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Aqueous based pressure sensitive adhesives having improved shear properties are prepared from a latex of a monomer composition selected from the group: (a) (i) from about 60 to 99.5 weight percent of an ester of acrylic or methacrylic acid; and (ii) from about 0.5 to about 40 weight percent of

Aqueous based pressure sensitive adhesives having improved shear properties are prepared from a latex of a monomer composition selected from the group: (a) (i) from about 60 to 99.5 weight percent of an ester of acrylic or methacrylic acid; and (ii) from about 0.5 to about 40 weight percent of a C 3-9 ethylenically unsaturated carboxylic acid; (b) (i) from about 40 to 99 weight percent of a C 4-8 conjugated diolefin; (ii) optionally up to about 60 weight percent of a vinyl aromatic monomer; (iii) from about 0.5 to about 40 weight percent of a C 3-9 ethylenically unsaturated carboxylic acid; and (c) (i) from about 1 to 40 weight percent of a C 2-4 monoolefin; (ii) from about 60 to 99.5 weight percent of a vinyl ester; and (iii) from about 0.5 to 40 weight percent of a C 3-9 ethylenically unsaturated carboxylic acid; said latex having been neutralized to a pH of equal to or greater than about 6 with an alkali metal hydroxide or salt. The polymer may optionally have a molecular weight distribution so that from about 20 to 55 weight percent of it has a molecular weight greater than 320,000. The adhesive may optionally include tackifiers. The resulting adhesives may be used in the manufacture of tapes and labels.

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1. An aqueous based pressure sensitive adhesive having improved shear properties comprising a latex of a polymer having a Tg less than about 0° C., formed by emulsion polymerizing a monomeric mixture selected from the group comprising: (a) (i) from about 60-99.5 weight percent of a C 1-8 alkyl o

1. An aqueous based pressure sensitive adhesive having improved shear properties comprising a latex of a polymer having a Tg less than about 0° C., formed by emulsion polymerizing a monomeric mixture selected from the group comprising: (a) (i) from about 60-99.5 weight percent of a C 1-8 alkyl or alkanol ester of acrylic or methacrylic acid; or a mixture thereof and (ii) from 0.5 to about 40 weight percent of a C 3-9 ethylenically unsaturated acid; and (iii) from 0 up to about 5 weight percent of an amide of a C 3-9 ethylenically unsaturated acid which amide may be unsubstituted or substituted at the nitrogen atom by a C 1-8 alkyl or alkanol radical; a C 3-9 ethylenically unsaturated aldehyde; or an anhydride of a C 4-8 ethylenically unsaturated dicarboxylic acid; or a mixture thereof; (b) (i) from about 0 to about 60 weight percent of a vinyl aromatic monomer which may be unsubstituted or substituted by a C 1-4 alkyl radical or a chlorine or bromine atom; (ii) from 40 to 99 weight percent of a mixture comprising 100 to 50 weight percent of a C 4-8 conjugated diolefin and 0 to 50 weight percent of a C 1-8 alkyl or alkanol, or a C 2-8 alkenyl or alkenol ester of a C 3-9 ethylenically unsaturated acid; (iii) from about 0.5 to 10 weight percent of a C 3-9 ethylenically unsaturated acid; and (iv) from 0 up to about 5 weight percent of an amide of a C 3-9 ethylenically unsaturated acid which amide may be unsubstituted or substituted at the nitrogen atom by a C 1-8 alkyl or alkanol radical; a C 3-9 ethylenically unsaturated aldehyde; or an anhydride of a C 4-8 ethylenically unsaturated dicarboxylic acid; or a mixture thereof; and (c) (i) from about 1 to about 40 weight percent of a C 2-4 monoolefin monomer; (ii) from about 60 to 99.5 weight percent of a C 1-8 alkyl or alkanol ester of a C 3-12 ethylenically unsaturated carboxylic acid or a C 2-8 alkenyl or alkenol ester of a C 1-12 saturated carboxylic acid or a mixture thereof; and (iii) from about 0.5 to 10 weight percent of a C 3-9 ethylenically unsaturated acid; and (iv) from 0 up to about 5 weight percent of an amide of a C 3--9 ethylenically unsaturated acid which amide may be unsubstituted or substituted at the nitrogen atom by a C 1-8 alkyl or alkanol radical; a C 3-9 ethylenically unsaturated aldehyde; or an anhydride of a C 4-8 ethylenically unsaturated dicarboxylic acid or a mixture thereof; which has been adjusted to a pH of equal to or greater than about 6 with an agent selected from hydroxides and salts of lithium, sodium, potassium and a mixture thereof. 2. An adhesive according to claim 1 wherein the latex is adjusted to a pH of from 6 to about 8.5, following polymerization, with an agent selected from hydroxides and salts of lithium, sodium, potassium and a mixture thereof. 3. An adhesive according to claim 2 wherein said polymer is formed by polymerizing a monomeric mixture comprising: (i) from about 5 to 15 weight % of acrylic acid, methacrylic acid or a mixture thereof; (ii) from about 60-90 weight % of a C 1-8 alkyl or alkanol ester of acrylic or methacrylic acid; and (iii) from 0 to about 10 weight % of a C 3-9 ethylenically unsaturated acid other than acrylic or methacrylic acid; and (iv) from 0 up to about 5 weight % of an amide of a C 3-8 ethylenically unsaturated acid which amide may be unsubstituted or substituted at the nitrogen atom by a C 1-8 alkyl or alkanol radical; a C 3-9 ethylenically unsaturated aldehyde; or an anhydride of a C 4-8 ethylenically unsaturated dicarboxylic acid, or a mixture thereof. 4. An adhesive according to claim 2 wherein said polymer is formed by polymerizing a monomeric mixture comprising: (i) from 0 to 60 weight % of a vinyl aromatic monomer which may be unsubstituted or substituted by a C 1-4 alkyl radical or a chlorine or bromine atom; (ii) from about 40 to 99.5 weight % of a C 4-8 conjugated diolefin; (iii) from about 0.5 to 10 weight % of a C 3-9 ethylenically unsaturated acid; and (iv) from 0 up to about 5 weight % of an amide of a C 3-9 ethylenically unsaturated acid which amide may be unsubstituted or substituted at the nitrogen atom by a C 1-8 alkyl or alkanol radical; a C 3-9 ethylenically unsaturated aldehyde; or an anhydride of a C 4-8 ethylenically unsaturated dicarboxylic acid; or a mixture thereof. 5. An adhesive according to claim 2 wherein said polymer is formed by polymerizing a monomeric mixture comprising: (i) from about 0 to about 15 weight percent of a C 2-4 monoolefin monomer; (ii) from about 60 to 99.5 weight percent of a C 1-8 alkyl or alkanol ester of a C 3-12 ethylenically unsaturated carboxylic acid or a C 2-8 alkenyl or alkenol ester of a C 1-12 saturated carboxylic acid or a mixture thereof; and (iii) from about 0.5 to 10 weight percent of a C 3-9 ethylenically unsaturated acid; and (iv) from 0 up to about 5 weight percent of an amide of a C 3-9 ethylenically unsaturated acid which amide may be unsubstituted or substituted at the nitrogen atom by a C 1-8 alkyl or alkanol radical; a C 3-9 ethylenically unsaturated aldehyde; or an anhydride of a C 4-8 ethylenically unsaturated dicarboxylic acid; or a mixture thereof. 6. An adhesive according to claim 4 wherein in said monomeric mixture said C 3-9 ethylenically unsaturated acid is present in an amount of from 0.5 to 5 weight % and said amide is present in an amount from 0 to 5 weight %. 7. An adhesive according to claim 6 wherein said ethylenically unsaturated acid is present in an amount from about 1 to about 3 weight %. 8. An adhesive according to claim 7 wherein said monomeric mixture contains from about 15 to 50 weight % of a vinyl aromatic monomer selected from styrene, p-methyl styrene, α-methyl styrene, chlorostyrene and a mixture thereof. 9. An adhesive according to claim 8 wherein said monomeric mixture contains from about 85 to 50 weight % of a conjugated diolefin selected from butadiene, isoprene, and a mixture thereof. 10. An adhesive according to claim 9 wherein the acid is selected from the group acrylic acid, methacrylic acid, fumaric acid, itaconic acid, maleic acid, cinnamic acid, and a mixture thereof. 11. An adhesive according to claim 10 wherein said polymer has a molecular weight distribution so that from about 20 to 55 weight % of the polymer has a molecular weight greater than 320,000. 12. An adhesive according to claim 10 wherein said amide is present in an amount from about 1 to 3 weight % and is selected from acrylamide, methacrylamide, N-methylolacrylamide, and a mixture thereof. 13. An adhesive according to claim 12 wherein said polymer has a molecular weight distribution so that from about 20 to 55 weight % has a molecular weight greater than 320,000. 14. An adhesive according to claim 4 wherein in said monomeric mixture said acid is present in an amount from 0.5 to about 5 weight % and is selected from acrylic acid, methacrylic acid, fumaric acid, maleic acid, itaconic acid, and cinnamic acid, and said aldehyde is present in an amount from 0.5 to 5 weight % and is selected from acrolein, methacrolein and cinnamaldehyde. 15. An adhesive according to claim 14 wherein said polymer has a molecular weight distribution so that from about 20 to 55 weight % has a molecular weight greater than 320,000. 16. An adhesive according to claim 2 wherein the pH of the latex is adjusted to about 7 with an hydroxide of sodium, potassium or lithium, and then subsequently raised from a pH of about 8 to 10 with ammonium hydroxide, or an organic base. 17. An adhesive according to claim 11 wherein the pH of the latex is adjusted to about 7 with an hydroxide of sodium, potassium or lithium, and then subsequently raised from a pH of about 8 to 10 with ammonium hydroxide, or an organic base. 18. An adhesive according to claim 3 wherein in said monomeric mixture said C 3-9 ethylenically unsaturated acid other than acrylic or methacrylic acid is present in an amount of from 0.5 to 5 weight % and said amide is present in an amount from 0 to 5 weight %. 19. An adhesive according to claim 5 wherein in said monomeric mixture said C 3-9 ethylenically unsaturated acid is present in an amount of from 0.5 to 5 weight % and said amide is present in an amount from 0 to 5 weight %. 20. An adhesive according to claim 11 further containing a tackifier in an amount from about 15 to about 100 parts by weight per 100 parts by weight of polymer which is selected from: (a) rosin or a hydrogenated rosin ester which has a ring and ball softening temperature from about 25° to 115° C.; (b) a synthetic hydrocarbon tackifier resin having a ring and ball softening temperature from about 10° to about 100° C. manufactured from a C 9 aromatic monomer, or a mixture of tackifiers manufactured from a C 9 aromatic monomer, and a C 5 aliphatic monomer; and (c) an acrylic resin selection from polymers of one or more of acrylic acid which is unsubstituted or substituted by a C 1-4 alkyl or alkoxy radical, or C 1-6 alkyl esters thereof. 21. An adhesive according to claim 13 further containing a tackifier in an amount from about 15 to about 100 parts by weight per 100 parts by weight of polymer which is selected from: (a) rosin or a hydrogenated rosin ester which has a ring and ball softening temperature from about 25° to 115° C.; (b) a synthetic hydrocarbon tackifier resin having a ring and ball softening temperature from about 10° to about 100° C. manufactured from a C 9 aromatic monomer, or a mixture of tackifiers manufactured from a C 9 aromatic monomer and a C 5 aliphatic monomer; and (c) an acrylic resin selected from polymers of one or more of acrylic acid which is unsubstituted or substituted by a C 1-4 alkyl or alkoxy radical, or C 1-6 alkyl esters thereof. 22. An adhesive according to claim 18 wherein said polymer has a molecular weight distribution so that from about 20 to 55 weight % has a molecular weight greater than 320,000. 23. An adhesive according to claim 19 wherein said polymer has a molecular weight distribution so that from about 20 to 55 weight % has a molecular weight greater than 320,000. 24. A sheet substrate coated with an adhesive composition according to claim 3. 25. A sheet substrate coated with an adhesive composition according to claim 4. 26. A sheet substrate coated with an adhesive composition according to claim 5. 27. A sheet substrate coated with an adhesive composition according to claim 11. 28. A sheet substrate coated with an adhesive composition according to claim 13. 29. A sheet substrate coated with an adhesive composition according to claim 22. 30. A sheet substrate coated with an adhesive composition according to claim 23.