JPS6017376B2 - Manufacturing method of polyamide resin - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention particularly relates to a method for producing a polyamide resin having excellent heat resistance and solubility.

More specifically, the present invention relates to a method for producing a polyamide resin having a quinazolone ring in the polymer primary mirror. Aromatic polyamides, polyamideimides, and the like are conventionally known as heat-resistant polyamides.

The former is a polyamide with a structure obtained by polycondensing a monomer having a carboxyl group directly bonded to an aromatic ring and an amine/group, and its polymerization method uses a dehydrochlorination reaction in which a diacid halide and a diamine are polymerized at low temperature. It is being done. but,
This reaction progresses very rapidly and is usually completed within a few minutes, so that side reactions are likely to occur, so advanced techniques are required for quality control. On the other hand, the latter polyamideimide is first made into an intermediate having a polyamidecarboxylic acid structure by reacting diamines with pyromellitic anhydride (or its acid chloride), and then converted into polyamideimide by heating or chemical treatment. A method of converting is performed. However, in this method, the amic acid solution is unstable, and has disadvantages such as a decrease in viscosity during solution storage and insolubilization due to imide cyclization.

There is also a method using imidocarboxylic acid obtained by reacting diamines and trimellitic anhydride as a starting material, but in this case, it follows the same route as the former and has the same disadvantages as the former. has. The feature of the present invention is to provide a stable polyamide, which also has heat resistance,
Because it has a quinazolone ring with excellent solubility, it is characterized by providing polyamide with excellent thermal stability.

That is, the present invention is based on the following general formula (1) (in the formula ~ or or (the same applies below), R is C Koichi or shows.

) A bismethylol compound containing two quinazolone rings in one molecule represented by the general formula (b) NC-R'-CN (0) (wherein R' is selected from -(CH2)4- and Indicates a divalent organic group.

) The present invention relates to a method for producing a polyamide resin obtained by carrying out an addition reaction with a dinitrile compound represented by the following.

The polyamide resin obtained by the method of the present invention is soluble in commonly known solvents such as m-cresol, NN-dimethylacetamide, NN-dimethylformamide, and N-methyl-2-pyrrolidone, and heat-resistant and tough resins can be obtained from these solutions. You can get the film. The bismethylol compound represented by the general formula (1) used in the present invention can be easily obtained, for example, by the method shown below.

That is, a diami/dicarponic acid compound having two sets of an ami/group and a carpoxyl group in one molecule that are bonded to each other at the ortho position of an aromatic nucleus, such as diaminoterephthalic acid or methylenebisanthranilic acid, and acetic anhydride; Alternatively, bisquinazolone of the following general formula (m) obtained by reacting general formula (0) with ammonia using a pisoxazinone shown by the following general formula m) obtained by reaction with penzoyl chloride etc. as a starting material,
NN dimethylformamide, NN dimethylacetamide or N methyl 2-pyrrolidone in an amount to give a 10-15% solution and heat to 130-150°C.

Next, 38% formalin solution containing, for example, 2.1 moles of formaldehyde of general formula (m) is added to this system, and the reaction is carried out under reflux for 1 to 2 hours. During this time, as the reaction progresses, a homogeneous solution is formed. Further, a 38% formalin solution containing 1.0 times the molar amount of formaldehyde of general formula (m) is added, and reflux is performed. The reaction solution is poured into water to obtain a filtrate, which is then filtered to obtain a bismethylol compound represented by the general formula (1). Thereafter, by recrystallizing with, for example, dioxane-NN dimethylform, a bismethylol compound with even higher purity can be obtained. Dinitrile compounds used in the present invention include adiponitrile, isophthalonitrile, and terephthalonitrile. The method of the present invention can be carried out electrophilically by using the bismethylol compound of general formula (1) obtained as described above and the dinitrile compound described above in an acidic solvent.

That is, equimolar amounts of a bismethylol compound and a dinitrile compound are mixed in an acidic solvent such as sulfuric acid, acetic acid, formic acid, polyphosphoric acid, or a mixed solvent thereof at 0 to 50°C for 2 to 1
A viscous resin solution can be obtained by performing a time reaction. This solution is poured into water and precipitated to separate the polyamide resin. This resin is m-cresol, N
It is soluble in polar solvents such as N dimethylacetamide, and has an intrinsic viscosity of usually 0.2 to 1.2 degrees. As described above, according to the method of the present invention, 0 to 50°C, 2 to 1
An amide bond can be generated through a gentle reaction known as insect time, and the desired polyamide resin can be obtained without side reactions.

The resulting resin contains quinazolone rings, so it has good heat resistance and
It has excellent solubility and can be used for various purposes such as electrical insulating materials, such as dissolving it in an appropriate solvent and using it as a moat-containing varnish, or mixing it with other resins such as epoxy resin and using it for casting. . At that time, fillers such as alumina and other coloring agents may be used together. The present invention will be specifically explained below with reference to Examples.

The structural formulas and abbreviations of the bismethylol compounds used in the examples are shown below.

Example 1 The above NQ-1 3 was placed in a flask equipped with a concentrator and a thermometer.
．． Add 0.2 mol (0.01 mol) and concentrated sulfuric acid 16 mol, and add 25 mol.
``Melt it evenly in a water bath of 0.

1.08 of adiponitrile while keeping the liquid temperature at 25qo.
Add hydroxide (0.01 mol) and react for 8 hours. The reaction solution is pale yellow in color. Pour the reaction solution into finely crushed ice water to obtain a white precipitate.
The white precipitate was filtered and mixed with dilute aqueous sodium carbonate solution, water,
Wash with acetone and dry under reduced pressure to obtain a polymer.
This polymer was soluble in m-cresol and NN dimethylacetamide, and had an intrinsic viscosity of 0.60 (measured in NN dimethylacetamide at 30°C).

In the analysis of the infrared absorption spectrum of this polymer, 1680
Characteristic absorption of the quinazolone ring appears at arc-1 and 1618-1, absorption based on the amide bond appears at 1650 arc-1 and 1520 skin-1, and a decrease in absorption due to the methylol group near 3400 is observed. The formation of quinazolone ring-containing polyamide was confirmed. Example 2 3.92 MQ-2 in a flask equipped with a thermometer and a thermometer
(0.01 mol), 20 mol of formic acid, and 2 mol of concentrated sulfuric acid,
Dissolve homogeneously in a 25 qo water bath.

1.28 molar (0.01 mol) of isophthalonitrile is added to this system and reacted for 5 hours. The reaction solution is viscous and has a pale yellow color. A baller was obtained using the same treatment method as in Example 1. The intrinsic viscosity of this polymer is 0.68 (NN
dimethylacetamide (measured at 30°C). Generation of a quinazolone ring-containing polyamide was confirmed by infrared absorption spectrum analysis in the same manner as in Example 1. Example
3. 5.1 of MQ-3 in a flask equipped with a thermometer and a thermometer.
6 (0.01 mol) and 1.2 of terephthalonitrile
Add 8 Ushio (0.01 mol) and 25 mol of polyphosphoric acid, and make 50
React at 1°C for 1 hour.

The reaction solution was treated in the same manner as in Example 1 to obtain a polymer. The intrinsic viscosity of this polymer was 0.26. (NN
Dimethylacetamide (measured at 30°C) In the same manner as in Example 1, the formation of a quinazolone ring-containing polyamide was confirmed by infrared absorption spectrum analysis. Example 4 The polymer obtained in Example 1 was dissolved in NN dimethylacetamide, applied to an aluminum plate, and heated to remove the solvent to obtain a yellow colored film.

The Tg of this film was found to be around 140 qo. In addition, in thermogravimetric analysis, in air (heating rate of 1ooo/min)
Initial decomposition occurred at 320qo, and the weight loss rate at 400qo was 10%. Example 5 The polymer obtained in Example 2 was treated in the same manner as in Example 4 to obtain a film.

This film showed no apparent Tg. Thermogravimetric analysis shows that in air (heating rate of 10°C/min) 38
Initial decomposition occurred at 0°C and a 10% weight loss occurred at 44,000°C. As described above, according to the method of the present invention, the reaction temperature may be low, and the resulting polyamide resin has remarkable heat resistance, which is extremely advantageous industrially.

Claims (1)

[Claims] 1 General formula ▲ There are mathematical formulas, chemical formulas, tables, etc. ▼ (In the formula, Ar indicates ▲ There are mathematical formulas, chemical formulas, tables, etc. ▼ or ▲ There are mathematical formulas, chemical formulas, tables, etc. ▼ A bismethylol compound containing two quinazolone rings in one molecule represented by CH_3- or ▲There are mathematical formulas, chemical formulas, tables, etc.) and the general formula (II) NC-R'-CN (II) ( In the formula, R' represents a divalent organic group selected from -(CH_2)_4- and ▲There are mathematical formulas, chemical formulas, tables, etc.). Method for producing polyamide resin. 2. The method for producing a polyamide resin according to claim 1, wherein the reaction is carried out in an acidic solvent.