Nonwoven fabrics formed from polyethylene glycol modified polyester fibers and method for making the same

A nonwoven fabric formed of polyethylene glycol modified copolyester staple fibers that provide exceptional moisture management characteristics, said copolyester staple fibers comprising:

• polyethylene terephthalate in an amount sufficient for said copolyester staple fibers to possess dimensional stability properties substantially similar to those of conventional, unmodified polyethylene terephthalate fibers;
• polyethylene glycol in an amount sufficient for said copolyester staple fibers to possess wicking characteristics that are superior to those of conventional, unmodified polyethylene terephthalate fibers, wherein the polyethylene glycol has an average molecular weight less than about 5000 g/mol;
• and
• chain branching agent in an amount less than about 0.0014 mole-equivalent branches per mole of standardized polymer, the standardized polymer being unmodified polyethylene terephthalate;
• wherein said copolyester staple fibers comprise polymer chains formed from structural units consisting essentially of either diol monomers and aromatic non-substituted diacid monomers, or diol monomers, aromatic non-substituted diacid monomers, and branching agent monomers;
• and
• wherein said copolyester staple fibers have a mean intrinsic viscosity of at least about 0.67 dl/g.

A method of making a nonwoven fabric having exceptional wicking characteristics, comprising:

• copolymerizing polyethylene glycol and chain branching agent into polyethylene terephthalate in the melt phase to form a copolyester composition that comprises polymer chains formed from structural units consisting essentially of diol monomers, aromatic non-substituted diacid monomers, and branching agent monomers, and that has an intrinsic viscosity of at least about 0.67 dl/g;
• wherein the polyethylene terephthalate is present in the copolyester composition in an amount sufficient for fibers made from the copolyester composition to possess dimensional stability properties substantially similar to those of conventional, unmodified polyethylene terephthalate fibers;
• wherein the polyethylene glycol has an average molecular weight of less than about 5000 g/mol and is present in an amount sufficient for fibers made from the copolyester composition to possess wicking characteristics that are superior to those of conventional, unmodified polyethylene terephthalate fibers;
• and
• wherein the chain branching agent is present in the copolyester composition in an amount less than about 0.0014 mole-equivalent branches per mole of standardized polymer, the standardized polymer being unmodified polyethylene terephthalate;
• thereafter spinning the copolyester composition into copolyester filaments;
• forming the copolyester filaments into staple fibers;
• and
• forming the copolyester staple fibers into a nonwoven fabric.

A method of making a nonwoven fabric having exceptional wicking characteristics, comprising:

• copolymerizing polyethylene glycol into polyethylene terephthalate in the melt phase to form a copolyester composition;
• then polymerizing the copolyester composition in the solid phase until the copolyester composition is capable of achieving a melt viscosity that facilitates the spinning of fibers;
• thereafter spinning the copolyester composition into copolyester filaments;
• forming the copolyester filaments into staple fibers;
• and
• forming the copolyester staple fibers into a nonwoven fabric.