ARTIFICIAL LEATHER COMPOSED OF DOPE-DYED POLYESTER FIBER AND METHOD OF PREPARING THE SAME

Abstract

An artificial leather composed of a dope-dyed polyester fiber is provided. The artificial leather includes a carbon black in island component of a sea-island composite fiber and a polyurethane polymer elastomer. It is possible to improve the fastness to light and the fastness to rubbing at medium and deeper color, and at the same time, to have a luxuriously high quality and to reduce the amount of dye used in the production of artificial leather.

Claims

1. An artificial leather composed of dope-dyed polyester fiber, in which a black polymer elastomer is impregnated and a dispersion dye is dyed in a nonwoven fabric comprising sea-island type composite fiber of which an island component is black dope-dyed polyester.

2. The artificial leather composed of dope-dyed polyester fiber of claim 1, wherein the black dope-dyed polyester comprises 0.08 to 3.00% by weight of a carbon black.

3. The artificial leather composed of dope-dyed polyester fiber of claim 1, wherein the black polymer elastomer comprises 1 to 6% by weight of a carbon black.

4. The artificial leather composed of dope-dyed polyester fiber of claim 1, which has fastness to light of at least grade 4, fastness to dry rubbing of at least grade 4 and fastness to wet rubbing of at least grade 4 according to ISO 105-B06: 1998 method (condition 5).

5. A method of preparing artificial leather composed of dope-dyed polyester fiber comprising: preparing staple fiber from sea-island type composite fiber filament composed of black dope-dyed polyester comprising 0.08 to 3.00% by weight of a carbon black, as an island component; preparing a nonwoven fabric by needle punching with the staple fiber; Impregnating a polymer elastomer comprising 1 to 6% by weight of a carbon black in the nonwoven fabric; forming napping by eluting a sea component of the sea-island type composite fiber from the nonwoven fabric to produce ultrafine fiber and grinding surface of the nonwoven fabric; and dyeing nonwoven fabric using a dispersion dye.

Description

EXAMPLE 1

[0041] 1) Production of Sea-Island Type Staple Fiber

[0042] Polyethylene terephthalate was prepared as an island component and an alkali soluble copolymer polyester was prepared as a sea component and the island component and the sea component were introduced into respective extruders to melt and extrude the when the island component was melt and extruded, carbon black master batch was side-fed to the island component and discharged through a spinning nozzle to prepare a sea-island type filament having a carbon black of 1.5% by weight in the island component of black polyethylene terephthalate.

[0043] Then, the sea-island type filament was stretched, crimped so that the crimp number became 10 finch, fixed by heating and then cut into 51 mm to prepare a sea-island type staple fiber.

[0044] 2) Production of Nonwoven Fabric

[0045] A multi-layered web was formed through the carding and the crosslapping of the sea-island type staple fiber followed by needle punching to prepare a nonwoven fabric.

[0046] 3) Production of Nonwoven Fabric in which Elastomer is Impregnated

[0047] The nonwoven fabric was immersed in an impregnation solution containing polyurethane and carbon black, the polyurethane was coagulated in an aqueous solution of dimethylformamide, washed with water to prepare a black polyurethane-impregnated nonwoven fabric in which 30% by weight of a polyurethane elastomer containing 5% by weight of carbon black is impregnated.

[0048] 4) Production of Artificial Leather

[0049] A sea component was eluted by treating the nonwoven fabric in which the black polyurethane was impregnated, with a caustic soda aqueous solution having a concentration of 5% by weight. By the above, a nonwoven fabric of black polyethylene terephthalate fibers having a number of fibers divided per filament of 16 and a single yarn fineness of 0.15 denier was prepared.

[0050] The surface of the nonwoven was ground with sandpaper having a roughness of #150 to form the napped, and then was dyed under the following dyeing conditions.

[0051] <Dyeing Condition>

[0052] A) Dye:

[0053] Black dispersion dye (anthraquinone-based) 0.8% o.w.f. (on the weight of fiber)

[0054] Red dispersion dye (anthraquinone-based) 0.5% o.w.f.

[0055] Blue dispersion dye (anthraquinone-based) 1.5% o.w.f.

[0056] Yellow dispersion dye (anthraquinone-based) 0.5% o.w.f.

[0057] B) UV-absorber: triazine derivative 4.0% o.w.f.

[0058] C) Dispersant: nonionic fatty acid ester 1 g/L

[0059] D) Acid: acetic acid 1 g/L

[0060] E) Bath ratio (additive weight: solvent weight): 1:20

[0061] F) Dyeing temperature and time: 125 C., 50 min

[0062] After completion of the dyeing, the dyeing residue was discharged from the dyeing machine and water was again added to the dyeing machine and then reduction cleaned under reduction cleaning condition (sodium hypochlorite: 8 g/L, sodium hydroxide 4 g/L, bath ratio 1:20) and dried to prepare an artificial leather having a deep black color.

Examples 2 and 3

[0063] These Examples were performed in the same manner as the Example 1, except that the content of carbon black in the island component of the sea-island type filament, the content of carbon black in the polyurethane, and the dye amount in dyeing were as shown in Table 1. Artificial leather having black or dark gray with medium shades was prepared in the Example 2 and artificial leather having pale gray was prepared in Example 3.

Comparative Examples 1 to 6

[0064] The artificial leathers were prepared by performing the same manner as the Example 1, except that the content of carbon black in the island component of the sea-island type filament, the content of carbon black in the polyurethane, and the dye amount in dyeing were as shown in Table 1.

TABLE-US-00001 TABLE 1 Content of carbon black Content of Black Red Blue Yellow in island carbon black dispersion dispersion dispersion dispersion component in polyurethane dye dye dye dye (wt %) (wt %) (% o.w.f.) (% o.w.f.) (% o.w.f.) (% o.w.f.) Example 1 1.5 5 0.8 0.5 1.5 0.5 Comparative 0 5 10.55 2.49 5.17 10.51 Example 1 Comparative 0 1 11.02 2.41 5.23 10.8 Example 2 Comparative 0 0 11.5 2.3 5.3 11 Example 3 Example 2 0.45 1 0 0.8 0 5 Comparative 0 1 1.45 1.06 0 7.06 Example 4 Comparative 0 0 2.2 1.15 0 7.5 Example 5 Example 3 0.1 1 0 0.1 0.12 0.12 Comparative 0 0 0 1.55 1.47 1.22 Example 6

[0065] Table 2 shows the colorimetric values measured using CCM for the dyed materials in the above Examples and Comparative Examples.

TABLE-US-00002 TABLE 2 L a b DE Example 1 20.19 0.18 0.05 Comparative 20.66 0.04 0.24 0.53 Example 1 Comparative 19.97 0.34 0.12 0.32 Example 2 Comparative 20.42 0.18 0.12 0.43 Example 3 Example 2 36.12 9.58 13.01 Comparative 36.56 9.32 13.26 0.57 Example 4 Comparative 35.84 9.36 12.88 0.38 Example 5 Example 3 52.14 0.73 3.6 Comparative 52.6 0.61 3.79 0.51 Example 6

[0066] From the above Tables 1 and 2, it is confirmed that the amounts of the dyes used for the same color density in Examples was smaller than that in Comparative Examples.

[0067] Evaluation results using the following evaluation methods for the above Examples and Comparative Examples are shown in Table 3 below.

[0068] <Evaluation Method>

[0069] 1. Fastness to Light

[0070] The artificial leather prepared in the above Examples and Comparative Examples was irradiated with a light quantity of 338.6 KJ/m.sup.2 according to the method specified in the ISO 105-B06: 1998 condition 5, and the grade of fastness to light was determined using the gray scale (ISO 105 A02).

[0071] 2. Fastness to Rubbing

[0072] The Fastness to rubbing was measured according to ISO 105 X12 method.

[0073] In the evaluation of the fastness to dry rubbing, two specimens of 50 mm width and 130 mm length parallel to the longitudinal direction are fixed to the test stand of the rubbing tester and the rubbers of the test rollers are covered with white cotton cloth of 50 mm length and 50 mm length and fixed. After applying a load of 90.2 N to the rubber, the surface of the specimen was reciprocated 10 times at a reciprocating speed of 10 times/min and the passing distance of 100 mm. The white cotton cloth was peeled off and the contamination degree of the white cotton cloth was judged according to gray scale.

[0074] The fastness to wet rubbing is evaluation in the same manner as the fastness to dry rubbing and the water is picked up at 98 to 100% in the white cotton cloth.

[0075] 3. Dye Amount (Unit: Times)

[0076] It is calculated by dividing total used amount of dye in the Comparative Example (% O.w.f.) by total used amount of dye in the Example (% o.w.f.).

[0077] 4. Surface Color Uniformity

[0078] If artificial leather does not show coloration of polyurethane to exhibit dichroism, it marks as bad and if not, it marks as good.

[0079] <Evaluation Result>

TABLE-US-00003 TABLE 3 Fastness Fastness Fastness to dry to wet Dye Surface to light rubbing rubbing amount* color (grade) (grade) (grade) (times) uniformity Example 1 4 4~5 4 Good Comparative 2~3 4 3~4 8.7 Good Example 1 Comparative 2~3 4 3~4 8.9 Bad Example 2 Comparative 2~3 4 3~4 9.1 Bad Example 3 Example 2 3 4~5 4 Good Comparative 2 4 4 1.7 Good Example 4 Comparative 2 4 4 2.2 Bad Example 5 Example 3 4 4~5 4~5 Good Comparative 3 4~5 4~5 12.5 Good Example 6 *The respective amount of dye used in Comparative Examples 1, 2 and 3 is a multiple of Example 1 and those in Comparative Examples 4, 5 is a multiple of Example 2, and that in Comparative Example 6 is a multiple of Example 3.

[0080] From Table 3, when both the ultrafine fibers composed of the artificial leather and the polyurethane contain carbon black (Examples 1, 2 and 3), the fastness to light, the fastness to dry rubbing and the fastness to wet rubbing thereof is confirmed to be excellent as grade 4 or higher and the surface color uniformity is also excellent.

[0081] Further, in the case of ultrafine yarn without carbon black (Comparative Examples 1 to 6), the fastness to light was remarkably lowered, and in particular, when the carbon black was not present in either of the ultrafine yarn and the polyurethane, it can be confirmed that the used amount of dye increases for showing the same color.

INDUSTRIAL APPLICABILITY

[0082] As described above, the present invention can solve problems such as ununiform dyeing and difficulty in uniform and clear development of color with a deep shade in nonwoven artificial leather for fashion goods such as suede type furniture skin material, inner skin and outer skin of bags, It is possible to improve the cost saving and the fastness property by improving the problem of excess dye to be added for color development with medium or deep shade.