JPS63258926A - Imide oligomer composition - Google Patents

Abstract

PURPOSE:To obtain a solvent-soluble imide oligomer composition outstanding in storage stability and molding processability, capable of conversion into a highly heat-resistant polyimide by heating, by blending each specific imide oligomer and maleimide. CONSTITUTION:The objective composition can be obtained by blending (A) an imide oligomer prepared by reaction between A1: an aromatic tetracarboxylic acid or its derivative (pref. dianhydride), A2: a polyamine consisting mainly of condensate from O-ethylaniline and formaldehyde (pref. tri- or higher amine accounting for <=50wt.% of the polyamine) and A3: a nadic acid or its derivative (pref. nadic anhydride) and (B) a polymaleimide prepared by reaction at low temperatures in the presence of, pref., dehydrating agent and imidizing catalyst, between the polyamine A2 and maleic acid (derivative) in such a manner that the equivalent ratio of the end group of the component A to that of the component B is 60:40-10:90.

Description

Detailed Description of the Invention [Field of Industrial Application] The present invention relates to an organic solvent-soluble imide oligomer composition with excellent storage stability and moldability.
The present invention provides a precursor that can be self-cured by heat without producing volatile components such as alcohol, and can be converted into a polyimide resin with good heat resistance. In particular, the present invention relates to an imide oligomer composition suitable for producing a fiber-reinforced composite material with good heat resistance, which uses glass fiber, aramid fiber, carbon fiber, silicon carbide fiber, etc. as a reinforcing material.

[Conventional technology]

Pyromellitic dianhydride (PMDA) or 3,
It has already been known that polyimide resins with good heat resistance can be obtained by reacting aromatic diamines with J', 4C,≠'-benzophenonetetracarboxylic dianhydride (BTDA) or derivatives thereof such as acids and lower alkyl esters. Are known. Generally, these polyimides are insoluble and infusible and have extremely poor moldability, so to mold them, moldable precursors such as polyamic acids or polyamide esters are used, and after molding into films etc., they are imidized. will be held. At this imidization stage, volatile components such as water and alcohol are produced, so if this process is applied to a fiber reinforced composite material, defects such as voids are likely to occur, which is not preferable. In addition, solutions of polyamic acid, polyamide ester, etc. have high viscosity.
Moreover, since the solvent requires a high boiling point solvent such as an amide solvent, it is difficult to impregnate the reinforcing fibers and remove the solvent, making it difficult to make prepregs. Furthermore, these precursors such as polyamic acids and polyamide esters have poor stability, and prepregs obtained from them cannot be stored for long periods of time.

US Pat. No. 3,7≠j, /≠R discloses a method for producing polyimide that can be applied to fiber-reinforced composite materials.

This method involves manufacturing and molding a prepreg from an alcoholic solution of a three-component mixture of an aromatic tetracarboxylic acid alkyl ester, an aromatic diamine, and an unsaturated dicarboxylic acid alkyl ester. This method makes it easy to produce prepregs because the solution has a low viscosity, but the prepregs are not sufficiently stable and require low temperatures for long-term storage. Furthermore, during molding, a two-step reaction is required: generation of an imide oligomer, which is a precursor of polyimide, and then curing by increasing the molecular weight of this imide oligomer. At this time, water and alcohol are generated as volatile components, which can cause defects. It's easy to become. Also, the heat resistance of the cured product is good, but the curing temperature is 3.
The temperature is relatively high at around 00°C, and there are restrictions on molding equipment, auxiliary materials, etc.

Therefore, the present inventors have improved these drawbacks by creating a solvent-soluble imide oligomer that has excellent storage stability, does not generate volatile components such as water and alcohol during molding, and can be converted into a polyimide that has good heat resistance when heated. We have previously reported on the manufacturing method (Japanese Unexamined Patent Application Publication No. Shojter/ARIA No. 7). Furthermore, it has become possible to produce fiber-reinforced composite materials with excellent thermal and mechanical properties using such Indian oligomers.

[Problem that the invention seeks to solve]

However, the current situation is that these fiber-reinforced composite materials are required to have various custom-made improvements such as moldability, mechanical strength, and heat resistance. As a result of careful consideration,
By using specific amounts of specific functionalizing agents, moldability,
It was discovered that various properties such as heat resistance were further improved, and the present invention was achieved.

[Means for solving problems]

That is, an object of the present invention is to provide a solvent-soluble imide oligomer composition that can be cured at a relatively low temperature and the cured product can exhibit high heat resistance.

The purpose is to create an imide oligomer obtained by reacting three components as essential components: an aromatic tetracarboxylic acid or its derivative, a polyamine whose main component is a condensate of 0-ethylaniline and formaldehyde, and nadic acid or its derivative. (A) and a polymaleimide (B) obtained by reacting the co-component of the polyamine and maleic acid or a derivative thereof as essential components, the composition comprising:
The equivalent ratio of the end groups of the imide oligomer (A) and the polymaleimide (B) is to:tAo-i.

:90.

The imide oligomer composition of the present invention essentially contains three components: an aromatic tetracarboxylic acid or its derivative, a polyamine whose main component is a condensate of 0-ethylaniline and formaldehyde, and a terminal functionalizing agent, nadic acid or its derivative. Imide oligomer (A) obtained by reacting as a component
and 2 of the above polyamine and maleic acid or its derivative
It is composed of polymaleimide (B) obtained by reacting the components as essential components.

Aromatic tetracarboxylic acids used in the production of imide oligomer (A) include pyromellitic acid, J, J',
ψ, ψ′-benzophenonetetracarboxylic acid, J,
3', ≠, v'-diphe, nylethertetracarboxylic acid, J, 3', 4Z, #'-biphenyltetracarboxylic acid, λ, 3. A, 7-naphthalenetetracarboxylic acid, 2.3. ≠, j-thiophenetetracarboxylic acid, J, tI.

9,/0-perylenetetracarboxylic acid 1. z+-2-
His(3,≠-cycarboxyphenyl)furopane, etc., and seven or more isomers thereof are used. These aromatic tetracarboxylic acid components can be used in the form of derivatives such as lower alkyl esters and dianhydrides, but it is preferable to use dianhydrides due to their reactivity.

The polyamine used for producing the imide oligomer (A) is mainly composed of a condensate of o-ethylaniline and formaldehyde. As described in JP-A-7-3/RI-6/, 0-ethylaniline and formaldehyde are reacted in an aqueous medium in the presence of a strong inorganic acid such as hydrochloric acid or sulfuric acid at ~100°C. A condensate is obtained. In the above reaction, the diamine component 3,3
In addition to '-diethyl-≠ and Hiro'-diaminodiphenylmethane, triamine, tetramine, etc. are produced as by-products. The diamine component can be easily obtained by separating these by distillation, but in the present invention, these by-products can be used in the production of imide oligomers without being separated. However, if the amount of polyamines larger than J.
It is preferable to use 0% by weight or less, preferably 50% by weight or less. Also, by adding aniline during the condensation reaction of 〇-ethylaniline and formaldehyde, 3,
3'-diethylrug, ≠'-diaminodiphenylmethane, 3-ethyl-≠, ≠'-diaminodiphenylmethane,
A mixture of three components of Hiroshi and ≠'-diaminodiphenylmethane is obtained, which can also be effectively used in the present invention. Instead of aniline, a polyamine which is a condensation product of 0-ethylaniline and formaldehyde to which an aniline derivative without a substituent at the p-position, such as 0-)luidine or 0-chloroaniline is added, can also be used. Further, one portion of the polyamine, which is a condensation product of 0-ethylaniline and formaldehyde, may be replaced with another diamine as long as the imide oligomer produced is soluble in the organic solvent. Diamines that can be used include, for example, the formula H2N -R-NH2
(wherein R is a monovalent group having up to 30 carbon atoms and may optionally also contain oxygen, sulfur, nitrogen, silicon, phosphorus and similar inert groups). shown. Preferred examples of R include linear or branched alkylene groups, cycloalkylene groups, monocyclic or polycyclic aromatic groups, and multiple cycloalkylenes bonded via direct carbon bonds or divalent linking groups. basis,
Examples include aromatic groups. As a divalent linking group, an alkylene group having -0-1-SO2-1-8-1-CO-1/~3 carbon atoms (excluding a condensate of 0-ethylaniline and formaldehyde) etc.

Seven or more of these diamines are used in place of a part of the 0-ethylaniline condensate, but the amount used is usually less than the molar proportion of the total diamine.

The terminal functionalizing agent used in the production of imide oligomer (A) is nadic acid (!-norbornene-2,3-2 carboxylic acid) or its derivatives, but it is preferable to use nadic anhydride from the viewpoint of reactivity. preferable.

The imide oligomer (A) can be easily obtained by reacting the above-mentioned aromatic tetracarboxylic acid component, polyamine component, and nadic acid component in a solvent.

N,N-dimethylformamide, N,N-dimethylacetamide, N-methyl-2 as a solvent used in the reaction
- In addition to amide solvents such as pyrrolidone, phenols such as m-cresol, dimethyl sulfoxide, etc. can be mentioned.

The imide oligomer (A) can be easily obtained by heating a predetermined amount of each component in these solvents, or by reacting them in the presence of an imidization catalyst and a dehydrating agent, if necessary.

The proportions of these three components, aromatic tetracarboxylic acid, polyamine, nadic acid, or their derivatives, are appropriately determined depending on the purpose and in relation to physical properties.

When the polyamine is a diamine, the molar ratio of each component can generally be expressed as n/(n+/)/2, but this ratio is not necessarily strict.

That is, in order to reliably introduce the terminal functional group, an excess amount of nadic acid or its derivative can be used, and the excess can be purified and removed after the reaction. However, since the molecular weight of the imide oligomer (A) to be produced is determined by the value of n, the molar ratio of tetracarboxylic acid/diamine should be strictly controlled. Normally, the value of n is in the range /~/j, but
As the value of n increases, the molecular weight of the imide oligomer (A) produced increases, and the viscosity of the solution increases, making it difficult to manufacture prepregs. Therefore, the value of n is /~10. The molecular weight of the imide oligomer (A) is preferably too little or less.

The polyamine used for producing the polymaleimide (B) constituting the present invention is almost the same as the polyamine used for the imide oligomer (A), and is obtained by a condensation reaction of 0-ethylaniline and formaldehyde. However, since there is little possibility of gelation during the production of polymaleimide (B), polyamine components higher than triamine can also be effectively used. Conversely, using other diamines in place of a co-condensed polyamine with aniline or substituted aniline, or a part of the condensate of 0-ethylaniline and formaldehyde may reduce the solubility of the resulting polymaleimide (B). gender and is subject to restrictions. Generally, it is desirable to use only a homocondensate of 0-ethylaniline and formaldehyde.

The other resin component for producing polymaleimide (B) is maleic acid or a derivative thereof, and usually maleic anhydride is used.

Polymaleimide (B) can be obtained by reacting the polyamine and maleic anhydride in a solvent according to the conditions for producing the imide oligomer (A) described above. However, in order to increase the yield of polymaleimide, dehydrating agents,
It is preferable to carry out the reaction at low temperature in the presence of an imidization catalyst. The dehydrating agent is an organic carboxylic acid anhydride such as acetic anhydride, and the imidization catalyst is a tertiary amine, an alkali metal,
Salts such as N1, Cu, etc. are used.

The imide oligomer composition of the present invention can be obtained by mixing the above imide oligomer (A) and polymaleimide (B). It is important that the equivalent ratio of the nadic acid residue in the imide oligomer (A) and the maleic acid residue in the polymaleimide (B) is from 60:≠O to 10:90. If the equivalent ratio exceeds this range, the heat resistance of the cured product will decrease, and the reactivity will also decrease, requiring a higher molding temperature. Conversely, even if this ratio becomes small, the heat resistance of the cured product decreases, which is not preferable.

The imide oligomer (A) and polymaleimide (B) constituting the composition of the present invention are soluble in organic solvents. The solubility varies depending on the composition and molecular weight, but in addition to amide solvents used in the production of imide oligomer (A) and polymaleimide (B), acetone, ketos such as methyl ethyl ketone, tetrahydrofuran, dioxane, dimethoxyethane, etc. It is also soluble in chlorogenic solvents such as ethers, methylene chloride, and 2-dichloroethane. The two components of the present invention can be easily mixed by dissolving them in these solvents. These solutions have low viscosity, have good impregnating properties into reinforcing fibers, and are easy to manufacture into prepregs. Prepreg is usually produced by immersing reinforcing fibers in a solution containing λO-♂O in weight percent, followed by drying. The obtained prepreg has already been imidized, so it has excellent storage stability, and since no volatile matter such as water or alcohol is generated during molding, there are fewer defects, and it has excellent mechanical properties. A fiber-reinforced composite material with heat resistance can be obtained.

Since the composition of the present invention has two types of self-curing crosslinking groups, a polyimide resin with good heat resistance can be obtained by heating.

It is also soluble in organic solvents and contains various additives and reinforcing materials, such as diallyl phthalate, triallyl isocyanurate, reactive diluents such as ≠, ≠'-bis(2-allylphenol) dimethylmethane, divinylbenzene, and carbon. It is easy to mix powders, various metals, metal oxides, silica, asbestos, etc., and can be used not only for rods, FJFI reinforced composites, but also for LI
i! ρd (can be used to manufacture good adhesives, coating materials, molded products, etc.)

〔Example〕

The solvent-soluble imide oligomer composition will be specifically shown in Examples below, but as long as it does not exceed the scope of the claims,
It is not limited to this.

The curing reaction is at 230℃, 7h/c77! After curing in an oven at 270°C/hour, λ90'c for 1 hour,
Further, post-curing was performed at 320''C≠hours.The glass transition temperature (Tg) was determined by the TMA method from the change in the thermal expansion curve.

Reference Example 1 Synthesis of imide oligomer (1) 0-Ethylaniline/formaldehyde condensate (product name: Kayahard A-A, manufactured by Nippon Kaisha) was distilled under reduced pressure in a large flask equipped with a stirring bar, a thermometer, and a distillation tube. 3,3'-diethyl-≠,≠'-diaminodiphenylmethane (boiling point 2≠λ
°C/ArrrmHy)/02g(0,110-
E-ru) and N-methyl-λ-pyrrolidone (NMP) 1
00? was added and uniformly dissolved at room temperature. Then 3,3/
, ≠, Hiro'-benzophenone tetracarboxylic dianhydride (BTDA)1. ≠4y (0.2Omol) in NMP
≠rot and added to the above diamine solution. /
After stirring in a room for an hour, nadic anhydride (NA) 72.22
(0,≠Hiromol) was added to produce an amic acid oligomer. After further stirring at room temperature for λ hours, the temperature was gradually raised in an oil bath, and imidization reaction was carried out at 200° C. for 2 hours.

After the completion of the reaction, the homogeneous reaction sesame was separated into a furnace, washed twice by dispersing it in 3 tons of water, and heated at 100°C for 20 minutes.
Vacuum drying was performed for hours. The yield was almost quantitative.

In the engineered R spectrum of the obtained imide oligomer having a number average molecular weight of 10.theta., absorption due to the imide group of /7J01720CrIL was evident.

In addition, the generated imide oligomer is methyl ethyl ketone (
MFjK), tetrahydrofuran (THF), N, N-
It was dissolved in dimethylformamide (DMF) at a concentration of 30% by weight or more.

Reference example Synthesis of imide oligomer (2) Reference example/B
BTD instead of TDA t<≠, ≠t%Nk72.29
A ♂j, rit (0,27 mol) NA≠r, λF
(0.2 gmol) and performed in the same manner as in Reference Example 1 to obtain an imide oligomer with a number average molecular weight/130.

Reference Example 3 Synthesis of Polymaleimide 3,3'-diethyl-≠,≠/-diaminodiphenylmethane to2t (o, v, o mol) used in Reference Example/ was dissolved in NMP Hiro≠02. Maleic anhydride (NA)IA, 3t (0.1 mol) was gradually added to this solution to produce bismaleamic acid.

Next, acetic anhydride which is a dehydrating agent/43. J S', sodium acetate which is an imidization catalyst! , add 2 f, 70
The imidization reaction was carried out at ℃ for 7 hours.

After cooling to room temperature, the resulting homogeneous solution was poured into 3 tons of water.
to precipitate bismaleimide. After each house, it was dispersed in water and neutralized with sodium bicarbonate. F = after another λ
It was washed by dispersing it in 3 tons of water, and vacuum-dried at 50° C. for 10 hours.

The yield was almost quantitative.

The resulting 3 having two maleic acid residues per molecule,
The solubility of the bismaleimide of 3'-≠, v'-diaminodiphenylmethane (molecular weight≠7≠) was as good as that of the imide oligomer in Reference Example.

Examples/Imide oligomer λo, of reference example 1, bismaleimide of thread example 3 7.1. Nadic acid residues/ by dissolving Of in THF≠Oml and removing the solvent.
Maleic acid residue (equivalent ratio); [hereinafter simply referred to as equivalent ratio]
=jO/! An imide oligomer composition of 0 was obtained. The T2 of the cured nose of this composition was 337°C.

Example λ Reference Example/imide oligomer 20. Oft, an imide oligomer composition having an equivalent ratio of 30/70 was obtained by using the bismaleimide/7.7 r of Reference Example 3 and carrying out the same operation as in 4 actual cases/. T of the cured product of this composition? was 373°C.

Imide oligomer of Example 3, Hiro Reference Example 20. Of, bismaleimide of Reference Example 3 are respectively s, or P, / /, ♂j
2 and equivalence ratio=jO/! 0 (Example 3), 30/7
An imide oligomer composition of 0 (Example Hiroshi) was obtained. The T2 of these cured products was h32 ℃ (Example 3) and 3
3≠°C (Example≠).

Comparative example/Reference example/imide oligomer 20. Of, using bismaleimide J, 2 & t of Reference Example 3, an imide oligomer composition with an equivalent ratio of 70/3o was obtained in the same manner as in Example. T7 of the cured product of this composition was 306°C.

Comparative example λ) Reference example 205° 19°”?-20・0′・Reference I11
3 bismaleimide 2. An imide oligomer composition with an equivalent ratio of 70,730 was obtained in the same manner as in Example 1 using /ff. When this composition was cured, blistering occurred during post-curing due to insufficient curing.

Comparative Example 3 When the bismaleimide of Reference Example 3 was cured in the same manner as in Example, the T value was 370°C.

〔Effect of the invention〕

The composition of the present invention has excellent storage stability and moldability, and has good heat resistance as a fiber-reinforced bonding material, adhesive, coating material, etc.
It can be used to manufacture molded products, etc.

Claims (1)

[Claims] (1) An imide oligomer ( A) and a polymaleimide (B) obtained by reacting the above-mentioned polyamine and maleic acid or a derivative thereof as essential components, the composition comprising an imide oligomer (A) and a polymaleimide (B). An imide oligomer composition characterized in that the equivalent ratio of terminal groups of is 60:40 to 10:90.