JPH0725880B2 - Aromatic polyamide oligomer having terminal unsaturated group and method for producing the same - Google Patents

Description

TECHNICAL FIELD The present invention relates to a heat-resistant synthetic resin, particularly an oligomer useful as a heat-resistant aromatic polyamide having a thermosetting property, and a method for producing the same.

[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 expanding together with the sophistication of the industrial sector.

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 industrial production as a plastic having a new function 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 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.

[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 that can be cured under mild conditions and has sufficient heat resistance, mechanical strength and chemical stability after curing,
Radical-polymerizable aliphatic monoamine, aromatic diamine, and aromatic dicarboxylic acid dihalide having a terminal unsaturated group having 3 to 5 carbon atoms in a molar ratio of 2: n: n + 1 (where n is 1 to 15)
In the presence of a hydrogen halide acceptor at a ratio of
General formula An unsaturated polyamide oligomer having a terminal unsaturated group represented by the following is obtained, which is curable in the presence of a radical generating catalyst, and the cured aromatic polyamide is found to have the above-mentioned excellent properties. The invention was completed.

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 to proceed smoothly, an acceptor of hydrogen chloride produced as a by-product is necessary, and it is generally convenient to use a tertiary amine or caustic.

In this case, a value of n of 1 to 15, preferably about 3 to 7, is advantageous in terms of moldability, and it is not particularly necessary to polymerize at this stage. In this reaction, amines are generally mixed in an aqueous phase, and acid closlide is mixed with an inert organic solvent that does not dissolve in water to carry out an interfacial polycondensation reaction, or both are dissolved in an inert organic solvent and condensed at low temperature. It can be carried out by a low temperature solution polycondensation reaction.

Examples of the aromatic diamine that can be used in the present invention include metaphenylenediamine, 4,4'-diaminodiphenylmethane, 4,4'-diaminodiphenipropane, 3,3'-dimethyl-4,4'-diaminodiphenylmethane, 4 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, etc. can be used, and a mixture of two or more kinds can be used.

Examples of the aliphatic monoamine having a terminal unsaturated group include allylamine, diallylamine, methallylamine, allylmethylamine, 1-amino-4-pentene, etc., but it is possible to synthesize a terminal unsaturated polyamide oligomer at a low temperature, Allylamine is most commonly used from the viewpoints of stability, availability, price, etc. of the polyamide oligomer. The amine may be a free amine or a halogen hydrohalide, but in the case of a hydrohalide, a tertiary amine or the like that simultaneously binds to hydrogen halide may be used in combination. Will be needed.

Hereinafter, an aliphatic amine having a terminal unsaturated group will be described by using allylamine as a representative.

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 and the like are typical.

In terms of practicality, phthalic acid dichloride has insufficient heat resistance of the produced aromatic polyamide, and when terephthalic acid dichloride is used, it has sufficient heat resistance, but the aromatic polyamide obtained has a high melting point. It tends to be difficult to handle and isophthalic dichloride is best suited for the purposes of the present invention.

Since this synthetic reaction proceeds in a relatively stoichiometric manner, after calculating n in the above formula [I], the required amount of aliphatic monoamine, aromatic diamine and aromatic dicarboxylic acid dihalide should be reacted. Of course, if a precise adjustment is needed, 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.

It is not necessary to limit the radical generation catalyst, but industrially the peroxide type is suitable and the molding temperature is 10
When the temperature is 0 ° C. or higher, a 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 applicable range thereof is wide particularly when n in the formula [I] is a small value. The combined use of monomers promotes softening of the entire condensation system and improves moldability and workability, but on the other hand, it tends to reduce the heat resistance of the cured aromatic polyamide, so the amount added should be adjusted according to the purpose. is necessary.

As a matter of course, the aromatic polyamide oligomer having an unsaturated terminal group according to the present invention can be used in combination with a reinforcing agent, a filler, a release agent, a coloring agent, another polymer as a low-shrinking agent, etc., if necessary.

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

[Example] (Example 1) Isophthalic acid dichloride 20.3 g (0.1 mol), dimethylformamide (DMF) 1 in a 4-neck separable flask equipped with a reflux condenser, a dropping funnel, a thermometer and a stirrer.
Charge 00g and cool to below 10 ℃.

Next, 8.1 g (0.075 mol) of metaphenylenediamine, 15.15 g (0.15 mol) of triethylamine, and 75 g of DMF are weighed and mixed, and added dropwise to a separable flask. Subsequently, 2.85 g (0.05 mol) of allylamine, 5.05 g (0.05 mol) of triethylamine 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 completion of the dropping, the temperature of the reaction mixture is kept at 10 ° C or lower, and stirring is continued for 2 hours.

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.

The infrared absorption spectrum of this product at mp260 ° C or higher is shown in Fig. 1.
Shown in.

The elemental analysis value was C, 70.32%: H, 4.67%: N, 11.67%, and the theoretical value was C, 70.15%: H, 4.80%: N, 11.69%.

(Examples 2 to 8) R of the aromatic diamine compound represented by the general formula H ₂ N-R-NH ₂
An aromatic polyamide oligomer having an unsaturated terminal group was synthesized by the same operation as in Example 1 except that the type and n were changed.

(Reference Example) 1 part by weight of the aromatic polyamide oligomer obtained in Example 7,
1 part by weight of dicumyl peroxide (2% acetone solution) was added to a test tube, the temperature was gradually raised, the acetone was blown off, and the test tube was dried. Then, the temperature was raised to 200 ° C., and curing was carried out for 7 hours, whereby an amber-colored tough, insoluble and infusible bulk polymer was obtained. The obtained polymer is ground in a mortar and dried in air for 10
When thermogravimetric analysis was performed at a temperature rise temperature of ℃ / min,
No change occurred up to 0 ° C, and a weight loss of about 8% was observed at 450 ° C.

[Effect] Since the conventional aromatic polyamide is a thermoplastic resin,
Although it had excellent properties such as chemical resistance and electrical properties, its strength at high temperatures was significantly reduced, limiting its fields of use.

The present invention improves these drawbacks and develops a novel aromatic polyamide oligomer having a terminal unsaturated group, which can be used as a raw material for a thermosetting aromatic polyamide which is the same aromatic polyamide but has excellent processability. Was successful.

This oligomer is excellent in that it can be synthesized at a low temperature and, despite having a polymerizable double bond, it is relatively stable, does not gel during the molding process, and can be easily cured by the action of a radical generating catalyst. It has properties.

The aromatic polyamide obtained by curing this oligomer is an aromatic polyamide having excellent heat resistance that does not cause a decrease in strength even at high temperatures.

[Brief description of drawings]

1 to 8 are aromatic polyamide oligomers obtained in Examples 1 to 8 of the present invention. It is an infrared absorption spectrum figure corresponding to the example number of.

Claims (2)

[Claims] (1) General formula [Wherein A is an aliphatic alkenyl substituent having a terminally unsaturated group having 3 to 5 carbon atoms capable of radical polymerization, R is a hydrogen atom or a lower alkyl group, and R ₁ and R ₂ are divalent aromatic groups] , N
Is an arbitrary numerical value from 1 to 15. ] The aromatic polyamide oligomer which has a terminal unsaturated group represented by these. 2. A radically polymerizable aliphatic monoamine, aromatic diamine, and aromatic dicarboxylic acid dihalide having a terminal unsaturated group having 3 to 5 carbon atoms in a molar ratio of 2: n: n + 1 (where n is 1 to 15). The method for producing an aromatic polyamide oligomer having a terminal unsaturated group, which comprises reacting in the presence of a hydrogen halide acceptor at a ratio of