Functionalized vinyl acetate ethylene binders for paper and paperboard coatings

Abstract

A paper product comprising a planar fibrous cellulose substrate, and a coating composition disposed on a surface of said substrate comprising an interpolymer prepared by the emulsion polymerization of (i) one or more vinyl ester monomers; (ii) ethylene; (iii) an unsaturated silane co-monomer; and (iv) one or more emulsion-stabilizing ionic co-monomers comprising one or more of unsaturated, substituted sulfonic acid, one or more of an unsaturated phosphonic acid, or an ester of one of those acids, in the presence of (v) a stabilizing system which comprises one or more anionic and/or nonionic surfactants but less than about 1 pphm of any protective colloid material; and (v) water.

We claim: 
     
         1 . A paper product comprising:
 a planar fibrous cellulose substrate; and   a coating composition disposed on a surface of said substrate comprising an interpolymer prepared by the emulsion polymerization of:
 i) one or more vinyl ester monomers; 
 ii) ethylene; 
 iii) an unsaturated silane co-monomer; and 
 iv) one or more emulsion-stabilizing ionic co-monomers comprising one or more of: (a) an unsaturated, substituted organic sulfonic acid or salt thereof, (b) an unsaturated, organic phosphonic acid or salt thereof, (c) an unsaturated, substituted organic sulfonate or sulfate, or 
 (d) an unsaturated, organic phosphonate or phosphate; 
   in the presence of:
 v) a stabilizing system which comprises one or more anionic and/or nonionic surfactants but less than about 1 pphm of any protective colloid material; and 
 vi) water. 
   
     
     
         2 . The paper product according to  claim 1  wherein the interpolymer comprises from about 0.1 pphm to about 5 pphm of said one or more emulsion-stabilizing ionic co-monomers. 
     
     
         3 . The paper product according to  claim 1  wherein the one or more emulsion-stabilizing ionic co-monomers is selected from the group consisting of acrylamido methyl propane sulfonic acid, styrene sulfonate, and sodium vinyl sulfonate. 
     
     
         4 . The paper product according to  claim 1  wherein the one or more emulsion-stabilizing ionic co-monomers is selected from the group consisting of vinylphosphonic acid, vinyl phosphonate, methacrylic-based phosphonate, phosphate esters of polyethylene glycol monomethacrylate, and (meth)acrylic phosphates. 
     
     
         5 . The paper product according to  claim 1  wherein the emulsion-stabilizing ionic co-monomers further comprise one or more of acrylic acid, methacrylic acid, and the C 4 -C 8  alkyl half esters of maleic acid, maleic anhydride, fumaric acid, and itaconic acid. 
     
     
         6 . The paper product according to  claim 1  further comprising about 2 pphm of acrylic acid co-monomer. 
     
     
         7 . The paper product according to  claim 1  wherein the interpolymer comprises from about 0.1 pphm to about 3 pphm of said unsaturated silane co-monomer. 
     
     
         8 . The paper product according to  claim 1  wherein the vinyl ester monomer is vinyl acetate and the unsaturated silane co-monomer is a vinyl trialkoxy silane. 
     
     
         9 . The paper product according to  claim 8  wherein the unsaturated silane co-monomer is selected from the group consisting of vinyltrimethoxysilane, vinyltriethoxysilane, ω-methacryloxypropyl-trimethoxysilane, vinyl tris(2-methoxyethoxy)silane, vinyltriisopropoxy silane, vinylpropyltriisopropoxy silane, vinylpropyltriisobutoxy silane, vinyltriisobutoxy silane, vinylpentyltri-t-butoxy silane, vinylpropyl-methyldipentoxy silane, and vinylpropyltri-sec-butoxysilane. 
     
     
         10 . The paper product according to  claim 1  wherein the stabilizing system comprises polyoxyethylene condensates. 
     
     
         11 . The paper product according to  claim 1  wherein the stabilizing system comprises anionic surfactants selected from the group consisting of alkyl aryl sulfonates, alkali metal alkyl sulfates, sulfonated alkyl esters and fatty acid soaps. 
     
     
         12 . The paper product according to  claim 1  wherein the interpolymer component is prepared by emulsion polymerizing:
 i) from about 67 to about 99 pphm of the vinyl ester monomer; 
 ii) from about 1.0 to about 30.0 pphm of ethylene; 
 iii) from about 0.1 to about 3.0 pphm of the unsaturated silane co-monomer; and 
 (iv) from about 0.1 to about 1 pphm of at least one of the unsaturated, substituted sulfonic acid, the unsaturated phosphonic acid, or an ester or salt thereof. 
 
     
     
         13 . The paper product according to  claim 1  wherein the coating composition further contains from about 50 wt % to about 90 wt % of filler material selected from the group consisting of calcium carbonate, clay, titanium dioxide, blanc fixe, lithopone, zinc sulfide, polystyrene and combinations thereof. 
     
     
         14 . The paper product according to  claim 13  wherein the coating composition comprises more than about 50 wt % calcium carbonate as the filler material. 
     
     
         15 . The paper product according to  claim 1  wherein the coating composition has a total solids content of from about 50% to about 95% by weight prior to drying. 
     
     
         16 . The paper product according to  claim 1  wherein the emulsion polymerization contains less than about 0.5 pphm of a protective colloid material selected from the group consisting of polyvinyl alcohol, hydroxyethyl cellulose, styrene acrylic acid, styrene maleic acid and carboxymethyl cellulose. 
     
     
         17 . The paper product according to  claim 15  comprising from about 5 wt % to about 20 wt % of said interpolymer. 
     
     
         18 . The paper product according to  claim 1 , further comprising a top coating composition disposed on said coating composition. 
     
     
         19 . The paper product according to  claim 18 , wherein the coating composition is provided in an amount effective to bind the top coating composition to said fibrous cellulose substrate with an IGT dry pick strength at least about 5% greater than a coating composition containing SBR binder, or VAE binder without said co-monomers. 
     
     
         20 . The paper product according to  claim 1 , further comprising at least about 1 wt % polyvinyl alcohol, post-added to the composition as a co-binder. 
     
     
         21 . A process for forming a coated paper product, comprising:
 (a) coating a planar fibrous cellulose substrate with a coating composition to form a wet coated substrate, wherein the coating composition comprises an interpolymer prepared by the emulsion polymerization of:
 i) one or more vinyl ester monomers; 
 ii) ethylene; 
 iii) an unsaturated silane co-monomer; and 
 iv) one or more emulsion-stabilizing ionic co-monomers comprising at least an unsaturated, substituted organic sulfonic acid or salt thereof, an unsaturated, organic phosphonic acid or salt thereof, an unsaturated, substituted organic sulfonate or sulfate, or an unsaturated, organic phosphonate or phosphate; 
   in the presence of:
 vi) a stabilizing system which comprises one or more anionic and/or nonionic surfactants but less than about 1 pphm of any protective colloid material; and 
 vii) water; 
   (b) drying the wet coated substrate to form a dried coated substrate; and   (c) calendering the dried coated substrate to form the coated paper product.