JPH0137516B2 - - Google Patents

Description

[Detailed description of the invention]

[Industrial Application Field] The present invention relates to a flexible carbon fiber cord that can be easily twisted and twisted and does not cause cord cracking, and a method for manufacturing the same. More specifically, it is a flexible carbon fiber cord made by binding carbon fiber bundles with a reaction product of a butadiene-acrylonitrile copolymer (hereinafter referred to as "CTBN") having carboxyl groups at both ends and an epoxy resin. and its manufacturing method. The carbon fiber cord is used for cables and the like in offshore development or industry. [Prior art] Carbon fiber has excellent properties such as high specific strength, specific modulus, fatigue resistance, and heat resistance, so it is used in space and other applications.
It has been widely used in aviation, automobile, sports and leisure fields, etc. However, carbon fibers with the above-mentioned characteristics also
Because the fiber diameter is small and brittle, it is rarely used alone; in most cases, it is shaped and solidified using a synthetic resin or the like as a matrix and used in a rigid state. Materials formed in this manner are inflexible and very hard, and are generally used in fields where little deformation is required. On the other hand, if cords made of organic fibers such as nylon or polyester fiber bundles or cords with flexibility similar to those found in ropes can be obtained using carbon fiber bundles, high Cords, ropes, etc. with high performance have been realized,
This product can be expected to be used as cables for offshore development or construction work. However, carbon fiber bundles have the disadvantage of low workability due to their characteristic high elastic modulus, and are susceptible to problems such as buckling and cord cracking. For this reason, the original characteristics of carbon fiber bundles are not fully exhibited, making it difficult to develop applications in this field. [Structure and Effects of the Invention] The present inventors have studied a carbon fiber cord that does not have such problems and has excellent workability and flexibility, and as a result, has arrived at the present invention. That is, in the present invention, carbon fiber bundles are bundled in a matrix containing 5 to 50% by weight of a reaction product of CTBN (butadiene-acrylonitrile copolymer having carboxyl groups at both ends) and an epoxy resin as a resin component. It is a carbon fiber cord with flexibility. The present invention also provides a method for producing such a cord, which includes a resin component of 5 to 50% by weight (based on carbon fibers) consisting of a preliminary reaction product of CTBN and an epoxy resin or a mixture thereof, and an epoxy resin curing agent. This method is characterized in that carbon fiber bundles are applied and impregnated, and then heat treated to harden the resin component. The carbon fiber cord of the present invention has good convergence,
The cord does not crack even after repeated bending, has excellent workability, and exhibits particularly high knot strength. Here, the carbon fiber bundle is a multifilament or interlaced bundle of 1,000 to 30,000 monofilaments with a diameter of 4 to 20 μm. Such carbon fiber bundles are classified into polyacrylonitrile type, rayon type, pitch type, etc. depending on the type of raw material precursor, but in the present invention, there is no particular restriction, and commonly used fibers can be used. As the CTBN, for example, Hiker CTBN manufactured by Gutsudoritsu Co., Ltd. is used. The epoxy resin is not particularly limited, and bisphenol A type epoxy resin, such as Epicote 828,
Epicote 834 (all manufactured by Ciel Chemical),
DER332 (manufactured by Dow Chemical Company), and glycidylamine type epoxy resins, such as MY-720 (manufactured by Ciba Geigy Company), Epotote YH434 (manufactured by Toto Kasei Company)
etc. are suitable. As an epoxy resin curing agent,
Those commonly used can be applied. In particular, imidazole-based and polyamide-based curing agents are suitable because the curing reaction is completed in a short time. in particular,
As an imidazole curing agent, for example, 2-ethyl-
Examples of polyamide curing agents such as 4-methylimidazole include Tomide (manufactured by Fuji Kasei Kogyo Co., Ltd.),
Versamide (manufactured by Daiichi General Co., Ltd.) and the like are used. A matrix whose resin component is a reaction product of CTBN and an epoxy resin, etc. is obtained by reaction-curing a pre-reaction product of CTBN and an epoxy resin or a mixture thereof on a carbon fiber bundle. It is added in an amount of 5 to 50% by weight.
Particularly preferably 10 to 30% by weight. Strand prepreg is known as a carbon fiber bundle with a resin component added to it, but in strand prepreg, the resin that becomes the matrix is not hardened, and it is difficult to harden the matrix resin by heating etc. after shaping. In contrast, the carbon fiber cord of the present invention has a hardened matrix and is flexible, so it has good form stability and workability, can be processed into textiles, braids, etc., and does not buckle. do not have. A viscosity modifier, a conductivity improver, a coloring agent, etc. can also be added as a third component to be attached to or impregnated into the cord of the present invention. The resin component is preferably a reaction product of 100 parts by weight of CTBN and 5 to 6 parts by weight, particularly preferably 10 to 40 parts by weight of an epoxy resin. When the amount of epoxy resin increases, the cord becomes more likely to crack, buckle, and break at the buckling point during processing. The method for manufacturing the carbon fiber cord of the present invention will be described. (Preparation of resin component) CTBN and epoxy resin are pre-reacted and then applied to and impregnated into the fiber bundle, or a mixture of CTBN and epoxy resin is applied and impregnated into the fiber bundle.
The preliminary reaction between CTBN and epoxy resin is, for example,
It is carried out under stirring at 110-120°C for 1-2 hours. Usually triphenylphosphine is used as a reaction catalyst. An epoxy resin curing agent is added to the pre-reactant or mixture. The amount of curing agent is usually determined based on the total weight of epoxy resin and CTBN, for example, in the case of 2-ethyl-4-methylimidazole.
0.1-2% by weight, 3-50 for Tomide 215X
It is used in a range of % by weight. (Applying and impregnating the fiber bundle with the resin component) The resin component is dissolved in a single solution or a mixture of organic solvents such as acetone, methyl ethyl ketone, or methyl cellosolve to make a homogeneous solution, and the solution is applied by dipping method, spray method, or drum contact method. etc. to impregnate the fiber bundle. The solution concentration varies depending on the impregnation method, but approximately 20% by weight is appropriate. Although the temperature of the solution is preferably lower for reasons such as solution stability and concentration stability, it is usually used in a range of 10 to 30°C. Solvent removal is preferably carried out at 80 to 150°C. (Heat treatment) Curing of matrix resin consisting of CTBN and epoxy resin varies depending on the type of epoxy resin curing agent, etc., but it is usually heat treated at 150 to 230°C for 1 to 30 minutes, especially in a non-contact state. good. If the cord is cured in a contact state, the cord will become flattened, which is not preferable. It is preferable to perform the heat treatment after complete solvent removal in order to prevent the generation of voids inside the cord and the generation of blisters on the surface. This heat treatment cures the epoxy resin and completes the reaction between CTBN and the epoxy resin, and as a result, the resin becomes insoluble in the solvent before the reaction, such as methyl ethyl ketone. The carbon fiber cord of the present invention produced as described above is a cord that is well bundled, hardly causes cord cracking, and has excellent mechanical properties such as strength and elastic modulus. It has particularly excellent flexibility and high knot strength. The carbon fiber cord of the present invention can be used alone or in combination or by twisting a plurality of cords. [Example] Example 1 Butadiene having carboxyl groups at both ends
Acrylonitrile copolymer Hycar CTBN1300×
13 (manufactured by Gutsudoritsuchi) and 20 parts by weight of glycidylamine type epoxy resin MY-720 (manufactured by Ciba Geigy) were mixed and preliminarily reacted at 110°C for 2 hours. Subsequently, this pre-reacted resin was dissolved in methyl ethyl ketone so that the resin concentration was 20% by weight. Furthermore, MY-720,
3 parts by weight of the curing agent 2-ethyl-4-methylimidazole was added to 100 parts by weight and thoroughly stirred and mixed. Next, a carbon fiber bundle (Besphite HTA-7-6000 manufactured by Toho Rayon Co., Ltd.) was continuously impregnated with this resin solution, dried at 120°C for 3 minutes, and cured at 200°C for 2 minutes. The resin adhesion amount of the obtained carbon fiber bundle cord was 23.5
It was in weight%. This carbon fiber cord was very pliable, had good convergence, and was highly flexible. The flexibility of the obtained cord was evaluated by knot strength. Measurements were made using an Instron testing machine at a tensile speed of 50
mm/min, and the load at the time of rupture at the nodule was read. As a result, the nodule strength was 8.3Kg. Example 2 0.4 g of triphenylphosphine was added as a pre-reaction catalyst to 100 parts by weight of Hycar CTBN 1300×13, 20 parts by weight of bisphenol A type epoxy resin, Epicoat 828 (manufactured by Ciel Chemical Co., Ltd.), and the mixture was heated at 120°C for 2 hours. A preliminary reaction was carried out. This preliminary reaction product is dissolved in a mixed solvent of methyl ethyl ketone and methyl cellosolve, and then polyamide resin Tomide is added as a hardening agent.
215X (manufactured by Fuji Kasei Kogyo Co., Ltd.) was added in the same amount as Epicote 828 to prepare a 20% by weight resin solution. The same carbon fiber bundle as in Example 1 was used, and impregnation, drying, and curing were performed in the same manner as in Example 1 to produce a carbon fiber cord. This cord was very pliable, had good convergence, and was highly flexible. The resin adhesion amount of this cord is 20.3% by weight,
In addition, nodule strength was measured in the same manner as in Example 1.
It weighed 9.5Kg. Example 3 A resin mixture with different mixing ratios of Hycar CRBN 1300×13 and MY-720 was prepared, and the resin concentration was 20% by weight in methyl ethyl ketone without pre-reaction.
Furthermore, 2-ethyl-4-methylimidazole was added as a hardening agent to this resin solution.
3 parts by weight were added to 100 parts by weight of MY-720 and mixed by thorough stirring. Next, the same carbon fiber bundle as in Example 1 was impregnated with these resin solutions in the same manner as in Example 1, and dried and hardened to produce a carbon fiber cord. The performance of the obtained carbon fiber cord was as shown in the table below.

[Table] (Note): Example of the present invention As shown above, it can be seen that as the ratio of epoxy resin to CTBN increases, the cord becomes harder and more brittle.

Claims (1)

[Scope of Claims] 1 Carbon fiber bundles can be bundled in a matrix containing 5 to 50% by weight of a resin component of a reaction product of a butadiene-acrylonitrile copolymer having carboxyl groups at both ends and an epoxy resin. Flexible carbon fiber cord. 2. The flexible carbon fiber cord according to claim 1, wherein the resin component is a reaction product of 100 parts by weight of a butadiene-acrylonitrile copolymer having carboxyl groups at both ends and 5 to 60 parts by weight of an epoxy resin. 3 Resin component 5 to 50 consisting of a preliminary reaction product of a butadiene-acrylonitrile copolymer having carboxyl groups at both ends and an epoxy resin or a mixture thereof
% by weight (based on carbon fibers) and an epoxy resin curing agent is applied to and impregnated into a carbon fiber bundle, and then heat-treated to harden the resin component. . 4. The flexible carbon according to claim 3, wherein the resin component is a preliminary reaction product or a mixture of 100 parts by weight of a butadiene-acrylonitrile copolymer having carboxyl groups at both ends and 5 to 60 parts by weight of an epoxy resin. Method of manufacturing fiber cord.