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
  • D01F9/145—Carbon filaments; Apparatus specially adapted for the manufacture thereof by decomposition of organic filaments from pitch or distillation residues

Definitions

• the present invention relates to a process for producing carbon fiber fabrics.
• Japanese Publication No.20281/1987 there is disclosed a process for producing a carbon fiber product in which as-spun pitch fibers are subjected to an initial carbonization treatment, then a bundle of the fibers is subjected to weaving and the resulting fabric is carbonized or graphitized.
• infusiblized fibers can be woven if they have a strength of about 40 kgf/mm2 and elongation to failure of 5%, and can be carbonized into a carbon fiber fabric.
• breaking of fibers of fuzzing occurs because the strength of the fibers in the weaving stage is not sufficiently high, and therefore even if the resulting fabric is carbonized or graphitized, it is impossible to obtain a high fiber volume fabric. Also a permanent strain may remain after carbonization, so the inherent strength cannot be developed when used as a composite material.
• the present invention is concerned with a process for producing a carbon fiber fabric, which process comprises making carbon fibers having a tensile strength exceeding 250 kgf/mm2 and an elongation to break of 0.4% to 10% into a two- or three-dimensional fabric, the said carbon fibers having been obtained by melt-spinning a carbonaceous pitch, making the resulting fibers infusible and then subjecting and thus-infusiblized fibers to a primary heat treatment at a tempera-ture exceeding 650°C and not higher than 2,500°C, and sub-jecting the two- or three-dimensional fabric to a secondary heat treatment at a temperature which is not lower than 700°C and is higher than the temperature in the primary heat treatment.
• the carbonaceous pitch there is used a coal or petroleum pitch having a softening point of 100°C to 400°C, preferably 150° to 350°C.
• Both optically isotropic and anisotropic pitches are employable examples of the carbona­ceous pitch, but particularly preferred is an optically anisotropic pitch having an optically anisotropic phase content of 60% to 100%.
• the melt spinning may be carried out by any suitable known method.
• the resulting pitch fibers are then rendered infusible.
• the infusiblization treatment may be performed at a temperature of 50°C to 400°C, preferably 100° to 350°C, in an oxidizing gas atmosphere.
• oxidizing gas there may be used air, oxygen, nitrogen oxide, sulfur oxide, halogen, and mixtures thereof.
• the primary heat treatment is conducted in an inert gas at a temperature exceeding 650°C and not higher than 2,500°C, preferably in the range of 1,000° to 2,000°C, more preferably 1,500° to 2,000°C.
• the treatment time is selectivelyed suitably so as to obtain primary heat-treated fibers having later-described tensile strength and elongation to failure, but usually it is in the range of 1 second to 10 hours.
• the primary heat-treated fibers obtained by going through the above primary heat treatment, have a tensile strength exceeding 250 kgf/mm2 and a breaking elongation of 0.4% to 10%.
• the tensile strength of the primary heat-treated fibers should be in excess of 250 kgf/mm2.
• the said tensible strength is not lower than 285 kgf/mm2, more preferably not lower than 300 kgf/mm2, and most preferably not lower than 330 kgf/mm2.
• the tensile strength in question is usually not higher than 1000 kgf/mm2. If the tensile strength is outside the range just specified, there will occur breakage of fibers and fuzz during weaving, with the result that a high fiber volume fabric cannot be obtained.
• the elongation to failure is in the range of 0.4% to 10%, preferably 0.6% to 10%, more preferably 0.6% to 5%. In the case of a three-dimensional fabric it is preferable that the elongation to failure be not lower than 0.6% because of a small radius of curvature of bundle in a fabric.
• the value of elastic modulus is determined optionally according to the combination of the above tensile strength and elongation to failure, but usually it is in the range of 5 to 100 x 103 kgf/mm2.
• the fiber diameter is in the range of 3 to 100 ⁇ m, preferably 5 to 30 ⁇ m.
• the foregoing primary heat-­treated fibers are made into a two- or three-dimensional fabric.
• fabrics as referred to herein are fabrics obtained using 100 to 25,000 continuous filaments. More concrete examples include two-dimensional fabrics such as plain weave, satin weave, twill weave, bias weave fabrics braid, and stitch knit, three-dimensional fabrics such as three-dimensional orthogonal fabric, leno, interlock and braid, as well as fabrics reinforced in three or more directions such as special shape fabrics, mat-like fabric and felt-like fabric.
• the fabric of the primary heat-treated fibers is subjected to a secondary heat treatment.
• the secondary heat treatment is performed at a temperature which is not lower than 700°C, for example in the range of 700°C to 3,300°C, preferably 1,000°C to 3,000°C, more preferably 1,500°C to 2,800°C, and which is higher than the temperature in the primary heat treatment.
• the secondary heat treat­ment temperature is higher by 50°C or more preferably by 100-­2,000°C, more preferably by 200-1,000°C, than the primary heat treatment temperature.
• the treatment time in the secondary heat treatment is selected optionally for obtain­ing the secondary heat-treated fabric falling under the scope of the present invention, but usually it is in the range of 1 second to 10 hours.
• a carbonaceous pitch was melt-spun and the resultant fibers were rendered infusible.
• the fibers thus infusibli­zed were subjected to a primary heat treatment at tempera­tures ranging from 1,700°C to 2,450°C.
• Using the fibers thus heat treated three-dimensional orthogonal fabrics were produced. Then, the fabrics were each subjected to a secondary heat treatment at 2,500°C.
• the three-dimensional fabrics thus heat treated were evaluated, the results of which are as shown in Table 1.
• Three-dimensional orthogonal fabrics were produced using the primary heat-treated fibers shown in Table 1, and then subjected to a secondary heat treatment at 2,500°C.
• the three-dimensional fabrics thus heat treated were evaluated, the results of which are as set forth in Table 1.
• Table 1 Primary Heat-Treated Fibers Evaluation of three-dimensional fabrics after sencondary heat treatment at 2,500°C

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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)
• Woven Fabrics (AREA)

Applications Claiming Priority (2)

Publications (3)

Family

ID=12430060

Family Applications (1)

Country Status (3)

Cited By (2)

Families Citing this family (1)

Family Cites Families (2)

• 1989
  • 1989-02-16 JP JP1035008A patent/JP2981667B2/ja not_active Expired - Fee Related
• 1990
  • 1990-02-16 DE DE1990626736 patent/DE69026736T2/de not_active Expired - Fee Related
  • 1990-02-16 EP EP19900301680 patent/EP0383614B1/fr not_active Expired - Lifetime

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