US2872313A - Pulping of paper broke containing wet-strength resins - Google Patents

Pulping of paper broke containing wet-strength resins Download PDF

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US2872313A
US2872313A US53325955A US2872313A US 2872313 A US2872313 A US 2872313A US 53325955 A US53325955 A US 53325955A US 2872313 A US2872313 A US 2872313A
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pulping
paper
broke
resin
strength
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Ronald R House
Jen Yun
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Wyeth Holdings LLC
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American Cyanamid Co
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    • DTEXTILES; PAPER
    • D21PAPER-MAKING; PRODUCTION OF CELLULOSE
    • D21CPRODUCTION OF CELLULOSE BY REMOVING NON-CELLULOSE SUBSTANCES FROM CELLULOSE-CONTAINING MATERIALS; REGENERATION OF PULPING LIQUORS; APPARATUS THEREFOR
    • D21C5/00Other processes for obtaining cellulose, e.g. cooking cotton linters ; Processes characterised by the choice of cellulose-containing starting materials
    • D21C5/02Working-up waste paper
    • YGENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02WCLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO WASTEWATER TREATMENT OR WASTE MANAGEMENT
    • Y02W30/00Technologies for solid waste management
    • Y02W30/50Reuse, recycling or recovery technologies
    • Y02W30/64Paper recycling

Definitions

  • This invention relates to the pulping of wet-strength pa'per broke. More particularly, the invention relates to. the pulping of broke carrying high molecular weight material or resin as agent imparting wet strength, so as to form a pulp which can be sheeted either alone or in admixture with fresh pulp to yieldlgood quality paper.
  • wet-strength broke is greatly facilitated by 'conta'cting the broke with a diluteaqueous solution of an oxidizing salt and maintaining the broke in contact therewith until the fiber-resin-fiber bonds therein have substantially loosened, that is, loosened to the point where the broke can be pulped in conventional pulping equipment such as a beater, hydropulper, refiner or dynapulper.
  • the process is useful in connectionwith .brokecon taining any adsorbed wet strength resin.
  • the invention does not depend upon any particular times, temperatures concentrations, or pHvalues. Good results have been obtained with oxidizing salt' concemv trations of A% to 5%, contact times of from a minute or less to an hour or two, and temperatures varying from room temperature to the boil.”
  • a substantial excess of oxidizing salt is present so' as to avoid undue prolongation of the treatment.
  • the pH of the oxidizing salt solution ordinarily need not be adjusted and satisfactory bond loosening takes place with minimal harm to the fibers With solution having pH values between-about 7 and 10.
  • a wetting agent may be added and is sometimes helpful particularly in connection with oily or waxy broke and a hot oxidizing salt solution is used. Temperatures .between F. and F. are suitable.v
  • the precise amount of oxidizing salt which should be added in each instance varies because of the difference in effectiveness of particular salts in loosening the fiber-resin-fiber bonds and the strength of the bonds resulting principally from the amount and kind of wet strength-resin present.
  • Termination of the treatment occurs when the fiberresin-fiber-bonds have loosened to such an extent that the broke can be disintegrated in ordinary papermaking equipment at hand.
  • the principal commercially available oxidizing agents have been tested, including sodium hypochloride (NaClO),- sodium chlorite (NaClO sodium chlorate (NaClO potassium chlorate (KClO), calcium hypochlorite [Ca(ClO) ammonium persulfate and hence the water-soluble metal hypochlorites are preferred.
  • Example 1 The effectiveness of a number of colorless oxidizing salts as pulping agents for several representative wetstrength papers is illustrated by the following. All tests were run :at room temperature without pH adjustment and the solutions were not agitated. In each instance 100 cc. of solution Was employed containing the percentage of oxidizing salt shown in the table and paper strips weighing about 0.5 gm. were employed as the test samples.
  • the strips were tested by cautiously pulling the sheets with the fingers in the same manner that cloth is tested for tendering, and the decrease in fiber-resin bonding was rated on a uniform scale according to which 0 designates practically no loss of strength (equivalent to no loss in bonding), 3 designates practically complete loss of wet strength, and l and 2 designate proportionate intermediate values.
  • Wet strength paper having a terminal bond strength rating between 2 and 3 can be pulped in a commercial beater .without need for steam-jet treatment, and a rating of 1-2 represents a very material loosening ofthe bonds.
  • the paper employed had been prepared in the labora tory in uniform manner by forming a beaten suspension of commercial unbleached northern kraft fibers at about 0.6% consistency, adding 3% of the wet strength resin shown in the table followed by 2% of alum (weights tory handsheet machine at a basis weight between 45,
  • the ethylenimine resin was prepared by homopolymerizing ethylenimine to the high viscosity necessary for wet strength purposes.
  • the resin was essentially a high molecular weight polyalkylenepolyamine.
  • the Hofmann resin was a linear carbon chain polymer every other chain carbon atom of which carried an amino group.
  • the resin was prepared in accordance with Example 4 of copending application Serial No. 363,394, filed June 22, 1953, by myself et al.
  • the Epi-TETA resin was prepared by the condensation of 0.6 mol of epichlorhydrin with 0.2 mol of triethylenetetramine, as shown in Example 1 of U. S. Patent No. 2,595,936.
  • the IBPA-DCE resin was made by refluxing 131.2 gm. of 3,3-iminobispropylamine, 87.5 gm. of 1,2-dichlorethane, and 50 cc. of water for two hours.
  • the resin was essentially a straight chain polyazoalkane probably containing a few six-membered rings resulting from condensation of dichlo-rethane with the polymeric NHCH CH -NH linkages formed by reaction of 3,3-iminobispropylamine with 1,2-dichlorethane.
  • Example 3 The efiect of heat is illustrated by the following.
  • Example 2 The procedure of Example 2 was repeated except that the concentration of the sodium hypochlorite was decreased to 0.25 and the temperature increased to 65 C. A pulping value of 1-2 was obtained in 10 minutes and a value between 2-3 and 3 in 30 minutes, showing that moderate temperature greatly accelerates the loosening of the bonds by the oxidizing salt.
  • Example 4 The procedure of Example 1 was repeated using paper prepared by addition of 3% (dry fiber basis) of the melamine-formaldehyde acid colloid of U. S. Patent No. 2,345,543 to slush stock followed by 1% alum. The paper was dried at 240 F. for 2 minutes and had wet. strength of 10 lb./ in.
  • the paper was soaked in 0.25% sodium hypochlorite solution at 65 C. for 30 minutes.
  • the paper had a NaClO Test Paper 5% NaClOz 5% Ca(ClO)2 5% (NH4)S2Q3 5% 211113802 Wet Strength pH WS Resin 1 1a Ethylen'unlne. 4. 5 5. 3 1b d0 9. 0 6. 9 4. 5' 5. 6
  • Example 2 The pulping of paper containing a phenol-resorcinolformaldehyde-bisulfite wet-strength resin is illustrated by the following. This resin was selected as it is generally considered to give outstandingly permanent wet strength at alkaline pH.
  • the resin corresponded to the resin of Example 3 of Canadian Patent No. 473,753 and was prepared by refluxing a reaction mixture comprising 131.6 parts of phenol, 9.5 parts of sodium metabisulfite, 66 parts of resorcinol and a total of 243.4 parts of 37% formaldehyde to a Gardner-Holdt viscosity of H under conditions set forth in the patent.
  • Wet strength paper containing the resin was made according to Example 1. The paper was heated for 2 minutes at 240 F. and had a wet strength of 7.5 lbs/in.
  • a process for the pulping of paper broke compose of cellulose fibers bonded together by an adsorbed content of at least one wet-strength resin which comprises: slurrying said broke with a dilute aqueous solution of an inorganic oxidizing salt thereby loosening the fiber-resinfiber bonds in said broke, and then subjecting the broke to mechanical pulping.

Description

U ited States harem All PULPING OF PAPER BROKE. CONTAINING. WET-STRENGTH RESINS Ronald R; House, Darien, and Yun Ju, Stamford,C'o'nn., assignors to American Cyanamid Company, New York, N. Y., a corporation of Maine No Drawing. Application September. 8, 1955 Serial No. 533,259.
3 Claims. (Cl. 921.4)
This invention relates to the pulping of wet-strength pa'per broke. More particularly, the invention relates to. the pulping of broke carrying high molecular weight material or resin as agent imparting wet strength, so as to form a pulp which can be sheeted either alone or in admixture with fresh pulp to yieldlgood quality paper.
In all paper mills a certain amount of the product is lost as trim or broke, andevery efiort is made to repulp this paper thereby eliminating waste. Paper carrying rosin size, Wax size, starch, clay,gums and similar additives can be charged directly intothe beater and reduced to a pulp without difiiculty by the normal actionthereof, although a short alkali soak is sometimes found helpful. Wet-strength webs (i. e.,- webs composed of cellulose fibers bonded together by an absorbed content of'wet strength resin) are not alfectedby this treatmerit to more than a negligibleextent,and up tothe'" present pulping of these webs has been deemed to require in combination an elevated temperature, an acid pH, and intensive mechanical disintegration assistedby steam jets. The method and apparatus therefor are respectively disclosed in U. S. Patents Nos. 2,394,273 to Thomas and 2,423,097 to Goehler et al.; see also the article by J. C. Barthel in the March- 21', 1955, issue of t the Paper Trade Journal and thevarticleby Trout'in.
TAPPI 34, 539 (1951).
The discovery has now been made that the pulping.
of wet-strength broke is greatly facilitated by 'conta'cting the broke with a diluteaqueous solution of an oxidizing salt and maintaining the broke in contact therewith until the fiber-resin-fiber bonds therein have substantially loosened, that is, loosened to the point where the broke can be pulped in conventional pulping equipment such as a beater, hydropulper, refiner or dynapulper. have found that in the great majority of instances soaking thebr-okefor less than anhour in a preferrednsalt solution loosens the fiber-resin-iiber bonds so extensively that the broke need not be subjected to the'steamejet disintegrationreferred to above andcan be added directly to the mechanical pulper, and that in :oth'erdnstances the bonds. are loosened to such anextent that much milder mechanical disintegration is 'sumcient as compared to the disintegration that would otherwise be necessary.
The process is useful in connectionwith .brokecon taining any adsorbed wet strength resin.
The invention does not depend upon any particular times, temperatures concentrations, or pHvalues. Good results have been obtained with oxidizing salt' concemv trations of A% to 5%, contact times of from a minute or less to an hour or two, and temperatures varying from room temperature to the boil."
According to one'method for employing the present invention broke, trim, or other scrap is charged directly,
to a dilute aqueous solution of an oxidizing salt in a tank and allowed to soak in the solution until the fiber resin-fiber bonds have substantially loosened. Stirring is helpfulbut not necessary, and no pH adjustment is generally required. When the desired loosening has occurred the solution is drained off, after which the paper is ready for pulping.
Preferably at the beginning of the soak a substantial excess of oxidizing salt is present so' as to avoid undue prolongation of the treatment. The pH of the oxidizing salt solution ordinarily need not be adjusted and satisfactory bond loosening takes place with minimal harm to the fibers With solution having pH values between-about 7 and 10. A wetting agent may be added and is sometimes helpful particularly in connection with oily or waxy broke and a hot oxidizing salt solution is used. Temperatures .between F. and F. are suitable.v The precise amount of oxidizing salt which should be added in each instance varies because of the difference in effectiveness of particular salts in loosening the fiber-resin-fiber bonds and the strength of the bonds resulting principally from the amount and kind of wet strength-resin present. Hence the optimum kind, amount and concentration of oxidizing agent in the solution are best predetermined by laboratory trial, using the procedures shown in the examples below as guides. Termination of the treatment occurs when the fiberresin-fiber-bonds have loosened to such an extent that the broke can be disintegrated in ordinary papermaking equipment at hand.
The principal commercially available oxidizing agents have been tested, including sodium hypochloride (NaClO),- sodium chlorite (NaClO sodium chlorate (NaClO potassium chlorate (KClO), calcium hypochlorite [Ca(ClO) ammonium persulfate and hence the water-soluble metal hypochlorites are preferred.
Example 1 The effectiveness of a number of colorless oxidizing salts as pulping agents for several representative wetstrength papers is illustrated by the following. All tests were run :at room temperature without pH adjustment and the solutions were not agitated. In each instance 100 cc. of solution Was employed containing the percentage of oxidizing salt shown in the table and paper strips weighing about 0.5 gm. were employed as the test samples.
The strips were tested by cautiously pulling the sheets with the fingers in the same manner that cloth is tested for tendering, and the decrease in fiber-resin bonding was rated on a uniform scale according to which 0 designates practically no loss of strength (equivalent to no loss in bonding), 3 designates practically complete loss of wet strength, and l and 2 designate proportionate intermediate values.
on this scale, Wet strength paper having a terminal bond strength rating between 2 and 3 can be pulped in a commercial beater .without need for steam-jet treatment, and a rating of 1-2 represents a very material loosening ofthe bonds.
The paper employed had been prepared in the labora tory in uniform manner by forming a beaten suspension of commercial unbleached northern kraft fibers at about 0.6% consistency, adding 3% of the wet strength resin shown in the table followed by 2% of alum (weights tory handsheet machine at a basis weight between 45,
and 50 lbs. per 25" x 40"/500 ream, pressing the sheets between blotters, and drying the sheets at a temperature between 240 and 260 F. for a time between 2 and minutes to give the initial wet strength shown in the table.
The ethylenimine resin was prepared by homopolymerizing ethylenimine to the high viscosity necessary for wet strength purposes. The resin was essentially a high molecular weight polyalkylenepolyamine.
The Hofmann resin was a linear carbon chain polymer every other chain carbon atom of which carried an amino group. The resin was prepared in accordance with Example 4 of copending application Serial No. 363,394, filed June 22, 1953, by myself et al.
The Epi-TETA resin was prepared by the condensation of 0.6 mol of epichlorhydrin with 0.2 mol of triethylenetetramine, as shown in Example 1 of U. S. Patent No. 2,595,936.
The IBPA-DCE resin was made by refluxing 131.2 gm. of 3,3-iminobispropylamine, 87.5 gm. of 1,2-dichlorethane, and 50 cc. of water for two hours. The resin was essentially a straight chain polyazoalkane probably containing a few six-membered rings resulting from condensation of dichlo-rethane with the polymeric NHCH CH -NH linkages formed by reaction of 3,3-iminobispropylamine with 1,2-dichlorethane.
.Results are as follows:
4 of Example 1 in dilute sodium hypochlorite solution at room temperature and pH 10 with following results:
Paper Strength After NaOlO Strength 1 2 10 15 30 Min Min. Min. Min. Min.
1 For explanation of ratings see Ex. 1.
These results show that a paper which is very resistant to alkali is quickly made ready for pulping when treated according to the present invention.
Example 3 The efiect of heat is illustrated by the following.
The procedure of Example 2 was repeated except that the concentration of the sodium hypochlorite was decreased to 0.25 and the temperature increased to 65 C. A pulping value of 1-2 was obtained in 10 minutes and a value between 2-3 and 3 in 30 minutes, showing that moderate temperature greatly accelerates the loosening of the bonds by the oxidizing salt.
Example 4 The procedure of Example 1 was repeated using paper prepared by addition of 3% (dry fiber basis) of the melamine-formaldehyde acid colloid of U. S. Patent No. 2,345,543 to slush stock followed by 1% alum. The paper was dried at 240 F. for 2 minutes and had wet. strength of 10 lb./ in.
The paper was soaked in 0.25% sodium hypochlorite solution at 65 C. for 30 minutes. The paper had a NaClO Test Paper 5% NaClOz 5% Ca(ClO)2 5% (NH4)S2Q3 5% 211113802 Wet Strength pH WS Resin 1 1a Ethylen'unlne. 4. 5 5. 3 1b d0 9. 0 6. 9 4. 5' 5. 6
Epi-TETRA 4. 5 4. 0 3b do 9.0 4.9 4a IBPA-DCE 4. 5 5.2 4b do 9. 0 6. 8
1 For description of resins see text above.
3 Wet strength, lb./in. (adjusted to lb. basis weight).
The results show that in every case rapid and extensive pulping rating of 1 at 30 minutes and a rating of 2-3 at loosening of its fiber-resin-fiber bonds was effected, the speed of loosening depending principally on the variables shown in the table.
Example 2 The pulping of paper containing a phenol-resorcinolformaldehyde-bisulfite wet-strength resin is illustrated by the following. This resin was selected as it is generally considered to give outstandingly permanent wet strength at alkaline pH.
The resin corresponded to the resin of Example 3 of Canadian Patent No. 473,753 and was prepared by refluxing a reaction mixture comprising 131.6 parts of phenol, 9.5 parts of sodium metabisulfite, 66 parts of resorcinol and a total of 243.4 parts of 37% formaldehyde to a Gardner-Holdt viscosity of H under conditions set forth in the patent.
Wet strength paper containing the resin was made according to Example 1. The paper was heated for 2 minutes at 240 F. and had a wet strength of 7.5 lbs/in.
60 minutes.
We claim: 1. A process for the pulping of paper broke compose of cellulose fibers bonded together by an adsorbed content of at least one wet-strength resin which comprises: slurrying said broke with a dilute aqueous solution of an inorganic oxidizing salt thereby loosening the fiber-resinfiber bonds in said broke, and then subjecting the broke to mechanical pulping.
2. A process according to claim 1 wherein the oxidizing salt is a water-soluble colorless metal hypochlorite.
3. A process according to claim 1 wherein the oxidizing salt solution is hot.
References Cited in the file of this patent UNITED STATES PATENTS 1,576,994 Plumstead Mar. 16, 1926 (Other references on following page) 5 6 UNITED STATES PATENTS 265,055 Great Britain Feb. 3, 1927 Wells Mar. 5, 1935 Fennel Oct. 10, 1950 OTHER REFERENCES Driessen Dec. 25, 1951 y: Pulp and Paper, vol. 1, page 602 (1952), Hill June 9, 1953 E cience Publishers, Inc., New York.
FOREIGN PATENTS Germany Nov. 10, 1915

Claims (1)

1. A PROCESS FOR THE PULPING OF PAPER BROKE COMPOSED OF CELLULOSE FIBRES BONDED TOGETHER BY AN ADSORBED CONTENT OF AT LEAST ONE WET-STRENGTH RESIN WHICH COMPRISES: SLURRING SAID BROKE WITH A DILUTE AQUEOUS SOLUTION OF AN INORGANIC OXIDIZING SALT THEREBY LOOSEING THE FIBER-RESINFIBER BONDS IN SAID BROKE, AND THEN SUBJECTING THE BROKE TO MECHANICAL PULPING.
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Cited By (25)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3051609A (en) * 1960-07-25 1962-08-28 Elihu D Grossmann Process of treating polyolefincoated paper
US3245868A (en) * 1963-09-06 1966-04-12 Black Clawson Co Continuous process for the recovery of paper broke containing a wet strength resin
US3407113A (en) * 1966-03-03 1968-10-22 American Cyanamid Co Pulping of wet strength paper with hypochlorous acid
US3427217A (en) * 1960-01-28 1969-02-11 Hercules Inc Repulping of wet-strength broke containing wet-strength resin
US3438851A (en) * 1965-03-02 1969-04-15 Euro Grondstof Nv Method for the regeneration of water-resistant paper as well as a method for the manufacture of paper from the material obtained and the sheets and webs of paper thus obtained
US3658640A (en) * 1970-04-29 1972-04-25 American Cyanamid Co Pulping of wet strength broke containing polyvinylamide-glyoxal resin
US3933577A (en) * 1971-01-08 1976-01-20 Penque Ronald A Process of sonically treating municipal waste to produce high quality paper pulp and fertilizer
US4416727A (en) * 1982-01-11 1983-11-22 Air Products And Chemicals, Inc. Process for recovering fiber from wet-strength resin coated paper
JPS5921790A (en) * 1982-07-23 1984-02-03 住友化学工業株式会社 Beating of wet strength paper
US4915783A (en) * 1988-12-27 1990-04-10 Monsanto Company Paper recycling aid
US5453159A (en) * 1993-11-04 1995-09-26 International Paper Company Deinking of recycled pulp
US5674358A (en) * 1992-09-03 1997-10-07 Hercules Incorporated Repulping wet strength paper and paperboard with persulfate and a carbonate buffer
AU685099B2 (en) * 1993-03-12 1998-01-15 Fmc Corporation Persulfate mixtures for repulping wet strength paper
US5830382A (en) * 1993-08-17 1998-11-03 Fmc Corporation Persulfate/metal mixtures for repulping and/or decolorizing paper
US5888350A (en) * 1993-08-17 1999-03-30 Fmc Corporation Method for repulping and/or decolorizing broke using persulfate/metal mixtures
US5994449A (en) * 1997-01-23 1999-11-30 Hercules Incorporated Resin compositions for making wet and dry strength paper and their use as creping adhesives
US6001218A (en) * 1994-06-29 1999-12-14 Kimberly-Clark Worldwide, Inc. Production of soft paper products from old newspaper
US6027610A (en) * 1994-06-29 2000-02-22 Kimberly-Clark Corporation Production of soft paper products from old newspaper
US6074527A (en) * 1994-06-29 2000-06-13 Kimberly-Clark Worldwide, Inc. Production of soft paper products from coarse cellulosic fibers
US6103861A (en) * 1997-12-19 2000-08-15 Hercules Incorporated Strength resins for paper and repulpable wet and dry strength paper made therewith
US6146497A (en) * 1998-01-16 2000-11-14 Hercules Incorporated Adhesives and resins, and processes for their production
US6296736B1 (en) 1997-10-30 2001-10-02 Kimberly-Clark Worldwide, Inc. Process for modifying pulp from recycled newspapers
US6355137B1 (en) 1997-12-31 2002-03-12 Hercules Incorporated Repulpable wet strength paper
US6387210B1 (en) 1998-09-30 2002-05-14 Kimberly-Clark Worldwide, Inc. Method of making sanitary paper product from coarse fibers
US20110030907A1 (en) * 2009-08-06 2011-02-10 Tech Corporation Co., Ltd. Method of producing recycled paper pulp from waste printed paper as raw material

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DE288640C (en) * 1900-01-01
GB265055A (en) * 1926-06-01 1927-02-03 Robinson Fiber Corp Improvements in or relating to the treatment of paper pulp stock
US1992977A (en) * 1933-01-26 1935-03-05 Lewis L Alsted Method of removing bleachable pigments from paper containing ligno-cellulosic constituents
US2525594A (en) * 1947-03-06 1950-10-10 Du Pont Deinking waste paper
US2580161A (en) * 1947-03-13 1951-12-25 Driessen Cornelius Clarence Process of deinking printed waste paper
US2641164A (en) * 1946-07-08 1953-06-09 Hill Harold Sanford Method for processing fibrous pulp

Patent Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE288640C (en) * 1900-01-01
GB265055A (en) * 1926-06-01 1927-02-03 Robinson Fiber Corp Improvements in or relating to the treatment of paper pulp stock
US1992977A (en) * 1933-01-26 1935-03-05 Lewis L Alsted Method of removing bleachable pigments from paper containing ligno-cellulosic constituents
US2641164A (en) * 1946-07-08 1953-06-09 Hill Harold Sanford Method for processing fibrous pulp
US2525594A (en) * 1947-03-06 1950-10-10 Du Pont Deinking waste paper
US2580161A (en) * 1947-03-13 1951-12-25 Driessen Cornelius Clarence Process of deinking printed waste paper

Cited By (30)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3427217A (en) * 1960-01-28 1969-02-11 Hercules Inc Repulping of wet-strength broke containing wet-strength resin
US3051609A (en) * 1960-07-25 1962-08-28 Elihu D Grossmann Process of treating polyolefincoated paper
US3245868A (en) * 1963-09-06 1966-04-12 Black Clawson Co Continuous process for the recovery of paper broke containing a wet strength resin
US3438851A (en) * 1965-03-02 1969-04-15 Euro Grondstof Nv Method for the regeneration of water-resistant paper as well as a method for the manufacture of paper from the material obtained and the sheets and webs of paper thus obtained
US3407113A (en) * 1966-03-03 1968-10-22 American Cyanamid Co Pulping of wet strength paper with hypochlorous acid
US3658640A (en) * 1970-04-29 1972-04-25 American Cyanamid Co Pulping of wet strength broke containing polyvinylamide-glyoxal resin
US3933577A (en) * 1971-01-08 1976-01-20 Penque Ronald A Process of sonically treating municipal waste to produce high quality paper pulp and fertilizer
US4416727A (en) * 1982-01-11 1983-11-22 Air Products And Chemicals, Inc. Process for recovering fiber from wet-strength resin coated paper
JPS5921790A (en) * 1982-07-23 1984-02-03 住友化学工業株式会社 Beating of wet strength paper
JPH0366434B2 (en) * 1982-07-23 1991-10-17 Sumitomo Chemical Co
US4915783A (en) * 1988-12-27 1990-04-10 Monsanto Company Paper recycling aid
US5674358A (en) * 1992-09-03 1997-10-07 Hercules Incorporated Repulping wet strength paper and paperboard with persulfate and a carbonate buffer
US5718837A (en) * 1993-03-12 1998-02-17 Fmc Corporation Persulfate mixtures for repulping wet strength paper
AU685099B2 (en) * 1993-03-12 1998-01-15 Fmc Corporation Persulfate mixtures for repulping wet strength paper
US5972164A (en) * 1993-03-12 1999-10-26 Fmc Corporation Persulfate mixtures for repulping wet strength paper
US5830382A (en) * 1993-08-17 1998-11-03 Fmc Corporation Persulfate/metal mixtures for repulping and/or decolorizing paper
US5888350A (en) * 1993-08-17 1999-03-30 Fmc Corporation Method for repulping and/or decolorizing broke using persulfate/metal mixtures
US5453159A (en) * 1993-11-04 1995-09-26 International Paper Company Deinking of recycled pulp
US6074527A (en) * 1994-06-29 2000-06-13 Kimberly-Clark Worldwide, Inc. Production of soft paper products from coarse cellulosic fibers
US6001218A (en) * 1994-06-29 1999-12-14 Kimberly-Clark Worldwide, Inc. Production of soft paper products from old newspaper
US6027610A (en) * 1994-06-29 2000-02-22 Kimberly-Clark Corporation Production of soft paper products from old newspaper
US5994449A (en) * 1997-01-23 1999-11-30 Hercules Incorporated Resin compositions for making wet and dry strength paper and their use as creping adhesives
US6296736B1 (en) 1997-10-30 2001-10-02 Kimberly-Clark Worldwide, Inc. Process for modifying pulp from recycled newspapers
US6103861A (en) * 1997-12-19 2000-08-15 Hercules Incorporated Strength resins for paper and repulpable wet and dry strength paper made therewith
US6245874B1 (en) 1997-12-19 2001-06-12 Hercules Incorporated Process for making repulpable wet and dry strength paper
US6355137B1 (en) 1997-12-31 2002-03-12 Hercules Incorporated Repulpable wet strength paper
US6146497A (en) * 1998-01-16 2000-11-14 Hercules Incorporated Adhesives and resins, and processes for their production
US6387210B1 (en) 1998-09-30 2002-05-14 Kimberly-Clark Worldwide, Inc. Method of making sanitary paper product from coarse fibers
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