Stable, pumpable, solvent-free colloidal polyampholyte latices, their preparation and use in paper

Claim 2

A stable, pumpable, solvent-free polyampholyte latex, characterized by a solids content of about 10 to 40% by weight and a RVF Brookfield bulk viscosity of up to 20,000 centipoises at 25° C. and 20 RPM, which comprises water and an amphoteric copolymer colloidally dispersed therein, said copolymer characterized by a charge density of 15 to 60 mole % and a cationic to anionic molar charge ratio between about 0.33 and 6 and derived from: a. at least one cationic monomer present in a total amount from about 10 to 30 mole %; b. at least one anionic monomer present in a total amount from about 5 to 30 mole %; c. at least one hydrophobic monomer present in a total amount from about 15 to 35 mole %; and d. at least one non-ionic hydrophilic monomer present in a total amount from about 5 to 70 mole %, said monomer percentages totaling 100 mole %.

Claim 3

The latex of claim 1, wherein said latex has a solids content of about 15-25% and a bulk viscosity of about 1500 to 5000 centipoises.

Claim 4

The latex of claim 1, wherein said copolymer is characterized by a charge density of about 20 to 55 mole % and a charge ratio between about 0.5 and 3; said cationic monomer is dimethyldiallylammonium chloride, diethyldiallylammonium chloride, 2-acrylamido-2-methylpropyltrimethylammonium chloride, 2-methacryloxy-2-ethyltrimethylammonium chloride, 2-methacryloxy-2-hydroxypropyltrimethylammonium methosulfate, trimethylmethacryloxyethylammonium methosulfate, acrylamidopropyltrimethylammonium chloride, or vinylbenzyltrimethylammonium chloride, said anionic monomer is acrylic acid, methacrylic acid, 2-sulfoethyl methacrylate, sodium styrene sulfonate, or 2-acrylamido-2-methylpropane sulfonic acid; said hydrophobic monomer is a C 1 -C 12 -alkyl acrylate, a C 1 -C 12 -alkyl methacrylate, styrene, or a C 4 -C 8 -alkyl N-substituted acrylamide; and said non-ionic hydrophilic monomer is acrylamide, N,N-dimethyl acrylamide, hydroxyethyl acrylate, hydroxypropyl acrylate, hydroxyethyl methacrylate, or hydroxypropyl methacrylate.

Claim 5

The latex of claim 1, wherein said latex has a solids content of about 15 to 30% by weight and a bulk viscosity of about 25 to 13,000 centipoises and said copolymer is derived from 15-20 mole % dimethyldiallylammonium chloride, 6-16 mole % acrylic acid, 20-25 mole % n-butyl acrylate, and 39-56 mole % acrylamide; or from 30 mole % dimethyldiallylammonium chloride, 24 mole % acrylic acid, 15 mole % t-octyl acrylamide, and 31 mole % acrylamide; or from 30 mole % dimethyldiallylammonium chloride, 12 mole % acrylic acid, 18 mole % methyl acrylate, and 40 mole % hydroxypropyl acrylate; or from 30 mole % dimethyldiallylammonium chloride, 24 mole % acrylic acid, 31 mole % methyl acrylate, and 15 mole % acrylamide; or from 10 mole % trimethylmethacryloxyethylammonium methosulfate, 20 mole % sulfatoethyl methacrylate, 35 mole % n-butyl acrylate, and 35 mole % acrylamide.

Claim 6

The latex of claim 1, wherein the copolymer derived from dimethyldiallylammonium chloride, acrylic acid, n-butyl acrylate, and acrylamide is characterized by a charge density of about 24 to 36 mole % and a charge ratio between 1.25 and 3.

Claim 7

The process for preparing the latex of claim 1, which comprises the step of polymerizing said monomers at 30° to 100° C. in the presence of water and a free-radical initiator and optionally a chelating agent.

Claim 8

The process for preparing the latex of claim 4, which comprises the step of polymerizing said monomrs at 50° to 75° C. in the presence of water and, as a free radical initiator, ammonium persulfate or a mixture of sodium formaldehyde sulfoxylate and t-butyl hydroperoxide.

Claim 9

A stable, pumpable, solvent-free polyampholyte latex comprising water and an amphoteric copolymer colloidally dispersed therein, said latex characterized by a solids content of about 10 to 40% by weight and a RVF Brookfield bulk viscosity of up to 20,000 centipoises at 25° C. and at 20 RPM and said copolymer characterized by a total charge density of about 15 to 60 mole % and a cationic to anionic molar charge ratio between about 0.33 and 6, said latex prepared by a process comprising the step of polymerizing at 30° to 100° C., in the presence of water and a free radical initiator and optionally a chelating agent, about 10 to 30 mole % of at least one cationic monomer, about 5 to 30 mole % of at least one anionic monomer, about 15 to 35 mole % of at least one hydrophobic monomer, and about 5 to 70 mole % of at least one non-ionic hydrophilic monomer, said monomer percentages totaling 100 mole %.

Claim 10

A stable, pumpable, solvent-free polyampholyte latex comprising water and an amphoteric copolymer colloidally dispersed therein, said latex characterized by a solids content of about 10 to 40% by weight and a RVF Brookfield bulk viscosity of up to 20,000 centipoises at 25° C. and at 20 RPM and said copolymer characterized by a total charge density of about 15 to 60 mole % and a cationic to anionic molar charge ratio between about 0.33 and 6, said latex prepared by a process comprising the step of polymerizing at 30° to 100° C., in the presence of water and a free radical initiator and optionally a chelating agent, about 10 to 30 mole % of at least one cationic monomer, about 5 to 30 mole % of at least one anionic monomer, about 15 to 35 mole % of at least one hydrophobic monomer, and about 5 to 70 mole % of at least one non-ionic hydrophilic monomer, said monomer percentages totaling 100 mole %.

Claim 11

The latex of claim 8, wherein said copolymer is characterized by a charge density of about 20 to 55 mole % and a charge ratio between 0.5 and 3; said cationic monomer is dimethyldiallylammonium chloride, diethyldiallylammonium chloride, 2-acrylamido-2-methylpropyltrimethylammonium chloride, 2-methacryloxy-2-ethyltrimethylammonium chloride, 2-methacryloxy-2-hydroxypropyltrimethylammonium methosulfate, trimethylmethacryloxyethylammonium methosulfate, acrylamidopropyltrimethylammonium chloride, or vinylbenzyltrimethylammonium chloride, said anionic monomer is acrylic acid, methacrylic acid, 2-sulfoethyl methacrylate, sodium styrene sulfonate, or 2-acrylamido-2-methylpropane sulfonic acid; said hydrophobic monomer is a C 1 -C 12 -alkyl acrylate, a C 1 -C 12 -alkyl methacrylate, styrene, or a C 4 -C 8 -alkyl N-substituted acrylamide; and said non-ionic hydrophilic monomer is acrylamide, N,N-dimethyl acrylamide, hydroxyethyl acrylate, hydroxypropyl acrylate, hydroxyethyl methacrylate, or hydroxypropyl methacrylate.

Claim 12

The latex of claim 8, wherein said latex has a solids content of about 15 to 30% by weight and a bulk viscosity of about 25 to 13,000 centipoises at 25° C. and said copolymer is derived from 15-20 mole % dimethyldiallylammonium chloride, 6-16 mole % acrylic acid, 20-25 mole % n-butyl acrylate, and 39-56 mole % acrylamide; or from 30 mole % dimethyldiallylammonium chloride, 24 mole % acrylic acid, 15 mole % t-octyl acrylamide, and 31 mole % acrylamide; or from 30 mole % dimethyldiallylammonium chloride, 12 mole % acrylic acid, 18 mole % methyl acrylate, and 40 mole % hydroxypropyl acrylate; or from 30 mole % dimethyldiallylammonium chloride, 24 mole % acrylic acid, 31 mole % methyl acrylate, and 15 mole % acrylamide; or from 10 mole % trimethylmethacryloxyethylammonium methosulfate, 20 mole % sulfatoethyl methacrylate, 35 mole % n-butyl acrylate, and 35 mole % acrylamide; and said polymerization step is carried out at 50°-75° C. in the presence of ammonium persulfate or a mixture of sodium formaldehyde sulfoxylate and t-butyl peroxide as a free radical initiator.

Claim 13

In a method for making paper, the step which comprises adding, as a paper-making aid, to the paper-making pulp at any stage prior to forming a web, a stable, pumpable, solvent-free polyampholyte latex characterized, before any optional dilution thereof, by a solids content of about 10 to 40% by weight and a RVF Brookfield bulk viscosity of up to 20,000 centipoises at 25° C. and 20 RPM, said latex comprising water and an amphoteric copolymer colloidally dispersed therein, said copolymer characterized by a total charge density of 15 to 60 mole % and a cationic to anionic molar charge ratio between about 0.33 and 6 and derived from at least one cationic monomer present in a total amount from about 10 to 30 mole %, at least one anionic monomer present in a total amount from about 5 to 30 mole %, at least one hydrophobic monomer present in a total amount from about 15 to 35 mole %, and at least one non-ionic hydrophilic monomer present in a total amount from about 5 to 70 mole %, said monomer percentages totaling 100 mole %; said latex being added in an amount sufficient to make said paper containing from about 0.01 to 1% by weight of said copolymer, based on said dry pulp.

Claim 14

In a method for making paper, the step which comprises adding, as a paper-making aid, to the paper-making pulp at any stage prior to forming a web, a stable, pumpable, solvent-free polyampholyte latex characterized, before any optional dilution thereof, by a solids content of about 10 to 40% by weight and a RVF Brookfield bulk viscosity of up to 20,000 centipoises at 25° C. and 20 RPM, said latex comprising water and an amphoteric copolymer colloidally dispersed therein, said copolymer characterized by a total charge density of 15 to 60 mole % and a cationic to anionic molar charge ratio between about 0.33 and 6 and derived from at least one cationic monomer present in a total amount from about 10 to 30 mole %, at least one anionic monomer present in a total amount from about 5 to 30 mole %, at least one hydrophobic monomer present in a total amount from about 15 to 35 mole %, and at least one non-ionic hydrophilic monomer present in a total amount from about 5 to 70 mole %, said monomer percentages totaling 100 mole %; said latex being added in an amount sufficient to make said paper containing from about 0.01 to 1% by weight of said copolymer, based on said dry pulp.

Claim 15

In the method of claim 11, wherein said paper-making aid is a pigment retention aid, said latex is added in an amount sufficient to make said paper containing from about 0.03 to 0.1% by weight of said copolymer, based on said dry pulp.

Claim 16

In the method of claim 11, wherein said paper-making aid is a drainage aid, said latex is added in an amount sufficient to make said paper containing from about 0.1 to 0.5% by weight of said copolymer, based on said dry pulp.

Claim 17

In the method of claim 12 or 13, wherein said copolymer is characterized by a charge density of about 20 to 55 mole % and a charge ratio between about 0.5 and 3; said cationic monomer is dimethyldiallylammonium chloride, diethyldiallylammonium chloride, 2-acrylamido-2-methylpropyltrimethylammonium chloride, 2-methacryloxy-2-ethyltrimethylammonium chloride, 2-methacryloxy-2-hydroxypropyltrimethylammonium methosulfate, trimethylmethacryloxyethylammonium methosulfate, acrylamidopropyltrimethylammonium chloride, or vinylbenzyltrimethylammonium chloride, said anionic monomer is acrylic acid, methacrylic acid, 2-sulfoethyl methacrylate, sodium styrene sulfonate, or 2-acrylamido-2-methylpropane sulfonic acid, said hydrophobic monomer is a C 1 -C 12 -alkyl N-substituted acrylamide, hydroxyethyl acrylate, hydroxypropyl acrylate, hydroxyethyl methacrylate, or hydroxypropyl methacrylate.

Claim 18

In the method of claim 12 or 13, wherein said latex is characterized by a solids content of 15-30% by weight and a bulk viscosity of 25 to 13,000 centipoises at 25° C. and said copolymer is derived from 15-20 mole % dimethyldiallylammonium chloride, 6-16 mole % acrylic acid, 20-25 mole % n-butyl acrylate, and 39-56 mole % acrylamide; or from 30 mole % dimethyldiallylammonium chloride, 24 mole % acrylic acid, 15 mole % t-octyl acrylamide, and 31 mole % acrylamide; or from 30 mole % dimethyldiallylammonium chloride, 12 mole % acrylic acid, 18 mole % methyl acrylate, and 40 mole % hydroxypropyl acrylate; or from 30 mole % dimethyldiallylammonium chloride, 24 mole % acrylic acid, 31 mole % methyl acrylate, and 15 mole % acrylamide; or from 10 mole % trimethylmethacryloxyethylammonium methosulfate, 20 mole % sulfatoethyl methacrylate, 35 mole % n-butyl acrylate, and 35 mole % acrylamide.

Claim 19

In the method of claim 15, wherein said copolymer derived from dimethyldiallylammonium chloride, acrylic acid, n-butyl acrylate, and acrylamide is characterized by a charge density of about 24 to 36 mole % and a charge ratio between about 1.25 and 3.