JPH0457697B2 - - Google Patents

Description

[Detailed description of the invention]

(Industrial Application Field) The present invention relates to an aromatic heterocyclic polyamideimide having excellent heat resistance. (Prior Art) Polyamideimide is known as a plastic with excellent heat resistance and high mechanical strength.
Polyamide-imide can be molded into complex and precise parts by methods such as compression molding, extrusion molding, and injection molding, but because it is an organic polymer, it does not necessarily have sufficient heat resistance. Among organic polymers, poly-p-phenylenebenzobisthiazole (PBT) has the highest heat resistance and is attracting attention as a high-strength, high-modulus resin. Because PBT is infusible, it cannot be molded into mechanical parts, and fiber ribbons are only obtained from strong acid solutions such as methanesulfonic acid and polyphosphoric acid. (Problems to be Solved by the Invention) As a result of intensive studies to develop a high-performance resin that has the heat resistance of PBT and the moldability of polyamide-imide, the present inventor discovered that polyamide containing a benzobistiazole ring We have discovered that imide is an excellent new substance, and have arrived at the present invention. (Means for solving the problems) That is, the object of the present invention is to solve the following general formula The structural unit represented by 50 mol% of the total polymer
The gist of the present invention is to produce an aromatic heterocyclic polyamideimide containing the above, and the gist of the present invention is to react a diamine and anhydrous trimellitic acid chloride in a polar organic solvent in the presence of an acid absorber, and further heat Or, in a method for producing an aromatic heterocyclic polyamide-imide by ring-closing the imide with a ring-closing agent,
The present invention provides a method for producing an aromatic heterocyclic polyamide-imide, characterized in that the diamine mainly consists of a benzobistiazole ring-containing diamine represented by the following structural formula (). The above benzobistiazole ring-containing diamine is
2,5-diamino-1,4-benzenedithiol dihydrochloride and p-aminobenzoic acid, m-aminobenzoic acid, o-aminobenzoic acid, p-aminobenzonitrile, m-aminobenzonitrile, o-amino One or more aromatic aminocarboxylic acid derivatives such as benzonitrile, etc. in polyphosphoric acid.
It is obtained by stirring and reacting at a high temperature of 160 to 200°C, then pouring it into a large amount of water, and purifying the precipitated cake. In the synthesis of aromatic heterocyclic polyamideimide, less than 50 mol% of the diamine component may be a diamine that does not contain the benzobisthiazole ring. Such diamines include diaminodiphenyl ether, diaminodiphenylmethane, thiodianiline, diaminodiphenylsulfone, diaminobenzophenone,
Examples include aromatic diamines such as phenylenediamine. In addition, for the purpose of modifying the aromatic heterocyclic polyamideimide, a part of the trimellitic anhydride is added to an aromatic tetracarboxylic acid such as pyromellitic anhydride, biphenyltetracarboxylic anhydride, benzophenonetetracarboxylic anhydride, etc. May be replaced with anhydrous. Furthermore, for the purpose of imparting reactivity,
About 0.1 to 3 mol% of an ethynyl compound such as 3-aminophenyl acetylene may be reacted. Preferred examples of the deoxidizing agent include lithium carbonate, triethylamine, pyridine, and α-picoline. Preferred polar organic solvents are dimethylformamide, dimethylacetamide, N-methyl-2-pyrrolidone, hexamethyl-phosphorotriamide, and 1,3-dimethyl-2-imidazolidinone. Particularly preferred are N-methyl-2-pyrrolidone, 1,3-
Dimethyl-2-imidazolidinone is used.
The reaction temperature is selected from -25°C to +80°C. The obtained amic acid is purified, dried, and then heated to a high temperature to perform an imide ring-closing reaction, or treated in a mixed solvent of acetic anhydride and pyridine at a 3:1 molar ratio for 1 hour.
An aromatic heterocyclic polyamide-imide can be obtained by any of the methods of purification and drying after treatment for 24 hours. Dry polyamideimide can be made into a molded product by preforming and curing. (Example) The gist of the present invention will be explained below with reference to Examples. Example 1 4.629 g (0.0124 mol) of 2,6-bis(4-aminophenyl)benzobisthiazole was dissolved in 60 ml of N-methyl-2-pyrrolidone with 2 ml of triethylamine, and 2.52 g (0.012 mol) of trimellitic anhydride chloride was dissolved with stirring. mol) was added and the reaction was continued for 12 hours. While the resulting polymer solution was immersed in an ice bath, 20 ml of pyridine and 60 ml of acetic anhydride were added thereto and reacted for 3 hours, and then at 60° C. for 1 hour. After the reaction was completed, the mixture was washed with a large amount of water and dried under vacuum to obtain 6.4 g of reddish-brown polymer (A). The thermal decomposition temperature of this polymer (A) was 542°C at a residual weight of 95%. Further, when this polymer (A) was hot pressed at 380°C for 1 hour, a pressed piece with toughness was obtained. Comparative Example Polymer (B) obtained in the same manner as in Example 1 using 4,4'-diaminodiphenyl ether as the diamine had a thermal decomposition temperature of 445°C. (Effects of the Invention) According to the present invention, a heat-resistant polyamide-imide that can be easily molded can be obtained.

[Claims]

1 General formula () (In the formula, m indicates the number of repetitions) and has a logarithmic viscosity of 3 to 15 dl/g (in methanesulfonic acid solvent, concentration 0.25 g/dl, temperature 30°C
(measured by) and the general formula () A method for producing an aromatic heterocyclic block copolymer, which comprises reacting a monomer represented by the following in polyphosphoric acid.

Claims (1)

A method for producing an aromatic heterocyclic polyamide-imide, wherein the diamine mainly consists of a benzobistiazole ring-containing diamine represented by the following structural formula ().