An aqueous copolymer dispersion is obtained by a multi-stage emulsion polymerization process comprising polymerizing in a reaction zone in a first polymerization stage a first monomer composition comprising at least 88 wt % of a viny I ester of a C.sub.1 to C.sub.18 carboxylic acid and up to 12 wt % ethylene to produce a first stage polymer having T.sub.g>20? C.; and polymerizing in the reaction zone, in a second polymerization stage and in the presence of the first stage polymer, a second monomer composition comprising a vinyl ester of a C.sub.1 to C.sub.18 carboxylic acid and a C.sub.2 to C.sub.8 alkyl ester of (meth)acrylic acid to produce a second stage polymer having T.sub.g?20? C. Each of the polymerization stages is conducted in the presence of a stabilizing system comprising at least 0.1 wt % of a protective colloid and at least 0.05 wt % of an ionic surfactant.

In a multi-stage emulsion polymerization process, a first monomer composition comprising from about 60 weight percent to about 95 weight percent of at least one vinyl ester, and from about 5 weight percent to about 40 weight percent ethylene is polymerized in a first stage under ethylene pressure to produce a first stage product having a T.sub.g of less than 20 C. Then, in a second stage, a second monomer composition comprising at least 95 weight percent of a meth(acrylic)ester or a mixture of at least two different (meth)acrylic esters is polymerized in the presence of said first stage product, wherein the (meth)acrylic ester(s) is selected such that the polymer produced by said second monomer composition has a T.sub.g of 5 to 90 C.

In a multi-stage emulsion polymerization process, a first monomer composition comprising from about 60 weight percent to about 95 weight percent of at least one vinyl ester, and from about 5 weight percent to about 40 weight percent ethylene is polymerized in a first stage under ethylene pressure to produce a first stage product having a T.sub.g of less than 20 C. Then, in a second stage, a second monomer composition comprising at least 95 weight percent of a meth(acrylic)ester or a mixture of at least two different (meth)acrylic esters is polymerized in the presence of said first stage product, wherein the (meth)acrylic ester(s) is selected such that the polymer produced by said second monomer composition has a T.sub.g of 5 to 90 C.

In a multi-stage emulsion polymerization process, a first monomer composition comprising from about 60 weight percent to about 95 weight percent of at least one vinyl ester, and from about 5 weight percent to about 40 weight percent ethylene is polymerized in a first stage under ethylene pressure to produce a first stage product having a T.sub.g of less than 20 C. Then, in a second stage, a second monomer composition comprising at least 95 weight percent of a meth(acrylic)ester or a mixture of at least two different (meth)acrylic esters is polymerized in the presence of said first stage product, wherein the (meth)acrylic ester(s) is selected such that the polymer produced by said second monomer composition has a T.sub.g of 5 to 90 C.

The present invention provides a method for crosslinking an acrylic emulsion with a (meth)acrylate monomer or a (meth)acrylate oligomer including adding a base acrylic emulsion to a vessel, adding at least one (meth)acrylate crosslinker to the vessel, incorporating the at least one (meth)acrylate crosslinker into the base acrylic emulsion to create a two-phase system including water and a phase including crosslinkers of the at least one (meth)acrylate crosslinker inside acrylic emulsion particles of the base acrylic emulsion, applying the two-phase system to a surface, and curing the two-phase system to create a final system including a film and crosslinked crosslinkers.

The present invention provides a method for crosslinking an acrylic emulsion with a (meth)acrylate monomer or a (meth)acrylate oligomer including adding a base acrylic emulsion to a vessel, adding at least one (meth)acrylate crosslinker to the vessel, incorporating the at least one (meth)acrylate crosslinker into the base acrylic emulsion to create a two-phase system including water and a phase including crosslinkers of the at least one (meth)acrylate crosslinker inside acrylic emulsion particles of the base acrylic emulsion, applying the two-phase system to a surface, and curing the two-phase system to create a final system including a film and crosslinked crosslinkers.

The present invention provides a method for crosslinking an acrylic emulsion with a (meth)acrylate monomer or a (meth)acrylate oligomer including adding a base acrylic emulsion to a vessel, adding at least one (meth)acrylate crosslinker to the vessel, incorporating the at least one (meth)acrylate crosslinker into the base acrylic emulsion to create a two-phase system including water and a phase including crosslinkers of the at least one (meth)acrylate crosslinker inside acrylic emulsion particles of the base acrylic emulsion, applying the two-phase system to a surface, and curing the two-phase system to create a final system including a film and crosslinked crosslinkers.

The invention relates to a method for treating an aqueous suspension of solid particles, wherein at least one water-soluble polymer is added to the suspension, and wherein said polymer is obtained by polymerizing at least a non-ionic monomer, optionally at least one anionic and/or at least one cationic monomer, in the presence of a multifunctional free radical transfer agent. This method is particularly useful for the treatment of mineral tailings and especially for tailings resulting from oil sand extraction.

An object of the present invention is to develop an NBR composition excellent in an adhesive strength with a saponified ethylene-vinyl acetate copolymer layer, and a laminate excellent in an adhesive strength of an NBR layer with a saponified ethylene-vinyl acetate copolymer layer; and the present invention relates to an acrylonitrile-butadiene rubber composition comprising an acrylonitrile-butadiene rubber and a silane-modified ethylene-vinyl acetate copolymer of 0 to 50 parts by mass with respect to 100 parts by mass of the acrylonitrile-butadiene rubber, and a laminate comprising an acrylonitrile-butadiene rubber layer comprising the composition and the saponified ethylene-vinyl acetate copolymer layer through an ethylene-vinyl acetate copolymer layer.

An object of the present invention is to develop an NBR composition excellent in an adhesive strength with a saponified ethylene-vinyl acetate copolymer layer, and a laminate excellent in an adhesive strength of an NBR layer with a saponified ethylene-vinyl acetate copolymer layer; and the present invention relates to an acrylonitrile-butadiene rubber composition comprising an acrylonitrile-butadiene rubber and a silane-modified ethylene-vinyl acetate copolymer of 0 to 50 parts by mass with respect to 100 parts by mass of the acrylonitrile-butadiene rubber, and a laminate comprising an acrylonitrile-butadiene rubber layer comprising the composition and the saponified ethylene-vinyl acetate copolymer layer through an ethylene-vinyl acetate copolymer layer.