JPH0434086A - Carbon fiber and carbon fiber reinforced resin composition using the same carbon fiber - Google Patents

Abstract

PURPOSE:To obtain reinforcing carbon fibers extremely improving electrical conductivity between matrix resin and composite material, by coating the surface of carbon fibers with a copolymer comprising a diamine, a dicarboxylic acid, a cyclic amide and a specific ratio of a glycidylated polyalkylene oxide derivative. CONSTITUTION:A diamine compound [shown by formula I (R<3> is <=15C alkyl)] is copolymerized with a dicarboxylic acid compound [shown by formula II (R<4> is <=15C alkyl, etc.)], a cyclic amide [shown by formula III (R<5> is <=20C alkyl) and a glycidylated polyalkylene oxide derivative shown by formula IV (R<1> is H or <=20C alkyl; R<2> is H is methyl; n is 1-40) to give a sizing agent for carbon fibers, comprising a copolymer containing 10-30wt.% glycidylated polyalkylene oxide derivative as a monomer composition. The sizing agent is added to chopped strands, which are dried, blended with a matrix resin, especially acrylonitrile-butadiene styrene resin, etc., injection molded to give a resin reinforced with the carbon fibers having more extremely improved electrical conductivity than an existing carbon fiber reinforced resin.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application] The present invention relates to carbon fibers and carbon fiber reinforced resin compositions containing the carbon fibers.

[Prior art] In recent years, fiber-reinforced resin compositions made by mixing and dispersing carbon fibers in various matrix resins have been evaluated for their mechanical properties such as high strength, high rigidity, low specific gravity, and high abrasion resistance, and have been used industrially. It is attracting attention as an important material.

Further, in addition to carbon fiber's mechanical properties such as strength and elastic modulus, development of applications that utilize properties such as electrical conductivity, thermal conductivity, and X-ray transparency is also underway. Particularly in electronics-related fields, carbon fibers are often used as conductive composite materials that take advantage of the high conductivity of carbon fiber itself.

However, simply mixing and molding carbon fiber with resin does not provide sufficient electrical conductivity unless a large amount of carbon fiber is added. This generally limits the use of carbon fibers, as it can lead to increased costs for resin compounds due to the large use of carbon fibers, which are more expensive than resins, decreases in physical properties such as impact resistance, increases in specific gravity, and decreases in processability. Ta. In order to solve these problems, attempts have been made to improve conductivity. For example, in JP-A-57-56586, carbon fibers are coated with polyvinylpyrrolidone in an attempt to improve the conductivity of a composite material.

[Problem to be solved by the invention] However, depending on the application, it still cannot be said to have sufficient electrical conductivity, and there is a need to develop carbon fiber reinforced resin composite materials that have even better electrical conductivity than conventional composite materials. It was getting worse.

[Means for Solving the Problems] Therefore, as a result of intensive studies to solve the problems, the present inventors found that using carbon fiber coated with a polymer having a specific composition requires a smaller amount of compounding than before. It was discovered that a carbon fiber-reinforced resin exhibiting conductivity equivalent to that of conventional resin compositions can be obtained, and that higher conductivity than conventional resin compositions can be obtained by using the same amount as conventional resin compositions, and the present invention has been achieved.

That is, an object of the present invention is to provide a resin-reinforced carbon fiber that provides a resin composition that exhibits high conductivity, and a carbon fiber-reinforced resin composition using the same.

The eyelid is a copolymer consisting of a diamine compound, a dicarboxylic acid compound, a cyclic amide compound, and a glycidylated polyalkylene oxide derivative represented by the following general formula (I), in which the polyalkylene oxide derivative is used as a monomer composition. 10
Carbon fiber for resin reinforcement, characterized in that the surface of the carbon fiber is coated with a copolymer containing ~30% by weight (wherein R1 is Hl or an alkyl group having 20 or less carbon atoms,
R2 represents H or CH3, and n represents an integer of 1 to 40. ), a diamine compound, a dicarboxylic acid compound, a cyclic amide compound, and a glycidylated polyalkylene oxide derivative represented by the following general formula (I), the copolymer comprising a glycidylated polyalkylene oxide derivative having a monomer composition of 10
1 to 50 parts by weight of carbon fibers whose surfaces are coated with a copolymer containing 30% by weight of a thermoplastic resin
This can be easily achieved by using a carbon fiber reinforced resin composition characterized in that it is blended in parts by weight.

(In the formula, R1 is hydrogen or an alkyl group having 20 or less carbon atoms,
R2 represents H or CH3, and n represents an integer of 1 to 40. ) The present invention will be explained in detail below.

In the present invention, various conventionally known carbon fibers can be used as the carbon fibers, and specific examples include polyacrylonitrile-based, pitch-based, and rayon-based carbon fibers.

The polymer used for coating is a copolymer of a diamine compound, a dicarboxylic acid compound, a cyclic amide compound, and a glycidylated polyalkylene oxide. The diamine compound is not particularly limited, but compounds represented by the general formula (II), in which R3 is an alkyl group having 15 or less carbon atoms, and derivatives thereof are preferred. Specific examples include ethylenediamine, tetramethylenediamine, hexamethylenediamine, octamethylenediamine, decamethylenediamine, and derivatives thereof such as methylated, ethylated, and halogenated products.

The H2N R3-NH2(II) dicarboxylic acid compound is a compound represented by the general formula (III), and R4 preferably consists of an alkyl group having 15 or less carbon atoms, a mononuclear or dinuclear aromatic ring, and derivatives thereof. It is something. Specifically, conolic acid, glutaric acid, adipic acid, pimelic acid, speric acid, azelaic acid, sebacic acid and their methylated, ethylated, and halogenated derivatives, terephthalic acid, isophthalic acid,
, 6-naphthalene dicarboxylic acid and the like.

HOOC-R4-COOII (III) The cyclic amide compound is a compound represented by the general formula (IV), and R6 preferably consists of an alkyl group having 20 or less carbon atoms and a derivative thereof. Specific examples include caprolactam and lauryllactam.

The glycidylated polyalkylene oxide derivative represented by the general formula (I) is an aralkythyl addition reaction product of ethylene oxide and propylene oxide having a glycidyl group at one end, and n is 1 to 40, preferably 5 to 2.
0, R1 is an alkyl group having 20 or less carbon atoms, and R2 is H or CH3. Specific examples include polyoxyethylene lauryl glycidyl ether, polyoxyethylene octyl glycidyl ether, and the like.

The monomer composition ratio is determined within a range where the mixture is almost completely polymerized and a polymer with an appropriate molecular weight is obtained, but in order to obtain the effect of improving conductivity, the content of the glycidylated polyalkylene oxide derivative should be 10 to 30%. weight%.

It is preferably in the range of 15 to 25% by weight. If the content is too high or too low, it becomes difficult to obtain good conductivity.

Normally, carbon fibers are made by binding strands of several thousand to tens of thousands of single fibers together and covering them with resin to improve handling properties, or to improve properties when blended with resin to make a composite material.

Although there are no restrictions on the method of attaching the obtained polymer to the carbon fiber surface, a practical method is to impregnate the carbon fiber bundle with an aqueous solution. The concentration of the aqueous solution may be set so that the amount of polymer adhering to the carbon fibers is at a desired level. The amount of polymer attached to the carbon fibers is 0.5 to 20% by weight, preferably 2 to 10% by weight. If the amount of coating is small, the effect of improving the properties of the composite material by the sizing agent may not be observed, or the sizing agent may not have sufficient sizing ability. On the other hand, if the coating amount is too large, the physical properties of the composite material may deteriorate or the handling properties of the carbon fiber strands after convergence may deteriorate. The carbon fiber strand impregnated with the aqueous polymer solution is dried by infrared rays, hot air, etc., and the drying temperature is preferably 300° C. or lower to prevent decomposition of the sizing agent. The dried and bundled carbon fiber bundles are cut into lengths of 1 to 20 mm, preferably 3 to 10 mm, to facilitate blending with resin. (The cut carbon fiber strands are called chopped strands.)

Next, a carbon fiber-reinforced resin composition having excellent conductivity in which the resin-reinforcing carbon fiber of the present invention is blended with a thermoplastic resin will be described. Examples of matrix resins include polymers such as polycarbonate, polystyrene, polyester, polyolefin, acrylic resin, polyoxymethylene, polyphenylene ether, polyphenylene oxide, polybutylene leftate, polyether ether ketone, polyphenylene sulfone, and fluorine resin, or copolymers thereof. Examples include known thermoplastic resins such as
Preferably, acrylonitrile-butadiene-styrene resin (ABS resin), polybutylene terephthalate, and polyphenylene oxide are used.

The blending ratio of the above-mentioned resin-reinforcing carbon fibers and matrix resin is in the range of 1 to 50 parts by weight, preferably 5 to 40 parts by weight, per 100 parts by weight of the thermoplastic resin. If the amount of carbon fibers is less than 1 part by weight, the conductive effect of the carbon fibers will be low, and if it exceeds 50 parts by weight, various problems will likely occur during the mixing and dispersion process in the matrix resin.

Further, the method of blending such a matrix resin with the carbon fiber of the present invention is not particularly limited, but it can be conventionally used - a screw extruder, a twin screw extruder, a press machine, a high-speed mixer, an injection molding machine, a drawing machine, etc. This is done using a method such as a molding machine. Furthermore, in addition to the above-mentioned components, other short and long fibers such as carbon fibers, glass fibers, aramid fibers, poron fibers, silicon carbide fibers, whiskers, nickel, Fibers coated with metals such as aluminum and copper, or fibrous reinforcement materials such as metal fibers, or carbon black,
Reinforcing agents such as fillers such as molybdenum disulfide, mica, talc, and calcium carbonate, stabilizers, lubricants, and other additives can be added.

The carbon fiber-reinforced plastic resin composition thus obtained exhibits higher electrical conductivity than conventional carbon fiber-reinforced resin compositions.

[Example] Next, the present invention will be explained in more detail with reference to Examples. The conductivity evaluation is based on the Japan Rubber Institute Standards (SRIS) 2.
The measurement was carried out by measuring the volume resistivity as described in 301.

Example 1 (A) Preparation of sizing agent 25 parts by weight of hexamethylene diamine, 31 parts by weight of adipic acid, 24 parts by weight of caprolactam, and 20 parts by weight of polyoxyethylene lauryl glycidyl ether (molecular weight 700) were added and heated at 220°C after purging with nitrogen. These monomers were polymerized while heating and dehydrating to obtain a polymer. An aqueous solution of this polymer was prepared and used as a sizing agent solution for impregnating carbon fiber bundles.

(B) Production of chopped strands After impregnating 6,000 continuous filaments of pitch-based carbon fiber ('Dialead' K223, manufactured by Mitsubishi Kasei Corporation) into a 4% aqueous solution of the polymer, approximately 120
The mixture was dried by heating at °C for 20 minutes, and chopped strands with a length of 6 mm were produced using a cutting machine. The amount of polymer deposited on the obtained chopped strands is shown in Table 1 together with the results of Comparative Examples 1 to 5.

(C) Production of short carbon fiber reinforced resin molded article 1 dried in advance
0 parts by weight of the Chiyo Nobuto strands and polybutylene terephthalate resin "Tsunoku Douur" 5008 (
After tri-blending 100 parts by weight of pellets (manufactured by Mitsubishi Kasei Corporation), the mixture was put into a screw extruder, melt-mixed, and the extrudate was cooled with water and cut into pellets. The carbon fiber blended resin material thus obtained was heated to 120°C5.
After drying, it was molded using an injection molding machine to obtain a test piece, and its volume resistivity was measured. The measurement results are shown in Table 1 together with Comparative Examples 1 to 5.

Comparative Example 1 Polymerization was carried out in the same manner as in Example 1 using a seven-mer composition consisting of 29 parts by weight of hexamethylene diamine, 36 parts by weight of adipic acid, and 35 parts by weight of polyoxyethylene lauryl glycidyl ether (molecular weight 700), production of chopped strands, carbon A fiber-reinforced resin molded article was manufactured and its volume resistivity was measured.

Comparative example 2 α-(N.

Using an aqueous solution of N-dimethylamino)-ε-caprolactam polymer, chopped strands and carbon fiber reinforced resin molded articles were produced in the same manner as in Example 1, and the volume resistivity was measured.

Comparative Example 3 Instead of the sizing agent aqueous solution of Example 1, water emulsification of 60 parts by weight of epoxy resin 1'Evicor) 834 (manufactured by Shell Chemical ■) and 40 parts by weight of Epicoat 9.1004 (manufactured by Shell Chemical ■) A test piece was produced in the same manner as in Example 1 except that a sizing agent was used.

Comparative Example 4 A test piece was produced in the same manner as in Example 1, except that an aqueous solution sizing agent of polyvinylpyrrolidone (molecular weight 40,000) was used instead of the aqueous sizing agent solution in Example 1.

Comparative Example 5 A test piece was produced in the same manner as in Example 1, except that an aqueous solution sizing agent of polyethylene glycol (molecular weight 50,000) was used instead of the aqueous sizing agent solution in Example 1.

Example 2 A test piece was produced in the same manner as in Example 1, except that polycarbonate resin was used instead of the matrix resin polybutylene terephthalate of Example 1, and the amount of resin-coated carbon fiber was changed to 20 parts by weight. The measurement results of volume resistivity are shown in Table 3 together with Comparative Examples 6 to 10.

Comparative Examples 6-10 Comparative Examples 1-5 were used, except that the resin-coated carbon fibers used in Comparative Examples 1-5 were used, the matrix resin was changed from polybutylene terephthalate to polycarbonate resin, and the amount of resin-coated carbon fibers was 20 parts by weight. A test piece was manufactured in the same manner as above, and the volume resistivity was measured.

As shown in Table 1.2, when carbon fibers coated with a resin having the composition described in the claims of this patent are used, a resin composition having better conductivity than carbon fibers coated with other resins can be obtained.

Table 2 [Effects of the invention] The resin-coated carbon fibers of the present invention have the effect of significantly improving the conductivity of carbon fiber-reinforced thermoplastic resins compared to conventional carbon fibers, and have the effect of significantly improving the conductivity of carbon fiber-reinforced thermoplastic resins, as well as the fiber-reinforced resins containing the fibers. It is extremely useful industrially.

Claims (2)

[Claims] (1) A copolymer consisting of a diamine compound, a dicarboxylic acid compound, a cyclic amide compound, and a glycidylated polyalkylene oxide derivative represented by the following general formula (I), wherein the monomer composition of the polyalkylene oxide derivative is 10 to 30%. A carbon fiber characterized in that the surface of the carbon fiber is coated with a copolymer containing % by weight. ▲There are mathematical formulas, chemical formulas, tables, etc.▼(I) (In the formula, R^1 is hydrogen or an alkyl group having 20 or less carbon atoms, R^2 is hydrogen or a methyl group, and n is an integer from 1 to 40. .) (2) A copolymer consisting of a diamine compound, a dicarboxylic acid compound, a cyclic amide compound, and a glycidylated polyalkylene oxide derivative represented by the following general formula (I), wherein the monomer composition of the polyalkylene oxide derivative is 10 to 30%. 1. A carbon fiber-reinforced resin composition characterized in that 1 to 50 parts by weight of carbon fibers whose surfaces are coated with a copolymer containing % by weight are blended with 100 parts by weight of a thermoplastic resin. ▲There are mathematical formulas, chemical formulas, tables, etc.▼(I) (In the formula, R^1 is hydrogen or an alkyl group having 20 or less carbon atoms, R^2 is hydrogen or a methyl group, and n is an integer from 1 to 40. .)