JPS6369827A - Production of polymaleimide - Google Patents

Abstract

PURPOSE:To obtain a polymaleimide having high purity, in high efficiency, by producing a polymaleamic acid in an organic solvent and subjecting the acid to dehydrative cyclization in the presence of a dehydration agent, a metal salt and a tert-amine while distilling the organic solvent out of the system. CONSTITUTION:A polymaleimide can be produced by (1) producing a polymaleamic acid (A) from (i) a polyamine having >=2 amino groups in the molecule (e.g. 4,4'-diaminodiphenylmethane) and (ii) maleic anhydride in an organic solvent (e.g. acetone) and (2) subjecting the acid A to dehydrative cyclization in the presence of (B) a dehydration agent (e.g. acetic anhydride), (C) a metal salt (e.g. nickel acetate) and (D) a tert-amine (e.g. triethylamine) while distilling the solvent out of the system. The amounts of the components B, C and D are preferably 1-1.5mol, 0.001-0.1mol and 0.05-0.5mol per 1 equivalent of the amino group of the polyamine, respectively.

Description

[Detailed description of the invention] <Industrial application field> The present invention relates to a method for efficiently producing high-purity polymerimide. <Prior art> Polymaleimide contains two or more maleimide groups in the molecule. A compound that causes a polymerization reaction alone or in combination with other monomers to form a cured thermosetting resin. This cured product has excellent heat resistance, so it can be used for casting, impregnation, etc.
It is used as a material for lamination and molding, various electrical insulation materials, structural materials, etc.

Traditionally, the most common method for producing polymaleimide is
After polymaleamide acid is produced from polyamine and maleic anhydride in an organic g medium, it is dehydrated and cyclized in the presence of a dehydrating agent, a metal salt, and an 8th class amine, and then water or an organic precipitant is added to form the polyimide. Methods for separating by precipitation are known (e.g., Japanese Patent Application Laid-Open No. 18285/1985) (Problems to be Solved by the Invention) However, the conventionally known method for separating polymaleimide does not require much volume due to the addition of a precipitant. It requires a large pot and is not efficient, and it is difficult to recover and recycle the reaction solvent from the p-liquid.

¥, 6 kayo. Eh, 3. Good morning. , , □ (There were problems such as a decrease in purity because impurities that had been dissolved were precipitated together.

<Means for Solving the Problems> Against this background, the present inventors have conducted intensive studies on methods for efficiently producing high-purity polymaleimide, and have discovered that a specific method is suitable for the above-mentioned purpose. The present invention has been completed.Accordingly, the present invention relates to a method for producing cypolymaleimide by the reaction of a polyamine having two or more amino groups in the molecule with maleic anhydride. A method for producing a polymaleimide, which is characterized in that after generating an acid, dehydration and cyclization is carried out while distilling off an organic solvent in the presence of a dehydrating agent, a metal salt, and an 8th-class amine. Examples of polyamines having two or more 7-mino groups in the molecule include diaminodiphenylmethane, phenylenediamine, tolylenediamine, xylylenediamine, diaminodiphenyl ether, diaminodiphenylsulfone, and 2,2-bis(aminophenyl)propane (respectively). (including isomers), ethylene diamine, hexamethylene diamine, and polycondensates of aniline and foam μdehyde, among which 4°4'-diaminodiphenylmethane is particularly preferred.

Examples of organic solvents used in the present invention include ketones such as acetone, methi-μ-ethyketone, methyl isobutyl ketone, V-chlorohexanone, and acetophenone, NlN-dimethylformamide, N,N-dimethylacetamide, dimethylsulfoxide, N -methy/l/-2-pyrrolidone,
Aprotic polar solvents such as acetonitrile and sulfofane, cyclic ethers such as dioxane and ketone hydrofuran, esters such as ethyl acetate and butyl acetate, chlorobenzene, dichlorobenzene, chloroform, carbon tetrachloride,
Examples include halogenated solvents such as dichloroethane and trichloroethane, and acetone is particularly preferred.

In the method of the present invention, the polymaleamic acid production reaction is
Conventionally known methods can be applied. For example, polyamine and maleic anhydride are mixed in a proportion of 1.
Used in a quantitative ratio of 0 to 1.5, in an organic solvent at a weight ratio of 1 to 60 relative to the total amount of polyamine and maleic anhydride, at a temperature of 10 to 100°C, preferably 20 to 50°C. can be done.

Dehydrating agents used in the present invention include lower aliphatic acid anhydrides such as acetic anhydride, propionic anhydride, and butyric anhydride; oxides such as phosphorus pentoxide, calcium oxide, and barium oxide; Examples include sulfonic acids such as /enesulfonic acid and methanesulfonic acid, and inorganic acids such as sulfuric acid, but acetic anhydride is particularly preferred.Metal salts used in the present invention include nickel, cobalt, etc.
Examples include acetates, chlorides, bromides, sulfates, and nitrates of sodium, sodium, Vt/Vt/lamb lithium, manganese, etc., and nickel acetate is particularly preferably used.

Examples of tertiary amines that can be used in the present invention include triethylamine, tri-n-butylamine, N-methymupibefudine, N,N-dimethymobenzylamine, and 1,8-diazabicyclo(5,4,0)7-undecene. For example, triethylamine is particularly preferred.0 The amounts of the dehydrating agent, metal salt, and 8th-class amine used in the dehydration cyclization reaction of the method of the present invention are subject to special VC restrictions #'i
However, the dehydrating agent is usually 1 to 8 mol, preferably 1 to 1.5 mol, and the metal salt is 0.0001 to 1.01, preferably o, o o i to 1 mole, per 1 amino group of the polyamine.
0.1 mol, and the 8th class amine is 0.01 to 1.0 mol, preferably 0.05 to 0.57 mol. In the present invention, the dehydration cyclization reaction was used in the polymaleamic acid production reaction. Organic solvent at 20-100°C, preferably 80-80°C
The main feature is that the reaction is carried out while being distilled off under the temperature conditions of
In this case, the reaction can be slowed down to some extent by holding the temperature at the same temperature before distilling off the organic solvent ◎ After distilling off the reaction solvent and confirming the completion of the cyclization reaction, cool to below 10°C as necessary. High purity polymerimide can be obtained by filtering and filtering. <Effects of the invention> According to the method of the present invention, high purity polymaleimide can be efficiently obtained without adding a precipitant. 〇〉〉〉〉〉〉〉〉〉〉〉〉〉〉〉〉〉〉〉〉〉〉〉〉〉〉〉〉〉〉〉〉〉〉〉〉〉〉〉〉〉〉〉〉〉〉〉〉〉〉〉〉〉〉〉〉〉〉〉〉〉〉〉〉〉〉〉〉〉〉〉〉〉〉〉〉〉〉〉〉〉〉〉〉〉〉〉〉〉〉〉〉〉〉〉〉〉〉〉〉 A solution of 0-order K 4.4'-diaminodiphenylmethane (manufactured by Sumitomo Chemical Co., Ltd.) 99F (0.5 mo!v) in which maleic anhydride was dissolved and acetone 252F dissolved in acetone 281F was prepared at room temperature. The mixture was added dropwise into the reactor, which was being stirred at ℃ for 4 hours. After the addition was completed, stirred at the same temperature for 2 hours, and added triethylamine 7,6F.
(0,075 mo/L/) and nickel acetate/I/4 hydrate 1.06F (4.25 mm7μ) were added, and while stirring, acetic anhydride 182.6F (1.8 mo/L/) was added. ) to 5
After dropping 90 drops over 1 hour at 6°C, the mixture was kept at the same temperature for 2 hours, and the acetone was distilled off over about 8 hours under reduced pressure while keeping the same temperature, resulting in a reaction rate of about 100%. After distilling off the acetone that had reached 0.0°C, the crystals were cooled to 10°C and held at the same temperature for 1 hour, and the crystals were separated by F, washed with water, and dried to obtain j9, GPC purity of 96%, melting point of 168-162°C. N, d-4,4-diaminodiphenylmethane bismaleimide was obtained as a pale yellow solid.90 Example 2 The procedure of Example 1 was repeated except that the acetone distillation temperature was 40°C and the distillation time was 5 hours. As a result, GP
Bismaleimide with a C purity of 97% and a melting point of 159-162°C was obtained.

Comparative Example 1 After carrying out the same operation as in Example 1 up to the dropwise addition of acetic anhydride, the acetone was held at 56°C for 7 hours without distilling off, and it was confirmed that the reaction rate reached approximately 100*. from,
The reaction solution was transferred to a double volume reactor, and IJ water was added to precipitate the product, washed with water and dried to obtain bismaleimide as a brown solid with a υGPC purity of 86 or better and a melting point of 155-167°C.

Comparative Example 2 After performing the same operation as in Comparative Example 1 until a reaction rate of 100% was confirmed, acetone was distilled off at a temperature of 55 to 58°C, then cooled to 10°C, and held at the same temperature for 1 hour. After that, separate the crystals, wash them with water, and dry them.
Bismaleimito was obtained as a yellow solid with a C purity of 92% and a melting point of 167-160°C.

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Claims (1)

[Claims] In a method for producing polymaleimide by reacting a polyamine having two or more amino groups in the molecule with maleic anhydride, polymaleamic acid is produced in an organic solvent, and then a dehydrating agent, a metal salt, and a 8th-class amine are added. A method for producing polymaleimide, which comprises carrying out dehydration and cyclization while distilling off an organic solvent in the presence of polymaleimide.