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 cellulosic moldings, in which a suspension of cellulose in an aqueous solution of a tertiary amine oxide is converted into a moldable solution which is extruded through a shaping tool and passed into a precipitation bath.
• NMMO N-Methylmorpholine-N-oxide
• EP-A 0 553 070 Methods for producing cellulosic molded articles from a solution of cellulose in a mixture of NMMO and water are disclosed, for example, in US Pat. No. 4,246,221. Fibers produced in this way are characterized by a high fiber strength in the conditioned and in the wet state, a high wet modulus and a high loop strength.
• amine oxides, and especially NMMO have limited thermal stability, which varies depending on the structure.
• the monohydrate of the NMMO melts at temperatures of approx. 72 ⁇ C, the anhydrous compound melts at 172 ° C. If the monohydrate is heated, severe discolouration occurs at temperatures above 120/130 ° C. Such temperatures are quite common in processes for the production of cellulosic moldings. Above 175 “C there are strong exothermic reactions that can take an explosive course. In the course of these reactions, NMMO is thermally broken down primarily to N-methyl-morpholine, morpholine, formaldehyde and CO2.
• Temperatures are essentially gaseous, high pressures are created during the exothermic degradation of NMMO, which can damage equipment parts.
• EP-A 0 356 419 presented a process by means of which a moldable solution is obtained in one step from a suspension of cellulose in an aqueous tertiary amine oxide in a continuous manner. Since this process works very quickly, thermal degradation reactions during solution preparation can be minimized in this way.
• the malleable solution usually has to be transported through pipelines before spinning or e.g. are temporarily stored in buffer containers in order to be able to compensate for differences between the supply of new solutions and the demand from the spinning apparatus.
• PCT-WO 94/02408 and PCT-WO 94/08162 describe that stainless steel is used in the apparatuses published there without further specification.
• PCT-WO 94/28210 describes the use of stainless steel with AlSI code 430 for a perforated plate of a spinneret and stainless steel according to AlSI code 304 for the side walls of this spinneret.
• stainless steel or “stainless steel” refers to iron-based materials which are obtained by adding other metals, in particular chromium, but also e.g. Molybdenum or nickel have increased corrosion resistance. This is largely attributed to the formation of protective oxide layers of the added metals, which passivate the surface of the material. The presence of the alloy components thus leads to an additional passivation of the material surface and, at the same time, to a certain extent retains the corrosion of the base metal, which is usually present in excess.
• compositions of the common stainless steels are specified in various standards, e.g. in the AISI codes of the American Iron and Steel Institute, e.g. in KIRK-OTHMER, Encyclopedia of Chemical Technology, 2nd Edition (1969), Volume 18, pages 789 ff., or in the DIN standards listed in STAHLSCHLÜSSEL 1986 (Verlag StahlKey Wegst GmbH).
• the object of the present invention is to take measures in the process for producing cellulosic moldings from a solution of cellulose in a mixture of a tertiary amine oxide and water to minimize the above-mentioned degradation reactions and to avoid the catalytic effects mentioned.
• This object is achieved in that at least a portion of the material in contact with the moldable solution of apparatus and pipelines for transporting and processing the solution to a depth of at least 0.5 ⁇ m, preferably greater than 1 ⁇ m, calculated from the surface, at least 90% of at least one element from the group of titanium, zirconium, chromium and nickel in elemental form and / or in the form of compounds, with the proviso that the rest of the material none of the elements copper, molybdenum, tungsten or contains cobalt.
• the invention is based on the knowledge that decomposition reactions can occur on the surface of the materials in contact with the mouldable solution, which are catalyzed by the material itself, and that it is therefore possible to provide material surfaces that are in contact with the malleable solution do not have the catalytic effects listed above and therefore neither induce nor accelerate thermal degradation reactions.
• the use of elements or compounds in parts of the system in contact with the solution can minimize thermal degradation reactions of the solution in accordance with the composition according to the invention, i.e. that the degradation reactions in the formable solutions which wash around the surfaces composed according to the invention do not start much faster or more violently than in solutions which are not in contact with any technical material.
• the measures according to the invention show significantly better effects compared to materials known from the prior art, such as Stainless steel according to AISI codes 304 and 410.
• the elements or connections used according to the invention are therefore not only corrosion-resistant, so that essentially no entry of metal traces or traces of Metal ions occur in the moldable solution, but also do not have the catalytic effects observed with conventional stainless steel.
• the elements or compounds used in parts in contact with the solution according to the invention are therefore referred to below as essentially "non-catalytic" for the purpose of differentiating from other materials on which catalytic effects can be observed.
• Chromium in elemental form or in the form of compounds or as an essential component of a material as non-catalytic while the molybdenum which is in the same group of the periodic table and which increases corrosion resistance
• Alloy component is known, significantly accelerates the occurrence of exothermic reactions in contact with formable solutions.
• An essential component of the method according to the invention is that the elements or compounds used according to the invention form a layer of at least 0.5 ⁇ m, but preferably greater than 1 ⁇ m, on the surface of the materials in contact with the moldable solution.
• the top layer provided according to the invention contains a maximum of 10% other elements which may have catalytic effects. It is particularly advantageous if the layer is practical consists entirely of the non-catalytic elements and only traces of other elements are contained. However, material mixtures which, for example, consist only of 90% of the non-catalytic elements, also prove to be favorable in the process according to the invention. However, the elements copper, molybdenum, tungsten and cobalt must not be contained in such material mixtures.
• the layer provided according to the invention contains not only a non-catalytic element or a compound, but rather mixtures of a non-catalytic element and its compounds or also mixtures of a plurality of non-catalytic elements or their compounds.
• the process according to the invention is advantageously designed such that the oxides, carbides, nitrides, borides and / or silicides contained in the materials in contact with the moldable solution as compounds of the non-catalytic elements.
• Particularly preferred compounds are e.g. the oxides of chromium, zirconium, titanium and nickel as well as chromium boride, chromium nitride, chromium carbide, titanium carbide and titanium nitride.
• a further preferred embodiment of the invention is characterized in that the part of the materials in contact with the moldable solution is at least partially constructed in layers, the topmost layer in contact with the solution being at least 90% of at least one of the non-catalytic elements in elementary form Contains form and / or in the form of connections and this layer is applied to a material that may contain more than 10% other elements and / or connections.
• a further advantageous embodiment of the invention is characterized in that the materials in contact with the solution in those parts of apparatus and pipelines contain the at least one non-catalytic element in a depth of at least 0.5 ⁇ m in which the moldable solution stands or is stationary only moved at low speed.
• the object of the present invention is further achieved by using at least one element from the group of titanium, zirconium, chromium and nickel in elemental form and / or in the form of compounds in materials of apparatus and pipelines which are in contact with a moldable solution of cellulose in a mixture of a tertiary amine oxide and water in a proportion of at least 90% to a depth of at least 0.5 ⁇ m, preferably of larger than l ⁇ m solved.
• the respective powdered metals or metal compounds were homogeneously distributed into the ground cellulose solutions before the start of the test, a constant volume of metallic additives being used to standardize the surfaces (calculation of the mass via the density).
• Metal compounds were 0.035 cm 3 powder to 11.5 g cellulose solution in the tests in a SIKAREX oven and 7.5 * 10 ⁇ 4 cm 3 powder to 200 mg cellulose solution in the gas chromatographic tests.
• the tests were carried out in a Sikarex oven (TSC 512) from SYSTAG, the samples being heated in a sealed pressure vessel with a glass insert.
• NMM N-methyl-morpholine
• TM at ⁇ 10 .... is the jacket (furnace) temperature at which the temperature in the sample is 10 ° C higher than in the jacket due to an exothermic course
• Amine formation on the sample mixed with an additive means e.g. 2x amine formation compared to the blank value.
• the Sk2 (10) value provides clear information about the safety relevance of a material (or its catalytic activity) in the NMMO process, since it determines the temperature behavior (when does an exotherm occur?) And the tendency towards formation that is decisive for almost all metallically initiated degradation reactions key degradation product NMM.
• Titanium nitride ⁇ 10 ⁇ m 161.72
• Tungsten carbide ⁇ 10 ⁇ m 60.16
• Tables 1 and 2 clearly show that the elements used according to the invention, both in elemental form and in the form of compounds, have a significantly more favorable influence with regard to decomposition reactions than e.g. the elements iron, molybdenum, ruthenium and tungsten.
• the Sk2 (10) values for the elements used according to the invention are considerably above 100, and significantly less than 100 for catalytically active materials. Particularly when titanium or titanium compounds are used, exothermic reactions only set off just as late and with the same intensity as in a solution without any addition of materials.
• the following table shows the influence of the use of materials which have catalytic effects per se and which have been coated with non-catalytic substances.
• washers made of various basic materials were measured.
• the layer thickness was at least 2 ⁇ m in each case.
• This table also shows the favorable influence of the elements nickel, chromium and zirconium.

Landscapes

• Chemical & Material Sciences (AREA)
• Chemical Kinetics & Catalysis (AREA)
• General Chemical & Material Sciences (AREA)
• Engineering & Computer Science (AREA)
• Textile Engineering (AREA)
• Polysaccharides And Polysaccharide Derivatives (AREA)
• Catalysts (AREA)
• Organic Low-Molecular-Weight Compounds And Preparation Thereof (AREA)
• Extrusion Moulding Of Plastics Or The Like (AREA)
• Manufacture Of Macromolecular Shaped Articles (AREA)
• Rigid Pipes And Flexible Pipes (AREA)

Priority Applications (1)

Applications Claiming Priority (3)

Publications (2)

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• 1995
  • 1995-05-09 AT AT0078395A patent/AT403057B/de not_active IP Right Cessation
  • 1995-06-06 US US08/471,842 patent/US5766530A/en not_active Expired - Lifetime
  • 1995-06-26 BR BR9507476A patent/BR9507476A/pt not_active Application Discontinuation
  • 1995-06-26 CA CA002174094A patent/CA2174094A1/fr not_active Abandoned
  • 1995-06-26 DE DE59500054T patent/DE59500054D1/de not_active Expired - Fee Related
  • 1995-06-26 WO PCT/AT1995/000133 patent/WO1996027035A1/fr active Application Filing
  • 1995-06-26 CN CN95193917A patent/CN1151769A/zh active Pending
  • 1995-06-26 JP JP8513522A patent/JPH10502710A/ja active Pending
  • 1995-06-26 ES ES95922340T patent/ES2098168T3/es not_active Expired - Lifetime
  • 1995-06-26 EP EP95922340A patent/EP0743991B1/fr not_active Expired - Lifetime
  • 1995-06-26 AT AT95922340T patent/ATE145947T1/de not_active IP Right Cessation
  • 1995-06-26 DE DE19581451T patent/DE19581451D2/de not_active Expired - Fee Related
  • 1995-06-26 AU AU27066/95A patent/AU697159B2/en not_active Ceased
  • 1995-06-26 DK DK95922340.5T patent/DK0743991T3/da active
  • 1995-06-26 GB GB9607856A patent/GB2303576A/en not_active Withdrawn
• 1996
  • 1996-04-11 NO NO961424A patent/NO961424L/no unknown
  • 1996-04-11 FI FI961598A patent/FI961598A/fi unknown
  • 1996-12-05 GR GR960403141T patent/GR3021914T3/el unknown

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