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Liquid-crystalline polyester and process for preparing same

A manufacturing method and technology of liquid crystallinity, applied in the field of liquid crystal polyester, can solve the problems of strength reduction, resin metering time, difference in injection peak pressure, high temperature sensitivity, and achieve the effect of excellent strength

Active Publication Date: 2013-09-04
TORAY IND INC
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

However, since the liquid crystalline polyester has high temperature sensitivity during melting, the following problems may arise
The following problems may occur, that is, the difference in resin metering time and injection peak pressure during injection molding may cause a decrease in productivity, or the strength of small thin-walled molded products represented by the winding wire strength of insulators may decrease, or the polymer itself may cause problems. Dimensions change greatly before and after heating due to residual stress during molding

Method used

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  • Liquid-crystalline polyester and process for preparing same
  • Liquid-crystalline polyester and process for preparing same
  • Liquid-crystalline polyester and process for preparing same

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1～6、 comparative example 1～5

[0141] The particles of the liquid crystalline polyester (a-1 to a-6, b-1 to b-5) obtained in each production example were dried with hot air. The liquid crystalline polyesters (a-1) to (a-6) after hot air drying were used as the liquid crystalline polyesters of Examples 1 to 6, respectively. In addition, the liquid crystalline polyesters (b-1) to (b-5) after hot air drying were set as the liquid crystalline polyesters of Comparative Examples 1 to 5, respectively. Regarding the liquid crystalline polyesters of Examples 1 to 6 and Comparative Examples 1 to 5, evaluations (1) to (3) shown below were performed. The results are shown in Table 2.

[0142] (1) Precision molding stability evaluation

[0143] The liquid crystalline polyester was supplied to a FANACK α30C injection molding machine (FANACK screw diameter 28 mm), the cylinder temperature was set to the melting point of the liquid crystalline polyester + 10°C, the screw speed was set to 150 rpm, and the back pressure wa...

Embodiment 7～18、 comparative example 6～16

[0157] The liquid crystalline polyesters (a-1 to a-6, b-1 to b-5) obtained in each production example were charged from a hopper using a TEM35B twin-screw extruder manufactured by Toshiba Machinery Co., Ltd. equipped with a side feeder. The fillers (c-1 to c-4) were added from the side in the amount shown in Table 3 with respect to 100 parts by weight of the liquid crystalline polyester, and the temperature of the cylinder was set at the melting point of the liquid crystalline polyester + 10°C. Melt kneading is carried out to form pellets. The obtained pellets of the liquid crystalline polyester resin composition were dried with hot air. Thus, the liquid crystalline polyester resin compositions of Examples 7 to 18 and Comparative Examples 6 to 16 were obtained. About the obtained liquid crystalline polyester resin compositions of Examples 7-18 and Comparative Examples 6-16, the evaluation of said (1)-(3) was performed. In addition, (1) in the precision molding stability eval...

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Abstract

The invention relates to a liquid-crystalline polyester characterized by being composed of structural units (I), (II), (III), (IV) and (V), wherein the content of structural units (I) is 68 to 80mol% relative to the sum total of structural units (I), (II) and (III); the content of structural units (II) is 55 to 75mol% relative to the sum total of structural units (II) and (III); the content of structural units (IV) is 60 to 85mol% relative to the sum total of structural units (IV) and (V); the total molar content of structural units (II) and (III) is substantially equal to that of structural units (IV) and (V); and the deltaS (entropy of melting) is 1.0 to 3.* 10<-3>J / g.K as defined by formula [1]: deltaS(J / gK) = deltaHm(J / g) / Tm(K) [wherein Tm is an endothermic peak temperature (Tm3) observed in differential scanning calorimetry of the liquid-crystalline polyester, and deltaHm is the area (deltaHm3) of the endothermic peak at the Tm3, said Tm3 being determined by heating a specimen of the liquid-crystalline polyester from room temperature at a heating rate of 20 DEG C / min to determine an endothermic peak temperature (Tm1), keeping the specimen at a temperature of Tm1+20 DEG C for 5 minutes, cooling the specimen briefly to room temperature at a cooling rate of 20 DEG C / min, heating the specimen again at a heating rate of 20 DEG C / min to determine another endothermic peak temperature (Tm2), keeping the specimen at a temperature of Tm1+20 DEG C for 5 minutes, cooling the specimen briefly to room temperature at a cooling rate of 20 DEG C / min, and then heating the specimen again at a heating rate of 20 DEG C / min to determine another endothermic peak temperature, namely, Tm3].

Description

technical field [0001] The present invention relates to a liquid crystalline polyester excellent in precision molding stability represented by differences in resin metering time and injection peak pressure during injection molding, dimensional stability during reflow, and strength of small thin-walled molded articles, its production method, A resin composition and a molded article obtained from the liquid crystalline polyester. Background technique [0002] Liquid crystal polyester can improve heat resistance, fluidity, dimensional stability, electrical characteristics, etc. by controlling its own crystallinity by using molecular structure, production method, etc., and is mainly used in small precision molded products for electrical and electronic applications Demand expands. However, since liquid crystalline polyester has high temperature sensitivity when melted, the following problems may arise. The following problems may occur, that is, the difference in resin metering ...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C08G63/60C08K3/00C08L67/04
CPCC08G63/605C08G63/78C08K7/14C09K19/3809C08L67/03C08G63/60C08K3/00C08L67/04C08J5/00C08G63/19
Inventor 宫本皓平滨口美都繁梅津秀之
Owner TORAY IND INC