PROCESS FOR PRODUCING SEMI-PROCESSED PRODUCT FOR AUTOMOBILE EQUIPMENT

Abstract

Provided is a method for producing a semi-product for automobile equipment, the semi-processed product being moldable in a relatively broad range of heating temperatures and being capable of obtaining a final product with high stiffness. In the method for producing a semi-processed product for automobile equipment, needle punching is performed on a fiber web in which core-sheath composite fibers are accumulated, and the core-sheath composite fibers are three-dimensionally interlaced together. The core portion of the core-sheath composite fibers comprises a copolymer of ethylene glycol and terephthalic acid. The sheath portion of the core-sheath composition fibers comprises a copolymer including ethylene glycol, adipic acid and terephthalic acid. The weight ratio of core portion to sheath portion in the core-sheath composite fibers is 1 to 3:1. The core portion and the sheath portion are disposed concentrically. In the fiber web, the core-sheath composite fibers are bonded together by softening or melting the sheath portion.

Claims

1. A process for producing a semi-processed product for automobile equipment, comprising needle-punching a fiber web in which core-sheath composite fibers are accumulated and the core-sheath composite fibers are three dimensionally interlaced together, wherein the core portions of the core-sheath composite fibers comprise a copolymer of ethylene glycol and terephthalic acid and the sheath portions comprise a copolymer including ethylene glycol, adipic acid and terephthalic acid.

2. The process according to claim 1, wherein the sheath portions comprise a copolymer of ethylene glycol, adipic acid, terephthalic acid and diethylene glycol.

3. The process according to claim 1, wherein a weight ratio of core portion:sheath portion is core portion:sheath portion=1 to 3:1.

4. The process according to claim 1, wherein the core portion and the sheath portion in the core sheath composite fiber are concentrically disposed.

5. The process according to claim 1, wherein the core-sheath composite fiber is either a core sheath composite continuous fiber or a core sheath composite staple fiber.

6. The process according to claim 1, wherein the core-sheath composite fibers are bonded together by softening or melting the sheath portions.

7. The process according to claim 1, wherein the automobile equipment is an undercover covering an underside of an automobile.

8. A process for producing automobile equipment, comprising the following steps: a step of obtaining a fiber web in which core-sheath composite fibers are accumulated, wherein the core portions of the core-sheath composite fibers comprise a copolymer of ethylene glycol and terephthalic acid and the sheath portions comprise a copolymer including ethylene glycol, adipic acid and terephthalic acid, a step of needle-punching a fiber web and three dimensionally interlacing the core-sheath composite fibers to obtain the semi-processed product for automobile equipment, a step of heating and compressing the semi-processed product for automobile equipment.

9. The process for producing automobile equipment according to claim 8, wherein the sheath portion is formed from ethylene glycol, adipic acid, terephthalic acid, isophthalic acid and diethylene glycol.

Description

EXAMPLES

Example 1

[0014] A copolymer having a melting point of 250 C. was prepared from ethylene glycol and terephthalic acid as a core portion. Another copoymer having a melting point of 200 C. was prepared from ethylene glycol, diethylene glycol, adipic acid, terephthalic acid and isophthalic acid as a sheath portion. The diol components contained 98.8 mole % of ethylene glycol and 1.2 mole % of diethylene glycol. The dicarboxylic acid components contained 18.8 mole % of adipic acid, 78.0 mole % of terephthalic acid and 3.2 mole % of isophthalic acid. Both of the core portion and the sheath portion were put in a spinning machine having composite spinning holes and melt-spun to obtain core sheath composite continuous fibers. A weight ratio of core portion and sheath portion was core portion:sheath portion=7:3. After obtaining the core sheath composite continuous fibers, they were introduced into an air sucker equipped with a lower portion of the spinning machine and high speed drawn and thinned, followed by fiber opening using an art-known fiber opening apparatus and collecting them on a moving screen conveyer to obtain a fiber web. The resulting fiber web was provided between a pair of heating rolls to soften the sheath portions, thus bonding the core sheath composite continuous fibers together, which were moved to a needle punch machine and needle punched with a punch density of 90 punches/cm.sup.2 to obtain a semi-processed product for automotive equipment having a weight of 525 g/m.sup.2.

Comparative Example 1

[0015] The copolymer obtained in Example 1 was prepared as the core portion. A terpolymer having a melting point of 230 C. formed from ethylene glycol, terephthalic acid and isophthalic acid was prepared. Both of the core portion and the sheath portion were put in a spinning machine having composite spinning holes and melt-spun to obtain core sheath composite continuous fibers. A weight ratio of core portion and sheath portion was core portion:sheath portion=6:4. After obtaining the core sheath composite continuous fibers, they were introduced into an air sucker equipped with a lower portion of the spinning machine and high speed drawn and thinned, followed by fiber opening using an art-known fiber opening apparatus and collecting them on a moving screen conveyer to obtain a fiber web. The resulting fiber web was provided between a pair of heating rolls to soften the sheath portions, thus bonding the core sheath composite continuous fibers together, which were moved to a needle punch machine and needle punched with a punch density of 90 punches/cm.sup.2 to obtain a semi-processed product for automotive equipment having a weight of 500 g/m.sup.2.

Comparative Example 2

[0016] A core sheath composite staple fiber (Product Number 2080 available from Unitika Co., Ltd., Fineness of 4 dtex, Fiber length of 51 mm, core portion:sheath portion=1:1, sheath portion having a melting point of 200 C.) was prepared. The core portion of the core sheath composite staple fiber was same with the copolymer employed in Example 1 and the sheath portion was a terpolymer formed from ethylene glycol, terephthalic acid and isophthalic acid, but a content of isophthalic acid was higher and its melting point was low. The core sheath staple fibers were open-fibered with a carding apparatus and collected to obtain a fiber web. The resulting fiber web was immediately moved to a needle punch machine and needle punched with a punch density of 90 punches/cm.sup.2 to obtain a semi-processed product for automotive equipment having a weight of 500 g/m.sup.2.

[0017] The semi-processed products for automobile equipment obtained in Example 1 and Comparative Examples 1 and 2 were passed between a pair of metal plates both heated and heated and compression molded with a pressure of 30 kPa for 1 minute. The heated metal plates were controlled to nine temperatures, i.e. 120 C., 130 C., 140 C., 150 C., 160 C., 180 C., 200 C., 210 C. and 220 C. The results are as follow: The product obtained in Example 1 could be suitably shaped at a temperature of 150 to 210 C. to obtain an accessary having high rigidity. It could be shaped at a temperature of 120 to 140 C., but its rigidity was a little poor. The semi-processed product obtained in Comparative Example 1 could not be shaped at a temperature of 120 to 180 C. and could be shaped at a temperature of 200 to 220 C., but its stiffness was poor. The semi-processed product obtained in Comparative Example 2 could be suitably shaped at a temperature of 160 to 180 C. to obtain an accessary. It could be shaped at a temperature of 120 to 150 C. or 200 to 220 C., but its rigidity was poor.