Classifications

• • D—TEXTILES; PAPER
  • D01—NATURAL OR MAN-MADE THREADS OR FIBRES; SPINNING
  • D01F—CHEMICAL FEATURES IN THE MANUFACTURE OF ARTIFICIAL FILAMENTS, THREADS, FIBRES, BRISTLES OR RIBBONS; APPARATUS SPECIALLY ADAPTED FOR THE MANUFACTURE OF CARBON FILAMENTS
  • D01F2/00—Monocomponent artificial filaments or the like of cellulose or cellulose derivatives; Manufacture thereof

Definitions

• the invention relates to a process for the production of cellulose moldings, such as fibers, filaments or foils, from TCF or ECF bleached cellulose, in which the bleached cellulose is dissolved in an aqueous tertiary amine oxide to form a formable cellulose solution, the cellulose solution is deformed and by Coagulation of the deformed solution forms the shaped body.
• the invention further relates to the use of a TCF or ECF bleached cellulose for the production of cellulose moldings.
• the object of the present invention is to create a process for the production of cellulose moldings with reduced cellulose degradation starting from TCF or ECF bleached cellulose.
• the reduction in cellulose breakdown should be achieved essentially without special measures in the Lyocell process. Further advantages of the invention result from the following description.
• Pulp and fiber whiteness levels of different pulp provenances were determined, which were either ECF or TCF bleached.
• the whiteness of the pulp was determined in accordance with DIN 53145, part 2.
• the whiteness of the fiber was determined by the method described in WO 97/23666, page 6.
• the average degree of polymerization of the pulps by the Cuoxam method was about 550.
• the degrees of whiteness measured on the pulp and fiber are summarized in Table 1. Table 1
• the above-mentioned object is therefore achieved according to the invention in the method mentioned at the outset by reducing of cellulose degradation in the process, a TCF-bleached pulp with a carboxyl group content in the range of 1 to 35 ⁇ mol / g or an ECF-bleached pulp with a carboxyl group content in the range of 1 to 50 ⁇ mol / g is used. It has been shown that the lower the carboxyl group content of the pulp used, the more the cellulose degradation is kept behind in the course of the production and processing of the extrusion solution.
• TCF and ECF bleached pulps are used in the spinning solution production, the carboxyl group content of which lies in the ranges mentioned. Pulp with the carboxyl group contents mentioned can be produced by various pulp manufacturers.
• the reduced degradation of the spinning solution components also results in fewer coloring constituents, so that the whiteness of the shaped bodies formed is also improved secondarily.
• a TCF-bleached cellulose with a carboxyl group content in the range from 15 to 30 ⁇ mol / g or an ECF-bleached cellulose with an arboxyl group content in the range from 25 to 35 ⁇ mol / g is preferably used in the dissolving stage.
• the carboxyl group content of the cellulose to be used can be determined according to Döring, see K. Goetze, man-made fibers according to the viscose method, 2nd vol. 3rd edition, 1997, p. 1079.
• NMMO-MH N-methyl 'lmorpholin-N-oxide monohydrate
• a cellulose solution containing alkali or organic compounds can be formed, the latter containing at least four carbon atoms, at least two conjugated double bonds and at least two substituents -XH, where X is 0 or NR and R can be hydrogen or an alkyl group of 1 to 4 carbon atoms.
• the low degradation achieved according to the invention can be reduced even further by these solution additives.
• the amount of the organic compound may be in the range of 0.01 to 0.5% by mass based on the amount of the solvent. Suitable organic compounds are known from EP-A-0047 929. A commonly used compound is isopropyl gallate.
• the process according to the invention limits cellulose degradation to a proportion in the range from 3 to 20% by mass, based on the pulp used.
• the cellulose fraction degraded is preferably in the range from 8 to 15% by mass.
• the invention further relates to the use of a TCF-bleached cellulose or an ECF-bleached cellulose with a carboxyl group content in the range of 1 to 35 ⁇ mol / g or 1 to 50 ⁇ mol / g for the formation of a cellulose solution in a solvent containing tertiary amine oxide for the Production of moldings using the Lyocell process.
• the use of these pulps not only reduces the degradation in the course of the lyocell process, but also increases the whiteness of the shaped bodies formed.
• Long fiber sulfite pulp was bleached in a known manner by alkaline, peroxide-enhanced oxygen extraction, then with ozone and with peroxide.
• the bleaching methods are described, for example, in RP Singh, The Bleaching of Pulp, TAPPI Press, Atlanta, USA. Three different carboxyl group contents were set (Examples 1 to 3). Three more samples of the pulp were bleached with hypochlorite. The degree of polymerization and the initial degree of whiteness of the pulps were determined according to the above-mentioned methods, and the carboxyl and carbonyl group content of the pulp. Spinning solutions with 13% cellulose, 10.5% water and 76.5% NMMO were produced in a known manner from the bleached cellulose.
• the solutions were spun using the dry-wet process at 95 ° C. with a nozzle with a hole diameter of 65 ⁇ m.
• the degree of polymerization and the degree of whiteness were determined on the fibers obtained.
• the degree of polymerization was determined by the Cuoxam method, the degree of fiber whiteness by the method given above. The numerical values determined are given in Table 2.
• the degree of polymerization, the carboxal group content and the carbonyl group content and the starting whiteness were determined on four bleached dissolving pulps.
• Four spinning solutions with 13% cellulose, 10.5% water and 76.5% NMMO were produced from the cellulose.
• the zero shear viscosity was measured at 85 ° C on the spinning masses (Haake RS 75, year of construction 1998).
• the spinning solutions were spun at 95 ° C. with a nozzle with a hole diameter of 65 ⁇ m by the usual dry-wet method.
• the degree of polymerization of the cellulose was determined on the spinning solution and the degree of whiteness on the fibers. The results are summarized in Table 3.

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• Chemical & Material Sciences (AREA)
• Chemical Kinetics & Catalysis (AREA)
• General Chemical & Material Sciences (AREA)
• Engineering & Computer Science (AREA)
• Textile Engineering (AREA)
• Artificial Filaments (AREA)
• Polysaccharides And Polysaccharide Derivatives (AREA)
• Paper (AREA)

Applications Claiming Priority (3)

Publications (2)

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• 1999
  • 1999-10-07 DE DE19948401A patent/DE19948401C1/de not_active Revoked
• 2000
  • 2000-09-29 KR KR1020027004418A patent/KR100661454B1/ko not_active Expired - Fee Related
  • 2000-09-29 AT AT00978960T patent/ATE317027T1/de not_active IP Right Cessation
  • 2000-09-29 US US10/088,751 patent/US7175792B1/en not_active Expired - Lifetime
  • 2000-09-29 EP EP00978960A patent/EP1224343B1/fr not_active Expired - Lifetime
  • 2000-09-29 CA CA002385227A patent/CA2385227A1/fr not_active Abandoned
  • 2000-09-29 BR BRPI0014529-7A patent/BR0014529B1/pt not_active IP Right Cessation
  • 2000-09-29 EA EA200200382A patent/EA200200382A1/ru unknown
  • 2000-09-29 WO PCT/DE2000/003408 patent/WO2001025515A1/fr not_active Ceased
  • 2000-09-29 CN CNB008137498A patent/CN1180141C/zh not_active Expired - Lifetime
  • 2000-09-29 AU AU16456/01A patent/AU1645601A/en not_active Abandoned
  • 2000-09-29 DE DE50012169T patent/DE50012169D1/de not_active Expired - Fee Related
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  • 2000-12-28 TW TW089120885A patent/TW522178B/zh not_active IP Right Cessation
• 2002
  • 2002-04-04 NO NO20021588A patent/NO20021588D0/no not_active Application Discontinuation
  • 2002-05-06 ZA ZA200203556A patent/ZA200203556B/xx unknown

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