Paper improver
AssigneeKao Corporation
InventorHaruyuki Satoh
Life of this patent
Estimating the term…
Abstract
The invention provides a paper quality improver for papermaking that allows improvement in the bulky value and the optical properties such as brightness and opacity as well as in the paper strength of a sheet obtained by papermaking a pulp material. The paper quality improver for papermaking is a paper quality improver for papermaking containing a copolymer (A) having a constituent unit derived from at least one nonionic monomer having a solubility parameter of 20.5 (MPa)1/2 or less and a constituent unit derived from at least one anionic or cationic monomer and a surfactant (B) at a certain ratio, the quality improver providing at least one paper quality improving effect of: (i) standard improved bulky value: 0.02 g/cm or more; (ii) standard improved opacity: 1.0 point or more; and (iii) standard improved brightness: 0.5 point or more.
Claims12
A process of producing a pulp sheet, said process comprising:
- adding a paper quality improver for papermaking to pulp in any step before a papermaking step of forming a paper layer while water in a dilute solution of a pulp material is filtered through a wire while moving thereon;
- wherein the paper quality improver for papermaking comprises:
- a copolymer (A) having the following constituent units:
- 10-34 weight % of nonionic unsaturated monomer, wherein said nonionic saturated monomer is tertiary-octyl acrylamide (t-OAAm);
- 17-23 weight % of an anionic or cationic monomer, wherein said anionic or cationic monomer is a quaternary ammonium salt from dimethylaminopropyl acrylamide and methyl chloride (DMAPAA-Q) or a quaternary ammonium salt from dimethylaminoethyl methacrylate and diethyl sulfate (MOEDES);
- and
- 47-67 weight % of a nonionic unsaturated monomer of acrylamide (AAm), and
- a surfactant (B) at an (A)/(B) ratio in the range of 85/15 to 15/85 (weight ratio),
- wherein a mixture of the copolymer (A) and the surfactant (B) is prepared by adding surfactant (B) to an aqueous solution of copolymer (A),
- wherein the paper quality improver provides at least one paper quality improving effect of the following (i), (ii), and (iii):
- (i) standard improved bulky value:
- 0.02 g/cm3 or more;
- (ii) standard improved opacity:
- 1.0 point or more;
- and
- (iii) standard improved brightness:
- 0.5 point or more;
- wherein the surfactant (B) is a water-soluble alcohol alkylene oxide adduct containing an alkylene oxide group having 2 to 4 carbons in an average amount of 5 to less than 150 moles per 1 mole of the alcohol;
- and
- wherein the paper quality improver provides a paper quality improving effect of a standard improved ratio in burst index of -502 or more.
A pulp sheet which is obtained by adding a paper quality improver for papermaking to pulp in any step before a papermaking step of forming a paper layer while water in a dilute solution of a pulp material is filtered through a wire while moving thereon;
- wherein the paper quality improver for papermaking comprises:
- a copolymer (A) having the following constituent units:
- 10-34 weight % of nonionic unsaturated monomer, wherein said nonionic saturated monomer is tertiary-octyl acrylamide (t-OAAm);
- 17-23 weight % of an anionic or cationic monomer, wherein said anionic or cationic monomer is a quaternary ammonium salt from dimethylaminopropyl acrylamide and methyl chloride (DMAPAA-Q) or a quaternary ammonium salt from dimethylaminoethyl methacrylate and diethyl sulfate (MOEDES);
- and
- 47-67 weight % of a nonionic unsaturated monomer of acrylamide (AAm), and
- a surfactant (B) at an (A)/(B) ratio in the range of 85/15 to 15/85 (weight ratio),
- wherein a mixture of the copolymer (A) and the surfactant (B) is prepared by adding surfactant (B) to an aqueous solution of copolymer (A);
- wherein the paper quality improver provides at least one paper quality improving effect of the following (i), (ii), and (iii):
- (i) standard improved bulky value:
- 0.02 g/cm 3 or more;
- (ii) standard improved opacity:
- 1.0 point or more;
- and
- (iii) standard improved brightness:
- 0.5 point or more;
- wherein the surfactant (B) is a water-soluble alcohol alkylene oxide adduct containing an alkylene oxide group having 2 to 4 carbons in an average amount of 5 to less than 150 moles per 1 mole of the alcohol;
- and
- wherein the paper quality improver provides a paper quality improving effect of a standard improved ratio in burst index of -502 or more.
A method of improving paper quality, said method comprising:
- adding a paper quality improver for papermaking to pulp in any step before a papermaking step of forming a paper layer while water in a dilute solution of a pulp material is filtered through a wire while moving thereon;
- wherein the paper quality improver for papermaking comprises:
- a copolymer (A) having the following constituent units:
- 10-34 weight % of nonionic unsaturated monomer, wherein said nonionic saturated monomer is tertiary-octyl acrylamide (t-OAAm);
- 17-23 weight % of an anionic or cationic monomer, wherein said anionic or cationic monomer is a quaternary ammonium salt from dimethylaminopropyl acrylamide and methyl chloride (DMAPAA-Q) or a quaternary ammonium salt from dimethylaminoethyl methacrylate and diethyl sulfate (MOEDES);
- and
- 47-67 weight % of a nonionic unsaturated monomer of acrylamide (AAm), and
- a surfactant (B) at an (A)/(B) ratio in the range of 85/15 to 15/85 (weight ratio),
- wherein a mixture of the copolymer (A) and the surfactant (B) is prepared by adding surfactant (B) to an aqueous solution of copolymer (A),
- wherein the paper quality improver provides at least one paper quality improving effect of the following (i), (ii), and (iii):
- (i) standard improved bulky value:
- 0.02 g/cm 3 or more;
- (ii) standard improved opacity:
- 1.0 point or more;
- and
- (iii) standard improved brightness:
- 0.5 point or more;
- wherein the surfactant (B) is a water-soluble alcohol alkylene oxide adduct containing an alkylene oxide group having 2 to 4 carbons in an average amount of 5 to less than 150 moles per 1 mole of the alcohol;
- and
- wherein the paper quality improver provides a paper quality improving effect of a standard improved ratio in burst index of -502 or more.
Dependencies are inferred from the claim text.