JPH03277629A - Aromatic polyamide oligomer and its production - Google Patents

Abstract

PURPOSE:To obtain an aromatic polyamide oligomer for use as a material in the production of an aromatic polyamide improved in moldability without detriment to the excellent properties inherent in polyamide and improved in mechanical strengths at high temperatures and chemical stability by forming a specified aromatic polyamide oligomer terminated with a cyclic unsaturated group. CONSTITUTION:A cyclic unsaturated group-terminated aromatic polyamide oligomer represented by formula I (wherein R1 and R2 are each a bivalent aromatic group; R3 is a bivalent aliphatic or aromatic group; A and B are each an aliphatic unsaturated group (A may be the same as B); and n is an arbitrary number of 1-15). Examples of the aliphatic unsaturated groups in formula I include -CH=CH- and groups of formulas II, III, IV and V. The above oligomer can be obtained by reacting an aromatic diamine, an aromatic dicarboxylic dihalide, an N-(hydroxyphenyl) cyclic unsaturated imide or an N-(hydroxyalkyl) cyclic unsaturated imide in the presence of a hydrogen halide acceptor.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application 1] The present invention relates to an oligomer useful as a raw material for a heat-resistant synthetic resin, particularly a heat-resistant aromatic polyamide imparted with thermosetting properties, and a method for producing the oligomer.

[Prior Art] As the demands of the plastics industry become more sophisticated, industrial materials with special properties are required, and this trend is rapidly developing as the industrial sector becomes more sophisticated.

The demand for improved heat resistance is felt in plastics, films, fibers,
The aim is to add heat resistance to industrial materials in fields that require heat resistance, such as laminates, laminates, and adhesives, to expand the market, and to expand into a wide range of new fields with new functions.

In response to these demands, a group of synthetic resins called engineering plastics, such as aromatic polyamides, polyimides, polysulfones, and polyphenylene oxides, have already been developed. Aromatic polyamides, known as aramids, are one of them, and are being industrially produced as polyamides and are opening up new fields of demand.

Examples of aromatic polyamides include polybaraphenylene terephthalamide (product name: Kevlar) and polymetaphenylene isophthalamide (product name:
Nomex or HT-1) is a typical type.

All of these polyamides are essentially classified as thermoplastic synthetic resins, but they generally have a high melting point, and in some cases the difference between the melting point and the thermal decomposition temperature is small or reversed. Therefore, melt molding is difficult or impossible depending on the structure. On the other hand, a type of polyamide in which an oligomer is made as a precursor and then heat-cured has not yet been proposed6.
The reason why there was no thermosetting aromatic polyamide was as follows.
- This is thought to be because its melting point was statistically much higher than that of conventional thermoplastic synthetic resins, and the introduction of unsaturated bonds was considered to have a high risk of causing undesirable gelation during the molding process. .

[Problem to be solved by the invention] Aromatic polyamide is an excellent heat-resistant polymer that is relatively stable even at considerably high temperatures, has excellent electrical properties and mechanical strength, and has high chemical stability. .

The purpose of the present invention is to develop raw materials for producing aromatic polyamides that have improved moldability without losing the excellent properties of these conventional polyamides, as well as improved mechanical strength and chemical stability at high temperatures. That is.

[Means for Solving the Problems 1] The present inventors found that when molding as a molding material or as a laminate, it has a relatively low melting point, can be molded into a desired shape under heat and pressure, and is 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, aromatic diamines and aromatic dicarboxylic acid dihalides are used as hydrogen halide acceptors. R in the general formula.

2 is a divalent aromatic group, and an unsaturated polyamide oligomer having a polymerizable cycloaliphatic unsaturated group at the terminal represented by 2 was obtained.

This material can be cured in the presence of a radical-generating catalyst, and the inventors discovered that this cured aromatic polyamide has the above-mentioned excellent properties, leading to the completion of the present invention.

The aromatic polyamide oligomer having unsaturated groups of the present invention can be synthesized by the following reaction formula, for example.

(Left below) 1 N-ip-hydroquinphenyl)7reimide (cyclic unsaturated imide) Metaphenylenediamine (aromatic diamine) Isophthalic acid dichloride (aromatic dicarboxylic acid dihalide) 1 (Aromatic polyamide oligomer) Smoothes the above reaction In order to proceed, an acceptor for the by-product hydrogen chloride is required, and numerically it is convenient to use a tertiary amine or a caustic alkali.

In this case, oligomers with a value of n of about 1 to 15, preferably about 3 to 7, are advantageous because of their ease of moldability, and polymerization at this stage is not necessary at all.This reaction generally involves converting amines into an aqueous phase. Alternatively, an interfacial polycondensation reaction may be carried out by mixing the acid chloride with an inert organic solvent that does not dissolve in water.
Alternatively, it can be carried out by a low-temperature solution polycondensation reaction in which both are dissolved in an inert organic solvent and condensed at a low temperature.

Aromatic diamines that can be used in the present invention include:

For example, metaphenylene diamine, 4,4'-diaminodiphenylmethane, 4,4'-diaminodiphenylpropane, 3,3'-dimethyl-4,4'-diaminodiphenylmethane, 4,4'-diaminodiphenyl ether,
3.4'-diaminodiphenyl ether, 3.3'-diaminodiphenylsulfone, 4,4'-diaminodiphenylsulfone, dianisidine, 2.4-tolylenediamine, 2.4/2.6-tolylenediamine mixture, 1 3-bis(3-aminophenoxy)benzene and the like can be used, and two or more types can be used in combination.

As a precursor of an organic residue having a terminal unsaturated group, for example, N-(m-hydroxyphenylphosphomaleimide, N-
(p-hydroxyphenyl)maleimide.

N-(m-hydroxyphenyl)3.6-endomethylene-1,2,3,6-tetrahydrophthalimide, N-(p-hydroxyphenyl)3.6-endomethylene-1,2,3,6-tetrahydro Phthalimide.

N-(m-hydroxyphenyl)methylendomethylenetetrahydrophthalimide, N-(p-hydroxyphenyl)methylendomethylenetetrahydrophthalimide, N-(m-hydroxyphenyl)tetrahydrophthalimide, N-(p-hydroxyphenyl)tetrahydrophthalimide, N-(m-hydroxyphenyl)4-methyl-1,2,
3,6-tetrahydrophthalimide.

N-(p-hydroxyphenyl)4-methyl-12,3
, 6-tetrahydrophthalimide, N-(2-hydroxyethyl)maleimide, N-(2-hydroxyethyl)
3.6-endomethylene-1,2,3,6-tetrahydrophthalimide, N-(2-hydroxyethyl)methylendomethylenetetrahydrophthalimide, N-2-hydroxyethyl)tetrahydrophthalimide or N-(2-hydroxyethyl) )4-methyl-1,2,3
, 6-tetrahydrophthalimide, etc. are used.

Further, as the aromatic dicarboxylic acid dihalide that can be used in the present invention, dichlorides of aromatic dibasic acids are convenient, and representative examples include terephthalic acid dichloride, isophthalic acid dichloride, phthalic acid dichloride, and mixtures thereof.

The aromatic polyamide derived from phthalic acid dichloride has slightly insufficient heat resistance, and when using terephthalic acid dichloride, although the heat resistance of the polymer after heat curing is sufficient, the aromatic polyamide obtained as a precursor Polyamide group polyamide oligomers tend to have high melting points and become difficult to handle. From a practical standpoint, isophthalic acid dichloride has the most well-balanced properties and meets the purpose of the present invention.

Since this synthesis reaction proceeds relatively stoichiometrically, the necessary amount of cyclic unsaturated imide, aromatic diamine and aromatic dicarboxylic acid is It is sufficient to react the dihalide, and if precise adjustment is required, the molar ratio can be determined by a simple test.

As already explained, the composition of the aromatic polyamide onogomer obtained by this reaction can be easily selected, and it can be easily molded at a temperature of 200° C. or lower.

The aromatic polyamide oligomer having a cyclic unsaturated group at the end synthesized according to the present invention can be cured in combination with a radical generating catalyst, making it possible to significantly improve heat resistance.

There is no need to limit the radical generating catalyst, but peroxide type is suitable industrially, and the molding temperature is 1.
When the temperature is 00° C. or higher, a so-called high-temperature decomposition type, for example a dicumyl peroxide type, is used.

The appropriate amount to use is 1 to 3 phr.

Further, the combined use of a monomer copolymerizable with the unsaturated bond of the oligomer of the present invention is possible when the monomer dissolves the aromatic polyamide oligomer, and this is particularly possible when n in the formula [A] above is a small value. The combined use of monomers, which have a wide range of applications, promotes the softening of the entire condensation system and improves moldability and workability, but tends to reduce the heat resistance of the cured aromatic polyamide. It is necessary to adjust the amount of addition.

When manufacturing a molded article using the aromatic polyamide oligomer having an unsaturated group according to the present invention, reinforcing agents, fillers, mold release agents, coloring agents, other polymers as low shrinkage agents, etc. can be used in combination as necessary. Of course.

Next, examples will be shown below to help understand the present invention.

space below) [Example] (Example I)) 500 equipped with a reflux condenser, dropping funnel, thermometer, and stirrer
20.3 g (0.1 mol) of isophthalic acid chloride and 100 g of dimethylformamide (DMF) are placed in a ml2 four-necked separable flask and cooled to 10° C. or lower.

Next, N-(p-hydroxyphenyl)maleimide 6.3
g (0,0333 mol), 3.4'-diaminodiphenyl ether (3,4'-DAPE) 16°67 g
(0,0834 mol), triethylamine 20.5 g
(0,203 mol), weigh 80 g of DMF! mix,
Add dropwise to reaction flask. During this time, the reaction temperature is kept below 10°C.

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

Further, stirring is continued for 2 hours while maintaining the temperature of the reaction mixture at 10° C. or lower.

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

m, p, 180-200''C1 The infrared absorption spectrum of this product is shown in FIG.

Elemental analysis values are: C, 71,38%: H, 3,97%: N, 7.6
The theoretical value at 2% is: C1 71.18%: Hl 3°99%: N.

7.78% showed good agreement.

(Example 2) The same operation as in Example 1 was performed except that 6.3 g (0,0333 mol) of N-(m-hydroxyphenyl)maleimide was used instead of 1 1 -(p-hydroxyphenyl)maleimide.

m, p, 185-200°C, the infrared absorption spectrum of this product is shown in Figure 2.

What is the elemental analysis value?

C, 71,35%: H, 3,95%: N, 7.5
The theoretical value is 9%.

C171, 18%; H, 3-99%: N, 7.78
% showed good agreement.

(Example 3) N-(p-hydroxyphenyl)3.6-endomethylene-1,2,3,6-tetrahydrophthalimide 8.5 instead of N-(p-hydroxyphenyl)maleimide
The same operation as in Example 1 was carried out except that g (0,0333 mol) was used.

m, p, 175-190°C, and the infrared absorption spectrum of this product is shown in FIG.

What is the elemental analysis value?

C, 72,49%: H, 4,31%: N 7.16% The theoretical values are: C, 72,31%: H, 4,28%, N, 7.34%
showed good agreement.

(Left below) (Example 4) 8.97 g of N-(p-hydroxyphenyl)methylendomethylenetetrahydrophthalimide instead of N-(p-hydroxyphenyl)maleimide (0,0333
The same operation as in Example 1 was performed except that mol) was used.

m, p, 160-180°C, and the infrared absorption spectrum of this product is shown in FIG.

Elemental analysis values are: C, 72,65%: H, 4,31%, N, 7.21%
The theoretical values are: C, 72,4δ%: H, 4,40%, N, 7.2
Good agreement was shown at 5%.

(Example 5) The same operation as in Example 1 was carried out except that 8.1 g (0,0333 mol) of N-(p-hydroxyphenyl)tetrahydrocttalimide was used instead of N-(p-hydroxyphenyl)maleimide. Ta.

m, p, 155-170°C, and the infrared absorption spectrum of this product is shown in FIG.

The elemental analysis values are: C, 72,23%, H, 4,29% + N, 7.24%, and the theoretical values are: C, 72,02%; H, 4,32%: N, 7.41
% showed good agreement.

(Example 6) 6.3 g of N-(m-hydroxyphenyl)maleimide instead of N-(p-hydroxyphenyl)maleimide
(0,0333 mol), 6 m, the same operation as in Example 1 was performed except that 20.67 g (00,833 mol) of 3,3'diaminodiphenyl sulfone was used instead of 3,4'diaminodiphenyl ether, P, 155-170°C, the infrared absorption spectrum of the horn is shown in FIG.

Elemental analysis values: C, 63,97%, H, 3,53%: N, 6.8
The theoretical value at 5% is: C, 64,05%: F(, 3,59%: N, 7.
It showed a good agreement of 0.01%.

[Effect of the invention J Conventional aromatic polyamide is a thermoplastic resin,
Despite having excellent properties such as chemical resistance and electrical properties due to its high melting point, it has difficulties in moldability, and its mechanical strength at high temperatures decreases significantly, so it is below the melting point or decomposition point. Even at a temperature of The present invention improves these drawbacks and creates a new unsaturated polyamide that can be used as a raw material for thermosetting aromatic polyamides that have excellent moldability and exhibit little decrease in mechanical strength even at high temperatures. We have succeeded in developing aromatic polyamide oligomers containing groups.

This oligomer can be synthesized at low temperatures, and although it has polymerizable double bonds, it is relatively stable and does not gel during the molding process, and because of the action of a radical-generating catalyst, it can be easily synthesized even at low temperatures. It has excellent properties that allow it to be hardened.

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

[Brief explanation of the drawing]

FIGS. 1 to 6 are infrared absorption spectra of aromatic polyamide oligomers having a cyclic unsaturated group at the end obtained in Examples 1 to 6, respectively.

Claims (4)

[Claims] (1) General formula ▲ There are mathematical formulas, chemical formulas, tables, etc. ▼ However, in the formula, R_1 and R_2 are divalent aromatic groups, R_3 is a divalent aliphatic group or aromatic group, and A and B are aliphatic It represents an unsaturated group (A=B is also acceptable), and n is any numerical value from 1 to 15. An aromatic polyamide oligomer having a cyclic unsaturated group at the terminal represented by: (2) In claim 1, the aromatic polyamide oligomer has a cyclic unsaturated group at its terminal, where the aliphatic unsaturated group is ▲a numerical formula, a chemical formula, a table, etc.▼. (3) characterized by reacting aromatic diamine, aromatic dicarboxylic acid dihalide, N-(hydroxyphenyl) cyclic unsaturated imide or N-(hydroxyalkyl) cyclic unsaturated imide in the presence of a hydrogen halide acceptor; A method for producing an aromatic polyamide oligomer having a cyclic unsaturated group at the terminal thereof. (4) As the N-(hydroxyphenyl) unsaturated imide in claim 3, N-(m-hydroxyphenyl)maleimide, N-(p
-hydroxyphenyl)maleimide, N-(m-hydroxyphenyl)3,6-endomethylene-1,2,3,
6-tetrahydrophthalimide, N-(p-hydroxyphenyl)3,6-endomethylene-1,2,3,6-tetrahydrophthalimide, N-(m-hydroxyphenyl)methylendomethylenetetrahydrophthalimide, N-(p- hydroxyphenyl)methylendomethylenetetrahydrophthalimide, N-(m-hydroxyphenyl)tetrahydrophthalimide, N-(p-hydroxyphenyl)tetrahydrophthalimide, N-(m-hydroxyphenyl)4-methyl-1,2,
A method for producing an aromatic polyamide oligomer having a cyclic unsaturated group at the terminal using 3,6-tetrahydrophthalimide or N-(p-hydroxyphenyl)4-methyl-1,2,3,6-tetrahydrophthalimide.