JPH0747616B2 - Imide oligomer-composition - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an imide oligomer composition.
More specifically, the present invention is an imide oligomer composition comprising a specific imide oligomer (A), imide oligomer (B) or polynadiimide (C), and alkenylphenol, which is heat-cured to improve heat resistance and moldability. The present invention relates to an imide oligomer composition which produces a polyimide resin excellent in both.

[Conventional technology]

BACKGROUND ART Conventionally, there is known a composite material constituted by using a resin such as an epoxy resin or a polyimide resin as a matrix and a fiber such as a glass fiber, an aramid fiber, a carbon fiber or a silicon carbide fiber as a reinforcing material, a so-called fiber-reinforced composite material. .

Molding of the fiber-reinforced composite material, first, to prepare a resin film on the release paper, impregnate the fibers, the so-called hot melt method, or varnish prepared by dissolving the resin in a solvent, impregnate the fibers in advance, The prepreg is prepared by making this into a size dry state, removing the solvent, and sandwiching it in a release paper. The prepregs are laminated with an arbitrary number or at a laminating angle, placed in an autoclave, and the resin is cured at a constant temperature and pressure to obtain a fiber-reinforced composite material molded product.

[Problems to be Solved by the Invention]

When a polyimide resin is used, the resulting fiber-reinforced composite material has good heat resistance, but requires molding at high temperature and high pressure, and further has drawbacks such as easy formation of voids.

Therefore, the present inventors aimed at a polyimide resin excellent in heat resistance and moldability, and regarding an imide oligomer which is a precursor thereof, an aromatic tetracarboxylic acid or a derivative thereof, a condensate of o-ethylaniline and formaldehyde. , And an imide oligomer obtained by reacting three components of a terminal functionalizing agent, and previously filed a patent application (JP-A-59-
167569).

However, when molding a fiber-reinforced composite material molded product using the imide oligomer of the above invention, for example, when prepregs are cross-oriented and laminated, curing shrinkage of the resin or thermal expansion of the resin and the fiber. It was found that thermal cracking due to the difference in the coefficient causes molding cracks in the obtained molded product.

On the other hand, the following formula (I) (In the formula, D represents a divalent group containing a carbon-carbon double bond.) A polyimide containing at least two groups in one molecule, an alkenylphenol and / or an alkenylphenol ether, A method for producing a crosslinked polymer containing an imide group by reacting it in the presence of a polymerization catalyst in some cases (JP-A-52-994)
It has been known.

However, in the method for producing a crosslinked polymer containing this imide group, molding cracks during molding are improved,
It has a drawback that the heat resistance of the cured product is lowered.

An object of the present invention is to provide an imide oligomer composition in which molding cracking is improved without lowering heat resistance after heat curing.

Another object of the present invention is to provide an imide oligomer composition which can be cured at a relatively low temperature and has good moldability.

[Means for Solving the Problems]

That is, the gist of the present invention is an imide oligomer composition comprising the following imide oligomer (A), imide oligomer (B) or polynadiimide (C), and alkenylphenol.

(A) Aromatic tetracarboxylic acid or its derivative, o-
A condensate of ethylaniline and formaldehyde, and
Imide oligomer (A) obtained by reacting three components of maleic acid or its derivative (b) aromatic tetracarboxylic acid or its derivative, o-
A condensate of ethylaniline and formaldehyde, and
Imide oligomer (B) obtained by reacting three components of nadic acid or its derivative (c) Polynadiimide (C) obtained by reacting a condensate of o-ethylaniline and formaldehyde with nadic acid or its derivative In the present invention, as the aromatic tetracarboxylic acid constituting the imide oligomer, pyromellitic acid, 3,3 ', 4,
4'-benzophenone tetracarboxylic acid, 3,3 ', 4,4'-
Diphenyl ether tetracarboxylic acid, 3,3 ', 4,4'-
Biphenyltetracarboxylic acid, 2,3,6,7-naphthalenetetracarboxylic acid, 2,3,4,5-thiophenetetracarboxylic acid, 3,4,9,10-perylenetetracarboxylic acid, 2,2-bis ( Mention may be made of 3,4-dicarboxyphenyl) propane and the like, and isomers thereof, and these may be used in a plurality. These tetracarboxylic acid components can also be used in the form of derivatives such as lower alkyl ester and dianhydride.

Further, as a method for producing a condensate of o-ethylaniline and formaldehyde, which constitutes an imide oligomer and a polynadiimide, a method of reacting in an aqueous medium in the presence of a strong inorganic acid such as hydrochloric acid or sulfuric acid at 60 to 100 ° C. Kaisho 47-319
No. 61) and the like.

In the method, the diamine 3,3'-diethyl-
In addition to 4,4'-diaminodiphenylmethane, triamine,
Tetraamine and the like are by-produced, but in the present invention, these by-products can be used for producing an imide oligomer without separation. It is also possible to add aniline during the condensation reaction of o-ethylaniline and formaldehyde. At this time, instead of aniline, o-toluidine, o
It is also possible to use a condensate of o-ethylaniline in which an aniline derivative having no substituent at the p-position such as -chloroaniline is added.

The terminal functionalizing agent used for the imide oligomer (A) is maleic acid or a derivative thereof, and the terminal functionalizing agent used for the imide oligomer (B) and the polynadiimide (C) is nadic acid (5-norbornene-2, 3-dicarboxylic acid) or a derivative thereof.

The imide oligomers (A) and (B) are prepared by heating the above aromatic tetracarboxylic acid or its derivative, a condensate of o-ethylaniline and formaldehyde, and three components of a terminal functionalizing agent in the following solvent, or If necessary, it can be produced by reacting in the presence of an imidization catalyst and a dehydrating agent. The polynadiimide (C) is prepared by reacting a condensate of o-ethylaniline and formaldehyde with a terminal functionalizing agent in the following solvent with heating or, if necessary, in the presence of an imidization catalyst and a dehydrating agent. It can be manufactured.

Examples of the solvent used in the reaction include amide solvents such as N, N-dimethylformaldehyde, N, N-dimethylacetamide and N-methyl-2-pyrrolidone, phenols such as m-cresol and dimethyl sulfoxide. Can be mentioned.

The proportions of the three components of the aromatic tetracarboxylic acid, the condensate of o-ethylaniline and formaldehyde, and the terminal functionalizing agent are appropriately determined depending on the purpose and in relation to the physical properties. For example, when the condensate of o-ethylaniline and formaldehyde is a diamine, the molar ratio of each component (aromatic tetracarboxylic acid / condensate of o-ethylaniline and formaldehyde / terminal functionalizing agent) is generally Is n / (n +
Although it can be expressed as 1) / 2, the proportion of the terminal functionalizing agent may be purified and removed after the reaction when an excessive amount is used for surely introducing the terminal functional group. However, since the molecular weight of the imide oligomer formed is determined by the value of n, it is preferable to strictly adjust the molar ratio of tetracarboxylic acid and diamine. Usually, the value of n can be in the range of 1 to 15. Since the molecular weight of the oligomer formed increases as the value of n increases, and the viscosity of the solution increases, making it difficult to produce prepreg. Therefore, the value of n is preferably 1 to 10, and the molecular weight of the oligomer is
6000 or less can be mentioned.

In the imide oligomer composition of the present invention, the equivalent ratio of the imide oligomer (A) to the imide oligomer (B) or the polynadiimide (C) may be in the range of 40:60 to 90:10. If this equivalent ratio exceeds the above range, the heat resistance of the cured product will decrease, and conversely, if this ratio decreases, the reactivity will decrease, and a higher molding temperature is required, which is not preferable.

The alkenylphenols used in the present invention are mono-, di- or polyallylphenols, preferably dialkenylphenols.

Examples of typical dialkenylphenols include compounds represented by the following general formula (I).

(In the formula, R ₁ is —CH ₂ —, —C (CH ₃ ) ₂ —, —SO ₂ —,
-SO -, - S -, - O -, - CH (C 6 H 5) - or -C (CH
_{3) 2 - (C 6 H} 5) -C (CH 3) 2 - represents and n
Represents 0 or 1. ) Examples of alkenylphenols are 2-allylphenol, 2,2-bis (4-hydroxy-3-allylphenyl) propane [diallylbisphenol A], bis (4
-Hydroxy-3-allylphenyl) sulfone [diallylbisphenol S], 4,4'-dihydroxy-3,3'-
Examples include diallyldiphenyl, bis (4-hydroxy-3-allylphenyl) methane and the like, and methallyl compounds corresponding to these, and a plurality of these can be used.

The alkenylphenol used in the present invention can be produced by a known method by Claisen transition of alkenyl ether.

In the imide oligomer composition of the present invention, the amount of alkenylphenol used is the imide oligomer (A).
The range of 0.1-10, preferably 0.3-3.0 equivalent can be mentioned with respect to 1 equivalent. If it is less than this range, the effect of improving the molding cracking is small, and if it is more than this range, the heat resistance of the cured product decreases, which is not preferable.

The imide oligomer composition of the present invention may be composed of N, N-dimethylacetamide, which is a component of the imide oligomers (A) and (B), polynadiimide (C) and alkenylphenol, depending on the structure and the molecular weight of the oligomer. N, N-dimethylformamide, N-methyl-2
In addition to amide solvents such as pyrrolidone, it is soluble in ketones such as acetone and methyl ethyl ketone, ethers such as tetrahydrofuran, dioxane and dimethoxyethane, and halogen solvents such as methylene chloride and 1,2-dichloroethane.

The prepreg produced by the imide oligomer composition of the present invention can be usually produced by making a 20 to 80% by weight solution, impregnating this with a reinforcing fiber, and drying.

〔Example〕

Hereinafter, the imide oligomer composition of the present invention will be specifically described by way of examples, but the present invention is not limited to these examples.

The molding cracking evaluation of molded product, the [90 _{2/0 2/90]} s10 layer cross oriented laminated material after curing in an autoclave, subjected to post curing in an oven, and observing the cross section of the molded product by a microscope, The number of cracks in the central 90 ° layer is the number per unit length (pieces
/ cm).

The glass transition temperature (Tg) was calculated from the change in the thermal expansion curve by the TMA method. The results are shown in Table 1.

Reference Example 1 Synthesis of maleimide-terminated imide oligomer (1) In a four-necked flask, o-ethylaniline / formaldehyde condensate (manufactured by Nippon Kayaku Co., Ltd., trade name Kayahard AA)
3,3'-diethyl-4,4'-diaminodiphenylmethane (3,3'-EDDM) (53.3 g, 0.21 mol) was obtained by distillation under reduced pressure.
After uniformly dissolving in 63.8 g of N, N-dimethylformamide (DMF), 33.7 g (0.105 mol) of 3,3 ′, 4,4′-benzophenonetetracarboxylic dianhydride (BTDA) was dispersed in 191.99 g of DMF. , Added to the above diamine solution. After stirring at room temperature for 1 hour, 22.6 g (0.23 mol) of maleic anhydride (MA) was added and stirred at room temperature for 1 hour to produce an amic acid oligomer. Then, 85.5 g of acetic anhydride as a dehydrating agent and 4.3 g of sodium acetate as an imidizing catalyst were added and the temperature was raised to carry out an imidizing reaction at 70 ° C. for 1 hour.

After completion of the reaction, the mixture was cooled to room temperature, and the reaction solution was gradually added to a large amount of water to precipitate an imide oligomer. Then, the imide oligomer was separated, neutralized with 1% heavy sour water, washed with a large amount of water, and vacuum dried at 60 ° C. for 60 hours. The yield was almost quantitative, and a maleimide-terminated imide oligomer having a number average molecular weight of 955 was obtained.

Reference Example 2 Synthesis of Maleimide Terminal Oligomer (2) Using 3,3′-EDDM 152.7 g (0.60 mol), ETDA128.9 g (0.40 mol), MA43.2 g (0.44 mol), the same operation as in Reference Example 1 A maleimide-terminated imide oligomer having a number average molecular weight of 1,500 was obtained.

Reference Example 3 Synthesis of maleimide-terminated imide oligomer (3) 3,3′-EDDM 152.6 g (0.60 mol), pyromellitic anhydride (PMDA) 65.4 g (0.30 mol) instead of BTDA, MA64.7 g (0.
(66 mol) was used and a procedure similar to that of Reference Example 1 was carried out to obtain a maleimide-terminated imide oligomer having a number average molecular weight of 85.

Reference Example 4 Synthesis of Nadiimide Terminated Imide Oligomer (1) 3,3′-EDDM 46.8 g (0.18 mol), EDTA 29.6 g (0.09 mol), nadic acid (NA) 33.2 g (0.20 mol), N-methyl as a solvent Using 255.8 g of 2-pyrrolidone (NMP), an amic acid oligomer was produced in the same manner as in Reference Example 1. After standing overnight at room temperature, the imidization reaction was carried out at 200 ° C. for 2 hours.

After completion of the reaction, the mixture was cooled to room temperature, the homogeneous reaction liquid was poured into a 5% aqueous pyridine solution to precipitate an imide oligomer, dispersed in water 4 times, washed, and vacuum dried at 100 ° C. for 60 hours. The yield was quantitative and a nadimide-terminated imide oligomer with a number average molecular weight of 1100 was obtained.

Reference Example 5 Synthesis of Nadiimide Terminated Imide Oligomer (2) 3,3′-EDDM 46.8 g (0.18 mol), PMDA 20.1 in place of ETDA
Using g (0.09 mol) and NA33.2 g (0.20 mol), a nadiimide-terminated imide oligomer having a number average molecular weight of 1000 was obtained in the same manner as in Reference Example 4.

Reference Example 6 Synthesis of bisnadiimide (3) 3,3'-EDDM 25.4 g (0.10 mol), NA36.1 g (0.22 mol)
Was used in the same manner as in Reference Example 4 to obtain a bisnadiimide having a number average molecular weight of 550.

Example 1 52.8 g of maleimide-terminated imide oligomer of Reference Example 1 and 30.0 g of nadiimide-terminated imide oligomer of Reference Example 4 and diallylbisphenol A (BPA-C manufactured by Mitsui Toatsu Fine Co., Ltd.)
A) 17.1 g [MA / NA / allyl = 2/1/2 equivalent ratio] was dissolved in tetrahydrofuran (THF) 233.1 g to prepare a varnish. Carbon fiber trading card T-400 (manufactured by Toray) was impregnated with this to prepare a prepreg. This prepreg [90 _{2/0 2/90]} s
10 layers were laminated with the above constitution and cured in an autoclave under a pressure of 7 kg / cm ² at 230 ° C. for 4 hours to form a cross-oriented laminated material. Further, post-curing was performed in an oven at 250 ° C. for 1 hour, 270 ° C. for 1 hour, and 290 ° C. for 6 hours. Tg of cured product is 2
The temperature was 92 ° C, and voids and molding cracks were not observed.

Example 2 35.2 g of maleimide-terminated imide oligomer of Reference Example 1 and 20 g of nadiimide-terminated imide oligomer of Reference Example 4 and 12.2 g of diallyl bisphenol S (manufactured by Nippon Kayaku Co., Ltd.) [MA / NA / allyl = 2/1/2 equivalent ratio] ] Was dissolved in 157.2 g of THF to prepare a varnish. A prepreg was prepared and cured in the same manner as in Example 1. The Tg of the cured product was 320 ° C., and the molded product did not have voids or molding cracks.

Example 3 A varnish was prepared from 34.6 g of the maleimide-terminated imide oligomer of Reference Example 3, 20 g of the nadiimide-terminated imide oligomer of Reference Example 5, 12.6 g of diallylbisphenol A, and 156.8 g of THF. A prepreg was prepared and cured in the same manner as in Example 1. As a result, the cured product had a Tg of 316 ° C., but a very small amount of microcracks were observed.

Example 4 34.9 g of the maleimide-terminated imide oligomer of Reference Example 1, 20 g of bisnadiimide of Reference Example 6 and diallylbisphenol S
A varnish was prepared from 12.1 g and THF 133.0 g. A prepreg was prepared and cured in the same manner as in Example 1, and as a result, a cured product was obtained.
The Tg was 308 ° C., and there was no void or molding crack in the molded product.

Example 5 55.0 g of maleimide-terminated imide oligomer of Reference Example 2, 10 g of nadiimide-terminated imide oligomer of Reference Example 4, 5.0 g of bisnadiimide of Reference Example 6, and diallylbisphenol
A varnish was prepared from A12.1 g and THF191.6 g. A prepreg was prepared and cured in the same manner as in Example 1. As a result, the cured product had a Tg of 285 ° C., and the molded product did not have voids or molding cracks.

Comparative Example 1 50 g of the maleimide-terminated imide oligomer of Reference Example 1 was added to THF11.
It was dissolved in 7 g to prepare a varnish. In the same manner as in Example 1, the carbon fiber was impregnated with the varnish and the prepreg was laminated, and cured at 250 ° C. for 4 hours under a pressure of 7 kg / cm ² . As a result, molding cracks occurred in the molded product. Further, after-curing was carried out in an oven at 270 ° C. for 1 hour, 290 ° C. for 1 hour, and 320 ° C. for 6 hours. As a result, Tg was 300 ° C.

Comparative Example 2 47.8 g of the maleimide-terminated imide oligomer of Reference Example 1 and 54.4 g of the nadiimide-terminated imide oligomer of Reference Example 4 were mixed with THF.
It was dissolved in 238.5 g to prepare a varnish. In the same manner as in Example 1, the carbon fiber was impregnated with the varnish, and the prepreg was laminated to obtain 7 kg / cm ^2.
Curing was carried out under pressure at 250 ° C. for 4 hours. As a result, molding cracks occurred in the molded product. 1 at 270 ° C in the oven
As a result of post-curing at 290 ° C. for 1 hour and 320 ° C. for 6 hours, Tg was 320 ° C.

Comparative Example 3 82.9 g of maleimide-terminated imide oligomer of Reference Example 2 and 17.1 g of diallylbisphenol A [MA / allyl = 1/1 equivalent ratio]
Was dissolved in 233 g of THF to prepare a varnish. A prepreg was laminated in the same manner as in Example 1 and cured at 220 ° C. for 4 hours under a pressure of 7 kg / cm ² to obtain a molded product. Further, after curing at 230 ° C. for 1 hour, 250 ° C. for 1 hour, 270 ° C. for 1 hour, 290 ° C. for 1 hour, and 320 ° C. for 6 hours, there was no molding crack in this molded product, but Tg was 193. It was ℃.

EFFECTS OF THE INVENTION The present invention is excellent in that when two specific functionalizing agents and alkenylphenols are used, they are free from molding cracks when they are used as raw materials for fiber-reinforced cross-oriented laminated material moldings. It was found that an imide oligomer composition having excellent heat resistance can be obtained.

The imide oligomer composition of the present invention can be heat-cured to obtain a fiber-reinforced composite material having excellent heat resistance. Furthermore, molding cracks do not occur during heat curing.

When the imide oligomer composition of the present invention is dissolved in the above-mentioned solvent, the viscosity of the resulting solution is low, so that the reinforcing fiber is well impregnated and the prepreg is easily manufactured.

Further, the imide oligomer composition of the present invention is soluble in organic solvents, various additives, reinforcing materials such as dialiphthalate, triallyl isocyanurate, reactive diluents such as divinylbenzene, carbon powder, various metals, It is easy to mix metal oxides, silica, asbestos, etc., and can be used for producing not only fiber-reinforced composite materials but also adhesives, coating materials, molded products, etc. having good heat resistance.

Claims (1)

[Claims] 1. An imide oligomer composition comprising the following imide oligomer (A), imide oligomer (B) or polynadiimide (C), and alkenylphenol. (A) Aromatic tetracarboxylic acid or its derivative, o-
A condensate of ethylaniline and formaldehyde, and
Imide oligomer (A) obtained by reacting three components of maleic acid or its derivative (b) aromatic tetracarboxylic acid or its derivative, o-
A condensate of ethylaniline and formaldehyde, and
Imide oligomer (B) obtained by reacting three components of nadic acid or its derivative (c) Polynadiimide (C) obtained by reacting a condensate of o-ethylaniline and formaldehyde with nadic acid or its derivative