Napped artificial leather dyed with cationic dye, and method for manufacturing the same

Abstract

Disclosed is a napped artificial leather dyed with a cationic dye, including: a non-woven fabric of a cationic dyeable polyester fiber having a fineness of 0.07 to 0.9 dtex; and an elastic polymer provided inside the non-woven fabric, wherein the napped artificial leather has L* value≤50, a grade of color difference determined in an evaluation of color migration to PVC under a load 0.75 kg/cm at 50° C. for 16 hours, of 4 or more, a tear strength per mm of thickness of 30 N or more, and a peel strength of 3 kg/cm or more.

Claims

1. A napped artificial leather dyed with a cationic dye, comprising: a non-woven fabric of cationic dyeable polyester fibers having a fineness of 0.07 to 0.9 dtex; and an elastic polymer provided inside the non-woven fabric, wherein the cationic dyeable polyester fibers include a polyester containing a dicarboxylic acid unit mainly of a terephthalic acid unit and a glycol unit mainly of an ethylene glycol unit, and as a second dicarboxylic acid unit, 1.5 to 3 mol % of a unit represented by formula (I.sub.a): ##STR00005## and wherein the napped artificial leather has L* value≤50, a chlorine content of 90 ppm or less, a grade of color difference, determined in an evaluation of color migration to PVC under a load of 0.75 kg/cm at 50° C. for 16 hours, of 4 or more, a tear strength per mm of thickness of 30 N or more, and a peel strength of 3 kg/cm or more, wherein the tear strength is measured according to a method, wherein a test strip of 10 cm long by 4 cm wide is cut out from the napped artificial leather, then, a 5 cm-long cut is made at a center of a shorter side of the test strip, parallel to a longer side, then, using a tensile testing machine, a first and a second end opposite the first end of the test strip are nipped by a first and second chuck of a jig of the testing machine, and a stress-strain (s-s) curve is measured at a tensile speed of 10 cm/min.

2. The napped artificial leather according to claim 1, wherein the napped artificial leather has a Martindale abrasion loss (12 KPa) of 100 mg or less after 35000 times of rubbing.

3. The napped artificial leather according to claim 1, wherein the cationic dyeable polyester fibers are filaments.

4. The napped artificial leather according to claim 1, wherein the cationic dyeable polyester fibers have a glass transition temperature (Tg) in a range of 60 to 70° C.

5. The napped artificial leather dyed with a cationic dye according to claim 1, obtained by a process comprising: dyeing, with a cationic dye, a napped artificial leather base material including a non-woven fabric of ultrafine fibers of 0.07 to 0.9 dtex of a cationic dyeable polyester and an elastic polymer provided inside the non-woven fabric, and having a napped surface at least on one surface thereof, wherein the cationic dyeable polyester contains a dicarboxylic acid unit containing mainly a terephthalic acid unit and 1.5 to 3 mol % of a unit represented by formula (I.sub.b): ##STR00006## where X represents a quaternary phosphonium ion or a quaternary ammonium ion], and a glycol unit containing mainly an ethylene glycol unit, and the napped artificial leather has been subjected to a washing treatment in a hot water bath containing an anionic surfactant after being dyed with the cationic dye, and/or has a chlorine content of 90 ppm or less.

6. The napped artificial leather according to claim 5, wherein the cationic dyeable polyester contains greater than 0 to 0.2 mol % of a sulfoiosphthalic acid alkali metal salt unit.

7. The napped artificial leather according to claim 5, wherein the cationic dyeable polyester has a glass transition temperature (Tg) of 60 to 70° C.

8. A method for manufacturing the napped artificial leather dyed with a cationic dye according to claim 1, the method comprising: preparing an artificial leather base material including a non-woven fabric of ultrafine fibers of 0.07 to 0.9 dtex of a cationic dyeable polyester and an elastic polymer impregnated into the non-woven fabric; dyeing the artificial leather base material using a cationic dye, and thereafter washing the artificial leather base material in a hot water bath at 50 to 100° C. containing an anionic surfactant; and, either before or after the dyeing and washing, napping at least one surface of the artificial leather base material, wherein the cationic dyeable polyester includes a polyester containing a dicarboxylic acid unit mainly of a terephthalic acid unit and a glycol unit mainly of an ethylene glycol unit, and as a second dicarboxylic acid unit, 1.5 to 3 mol % of a unit represented by formula (I.sub.b): ##STR00007## where X represents a quaternary phosphonium ion or a quaternary ammonium ion.

9. The method according to claim 8, wherein the cationic dyeable polyester contains greater than 0 to 0.2 mol % of a sulfoiosphthalic acid alkali metal salt unit.

10. The method according to claim 8, wherein the cationic dyeable polyester contains, a 1,4-cyclohexanedicarboxylic acid unit and an adipic acid unit each in a range of 1 to 6 mol %.

11. The method according to claim 8, wherein the cationic dyeable polyester contains an isophthalic acid unit in a range of 1 to 6 mol %.

12. The method according to claim 8, wherein the washing of the artificial leather base material in a hot water bath at 50 to 100° C. containing an anionic surfactant is performed to such an extent that a chlorine content is 90 ppm or less.

13. The method according to claim 8, wherein the preparing includes: forming an ultrafine fiber-generating fiber entangled body including ultrafine fiber-generating fibers capable of forming the ultrafine fibers; converting the ultrafine fiber-generating fibers into the ultrafine fibers to form a non-woven fabric of the ultrafine fibers; and impregnating an elastic polymer into the ultrafine fiber-generating fiber entangled body or the non-woven fabric of the ultrafine fibers.

14. The method according to claim 13, wherein the ultrafine fiber-generating fibers are filaments.

15. The method according to claim 13, wherein, in the forming of the ultrafine fiber-generating fiber entangled body, the ultrafine fiber-generating fibers are entangled to such an extent that a napped artificial leather having a tear strength per mm of thickness of 30 N or more and a peel strength of 3 kg/cm or more is obtained.

Description

EXAMPLES

(1) Hereinafter, the present invention will be described more specifically by way of examples. It should be appreciated that the scope of the present invention is by no means limited by the examples.

Example 1

(2) Ethylene-modified polyvinyl alcohol (ethylene unit content: 8.5 mol %, a degree of polymerization: 380, a saponification degree: 98.7 mol %) as a thermoplastic resin serving as a sea component, and a polyethylene terephthalate (PET) (containing 1.7 mol % of a sulfoisophthalic acid tetrabutyl phosphonium salt unit, 5 mol % of a 1,4-cyclohexanedicarboxylic acid unit, and 5 mol % of an adipic acid unit and having a glass transition temperature of 62° C.) modified with a sulfoisophthalic acid tetrabutyl phosphonium salt as a thermoplastic resin serving as an island component were molten separately. Then, each of the molten resins was supplied to a multicomponent fiber spinning spinneret having many nozzle holes disposed in parallel, such that a cross section on which 25 island component portions having uniform cross-sectional areas were distributed in the sea component can be formed. At this time, the molten resins were supplied while adjusting the pressure such that the mass ratio between the sea component and the island component satisfies Sea component/Island component=25/75. Then, the molten resins were discharged from the nozzle holes set at a spinneret temperature of 260° C.

(3) Then, the molten fibers discharged from the nozzle holes were drawn by suction by using an air jet nozzle suction apparatus with an air stream pressure regulated so as to provide an average spinning speed of 3700 m/min, thus spinning the island-in-the-sea composite filaments with a fineness of 2.1 dtex at a high speed. The spun island-in-the-sea composite filaments were continuously piled on a movable net while being suctioned from the back side of the net. The piled amount was regulated by regulating the movement speed of the net. Then, in order to suppress the fuzzing on the surface, the island-in-the-sea composite filaments piled on the net were softly pressed with a metal roll at 42° C. Then, the island-in-the-sea composite filaments were removed from the net, and allowed to pass between a grid-patterned metal roll having a surface temperature of 75° C. and a back roll, thereby hot pressing the fibers with a linear load of 200 N/mm. In this manner, a filament web having a basis weight of 34 g/m.sup.2 and in which the fibers on the surface were temporarily fused in a grid pattern was obtained.

(4) Next, an oil solution mixed with an antistatic agent was sprayed to the surface of the obtained filament web, and thereafter, 10 sheets of the filament web were stacked by using a cross lapper apparatus to form a superposed web with a total basis weight of 340 g/m.sup.2, and an oil solution for preventing the needle from breaking was further sprayed thereto. Then, the superposed web was needle-punched, thereby performing a three-dimensional entangling treatment. Specifically, the stack was needle-punched at a density of 3300 punch/cm.sup.2 alternately from both sides by using 6-barb needles with a distance of 3.2 mm from the needle tip to the first barb at a punching depth of 8.3 mm. The area shrinkage by the needle punching was 18%, and the basis weight of the entangled web after the needle punching was 415 g/m.sup.2.

(5) The obtained entangled web was densified by being subjected to a heat-moisture shrinking treatment in the following manner. Specifically, water at 18° C. was uniformly sprayed in an amount of 10 mass % to the entangled web, and the entangled web was heat-treated by being stood still in an atmosphere with a temperature of 70° C. and a relative humidity of 95% for 3 minutes with no tension applied, thereby heat-moist shrinking the entangled web so as to increase the apparent fiber density. The area shrinkage by the heat-moisture shrinking treatment was 45%, and the densified entangled web had a basis weight of 750 g/m.sup.2 and an apparent density of 0.52 g/cm.sup.3. Then, for further densification, the entangled web was pressed with a dry-heat roll, thereby adjusting the apparent density to 0.60 g/cm.sup.3.

(6) Next, an emulsion of an aqueous polyurethane capable of forming a cross-linked structure after being solidified (emulsion having a polyurethane solid content concentration of 30% and composed mainly of polycarbonate/ether polyurethane) was impregnated into the densified entangled web as a polyurethane elastomer. Then, the entangled web was dried in a drying furnace at 150° C.

(7) Next, the entangled web in which the aqueous polyurethane has been applied was immersed in hot water at 95° C. for 20 minutes to remove the sea component contained in the island-in-the-sea composite filaments by extraction, and then was dried in a drying furnace at 120° C., thereby obtaining an artificial leather base material containing a non-woven fabric of ultrafine filaments having a fineness of 0.1 dtex and into which the aqueous polyurethane was impregnated. The mass ratio of the non-woven fabric to the aqueous polyurethane of the obtained artificial leather base material was 90/10. Then, the obtained artificial leather base material was sliced into halves in the thickness direction, and the surface thereof was napped by being buffed with sand paper with a grit number of 600.

(8) Then, the napped artificial leather was dyed into a red color by being immersed for 40 minutes in a dyeing bath at 90° C. containing 8% owf of a cationic dye “Nichilon Red-GL” (manufactured by NISSEI KASEI CO., LTD.; containing 4% of washable chlorine in the dye) as a dye and 1 g/L of 90% acetic acid as a dyeing auxiliary at a liquor ratio of 1:30. Then, a step of washing the napped artificial leather using a hot water bath containing 2 g/L of Soluzine R as an anionic surfactant at 70° C. for 20 minutes was repeated twice in the same dyeing bath. Then, after washing, the napped artificial leather was dried to give a dyed napped artificial leather.

(9) In this manner, a dyed napped artificial leather including a non-woven fabric of ultrafine filaments with a fineness of 0.1 dtex and having a napped surface on one surface was obtained. The obtained napped artificial leather had a thickness of 0.6 mm and a basis weight of 350 g/m.sup.2. The length of the napped fibers was about 80 μm.

(10) Then, the napped artificial leather was evaluated for the spinning stability, the color development, the color migration, and the tear strength of the island-in-the-sea composite filaments in the following manner.

(11) [Spinning Stability]

(12) The stability during suction and drawing using an air jet nozzle suction apparatus with an air stream pressure regulated so as to provide an average spinning speed of 3700 m/min as described above was evaluated according to the following criteria.

(13) A: There was no fiber breakage.

(14) B: Many defects resulting from fiber breakage were contained, or fiber breakage made spinning impossible.

(15) [Color Development]

(16) Using a spectrophotometer (CM-3700 manufactured by KONICA MINOLTA HOLDINGS, INC.), the lightness L* was determined on the basis of coordinate values of the L*a*b* color system of the surface of the cut-out dyed napped artificial leather in accordance with JIS Z 8729. This value was an average of three values measured at average positions evenly selected from the test strip.

(17) [Color Migration]

(18) A 0.8 mm-thick vinyl chloride film (white) was placed on the surface of the cut-out napped artificial leather, and a pressure was uniformly applied thereto so as to provide a load of 750 g/cm.sup.2. Then, the napped artificial leather was left under an atmosphere of 50° C. and a relative humidity of 15% for 16 hours. Then, the color difference ΔE* between the vinyl chloride film before undergoing color migration and the vinyl chloride film after undergoing color migration was measured using a spectrophotometer, and evaluated according to the following criteria.

(19) Grade 5: 0.0≤ΔE*≤0.2

(20) Grade 4-5: 0.2<ΔE*≤1.4

(21) Grade 4: 1.4<ΔE*≤2.0

(22) Grade 3-4: 2.0<ΔE*≤3.0

(23) Grade 3: 3.0<ΔE*<3.8

(24) Grade 2-3: 3.8<ΔE*≤5.8

(25) Grade 2: 5.8<ΔE*≤7.8

(26) Grade 1-2: 7.8<ΔE*≤11.4

(27) Grade 1: 11.4<ΔE*

(28) [Tear Strength]

(29) A test strip of 10 cm long by 4 cm wide was cut out from the obtained dyed napped artificial leather. Then, a 5 cm-long cut was made at the center of the shorter side of the test strip, parallel to the longer side. Then, using a tensile testing machine, the split ends of the test strip were nipped by chucks of the jig, and an s-s curve was measured at a tensile speed of 10 cm/min. A value obtained by dividing the maximum load by a predetermined basis weight of the test strip was used as a tear strength per mm of thickness. This value is an average value of three test strips.

(30) [Peel Strength]

(31) Two test strips of 15 cm long by 2.5 cm wide were cut out from the obtained dyed napped artificial leather. Then, the two test strips were superposed with each other with a 100-μm polyurethane film (NASA-600, 10 cm long by 2.5 cm wide) interposed therebetween, to give a superposed body. Note that the polyurethane film is not superposed on a portion 2.5 cm from either end of each test strip. Then, using a plate hot pressing machine, the superposed body was bonded by being pressed for 60 seconds under the conditions of a temperature of 130° C. and a surface pressure of 5 kg/cm.sup.2, to form an evaluation sample. Using a tensile testing machine at room temperature, the unbonded 2.5 cm portions of the obtained evaluation sample were held by the upper and lower chucks, respectively, and an s-s curve was measured at a tensile speed of 10 cm/min. Taking a median value of the portion where the s-s curve is substantially constant as an average value, a value obtained by dividing the average value by the sample width 2.5 cm was used as a peel strength. This value is an average value of three test strips.

(32) [Martindale Abrasion Loss]

(33) A Martindale abrasion loss in accordance with JIS L 1096 was measured. Specifically, a circular test strip having a diameter of 38 mm was cut out from the obtained dyed napped artificial leather. Then, the test strip was left in a standard state (20° C.×65% RH) for 24 hours, and a weight W.sub.1 (mg) was measured. Then, a standard abrading cloth and the above-described test strip were set on a Martindale abrasion tester, and their surfaces were rubbed each other with a load of 12 KPa applied until the counter reached 35000. Then, a weight W.sub.2 (mg) of the test strip after completion of the test was measured, and an abrasion loss W (mg)(W.sub.1-W.sub.2), which was a weight loss of the test strip, was calculated.

(34) [Chlorine Content]

(35) In accordance with the method BS EN 14582: 2007, the chlorine content for the dyed napped artificial leather was measured by quantification.

(36) [Glass Transition Temperature and Melting Point]

(37) The glass transition temperature and the melting point of the polyester were measured using a differential scanning calorimeter (DSC) (TA-3000 manufactured by Mettler-Toledo International Inc.).

(38) The results are shown in Table 1 below.

(39) TABLE-US-00001 TABLE 1 Polyester Glass Copolymer Other transition Poly- unit modifications temper- Melting urethane Example Fineness (*1) (*2) ature point ratio Anionic No. (dtex) (mol %) (mol %) (° C.) (° C.) (%) Dye surfactant  1 0.1 A 1.7 X + Y 10 62 228 10 Cationic Present  2 0.1 A 2.5 X + Y 10 61 226 10 Cationic Present  3 0.1 A 3 X + Y 10 61 225 10 Cationic Present  4 0.1 A 1.7 Z 3 70 241 10 Cationic Present  5 0.1 A 1.7 Z 6 67 234 10 Cationic Present  6 0.1 A 1.7 X + Y 10 62 228 20 Cationic Present  7 0.1 A 1.7 X + Y 10 62 228 25 Cationic Present  8 0.1 B 1.7 X + Y 10 62 228 10 Cationic Present  9 0.2 A 1.7 Z 3 70 241 10 Cationic Present 10 0.3 A 1.7 Z 3 70 241 10 Cationic Present 11 0.1 A 1.7 — — 76 249 10 Cationic Present 12 0.1 A 2.5 — — 75 248 10 Cationic Present Com. Ex. 1 0.1 A 4 X + Y 10 59 223 10 Cationic Present Com. Ex. 2 0.1 C 1.7 X + Y 10 62 228 10 Cationic Present Com. Ex. 3 0.1 A 1.7 X + Y 10 62 230 10 Cationic Absent Com. Ex. 4 0.1 — — Z 6 73 241 10 Disperse Present Ref. Ex. 1 0.1 A 1.7 X + Y 10 62 228 10 Cationic Present Evaluation results Color Color Chlorine Peel Tear develop- migration Abrasion Example content strength strength Spinning ment (grade) loss No. [ppm] (Kg/cm) (N/mm) Stability (L* value) (ΔE*) (mg)  1 59 3.8 45 A 45 4-5 1.0 95  2 53 3.5 39 A 45 4-5 1.0 95  3 51 3.2 34 A 45 4-5 0.8 98  4 65 4.0 55 A 45 4-5 0.8 83  5 67 3.9 49 A 45 4-5 1.0 85  6 70 4.0 45 A 45 4 1.5 80  7 77 4.2 43 A 45 4 1.8 76  8 59 3.8 43 A 45 4-5 1.0 93  9 75 4.5 55 A 40 4-5 0.8 58 10 75 4.2 53 A 38 4-5 0.4 62 11 71 4.8 58 B 45 4-5 0.7 55 12 68 3.9 49 B 45 4-5 0.5 98 Com. Ex. 1 58 2.5 29 A 45 4-5 0.7 120 Com. Ex. 2 78 2.3 24 B 45 4-5 1.0 189 Com. Ex. 3 153 3.8 45 A 45 2-3 4.2 95 Com. Ex. 4 — 5.9 61 A 46 2 6.0 52 Ref. Ex. 1 63 2.5 57 A 45 4-5 1.0 108 *1 A: Sulfoisophthalic acid tetrabutyl phosphonium salt B: Sulfoisophthalic acid tetrabutyl ammonium salt C: Sulfoisophthalic acid sodium salt *2 X: Cyclohexanedicarboxylic acid Y: Adipic acid Z: Isophthalic acid

Example 2

(40) A dyed napped artificial leather was obtained in the same manner as in Example 1 except that a PET (containing 2.5 mol % of a sulfoisophthalic acid tetrabutyl phosphonium salt unit, 5 mol % of a 1,4-cyclohexanedicarboxylic acid unit, and 5 mol % of an adipic acid unit) modified with a sulfoisophthalic acid tetrabutyl phosphonium salt was used as a thermoplastic resin serving as an island component. Then, the obtained napped artificial leather was evaluated in the same manner as in Example 1. The results are shown in Table 1.

Example 3

(41) A dyed napped artificial leather was obtained in the same manner as in Example 1 except that a PET (containing 3 mol % of a sulfoisophthalic acid tetrabutyl phosphonium salt unit, 5 mol % of a 1,4-cyclohexanedicarboxylic acid unit, and 5 mol % of an adipic acid unit) modified with a sulfoisophthalic acid tetrabutyl phosphonium salt was used as a thermoplastic resin serving as an island component. Then, the obtained napped artificial leather was evaluated in the same manner as in Example 1. The results are shown in Table 1.

Example 4

(42) A dyed napped artificial leather was obtained in the same manner as in Example 1 except that a PET (containing 1.7 mol % of a sulfoisophthalic acid tetrabutyl phosphonium salt unit and 3 mol % of an isophthalic acid unit) modified with a sulfoisophthalic acid tetrabutyl phosphonium salt was used as a thermoplastic resin serving as an island component. Then, the obtained napped artificial leather was evaluated in the same manner as in Example 1. The results are shown in Table 1.

Example 5

(43) A dyed napped artificial leather was obtained in the same manner as in Example 1 except that a PET (containing 1.7 mol % of a sulfoisophthalic acid tetrabutyl phosphonium salt unit and 6 mol % of an isophthalic acid unit) modified with a sulfoisophthalic acid tetrabutyl phosphonium salt was used as a thermoplastic resin serving as an island component. Then, the obtained napped artificial leather was evaluated in the same manner as in Example 1. The results are shown in Table 1.

Example 6

(44) A dyed napped artificial leather was obtained in the same manner as in Example 1 except that the mass ratio of the non-woven fabric to the aqueous polyurethane of the obtained artificial leather base material was changed to 80/20. Then, the obtained napped artificial leather was evaluated in the same manner as in Example 1. The results are shown in Table 1.

Example 7

(45) A dyed napped artificial leather was obtained in the same manner as in Example 1 except that the mass ratio of the non-woven fabric to the aqueous polyurethane of the obtained artificial leather base material was changed to 75/25. Then, the obtained napped artificial leather was evaluated in the same manner as in Example 1. The results are shown in Table 1.

Example 8

(46) A dyed napped artificial leather was obtained in the same manner as in Example 1 except that a PET (containing 1.7 mol % of a sulfoisophthalic acid tetrabutyl ammonium salt unit, 5 mol % of 1,4-cyclohexanedicarboxylic acid, and 5 mol % of adipic acid) modified with a sulfoisophthalic acid tetrabutyl ammonium salt was used as a thermoplastic resin serving as an island component. Then, the obtained napped artificial leather was evaluated in the same manner as in Example 1. The results are shown in Table 1.

Example 9

(47) A dyed napped artificial leather was obtained in the same manner as in Example 1 except that the same thermoplastic resin serving as an island component as that used in Example 4 was used, and a multicomponent fiber spinning spinneret that could form a cross section on which 12 island component portions having uniform cross-sectional areas are distributed in the sea component was used.

Example 10

(48) A dyed napped artificial leather was obtained in the same manner as in Example 1 except that the same thermoplastic resin serving as an island component as that used in Example 4 was used, a multicomponent fiber spinning spinneret that could form a cross section on which 12 island component portions having uniform cross-sectional areas are distributed in the sea component was used, and island-in-the-sea composite filaments having a fineness of 3.3 dtex were spun at a high speed.

Example 11

(49) A dyed napped artificial leather was obtained in the same manner as in Example 1 except that a PET (containing 1.7 mold of a sulfoisophthalic acid tetrabutyl phosphonium salt unit) modified only with a sulfoisophthalic acid tetrabutyl phosphonium salt was used as a thermoplastic resin serving as an island component. Then, the obtained napped artificial leather was evaluated in the same manner as in Example 1. The results are shown in Table 1.

Example 12

(50) A dyed napped artificial leather was obtained in the same manner as in Example 1 except that a PET (containing 2.5 mol % of a sulfoisophthalic acid tetrabutyl phosphonium salt unit) modified only with a sulfoisophthalic acid tetrabutyl phosphonium salt was used as a thermoplastic resin serving as an island component. Then, the obtained napped artificial leather was evaluated in the same manner as in Example 1. The results are shown in Table 1.

Comparative Example 1

(51) A dyed napped artificial leather was obtained in the same manner as in Example 1 except that a PET (containing 4 mol % of a sulfoisophthalic acid tetrabutyl phosphonium salt unit, 5 mol % of a 1,4-cyclohexanedicarboxylic acid unit, and 5 mol % of an adipic acid unit) modified with a sulfoisophthalic acid tetrabutyl phosphonium salt was used as a thermoplastic resin serving as an island component. Then, the obtained napped artificial leather was evaluated in the same manner as in Example 1. The results are shown in Table 1.

Comparative Example 2

(52) Island-in-the-sea composite filaments were spun in the same manner as in Example 1 except that a PET (containing 1.7 mol % of a sulfoisophthalic acid sodium salt unit, 5 mol % of a 1,4-cyclohexanedicarboxylic acid unit, and 5 mol % of an adipic acid unit) modified with a sulfoisophthalic acid sodium salt was used as a thermoplastic resin serving as an island component. However, the fibers were broken by the tension applied when the molten polymer discharged from the spinning nozzle was suctioned by the air jet nozzle with an air stream pressure regulated so as to provide an average spinning rate of 3700 m/min, while being cooled, so that melt-spinning was not performed in a stable manner. Accordingly, melt-spinning was performed at a low speed by reducing the pressure of the suction air. The subsequent steps were performed in the same manner as in Example 1, to obtain a dyed napped artificial leather. Then, the obtained napped artificial leather was evaluated in the same manner as in Example 1. The results are shown in Table 1.

Comparative Example 3

(53) A napped artificial leather obtained in the same manner as in Example 1 was dyed into a red color by being immersed for 40 minutes in a dyeing bath at 90° C. containing 8% owf of a cationic dye “Nichilon Red-GL” (manufactured by NISSEI KASEI CO., LTD.; containing 4% of washable chlorine in the dye) as a dye and 1 g/L of 90% acetic acid as a dyeing aid at a liquor ratio of 1:30. Then, a step of washing the napped artificial leather using a hot water bath free of an anionic surfactant at 70° C. for 20 minutes was repeated twice in the same dyeing bath. Then, after washing, the napped artificial leather was dried, to obtain a dyed napped artificial leather.

Comparative Example 4

(54) A napped artificial leather was obtained in the same manner as in Example 1 except that an isophthalic acid-modified PET (containing 6 mol % of an isophthalic acid unit) was used as a thermoplastic resin serving as an island component. Then, using Disperse Red-W, Kiwalon Rubine 2GW, and Kiwalon Yellow 6GF serving as a disperse dye, the napped artificial leather was jet-dyed for one hour at 130° C., and was subjected to reduction cleaning in the same dyeing bath, to obtain a dyed napped artificial leather. Then, the obtained napped artificial leather was evaluated in the same manner as in Example 1. The results are shown in Table 1.

Reference Example 1

(55) A dyed napped artificial leather was obtained in the same manner as in Examples 1 except that the filament web was entangled under the following conditions in Example 1.

(56) An oil solution mixed with an antistatic agent was sprayed to the surface of the obtained filament web, and thereafter, 10 sheets of the filament web were stacked by using a cross lapper apparatus to form a superposed web with a total basis weight of 340 g/m.sup.2, and an oil solution for preventing the needle from breaking was further sprayed thereto. Then, the superposed web was needle-punched, thereby performing a three-dimensional entangling treatment. Specifically, the stack was needle-punched at a density of 2400 punch/cm.sup.2 alternately from both sides by using 6-barb needles with a distance of 3.2 mm from the needle tip to the first barb at a punching depth of 8.3 mm. The area shrinkage by the needle punching was 18%, and the basis weight of the entangled web after the needle punching was 415 g/m.sup.2.

(57) Then, the obtained napped artificial leather was evaluated in the same manner as in Example 1. The results are shown in Table 1.

(58) Referring to Table 1, all of the napped artificial leathers of Examples 1 to 12 according to the present invention had a tear strength per mm of thickness of 30 N or more and a peel strength of 3 kg/cm or more. Accordingly, all of the napped artificial leathers had a Martindale abrasion loss of 100 mg or less after 35000 times of rubbing. Furthermore, they also had a chlorine content of 90 ppm or less, and the results of the color migration evaluation were a grade 4 or more. Note that while Examples 1 to 10 exhibited excellent high-speed spinning stability during manufacture, Examples 11 and 12 exhibited inferior high-speed spinning stability

(59) On the other hand, the napped artificial leather of Comparative example 1, in which ultrafine fibers of a polyester containing 4 mol % of a unit represented by the formula (II), had a low tear strength and a low peel strength. Accordingly, it had a large Martindale abrasion loss. The napped artificial leather of Comparative example 2, in which ultrafine fibers of a polyester containing 1.7 mol % of a sulfoisophthalic acid sodium salt, also had a low tear strength and a low peel strength, and thus had a large Martindale abrasion loss. It also exhibited poor high-speed spinning stability during manufacture. The napped artificial leather of Comparative example 3, which was washed in a hot water bath free of an anionic surfactant during washing after dyeing with cation, had a high chlorine content, and was very poor in terms of the color migration. The napped artificial leather of Comparative example 4, which was dyed with a disperse dye, was also poor in terms of the color migration. In addition, although Reference example 1 exhibited excellent high-speed spinning stability during manufacture, it had a low tear strength and a low peel strength owing to a low entangled state, and thus had a large Martindale abrasion loss.

INDUSTRIAL APPLICABILITY

(60) A napped artificial leather obtained by the present invention can be preferably used as a skin material for clothing, shoes, articles of furniture, car seats, general merchandise, and the like.