JP5407988B2 - Liquid crystalline resin composition and molded product thereof - Google Patents

Description

  The present invention relates to a liquid crystalline resin composition and a molded body thereof.

  The liquid crystalline resin forms a polydomain having a liquid crystal state without causing entanglement even in a molten state because the molecules are rigid, and during molding, molecular chains are remarkably oriented in the flow direction by shearing. Although it has the advantage of giving a molded body with high strength, this orientation makes it easy for the molded body to have anisotropy in mechanical, thermal and electrical properties, or the surface of the molded body is fibrous. Are easily peeled off, that is, easily fibrillated. For this reason, various techniques for relaxing the orientation during molding of the liquid crystalline resin within a range that does not significantly reduce the mechanical strength of the molded body have been studied. For example, Patent Document 1 discloses a predetermined fiber diameter for the liquid crystalline resin. A liquid crystalline resin composition is disclosed in which a predetermined amount of the glass fiber is blended, and the glass fiber has a predetermined fiber length distribution.

JP-A-6-240115

  In the conventional liquid crystalline resin composition, it has been difficult to suppress fibrillation even if the anisotropy of various physical properties of the obtained molded article can be reduced by relaxing the orientation during molding of the liquid crystalline resin. Then, the objective of this invention is providing the liquid crystalline resin composition which gives the molded object which is hard to fibrillate.

  In order to achieve the above object, the present invention provides a liquid crystalline resin composition comprising a liquid crystalline resin and aggregated particles formed by aggregation of calcium silicate plate crystals. Moreover, according to this invention, the molded object formed by melt-molding the said liquid crystalline resin composition is also provided.

  According to the liquid crystalline resin composition of the present invention, it is possible to obtain a molded body that is difficult to be fibrillated. Also, when acetic anhydride is used in the production of a liquid crystalline resin or an acetylated product is used as a raw material monomer, there is a problem that acetic acid remains in the liquid crystalline resin and acetic acid is generated from the molded product. However, the molded product obtained from the liquid crystalline resin composition of the present invention also has an advantage that acetic acid is hardly generated.

  The liquid crystal polymer used in the present invention is a polymer that exhibits optical anisotropy when melted and forms an anisotropic melt at a temperature of 500 ° C. or lower. This optical anisotropy can be confirmed by a normal polarization inspection method using an orthogonal polarizer. The liquid crystal polymer has a molecular chain that is elongated in shape, is flat, and has high rigidity along the long chain of the molecule (hereinafter, the molecular chain with high rigidity may be referred to as a “mesogen group”). . The liquid crystal polymer is a polymer having such a mesogenic group in one or both of the main chain and the side chain, but has a mesogenic group in the polymer main chain if a higher heat-resistant molded product is desired. Those are preferable for the liquid crystalline resin composition of the present invention.

  Specific examples of the liquid crystal polymer include liquid crystal polyester, liquid crystal polyester amide, liquid crystal polyester ether, liquid crystal polyester carbonate, liquid crystal polyester imide, and liquid crystal polyamide. Among these, a high-strength molded article can be obtained. Liquid crystal polyester, liquid crystal polyester amide or liquid crystal polyamide is preferred.

Specifically, the preferred liquid crystal polymer is preferably at least one liquid crystal polymer selected from the following (a) to (c).
(A): Liquid crystal polyester, liquid crystal polyester amide or liquid crystal polyamide comprising the structural unit (I) and / or the structural unit (II).
(B): Liquid crystal polyester or liquid crystal polyester amide comprising a structural unit selected from the structural unit (I) and the structural unit (II), the structural unit (III), and the structural unit (IV).
(C) a structural unit selected from the structural unit (I) and the structural unit (II), a structural unit (III), a structural unit (IV), a structural unit (V), and a structural unit selected from the structural unit (VI). Liquid crystalline polyester or liquid crystalline polyester amide comprising:

In the formula, Ar ¹ , Ar ² , Ar ⁵ and Ar ⁶ each independently represent a divalent aromatic group, and Ar ³ and Ar ⁴ are each independently selected from an aromatic group, an alicyclic group and an aliphatic group. Represents a divalent group. Note that some or all of the hydrogen atoms on the aromatic ring in the aromatic group may be substituted with a halogen atom, an alkyl group having 1 to 10 carbon atoms, an alkoxy group, or an aryl group having 6 to 10 carbon atoms. Good. Here, the alicyclic group means a group obtained by removing two hydrogen atoms from an alicyclic compound, and the aliphatic group means a group obtained by removing two hydrogen atoms from an aliphatic compound. .

In the above structural unit, the aromatic groups related to Ar ¹ , Ar ² , Ar ⁵ and Ar ⁶ include monocyclic aromatic groups such as benzene, naphthalene, biphenylene, diphenyl ether, diphenyl sulfone, diphenyl ketone, diphenyl sulfide, and diphenylmethane. Hydrogen atom bonded to the aromatic ring of the aromatic compound selected from the group consisting of a compound, a condensed ring aromatic compound, and an aromatic compound in which a plurality of aromatic rings are connected by a divalent linking group (including a single bond) , Preferably 2,2-diphenylpropane, 1,4-phenylene group, 1,3-phenylene group, 2,6-naphthalenediyl group and 4,4′-biphenylene. The liquid crystal polymer in which the aromatic group is a divalent aromatic group selected from a group and the aromatic group is such a group tends to be more excellent in mechanical strength. Preferred.

Ar ³ in the structural unit (III) and Ar ⁴ in the structural unit (IV) are saturated with 1 to 9 carbon atoms in addition to the aromatic group described for Ar ¹ , Ar ² , Ar ⁵ or Ar ^6. It is a group selected from a divalent aliphatic group and a divalent alicyclic group obtained by removing two hydrogen atoms from an aliphatic compound.

  The structural unit (I) is a structural unit derived from an aromatic hydroxycarboxylic acid, and examples of the aromatic hydroxycarboxylic acid include 4-hydroxybenzoic acid, 3-hydroxybenzoic acid, and 6-hydroxy-2-naphthoic acid. , 7-hydroxy-2-naphthoic acid, 6-hydroxy-1-naphthoic acid, 4′-hydroxybiphenyl-4-carboxylic acid, or part or all of hydrogen on the aromatic ring in these aromatic hydroxycarboxylic acids Is an aromatic hydroxycarboxylic acid substituted with an alkyl group, an alkoxy group or a halogen atom. In addition, as an alkyl group, a C1-C6 linear, branched or alicyclic alkyl group such as a methyl group, an ethyl group, a propyl group, an isopropyl group, a butyl group, a tert-butyl group, a hexyl group, or a cyclohexyl group. Is mentioned. Examples of the alkoxy group include linear, branched or alicyclic alkoxy groups such as a methoxy group, ethoxy group, propoxy group, isopropyloxy group, butoxy group, tert-butoxy group, hexyloxy group, and cyclohexyloxy group. Examples of the aryl group include a phenyl group and a naphthyl group. The halogen atom is selected from a fluorine atom, a chlorine atom, a bromine atom, and an iodine atom.

  The structural unit (II) is a structural unit derived from an aromatic aminocarboxylic acid, and examples of the aromatic aminocarboxylic acid include 4-aminobenzoic acid, 3-aminobenzoic acid, and 6-amino-2-naphthoic acid. Or an aromatic aminocarboxylic acid in which part or all of hydrogen on the aromatic ring in these aromatic aminocarboxylic acids is substituted with an alkyl group, an alkoxy group, an aryl group, or a halogen atom. Here, examples of the alkyl group, alkoxy group, aryl group, and halogen atom are the same as those exemplified for the aromatic hydroxycarboxylic acid.

  The structural unit (III) is a group derived from an aromatic dicarboxylic acid or an aliphatic dicarboxylic acid. Examples of the aromatic dicarboxylic acid include terephthalic acid, 4,4′-diphenyldicarboxylic acid, 4,4 ″- Triphenyl dicarboxylic acid, 2,6-naphthalenedicarboxylic acid, diphenyl ether-4,4′-dicarboxylic acid, isophthalic acid, diphenyl ether-3,3′-dicarboxylic acid, or hydrogen on the aromatic ring in these aromatic dicarboxylic acids Aromatic dicarboxylic acids partially or wholly substituted with alkyl groups, alkoxy groups, aryl groups, and halogen atoms can be mentioned. Examples of the aliphatic dicarboxylic acids include malonic acid, succinic acid, adipic acid, trans-1 , 4-cyclohexanedicarboxylic acid, cis-1,4-cyclohexanedicarboxylic acid, 1,3-cyclohex Alicyclic dicarboxylic acids such as dicarboxylic acids; and trans-1,4- (1-methyl) cyclohexanedicarboxylic acid, cis-1,4-cyclohexanedicarboxylic acid or aliphatic groups or fats in these aliphatic dicarboxylic acids Examples include aliphatic dicarboxylic acids in which part or all of the hydrogen atoms in the ring group are substituted with alkyl groups, alkoxy groups, aryl groups, or halogen atoms. Examples of the alkyl group, alkoxy group, aryl group, and halogen atom are the same as those exemplified for the aromatic hydroxycarboxylic acid.

  The structural unit (IV) is a group derived from an aromatic diol or an aliphatic diol, and examples of the aromatic diol include hydroquinone, resorcin, naphthalene-2,6-diol, 4,4′-biphenylenediol, 3 , 3'-biphenylenediol, 4,4'-dihydroxydiphenyl ether, 4,4'-dihydroxydiphenylsulfone, or a part or all of hydrogen on the aromatic ring in these aromatic diols is an alkyl group, an alkoxy group, an aryl group And aromatic diols substituted with halogen atoms. Examples of the aliphatic diol include ethylene glycol, propylene glycol, butylene diol, neopentyl glycol, 1,6-hexanediol, and trans-1,4-cyclohexanediol. Cis-1,4-cyclohexane All, trans-1,4-cyclohexanedimethanol, cis-1,4-cyclohexanedimethanol, trans-1,3-cyclohexanediol, cis-1,2-cyclohexanediol, trans-1,3-cyclohexanedimethanol or Examples thereof include aliphatic diols in which part or all of the hydrogen atoms of the aliphatic group or alicyclic group in these aliphatic diols are substituted with alkyl groups, alkoxy groups, aryl groups, or halogen atoms. Examples of the alkyl group, alkoxy group, and halogen atom are the same as those exemplified for the aromatic hydroxycarboxylic acid.

  The structural unit (V) is a structural unit derived from an aromatic hydroxyamine. Examples of the aromatic hydroxyamine include 4-aminophenol, 3-aminophenol, 4-amino-1-naphthol, 4-amino- Examples include 4′-hydroxydiphenyl or aromatic hydroxyamines in which part or all of hydrogen on the aromatic ring in these aromatic hydroxyamines is substituted with an alkyl group, an alkoxy group, an aryl group, or a halogen atom. Here, examples of the alkyl group, alkoxy group, aryl group, and halogen atom are the same as those exemplified for the aromatic hydroxycarboxylic acid.

  The structural unit (VI) is a structural unit derived from an aromatic diamine. Examples of the aromatic diamine include 1,4-phenylenediamine, 1,3-phenylenediamine, 4,4′-diaminophenyl sulfide (thiodianiline). ), 4,4′-diaminodiphenyl sulfone, 4,4′-diaminodiphenyl ether (oxydianiline), or a part or all of hydrogen on the aromatic ring in these aromatic diamines is an alkyl group, an alkoxy group, Examples thereof include an aryl group, an aromatic aminocarboxylic acid substituted with a halogen atom, and an aromatic diamine obtained by substituting a hydrogen atom bonded to the primary amino group of the aromatic diamine exemplified above with an alkyl group. Here, examples of the alkyl group, alkoxy group, aryl group, and halogen atom are the same as those exemplified for the aromatic hydroxycarboxylic acid.

In the preferable liquid crystal polymer, (b) or (c) may have an aliphatic group in the structural unit (III) and the structural unit (IV). The amount is selected within a range where the liquid crystal polymer can exhibit liquid crystallinity, and further selected within a range where the heat resistance of the liquid crystal polymer is not significantly impaired. In the liquid crystal polymer applied to the present invention, when the total of Ar ^{1 to} Ar ⁶ is 100 mol%, the total of divalent aromatic groups is preferably 60 mol% or more, and is 75 mol% or more. More preferably, it is more preferably 90 mol% or more, and a wholly aromatic liquid crystal polymer in which the total of divalent aromatic groups is 100 mol% is particularly preferable.

  Among the preferred wholly aromatic liquid crystal polymers, the liquid crystal polyester (a) or the liquid crystal polyester (b) is preferable, and the liquid crystal polyester (b) is particularly preferable. Among the liquid crystalline polyesters of (b), structural units derived from the following (I-1) and / or (I-2) aromatic hydroxycarboxylic acids, and the following (III-1) and (III- 2) and a structural unit derived from at least one aromatic dicarboxylic acid selected from the group consisting of (III-3), and the following (IV-1), (IV-2), (IV-3) and The liquid crystalline polyester comprising a structural unit derived from at least one aromatic diol selected from the group consisting of (IV-4) has high properties such as moldability, heat resistance, high mechanical strength and flame retardancy. There exists an advantage that the molded object which becomes a standard is easy to be obtained.

  As the method for producing the liquid crystal polymer, aromatic hydroxycarboxylic acid and / or aromatic aminocarboxylic acid is used as a raw material monomer in (a), and aromatic hydroxycarboxylic acid and / or aromatic is used in (b). An aromatic aminocarboxylic acid, an aromatic dicarboxylic acid and / or an aliphatic dicarboxylic acid, an aromatic diol and / or an aliphatic diol as raw material monomers, and in (c), the aromatic carboxylic acid and / or aromatic A raw material monomer is an aminocarboxylic acid, an aromatic dicarboxylic acid and / or an aliphatic dicarboxylic acid, and at least one compound selected from the group consisting of an aromatic diol, an aliphatic diol, an aromatic hydroxyamine, and an aromatic diamine. A liquid crystal polymer can be produced by polymerizing these raw material monomers by a known polymerization method. In the liquid crystal polyester (b) which is a liquid crystal polymer which is a more preferred liquid crystal polymer, liquid crystal is obtained by polymerization using aromatic hydroxycarboxylic acid, aromatic dicarboxylic acid and aromatic diol as raw material monomers. Polyester can be obtained.

  As described above, in order to produce a liquid crystal polymer, the raw material monomers shown above may be directly polymerized. However, in order to facilitate the polymerization, a part of the raw material monomers may be converted into ester-forming derivatives, Polymerization is preferably performed after conversion to an amide-forming derivative (hereinafter, sometimes collectively referred to as an ester / amide-forming derivative). The ester / amide-forming derivative means a compound having a group that promotes an ester formation reaction or an amide formation reaction. Specifically, a carboxyl group in a monomer molecule is represented by a haloformyl group, an acid anhydride, or the like. And ester / amide-forming derivatives converted into esters, phenolic hydroxyl groups and phenolic amino groups in the monomer molecules as ester groups and amide groups, respectively.

  Examples of a method for producing a liquid crystal polyester (b) by converting a part of the raw material monomer into an ester / amide-forming derivative and performing polymerization include the method described in JP-A-2002-146003. . That is, first, an acylated product obtained by converting an aromatic hydroxycarboxylic acid and a phenolic hydroxyl group of an aromatic diol into an acyl group using an acid anhydride, preferably acetic anhydride, is produced. Next, the acyl group of the acylated product thus obtained and the carboxyl group of the acylated aromatic hydroxycarboxylic acid and aromatic dicarboxylic acid are subjected to deacetic acid polycondensation so as to cause transesterification, whereby a liquid crystal polyester is obtained. Produces. Such deacetic acid polycondensation can be carried out by melt polymerization under conditions of a reaction temperature of 150 to 400 ° C. and a reaction time of 0.5 to 8 hours. In the melt polymerization, a liquid crystal polyester having a relatively low molecular weight (hereinafter referred to as “prepolymer”) is obtained. In order to further improve the properties of the liquid crystalline polyester itself, it is preferable to further increase the molecular weight of the prepolymer, and it is preferable to perform solid-phase polymerization for the increase in the molecular weight. The solid phase polymerization is a polymerization method in which the prepolymer is pulverized into a powder and the obtained powdered prepolymer is heated in a solid state. When such solid phase polymerization is used, the polymerization proceeds further, and the high molecular weight of the liquid crystal polyester can be achieved.

  The liquid crystalline resin composition of the present invention comprises the liquid crystalline resin as described above and aggregated particles formed by aggregation of calcium silicate plate crystals. Thus, by blending the predetermined aggregated particles with the liquid crystalline resin, it is possible to obtain a liquid crystalline resin composition that gives a molded body that is hardly fibrillated and hardly generates acetic acid.

  The average particle diameter of the plate crystal is usually 0.05 μm to 50 μm, preferably 0.1 to 30 μm. The average particle size referred to here is a number average particle size measured by a microscopic method. Typically, a plate-like crystal is dispersed in methanol to prepare a dispersion, and the dispersion is used as a slide glass. After spreading on top and evaporating methanol, a scanning electron microscope is used to take a micrograph at a measurement magnification of 2000 times, from which the particle size of about 100 plate crystals is measured, and these are number averaged It is the value.

Examples of the plate-like crystals include crystals of tobermorite (chemical formula: Ca ₅ Si ₆ O ₁₆ (OH) ₂ .4H ₂ O), crystals of wollastonite (chemical formula: CaO · SiO ₂ ), and zonotlite (chemical formula: CaO crystalline of SiO ₂ · H ₂ O) and the like.

  The shape of the aggregated particles may be spherical or substantially spherical, may be irregular, or may have irregularities on a part of its surface. The aggregated particles preferably have an average particle size of 1 to 100 μm, more preferably 5 to 50 μm, in terms of improving the miscibility when melt-kneaded with the liquid crystalline resin. More preferably, it is 10-40 micrometers. After producing aggregated particles by aggregating plate crystals, if the obtained aggregated particles do not satisfy such an average particle size, it is adjusted to the desired average particle size by classification through an appropriate classification operation. You can also In addition, the average particle diameter here is a volume average particle diameter measured by a laser diffraction method.

  Examples of the commercial product of the aggregated particles include “Tobermorite Powder TJ” (average particle size 17 μm) and “Tobermorite Powder TK” (average particle size 24 μm) manufactured by Nippon Insulation Co., Ltd. Such commercially available agglomerated particles are commercially available for building materials such as refractory materials, heat insulating materials, and design materials. By using such commercially available aggregated particles, the fibrillation of a molded product using a liquid crystalline resin can be suppressed and the amount of acetic acid generated from the molded product can be reduced for the first time by the present inventors' investigation. It has been found.

  The content of the aggregated particles in the liquid crystalline resin composition of the present invention is usually 0.1 to 150 parts by weight, preferably 0.5 to 67 parts by weight, more preferably 1 to 100 parts by weight of the liquid crystalline resin. ~ 25 parts by weight. If the content of the aggregated particles is too small, fibrillation of the resulting molded product may not be sufficiently suppressed. In addition, the effect of reducing the amount of acetic acid generated is reduced. On the other hand, if the content of the agglomerated particles is too large, the moldability of the liquid crystalline resin composition tends to be deteriorated, and the mechanical strength of the resulting molded article tends to be lowered and become brittle.

  The liquid crystalline resin composition of the present invention can be prepared by various conventional methods. For example, the liquid crystalline resin composition of the present invention can be obtained by mixing the liquid crystalline resin and the aggregated particles using a Henschel mixer or a tumbler. Further, the liquid crystalline resin composition of the present invention is formed into a pellet (composition pellet) by previously melting the liquid crystalline resin using an extruder and then adding the aggregated particles and melt-kneading them. It can also be obtained. Moreover, you may combine such a method. That is, the liquid crystalline resin and the agglomerated particles are mixed in advance using a Henschel mixer, a tumbler, or the like to obtain a mixture, and the mixture is further melt-kneaded using an extruder to obtain the liquid crystalline resin composition of the present invention. The product can also be obtained in the form of pellets (composition pellets). In this way, the liquid crystalline resin composition of the present invention can be obtained. As a method for producing the liquid crystalline resin composition, it is also possible to obtain the composition pellets using an extruder, which is used for subsequent molding. This is preferable because it is excellent in handling. The extruder is more preferably a biaxial kneading extruder.

  For the production of the composition pellets, the entire liquid crystalline resin to be used can be heated and melted in advance, and then the entire aggregated particles to be used for this can be melt-kneaded. Preferably, a part of the liquid crystalline resin is used. And agglomerated particles to obtain a mixture, and a step of melt kneading the remainder of the liquid crystalline resin in the mixture, and the liquid crystalline resin composition for obtaining composition pellets by the melt kneading step A production method is particularly preferred.

  The liquid crystalline resin composition of the present invention contains components other than the liquid crystalline resin and the aggregated particles in order to improve other properties such as mechanical strength within a range that does not significantly impair the object of the present invention. It may be. Examples of such components include fibrous fillers, plate-like fillers, spherical fillers, powdery fillers, irregularly shaped fillers, whisker fillers, coloring components, lubricants, various surfactants, antioxidants and thermal stabilizers. Various other stabilizers, ultraviolet absorbers, antistatic agents and the like can be used. Examples of the fibrous filler include glass fiber, PAN-based carbon fiber, pitch-based carbon fiber, silica-alumina fiber, silica fiber, and alumina fiber. Examples of the plate filler include talc, mica, and graphite. Examples of the spherical filler include glass beads and glass balloons. Examples of the powder filler include calcium carbonate, dolomite, barium clay sulfate, titanium oxide, carbon black, conductive carbon, and fine silica. Examples of the irregularly shaped filler include glass flakes and irregularly shaped glass fibers. These components may be used alone or in combination of two or more. The amount used is appropriately adjusted depending on the type and combination, but is generally 250 parts by weight or less in total, preferably 150 parts by weight or less, more preferably 100 parts by weight or less, based on 100 parts by weight of the liquid crystalline resin. Preferably it is 67 weight part or less. For example, when a fibrous filler is included in the liquid crystalline resin composition to improve mechanical strength, the content of the fibrous filler is usually 5 to 150 parts by weight, preferably 10 parts per 100 parts by weight of the liquid crystalline resin. -100 parts by weight, more preferably 15-50 parts by weight.

  The liquid crystalline resin composition of the present invention has a remarkable effect of preventing fibrillation very well in conventionally known melt molding, preferably injection molding. It can also be applied to other moldings in the melt molding, that is, extrusion molding, compression molding, blow molding, vacuum molding, film forming using T-die, film forming such as inflation molding, and melt spinning. is there.

Among these melt moldings, injection molding is preferable in that molded bodies having various shapes can be produced and high productivity is easy. In the injection molding, when the liquid crystalline resin composition of the present invention is obtained as the above-described composition pellets, typically, first, the flow start temperature FT (° C.) of the composition pellets is obtained. Here, the flow start temperature represents the temperature at which the composition pellets melt in the plasticizer of the injection molding machine, and is usually the flow start temperature of the liquid crystalline resin composition itself. The flow starting temperature is a capillary rheometer having a nozzle with an inner diameter of 1 mm and a length of 10 mm, and the heated melt is heated at a rate of 4 ° C./min under a load of 9.81 MPa (100 kgf / cm ² ). This is a temperature at which the melt viscosity is 4800 Pa · s (48000 poise) when the nozzle is pushed out while raising the temperature. In the technical field of liquid crystal polymer, such flow initiation temperature is well known as an index representing the molecular weight of the liquid crystal polymer (edited by Naoyuki Koide, “Liquid Crystalline Polymer Synthesis / Formation / Application—”, (See pages 95-105, CMC, issued June 5, 1987). In the present invention, a flow characteristic evaluation device “Flow Tester CFT-500D” manufactured by Shimadzu Corporation is used as a device for measuring the flow start temperature.

  As a suitable injection molding, the composition pellet is melted at a temperature (resin melting temperature) of [FT] ° C. or more and [FT + 100] ° C. or less with respect to the flow start temperature FT (° C.) of the composition pellet. And the melt is injected into a mold set at a temperature of 0 ° C. or higher. The composition pellets are preferably sufficiently dried before being subjected to injection molding. If the resin melting temperature is lower than FT (° C.), the composition pellets cannot be sufficiently melted, and the fluidity of the melt is lowered. Is not preferable, and the transferability to the mold surface tends to be low and the surface of the molded body tends to be rough. On the other hand, when the resin melting temperature is higher than [FT + 100] ° C., the liquid crystalline resin in the composition pellets in the molding machine is decomposed, and the resulting molded article has a bulging appearance abnormality or the liquid crystal This is not preferable because the decomposition product of the functional resin is gasified to easily cause degassing. Further, if the resin melting temperature is higher than [FT + 100] ° C., when the mold is opened after the injection molding and the molded body is taken out, there is a tendency that the molten resin flows out from the nozzle. Since productivity itself falls, it is not preferable. Considering the stability and moldability (productivity) of the molded product, the resin melting temperature is preferably [FT + 10] ° C. or more and [FT + 80] ° C. or less, and more preferably [FT + 15] or more and [FT + 60] ° C. or less. Is more preferable.

  In addition, as described above, the mold temperature is usually set to 0 ° C. or higher. However, the mold temperature takes into consideration the appearance, dimensions, mechanical properties, and productivity such as workability and molding cycle of the obtained molded body. To be determined. In consideration of this requirement, the mold temperature is preferably 40 ° C. or higher. When the mold temperature is lower than 40 ° C., it is difficult to control the mold temperature in continuous molding, and the temperature variation may adversely affect the molded body. More preferably, the mold temperature is 70 ° C. or higher. If the mold temperature is lower than 70 ° C., the surface smoothness of the resulting molded product may be impaired. From the viewpoint of improving surface smoothness, the higher the mold temperature is, the more advantageous.However, if the mold temperature is too high, the cooling effect is reduced and the time required for the cooling process is increased. This is not preferable because problems such as a deformation of the molded body due to a decrease in moldability occur. Furthermore, if the mold temperature is raised too much, the engagement between the molds becomes worse, and the risk of breakage when the mold is opened and closed tends to increase. In order to prevent decomposition of the liquid crystalline resin contained in the composition pellets, the upper limit of the mold temperature is also preferably optimized depending on the type of composition pellets to be applied. When the liquid crystalline resin to be used is a wholly aromatic polyester, the mold temperature is preferably 70 ° C. or higher and 220 ° C. or lower, and more preferably 130 ° C. or higher and 200 ° C. or lower.

  According to the examination results of the present inventors, it has been found that the problem of surface peeling of the injection-molded product is greatly improved by filling the liquid crystalline resin with the aggregated particles. This is presumed to be due to the following reasons.

  As described above, when the molten liquid crystalline resin is injection-molded, the molten liquid crystalline resin undergoes shearing on the mold surface, and is thus largely oriented (that is, the molecular chain direction is aligned). In the liquid crystalline resin, the orientation of the molecular chain itself is very strong. In addition, the liquid crystalline resin has a feature that the cooling and solidification rate is fast, but the relaxation time is long. For this reason, the liquid crystal orientation in a molded object becomes very strong.

  In a molded body of a liquid crystalline resin, a specific layer called a skin layer is usually easily formed on the surface. In this skin layer, the liquid crystalline resin is particularly strongly oriented. For this reason, in the conventional liquid crystalline resin molded body, even if it is rubbed weakly, surface peeling may occur and fibrous fibrils may become fluffy. The surface peeling can be visually observed by repeating, for example, a tape peeling test (that is, an operation of putting a tape on the surface of the molded body and peeling it off). Such surface peeling has heretofore been one of the drawbacks of injection molded articles using a liquid crystalline resin composition.

  On the other hand, in the molded body of the present invention, the occurrence of such surface peeling is greatly suppressed. The reason why the peel resistance is improved by the present invention is considered to be because the aggregated particles are exposed on the surface of the molded body, so that a so-called anchor effect occurs and the surface strength increases.

  Further, when the liquid crystalline resin used in the present invention is a liquid crystalline polyester, acetic acid resulting from the production method remains in the resin. In the molded body using this liquid crystalline polyester, acetic acid remaining from the resin is generated.

  On the other hand, in the molded article of the present invention, the amount of acetic acid generated from the molded article can be suppressed. The reason for this is presumed that acetic acid remaining from the aggregated particles is collected and encapsulated in the molded body, whereby acetic acid generated from the molded body can be suppressed.

  The liquid crystalline resin composition of the present invention may contain one or more thermoplastic resin components other than the liquid crystalline resin as long as the intended purpose of the present invention is not impaired. Further, one or more thermosetting resins such as a phenol resin, an epoxy resin, and a polyimide resin may be included as long as the purpose of the present invention is not impaired.

<Use of molded body>
The liquid crystalline resin composition of the present invention is suitable as a molding material for producing electric / electronic parts and optical parts. Examples of such electrical / electronic components and optical components include connectors, sockets, relay components, coil bobbins, optical pickups, oscillators, printed wiring boards, circuit boards, semiconductor device packages, computer-related components, camera barrels, optical Sensor housing, compact camera module housing (eg, package or lens barrel), projector optical engine components, semiconductor manufacturing process related parts (eg, IC tray or wafer carrier), home appliance parts (eg, VTRs, TVs, irons, air conditioners, stereos, vacuum cleaners, refrigerators, rice cookers, lighting fixtures, etc.), lighting fixtures (eg, lamp reflectors, lamp holders, etc.), acoustic products (eg, compact discs, lasers) Disk (registered trademark), Speaker components, etc.), parts of the communication device (e.g., an optical cable ferrule, telephone parts, can be mentioned facsimile parts, modem components, etc.) and the like.

  In addition, other applications such as related parts of copiers and printing machines (for example, separation claws, heater holders, etc.), machine parts (for example, impellers, fan gears, gears, bearings, motor parts and cases), automobile parts ( For example, automotive mechanical parts, engine parts, engine room parts, electrical parts, interior parts, etc.), cooking utensils (eg microwave cooking pans, heat-resistant dishes, etc.), building materials or civil engineering building materials (eg flooring or Insulating and soundproofing materials such as wall materials, supporting materials such as beams and columns, roofing materials, etc.) parts for aircraft, spacecraft and space equipment, radiation facility members such as nuclear reactors, marine facility members, cleaning jigs, Can be used for optical equipment parts, valves, pipes, nozzles, filters, membranes, medical equipment parts and medical materials, sensor parts, sanitary equipment, sports equipment, leisure equipment Kill.

  Thus, the resin molding of this invention can be used for various uses. Since the present invention is excellent in resistance to surface peeling, it is easy to cause failure of particles (dust) from the molded body, such as contact parts (switches, relays, etc.), optical sensor parts, camera parts, Particularly preferred.

Examples 1-3, Comparative Example 1
[Manufacture of liquid crystalline resin]
In a reactor equipped with a stirrer, a torque meter, a nitrogen gas inlet tube, a thermometer and a reflux condenser, 994.5 g (7.2 mol) of p-hydroxybenzoic acid, 446.9 g of 4,4′-dihydroxybiphenyl ( 2.4 mol), 299.0 g (1.8 mol) of terephthalic acid, 99.7 g (0.6 mol) of isophthalic acid, 1347.6 g (13.2 mol) of acetic anhydride and 0.194 g of 1-methylimidazole. Prepared. And it stirred for 15 minutes at room temperature, and the inside of a reactor was fully substituted with nitrogen gas, and also it heated up, stirring. And when the temperature in a reactor became 145 degreeC, it stirred for 1 hour, hold | maintaining this temperature. Thereafter, while distilling off distilling by-product acetic acid and unreacted acetic anhydride, the temperature was raised to 320 ° C. over 2 hours and 50 minutes, and the reaction was continued until a torque increase was observed. Thereby, a prepolymer was obtained. The flow initiation temperature of such prepolymer was 261 ° C.

  Next, this prepolymer was cooled to room temperature and further pulverized with a coarse pulverizer to obtain liquid crystal polyester powder (particle diameter of about 0.1 mm to about 1 mm). Then, the temperature is raised from room temperature to 250 ° C. over 1 hour in a nitrogen atmosphere, and further, the temperature is raised from 250 ° C. to 285 ° C. over 5 hours, and then maintained at 285 ° C. for 3 hours, thereby solid phase polymerization. Went. The flow starting temperature of the liquid crystal polyester thus obtained was 327 ° C.

[Agglomerated particles]
As the aggregated particles (1), “Tobermorite Powder TJ” manufactured by Nippon Insulation Co., Ltd. (packing density (JIS K 1464) 0.129 g / cc, average particle size (laser diffraction method) 17 μm, specific surface area (BET method) 55 m ² / g, oil absorption (JIS K 5101) 441 ml / 100 g) was used. Further, as the aggregated particles (2), “Tobermorite Powder TK” manufactured by Nippon Insulation Co., Ltd. (packing density (JIS K 1464) 0.136 g / cc, average particle size (laser diffraction method) 24 μm, specific surface area (BET Method) 56 m ² / g, oil absorption (JIS K 5101) 624 ml / 100 g) was used.

[Production of liquid crystalline resin composition]
Aggregated particles of the type and amount shown in Table 1 with respect to 100 parts by weight of the liquid crystalline resin, the amount of glass fiber shown in Table 1 (“EFH75-01” (average fiber length 75 μm) manufactured by Central Glass Co., Ltd.) and Carbon black ("Carbon Black CB # 45" manufactured by Mitsubishi Chemical Corporation) (1.4 parts by weight) was blended, and a cylinder was used using a twin screw extruder ("PCM-30" manufactured by Ikekai Tekko Co., Ltd.). Granulation was performed at a temperature of 350 ° C. to obtain pellets of the liquid crystalline resin composition.

[Evaluation of peel resistance]
After the pellets of the liquid crystalline resin composition are dried, using an injection molding machine (“PS40E-5ASE” manufactured by Nissei Plastic Industry Co., Ltd.), a plate-shaped molded product having an outer dimension of 64 × 64 × 1 mm is used. Molded. The operation of applying a tape (“Cellotape (registered trademark) CT-18” manufactured by Nichiban Co., Ltd.) over the entire surface of the molded article and then quickly peeling it off was repeated 30 times. In that case, the direction which sticks a tape was made into both directions of MD (flow direction at the time of shaping | molding) and TD (direction perpendicular | vertical to MD direction). After this operation, whether or not surface peeling (that is, fibrils) occurred in the molded product was visually observed, and the results are shown in Table 1.

[Evaluation of acetic acid generation]
The pellets of the liquid crystalline resin composition were dried and then molded into 0.8 mmt No. 6 dumbbell-shaped test pieces using an injection molding machine (“PS40E-5ASE” manufactured by Nissei Plastic Industry Co., Ltd.). The test piece was cut into a width of about 5 mm, purged with nitrogen, sealed in a vial, and then aged at 120 ° C. for 12 hours. About the gas in this vial bottle, the acetic acid density | concentration was measured with the gas chromatography ("GC-15A" by Shimadzu Corporation Corp.) by gas chromatography (head space method), and the result was shown in Table 1. .

Claims (6)

  A liquid crystalline resin composition comprising a liquid crystalline resin and aggregated particles formed by aggregation of calcium silicate plate crystals.   The liquid crystalline resin composition according to claim 1, wherein the plate crystal is a tobermorite crystal.   3. The liquid crystalline resin composition according to claim 1, wherein a content of the aggregated particles is 1 to 25 parts by weight with respect to 100 parts by weight of the liquid crystalline resin.   Furthermore, the liquid crystalline resin composition in any one of Claims 1-3 containing a fibrous filler.   The liquid crystalline resin composition according to claim 1 or 2, wherein a content of the fibrous filler is 15 to 50 parts by weight with respect to 100 parts by weight of the liquid crystalline resin.   The molded object formed by melt-molding the liquid crystalline resin composition in any one of Claims 1-5.