Using a dicarboxylic acid dialkyl ester brightening

• US 6,344,108 B1
• Filed: 08/30/1999
• Issued: 02/05/2002
• Est. Priority Date: 02/04/1997
• Status: Expired due to Fees

• Current Assignee: Stockhausen GmbH & Company Kg (Stockhausen Incorporated)
• Original Assignee: Stockhausen GmbH & Company Kg (Stockhausen Incorporated)
• Inventors: Hänssle, Peter, Von Medvey, Ingo, Werres, Joachim, Rajcsanyi, Thomas
• Primary Examiner(s): ALVO, MARC S
• Application Number:
  US09/355,333
• Time in Patent Office: 890 Days
• Field of Search: 162/72, 162/76, 162/164.3, 162/4, 162/5, 162/6, 162/8, 162/DIG.4, 162/25, 162/71, 162/91
• US Class Current: 162/25
• CPC Class Codes: B27N 3/00 Manufacture of substantially flat articles, e.g. boards, from particles or fibres
• CPC Class Codes: D21C 1/00 Pretreatment of the finely-divided materials before digesting of waste paper D21C5/02
• CPC Class Codes: D21C 3/003 with organic compounds D21C3/20 and D21C3/222 take precedence

Abstract

A process for producing fibrous materials for the manufacture of cellulose, paper or wood materials by using at least one dicarboxylic acid dialkyl ester and/or a copolymer of polyester-polyether and/or fatty acid polyol monopolyester, dipolyester, tripolyester and or higher polyester. Fibrous materials with an improved quality and higher yield are thus produced.

Claims

1. A process for producing wood pulp, comprising:

impregnating wood chips with a brightening agent comprising a dicarboxylic acid dialkyl ester, in an amount effective to increase brightness of said wood pulp;

followed by

mechanical defiberizing of the wood chips to produce a brightened wood pulp.

2. The process of claim 1, wherein the wood chips are impregnated with said brightening agents in a total amount of 0.005-5.0 wt %.

3. The process of claim 1, wherein the wood chips are impregnated with said brightening agents in a total amount of 0.01-2.0 wt %.

4. The process of claim 1, wherein the wood chips are impregnated with said brightening agents in a total amount of 0.01-1.0 wt %.

5. The process of claim 1, wherein the wood pulp is a mechanical, chemithermomechanical, or ground wood pulp.

6. The process of claim 1, wherein said wood chips comprise long-fibered raw material from C₄ plants.

7. The process of claim 6, wherein said C₄ plants are oil palms.

8. The process of claim 1, wherein said dicarboxylic acid dialkyl esters are n-alkyl or isoalkyl esters of adipic acid.

9. The process of claim 1, wherein said brightening agent further comprises esters of saturated and/or unsaturated C₈-C₁₈ fatty acids with multivalent alkanols having 2 to 6 carbon atoms selected from the group consisting of glycol, trimethylolpropane, glycerol, sorbitan, and sorbitol.

10. The process of claim 1, wherein the brightening agent further comprises polyethylene terephthalate-polyoxyethylene terephthalate- or polyoxyethylene terephtlalate-copolymers.

11. The process of claim 1, wherein the brightening agent is employed in the form of an aqueous emulsion.

12. The process of claim 1, wherein said brightening agent is used together with one or more compounds obtained from vegetable or animal oils in an amount of 0.001-5.0 wt. %, relative to the employed amount of wood chips.

13. The process of claim 1, wherein said brightening agent is used together with one or more compounds obtained from vegetable or animal oils, in an amount of 0.01-2.0 wt. %, relative to the employed amount of wood chips.

14. The process of claim 13, wherein said compound obtained from vegetable or animal oils is rape oil methyl ester, palm oil methyl ester, soybean oil methyl ester, colza oil methyl ester, tallow fatty acid methyl ester, and/or synthetic ester oils.

15. The process of claim 1, wherein said brightening agent is used together with one or more compounds obtained from vegetable or animal oils, in an amount of 0.01-1.0 wt. %, relative to the employed amount of wood chips.

16. The process of claim 1, wherein a bleaching operation is performed subsequent to the impregnating.