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
  • 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
  • D01F9/20—Carbon filaments; Apparatus specially adapted for the manufacture thereof by decomposition of organic filaments from polyaddition, polycondensation or polymerisation products
  • D01F9/21—Carbon filaments; Apparatus specially adapted for the manufacture thereof by decomposition of organic filaments from polyaddition, polycondensation or polymerisation products from macromolecular compounds obtained by reactions only involving carbon-to-carbon unsaturated bonds
  • D01F9/22—Carbon filaments; Apparatus specially adapted for the manufacture thereof by decomposition of organic filaments from polyaddition, polycondensation or polymerisation products from macromolecular compounds obtained by reactions only involving carbon-to-carbon unsaturated bonds from polyacrylonitriles
  • D01F9/225—Carbon filaments; Apparatus specially adapted for the manufacture thereof by decomposition of organic filaments from polyaddition, polycondensation or polymerisation products from macromolecular compounds obtained by reactions only involving carbon-to-carbon unsaturated bonds from polyacrylonitriles from stabilised polyacrylonitriles
• • D—TEXTILES; PAPER
  • D01—NATURAL OR MAN-MADE THREADS OR FIBRES; SPINNING
  • D01D—MECHANICAL METHODS OR APPARATUS IN THE MANUFACTURE OF ARTIFICIAL FILAMENTS, THREADS, FIBRES, BRISTLES OR RIBBONS
  • D01D5/00—Formation of filaments, threads, or the like
  • D01D5/08—Melt spinning methods
• • 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
  • D01F6/00—Monocomponent artificial filaments or the like of synthetic polymers; Manufacture thereof
  • D01F6/28—Monocomponent artificial filaments or the like of synthetic polymers; Manufacture thereof from copolymers obtained by reactions only involving carbon-to-carbon unsaturated bonds
  • D01F6/38—Monocomponent artificial filaments or the like of synthetic polymers; Manufacture thereof from copolymers obtained by reactions only involving carbon-to-carbon unsaturated bonds comprising unsaturated nitriles as the major constituent
• • D—TEXTILES; PAPER
  • D02—YARNS; MECHANICAL FINISHING OF YARNS OR ROPES; WARPING OR BEAMING
  • D02J—FINISHING OR DRESSING OF FILAMENTS, YARNS, THREADS, CORDS, ROPES OR THE LIKE
  • D02J1/00—Modifying the structure or properties resulting from a particular structure; Modifying, retaining, or restoring the physical form or cross-sectional shape, e.g. by use of dies or squeeze rollers
  • D02J1/22—Stretching or tensioning, shrinking or relaxing, e.g. by use of overfeed and underfeed apparatus, or preventing stretch
• • D—TEXTILES; PAPER
  • D02—YARNS; MECHANICAL FINISHING OF YARNS OR ROPES; WARPING OR BEAMING
  • D02J—FINISHING OR DRESSING OF FILAMENTS, YARNS, THREADS, CORDS, ROPES OR THE LIKE
  • D02J1/00—Modifying the structure or properties resulting from a particular structure; Modifying, retaining, or restoring the physical form or cross-sectional shape, e.g. by use of dies or squeeze rollers
  • D02J1/22—Stretching or tensioning, shrinking or relaxing, e.g. by use of overfeed and underfeed apparatus, or preventing stretch
  • D02J1/228—Stretching in two or more steps, with or without intermediate steps
• • D—TEXTILES; PAPER
  • D02—YARNS; MECHANICAL FINISHING OF YARNS OR ROPES; WARPING OR BEAMING
  • D02J—FINISHING OR DRESSING OF FILAMENTS, YARNS, THREADS, CORDS, ROPES OR THE LIKE
  • D02J13/00—Heating or cooling the yarn, thread, cord, rope, or the like, not specific to any one of the processes provided for in this subclass
• • D—TEXTILES; PAPER
  • D06—TREATMENT OF TEXTILES OR THE LIKE; LAUNDERING; FLEXIBLE MATERIALS NOT OTHERWISE PROVIDED FOR
  • D06M—TREATMENT, NOT PROVIDED FOR ELSEWHERE IN CLASS D06, OF FIBRES, THREADS, YARNS, FABRICS, FEATHERS OR FIBROUS GOODS MADE FROM SUCH MATERIALS
  • D06M10/00—Physical treatment of fibres, threads, yarns, fabrics, or fibrous goods made from such materials, e.g. ultrasonic, corona discharge, irradiation, electric currents, or magnetic fields; Physical treatment combined with treatment with chemical compounds or elements
  • D06M10/008—Treatment with radioactive elements or with neutrons, alpha, beta or gamma rays

Definitions

• the present invention relates to a process for the thermal stabilization of melt-spun PAN precursors.
• the invention provides a continuous process for producing a thermally stabilized multifilament yarn from a fusible copolymer of polyacrylonitrile (PAN), in which a prestabilized IV multifilament yarn is thermally stabilized and in this case is at least temporarily stretched.
• PAN polyacrylonitrile
• the present invention also relates to a thermally stabilized IV multifilament yarn obtainable by a corresponding process and to a carbon fiber formed from the corresponding thermally stabilized IV multifilament yarn.
• polyacrylonitrile (PAN) or copolymers of polyacrylonitrile are the dominant polymers (> 95%) as the starting material for the production of precursor multifilament yarns and carbon fibers made therefrom.
• PAN polyacrylonitrile
• the wide range of Ex-PAN carbon fibers is provided by the completed with ultra-high-modulus pitch-based carbon fibers.
• PAN or PAN Copolymer Precursor fibers are commercially produced hitherto exclusively by wet or dry spinning processes.
• a solution of the polymers with concentrations ⁇ 20% is spun either in a coagulation bath or in a hot steam atmosphere, wherein the solvent diffuses out of the fiber.
• high quality precursors are produced.
• the solvents required on the one hand and their handling on the other hand, and the relatively low throughput of solution spinning processes result in the comparatively high production costs for PAN precursors, which account for about 50% of the costs of the final carbon fiber.
• one approach is to develop alternative less expensive precursor materials or precursor manufacturing processes and to tune the subsequent process steps of fiber spinning and stabilization / carbonization thereon.
• Promising is the approach to make PAN the processing by means of melt spinning accessible in order to significantly reduce the manufacturing cost of the PAN precursor.
• the object of internal plasticization is achieved by a copolymer composition which is disclosed in PCT / EP2015 / 070769 and which can be prepared by the process described in DE 10 2015 222 585.2.
• the resulting fusible and spinnable copolymer consists of acrylonitrile with at least one alkoxyalkyl acrylate and / or an alkyl acrylate and / or a vinyl ester, wherein the polymerization reaction is initiated free-radically and the heat flow released over the entire
• Period of addition of a radically polymerizable comonomer is at least temporarily steadily increasing, but never falling.
• the object of the invention is therefore to specify, starting from the prior art, a method with which a further stabilization of the PAN can be achieved.
• Precursor fiber is achieved, so that a safe further processing of Precursormaschinen is possible.
• Claim 20 specifies a multifilament yarn produced according to the method of the invention.
• Patent claim 21 relates to a fiber which has been formed by further heat treatment from the multifilament yarn according to the invention.
• the present invention thus relates to a continuous process for the preparation of a thermally stabilized multifilament yarn of a fusible copolymer of polyacrylonitrile (PAN), in which prestabilized
• Multifilament yarn or non-prestabilized multifilament yarn is fed continuously, wherein in the case of an unprestabilized multifilament yarn pre-stabilization and then neutralization is carried out and then the pre-stabilized multifilament yarn temperatures ⁇ ⁇ stabilized, wherein at least temporarily during, before and / or after the thermal stabilization Stretching the multifilament yarn is performed.
• pre-stabilized IV multifilament yarn is understood according to the invention to mean an ultrafilament yarn in which the originally meltable copolymers of polyacrylonitrile (PAN) were converted into an infusible state by a suitable process.
• the normalized to the filament diameter strength of the thermally stabilized multifilament yarn is at least 50 MPa, preferably at least preferably at least 75 MPa, more preferably at least 100 MPa, in particular at least 125 MPa.
• the multifilament yarn is stretched by 10 to 300%, particularly preferably by 20 and 200%, particularly preferably by 25 to 150%, in particular by 50 to 110%. Stretching around e.g. 10% means that the length of the multifilament yarn after stretching is 10% greater than before the stretching process, etc.
• the thermal stabilization can be carried out at least temporarily at temperatures of from 50 to 400.degree. C., preferably from 80 to 300.degree. C., more preferably from 90 to 270.degree. C., in particular from 180 to 260.degree.
• the thermal stabilization takes place by advancing the multifilament yarn through at least one oven or at least two furnaces connected in succession.
• the thermal stabilization is particularly preferably carried out in two stages, wherein the multifilament yarn is not stretched or is stretched to a lesser extent in the first stage than in the second stage and / or in the first stage at average lower temperatures than in the second stage. is siert.
• the two-stage thermal stabilization is particularly preferably carried out in at least two separate furnaces.
• the thermal stabilization can be carried out in such a way that rising or constant temperatures prevail in the advancing direction of the multifilament yarn.
• the thermal stabilization is carried out so that a degree of stabilization (DOS) of the copolymer of polyacrylonitrile from 20 to 75%, preferably from 25 to 60%, particularly preferably from 30 to 50%, in particular 30 to 47% results.
• DOS degree of stabilization
• the thermal stabilization can also be carried out in an oxidizing atmosphere, preferably an oxygen-containing atmosphere, in particular air.
• the thermal stabilization is performed by feeding the multifilament yarn through at least two sequentially connected ovens.
• the stabilization is preferably carried out so that after the exit of the thermally stabilized multifilament yarn from the last oven a degree of stabilization (DOS) of the copolymer of polyacrylonitrile of 25 to 60%, particularly preferably from 30 to 50%, in particular 30 to 47% results and / / or a strength of the thermally stabilized multifilament yarn is at least 50 MPa, preferably at least 75 MPa, more preferably at least 100 MPa, especially at least 125 MPa.
• DOS degree of stabilization
• the thermal stabilization is preferably carried out by applying tensile stress to the multifilament.
• the tensile stress serves to stretch the multifilament yarn.
• the tensile stress is preferably 0.1 to 10 cN / tex, more preferably from 0.5 to 5 cN / tex, particularly preferably from 1 to 3 cN / tex.
• the thermal stabilization is carried out over a period of 10 to 180 minutes, preferably 20 to 100 minutes, more preferably 30 to 60 minutes.
• the multifilament yarn is advantageously produced by melting and extruding the copolymer of polyacrylonitrile through at least one spinneret and spinning it into multifilaments.
• the pre-stabilization of the multifilament yarn can be carried out either in a separate, upstream of the process according to the invention stage. Likewise, the pre-stabilization can be carried out in situ during the process according to the invention, so that, for example, spinning a melt of the PAN copolymer to the multifilament yarn, a pre-stabilization and directly in the
• Connection can be made further stabilization by the method according to the invention.
• the pre-stabilization of the unprestabilized multifilament yarn is carried out as follows: i) by treatment with a mixture containing or consisting of at least one solvent for polyacrylonitrile and an aqueous alkaline solution, the mixture preferably being from 0.1 to 60% by volume of the mixture Solvent and from 40 to 99.9 vol .-% of the aqueous alkaline solution contains or consists thereof, wherein the solvent is in particular selected from the group consisting of dimethyl sulfoxide, dimethylformamide, dimethylacetamide, N-methylpyrrolidone, ethylene carbonate, propylene carbonate, aqueous Natriumrhodanid solutions and mixtures thereof, followed by neutralization of the multifilament yarn treated as described above and / or
• PAN Polyacrylonitrile
• the aforementioned first case of pre-stabilization advantageously takes place by performing the unprestabilized multifilament yarn by a modifying bath, containing the mixture at a temperature of 20 to 80 ° C, preferably from 40 to 65 ° C within a residence time of 5 s to 2 min, preferably from 10 s to 60 s or the unprestabilized multifilament yarn with the mixture is sprayed.
• the aqueous alkaline solution contains from 3 to 15 mol / l of at least one alkaline earth or alkali metal salt, preferably an alkali metal hydroxide, more preferably potassium hydroxide or sodium hydroxide.
• a neutralization is required, wherein preferably the previously pre-stabilized multifilament yarn passes through a neutralizing bath (wash bath) which contains an aqueous acidic solution having a pH of less than 3, preferably less than 2, more preferably less than 1, and temperatures of from 5 to 95 ° C and a residence time of 5 s to 2 min, preferably from 10 s to 60 s is realized.
• the alkali hydroxides taken up in the modifying bath from the pre-stabilized multifilament yarn are converted to monovalent water-soluble salts and washed out.
• the thermal stabilization from which the thermally stabilized multifilament yarn results a further temperature treatment under inert gas, in particular argon or nitrogen, at temperatures of 300 to 3000 ° C, preferably at temperatures of 300 to 1600 ° C for the production of carbon fibers connect.
• inert gas in particular argon or nitrogen
• the invention also relates to a multifilament yarn which has been produced by a method according to the invention as described above.
• the present invention relates to a carbon fiber, which was prepared by further thermal treatment, in particular on the previously described further temperature treatment of the multifilament yarn according to the invention.
• the starting material used is preferably a melt-spun continuous multifilament yarn of PAN copolymers (PCT / EP2015 / 070769) which has been converted into an infusible form by the process described in PCT / EP2015 / 070771.
• This fiber material is referred to below as "pre-stabilized PAN Precursor”.
• pre-stabilized PAN precursor is "thermally stabilized” by the method step according to the invention.
• the »prestabilized PAN precursor « is converted into a state which is preferably characterized by a
• the degree of stabilization is defined by the proportion of nitrile groups (C N) which have changed as a result of the heat treatment according to the process step according to the invention ("ex-nitrile groups"), based on the total number of nitrile groups in the starting material.
• the proportion of "ex-nitrile groups” is accessible via solid-state NMR measurements, whereby the proportion of unchanged nitrile groups (C N) is determined and subtracted from the total number of nitrile groups.
• the "pre-stabilized PAN precursor" is continuously transported preferably through a furnace which is opened at both ends and heated in a defined manner, which is rinsed with an air atmosphere.
• Stabilization degree increases, "pre-stabilized PAN precursor” acts.
• the mechanical fiber strengths drop considerably (FIG. 1), so that at temperatures of> 220 ° C. the "prestabilized PAN precursor” breaks and thus no continuous fiber transport is no longer possible after the method step according to the invention.
• Stretch stabilization allows strain rates from 0 to 200% to be achieved.
• Fig. 1 shows the mechanical strength of "thermally stabilized” fibers (according to the method of the invention) as a function of the applied temperature, each with an elongation of the "pre-stabilized PAN precursor" of 0%, 30% and 100% during this temperature application was applied. Fiber strengths of at least 50 MPa are necessary to be able to realize a continuous fiber transport and winding.
• the "thermally stabilized" fiber materials obtained by the process according to the invention can then be treated in a further thermal process step (Präcarbonmaschine) at temperatures between 300 and 1000 ° C and exposure times at appropriate temperatures of 10 to 100 min and in an "intermediate «Carbon fiber (C content> 80%) are transferred.
• the “intermediate” carbon fibers can then be subjected to a further thermal process step (carbonization), wherein the carbon content of the resulting fiber increases to> 90% by weight.
• carbonization a further thermal process step
• the “intermediate” carbon fibers are continuously transported through an oven and temperatures in the range of 1000 to 2000 ° C and exposure times at appropriate temperatures of 5 to 60 minutes applied.
• the carbon fiber thus obtained can still be graphitized at temperatures of 2000 to 3000 ° C.
• Both carbonized and graphitized fibers can be obtained by e.g. Heat treatment in an oxidizing atmosphere or plasma treatment or chemical treatment, are activated physically or chemically on the surface.
• Examples 1-9 The "pre-stabilized PAN precursor" is continuously transported through the inventive method step according to the test set out below by means of two tube furnaces (FIG. 2), which are rinsed with an air atmosphere.
• a degree of stabilization of> 15% is set in the fiber material by the application of temperatures (Ti - T 3 ) in the range from 100 to 200 ° C. and reaction times at corresponding temperatures of 20 to 80 min.
• the fiber material passes into the upper furnace (8) and also passes through it In this thermal process step (stretch stabilization), the fiber material at temperatures (T 4 -T 6 ) between 150 and 350 ° C and exposure times at appropriate temperatures of The speed ratio of the fiber transport devices (v 3 / v 2 ) stretched the fibers by 0%, 30% and 100%, respectively (Table 1)
• the result is a "thermally stabilized" fiber characterized by non-flammability, blackening, fiber strengths of> 50 MPa and fiber elongations of> 3% and a degree of stabilization (DOS) of at least 30%.
• a pre-stabilized ultrafilament yarn is unwound from a roll (1) and placed in a first oven (3) by means of a godet (2) running at a speed v x .
• the furnace is traversed by air and is divided into three temperature zones (Ti, T 2 , T 3 ).
• Ti for example, a temperature of about 100 ° C. can be set.
• Temperature in the temperature zone T 2 may for example be about 150 ° C, the temperature of the temperature zone T 3, for example, about 200 ° C.
• the separate temperature control in the individual zones of the furnace (3) can take place here by means of separate heating elements (4) provided in the respective zones.
• the unwound thread is transported continuously through the oven.
• the voltage applied to the multifilament yarn can be determined by means of a tension measuring sensor (5).
• the multifilament yarn emerging from the lower oven (3) is deflected by means of further godets (6) and (7) and fed to a second oven.
• the multifilament yarn in the upper furnace (8) is supplied, which is also traversed with air.
• This further furnace (8) is subdivided into three temperature zones T 4 , T 5 and T 6 , wherein the temperatures of the temperature zone T 4 are approximately 150 ° C., the temperature zone T 5 approximately 200 ° C. and in the temperature zone T 6 approx 250 ° C.
• separate heating elements (4) are available, which allow a separate temperature control of the zones.
• a further voltage measurement by means of the voltage sensor (9) can take place.
• the thermally stabilized multifilament yarn is drawn off by means of the godet (10), which runs at a speed v 3 .
• the speed v 3 is greater than the speed v 2 of the godet (7), so that at least in the upper furnace stretching of the multifilament yarn is made.
• the finally thermally stabilized multifilament yarn is finally wound up on a roll (11).
• Table 1 Characteristics of the "thermally stabilized” fibers according to the method of the invention. Fibers that were not stretched during the heat treatment (0%) can not be transported continuously. DOS: degree of stabilization

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• Engineering & Computer Science (AREA)
• Textile Engineering (AREA)
• Chemical & Material Sciences (AREA)
• Chemical Kinetics & Catalysis (AREA)
• General Chemical & Material Sciences (AREA)
• Mechanical Engineering (AREA)
• Artificial Filaments (AREA)
• Yarns And Mechanical Finishing Of Yarns Or Ropes (AREA)
• Inorganic Fibers (AREA)

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• 2017
  • 2017-01-10 US US16/476,739 patent/US11242623B2/en active Active
  • 2017-01-10 JP JP2019536989A patent/JP2020507016A/ja active Pending
  • 2017-01-10 EP EP17701277.0A patent/EP3568509A1/de active Pending
  • 2017-01-10 WO PCT/EP2017/050404 patent/WO2018130268A1/de unknown

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