JPS61197467A - Manufacture of carbon fiber reinforced composite material - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a simple method for manufacturing high performance carbon composite materials.

Prior Art and Problems to be Solved by the Invention Regarding a simple manufacturing method for high-performance carbon fiber reinforced carbon composite materials (hereinafter abbreviated as CFRC), the inventors have filed Japanese Patent Application No. 58-162433.
In addition, a new manufacturing method was disclosed in Japanese Patent Application No. 59-143844. These inventions relate to a method of mixing carbonaceous powder with a carrier resin, electrophoresing the mixture, depositing it on a carbon fiber base material using a deposition (electrodeposition) method, and molding and firing the mixture to obtain CFRC. It is.

In the above invention, since it is necessary to conduct electricity to the carbon fiber base material during electrodeposition, a two-dimensional base material such as carbon fiber woven fabric, paper, mat, or non-woven fabric is used as the form of the carbon fiber base material. , a method is described in which a one-dimensional base material such as string, filament thread, tape, etc. is used, and the material is formed by electrodeposition, laminated, wrapped, etc., and then fired. That is, in the methods of these inventions, short fiber base materials such as so-called chopped fibers and finely cut woven fabrics cannot be continuously energized, and the carbonaceous powder and carrier resin cannot be efficiently electrodeposited. It cannot be used because it cannot be done.

In order to coat such short fiber base materials, dip coating, etc., which does not require electricity, is used, but these methods do not provide sufficient adhesion to the base material, so it is difficult to coat them during subsequent mixing operations. There is a problem in that the base material and the coating layer are likely to separate and fall off.

However, CFR made by forming methods such as lamination method and winding method
C tends to cause anisotropy in tensile strength, bending strength, shear strength, and physical and mechanical properties.While there are some fields in which CFRC can be used to utilize anisotropy, structural materials etc. are reinforced in an iso-directional manner. There are many fields that require CFRC.

Means to Solve the Problem Electrodeposition is a method that can uniformly and firmly adhere carbonaceous powder to a base material in a desired ratio, and if this can be applied to a short fiber base material, electrodeposition will be used. CFRC with improved anisotropy can be made by randomly intertwining and mixing short fibers, shaping and firing. The conventional thinking was that electrodeposition was impossible because short fiber base materials could not be energized, but the inventors applied electrodeposition to a continuous base material while energizing it to adhere the carbonaceous powder and carrier. Then, it was cut into a desired length to obtain a short fiber base material coated with carbonaceous powder. In this case, there is a concern that the coating layer may separate from the base material due to the cutting operation, but since the coating layer made by electrodeposition has good adhesion to the base material, it is difficult to cut the coating layer as seen in coatings made by the usual dipping method. No significant shedding occurs.

It is possible to produce three-dimensionally reinforced CFRC by mixing the obtained coated short fiber base materials, randomly entangling them, forming and firing them. The content of the present invention will be described in more detail below.

Carbon fiber base materials as raw materials used in the present invention include strings made of bundled single fibers, filament yarns, woven fabrics, tapes, paper,
Mats etc. can be used. A carrier resin is attached to the finely divided carbonaceous powder and dispersed in a liquid to create a dispersion liquid.

In this case, additives such as sintering aids and inorganic powders such as ceramics can be added to the carbonaceous powder.

Thermoplastic and thermosetting resins that can be ionized in liquid can be used as carrier resins. Further, when mixing and dispersing the powder and resin, a dispersant and a surfactant may be used. Although it is easy to use water as the dispersion medium, it is also possible to use a non-aqueous medium depending on the purpose.

Next, a carbon fiber base material is immersed in the above-mentioned dispersion liquid, and a direct current voltage is applied to deposit the carbonaceous powder and carrier on the base material. This operation can be carried out by continuously feeding the base material or by batch processing.

Subsequently, the base material is pulled up from the liquid, and if necessary, subjected to treatments such as washing and dried, thereby obtaining a coated base material. When a thermosetting resin is used as a carrier, drying must be carried out at a temperature and time range that does not allow the curing reaction to proceed too much.

Thereafter, the coated base material is cut to an appropriate length or size, and a predetermined amount is placed in a mold and molded.

Conditions such as temperature and pressure during molding are adjusted to appropriate conditions depending on the properties of the resin, powder, and base material. At this stage, the molded body has a structure in which finely cut carbon fiber base materials are intricately intertwined, and the material is reinforced in random directions.

If the cutting length is less than III, the effect of entanglement will be small, and if it is more than 100+wa+, workability will be poor.

As for the shape of the molded product, it can be molded by filling it into a mold of any shape, and there are fewer restrictions on the shape compared to lamination methods, wrapping methods, etc., and molding can be done by ordinary compression molding or isostatic pressing. However, isostatic isostatic pressing is particularly preferable when the purpose is an isotropic molded product.The molded product is carbonized after being subjected to treatments such as infusibility, hardening, annealing, and removal of binders as necessary. It is fired to become CFRC.

The firing temperature is selected depending on the intended use of the material, but in order to obtain good strength, a temperature of 700 to 2000°C is appropriate.

In the case of graphitization, a high-density fired body can be obtained by further firing at 2000° C. to 3000° C. and firing while applying pressure during firing. The pressurization method is selected from compression pressurization, isostatic pressure pressurization, atmospheric pressurization, etc. depending on the purpose.

Example Examples will be explained below.

Example 1 (1) Self-sintering carbonaceous powder and calcined coke powder were mixed at a ratio of 1:1 to give an average particle size of 5 μm.

(n) After thoroughly kneading the above powder with a polyacrylonidol-acrylic acid electrodeposition resin and a solvent, dispersing it in water,
It was in the state of a so-called anionic paint dispersion. In this state, the ratio of carbon powder to resin was 1:1 by weight.

(DI) Next, a PAN-based carbon fiber filament yarn was prepared, and it was continuously supplied and immersed in the dispersion liquid, and at the same time, a voltage of 150 V was applied between it and a stainless steel plate used as a counter electrode, using the carbon fiber as an anode. Electrodeposition was carried out by applying electricity while stirring well. The yarn after electrodeposition is passed through a dryer and dried in an atmosphere of 80°C.

After drying, the weight ratio of the substrate to the electrodeposited material was 1:1.5.

(IV) The electrodeposited base yarn was cut into a length of 3 to 10 m to obtain a coated fiber, and the coated fiber was filled into a mold and pressed at a temperature of 200°C and a surface pressure of 20 kg/cd for 10 minutes. Molded.

(V) After this, while clamping under a pressure of 20kir/-, at each temperature of 250℃ and 280℃ in air,
It was heated for an hour to make it infusible.

(VT) This cured product was heated at 200 kg/a in an inert atmosphere.
1000℃ at a heating rate of 30℃/11r under JO surface pressure
200°C at a heating rate of 10r.
The temperature was raised to 0'C, held at 2000C for 1 hour, and then cooled to room temperature to obtain a CFRC. The final shape of the CFRC was a cylinder with a diameter of 50fi and a thickness of 40mm.

Comparative Example 1 (1) An electrodepositing dispersion using the same powder composition and resin as in Example 1 was used, and a woven fabric using carbon fiber of the same quality as the filament yarn of Example 1 was used as the base material. The electrodeposition conditions were adjusted so that the weight ratio of the woven fabric and the electrodeposited material after drying was the same as in Example 1, t:t, 5.

(n) 80 sheets of the obtained coated carbon fiber woven fabric were laminated and pressure-molded in a compression press at a temperature of 150°C and a surface pressure of 150° and +r/d for 20 minutes, and then infusible in the same manner as in Example 1. and pressure firing to produce a CFRC with the same shape as in Example 1.
And so.

Example 2 A coated fiber was made in the same manner as in Example 1, and heated at 200°C.
Static pressure molding was carried out at a pressure of 201qr10J. Thereafter, it was heated in air at 250°C and 280°C for 4 hours each to make it infusible. This was subjected to hot isostatic pressing at a heating rate of 30°C/Hr for 10
00℃, then 100℃ in an inert atmosphere at normal pressure.
The temperature was raised to 2000 °C at a temperature increase rate of °C/Hr.
It was held at ℃ for 1 hour and fired. The final shape was a CFRC having the same shape as in Example 1.

Table 1 shows the results of measuring the density and bending strength of the above Examples and Comparative Examples.

Chapter 1 Table (Note) In terms of bending strength A: A bending load is applied in the same direction as the pressure direction when forming a sieve.

However, in Example 2, the direction was the same as in Example 1 in terms of shape.

(Conducted with span 30mm, thickness 311II) BA
A bending load was applied in the direction perpendicular to A.

As shown above, in the methods of Examples 1 and 2, the strength anisotropy is significantly reduced compared to Comparative Example 1, and the workability during manufacturing does not require complicated operations such as lamination. Much improved.

Example 3 CFRC was manufactured through the same process as Example 1 using carbon fiber tape as the base material, and the density was 1.65.
, Bending strength A: 90MPa, B: 70MPa
Met.

Example 4 CFRC was produced in the same manner as in Example 1 except that a modified phenolic resin was used as the electrodepositing resin, and the density was 1.7 and the bending strength A: 90 M Pa, B
: It was 75M Pa.

Effects of the Invention As shown above, according to the present invention, a carbon fiber reinforced composite material having excellent mechanical strength with well-balanced strength in each direction and strong adhesion between each layer can be easily and inexpensively produced. .

Procedural amendment dated October 1985], Mr. Michibu Uga, Commissioner of the Japan Patent Office1, Indication of the case, 1985 Patent Application No. 0350502, Name of the invention:
1) How to manufacture carbon fiber reinforced composite materials]
゛3.Relationship with the case of the person making the amendment Patent application address
5-15 Kitahama, Higashi-ku, Osaka Name (213) President: Tetsu Kawakami Department 4, Sumitomo Electric Industries, Ltd. Address: 6, Sumitomo Electric Industries, Ltd., 1-1-3 Shimaya, Konohana-ku, Osaka In the subject specification, column 7 of the detailed description of the invention, content of amendment (1) "Polyacrylonitrile" in the second line from the bottom of page 7 of the specification is corrected to "polyacrylonitrile".

Claims (5)

[Claims] (1) After attaching a carrier that can be ionized in a liquid to carbonaceous fine powder, it is dispersed in the liquid to form a dispersion liquid, and a carbon fiber base material is immersed in the dispersion liquid, and the base material and the counter electrode are A DC voltage is applied during the process to deposit the carbonaceous powder and the carrier on the carbon fiber base material to obtain a coating in which the carbon fibers are coated with the carbonaceous powder and the carrier. 1. A method for producing a carbon fiber reinforced composite material, which comprises cutting the material into lengths, filling the cut coating into a mold, molding and firing. (2) The carbon fiber reinforced composite material according to claim 1, wherein the carbon fiber base material is a string or thread-like material made of bundled single fibers, or a woven fabric, paper, or nonwoven fabric. Production method. (3) The method for manufacturing a carbon fiber reinforced composite material according to claim 1 or 2, characterized in that pressure forming and pressure firing are performed in the molding and firing steps. (4) The method for manufacturing a carbon fiber reinforced composite material according to claim 1 or 2, characterized in that isostatic pressure forming and isostatic pressure firing are performed in the molding and firing steps. (5) Production of a carbon fiber reinforced composite material according to claim 1, 2, 3 or 4, wherein the carrier is a polyacrylonitrile resin derivative or a thermosetting resin. Method.