KR880002437B1 - Carbon fiber making method - Google Patents

Abstract

A mixture is prepared to comprise glycidyl amine group epoxy resin 50-85 wt. parts, cresol novolac epoxy resin 10-25 wt. parts, bisphenol A group epoxy resin 5-25 wt. parts, hardener 20-50 wt. parts and a hardening accelerator 0.5-3 wt. parts. The mixture is heat-melted into a uniform solution to impregnate carbon fibres, and it is controlled to flow at the rate of 1.5% to form a unidirectionally aligned heat-resistant carbon fibre reinforced plastic material.

Description

Manufacturing method of heat resistant carbon fiber molding material

The present invention relates to a method for producing a carbon fiber reinforced molding material having high heat resistance, excellent mechanical properties, and suitable for producing a homogeneous composite material.

Glass fibers including carbon fibers, aromatic polyamide fibers, and silicon carbide fibers are light and have excellent mechanical properties, but the fibers themselves are difficult to use as structural materials. Therefore, thermosetting resins such as epoxy resins, phenol resins, unsaturated polyester resins, and vinyl ester resins, and thermoplastic materials such as polybutylene terephthalate, polyphenylene sulfide, polycarbonate, polyether, and ether ketone are used as matrices. Used in a form that complements the resin's vulnerability. At this time, it is a sex energy material for transportation equipment related fields such as aircraft and space equipment that needs light weight, fatigue resistance and high strength of molded composite material, and it is a component of industrial machinery field that needs high strength, light weight, dimensional stability, etc. It is also widely used for high-end sporting goods such as fishing rods, rackets and golf shafts.

In order to manufacture such a composite material, it is used through the form of molding materials such as unidirectional array prepreg, woven prepreg, and brate prepreg. In particular, the structure of the carbon fiber-reinforced composite material has excellent adhesiveness with fibers and heat resistance. The one-way array prepreg in which the reinforcing material is arranged in one direction is most commonly used as a molding material so that an epoxy resin having excellent processing characteristics compared to other matrix resins can be used most efficiently to use the excellent mechanical performance of the reinforcing fiber.

In order to form a plate-like precision machine part or an aircraft structural material by using such a molding material, a sheet-like molding material is laminated to a required thickness in a product, and then a release film and a balloid material as a resin absorbing layer are stacked thereon and nylon , Which is manufactured by covering a heat-resistant plastic film such as polyimide, and then molding by applying vacuum pressure and hot air pressure. Is discharged to the outside of the material is absorbed in the resin, the bolide, and the remaining resin acts as a base material (matrix) to support the reinforcing fibers to exhibit the inherent physical properties of the composite material.

Conventionally, the method used to remove 3-5% of the resin generated in the curing reaction of the resin out of the body and to promote adhesion between the layers by flowing about 3-5% of the resin during the Seoyoung Yeong composite material, but to control the amount of the resin outflow It is difficult to do this, and therefore, it is difficult to manufacture a product having a uniform physical properties and dimensions of the molded product.

The present inventors have made intensive studies on the method of manufacturing a carbon fiber-reinforced molding material capable of producing a uniform composite material.

That is, a one-component epoxy resin mixture made by using tetraglycidyl diamino diphenyl metal, a polyfunctional epoxy resin represented by the following formula as a main component, and a resin in which an imidazole-based curing accelerator is blended in a solvent-free phase is heated and melted. The molding material obtained by impregnating carbon fiber in the state was able to produce a heat-resistant carbon fiber molding material capable of producing a homogeneous composite material because the flow rate of resin during molding was less than 1.5%, and heat resistance and adhesion were excellent.

The present invention is 50-80 parts by weight of glycidyl amine epoxy resin, 10-25 parts by weight of cresol novolac epoxy resin, 5-25 parts by weight of bisphenol A-based epoxy resin, 20-50 parts by weight of a curing agent and a curing accelerator 0.5-3 parts After mixing the parts by weight to prepare a resin mixture, the present invention relates to a method for producing a one-way array, heat-resistant carbon fiber molding material, characterized in that to control the flow of the resin within 1.5%.

Examples of the epoxy resin used in the present invention include polyfunctional epoxy resins such as MY-720 (CIBA-GELGY), ELM0120 (SUMITOME CHEM), M-3000 (MAKHTESHIM), EPOTOTO-YH434 (Dongdo Chemical), etc. Cresol novolac-based ECN 1180, 1299 (CIBA-GEIGY), phenol novolac-based EPN 1138 (CIBA-GEIGY), DEN 431, DEN 438, DEN 439 (DOW CHEMICAL), EPIKOTE 152, EPIKOTE 154 (SHELL CHEMICAL CO., LTD.).

Examples of bisphenol A system include ARALDITE GY 252, GY255, GY250, GY260, ARALDITE 6071, ARALDITE 7071, ARALDITE 7072 (CIBA-GEIGY), EPIKOTE 828, EPIKOTE 827, EPIKOTE 834, EPIKOTE 1001, EPIKOTE 1002, EPIKOTE 1004, EPILOTE 1007 (SHELL CHEMICAL), YD-115, YD-117, YD-121, YD-127, YD-128, YD-134, YD-001, YD-012, YD-014, YD-017, YD- 019, YD-020 (Kukdo Chemical Co., Ltd.), etc. are mentioned.

The present invention uses a diamino diphenyl sulfone, dicyandi diamide mixed curing agent and an imidazole-based accelerator in the tetrafunctional epoxy resin, the amount of the curing agent is used 20-50 parts by weight based on 100 parts by weight of the total amount of resin, It is preferable to use 18-40 parts by weight of diamino diphenylsulfone and 2-10 parts by weight of dicyandi diamide.

In order to improve adhesion between materials in the state of low flow of resin during molding of molding materials, 10-25 parts by weight of cresol-based epoxy resin having high heat resistance and high adhesion, preferably 15-25 parts by weight, can be used without reducing heat resistance. Can improve.

In addition, the adhesion between the molding materials is improved by using the bisphenol A epoxy resin within 5-25 parts by weight, preferably 10-20 parts by weight, within the range of not deteriorating the heat resistance and the mechanical properties, which are the objects of the present invention. When the bisphenol-based epoxy resin is used at 5 parts by weight or less, a synergistic effect of the adhesive force cannot be expected, and when 25 weight or more is used, the heat resistance is lowered.

The imidazole series curing accelerator used in the present invention is, for example, 2-methylimidazole, 2-ethyl imidazole, 2-isopropyl imidazole, 2-heptadecyl imidazole, 2-undenyl imidazole, 2-phenyl Imidazole, 1-benzyl-2-methyl imidazole, 1-cyano ethyl-2-imidazole, 1-cyano ethyl-2-isopropyl imidazole, 1-cyano ethyl-2-methyl-4-methyl Imidazole, 1-cyano ethyl-2-phenyl imidazole, 2-ethyl-4-phenyl imidazole, 2-methyl-5-ethyl imidazole, 2,5-dichloro-4-ethyl imidazole, benzo imidazole And liquids at room temperature, for example 2-ethyl-4-methyl imidazole, 1-cyano ethyl-2-ethyl-4-methyl imidazole, 1-benzyl-2-methyl imidazole and the like. good.

The amount of the imidazole compound is usually 0.1 to 5 parts by weight, preferably 1.0 to 2.5 parts by weight of the epoxy resin can be used to suppress the resin flow. However, when the amount of imidazole, which is a curing accelerator, is used in an amount of 0.1 parts by weight or less, there is no effect of suppressing the flow of the resin, and when 5 parts by weight or more is used, the adhesion between the molding materials becomes worse and the overall physical properties of the final molding are lowered. .

The content of the present invention will be described in detail with reference to the following examples.

Example 1

Tetra glycidyl diamino diphenylmethane (manufactured by MY 720 CIBA-GEIGY) 60 parts by weight, cresol novolac epoxy (manufactured by ECN 1299 CIBA-GEIGY) 15 parts by weight, bisphenol A-based epoxy (made by ARALDITE GY 260 CIBA-GEIGY) ) 25 parts by weight, 33 parts by weight of diamino diphenyl sulfone, 2 parts by weight of dicyandiamide, and 1.0 part by weight of 1-cyano ethyl-2-4-methyl imidazole were heated and stirred and mixed in a vacuum stirrer to prepare an epoxy mixture. Prepared. The prepared mixture was applied on a release paper by passing between rollers of roller cotta fixed at 70-90 ° C., and the roller heated to 150 ° C. by uniformly arranging carbon fiber Toraya T-300 (manufactured by Toray Corporation) in one direction. A one-way array carbon fiber molding material having a resin content of 365 was prepared by passing through. This molding material is cut into 400mm in the fiber length direction and 100m in the width direction, and two pore-containing synthetic resin films that can be released on both sides are attached to each other, and then vacuum-covered with nylon film, and then heated to 175 ° C. Pressurized and heat-molded at 7Kg / cm <^2> for 3 hours, and the hardened | cured material of 1.2 mm was obtained.

The flow rate of resin during the molding process was measured according to ASTM D 3531, and the tensile strength and elastic modulus, flexural strength and elastic modulus, and interlaminar shear strength of the molded composite material were measured.

Example 2

MY 720 (manufactured by CIBA-GELGY), 70 parts by weight, 10 parts by weight of ECN 1299 (manufactured by CIBA-GEIGY), 20 parts by weight of GY 260, 25 parts by weight of diamino diphenyl methane, 3.0 parts by weight of dicyandiamide, 2- 1.5 parts by weight of ethyl-4-methyl imidazole was mixed into the fixing holes to prepare a unidirectionally arranged carbon fiber molding material having a resin content of 36%. Physical properties of the composite material molded in the same manner as in Example 1 are as follows.

Example 3

MY 720 (manufactured by CIBA-GELGY), 75 parts by weight, 25 parts by weight of GY 260 (manufactured by CIBA-GEIGY), 35 parts by weight of diamino diphenylsulfone, 2.0 parts by weight of dicyandiamide, 2-ethyl-4-methyl imi 1.0 part by weight of the doazole was mixed in the same manner as in Example (1) to prepare a unidirectionally arranged carbon fiber molding material having a resin content of 36%. Physical properties of the composite material molded in the same manner as in Example (1) are as follows.

Example 4

The interlaminar shear strength and the flow rate of the resin of the composite material obtained by heating the molded material prepared in Example (1) at a relatively low pressure of 4.5 Kg / cm ² in an autoclave molding machine heated to 175 ° C were almost the same.

Comparative Example 1

100 parts by weight of MY 720 (manufactured by CIBA-GELGY), 44 parts by weight of diamino diphenyl sulfone were mixed in a reduced pressure container to prepare a unidirectionally arranged carbon fiber molding material having a resin content of 36% by the same method as in Example (1). It was. The physical properties of the composite material formed by molding the prepared molding material in the same manner as in Example (1) had a high resin flow rate, and the interlayer adhesion strength and flexural strength were lowered.

Comparative Example 2

The physical properties of the composite material molded by the same process as in Example 3 using a molding material prepared by mixing MY 720 (manufactured by CIBA-GELGY), 100 parts by weight, and 44 parts by weight of diamino diphenyl sulfone are as follows.

Claims (3)

50-80 parts by weight of glycidyl amine epoxy resin, 10-25 parts by weight of cresol novolac epoxy resin, 5-25 parts by weight of bisphenol A epoxy resin, 20-50 parts by weight of curing agent and 0.5-3 parts by weight of curing accelerator The method for producing a one-way array heat-resistant carbon fiber molding material, characterized in that the resin mixture is prepared, and then the flow of the resin is controlled to within 1.5%. The process of claim 1 wherein the curing agent consists of 18-40 parts by weight of diamino diphenyl sulfone and 2-10 parts by weight of dicyandiamide, based on the entirety of the curing agent. The method according to claim 1, wherein the curing accelerator is an imidazole compound selected from the group consisting of 2-ethyl-4-methyl imidazole and 1-cyanoethyl-2,4-methyl imidazole.