JPH0514725B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a novel polymaleimide having excellent heat resistance and a method for producing the same. The polymaleimide of the present invention can be dissolved in general-purpose solvents such as acetone, methyl ethyl ketone, tetrahydrofuran, and chloroform, and is useful as a resin for prepregs. Resins with imide groups exhibit excellent electrical insulation, heat resistance, and dimensional stability of molded products.
Widely used in industry. For example, polyimide resins and polymaleimide resins are known as heat-resistant resins used for electrical insulation materials.
Although polyimide resin has excellent heat resistance, it is difficult to mold because it is insoluble and infusible. Polymaleimide, represented by N,N'-4,4'-diphenylmethane bismaleimide, has high thermal stability, but has a slow curing speed and requires long-term heating at high temperatures to fully cure. There is a problem with this. Furthermore, since this polymaleimide is poorly soluble in low-boiling point solvents, it must be dissolved in special high-boiling point solvents such as dimethylformamide and N-methylpyrrolidone. After impregnation, high temperatures are required to volatilize the solvent, and it is difficult to completely remove the solvent from the laminate, which has the disadvantage of degrading the quality of the product. The present invention has been made to improve the drawbacks of these polymaleimides. , general expression (), [In the formula, X is a hydrogen atom, a halogen atom, or an alkyl group or an alkoxy group having 1 to 4 carbon atoms.] A polyamine is obtained by reacting an aromatic amine represented by the following in a proportion of 0.5 to 60 moles, and then the polyamine is and an acid anhydride to obtain a polyamic acid, and then the polyamic acid is dehydrated and cyclized. In the practice of the present invention, the aromatic monoaldehyde having at least one phenolic hydroxyl group in one molecule used in the production of polyamine has the general formula () [In the formula, Y represents a hydrogen atom, a halogen atom, or an alkyl group or alkoxy group having 1 to 4 carbon atoms, and m and p are integers of 1 or 2.] Compounds represented by the following, specifically o-hydroxy Examples include benzaldehyde, m-hydroxybenzaldehyde, p-hydroxybenzaldehyde, vanillin, syringaldehyde, β-resorcylaldehyde, protocatechyaldehyde, and the like. Further, aromatic amines include aniline, o-toluidine, m-toluidine, p-toluidine, o-toluidine,
-ethylaniline, o-isopropylaniline,
Examples include p-butylaniline, o-anisidine, m-anisidine, p-anisidine, o-phenetidine, chloranilines, and bromoanilines. The reaction between aromatic monoaldehyde and aromatic amine is carried out in the presence of an acidic catalyst such as mineral acids such as hydrochloric acid and sulfuric acid, organic acids such as oxalic acid and p-toluenesulfonic acid, and other organic acid salts. 0.5 to 60 moles of aromatic amine per mole of aldehyde,
The condensation reaction is preferably carried out in a proportion of 1 to 30 moles at a temperature of 40 to 150°C for 1 to 10 hours. After the reaction is completed, the reaction mixture is neutralized using an alkali such as sodium hydroxide, washed with water, and then excess aromatic amine is removed under reduced pressure to obtain a polyamine. The obtained polyamine is solid at room temperature (20° C.) and has a structure represented by the following formula (). [In the formula, X and Y represent a hydrogen atom, a halogen atom, or an alkyl group or alkoxy group having 1 to 4 carbon atoms. n represents an integer from 0 to 10,
m and p are integers of 1 or 2]. General formula () for 1 equivalent of amino group of this polyamine [In the formula, D represents a divalent organic group having 2 to 30 carbon atoms and having a carbon-carbon double bond.] 0.9 to 1.2 moles of the acid anhydride represented by the formula are dissolved in a suitable organic solvent, and 0 to 1.2 moles of the acid anhydride represented by Perform the addition reaction at 40℃ for 0.5 to 4 hours to obtain the general formula () [In the formula, X and Y represent a hydrogen atom, a halogen atom, or an alkyl group or alkoxy group having 1 to 4 carbon atoms. D represents a divalent organic group having 2 to 30 carbon atoms and having a carbon-carbon double bond. n is 0
Represents an integer greater than or equal to 10 and less than or equal to 10, where m and p are 1 or 2
is an integer of ] to obtain a polyamic acid represented by Specific examples of the acid anhydride represented by the general formula () include maleic anhydride, citraconic anhydride, itaconic anhydride, pyrosinconic anhydride, 3-chloromaleic anhydride, 3,4-dichloromaleic anhydride,
Examples include dodecenylsuccinic anhydride, chlorendic anhydride, 5-norbornene-2,3-dicarboxylic anhydride, tetrahydrophthalic anhydride, methyltetrahydrophthalic anhydride, and methylnadic anhydride. Next, in the method for producing polymaleimide by allowing a dehydrating agent to act on the polyamic acid represented by the general formula (), the reaction in which the dehydrating agent is applied is the third step.
The reaction is carried out in an organic solvent in the presence of a class amine and a catalyst, or the reaction is carried out in an organic solvent with a dehydrating agent, and after the reaction is completed, a precipitate is precipitated using a precipitating agent such as water, and the precipitate is separated and purified. By the general formula () [In the formula, X and Y represent a hydrogen atom, a halogen atom, or an alkyl group or alkoxy group having 1 to 4 carbon atoms. D represents a divalent organic group having 2 to 30 carbon atoms and having a carbon-carbon double bond. n is 0
Represents an integer greater than or equal to 10 and less than or equal to 10, where m and p are 1 or 2
is an integer of ] is obtained. The dehydrating agent used in the method of the present invention is a compound that acts on the production of polymaleimide through the cyclodehydration reaction of polyamic acid, and includes lower carboxylic anhydrides such as acetic anhydride, propionic anhydride, and butyric anhydride; succinic anhydride; , dicarboxylic acid anhydrides such as glutaric anhydride, phthalic anhydride, and benzoic anhydride; inorganic salts such as sodium sulfate, magnesium sulfate, and calcium sulfate; oxides such as calcium oxide and barium oxide; sulfur trioxide, sulfur sesquioxide, Sulfur oxides or sulfur oxygen acids such as sulfuric acid and perdisulfide; oxidation of phosphorus such as phosphorus sesquioxide, multiple phosphorus dioxide, phosphorus pentoxide, phosphorus trioxide, orthophosphoric acid, metaphosphoric acid, pyrophosphoric acid, tripolyphosphoric acid, etc. Condensed phosphoric acid, etc. can be mentioned. A particularly preferred dehydrating agent is acetic anhydride because it is easy to handle and the post-treatment after the cyclodehydration reaction is simple. The amount of the dehydrating agent used is in the range of 0.2 to 30 moles per equivalent of the amic acid of the polyamic acid. In particular, the amount of carboxylic anhydride such as acetic anhydride, propionic anhydride, trichotlic anhydride, and succinic anhydride used is preferably in the range of 1 to 3 moles per equivalent of the amic acid of the polyamic acid. If 3 moles or more of carboxylic acid anhydride is used, the hydroxyl groups of the polyamic acid or the hydroxyl groups of the produced polymaleimide are esterified, resulting in a decrease in the yield of the desired polymaleimide. The organic solvents used in the method of the present invention are halogenated hydrocarbons such as dichloroethane, chloroform, and carbon tetrachloride, ketones such as acetone, methyl ethyl ketone, and methyl isobutyl ketone, formic acid, acetic acid, methyl formate, methyl acetate, and ethyl acetate. fatty acids and fatty acid esters such as tetrahydrofuran, methyl cellosolve, butyl cellosolve, ethers such as dioxane, aromatic compounds such as benzene, toluene, xylene, cresol, chlorobenzene, methanol, ethanol,
Alcohols such as propyl alcohol, nitrogen- and sulfur-containing compounds such as pyridine, N-methylpyrrolidone, dimethylformamide, dimethylacetamide, and dimethyl sulfoxide. It is also possible to use a mixture of two or more of these organic solvents. Particularly preferred organic solvents are dimethylformamide, acetone, methyl ethyl ketone, and dioxane. The amount of organic solvent used is preferably 1 to 40 times the amount (weight ratio) of the polyamic acid to be produced. The catalysts for the cyclodehydration reaction used in the method of the present invention include lithium, copper, aluminum, magnesium,
Compounds of metals selected from calcium, zinc, chromium, titanium, vanadium, manganese, iron, nickel and cobalt, including halides, hydroxides; nitrates, sulfates,
Inorganic acid salts such as carbonates, phosphates, perchlorates;
Organic acid salts such as formate, acetate, propionate, butyrate, stearate, naphthenate, benzoate; various complexes such as acetylacetonant complex; and lower salts such as sodium acetate or potassium acetate. Sodium or potassium salts of carboxylic acids; organic acids such as p-toluenesulfonic acid, trichloroacetic acid, trifluoroacetic acid, etc. Particularly preferred catalysts are nickel acetate or lithium bromide. Further, the tertiary amines used in the method of the present invention include trialkylamines in which the alkyl group has 1 to 14 carbon atoms, such as trimethylamine, triethylamine, tripropylamine, and tributylamine, and N,N'-dimethylbenzylamine; N,
N,N',N-tetramethylethylenediamine,
N,N'-diethylcyclohexylamine, N-
Methylmorpholine, N-methylpiperidine, 1,
4-diazabicyclo[2,2,2]octane and the like. A particularly desirable tertiary amine is triethylamine. In the dehydration cyclization reaction in the method of the present invention, a mixture consisting of a polyamic acid, a dehydrating agent, a catalyst, a tertiary amine and an organic solvent is heated at a temperature generally in the range of 30 to 120°C, preferably in the range of 40 to 80°C. This is carried out by stirring for a period of time ranging from 1 to 10 hours, preferably from 1 to 6 hours. If the reaction temperature is below 30℃, the reaction will be slow and it will take a long time, and if the reaction temperature is 120℃
If the above and the reaction time exceeds 6 hours, side reactions such as esterification of the hydroxyl groups of the polyamic acid or the produced polymaleimide, and polymerization of these compounds themselves will occur, resulting in a lower yield of the desired polymaleimide. decreases. After the reaction is completed, a poor solvent such as water in which the polymerimide is not soluble or hardly soluble is added to the reaction solution, or the reaction solution is added to a poor solvent to precipitate the polymaleimide, which is separated from the mother liquor by a known separation operation. High purity polymaleimide is obtained by washing the separated polymaleimide with water and drying it. Further, when washing the polymaleimide with water, the washing effect can be further improved if washing with a weak alkaline aqueous solution such as a dilute aqueous sodium carbonate or sodium bicarbonate solution is used in combination. The polymaleimide of the present invention provides a three-dimensionally crosslinked and tough cured product through thermal polymerization and addition polymerization. In the case of thermal polymerization, heat alone may be used, or peroxide may be used as a polymerization initiator. In the case of addition polymerization, it is possible to use substances having active hydrogen, such as amines, phenols, mercaptans, and compounds having active methylene. Also,
An addition reaction between a hydroxyl group in a polymaleimide molecule and a maleimide group, an epoxy group, etc. is also possible. Furthermore, the following components can be added to the polymaleimide of the present invention as necessary. (1) Powdered reinforcing agents and fillers, such as metal oxides such as aluminum oxide and magnesium oxide, metal carbonates such as calcium carbonate and magnesium carbonate, diatomaceous earth powder, basic magnesium silicate, calcined clay, and fine powder. Silica, fused silica, crystalline silica, carbon black, kaolin, finely powdered mica, quartz powder, metal hydroxides such as aluminum hydroxide, graphite, asbestos, molybdenum disulfide, antimony trioxide, etc. Furthermore, fibrous reinforcements and fillers, such as inorganic fibers such as glass fibers, rock wool, ceramic fibers asbestos, and carbon fibers, and synthetic fibers such as paper, pulp, wood flour, linters, and polyamide fibers. The amount of these powder or fibrous reinforcing materials and fillers used varies depending on the application, but as a laminated material or molding material, up to 500 parts by weight can be used per 100 parts by weight of the polymaleimide. (2) Colorants, pigments, flame retardants such as titanium dioxide, yellow carbon black, iron black, molybedenum red, navy blue, ultramarine blue, cadmium yellow, cadmium red, red phosphorus, and other inorganic phosphorus; triphenyl phosphate and other organic phosphorus; etc. (3) Furthermore, various molding resins can be blended for the purpose of improving the properties of the resin in the final coating film, adhesive layer, resin molded product, etc. For example, epoxy resin, phenolic resin, alkyd resin, fluororesin, melamine resin, triazine resin, silicone resin, acrylic resin, polyester resin, polyurethane resin, urea resin,
Modification is possible with xylene resin, polyimide resin, polybutadiene resin, polybutene resin, rubbery polymer, thermoplastic resin, etc. In addition, methods for blending various additives and synthetic resins with this polymaleimide include heating melt mixing, kneading using a roll, kneader, etc., mixing using an appropriate organic solvent, dry mixing, etc. . Hereinafter, the present invention will be explained in more detail with reference to Examples and Application Examples. [Production example of polyamine] Example 1 In a three-necked flask equipped with a thermometer, condenser, and stirrer, 139.7 g (1.5 mol) of aniline, 30.5 g (0.25 mol) of o-hydroxybenzaldehyde, and 38 g of concentrated hydrochloric acid were charged, and water was added. under reflux (temperature 110℃)
The reaction was carried out for 5 hours. After the reaction is complete, add 10% aqueous sodium hydroxide solution.
82.5 g was added into the flask and stirring was continued for 5 minutes to form an alkaline solution in the system. Next, put the reaction solution into the separating funnel No. 1 and add 400ml of methyl isobutyl ketone.
After dissolving with water, wash with 200ml of pure water three times in total.
By-produced sodium chloride and excess sodium hydroxide were removed. Next, the solution was heated under reduced pressure (100~1 mmHg/80~
Methyl isobutyl ketone and unreacted aniline were completely removed at 180°C, and the residue was poured off at 180°C and cooled to room temperature to obtain 68.2 g of a tan solid. Example 2 The same procedure as in Example 1 was carried out except that the aldehyde in Example 1 was changed to m-hydroxybenzaldehyde to obtain 68.5 g of a reddish-brown solid. Example 3 The same procedure as in Example 1 was carried out except that the aldehyde in Example 1 was changed to p-hydroxybenzaldehyde to obtain 66.1 g of a dark red solid. Example 4 38g (0.25 mol) of vanillin was added to the aldehyde of Example 1.
The same procedure as in Example 1 was carried out except that 73.3 g of a dark red solid was obtained. Example 5 133.9 g of o-toluidine was added to the aromatic amine of Example 1.
(1.25 mol) was carried out in the same manner as in Example 1 to obtain 74.7 g of a brown solid. Example 6 133.9 g of m-toluidine was added to the aromatic amine of Example 1.
(1.25 mol) was carried out in the same manner as in Example 1 to obtain 74.5 g of a reddish-brown solid. Example 7 133.9 g of o-toluidine was added to the aromatic amine of Example 1.
(1.25 mol) and 73.9 g of a dark purple solid was obtained by carrying out the same operation as in Example 1 except that the aldehyde was changed to p-hydroxybenzaldehyde. Example 8 The aromatic amine of Example 1 was converted to o-chloroaniline.
The same operation as in Example 1 was carried out except that the amount was changed to 127.6 g (1.0 mol) to obtain 82.6 g of a brown solid. Example 9 The aromatic amine of Example 1 was converted into o-chloroaniline.
127.6g (1.0mol), aldehyde and vanillin 38g
(0.25 mol) was carried out in the same manner as in Example 1 to obtain 87.3 g of a dark purple solid. Example 10 122.1 g of o-anisidine was added to the aromatic amine of Example 1.
(1.0 mol), and 78.8 g of a dark red solid was obtained by carrying out the same operation as in Example 1 except that the aldehyde was changed to m-hydroxybenzaldehyde. Example 1 Maleic anhydride was added to a 500 ml four-necked flask equipped with a thermometer, condenser, dropping funnel, and stirrer.
41.2 g and 82.4 g of acetone were charged and stirred to dissolve maleic anhydride. Next, a solution obtained by dissolving 58.4 g of the polyamine obtained in Production Example 1 in 116.8 g of acetone was added dropwise over 1 hour while keeping the temperature of the flask at 20 to 30°C.
After the dropwise addition was completed, stirring was continued for 30 minutes at the same temperature. Next, in this flask, 1.2 g of lithium bromide,
Add 16 ml of triethylamine and 51 g of acetic anhydride,
The dehydration cyclization reaction was carried out by stirring for 2 hours while maintaining the temperature at 60°C. After the reaction is complete, drop the reaction product into water 1,
After the polymaleimide was precipitated and separated, the precipitate was washed with a large amount of water and dried to obtain 89 g of pale yellow polymaleimide (yield 98.5%). The melting point of this polymaleimide (capillary method) is 125
It was ~130℃. Example 2 Maleic anhydride was added to a 500 ml four-necked flask equipped with a thermometer, condenser, dropping funnel, and stirrer.
41.2 g and 82.4 g of N,N'-dimethylformamide were charged and stirred to dissolve maleic anhydride. Next, a solution obtained by dissolving 58.4 g of the polyamine obtained in Production Example 2 in 16.8 g of N,N'-dimethylformamide was added dropwise over 1 hour while maintaining the temperature of the flask at 20 to 30°C. Stirring was continued for 30 minutes. Next, add 0.4 g of nickel acetate into this flask.
Add 10 ml of triethylamine and 51 g of acetic anhydride,
The dehydration cyclization reaction was carried out by stirring for 5 hours while maintaining the temperature at 40°C. After the reaction is completed, the reaction product is dropped into 1 water to precipitate polymaleimide, and after separation, the precipitate is washed with a dilute aqueous sodium carbonate solution, washed with water, and dried to form pale yellow polymaleimide. g
(yield 98%). The melting point of this polymaleimide was 130-136°C. Example 3 In a 500 ml four-necked flask equipped with a thermometer, condenser, dropping funnel, and stirrer, 69.0 g of anhydrous 5-norbornene-2,3-dicarboxylic acid and N,N'-
138 g of dimethylformamide was charged and stirred to dissolve 5-norbornene-2,3-dicarboxylic acid anhydride. Next, a solution obtained by dissolving 58.4 g of the polyamine obtained in Production Example 3 in 116.8 g of N,N'-dimethylformamide was added to the solution for 1 hour while keeping the temperature of the flask at 20 to 30°C.
The mixture was added dropwise over a period of time, and after the addition was completed, stirring was continued for 30 minutes at the same temperature. Next, 0.4 g of nickel acetate, 10 ml of triethylamine, and 51 g of acetic anhydride were added to the flask, and the mixture was stirred for 2 hours while maintaining the temperature at 60°C to carry out a dehydration ring closure reaction. After the reaction is completed, the reaction product is dropped into 1 part of water to precipitate polymaleimide, and after separation, the precipitate is washed with a large amount of water and dried to form light brown polymaleimide (melting point 264-270°C). 114.7g (yield 98.5
%) was obtained. [Examples 4 to 10] Polymaleimide was obtained in the same manner as in Example 1, except that the polyamine acetone solution shown in Table 1 was used instead of the polyamine acetone solution obtained in Production Example 1. Table 1 shows the yield and the melting point of the polymaleimide.

【table】

[Table] Application example 1 50 parts of the polymaleimide obtained in Example 1 and 4,4'-
4.4 parts of diaminodiphenylmethane and 0.5 parts of 2-methylimidazole were mixed in a pressure kneader (temperature 130°C).
The mixture was kneaded for 5 minutes. After kneading, crush it with a crusher,
A yellow powder was obtained. Table 2 shows the solubility of this prepolymer (powder) in solvents. Next, transfer this powder to a press mold and heat it at 200℃20
Compression molding was performed for 10 minutes at a pressure of Kg/cm ² and cooled to 40° C. to obtain a molded product. Table 2 shows the physical properties of this molded product measuring 12.7 cm in length, 1.27 cm in width, and 0.64 cm in height. Further, this molded product was stored in a greenhouse at 250° C. for 10 hours to be post-cured, and the cured product shown in Table 2 was obtained. Example 2 40 parts of the polymaleimide obtained in Example 1 and 4,4'-
After kneading 7 parts of diaminodiphenylmethane in a pressure kneader (temperature 130°C) for 5 minutes, 16 parts of orthocresol novolac epoxy “EOCN102” (trade name manufactured by Nippon Kayaku Co., Ltd.) and 2-methylimidazole were mixed.
0.4 part was added and kneaded for further 5 minutes at the same temperature. After kneading, the mixture was pulverized using a pulverizer to obtain a yellow powder. Table 2 shows the solubility of this prepolymer in solvents. Next, a molded product was obtained in the same manner as in Example 1, and a cured product was obtained. The physical properties are shown in Table-2. Example 3 For comparison Example 1 above except that N,N'-4,4'-diphenylmethane bismaleimide was used as the polymaleimide.
In the same manner as above, a yellow powder was obtained, a molded product was obtained, and then a cured product was obtained. Solubility of prepolymers in solvents, molded products,
Table 2 shows the physical properties of the cured product.

【table】 [Brief explanation of the drawing]

FIG. 1 is an infrared absorption spectrum diagram of the polymaleimide obtained in Example 1 of the present invention, and FIG. 2 is a nuclear magnetic resonance spectrum diagram.

Claims (1)

[Claims] A polymaleimide represented by a linear formula. [In the formula, X and Y represent a hydrogen atom, a halogen atom, or an alkyl group or alkoxy group having 1 to 4 carbon atoms. D represents a divalent organic group having 2 to 30 carbon atoms and having a carbon-carbon double bond, and n is 0.
Represents an integer greater than or equal to 10 and less than or equal to 10, where m and p are 1 or 2
] 2 For 1 mole of aromatic monoaldehyde having at least one phenolic hydroxyl group in one molecule, the general formula [In the formula, X is a hydrogen atom, a halogen atom, or an alkyl group or an alkoxy group having 1 to 4 carbon atoms.] A polyamine is obtained by reacting an aromatic amine represented by the following in a proportion of 0.5 to 60 moles, and then the polyamine is A method for producing polymaleimide by adding an acid anhydride to a polyamic acid to obtain a polyamic acid, and then cyclodehydrating the polyamic acid.