JPH0725882B2 - Unterminated unsaturated group-containing aromatic polyamide oligomer and method for producing the same - Google Patents

Description

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

[Prior Art] As the demand for the plastics industry has become more sophisticated, industrial materials with special properties have become necessary, and this tendency is rapidly expanding in conjunction with the sophistication of the industrial sector.

The demands for improved heat resistance include plastics, films, fibers,
It 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 considered that its melting point was generally sufficiently higher than that of conventional thermoplastic synthetic resins, and that it was judged that the introduction of unsaturated bonds had a large risk of causing undesirable 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 develop a raw material for producing an aromatic polyamide having improved molding processability without losing the excellent properties of these conventional polyamides, and further improved mechanical strength and chemical stability at high temperature. It is what

[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 having sufficient heat resistance, mechanical strength and chemical stability after curing, maleimide or citraconic acid imide, aromatic diamine and aromatic dicarboxylic acid dihalide can be obtained. The molar ratio 2: n: n
The reaction is conducted in the presence of a hydrogen halide acceptor at a ratio of +1 (where n is 1 to 15) to give a compound of the general formula An unsaturated polyamide oligomer having a terminal unsaturated group represented by was obtained.

This compound can be cured in the presence of a radical generating catalyst, and it was found that this cured aromatic polyamide has the above-mentioned excellent properties, and the present invention has been completed.

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

In order to allow the above reaction to proceed smoothly, an acceptor of hydrogen chloride produced as a by-product is required, and it is generally convenient to use a tertiary amine or caustic.

In this case, an oligomer having n of 1 to 15, preferably about 3 to 7, is advantageous in terms of moldability and is not required to be polymerized at this stage. 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 diamine that can be used in the present invention include metaphenone diamine, 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 and the like can be used, and a mixture of two or more kinds can also be used.

Maleimide and citraconic acid imide are used as precursors of organic residues having terminal unsaturated groups.

As the aromatic dicarboxylic acid dihalide that can be used in the present invention, a dichloride of an aromatic dibasic acid is convenient, and typical examples thereof include terephthalic acid dichloride, isophthalic acid dichloride, phthalic acid dichloride and mixtures thereof.

Aromatic polyamides derived from phthalic acid dichloride have slightly poor heat resistance, and when terephthalic acid dichloride is used, the heat resistance of the polymer after thermosetting is sufficient, but the aromatics obtained as precursors The polyamide oligomer tends to have a high melting point and becomes difficult to handle, and in terms of practicality, isophthalic acid dichloride has the best balanced property, which is consistent with the object of the present invention.

Since this synthetic reaction proceeds in a relatively stoichiometric manner, it is sufficient to calculate n in the above formula [A] and then react the required amount of maleimide, aromatic diamine and aromatic dicarboxylic acid dihalide. If a 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 this composition and can be easily molded at a temperature of 200 ° C. or lower.

The aromatic polyamide oligomer having a terminal 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 radical generating catalyst does not need to be limited, but industrially the perocide type is suitable and the molding temperature is 10
When the temperature is 0 ° 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.

Also, the combined use of the unsaturated bond of the oligomer of the present invention and the copolymerizable monomer is possible when the monomer dissolves the aromatic polyamide oligomer, and particularly when n in the formula [A] is a small value, Flexible. 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.

In the production of a molded article using the aromatic polyamide oligomer having an unsaturated end group according to the present invention, a reinforcing agent,
Needless to say, other polymers such as a filler, a release agent, a colorant, and a low-shrinking agent can be used in combination as required.

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

[Example] (Example 1) 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, 3.233 g (0.0333 mol) of maleimide and 16.67 g (0.0833 mol) of 3.4'-diaminodiphenyl ether (3.4'-DAPE).
Mol), 20.2 g (0.2 mol) of triethylamine, and 80 g of DMF are weighed and mixed, and added dropwise to the reaction flask. Meanwhile, the reaction temperature is kept below 10 ° C.

After completion of the dropping, the dropping funnel is washed with 20 g of DMF, and the washing solution is added to the reaction flask.

Further, while maintaining the temperature of the reaction mixture at 10 ° C. or lower, 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.

mp180-190 ℃, the infrared absorption spectrum of this product
Shown in the figure.

Elemental analysis values were C, 70.80%; H, 3.91%; N, 8.39%, and theoretical values were in good agreement with C, 70.52%; H, 3.95%; N, 8.51%.

(Example 2) 500 ml equipped with reflux condenser, dropping funnel, thermometer, stirrer
Charge 20.3 g (0.1 mol) of isophthalic acid chloride and 100 g of DMF into a 4-neck separable flask and cool to 10 ° C or lower.

Next, 3.233 g (0.0333 mol) of maleimide, 20.67 g (0.0833 mol) of 3,3′-diaminodiphenyl sulfone, 20.2 g (0.2 mol) of triethylamine and 80 g of DMF are weighed and mixed, and added dropwise to the reaction flask.

After completion of the dropping, the container and the dropping funnel are washed with 20 g of DMF, and the washing solution is added to the reaction flask. Meanwhile, the reaction temperature is 10
Keep below ℃.

After the addition is complete, stirring is continued for 2 hours, keeping the temperature of the reaction mixture below 10 ° C.

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.

mp160-172 ℃, the infrared absorption spectrum of this product
Shown in the figure.

The elemental analysis values were C, 62.98%; H, 3.49%; N, 7.51%, and the theoretical values were in good agreement with C, 62.87%; H, 3.52%; N, 7.59%.

(Example 3) The same operation as in Example 2 was carried out except that 18.83 g (0.0833 mol) of 3,3'-dimethyl-4.4'-diaminodiphenylmethane was used instead of 20.67 g (0.0833 mol) of 3,3'-diaminodiphenyl sulfone.

mp165-190 ℃, the infrared absorption spectrum of this product
Shown in the figure.

The elemental analysis values were C, 74.89%; H, 5.08%; N, 7.81%, and the theoretical values were in good agreement with C, 74.71%; H, 5.13%; N, 7.98%.

(Example 4) 500 ml equipped with reflux condenser, dropping funnel, thermometer, stirrer
Charge 20.3 g (0.1 mol) of isophthalic acid chloride and 100 g of DMF into a 4-neck separable flask and cool to 10 ° C or lower.

Then maleimide 2.425 g (0.025 mol), 3,4'-DAPE 17.5
g (0.0875 mol), triethylamine 20.2 g (0.2 mol), and DMF80 g are weighed and mixed, and added dropwise to the reaction flask.

After completion of the dropping, the dropping funnel is washed with 20 g of DMF, and the washing solution is added to the reaction flask. During that time, the reaction temperature is kept below 10 ° C.

After the addition is complete, stirring is continued for 2 hours, keeping the temperature of the reaction mixture below 10 ° C.

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.

mp185-197 ℃, the infrared absorption spectrum of this product
Shown in the figure.

Elemental analysis values were C, 71.29%; H, 3.97%; N, 8.41%, and theoretical values were in good agreement with C, 71.07%; H, 4.02%; N, 8.50%.

[Effect] Conventional aromatic polyamide is a thermoplastic resin,
Although it had excellent properties such as chemical resistance and electrical characteristics due to its high melting point, it had a problem in moldability and the mechanical strength at high temperature was significantly reduced, so it was below the melting point or decomposition point. Even in the temperature range, the field of use was limited. The present invention has improved these drawbacks and is a novel end-capping compound which can be used as a raw material for a thermosetting aromatic polyamide, which is the same aromatic polyamide but is excellent in moldability and has little decrease in mechanical strength even at high temperatures. We have succeeded in developing an aromatic polyamide oligomer having a saturated group.

Although this oligomer can be synthesized at low temperature and has a double bond that can be polymerized, it is relatively stable and does not gel during the molding process. It has an excellent property that it can be hardened to.

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 4 are infrared absorption spectrum diagrams of the aromatic polyamide oligomers having terminal unsaturated groups obtained in Examples 1 to 4, respectively.

Claims (2)

[Claims] 1. A general formula [Wherein R ₁ and R ₂ are divalent aromatic groups, R ₃ is H or CH ₃
Represents a group selected from, and n is an arbitrary value of 1 to 15. ] A terminal unsaturated group-containing aromatic polyamide oligomer represented by: 2. A maleic or citraconic acid imide, an aromatic diamine and an aromatic dicarboxylic acid dihalide are used in a molar ratio.
A process for producing an aromatic polyamide oligomer containing a terminal unsaturated group, which comprises reacting in the presence of a hydrogen halide acceptor at a ratio of 2: n: n + 1 (where n is 1 to 15).