties of the anisotropic melt phase of the liquid crystalline polyester can be confirmed by a normal deflection inspection method using crossed polarizers, that is, by observing a sample placed on a hot stage under a nitrogen atmosphere.

［式中、
Ａｒ_１およびＡｒ_２は、それぞれ１種または２種以上の２価の芳香族基を表し、ｐ、ｑおよびｒは、それぞれ、液晶ポリエステル中での各繰返し単位の組成比（モル％）であり、以下の条件を満たす：
３５≦ｐ≦９０、
５≦ｑ≦３０、および
５≦ｒ≦３０。］ As the liquid crystalline polyester used in the present invention, those containing repeating units represented by formulas (I) to (III) are preferably used.

[In the formula,
Ar ₁ and Ar ₂ each represent one or more divalent aromatic groups, and p, q and r are each the composition ratio (mol%) of each repeating unit in the liquid crystalline polyester. , satisfying the following conditions:
35≦p≦90,
5≤q≤30, and 5≤r≤30. ]

The composition ratio p in formula (I) is 35 to 90 mol%, preferably 40 to 85 mol%, more preferably 45 to 80 mol%, and even more preferably 50 to 65 mol%.

The composition ratio q according to formula (II) and the composition ratio r according to formula (III) are each 5 to 30 mol%, preferably 7.5 to 30 mol%, and 10 to 27.5 mol%. More preferably, 17.5 to 25 mol % is even more preferable. q and r are preferably in equimolar amounts.

In the above repeating unit, for example, Ar ₁ (or Ar ₂ ) represents two or more divalent aromatic groups, which means that the repeating unit represented by formula (II) (or (III)) is It means that two or more types are contained in the group according to the type of the divalent aromatic group. In this case, the composition ratio q according to formula (II) (or the composition ratio r according to formula (III)) represents the total composition ratio of two or more repeating units.

Specific examples of monomers that give the repeating unit represented by formula (I) include 6-hydroxy-2-naphthoic acid, and its acylates, ester derivatives, and ester-forming derivatives such as acid halides. .

Specific examples of monomers that give repeating units represented by formula (II) include aromatic diols such as hydroquinone, resorcinol, 2,6-dihydroxynaphthalene, 2,7-dihydroxynaphthalene, 1,6- Dihydroxynaphthalene, 1,4-dihydroxynaphthalene, 4,4'-dihydroxybiphenyl, 3,3'-dihydroxybiphenyl, 3,4'-dihydroxybiphenyl, 4,4'-dihydroxybiphenyl ether, etc., and alkyl and alkoxy thereof Alternatively, halogen-substituted products and ester-forming derivatives such as acylated products thereof may be mentioned.

Specific examples of monomers that give repeating units represented by formula (III) include aromatic dicarboxylic acids such as terephthalic acid, isophthalic acid, 2,6-naphthalenedicarboxylic acid, and 1,6-naphthalenedicarboxylic acid. , 2,7-naphthalenedicarboxylic acid, 1,4-naphthalenedicarboxylic acid, 4,4′-dicarboxybiphenyl, etc., and alkyl, alkoxy or halogen-substituted products thereof, ester derivatives thereof, esters such as acid halides, etc. Formative derivatives are mentioned.

Among them, as the liquid crystalline polyester, Ar ₁ and Ar ₂ related to the repeating units represented by the formulas (II) and (III) are independently aromatic aromatic represented by the formulas (1) to (4) Those containing one or more selected from the group consisting of groups are preferably used.

Among these, as the repeating unit represented by formula (II), the aromatic groups represented by formulas (1) and (3) have reactivity during polymerization and the mechanical properties and heat resistance of the obtained liquid crystalline polyester. It is more preferable because it is easy to adjust the properties, crystal melting temperature, and moldability to appropriate levels. Monomers that provide these repeating units include 4,4'-dihydroxybiphenyl and hydroquinone, and ester-forming derivatives thereof.

Further, as the repeating unit represented by the formula (III), the aromatic group represented by the formula (1) has an appropriate level of mechanical properties, heat resistance, crystal melting temperature and moldability of the obtained liquid crystalline polyester. It is more preferable because it is easy to adjust to Monomers that provide these repeating units include terephthalic acid and ester-forming derivatives thereof.

Furthermore, as the liquid crystal polyester, the repeating unit represented by formula (II) includes at least two repeating units represented by formula (1) and formula (3), and the repeating unit according to formula (3) is represented by formula ( Among 100 mol % of repeating units represented by II), those containing preferably 80 to 99.9 mol %, more preferably 85 to 99 mol %, still more preferably 90 to 98 mol % are particularly preferably used.

In the liquid crystalline polyester of the present invention, the total composition ratio [p+q+r] of the repeating units is preferably 100 mol %, but other repeating units may be further included within a range not impairing the object of the present invention.

Examples of monomers that give other repeating units include other aromatic hydroxycarboxylic acids, aromatic hydroxyamines, aromatic diamines, aromatic aminocarboxylic acids, aromatic hydroxydicarboxylic acids, aliphatic diols, aliphatic dicarboxylic acids, Aromatic mercaptocarboxylic acids, aromatic dithiols, aromatic mercaptophenols and combinations thereof, and the like.

Specific examples of other aromatic hydroxycarboxylic acids include 4-hydroxybenzoic acid, 3-hydroxybenzoic acid, 2-hydroxybenzoic acid, 5-hydroxy-2-naphthoic acid, and 3-hydroxy-2-naphthoic acid. , 4′-hydroxyphenyl-4-benzoic acid, 3′-hydroxyphenyl-4-benzoic acid, 4′-hydroxyphenyl-3-benzoic acid and alkyl, alkoxy or halogen substituted versions thereof, and acylated products thereof, Examples include ester derivatives and ester-forming derivatives such as acid halides.

Specific examples of other aromatic diols include resorcin, 2,6-dihydroxynaphthalene, 2,7-dihydroxynaphthalene, 1,6-dihydroxynaphthalene, 1,4-dihydroxynaphthalene, 4,4'-dihydroxybiphenyl , 3,3′-dihydroxybiphenyl, 3,4′-dihydroxybiphenyl, 4,4′-dihydroxybiphenyl ether and other aromatic diols and their alkyl, alkoxy or halogen substitutions, and their acylates. and sexual derivatives.

Specific examples of other aromatic dicarboxylic acids include terephthalic acid, isophthalic acid, 1,6-naphthalenedicarboxylic acid, 2,7-naphthalenedicarboxylic acid, 1,4-naphthalenedicarboxylic acid, 4,4′-dicarboxylic acid, Aromatic dicarboxylic acids such as carboxybiphenyl, alkyl-, alkoxy- or halogen-substituted products thereof, ester derivatives thereof, and ester-forming derivatives such as acid halides are included.

Specific examples of aromatic hydroxydicarboxylic acids that are monomers that provide other repeating units include 3-hydroxy-2,7-naphthalenedicarboxylic acid, 4-hydroxyisophthalic acid, and 5-hydroxyisophthalic acid. Hydroxyaromatic dicarboxylic acids and alkyl-, alkoxy- or halogen-substituted products thereof, as well as ester-forming derivatives such as acylates, ester derivatives and acid halides thereof.

Specific examples of aromatic hydroxylamines that are monomers that give other repeating units include 4-aminophenol, 3-aminophenol, 4-amino-1-naphthol, 5-amino-1-naphthol, 8 aromatic hydroxyamines such as -amino-2-naphthol, 4-amino-4'-hydroxybiphenyl and their alkyl, alkoxy or halogen substituted products, and ester-forming derivatives such as their acylated products.

Specific examples of aromatic diamines that are monomers that give other repeating units include 1,4-diaminobenzene, 1,3-diaminobenzene, 1,5-diaminonaphthalene, 1,8-diaminonaphthalene, etc. and their alkyl-, alkoxy- or halogen-substituted versions, and amide-forming derivatives such as acylates thereof.

Specific examples of aromatic aminocarboxylic acids that are monomers that give other repeating units include aromatic aminocarboxylic acids such as 4-aminobenzoic acid, 3-aminobenzoic acid and 6-amino-2-naphthoic acid. Acids and alkyl, alkoxy or halogen substituted versions thereof, and ester-forming derivatives such as acylates, ester derivatives and acid halides thereof are included.

The compositional ratio of repeating units provided by these other monomer components is preferably 10 mol % or less in the entire repeating units.

The crystal melting temperature of the liquid crystalline polyester used in the present invention is not particularly limited, but from the viewpoint of mechanical properties, heat resistance and low temperature workability, it is preferably 310 to 360 ° C., and 315 to 355 ° C. Some are more preferred, those between 318 and 350°C are more preferred, and those between 320 and 340°C are even more preferred.

In the present specification and claims, the term "crystal melting temperature" refers to the crystal melting temperature measured at a heating rate of 20°C/min with a differential scanning calorimeter (hereinafter abbreviated as DSC). It is obtained from the peak temperature. More specifically, after observing the endothermic peak temperature (Tm1) observed when measuring the liquid crystalline polyester sample under the temperature rising condition of 20 ° C./min from room temperature, 10 After holding the sample for 20 minutes and then cooling the sample to room temperature under the condition of temperature decrease of 20°C/minute, the endothermic peak was measured again under the condition of temperature increase of 20°C/minute. It is the crystal melting temperature of polyester. As a measuring instrument, for example, Exstar6000 manufactured by Seiko Instruments Inc. can be used.

The liquid crystalline polyester used in the present invention was measured by a capillary rheometer (Capilograph 1D manufactured by Toyo Seiki Co., Ltd.) using a capillary of 0.7 mmφ × 10 mm under the conditions of a shear rate of 1000 s ^-1 and a crystal melting temperature of +30 ° C. It preferably has a melt viscosity of 1 to 1000 Pa·s, more preferably 5 to 300 Pa·s, as measured by .

The method for producing the liquid crystalline polyester used in the present invention will be described below.
The method for producing the liquid crystalline polyester used in the present invention is not particularly limited, and a known polycondensation method for forming an ester bond or the like comprising a combination of the above monomers, such as a melt acidolysis method or a slurry polymerization method, may be used. can be done.

The melt acidolysis method, which is a suitable method for producing the liquid crystalline polyesters used in the present invention, involves first heating the monomers to form a melt of reactants followed by continuing the reaction. to obtain molten polyester. A vacuum may be applied to facilitate removal of volatiles (eg, acetic acid, water, etc.) by-produced in the final stage of condensation.

Slurry polymerization is a process in which polymerizable monomers are reacted in the presence of a heat exchange fluid, resulting in a solid product suspended in the heat exchange medium.

In both the melt acidolysis method and the slurry polymerization method, the polymerizable monomer component used in the production of the liquid crystalline polyester reacts at normal temperature as a modified form in which the hydroxyl group is acylated, that is, as a lower acylated product. can also be provided. The lower acyl group preferably has 2 to 5 carbon atoms, 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.

The lower acylated product of the polymerizable monomer may be one synthesized in advance by acylation separately, or an acylating agent such as acetic anhydride is added to the polymerizable monomer at the time of production of the liquid crystalline polyester in the reaction system. can also be generated with

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

Specific examples of catalysts include organotin compounds such as dialkyltin oxide (e.g., dibutyltin oxide) and diaryltin oxide; titanium dioxide; antimony trioxide; organotitanium compounds such as alkoxytitanium silicates and titanium alkoxides; earth metal salts (e.g. sodium acetate, potassium acetate); inorganic acid salts (e.g. potassium sulfate); gaseous acid catalysts such as Lewis acids (e.g. boron trifluoride) and hydrogen halides (e.g. hydrogen chloride); .

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

The liquid crystalline polyester obtained by such a polycondensation reaction is usually extracted from the polymerization reactor in a molten state, processed into pellets, flakes, or powder, and subjected to melt-kneading with other components. be done.

Pellets, flakes, or powdery liquid crystalline polyesters are substantially solidified under reduced pressure, vacuum, or in an inert gas atmosphere such as nitrogen or helium for the purpose of increasing the molecular weight and improving the heat resistance. You may heat-process in a phase state.

From the viewpoint of improving slidability, the liquid crystal polyester resin composition of the present invention contains a fluororesin in addition to the above liquid crystal polyester. The average particle size of the fluororesin is 25 μm or more. If the average particle size is less than 25 μm, it is difficult to achieve both mechanical strength and heat resistance and sliding wear resistance. The average particle size is preferably 30 to 80 μm, more preferably 33 to 70 μm, because it is easy to achieve both of the above. In this specification, the average particle size refers to the volume-based median value (median size) measured by a laser diffraction/scattering particle size distribution measurement method.

The fluororesin used in the present invention includes polytetrafluoroethylene (PTFE), perfluoroalkoxyalkane (PFA), polyvinylidene fluoride (PVDF), polyvinyl fluoride, tetrafluoroethylene/ethylene copolymer, tetrafluoroethylene/per Fluoropropylene copolymer, tetrafluoroethylene/perfluoroalkyl vinyl ether copolymer, fluoroethylene/vinyl ether copolymer, polychlorotrifluoroethylene (PCTFE), chlorotrifluoroethylene/ethylene copolymer, fluoroolefin/acrylic acid Examples include ester copolymers and tetrafluoroethylene/perfluorodioxol copolymers. Among these, PTFE is preferable from the viewpoint of improving the slidability of the liquid crystal polyester resin composition.

The content of the above-mentioned fluororesin in the liquid crystal polyester resin composition of the present invention is 1 to 30 parts by mass, preferably 2 to 29 parts by mass, more preferably 3 to 30 parts by mass with respect to 100 parts by mass of the liquid crystal polyester. 28 parts by mass, more preferably 5 to 27 parts by mass. When the content of the fluororesin is within the above range, the mechanical properties and heat resistance can be improved while maintaining the slidability of the liquid crystal polyester resin composition.

The liquid crystalline polyester resin composition of the present invention may further contain other resin components in addition to the above-mentioned fluororesin as long as the object of the present invention is not impaired. Other resin components include, for example, thermoplastic resins such as polyamide, polyester, polyacetal, polyphenylene ether and modified products thereof, polysulfone, polyethersulfone, polyetherimide, and polyamideimide, phenol resin, epoxy resin, polyimide resin, and the like. thermosetting resin. Other resin components can be contained singly 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 application and purpose of the liquid crystal polyester resin composition. Typically, the total content of the other resins is preferably 0.1 to 100 parts by mass, more preferably 0.2 to 80 parts by mass, based on 100 parts by mass of the liquid crystal polyester.

From the viewpoint of slidability, mechanical properties and heat resistance, the liquid crystalline polyester resin composition of the present invention contains a plate-like filler in addition to the above liquid crystalline polyester and fluororesin.

Plate-like fillers used in the present invention include talc, mica, kaolin, clay, vermiculite, feldspar powder, acid clay, roseite clay, sericite, sillimanite, bentonite, glass flakes, slate powder, silicates such as silane, Calcium carbonate, chalk, barium carbonate, magnesium carbonate, carbonates such as dolomite, barite powder, precipitated calcium sulfate, plaster of Paris, sulfates such as barium sulfate, hydroxides such as hydrated alumina, alumina, antimony oxide, magnesia , plate-like titanium oxide, zinc white, silica, silica sand, quartz, white carbon, oxides such as diatomaceous earth, sulfides such as molybdenum disulfide, plate-like wollastonite, etc., and these may be used alone or in combination of two. The above can be used together. Among these, talc, mica and kaolin are preferred from the viewpoint of improving the mechanical properties and heat resistance of the liquid crystalline polyester resin composition.

The content of the plate-like filler in the liquid crystal polyester resin composition of the present invention is 5 to 80 parts by mass, preferably 7 to 78 parts by mass, more preferably 10 to 100 parts by mass with respect to 100 parts by mass of the liquid crystal polyester. 76 parts by mass, more preferably 15 to 75 parts by mass. When the content of the plate-like filler is within the above range, the wear resistance can be further improved.

The liquid crystalline polyester resin composition of the present invention may contain other fibrous or granular inorganic fillers or organic fillers in addition to the plate-like fillers as long as the effects of the present invention are not impaired. good.

Other fibrous fillers include, for example, milled glass, silica alumina fiber, alumina fiber, carbon fiber, aramid fiber, polyarylate fiber, polybenzimidazole fiber, potassium titanate whisker, aluminum borate whisker, acicular titanium oxide. , calcium silicate such as wollastonite, xonotlite, calcium titanate, aluminum borate, acicular calcium carbonate, acicular titanium oxide, tetrapod-type zinc oxide, etc., and these may be used alone or in combination of two or more. can be done.

Other particulate fillers include, for example, calcium carbonate and glass beads, and these may be used alone or in combination of two or more.

When the liquid crystal polyester resin composition of the present invention contains an inorganic filler or an organic filler other than the plate-like filler, the content thereof is preferably 0.1 to 30 parts by mass with respect to 100 parts by mass of the liquid crystal polyester. , more preferably 0.5 to 20 parts by mass. When the content of these other fillers exceeds the above upper limit, there is a tendency that moldability is lowered and thermal stability is deteriorated.

In addition, the liquid crystal polyester resin 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, lubricants such as higher fatty acids, higher fatty acid esters, higher fatty acid amides, and higher fatty acid metal salts (here, higher fatty acids refer to those having 10 to 25 carbon atoms, for example). Type improver such as polysiloxane, coloring agent such as dye, pigment, carbon black, flame retardant, antistatic agent, surfactant, antioxidant phosphorus antioxidant, phenolic antioxidant, sulfur system antioxidants, weathering agents, heat stabilizers, neutralizers, and the like. These additives may be used alone or in combination of two or more.

Additives having an external lubricant effect, such as higher fatty acids, higher fatty acid esters, and higher fatty acid metal salts, may be attached in advance to the surfaces of the pellets of the liquid crystalline polyester resin composition when molding the liquid crystalline polyester resin composition. .

The content of these other additives is preferably 0.1 to 10 parts by weight, more preferably 0.5 to 5 parts by weight, per 100 parts by weight of the liquid crystal polyester. When the content of these other additives exceeds the above upper limit, there is a tendency that moldability is lowered and thermal stability is deteriorated.

A liquid crystalline polyester, a fluororesin, a plate-like filler, and optionally other resin components, other inorganic fillers and/or organic fillers, other additives, etc. are blended in a predetermined composition, and the mixture is mixed with a Banbury mixer, a kneader, and a uniaxial Alternatively, the liquid crystalline polyester resin composition of the present invention can be obtained by melt-kneading using a twin-screw extruder or the like.

The thus obtained liquid crystalline polyester resin composition of the present invention 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 product.

The liquid crystal polyester resin composition of the present invention has a bending strength of preferably 150 MPa or more, more preferably 155 MPa or more, and a bending elastic modulus of preferably 10 in a bending test using an ASTM No. 4 bending test piece having a thickness of 3.2 mm. 0 GPa or more, more preferably 10.5 GPa or more. Although the upper limit of the bending strength is not particularly limited, it is, for example, 200 MPa. Moreover, although the upper limit of the bending elastic modulus is not particularly limited, it is, for example, 20 Gpa. Therefore, the liquid crystalline polyester resin composition of the present invention has a bending strength of, for example, 150 to 200 MPa, 155 to 190 MPa, and a bending elastic modulus of, for example, 10.0 to 20 GPa, 10.5 to 18 GPa.

The liquid crystalline polyester resin composition of the present invention preferably has a tensile modulus of 10 GPa or more, more preferably 11 GPa or more, as measured according to ASTM D638 using an ASTM No. 4 dumbbell test piece having a thickness of 3.2 mm. Although the upper limit of the tensile modulus is not particularly limited, it is, for example, 20 GPa. Therefore, the liquid crystalline polyester resin composition of the present invention has a tensile elastic modulus of, for example, 10 to 20 GPa, 11 to 18 GPa, and the like. A resin composition having a tensile modulus within the above range exhibits high strength and can be a molded article that is difficult to deform in repeated use.

The liquid crystalline polyester resin composition of the present invention has a tensile elongation of preferably 2.0% or less, more preferably 1.5% or less, when measured according to ASTM D638 using an ASTM No. 4 dumbbell test piece having a thickness of 3.2 mm. is. Although the lower limit of the tensile elongation is not particularly limited, it is, for example, 0.1%. Therefore, the liquid crystalline polyester resin composition of the present invention has a tensile elongation of, for example, 0.1 to 2.0%, 0.3 to 1.5%, and the like.

The liquid crystal polyester resin composition of the present invention has excellent slidability. In this specification, the slidability can be evaluated as a coefficient of dynamic friction, and the coefficient of dynamic friction is preferably 0.15 or less, more preferably 0.14 or less, and still more preferably 0.13 or less. is. If the coefficient of dynamic friction exceeds the above upper limit, the slidability tends to be insufficient. The details of the method for measuring the coefficient of dynamic friction are as described in Examples.

The liquid crystalline polyester resin composition of the present invention has excellent heat resistance. In this specification, heat resistance can be evaluated as the amount of dents at high temperatures, and the amount of dents at high temperatures is preferably 4.0 μm or less, more preferably 3.5 μm or less, and still more preferably 3.5 μm or less. , 3.0 μm or less. If the amount of recession at high temperatures exceeds the above upper limit, the heat resistance tends to be insufficient. The details of the method for measuring the amount of depression at high temperatures are as described in Examples.

According to the liquid crystalline polyester resin composition of the present invention, instrument panels, door panels, door trims, middle boards, door ornaments, cover sheet rears, and the like exhibit improved mechanical properties and heat resistance while maintaining slidability. It is suitable for automotive parts such as undertrays, truck covers, service hole covers, pillars, scuff plates, center consoles, cup holders and column covers.

EXAMPLES The present invention will be described below with reference to examples, but the present invention is not limited to the following examples. The bending strength, bending elastic modulus, high-temperature depression amount, and dynamic friction coefficient in the examples were measured and evaluated by the methods described below.

<Bending strength, bending elastic modulus>
Injection molding is performed using an injection molding machine (UH1000-110 manufactured by Nissei Plastic Industry Co., Ltd.) at a cylinder temperature of crystal melting temperature +20 to 40 ° C. and a mold temperature of 70 ° C., and an ASTM No. 4 bending test piece with a thickness of 3.2 mm is prepared. made. For the bending test, a three-point bending test was performed using INSTRON5567 (a universal testing machine manufactured by Instron Japan Co., Ltd.) at a span-to-span distance of 40.0 mm and a compression rate of 1.3 mm/min.

<Tensile modulus, tensile elongation>
Injection molding is performed using an injection molding machine (UH1000-110 manufactured by Nissei Plastic Industry Co., Ltd.) at a cylinder temperature of crystal melting temperature +20 to 40 ° C. and a mold temperature of 70 ° C., and an ASTM No. 4 dumbbell test piece with a thickness of 3.2 mm is made. made. Tensile modulus and tensile elongation were measured using INSTRON5567 (universal testing machine manufactured by Instron Japan Company Limited), using a contact-type extensometer with a gauge length of 25 mm, a test speed of 5 mm/min, and a chuck distance of 64 mm. conditions, each was measured according to ASTM D638.

<High temperature dent test>
Injection molding is performed using an injection molding machine (UH1000-110 manufactured by Nissei Plastic Industry Co., Ltd.) at a cylinder temperature of crystal melting temperature +20 to 40 ° C. and a mold temperature of 70 ° C., and an ASTM No. 4 bending test piece with a thickness of 3.2 mm is prepared. A plate-shaped test piece (length 10 mm×width 4.5 mm×thickness 3.2 mm) was prepared by cutting. In the high-temperature dent test, a thermomechanical analyzer (TMA7100C manufactured by Hitachi High-Tech Science Co., Ltd.) was used to apply a load of 1000 mN in the thickness direction of the test piece at 270 ° C., and the amount of dent in the thickness direction of the test piece (μm ) was measured.

<Dynamic friction coefficient>
Injection molding is performed using an injection molding machine (UH1000-110 manufactured by Nissei Plastic Industry Co., Ltd.) at a cylinder temperature of crystal melting temperature +20 to 40 ° C. and a mold temperature of 70 ° C., and a plate-shaped test piece (length 80 mm × width 80 mm x thickness 1.0 mm). The dynamic friction coefficient was measured using a surface property measuring machine (TYPE: 14FW manufactured by Shinto Kagaku Co., Ltd.) equipped with a SUS304 indenter (manufactured by Teraoka) at a sliding speed of 1200 mm/min and a sliding distance of 10.0 mm ( One way), 1000 sliding times (reciprocating), and an indenter load of 1000 gf, and the dynamic friction coefficient during reciprocating sliding was measured. The coefficient of dynamic friction is a value obtained by calculating the average value of the coefficient of dynamic friction at the 301st to 1000th times.

In the following examples and comparative examples, the following abbreviations represent the following compounds.
BON6: 6-hydroxy-2-naphthoic acid HQ: hydroquinone BP: 4,4'-dihydroxybiphenyl TPA: terephthalic acid POB: parahydroxybenzoic acid

[Synthesis Example 1 (LCP-1)]
BON6: 660.5 g (54.0 mol %), BP: 254.2 g (21.0 mol %), HQ: 14.3 g ( 2.0 mol %) and TPA: 248.3 g (23.0 mol %) were charged, and acetic anhydride was charged in an amount of 1.03 times the moles of hydroxyl groups (moles) of all the monomers, and desorption was performed under the following conditions. Acetic acid polymerization was performed.

In a nitrogen gas atmosphere, the temperature was raised from room temperature to 150° C. over 1 hour and maintained at 150° C. for 60 minutes. Next, the temperature was raised to 350° C. over 7 hours while acetic acid, which was produced as a by-product, was distilled off, and then the pressure was reduced to 10 mmHg over 90 minutes. When a predetermined torque was exhibited, the polymerization reaction was terminated, the contents were taken out from the reactor, and pellets of liquid crystalline polyester (LCP-1) were obtained using a pulverizer. The amount of acetic acid distilled off during polymerization was almost the same as the theoretical value. The obtained pellets had a crystalline melting temperature (Tm) of 338° C. and a melt viscosity of 23 Pa·s.

[Synthesis Example 2 (LCP-2)]
POB: 314.2 g (35 mol %), BON6: 61.2 g (5 mol %), BP: 169.4 g (14 mol %) were placed in a 2 L reaction vessel equipped with a stirrer with a torque meter and a distillation tube. , HQ: 114.5 g (16 mol %) and TPA: 323.9 g (30 mol %) were charged, and acetic anhydride was charged in an amount of 1.03 times the amount of hydroxyl groups (mol) of all monomers, Deacetic acid polymerization was carried out under the following conditions.

Under a nitrogen gas atmosphere, the temperature was raised from room temperature to 145° C. over 1 hour, and the same temperature was maintained for 30 minutes. Next, the temperature was raised to 350° C. over 7.5 hours while acetic acid, which is a by-product, was distilled off, and then the pressure was reduced to 5 mmHg over 80 minutes. When a predetermined torque was exhibited, the polymerization reaction was terminated, the contents were taken out from the reaction vessel, and pellets of a liquid crystalline polyester resin (LCP-2) were obtained using a pulverizer. The amount of acetic acid distilled off during polymerization was almost the same as the theoretical value. The crystalline melting temperature (Tm) of the obtained pellets was 337°C.

The fluororesins and plate-like fillers used in the following examples and comparative examples are shown.
<Fluororesin>
FR1: Kitamura Co., Ltd., PTFE "KT-300M" (average particle size: 40 μm)
FR2: Kitamura Co., Ltd., PTFE "KT-400M" (average particle size: 33 μm)
FR3: Kitamura Co., Ltd., PTFE "KTL-610" (average particle size: 12 μm)
FR4: Daikin Industries, Ltd., PTFE "L5-F" (average particle size: 5 μm)
<Plate-shaped filler>
Talc: Nippon Talc Co., Ltd., "Rose K"
Mica: "AB-25S" manufactured by Yamaguchi Mica Co., Ltd.
Kaolin: "SB 100S" manufactured by Imerys Minerals Japan Co., Ltd.
<Granular filler>
Calcium carbonate: "KRS1" manufactured by Maruo Calcium Co., Ltd.

Examples 1-4 and Comparative Examples 1-8
The LCP synthesized in Synthesis Examples 1 and 2, the fluororesin and the filler were blended so that the content (parts by mass) shown in Table 1 was obtained, and a twin-screw extruder (Nippon Steel Co., Ltd. TEX- 30), melt-kneading was performed at 350° C. to obtain pellets of the liquid crystalline polyester resin composition. By the above methods, bending strength, bending elastic modulus, tensile elastic modulus, tensile elongation, high-temperature dent amount and dynamic friction coefficient were measured and evaluated. Table 1 shows the results.

As shown in Table 1, all of the liquid crystal polyester resin compositions of Examples 1 to 4 were excellent in mechanical properties and heat resistance while maintaining slidability.

On the other hand, as shown in Table 1, it was confirmed that the liquid crystal polyester resin compositions of Comparative Examples 1 to 8 were deteriorated in any of slidability, mechanical properties and heat resistance.

Claims (7)

Formulas (I)-(III)

[In the formula,
Ar ₁ and Ar ₂ each represent one or more divalent aromatic groups, and p, q and r are each the composition ratio (mol%) of each repeating unit in the liquid crystalline polyester. , satisfying the following conditions:
35≦p≦90,
5≤q≤30, and 5≤r≤30]
A liquid crystalline polyester containing a repeating unit represented by
A fluororesin having an average particle size of 25 μm or more;
A liquid crystal polyester resin composition containing a plate-like filler, wherein the content of the fluororesin is 1 to 30 parts by mass and the content of the plate-like filler is 5 to 80 parts by mass with respect to 100 parts by mass of the liquid crystal polyester. . Formula (II) and/or Formula (III) are represented by Ar ₁ and Ar ₂ , independently of each other, of Formulas (1)-(4)

2. The liquid crystalline polyester resin composition according to claim 1, comprising one or more repeating units that are aromatic groups selected from the group consisting of: 3. The liquid crystalline polyester resin composition according to claim 1, wherein the fluororesin is polytetrafluoroethylene. 4. The liquid crystalline polyester resin composition according to any one of claims 1 to 3, wherein the plate-like filler is one or more selected from the group consisting of talc, mica and kaolin. Claims 1 to 2, wherein the amount of depression is 4.0 μm or less when a load of 1000 mN is applied in the thickness direction of a plate-shaped test piece having a length of 10 mm, a width of 4.5 mm, and a thickness of 3.2 mm at 270 ° C. 5. The liquid crystal polyester resin composition according to any one of 4. A molded article composed of the liquid crystalline polyester resin composition according to any one of claims 1 to 5. The moldings are selected from the group consisting of instrument panels, door panels, door trims, middle boards, door ornaments, cover seat rear undertrays, truck covers, service hole covers, pillars, scuff plates, center consoles, cup holders and column covers. 7. A molded article according to claim 6, which is a part of one kind.