JPH0662722B2 - Thermosetting 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,
It is also for imparting heat resistance to industrial materials in the fields requiring heat resistance such as laminates, laminated plates, and adhesives to expand the market and to expand into a wide range of new fields with new functions.

In response to such requirements, a group of synthetic resins called engineering plastics such as aromatic polyamide, polyimide, polysulfone, polyphenylene oxide, etc. have already been developed, and industrial production as a plastic having new functions different from conventional synthetic resins. The aromatic polyamide known under the name of amide is one of them.

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

All of these polyamides are classified as thermoplastic synthetic resins, and generally have a high melting point and a small difference between the melting point and the thermal decomposition temperature, so that melt molding is difficult or impossible depending on the structure. There was a difficulty.
On the other hand, polyamides of the type in which an oligomer is heat-cured have not yet been found.

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 the typical heat-resistant resins is polymer formation by addition reaction of an amide group to an unsaturated bond by a Michael reaction of dimaleimides and an 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 Problems] 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 which can be cured under mild conditions and has sufficient heat resistance, mechanical strength and chemical stability after curing, organic acid halides and aromatic diamines having an internal unsaturated group, In some cases, the aromatic dicarboxylic acid halide is further reacted in the presence of a hydrogenogen acceptor,
It was found that an unsaturated polyamide oligomer having an internal unsaturated group was obtained, which was curable in the presence of a radical generating catalyst, and the cured aromatic polyamide had the above-mentioned excellent properties. It was possible to complete the present invention by knowing that the combined use of maleimides in addition to the oligomer improves the curing rate, and the melting point can be lowered by selecting the composition of both, and such a desirable improvement can be achieved. .

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

In order to allow the reaction of the above [II] 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, the aromatic dicarboxylic acid dihalide is not used), preferably about 3 to 7 is advantageous in terms of moldability. Polymerization at 1 is not particularly required.

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.

As a convenient precursor for obtaining an organic residue having an internal unsaturated group (which means that the polymerizable unsaturated bond is inside, not at the end of the molecular chain) usable in the present invention, an organic acid halide, Examples thereof include crotonic acid chloride, styrylacetyl chloride, β-styrenesulfonyl chloride, cinnamic acid chloride, sorbic acid chloride, and the like, and crotonic acid chloride is most commonly used in terms of availability and price.

Hereinafter, the organic acid halide having an internal unsaturated group will be described by using crotonic acid chloride as a representative.

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 [II], the necessary amount of internal unsaturated organic acid halide, aromatic diamine and aromatic dicarboxylic acid halide were reacted. If a precise adjustment is needed, 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'-diamidodiphenyl sulfone, dianisidine, 2,4-toluylene diamine, 2,4 / 2,6-toluylene diamine mixture, 1,3-bis (3-aminophenoxy) benzene, etc. It is possible to use, and it is also possible to use a mixture of two or more kinds.

The aromatic polyamide oligomer obtained by this reaction can be easily selected in its composition as already used and can be molded at a temperature of 200 ° C. or lower.

The aromatic polyamide oligomer having an internal unsaturated group synthesized according to the present invention can be cured by the combined use of a radical generating catalyst, and the heat resistance can be markedly 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'-
Examples thereof include (3,3′-dimethyldiphenylmethane) bismaleimide, N, N ′-(3,3′-diphenylsulfone) bismaleimide, and a maleimide compound of an aniline-formaldehyde condensate.

The aromatic polyamide oligomer having an internal unsaturated group (including an internal unsaturated organic acid amide of an aromatic polyamine) of the present invention generally has a slow curing rate, and even when a radical generator is used as a catalyst, Although it is necessary to heat the composition to a high temperature, it is possible to improve the curing rate by adding 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 maleimide derivative as the aromatic polyamide oligomer is 10 to 200 parts by weight, preferably 10 to 100 parts by weight, based on 100 parts of the aromatic polyamide oligomer.

When the amount of maleimide added is 10 parts by weight or less, the heat resistance is good, but the drop in the melting point is small and the effect of improving the moldability is small. In addition, even if the melting point is more than 200 parts by weight, the melting point shows a substantially constant value, not only no further melting point drop is observed, but also 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 improved.

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

It is suitable to use 1 to 3 phr.

Also, the combined use of an unsaturated bond and a copolymerizable monomer is possible when the monomer dissolves the aromatic polyamide oligomer and the maleimide derivative, and in particular, when n in the above formula [I] is a small value, its application Wide range.

It goes without saying that the aromatic polyamide oligomer having an internal unsaturated group according to the present invention can 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) In a 4-neck separable flask equipped with a reflux condenser, a dropping funnel, a thermometer and a stirrer, isotalic acid dichloride.
16.92g (0.083mol), dimethylformamide (DMF)
Charge 100g and cool to below 10 ℃.

Next, 3,4'-diaminodiphenyl ether (3,4'-DAP
E) 20 g (0.1 mol), triethylamine 20.2 g (0.2 mol) and DMF 75 g are weighed and mixed, and added dropwise to a separable flask. Subsequently, 3.483 g (0.033 mol) of crotonic acid chloride 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 dropping is completed, the temperature of the reaction mixture is maintained at 10 ° C or lower, and stirring is continued for 2 hf.

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.

mp165 to 180 ° 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 placed in a 90 ° C. oil bath to evaporate the acetone to dryness.
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. The polymer was further post-cured at 200 ° C. for 5 hours.

The obtained polymer was crushed 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) 1.986 g (0.001 mol) of the oligomer [I] synthesized in Synthesis Example 1, 0.346 g (0.002 mol) of N-phenylmaleimide,
2.332 g of a 2% acetone solution of dicumyl peroxide was added to a test tube, mixed homogeneously, put in an oil bath at 90 ° C., evaporated to dryness, and then heated to 160 ° C. and heated for 3 hours. A colored, lumpy polymer was obtained. The 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, resulting in (2) in FIG.

(Example 3) 1 part by weight of the oligomer [I] synthesized in Synthesis Example 1, N, N '
-The same operation as in Example 2 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 added to the test tube and uniformly mixed.

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 (3) of FIG.

Example 4 A solution of 100 parts of the oligomer [I] synthesized in Synthesis Example 1, 100 parts of N, N′-diphenylmethane bismaleimide and 2 parts of dicumyl peroxide in 200 parts of dimethylformamide was coated with a glass cloth. After soaking, it was dried at 100 ° C. for 1 hour to prepare a prepreg. After that, several prepregs were superposed on each other and heated and pressed at a pressure of 15 kg / cm ² and a temperature of 160 ° C. for 1 hour, and then cured at 200 ° C. for 5 hours to obtain a laminated plate.

The bending strength of this laminate is 55 Kg / mm ² at 25 ° C,
At 200, it was 45 Kg / mm ² . The bending strength after heating at 230 ° C for 200 hours was 53 Kg / mm ² at 25 ° C.

(Reference Example 1) A composition obtained by adding maleimide to an aromatic polyamide oligomer has a remarkably 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 [I] obtained in Synthesis Example 1 at various mixing ratios.

[Effect] The present invention is a thermosetting polyamide resin excellent in heat resistance that does not deteriorate the mechanical properties even at high temperature without losing the excellent properties of the aromatic polyamide. An improved thermosetting resin composition could be provided.

[Brief description of drawings]

FIG. 1 is a diagram showing the results of thermogravimetric analysis of the polymers obtained in Examples 1 to 3.

Claims (4)

[Claims] 1. A thermosetting resin composition comprising: (a) an aromatic polyamide oligomer having an aliphatic unsaturated group at the terminal and represented by the general formula [I] and (b) a maleimide derivative. 2. The maleimide derivative is a maleimide derivative which is at least one of phenylmaleimide, aromatic dimaleimide and aromatic polymaleimide.
The heat-curable resin composition described. 3. The thermosetting resin composition according to claim 1, wherein the maleimide derivative is 10 to 200 parts by weight based on 100 parts by weight of the polyamide oligomer. 4. An aromatic polyamide oligomer wherein A and A'in the general formula [I] of claim 1 are CH ₃ CH = CH-, and B and B'are -CO-.