JPS63161027A - Carbon fiber composite material - Google Patents

Abstract

PURPOSE:To obtain the titled composite material having quick curability and excellent heat-resistance and mechanical characteristics, by using a polycarbodiimide resin containing plural carbodiimide groups in one molecule and a prepolymer of said resin as matrix resin of the material. CONSTITUTION:The objective composite material can be produced by using one or more components selected from a polycarbodiimide resin containing >=2 carbodiimide groups in one molecule and a prepolymer of said resin as a matrix resin of the composite material.

Description

Detailed Description of the Invention [Field of Industrial Application] The present invention relates to a carbon fiber composite material containing a polycarbodiimide-based thermosetting resin, and more specifically, a polycarbodiimide having two or more carbodiimide groups in the molecule as an essential component. The present invention relates to carbon fiber composite materials containing resin.

[Conventional technology]

In recent years, carbon fiber composite materials have been used for various structural members due to their excellent strength, high elastic modulus, and light weight.

Typical examples include aircraft parts, golf clubs, and tennis rackets. In more advanced applications, it is also applied to components of rockets and artificial satellites.

The manufacturing method generally involves creating a sheet-like intermediate using a thermosetting resin as a matrix, and then laminating the intermediates and thermosetting them to obtain a molded product.

Epoxy resin is known as the most commonly used matrix resin for carbon fibers.

[Problem that the invention seeks to solve]

This epoxy resin has high adhesive strength and interlaminar shear strength of 7K.
g/an" or more, making it possible to obtain a high-performance composite material, but it has the drawback of requiring long curing conditions of 60 minutes or more at 120 to 170°C, and carbon fibers made using this epoxy resin Composite materials cannot be said to be fully satisfactory in terms of heat resistance, and in fields such as aerospace, which are exposed to severe high temperature conditions, the emergence of carbon fiber composite materials with even higher heat resistance is desired. .

Generally, the heat resistance of carbon fiber composite materials largely depends on the heat resistance of the resin that forms the matrix. This is a high temperature (250
This is because there is almost no effect at temperatures below 30°F (℃).

Therefore, in order to obtain a carbon fiber composite material that satisfies the above requirements, a matrix resin must be used that is faster curing than epoxy resin and has appropriate heat resistance.5 [Means for solving the problem] ] The present invention was made for the purpose of solving the problems of the prior art as described above, and providing a carbon fiber composite material using a matrix resin that is faster curing than epoxy resin and has higher heat resistance. Its composition consists of at least two
It is characterized by containing as a matrix resin at least one of a polycarbodiimide resin containing two or more carbodiimide groups and a prepolymer thereof.

That is, as a result of intensive research, the inventors of the present invention sought to find a combination of matrix resin and carbon fiber that cures quickly to carbon fiber, has adhesive strength comparable to that of epoxy resin, and has higher heat resistance. The present invention was completed by learning that a polycarbodiimide resin may be used as the matrix resin, and the carbon fiber composite material containing a thermosetting resin of the present invention can be manufactured by using an epoxy resin. It cures faster than other materials, has good heat resistance, and exhibits excellent mechanical properties.

Next, the present invention will be explained in detail.

The carbodiimide resin used in the present invention is made of one or more organic polyisocyanates and one or more organic monoisocyanates while controlling the molecular weight by using one or more catalysts that promote carbodiimidation of isocyanate. Most preferred are substantially aqueous polycarbodiimide resins.

It is known that the average molecular weight of polycarbodiimide can be controlled by a method of stopping polycondensation using this organic monoisocyanate (I, M. Alberino et al. JAPS
, 21, 1999-20081977), but no attempt has been made to create a carbon fiber composite material with improved heat resistance by combining it with carbon fiber or the like.

According to the present invention, first, a prepreg is produced by impregnating carbon fibers with a polycarbodiimide resin whose ends are capped with phenyl groups in a melted or solution form. This prepreg has thermosetting properties and can be hot-press molded. Therefore, a desired composite material can be obtained by molding it into a desired shape using hot pressure molding.

By firing the obtained composite material at about 1000° C. in an inert gas, a c/c composite can be obtained with a high yield. Furthermore, by impregnating a c/c composite with a varnish-like carbodiimide resin and firing it, a c/c composite with high yield, high efficiency, and high density can be obtained.

〔Example〕

Examples of the present invention are shown below.

Example 1 250 g of methylene diphenyl diisocyanate.

A composition of 23 g of phenyl isocyanate was carbodiimidated in tetrachloroethylene at 120° C. by adding 3-methyl-1-phenylphosphorene-1-oxide as a catalyst to obtain a powdery resin. 1 of the powdered resin
It was melted at 20-140°C, impregnated into carbon fibers, and wound onto a drum. By sandwiching the impregnated carbon fiber between two rollers and controlling the gap between them, the resin content can be reduced to 4.
The content was adjusted to 0% by weight to obtain a prepreg. The obtained prepregs were laminated in one direction and pressed at 200° C. for 10 minutes to obtain a molded product.

The physical properties of this molded product were as follows.

Density: 1.38 Bending strength: 40 kg/mm2 Heat distortion temperature: 210°C Example 2 Prepreg was produced in the same manner as in Example 1, the resulting prepregs were laminated in one direction, and pressed at 350°C for 10 minutes to form a molded product. I got it.

The physical properties of this molded product were as follows.

Density 1.38 Bending strength 35 kg/nwn2 Heat deformation temperature 300°C or higher Example 3 A resin was synthesized in the same manner as in Example 1, and the resin was
Melt it at 0℃ and impregnate it into a cloth made of carbon fiber,
Prepreg was produced.

This prepreg was laminated and pressed at 350°C to obtain a molded product.

The physical properties of this molded product were as follows.

Density: 1.35 Bending strength: 20 kg/nwy+'' Heat deformation temperature: 300°C or higher Example 4 A molded product was obtained in the same manner as in Example 3, and then the molded product was fired at 1000°C for 1 hour under vacuum.

The physical properties of this product were as follows.

Bulk density 1.20 Bending strength 9 kg/+nm" Example 5 The c/c composite obtained in Example 4 was impregnated with a tetrachloroethylene solution of carbodiimide resin, dried, and then fired at 1000° C. for 1 hour under vacuum.

The physical properties of this product were as follows.

Bulk density 1.40 Bending strength 18 kg/mm2 Example 6 A composition of 200 g of tolylene diisocyanate and 5 g of phenyl isocyanate was heated at 120°C in tetrachloroethylene.
3-methyl 1-phenol-2-phosphosine-1-
Oxide was added as a catalyst to carry out carbodiimidation to obtain a resin varnish.

A cross made of carbon fiber is impregnated with this varnish.7
It was dried at 0°C to obtain a prepreg.

The physical properties of the molded product were as follows.

Density Degree 1.35 Bending strength 20kg/nu2 Heat deformation temperature 300℃ or more

Claims (1)

[Claims] A carbon fiber composite material comprising, as a matrix resin, at least one of a polycarbodiimide resin containing at least two or more carbodiimide groups in its molecule and a prepolymer thereof.