WO2019198665A1

WO2019198665A1 - Liquid crystal polyester resin, method for manufacturing same, and molded article comprising same

Info

Publication number: WO2019198665A1
Application number: PCT/JP2019/015328
Authority: WO
Inventors: 小西彬人; 宮本皓平; 梅津秀之
Original assignee: 東レ株式会社
Priority date: 2018-04-13
Filing date: 2019-04-08
Publication date: 2019-10-17
Also published as: KR20200141991A; JP6652223B1; KR102644138B1; TW201943761A; CN111936547A; JPWO2019198665A1; TWI797308B; CN111936547B

Abstract

This liquid crystal polyester resin includes, with respect to 100 mol% of the total structural units of a liquid crystal polyester resin, the following: 15-80 mol% of structural units derived from an aromatic hydroxycarboxylic acid; 7-40 mol% of structural units derived from aromatic diol; 7-40 mol% of structural units derived from aromatic dicarboxylic acid; and 0.01-5 mol% of at least one kind of structural unit selected from structural units (I) and (II). Provided are: the liquid crystal polyester resin that has excellent thin section fluidity and dimensional stability, and suppresses mold soiling; and a molded article comprising the same.

Description

Liquid crystalline polyester resin, method for producing the same, and molded product comprising the same

The present invention relates to a liquid crystal polyester resin and a molded product comprising the same. More specifically, the present invention relates to a liquid crystal polyester resin capable of obtaining a molded product having excellent fluidity and dimensional stability while suppressing mold contamination during molding, and a molded product comprising the same.

Since liquid crystal polyester resin has a liquid crystal structure, it has excellent heat resistance, fluidity and dimensional stability. For this reason, the demand is expanding mainly for the use of electrical and electronic parts such as connectors and relays that require these characteristics. In particular, with the recent improvement in performance of equipment, the above-mentioned parts have been reduced in size and thickness, and further fluidity is required. Therefore, for example, improvement in fluidity has been proposed by melting and kneading a low molecular weight compound in a liquid crystal polymer to obtain a liquid crystal polymer having a low melt viscosity (see, for example, Patent Documents 1 and 2). Further, as a method for changing the chemical species of the molecular skeleton of a liquid crystal polyester resin, improvement in fluidity by using a liquid crystal polyester amide containing a structure derived from acetaminophenone or 1,4-cyclohexanedicarboxylic acid has been proposed (for example, Patent Documents). 3).

Japanese translation of PCT publication No. 2002-511513 JP-A-2018-44108 International Publication No. 2013/115168

On the other hand, when the melt viscosity of the liquid crystal polyester resin is reduced by the method described in

Patent Documents

1 and 2, the high processing required for molding the liquid crystal polyester resin is low because the heat resistance of the low molecular weight compound itself is low. In terms of temperature, there is a problem in that gas decomposes and gas increases, the mold becomes dirty at the time of molding, and dimensional stability decreases. Further, the thin wall fluidity was also insufficient. Further, the liquid crystal polyester amide resin described in Patent Document 3 also has problems in mold contamination and dimensional stability, and the thin-wall fluidity is insufficient.

The present invention solves the above-mentioned problems, and provides a liquid crystal polyester resin capable of obtaining a molded product excellent in fluidity and dimensional stability while suppressing mold contamination during molding, and a molded product thereof. Is an issue.

As a result of intensive studies to solve the above-mentioned problems, the inventors of the present invention have achieved liquidity and dimensional stability while suppressing mold contamination during molding with a liquid crystal polyester resin containing a small amount of a specific structural unit. The present inventors have found that an excellent molded product can be obtained.

The present invention is:
(1) 15 to 80 mol% of structural units derived from aromatic hydroxycarboxylic acid, 7 to 40 mol% of structural units derived from aromatic diol, and 100% by mol of all structural units of liquid crystal polyester resin Liquid crystal polyester resin containing 7 to 40% of structural units derived from a group dicarboxylic acid and 0.01 to 5 mol% of at least one structural unit selected from the following structural units (I) and (II).

(2) The liquid crystalline polyester resin includes the structural unit (III) as a structural unit derived from an aromatic hydroxycarboxylic acid, and includes the following structural unit (IV) as a structural unit derived from an aromatic dicarboxylic acid. The liquid crystal polyester resin according to (1), wherein the total of (III) and the structural unit (IV) is 60 to 80 mol% with respect to 100 mol% of all structural units of the liquid crystal polyester resin.

(3) The liquid crystalline polyester resin contains the following structural unit (V) as a structural unit derived from an aromatic diol, and the structural unit (V) is 2 to 20 with respect to 100 mol% of all structural units of the liquid crystalline polyester resin. % Liquid crystal polyester resin according to (1) or (2).

(4) The liquid crystalline polyester according to any one of (1) to (3), wherein at least one structural unit selected from the structural units (I) and (II) includes the structural unit (II) as an essential component. resin.
(5) A liquid crystal polyester resin not containing a structural unit selected from the structural units (I) and (II) and a compound having at least one structure selected from the structural units (I) and (II) are blended. The liquid crystal polyester resin according to any one of (1) to (4).
(6) Melt-knead a liquid crystal polyester not containing a structural unit selected from the structural units (I) and (II) and a compound having at least one structure selected from the structural units (I) and (II). (1) The method for producing a liquid crystal polyester resin according to any one of (5).
(7) A liquid crystal polyester resin composition comprising 10 to 200 parts by weight of a filler with respect to 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 crystalline polyester resin according to any one of (1) to (5) or the liquid crystalline polyester resin composition according to (7).
(9) The molded product according to (8), wherein the molded product is selected from the group consisting of a connector, a relay, a switch, a coil bobbin, a lamp socket, a camera module, and an integrated circuit sealing material.

According to the liquid crystal polyester resin of the present invention, it is possible to obtain a molded product excellent in fluidity and dimensional stability while suppressing mold contamination during molding. Such a resin is particularly suitable for electrical / electronic parts and mechanical parts such as connectors, relays, switches, coil bobbins, lamp sockets, camera modules, integrated circuit sealing materials having a thin box shape or cylindrical shape.

It is a conceptual diagram which shows the perspective view of the connector molded article produced in the Example, and the measurement site | part of the curvature amount.

Hereinafter, the present invention will be described in detail.

<Liquid crystal polyester resin>
The liquid crystal polyester resin used in the present invention is a polyester that forms an anisotropic molten phase. Examples of the liquid crystal polyester resin include polyesters composed of structural units selected to form an anisotropic molten phase from oxycarbonyl units, dioxy units, dicarbonyl units and the like described later.

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

The liquid crystal polyester resin of the present invention contains 15 to 80 mol% of oxycarbonyl units, that is, structural units derived from aromatic hydroxycarboxylic acid, with respect to 100 mol% of all structural units of the liquid crystal polyester resin. If the content of the oxycarbonyl unit is less than 15 mol%, the liquid crystallinity is impaired, so that the fluidity of the liquid crystal polyester resin is lowered and the dimensional stability is also lowered. From the viewpoint of improving fluidity and dimensional stability, the content of oxycarbonyl units is preferably 20 mol% or more, and more preferably 25 mol% or more. On the other hand, when the content of the oxycarbonyl unit is more than 80 mol%, it becomes difficult to control the crystallinity and melting point of the liquid crystal polyester resin, and the fluidity and dimensional stability are lowered. From the viewpoint of improving fluidity and dimensional stability, the content of oxycarbonyl units is preferably 75 mol% or less, and more preferably 70 mol% or less.

As specific examples of the oxycarbonyl unit, structural units derived from p-hydroxybenzoic acid, m-hydroxybenzoic acid, 6-hydroxy-2-naphthoic acid and the like can be used.

The liquid crystalline polyester resin of the present invention contains 7 to 40 mol% of dioxy units, that is, structural units derived from aromatic diol, with respect to 100 mol% of all structural units of the liquid crystalline polyester resin. When the content of dioxy units is less than 5 mol%, it becomes difficult to control the crystallinity and melting point of the liquid crystal polyester resin, and the fluidity and dimensional stability are lowered. From the viewpoint of improving fluidity and dimensional stability, the content of dioxy units is preferably 10 mol% or more, and more preferably 15 mol% or more. On the other hand, when the content of the dioxy unit is more than 40 mol%, the liquid crystallinity is impaired, so that the fluidity of the liquid crystal polyester resin is lowered and the dimensional stability is also lowered. From the viewpoint of improving fluidity and dimensional stability, the content of dioxy units is preferably 37 mol% or less, and more preferably 35 mol% or less.

In addition to the structural unit derived from the aromatic diol having the above content, the liquid crystalline polyester resin of the present invention has at least one structural unit selected from the following structural units (I) and (II) as a dioxy unit. And 0.01 to 5 mol% with respect to 100 mol% of all structural units of the liquid crystal polyester resin. The structural units (I) and (II) are structural units derived from 1,4-cyclohexanediol and 1,4-cyclohexanedimethanol, respectively. When the content of these structural units is less than 0.01 mol%, the thin-wall fluidity and dimensional stability are lowered. From the viewpoint of excellent thin-wall fluidity and dimensional stability, the content of these structural units is preferably 0.03 mol% or more, and more preferably 0.05 mol% or more. On the other hand, when the content of these structural units is more than 5 mol%, mold stains occur during molding, and thin-wall fluidity and dimensional stability are also reduced. The content of these structural units is preferably 3% or less and more preferably 1% or less from the viewpoint of excellent thin-wall fluidity and dimensional stability while suppressing mold contamination during molding. Further, the structural unit (I) and the structural unit (II) may have either one of the structural units, and the other structural unit may be 0 mol%, but it suppresses mold contamination during molding. However, it is preferable that the structural unit (II) is included as an essential component from the viewpoint of excellent thin-wall fluidity and dimensional stability.

Examples of structural units derived from aromatic diols include 4,4′-dihydroxybiphenyl, hydroquinone, resorcinol, t-butylhydroquinone, phenylhydroquinone, chlorohydroquinone, 2,6-dihydroxynaphthalene, 2,7-dihydroxynaphthalene, 3,4'-dihydroxybiphenyl, 2,2-bis (4-hydroxyphenyl) propane, 4,4'-dihydroxydiphenyl ether, 4,4'-dihydroxydiphenyl sulfone, 4,4'-dihydroxydiphenyl sulfide, 4,4 Examples include structural units derived from '-dihydroxybenzophenone and the like. It is preferable to use a structural unit selected from structural units derived from 4,4'-dihydroxybiphenyl and hydroquinone from the viewpoint of excellent fluidity and dimensional stability while suppressing mold contamination during molding. Further, it has structural units derived from aliphatic diols such as ethylene glycol, propylene glycol, 1,4-butanediol, 1,6-hexanediol, neopentyl glycol, etc., as long as liquid crystallinity and characteristics are not impaired. be able to.

The liquid crystal polyester resin of the present invention contains 7 to 40 mol% of structural units derived from aromatic dicarboxylic acid as dicarbonyl units with respect to 100 mol% of all structural units of the liquid crystal polyester resin. When 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 melting point of the liquid crystal polyester resin, and the fluidity and dimensional stability are lowered. From the viewpoint of improving fluidity and dimensional stability, 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. On the other hand, when there is more content of the structural unit derived from aromatic dicarboxylic acid than 40 mol%, since liquid crystallinity will be impaired, the fluidity | liquidity of liquid crystal polyester resin will fall and dimensional stability will also fall. From the viewpoint of improving fluidity and dimensional stability, the content of the structural unit derived from the aromatic dicarboxylic acid is preferably 37 mol% or less, and more preferably 35 mol% or less.

Examples of the structural unit derived from the aromatic dicarboxylic acid include terephthalic acid, isophthalic acid, 2,6-naphthalenedicarboxylic acid, 4,4′-diphenyldicarboxylic acid, 3,3′-diphenyldicarboxylic acid, and 2,2 ′. -Diphenyldicarboxylic acid, 1,2-bis (phenoxy) ethane-4,4'-dicarboxylic acid, 1,2-bis (2-chlorophenoxy) ethane-4,4'-dicarboxylic acid, 4,4'-diphenyl ether Examples include structural units derived from dicarboxylic acids and the like. It is preferable to use a structural unit selected from structural units derived from terephthalic acid and isophthalic acid from the viewpoint of excellent fluidity and dimensional stability while suppressing mold contamination during molding. In addition, structural units derived from aliphatic dicarboxylic acids such as adipic acid, azelaic acid, sebacic acid, dodecanedioic acid, hexahydroterephthalic acid, and alicyclic rings such as 1,4-cyclohexanedicarboxylic acid and 1,3-cyclohexanedicarboxylic acid A structural unit derived from the formula dicarboxylic acid can be further included in a range not impairing liquid crystallinity and characteristics.

Further, in addition to the above structural unit, a structural unit generated from p-aminobenzoic acid, p-aminophenol, or the like can be further included within a range that does not impair liquid crystallinity and characteristics.

The raw material monomer constituting each structural unit is not particularly limited as long as it is a structure capable of forming each structural unit. However, an acylated product of a hydroxyl group of each structural unit, an esterified product of a carboxyl group of each structural unit, an acid halogen, and the like. A carboxylic acid derivative such as a chemical compound or an acid anhydride may be used.

The liquid crystal polyester resin of the present invention includes the following structural unit (III) as a structural unit derived from an aromatic hydroxycarboxylic acid, and includes the following structural unit (IV) as a structural unit derived from an aromatic dicarboxylic acid. The total content of the unit (III) and the structural unit (IV) is preferably 60 to 80 mol% with respect to 100 mol% of all the structural units of the liquid crystal polyester resin. The total content of the structural unit (III) and the structural unit (IV) is preferably 63 mol% or more from the viewpoint of excellent thin-wall fluidity and dimensional stability, while controlling the crystallinity and melting point of the liquid crystal polyester resin. More preferably, it is 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 from the viewpoint of controlling the crystallinity and melting point of the liquid crystal polyester resin and being excellent in thin-wall fluidity and dimensional stability. % Or less. In addition, the structural unit (III) and the structural unit (IV) may have either one of the structural units, and the other structural unit may be 0 mol%. From the viewpoint of control, it is preferable to include both in excess of 0 mol%.

The content of the structural unit (III) is preferably 30 mol% or more and more preferably 50 mol% or more with respect to 100 mol% of all structural units of the liquid crystal polyester resin, from the viewpoint of excellent thin-wall fluidity and dimensional stability. . On the other hand, the content of the structural unit (III) is preferably 70 mol% or less, and 65 mol% or less from the viewpoint of excellent thin-wall fluidity and dimensional stability after controlling the crystallinity and melting point of the liquid crystal polyester resin. Is preferred.

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

The liquid crystalline polyester resin of the present invention contains the following structural unit (V) as a structural unit derived from an aromatic diol, and the structural unit (V) is 2 to 20 mol with respect to 100 mol% of the total structural units of the liquid crystalline polyester resin. % Content is preferable. The structural unit (V) is a structural unit derived from hydroquinone. By containing 2 mol% or more of the structural unit (V), the thin-wall fluidity and dimensional stability can be further improved. The content of the structural unit (V) is more preferably 4 mol% or more, and further 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 dimensional stability can be further improved. The content of the structural unit (V) is more preferably 15 mol% or less, and further preferably 12 mol% or less.

The liquid crystal polyester resin of the present invention contains the following structural unit (VI) as a structural unit derived from an aromatic diol, and the structural unit (VI) is 3 to 30 per 100 mol% of the total amount of structural units of the liquid crystal polyester resin. It is preferable to contain mol%. The structural unit (VI) is a structural unit derived from 4,4'-dihydroxybiphenyl. By containing 3 mol% or more of the structural unit (VI), the crystallinity and melting point of the liquid crystal polyester resin can be controlled, and the heat resistance is improved. Content of structural unit (VI) becomes like this. Preferably it is 5 mol% or more, More preferably, it is 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 is improved. The content of the structural unit (VI) is more preferably 25 mol% or less, and further preferably 20 mol% or less.

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

The content of each structural unit of the liquid crystal polyester resin in the present invention is determined by pulverizing the liquid crystal polyester pellets, adding tetramethylammonium hydroxide, and performing pyrolysis GC / MS measurement using a Shimadzu GCMS-QP5050A. be able to. The content of structural units not detected or below the detection limit is calculated as 0 mol%.

The melting point (Tm) of the liquid crystalline polyester resin of the present invention is preferably 220 ° C. or higher, more preferably 270 ° C. or higher, and further preferably 300 ° C. or higher from the viewpoint of heat resistance. On the other hand, the melting point (Tm) of the liquid crystal polyester resin is preferably 360 ° C. or lower, more preferably 355 ° C. or lower, from the viewpoint of suppressing deterioration of the liquid crystal polyester resin during processing and suppressing mold contamination during molding. More preferably, it is not more than ℃

The melting point (Tm) is measured by differential scanning calorimetry. Specifically, first, an endothermic peak temperature (Tm ₁ ) is observed by heating the polymer that has been polymerized from room temperature to a temperature rising condition of 20 ° C./min. After observation of an endothermic peak temperature (Tm _1), holding the polymer for 5 minutes at a temperature of the endothermic peak temperature _(Tm 1) + 20 ℃. Thereafter, the polymer is cooled to room temperature under a temperature drop condition of 20 ° C./min. Then, the endothermic peak temperature (Tm ₂ ) is observed by heating the polymer again under the temperature rising condition of 20 ° C./min. The melting point (Tm) refers to the endothermic peak temperature (Tm ₂ ) in the _second temperature raising process.

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

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

<Method for producing liquid crystal polyester resin>
Examples of the method for producing the liquid crystal polyester resin used in the present invention include the following methods.
(A) A method of adding a compound having at least one structure selected from the structural unit (I) and the structural unit (II) when producing according to a known polyester polycondensation method described later.
(B) A liquid crystal polyester resin not containing a structural unit selected from the structural units (I) and (II) is produced according to the known polyester polycondensation method described below, and then the structural unit (I) and the structural unit ( A method of blending a compound having at least one structure selected from II).

The moderate transesterification reaction with the liquid crystal polyester resin can further improve the thin-wall fluidity and dimensional stability while suppressing mold contamination during molding. Therefore, (B) the structural units (I) and (II) A method of blending a compound having at least one structure selected from the structural unit (I) and the structural unit (II) after producing a liquid crystal polyester resin not containing a structural unit selected from In addition, as a method of blending these, a method of melting and kneading them is preferable. A detailed manufacturing method will be described later.

Examples of the compound having at least one structure selected from the structural unit (I) and the structural unit (II) include 1,4-cyclohexanediol, 1,4-cyclohexanedimethanol, diol compounds such as oxycarbonyl units and dimers. Examples thereof include compounds in which one or more structural units that can constitute a liquid crystal polyester resin such as a carbonyl unit are ester-bonded. Among them, from the viewpoint of suppressing mold contamination during molding, 1,4-cyclohexanediol having two hydroxyl groups, 1,4-cyclohexanedimethanol, and an oxycarbonyl unit capable of constituting a liquid crystal polyester resin in the diol compound. Are compounds in which one or more of them are ester-bonded. Furthermore, since it has high heat resistance and suppresses thermal decomposition during polycondensation and melt-kneading, the liquid crystal polyester is added to the diol compound from the viewpoint of excellent thin-wall fluidity and dimensional stability while suppressing mold contamination during molding. A compound in which one or more oxycarbonyl units capable of constituting the resin are ester-bonded is more preferable, and a compound in which two or more ester bonds are bonded is particularly preferable. A compound in which an oxycarbonyl unit is further bonded next to the oxycarbonyl unit may be used, but the upper limit of the number of bonds of the oxycarbonyl unit does not generate an infusible substance derived from a long chain of rigid oxycarbonyl units. From the viewpoint, 10 or less is preferable, and 7 or less is more preferable.

Examples of the compound in which one or more oxycarbonyl units capable of constituting a liquid crystal polyester resin are ester-bonded to the diol compound include cyclohexane-1,4-diylbis (methylene) bis (4-hydroxybenzoate) and (4- (hydroxy And methyl) cyclohexyl) methyl 4-hydroxybenzoate, 4-hydroxycyclohexyl 4-hydroxybenzoate, and cyclohexane-1,4-diylbis (4-hydroxybenzoate).

These compounds are obtained by a method known to those skilled in the art, such as 1,4-cyclohexanediol or 1,4-cyclohexanedimethanol and an aromatic hydroxycarboxylic acid, for example, a method described in JP-T-2008-54495, It can manufacture by esterifying using. Specifically, 1,4-cyclohexanediol or 1,4-cyclohexanedimethanol and aromatic hydroxycarboxylic acid are reacted by heating under reflux in the presence of sulfuric acid in a solvent, and then purified by washing with methanol. By doing so, a compound in which one or more oxycarbonyl units capable of constituting a liquid crystal polyester resin are ester-bonded to the diol compound can be obtained.

The molecular weight of the compound having at least one structure selected from the structural unit (I) and the structural unit (II) is 200 from the viewpoint of excellent thin-wall fluidity and dimensional stability while suppressing mold contamination during molding. The above is preferable, 230 or more is more preferable, and 250 or more is more preferable. On the other hand, when the diol compound is a compound in which one or more structural units that can constitute the liquid crystal polyester resin are ester-bonded, the molecular weight is 1000 or less from the viewpoint of suppressing infusible product formation due to long chains of rigid structural units. Preferably, 700 or less is more preferable, and 500 or less is more preferable.

When the liquid crystal polyester resin is produced by the method (B), in order to bring the content of at least one selected from the structural unit (I) and the structural unit (II) into a desired range, the structural unit (I) and The compound having at least one structure selected from the structural unit (I) and the structural unit (II) is preferably 0.01 to 100 parts by weight of the liquid crystalline polyester resin not containing the structural unit selected from (II). It is preferable to blend by weight part or more, more preferably 0.03 part by weight or more, and still more preferably 0.05 part by weight or more. On the other hand, with respect to 100 parts by weight of the liquid crystal polyester resin not containing the structural unit selected from the structural units (I) and (II), at least one structure selected from the structural unit (I) and the structural unit (II) is used. It is preferable to blend the compound having 10 parts by weight or less, more preferably 7 parts by weight or less, and still more preferably 3 parts by weight or less.

Known polyester polycondensation methods include structural units derived from p-hydroxybenzoic acid, structural units derived from 4,4′-dihydroxybiphenyl, structural units derived from hydroquinone, structural units derived from terephthalic acid, and Taking the liquid crystal polyester resin comprising a structural unit derived from isophthalic acid as an example, the following may be mentioned.

(1) A method for producing a liquid crystal polyester resin from p-acetoxybenzoic acid, 4,4'-diacetoxybiphenyl, diacetoxybenzene, terephthalic acid and isophthalic acid by a deacetic acid condensation polymerization reaction.

(2) Liquid crystalline polyester by reacting p-hydroxybenzoic acid, 4,4'-dihydroxybiphenyl, hydroquinone, terephthalic acid, and isophthalic acid with acetic anhydride to acetylate the phenolic hydroxyl group, followed by deacetic acid polymerization A method for producing a resin.

(3) A method for producing a liquid crystal polyester resin from a phenyl p-hydroxybenzoate, 4,4'-dihydroxybiphenyl, hydroquinone, diphenyl terephthalate and diphenyl isophthalate by a dephenol polycondensation reaction.

(4) After reacting p-hydroxybenzoic acid, terephthalic acid and isophthalic acid with a predetermined amount of diphenyl carbonate to form phenyl esters, respectively, 4,4′-dihydroxybiphenyl and hydroquinone are added, and dephenol polycondensation reaction is performed. A method for producing a liquid crystal polyester resin.

Among them, (2) p-hydroxybenzoic acid, 4,4'-dihydroxybiphenyl, hydroquinone, terephthalic acid, and isophthalic acid are reacted with acetic anhydride to acetylate the phenolic hydroxyl group, and then deacetic acid polycondensation reaction. A method for producing a liquid crystal polyester resin is preferably used because it is industrially excellent in controlling the terminal structure of the liquid crystal polyester resin and controlling the degree of polymerization.

As a method for producing a liquid crystal polyester resin, the 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 a liquid crystal polyester resin is pulverized by a pulverizer. The pulverized polymer or oligomer is heated under a nitrogen stream or under reduced pressure, and polycondensed to a desired degree of polymerization to complete the reaction. The heating can be performed for 1 to 50 hours in the range of the melting point of the liquid crystal polyester to −50 ° C. to the melting point −5 ° C. (eg, 200 to 300 ° C.).

The polycondensation reaction of the liquid crystalline polyester resin proceeds even without catalyst, but stannous acetate, tetrabutyl titanate, potassium acetate and sodium acetate, antimony trioxide, magnesium metal, and the like can also be used as a catalyst.

<Liquid crystal polyester resin composition>
The liquid crystal polyester resin of the present invention can also be used as a resin composition containing a filler in order to impart mechanical strength and other characteristics of the liquid crystal polyester resin. Although it does not specifically limit as a filler, For example, a fibrous filler, a whisker-like filler, a plate-like filler, a powder filler, a granular filler, etc. can be mentioned. Specifically, as the fibrous filler and whisker-like filler, glass fiber; PAN-based or pitch-based carbon fiber; metal fiber such as stainless steel fiber, aluminum fiber or brass fiber; aromatic polyamide fiber or liquid crystal polyester fiber Organic fiber such as: gypsum fiber, ceramic fiber, asbestos fiber, zirconia fiber, alumina fiber, silica fiber, titanium oxide fiber, silicon carbide fiber, rock wool, potassium titanate whisker, barium titanate whisker, aluminum borate whisker, nitriding Examples thereof include silicon whiskers and acicular titanium oxide. Examples of the plate-like filler include mica, talc, kaolin, glass flake, clay, molybdenum disulfide, and wollastonite. Examples of the powder filler and the granular filler include silica, glass beads, titanium oxide, zinc oxide, calcium polyphosphate, and graphite. The surface of the filler may be treated with a known coupling agent (for example, a silane coupling agent or a titanate coupling agent) or other surface treatment agent. Two or more fillers may be used in combination.

Among the above fillers, glass fiber is particularly preferable from the viewpoints of excellent mechanical strength such as tensile strength and bending strength, heat resistance and dimensional stability. The type of glass fiber is not particularly limited as long as it is generally used for resin reinforcement, and examples thereof include long fiber type and short fiber type chopped strands, milled fibers, and the like. Moreover, it is preferable to use mica from the point which is excellent in thin-wall fluidity | liquidity.

The surface of the filler may be treated with a known coupling agent (for example, a silane coupling agent or a titanate coupling agent) or other surface treatment agent. The glass fiber 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 with respect to 100 parts by weight of the liquid crystalline polyester resin. A filler content of 10 parts by weight or more is preferable because the mechanical strength of the molded product can be improved. 15 parts by weight or more is more preferable, and 20 parts by weight or more is more preferable. On the other hand, when the filler content is 200 parts by weight or less, a liquid crystal polyester resin composition excellent in moldability and thin wall fluidity is obtained, which is preferable. 150 parts by weight or less is more preferable, and 100 parts by weight or less is more preferable.

In the liquid crystal polyester resin composition of the present invention, an antioxidant and a heat stabilizer (for example, hindered phenol, hydroquinone, phosphite, thioethers, and substituted products thereof, etc.) as long as the effects of the present invention are not impaired. UV absorbers (eg, resorcinol, salicylate), anti-coloring agents such as phosphites, hypophosphites, lubricants and mold release agents (montanic acid and its metal salts, its esters, their half esters, stearyl alcohol, Stearamide and polyethylene wax), colorants containing dyes or pigments, carbon black, crystal nucleating agents, plasticizers, flame retardants (bromine flame retardants, phosphorus flame retardants, red phosphorus, silicone flame retardants) Conventional additives selected from flame retardants, flame retardant aids, and antistatic agents. Can.

<Method for Producing Liquid Crystalline Polyester Resin Composition>
As a method for obtaining the liquid crystal polyester resin composition of the present invention, for example, a liquid crystal polyester resin that does not contain a structural unit selected from the structural units (I) and (II) can be obtained from the structural units (I) and (II). A dry blend method in which a compound having at least one selected structure, a filler, and other solid additives are blended, and a liquid crystal polyester resin not containing a structural unit selected from structural units (I) and (II) , A solution blending method, a structural unit (I) and a structural unit containing at least one compound selected from the structural unit (I) and the structural unit (II), a filler and other liquid additives A compound having at least one structure selected from (II), a filler and other additives are selected from structural units (I) and (II). A method of adding at the time of polymerization of a liquid crystal polyester resin not containing a structural unit, a liquid crystal polyester resin not containing a structural unit selected from the structural units (I) and (II), a structural unit (I) and a structural unit (II) A method of melt-kneading a compound having at least one structure, a filler, and other additives can be used. Of these, the melt kneading method is preferred. A known method can be used for melt kneading. For example, using a Banbury mixer, rubber roll machine, kneader, single-screw or twin-screw extruder, the above components can be melt-kneaded at a melting point of the liquid crystal polyester resin + 50 ° C. or lower to obtain a liquid crystal polyester resin composition. . Among these, melt kneading using a twin screw extruder is preferable.

For the twin screw extruder, in order to improve the dispersibility of the liquid crystalline polyester resin and the filler, it is preferable to provide one or more kneading parts, and more preferably to provide two or more kneading parts. When the liquid crystal polyester resin is produced by the method (B) described above, by providing the kneading part as described above, a liquid crystal polyester resin not containing a structural unit selected from the structural units (I) and (II); The dispersibility of the compound having at least one structure selected from the structural unit (I) and the structural unit (II) is improved, and both are appropriately transesterified to suppress mold contamination during molding. Moreover, thin-wall fluidity and dimensional stability can be further improved. For example, when the filler is added from the side feeder, the kneading portion is installed at one or more locations upstream of the side feeder of the filler in order to promote plasticization of the liquid crystalline polyester resin. In order to improve the dispersibility with the material, it is preferable to install two or more in total, one or more on the downstream side of the side feeder.

Further, it is preferable to provide a vent portion in order to remove moisture in the twin screw extruder and decomposition products generated during kneading. For example, when the filler is added from the side feeder, the vent portion is installed at one or more locations upstream of the side feeder into which the filler is charged in order to remove moisture adhering to the liquid crystalline polyester resin. In order to remove the carry-in air when supplying the cracked gas and filler, it is preferable to install two or more places, one or more places, downstream of the side feeder. The vent part may be under normal pressure or under reduced pressure.

The kneading method includes (1) a liquid crystal polyester resin that does not contain a structural unit selected from structural units (I) and (II), and at least one structure selected from structural units (I) and structural units (II). Compound (filler kneading method) in which compound, filler and other additives are added all at once from the original feeder and kneaded (2) Liquid crystalline polyester containing no structural unit selected from structural units (I) and (II) A resin, a compound having at least one structure selected from the structural unit (I) and the structural unit (II), and other additives are added from the original feeder and kneaded, and then the filler and other additives are side-loaded. Method of adding from a feeder and kneading (side feed method), (3) Liquid not containing a structural unit selected from structural units (I) and (II) A master pellet containing a polyester resin, a compound having at least one structure selected from the structural unit (I) and the structural unit (II), and other additives at a high concentration is prepared, and then a specified concentration is obtained. Examples thereof include a method (master pellet method) in which the master pellet is kneaded with the liquid crystalline polyester resin and the filler. Any method can be used.

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

Molded articles obtained by molding the liquid crystalline polyester resin or liquid crystalline polyester composition of the present invention include, for example, various gears, various cases, sensors, LED lamps, connectors, sockets, resistors, relay cases, relay bases, and relay spools. , Switch, coil bobbin, camera module, capacitor, variable capacitor case, optical pickup, oscillator, various terminal boards, transformer, plug, printed wiring board, tuner, speaker, microphone, headphones, small motor, magnetic head base, power module, Electrical and electronic parts represented by housings, semiconductors, integrated circuit sealing materials, liquid crystal display parts, FDD carriages, FDD chassis, HDD parts, motor brush holders, parabolic antennas, computer-related parts; V R parts, TV parts, irons, hair dryers, rice cooker parts, microwave oven parts, acoustic parts, audio equipment parts such as audio / laser discs / compact discs; lighting parts, refrigerator parts, air conditioner parts, personal computer parts, etc. Household, office electrical product parts; office computer-related parts, telephone-related parts, facsimile-related parts, copier-related parts, cleaning jigs, oilless bearings, stern bearings, submersible bearings, motor parts, etc. Machine-related parts: Optical instruments such as microscopes, binoculars, cameras, watches, precision machine-related parts: Alternator terminals, alternator connectors, IC regulators, light dimmer potentiometer bases, exhaust gas valves, and other fuel related ·exhaust・ Various intake pipes, air intake nozzle snorkel, intake manifold, fuel pump, engine coolant joint, carburetor main body, carburetor spacer, exhaust gas sensor, coolant sensor, oil temperature sensor, throttle position sensor, crankshaft position sensor, Air flow meter, brake butt wear sensor, thermostat base for air conditioner, motor insulator for air conditioner, automotive motor insulator such as power window, heating air flow control valve, brush holder for radiator motor, water pump impeller, turbine vane, wiper Motor parts, distributors, starter switches, starter relays, transmitters Wiring harness, window washer nozzle, air conditioner panel switch board, coil for fuel related solenoid valve, connector for fuse, horn terminal, electrical component insulation plate, step motor rotor, lamp bezel, lamp socket, lamp reflector, lamp housing, brake Automotive and vehicle-related parts such as pistons, solenoid bobbins, engine oil filters, ignition device cases; bottles for various chemicals such as shampoos, rinses, liquid soaps and detergents; chemical storage tanks, gas storage tanks, coolant tanks, oils Liquid transfer tanks, disinfectant tanks, transfusion pump tanks, fuel tanks, canisters, washer liquid tanks, oil reservoir tanks and other chemical and gas storage tanks; medical equipment parts; soy sauce, sauces, ketchup, ma Seasonings such as naise and dressing, fermented foods such as miso and vinegar, fats and oils such as salad oil, sake, beer, mirin, whiskey, shochu, wine and other alcoholic beverages, carbonated drinks, juices, sports drinks, milk, coffee drinks, It can be used for food storage containers such as soft drinks such as oolong tea, black tea, and mineral water; and tanks, bottle-shaped molded products, or hollow containers such as those tanks as parts for general living utensils.

Among them, connectors, relays, switches, and coil bobbins that have metal terminal parts and have a thin box shape or cylindrical shape because they are excellent in thin-wall fluidity and dimensional stability while suppressing mold contamination during molding. It is particularly useful for electrical and electronic parts such as lamp sockets, camera modules, and integrated circuit sealing materials.

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

(1) Composition analysis of liquid crystal polyester resin To 0.1 mg of pulverized liquid crystal polyester resin pellets, 2 μL of tetramethylammonium hydroxide 25% methanol solution was added, and pyrolysis GC / MS measurement was performed using GCMS-QP5050A manufactured by Shimadzu. The composition ratio of each component in the liquid crystal polyester resin was determined.

(2) Melting point (Tm) of liquid crystal polyester resin
Using a differential scanning calorimeter DSC-7 (manufactured by Perkin Elmer), after observing the endothermic peak temperature (Tm ₁ ) observed when the liquid crystalline polyester resin was heated from room temperature under a temperature rising condition of 20 ° C./min. , Held at a temperature of Tm ₁ + 20 ° C. for 5 minutes, further cooled to room temperature under a temperature drop condition of 20 ° C./min, and then endothermic peak temperature observed when the temperature was raised again under a temperature rise condition of 20 ° C./min ( Tm ₂ ) was taken as the melting point. In the following production examples, the melting point (Tm ₂ ) is described as Tm.

(3) Melt viscosity of liquid crystalline polyester resin Melting of liquid crystalline polyester resin under the conditions of Tm + 20 ° C. and shear rate of 1000 / s using Koka-type flow tester CFT-500D (orifice 0.5φ × 10 mm) (manufactured by Shimadzu Corporation) The viscosity was measured.

(4) Thin wall fluidity The pellets obtained in each Example and Comparative Example were hot-air dried at 150 ° C. for 3 hours using a hot-air dryer, and then subjected to a FANUC Co., Ltd. FANUC α30C injection molding machine. The melting point of the liquid crystalline polyester + 20 ° C., the mold temperature is 90 ° C., the injection pressure is set to 100 MPa, the speed is set to the minimum filling speed, the pitch between terminals shown in FIG. 3) A connector molded product having a size of 0.2 mm and outer dimensions of 3 mm width × 2 mm height × 30 mm length 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 0.3 mm) installed on the short surface 2 on one side of the connector molded product. 500 shot molding was performed, and the number of unfilled occurrences was evaluated with respect to the fillability of the wall corner on the gate facing side. The corner portion is a portion where unfilling is likely to occur due to variation in filling amount, and the smaller the number of unfilled occurrences, the better the thin wall fluidity.

(5) Mold fouling property 0.05 parts by weight of a mold release agent (Licowax E, manufactured by Clariant) is added to 100 parts by weight of the pellets obtained in each of the examples and comparative examples, and 150 parts using a hot air dryer. After drying in hot air at 3 ° C. for 3 hours, it was subjected to a FANUC α30C injection molding machine manufactured by FANUC CORPORATION. The resin temperature was the melting point of liquid crystal polyester + 20 ° C., the mold temperature was 90 ° C., and the molding cycle was 12 seconds, 50 mm × 50 mm × A 1 mm thick square plate-like molded product was continuously molded. While confirming the adhesion state of the mold deposit every 100 shots, a maximum of 1000 shots were continuously formed until the adhesion of the mold deposit was confirmed. The number of shots at the time when adhesion to the mold cavity was confirmed was defined as mold contamination. The larger the number of shots where adhesion of mold deposits to the mold cavity is confirmed, the smaller the mold contamination, and the better the mold contamination. If adhesion of mold deposits was not confirmed after 1000 shots of continuous molding, “> 1000” was set.

(6) Dimensional stability A molded product that was molded under the same conditions as in (4) and completely filled was measured for the amount of warpage after heat treatment of the connector molded product. The heat treatment was performed by leaving the connector molded product for 3 minutes in an oven heated to 260 ° C. Note that the amount of warping is determined in the longitudinal direction of the long molded product using a universal projector (V-16A (Nikon)) with the long direction of the molded product standing on a horizontal surface plate. Using a line connecting both ends with a straight line as a reference, the dimensional difference from that to the horizontal surface plate was measured and used as the amount of warpage. FIG. 1B is a conceptual diagram showing the measurement site of the warpage amount in the long molded product, where the AB plane is the reference plane a and the difference from the maximum deformation surface b is the warpage amount. The smaller the amount of warp, the better the dimensional stability.

[Example 1]
In a 5 L reaction vessel equipped with a stirring blade and a distillation pipe, 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 of the total phenolic hydroxyl groups) were allowed to react at 145 ° C. for 1 hour with stirring in a nitrogen gas atmosphere. The jacket temperature of the container was raised from 145 ° C. to 350 ° C. over 4 hours. Thereafter, the polymerization temperature was maintained at 350 ° C., the pressure was reduced to 1.0 mmHg (133 Pa) over 1.0 hour, and the reaction was further continued. When the torque required for stirring reached 8 kg · cm, the polymerization was completed. . Next, the inside of the reaction vessel is pressurized to 1.0 kg / cm ² (0.1 MPa), the polymer is discharged onto a strand through a die having a circular discharge port having a diameter of 10 mm, and pelletized by a cutter. A liquid crystal polyester resin (A-1) was obtained. The obtained liquid crystal polyester resin had a Tm of 327 ° C. and a melt viscosity of 9 Pa · s.

[Example 2]
In a 5 L reaction vessel equipped with a stirring blade and a distillation pipe, 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 , 1,4-cyclohexanedimethanol 3 parts by weight and acetic anhydride 1321 parts by weight (1.07 equivalents of the total phenolic hydroxyl group) were allowed to react at 145 ° C. for 1 hour with stirring in a nitrogen gas atmosphere. The jacket temperature of the container was raised from 145 ° C. to 330 ° C. over 4 hours. Thereafter, the polymerization temperature was maintained at 330 ° C., the pressure was reduced to 1.0 mmHg (133 Pa) over 1.0 hour, and the reaction was further continued. When the torque required for stirring reached 10 kg · cm, the polymerization was completed. . Next, the inside of the reaction vessel is pressurized to 1.0 kg / cm ² (0.1 MPa), the polymer is discharged onto a strand through a die having a circular discharge port having a diameter of 10 mm, and pelletized by a cutter. A liquid crystal polyester resin (A-2) was obtained. The obtained liquid crystal polyester resin had a Tm of 308 ° C. and a melt viscosity of 9 Pa · s.

[Comparative Example 1]
In a 5 L reaction vessel equipped with a stirring blade and a distillation pipe, 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 equivalent of the total phenolic hydroxyl groups) were allowed to react at 145 ° C. for 1 hour with stirring under a nitrogen gas atmosphere, and the jacket temperature of the reaction vessel was increased from 145 ° C. to 350 ° C. The temperature was raised over 4 hours. Thereafter, the polymerization temperature was maintained at 350 ° C., the pressure was reduced to 1.0 mmHg (133 Pa) over 1.0 hour, and the reaction was further continued. When the torque required for stirring reached 8 kg · cm, the polymerization was completed. . Next, the inside of the reaction vessel is pressurized to 1.0 kg / cm ² (0.1 MPa), the polymer is discharged onto a strand through a die having a circular discharge port having a diameter of 10 mm, and pelletized by a cutter. A liquid crystal polyester resin (A-3) was obtained. The obtained liquid crystal polyester resin had a Tm of 328 ° C. and a melt viscosity of 9 Pa · s.

[Comparative Example 2]
In a 5 L reaction vessel equipped with a stirring blade and a distillation pipe, 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 of total phenolic hydroxyl groups) were allowed to react at 145 ° C. for 1 hour with stirring under a nitrogen gas atmosphere, and the jacket temperature of the reaction vessel was increased from 145 ° C. to 330 ° C. The temperature was raised over 4 hours. Thereafter, the polymerization temperature was maintained at 330 ° C., the pressure was reduced to 1.0 mmHg (133 Pa) over 1.0 hour, and the reaction was further continued. When the torque required for stirring reached 10 kg · cm, the polymerization was completed. . Next, the inside of the reaction vessel is pressurized to 1.0 kg / cm ² (0.1 MPa), the polymer is discharged onto a strand through a die having a circular discharge port having a diameter of 10 mm, and pelletized by a cutter. A liquid crystal polyester resin (A-4) was obtained. The obtained liquid crystal polyester resin had a Tm of 310 ° C. and a melt viscosity of 9 Pa · s.

[Comparative Example 3]
In a 5 L reaction vessel equipped with a stirring blade and a distillation pipe, 994 parts by weight of p-hydroxybenzoic acid, 126 parts by weight of 4,4′-dihydroxybiphenyl, 112 parts by weight of terephthalic acid, and an intrinsic viscosity of about 0.6 dl / g 216 parts by weight of polyethylene terephthalate and 960 parts by weight of acetic anhydride (1.10 equivalents of total phenolic hydroxyl groups) were charged, and the mixture was reacted at 145 ° C. for 1 hour with stirring under a nitrogen gas atmosphere. The temperature increased over time. Thereafter, the polymerization temperature was maintained at 320 ° C., the pressure was reduced to 1.0 mmHg (133 Pa) over 1.0 hour, and the reaction was further continued. When the torque required for stirring reached 15 kg · cm, the polymerization was completed. . Next, the inside of the reaction vessel is pressurized to 1.0 kg / cm ² (0.1 MPa), the polymer is discharged onto a strand through a die having a circular discharge port having a diameter of 10 mm, and pelletized by a cutter. A liquid crystal polyester resin (A-5) was obtained. The obtained liquid crystal polyester resin had a Tm of 312 ° C. and a melt viscosity of 9 Pa · s.

[Comparative Example 4]
In a 5 L reaction vessel equipped with a stirring blade and a distillation pipe, 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, 6-hydroxy- 2-Naphthoic acid 85 parts by weight and acetic anhydride 1254 parts by weight (1.05 equivalents of total phenolic hydroxyl groups) were allowed to react at 145 ° C. for 1 hour with stirring in a nitrogen gas atmosphere, and then the jacket temperature of the reaction vessel The temperature was raised from 145 ° C. to 360 ° C. over 4 hours. Thereafter, the polymerization temperature was maintained at 360 ° C., the pressure was reduced to 1.0 mmHg (133 Pa) over 1.0 hour, and the reaction was further continued. When the torque required for stirring reached 10 kg · cm, the polymerization was completed. . Next, the inside of the reaction vessel is pressurized to 1.0 kg / cm ² (0.1 MPa), the polymer is discharged onto a strand through a die having a circular discharge port having a diameter of 10 mm, and pelletized by a cutter. A liquid crystal polyester resin (A-6) was obtained. The obtained liquid crystal polyester resin had a Tm of 350 ° C. and a melt viscosity of 9 Pa · s.

[Comparative Example 5]
In a 5 L reaction vessel equipped with a stirring blade and a distillation pipe, 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, 6-hydroxy-2 -85 parts by weight of naphthoic acid and 1206 parts by weight of acetic anhydride (1.05 equivalents of the total phenolic hydroxyl group) were charged and reacted at 145 ° C for 1 hour with stirring in a nitrogen gas atmosphere. The temperature was raised from 145 ° C. to 350 ° C. over 4 hours. Thereafter, the polymerization temperature was maintained at 350 ° C., the pressure was reduced to 1.0 mmHg (133 Pa) over 1.0 hour, and the reaction was further continued. When the torque required for stirring reached 10 kg · cm, the polymerization was completed. . Next, the inside of the reaction vessel is pressurized to 1.0 kg / cm ² (0.1 MPa), the polymer is discharged onto a strand through a die having a circular discharge port having a diameter of 10 mm, and pelletized by a cutter. A liquid crystal polyester resin (A-7) was obtained. The obtained liquid crystal polyester resin had a Tm of 333 ° C. and a melt viscosity of 9 Pa · s.

[Comparative Example 6]
In a 5 L reaction vessel equipped with a stirring blade and a distillation tube, 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 part (1.05 equivalents of total phenolic hydroxyl groups) was allowed to react at 145 ° C. for 1 hour with stirring under a nitrogen gas atmosphere, and the jacket temperature of the reaction vessel was changed from 145 ° C. to 340 ° C. over 4 hours. The temperature rose. Thereafter, the polymerization temperature was maintained at 340 ° C. and the pressure was reduced to 1.0 mmHg (133 Pa) over 1.0 hour, and then the reaction was continued, and the polymerization was completed when the torque required for stirring reached 10 kg · cm. . Next, the inside of the reaction vessel is pressurized to 1.0 kg / cm ² (0.1 MPa), the polymer is discharged onto a strand through a die having a circular discharge port having a diameter of 10 mm, and pelletized by a cutter. A liquid crystal polyester resin (A-8) was obtained. The obtained liquid crystal polyester resin had a Tm of 328 ° C. and a melt viscosity of 9 Pa · s.

[Comparative Example 7]
In a 5 L reaction vessel equipped with a stirring blade and a distillation pipe, 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 phenolic hydroxyl group) were allowed to react at 145 ° C. for 1 hour with stirring under a nitrogen gas atmosphere, and then the jacket temperature of the reaction vessel was changed from 145 ° C. to 360 ° C. The temperature was raised over 4 hours. Thereafter, the polymerization temperature was maintained at 360 ° C., the pressure was reduced to 1.0 mmHg (133 Pa) over 1.0 hour, the reaction was continued, and the polymerization was completed when the torque required for stirring reached 10 kg · cm. Next, the inside of the reaction vessel is pressurized to 1.0 kg / cm ² (0.1 MPa), the polymer is discharged onto a strand through a die having a circular discharge port having a diameter of 10 mm, and pelletized by a cutter. A liquid crystal polyester resin (A-9) was obtained. The obtained liquid crystal polyester resin had a Tm of 350 ° C. and a melt viscosity of 9 Pa · s.

[Comparative Example 8]
In a 5 L reaction vessel equipped with a stirring blade and a distillation pipe, 994 parts by weight of p-hydroxybenzoic acid, 126 parts by weight of 4,4′-dihydroxybiphenyl, 112 parts by weight of terephthalic acid, and an intrinsic viscosity of about 0.6 dl / g 216 parts by weight of polyethylene terephthalate, 3 parts by weight of 1,4-cyclohexanedimethanol and 963 parts by weight of acetic anhydride (1.10 equivalents of total phenolic hydroxyl groups) were charged and reacted at 145 ° C. for 1 hour with stirring in a nitrogen gas atmosphere Then, the temperature was raised from 145 ° C. to 320 ° C. over 4 hours. Thereafter, the polymerization temperature was maintained at 320 ° C., the pressure was reduced to 1.0 mmHg (133 Pa) over 1.0 hour, and the reaction was further continued. When the torque required for stirring reached 15 kg · cm, the polymerization was completed. . Next, the inside of the reaction vessel is pressurized to 1.0 kg / cm ² (0.1 MPa), the polymer is discharged onto a strand through a die having a circular discharge port having a diameter of 10 mm, and pelletized by a cutter. A liquid crystal polyester resin (A-10) was obtained. The obtained liquid crystal polyester resin had a Tm of 311 ° C. and a melt viscosity of 9 Pa · s.

Table 1 shows the results of composition analysis performed on the pellets obtained in Examples 1 and 2 and Comparative Examples 1 to 8 by the method described in (1) above, and the results of evaluations (4) to (6). It is shown in 1.

Subsequently, additives (a-1) to (a′-5) are further melt-kneaded with the liquid crystal polyester resins (A-3) to (A-9) obtained as described above to obtain liquid crystal polyester resins. Produced.

The compounds used in each example and comparative example are shown below.
(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) synthesized according to Production Example 1 below (Two hydroxyl groups of 1,4-cyclohexanedimethanol) And a compound in which the carboxyl group of p-hydroxybenzoic acid is ester-bonded)
(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.

A production example of (a-3) is as follows.
[Production Example 1]
Put 75 parts by weight of p-hydroxybenzoic acid, 43 parts by weight of 1,4-cyclohexanedimethanol, and 4 drops of concentrated sulfuric acid into toluene, and distill off the water generated by the reaction azeotropically to remove only toluene. Refluxed and heated for 3 hours. After cooling to room temperature, methanol was added and the resulting solution was filtered. Furthermore, it was washed several times with methanol and dried to obtain (a-3).

Examples 3-12, Comparative Examples 9-12
Using Toshiba Machine's TEM35B type twin screw extruder equipped with a side feeder, a side feeder is installed at C3 part of cylinder C1 (former feeder side heater) to C6 (die side heater), and a vacuum vent is provided at C5 part. Was installed. A screw arrangement in which kneading blocks were incorporated in C2 part and C4 part was used. Liquid crystal polyester resins (A-3) to (A-9) and additives (a-1) to (a'-5) were charged from the feed feeder in the blending amounts shown in Table 2, and the cylinder temperature was set to liquid crystal polyester. The melting point of the resin + 10 ° C., the screw rotation speed was set to 200 rpm, and melt kneading was performed to obtain pellets. The obtained liquid crystal polyester resin pellets were hot-air dried at 150 ° C. for 3 hours using a hot-air dryer, and then evaluated (1) and (4) to (6) above. The results are shown in Table 2.

Subsequently, an inorganic filler was blended into the liquid crystal polyester resins (A-1) to (A-10) obtained as described above to prepare liquid crystal polyester resins. The inorganic fillers (b-1) to (b-3) used in the examples and comparative examples are shown below.
(B-1): Mica “NJ-030” manufactured by Yamaguchi Mica Co., Ltd.
(B-2): Talc “RL217” manufactured by Fuji Talc Industry Co., Ltd.
(B-3): EPG (70MD-01N) / P9W manufactured by Nippon Electric Glass Co., Ltd.

Examples 13 and 14, Comparative Examples 13 to 20
Liquid crystalline polyester resins (A-1) to (A-10) were charged from the feed-in feeder at the blending amounts shown in Table 3, and the inorganic fillers (b-1) to (b-3) were blended as shown in Table 3. The pellets were obtained by melt-kneading in the same manner as in Examples 3 to 12 and Comparative Examples 9 to 12 except that they were charged from the side feeder, and the evaluations (4) to (6) were performed. The results are shown in Table 3.

Examples 15 to 25, Comparative Examples 21 to 24
The pellets were melt-kneaded 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 added from the side feeder in the amounts shown in Table 4. The above (1) and (4) to (6) were evaluated. The results are shown in Table 4.

From the results shown in Tables 1 to 4, it can be seen that the liquid crystal polyester resin and the liquid crystal polyester resin composition of the present invention are excellent in thin wall fluidity and dimensional stability while suppressing mold contamination. Therefore, it can be said that it is suitable for use in electrical / electronic parts and mechanical parts applications such as connectors, relays, switches, coil bobbins, lamp sockets, camera modules, integrated circuit sealing materials having a thin box shape or cylindrical shape. .

Since 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, a connector, relay, switch, coil bobbin having a thin-walled box shape or cylindrical shape It is suitable for electrical / electronic parts and machine parts such as lamp sockets, camera modules and integrated circuit sealing materials.

1 Long surface 2 Short surface 3 Length (30mm)
4 Height (2mm)
5 width (3mm)
6 Distance between pitches (0.4mm)
7 Minimum wall thickness (0.2mm)
8 Saw amount G1 Pin gate a Reference surface b Maximum deformation surface

Claims

15 to 80 mol% of structural units derived from aromatic hydroxycarboxylic acid, 7 to 40 mol% of structural units derived from aromatic diol, 100 mol% of all structural units of the liquid crystalline polyester resin, aromatic dicarboxylic acid A liquid crystal polyester resin containing 7 to 40 mol% of structural units derived from the above and 0.01 to 5 mol% of at least one structural unit selected from the following structural units (I) and (II).
The liquid crystalline polyester resin includes the following structural unit (III) as a structural unit derived from an aromatic hydroxycarboxylic acid, and includes the following structural unit (IV) as a structural unit derived from an aromatic dicarboxylic acid, 2. The liquid crystal polyester resin according to claim 1, wherein the total of structural units (IV) is 60 to 80 mol% with respect to 100 mol% of all structural units of the liquid crystal polyester resin.
The liquid crystal polyester resin contains the following structural unit (V) as a structural unit derived from an aromatic diol, and the structural unit (V) is 2 to 20% with respect to 100 mol% of all structural units of the liquid crystal polyester resin. The liquid crystal polyester resin according to claim 1 or 2.
The liquid crystal polyester resin according to any one of claims 1 to 3, wherein at least one structural unit selected from the structural units (I) and (II) contains the structural unit (II) as an essential component.
It is obtained by blending a liquid crystal polyester resin not containing a structural unit selected from the structural units (I) and (II) and a compound having at least one structure selected from the structural units (I) and (II). The liquid crystal polyester resin according to claim 1, wherein the liquid crystal polyester resin is used.
A liquid crystal polyester resin not containing a structural unit selected from the structural units (I) and (II) and a compound having at least one structure selected from the structural units (I) and (II) are melt-kneaded. 5. A method for producing a liquid crystal polyester resin according to any one of 1 to 4.
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.
A molded article comprising the liquid crystal polyester resin according to any one of claims 1 to 5 or the liquid crystal polyester resin composition according to claim 7.
The molded article according to claim 8, wherein the molded article is selected from the group consisting of a connector, a relay, a switch, a coil bobbin, a lamp socket, a camera module, and an integrated circuit sealing material.