Modified polylactic acid fibers

Patent metadata

Field	Value
Publication number	US-8936740-B2
Application number	US-85601210-A
Country	US
Kind code	B2
Filing date	Aug 13, 2010
Priority date	Aug 13, 2010
Publication date	Jan 20, 2015
Grant date	Jan 20, 2015

Abstract

A method for forming biodegradable fibers is provided. The method includes blending polylactic acid with a polyepoxide modifier to form a thermoplastic composition, extruding the thermoplastic composition through a die, and thereafter passing the extruded composition through a die to form a fiber. Without intending to be limited by theory, it is believed that the polyepoxide modifier reacts with the polylactic acid and results in branching of its polymer backbone, thereby improving its melt strength and stability during fiber spinning without significantly reducing glass transition temperature. The reaction-induced branching can also increase molecular weight, which may lead to improved fiber ductility and the ability to better dissipate energy when subjected to an elongation force. To minimize premature reaction, the polylactic acid and polyepoxide modifier are first blended together at a relatively low temperature(s). Nevertheless, a relatively high shear rate may be employed during blending to induce chain scission of the polylactic acid backbone, thereby making more hydroxyl and/or carboxyl groups available for subsequent reaction with the polyepoxide modifier. Once blended, the temperature(s) employed during extrusion of the blended composition can be selected to both melt the composition and initiate a reaction of the polyepoxide modifier with hydroxyl and/or carboxyl groups of the polylactic acid. Through selective control over this method, the present inventors have discovered that the resulting fibers may exhibit good mechanical properties, both during and after melt spinning.

First claim

What is claimed is:

1. A method for forming a polylactic acid fiber, the method comprising;
melt blending a polylactic acid with a polyepoxide modifier and a polymeric toughening additive to form a thermoplastic composition, wherein the melt blending occurs at a temperature above the melting point of the polylactic acid and below a temperature of about 230° C., the polyepoxide modifier having a number average molecular weight of from about 15,000 to about 250,000 grams per mole, w…

Assignees

• Topolkaraev Vasily A
• Mceneany Ryan J
• Eby Tom
• Lark Tyler J
• Kimberly Clark Co

Inventors

• Topolkaraev Vasily A
• Mceneany Ryan J
• Eby Tom
• Lark Tyler J

Classifications

• C08L23/0884

  Chemistry & Metallurgy · mapped topic

• D01F1/02

  Textiles & Paper · mapped topic

• D04H3/011

  Textiles & Paper · mapped topic

• C08L67/04

  Chemistry & Metallurgy · mapped topic

• D04H3/16

  Textiles & Paper · mapped topic