Vinyl acetate/ethylene and vinyl chloride polymer blends as binders for nonwoven products
This invention is directed to an improvement in binders particularly suited for use in preparing nonwoven products and to the nonwoven products. The improved binders comprise a blend of a vinyl chloride (VCl) polymer emulsion and a self crosslinkable vinyl acetate-ethylene-N-methylolacrylamide (VAE-NMA) polymer emulsion. The blend of the VCl polymer emulsion and the VAE-NMA polymer emulsion can be applied to cellulose and cellulose/synthetic nonwoven substrates and cured in the absence of an acid catalyst to provide a self-sustaining web having excellent wet strength performance.
1. A nonwoven product comprising a nonwoven web of fibers to which is applied a non acid catalyzed binder to form a binder impregnated web, the non acid catalyzed binder comprised of an emulsion blend of a first polymer comprised of emulsion polymerized units of vinyl acetate, ethylene, and N-methylolacrylamide, and a second polymer comprised of emulsion polymerized units of vinyl chloride, ethylene and N-methylolacrylamide or acrylamide or both N-methylolacrylamide and acrylamide, wherein the binder impregnated web is dried sufficiently to bind the fibers together and for a self-sustaining web, and wherein the blend, based on 100 parts by dry weight of total polymer, comprises 2 to 70 parts of the second polymer, less than 10 parts of a third polymer, and the remaining parts consisting of the first polymer.
2. The nonwoven product of claim 1 wherein the blend is comprised of 50 to 80 weight parts of the first polymer and 5 to 50 weight parts of the second polymer, per 100 weight parts of the blend.
3. A nonwoven product comprising a nonwoven web of fibers to which is applied a non acid catalyzed binder to form a binder impregnated web, the non acid catalyzed binder comprised of an emulsion blend of a first polymer comprised of emulsion polymerized units of vinyl acetate, ethylene, and N-methylolacrylamide, and a second polymer comprised of emulsion polymerized units of vinyl chloride alone or vinyl chloride and another monomer, wherein the binder impregnated web is dried sufficiently to bind the fibers together and form a self-sustaining web.
4. The nonwoven product of claim 3 wherein the first polymer comprises 50 to 94 wt % vinyl acetate, 5 to 40 wt % ethylene, and 0.5 to 10 wt % N-methylolacrylamide, based on the total weight of the polymer, and the second polymer comprises 55 to 95 wt % vinyl chloride and 45 to 5 wt % of a monomer selected from the group consisting of a vinyl ester of a carboxylic acid, an unsaturated monocarboxylic acid, an unsaturated polycarboxylic acid, an alkyl vinyl ether, and an olefin, based on the total weight of the polymer.
5. The nonwoven product of claim 3 wherein the first polymer comprises 50 to 94 wt % vinyl acetate, 5 to 40 wt % ethylene, and 0.5 to 10 wt % N-methylolacrylamide, based on the total weight of the polymer, and the second polymer comprises 60 to 90 wt % vinyl chloride, 10 to 30 wt % of another monomer, and 0.5 to 5 wt % of N-methylolacrylamide or acrylamide or a combination of N-methylolacrylamide and acrylamide, based on the total weight of polymer.
6. The nonwoven product of claim 3 wherein the blend, based on 100 parts by dry weight of total polymer, comprises 2 to 70 parts of the second polymer, less than 10 parts of a third polymer, and the remaining parts consisting of the first polymer.
7. The nonwoven product of claim 3 wherein the blend is comprised of 50 to 80 weight parts of the first polymer and 5 to 50 weight parts of the second polymer, per 100 weight parts of the blend.