Method for making an aqueous emulsion polymer

Abstract

A method for making a polymer includes adding a first portion of a colloidal stabilizer to an aqueous medium, adding a monomer mixture, said monomer mixture including a monomer charge and a second portion of colloidal stabilizer and said monomer charge including from about 40 parts by weight to about 70 parts by weight of a vinyl ester monomer per 100 parts by weight monomer charge and from about 30 parts by weight to about 60 parts by weight of a (C.sub.1 -C.sub.12)alkyl (meth)acrylate monomer per 100 parts by weight monomer charge, to the aqueous medium and polymerizing the monomers to form an emulsion of the polymer in the aqueous medium.

Description

Claims

1. A method for making a polymer, comprising:

preparing two mixtures:

a first mixture prepared by adding a first portion of colloidal stabilizer to an aqueous medium;

a second mixture prepared by adding a monomer mixture, said monomer mixture comprising a monomer charge and a second portion of colloidal stabilizer, said monomer charge consisting of from about 40 parts by weight to about 70 parts by weight of a vinyl ester monomer per 100 parts by weight monomer charge, from about 30 parts by weight to about 60 parts by weight of a (C.sub.1 -C.sub.12)alkyl (meth)acrylate monomer per 100 parts by weight monomer charge, wherein the combined first and second portions of colloidal stabilizer comprise from about 0.05 parts by weight to about 10 parts by weight colloidal stabilizer per 100 parts by weight monomer charge and wherein the first portion of colloidal stabilizer comprises from about 1 part by weight to about 60 parts by weight colloidal stabilizer per 100 parts by weight of the combined amount of the first and second portions of colloidal stabilizer;

admixing the first and second mixtures; wherein the first and second portion of colloidal stabilizer are independently selected from the group consisting of poly(vinyl alcohol), partially hydrolyzed poly(vinyl alcohol), fully hydrolyzed poly(vinyl alcohol), and mixtures thereof; and

polymerizing the monomers of the monomer charge to form an emulsion polymer, said polymer having a glass transition temperature of less than or equal to about +15.degree. C., in the aqueous medium;

further provided that a chain transfer agent is not employed in the method for making the polymer;

such that the polymer provides an adhesive with a hot shear strength of greater than 4 hours.

2. The method of claim 1, wherein the vinyl ester monomer is selected from the group consisting of vinyl acetate, vinyl propionate, vinyl neononanoate, vinyl neodecanoate, vinyl 2-ethylhexanoate, vinyl pivalate, vinyl versatate and mixtures thereof.

3. The method of claim 1, wherein the (C.sub.1-C.sub.12)alkyl (meth)acrylate monomer is selected from the group consisting of ethyl acrylate, butyl acrylate, 2-ethylhexyl acrylate, lauryl acrylate, methyl methacrylate, ethyl methacrylate, butyl methacrylate, isodecyl methacrylate, lauryl methacrylate and mixtures thereof.

4. An adhesive composition comprising an aqueous dispersion of a polymer made by the process of claim 1.

5. The method of claim 1, wherein the polymer has a glass transition temperature of from about -35.degree. C. to about 0.degree. C.

6. A method for making a polymer, comprising:

preparing two mixtures:

a first mixture prepared by adding a first portion of colloidal stabilizer to an aqueous medium;

a second mixture prepared by adding a monomer mixture, said monomer mixture comprising a monomer charge and a second portion of colloidal stabilizer, said monomer charge consisting of from about 40 parts by weight to about 70 parts by weight of a vinyl ester monomer per 100 parts by weight monomer charge, from about 30 parts by weight to about 60 parts by weight of a (C.sub.1 -C.sub.12)alkyl (meth)acrylate monomer per 100 parts by weight monomer charge and from about 0.5 parts by weight to about 2 parts by weight of a monoethylenically unsaturated carboxylic acid monomer per 100 parts by weight monomer charge, wherein the combined first and second portions of colloidal stabilizer comprise from about 0.05 parts by weight to about 10 parts by weight colloidal stabilizer per 100 parts by weight monomer charge and wherein the first portion of colloidal stabilizer comprises from about 1 part by weight to about 60 parts by weight colloidal stabilizer per 100 parts by weight of the combined amount of the first and second portions of colloidal stabilizer;

admixing the first and second mixtures; wherein the first and second portion of colloidal stabilizer are independently selected from the group consisting of poly(vinyl alcohol), partially hydrolyzed poly(vinyl alcohol), fully hydrolyzed poly(vinyl alcohol), and mixtures thereof; and

polymerizing the monomers of the monomer charge to form an emulsion polymer, said polymer having a glass transition temperature of less than or equal to about +15.degree. C., in the aqueous medium;

further provided that a chain transfer agent is not employed in the method for making the polymer;

such that the polymer provides an adhesive with a hot shear strength of greater than 4 hours.

7. The method of claim 6, wherein the vinyl ester monomer is selected from the group consisting of vinyl acetate, vinyl propionate, vinyl neononanoate, vinyl neodecanoate, vinyl 2-ethylhexanoate, vinyl pivalate, vinyl versatate and mixtures thereof.

8. The method of claim 6, wherein the (C.sub.1 -C.sub.12) alkyl(meth)acrylate monomer is selected from the group consisting of ethyl acrylate, butyl acrylate, 2-ethylhexyl acrylate, lauryl acrylate, methyl methacrylate, ethyl methacrylate, butyl methacrylate, isodecyl methacrylate, lauryl methacrylate and mixtures thereof.

9. An adhesive composition comprising an aqueous dispersion of a polymer made from the process of claim 6.

10. The method of claim 6, wherein the polymer has a glass transition temperature of from about -35.degree. C. to about 0.degree. C.

11. The method of claim 6, wherein the monoethylenically unsaturated carboxylic acid monomer is acrylic acid.