JPS6236460A - Thermosetting resin composition for composite material - Google Patents

Abstract

PURPOSE:To provide the titled compsn. which gives a composite material having a high mechanical strength at a high temp. and excellent toughness and heat resistance, consisting of a polyfunctional cyanate ester having a specified composition, a bismaleimide and a polysulfone. CONSTITUTION:A polyfunctionl cyanate ester (A) of formula I (wherein R is a residue of an arom. hydrocarbon formed by removing OH groups from a polyfunctional phenol compd.; n is at least 2), a bismaleimide (B) derived from maleic anhydride and an arom. diamine (e.g. m-phenylenediamine) and a polysulfone (C) of formula II (wherein n s 10-150) are blended in a weight ratio of A/B of 100/0-40/60 and C/(A+B+C) of 5/100-50/100.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field] The present invention relates to a thermosetting resin composition for composite materials having excellent heat resistance and toughness.

[Prior Art] Composite materials made of thermosetting resins and reinforcing materials such as carbon fibers, glass fibers, and aromatic polyamide fibers are widely used in premium sports applications such as golf shafts and fishing rods, and structural material applications such as aircraft. has been done. Conventionally, most of the thermosetting resins used in such composite materials are epoxy resins. However, in recent years, as composite materials have been desired to be used in applications that require even greater strength and toughness, thermosetting materials with excellent mechanical properties, especially toughness, and excellent heat and water resistance have been developed. The appearance of resin is strongly desired.

Thermosetting resins with better heat resistance than epoxy resins include resins whose main component is a bismaleimide compound (for example, Japanese Patent Publication No. 46-23250), resins whose main component is a polyfunctional cyanate ester (for example, Kosho 54-3044
Publication No. 0) and the like are known. However, these resins are generally more brittle than epoxy resins and are unsatisfactory for producing composite materials with excellent toughness.By blending thermoplastic resins with these resins before curing and curing, tensile elongation can be improved. Technology that improves Izotsu impact strength (
For example, JP-A-54-142297) has been proposed. Further, JP-A-57-165451 discloses a heat-resistant resin composition comprising a cyanate ester resin, a polyfunctional maleimide, and a polyether sulfon.

The compositions made of thermosetting resins mainly composed of cyanate esters as exemplified above are unsatisfactory as resins for composite materials that have both the heat resistance and toughness targeted by the present invention. The structure and effects of the present invention are clearly different.

[Objective of the present invention] The purpose of the present invention is to provide a thermosetting resin composition for composite materials that has excellent toughness and heat resistance, and more specifically, it is an object of the present invention to provide a thermosetting resin composition for composite materials that has excellent toughness and heat resistance. The object of the present invention is to provide a resin composition that enables the production of a composite material that has a low amount of carbon dioxide and has high mechanical strength at high temperatures.

[Structure of the present invention] The present invention is characterized in that it contains the following [A], [B] and [C], [A]/[B] has a weight ratio of 10010 to 40/60, [
C] / [[A] + [B] + [C)] is 5/1
A curable resin composition for composite materials having a polymer ratio of 00 to 50/100.

[A] Polyfunctional cyanate ester [B] Bismaleimide [C] Polysulfone” It is related to.

The polyfunctional cyanate ester used in the present invention has the formula R
(0-C3N). In the formula, R is an aromatic m group, and n is 2 or more. The organic group R is an aromatic hydrocarbon residue obtained by removing the OH group from a polyfunctional phenol compound, and an example of such a polyfunctional phenol compound is 2,2-bis(4-hydroxyphenyl)propane: 1 , 4-bis(4-hydroxyphenylpropyl)benzene; diphenol: 2,2-bis(
4-hydroxyphenyl)methane. A suitable example thereof is 2,2-bis(4-hydroxyphenyl)propane. Polyfunctional cyanate esters can be used as they are in the form of monomers, but when this monomer is polymerized in the presence or absence of a catalyst, the molecular size of Prepolymers can also often be used with preference.

The bismaleimide used in the present invention has two maleimide groups derived from maleic anhydride and an aromatic diamine.
It is an organic compound that has aromatic diamines such as metaphenylene diamine, xylylene diamine, bis(4-
aminophenyl)methane, bis(4-aminophenyl)
Bismaleimide using sulfone and 2,2-bis(4-aminophenyl)propane is preferably used. The bismaleimide used in the present invention may optionally contain the diamines exemplified for its production,
It can also be used in the form of a prepolymer obtained by reacting bismaleimide with a diamine.

In the thermosetting resin composition of the present invention, the ratio of polyfunctional cyanate ester to bismaleimide is 10010 to
It is necessary that the weight ratio is in the range of 40/60, preferably 9515 to 50150. That is,
When bismaleimide is added to a polyfunctional cyanate ester, the reactivity increases and the TO (glass transition temperature) increases, resulting in a tough resin. However, as shown in the examples below, if the content of bismaleimide exceeds the above ratio, not only will it not be possible to obtain a composite material with excellent toughness, but the tackiness and drape properties of the prepreg will be impaired, so this is not preferable as a resin composition for composite materials. do not have.

The polysulfone used in the present invention is represented by the following general formula, (in the formula, n is 10 to 150).
” is generally available.

The proportion of polysulfone used in the present invention is 5 to 50 parts by weight based on 1100 parts by weight of the total of polyfunctional cyanate ester, bismaleimide and polysulfone. In order to obtain a resin for composite materials that has both toughness and heat resistance as the object of the present invention, and also has excellent prepreg tackiness and drapability, polysulfone is preferably used in an amount of 10 to 30 parts by weight. If the amount is less than 5 parts by weight, the improvement in toughness will be extremely small, while if it is more than 50 parts by weight, the viscosity of the composition will be extremely high and impregnation into reinforcing fibers for composite materials will be poor.

It is possible to incorporate into the composition of the present invention an epoxy compound that is liquid at room temperature within a range that does not impair the original properties of the composition, thereby reducing the viscosity of the composition of the present invention and improving its impregnating properties into reinforcing fibers. It is advantageously used to improve the tackiness of prepreg. Further, although the composition of the present invention itself is cured by heating to give a heat-resistant cured product, a small amount of a catalyst can be included in order to accelerate the curing reaction. Such catalysts include Shimen metal salts such as zinc octylate and tin oleate, inorganic metal salts such as zinc chloride, and peroxides such as benzoyl peroxide and di-tert-butyl peroxide.

The present invention provides a thermosetting resin composition that provides a composite material with excellent toughness and heat resistance by combining a polyfunctional cyanate ester, bismaleimide, and polysulfone. By selecting the ratio of polyfunctional cyanate ester and bismaleimide, it is possible to obtain 1 q of thermosetting resin having heat resistance according to the use and purpose, and further, by combining polysulfone, toughness can be increased.

[Example] The present invention will be explained in further detail by the following example. In the examples below, the amounts of each ingredient represent the weight.

Example 1 2.65 parts of 2-bis(4-cyanatophenyl)propane and 7 parts of bis(4-maleimidophenyl)methane were mixed into 16
Prepolymerization was carried out for 2 hours at 0'C. After cooling, 8 parts of bisphenol A diglycidyl ether, polysulfone (UDE
L Pl 700) 20 parts, zinc octylate 0.02
1 part, 0.2 part of dicumyl peroxide and 300 parts of methylene chloride were added and uniformly dissolved. Add this solution to Toshiki Co., Ltd.)
A plain weave cloth made from Ta2O manufactured by "1~Reka" was coated and impregnated with resin gold (41%). After air drying for one day, the solvent was removed by heating in an oven at 140'C for 5 minutes to obtain a prepreg. This prepreg is made pseudo isotropic 2
Four sheets were laminated and cured in an autoclave at 240°C for 2 hours at a pressure of 6 kcJ/r:XK to a thickness of 5.
A 5 mm composite material was obtained. Impact energy of 680 kCJ-cm/cm (sample thickness) was applied to this composite material using a weight with a tip radius of 16 mm. The area of damage caused by the impact was measured using Canon Holosonic's ultrasonic flaw detection imaging device M.
The result of measurement using Model 400B was as small as 7.1cnf, and the impact resistance was excellent. Further, a composite material (about 2 mm thick) of 10 laminated sheets was fabricated using the same prepreg by O1-crepe molding using the above method. A test piece with a length of 9 mm and a width of 12.7 mm was cut from this composite material, and its bending strength was measured at room temperature and 120°C.
It was +1/mm2 to 5kq/mm2.87.

Example 2 45 parts of 2.2-bis(4-cyanatophenyl)propane and 45 parts of bis(4-maleimidophenyl>methane) were mixed into 1
Prepolymerization was carried out at 60'C for 2 hours.

After cooling, 10 parts of bisphenol A diglycidyl ether, 40 parts of polysulfone (Pl 700) and 0.2 parts of dicumyl peroxide were added and dissolved in 560 parts of methylene chloride to prepare a uniform resin solution. A composite material was produced using this resin solution in the same manner as in Example 1, and the damage area and bending strength due to impact energy were evaluated, and the results were as follows.

Impact damage area: 9.7 cif bending strength (room temperature > 115 kg/mm) 2 bending strength (120°C
> 90kCJ/mm2 Comparative Example 1 The physical properties of the composite material were evaluated in the same manner as in Example 2 except that polysulfone was not used. The results were as follows: Impact damage area 14.8ci Bending strength (air temperature) 120kq/mm 2 Bending strength (120℃>
94kq/mm2 Ratio Example 2 Evaluation was made in the same manner as in Example 2, with 27 parts of 2,2-bis(4-cyanatophenyl)propane and 63 parts of bis(4-maleimidophenyl)methane. The damaged area after impact was 13.0 otf, which was large and brittle.

[Effect of the invention] (1) Damage to composite materials due to impact is reduced.

(2) A composite material with excellent heat resistance is provided.

(3) Prepreg and composite materials with stable quality can be produced.

(4) A prepreg with tackiness and drapability can be produced.

(5) Composite materials can be molded using an autoclave without requiring special equipment.

Claims (1)

[Scope of Claims] Contains the following [A], [B] and [C], [A]/[
B] has a weight ratio of 100/0 to 40/60, [C]/[[A
] + [B] + [C]] in a weight ratio of 5/100 to 50/100. [A] Polyfunctional cyanate ester [B] Bismaleimide [C] Polysulfone