Emulsion binders containing low residual formaldehyde and having improved tensile strength
AssigneeNational Starch and Chemical Investment Holding Corporation
InventorsPaul R. Mudge, James L. Walker, Ronald Pangrazi
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Abstract
The free formaldehyde content of the emulsion polymer, the amount of emitted formaldehyde and, even more particularly, of the finished nonwoven or textile may be substantially reduced by the use of a particular initiator system comprising a hydrophobic hydroperoxide and ascorbic acid. Moreover, this reduction in formaldehyde levels is accompanied by an unexpected improvement in the tensile properties of the emulsion binders.
Claims9
A nonwoven product comprising a nonwoven web of fibers bonded together with a binder which comprises an emulsion polymer consisting of at least 50% by weight vinyl acetate;
- 0 to 48% by weight of a comonomer selected from the group consisting of vinyl chloride, vinyl esters of aliphatic carboxylic acids containing 1-20 carbon atoms, dialkyl esters of maleic and fumaric acid containing 1-8 carbon atoms in each alkyl group and C1-C8 alkyl acrylates and methacrylates;
- 0 to 30% by weight of ethylene;
- 0 to 4% by weight of an ethylenically unsaturated carboxylic acid;
- 0 to 1% by weight of a polyunsaturated copolymerizable monomer;
- 0 to 5% by weight acrylamide or methacrylamide;
- and a crosslinking monomer, said monomer present in an amount of from 0.5 to 10%;
- said monomer selected from the group consisting of N-methylol acrylamide, N-methylol methacrylamide, N-methylol allyl carbamate, iso-butoxy methyl acrylamide and n-butoxy methyl acrylamide, the emulsion polymer having been polymerized in a medium consisting essentially of water and a stabilizing system consisting of an emulsifier and/or polyvinyl alcohol using 0.05 to 3% by weight of a hydrophobic hydroperoxide and 0.05 to 3% by weight ascorbic acid as the initiator system, the nonwoven product exhibiting a low free formaldehyde content after drying and curing of less than 15 ppm;
- wherein the binder is present in an amount which is sufficient to bind the fibers together to form a self-sustaining web.
A textile product comprising a textile substrate coated with an emulsion polymer consisting of at least 50% by weight vinyl acetate:
- 0 to 48% by weight of a comonomer selected from the group consisting of vinyl chloride, vinyl esters of aliphatic carboxylic acids containing 1-20 carbon atoms dialkyl esters of maleic and fumaric acid containing 1-8 carbon atoms in each alkyl group and C1-C8 alkyl acrylates and methacrylates:
- 0 to 30% by weight of ethylene;
- 0 to 4% by weight of an ethylenically unsaturated carboxylic acid;
- 0 to 1% by weight of a polyunsaturated copolymerizable monomer;
- 0 to 5% by weight acrylamide or methacrylamide;
- and a crosslinking monomer, said monomer present in an amount of from 0.5 to 10% said monomer selected from the group consisting of N-methylol acrylamide, N-methylol methacrylamide, N-methylol allyl carbamate, iso-butoxy methyl acrylamide and n-butoxy methyl acrylamide, the emulsion polymer having been polymerized in a medium consisting essentially of water and a stabilizing system consisting of an emulsifier and/or polyvinyl alcohol using 0.05 to 3% by weight of a hydrophobic hydroperoxide and 0.05 to 3% by weight ascorbic acid as the initiator system, the textile product having a free formaldehyde content after drying and curing of less than 15 ppm.
Dependencies are inferred from the claim text.