Cross-linking resin saturant and method

Claim 1

The method of preparing a resin impregnated non-woven web having thermoplastic characteristics at temperatures below 190° F. and thermoset characteristics at temperatures above 190° F. comprising: (a) preparing a cross-linking latex composition by (1) charging a reaction vessel with a small amount of a seed latex polymer along with an initiator in an aqueous phase to provide nucleating sites for polymerization, (2) adding, substantially continuously, monomers and emulsifiers at a controlled rate, said monomer consisting essentially of about 59 parts by weight styrene, about 41 parts by weight ethylacrylate, and 2 parts by weight N-methylolacrylamide, the addition taking place at about 150° F. over a 41/2 hour period, (3) post cooking the latex composition up to about three additional hours to reduce the free monomers content of the latex composition, (4) adjusting the latex composition after polymerization is completed from as manufactured state to a pH value between 6.0 and 8.0 with a neutralizing agent; (b) saturating a non-woven web with the adjusted latex composition; (c) drying the saturated web at a temperature below about 190° F. whereby an impregnated thermoplastic non-woven web having thermoset properties above 190° F. is produced.

Claim 2

The method of preparing a resin impregnated non-woven web having thermoplastic characteristics at temperatures below 190° F. and thermoset characteristics at temperatures above 190° F. comprising: (a) preparing a cross-linking latex composition by (1) charging a reaction vessel with a small amount of a seed latex polymer along with an initiator in an aqueous phase to provide nucleating sites for polymerization, (2) adding, substantially continuously, monomers and emulsifiers at a controlled rate, said monomer consisting essentially of about 59 parts by weight styrene, about 41 parts by weight ethylacrylate, and 2 parts by weight N-methylolacrylamide, the addition taking place at about 150° F. over a 41/2 hour period, (3) post cooking the latex composition up to about three additional hours to reduce the free monomers content of the latex composition, (4) adjusting the latex composition after polymerization is completed from as manufactured state to a pH value between 6.0 and 8.0 with a neutralizing agent; (b) saturating a non-woven web with the adjusted latex composition; (c) drying the saturated web at a temperature below about 190° F. whereby an impregnated thermoplastic non-woven web having thermoset properties above 190° F. is produced.

Claim 4

A method of preparing a resin impregnated non-woven fibrous web having thermoplastic characteristics at temperatures below 190° F. and thermoset characteristics at temperatures above about 190° F. comprising: (a) providing a storage stable one-package polymerized latex composition consisting essentially of the polymerization reaction product of (1) from about 40 to about 70 parts by weight of a first monomer selected from styrene, vinylidene chloride, methylmethacrylate, butylmethacrylate and mixtures thereof, (2) from about 30 to about 60 parts by weight of a second monomer selected from methylacrylate, ethylacrylate and butylacrylate, proplyacrylate, 2-ethylhexylacrylate, mixtures thereof, and, (3) from about 0.5 to about 6.0 parts by weight of N-methylolacrylamide; said composition having been treated with a neutralizing agent after completion of polymerization reaction to prevent cross-linking below temperatures of 190° F.; (b) applying said neutralized composition to a non-woven fibrous web to impregnate the web, and (c) drying the impregnated non-woven fibrous web at a temperature below 190° F.

Claim 5

A method of preparing a resin impregnated non-woven fibrous web having thermoplastic characteristics at temperatures below 190° F. and thermoset characteristics at temperatures above about 190° F. comprising: (a) providing a storage stable one-package polymerized latex composition consisting essentially of the polymerization reaction product of (1) from about 40 to about 70 parts by weight of a first monomer selected from styrene, vinylidene chloride, methylmethacrylate, butylmethacrylate and mixtures thereof, (2) from about 30 to about 60 parts by weight of a second monomer selected from methylacrylate, ethylacrylate and butylacrylate, proplyacrylate, 2-ethylhexylacrylate, mixtures thereof, and, (3) from about 0.5 to about 6.0 parts by weight of N-methylolacrylamide; said composition having been treated with a neutralizing agent after completion of polymerization reaction to prevent cross-linking below temperatures of 190° F.; (b) applying said neutralized composition to a non-woven fibrous web to impregnate the web, and (c) drying the impregnated non-woven fibrous web at a temperature below 190° F.