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
  • D01F6/58—Monocomponent artificial filaments or the like of synthetic polymers; Manufacture thereof from homopolycondensation products
  • D01F6/74—Monocomponent artificial filaments or the like of synthetic polymers; Manufacture thereof from homopolycondensation products from polycondensates of cyclic compounds, e.g. polyimides, polybenzimidazoles
• • 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
  • D01F6/78—Monocomponent artificial filaments or the like of synthetic polymers; Manufacture thereof from copolycondensation products

Definitions

• the present invention relates to thermostable synthetic yarns based on polyamide-imide with improved properties.
• the strands according to the invention are also characterized by a polydispersity index I ⁇ 2.2 and tenacity> 45 cN / tex, a Young's modulus ⁇ 3.8 GPa, an elongation ⁇ 25% and a color defined by the luminance y > 25%, the degree of white DB ⁇ 30, the yellow index IJ> 170.
• the toughness is of the order of 50 to 55 cN / tex, the module ⁇ 4 GPa, the luminance y> 30%, of degree of white ⁇ 28, and the index of yellow> 190.
• the light stability of the PAIs according to the invention is also much improved compared to that of the PAI wires known hitherto. It is evaluated by the retention of mechanical properties: tenacity at break ⁇ 50%, working at break at 18%, elongation ⁇ 35%. The light stability is measured according to the method described below.
• the yarns according to the invention have a chemical structure as defined above in which R is a radical such that and preferably and R 1 preferably a radical R 2 preferably a radical and M is preferably Na or K.
• the PAI wires are also characterized by a value of the polydispersity index 1 ⁇ 2.2.
• This index corresponds to the ratio M w , the values of M not and M w being determined by gel exclusion chromatography (GPC) in the NMP Mn . at 80 ° C. and 0.1 mole / liter of lithium bromide, the masses being expressed relative to a polystyrene calibration.
• the polydipersity index of the PAI yarns according to the invention remains low: it corresponds to a narrowing of the distribution of the molecular masses. Surprisingly, it remains weak at the level of the finished threads despite the various treatments undergone by the filaments during their preparation.
• the threads according to the invention also have excellent mechanical and thermal characteristics, much superior to those of the polyamide-imide threads according to FR 2 079 785.
• the toughness is greater than or equal to 45 cN / tex, of preferably 50 or 55 cN / tex.
• the measurement is carried out on a manual or automatic dynamometer with constant gradient of elongation on a wire test piece subjected to longitudinal traction until it breaks.
• the elongation at break is measured as indicated above. It is less than or equal to 25%.
• the longitudinal Young E modulus of the PAI wires according to the invention is ⁇ 3.8 GPa, preferably ⁇ 4 GPa. This is the report obtained at the start of the force / elongation curve.
• the specific force (tenacity) corresponds to the ratio: ⁇ 1 being the increase in the length of the test piece at time t to which the actual titer corresponds and Io the initial length of the test piece.
• the degree of white defines a point of color in the chromaticity plane.
• the Yellow index is an expression of the color purity in the yellow.
• the light stability measurements are carried out in an enclosure which makes it possible to experimentally study the photoaging of polymers in a dry atmosphere.
• the samples to be tested are placed on a cylindrical turret driven by a circular rotational movement located in the center of a parallelepipedic enclosure, the four corners of which are occupied by a "medium pressure" mercury vapor lamp type MAZDA MA 400 Watts.
• the envelope allows only radiation above 300 nm (solar spectrum) to pass through.
• the temperature in the enclosure is 60 ° C.
• the 1.4 cm paper window on which the sample is fixed when determining the mechanical properties on INSTRON is itself placed on one of the 24 supports of the chamber turret. After the exposure, the paper window is recovered and the mechanical characteristics of the monofilament are determined according to the method of determining the mechanical properties indicated above.
• the yarns according to the invention have a clear superiority compared to known PAI yarns.
• the yarns according to the invention also have a much better thermal resistance than that of known PAI yarns: it is evaluated by the rate of degradation corresponding to a percentage of weight loss as a function of time at a temperature of 375 °, in air.
• the isothermal degradation of PAI yarns according to the invention is generally ⁇ 3% per hour, and preferably ⁇ 2% per hour.
• the filaments, threads, fibers according to the present invention can be used alone or mixed with natural or synthetic threads or fibers in order to modify or improve certain properties. They are particularly interesting for the production of work and protective clothing, thanks to their mechanical properties and their thermal and light resistance. In addition, the yarns obtained are easy to dye in all colors with basic dyes.
• the PAI yarns according to the present invention are obtained by wet spinning from solutions of polymer in a solvent or solvent mixture.
• concentration of the spinning solutions is between 4 and 35%, preferably between 5 and 35%.
• the polymers are dissolved in a solvent or solvent mixture containing from 5 to 100% by weight of dimethylethylene urea of pH ⁇ 7 and 0 to 55% of an anhydrous aprotic polar solvent such as N-methylpyrrolidone, dimethylacetamide, dimethylformamide, tetramethylurea or y butyrolactone.
• the solutions which can be used in the process according to the invention must have a viscosity of between 100 and 200 poises, preferably between 150 and 160 poises. They can also contain various adjuvants such as pigments, matifiers to improve certain properties.
• the PAI solutions are spun in a binary or ternary aqueous coagulating bath containing a solvent or solvent mixture in proportion of 30 to 80% of solvent and 20 to 70% of water, preferably 40 to 70% of solvent (s).
• the solvent used can be dimethylformamide, dimethylethylene urea or a mixture thereof.
• the spinning bath is maintained between 15 and 40 ° C, preferably 20 to 30 ° C.
• the length of the coagulating bath is adaptable generally depending on the solvent concentration and the temperature. Baths with a higher solvent content generally make it possible to obtain yarns with better stretchability, therefore better final properties. However, when the solvent concentration is higher, a longer bath length is necessary.
• the filaments leaving the coagulating bath in the gel state are then drawn, for example in air at a rate defined by the ratio x 100, V2 being the speed of the drawing rollers, V1 those of the delivery rollers.
• the rate of drawing of the strands in the gel state is at least 100%, preferably at least 110% or even more.
• the washed filaments are then dried by known means, for example in a dryer or on rollers.
• the temperature of this drying can vary within wide limits as well as the speed which is higher the higher the temperature. It is generally advantageous to carry out drying with a gradual rise in temperature, this temperature possibly reaching and even exceeding 200 ° C. for example.
• the filaments are then subjected to hot over-stretching to improve their mechanical qualities and in particular their toughness, which may be advantageous for certain jobs.
• This hot over-stretching can be carried out by any known means: oven, plate, roll, roll and plate, preferably in a closed enclosure. It must be carried out at a temperature of at least 150 ° C, which can reach and even exceed 200 to 300 ° C. Its rate is generally at least 150% but it can vary within wide limits depending on the qualities desired for the wire. finished.
• the total draw ratio is at least 250%, preferably at least 260%.
• the drawing and overdrawing assembly can be carried out in one or more stages, continuously or discontinuously with the preceding operations.
• secondary stretching can be combined with drying. For this, it is sufficient to provide, at the end of the drying, a higher temperature zone allowing overstretching.
• a PAI solution is prepared from: in dimethylethylene urea of pH ⁇ 7 so as to obtain a concentration of 21 0/0, the polydispersity index of the polymer is 1.78.
• the solution of viscosity 598 poises, is extruded in an aqueous coagulating bath containing dimethylethylene urea.
• the filaments leave the coagulating bath in the gel state and are drawn in air at ordinary temperature. They are washed with water in a bath to remove the solvent and dried on rollers.
• the solution of this polymer in the DMEU has a concentration of 21% and a viscosity of 781 poises. It is spun under the following conditions:
• the mechanical properties of the wires are as follows:
• a PAI solution of the same chemical structure as that described in Example 1 is prepared in a mixture of DMEU / DMF in proportion 72/28.

Landscapes

• Chemical Kinetics & Catalysis (AREA)
• General Chemical & Material Sciences (AREA)
• Engineering & Computer Science (AREA)
• Textile Engineering (AREA)
• Chemical & Material Sciences (AREA)
• Artificial Filaments (AREA)
• Polymers With Sulfur, Phosphorus Or Metals In The Main Chain (AREA)
• Macromolecular Compounds Obtained By Forming Nitrogen-Containing Linkages In General (AREA)
• Treatments For Attaching Organic Compounds To Fibrous Goods (AREA)
• Treatments Of Macromolecular Shaped Articles (AREA)
• Hydrogenated Pyridines (AREA)
• Compositions Of Macromolecular Compounds (AREA)
• Yarns And Mechanical Finishing Of Yarns Or Ropes (AREA)
• Materials For Medical Uses (AREA)
• Application Of Or Painting With Fluid Materials (AREA)
• Organic Insulating Materials (AREA)
• Chemical Or Physical Treatment Of Fibers (AREA)

Applications Claiming Priority (2)

Publications (2)

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Citations (4)

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• 1988
  • 1988-09-21 FR FR8812560A patent/FR2643089B1/fr not_active Expired - Fee Related
• 1989
  • 1989-08-14 NO NO893257A patent/NO893257D0/no unknown
  • 1989-08-31 NO NO89893499A patent/NO893499L/no unknown
  • 1989-09-14 EP EP89420348A patent/EP0360708B1/de not_active Expired - Lifetime
  • 1989-09-14 AT AT89420348T patent/ATE130879T1/de active
  • 1989-09-14 ES ES89420348T patent/ES2079384T3/es not_active Expired - Lifetime
  • 1989-09-14 DE DE68924946T patent/DE68924946T2/de not_active Expired - Lifetime
  • 1989-09-19 CA CA000611856A patent/CA1334612C/fr not_active Expired - Fee Related
  • 1989-09-19 RU SU894614932A patent/RU1838468C/ru active
  • 1989-09-20 IE IE301389A patent/IE69380B1/en not_active IP Right Cessation
  • 1989-09-20 CN CN89107401A patent/CN1031290C/zh not_active Expired - Fee Related
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• 1991
  • 1991-11-12 US US07/790,163 patent/US5159052A/en not_active Expired - Lifetime

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