JPH0667992B2 - 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,
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, polyphenylene oxide, etc. have already been developed, and industrial production as a plastic having new functions different from conventional synthetic resins. Aromatic polyamide known under the name of aramid is one of them.

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 essentially classified as thermoplastic synthetic resins, but generally have a high melting point, and some have a small difference between the melting point and the thermal decomposition temperature or they are reversed. Therefore, there is a problem that melt molding is difficult or impossible depending on the structure. On the other hand, polyamides of the type that prepares an oligomer as a precursor and heat-cures it have not been proposed yet.

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 it is attempted to homopolymerize maleimides, the polymerization reaction becomes too vigorous at high temperatures, and it is difficult to obtain useful polymers.

[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 develop an aromatic polyamide resin having improved molding processability, mechanical strength at high temperature, and improved chemical stability without losing these excellent properties of aromatic polyamide. It was done.

[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. (Meth) acrylamide (in the present invention, in order to obtain an aromatic polyamide oligomer having a sufficient heat resistance, a sufficient mechanical strength and a high chemical stability after being cured).
Means acrylamide and / or methacrylamide. ), An aromatic diamine and an aromatic dicarboxylic acid dihalide were reacted in the presence of a hydrogen halide acceptor to obtain an aromatic polyamide oligomer having a terminal unsaturated group.

It was found that this oligomer can be cured in the presence of a radical-generating catalyst, and that this cured aromatic polyamide has the above-mentioned excellent properties, but it can be cured by using maleimides in addition to this oligomer. To improve the speed and to lower the melting point of the mixture before curing by selecting the mixing ratio of both, and to obtain a molded product having sufficient heat resistance, mechanical strength and chemical stability after curing. Therefore, the present invention has been completed by finding out that the desired improvement can be made.

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 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, no aromatic diamine is used), preferably about 3 to 7 is advantageous in terms of moldability. Polymerization 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 organic acid amide having a terminal unsaturated group that can be used in the present invention include acrylamide and methacrylamide.

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.

Although 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 melting point of the aromatic polyamide oligomer obtained is high, making handling difficult. Isophthalic acid dichloride is the most suitable for the purpose of the present invention in terms of practicality.

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 it is also possible to use a mixture of two or more kinds.

Since this synthetic reaction proceeds in a relatively stoichiometric manner, after calculating n in the above formula [II], the required amount of the terminal unsaturated organic acid halide, 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.

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 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 described above are used.

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

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 (0
-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 unsaturated group at the terminal of the present invention generally has a slow curing rate, and even if a radical generator is used as a catalyst, it needs to be heated to a high temperature for a relatively long time. By compounding, the curing rate can be improved.

Furthermore, it has the effect of improving the moldability (decreasing the melting point) of the composition containing maleimide before curing, and enables processing at low pressure.

The compounding ratio of the aromatic polyamide oligomer and the maleimide derivative is 10 to 200 parts by weight, preferably 10 to 100 parts by weight, based on 100 parts by weight 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 melting point is small and the effect of improving moldability is small. Further, even if it is more than 200 parts by weight, the melting point shows a substantially constant value, not only no further decrease in melting point is observed, but also the heat resistance of the molded body is lowered, and at the same time the polymerization reaction becomes violent and it becomes difficult to control. There is a problem.

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, so-called high temperature decomposition type,
For example, dicumyl peroxide type is used.

It is suitable to use 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 under the curing reaction condition, and in particular, n in the above formula [I] is a small value. In that case, its application 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.

[Examples] (Synthesis examples 1 to 5) 500 ml equipped with reflux condenser, dropping funnel, thermometer, stirrer
In a 4-neck separable flask, 20.3 g (0.1 mol) of isophthalic acid chloride and 1 dimethylformamide (DMF)
Charge 00g and cool to below 10 ℃.

Next, a predetermined amount (0.0333 mol) of acrylamide or methacrylamide, a predetermined amount (0.0833 mol) of aromatic diamine,
Triethylamine 20.2g (0.2mol), DMF100g (or 8
0 g) is weighed and mixed and added dropwise to the reaction flask. (DMF 80g
In case of using, the dropping funnel is washed with 20 g of DMF after completion of the dropping, and the washing solution is dropped into the reaction flask. Meanwhile, the reaction temperature is kept at 10 ° C. or lower.

After completion of the dropping, the temperature of the reaction mixture is kept at 10 ° C or lower and stirring is continued for 2 hours.

Next, 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.

(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 into a test tube and mixed uniformly. The mixture was placed in a 90 ° C. oil bath, and acetone was evaporated to dryness.
The mixture was then a 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.

95% weight holding temperature 298 ° C 90% weight holding temperature 334 ° C 500 ° C weight holding ratio 61.0% (Example 2) 1 part by weight of the oligomer [I] synthesized in Synthesis Example 1, N, N '
-The same operation as in Example 1 was carried out except that 1 part by weight of diphenylmethane bismaleimide and 2 parts by weight of a 2% acetone solution of dicumyl peroxide were added into a test tube, uniformly mixed, and heated at 160 ° C for 3 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.

95% weight retention temperature 369 ° C 90% weight retention temperature 418 ° C 500 ° C weight retention 76.0% (Example 3) Instead of the oligomer [I] synthesized in Synthesis Example 1, the oligomer [II] synthesized in Synthesis Example 2 was used. Example 2 except that it was used
The same operation was performed.

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.

95% weight holding temperature 282 ° C 90% weight holding temperature 344 ° C 500 ° C weight holding rate 57.5% (Example 4) Instead of the oligomer [I] synthesized in Synthesis Example 1, the oligomer [III] synthesized in Synthesis Example 3 was used. The same operation as in Example 2 was performed except that it was used.

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 (4) in FIG.

95% weight holding temperature 318 ° C. 90% weight holding temperature 420 ° C. 500 ° C. weight holding ratio 74.3% (Example 5) Instead of the oligomer [I] synthesized in Synthesis Example 1, the oligomer [IV] synthesized in Synthesis Example 4 was used. Example 2 except that it was used
The same operation was performed.

The obtained polymer was ground in a mortar and subjected to thermogravimetric analysis in air at a temperature rising rate of 10 ° C./min to give the following values.

95% weight holding temperature 353 ° C. 90% weight holding temperature 428 ° C. 500 ° C. weight holding ratio 75.1% (Example 6) Instead of the oligomer [I] synthesized in Synthesis Example 1, the oligomer [V] synthesized in Synthesis Example 5 was used. Example 2 except that it was used
The same operation was performed.

The obtained polymer was ground in a mortar and subjected to thermogravimetric analysis in air at a temperature rising rate of 10 ° C./min to give the following values.

95% weight holding temperature 325 ° C 90% weight holding temperature 420 ° C 500 ° C weight holding ratio 73.2% (Example 7) 40 parts of the oligomer [I] synthesized in Synthesis Example 1, 40 parts of N, N'-diphenylmethane bismaleimide and A glass cloth was immersed in a solution prepared by dissolving 1.6 parts of dicumyl peroxide in 120 parts of DMF, and then dried at 80 ° C. for 1 hour to prepare a prepreg. After that, pile up several prepregs and apply pressure of 15Kg.
/ Cm ^{2 at} a temperature of 160 ℃ for 1 hour and then press at 200 ℃ for 5 hours
It was cured for a period of time to obtain a laminated plate.

The flexural strength of this laminate was 54 kg / mm ² at 25 ° C and 45 kg / mm ² at 200 ° C. Also, 230
The bending strength after heating at 25 ° C for 200 hours was 52 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, Table 1 shows melting points of N-phenylmaleimide and the oligomer [I] obtained in Synthesis Example 1 at various mixing ratios.

[Effects] The present invention is a thermosetting polyamide resin excellent in heat resistance that does not lose the excellent properties of aromatic polyamide and does not deteriorate in mechanical properties even at high temperatures, and particularly improves curability and processability. It was possible to provide the curable resin composition.

[Brief description of drawings]

FIG. 1 shows the effect of thermogravimetric analysis of the cured resin compositions of Examples 1-4.

Claims (3)

[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 thermosetting 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.