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
  • D01F11/00—Chemical after-treatment of artificial filaments or the like during manufacture
  • D01F11/10—Chemical after-treatment of artificial filaments or the like during manufacture of carbon
  • D01F11/14—Chemical after-treatment of artificial filaments or the like during manufacture of carbon with organic compounds, e.g. macromolecular compounds
• • 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
  • D01F9/00—Artificial filaments or the like of other substances; Manufacture thereof; Apparatus specially adapted for the manufacture of carbon filaments
  • D01F9/08—Artificial filaments or the like of other substances; Manufacture thereof; Apparatus specially adapted for the manufacture of carbon filaments of inorganic material
  • D01F9/12—Carbon filaments; Apparatus specially adapted for the manufacture thereof
  • D01F9/14—Carbon filaments; Apparatus specially adapted for the manufacture thereof by decomposition of organic filaments
  • D01F9/16—Carbon filaments; Apparatus specially adapted for the manufacture thereof by decomposition of organic filaments from products of vegetable origin or derivatives thereof, e.g. from cellulose acetate

Definitions

• the present invention relates to a process for carbonizing cellulosic fibrous materials, in the presence of at least one organosilicon compound; this, to obtain fibrous carbon materials. Said carbonization can be carried out both continuously and discontinuously.
• the carbon fibrous materials obtained can in turn be heat treated (especially graphitized) to generate fibers having the desired properties.
• Carbon fibers with a cellulose precursor were the first carbon fibers manufactured in the world. From such cellulosic precursors, EDISON, at the end of the last century, obtained filaments for its incandescent lamps (US-A-223,898).
• Polyacrylonitrile has however proved for a long time a more suitable precursor for obtaining high-strength and high-modulus carbon fibers, more particularly intended for reinforcements of composite materials.
• ex-viscose carbon fibers have been used since 1955 in the manufacture of carbon / phenolic resin composites, used as thermal protection for propellants. These fibers, low modulus, have a limited thermal conductivity.
• the manufacture of these fibers requires a special rayon type precursor: a rayon with a disoriented crystalline texture (R. BACON, Carbon Fibers from Rayon Precursors, in Chemistry and Physics of Carbon, 1973, Vol. 2, Marcel Dekker, New-York and P. OLRY, 14 h Biennial Conference on Carbon, 1979).
• R. BACON Carbon Fibers from Rayon Precursors, in Chemistry and Physics of Carbon, 1973, Vol. 2, Marcel Dekker, New-York and P. OLRY, 14 h Biennial Conference on Carbon, 1979.
• the originality of the present invention lies in the selection of specific organosilicon compounds - additives for carbonization of cellulosic fibrous materials - which are particularly effective.
• Said compounds have been found to be very effective in improving the properties of the carbon fibers obtained after carbonization, this with any type of charred cellulosic materials (rayon, fibrans, in particular commercial); and, whether said carbonization is carried out continuously or discontinuously.
• the intervention of said compounds constitutes an undeniable advantage for the implementation of batch and continuous carbonizations, it proves to be essential for the continuous carbonization of certain substrates (it makes said continuous carbonization of said substrates possible. substrates).
• the present invention therefore relates to the use of a particular family of organosilicon compounds in said context.
• the present invention in fact relates to a process for obtaining fibrous carbon materials by carbonization implemented continuously or batchwise, in the presence of at least one organosilicon compound, of cellulosic fibrous materials.
• said organosilicon compound is chosen from the family of polyhydrosiloxanes, cyclic, linear or branched, substituted by methyl and / or phenyl groups, the number average molecular mass of which is between 250 and 10,000, advantageously between 2,500 and 5,000.
• oligomers in view of their number-average molecular mass, between 250 and 10,000, generally between 250 and 7,000, advantageously between 2,500 and 5,000 polyhydrosiloxanes.
• oligomers in view of their number-average molecular mass, between 250 and 10,000, generally between 250 and 7,000, advantageously between 2,500 and 5,000 polyhydrosiloxanes.
• Polyhydrosiloxanes of said family are currently available on the market. Some are notably marketed by Rhodia Silicones. These polyhydrosiloxanes are advantageously used prior to carbonization; the fibrous cellulosic materials being previously impregnated with these. For the implementation of such an impregnation, said polyhydrosiloxanes are generally used in solution in a solvent, such as perchlorethylene. Such a solvent can easily be removed before carbonization.
• said polyhydrosiloxanes, selected according to the invention intervene, of course, in an effective amount, generally at a rate of 1 to 10% by weight, relative to the weight of cellulosic materials. You should put enough to observe the expected effect but not too much because then you can observe an undesirable bonding effect. Those skilled in the art are able to optimize the amount of intervention of the organosilicon compounds, the use of which is recommended in the context of the process of the invention.
• organosilicon compounds could be further enhanced by the joint intervention of a mineral additive.
• the cellulosic fibrous materials are thus also impregnated, before their carbonization, with at least one mineral additive, acid or Lewis base.
• Said mineral additive can in particular be chosen from halides, sulphates and phosphates of ammonium, sodium, urea and their mixtures.
• ammonium chloride (NH 4 C1) or diammonium phosphate [(NH.), HPO 4 ].
• the additives of the invention are advantageously used, both in carbonization processes used batchwise and in carbonization processes used continuously. We have seen that they made possible the implementation of certain carbonizations continuously (carbonizations that it was only possible to implement, according to the prior art, discontinuously).
• the method of the invention is thus implemented continuously.
• the cellulosic fibrous material may in particular be in the form of threads or textile surfaces (fabrics, knits, felts, nonwovens, unidirectional sheets, unidirectional ribbons, etc.). Said cellulosic fibrous material may in particular consist of any type of rayon and fibranne.
• the process of the invention is, in this respect, particularly interesting: it leads, implemented with products available on the market, of wide distribution, to fibrous carbon materials, of high quality. According to the prior art, such high quality materials could only be obtained from cellulosic fibrous materials of very specific types.
• This pyrolysis carried out batchwise in the context of the example, may well be carried out continuously.
• the carbon filaments extracted from the carbonized wire have a breaking strength of 1,125 MPa and a module of 40 GPa, for a diameter of 5.8 ⁇ m.
• the carbonization shrinkage is 40% along the axis of the fibers.
• the carbonization yield is 15.6%.
• a cellulose yarn identical to that of Example 1 is desensed with perchlorethylene, then impregnated with 2.5% by weight of a polyhydromethylsiloxane resin sold by the company Rhodia Silicones (under the reference: RHODORSIL RTV 141 B) by soaking in a solution at 3% by weight of the product in perchlorethylene.
• RHODORSIL RTV 141 B a polyhydromethylsiloxane resin sold by the company Rhodia Silicones
• the carbon filaments extracted from the wire have a breaking strength of 1100 MPa, a module of 40 GPa, a diameter of 5.7 ⁇ m.
• the carbonization shrinkage is 40% along the axis of the fibers.
• the carbonization yield is 15.2%.
• a cellulose yarn identical to that of Example 1 is desensed and then impregnated with the organosilicon additive as in Example 1. It is then also impregnated with 8% by weight of NH 4 Cl by passage through an aqueous solution with 13% by weight of said NH C1. The wire is dried at 100 ° C for 30 min and the excess NH Cl is removed by rinsing for a few seconds with distilled water.
• Said wire is dried at 100 ° C for 1 hour then undergoes pyrolysis up to 1200 ° C as in Example 1.
• the tensile strength of the carbon filaments extracted from said carbonized wire is 1,200 MPa and their modulus of 45 GPa, for a diameter of 8.3 ⁇ m.
• the shrinkage during carbonization is 32.3.
• a cellulose yarn identical to that of Example 1 is desensimed with perchlorethylene and then, without impregnation with the polyhydrosiloxane additive, it is pyrolysed according to the thermal profile indicated in said Example 1.
• the breaking strength of the carbon filaments extracted from the wires obtained is only 660 MPa, their modulus is 38 GPa.
• the diameter of said filaments is 5.8 ⁇ m.

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• Chemical & Material Sciences (AREA)
• Chemical Kinetics & Catalysis (AREA)
• General Chemical & Material Sciences (AREA)
• Engineering & Computer Science (AREA)
• Textile Engineering (AREA)
• Inorganic Fibers (AREA)
• Treatments For Attaching Organic Compounds To Fibrous Goods (AREA)
• Polysaccharides And Polysaccharide Derivatives (AREA)
• Silicon Polymers (AREA)

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• 1999
  • 1999-12-06 FR FR9915327A patent/FR2801906B1/fr not_active Expired - Fee Related
• 2000
  • 2000-05-12 UA UA2002064661A patent/UA72289C2/uk unknown
  • 2000-12-05 EP EP00985406A patent/EP1268895B1/de not_active Expired - Lifetime
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  • 2000-12-05 RU RU2002115275/04A patent/RU2258773C2/ru not_active IP Right Cessation
  • 2000-12-05 WO PCT/FR2000/003388 patent/WO2001042541A2/fr active Search and Examination
  • 2000-12-05 US US10/148,777 patent/US7175879B2/en not_active Expired - Lifetime
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