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AssigneeKimberly-Clark Worldwide, Inc.
InventorsBo Shi, James H. Wang, Aimin He
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A fiber formed from a thermoplastic composition that contains a thermoplastic starch and an aliphatic-aromatic copolyester is provided. The copolyester enhances the strength of the starch-containing fibers and facilitates the ability of the starch to be melt processed. Due to its relatively low melting point, the copolyester may also be extruded with the thermoplastic starch at a temperature low enough to avoid substantial removal of the moisture in the starch. Furthermore, the copolyester is also modified with an alcohol to contain one or more hydroxyalkyl or alkyl terminal groups. By selectively controlling the conditions of the alcoholysis reaction (e.g., alcohol and copolymer concentrations, temperature, etc.), the resulting modified aliphatic-aromatic copolyester may have a relatively low molecular weight. Such low molecular weight polymers have the combination of a higher melt flow index and lower apparent viscosity, which is useful in a variety of fiber forming applications, such as meltblowing nonwoven webs.
A fiber formed from a thermoplastic composition that comprises from about 5 wt. % to about 40 wt. % of at least one thermoplastic starch and from about 60 wt. % to about 95 wt. % of an aliphatic-aromatic copolyester terminated with an alkyl group, hydroxyalkyl group, or a combination thereof, wherein the copolyester has a melt flow index of from about 10 to about 100 grams per 10 minutes, determined at a load of 2160 grams and temperature of 190° C. in accordance with ASTM Test Method D1238-E.
Dependencies are inferred from the claim text.