Water soluble fibers with post process modifications and articles containing same

A post-process modified fiber having a surface region and an interior region, the fiber comprising:

• a polymer comprising at least one of a vinyl acetate moiety or a vinyl alcohol moiety chemically modified after fiber formation with a modification agent,
• the fiber having a transverse cross-section including the interior region comprising the polymer having a first degree of modification and the surface region comprising the polymer having a second degree of modification greater than the first degree of modification,
• wherein the polymer comprising at least one of a vinyl acetate moiety or a vinyl alcohol moiety without modification comprises a polyvinyl acetate homopolymer, a polyvinyl alcohol copolymer comprising a copolymer of vinyl acetate and vinyl alcohol, or any combination thereof.

A post-process modified fiber having a surface region and an interior region, the fiber comprising:

• a polymer comprising at least one of a vinyl acetate moiety or a vinyl alcohol moiety chemically modified after fiber formation with a modification agent, wherein the polymer comprising at least one of a vinyl acetate moiety or a vinyl alcohol moiety chemically modified with the modification agent is chemically bonded with a moiety of the modification agent,
• the fiber having a transverse cross-section including the interior region comprising the polymer having a first degree of modification and the surface region comprising the polymer having a second degree of modification greater than the first degree of modification.

A post-process modified, water-soluble fiber having a longitudinal axis and a transverse cross-section perpendicular to the longitudinal axis, the fiber further having a core-sheath structure along at least a portion of the longitudinal axis, the fiber comprising:

• a core region comprising a polymer comprising at least one of a vinyl acetate moiety and a vinyl alcohol moiety chemically modified after fiber formation with a modification agent and having a first degree of modification, and
• a sheath region comprising the polymer comprising at least one of a vinyl acetate moiety and a vinyl alcohol moiety chemically modified after fiber formation with the modification agent and having a second degree of modification greater than the first degree of modification.