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
  • D01F6/00—Monocomponent artificial filaments or the like of synthetic polymers; Manufacture thereof
  • D01F6/02—Monocomponent artificial filaments or the like of synthetic polymers; Manufacture thereof from homopolymers obtained by reactions only involving carbon-to-carbon unsaturated bonds
  • D01F6/18—Monocomponent artificial filaments or the like of synthetic polymers; Manufacture thereof from homopolymers obtained by reactions only involving carbon-to-carbon unsaturated bonds from polymers of unsaturated nitriles, e.g. polyacrylonitrile, polyvinylidene cyanide
• • 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
  • D01D5/12—Stretch-spinning methods
  • D01D5/16—Stretch-spinning methods using rollers, or like mechanical devices, e.g. snubbing pins

Definitions

• the invention relates to threads and fibers made of polyacrylonitrile or polyacrylonitrile copolymers, which are predominantly composed of acrylonitrile building blocks and whose initial modulus - based on 100% elongation - is higher than 1300 cN / tex. Furthermore, a method for producing such threads and fibers is described.
• DE-A-2 851 273 describes a process in which the threads are drawn further directly after wet drawing in a "steam pressure drawing zone" at temperatures of 110 to 140 ° C. under the action of saturated steam under pressure.
• a steam pressure drawing zone Such a method is technically very complex in a continuous mode of operation, in particular because of the sealing problems of the hot pressure chamber.
• the threads according to the invention have an initial modulus of over 1300 cN / tex in the usual titer range (about 1.5 to about 15 dtex). Prefers these values are between 1400 and 2500 cN / tex.
• the threads and fibers with these high initial moduli are particularly well suited for technical applications such as B.
• the invention is also based on a method for producing these fibers and threads by a wet or dry spinning process, the wet stretching of the spun threads being carried out during the washing treatment, the threads then being dried and then subjected to hot stretching.
• the process according to the invention is characterized in that a polymer of the corresponding composition is dissolved in a solvent to form a spinning solution, from this spinning solution either by a dry spinning process or using a spinning bath from a mixture of solvent and water, threads which are spun by one of these spinning processes threads obtained after wet drawing, if appropriate in cable or strand form, are dried under tension on hot rollers and then subjected to contact drawing of at least 1: 1.5, the effective total drawing having to be at least 1: 9. Under a contact stretching, the stretching in the dry hot state, for. B. be understood by using panel radiators.
• the precipitation or solution polymers prepared by the customary processes can be used as polymer raw materials. Depending on the requirements for the areas of application, both homo- and copolymers of acrylonitrile can be used. The purity of the monomers used should be as high as possible.
• Suitable comonomers are all unsaturated compounds copolymerizable with acrylonitrile, of which the following should be mentioned here, for example: acrylamide, acrylic acid and its esters, vinyl esters and ethers such as vinyl acetate, vinyl stearate, vinyl butyl ether, haloacetic acid vinyl esters, such as bromoacetic acid vinyl ester, dichloroacetic acid vinyl styrene acid, trichloroacetic acid ester, trichloroacetate Maleimide, vinyl halides such as e.g. B. vinyl chloride, vinylidene chloride, vinyl bromide and sulfonate-bearing unsaturated compounds, etc.
• acrylamide acrylic acid and its esters
• vinyl esters and ethers such as vinyl acetate, vinyl stearate, vinyl butyl ether
• haloacetic acid vinyl esters such as bromoacetic acid vinyl ester, dichloroacetic acid vinyl sty
• Polymers can be used whose relative solution viscosities - measured in 0.5% dimethylformamide solutions - are in the range from 1.7 to 6.0. Good results under economical conditions are achieved with polymers which are in a viscosity range of approximately 1.85 to 3.5, particularly good results are provided by polymers in the viscosity range between 2.5 and 3.5.
• the polymers used should preferably have a content of at least 90% acrylonitrile units. Particularly good textile values are achieved with polymers that are made up of at least 99% acrylonitrile units.
• the dissolving conditions are to be selected so that the most homogeneous, gel particle-free spinning solutions are obtained.
• Scattered light measurements using a laser as the light source are particularly suitable for checking the quality of the spinning solution. Only flawless spinning solutions which show very low scattered light values enable the high draws required according to the invention.
• the spinning solutions can be prepared both continuously and discontinuously.
• inorganic or organic additives can be incorporated, such as. B. matting agents, stabilizers, flame retardants, etc.
• the spinning process according to the invention is characterized by a high effective total drawing of at least 1: 9.
• the effective total drawing should be at least 1: 9 by the method according to the invention. Effective total draw ratios of 1:10 to 1:25 are preferred, particularly preferred effective total draw ratios between about 1:12 and 1:22.
• the method according to the invention can be carried out on conventional thread or fiber spinning systems. New techniques that were not previously common are not required. In particular, it is not necessary to use a special stretching chamber in which the threads z. B. exposed in cable form to the action of steam under pressure. The process is characterized by high total stretch values of the freshly spun threads, one of which effective minimum draw of 900% is required. This effective total drawing takes place in several stages. First, the threads are wet-drawn in one or gradually in several hot baths before or after washing out the residual solvent content. The temperature of the stretching bath media, which usually consist of mixtures of water and the solvent, should be kept as high as possible. Temperatures a little below the boiling point of the bath liquid are preferred.
• baths which contain other stretching bath media are also possible, e.g. B. glycol or glycerol optionally in a mixture with the polymer solvent, at which stretching temperatures above 100 ° C can be selected.
• the threads are prepared in a preparation bath and then freed as much as possible of adhering water by the action of rotating pairs of press rollers.
• the preparation applied in the preparation bath can influence the stretching behavior of the threads. It should therefore be selected from known preparation mixtures that shows a low thread-thread friction.
• the threads are then dried under tension on hot rollers.
• a small amount of shrinkage which often proves to be advantageous for the subsequent stretching, can be permitted on drying;
• care must be taken that the cables always run under tension over the drying rollers.
• the temperatures of the rollers should be chosen so that the cable leaves the dryer with a very low residual moisture of less than 1%. Temperatures in the range from 140 to 220 ° C. have proven particularly favorable for these rolls, but this does not exclude the use of higher or lower temperatures. It is also possible to dry on the rollers at stepped temperatures.
• the spinning tow is stretched again using dry heat at least 1.5 times its length.
• This stretching can also take place in one or more stages.
• the heating of the cable can be done according to the usual methods in the art, e.g. B. by rotating hot rollers, by contact via hot plates, in a hot air duct or by radiation, in particular infrared radiation.
• Gradual stretching in which different heating methods are used, can also be used. Such combinations are always particularly advantageous when stretching from or between hot rolls in the first stretching stage and using one of the three other described methods in the second stage.
• the drawing temperatures are influenced by the type of polymer used and in part by the previous drawing and the drying conditions. A temperature range of approximately 120 to 250 ° C. is generally suitable, and the range of 140 to 200 ° C. is particularly favorable.
• the threads After stretching, the threads are cooled and, according to known methods, either wound up to form continuous material or cut into fibers with the desired cutting length. If required by the field of application, a special preparation can be applied to the threads or fibers before or after cutting.
• 1700 of a suspension precipitation polymer made from 99.5% acrylonitrile and 0.5% methyl acrylate with a relative viscosity of 2.85 are dispersed in 8300 g DMF at -30 ° C and for 90 minutes at 90 ° C with stirring to a homogeneous spinning solution solved. After filtering, the solution is pressed at a rate of 16.2 ml / min through a 100-hole nozzle, hole diameter 0.06 mm, into a precipitation bath consisting of 50% DMF and 50% water and a temperature of 50 ° C. The threads obtained are drawn off after an immersion length of 50 cm at a speed of 5.5 m / min.
• the thread is drawn off from the second duo at 33.3 m / min and over 4 heated plates, which alternately touch the thread from below and above, at temperatures of 145, 145, 165 and 168 ° C to 95 m / min with the help of a stretched unheated duos and then wound on spools.
• the effective total draw ratio is calculated to be 1: 17.3 in this case.
• the threads obtained in this way had the following properties:
• the individual capillaries of the thread produced in this way had the following properties:
• the thread obtained was drawn off after an immersion length of 50 cm at 5.0 m / min and in a drawing bath which contained 60% DMF and 40% water at 99 ° C., the thread was drawn to 33 m / min, then with water washed and dried after going through an aviva bath on 2 duos without approval of shrinkage.
• the surface temperatures of the duos were 120 and 140 ° C.
• the thread was then drawn to 68 m / min over 4 plates heated to 135 ° C., corresponding to an effective total drawing ratio of 1: 13.6.
• the individual capillaries of the thread showed the following properties:
• 1400 g of a precipitation polymer made of 100% acrylonitrile with a relative viscosity of 3.0 were dissolved in 8600 g of DMF to form a spinning solution, filtered and, at a delivery rate of 16 ml / min, through a 100-hole nozzle, hole diameter 0.06 mm, in one Precipitation bath consisting of 55% DMF and 45% water at 50 ° C.
• the thread obtained was drawn off from the precipitation bath at 5.5 m / min and drawn to 29.3 m / min in a drawing bath consisting of 60% DMF and 40% water at 99 ° C.
• the thread was then washed in water at 85 ° C., then passed through an Aviva bath and then dried to 2 duos, which had surface temperatures of 140 and 165 ° C. A shrinkage of 2.5 m / min was permitted on the duos, but the thread was withdrawn from the second duo at 30.3 m / min and over 4 hot plates with surface temperatures of 140, 140, 150 and 150 ° C to 72 m / min stretched.
• the individual filaments of the thread thus obtained showed the following properties:
• the thread was dried in the drum dryer in a first stage at 165 ° C. without the approval of shrinkage, in a second stage at 180 ° C., stretching to 63.9 m / min between the first and second stage.
• the thread then reached a third stage of the drum dryer, which was operated at 175 ° C. and the cable was stretched again to 69.2 m / min between the second and third stages.
• the cable passed through 8 hot plates, alternately arranged at the top and bottom, which had a surface temperature of 180 ° C, and between which the cable was stretched to 77.2 m / min, corresponding to an effective total stretching of 1: 11.9.
• Example 1 was repeated, but 5%, based on the polymer, of titanium dioxide was added to the spinning solution as a matting agent.
• the individual filaments of the thread had the following properties:
• the thread was drawn off at a speed of 5.0 m / min, in two drawing baths containing 60% DMF and 40% water at 99 ° C., drawn to 29.3 m / min in water washed at 85 ° C, finished, dried on 2 duos at 140 and 165 ° C with a shrinkage of 2.9 m / min, peeled off from the second duo at 30.3 m / min and on four hot plates at 140, 150.167 and 177 ° C stretched to 100 m / min.
• the effective total draw ratio here was therefore 1: 20.0.
• the thread thus spun showed the following properties:

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• Engineering & Computer Science (AREA)
• Textile Engineering (AREA)
• Chemical Kinetics & Catalysis (AREA)
• Health & Medical Sciences (AREA)
• Toxicology (AREA)
• Chemical & Material Sciences (AREA)
• Mechanical Engineering (AREA)
• General Chemical & Material Sciences (AREA)
• Artificial Filaments (AREA)
• Yarns And Mechanical Finishing Of Yarns Or Ropes (AREA)
• Materials For Medical Uses (AREA)
• Prostheses (AREA)
• Reinforced Plastic Materials (AREA)

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Publications (3)

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• 1980
  • 1980-07-23 DE DE19803027844 patent/DE3027844A1/de not_active Ceased
• 1981
  • 1981-07-16 DE DE8181105600T patent/DE3163294D1/de not_active Expired
  • 1981-07-16 EP EP81105600A patent/EP0044534B1/de not_active Expired
  • 1981-07-16 AT AT81105600T patent/ATE7236T1/de not_active IP Right Cessation
  • 1981-07-21 DD DD81231964A patent/DD201702A5/de unknown
  • 1981-07-21 IL IL63377A patent/IL63377A/xx unknown
  • 1981-07-22 NO NO812514A patent/NO152946C/no unknown
  • 1981-07-22 ZA ZA815005A patent/ZA815005B/xx unknown
  • 1981-07-22 JP JP56113779A patent/JPS5751810A/ja active Pending
  • 1981-07-22 DK DK326281A patent/DK326281A/da not_active Application Discontinuation
  • 1981-07-22 CA CA000382253A patent/CA1170011A/en not_active Expired
  • 1981-07-22 BR BR8104734A patent/BR8104734A/pt unknown

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