Nonwoven fabric

Abstract

Provided is a nonwoven fabric which is formed from a resin composition and has improved antifouling properties, sound insulation properties, coefficient of friction, and texture. This nonwoven fabric is formed from a resin composition which contains (1) a thermoplastic resin and (2) a fluorine-containing copolymer, and wherein: the thermoplastic resin (1) is a polypropylene; and the fluorine-containing copolymer (2) is a copolymer which has (a) a repeating unit that is formed of a fluorine-containing monomer represented by formula CH 2 ═C(—X)—C(═O)—Y—Z—Rf and (b) a repeating unit that is formed of a non-fluorine monomer having a hydrocarbon group with 14 or more carbon atoms, and which has a weight average molecular weight of 2,500-20,000.

1 . A nonwoven fabric comprising a resin composition comprising:
 (1) a thermoplastic resin, and   (2) a fluorine-containing copolymer,   wherein the thermoplastic resin (1) is polypropylene, and   the fluorine-containing copolymer (2) is a copolymer which comprises:   (a) a repeating unit formed from a fluorine-containing monomer represented by the formula:
   CH 2 ═C(—X)—C(═O)—Y—Z—Rf
 
   wherein X is a hydrogen atom, a monovalent organic group or a halogen atom,   Y is —O— or —NH—,   Z is a direct bond or an divalent organic group, and   Rf is a fluoroalkyl group having 4 to 6 carbon atoms, and   (b) a repeating unit formed from a fluorine-free monomer containing a hydrocarbon group having at least 14 carbon atoms, and
 which has a weight-average molecular weight of 2,500 to 20,000. 
   
     
     
         2 . The nonwoven fabric according to  claim 1 , wherein, in the fluorine-containing monomer (a), X is a methyl group and Z is a linear alkylene group or branched alkylene group having 1-20 carbon atoms. 
     
     
         3 . The nonwoven fabric according to  claim 1 , wherein the fluorine-free monomer (b) is a (meth)acrylate ester in which an acryloyloxy group is bonded to a monovalent non-cyclic hydrocarbon group or cyclic hydrocarbon group having 14-30 carbon atoms. 
     
     
         4 . The nonwoven fabric according to  claim 1 , wherein the fluorine-free monomer (b) is an acrylate ester in which an alpha-position is a hydrogen atom. 
     
     
         5 . The nonwoven fabric according to  claim 1 , wherein the fluorine-containing copolymer (2) further comprises (c) a repeating unit formed from a fluorine-free crosslinkable monomer, and the amount of the monomer (c) is 0.1 to 100 parts by weight, based on 100 parts by weight of the total of the monomer (a) and the monomer (b). 
     
     
         6 . The nonwoven fabric according to  claim 1 , wherein the fluorine-containing copolymer (2) has a weight-average molecular weight of 3,000 to 15,000. 
     
     
         7 . The nonwoven fabric according to  claim 1 , wherein, in the fluorine-containing copolymer (2), a weight ratio of the fluorine-containing monomer (a) to the fluorine-free monomer (b) is 35:65 to 70:30 and the amount of the fluorine-containing monomer (a) is at least 25 wt %, based on the fluorine-containing copolymer. 
     
     
         8 . The nonwoven fabric according to  claim 1 , wherein the resin composition has a melt flow rate (MFR) of at least 600 g/10 minutes. 
     
     
         9 . The nonwoven fabric according to  claim 1 , wherein a fiber in the nonwoven fabric has an average fiber diameter of 0.1 to 5 micrometers. 
     
     
         10 . The nonwoven fabric according to  claim 1 , wherein the amount of the fluorine-containing copolymer (2) is 0.01 to 50 parts by weight, based on 100 parts by weight of the thermoplastic resin (1). 
     
     
         11 . A method of producing a nonwoven fabric, comprising steps of:
 (i) mixing a thermoplastic resin (1) with a fluorine-containing copolymer (2) to obtain a resin composition; and   (ii) spinning fibers from a melt of the resin composition which is pressure-fed to a die by a melt blowing method, with a nozzle having a large number of arranged small holes,   wherein the thermoplastic resin (1) is polypropylene, and   the fluorine-containing copolymer (2) is a copolymer which comprises:   (a) a repeating unit formed from a fluorine-containing monomer represented by the formula:
   CH 2 ═C(—X)—C(═O)—Y—Z—Rf
 
   wherein X is a hydrogen atom, a monovalent organic group or a halogen atom,   Y is —O— or —NH—,   Z is a direct bond or an divalent organic group, and   Rf is a fluoroalkyl group having 4 to 6 carbon atoms, and   (b) a repeating unit formed from a fluorine-free monomer containing a hydrocarbon group having at least 14 carbon atoms, and   which has a weight-average molecular weight of 2,500 to 20,000.