JP6843675B2 - Liquid crystal polyester composition and molded article - Google Patents

Description

The present invention relates to liquid crystal polyester compositions and molded articles.

Liquid crystal polyester has excellent moldability and high heat resistance. Liquid crystal polyester is used for electronic components such as connectors, relays, and bobbins by taking advantage of these characteristics. In recent years, electronic components have become highly integrated, miniaturized, thinned, and reduced in height. Among them, connector components have a remarkable tendency to be miniaturized and thinned.

Typical examples of such a connector include a board-to-board (B to B) connector and a flexible printed circuit board (FPC) connector. B to B connectors are used to join printed wiring boards together. The FPC connector is used to connect the FPC to a flexible flat cable (FFC).

Examples of B to B connectors and FPC connectors include those in which the pitch between the metal terminals of the connector is 0.35 mm or less. Further, the thickness dimension (so-called stacking height) in the state where the connector is fitted may be 0.6 mmt or less. In order to manufacture such a thin-walled connector, a material having excellent fluidity has been required.

In addition, as the thickness of the connector has been reduced, the warp that is so small that it can be ignored has become more apparent in the past.

Therefore, the molding material of a thin-walled connector represented by a B to B connector or an FPC connector is required to have excellent fluidity and reduce the warp of the molded body.

In response to such a requirement, Patent Document 1 discloses a liquid crystal polyester resin composition having good low warpage and excellent fluidity even in an ultrathin-walled molded product. The liquid crystal polyester resin composition disclosed in Patent Document 1 includes a liquid crystal polyester resin and fine glass flakes. The liquid crystal polyester resin composition disclosed in Patent Document 1 uses fine glass flakes having a number average particle diameter of 5 to 50 μm and an aspect ratio of 100 or less.

Japanese Unexamined Patent Publication No. 2011-074301

However, when an attempt is made to produce a small and thin-walled molded product using the liquid crystal polyester resin composition disclosed in Patent Document 1, short shots may occur and a desired shape may not be obtained. In addition, the molded product obtained by using this resin composition may be warped. From the above, there has been a demand for a liquid crystal polyester composition capable of stably producing a molded product and producing a molded product having less warpage.

The present invention has been made in view of such circumstances, and is a liquid crystal polyester composition and a molded product capable of stably producing a molded product even in a small and thin-walled molded product and producing a molded product with less warpage. The purpose is to provide.

In order to solve the above problems, one aspect of the present invention includes 5 parts by volume or more and 80 parts by volume or less of glass flakes with respect to 100 parts by mass of liquid crystal polyester, and the thickness of the glass flakes is 0.1 μm or more and 1.0 μm or less. The volume average particle size of the glass flakes measured by the laser diffraction method is 23 μm or more and 38 μm or less, and the glass flakes contain a large particle size component having a particle size of 100 μm or more and 400 μm or less and occupy 100% by volume of the glass flakes. Provided is a liquid crystal polyester composition having a large particle size component ratio of 0.1% by volume or more and 2.3% by volume or less.

In one aspect of the present invention, the ratio of the large particle size component to 100% by volume of the glass flakes may be 0.1% by volume or more and less than 1.0% by volume.

One aspect of the present invention provides a molded product using the above liquid crystal polyester composition as a forming material.

According to one aspect of the present invention, there is provided a liquid crystal polyester composition and a molded product capable of stably producing a molded product even in a small and thin-walled molded product and producing a molded product having less warpage.

The schematic perspective view which shows an example of the connector for FPC. Schematic cross-sectional view of the extruder used in the Examples.

<Liquid crystal polyester composition>
The liquid crystal polyester composition of the present embodiment contains a liquid crystal polyester and glass flakes.

[Liquid crystal polyester]
The liquid crystal polyester is a liquid crystal polyester that exhibits liquid crystal properties in a molten state, and is preferably melted at a temperature of 450 ° C. or lower. The liquid crystal polyester may be a liquid crystal polyester amide, a liquid crystal polyester ether, a liquid crystal polyester carbonate, or a liquid crystal polyester imide. The liquid crystal polyester is preferably a total aromatic liquid crystal polyester using only an aromatic compound as a raw material monomer.

As a typical example of liquid crystal polyester, at least one compound selected from the group consisting of aromatic hydroxycarboxylic acid, aromatic dicarboxylic acid, aromatic diol, aromatic hydroxyamine and aromatic diamine is polymerized (hypercondensation). ), A product obtained by polymerizing multiple types of aromatic hydroxycarboxylic acids, and at least one compound selected from the group consisting of aromatic dicarboxylic acids and aromatic diols, aromatic hydroxyamines and aromatic diamines. Examples thereof include those obtained by polymerizing the above, and those obtained by polymerizing a polyester such as polyethylene terephthalate and an aromatic hydroxycarboxylic acid. Here, the aromatic hydroxycarboxylic acid, the aromatic dicarboxylic acid, the aromatic diol, the aromatic hydroxyamine, and the aromatic diamine are independently used in place of a part or all of them, and a polymerizable derivative thereof is used. May be good.

Examples of polymerizable derivatives of compounds having a carboxyl group, such as aromatic hydroxycarboxylic acid and aromatic dicarboxylic acid, are those obtained by converting a carboxyl group into an alkoxycarbonyl group or an aryloxycarbonyl group (ester), and a carboxyl. Examples thereof include those obtained by converting a group into a haloformyl group (acid halide) and those obtained by converting a carboxyl group into an acyloxycarbonyl group (acid anhydride). Examples of polymerizable derivatives of compounds having a hydroxyl group, such as aromatic hydroxycarboxylic acids, aromatic diols and aromatic hydroxyamines, are those obtained by acylating a hydroxyl group and converting it to an acyloxyl group (acylated product). ). Examples of polymerizable derivatives of compounds having an amino group, such as aromatic hydroxyamines and aromatic diamines, include those obtained by acylating an amino group and converting it into an acylamino group (acylated product).

The liquid crystal polyester preferably has a repeating unit represented by the following formula (1) (hereinafter, may be referred to as “repetition unit (1)”), and the repeating unit (1) and the following formula (2) are used. A repeating unit represented (hereinafter, may be referred to as a “repeating unit (2)”) and a repeating unit represented by the following formula (3) (hereinafter, may be referred to as a “repeating unit (3)”). It is more preferable to have.

（Ａｒ^１は、フェニレン基、ナフチレン基又はビフェニリレン基を表す。Ａｒ^２及びＡｒ^３は、それぞれ独立に、フェニレン基、ナフチレン基、ビフェニリレン基又は下記式（４）で表される基を表す。Ｘ及びＹは、それぞれ独立に、酸素原子又はイミノ基（−ＮＨ−）を表す。Ａｒ^１、Ａｒ^２又はＡｒ^３で表される前記基にある水素原子は、それぞれ独立に、ハロゲン原子、アルキル基又はアリール基で置換されていてもよい。）

(Ar ¹ represents a phenylene group, a naphthylene group or a biphenylylene group. ^{Ar 2} and Ar ³ independently represent a phenylene group, a naphthylene group, a biphenylylene group or a group represented by the following formula (4). And Y each independently represent an oxygen atom or an imino group (-NH-). The ^{hydrogen atom in the group represented by Ar 1} , Ar ² or Ar ³ independently represents a halogen atom or an alkyl group, respectively. Alternatively, it may be substituted with an aryl group.)

（Ａｒ^４及びＡｒ^５は、それぞれ独立に、フェニレン基又はナフチレン基を表す。Ｚは、酸素原子、硫黄原子、カルボニル基、スルホニル基又はアルキリデン基を表す。）

(Ar ⁴ and Ar ⁵ independently represent a phenylene group or a naphthylene group. Z represents an oxygen atom, a sulfur atom, a carbonyl group, a sulfonyl group or an alkylidene group.)

Examples of the halogen atom include a fluorine atom, a chlorine atom, a bromine atom and an iodine atom. Examples of the alkyl group include methyl group, ethyl group, n-propyl group, isopropyl group, n-butyl group, isobutyl group, s-butyl group, t-butyl group, n-hexyl group and 2-ethylhexyl group. Examples thereof include an n-octyl group and an n-decyl group, which usually have 1 to 10 carbon atoms. Examples of the aryl group include a phenyl group, an o-tolyl group, an m-tolyl group, a p-tolyl group, a 1-naphthyl group and a 2-naphthyl group, which usually have 6 to 20 carbon atoms. .. When the hydrogen atom is substituted with these groups, the number is usually 2 or less, preferably 1 for each of the groups represented by ^{Ar 1} , Ar ² or Ar ^3. It is as follows.

Examples of the alkylidene group include a methylene group, an ethylidene group, an isopropylidene group, an n-butylidene group and a 2-ethylhexylidene group, which usually have 1 to 10 carbon atoms.

The repeating unit (1) is a repeating unit derived from a predetermined aromatic hydroxycarboxylic acid. As the repeating unit (1), Ar ¹ is a p-phenylene group (repeating unit derived from p-hydroxybenzoic acid), and Ar ¹ is a 2,6-naphthylene group (6-hydroxy-2). − Repeating unit derived from naphthoic acid) is preferred.

The repeating unit (2) is a repeating unit derived from a predetermined aromatic dicarboxylic acid. As the repeating unit (2), Ar ² is a p-phenylene group (repeating unit derived from terephthalic acid), Ar ² is an m-phenylene group (repeating unit derived from isophthalic acid), Ar ² Is a 2,6-naphthylene group (repetitive unit derived from 2,6-naphthalenedicarboxylic acid), and Ar ² is a diphenyl ether-4,4'-diyl group (diphenyl ether-). A repeating unit derived from 4,4'-dicarboxylic acid) is preferred.

The repeating unit (3) is a repeating unit derived from a predetermined aromatic diol, aromatic hydroxylamine or aromatic diamine. As the repeating unit (3), Ar ³ is a p-phenylene group (a repeating unit derived from hydroquinone, p-aminophenol or p-phenylenediamine), and Ar ³ is a 4,4'-biphenylylene group. (Repeat units derived from 4,4'-dihydroxybiphenyl, 4-amino-4'-hydroxybiphenyl or 4,4'-diaminobiphenyl) are preferred.

The content of the repeating unit (1) is the total amount of all repeating units (by dividing the mass of each repeating unit constituting the liquid crystal polyester by the formula amount of each repeating unit, the amount equivalent to the amount of substance of each repeating unit (mol). ) Is calculated, and the total value thereof) is usually 30 mol% or more, preferably 30 to 80 mol%, more preferably 40 to 70 mol%, and further preferably 45 to 65 mol%.

The content of the repeating unit (2) is usually 35 mol% or less, preferably 10 to 35 mol%, more preferably 15 to 30 mol%, still more preferably 17.5 to the total amount of all repeating units. It is 27.5 mol%.

The content of the repeating unit (3) is usually 35 mol% or less, preferably 10 to 35 mol%, more preferably 15 to 30 mol%, still more preferably 17.5 to the total amount of all repeating units. It is 27.5 mol%. The higher the content of the repeating unit (1), the easier it is to improve the melt fluidity, heat resistance, strength and rigidity, but if it is too high, the melt temperature and melt viscosity tend to increase, and the temperature required for molding increases. easy.

The ratio between the content of the repeating unit (2) and the content of the repeating unit (3) is expressed by [content of repeating unit (2)] / [content of repeating unit (3)] (mol / mol). It is usually 0.9 / 1-1 / 0.9, preferably 0.95 / 1-1 / 0.95, and more preferably 0.98 / 1-1 / 0.98.

The liquid crystal polyester may have two or more repeating units (1) to (3) independently of each other. Further, the liquid crystal polyester may have a repeating unit other than the repeating units (1) to (3), but the content thereof is usually 10 mol% or less, preferably 10 mol% or less, based on the total amount of all the repeating units. It is 5 mol% or less.

Since the liquid crystal polyester has a repeating unit (3) in which X and Y are oxygen atoms, that is, has a repeating unit derived from a predetermined aromatic diol, the melt viscosity tends to be low. It is preferable that the repeating unit (3) has only those in which X and Y are oxygen atoms, respectively.

Liquid crystal polyester can be produced by melt-polymerizing a raw material monomer corresponding to a repeating unit constituting the liquid crystal polyester and solid-phase polymerizing the obtained polymer (hereinafter, may be referred to as "prepolymer"). preferable. As a result, it is possible to produce a high molecular weight liquid crystal polyester having high heat resistance, strength and rigidity with good operability. The melt polymerization may be carried out in the presence of a catalyst, and examples of this catalyst include metal compounds such as magnesium acetate, stannous acetate, tetrabutyl titanate, lead acetate, sodium acetate, potassium acetate and antimony trioxide. , 4- (Dimethylamino) pyridine, 1-methylimidazole and the like, and examples thereof include a nitrogen-containing heterocyclic compound, and a nitrogen-containing heterocyclic compound is preferably used.

The flow start temperature of the liquid crystal polyester is usually 270 ° C. or higher, preferably 270 to 400 ° C., and more preferably 280 to 380 ° C. The higher the flow start temperature, the easier it is for the heat resistance, strength, and rigidity to improve, but if it is too high, the melt temperature and melt viscosity tend to increase, and the temperature required for molding tends to increase.

The flow start temperature is also called a flow temperature or a flow temperature, and is a liquid crystal polyester while raising the temperature at a rate of 4 ° C./min under a load of ^{9.8 MPa (100 kgf / cm 2) using a capillary leometer.} Is melted and extruded from a nozzle having an inner diameter of 1 mm and a length of 10 mm, which is a temperature showing a viscosity of 4800 Pa · s (48,000 poise), which is a guideline for the molecular weight of liquid crystal polyester (edited by Naoyuki Koide, “ Liquid Crystal Polymer-Synthesis / Molding / Application- ", CMC Co., Ltd., June 5, 1987, p.95).

[Glass flakes]
The liquid crystal polyester composition of the present embodiment contains 5 parts by mass or more and 80 parts by mass or less of glass flakes with respect to 100 parts by mass of the liquid crystal polyester. When the content of the glass flakes is 5 parts by mass or more, the warp of the obtained molded product can be sufficiently reduced. Further, when the content of the glass flakes is 80 parts by mass or less, the liquid crystal polyester composition can be melt-kneaded. On the other hand, when the content of the glass flakes exceeds 80 parts by mass, the viscosity of the liquid crystal polyester composition is too high, and melt kneading becomes difficult.

The lower limit of the content of the glass flakes with respect to 100 parts by mass of the liquid crystal polyester is preferably 10 parts by mass or more, and more preferably 20 parts by mass or more. When the lower limit of the content of the glass flakes is in such a range, the warpage of the obtained molded product can be further reduced.

The upper limit of the content of the glass flakes with respect to 100 parts by mass of the liquid crystal polyester is preferably 70 parts by mass or less, and more preferably 60 parts by mass or less. When the upper limit of the content of the glass flakes is in such a range, the fluidity of the liquid crystal polyester composition at the time of molding becomes sufficiently good. As a result, a compact and thin-walled molded product can be stably produced.

(Thickness)
The thickness of the glass flakes contained in the liquid crystal polyester composition of the present embodiment is 0.1 μm or more and 1.0 μm or less. When the thickness of the glass flakes is 0.1 μm or more, the warp of the obtained molded product can be sufficiently reduced. Further, when the thickness of the glass flakes is 1.0 μm or less, the fluidity of the liquid crystal polyester composition at the time of molding becomes sufficiently good. As a result, it is possible to stably produce a molded product even in a small and thin-walled molded product.

The lower limit of the thickness of the glass flakes is preferably 0.3 μm or more, and more preferably 0.5 μm or more. When the lower limit of the thickness of the glass flakes is in such a range, the warpage of the obtained molded product can be further reduced.

Further, the upper limit of the thickness of the glass flakes is preferably 0.9 μm or less, and more preferably 0.8 μm or less. When the upper limit of the thickness of the glass flakes is in such a range, the molded product can be manufactured more stably even in a small and thin-walled molded product.

The above upper limit value and lower limit value can be arbitrarily combined.

It is known that the thickness of the glass flakes used in the present embodiment does not change substantially depending on the method for producing the liquid crystal polyester composition described later. Therefore, the thickness of the glass flakes contained in the liquid crystal polyester composition can be determined by measuring the thickness of the glass flakes used.

For the thickness of the glass flakes used in the present embodiment, the glass flakes to be used were observed with a scanning electron microscope (SEM), and the thicknesses of 10 glass flakes randomly selected from the obtained images were measured. The average value is adopted.

(Volume average particle size)
The volume average particle size of the glass flakes contained in the liquid crystal polyester composition of the present embodiment is 23 μm or more and 38 μm or less. When the volume average particle diameter of the glass flakes is 23 μm or more, the warp of the obtained molded product can be sufficiently reduced. Further, when the volume average particle diameter of the glass flakes is 38 μm or less, the molded product can be stably produced even in a small and thin-walled molded product.

The lower limit of the volume average particle diameter of the glass flakes is preferably 25 μm or more, and more preferably 27 μm or more. When the lower limit of the volume average particle diameter of the glass flakes is in such a range, the warpage of the obtained molded product can be further reduced.

The upper limit of the volume average particle size of the glass flakes is preferably 36 μm or less, and more preferably 34 μm or less. When the upper limit of the volume average particle diameter of the glass flakes is in such a range, the molded product can be produced more stably even in a small and thin-walled molded product.

The above upper limit value and lower limit value can be arbitrarily combined.

The lower limit of the volume average particle size of the glass flakes used for melt-kneading with the liquid crystal polyester is preferably 25 μm or more, more preferably 40 μm or more, still more preferably 50 μm or more. It is known that the volume average particle size of glass flakes is reduced by melt-kneading. However, by melt-kneading using glass flakes having a volume average particle size of 25 μm or more, the glass flakes contained in the liquid crystal polyester composition are contained. The volume average particle diameter of the above can be easily adjusted to 23 μm or more. As a result, the warpage of the obtained molded product can be further reduced.

On the other hand, the upper limit of the volume average particle size of the glass flakes used for melt-kneading with the liquid crystal polyester is preferably 300 μm or less, more preferably 200 μm or less, still more preferably 150 μm or less. By melt-kneading using glass flakes having a volume average particle diameter of 300 μm or less, the volume average particle diameter of the glass flakes contained in the liquid crystal polyester composition can be easily adjusted to 38 μm or less. As a result, a compact and thin-walled molded product can be stably produced.

The above upper limit value and lower limit value can be arbitrarily combined.

The volume average particle size of the glass flakes contained in the liquid crystal polyester composition of the present embodiment is measured by the following method.

First, 3 g of the pellet made of the liquid crystal polyester composition of the present embodiment is heated at 600 ° C. for 3 hours to remove the resin, and the glass flakes are taken out.

Next, the obtained glass flakes are measured by a laser diffraction method. Specifically, 100 mg of glass flakes are dispersed in water, and measurement is carried out under the following measurement conditions using a laser diffraction / scattering type particle size distribution measuring device (manufactured by Horiba Co., Ltd., “LA-950V2”).

[Measurement condition]
Refractive index of particles: 1.56
Dispersion medium: Water Dispersion medium Refractive index: 1.33

(Large particle size component)
The glass flakes contained in the liquid crystal polyester composition of the present embodiment contain a large particle size component having a particle size of 100 μm or more and 400 μm or less. The ratio of the large particle size component to 100% by volume of the glass flakes is 0.1% by volume or more and 2.3% by volume or less.

When the proportion of the large particle size component is 0.1% by volume or more, the warp of the obtained molded product can be sufficiently reduced. Further, when the ratio of the large particle size component is 2.3% by volume or less, the molded product can be stably produced even in a small and thin-walled molded product. On the other hand, if the proportion of the large particle size component exceeds 2.3% by volume, shot shots may occur during the production of a small / thin-walled molded product, and a desired shape may not be obtained. It is presumed that this is because the large particle size component hinders the flow of the liquid crystal polyester.

The lower limit of the ratio of the large particle size component to 100% by volume of the glass flakes is preferably 0.4% by volume or more, and more preferably 0.6% by volume or more. When the lower limit of the proportion of the large particle size component is in such a range, the warpage of the obtained molded product can be further reduced.

Further, the upper limit of the ratio of the large particle size component to 100% by volume of the glass flakes is preferably 1.5% by volume or less, and more preferably less than 1.0% by volume. When the upper limit of the ratio of the large particle size component is in such a range, the molded product can be produced more stably even in a small and thin-walled molded product.

The above upper limit value and lower limit value can be arbitrarily combined.

The volume average particle size of the glass flakes contained in the liquid crystal polyester composition and the ratio of the large particle size component to the glass flakes can be adjusted by the particle size of the glass flakes used and the production conditions of the liquid crystal polyester composition described later. ..

The particle size of the glass flakes used can be adjusted by a conventionally known manufacturing method. The glass flakes used in this embodiment can be produced by a blow method or a rotary method.

The blow method is a method in which a nozzle is placed in a liquid tank in which molten glass is stored, air is blown from the nozzle to make a balloon, and the balloon is pulled by a roller to obtain glass flakes. The rotary method is a method in which molten glass is continuously poured into a flat plate or a cup-shaped container rotating at a high speed and stretched from the flat plate or the edge of the cup to obtain glass flakes.

As the composition of the glass flakes used in the present embodiment, a generally known composition of glass can be used. Specifically, glass having a small amount of alkali metal oxide such as E glass can be preferably used. The typical composition of E glass is shown below. The unit of composition below is mass%.

SiO ₂ : 52 to 56
Al ₂ O ₃ : 12-16
CaO: 16-25
MgO: 0-6
Na ₂ O + K ₂ O: 0 to 2 (preferably 0 to 0.8)
B ₂ O ₃ : 5-13
F ₂ : 0 to 0.5

Further, the surface of the glass flakes used in the present embodiment may be covered with a thin film of either one or both of a metal and a metal oxide. When the glass flakes used in the present embodiment contain an alkaline component, the elution of the alkaline component from the glass flakes can be prevented by coating the surface of the glass flakes with a thin film. As a result, disadvantages due to elution of the alkaline component, for example, a decrease in the adhesive force between the resin (liquid crystal polyester) and the glass flakes, discoloration of the resin (liquid crystal polyester), and the like can be suppressed.

The glass flakes used in the present embodiment may be granulated glass flakes granulated using a binder.

Granular glass flakes are made by adding a binder to the glass flakes, stirring and drying. Specific methods of adding, stirring and drying the binder are not particularly limited.

The binder is not particularly limited, but preferably contains an adhesive component and a coupling agent component, and a lubricant component such as an oil agent and a surfactant can also be used.

The adhesive component is a component for granulating glass flakes and increasing the affinity between the glass flakes and the molding resin (liquid crystal polyester). The coupling agent component is a component for reacting with the surface of glass flakes to increase the affinity between the surface of glass and the molding resin (liquid crystal polyester).

The adhesive component is not particularly limited, and organic and inorganic adhesive components can be used. Examples of the organic adhesive component include methyl cellulose, carboxymethyl cellulose, starch, carboxymethyl starch, hydroxyethyl cellulose, hydroxypropyl cellulose, polyvinyl alcohol, acrylic resin, epoxy resin, phenol resin, vinyl acetate and polyurethane resin. Examples of the inorganic adhesive component include water glass, colloidal silica, colloidal alumina and the like.

The coupling agent component is not particularly limited, and examples thereof include a silane coupling agent, a titanium-based coupling agent, an aluminum-based coupling agent, a zirconia-based coupling agent, and a mixture thereof can also be used. Examples of the silane coupling agent include γ-aminopropyltrimethoxysilane, γ-aminopropyltriethoxysilane, N-β-aminoethyl-γ-aminopropyltrimethoxysilane, γ-glycidoxypropyltrimethoxysilane, and vinyltri. Examples thereof include ethoxysilane and γ-methacryloxypropyltrimethoxysilane.

The adhesion rate (adhesion amount) of the binder in the granular glass flakes can be controlled by the concentration and amount of the binder added or sprayed to the glass flakes. That is, a predetermined amount of the binder solution is added or sprayed to a predetermined amount of flake-shaped glass so that the solid content of the binder becomes a predetermined amount. As a result, granular glass flakes having a predetermined adhesion rate can be produced. The adhesion rate of the binder is preferably 1.0% by mass or less, more preferably 0.1% by mass or more and 0.5% by mass or less.

[Other ingredients]
The liquid crystal polyester composition may contain one or more other components such as a filler other than the glass flakes of the present embodiment, an additive, and a resin other than the liquid crystal polyester, as long as the effects of the present invention are exhibited.

The filler may be a fibrous filler, a plate-shaped filler, or a spherical or other granular filler other than the fibrous and plate-shaped fillers. Further, the filler may be an inorganic filler or an organic filler.

Examples of the fibrous inorganic filler include glass fibers; carbon fibers such as pan-based carbon fibers and pitch-based carbon fibers; ceramic fibers such as silica fibers, alumina fibers and silica-alumina fibers; and metal fibers such as stainless steel fibers. Be done. Further, whiskers such as potassium titanate whiskers, barium titanate whiskers, wollast night whiskers, aluminum borate whiskers, silicon nitride whiskers, and silicon carbide whiskers can also be mentioned.

Examples of fibrous organic fillers include polyester fibers and aramid fibers.

Examples of plate-like inorganic fillers include talc, mica, graphite, wollastonite, barium sulfate and calcium carbonate. The mica may be muscovite, phlogopite, fluorine phlogopite, or tetrasilicon mica.

Examples of granular inorganic fillers include silica, alumina, titanium oxide, glass beads, glass balloons, boron nitride, silicon carbide and calcium carbonate.

Examples of additives include antioxidants, heat stabilizers, UV absorbers, antistatic agents, surfactants, flame retardants and colorants.

Examples of resins other than liquid crystal polyester include polypropylene, polyamide, polyester other than liquid crystal polyester, polysulfone, polyphenylene sulfide, polyether ketone, polycarbonate, polyphenylene ether, thermoplastic resin other than liquid crystal polyester such as polyetherimide; and phenol resin. , Epoxy resin, polyimide resin, cyanate resin and other thermocurable resins. The content of the resin other than the liquid crystal polyester is usually 0 to 20 parts by mass with respect to 100 parts by mass of the liquid crystal polyester.

<Manufacturing method of liquid crystal polyester composition>
The liquid crystal polyester composition is preferably prepared by melt-kneading the liquid crystal polyester, the glass component and other components used as necessary using an extruder and extruding them into pellets.

As the extruder, one having a cylinder, one or more screws arranged in the cylinder, and one or more supply ports provided in the cylinder is preferably used, and one place provided in the cylinder. Those having the above vent portion are more preferably used.

In order to control the volume average particle size of the glass flakes contained in the liquid crystal polyester composition and the ratio of the large particle size components to the glass flakes, the configuration of the extruder used for melt kneading and the conditions of melt kneading are changed. To do.

For example, when reducing the volume average particle size of the glass flakes contained in the liquid crystal polyester composition, it is effective to change the structure of the screw so that the shearing force becomes large as the structure of the extruder. Specifically, there is a means for changing the configuration of the kneading block to be incorporated.

Generally, it is known that the shearing action increases in the order of left-handed kneading block (L), neutral kneading block (N), and right-handed kneading block (R) (L> N> R).

Further, when the extruder has a plurality of supply ports, it is also effective to supply the glass flakes from the supply port on the upstream side. Further, when the extruder has a kneading portion, it is also effective to supply the glass flakes from the supply port on the upstream side of the kneading portion.

Further, as a condition of melt-kneading, it is effective to increase the rotation speed of the screw to be used. Further, for example, a means of lowering the cylinder temperature, increasing the melt viscosity of the molten resin, and increasing the shearing force is also effective.

According to the liquid crystal polyester composition having the above-mentioned structure, it is possible to obtain a liquid crystal polyester composition capable of stably producing a molded product even in a small and thin-walled molded product and producing a molded product having less warpage.

<Molded body>
The molded product of the present embodiment uses the above-mentioned liquid crystal polyester composition as a forming material.

As a molding method for the liquid crystal polyester composition of the present embodiment, a melt molding method is preferable. Examples thereof include an injection molding method, an extrusion molding method such as a T-die method and an inflation method, a compression molding method, a blow molding method, a vacuum forming method and a press molding. Of these, the injection molding method is preferable.

Examples of products / parts that are molded bodies of liquid crystal polyester compositions include bobbins such as optical pickup bobbins and trans bobbins; relay parts such as relay cases, relay bases, relay sprouts, and relay armor; RIMM, DDR, CPU sockets. , S / O, DIMM, Board to Board connector, FPC connector, card connector, etc. Connector; Lamp reflector, LED reflector, etc. reflector; Lamp holder, heater holder, etc. holder; Speaker vibration plate, etc. Separation claws, separation claws for printers, etc .; camera module parts; switch parts; motor parts; sensor parts; hard disk drive parts; tableware such as ovenware; vehicle parts; aircraft parts; Examples thereof include sealing members such as sealing members for use.

FIG. 1 is a schematic perspective view showing an example of an FPC connector obtained by using the liquid crystal polyester composition of the present embodiment. As shown in FIG. 1, the external dimensions of the FPC connector 100 are 18 mm × 3.5 mm × 1.0 mm. The pitch P between the metal terminals of the FPC connector 100 is 0.3 mm. The wall thickness of the minimum wall thickness portion 201 is 0.1 mm.

The liquid crystal polyester composition of the present embodiment can stably produce a molded product even in a small and thin-walled molded product, and can produce a molded product with less warpage. By using such a liquid crystal polyester composition, a molded product can be stably produced even in a small and thin-walled molded product as shown in FIG. 1, and a molded product with less warpage can be obtained.

Hereinafter, the present invention will be described with reference to Examples, but the present invention is not limited to these Examples. Each measurement was performed as follows.

<Fluid start temperature of liquid crystal polyester>
The flow start temperature of the liquid crystal polyester was measured using a flow characteristic evaluation device (“Flow Tester CFT-500 type” manufactured by Shimadzu Corporation).

First, about 2 g of a powdered sample (liquid crystal polyester) is filled in a capillary rheometer equipped with a die having an inner diameter of 1 mm and a length of 10 mm. Next, the liquid crystal polyester was melted while raising the temperature at a rate of 4 ° C./min under a load of 9.8 MPa (100 kgf / cm ^{2) and extruded from the nozzle.} At this time, a temperature showing a melt viscosity of 4800 Pa · s (48,000 poises) was measured, and this was used as the flow start temperature.

<Volume average particle size of glass flakes>
Disperse 100 mg of glass flakes in water, and use a laser diffraction / scattering particle size distribution measuring device (“LA-950V2” manufactured by HORIBA, Ltd.) to determine the volume average particle size of the glass flakes under the following measurement conditions. It was measured.

[Measurement condition]
Refractive index of particles: 1.56
Dispersion medium: Water Dispersion medium Refractive index: 1.33

<Volume average particle size of glass flakes in liquid crystal polyester composition>
3 g of the pellet-shaped liquid crystal polyester composition described later was heated at 600 ° C. for 3 hours to remove the resin, and the glass flakes were taken out. Next, the volume average particle diameter of the taken out glass flakes was measured in the same manner as the above-mentioned <volume average particle diameter of the glass flakes>.

(Ratio of large particle size components)
The ratio of the large particle size component having a particle size of 100 μm or more and 400 μm or less to 100% by volume of the glass flakes was calculated from the volume cumulative particle size distribution curve obtained by the above measurement.

<Thickness of glass flakes used>
The glass flakes to be used were observed with a scanning electron microscope (SEM), the thicknesses of 10 randomly selected glass flakes were measured from the obtained images, and the average value was measured as the thickness of the glass flakes in the examples. And said.

<Manufacturing of liquid crystal polyester 1 (LCP1)>
In a reactor equipped with a stirrer, torque meter, nitrogen gas introduction tube, thermometer and reflux condenser, 994.5 g (7.2 mol) of p-hydroxybenzoic acid, 446.9 g of 4,4'-dihydroxybiphenyl (446.9 g). 2.4 mol), 299.0 g (1.8 mol) of terephthalic acid, 99.7 g (0.6 mol) of isophthalic acid, and 1347.6 g (13.2 mol) of anhydrous acetic acid were charged, and 1-methylimidazole 0. .2 g was added and the inside of the reactor was sufficiently replaced with nitrogen gas. Then, the temperature was raised from room temperature to 150 ° C. over 30 minutes under a nitrogen gas stream, and the temperature was maintained at 150 ° C. and refluxed for 1 hour.

Next, 0.9 g of 1-methylimidazole was added, and the temperature was raised from 150 ° C. to 320 ° C. over 2 hours and 50 minutes while distilling off by-product acetic acid and unreacted acetic anhydride. Was completed to obtain a prepolymer.

The prepolymer thus obtained was cooled to room temperature and pulverized by a coarse pulverizer. The prepolymer powder is heated in a nitrogen atmosphere from room temperature to 250 ° C. over 1 hour, heated from 250 ° C. to 285 ° C. over 5 hours, and held at 285 ° C. for 3 hours to form a solid phase. Polymerization was performed.
The flow start temperature of the obtained LCP1 was 327 ° C.

<Manufacturing of liquid crystal polyester 2 (LCP2)>
994.5 g (7.2 mol) of p-hydroxybenzoic acid, 446.9 g of 4,4'-dihydroxybiphenyl in a reactor equipped with a stirrer, torque meter, nitrogen gas introduction tube, thermometer and reflux condenser. 2.4 mol), 239.2 g (1.44 mol) of terephthalic acid, 159.5 g (0.96 mol) of isophthalic acid and 1347.6 g (13.2 mol) of anhydrous acetic acid were charged, and 1-methylimidazole 0. 2 g was added and the inside of the reactor was sufficiently replaced with nitrogen gas.
Then, the temperature was raised from room temperature to 150 ° C. over 30 minutes under a nitrogen gas stream, and the temperature was maintained at 150 ° C. and refluxed for 1 hour.

Next, 0.9 g of 1-methylimidazole was added, and the temperature was raised from 150 ° C. to 320 ° C. over 2 hours and 50 minutes while distilling off by-product acetic acid and unreacted acetic anhydride. Was completed to obtain a prepolymer.

The prepolymer thus obtained was cooled to room temperature and pulverized by a coarse pulverizer. The prepolymer powder was heated in a nitrogen atmosphere from room temperature to 220 ° C. over 1 hour, heated from 220 ° C. to 240 ° C. over 0.5 hours, and held at 240 ° C. for 10 hours. Solid phase polymerization was performed. The flow start temperature of the obtained LCP2 was 291 ° C.

<Glass flakes>
The following three types of glass flakes were used.
Glass flakes 1: MEG160FY-M03
(Made by Nippon Sheet Glass Co., Ltd., volume average particle diameter 103 μm, thickness 0.7 μm)
Glass flakes 2: MEG040FY
(Made by Nippon Sheet Glass Co., Ltd., volume average particle diameter 43 μm, thickness 0.7 μm)
Glass flakes 3: FTD025FY-F02
(Made by Nippon Sheet Glass Co., Ltd., volume average particle diameter 32 μm, thickness 0.5 μm)

<Manufacturing of liquid crystal polyester composition>
Using the liquid crystal polyester and glass flakes described above, the liquid crystal polyester compositions of Examples 1 to 4 and Comparative Examples 1 to 6 were produced.

[Examples 1 to 4, Comparative Examples 1 to 5]
A liquid crystal polyester composition using "PCM-30 type" (screw diameter: 29 mm, effective screw length / screw diameter: 25) manufactured by Ikekai Iron Works Co., Ltd. shown in FIG. 2 as a biaxial isodirectional rotary extruder. Got The configuration of the extruder is as follows.
Hopper part 5: Supply port Cylinder 1 (C1): First kneading zone Cylinder 2 (C2): Second kneading zone Vent 4: Atmospheric vent Cylinder 3 (C3): Third kneading zone Cylinder head (CH): 3Φmm 1 hole

Liquid crystal polyester and glass flakes were blended in the blending ratios shown in Table 1, and then supplied from the hopper section. The set temperatures of C1, C2, C3, and CH were the temperatures shown in Table 1. Three left-handed kneading blocks (L) or three right-handed kneading blocks (R) were appropriately incorporated into C1, C2, and C3 to form a screw configuration shown in Table 1. The extrusion rate was 6 kg / hour, and the rotation speed of the extruder was 150 rpm. After melt-kneading using an extruder having the above structure, a pellet-shaped liquid crystal polyester composition was obtained by a strand cutter.

[Comparative Example 6]
When the rotation speed of the extruder was 150 rpm and melt-kneaded under the conditions shown in Table 1, the strands were brittle and a pellet-shaped liquid crystal polyester composition could not be obtained.

<< Evaluation 1 >>
<Granulation property>
The granulation property of the liquid crystal polyester compositions of Examples 1 to 4 and Comparative Examples 1 to 6 was evaluated. Those that could be pelletized by the above-mentioned extruder were designated as "○", and those that could not be pelletized were designated as "x".

The obtained pellet-shaped liquid crystal polyester composition was evaluated by the following method. The results are shown in Table 2.

<< Evaluation 2 >>
<Standard deviation of filling peak pressure>
Using a pellet-shaped liquid crystal polyester composition, injection molding was performed under the following molding conditions to obtain an FPC connector shown in FIG. The filling peak pressure when the FPC connector was molded was measured. This measurement was performed for 10 moldings to determine the standard deviation of the filling peak pressure. It can be said that the smaller the standard deviation, the smaller the variation in the filling peak pressure, and the less likely it is that a short shot will occur during molding.

[Molding condition]
Molding machine: "ROBOSHOT S-2000i30B" manufactured by FANUC Co., Ltd.
Cylinder temperature; 350 ° C
Mold temperature: 70 ° C
Injection speed: 200 mm / sec Holding pressure: 200 kgf / cm ²
Holding time: 1 second Cooling time: 7 seconds Screw rotation speed: 100 rpm
Screw back pressure: 40 kgf / cm ²

<Amount of warpage of FPC connector>
Using the three FPC connectors obtained in the above <Standard deviation of filling peak pressure>, the measuring table (glass substrate) of the flatness measuring module "core9030c" manufactured by Cores Co., Ltd. so that the surface 100A is the bottom surface. ) Was installed. Next, the amount of warpage from the glass substrate is measured every 0.5 mm along the long side 100a, the maximum value of the amount of warpage of each FPC connector is obtained, and the average value of the obtained maximum values is the maximum amount of warpage. And said.

The liquid crystal polyester compositions of Examples 1 to 4 and Comparative Examples 1 to 6 were comprehensively evaluated according to the following criteria.
◯: The standard deviation of the filling peak pressure is 50 kgf / cm ² or less, and the maximum warpage amount is less than 0.08 mm.
X: The standard deviation of the filling peak pressure ^{is more than 50 kgf / cm 2} , or the maximum warp amount is 0.08 mm or more.

As shown in Table 2, the liquid crystal polyester compositions of Examples 1 to 4 to which the present invention was applied had a ^{sufficiently small standard deviation of the filling peak pressure of 50 kgf / cm 2} or less.

In the liquid crystal polyester compositions of Examples 1 to 4, the volume average particle size of the glass flakes was 38 μm or less. Further, the ratio of the large particle size component to 100% by volume of the glass flakes was 2.3% by volume or less. Therefore, it is considered that the glass flakes do not hinder the flow of the liquid crystal polyester and the filling peak pressure is stable. Therefore, the liquid crystal polyester compositions of Examples 1 to 4 to which the present invention is applied are less likely to cause a short shot during molding, and a molded product can be stably produced.

Further, the FPC connector obtained by using the liquid crystal polyester compositions of Examples 1 to 4 had a maximum warp amount of less than 0.08 mm, which was sufficiently small.

In the liquid crystal polyester compositions of Examples 1 to 4, the volume average particle diameter of the glass flakes was 23 μm or more. Further, the ratio of the large particle size component to 100% by volume of the glass flakes was 0.1% by volume or more. It is considered that the warpage of the obtained FPC connector was suppressed by these.

On the other hand, the FPC connector obtained by using the liquid crystal polyester compositions of Comparative Examples 1 to 3 had a maximum warp amount of less than 0.08 mm, which was sufficiently small. However, the standard deviation of the filling peak pressure of this liquid crystal polyester composition ^{exceeded 50 kgf / cm 2,} which was large.

Further, in the liquid crystal polyester compositions of Comparative Example 4 and Comparative Example 5, the standard deviation of the filling peak pressure was 50 kgf / cm ² or less, which was sufficiently small. However, the FPC connector obtained by using this liquid crystal polyester composition had a large maximum warp amount of 0.08 mm or more.

From the above results, it was confirmed that the present invention is useful.

Claims (3)

Contains 5 parts by mass or more and 80 parts by mass or less of glass flakes with respect to 100 parts by mass of liquid crystal polyester.
The thickness of the glass flakes is 0.1 μm or more and 1.0 μm or less.
The volume average particle size of the glass flakes measured by the laser diffraction method is 23 μm or more and 38 μm or less.
The glass flakes contain a large particle size component having a particle size of 100 μm or more and 400 μm or less.
A liquid crystal polyester composition in which the ratio of the large particle size component to 100% by volume of the glass flakes is 0.1% by volume or more and 1.7% by volume or less. The liquid crystal polyester composition according to claim 1, wherein the ratio of the large particle size component to 100% by volume of the glass flakes is 0.1% by volume or more and less than 1.0% by volume. A molded product using the liquid crystal polyester composition according to claim 1 or 2 as a forming material.

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