JPH02216219A - Production of woven fabric of carbon fiber - Google Patents

Abstract

PURPOSE:To obtain the subject woven fabric having little fluffs by melt-spinning a carbonaceous pitch, infusibilizing the fiber, subjecting to the primary heat- treatment at a specific temperature, forming a woven fabric with the obtained fiber and subjecting the fabric to the secondary heat-treatment at a specific temperature. CONSTITUTION:A carbonaceous pitch having a softening point of 100-400 deg.C (e.g. coal or petroleum pitch) is spun in molten state and infusibilized in an oxidizing gas atmosphere at 50-400 deg.C. The infusibilized fiber is subjected to the primary heat treatment in an inert gas at 650-2500 deg.C to obtain a primary heat-treated fiber having a tensile strength of >=250kgf/mm<2> and an elongation at break of 0.4-10%. A two-dimensional or three-dimensional woven fabric is produced by using the primary heat-treated fiber and the fabric is subjected to the secondary heat-treatment at a temperature not lower than 700 deg.C and higher than the primary heat treatment temperature to obtain the objective fabric free from baking warpage.

Description

[Detailed description of the invention] 0 usage limit The present invention relates to a method for manufacturing carbon m-fiber fabric.

Jubei Rikigen” Carbon! In addition to weaving carbon fiber as a finished product, there are methods for producing fiber fabrics, as well as a method of weaving an intermediate product and then carbonizing or graphitizing it. No. 63-120136 states that the strength of carbon T fiber is 15 to 250 kg f / m + a 1 (medium is 05
~80%, elasticity Σ plan is 400~40,000kg E/
nym2, and when the carbon m fibers are heat treated in a relaxed state, both strength and elastic modulus increase to 11 times or more than before heat treatment, and the strength is 150 kgf/wa2 or more and the elastic modulus is 40.000 kgf/rrm2 or more. A three-dimensional fabric is disclosed that includes at least one component of pitch-based carbon fibers that have the ability to

Ma; l' = M public 1 [No. 62-20281 Niit, pitch tao is subjected to initial carbonization treatment in the range of 400 to 650°C, and then carbonized and graphitized carbon by knitting and weaving a bundle! A method for producing a male product is disclosed.

On the other hand, Carbon-Fiber-Reinforce
d Plastics, Bamberg, WestG.
Germany, May 11-12, 1977 states that it is possible to weave invulnerable fibers with a strength of about 40 kgf/2 and a breaking elongation of 5%, and if this is carbonized, #, taa
v! There is a description that it is an i product.

Problems to be Solved by the Invention However, when manufacturing m-products using the above-mentioned conventional technology, the strength is not sufficient during the weaving stage, and thread breakage and fluff occur, so it is necessary to carbonize or graphitize the material after weaving. However, it is not possible to produce high-density objects. Or 1, burnt marks remain after carbonization, making it impossible to develop the original strength when used as a composite material.

The present inventors have completed the present invention as a result of research on a method for solving the nE gap point and efficiently producing a carbon fiber fabric with less fluff and no burning curls.

The present invention is obtained by melt-spinning carbonaceous pitch and subjecting it to a primary heat treatment at a temperature of more than 650°C and less than 2500°C, and has a tensile strength of 250k.
gf/m2 and having a breaking elongation of 04 to 10% is made into a two-dimensional or three-dimensional woven fabric, and this woven fabric is heated at a temperature of 700° C. or higher and at the primary heat treatment temperature. This invention relates to a method for producing a carbon fiber fabric, which is characterized by performing a secondary heat treatment at a temperature higher than that of the present invention.

Hereinafter, the method for manufacturing carbon fiber fabric according to the present invention will be described in detail.

As the carbonaceous pitch, coal-based or petroleum-based pitch having a softening point of 100 to 400°C, preferably 150 to 350°C is used. As the carbonaceous pitch, either optically isotropic pitch or anisotropic pitch can be used, but optically anisotropic pitch with an optically anisotropic phase content of 6O-100% is particularly preferably used. Let it go.

Melt spinning is performed by a known method. The collected pitch fibers are then subjected to an infusible treatment.

The infusibility treatment can be carried out at 50 to 400°C, preferably 100 to 350°C, in an oxidizing gas atmosphere. Oxidizing gases include air, oxygen, nitrogen oxides, sulfur oxides,
Halogens or mixtures thereof can be used.

The primary heat treatment was performed at a temperature exceeding 650°C and 2500°C in an inert gas.
The reaction is carried out at a temperature of 1000 to 2000°C, preferably 1500 to 2000°C. The treatment time is selected as appropriate to produce the primary heat-treated fibers having the tensile strength and elongation at break described below, but is usually 1 second to 10 hours. In the method of weaving fibers treated at a temperature lower than the above range and then heat-treating them at a higher temperature, the carbonization state is low, so the so-called burning curls or weaving curls remain on the m male, and the fibers are molded in a bent state. If you pull this, it will break at the inflection point.

1 fire heat treatment! An is a fiber obtained by the above-mentioned primary heat treatment, and has a tensile strength of more than 250 kgf/m2 and a breaking elongation of 04 to 10%.

Primary heat treatment I! It is an essential requirement that the tensile strength of 1m or so exceeds 250kgf/m", preferably 285kgf/m".
kgf/llll12 or more, more preferably 300k
g f/R” or more, most preferably 330 kgf/
It's more than just a vote. There is no upper limit, but it is usually 50
0 kgf/m+m' under breath. Is the tensile strength within the above range? If not, thread breakage and fuzz will occur during weaving.
Also, it is not possible to produce high-density fabrics.

The elongation at break is 0.4-10%, preferably (0.6-10%)
%, more preferably 0.6 to 5%. Note that since the three-dimensional fabric has a small radius of curvature, it is preferable that the elongation at break is 06% or more.

The elastic modulus is arbitrarily determined by the combination of the tensile strength and elongation at break, but is usually 5 to 100100 x 103/m.
It is 2.

The diameter of the fibers is 3 to 100 μm, preferably 5 to 30 μm.
It is.

In the present invention, the above-mentioned primary heat-treated fibers are formed into a two-dimensional or three-dimensional woven fabric. The woven fabric mentioned here refers to 2-dimensional fabrics such as satin weave, twill weave, bias weave, or 3-dimensional fabrics such as orthogonal, intertwined, plaid, etc. These include deformed fabrics, mat-like molded products, felt-like molded products, etc. that are reinforced in three or more directions.

The woven fabric formed from this primary heat-treated fiber is subjected to a secondary heat treatment. 2
The next heat treatment is 700°C or higher, for example 700-3300°C,
Preferably 1000-3000°C, more preferably 15
The temperature is 00 to 2800°C and higher than the primary heat treatment temperature. Usually, it is carried out at a temperature higher than the primary heat treatment temperature by 5θ°C or more. gf good: good 100~2000℃,
More preferably, it is carried out at a temperature higher than 200-1000°C. The processing time is arbitrarily determined to produce T-fibers within the scope of the present invention, but is usually from 1 second to 10 hours.

delivery service EXAMPLES The present invention will be specifically explained below with reference to Examples.

(Examples 1 to 6) A three-dimensional orthogonal fabric was made using fibers obtained by melt-spinning carbonaceous pitch and subjecting the fibers to infusibility treatment to primary heat treatment at a temperature of 1700 to 2450°C. was subjected to a secondary heat treatment at 2500°C. Table 1 shows the evaluation of the obtained three-dimensional fabric.

(Comparative Examples 1 to 3) One-fire heat treatment shown in Table 1! This is 1 ton of three-dimensional orthogonal fabric using fibers! 25 (secondary heat treatment was performed at 10° C.) Evaluations of the obtained three-dimensional fabrics are also shown in Table 1.

Ωt] By the method of the present invention, it is possible to obtain a carbon fiber fabric with less fluff and no burning curls.

table

Claims (1)

[Claims] Obtained by melt-spinning carbonaceous pitch and performing a primary heat treatment on the infusible-treated fibers at a temperature above 650°C and below 2500°C, and has a tensile strength of 250 kgf/mm.
A two-dimensional or three-dimensional woven fabric is formed from the primary heat-treated fibers having an elongation of more than A method for producing carbon fiber fabric, which is characterized by performing a secondary heat treatment at a high temperature.