Polyamide sea-island fiber, preparation method therefor, and use thereof

Abstract

The present invention relates to the technical field of polyamide materials, and specifically relates to a polyamide sea-island fiber and a process for producing the same and the use thereof. In the polyamide sea-island fiber, the island component is a polyamide resin selected from one of polyamide 56, polyamide 510, polyamide 511, polyamide 512, polyamide 513, polyamide 514, polyamide 515 and polyamide 516, preferably polyamide 56 or polyamide 510; the sea component is one of polyethylene, low-density polyethylene, polystyrene, water-soluble polyesters, polyesters and polyurethanes, preferably polyethylene, low-density polyethylene or water-soluble polyester. The polyamide sea-island fiber of the present invention has better mechanical properties, better softness, good dyeing properties, high grade of dyeing grey scale, high dye uptake, high dyeing depth and high color fastness.

What is claimed is: 
     
         1 . A polyamide sea-island fiber, characterized in that an island component is a polyamide resin selected from one of polyamide 56, polyamide 510, polyamide 511, polyamide 512, polyamide 513, polyamide 514, polyamide 515 and polyamide 516, preferably polyamide 56 or polyamide 510; a sea component is one of polyethylene, low-density polyethylene, polystyrene, water-soluble polyesters, polyesters and polyurethanes, preferably polyethylene, low-density polyethylene or water-soluble polyesters. 
     
     
         2 . The polyamide sea-island fiber according to  claim 1 , characterized in that the island component is selected from the group consisting of super bright polyamide resins, semi dull polyamide resins, full dull polyamide resins and mixtures thereof; and/or
 the island component polyamide resin has a relative viscosity of 2.4-3.0, preferably 2.5-2.9, and more preferably 2.6-2.8; and/or   the mass ratio of the island component to the sea component of the sea-island fiber is 20-80:80-20, and more preferably 30-70:70-30.   
     
     
         3 . The polyamide sea-island fiber according to  claim 1 , characterized in that the sea-island fiber includes a figured sea-island fiber and an unfigured sea-island fiber; and/or
 the number of the islands in the figured sea-island fiber is 16-500.   
     
     
         4 . The polyamide sea-island fiber according to  claim 1 , characterized in that the polyamide sea-island fiber has a fineness of 10-300 dtex, preferably 20-200 dtex, and more preferably 30-100 dtex; and/or
 the polyamide sea-island fiber has a break strength of 2.0-5.0 cN/dtex, preferably 2.5-4.5 cN/dtex, and more preferably 3.0-4.0 cN/dtex; and/or   the polyamide sea-island fiber has an elongation at break of 30-80%, preferably 40-70%, and more preferably 45-60%; and/or   the polyamide sea-island fiber has an initial modulus of 20-50 cN/dtex, preferably 23-45 cN/dtex, and more preferably 28-38 cN/dtex; and/or   after the polyamide sea-island fiber is split, the island component has a monofilament fineness of 0.001-0.2 dtex, preferably 0.005-0.1 dtex, and more preferably 0.01-0.05 dtex; and/or   the polyamide sea-island fiber has a K/S value of 15 or more, preferably 20 or more, and more preferably 25 or more; and/or   the polyamide sea-island fiber has a dye uptake of 90% or more, preferably 93% or more, and more preferably 96% or more; and/or   the polyamide sea-island fiber has a dyeing uniformity (grey scale) of grade 3.5 or more, preferably grade 4.0 or more, and more preferably grade 4.5 or more; and/or   the polyamide sea-island fiber has a soap fastness for fading of grade 3.0 or more, preferably grade 3.5 or more, more preferably grade 4.0 or more; and still more preferably 4.5 or more; and/or   the polyamide sea-island fiber has a soap fastness for staining of grade 3.0 or more, preferably grade 3.5 or more, more preferably grade 4.0 or more, and still more preferably grade 4.5 or more.   
     
     
         5 . A process for producing the figured sea-island fiber according to  claim 3 , characterized in that the process comprises the steps of:
 1. heating and melting the island component resin and the sea component resin respectively to obtain two melts; conveying the two melts into a spinning beam through a pipe; precisely metering each melt by a metering pump respectively, and injecting them into a sea-island type of composite spin pack in the spinning beam; distributing the two melts via a distribution pipe in the spin pack, and converging and extruding them at the entrance of a spinneret orifice; wherein the island component has a moisture content of less than 1500 ppm, and the sea component has a moisture content of less than 300 ppm; and   2. cooling, spinning finishing, drawing, heat setting and winding the as-formed fiber that is extruded in Step 1), so as to obtain the figured sea-island fiber.   
     
     
         6 . The process according to  claim 5 , characterized in that, in Step 1),
 the heating is performed in a screw extruder, wherein the screw extruder preferably includes five zones for heating;   for a screw for the island component, the temperature of a first zone is 200-260° C.; the temperature of a second zone is 230-280° C.; the temperature of a third zone is 240-290° C.; the temperature of a fourth zone is 260-300° C.; and the temperature of a fifth zone is 270-310° C.;   for a screw for the sea component, the temperature of a first zone is 120-220° C.; the temperature of a second zone is 140-240° C.; the temperature of a third zone is 160-260° C.; the temperature of a fourth zone is 180-280° C.; and the temperature of a fifth zone is 160-290° C.; and/or   the temperature of the spinning beam is 200-300° C.; and/or   the spin pack pressure of the island component is 10.0-15.0 MPa; the spin pack pressure of the sea component is 8.0-15.0 MPa; and the spin pack pressure difference between the sea component and the island component is controlled to be less than 4.0 MPa.   
     
     
         7 . The process according to  claim 5 , characterized in that, in Step 2),
 the cooling is conducted by quench air or cross air blow; an air speed is 0.2-1.2 m/s, preferably 0.2-1.0 m/s, and more preferably 0.3-0.8 m/s; the air temperature of the quench air is 15-30° C., preferably 20-27° C., and more preferably 22-25° C.; and/or   an oil pick up is 0.2-1.0 wt %, preferably 0.3-0.8 wt %, and more preferably 0.4-0.6 wt %; and/or   the drawing process is that the as-formed yarn that has been spinning finished is directed to a hot drawing roller through a feeding roller for drawing, and the drawing ratio is preferably 2.0-5.0, and more preferably 2.5-3.0; and/or   the heat setting temperature is 150-220° C., preferably 160-200° C., and more preferably 170-180° C.; and/or   the winding speed is 1000-6000 m/min, preferably 2000-5000 m/min, and more preferably 2500-4000 m/min.   
     
     
         8 . A process for producing the unfigured sea-island fiber according to  claim 3 , characterized in that the process comprises the steps of:
 a) uniformly mixing the island component and the sea component in a certain proportion and then heating and melting the mixture; conveying the resultant blended melt into a spinning beam through a pipe; precisely metering the blended melt by a metering pump, and injecting it into a one-component spin pack in the spinning beam; and extruding the blended melt through a spinneret orifice; wherein the island component has a moisture content of less than 1500 ppm; and the sea component has a moisture content of less than 300 ppm;   2. cooling, spinning finishing, drawing, heat setting and winding the as-formed fiber that is extruded to obtain the unfigured sea-island fiber.   
     
     
         9 . The process according to  claim 8 , wherein in Step a),
 the heating is performed in a screw extruder, wherein the screw extruder preferably includes five zones for heating; the temperature of a first zone is 180-240° C.; the temperature of a second zone is 200-260° C.; the temperature of a third zone is 220-270° C.; the temperature of a fourth zone is 240-280° C.; and the temperature of a fifth zone is 200-300° C.; and/or   the temperature of the spinning beam is 200-300° C.; and the spin pack pressure is 10.0-25.0 MPa.   
     
     
         10 . The process according to  claim 8 , wherein in Step b),
 the cooling is conducted by quench air or cross air blow; the air speed is 0.2-1.2 m/s, preferably 0.4-1.0 m/s, and more preferably 0.6-0.8 m/s; the air temperature of the quench air is 15-30° C., preferably 23-27° C., and more preferably 24-25° C.; and/or   the oil pick up is 0.2-1.0 wt %, preferably 0.3-0.8 wt %, and more preferably 0.4-0.6 wt %; and/or   the drawing process is that the as-formed yarn that has been spinning finished is directed to a hot drawing roller through a feeding roller for drawing, and the drawing ratio is preferably 2.0-5.0, and more preferably 2.5-3.0; and/or   the heat setting temperature is 150-220° C., preferably 160-200° C., and more preferably 170-180° C.; and/or   the winding speed is 1000-6000 m/min, preferably 2000-5000 m/min, and more preferably 2500-4000 m/min.   
     
     
         11 . Use of the polyamide sea-island fiber according to  claim 1  in the manufacture of imitation wools, imitation silks, imitation leathers, imitation peach skins, imitation suedes, high-density waterproof fabrics, high-performance cleaning clothes, high-performance adsorbing and filtering materials, highly oil absorptive materials, highly water absorptive materials, thermal insulation materials, medical materials, automotive trim materials, safety shoes, cases, handbags or sofas.