Alkylphenol ethoxylate-free surfactant package for polymer emulsions
This invention is directed to formation of a creped nonwoven web. The creped web is formed in a creping process using a polymer emulsion binder formed in an alkylphenol ethoxylate-free surfactant system. The surfactant system comprises a combination of a specific active anionic surfactant (sodium laureth sulfate containing 1 to 12 moles of ethylene oxide) and a specific active nonionic surfactant (a secondary alcohol ethoxylate containing 7 to 30 moles of ethylene oxide or an ethoxylated branched primary alcohol containing 3 to 30 moles of ethylene oxide.)
1. In a method for forming a bonded and creped nonwoven web which comprises: applying a polymer emulsion binder to a nonwoven web to form a coated nonwoven web, drying the coated nonwoven web, and subsequently creping said dried coated nonwoven web in a crepe process; the improvement which comprises using an alkylphenol ethoxylate-free polymer emulsion binder formed by emulsion polymerizing one or more ethylenically unsaturated monomers and one or more crosslinking monomers, in the presence of an anionic surfactant comprised of a sodium laureth sulfate having 1 to 12 moles of ethylene oxide and a nonionic surfactant comprising a secondary alcohol ethoxylate containing 7 to 30 moles of ethylene oxide or an ethoxylated branched primary alcohol containing 3 to 30 moles of ethylene oxide, said primary or secondary alcohol containing 7 to 18 carbons.
2. The method of claim 1 wherein the one or more ethylenically unsaturated monomers is selected from the group consisting of a vinyl ester, ethylene, styrene, butadiene, a C 1-8 alkyl ester of acrylic, a C 1-8 alkyl ester of methacrylic acid, a diacrylate, an unsaturated carboxylic acid, acrylonitrile, and a vinyl ester of a C 2-10 alcohol; and the one or more crosslinking monomers is selected from the group consisting of a N—(C 1-4 ) alkylol(meth)acrylamide, i-butoxy methylacrylamide, acrylamidoglycolic acid, acrylamidobutyraldehyde, a dialkyl acetal of acrylamidobutyraldehyde, said alkyl having 1 to 4 carbons, and acrylamide in combination with one or more of the aforementioned crosslinking monomers.
3. The method of claim 1 wherein the one or more ethylenically unsaturated monomer is selected from the group consisting of vinyl acetate, ethylene, styrene, butadiene, methyl(meth)acrylate, ethyl(meth)acrylate, butyl(meth)acrylate, hexyl(meth)acrylate, 2-ethylhexyl(meth)acrylate, acrylic acid, methacrylic acid, crotonic acid, itaconic acid, maleic acid, and acrylonitrile; and the one or more crosslinking monomers is selected from the group consisting of a N—(C 1-4 )alkylol(meth)acrylamide, and acrylamide in combination with a N—(C 1-4 )alkylol(meth)acrylamide.
4. The method of claim 1 wherein the crosslinking monomer is N-methylol acrylamide.
5. The method of claim 1 wherein said anionic surfactant is a sodium laureth sulfate containing 2 to 5 moles of ethylene oxide and said nonionic surfactant is a secondary alcohol ethoxylate having 12 to 20 moles of ethylene oxide or an ethoxylated branched primary alcohol containing 9 to 20 moles of ethylene oxide, and the weight ratio of anionic to nonionic surfactant ranges from 4:1 to 1.5:1.
6. The method of claim 1 wherein said anionic surfactant is a sodium laureth sulfate containing 4 moles of ethylene oxide and said nonionic surfactant is a secondary alcohol ethoxylate having 20 moles of ethylene oxide.
7. The method of claim 6 wherein said nonionic surfactant is tridecanol ethoxylate containing 9 to 20 moles of ethylene oxide.
8. The method of claim 1 wherein the weight ratio of anionic surfactant to nonionic surfactant is 65:35.
9. The method of claim 1 wherein the creping process is a double recrepe process.
10. A creped web formed by the method of claim 1 .
11. A creped web formed by the method of claim 6 .
12. A creped web formed by the method of claim 9 .