Patent ID: 8377353

Claim:
A process for making a conjugate fiber, wherein at least one segment of the conjugate fiber is a PLA resin having, per gram of PLA resin in the segment, at least 20 J of crystallites having a melting temperature of at least 200° C., comprising a) coextruding 1) a mixture of a high-D PLA starting resin and a high-L PLA starting resin with 2) a second resin which is not a mixture of a high-D PLA starting resin and a high-L PLA starting resin, to form a segmented extrudate in which at least one segment contains a mixture of a high-D PLA resin and a high-L PLA resin and at least one other segment contains the second resin; b) cooling the extrudate to below the crystalline melting temperature of each of the PLA resins to form a conjugate fiber; and c) heat treating at least the segment or segments of the conjugate fiber that contain the mixture of a high-D PLA resin and a high-L PLA resin at a temperature between the glass transition temperature of the PLA starting resins and the crystallization melting temperature of the PLA starting resins for a period of time such that the segments or segments containing the mixture of the high-D PLA starting resin and the high-L starting resin form, per gram of PLA resins in said segment or segments, at least 20 Joules of crystallites having a crystalline melting temperature of at least 200° C.