JPH0643475B2 - Curable resin composition - Google Patents

Description

TECHNICAL FIELD The present invention relates to a heat-resistant synthetic resin, and particularly to a heat-resistant thermosetting resin composition having excellent processability.

[Prior Art] As the demand of the plastics industry has become more sophisticated, industrial materials having special properties have been required, and this tendency is rapidly developing in combination with the sophistication of the technology.

The demands for improved heat resistance include plastics, films, fibers,
This is also to impart heat resistance to industrial materials in the fields where heat resistance is required, such as laminates, laminates and adhesives, to expand the market and to expand into new fields with new functions.

In response to such requirements, a group of synthetic resins called engineering plastics such as aromatic polyamide, polyimide, polysulfone, and polyphenylene oxide have already been developed, and as a plastic having a new function different from conventional synthetic resins. One of them is the aromatic polyamide, which is industrially produced and is opening up new demand fields, and is known by the name of aramid.

As aromatic polyamides, polyparaphenylene terephthalamide (trade name: Kepler) and polymetaphenylene isophthalamide (trade name: developed by Du Pont).
Nomex or HT-1) is a typical type.

All of these polyamides are classified as thermoplastic synthetic resins, and polyamides of the type in which an oligomer is thermoset have not been found yet.

For this reason, although it has a higher melting point than ordinary thermoplastic synthetic resins, a decrease in hardness, strength, etc. is inevitable as the temperature rises, and it is practically impossible to use above the softening point. there were.

The reason why there was no thermosetting aromatic polyamide was
It is generally considered that the melting point was sufficiently higher than that of the conventional thermoplastic synthetic resin, and that it was judged that the introduction of the unsaturated bond had a large risk of causing undesired gelation during the molding process.

On the other hand, apart from this, it is also well known that one of typical heat-resistant resins is polymer formation by addition reaction of amino group to unsaturated bond by Michael reaction of dimaleimides and aromatic diamine ( France, Rhône-Poulin'Cerimide ').

However, when maleimides are subjected to homopolymerization, the polymerization reaction becomes too vigorous at high temperatures, and useful polymers cannot be obtained.

[Problems to be Solved by the Invention] Aromatic polyamide is a heat-resistant polymer that is relatively stable even at a considerably high temperature, has excellent electrical properties and mechanical strength, and has high chemical stability. .

The present invention aims to further increase mechanical strength and chemical stability at high temperatures without losing these properties.

[Means for Solving the Problem] The present inventors have a relatively low melting point when molding as a molding material or a laminated plate, and can be molded into a desired shape under heating and pressurization. In order to obtain an aromatic polyamide oligomer that can be cured under mild conditions and has sufficient heat resistance, mechanical strength, and chemical stability after curing, aromatic monoamines and aromatic dicarboxylic acid dihalides having terminal unsaturated groups are obtained. , Optionally further reacting an aromatic diamine in the presence of a hydrogen halide acceptor to give an unsaturated polyamide oligomer having terminal unsaturated groups, which is curable in the presence of a radical generating catalyst It was found that the cured aromatic polyamide has the above-mentioned excellent properties, and in addition to this oligomer, maleimides were added. The present invention has been completed by knowing that the combined use can improve the curing rate and can lower the melting point by selecting the composition of both, and the desired improvement can be achieved.

The aromatic polyamide oligomer having a terminal unsaturated group of the present invention can be represented by the following reaction formula as an example.

In order to allow the reaction [A] to proceed smoothly, a hydrogen chloride acceptor, which is a by-product, is required, and it is generally convenient to use an aliphatic tertiary amine or caustic alkali.

In this case, n is about 0 to 15 (however, when n = 0, aromatic diamine is not used), preferably 3 to 7.
A certain value is advantageous in terms of ease of moldability, and polymerizing at this stage is not particularly necessary.

In this reaction, amines are generally mixed in an aqueous phase and acid chloride is mixed with an inert organic solvent which is insoluble in water to carry out an interfacial polycondensation reaction, or both are dissolved in an inert organic solvent and condensed at a low temperature. It can be carried out by a low temperature solution polycondensation reaction.

Examples of the aromatic monoamine having a terminal unsaturated group that can be used in the present invention include m-isopropenylaniline, p-isopropenylaniline, o-aminostyrene, m-aminostyrene, p-aminostyrene, etc. In terms of sex, price, etc., m-isopropenylaniline, p
-Isopropenylaniline, p-aminostyrene is most commonly used. The amine may be a free amine or a hydrohalide,
In the case of a hydrohalide salt, it is necessary to use a tertiary amine or the like that simultaneously binds with hydrogen halide.

Further, as the aromatic dicarboxylic acid dihalide that can be used in the present invention, a dichloride of an aromatic dibasic acid is convenient, and for example, terephthalic acid dichloride, isophthalic acid dichloride, phthalic acid dichloride or a mixture thereof is typical.

In terms of practicality, phthalic acid dichloride has insufficient heat resistance of aramid after curing, and when terephthalic acid dichloride is used, it has sufficient heat resistance, but the obtained aromatic polyamide oligomer has a high melting point. Therefore, the handling property tends to be difficult, and isophthalic acid dichloride is most suitable for the purpose of the present invention.

Since this synthetic reaction proceeds in a relatively stoichiometric manner, after calculating n in the above formula [A], the required amount of terminal unsaturated aromatic monoamine, aromatic diamine and aromatic dicarboxylic acid dihalide was calculated. The reaction can be carried out, and if precise adjustment is required, the molar ratio can be determined by a simple test.

Examples of aromatic diamines include metaphenylenediamine, 4,4′-diaminodiphenylmethane, 4,4′-diaminodiphenylpropane, 3,3′-dimethyl-4,4′-diaminodiphenylmethane, 4,4′-diaminodiphenyl ether. , 3,4'-diaminodiphenyl ether, 3,3'-
Diaminodiphenyl sulfone, 4,4'-diaminodiphenyl sulfone, dianisidine, 2,4-toluylenediamine, 2,4 / 2,6-toluylenediamine mixture, 1,3-bis (3-aminophenoxy) benzene, etc. It is possible to use, and a mixed use of two or more kinds is also possible.

As described above, the aromatic polyamide oligomer obtained by this reaction can be easily selected in its composition and can be molded at a temperature of 200 ° C. or lower.

The aromatic polyamide oligomer having an unsaturated terminal group synthesized by the present invention can be cured by heat curing or by using a radical generating catalyst in combination, and the heat resistance can be remarkably improved.

The maleimides used in combination with the aromatic polyamide oligomer are classified into the following three types.

(i) Phenylmaleimides (ii) Dimaleimides synthesized from aromatic diamine and maleic anhydride The types of aromatic diamines mentioned above are used.

(iii) Polymaleimide synthesized from aniline-formaldehyde condensate and maleic anhydride Furthermore, (i), (ii) and (iii) can be used in combination.

Phenylmaleimide has a low melting point and has a wide compatibility with aromatic polyamide oligomers, but it also has a slight lack of heat resistance. Generally, dimaleimides made from aromatic diamine are used.

Examples of these are N-phenylmaleimide, N-
(O-chlorophenyl) maleimide, N, N'-diphenylmethane bismaleimide, N, N'-diphenyl ether bismaleimide, N, N'-paraphenylene bismaleimide, N, N '-(2-methylmetaphenylene) bismaleimide, N, N'-metaphenylene bismaleimide, N, N '-(3,3'-dimethyldiphenylmethane)
Examples thereof include bismaleimide, N, N ′-(3,3′-diphenylsulfone) bismaleimide, and a maleimide compound of an aniline-formaldehyde condensate.

The aromatic polyamide oligomer having an unsaturated group at the terminal (including phthalamide such as diallyl isophthalamide) of the present invention generally has a slow curing rate and is heated to a high temperature for a long time even if a radical generator is used as a catalyst. However, the curing rate can be improved by incorporating a maleimide derivative.

Furthermore, there is an effect of improving the moldability (decreasing the melting point) of the composition containing maleimide before curing, and an effect of enabling processing at a low pressure.

The compounding ratio of the aromatic polyamide oligomer and the maleimide derivative is 10 to 200 parts by weight, preferably 10 to 1 part by weight of the maleimide derivative with respect to 100 parts of the aromatic polyamide oligomer.
It is 00 parts by weight.

When the amount of maleimide added is 10 parts by weight or less, the heat resistance is good, but the drop in melting point is small and the effect of improving moldability is small. Further, even if the amount is 200 parts by weight or more, the melting point shows a substantially constant value, and no further decrease in melting point is observed, and further, the heat resistance is lowered, and at the same time, the polymerization reaction becomes violent and uncontrollable. There is.

The mixture of the aromatic polyamide oligomer and the maleimides according to the present invention can be cured by using a radical generating catalyst in combination, and the heat resistance can be markedly improved.

The radical generating catalyst does not need to be limited, but when the molding temperature is 100 ° C. or higher, a so-called high temperature decomposition type, for example, dicumyl peroxide type is used.

Appropriate amount of use is 1 to 3 phr.

Further, the combined use of the unsaturated bond and the copolymerizable monomer is possible when the monomer dissolves the aromatic polyamide oligomer and the maleimide derivative, and particularly when n in the formula [A] is a small value, its applicable range Is wide.

The aromatic polyamide oligomer having an unsaturated terminal group according to the present invention can, of course, be used in combination with a reinforcing agent, a filler, a release agent, a colorant, a polymer, etc., if necessary.

Next, in order to help understanding of the present invention, examples will be shown below.

[Example] (Synthesis example 1) Into a four-necked separable flask equipped with a reflux condenser, a dropping funnel, a thermometer, and a stirrer was charged 20.3 g (0.1 mol) of isophthalic acid dichloride and 100 g of dimethylformamide (DMF), and 10 ° C. Cool to:

Next, 16.67 g of 3,4'-diaminodiphenyl ether
(0.083 mol), 16.87 g of triethylamine
(0.167 mol) and 75 g of DMF are weighed and mixed, and added dropwise to a separable flask.

Subsequently, 4.43 g of p-isopropenylaniline (0.0
33 mol), 3.33 g of triethylamine (0.033
Mol) and 25 g of DMF are weighed and mixed, and added dropwise to a separable flask. Meanwhile, the temperature of the reaction mixture is kept below 10 ° C. After the completion of dropping, the temperature of the reaction mixture was kept at 10 ° C. or lower for 2 hr. Continue stirring.

Then, the reaction mixture is gradually added to a large amount of water with vigorous stirring to precipitate crystals. The precipitated crystals are suction filtered, washed with water and dried.

m. p. 170-185 ° C (Synthesis example 2) Instead of 4.43 g (0.033 mol) of p-isopropenylaniline, 4.43 g of m-isopropenylaniline
The same method was used as in Synthesis Example 1 except that (0.033 mol) was used.

m. p. 170-185 ° C (Synthesis example 3) Instead of 4.43 g (0.033 mol) of p-isopropenylaniline, 3.97 g (0.0
The same procedure as in Synthesis Example 1 was performed except that 33 mol) was used.

m. p. 180-192 ° C (Synthesis example 4) 3,4'-diaminodiphenyl ether 16.67g
2,4-toluylenediamine / 2,6-toluylenediamine mixture (80:20) 1 instead of (0.083 mol)
Same as Synthesis Example 1 except that 0.17 g (0.083 mol) and p-aminostyrene 3.97 g (0.033 mol) were used instead of p-isopropenylaniline 4.43 g (0.033 mol). By the way.

m. p. 190 to 205 ° C. (Example 1) 1 part by weight of the oligomer [I] synthesized in Synthesis Example 1, 1 part by weight of N-phenylmaleimide, and 2 parts by weight of a 2% acetone solution of dicumyl peroxide were added to a test tube and homogenized. And mixed in a 90 ° C. oil bath to evaporate and dry the acetone.

The mixture was then a slightly cloudy yellow homogeneous solution.

When this yellow homogeneous solution was heated to 120 ° C. and heated for 3 hours, an amber-colored tough lump polymer was obtained.
This polymer was further post-cured at 200 ° C. for 5 hours.

The obtained polymer was pulverized in a mortar and subjected to thermogravimetric analysis in air at a temperature rising rate of 10 ° C./min to give (1) in FIG.

Example 2 The same operation as in Example 1 except that 1 part by weight of the oligomer [II] synthesized in Synthesis Example 2, 1 part by weight of N-phenylmaleimide, and 2 parts by weight of a 2% acetone solution of dicumyl peroxide were used. Was done.

The obtained polymer was crushed in a mortar and thermogravimetric analysis was performed in air at a temperature rising rate of 10 ° C./min, and the result was as shown in (2) of FIG.

(Example 3) 2.05 g of the oligomer [II] synthesized in Synthesis Example 2 (0.
001 mol), N-phenylmaleimide 0.35 g
(0.002 mol) and the same operation as in Example 1 was carried out except that 2.4 g of a 2% acetone solution of dicumyl peroxide was used.

The obtained polymer was pulverized in a mortar and thermogravimetric analysis was performed in air at a temperature rising rate of 10 ° C./min to give (3) in FIG.

(Example 4) 1 part by weight of the oligomer [I] synthesized in Synthesis Example 1, N, N '
The same operation as in Example 1 was performed except that 1 part by weight of diphenylmethane bismaleimide and 2 parts by weight of a 2% acetone solution of dicumyl peroxide were used.

The obtained polymer was pulverized in a mortar and thermogravimetric analysis was performed in air at a temperature rising rate of 10 ° C./min, resulting in (1) in FIG.

(Example 5) 1 part by weight of the oligomer [II] synthesized in Synthesis Example 2, N, N '
The same operation as in Example 1 was performed except that 1 part by weight of diphenylmethane bismaleimide and 2 parts by weight of a 2% acetone solution of dicumyl peroxide were used.

The obtained polymer was pulverized in a mortar and thermogravimetric analysis was performed in air at a temperature rising rate of 10 ° C./min, and the result was as shown in (2) of FIG.

(Example 6) 1 part by weight of the oligomer [III] synthesized in Synthesis Example 3, N, N '
The same operation as in Example 1 was performed except that 1 part by weight of diphenylmethane bismaleimide and 2 parts by weight of a 2% acetone solution of dicumyl peroxide were used.

The obtained polymer was pulverized in a mortar and thermogravimetric analysis was performed in air at a temperature rising rate of 10 ° C./min, resulting in (3) in FIG.

(Example 7) 1 part by weight of the oligomer [IV] synthesized in Synthesis Example 4, N, N '
The same operation as in Example 1 was performed except that 1 part by weight of diphenylmethane bismaleimide and 2 parts by weight of a 2% acetone solution of dicumyl peroxide were used.

The obtained polymer was crushed in a mortar and thermogravimetric analysis was performed in air at a temperature rising rate of 10 ° C./min to give (4) in FIG.

(Example 8) 50 parts by weight of the oligomer [II] synthesized in Synthesis Example 2, N,
A glass cloth is immersed in a solution prepared by dissolving 50 parts by weight of N'-diphenylmethane bismaleimide and 1.5 parts of dicumyl peroxide in 100 parts of dimethylformamide, and then air-dried overnight at room temperature. Then, it was dried at 100 ° C. for 1 hour to prepare a prepreg. After that, several prepregs were piled up and pressure was set to 15 kg / cm ^{2 at} a temperature of 160 ° C.
After heating and pressing for an hour, post-curing was performed at 200 ° C. for 5 hours to obtain a laminated plate.

Flexural strength of the laminate is 56kg / mm ² at 25 ° C., in a 200 ° C. was 46 kg / mm ^2. The flexural strength after heating at 230 ° C. for 200 hours was 55 kg / mm ² at 25 ° C.

Reference Example 1 A composition obtained by adding maleimides to an aromatic polyamide oligomer has a significantly lowered melting point and is easily processed.

As an example of this, Table 1 shows melting points of N-phenylmaleimide, N, N'-diphenylmethane bismaleimide and the oligomer [III] obtained in Synthesis Example 2 at various mixing ratios.

[Effects] A group of aromatic polyamides called aramids has been highly evaluated as an engineering plastic excellent in mechanical properties and chemical resistance, but it has a difficulty in moldability and also has high heat resistance. Although excellent, it suffered from deterioration of mechanical properties at high temperatures.

The present invention solves both of these problems at once by developing a thermosetting aromatic polyamide oligomer and by using a resin composition of this oligomer and a maleimide derivative.

That is, the processability was dramatically improved by using a thermosetting aromatic polyamide oligomer, but by using a maleimide derivative in combination with this, the melting point of the aromatic polyamide oligomer was lowered and molding processability was further improved. We have developed a curable resin composition that, while improving, can be sufficiently cured even under mild conditions (improvement in curing speed), and that provides high heat resistance, chemical resistance, and excellent mechanical properties at high temperatures after curing. did.

[Brief description of drawings]

FIG. 1 shows thermogravimetric analysis in air of the polymer synthesized in Example, (1) shows Example 1,
(2) shows the results of Example 2 and (3) shows the results of Example 3. FIG. 2 shows that (1) is the fourth embodiment, (2) is the fifth embodiment,
(3) shows thermogravimetric analysis in air of the polymer synthesized in Example 6 and (4).

Claims (3)

[Claims] 1. A general formula An aromatic polyamide oligomer represented by. (B) A curable resin composition containing a maleimide derivative. 2. The maleimide derivative according to claim 1, wherein the maleimide derivative is at least one of phenylmaleimide, aromatic dimaleimide and aromatic polymaleimide. 3. The maleimide derivative according to claim 1, wherein the amount of the maleimide derivative is 10 to 2 with respect to 100 parts by weight of the polyamide oligomer.
Curable resin composition which is 00 parts by weight.