Wet fixation of resins in fiber systems for durable press products

Claim 2

A process according to claim 1 wherein extraneous steam is introduced into the heating zone in the heating step.

Claim 3

A process according to claim 1 wherein the heating zone is heated to a temperature between about 150* and 220*C. by infrared heating elements and wherein escape of moisture from the heating zone is suppressed so as to keep the moisture content of the material above 20 percent.

Claim 4

A process according to claim 1 wherein the said acid- and polymer former-containing material is heated in the said heating zone by being passed at a high speed ovEr a set of steam-heated, rotating dry cans having a surface temperature of from about 100* to 160*C.

Claim 5

A process for imparting shape retention properties to cellulosic fiber-containing material which comprises: continuously applying a liquid solution adjusted to an acid pH of between about 1 and 4 and containing a water soluble, hardenable polymer former to said material in an amount sufficient to deposit thereon at least about 3 percent of said polymer former based on dry weight of said material, continuously passing said material with applied acid solution through a heating zone which is maintained at a temperature of at least about 100*C. while maintaining the moisture content of the material therein at not less than 20 percent, the dwell time of the material in the heating zone being limited to from about 10 seconds to about 90 seconds, thereby wet-fixing on said material between about 3 percent and 10 percent insoluble resin and-on (dry basis) while avoiding any effective cross-linking or creaseproofing of said material, continuously raising the pH of the material to at least about 6 promptly after its emergence from the aforesaid wet-fixation zone and washing the wet-fixed material to remove water soluble substances therefrom while avoiding effective cross-linking or creaseproofing of said material, thereby substantially preventing further reaction and migration of the polymer former, continuously applying to said material a cellulose crosslinking agent other than said polymer former either simultaneously with the latter or after wet-fixation of the latter, said crosslinking agent being applied in an amount sufficient to make the material shape retentive upon curing, and further continuously applying to the material an acid acting curing catalyst so that the resulting material may be ultimately dry cured and durable press properties may thus be imparted thereto.

Claim 6

A process according to claim 6 wherein said material contains at least 15 percent cotton fiber.

Claim 7

A process according to claim 6 wherein said curing catalyst is an acid acting salt selected from the group consisting of zinc chloride, zinc nitrate, magnesium chloride and ammonium chloride.

Claim 8

A process according to claim 6 wherein the duration of the wet-fixation step preceding the neutralization step is limited to between about 10 and 40 seconds and is kept substantially to the minimum necessary to insolubilize the polymer former on the material.

Claim 9

A process according to claim 6 wherein the material having the polymer former and crosslinking agent applied thereto is shaped into a garment after the wet-fixation step and prior to being dry cured.

Claim 10

A process according to claim 6 wherein the said acid- and polymer former-containing material is heated in the said heating zone by being continuously passed at a high speed over a set of steam-heated, rotating dry cans having a surface temperature of from about 100* to 160*C.

Claim 11

A process according to claim 6 wherein said wet-fixation step is carried out in a steamer at a temperature between about 105* and about 140*C. for a dwell time of between about 10 and 90 seconds.

Claim 12

A process according to claim 12 wherein the material padded with said aqueous liquid is dried to a water content between about 20 and 40 percent prior to being steamed in the wet-fixation step.

Claim 13

A process according to claim 12 wherein said polymer former is a melamine-formaldehyde precondensate and is applied from an aqueous solution at a pH between about 1 and 3 in which it is contained at a concentration of from between about 5 and 25 weight percent.

Claim 14

A process according to claim 14 wherein the polymer former and the crosslinker are applied to the material simultaneously from a single solution wherein each is contained in a concentration between about 5 and 10 percent.

Claim 15

A process according to claim 15 wherein the cross-linker is a member of the class consisting of formaldehyde, glyoxal, glutaraldehyde, hydroxy N-methylol ethylene ureas, N-methylol cyclic ethylene ureas, N-methylol propylene ureas, triazones, N-methylol carbamates, and mixtures thereof.

Claim 16

A wet-fixation process characterized by improved resin fixation efficiency in the production of cotton-containing textile material suitable for the fabrication of durable press apparel therefrom, which process comprises: continuously applying an aqueous liquid adjusted to an acid pH of between about 1 and 4 and containing between about 5 and 25 percent of a water soluble, hardenable polymer former possessing reactive N-methylol groups to said material in an amount sufficient to deposit thereon at least about 3 percent of said polymer former based on dry weight of said material, continuously passing said acid- and polymer former-containing material through a steaming zone containing a substantially saturated steam atmosphere at a temperature between about 100* and 140*C. at a rate corresponding to a dwell time in said zone of about 10 to 90 seconds and until said polymer former is wet-fixed on said material in the form of a water insoluble resin at a dry add-on of between about 5 and 10 percent but without effectively cross-linking or creaseproofing said material, and continuously neutralizing the acid-containing material with an aqueous solution of alkali promptly after completion of the aforesaid wet-fixation step while avoiding any effective cross-linking or creaseproofing of said material, thereby substantially preventing further reaction and migration of the polymer former.

Claim 17

A process according to claim 17 wherein said aqueous liquid applied to said material is at a pH between about 2 and 3 and contains both a polymer former and a crosslinker, each in a concentration from between about 5 to about 10 percent, and wherein said material after being neutralized with alkali is washed to remove water soluble matter therefrom, dried, impregnated with an aqueous solution of a latent curing catalyst, dried again at a temperature below about 90*C., and ultimately dry cured after manufacture of a garment therefrom, thereby imparting durable press properties thereto.