JP2013208724A - Molding intermediate material using thick carbon fiber - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a carbon fiber-reinforced composite material obtained by impregnating a carbon fiber bundle with a thermosetting resin or a thermoplastic resin, reducing voids and having well-balanced mechanical characteristics and molding fluidity to improve impregnating ability of a matrix resin, and thus provide a fiber reinforced molding member reinforced with carbon fibers excellent in a property to be shaped by a molding die when molded.SOLUTION: A resin-reinforced material including carbon fibers having a single fiber fineness of 1.0-2.4 dtex is provided. Preferably, a circularity of a single fiber of the carbon fiber is 0.70-0.90, the carbon fibers of 10-90 mass% are included, and a length of the carbon fiber is 1-60 mm.

Description

  The present invention relates to the shape and composition of carbon fibers used for a resin molding material excellent in processability, in which carbon fibers are impregnated with a thermosetting resin or a thermoplastic resin.

  Conventionally, in order to impregnate a carbon fiber with a thermoplastic resin or a thermosetting resin, a press or reaction at a high temperature and a high pressure has been required. In particular, in a plastic resin, when heated and melted, the viscosity is high and the fluidity is poor. Therefore, it is difficult to form a uniform matrix by entering between the carbon fibers, and voids are easily generated.

  A fiber having a large single fiber degree has a lower viscosity resistance than that of a conventional material when impregnated with a resin, has high fluidity, has less voids in the material, and can be expected to have high physical properties. Further, when a product formed into a plate shape or a mat shape is subjected to compression processing in a mold, there is a tendency that resistance to movement and deformation of the fiber is low, and the degree of freedom of processing is increased.

JP 2011-157524 A

  The present invention provides a carbon fiber reinforced composite material in which a carbon fiber bundle is impregnated with a thermosetting resin or a thermoplastic resin and has few voids and has an excellent balance between high mechanical properties and molding fluidity.

  The present invention is a resin reinforcing material made of carbon fibers having a single fiber density of 1.0 dtex to 2.4 dtex.

  According to the present invention, a carbon fiber having a single fiber fineness of 1.0 dtex to 2.4 dtex and a roundness of 0.70 or more and 0.90 or less in producing a carbon fiber reinforced composite material excellent in processability and the like. A carbon fiber composite material excellent in workability and physical strength is manufactured by impregnating a thermosetting resin or a thermoplastic resin with the bundle.

  The carbon fiber reinforced composite material produced according to the present invention refers to a molded body containing at least two types of carbon fiber and a thermoplastic resin serving as a matrix resin. The carbon fiber used in the present invention is a glass fiber, carbon fiber, metal fiber, aromatic polyamide fiber, polyaramid fiber, alumina fiber, silicon carbide fiber, boron fiber, and the like, which are used in combination with high strength, high elasticity fiber. Two or more kinds may be mixed.

  Carbon fiber is essential for the effect of imparting mechanical properties, and surface treatment, coupling agent, and sizing agent can be applied to the surface of the carbon fiber bundle in advance.

  As a kind of the thermosetting resin used as the matrix in the present invention, urethane resin, melamine resin, urea resin, thermosetting acrylic resin, phenol resin, epoxy resin, thermosetting polyester resin and the like are suitable.

  The type of thermoplastic resin is not particularly limited, but a thermoplastic resin that is excellent in impact resistance and easy to mold is preferable. Examples of such thermoplastic resins include polyesters such as polyethylene terephthalate, polybutylene terephthalate, and liquid crystal polyester, polyolefins such as polyethylene, polypropylene, and polybutylene, polyoxymethylene, polyamide, polycarbonate, polymethylene methacrylate, and polyvinyl chloride. , Polyphenylene sulfide, polyphenylene ether, polyimide, polyamideimide, polyetherimide, polysulfone, polyethersulfone, polyetherketone, polyetheretherketone, phenol (novolak type), and their copolymers, modified products, and 2 Examples include resins blended in more than one type. Further, in order to further improve the impact resistance, an elastomer or a resin in which a rubber component is added to the above resin may be used.

  The molding method as a composite material is not particularly limited as long as the shape can be molded.

Hereinafter, preferred embodiments of the present invention will be described.
"In the case of thermosetting resin matrix"
The carbon fiber bundle used has a single fiber density of 1.0 dtex to 2.4 dtex and a length of 1 to 60 mm, preferably 5 to 40 mm, and more preferably 15 to 35 mm. The shape is processed into tape, prepreg, and chop and is easy to handle. Conventionally, methods for processing a carbon fiber bundle include a papermaking method, a drawing method, a pressing method, and the like, and there is no particular limitation as long as performance and shape can be achieved. In a state where 10 to 90 parts by mass of the carbon fiber bundle is dispersed as uniformly as possible in the mold, 10 to 90 parts by mass of the resin is supplied into the mold and reacted. The heating conditions vary depending on the type of the matrix resin, but are generally about 200 degrees Celsius. After the curing reaction has sufficiently progressed, the product is cooled, the mold is opened, and the product is taken out. In this case, the taken-out product may be an intermediate material used in a subsequent process or may be a final product shape.

"In case of thermoplastic resin matrix"
The carbon fiber bundle used is used in the form of a fiber or processed into a tape, prepreg, or chop.

  The thermoplastic resin of the matrix is supplied into the mold by extrusion molding or injection molding so as to melt and impregnate the carbon fiber bundle dispersedly arranged in the mold, and becomes a product through a pressure holding / cooling process. As a method of impregnating a carbon fiber bundle with a thermoplastic resin, a method in which the resin is heated and melted and impregnated in a fiber reinforcing material (melting impregnation method), a fiber-reinforced resin is obtained by a fluidized bed method or a suspension method. Any method can be used, such as a method of applying and fusing to a fiber (powder method), a method of dissolving a resin and removing the solvent after impregnating the fiber reinforcement (solution impregnation method), but using a melt impregnation method Is preferred. Further, when the carbon fiber bundle is impregnated with the thermoplastic resin, the carbon fiber web may be laminated.

"Use"
Applications of the carbon fiber reinforced composite material of the present invention include “OA devices such as personal computers, mobile phones, and personal digital assistants”, “refrigerators, air conditioners, and other home appliances”, “civils such as support columns, panels, and reinforcing materials, and building materials. Parts ”,“ automobile parts such as body skins, frames, wheels, and gear boxes ”and“ aircraft parts such as wings, main bodies, and landing gears ”.

  Hereinafter, the present invention will be described with reference to specific examples. However, the following examples do not limit the present invention.

[Press fluidity]
A carbon fiber bundle and a polypropylene resin film were cut out and laminated to 150 mm × 150 mm, and this laminate was press-molded at a temperature of 200 ° C. and a pressure of 20 MPa for 5 minutes to obtain a carbon fiber reinforced molding substrate. A carbon fiber reinforced molding substrate was cut into a thickness of 70 × 70 × 4 mm to obtain a fluidity evaluation sample. A fluidity evaluation sample was set in a flat plate mold of 100 × 100 × 2 mm, press-molded for 5 minutes at a temperature of 200 ° C., 20 MPa, and 10 MPa, and evaluated according to the following three stages depending on the filling condition. .
○: Filling is possible under any conditions of 20 MPa and 10 MPa.
Δ: Fillable at 20 MPa, unfilled portion can be confirmed at 10 MPa.
X: An unfilled part can be confirmed under any conditions of 20 MPa and 10 MPa.

[CF1-CF5 carbon fiber]
CF1: 1.4 dtex PAN-based carbon fiber, single fiber fineness: 1.4 dtex, single fiber diameter: 10 μm, single fiber roundness: 0.87, fiber length: 6.4 mm
CF2: 1.4 dtex PAN-based carbon fiber, single fiber fineness: 1.4 dtex, single fiber diameter 10 μm, single fiber roundness 0.87, fiber length 3.2 mm
CF3: 2.4 dtex PAN-based carbon fiber, single fiber fineness 2.4 dtex, single fiber diameter 13 μm, single fiber roundness 0.87, fiber length 6.4 mm
CF4: 2.4 dtex PAN-based carbon fiber, single fiber fineness 2.4 dtex, single fiber diameter 13 μm, single fiber roundness 0.87, fiber length 3.2 mm
CF5: 1.4 dtex PAN-based carbon fiber, single fiber fineness 1.4 dtex single fiber diameter 10 μm, single fiber roundness 0.75, fiber length 6.4 mm
CF6: 1.4 dtex PAN-based carbon fiber, single fiber fineness 1.4 dtex, single fiber diameter 10 μm, single fiber roundness 0.75, fiber length 3.2 mm
CF7: 0.7 dtex PAN-based carbon fiber, single fiber fineness 0.7 dtex, single fiber diameter 7 μm, single fiber roundness 0.90, fiber length 6.4 mm,
CF8: 0.7 dtex PAN-based carbon fiber, single fiber fineness 0.7 dtex, single fiber diameter 7 μm, single fiber roundness 0.90, fiber length 3.2 mm

[Thermoplastic resin]
-Polypropylene resin: manufactured by Nippon Polypro Co., Ltd., trade name: "NOVATEC" PP (registered trademark) SA06A

[Example 1]
The carbon fiber bundle (a) was cut to a length of 6.4 mm to obtain CF1. Moreover, the carbon fiber bundle was cut into 3.2 mm as the carbon fiber bundle (b) to obtain a carbon fiber bundle CF2. A substrate having a basis weight of 60 g / m 2 was obtained using this carbon fiber bundle. The papermaking method was used for dispersion.

  The obtained papermaking substrate was dried at a temperature of 100 ° C. for 1 hour. A 150 mm × 150 mm papermaking substrate and a PP film were laminated, put into a 200 ° C. press hot platen, and press molded at 20 MPa for 10 minutes to obtain a carbon fiber reinforced thermoplastic resin. The execution conditions and the evaluation results of the obtained carbon fiber reinforced thermoplastic resin are shown in Table 1.

[Example 2]
A substrate was obtained in the same manner as in Example 1 except that the mass ratio of the carbon fiber bundle (a) was 30% and the mass ratio of the carbon fiber bundle (b) was 70%. The execution conditions and the evaluation results of the obtained fiber reinforced thermoplastic resin are shown in Table 1.

[Example 3]
A substrate was obtained in the same manner as in Example 1 except that the mass ratio of the carbon fiber bundle (a) was 80% and the mass ratio of the carbon fiber bundle (b) was 20%. The execution conditions and the evaluation results of the obtained carbon fiber reinforced thermoplastic resin are shown in Table 1.

[Example 4]
The base was the same as in Example 1 except that CF3 carbon fiber was used and the mass ratio of carbon fiber bundle (a) was 50%, and CF4 carbon fiber was used and the mass ratio of carbon fiber bundle (b) was 50%. The material was obtained. The execution conditions and the evaluation results of the obtained carbon fiber reinforced thermoplastic resin are shown in Table 1.

[Example 5]
The same method as in Example 1 except that CF5 carbon fiber was used and the mass ratio of carbon fiber bundle (a) was 50%, and CF6 carbon fiber was used and the mass ratio of carbon fiber bundle (b) was 50%. A substrate was obtained. The execution conditions and the evaluation results of the obtained carbon fiber reinforced thermoplastic resin are shown in Table 1.

[Comparative Example 1]
A reinforcing fiber bundle was produced only with a CF1 carbon fiber bundle (a) having a length of 6.4 mm. Otherwise, a substrate was obtained in the same manner as in Example 1. The execution conditions and the evaluation results of the obtained fiber reinforced thermoplastic resin are shown in Table 1.

[Comparative Example 2]
The same method as in Example 1 except that CF7 carbon fiber was used and the mass ratio of carbon fiber bundle (a) was 50%, and CF8 carbon fiber was used and the mass ratio of carbon fiber bundle (b) was 50%. A substrate was obtained. The execution conditions and the evaluation results of the obtained carbon fiber reinforced thermoplastic resin are shown in Table 1.

[Comparative Example 3]
The same method as in Example 1 except that CF7 carbon fiber was used and the mass ratio of carbon fiber bundle (a) was 70%, and CF8 carbon fiber was used and the mass ratio of carbon fiber bundle (b) was 30%. A substrate was obtained. The execution conditions and the evaluation results of the obtained carbon fiber reinforced thermoplastic resin are shown in Table 1.

   As is apparent from Table 1, when carbon fibers having a single fiber fineness of 1.0 dtex to 2.4 dtex and a roundness of 0.70 or more and 0.90 or less are used, fluidity is improved, and as a result, press molding or the like is performed. It is easy to process, and a carbon fiber composite material that maintains the same properties in the secondary processing can be obtained.

Claims (10)

  A resin reinforcing material made of carbon fiber having a single fiber degree of 1.0 dtex to 2.4 dtex.   The resin reinforcing material according to claim 1, wherein the roundness of the single fiber of the carbon fiber is 0.70 or more and 0.90 or less.   The resin reinforcing material according to claim 1, wherein the resin reinforcing material contains carbon fiber in a range of 10 to 90% by mass.   The resin reinforcing material according to claim 1, wherein the carbon fiber has a length of 1 to 60 mm.   The resin reinforcing material according to claim 1, wherein the resin to be reinforced is a thermosetting resin or a thermoplastic resin.   The resin reinforcing material according to claim 1, wherein the resin reinforcing material has a porosity of 49 to 98% by volume.   The resin reinforcing material according to claim 1, wherein the resin reinforcing material is a mat material.   The resin reinforcing material according to claim 1, wherein the resin reinforcing material is a nonwoven fabric.   The resin reinforcing material according to claim 1, wherein the resin reinforcing material is a chop material.   The manufacturing method of the resin reinforcing material which manufactures the resin reinforcing material in any one of Claims 1-10 with any 1 type | molding method of press molding, RTM molding, and a hand lay-up method.