US3481828A - Bleaching of wood pulp with thiourea dioxide and zinc sulfate - Google Patents

Bleaching of wood pulp with thiourea dioxide and zinc sulfate Download PDF

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Publication number
US3481828A
US3481828A US531339A US3481828DA US3481828A US 3481828 A US3481828 A US 3481828A US 531339 A US531339 A US 531339A US 3481828D A US3481828D A US 3481828DA US 3481828 A US3481828 A US 3481828A
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US
United States
Prior art keywords
bleaching
thiourea dioxide
wood pulp
zinc sulfate
pulp
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Expired - Lifetime
Application number
US531339A
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English (en)
Inventor
John Harry Wallice Turner
Pavel Krug
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Borax Europe Ltd
Original Assignee
Hardman and Holden Ltd
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Hardman and Holden Ltd filed Critical Hardman and Holden Ltd
Application granted granted Critical
Publication of US3481828A publication Critical patent/US3481828A/en
Anticipated expiration legal-status Critical
Expired - Lifetime legal-status Critical Current

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Classifications

    • D—TEXTILES; PAPER
    • D21—PAPER-MAKING; PRODUCTION OF CELLULOSE
    • D21C—PRODUCTION OF CELLULOSE BY REMOVING NON-CELLULOSE SUBSTANCES FROM CELLULOSE-CONTAINING MATERIALS; REGENERATION OF PULPING LIQUORS; APPARATUS THEREFOR
    • D21C9/00—After-treatment of cellulose pulp, e.g. of wood pulp, or cotton linters ; Treatment of dilute or dewatered pulp or process improvement taking place after obtaining the raw cellulosic material and not provided for elsewhere
    • D21C9/10—Bleaching ; Apparatus therefor
    • D21C9/1084—Bleaching ; Apparatus therefor with reducing compounds

Definitions

  • the invention consists in a method of bleaching wood pulp, in which a bleaching composition is used containing 0.2% to 1.0% of thiourea dioxide and 1% to 5% of zinc sulphate, based on the weight of dry wood substance in the pulpto be bleached.
  • This invention relates to the bleaching of wood pulp. It is particularly concerned with the bleaching of mechanical wood pulp, in which the efiiciency of conventional bleaching agents, such as sodium'hydrosulphite and sulphoxylate is impaired due to the fact that such substances decompose at an early stage during the bleaching process.
  • conventional bleaching agents such as sodium'hydrosulphite and sulphoxylate
  • the invention is however also applicable of chemical wood pulp.
  • bleaching composition means of a bleaching composition. which contains thiourea dioxide as the active bleaching-agent.
  • the effectiveness of the bleaching composition containing thiourea dioxide can be further enhanced by an addition of zinc sulphate.
  • the invention may conveniently; be carried out by bleaching the wood pulp in a bath which contains 0.2%- 110% of thiourea dioxide and approximately five times this quantity of zinc sulphate, based on the weight of dry wood substance in the pulp to be bleached.
  • Optical bleaching agents may if desired be incorporated in the bleaching composition.
  • Sequestering agents such as poly'phosphates and ethylene diamine tetra-acetic acid may also be incorporated in the bleaching composition.
  • the process of bleaching wood ,,pulp or similar fibrous material with thiourea dioxide may be combined with other'treatments designed to impart specific properties to the finished product.
  • the reduction of flammability of ICC paper boards by treatment with solutions of borates or phosphates is well known; unfortunately, during the process the borate or phosphate solutions become coloured by organic materials in the wood pulp and the treated material becomes discoloured. Discolouration can be greatly reduced, if the fire retarding treatment is carried out simultaneously with a bleaching process with thiourea dioxide.
  • 'Qptimum bleaching efiects are obtained by using 0.05-3.00% weight/volume of thiourea dioxide in the flame retarding treatment solution.
  • EXAMPLE 1 Ground wood pulp containing 20 g. dry wood substance were treated in 100 cc. of a bleaching bath containing in solution 0.04 g. of thiourea dioxide and 0.2 g. of zinc sulphate. The initial temperature of the bath was 40 C., and the temperature was raised within 20 minutes to the boil, at which it was maintained for a further 20 minutes. After rinsing a bleached wood pulp with superior brightness was obtained.
  • EXAMPLE 3 was drawn. 0n drying the board showed considerable surface discolouration.
  • the second pad was treated with a 14% solution of sodium polyborate containing in addition 0.25% i(w./v.) thiourea dioxide. On drying considerably less discolouration occurred than was the case with no thiourea dioxide.
  • the third pad was treated with v a 14% polyborate solution containing 1% thiourea dioxide;
  • a process for bleaching wood pulp which comprises bleaching the wood pulp in a composition containing from 0.2% to 1.0% of thiourea dioxide and 1% to-5% of zinc sulphate based on the weight of dry wood subtance in the pulp to be bleached.
  • bleaching composition contains, in addition, a sequestering agent.

Landscapes

  • Life Sciences & Earth Sciences (AREA)
  • Engineering & Computer Science (AREA)
  • Wood Science & Technology (AREA)
  • Paper (AREA)
US531339A 1965-03-05 1966-03-03 Bleaching of wood pulp with thiourea dioxide and zinc sulfate Expired - Lifetime US3481828A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
GB9415/65A GB1079135A (en) 1965-03-05 1965-03-05 Improvements relating to bleaching of wood pulp

Publications (1)

Publication Number Publication Date
US3481828A true US3481828A (en) 1969-12-02

Family

ID=9871530

Family Applications (1)

Application Number Title Priority Date Filing Date
US531339A Expired - Lifetime US3481828A (en) 1965-03-05 1966-03-03 Bleaching of wood pulp with thiourea dioxide and zinc sulfate

Country Status (5)

Country Link
US (1) US3481828A (he)
FI (1) FI43527B (he)
GB (1) GB1079135A (he)
NO (1) NO118091B (he)
SE (1) SE306660B (he)

Cited By (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4244780A (en) * 1979-11-15 1981-01-13 Nalco Chemical Company Use of thiourea dioxide in pulp bleaching processes to preserve pulp strength and aid in brightness
US4675076A (en) * 1986-10-01 1987-06-23 Ppg Industries, Inc. Method for brightening pulp
DE19510278A1 (de) * 1994-03-22 1995-09-28 Brueggemann L Kg Bleichmittel zur Bleiche von Sekundärfaserstoffen für die Papierherstellung
US6428653B1 (en) 2000-12-04 2002-08-06 West Fraser Timber Co. Ltd. Method of bleaching with formamidine sulfinic acid using a reducing agent to eliminate residual peroxide
EP2062708A3 (de) * 2007-11-19 2009-11-25 Kronotec Ag Verfahren zur Verminderung der Emission von gesättigten und ungesättigten Aldehyden aus Holzwerkstoffen

Citations (9)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US354477A (en) * 1886-12-14 And frank a
US2259479A (en) * 1938-08-03 1941-10-21 Sales Affiliates Inc Process for the manufacture of the solid compound of hydrogen peroxide and urea
US2361639A (en) * 1940-07-15 1944-10-31 Henry A Wallace Process for defibering lignocellulosic materials
US2457856A (en) * 1939-03-22 1949-01-04 Zechuisen Jacob Johan Chemical retting process of producing bast fibers
US2838459A (en) * 1955-02-01 1958-06-10 Pennsalt Chemicals Corp Stabilization of solutions containing peroxygen compounds
US2859087A (en) * 1955-03-28 1958-11-04 Du Pont Process for bleaching webs of fibrous cellulose material with hydrogen peroxide vapor containing water vapor
US2872482A (en) * 1955-03-16 1959-02-03 Saint Gobain Process of making thiourea dioxide
US2956898A (en) * 1960-10-18 Certification of correction
US3384534A (en) * 1964-12-16 1968-05-21 Fmc Corp Bleaching of wood pulps with thiourea dioxide

Patent Citations (9)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US354477A (en) * 1886-12-14 And frank a
US2956898A (en) * 1960-10-18 Certification of correction
US2259479A (en) * 1938-08-03 1941-10-21 Sales Affiliates Inc Process for the manufacture of the solid compound of hydrogen peroxide and urea
US2457856A (en) * 1939-03-22 1949-01-04 Zechuisen Jacob Johan Chemical retting process of producing bast fibers
US2361639A (en) * 1940-07-15 1944-10-31 Henry A Wallace Process for defibering lignocellulosic materials
US2838459A (en) * 1955-02-01 1958-06-10 Pennsalt Chemicals Corp Stabilization of solutions containing peroxygen compounds
US2872482A (en) * 1955-03-16 1959-02-03 Saint Gobain Process of making thiourea dioxide
US2859087A (en) * 1955-03-28 1958-11-04 Du Pont Process for bleaching webs of fibrous cellulose material with hydrogen peroxide vapor containing water vapor
US3384534A (en) * 1964-12-16 1968-05-21 Fmc Corp Bleaching of wood pulps with thiourea dioxide

Cited By (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4244780A (en) * 1979-11-15 1981-01-13 Nalco Chemical Company Use of thiourea dioxide in pulp bleaching processes to preserve pulp strength and aid in brightness
US4675076A (en) * 1986-10-01 1987-06-23 Ppg Industries, Inc. Method for brightening pulp
DE19510278A1 (de) * 1994-03-22 1995-09-28 Brueggemann L Kg Bleichmittel zur Bleiche von Sekundärfaserstoffen für die Papierherstellung
US6428653B1 (en) 2000-12-04 2002-08-06 West Fraser Timber Co. Ltd. Method of bleaching with formamidine sulfinic acid using a reducing agent to eliminate residual peroxide
EP2062708A3 (de) * 2007-11-19 2009-11-25 Kronotec Ag Verfahren zur Verminderung der Emission von gesättigten und ungesättigten Aldehyden aus Holzwerkstoffen

Also Published As

Publication number Publication date
NO118091B (he) 1969-11-03
FI43527B (he) 1970-12-31
GB1079135A (en) 1967-08-16
SE306660B (he) 1968-12-02

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