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
  • D21C9/001—Modification of pulp properties
  • D21C9/002—Modification of pulp properties by chemical means; preparation of dewatered pulp, e.g. in sheet or bulk form, containing special additives
  • D21C9/005—Modification of pulp properties by chemical means; preparation of dewatered pulp, e.g. in sheet or bulk form, containing special additives organic compounds

Definitions

• the present invention relates to a method for producing paper, in which an aqueous suspension of shredded cellulosic material is mechanically treated and subjected to a sheet formation process.
• pulp to be made into paper must be ground before sheet formation.
• grinding is to be understood as a mechanical treatment of the pulp in the suspended state, in which its physical properties are changed in such a way that it is suitable for the production of paper.
• the pulp consisting of cellulose fibers and water is ground, the fibers are cut, fibrillated and swollen. Fibrillation is the splitting of the fibers parallel to the fiber axis. A large part of the fibrils remain fringed on the fibers after grinding. Swelling and fibrillation are of great importance for the production of strong paper.
• the grinding process is an energy-intensive process. For products that require highly ground fiber, pulp grinding is even one of the most energy-intensive processes in paper production. Polymeric saccharides, monomeric and polymeric amines, amides and dyes are recommended as grinding aids (M. Milichovsky, Chemical aspects of pulp grinding, from: Zellstoff und Textil, 38, p. 17 (1989)). The degree of grinding is given in degrees Schopper-Riegler (SR). The strength of the paper obtained is generally higher, the higher the degree of grinding.
• SR Schopper-Riegler
• Machines such as Dutch, cone mills, refiner disc mills, pulper and pulper are used for grinding.
• the pulp is processed between a moving and a stationary machine part (manual of paper and Pappenfabrikation, (Papierlexikon), 2nd edition, Vol. II, LZ, 1971).
• the object of the invention is to further develop the conventional paper-making process in order to enable the production of high-strength papers without that conventional auxiliaries are used, the grinding time should be shortened as possible.
• the process according to the invention for the production of paper is based on a process in which an aqueous suspension of crushed cellulosic material, e.g. Pulp, mechanically treated and then subjected to a sheet formation process and is characterized in that the mechanical treatment is carried out in the presence of a tertiary amine oxide.
• the mechanical treatment is preferably carried out in a refiner.
• Tertiary amine oxides are known as alternative solvents for cellulose. From US Pat. No. 2,179,181 it is known, for example, that tertiary amine oxides can dissolve cellulose without derivatization and that cellulosic shaped bodies such as fibers can be obtained from these solutions by precipitation. US Pat. Nos. 3,447,939, 3,447,956 and 3,508,941 describe further processes for the preparation of cellulosic solutions, cyclic amine oxides preferably being used as solvents. In all of these processes, however, cellulose is physically dissolved at an elevated temperature.
• waste paper can also be added to the cellulosic material, for example cellulose, by the process according to the invention, and that even then the strength of the resulting paper is high. In this way, waste paper can thus be recycled using the method according to the invention. It is known that waste paper or repeatedly recycled cellulose fibers are not well suited for renewed sheet formation.
• the above-mentioned embodiment of the method according to the invention is based on the knowledge that shredded waste paper, which in the presence of a tertiary amine oxide is subjected to another grinding treatment together with other cellulosic material, can be used very well to produce a higher-quality paper.
• a preferred embodiment of the process according to the invention is that N-methylmorpholine-N- -oxide is used as the tertiary amine oxide.
• the aqueous phase of the suspension best contains the tertiary amine oxide between 55 and 72 mass%.
• the invention further relates to the use of a tertiary amine oxide as an auxiliary in the mechanical treatment of shredded cellulose-containing material for the production of paper.
• a tertiary amine oxide as an auxiliary in the mechanical treatment of shredded cellulose-containing material for the production of paper.
• the use of N-methylmorpholine-N-oxide has proven to be particularly advantageous.
• pulp from wood pulping using the sulphate and sulphite process was subjected to a standardized grinding treatment according to DIN 54 360 (November 1977) of the standards committee for paper and cardboard in the German Institute for Standardization e.V.) at room temperature.
• the purpose of such grinding treatment is to create conditions for assessing the strength properties of cellulose. This is only possible if test sheets are formed under specified, reproducible conditions and then tested for their strength properties.
• Sheet formation from the cellulose suspensions obtained in each case was carried out in accordance with DIN 54 358 Part (February 1981).
• the strength test (tear length) of the sheets obtained was carried out in accordance with the standardized method described in DIN 53 112 (October 1981). The results are shown in the tables below.
• Suspension medium water freeness ( * SR): 8 9 10 tearing length (m): 700 800 1000
• Suspension medium water Degree of grinding ( ⁇ SR): 32 42 47 Length of rip (m): 1800 2100 2500
• Suspension medium water freeness ('SR): 51 63 72 tearing length (m): 1100 1700 1600
• the method according to the invention is suitable for all types of pulp and is independent of the selected digestion.
• waste paper which consisted of fibers which had already been subjected to conventional grinding and sheet formation several times, together with cellulose to give paper of higher quality without the need for additional auxiliaries.

Landscapes

• Chemical & Material Sciences (AREA)
• Chemical Kinetics & Catalysis (AREA)
• General Chemical & Material Sciences (AREA)
• Life Sciences & Earth Sciences (AREA)
• Engineering & Computer Science (AREA)
• Wood Science & Technology (AREA)
• Paper (AREA)
• Making Paper Articles (AREA)
• Diaphragms For Electromechanical Transducers (AREA)
• Electronic Switches (AREA)
• Pharmaceuticals Containing Other Organic And Inorganic Compounds (AREA)

Priority Applications (11)

Applications Claiming Priority (2)

Publications (1)

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Country Status (14)

Cited By (3)

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Citations (1)

• 1993
  • 1993-09-06 AT AT0179193A patent/AT401072B/de not_active IP Right Cessation
• 1994
  • 1994-07-27 CA CA002147276A patent/CA2147276A1/en not_active Abandoned
  • 1994-07-27 ES ES94921526T patent/ES2087000T3/es not_active Expired - Lifetime
  • 1994-07-27 DK DK94921526.3T patent/DK0670926T3/da active
  • 1994-07-27 AU AU72220/94A patent/AU683074B2/en not_active Ceased
  • 1994-07-27 WO PCT/AT1994/000098 patent/WO1995007386A1/de active IP Right Grant
  • 1994-07-27 DE DE59400174T patent/DE59400174D1/de not_active Expired - Fee Related
  • 1994-07-27 AT AT94921526T patent/ATE136077T1/de not_active IP Right Cessation
  • 1994-07-27 SI SI9430003T patent/SI0670926T1/xx unknown
  • 1994-07-27 BR BR9405577-7A patent/BR9405577A/pt not_active Application Discontinuation
  • 1994-07-27 GB GB9508002A patent/GB2286606B/en not_active Expired - Fee Related
  • 1994-07-27 EP EP94921526A patent/EP0670926B1/de not_active Expired - Lifetime
  • 1994-07-27 DE DE4496602T patent/DE4496602D2/de not_active Expired - Fee Related
• 1995
  • 1995-05-03 NO NO951708A patent/NO951708D0/no unknown
  • 1995-05-05 FI FI952161A patent/FI952161A/fi unknown
• 1996
  • 1996-04-09 GR GR960401006T patent/GR3019611T3/el unknown

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Non-Patent Citations (2)

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