WO2012105469A1 - Liquid-crystal polyester and manufacturing process therefor - Google Patents

Abstract

The present invention addresses the problem of providing a liquid-crystal polyester having high lightness. The present invention pertains to a liquid-crystal polyester which comprises repeating units (1) derived from an aromatic hydroxycarboxylic acid, repeating units (2) derived from an aromatic dicarboxylic acid, and repeating units (3) derived from an aromatic diol, an aromatic hydroxylamine or an aromatic diamine. In the liquid-crystal polyester, the contents of the repeating units (1), (2) and (3) are 50 to 80mol%, 10 to 25mol%, and 10 to 25mol%, respectively, relative to the sum total of all the repeating units, and the content of repeating units (A) that each have a 1,2- or 1,3-phenylene skeleton in the backbone chain is 5 to 30mol% relative to the sum total of all the repeating units. Further, the liquid-crystal polyester exhibits a flow initiation temperature of 270 to 320°C.

Description

Liquid crystal polyester and method for producing the same

The present invention relates to a liquid crystal polyester and a method for producing the same.

Liquid crystalline polyesters are considered as materials for various products and parts, including electrical and electronic parts, because they have excellent melt flow properties and high heat resistance, strength, and rigidity. When liquid crystal polyester is mixed with a white pigment and used as a material for a reflector of an LED (light emitting diode) light emitting device or the like, the reflectance of the reflector is increased and the reflected light is less tinged with color. As described above, high brightness is required for the liquid crystal polyester. As such a liquid crystal polyester, for example, Patent Document 1 discloses a liquid crystal polyester having a yellowness YI of 32 or less and a lightness L of 75 or more, specifically derived from p-hydroxybenzoic acid. 60 mol% of repeating units, 20 mol% of repeating units derived from terephthalic acid, 5 mol% of repeating units derived from isophthalic acid, and 20 mol% of repeating units derived from 4,4-dihydroxybiphenyl, Liquid crystalline polyester having a flow start temperature of 327 ° C., 60 mol% of repeating units derived from p-hydroxybenzoic acid, 18 mol% of repeating units derived from terephthalic acid, and 2 mol% of repeating units derived from isophthalic acid Liquid crystalline polyester having 20 mol% of repeating units derived from 4,4-dihydrokibiphenyl and having a flow initiation temperature of 360 ° C. Discloses a liquid crystal polyester having 73 mol% of repeating units derived from p-hydroxybenzoic acid, 27 mol% of returning units derived from 6-hydroxy-2-naphthoic acid and having a flow initiation temperature of 290 ° C. Yes.

JP 2004-256673 A

An object of the present invention is to provide a liquid crystal polyester having higher brightness.

In order to achieve the above object, the present invention provides a repeating unit (1) derived from an aromatic hydroxycarboxylic acid, a repeating unit (2) derived from an aromatic dicarboxylic acid, an aromatic diol, an aromatic hydroxyamine or an aromatic The repeating unit (3) derived from a group diamine, and the content of the repeating unit (1) is 50 to 80 mol% based on the total amount of all repeating units, and the repeating unit (2) The content of the repeating unit (3) is 10 to 25 mol% with respect to the total amount of all repeating units, and the content of the repeating unit (3) is 10 to 25 mol% with respect to the total amount of all repeating units. The content of the repeating unit (A) containing a 1,2-phenylene skeleton or a 1,3-phenylene skeleton in the main chain is 5 to 30 mol% with respect to the total amount of all the repeating units, and the flow starts. The temperature is 270-320 ° C To provide a liquid crystal polyester.

The present invention is also a preferred method for producing the liquid crystal polyester, wherein the raw material monomer is an aromatic hydroxycarboxylic acid, an aromatic dicarboxylic acid, an aromatic diol, an aromatic hydroxyamine, and an aromatic diamine. A step of obtaining an aromatic acyloxycarboxylic acid and an aromatic diacyl compound by acylating the aromatic hydroxycarboxylic acid and the aromatic compound with an acid anhydride, respectively, using at least one aromatic compound selected from ), The aromatic acyloxycarboxylic acid, the aromatic diacyl compound, and the aromatic dicarboxylic acid are melt-polymerized to obtain a melt polymer, and the melt polymer is solid-phase polymerized. Step (3) of obtaining a solid-phase polymer, wherein the amount of the aromatic hydroxycarboxylic acid used is that of all the raw material monomers The amount of the aromatic dicarboxylic acid used is 50 to 80 mol% with respect to the measurement, and the amount of the aromatic compound used is 10 to 25 mol% with respect to the total amount of all raw material monomers. The amount of the raw material monomer (A), which is 10 to 25 mol% based on the total amount of all raw material monomers and contains a 1,2-phenylene skeleton or a 1,3-phenylene skeleton in the main chain, Provided is a method for producing a liquid crystal polyester, which is 5 to 30 mol% with respect to the total amount, and wherein the upper limit of the solid phase polymerization temperature in the step (3) is 220 to 270 ° C.

Since the liquid crystal polyester of the present invention has high brightness, a reflective plate with high reflectance and less reflected light can be obtained by using a liquid crystal polyester composition obtained by blending a white pigment therein. .

The liquid crystal polyester of the present invention is derived from a repeating unit (1) derived from an aromatic hydroxycarboxylic acid, a repeating unit (2) derived from an aromatic dicarboxylic acid, an aromatic diol, an aromatic hydroxyamine or an aromatic diamine. And repeating unit (3).
The repeating unit (1) is a divalent residue obtained by removing the hydrogen atom of the hydroxyl group and the hydroxyl group of the carboxyl group from an aromatic hydroxycarboxylic acid, and the repeating unit (2) is an aromatic group. Divalent acid is a divalent residue obtained by removing each hydroxyl group of the two carboxyl groups, and the repeating unit (3) is obtained by removing each hydrogen atom of the two hydroxyl groups from the aromatic diol. It is a divalent residue, or is a divalent residue obtained by removing a hydrogen atom of the hydroxyl group and a hydrogen atom of the amino group from an aromatic hydroxyamine. It is a divalent residue obtained by removing each hydrogen atom of one amino group.

Examples of the repeating unit (1) include a repeating unit represented by the following formula (1). Examples of the repeating unit (2) include a repeating unit represented by the following formula (2). Examples of (3) include repeating units represented by the following formula (3).

(1) —O—Ar ¹ —CO—
(2) —CO—Ar ² —CO—
(3) —X—Ar ³ —Y—

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

(4) —Ar ⁴ —Z—Ar ⁵ —

(Ar ⁴ and Ar ⁵ each 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.)

As said halogen atom, a fluorine atom, a chlorine atom, a bromine atom, and an iodine atom are mentioned. 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, 2-ethylhexyl group, Examples thereof include an n-octyl group and an n-decyl group, and the carbon number thereof is usually 1 to 10. 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, and the number of carbon atoms is usually 6-20. . When the hydrogen atom is substituted with these groups, the number is usually 2 or less for each group represented by Ar ¹ , Ar ² or Ar ³ , and preferably 1 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, and the number of carbon atoms is usually 1 to 10.

As the repeating unit (1), in the formula (1), Ar ¹ is a p-phenylene group or a 2,6-naphthylene group, that is, p-hydroxybenzoic acid or 6-hydroxy-2-naphthoic acid. Derived repeating units are preferred.

As the repeating unit (2), in the formula (2), Ar ² is an o-phenylene group, m-phenylene group, p-phenylene group or 2,6-naphthylene group, that is, phthalic acid, isophthalic acid Repeating units derived from terephthalic acid or 2,6-naphthalenedicarboxylic acid are preferred.

As the repeating unit (3), in the above formula (3), X and Y are each an oxygen atom, and Ar ³ is an o-phenylene group, an m-phenylene group, a p-phenylene group, or a 4,4′-biphenylylene group. Or a 2,6-naphthylene group, in the above formula (3), X is an oxygen atom, Y is an imino group, Ar ³ is an o-phenylene group, an m-phenylene group or a p-phenylene group. A compound in which X and Y are each an imino group and Ar ³ is an o-phenylene group, an m-phenylene group or a p-phenylene group, that is, catechol, resorcinol, hydroquinone, 4,4'-dihydroxybiphenyl, 2,6-naphthalenediol, o-aminophenol, m-aminophenol, p-aminophenol, o Phenylenediamine, repeating units derived from a m- phenylenediamine or p- phenylenediamine preferred.

The content of the repeating unit (1) is the total amount of all the repeating units (the mass equivalent amount of each repeating unit by dividing the mass of each repeating unit constituting the liquid crystalline polyester by the formula weight of each repeating unit ( Mol), and the total value thereof) is preferably 50 to 80 mol%, more preferably 50 to 70 mol%. The content of the repeating unit (2) is preferably 10 to 25 mol%, more preferably 15 to 25 mol%, based on the total amount of all repeating units. The content of the repeating unit (3) is preferably 10 to 25 mol%, more preferably 15 to 25 mol%, based on the total amount of all repeating units.

If the content of the repeating unit (1) is too high and the content of the repeating units (2) and (3) is too low, the melting temperature and melt viscosity of the liquid crystal polyester tend to increase, and the temperature required for molding the liquid crystal polyester. Therefore, the liquid crystal polyester is likely to be colored at the time of molding, and the brightness of the molded body is likely to be lowered. If the content of the repeating unit (1) is too small and the content of the repeating units (2) and (3) is too large, the heat resistance, strength and rigidity of the liquid crystal polyester are liable to decrease, and the molded body deforms at high temperatures. It becomes easy to do.

The ratio between the content of the repeating unit (2) and the content of the repeating unit (3) is expressed as [content of repeating unit (2)] / [content of repeating unit (3)] (mol / mol). In general, it is 0.9 / 1 to 1 / 0.9, preferably 0.95 / 1 to 1 / 0.95, and more preferably 0.98 / 1 to 1 / 0.98.

The liquid crystal polyester of the present invention may have two or more repeating units (1) to (3) independently. The liquid crystalline polyester of the present invention may have a repeating unit other than the repeating units (1) to (3), but the content thereof is usually 10 mol% or less with respect to the total amount of all repeating units. Preferably, it is 5 mol% or less.

The liquid crystalline polyester of the present invention preferably has a repeating unit (3) in which X and Y are each an oxygen atom, that is, a repeating unit derived from a predetermined aromatic diol, and X and Y are each an oxygen atom. It is more preferable to have only what is. As a result, the melt viscosity of the liquid crystal polyester tends to be low, and the temperature required for the molding of the liquid crystal polyester can be lowered. Therefore, the liquid crystal polyester is difficult to be colored during molding and the brightness of the molded body is difficult to decrease.

In the liquid crystal polyester of the present invention, the repeating unit (A) containing a 1,2-phenylene skeleton or a 1,3-phenylene skeleton in the main chain is preferably from 5 to 30 mol%, preferably from the total amount of all repeating units. 8 to 25 mol%. In other words, the repeating unit (A) is a repeating unit containing a 1,2-phenylene group or a 1,3-phenylene group which may have a substituent or a fused ring.

When the content of the repeating unit (A) is too large, it is necessary to increase the polymerization degree of the liquid crystal polyester in order to set the flow start temperature of the liquid crystal polyester to 270 ° C. or higher as described later. Since it is necessary to increase the polymerization temperature, the liquid crystal polyester is easily colored during solid-phase polymerization, and the lightness of the liquid crystal polyester is likely to be lowered. When the content of the repeating unit (A) is too small, it is necessary to lower the degree of polymerization of the liquid crystal polyester in order to make the flow start temperature of the liquid crystal polyester not more than 320 ° C. as described later. And oligomers remain, and the heat resistance, strength, and rigidity of the liquid crystal polyester are likely to decrease, so that the molded body is likely to foam at a high temperature or deformed at a high temperature.

Examples of the repeating unit (A) that is the repeating unit (1) include a repeating unit represented by the following formula (1A). Examples of the repeating unit (A) that is the repeating unit (2) include the following formula: Examples of the repeating unit (A) which is the repeating unit (3) include a repeating unit represented by the following formula (3A).

(1A) —O—Ar ^1A —CO—
(2A) -CO-Ar ^2A -CO-
(3A) -X-Ar ^3A -Y-

(Ar ^1A , Ar ^2A and Ar ^3A each independently represents an o-phenylene group, m-phenylene group, 1,2-naphthylene group, 1,3-naphthylene group or 1,4-naphthylene group. X and Y each independently represents an oxygen atom or an imino group, wherein each hydrogen atom in the group represented by Ar ^1A , Ar ^2A or Ar ^3A is independently substituted with a halogen atom, an alkyl group or an aryl group. May be.)

Examples of the halogen atom, alkyl group, and aryl group are the same as the examples of the halogen atom, alkyl group, and aryl group in Ar ¹ to Ar ³ , respectively. The liquid crystalline polyester of the present invention comprises a repeating unit (A) that is the repeating unit (1), a repeating unit (A) that is the repeating unit (2), and a repeating unit (A) that is the repeating unit (3). You may have 2 or more types each independently.

As the repeating unit (A), Ar ^2A in the formula (2A) is an o-phenylene group or m-phenylene group, X and Y in the formula (3A) are each an oxygen atom, Ar ^3A Wherein o is an o-phenylene group or m-phenylene group, and in the formula (3A), X is an oxygen atom, Y is an imino group, and Ar ^3A is an o-phenylene group or an m-phenylene group Or in the formula (3A), X and Y are each an imino group, and Ar ^3A is preferably an o-phenylene group or an m-phenylene group, that is, phthalic acid, isophthalic acid, catechol, resorcinol, o -Repeating units derived from aminophenol, m-aminophenol, o-phenylenediamine or m-phenylenediamine are preferred .

Further, the liquid crystalline polyester of the present invention preferably has a repeating unit content containing a naphthalene ring, such as a repeating unit derived from hydroxynaphthoic acid, naphthalene dicarboxylic acid or naphthalene diol, with respect to the total amount of all repeating units. It is 0 to 30 mol%, more preferably 0 to 25 mol%, still more preferably 0 to 20 mol%. Thereby, the brightness of the liquid crystal polyester is easily improved.

The liquid crystalline polyester of the present invention has a flow start temperature of 270 to 320 ° C., preferably 290 to 320 ° C. The flow start temperature is also called flow temperature or flow temperature, and melts the liquid crystalline polyester using a capillary rheometer while increasing the temperature at a rate of 4 ° C./min under a load of 9.8 MPa (100 kg / cm ² ). And a temperature indicating a viscosity of 4800 Pa · s (48000 poise) when extruded from a nozzle having an inner diameter of 1 mm and a length of 10 mm, which is a measure of the molecular weight of the liquid crystalline polyester (“Naked Liquids”, “Liquid Crystal Polymer” -See "Synthesis / Molding / Application-", CMC Corporation, June 5, 1987, p. 95).

If the flow start temperature is too high, the temperature required for molding the liquid crystal polyester becomes high, so that the liquid crystal polyester is easily colored during molding, and the lightness of the molded body is likely to be lowered. When the flow start temperature is too low, the heat resistance, strength and rigidity of the liquid crystal polyester are likely to be lowered, and the molded body is likely to be deformed at a high temperature.

The liquid crystalline polyester of the present invention can be produced by polymerizing (polycondensation) raw material monomers of the type and amount corresponding to the repeating units constituting them under predetermined conditions.

As the raw material monomer, aromatic hydroxycarboxylic acid, aromatic dicarboxylic acid, and at least one aromatic compound selected from the group consisting of aromatic diol, aromatic hydroxyamine, and aromatic diamine are used.

The aromatic hydroxycarboxylic acid is preferably at least one compound selected from the group consisting of p-hydroxybenzoic acid and 6-hydroxy-2-naphthoic acid. The aromatic dicarboxylic acid is preferably at least one compound selected from the group consisting of phthalic acid, isophthalic acid, terephthalic acid and 2,6-naphthalenedicarboxylic acid. The aromatic compounds include catechol, resorcinol, hydroquinone, o-aminophenol, m-aminophenol, p-aminophenol, o-phenylenediamine, m-phenylenediamine, p-phenylenediamine, 4,4′-dihydroxybiphenyl and It is preferably at least one compound selected from the group consisting of 2,6-naphthalenediol.

The amount of aromatic hydroxycarboxylic acid used is the total amount of all raw material monomers (the mass of each raw material monomer that gives each repeating unit constituting the liquid crystal polyester is divided by the molecular weight of each raw material monomer to determine the substance of each raw material monomer. The amount (mole) is determined and the total value thereof) is 50 to 80 mol%, preferably 50 to 70 mol%. The amount of aromatic dicarboxylic acid used is 10 to 25 mol%, preferably 15 to 25 mol%, based on the total amount of all raw material monomers. The amount of the aromatic compound used is 10 to 25 mol%, preferably 15 to 25 mol%, based on the total amount of all raw material monomers.

The ratio between the amount of aromatic dicarboxylic acid used and the amount of aromatic compound used is usually expressed as [Aromatic dicarboxylic acid usage] / [Aromatic compound usage] (mol / mol). 0.9 / 1 to 1 / 0.9, preferably 0.95 / 1 to 1 / 0.95, and more preferably 0.98 / 1 to 1 / 0.98.

In addition, as a raw material monomer, you may use compounds other than aromatic hydroxycarboxylic acid, aromatic dicarboxylic acid, and the said aromatic compound, but the usage-amount is 10 mol% normally with respect to the total amount of all the raw material monomers. Hereinafter, it is preferably 5 mol% or less.

As the aromatic compound, it is preferable to use an aromatic diol, and it is more preferable to use only an aromatic diol.

The amount of the raw material monomer (A) containing a 1,2-phenylene skeleton or a 1,3-phenylene skeleton in the main chain is 5 to 30 mol%, preferably 8 to 25 mol, based on the total amount of all raw material monomers. %. In other words, the raw material monomer (A) is a compound containing a 1,2-phenylene group or a 1,3-phenylene group which may have a substituent or a fused ring.

The raw material monomer (A) is at least one compound selected from the group consisting of phthalic acid, isophthalic acid, catechol, resorcinol, o-aminophenol, m-aminophenol, o-phenylenediamine and m-phenylenediamine. Is preferred.

The amount of the raw material monomer containing a naphthalene ring, such as hydroxynaphthoic acid, naphthalene dicarboxylic acid and naphthalene diol, is preferably 0 to 30 mol%, more preferably 0 to 25, based on the total amount of all raw material monomers. The mol% is more preferably 0 to 20 mol%.

In the production of the liquid crystalline polyester, first, as the step (1), the aromatic hydroxycarboxylic acid and the aromatic compound are acylated with an acid anhydride to obtain an aromatic acyloxycarboxylic acid and an aromatic diacyl compound, and then the step (1) As 2), an aromatic acyloxycarboxylic acid, an aromatic diacyl compound, and an aromatic dicarboxylic acid are melt-polymerized to obtain a melt polymer, and then in step (3), the melt polymer is solid-phase polymerized, This is done by obtaining a solid phase polymer.

The acid anhydride used in the step (1) is preferably a fatty acid anhydride. Examples thereof include acetic anhydride, propionic anhydride, butyric anhydride, isobutyric anhydride, valeric anhydride, pivalic anhydride, anhydrous 2 -Ethylhexanoic acid, monochloroacetic anhydride, dichloroacetic anhydride, trichloroacetic anhydride, monobromoacetic anhydride, dibromoacetic anhydride, tribromoacetic anhydride, monofluoroacetic anhydride, difluoroacetic anhydride, trifluoroacetic anhydride, glutaric anhydride, maleic anhydride Succinic anhydride and β-bromopropionic anhydride, and two or more thereof may be used. Among these, acetic anhydride, propionic anhydride, butyric anhydride and isobutyric anhydride are preferable, and acetic anhydride is more preferable.

The amount of the acid anhydride to be used is preferably 1 to 1.1 mol times, more preferably 1.01 with respect to the total amount of the hydroxyl group of the aromatic hydroxycarboxylic acid and the hydroxyl group and amino group of the aromatic compound. ˜1.08 mole times. If the amount of the acid anhydride is too large, the liquid crystal polyester is likely to be colored, and the lightness of the liquid crystal polyester is likely to be lowered. If the amount of acid anhydride is too small, the degree of polymerization of the liquid crystal polyester tends to be low, the raw material monomers and oligomers remain in the liquid crystal polyester, and the heat resistance, strength, and rigidity of the liquid crystal polyester tend to decrease. It becomes easy for the molded body to foam at a high temperature or to deform the molded body at a high temperature.

Step (1) is preferably performed at 130 to 180 ° C. in an inert gas atmosphere such as nitrogen gas. In step (1), aromatic dicarboxylic acid may be present.

Step (2) is preferably performed at 130 to 400 ° C. and preferably 150 to 350 ° C. in an atmosphere of an inert gas such as nitrogen gas. In addition, the step (2) is preferably performed by raising the temperature at a rate of 0.1 to 50 ° C./min while distilling off the by-product carboxylic acid and unreacted acid anhydride, More preferably, the temperature is increased at a rate of 5 ° C./min.

In addition, it is preferable to perform step (1) and / or (2) in the presence of a catalyst. Thereby, acylation and / or melt polymerization proceed smoothly, and the brightness of the liquid crystal polyester is easily improved.

Examples of the catalyst include magnesium acetate, stannous acetate, tetrabutyl titanate, lead acetate, sodium acetate, potassium acetate, antimony trioxide and other metal compounds, and 4- (dialkylamino) such as 4- (dimethylamino) pyridine. Examples thereof include pyridine compounds such as pyridine, and imidazole compounds such as 1-alkylimidazole such as 1-methylimidazole. Among these, an imidazole compound is preferable from the viewpoint of lightness of the liquid crystal polyester.

The amount of the catalyst used is preferably 0.005 to 1 part by mass, more preferably 0.05 to 0.5 part by mass with respect to 100 parts by mass in total of all raw material monomers.

Step (3) is performed with the upper limit of the solid-state polymerization temperature being 220 to 270 ° C., preferably 225 to 265 ° C., more preferably 230 to 255 ° C. If the upper limit of the solid phase polymerization temperature is too high, the liquid crystal polyester is likely to be colored during the solid phase polymerization, and the brightness of the liquid crystal polyester is likely to be lowered. If the upper limit of the solid-phase polymerization temperature is too low, the polymerization degree of the liquid crystal polyester tends to be low, and raw material monomers and oligomers remain in the liquid crystal polyester, and the heat resistance, strength, and rigidity of the liquid crystal polyester tend to decrease. The molded body is easily foamed at a high temperature, and the molded body is easily deformed at a high temperature.

Further, the step (3) is preferably performed by raising the temperature to an upper limit temperature in an atmosphere of an inert gas such as nitrogen gas and holding the upper limit temperature for 3 to 20 hours.

The liquid crystal polyester of the present invention thus obtained has high lightness, and specifically, it is preferably 86 or more, more preferably 87 or more, expressed by the lightness L ^* of L ^* a ^* b ^* color system according to JIS Z8729. .

Since the liquid crystal polyester of the present invention has high brightness, the liquid crystal polyester composition of the present invention obtained by blending a white pigment therein is suitably used as a material for a reflector.

As the white pigment, for example, inorganic compounds such as zinc oxide, zinc sulfide, lead white, and titanium oxide are preferably used, and two or more of them can be used as necessary. Of these, titanium oxide is preferable.

The particle size of the white pigment is preferably 0.05 to 2 μm, more preferably expressed as a volume average value, because the white pigment is easily dispersed in the liquid crystal polyester and a reflector having high reflectance is easily obtained. Is 0.1 to 1 μm, more preferably 0.15 to 0.5 μm, and particularly preferably 0.2 to 0.4 μm.

The volume average particle size referred to here is obtained by photographing a white pigment with a scanning electron microscope (SEM), and using the obtained SEM photograph as an image analyzer (for example, “Luzex IIIU” manufactured by Nireco Corporation). Is a particle size when the cumulative degree is 50% in a distribution curve obtained by accumulating them on a volume basis.

The content of the white pigment in the liquid crystal polyester composition of the present invention is preferably 20 to 200 parts by weight, more preferably 25 to 150 parts by weight, and further preferably 40 to 40 parts by weight with respect to 100 parts by weight of the liquid crystal polyester. 100 parts by mass.

Titanium oxide, which is a preferred example of a white pigment, may have a rutile type, anatase type, or a mixture of both, but has a high reflectance, Since it is easy to obtain a reflector having excellent weather resistance, those containing rutile type titanium oxide are preferred, and those substantially consisting only of rutile type titanium oxide are more preferred.

The titanium oxide may be subjected to a surface treatment. For example, dispersibility and weather resistance can be improved by performing a surface treatment using an inorganic metal oxide. As the inorganic metal oxide, aluminum oxide (alumina) is preferably used. From the viewpoint of heat resistance and strength, it is preferable to use titanium oxide that has not been surface-treated.

The production method of titanium oxide may be a chlorine method or a sulfuric acid method, but the chlorine method is preferred when producing a rutile type titanium oxide. When producing titanium oxide by the chlorine method, first, ore (synthetic rutile ore obtained from rutile or ilmenite ore), which is a titanium source, and chlorine are reacted at around 1000 ° C. to obtain crude titanium tetrachloride. It is preferable that titanium tetrachloride is purified by rectification and then oxidized with oxygen.

The liquid crystal polyester composition of the present invention may contain one or more other components such as fillers, additives other than white pigments, and resins other than liquid crystal polyesters.

The filler may be a fibrous filler, a plate-like filler, or a spherical or other granular filler other than the fibrous and plate-like materials. The filler may be an inorganic filler or an organic filler. Examples of fibrous inorganic fillers 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. It is done. In addition, whiskers such as potassium titanate whisker, barium titanate whisker, wollastonite whisker, aluminum borate whisker, silicon nitride whisker, and silicon carbide whisker are also included. Examples of fibrous organic fillers include polyester fibers and aramid fibers. Examples of the plate-like inorganic filler include talc, mica, graphite, wollastonite, glass flake, barium sulfate, and calcium carbonate. Mica may be muscovite, phlogopite, fluorine phlogopite, or tetrasilicon mica. Examples of the particulate inorganic filler include silica, alumina, titanium oxide, glass beads, glass balloons, boron nitride, silicon carbide and calcium carbonate. The content of the filler in the liquid crystal polyester composition is usually 0 to 100 parts by mass with respect to 100 parts by mass of the liquid crystal polyester.

Examples of additives other than white pigments include antioxidants, heat stabilizers, light stabilizers, antistatic agents, surfactants, and flame retardants. In addition, as a colorant other than the white pigment, a pigment or dye other than the white pigment may be used. The content of additives other than the white pigment is usually 0 to 5 parts by mass with respect to 100 parts by mass of the liquid crystal polyester.

Examples of resins other than liquid crystal polyesters include polypropylene, polyamide, polyesters other than liquid crystal polyesters, thermoplastic resins other than liquid crystal polyesters such as polysulfone, polyphenylene sulfide, polyether ketone, polycarbonate, polyphenylene ether, and polyetherimide; and phenol resins And thermosetting resins such as epoxy resins, polyimide resins, and cyanate 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.

The liquid crystal polyester composition of the present invention is preferably prepared by melt-kneading a liquid crystal polyester, a white pigment and other components used as necessary using an extruder, extruding into a strand shape, and pelletizing. . 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 further one place provided in the cylinder What has the above vent part is used more preferably.

By molding the liquid crystal polyester composition of the present invention thus obtained, a reflector having high reflectivity and less reflected light can be obtained. As a molding method of the liquid crystal polyester composition, a melt molding method is preferable, and 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 molding method, and a press. Examples include molding. Of these, the injection molding method is preferable. According to the injection molding method, a reflector having a thin part and a reflector having a complicated shape can be easily obtained, and the thickness of the thin part is particularly 0.01 mm to 3.0 mm, preferably 0.02 to 2. The injection molding method is suitable for obtaining a small reflector having a thickness of 0.0 mm, more preferably 0.05 to 1.0 mm.

The reflector of the present invention thus obtained is suitably used as a reflector for reflecting light, particularly for reflecting visible light, in the fields of electricity, electronics, automobiles, machines and the like. For example, it is suitably used as a reflector of a lamp reflector of a light source device such as a halogen lamp or HID, a light emitting device using a light emitting element such as an LED or an organic EL, or a display device. In particular, it is suitably used as a reflector of a light emitting device using LEDs.

[Measurement of flow start temperature of liquid crystalline polyester]
Using a flow tester (“CFT-500 type” manufactured by Shimadzu Corporation), about 2 g of liquid crystal polyester was filled into a cylinder equipped with a die having a nozzle having an inner diameter of 1 mm and a length of 10 mm, and 9.8 MPa (100 kg). The liquid crystalline polyester was melted while being heated at a rate of 4 ° C./min under a load of / cm ² ), extruded from a nozzle, and a temperature showing a viscosity of 4800 Pa · s (48000 poise) was measured.

[Measurement of brightness of liquid crystal polyester]
Measurement was performed using a colorimetric color difference meter (“ZE-2000” manufactured by Nippon Denshoku Industries Co., Ltd.).

Example 1
In a reactor equipped with a stirrer, torque meter, nitrogen gas inlet tube, thermometer and reflux condenser, 994.5 g (7.2 mol) of p-hydroxybenzoic acid and 299.0 g (1.8 mol) of terephthalic acid 99.7 g (0.6 mol) of isophthalic acid, 446.9 g (2.4 mol) of 4,4′-dihydroxybiphenyl, 1298.6 g (12.7 mol) of acetic anhydride and 0.2 g of 1-methylimidazole Then, after replacing the gas in the reactor with nitrogen gas, the mixture was heated from room temperature to 150 ° C. over 30 minutes with stirring under a nitrogen gas stream, and refluxed at 150 ° C. for 1 hour. Next, 0.9 g of 1-methylimidazole was added and the temperature was increased from 150 ° C. to 320 ° C. over 2 hours and 50 minutes while distilling off by-product acetic acid and unreacted acetic anhydride, and an increase in torque was observed. At that time, the contents were removed from the reactor and cooled to room temperature. The obtained solid was pulverized by a pulverizer, heated from room temperature to 230 ° C. over 1 hour in a nitrogen atmosphere, heated from 230 ° C. to 260 ° C. over 2 hours, and heated at 260 ° C. for 10 hours. By holding, solid-phase polymerization was performed, followed by cooling to obtain a powdery liquid crystal polyester.

Table 1 shows the respective usage ratios (mol%) of p-hydroxybenzoic acid, terephthalic acid, isophthalic acid and 4,4′-dihydroxybiphenyl with respect to all raw material monomers. Further, Table 1 shows the use ratio (mole times) of acetic anhydride to the total amount of hydroxyl groups of p-hydroxybenzoic acid and 4,4′-dihydroxybiphenyl. In addition, Table 1 shows the flow start temperature of the obtained liquid crystal polyester. The lightness L ^* of the obtained liquid crystal polyester is shown in Table 1 together with the lightness L ^* before solid phase polymerization.

Examples 2 to 6, Comparative Examples 1 to 4
P-Hydroxybenzoic acid, terephthalic acid, isophthalic acid, and 4,4'-dihydroxybiphenyl used in proportion to the total amount of raw materials (mol%), p-hydroxybenzoic acid hydroxyl group and 4,4'-dihydroxybiphenyl hydroxyl The liquid crystal polyester was obtained in the same manner as in Example 1 except that the use ratio of acetic anhydride to the total amount of groups (mole times) and the upper limit of the solid-phase polymerization temperature were set to the values shown in Table 1. It was. Table 1 shows the flow start temperatures of the obtained liquid crystal polyester. The lightness L ^* of the obtained liquid crystal polyester is shown in Table 1 together with the lightness L ^* before solid phase polymerization.

Claims (21)

1. A repeating unit (1) derived from an aromatic hydroxycarboxylic acid, a repeating unit (2) derived from an aromatic dicarboxylic acid, and a repeating unit (3) derived from an aromatic diol, aromatic hydroxyamine or aromatic diamine, The content of the repeating unit (1) is 50 to 80 mol% based on the total amount of all the repeating units, and the content of the repeating unit (2) is the total amount of all the repeating units. And the content of the repeating unit (3) is 10 to 25 mol% with respect to the total amount of all repeating units, and the main chain has a 1,2-phenylene skeleton. Alternatively, a liquid crystal polyester in which the content of the repeating unit (A) containing a 1,3-phenylene skeleton is 5 to 30 mol% with respect to the total amount of all repeating units and the flow start temperature is 270 to 320 ° C.
2. The repeating unit (1) is a repeating unit derived from p-hydroxybenzoic acid or 6-hydroxy-2-naphthoic acid, and the repeating unit (2) is phthalic acid, isophthalic acid, terephthalic acid or 2,6 A repeating unit derived from naphthalenedicarboxylic acid, wherein the repeating unit (3) is catechol, resorcinol, hydroquinone, 4,4′-dihydroxybiphenyl, 2,6-naphthalenediol, o-aminophenol, m-aminophenol The liquid crystal polyester according to claim 1, which is a repeating unit derived from p-aminophenol, o-phenylenediamine, m-phenylenediamine or p-phenylenediamine.
3. The repeating unit (A) is a repeating unit derived from phthalic acid, isophthalic acid, catechol, resorcinol, o-aminophenol, m-aminophenol, o-phenylenediamine or m-phenylenediamine. Liquid crystalline polyester.
4. The liquid crystalline polyester according to claim 1, wherein the repeating unit (3) is a repeating unit derived from an aromatic diol.
5. The liquid crystalline polyester according to claim 1, wherein the content of the repeating unit containing a naphthalene ring is 0 to 30 mol% based on the total amount of all repeating units.
6. The liquid crystal polyester according to claim 1, wherein the lightness L ^* is 86 or more.
7. As the raw material monomer, an aromatic hydroxycarboxylic acid, an aromatic dicarboxylic acid, and at least one aromatic compound selected from the group consisting of an aromatic diol, an aromatic hydroxyamine, and an aromatic diamine are used. A step (1) of acylating a carboxylic acid and the aromatic compound with an acid anhydride to obtain an aromatic acyloxycarboxylic acid and an aromatic diacyl compound; and the aromatic acyloxycarboxylic acid, the aromatic diacyl compound, and the aromatic And a step (2) of obtaining a molten polymer by subjecting the aromatic dicarboxylic acid to a melt polymerization, and a step (3) of obtaining a solid-phase polymer by subjecting the molten polymer to a solid phase polymerization. The amount of the hydroxycarboxylic acid used is 50 to 80 mol% with respect to the total amount of all raw monomers, and the aromatic dicarboxylic acid The amount used is 10 to 25 mol% with respect to the total amount of all raw material monomers, the amount of the aromatic compound used is 10 to 25 mol% with respect to the total amount of all raw material monomers, The amount of the raw material monomer (A) containing a 1,2-phenylene skeleton or a 1,3-phenylene skeleton in the chain is 5 to 30 mol% with respect to the total amount of all raw material monomers, and the step (3) A method for producing a liquid crystal polyester, wherein the upper limit of the solid-state polymerization temperature in the solvent is 220 to 270 ° C.
8. The aromatic hydroxycarboxylic acid is at least one compound selected from the group consisting of p-hydroxybenzoic acid and 6-hydroxy-2-naphthoic acid, and the aromatic dicarboxylic acid is phthalic acid, isophthalic acid, terephthalic acid An at least one compound selected from the group consisting of acid and 2,6-naphthalenedicarboxylic acid, and the aromatic compound is catechol, resorcinol, hydroquinone, o-aminophenol, m-aminophenol, p-aminophenol, 8. The liquid crystal polyester according to claim 7, which is at least one compound selected from the group consisting of o-phenylenediamine, m-phenylenediamine, p-phenylenediamine, 4,4′-dihydroxybiphenyl and 2,6-naphthalenediol. Manufacturing method.
9. The raw material monomer (A) is at least one compound selected from the group consisting of phthalic acid, isophthalic acid, catechol, resorcinol, o-aminophenol, m-aminophenol, o-phenylenediamine and m-phenylenediamine. The method for producing a liquid crystal polyester according to claim 7.
10. The method for producing a liquid crystal polyester according to claim 7, wherein the aromatic compound is an aromatic diol.
11. The method for producing a liquid crystal polyester according to claim 7, wherein the amount of the raw material monomer containing a naphthalene ring is 0 to 30 mol% based on the total amount of all the raw material monomers.
12. The method for producing a liquid crystal polyester according to claim 7, wherein the acid anhydride is acetic anhydride.
13. The amount of the acid anhydride used is 1 to 1.1 mole times the hydroxyl group of the aromatic hydroxycarboxylic acid and the total amount of hydroxyl group and amino group of the aromatic compound. Manufacturing method of liquid crystal polyester.
14. The method for producing a liquid crystal polyester according to claim 7, wherein the step (1) and / or (2) is performed in the presence of a catalyst.
15. The method for producing a liquid crystal polyester according to claim 14, wherein the catalyst is an imidazole compound.
16. A liquid crystal polyester composition comprising the liquid crystal polyester according to claim 1 and a white pigment.
17. The liquid crystal polyester composition according to claim 16, wherein the white pigment is titanium oxide.
18. The liquid crystal polyester composition according to claim 16, wherein the content of the white pigment is 20 to 200 parts by mass with respect to 100 parts by mass of the liquid crystal polyester.
19. A reflector formed by molding the liquid crystal polyester composition according to claim 16.
20. A light emitting device comprising the reflector according to claim 19 and a light emitting element.
21. The light-emitting device according to claim 20, wherein the light-emitting element is an LED.