JPS6135941B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention is a carbon fiber reinforced plastic laminate (CFRP laminate) using carbon fiber as a reinforcing material.
Regarding. Conventionally, fiber-reinforced plastics (FRP) have been well known as materials with excellent specific strength (strength/density) and specific modulus (elastic modulus/density), and in particular glass fiber-reinforced plastics (GFRP) and carbon fiber-reinforced plastics. (CFRP) is used in large quantities in structural materials for artificial satellites, aircraft, and automobiles, as well as leisure equipment such as tennis rackets and golf shafts. However, while CFRP has superior mechanical properties such as tensile, bending, and compressive properties compared to GFRP, it has poor interlaminar shear strength, especially the ratio of interlaminar shear strength/tensile strength, which is extremely low compared to GFRP. It was hot. In addition, carbon fiber used as a reinforcing material has poor adhesion (wettability) with resin, and various surface treatment methods are being researched to improve this drawback. A surface treatment agent that has good adhesion with resin, such as a CFRP agent, has not yet been developed, and it is not possible to improve the interlaminar shear strength of a CFRP laminate. CFRP lamination is made by laminating multiple sheets of woven fabric made of carbon fibers, and using one piece of multilayer woven fabric made by weaving the carbon fibers so as to penetrate through the woven fabric, impregnating this with a thermosetting resin and hardening it. When used as a body, the interlaminar shear strength is improved, but when a plurality of these multilayer woven fabrics are used, the interlaminar shear strength is not improved. In addition, multilayer woven fabric is impregnated with resin,
It is not easy to mold and harden the material uniformly into a curved shape, resulting in variations in properties. The present invention solves these drawbacks. The present invention uses a plurality of multilayer woven fabrics made by laminating a plurality of woven fabrics made of carbon fibers, weaving the carbon fibers so as to penetrate through the woven fabrics, and using a plurality of integrated multilayer woven fabrics.
The present invention relates to a carbon fiber-reinforced plastic laminate obtained by providing a short fiber layer in all or part of the interlayers of the multilayer woven fabric, and impregnating and curing a thermosetting resin. The number of laminated layers of the multilayer woven fabric that is made by laminating a plurality of woven fabrics made of carbon fiber used in the present invention, and woven with carbon fibers so as to penetrate through the woven fabric,
There is no limit to the number of carbon fibers to be penetrated. The short fibers used in the present invention include carbon fibers,
It is obtained by cutting organic fibers such as glass fibers and aromatic polyamide fibers, and there are no restrictions on the length of the short fibers or the amount used. The type and amount of the binding agent and surface treatment agent for carbon fiber, glass fiber, aromatic polyamide fiber, etc.
There is no particular restriction as long as it is compatible with the thermosetting resin used. There are no restrictions on the method of impregnating and curing the thermosetting resin. As thermosetting resins, epoxy resins,
Vinyl ester resins, unsaturated polyester resins, etc. are used, and if necessary, appropriate curing agents or thickeners such as metal oxides are used, but there are no particular restrictions. Here, the resin content in the CFRP laminate is 35 to 35%.
50% by volume is desirable; if it is less than this, resin wilt and voids tend to remain in the molded product, and
Exceeding this is not desirable because the reinforcing effect of the carbon fibers decreases and the mechanical properties of the molded product are significantly reduced. The present invention will be explained below with reference to Examples. Parts are by weight. Example 1 100 parts of epoxy resin (manufactured by Ciba Geigy, trade name GY260) and 3 parts of curing agent (manufactured by Hashimoto Kasei, trade name
BF3/400) was mixed uniformly, and a polypropylene film (Toray No. 40 Type 2505 manufactured by Toray Industries, Inc.)
It was coated on the surface using a roll coater at 500 g/m ² . Three sheets of carbon fiber woven fabric (Torayka 6342 manufactured by Toray Industries, Inc.) are layered on top of this, and a roving made of long carbon fibers (Torayka 6342 manufactured by Toray Industries, Inc.) is layered on top of this.
T200A) was sewn through and a multilayer woven fabric was placed on top. For trading card T200A, 100g/m ² was used. On top of this, short fibers of trading card T200A cut into 2-inch lengths are uniformly sprinkled at a rate of 100 g/m ² to form a layer of short fibers, and on top of that, another layer of the above-mentioned Polypropylene films coated with epoxy resin were overlapped, rolled up to cover both, and aged at 80°C for 48 hours to impregnate the epoxy resin composition and bring it into a semi-cured state, yielding a prepreg material. Next, the prepreg material is cut to a certain length, the polypropylene film is peeled off from both sides, and three of these are stacked to form a flat plate of 3 mm in total.
After heating and pressure molding to 110°C using a spacer, the temperature was subsequently raised to 150°C and cured for 1 hour. After cooling to 100℃, remove and further heat to 160℃.
It was cured at ℃ for 4 hours to obtain a 3 mm thick CFRP laminate. Comparative Example 1 500 g of the epoxy resin composition used in Example 1 was placed on the polypropylene film used in Example 1.
m ² using a roll coater, the carbon fiber multilayer woven fabric used in Example 1 is laminated on top of this, and another sheet of the above-mentioned epoxy resin composition is coated on top of this. Example 1
A prepreg material was prepared under the conditions described. Next, the prepreg material was cut into a certain length, the polypropylene film was peeled off from both sides, and three sheets were stacked together under the same conditions as in Example 1 to form a 2.8 mm CFRP laminate. Example 2 500 g/m ² of the epoxy resin composition used in Example 1 was applied onto the polypropylene film described in Example 1.
The carbon fiber multilayer woven fabric described in Example 1 was laminated on top of this using a roll coater, and then a 1-inch glass roving (manufactured by Fuji Fiberglass Co., Ltd., FER0730) was applied on top of this. Short fibers cut into lengths are uniformly spread at a rate of 100g/ ^m2 to form a layer of short fibers, and on top of that, another polypropylene film coated with the aforementioned epoxy resin is layered. Both sides were covered and rolled up to obtain a prepreg material under the conditions described in Example 1. Next, the prepreg material was cut to a certain length, the polypropylene film was peeled off from both sides, three sheets were stacked together, and cured under the same conditions as in Example 1 to form short glass fibers with a thickness of 3 mm.
It was made into a CFRP laminate. Example 3 500 g/m ² of the epoxy resin composition used in Example 1 was applied onto the polypropylene film described in Example 1.
The carbon fiber multi-layer woven fabric used in Example 1 was laminated on top of this using a roll coater, and then Kevlar fiber (KEVLAR) was applied on top of this.
Trademark issued by Dupont, Kevlar 49 manufactured by Dupont,
760 denier yarn) cut into 1-inch lengths are uniformly scattered at a rate of 100 g/m ² to form a layer of short fibers, and on top of that, another layer of the above-mentioned epoxy resin composition is applied. Polypropylene films coated with the material were overlapped and rolled up to cover both surfaces, and a prepreg material was obtained under the conditions described in Example 1. Next, cut the prepreg material to a certain length,
The polypropylene film was peeled off from both sides, three sheets were stacked together, and cured under the same conditions as in Example 1 to obtain a CFRP laminate containing Kepler short fibers having a thickness of 3 mm. Ten test pieces each with a width of 10 mm and a length of 60 mm were cut from the CFRP laminates prepared in Examples 1 to 3 and Comparative Example 1, and the interlaminar shear strength was measured by the short beam method with a span of 12 mm and a test speed of 1.5 mm/min. did. The results are shown in Table 1 as average values.

[Table] In Examples 1 to 3, the prepreg material was cured, but after forming a layer of short fibers between the layers of the multilayer woven fabric, it was impregnated with a thermosetting resin heated to lower the viscosity, and then cured. A CFRP laminate may also be used, and the molding method is not limited to the prepreg method. In addition, when the cross sections of Examples 1 to 3 were observed under a microscope, it was found that short fibers had penetrated into the multilayer woven fabric. As shown in Table 1, the CFRP laminate of the present invention has a short fiber layer formed between all or part of the interlayers of a multilayer woven fabric, and the short fibers are embedded into the multilayer woven fabric by pressure molding, mold molding, etc. , it is possible to improve interlaminar shear strength, which is the biggest drawback of carbon fiber. With a single sheet of multilayer woven fabric, an interlayer shear strength of approximately 5.7 Kgf/mm ² was obtained, but it is actually difficult to change the thickness of multilayer woven fabric according to various molded products, and multilayer woven fabric When molding a molded product with a curved surface when the thickness exceeds 2 to 3 mm, the difference between the outer periphery and the inner periphery causes wrinkles in the multilayer woven fabric, resulting in variations in resin content. High-strength CFRP laminates can be manufactured without worry.

Claims (1)

[Claims] 1. Laminated multiple sheets of woven fabric made of carbon fiber,
A plurality of multilayer woven fabrics are woven with carbon fiber so as to penetrate through this woven fabric, and a short fiber layer is provided between all or part of the multilayer woven fabrics, and a thermosetting resin is impregnated and hardened. Carbon fiber reinforced plastic laminate. 2. The carbon fiber reinforced plastic laminate according to claim 1, wherein the short fibers are carbon fibers. 3. The carbon fiber reinforced plastic laminate according to claim 1, wherein the short fibers are glass fibers. 4. The carbon fiber reinforced plastic laminate according to claim 1, wherein the short fibers are organic fibers such as aromatic polyamide fibers.