Manufacturing method of polyester fiber for airlaid nonwoven fabrics

Abstract

An object of the invention is to provide a polyester based fiber for airlaid nonwoven fabrics enabling one to manufacture an airlaid nonwoven fabric which is extremely excellent in airlaid web formability, especially in spinning properties from a screen, is satisfactory in texture and is bulky. This object can be achieved by a manufacturing method of a polyester fiber for airlaid nonwoven fabrics made of, as a fiber forming resin component, a polyester having a fineness of not more than 10.0 dtex or a fiber length of 8.0 mm or more, having a number of crimp of 8.5 peaks/25 mm or more, a percentage of crimp/number of crimp ratio of not more than 0.65 and a crimp modulus of elasticity of 70% or more and containing 80% by mole or more of an alkylene terephthalate repeating unit in the whole of repeating units, which includes drawing an undrawn yarn taken up at a spinning rate of not more than 1,500 m/min in a low draw ratio of from 0.60 to 1.20 times at a temperature of at least 10° C. higher than a glass transition temperature of the polyester and simultaneously subjecting to a fixed-length heat treatment.

1 . A manufacturing method of a polyester fiber for airlaid nonwoven fabrics made of, as a fiber forming resin component, a polyester having a fineness of not more than 10.0 dtex or a fiber length of 8.0 mm or more, having a number of crimp of 8.5 peaks/25 mm or more, a percentage of crimp/number of crimp ratio of not more than 0.65 and a crimp modulus of elasticity of 70% or more and containing 80% by mole or more of analkylene terephthalate repeating unit in the whole of repeating units, which includes drawing an undrawn yarn taken up at a spinning rate of not more than 1,500 m/min in a low draw ratio of from 0.60 to 1.20 times at a temperature of at least 10° C. higher than a glass transition temperature of the polyester and simultaneously subjecting to a fixed-length heat treatment. 
   
   
       2 . The manufacturing method of a polyester fiber according to  claim 1 , wherein the polyester fiber for airlaid nonwoven fabrics is made of a single polyester component. 
   
   
       3 . The manufacturing method of a polyester fiber according to  claim 2 , wherein the alkylene terephthalate is ethylene terephthalate. 
   
   
       4 . The manufacturing method of a polyester fiber according to  claim 2 , wherein the dry heat shrinkage percentage at 180° C. is from −20.0 to 2.0%. 
   
   
       5 . The manufacturing method of a polyester fiber according to  claim 1 , wherein the polyester fiber for airlaid nonwoven fabrics is a conjugated fiber made of a fiber forming resin component and a thermoadhesive resin component. 
   
   
       6 . The manufacturing method of a polyester fiber according to  claim 5 , wherein the alkylene terephthalate constituting the fiber forming resin component is ethylene terephthalate. 
   
   
       7 . The manufacturing method of a polyester fiber according to  claim 5 , wherein the thermoadhesive resin component is a polyolefin resin. 
   
   
       8 . The manufacturing method of a polyester fiber according to  claim 5 , wherein the thermoadhesive resin component is a crystalline copolyester. 
   
   
       9 . The manufacturing method of a polyester fiber according to  claim 5 , wherein prior to the fixed-length heat treatment, the undrawn yarn is drawn at a temperature of lower than a temperature of whichever is higher between a glass transition temperature of the thermoadhesive resin component and a glass transition temperature of the fiber forming resin component and then subjected to an overfeed fixed-length heat treatment at a temperature of at least 10° C. higher than a temperature of whichever is higher between a glass transition temperature of the thermoadhesive resin component and a glass transition temperature of the fiber forming resin component in a draw ratio of from 0.60 to 0.90 times.