CN111936547A

CN111936547A - Liquid crystal polyester resin, method for producing same, and molded article formed from same

Info

Publication number: CN111936547A
Application number: CN201980023017.XA
Authority: CN
Inventors: 小西彬人; 宫本皓平; 梅津秀之
Original assignee: Toray Industries Inc
Current assignee: Toray Industries Inc
Priority date: 2018-04-13
Filing date: 2019-04-08
Publication date: 2020-11-13
Anticipated expiration: 2039-04-08
Also published as: JPWO2019198665A1; TW201943761A; TWI797308B; JP6652223B1; CN111936547B; WO2019198665A1; KR20200141991A; KR102644138B1

Abstract

A liquid crystal polyester resin comprising 15 to 80 mol% of a structural unit derived from an aromatic hydroxycarboxylic acid, 7 to 40 mol% of a structural unit derived from an aromatic diol, 7 to 40 mol% of a structural unit derived from an aromatic dicarboxylic acid, and 0.01 to 5 mol% of at least 1 structural unit selected from the following structural units (I) and (II) with respect to 100 mol% of the total structural units of the liquid crystal polyester resin. Provided are a liquid-crystalline polyester resin which is suppressed in mold contamination and is excellent in thin-wall fluidity and dimensional stability, and a molded article formed from the same.

Description

Liquid crystal polyester resin, method for producing same, and molded article formed from same

Technical Field

The present invention relates to a liquid crystal polyester resin and a molded article formed therefrom. More specifically, the present invention relates to a liquid crystal polyester resin which can provide a molded article having excellent flowability and dimensional stability while suppressing mold contamination during molding, and a molded article formed of the same.

Background

The liquid crystal polyester resin has a liquid crystal structure, and therefore is excellent in heat resistance, flowability, and dimensional stability. Therefore, there is an increasing demand for electrical and electronic components such as connectors and relays, which require these characteristics. In particular, with the recent increase in performance of devices, the size and thickness of the above-described members have been reduced, and flowability is further required. Therefore, for example, it has been proposed to improve the fluidity by obtaining a liquid crystal polymer having a low melt viscosity by melt-kneading a low molecular weight compound in the liquid crystal polymer (for example, see patent documents 1 and 2). As a method for changing the chemical type of the molecular skeleton of a liquid crystal polyester resin, a method has also been proposed in which the fluidity is improved by a liquid crystal polyester amide containing a structure derived from acetaminophenone and 1, 4-cyclohexanedicarboxylic acid (for example, see patent document 3).

Documents of the prior art

Patent document

Patent document 1: japanese Kohyo publication No. 2002-511513

Patent document 2: japanese patent laid-open publication No. 2018-44108

Patent document 3: international publication No. 2013/115168

Disclosure of Invention

Problems to be solved by the invention

On the other hand, when the liquid crystal polyester resin is made to have a low melt viscosity by the methods described in patent documents 1 and 2, the low molecular weight compound itself used has low heat resistance, and therefore, the low molecular weight compound decomposes at a high processing temperature required for molding the liquid crystal polyester resin to increase gas, and the mold is contaminated during molding, and in addition, there is a problem that dimensional stability is lowered. Further, the thin-wall fluidity is not sufficient. Further, the liquid crystal polyester amide resin described in patent document 3 also has problems of mold contamination and dimensional stability, and is insufficient in thin-wall fluidity.

The present invention addresses the above-described problems and provides a liquid crystal polyester resin which can provide a molded article having excellent flowability and dimensional stability while suppressing mold contamination during molding, and a molded article thereof.

Means for solving the problems

The present inventors have made intensive studies to solve the above problems, and as a result, have found that a molded article having excellent flowability and dimensional stability while suppressing mold contamination at the time of molding can be obtained by a liquid crystal polyester resin containing a specific structural unit in a small amount, and have completed the present invention.

The invention is as follows:

(1) a liquid crystal polyester resin comprising 15 to 80 mol% of a structural unit derived from an aromatic hydroxycarboxylic acid, 7 to 40 mol% of a structural unit derived from an aromatic diol, 7 to 40% of a structural unit derived from an aromatic dicarboxylic acid, and 0.01 to 5 mol% of at least 1 structural unit selected from the following structural units (I) and (II) with respect to 100 mol% of the total structural units of the liquid crystal polyester resin.

(2) The liquid-crystalline polyester resin according to the item (1), wherein the structural unit derived from an aromatic hydroxycarboxylic acid comprises a structural unit (III), and the structural unit derived from an aromatic dicarboxylic acid comprises a structural unit (IV), and the total of the structural unit (III) and the structural unit (IV) is 60 to 80 mol% based on 100 mol% of the total structural units of the liquid-crystalline polyester resin.

(3) The liquid crystal polyester resin according to (1) or (2), wherein the structural unit derived from an aromatic diol in the liquid crystal polyester resin comprises the following structural unit (V), and the structural unit (V) is 2 to 20% by mole with respect to 100% by mole of the total structural units of the liquid crystal polyester resin.

(4) The liquid-crystalline polyester resin according to any one of (1) to (3), wherein at least 1 structural unit selected from the structural unit (I) and the structural unit (II) contains the structural unit (II) as an essential component.

(5) The liquid-crystalline polyester resin according to any one of (1) to (4), which is obtained by blending a liquid-crystalline polyester resin not containing a structural unit selected from the structural unit (I) and the structural unit (II), and a compound having at least 1 structure selected from the structural unit (I) and the structural unit (II).

(6) The process for producing a liquid-crystalline polyester resin according to any one of (1) to (5), wherein a liquid-crystalline polyester not containing a structural unit selected from the structural unit (I) and the structural unit (II), and a compound having at least 1 structure selected from the structural unit (I) and the structural unit (II) are melt-kneaded.

(7) A liquid crystal polyester resin composition comprising 10 to 200 parts by weight of a filler per 100 parts by weight of the liquid crystal polyester resin according to any one of (1) to (5).

(8) A molded article comprising the liquid crystal polyester resin according to any one of (1) to (5) or the liquid crystal polyester resin composition according to (7).

(9) The molded article according to (8), which is selected from the group consisting of a connector, a relay, a switch, a bobbin, a lamp holder, a camera module, and an integrated circuit sealing material.

ADVANTAGEOUS EFFECTS OF INVENTION

According to the liquid crystal polyester resin of the present invention, a molded article having excellent flowability and dimensional stability can be obtained while suppressing mold contamination during molding. Such a resin is particularly suitable for electrical/electronic parts and mechanical parts such as thin-walled box-shaped and cylindrical connectors, relays, switches, coil holders, lamp sockets, camera modules, and integrated circuit sealing materials.

Drawings

Fig. 1 is a perspective view showing a connector molded article produced in the example and a conceptual view showing a measurement portion of a warpage amount.

Detailed Description

The present invention will be described in detail below.

< liquid Crystal polyester resin >

The liquid crystal polyester resin used in the present invention is a polyester forming an anisotropic melt phase. Examples of the liquid crystal polyester resin include polyesters composed of structural units selected from oxycarbonyl units, dioxy units, dicarbonyl units, and the like, which will be described later, so as to form an anisotropic melt phase.

Next, a structural unit constituting the liquid crystal polyester resin will be explained.

The liquid-crystalline polyester resin of the present invention contains 15 to 80 mol% of an oxycarbonyl unit, that is, a structural unit derived from an aromatic hydroxycarboxylic acid, relative to 100 mol% of the total structural units of the liquid-crystalline polyester resin. If the content of the oxycarbonyl unit is less than 15 mol%, liquid crystallinity is impaired, and thus flowability of the liquid crystal polyester resin is reduced and dimensional stability is also reduced. The content of the oxycarbonyl unit is preferably 20 mol% or more, and more preferably 25 mol% or more from the viewpoint of improving fluidity and dimensional stability. On the other hand, if the content of the oxycarbonyl unit is more than 80 mol%, it becomes difficult to control the crystallinity and the melting point of the liquid-crystalline polyester resin, and the fluidity and the dimensional stability are lowered. The content of the oxycarbonyl unit is preferably 75 mol% or less, more preferably 70 mol% or less, from the viewpoint of improving fluidity and dimensional stability.

Specific examples of the oxycarbonyl unit include structural units derived from p-hydroxybenzoic acid, m-hydroxybenzoic acid, 6-hydroxy-2-naphthoic acid and the like.

The liquid crystal polyester resin of the present invention contains a structural unit derived from an aromatic diol, which is a dioxy unit, in an amount of 7 to 40 mol% based on 100 mol% of all structural units of the liquid crystal polyester resin. If the content of the dioxy unit is less than 5 mol%, it becomes difficult to control the crystallinity and melting point of the liquid-crystalline polyester resin, and the fluidity and dimensional stability are lowered. The content of the dioxy unit is preferably 10 mol% or more, and more preferably 15 mol% or more, from the viewpoint of improving fluidity and dimensional stability. On the other hand, if the content of the dioxy unit is more than 40 mol%, the liquid crystallinity is impaired, and thus the fluidity of the liquid crystal polyester resin is reduced and the dimensional stability is also reduced. The content of the dioxy unit is preferably 37 mol% or less, and more preferably 35 mol% or less, from the viewpoint of improving fluidity and dimensional stability.

The liquid crystal polyester resin of the present invention contains, as a dioxy unit, at least 1 structural unit selected from the following structural units (I) and (II) in an amount of 0.01 to 5 mol% based on 100 mol% of all the structural units of the liquid crystal polyester resin, in addition to the structural units derived from the aromatic diol in the above-described amount. The structural unit (I) and the structural unit (II) are structural units derived from 1, 4-cyclohexanediol and 1, 4-cyclohexanedimethanol, respectively. If the content of these structural units is less than 0.01 mol%, the thin-wall fluidity and the dimensional stability are lowered. The content of these structural units is preferably 0.03 mol% or more, and more preferably 0.05 mol% or more, from the viewpoint of excellent thin-wall fluidity and dimensional stability. On the other hand, if the content of these structural units exceeds 5 mol%, mold contamination occurs during molding, and the thin-wall fluidity and dimensional stability are also reduced. The content of these structural units is preferably 3% or less, more preferably 1% or less, from the viewpoint of suppressing mold contamination during molding and also excellent thin-wall fluidity and dimensional stability. The structural unit (I) and the structural unit (II) may have either one and the other is 0 mol%, but from the viewpoint of suppressing mold contamination at the time of molding and being excellent in thin-wall fluidity and dimensional stability, it is preferable to contain the structural unit (II) as an essential component.

Examples of the structural unit derived from an aromatic diol include structural units derived from 4,4 '-dihydroxybiphenyl, hydroquinone, resorcinol, tert-butylhydroquinone, phenylhydroquinone, chlorohydroquinone, 2, 6-dihydroxynaphthalene, 2, 7-dihydroxynaphthalene, 3, 4' -dihydroxybiphenyl, 2-bis (4-hydroxyphenyl) propane, 4 '-dihydroxydiphenyl ether, 4' -dihydroxydiphenyl sulfone, 4 '-dihydroxydiphenyl sulfide, 4' -dihydroxybenzophenone, and the like. From the viewpoint of suppressing mold contamination during molding and having excellent fluidity and dimensional stability, it is preferable to use a structural unit selected from structural units derived from 4, 4' -dihydroxybiphenyl and hydroquinone. Further, the liquid crystal composition may further contain a structural unit derived from an aliphatic diol such as ethylene glycol, propylene glycol, 1, 4-butanediol, 1, 6-hexanediol, or neopentyl glycol, within a range not to impair liquid crystallinity or characteristics.

The liquid-crystalline polyester resin of the present invention contains 7 to 40 mol% of a structural unit derived from an aromatic dicarboxylic acid as a dicarbonyl unit with respect to 100 mol% of the total structural units of the liquid-crystalline polyester resin. If the content of the structural unit derived from the aromatic dicarboxylic acid is less than 7 mol%, it becomes difficult to control the crystallinity and the melting point of the liquid-crystalline polyester resin, and the fluidity and the dimensional stability are lowered. The content of the structural unit derived from the aromatic dicarboxylic acid is preferably 10 mol% or more, and more preferably 15 mol% or more, from the viewpoint of improving the flowability and dimensional stability. On the other hand, if the content of the structural unit derived from an aromatic dicarboxylic acid is more than 40 mol%, the liquid crystallinity is impaired, and therefore the fluidity of the liquid-crystalline polyester resin is reduced and the dimensional stability is also reduced. The content of the structural unit derived from an aromatic dicarboxylic acid is preferably 37 mol% or less, and more preferably 35 mol% or less, from the viewpoint of improving fluidity and dimensional stability.

Examples of the structural unit derived from an aromatic dicarboxylic acid include structural units derived from terephthalic acid, isophthalic acid, 2, 6-naphthalenedicarboxylic acid, 4 '-biphenyldicarboxylic acid, 3' -biphenyldicarboxylic acid, 2 '-biphenyldicarboxylic acid, 1, 2-bis (phenoxy) ethane-4, 4' -dicarboxylic acid, 1, 2-bis (2-chlorophenoxy) ethane-4, 4 '-dicarboxylic acid, and 4, 4' -diphenyletherdicarboxylic acid. From the viewpoint of suppressing mold contamination during molding and having excellent flowability and dimensional stability, it is preferable to use a structural unit selected from structural units derived from terephthalic acid and isophthalic acid. In addition, the liquid crystal composition may further include a structural unit derived from an aliphatic dicarboxylic acid such as adipic acid, azelaic acid, sebacic acid, dodecanedioic acid, hexahydroterephthalic acid, or the like, a structural unit derived from an alicyclic dicarboxylic acid such as 1, 4-cyclohexanedicarboxylic acid, 1, 3-cyclohexanedicarboxylic acid, or the like, in a range not to impair liquid crystallinity and characteristics.

In addition to the above-mentioned structural units, structural units derived from p-aminobenzoic acid, p-aminophenol, or the like may be further included within a range not impairing the liquid crystallinity and the characteristics.

The raw material monomer constituting each of the above-mentioned structural units is not particularly limited as long as it is a structure capable of forming each structural unit, and an acyl compound of a hydroxyl group of each structural unit, an ester compound of a carboxyl group of each structural unit, an acid halide compound, a carboxylic acid derivative such as an acid anhydride, or the like can be used.

In the liquid-crystalline polyester resin of the present invention, it is preferable that the structural unit derived from an aromatic hydroxycarboxylic acid comprises the following structural unit (III), the structural unit derived from an aromatic dicarboxylic acid comprises the following structural unit (IV), and the total content of the structural unit (III) and the structural unit (IV) is 60 to 80 mol% with respect to 100 mol% of the total structural units of the liquid-crystalline polyester resin. From the viewpoint of controlling crystallinity and melting point of the liquid-crystalline polyester resin, and of excellent thin-wall flowability and dimensional stability, the total content of the structural unit (III) and the structural unit (IV) is preferably 63 mol% or more, and more preferably 67 mol% or more. On the other hand, the total content of the structural unit (III) and the structural unit (IV) is preferably 78 mol% or less from the viewpoint of excellent thin-wall fluidity and dimensional stability while controlling the crystallinity and melting point of the liquid-crystalline polyester resin. In addition, the structural unit (III) and the structural unit (IV) may have either one structural unit and the other structural unit is 0 mol%, but from the viewpoint of controlling crystallinity and melting point of the liquid crystal polyester resin, it is preferable to contain both more than 0 mol%.

From the viewpoint of excellent thin-wall flowability and dimensional stability, the content of the structural unit (III) is preferably 30 mol% or more, and more preferably 50 mol% or more, based on 100 mol% of the total structural units of the liquid-crystalline polyester resin. On the other hand, the content of the structural unit (III) is preferably 70 mol% or less, and preferably 65 mol% or less, from the viewpoint of controlling the crystallinity and melting point of the liquid-crystalline polyester resin, and further, excellent thin-wall fluidity and dimensional stability.

From the viewpoint of excellent thin-wall flowability and dimensional stability, the content of the structural unit (IV) is preferably 5 mol% or more, and preferably 10 mol% or more, based on 100 mol% of the total structural units of the liquid-crystalline polyester resin. On the other hand, the content of the structural unit (IV) is preferably 30 mol% or less, and preferably 20 mol% or less, from the viewpoint of excellent thin-wall fluidity and dimensional stability.

In the liquid crystal polyester resin of the present invention, it is preferable that the structural unit derived from an aromatic diol comprises the following structural unit (V) in an amount of 2 to 20 mol% based on 100 mol% of the total amount of the structural units of the liquid crystal polyester resin. The structural unit (V) is a structural unit derived from hydroquinone. By containing the structural unit (V) in an amount of 2 mol% or more, the thin-wall fluidity and the dimensional stability can be further improved. The content of the structural unit (V) is more preferably 4 mol% or more, and still more preferably 7.5 mol% or more. On the other hand, by containing 20 mol% or less of the structural unit (V), the thin-wall fluidity and the dimensional stability can be further improved. The content of the structural unit (V) is more preferably 15 mol% or less, and still more preferably 12 mol% or less.

In the liquid crystal polyester resin of the present invention, the structural unit derived from an aromatic diol preferably contains the following structural unit (VI) in an amount of 3 to 30 mol% based on 100 mol% of the total amount of the structural units of the liquid crystal polyester resin. The structural unit (VI) is a structural unit derived from 4, 4' -dihydroxybiphenyl. By containing the structural unit (VI) in an amount of 3 mol% or more, the crystallinity and melting point of the liquid crystal polyester resin can be controlled, and the heat resistance can be improved. The content of the structural unit (VI) is preferably 5 mol% or more, and more preferably 7 mol% or more. On the other hand, by containing 30 mol% or less of the structural unit (VI), the crystallinity and melting point of the liquid crystal polyester resin can be controlled, and the moldability can be improved. The content of the structural unit (VI) is more preferably 25 mol% or less, and still more preferably 20 mol% or less.

In the liquid-crystalline polyester resin of the present invention, the structural unit derived from an aromatic dicarboxylic acid preferably contains the following structural unit (VII) in an amount of 1 to 10 mol% based on 100 mol% of the total amount of the structural units of the liquid-crystalline polyester resin. The following structural unit (VII) is a structural unit derived from isophthalic acid. By containing the structural unit (VII) in an amount of 1 mol% or more, the crystallinity and melting point of the liquid-crystalline polyester resin can be controlled, and the moldability can be improved. The content of the structural unit (VII) is preferably 2 mol% or more, and more preferably 3 mol% or more. On the other hand, by containing the structural unit (VII) in an amount of 10 mol% or less, the crystallinity and melting point of the liquid crystal polyester resin can be controlled, and the heat resistance can be improved. The content of the structural unit (VII) is more preferably 9 mol% or less, and still more preferably 8 mol% or less.

The content of each structural unit in the liquid crystal polyester resin of the present invention can be determined by pulverizing liquid crystal polyester particles, adding tetramethylammonium hydroxide, and measuring by thermal decomposition GC/MS using GCMS-QP5050A manufactured by Shimadzu corporation. The content of the structural unit which is not detected or is not more than the detection limit is calculated as 0 mol%.

From the viewpoint of heat resistance, the melting point (Tm) of the liquid crystal polyester resin of the present invention is preferably 220 ℃ or higher, more preferably 270 ℃ or higher, and still more preferably 300 ℃ or higher. On the other hand, the melting point (Tm) of the liquid crystal polyester resin is preferably 360 ℃ or less, more preferably 355 ℃ or less, and even more preferably 350 ℃ or less, from the viewpoint of suppressing deterioration of the liquid crystal polyester resin during processing and suppressing mold contamination during molding.

The melting point (Tm) is measured by differential scanning calorimetry. Specifically, first, the polymer after completion of polymerization was heated from room temperature under a temperature rise condition of 20 ℃ per minute to observe the endothermic peak temperature (Tm)₁). At the endothermic peak temperature (Tm)₁) After observation, at the endothermic peak temperature (Tm)₁) The polymer was held at a temperature of +20 ℃ for 5 minutes. Then, the polymer was cooled to room temperature at a temperature decrease of 20 ℃ per minute. Further, the polymer was heated again under a temperature rise condition of 20 ℃ per minute to observe the endothermic peak temperature (Tm)₂). The melting point (Tm) is the endothermic peak temperature (Tm) in the 2 nd temperature rise process₂)。

From the viewpoint of suppressing mold contamination at the time of molding, the melt viscosity of the liquid crystal polyester resin of the present invention is preferably 1Pa · s or more, more preferably 3Pa · s or more, and further preferably 5Pa · s or more. On the other hand, the melt viscosity of the liquid crystal polyester resin is preferably 50Pa · s or less, preferably 20Pa · s or less, and more preferably 10Pa · s or less, from the viewpoint of excellent thin-wall fluidity.

The melt viscosity is a value measured by an advanced flow tester at a temperature of the melting point (Tm) +20 ℃ of the liquid crystal polyester resin and at a shear rate of 1000/sec.

< method for producing liquid-crystalline polyester resin >

The following methods can be mentioned as methods for producing the liquid-crystalline polyester resin used in the present invention.

(A) A method of adding a compound having at least 1 structure selected from the structural unit (I) and the structural unit (II) in the production by a known polycondensation method of a polyester described later.

(B) A method of producing a liquid crystal polyester resin not containing a structural unit selected from the structural unit (I) and the structural unit (II) according to a known polycondensation method of polyester described later, and then blending a compound having at least 1 structure selected from the structural unit (I) and the structural unit (II).

Since mold contamination during molding can be suppressed and thin-wall fluidity and dimensional stability can be further improved by an appropriate transesterification reaction with the liquid crystal polyester resin, (B) a method of preparing a liquid crystal polyester resin not containing a structural unit selected from the structural unit (I) and the structural unit (II) and then adding a compound having at least 1 structure selected from the structural unit (I) and the structural unit (II) is preferable. The method of blending them is preferably a method of melt-kneading them. The detailed production method will be described later.

Examples of the compound having at least 1 structure selected from the structural unit (I) and the structural unit (II) include 1, 4-cyclohexanediol, 1, 4-cyclohexanedimethanol, and a compound obtained by ester-bonding 1 or more structural units capable of constituting a liquid crystal polyester resin, such as an oxycarbonyl unit and a dicarbonyl unit, to the diol compound. Among them, from the viewpoint of suppressing mold contamination at the time of molding, preferred are 1, 4-cyclohexanediol having 2 hydroxyl groups, 1, 4-cyclohexanedimethanol, and a compound obtained by ester-bonding 1 or more oxycarbonyl units capable of constituting a liquid crystal polyester resin to the above diol compound. Further, from the viewpoint of high heat resistance, suppression of mold contamination during molding due to suppression of thermal decomposition during polycondensation and melt kneading, and excellent thin-wall fluidity and dimensional stability, a compound obtained by ester-bonding 1 or more oxycarbonyl units capable of constituting a liquid crystal polyester resin with the diol compound is more preferable, and a compound obtained by ester-bonding 2 or more oxycarbonyl units capable of constituting a liquid crystal polyester resin with the diol compound is particularly preferable. The compound may further contain an oxycarbonyl unit in the vicinity of the oxycarbonyl unit, but the upper limit of the number of bonded oxycarbonyl units is preferably 10 or less, more preferably 7 or less, from the viewpoint of not generating a long-chain infusible material derived from a rigid oxycarbonyl unit.

Examples of the compounds obtained by ester-bonding 1 or more oxycarbonyl units capable of constituting a liquid crystal polyester resin with the above diol compound include cyclohexane-1, 4-diylbis (methylene) bis (4-hydroxybenzoate), (4- (hydroxymethyl) cyclohexyl) methyl 4-hydroxybenzoate, 4-hydroxycyclohexyl 4-hydroxybenzoate, cyclohexane-1, 4-diylbis (4-hydroxybenzoate) and the like.

These compounds can be produced by esterifying 1, 4-cyclohexanediol or 1, 4-cyclohexanedimethanol with an aromatic hydroxycarboxylic acid by a method known to those skilled in the art, for example, the method described in Japanese patent application laid-open No. 2008-544954. Specifically, a compound obtained by ester-bonding 1 or more oxycarbonyl units capable of constituting a liquid crystal polyester resin to the diol compound can be obtained by reacting 1, 4-cyclohexanediol or 1, 4-cyclohexanedimethanol with an aromatic hydroxycarboxylic acid in a solvent under reflux with heating in the presence of sulfuric acid, and then washing with methanol to purify the product.

From the viewpoint of suppressing mold contamination during molding and having excellent thin-wall fluidity and dimensional stability, the molecular weight of the compound having at least 1 structure selected from the structural unit (I) and the structural unit (II) is preferably 200 or more, more preferably 230 or more, and still more preferably 250 or more. On the other hand, in the case of a compound obtained by ester-bonding 1 or more structural units capable of constituting the liquid crystal polyester resin with a diol compound, the molecular weight is preferably 1000 or less, more preferably 700 or less, and even more preferably 500 or less, from the viewpoint of suppressing the generation of infusions due to long chains of rigid structural units.

In the case of producing a liquid crystal polyester resin by the method of the above (B), in order to set the content of at least 1 selected from the structural unit (I) and the structural unit (II) within a desired range, it is preferable to add a compound having at least 1 structure selected from the structural unit (I) and the structural unit (II) preferably at least 0.01 part by weight, more preferably at least 0.03 part by weight, and still more preferably at least 0.05 part by weight, to 100 parts by weight of a liquid crystal polyester resin not containing the structural unit selected from the structural unit (I) and the structural unit (II). On the other hand, it is preferable that the compound having at least 1 structure selected from the structural unit (I) and the structural unit (II) is blended with preferably 10 parts by weight or less, more preferably 7 parts by weight or less, and further preferably 3 parts by weight or less, per 100 parts by weight of the liquid crystal polyester resin not containing the structural unit selected from the structural unit (I) and the structural unit (II).

As a known polycondensation method of a polyester, a liquid crystal polyester resin composed of a structural unit derived from p-hydroxybenzoic acid, a structural unit derived from 4, 4' -dihydroxybiphenyl, a structural unit derived from hydroquinone, a structural unit derived from terephthalic acid, and a structural unit derived from isophthalic acid is exemplified by the following method.

(1) A process for producing a liquid-crystalline polyester resin from p-acetoxybenzoic acid, 4' -diacetoxybiphenyl, diacetoxybenzene, terephthalic acid and isophthalic acid by a deacetic acid polycondensation reaction.

(2) A method for producing a liquid crystal polyester resin, which comprises reacting acetic anhydride with p-hydroxybenzoic acid, 4' -dihydroxybiphenyl, hydroquinone, terephthalic acid, and isophthalic acid to acetylate the phenolic hydroxyl groups, and then subjecting the resultant to a polymerization with removal of acetic acid.

(3) A method for producing a liquid-crystalline polyester resin from phenyl parahydroxybenzoate, 4' -dihydroxybiphenyl, hydroquinone, diphenyl terephthalate and diphenyl isophthalate by dephenolization polycondensation.

(4) A method for producing a liquid-crystalline polyester resin by reacting a predetermined amount of diphenyl carbonate with p-hydroxybenzoic acid, terephthalic acid and isophthalic acid to produce phenyl esters, and then adding 4, 4' -dihydroxybiphenyl and hydroquinone to the phenyl esters to conduct a dephenolization polycondensation reaction.

Among them, from the viewpoint that the control of the terminal structure and the control of the polymerization degree of the liquid crystal polyester resin are industrially excellent, (2) a method of producing a liquid crystal polyester resin by reacting acetic anhydride with p-hydroxybenzoic acid, 4' -dihydroxybiphenyl, hydroquinone, terephthalic acid, and isophthalic acid to acetylate the phenolic hydroxyl group, and then performing a deacetylation polycondensation reaction is preferably used.

As a method for producing a liquid crystal polyester resin, a polycondensation reaction can be completed by a solid phase polymerization method. Examples of the solid-phase polymerization method include the following methods. First, a polymer or oligomer of the liquid crystal polyester resin is pulverized by a pulverizer. The pulverized polymer or oligomer is heated under nitrogen flow or under reduced pressure to perform polycondensation to a desired degree of polymerization, thereby completing the reaction. The heating may be performed for 1 to 50 hours in a range of a melting point of the liquid crystal polyester from-50 ℃ to-5 ℃ (for example, 200 to 300 ℃).

The polycondensation reaction of the liquid-crystalline polyester resin is also carried out without a catalyst, but stannous acetate, tetrabutyl titanate, potassium acetate, sodium acetate, antimony trioxide, metallic magnesium, or the like may be used as a catalyst.

< liquid crystal polyester resin composition >

The liquid crystal polyester resin of the present invention may be used as a resin composition containing a filler in order to impart mechanical strength and other properties to the liquid crystal polyester resin. The filler is not particularly limited, and examples thereof include a fibrous filler, a whisker-like filler, a plate-like filler, a powder-like filler, and a granular filler. Specifically, examples of the fibrous filler and the whisker-like filler include glass fibers; PAN-based or pitch-based carbon fibers; metal fibers such as stainless steel fibers, aluminum fibers, brass fibers, and the like; organic fibers such as aromatic polyamide fibers and liquid crystal polyester fibers; gypsum fibers, ceramic fibers, asbestos fibers, zirconia fibers, alumina fibers, silica fibers, titanium oxide fibers, silicon carbide fibers, rock wool, potassium titanate whiskers, barium titanate whiskers, aluminum borate whiskers, silicon nitride whiskers, needle-like titanium oxide, and the like. Examples of the plate-like filler include mica, talc, kaolin, glass flake, clay, molybdenum disulfide, wollastonite, and the like. Examples of the powdery filler and the particulate filler include silica, glass beads, titanium oxide, zinc oxide, calcium polyphosphate, graphite, and the like. The surface of the filler may be treated with a known coupling agent (e.g., a silane coupling agent, a titanate coupling agent, etc.) or other surface treatment agent. The filler may be used in combination of 2 or more.

Among the fillers, glass fibers are particularly preferable because they are excellent in mechanical strength such as tensile strength and flexural strength, heat resistance, and dimensional stability. The type of the glass fiber is not particularly limited as long as it is a type generally used for reinforcement of resins, and examples thereof include long-fiber type, short-fiber type chopped strands, and milled fibers. Mica is preferably used because of its excellent thin-wall fluidity.

The surface of the filler may be treated with a known coupling agent (e.g., a silane coupling agent, a titanate coupling agent, etc.) or other surface treatment agent. The glass fibers may be coated or bundled with a thermoplastic resin such as an ethylene/vinyl acetate copolymer or a thermosetting resin such as an epoxy resin.

The content of the filler is preferably 10 to 200 parts by weight based on 100 parts by weight of the liquid crystal polyester resin. It is preferable that the content of the filler is 10 parts by weight or more because the mechanical strength of the molded article can be improved. More preferably 15 parts by weight or more, and still more preferably 20 parts by weight or more. On the other hand, if the filler content is 200 parts by weight or less, a liquid crystal polyester resin composition excellent in moldability and thin-wall fluidity can be obtained, and therefore, it is preferable. More preferably 150 parts by weight or less, and still more preferably 100 parts by weight or less.

The liquid crystal polyester resin composition of the present invention may further contain a conventional additive selected from an antioxidant, a heat stabilizer (e.g., hindered phenol, hydroquinone, phosphite, thioether, and a substituted product thereof), an ultraviolet absorber (e.g., resorcinol, salicylate), a phosphite, a coloring inhibitor such as hypophosphite, a lubricant, a mold release agent (e.g., montanic acid and a metal salt thereof, an ester thereof, a half ester thereof, stearyl alcohol, stearamide, and polyethylene wax), a colorant containing a dye or pigment, carbon black as a conductive agent or a colorant, a crystal nucleating agent, a plasticizer, a flame retardant (e.g., a bromine flame retardant, a phosphorus flame retardant, red phosphorus, and a silicone flame retardant), a flame retardant auxiliary, and an antistatic agent, as long as the effects of the present invention are not impaired.

< method for producing liquid crystal polyester resin composition >

As a method for obtaining the liquid crystal polyester resin composition of the present invention, for example: a dry blending method in which a compound having at least 1 structure selected from the structural unit (I) and the structural unit (II), a filler, other solid additives, and the like are blended into a liquid crystal polyester resin not containing a structural unit selected from the structural unit (I) and the structural unit (II); a solution compounding method of compounding a liquid crystal polyester resin not containing a structural unit selected from the structural unit (I) and the structural unit (II), a compound having at least 1 structure selected from the structural unit (I) and the structural unit (II), a filler, other liquid additives, and the like; a method in which a compound having at least 1 structure selected from the structural unit (I) and the structural unit (II), a filler, and other additives are added at the time of polymerization of a liquid crystal polyester resin not containing a structural unit selected from the structural unit (I) and the structural unit (II); a method of melt-kneading a liquid crystal polyester resin not containing a structural unit selected from the structural unit (I) and the structural unit (II), a compound having at least 1 structure selected from the structural unit (I) and the structural unit (II), a filler, and other additives. Among them, a method of melt kneading is preferable. The melt kneading may be carried out by a known method. For example, the liquid crystal polyester resin composition can be obtained by melt-kneading the above components at the melting point of the liquid crystal polyester resin +50 ℃ or lower using a banbury mixer, a rubber roll, a kneader, a single-screw or twin-screw extruder, or the like. Among them, melt kneading using a twin-screw extruder is preferable.

In the twin-screw extruder, in order to improve the dispersibility of the liquid crystal polyester resin and the filler, the kneading section 1 or more is preferably provided, and the kneading section 2 or more is more preferably provided. In the case of producing a liquid crystal polyester resin by the method of the above (B), by providing the kneading section as described above, the dispersibility of the liquid crystal polyester resin not containing the structural unit selected from the structural unit (I) and the structural unit (II) and the compound having at least 1 structure selected from the structural unit (I) and the structural unit (II) is improved, and the both are subjected to an ester exchange reaction appropriately, whereby the mold contamination at the time of molding can be suppressed, and the thin wall fluidity and the dimensional stability can be further improved. In the case where the filler is added from the side inlet, for example, the position of the kneading portion is preferably 1 or more on the upstream side of the side inlet of the filler in order to promote plasticization of the liquid crystal polyester resin, and 2 or more in total on the downstream side of the side inlet in order to improve dispersibility of the liquid crystal polyester resin and the filler, on the upstream side of the side inlet, in the range of 1 or more.

In addition, in order to remove moisture and decomposition products generated during kneading in the twin-screw extruder, it is preferable to provide a vent portion. In the case where the filler is added from the side inlet, for example, the position of the vent is preferably 1 or more on the upstream side of the side inlet into which the filler is charged in order to remove moisture adhering to the liquid crystal polyester resin, and 2 or more in total on the downstream side of the side inlet in order to remove decomposition gas during melt kneading and entrained air during supply of the filler, 1 or more. The vent portion may be under normal pressure or under reduced pressure.

Examples of the kneading method include: (1) a method in which a liquid crystal polyester resin not containing a structural unit selected from the structural unit (I) and the structural unit (II), a compound having at least 1 structure selected from the structural unit (I) and the structural unit (II), a filler, and other additives are collectively fed from a main feed port and kneaded (collective kneading method); (2) a method in which a liquid crystal polyester resin not containing a structural unit selected from the structural unit (I) and the structural unit (II), a compound having at least 1 structure selected from the structural unit (I) and the structural unit (II), and another additive are fed from a main feed port and kneaded, and then a filler and another additive are added from a side feed port and kneaded (side feed method); (3) a method (mother particle method) in which a mother particle containing a liquid crystal polyester resin containing no structural unit selected from the structural unit (I) and the structural unit (II), a compound having at least 1 structure selected from the structural unit (I) and the structural unit (II), and other additives at a high concentration is prepared, and then the mother particle is kneaded with the liquid crystal polyester resin and a filler so as to have a predetermined concentration. Any method may be used.

The liquid crystal polyester resin composition of the present invention can be processed into a molded article having excellent surface appearance (color tone), mechanical properties, heat resistance and flame retardancy by performing known melt molding such as injection molding, injection compression molding, extrusion molding, blow molding, press molding, spinning and the like. Examples of the molded article include various films such as injection molded articles, extrusion molded articles, press molded articles, sheets, tubes, unstretched films, uniaxially stretched films and biaxially stretched films, and various fibers such as unstretched yarns and super-stretched yarns. In particular, injection molded articles are preferable from the viewpoint of processability.

The molded article obtained by molding the liquid crystal polyester resin or the liquid crystal polyester composition of the present invention can be used for electric/electronic components typified by various gears, various housings, sensors, LED lamps, connectors, sockets, resistors, relay housings, bobbins, switches, bobbins, camera modules, capacitors, variable capacitor housings, optical pickup devices, resonators, various terminal boards, transformers, plugs, printed wiring boards, tuners, speakers, microphones, headphones, small motors, head units, power modules, housings, semiconductors, integrated circuit sealing materials, liquid crystal display components, FDD brackets, FDD chassis, HDD components, motor brush holders, parabolic antennas, computer-related components, and the like; voice equipment components such as VTR component, TV component, iron, hair drier, electric cooker component, microwave oven component, sound component, audio/laser disc/optical disc, etc.; household and office electric product parts typified by lighting parts, refrigerator parts, air conditioner parts, personal computer parts, and the like; machine-related parts typified by office computer-related parts, telephone-related parts, facsimile-related parts, copier-related parts, various bearings such as washing jigs, oilless bearings, stern bearings, and water bearings, and motor parts; optical devices and precision machine-related parts typified by microscopes, binoculars, cameras, clocks, and the like; alternator terminals, alternator connectors, IC regulators, dimmer potentiometers, exhaust valves and other valves, fuel-related/exhaust/intake pipes, intake nozzle snorkels, intake manifolds, fuel pumps, engine cooling water connections, carburetor bodies, carburetor spacers, exhaust gas sensors, cooling water sensors, oil temperature sensors, throttle position sensors, crank position sensors, air flow meters, brake pad wear sensors, air conditioner thermostat bases, air conditioner motor insulators, electric window and other vehicle-mounted motor insulators, warm house warm air flow control valves, radiator motor brush holders, water pump impellers, turbine blades, wiper motor-related parts, dispensers, starter switches, starter relays, transmission wiring, window washer nozzle tips, and other components, Automobile/vehicle-related components such as an air conditioner panel switch substrate, a coil for a fuel-related solenoid valve, a connector for a fuse, a horn terminal, an electric component insulating plate, a stepping motor rotor, a lamp frame, a lamp socket, a lamp reflector, a lamp housing, a brake piston, a solenoid spool, an engine oil filter, and an ignition device housing; various medicine bottles such as shampoo, hair conditioner, liquid soap, and lotion; liquid/gas storage tanks such as a liquid storage tank, a gas storage tank, a cooling liquid tank, an oil transfer tank, a disinfectant tank, a transfusion pump tank, a fuel tank, a scrubber liquid tank, and an oil storage tank; a medical device use component; food preservation containers for sauces, ketchup, mayonnaise, sauces and other seasonings, miso, vinegar and other fermented foods, salad oil and other fat foods, sake, beer, sweet cooking wine, whiskey, distilled spirit, wine and other alcoholic beverages, carbonated beverages, fruit juice, sports beverages, milk, coffee beverages, oolong tea, black tea, mineral water and other refreshing drinking water; and a can or a bottle-shaped molded article as a component of a general household appliance, or a hollow container such as such a can.

Among them, from the viewpoint of suppressing mold contamination during molding, and also from the viewpoint of excellent thin-wall fluidity and dimensional stability, the present invention is particularly useful for electric/electronic components such as box-shaped and cylindrical connectors, relays, switches, bobbins, lamp sockets, camera modules, and integrated circuit sealing materials, which have metal terminal portions and are thin-walled.

Examples

The present invention will be described below with reference to examples, but the present invention is not limited to the examples. In the examples, the composition and the characteristic evaluation of the liquid crystal polyester resin were measured by the following methods.

(1) Composition analysis of liquid-crystalline polyester resin

To 0.1mg of the pulverized liquid-crystalline polyester resin particles, 2. mu.L of a 25% methanol solution of tetramethylammonium hydroxide was added, and the composition ratio of each component in the liquid-crystalline polyester resin was determined by thermal decomposition GC/MS measurement using GCMS-QP5050A, manufactured by Shimadzu corporation.

(2) Melting Point (Tm) of liquid Crystal polyester resin

Using a differential scanning calorimeter DSC-7 (manufactured by パーキンエルマー), an endothermic peak temperature (Tm) observed when a liquid crystal polyester resin is heated from room temperature under a temperature raising condition of 20 ℃/min was observed₁) After, at Tm₁Holding at +20 deg.C for 5 min, cooling to room temperature at 20 deg.C/min, heating at 20 deg.C/min, and adjusting the endothermic peak temperature (Tm) observed at the time₂) The melting point is defined. In the following production examples, the melting point (Tm) is shown₂) Is described as Tm.

(3) Melt viscosity of liquid-crystalline polyester resin

The melt viscosity of the liquid crystal polyester resin was measured using a Koshikazu Kogyo-Kagaku Kogyo CFT-500D (orifice diameter: 0.5. phi. times.10 mm) (Shimadzu corporation) under the conditions of Tm +20 ℃ and shear rate 1000/s.

(4) Thin wall fluidity

After the pellets obtained in each of examples and comparative examples were hot-air dried at 150 ℃ for 3 hours using a hot-air dryer, they were fed to a ファナック α 30C injection molding machine manufactured by ファナック (ltd.) so that the resin temperature was +20 ℃ which is the melting point of the liquid crystal polyester, the mold temperature was 90 ℃, the injection pressure was 100MPa, and the speed was set to the lowest filling speed, and a connector molded article having a terminal pitch of 0.4mm, a minimum wall thickness portion (spacer 3) of 0.2mm, and an outer dimension of 3mm in width by 2mm in height by 30mm in length as shown in fig. 1a was obtained. Fig. 1a is a perspective view of the connector molded product. A liquid crystal polyester resin or a resin composition was filled from a pin gate G1 (gate diameter 0.3mm) provided on the short strip face 2 on one side of the connector molded article. The number of unfilled occurrences was evaluated with respect to the filling property of the wall corner on the gate opposite surface side by performing 500 injection molding. The corner portions are portions where unfilled portions are likely to occur due to variations in the amount of filling, and the thinner the number of unfilled portions, the better the thin-wall fluidity.

(5) Contamination of mold

0.05 part by weight of a release agent (manufactured by LicowaxE, クラリアント) was added to 100 parts by weight of pellets obtained in each of examples and comparative examples, and after hot-air drying was carried out at 150 ℃ for 3 hours using a hot-air dryer, the pellets were fed to a ファナック α 30C injection molding machine manufactured by ファナック (Co., Ltd.) so that the resin temperature was +20 ℃ which is the melting point of the liquid crystal polyester and the mold temperature was 90 ℃, and a square plate-shaped molded article having a thickness of 50mm × 50mm × 1mm was continuously molded in a molding cycle of 12 seconds. The adhesion of mold deposit was visually confirmed every 100 injections, and the mold deposit was continuously formed by a maximum of 1000 injections until the adhesion of mold deposit was confirmed. The number of injections at the time when adhesion in the mold cavity was confirmed was regarded as mold fouling. It was confirmed that the larger the number of shots of mold deposit adhering to the inside of the mold cavity, the less mold contamination and the more excellent the mold contamination. When the adhesion of mold deposit was not confirmed even after 1000 times of injection continuous molding, "> 1000" was set.

(6) Dimensional stability

The molding was performed under the same conditions as in (4), and the amount of warpage after the heat treatment of the connector molded article was measured with respect to the completely filled molded article. The heat treatment was performed by leaving the connector molded article in an oven heated to 260 ℃ for 3 minutes. The warpage amount was measured as a dimensional difference from a horizontal flat plate using a universal projector (V-16A (manufactured by Nikon)) with both ends of a long molded article in the longitudinal direction thereof being connected by a straight line as a reference in a state where the molded article was left standing still on the horizontal flat plate in the longitudinal direction. FIG. 1B is a conceptual diagram showing a measurement site of the amount of warpage in the long molded article, and the amount of warpage is defined as the difference from the maximum deformation plane B with the reference plane a-B. The smaller the amount of warpage, the more excellent the dimensional stability.

[ example 1]

A5L reaction vessel equipped with a stirring blade and a distillation tube was charged with 932 parts by weight of p-hydroxybenzoic acid, 283 parts by weight of 4, 4' -dihydroxybiphenyl, 99 parts by weight of hydroquinone, 284 parts by weight of terephthalic acid, 90 parts by weight of isophthalic acid, 3 parts by weight of 1, 4-cyclohexanedimethanol, and 1242 parts by weight of acetic anhydride (1.05 equivalents in total of phenolic hydroxyl groups), reacted at 145 ℃ for 1 hour while stirring in a nitrogen atmosphere, and then the jacket temperature of the reaction vessel was increased from 145 ℃ to 350 ℃ over 4 hours. Then, the polymerization temperature was maintained at 350 ℃ and the pressure was reduced to 1.0mmHg (133Pa) for 1.0 hour, and then the reaction was continued, and the polymerization was completed when the torque required for stirring reached 8kg · cm. Next, the inside of the reaction vessel was pressurized to 1.0kg/cm²(0.1MPa), the polymer was discharged as a strand through a die having 1 circular discharge port with a diameter of 10mm, and pelletized by a cutter to obtain a liquid crystal polyester resin (A-1). The obtained liquid-crystalline polyester resin had a Tm of 327 ℃ and a melt viscosity of 9 pas.

[ example 2]

870 parts by weight of p-hydroxybenzoic acid, 338 parts by weight of 4, 4' -dihydroxybiphenyl, 119 parts by weight of hydroquinone, 247 parts by weight of terephthalic acid, 202 parts by weight of isophthalic acid, 3 parts by weight of 1, 4-cyclohexanedimethanol, and 1321 parts by weight of acetic anhydride (1.07 equivalents in total of phenolic hydroxyl groups) were charged into a 5L reaction vessel equipped with a stirring blade and a distillation tube, and reacted at 145 ℃ for 1 hour while stirring in a nitrogen atmosphere, and then the jacket temperature of the reaction vessel was increased from 145 ℃ to 330 ℃ over 4 hours. Then, willThe polymerization temperature was maintained at 330 ℃ and the pressure was reduced to 1.0mmHg (133Pa) over 1.0 hour, and then the reaction was continued, and the polymerization was completed when the torque required for stirring reached 10kg · cm. Next, the inside of the reaction vessel was pressurized to 1.0kg/cm²(0.1MPa), the polymer was discharged as a strand through a die having 1 circular discharge port with a diameter of 10mm, and pelletized by a cutter to obtain a liquid crystal polyester resin (A-2). The obtained liquid-crystalline polyester resin had a Tm of 308 ℃ and a melt viscosity of 9 pas.

Comparative example 1

A5L reaction vessel equipped with a stirring blade and a distillation tube was charged with 932 parts by weight of p-hydroxybenzoic acid, 283 parts by weight of 4, 4' -dihydroxybiphenyl, 99 parts by weight of hydroquinone, 284 parts by weight of terephthalic acid, 90 parts by weight of isophthalic acid and 1242 parts by weight of acetic anhydride (1.05 equivalents in total of phenolic hydroxyl groups), reacted at 145 ℃ for 1 hour while stirring under a nitrogen atmosphere, and then the jacket temperature of the reaction vessel was increased from 145 ℃ to 350 ℃ over 4 hours. Then, the polymerization temperature was maintained at 350 ℃ and the pressure was reduced to 1.0mmHg (133Pa) for 1.0 hour, and then the reaction was continued, and the polymerization was completed when the torque required for stirring reached 8kg · cm. Next, the inside of the reaction vessel was pressurized to 1.0kg/cm²(0.1MPa), the polymer was discharged as a strand through a die having 1 circular discharge port with a diameter of 10mm, and pelletized by a cutter to obtain a liquid crystalline polyester resin (A-3). The obtained liquid-crystalline polyester resin had a Tm of 328 ℃ and a melt viscosity of 9 pas.

Comparative example 2

870 parts by weight of p-hydroxybenzoic acid, 338 parts by weight of 4, 4' -dihydroxybiphenyl, 119 parts by weight of hydroquinone, 247 parts by weight of terephthalic acid, 202 parts by weight of isophthalic acid and 1302 parts by weight of acetic anhydride (1.07 equivalents in total of phenolic hydroxyl groups) were charged into a 5L reaction vessel equipped with a stirring blade and a distillation tube, and reacted at 145 ℃ for 1 hour while stirring under a nitrogen atmosphere, and then the jacket temperature of the reaction vessel was increased from 145 ℃ to 330 ℃ over 4 hours. Then, the polymerization temperature was maintained at 330 ℃ and the pressure was reduced to 1.0mmHg (133Pa) for 1.0 hour, and the reaction was continued, and the torque required for stirring was 10 kg. multidot.cmAnd (4) finishing. Next, the inside of the reaction vessel was pressurized to 1.0kg/cm²(0.1MPa), the polymer was discharged as a strand through a die having 1 circular discharge port with a diameter of 10mm, and pelletized by a cutter to obtain a liquid crystalline polyester resin (A-4). The obtained liquid-crystalline polyester resin had a Tm of 310 ℃ and a melt viscosity of 9 pas.

Comparative example 3

994 parts by weight of p-hydroxybenzoic acid, 126 parts by weight of 4, 4' -dihydroxybiphenyl, 112 parts by weight of terephthalic acid, 216 parts by weight of polyethylene terephthalate having an intrinsic viscosity of about 0.6dl/g, and 960 parts by weight of acetic anhydride (1.10 equivalents in total of phenolic hydroxyl groups) were charged into a 5L reaction vessel equipped with a stirring blade and a distillation tube, reacted at 145 ℃ for 1 hour while stirring in a nitrogen atmosphere, and then heated from 145 ℃ to 320 ℃ over 4 hours. Then, the polymerization temperature was maintained at 320 ℃ and the pressure was reduced to 1.0mmHg (133Pa) over 1.0 hour, and then the reaction was continued, and the polymerization was completed when the torque required for stirring reached 15kg · cm. Next, the inside of the reaction vessel was pressurized to 1.0kg/cm²(0.1MPa), the polymer was discharged as a strand through a die having 1 circular discharge port with a diameter of 10mm, and pelletized by a cutter to obtain a liquid crystalline polyester resin (A-5). The obtained liquid-crystalline polyester resin had a Tm of 312 ℃ and a melt viscosity of 9 pas.

Comparative example 4

808 parts by weight of p-hydroxybenzoic acid, 503 parts by weight of 4, 4' -dihydroxybiphenyl, 374 parts by weight of terephthalic acid, 75 parts by weight of isophthalic acid, 85 parts by weight of 6-hydroxy-2-naphthoic acid and 1254 parts by weight of acetic anhydride (1.05 equivalents of the total of phenolic hydroxyl groups) were charged into a 5L reaction vessel equipped with a stirring blade and a distillation tube, and reacted at 145 ℃ for 1 hour while stirring in a nitrogen atmosphere, and then the jacket temperature of the reaction vessel was raised from 145 ℃ to 360 ℃ over 4 hours. Then, the polymerization temperature was maintained at 360 ℃ and the pressure was reduced to 1.0mmHg (133Pa) for 1.0 hour, and then the reaction was continued, and the polymerization was completed when the torque required for stirring reached 10kg · cm. Next, the inside of the reaction vessel was pressurized to 1.0kg/cm²(0.1MPa), polymer was discharged through a die having 1 circular discharge port with a diameter of 10mmThe resultant was pelletized by a cutter to obtain a liquid-crystalline polyester resin (A-6). The obtained liquid-crystalline polyester resin had a Tm of 350 ℃ and a melt viscosity of 9 pas.

Comparative example 5

To a 5L reaction vessel equipped with a stirring blade and a distillation tube, 497 parts by weight of p-hydroxybenzoic acid, 285 parts by weight of 4, 4' -dihydroxybiphenyl, 228 parts by weight of hydroquinone, 598 parts by weight of terephthalic acid, 85 parts by weight of 6-hydroxy-2-naphthoic acid and 1206 parts by weight of acetic anhydride (1.05 equivalent of the total phenolic hydroxyl groups) were charged, and the reaction was carried out at 145 ℃ for 1 hour under stirring in a nitrogen atmosphere, and then the jacket temperature of the reaction vessel was increased from 145 ℃ to 350 ℃ over 4 hours. Then, the polymerization temperature was maintained at 350 ℃ and the pressure was reduced to 1.0mmHg (133Pa) for 1.0 hour, and then the reaction was continued, and the polymerization was completed when the torque required for stirring reached 10kg · cm. Next, the inside of the reaction vessel was pressurized to 1.0kg/cm²(0.1MPa), the polymer was discharged as a strand through a die having 1 circular discharge port with a diameter of 10mm, and pelletized by a cutter to obtain a liquid crystalline polyester resin (A-7). The obtained liquid-crystalline polyester resin had a Tm of 333 ℃ and a melt viscosity of 9 pas.

Comparative example 6

A5L reaction vessel equipped with a stirring blade and a distillation tube was charged with 932 parts by weight of p-hydroxybenzoic acid, 419 parts by weight of 4, 4' -dihydroxybiphenyl, 254 parts by weight of terephthalic acid, 120 parts by weight of isophthalic acid and 1206 parts by weight of acetic anhydride (1.05 equivalents of the total phenolic hydroxyl groups), reacted at 145 ℃ for 1 hour while stirring under a nitrogen atmosphere, and then the jacket temperature of the reaction vessel was increased from 145 ℃ to 340 ℃ over 4 hours. Then, the polymerization temperature was maintained at 340 ℃ and the pressure was reduced to 1.0mmHg (133Pa) over 1.0 hour, and then the reaction was continued, and the polymerization was completed when the torque required for stirring reached 10kg · cm. Next, the inside of the reaction vessel was pressurized to 1.0kg/cm²(0.1MPa), the polymer was discharged as a strand through a die having 1 circular discharge port with a diameter of 10mm, and pelletized by a cutter to obtain a liquid crystalline polyester resin (A-8). The obtained liquid-crystalline polyester resin had a Tm of 328 ℃ and a melt viscosity of 9 pas.

Comparative example 7

31 parts by weight of p-hydroxybenzoic acid, 524 parts by weight of 4, 4' -dihydroxybiphenyl, 467 parts by weight of terephthalic acid, 1016 parts by weight of 6-hydroxy-2-naphthoic acid and 1206 parts by weight of acetic anhydride (1.05 equivalent of the total of phenolic hydroxyl groups) were charged into a 5L reaction vessel equipped with a stirring blade and a distillation tube, and reacted at 145 ℃ for 1 hour while stirring under a nitrogen atmosphere, and then the jacket temperature of the reaction vessel was increased from 145 ℃ to 360 ℃ over 4 hours. Then, the polymerization temperature was maintained at 360 ℃ and the pressure was reduced to 1.0mmHg (133Pa) over 1.0 hour, and the reaction was continued, and the polymerization was completed when the torque required for stirring reached 10kg · cm. Next, the inside of the reaction vessel was pressurized to 1.0kg/cm²(0.1MPa), the polymer was discharged as a strand through a die having 1 circular discharge port with a diameter of 10mm, and pelletized by a cutter to obtain a liquid crystalline polyester resin (A-9). The obtained liquid-crystalline polyester resin had a Tm of 350 ℃ and a melt viscosity of 9 pas.

Comparative example 8

994 parts by weight of p-hydroxybenzoic acid, 126 parts by weight of 4, 4' -dihydroxybiphenyl, 112 parts by weight of terephthalic acid, 216 parts by weight of polyethylene terephthalate having an intrinsic viscosity of about 0.6dl/g, 3 parts by weight of 1, 4-cyclohexanedimethanol, and 963 parts by weight of acetic anhydride (1.10 equivalents in total of phenolic hydroxyl groups) were charged into a 5L reaction vessel equipped with a stirring blade and a distillation tube, reacted at 145 ℃ for 1 hour while stirring in a nitrogen atmosphere, and then heated from 145 ℃ to 320 ℃ over 4 hours. Then, the polymerization temperature was maintained at 320 ℃ and the pressure was reduced to 1.0mmHg (133Pa) over 1.0 hour, and then the reaction was continued, and the polymerization was completed when the torque required for stirring reached 15kg · cm. Next, the inside of the reaction vessel was pressurized to 1.0kg/cm²(0.1MPa), the polymer was discharged as a strand through a die having 1 circular discharge port with a diameter of 10mm, and pelletized by a cutter to obtain a liquid crystal polyester resin (A-10). The obtained liquid-crystalline polyester resin had a Tm of 311 ℃ and a melt viscosity of 9 pas.

The results of composition analysis by the method described in (1) above and the results of evaluation of (4) to (6) are shown in table 1 for the particles obtained in examples 1 and 2 and comparative examples 1 to 8.

[ Table 1]

Then, the additives (a-1) to (a' -5) were further melt-kneaded with the liquid crystal polyester resins (A-3) to (A-9) obtained as described above to prepare liquid crystal polyester resins.

The compounds used in the respective examples and comparative examples are shown next.

(a-1): 1, 4-cyclohexanediol (molecular weight: 116) manufactured by Tokyo chemical industry Co., Ltd

(a-2): 1, 4-cyclohexanedimethanol (molecular weight: 144) manufactured by Tokyo chemical industry Co., Ltd

(a-3): cyclohexane-1, 4-diylbis (methylene) bis (4-hydroxybenzoate) (molecular weight: 384) (compound obtained by ester-bonding 2 hydroxyl groups of 1, 4-cyclohexanedimethanol and carboxyl group of p-hydroxybenzoic acid) synthesized in production example 1 below

(a' -4): 4, 4' -dihydroxybiphenyl (molecular weight: 186) manufactured by Tokyo chemical industry Co., Ltd

(a' -5): 1, 4-Cyclohexanedicarboxylic acid (molecular weight: 172) manufactured by Tokyo chemical industry Co., Ltd.

Next, an example of production of (a-3) will be shown.

Production example 1

75 parts by weight of p-hydroxybenzoic acid, 43 parts by weight of 1, 4-cyclohexanedimethanol, and 4 drops of concentrated sulfuric acid were added to toluene, and only toluene was refluxed and heated for 3 hours while water generated by the reaction was removed by azeotropic distillation to the outside of the system. After cooling to room temperature, methanol was added and the resulting solution was filtered. Further washed with methanol several times, and dried to give (a-3).

Examples 3 to 12 and comparative examples 9 to 12

A TEM35B type twin screw extruder, a toshiba machine equipped with a side inlet, was used, and the side inlet was provided in the C3 part of the cylinder C1 (main inlet side heater) to C6 (die side heater), and the vacuum vent was provided in the C5 part. A screw arrangement in which kneading blocks were grouped into sections C2 and C4 was used. Liquid crystal polyester resins (A-3) to (A-9) and additives (a-1) to (a' -5) were fed from a main feed port at the blending amounts shown in Table 2, and melt-kneaded at a cylinder temperature of +10 ℃ which is the melting point of the liquid crystal polyester resin and a screw rotation speed of 200rpm to obtain pellets. The obtained pellets of the liquid crystal polyester resin were hot-air dried at 150 ℃ for 3 hours using a hot-air dryer, and then evaluated in the above-mentioned items (1) and (4) to (6). The results are shown in Table 2.

[ Table 2]

Then, the liquid crystal polyester resins (A-1) to (A-10) obtained as described above were mixed with an inorganic filler to prepare liquid crystal polyester resins. Next, the inorganic fillers (b-1) to (b-3) used in the examples and comparative examples are shown.

(b-1): ヤマグチマイカ mica "NJ-030"

(b-2): talc "RL 217" manufactured by Fuji タルク, Inc. "

(b-3): EPG (70MD-01N)/P9W (manufactured by Nippon Kabushiki Kaisha Co., Ltd.).

Examples 13 and 14 and comparative examples 13 to 20

Pellets were obtained by melt-kneading in the same manner as in examples 3 to 12 and comparative examples 9 to 12, except that the liquid crystal polyester resins (A-1) to (A-10) were charged from the main feed port at the blending amount shown in Table 3, and the inorganic fillers (b-1) to (b-3) were charged from the side feed port at the blending amount shown in Table 3, and the above-mentioned evaluations (4) to (6) were carried out. The results are shown in Table 3.

[ Table 3]

TABLE 3

Examples 15 to 25 and comparative examples 21 to 24

Pellets were obtained by melt-kneading in the same manner as in examples 3 to 12 and comparative examples 9 to 12 except that the inorganic fillers (b-1) to (b-3) were charged from the side inlet at the blending amounts shown in Table 4, and the above-mentioned evaluations (1) and (4) to (6) were performed. The results are shown in Table 4.

[ Table 4]

From the results in tables 1 to 4, it is understood that the liquid crystal polyester resin and the liquid crystal polyester resin composition of the present invention are excellent in thin-wall flowability and dimensional stability while suppressing mold contamination. Therefore, it can be said that the resin composition is suitable for use in electric/electronic components and mechanical components such as thin-walled box-shaped or cylindrical connectors, relays, switches, bobbins, lamp sockets, camera modules, and integrated circuit sealing materials.

Industrial applicability

The liquid crystal polyester resin and the liquid crystal polyester resin composition of the present invention are suitable for electric/electronic parts and mechanical parts having a thin box-like or cylindrical shape, such as connectors, relays, switches, bobbins, lamp sockets, camera modules, and integrated circuit sealing materials, because they are excellent in thin-wall fluidity and dimensional stability while suppressing mold contamination.

Description of the symbols

1 strip surface

2 short noodles

3 Length (30mm)

4 height (2mm)

5 Width (3mm)

6 space distance (0.4mm)

7 minimum thickness part (0.2mm)

8 amount of warp

G1 pin point gate

a reference plane

b maximum deformation surface.

Claims

1. A liquid crystal polyester resin comprising 15 to 80 mol% of a structural unit derived from an aromatic hydroxycarboxylic acid, 7 to 40 mol% of a structural unit derived from an aromatic diol, 7 to 40 mol% of a structural unit derived from an aromatic dicarboxylic acid, and 0.01 to 5 mol% of at least 1 structural unit selected from the following structural units (I) and (II) relative to 100 mol% of the total structural units of the liquid crystal polyester resin,

2. the liquid-crystalline polyester resin according to claim 1, wherein the structural unit derived from an aromatic hydroxycarboxylic acid comprises the following structural unit (III), the structural unit derived from an aromatic dicarboxylic acid comprises the following structural unit (IV), and the total of the structural unit (III) and the structural unit (IV) is 60 to 80 mol% based on 100 mol% of the total structural units of the liquid-crystalline polyester resin,

3. the liquid-crystalline polyester resin according to claim 1 or 2, wherein the structural unit derived from an aromatic diol is 2 to 20 mol% relative to 100 mol% of the total structural units of the liquid-crystalline polyester resin,

4. the liquid-crystalline polyester resin according to any one of claims 1 to 3, wherein at least 1 structural unit selected from the structural units (I) and (II) comprises the structural unit (II) as an essential component.

5. The liquid-crystalline polyester resin according to any one of claims 1 to 4, which is obtained by compounding a liquid-crystalline polyester resin not containing a structural unit selected from the structural unit (I) and the structural unit (II), and a compound having at least 1 structure selected from the structural unit (I) and the structural unit (II).

6. The method for producing a liquid-crystalline polyester resin according to any one of claims 1 to 4, wherein a liquid-crystalline polyester resin not containing a structural unit selected from the structural unit (I) and the structural unit (II), and a compound having at least 1 structure selected from the structural unit (I) and the structural unit (II) are melt-kneaded.

7. A liquid crystal polyester resin composition comprising 10 to 200 parts by weight of a filler per 100 parts by weight of the liquid crystal polyester resin according to any one of claims 1 to 5.

8. A molded article comprising the liquid-crystalline polyester resin according to any one of claims 1 to 5 or the liquid-crystalline polyester resin composition according to claim 7.

9. The molded article of claim 8, wherein the molded article is selected from the group consisting of a connector, a relay, a switch, a coil bobbin, a lamp holder, a camera module, and an integrated circuit sealing material.