Polylactic acid filament nonwoven fabric and production method thereof
AssigneeUnitika Ltd.
InventorAtsushi Matsunaga
Life of this patent
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Abstract
A nonwoven fabric formed of composite filaments by a spunbond method is disclosed. The composite filament includes a polylactic acid polymer having a melting point of 160° C. or higher and an aliphatic polyester polymer having a melting point lower, by 50° C. or more, than the melting point of the polylactic acid polymer. The aliphatic polyester polymer forms at least a portion of the filament surface. The aliphatic polyester polymer includes as the constituent components thereof 1,4-butanediol and succinic acid, and at the same time, includes 0.1 to 1% by mass of an amide wax.
Claims8
A nonwoven fabric which is formed of composite filaments by a spunbond method, wherein:
- the composite filament comprises a polylactic acid polymer having a melting point of not lower than 160° C. and an aliphatic polyester polymer having a melting point lower, by not less than 50° C., than the melting point of the polylactic acid polymer;
- the aliphatic polyester polymer forms at least a portion of a filament surface;
- and
- the aliphatic polyester polymer comprises as constituent components thereof 1,4-butanediol and succinic acid, and at the same time, comprises 0.1 to 1% by mass of an amide wax.
A production method of a nonwoven fabric comprising the steps of:
- preparing a polylactic acid polymer having a melting point of not lower than 160° C. and an aliphatic polyester polymer which comprises, as constituent components thereof, 1,4-butanediol and succinic acid and has a melting point lower, by not less than 50° C., than the melting point of the polylactic acid polymer;
- mixing an amide wax so as to have a content of 0.1 to 1% by mass in the aliphatic polyester polymer;
- melting separately the polylactic acid polymer and the aliphatic polyester polymer at a temperature of (Tm+75)° C. to (Tm+120)° C. wherein the Tm is the melting point of the aliphatic polyester polymer;
- performing spinning by using a composite spinneret which allows the aliphatic polyester polymer to form at least a portion of a filament surface in a filament cross section;
- cooling, drawing and subsequently spreading-open filaments that have been spin-twisted from the spinneret;
- and
- forming a nonwoven web by depositing thus obtained filaments.
Dependencies are inferred from the claim text.