Process for enhancing the freeness of papermaking pulp

• US 5,507,914 A
• Filed: 06/07/1995
• Issued: 04/16/1996
• Est. Priority Date: 08/12/1994
• Status: Expired due to Term

• Current Assignee: Ecolab USA Incorporated (Ecolab, Inc.)
• Original Assignee: Nalco Chemical Company (Ecolab, Inc.)
• Inventors: Didwania, Hanuman P., Sarkar, Jawed M.
• Primary Examiner(s): Chin, Peter
• Application Number:
  US08/484,112
• Time in Patent Office: 314 Days
• Field of Search: 162/158, 162/9, 162/100, 162/168.2, 162/168.3, 162/164.6, 162/183, 162/182, 162/72 B
• US Class Current: 162/100
• CPC Class Codes: D21C 5/005 Treatment of cellulose-containing material with microorganisms or enzymes
• CPC Class Codes: D21H 11/14 Secondary fibres working-up waste paper D21C5/02
• CPC Class Codes: D21H 17/005 Microorganisms or enzymes
• CPC Class Codes: D21H 17/375 Poly(meth)acrylamide
• CPC Class Codes: D21H 17/42 anionic
• CPC Class Codes: D21H 17/455 comprising tertiary amine or being at least partially quaternised
• CPC Class Codes: Y10S 210/928 Paper mill waste, e.g. white water, black liquor treated

Abstract

A process for enhancing the freeness of paper pulp, which comprises the steps of adding to the pulp from about 0.5 to about 2.5 kilograms per ton based on the dry weight of the pulp, of a cellulolytic enzyme at the vertical tank of the papermaking process, allowing the pulp to contact the cellulolytic enzyme for from about 30 minutes to about 60 minutes, adding at least 0.011%, based on the dry weight of the pulp, of a water soluble cationic polymer, adding at least 0.007%, based on the dry weight of the pulp, of a water soluble anionic polymer and forming the thus treated pulp into paper.

Claims

1. A process for enhancing the freeness of pulp in a paper mill machine, the paper machine including a vertical tank, one or more refiners and a machine chest and wherein the pulp flows from the paper machine vertical tank through the refiners and into the machine chest, which comprises the sequential steps of:

a) adding to the pulp from about 0.5 to about 2.5 kilograms per ton based on the dry weight of the pulp, of a cellulolytic enzyme at the vertical tank;

b) allowing the pulp to contact the cellulolytic enzyme for from about 30 minutes to about 60 minutes;

c) adding to the pulp 0.1 to 0.5 kilogram per ton based on dry weight of the pulp of a cellulolytic enzyme before a refiner wherein the pulp is refined,

d) adding at least 0.011% based on the dry weight of the pulp of a water-soluble cationic polymeric coagulant at the machine chest; and

e) adding at least 0.007% based on the dry weight of the pulp of a water soluble anionic polymer selected from the group consisting of acrylamide/acrylic acid and acrylamide/methacrylic acid polymers.

2. The process of claim 1, wherein the water soluble cationic polymer is a copolymer which contains from 20% to 80% by weight of acrylamide.

3. The process of claim 2, wherein the cationic acrylamide copolymer is an acrylamide-diallyldimethyl ammonium chloride copolymer.

4. The process of claim 1, wherein the anionic acrylamide polymer has from about 20 to 95% acrylamide and from about 5 to 80% anionic monomer selected from the group consisting of acrylic acid and methacrylic acid by weight of the polymer.

5. The process of claim 1, wherein the cationic polymers are selected from the group consisting of:

dimethylaminoethylacrylate benzyl chloride quaternary ammonium salts copolymerized with acrylamide, terpolymers of dimethylaminoethylacrylate methyl chloride quaternary ammonium salts, acrylamide and vinyl trimethoxysilane, diallyldimethyl ammonium chloride copolymerized with vinyl trimethoxysilane, copolymers of diallyldimethyl ammonium chloride and dimethylaminoethylacrylate benzyl chloride quaternary ammonium salt, polymeric n-vinylformamide, partially or completely hydrolyzed polymeric n-vinylformamide, copolymers of n-vinylformamide and vinylamine or its hydrochloric salts, polyvinylamine or its hydrochloric salts, partially or completely hydrolyzed polymeric n-vinylformamide methyl chloride quaternary ammonium salts, copolymers of n-vinylformamide and acrylamide, terpolymers of vinylamine, n-vinylformamide and acrylamide, copolymers of acrylamide and vinylamine, terpolymers of acrylamide, n-vinylformamide and vinylamine methyl chloride quaternary ammonium salts, copolymers of acrylamide and vinylamine methyl chloride quaternary ammonium salts, terpolymers of acrylamide, sodium acrylate and n-vinylformamide, terpolymers of acrylamide, sodium acrylate and vinylamine and its acid salts or quats, polymers of acrylamide, sodium acrylate, n-vinylformamide and vinylamine and its acid salts or quats, copolymers of n-vinylformamide and sodium acrylate, copolymers of diallyldimethyl ammonium chloride and n-vinylformamide, terpolymers of diallyldimethyl ammonium chloride, n-vinylformamide and vinylamine and its acid salts or quats, terpolymers of acrylamide, sodium acrylate and vinyl trimethoxysilane and terpolymers of diallyldimethyl ammonium chloride, acrylamide and vinyl trimethoxysilane.