Method for producing fibril fibrous structures

Claim 1

A method for producing fibrillated fibrous structures which comprises forming into a knit fabric, or a woven fabric, or a non-woven fabric, fabrillatable composite filaments consisting essentially of (A) a polyamide and (B) a component having poor affinity to said polyamide and selected from the group consisting of a polyester, a polyolefin and polyacrylonitrile, each of said composite filaments in transverse cross-section consisting of at least three integral polyamide layers of substantially uniform thickness which comprise from 10 to 35 percent of the cross-sectional area of the filament and which diverge substantially radially in the outward direction and extend to the perimeter of the filament, said layers dividing said component B of said filament into at least three separate segments which extend to the perimeter of the filament; immersing said fabric in an aqueous emulsion consisting essentially of water, from 1.5 to 50 percent by weight of an alcohol selected from the group consisting of benzyl alcohol and phenylethyl alcohol, and a surfactant in an amount in the range of 5 to 20 percent by weight, based on the weight of said alcohol, and effective to impart to said emulsion a percent transmittancy of less than 20 percent; and maintaining said fabric in contact with said emulsion under conditions effective to swell and shrink component A and to minimize swelling and shrinking of component B for a period of time effective to separate at least about 70% of said segments of component B from said polyamide layers whereby to fibrillate the composite filaments to impart a soft silky feel and a bulky appearance to the fibrous structure, and in the case of knit and woven fabrics to shrink the arena of the fabric from 10 to 60 percent, to increase the thickness of the fabric more than 20 percent and wherein the ratio of said thickness increase percent to said area shrinkage percent is more than 2, and in the case of non-woven fabrics to shrink its volume from 10 to 40 percent.

Claim 2

A method for producing fibrillated fibrous structures which comprises forming into a knit fabric, or a woven fabric, or a non-woven fabric, fabrillatable composite filaments consisting essentially of (A) a polyamide and (B) a component having poor affinity to said polyamide and selected from the group consisting of a polyester, a polyolefin and polyacrylonitrile, each of said composite filaments in transverse cross-section consisting of at least three integral polyamide layers of substantially uniform thickness which comprise from 10 to 35 percent of the cross-sectional area of the filament and which diverge substantially radially in the outward direction and extend to the perimeter of the filament, said layers dividing said component B of said filament into at least three separate segments which extend to the perimeter of the filament; immersing said fabric in an aqueous emulsion consisting essentially of water, from 1.5 to 50 percent by weight of an alcohol selected from the group consisting of benzyl alcohol and phenylethyl alcohol, and a surfactant in an amount in the range of 5 to 20 percent by weight, based on the weight of said alcohol, and effective to impart to said emulsion a percent transmittancy of less than 20 percent; and maintaining said fabric in contact with said emulsion under conditions effective to swell and shrink component A and to minimize swelling and shrinking of component B for a period of time effective to separate at least about 70% of said segments of component B from said polyamide layers whereby to fibrillate the composite filaments to impart a soft silky feel and a bulky appearance to the fibrous structure, and in the case of knit and woven fabrics to shrink the arena of the fabric from 10 to 60 percent, to increase the thickness of the fabric more than 20 percent and wherein the ratio of said thickness increase percent to said area shrinkage percent is more than 2, and in the case of non-woven fabrics to shrink its volume from 10 to 40 percent.

Claim 14

A method for producing fibrillated filaments which comprises knitting into a knitted fabric fibrillatable composite filaments consisting essentially of (A) a polyamide and (B) a component having poor affinity to said polyamide and selected from the group consisting of a polyester, a polyolefin and polyacrylonitrile, each of said composite filaments in transverse cross-section consisting of at least three integral polyamide layers of substantially uniform thickness which comprise from 10 to 35 perccent of the cross-sectional area of the filament and which diverge substantially radially in the outward direction and extend to the perimeter of the filament, said layers dividing said component B of said filament into at least three separate segments which extend to the perimeter of the filament; immersing said knitted fabric in an aqueous emulsion consisting essentially of water, from 1.5 to 50 percent by weight of an alcohol selected from the group consisting of benzyl alcohol and phenylethyl alcohol, and a surfactant in an amount in the range of 5 to 20 percent by weight, based on the weight of said alcohol, and effective to impart to said emulsion a percent transmittancy of less than 20 percent, and maintaining said knitted fabric in contact with said emulsion under conditions effective to swell and shrink component A and to minimize swelling and shrinking of component B for a period of time effective to separate at least about 70% of said segments of component B from said polyamide layers whereby to fibrillate the composite filaments and to shrink the area of the fabric from 10 to 60 percent, to increase the thickness of the fabric more than 20 percent and wherein the ratio of said thickness increase percent to said area shrinkage percent is more than 2, and then unknitting the knitted fabric to obtain fibrillated filaments.

Claim 15

A method for producing fibrillated filaments which comprises knitting into a knitted fabric fibrillatable composite filaments consisting essentially of (A) a polyamide and (B) a component having poor affinity to said polyamide and selected from the group consisting of a polyester, a polyolefin and polyacrylonitrile, each of said composite filaments in transverse cross-section consisting of at least three integral polyamide layers of substantially uniform thickness which comprise from 10 to 35 perccent of the cross-sectional area of the filament and which diverge substantially radially in the outward direction and extend to the perimeter of the filament, said layers dividing said component B of said filament into at least three separate segments which extend to the perimeter of the filament; immersing said knitted fabric in an aqueous emulsion consisting essentially of water, from 1.5 to 50 percent by weight of an alcohol selected from the group consisting of benzyl alcohol and phenylethyl alcohol, and a surfactant in an amount in the range of 5 to 20 percent by weight, based on the weight of said alcohol, and effective to impart to said emulsion a percent transmittancy of less than 20 percent, and maintaining said knitted fabric in contact with said emulsion under conditions effective to swell and shrink component A and to minimize swelling and shrinking of component B for a period of time effective to separate at least about 70% of said segments of component B from said polyamide layers whereby to fibrillate the composite filaments and to shrink the area of the fabric from 10 to 60 percent, to increase the thickness of the fabric more than 20 percent and wherein the ratio of said thickness increase percent to said area shrinkage percent is more than 2, and then unknitting the knitted fabric to obtain fibrillated filaments.