WO2005066403A1

WO2005066403A1 - Ultrafine polytrimethylene terephthalate conjugate fiber for artificial leather and manufacturing method thereof

Info

Publication number: WO2005066403A1
Application number: PCT/KR2005/000071
Authority: WO
Inventors: Tae Hwan Oh; Young Geun Choi; Do Kyoon Kim; Seung Woo Rew; Sun Woo Kim; Jae Hong Lee
Original assignee: Huvis Corporation
Priority date: 2004-01-12
Filing date: 2005-01-10
Publication date: 2005-07-21
Also published as: KR20050073909A; TW200530440A

Abstract

Disclosed herein is an ultrafine polytrimethylene terephthalate conjugate fiber for artificial leather, which is obtained by mixing polytrimethylene terephthalate and alkali-soluble polyester using a distribution plate of a bi-component spinning pack, followed by spinning through a spinnerette, to obtain a spun grey yarn, which is then processed into a nonwoven fabric or woven/knit fabric, in which only the soluble polyester is dissolved in an aqueous alkali solution. The polytrimethylene terephthalate conjugate fiber of the current invention is advantageous of having alkali resistance and softness to the touch similar to nylon due to having a low Young’s modulus, and also, can be uniformly dyed at a low temperature under atmospheric pressure. Therefore, the artificial leather resulting from such an ultrafine conjugate fiber can exhibit high softness to the touch and deep dyeability. In addition, a method of manufacturing the ultrafine polytrimethylene terephthalate conjugate fiber is provided.

Description

ULTRAFINE POLYTRIMETHYLENE TEREPHTHALATE CONJUGATE FIBER FOR ARTIFICIAL LEATHER AND MANUFACTURING METHOD THEREOF

Technical Field

The present invention relates, generally, to polytrimethylene terephthalate conjugate fibers for artificial leather. More particularly, the present invention relates to an ultrafine polytrimethylene terephthalate conjugate fiber for artificial leather and a method of manufacturing the same, in which polytrimethylene terephthalate (hereinafter, abbreviated as ^PTT' ) and alkali-soluble polyester are mixed using a distribution plate of a bi-component spinning pack, and spun through a spinnerette, to obtain a spun grey yarn, which is then processed into a nonwoven fabric or woven/knit fabric, in which the soluble polyester is dissolved in an aqueous alkali solution, thereby obtaining an ultrafine PTT conjugate fiber suitable for use in manufacturing functional artificial leather being very soft to the touch and deeply dyeable at a low temperature under atmospheric pressure.

Background Art

Generally, ultrafine conjugate fibers composed of PTT, which are disclosed m Korean Patent Laid-open Publication Nos. 1999-0076028 and 1999-0076036, have copolymeπzed polyester and polyethylene, respectively, other components in addition to PTT. However, in the case where polyethylene is used as a sea component, it has a large difference in melting point from polyethylene terephthalate or polytrimethylene, serving as an island component. Thus, the difference in melt viscosity between the island component and the sea component increases, resulting in poor spinning processability. Further, the thusly obtained conjugate fiber is disadvantageous because it has lower strength after removal of the sea component, compared to before removal of the sea component.

Disclosure of the Invention

Accordingly, the present invention has been made keeping m mind the above problems occurring in the related art, and an object of the present invention is to provide an ultrafine PTT conjugate fiber for artificial leather having a fineness of 0.1-0.001 denier, which can be used to manufacture artificial leather being very soft to the touch and deeply dyeable. Another object of the present invention is to provide a method of manufacturing the ultrafine PTT conjugate fiber. The above objects could be accomplished by a provision of an ultrafine PTT conjugate fiber for artificial leather, which comprises PTT having an intrinsic viscosity of 0.8-1.2 as a matrix component and alkali- soluble polyester having an intrinsic viscosity of 0.4-0.7 as a soluble component, and has a matrix component/soluble component weight ratio of 40/60-90/10. In addition, the present invention provides a method of manufacturing an ultrafine PTT conjugate fiber for artificial leather, which comprises individually extruding PTT having an intrinsic viscosity of 0.8-1.2 as a matrix component and alkali-soluble polyester having an intrinsic viscosity of 0.4-0.7 as a soluble component at a matrix component/soluble component weight ratio of 40/60-90/10 using an extruder, feeding the extruded components into a spinning block, mixing the fed components using a distribution plate of a bi-component spinning pack, spinning the mixture at a drawing ratio of 1.5-3.5 at a spinning speed of 2,500-5,000 m/min while performing a draw heat-treatment, to obtain a grey yarn, and treating the grey yarn with an alkali, thereby manufacturing an ultrafine PTT conjugate fiber having a fineness of 0.1- 0.001 denier and retaining 90% or more of its strength after the alkali treatment.

Best Mode for Carrying Out the Invention

Hereinafter, a detailed description will be given of the present invention. According to the present invention, an ultrafine PTT conjugate fiber for artificial leather having a fineness of 0.1-0.001 denier is manufactured by individually extruding PTT as a matrix component constituting the fiber and soluble polyester as a soluble component at a predetermined ratio using an extruder, followed by feeding the extruded components into a spinning block, uniformly mixing them using a distribution plate of a bi-component spinning pack, and draw heat-treating the mixture while spinning it through spinnerette holes, to obtain a grey yarn, in which the soluble polyester is dissolved in an alkali. The soluble polyester results from copolymerization of polyethylene terephthalate and 3-20 mol% any one selected from among polyethyleneglycol, 5-sodιum sulfoisophthalic acid, or combinations thereof. PTT and soluble polyester of the bi-component type conjugate fiber are individually extruded at a predetermined ratio using an extruder mounted to a typical spinning machine for bi-component spinning, fed into a spinning block through a gear pump, mixed using a distribution plate of a spinning pack, spun through spinnerette holes, and subjected to draw heat-treatment, to obtain a drawn yarn as a conjugate fiber having a cross- section in which the PTT component is arranged to a fiber axis direction in the soluble polyester. As such, the matrix component A and the soluble component B of the yarn which is in the form of soluble polyester surrounding the PTT fiber have a weight ratio of 40/60-90/10, and preferably, 60/40-80/20, in consideration of workability and fineness of the matrix component after the soluble component is dissolved m an alkali. If the ratio of the soluble component exceeds 60, the fineness may decrease. However, since a large amount of the soluble component should be dissolved, an excessive amount of alkali is used. On the other hand, if the ratio of the soluble component is less than 10, the resultant yarn has high fineness, resulting in artificial leather that is hard to the touch. Further, after the sea component is removed from the grey yarn, the temperature of the extruder used to extrude each component and the spinning temperature are controlled, whereby the strength after weight loss treatment of the grey yarn can be prevented from reduction. In this case, it is preferable that the temperature of the extruder be in the range of 245-285°C. Also, the spinning temperature preferably ranges from 250 to 285°C. When the temperature of the extruder is less than 245°C, the melting process is incompletely performed. On the other hand, if the above temperature is higher than 285°C, pyrolysis occurs due to the high temperature, thus decreasing the molecular weight of the polymer. Also, if the spinning temperature is lower than 250°C, spinning processability becomes poor. Meanwhile, if the spinning temperature is higher than 285°C, properties of the grey yarn are deteriorated. A better understanding of the present invention may be obtained through the following examples which are set forth to illustrate, but are not to be construed as the limit of the present invention. Various properties were measured according to the following procedures. * Sense of Touch: According to a quantitative method for sensory evaluation, the touch of the wrap knit fabric sample after dissolution in an alkali was evaluated by five experts, and the results were classified into five grades: better, good, normal, bad, and worse. Specifically, the better grade was assigned when four or more experts judged the sample to be soft, the good grade when three experts judged the sample to be soft, the normal grade when two experts judged the sample to be soft, and the bad grade when one or less experts judged the sample to be soft. * Dyeability: The wrap knit fabric sample was dyed with a dye at 100°C under atmospheric pressure, washed with water, and then evaluated for dyeability on a scale from 1 to 5 on the basis of a standard color table, in which the higher the value, the better the dyeability. * Strength Maintenance: The strength maintenance of grey yarn sample after weight loss treatment using an alkali was determined, as represented by Equation 1, below: Equation 1 Strength Maintenance (%) = (A/B) x 100 Wherein, A is the strength of a sea-island type ultrafine yarn after treatment with an aqueous caustic soda solution (1% concentration) at 95°C for 30 min, and B is the strength of a sea-island type ultrafine yarn before treatment with the aqueous caustic soda solution. * Tensile Strength: The strength of a grey yarn sample was measured under the conditions of a distance between two holding points of 50 mm and a tensile speed of 12 mm/min using a tensile strength tester, and then the value thereof was divided by the fineness of the sample. * Fineness: The grey yarn sample was wound in 90 rounds (90 m) using a wrap reel (1 m/round) . The wound sample was weighed, and then the weight thereof was multiplied by 100.

Example 1 Soluble polyester having an intrinsic viscosity of about 0.5, as a soluble component, and PTT having an intrinsic viscosity of about 1.0, as a matrix component, were individually extruded at a soluble component/matrix component weight ratio of 30/70 at a temperature of an extruder as shown in Table 1, below, fed into a spinning block, and then uniformly mixed using a distribution plate of a bi-component spinning pack. The resultant mixture was subjected to bi-component spinning at a spinning temperature of 270°C and a spinning speed of 4000 m/min through the total of 48 spinnerette holes each having a size of 3 denier, to obtain a grey yarn. The grey yarn was subjected to weight loss treatment using an alkali, to maufacture an ultrafine PTT conjugate fiber for artificial leather having a fineness of 0.06 denier. The conjugate fiber was wrap knitted using a wrap knitting machine, to obtain a wrap knit fabric. Subsequently, the soluble polyester in the wrap knit fabric was dissolved in an alkali, whereby only the ultrafine matrix component remained in the wrap knit fabric, followed by being measured for various properties. The results are given in Table 1, below.

Example 2 The grey yarn and the wrap knit fabric were manufactured in the same conditions and processes as in Example 1, with the exception that the soluble component/matrix component weight ratio was changed to 20/80. Various properties were measured. The results are given in Table 1, below.

Example 3 The grey yarn and the wrap knit fabric were manufactured in the same conditions and processes as in Example 1, with the exception that the spinning process was performed using a total of 72 spinnerette holes. Various properties were measured. The results are given in Table 1, below.

Example 4 The grey yarn and the wrap knit fabric were manufactured in the same conditions and processes as in Example 1, with the exception that the spinning temperature was changed to 265°C. Various properties were measured. The results are given in Table 1, below.

Example 5 The grey yarn and the wrap knit fabric were manufactured in the same conditions and processes as in Example 1, with the exception that the spinning temperature was changed to 275°C. Various properties were measured. The results are given in Table 1, below.

Comparative Example 1 The grey yarn and the wrap knit fabric were manufactured in the same conditions and processes as in

Example 1, with the exception that the temperature of the extruder for use in extruding the matrix component was changed to 285°C. Various properties were measured. The results are given in Table 1, below.

TABLE 1

As is apparent from Table 1, the ultrafine PTT conjugate fiber for artificial leather having a fineness of 0.1-0.001 denier, which is suitable for use in manufacturing functional artificial leather being very soft to the touch and deeply dyeable at a low temperature under atmospheric pressure, can be obtained by mixing the polyester component having high solubility with the matrix component using the distribution plate of the bi-component spinning pack, followed by being spun through the spinnerette, to obtain a spun grey yarn, which is then processed into the nonwoven fabric or woven/knit fabric, in which only the soluble polyester is dissolved in an aqueous alkali solution.

Industrial Applicability

As described hereinbefore, the present invention provides an ultrafine PTT conjugate fiber and a manufacturing method thereof. In the present invention, the ultrafine PTT conjugate fiber, which has a fineness of 0.1- 0.001 denier, can be manufactured by mixing the polyester component having high solubility with the matrix component using the distribution plate of the bi-component spinning pack, followed by being spun through the spinnerette, to obtain a spun grey yarn, which is then processed into nonwoven fabric or woven/knit fabric, in which only the soluble polyester is dissolved in an aqueous alkali solution. The ultrafine PTT conjugate fiber of the present invention can be used to manufacture functional artificial leather being highly soft to the touch and deeply dyeable at a low temperature under atmospheric pressure. Although the preferred embodiments of the present invention have been disclosed for illustrative purposes, those skilled in the art will appreciate that various modifications, additions and substitutions are possible, without departing from the scope and spirit of the invention as disclosed in the accompanying claims.

Claims

1. An ultrafine polytrimethylene terephthalate conjugate fiber for artificial leather, comprising polytrimethylene terephthalate having an intrinsic viscosity of 0.8-1.2 as a matrix component and alkali- soluble polyester having an intrinsic viscosity of 0.4-0.7 as a soluble component, and having a matrix component/soluble component weight ratio of 40/60-90/10 and strength maintenance of 90% or more after alkali treatment.

2. The conjugate fiber as set forth in claim 1, wherein the conjugate fiber has a fineness of 0.1-0.001 denier after alkali treatment.

3. The conjugate fiber as set forth in claim 1, wherein the alkali-soluble polyester as the soluble component is obtained by copolymerizing polyethylene terephthalate with 3-20 mol% polyethylene glycol and/or 5- sodium sulfoisophthalic acid. . A method of manufacturing an ultrafine polytrimethylene terephthalate conjugate fiber for artificial leather, comprising: individually extruding polytrimethylene terephthalate having an intrinsic viscosity of 0.8-1.2 as a matrix component and alkali-soluble polyester having an intrinsic viscosity of 0.

4-0.7 as a soluble component at a matrix component/soluble component weight ratio of 40/60-90/10 using an extruder; feeding the extruded components into a spinning block; mixing the fed components using a distribution plate of a bi-component spinning pack; spinning the mixture at a drawing ratio of 1.5-3.5 and a spinning speed of 2,500-5,000 m/min while performing a draw heat-treatment, to obtain a grey yarn; and treating the grey yarn with an alkali, thereby manufacturing an ultrafine polytrimethylene terephthalate conjugate fiber having a fineness of 0.1-0.001 denier and strength maintenance of 90% or more after the alkali treatment.

5. The method as set forth in claim 4, wherein the extruder is used at 245-285°C, and the spinning is performed at 250-285°C.

6. The method as set forth in claim 4, wherein the matrix component/soluble component weight ratio is in a range of 60/40-80/20.