JPH0131773B2 - - Google Patents

Description

[Detailed description of the invention]

[Technical Field of the Invention] The present invention relates to a method for producing a novel polyamide-imide resin composition. [Technical background of the invention] Organic insulating materials used in electrical equipment include:
Insulated wires, paints, films, laminates, impregnated resins,
Although it varies depending on the form of adhesive used, phenolic resin, polyvinyl formal resin, polyester resin, alkyd resin, epoxy resin,
Polyesterimide resin, polyamideimide resin, polyimide resin, etc. are commonly used. In recent years, due to the need for resource and energy conservation and the miniaturization and weight reduction of peripheral equipment, the high performance and miniaturization of electrical equipment itself has been progressing. The importance of organic materials is increasing. In the field of insulating paints, polyester resin paints, which have traditionally been widely used due to their relatively practical balance of heat resistance, mechanical properties, electrical properties, and economic efficiency, have recently been replaced by paints with improved heat resistance. The use of imide group-containing resin coatings such as polyesterimide, polyamideimide, and polyimide is increasing. Among imide group-containing resins, polyamide-imide resin is known to have the best balance of heat resistance, mechanical properties, electrical properties, and chemical properties. [Problems with background technology] However, conventional aromatic polyamide-imide resins
Since it is only soluble in expensive organic polar solvents such as N-methyl-2-pyrrolidone and dimethylacetamide, it has the disadvantage of increasing the price of the resin paint. Furthermore, since organic polar solvents have strong hygroscopic properties, paints using organic polar solvents as solvents also have the disadvantage of being difficult to manage during storage and use. For this reason, in the field of insulated wires that use insulating paints, there are insulated wires that use polyesterimide resin paints that are soluble in relatively inexpensive phenolic solvents such as phenol, cresol, and xylenol, at the expense of heat resistance. Double-coated wires, in which a polyester resin or polyester imide resin paint is coated on the lower layer and a polyamide-imide resin paint is applied and baked on the upper layer, are now mainly used.
Insulated wires using polyamide-imide resin paints do not have a good balance of characteristics, so they do not meet the harsh demands of current electrical equipment. Therefore, many proposals have been made for polyamide-imide resins whose solubility in organic solvents has been improved through partial aliphatic modification by using amino acids, lactams, etc. as raw materials (for example,
−17374, Special Publication 56-22330, Special Publication 1987-34210). However, when aliphatic modification is performed in which methylene chains are introduced into the molecule, as is the case with lactam, the heat resistance, especially the heat softening temperature when used as an insulated wire, is inferior to that of aromatic polyamide-imide resins. It had its drawbacks. [Summary of the Invention] The present inventor conducted intensive research to develop a polyamide-imide resin composition that has excellent solubility and contains a large amount of imide component, and as a result, discovered a polyamide-imide resin composition that has been hardly considered as a material for heat-resistant resins in the past. By using dehydrated citric acid as part of the polyhydric carboxylic acid component and reacting it with diamine, it has superior heat resistance than conventional aromatic polyamide-imide resins, and also has significantly increased solubility in organic solvents. It has been found that a polyamide-imide resin composition can be obtained. The present invention was made based on this knowledge,
(1)(A)(a) 10-90% of tricarboxylic acid and/or its derivatives containing at least 5 mol% or more of citric acid
(b) an acid component consisting of 90 to 10 mol% of an aromatic tetracarboxylic acid and/or its derivative, and (B) a diamine, in which the (A) component and (B) component are approximately equal. 1. A method for producing a polyamide-imide resin composition, which comprises blending the components so as to have a mol ratio (including cases in which one component is in excess of 10 mol % or less) and reacting in a phenolic solvent. This is what we are trying to provide. The citric acid used in the present invention can be used with or without water of crystallization, but since the reaction with diamine involves dehydration,
From the viewpoint of reaction efficiency, it is preferable to use anhydrous citric acid that does not contain water of crystallization. Examples of tricarboxylic acids other than citric acid and/or derivatives thereof include aromatic tricarboxylic acids, aromatic tricarboxylic acid esters, aromatic tricarboxylic acid anhydrides, etc. shown in () and () alone or in combination of two or more. used. R ₂ − (COOR ₁ ) ₃ ... () Here R ₁ =H, alkyl group, phenyl group,

【formula】

【formula】

【formula】

[Formula] (However, X = -CH ₂ -, -CO-, -SO ₂ -, -C(CH ₃ ) ₂ -, -O-) Generally, due to heat resistance, high reactivity, economic efficiency, etc. Trimellitic anhydride is preferred. Tetracarboxylic acids or derivatives thereof used in combination with tricarboxylic acids and/or derivatives thereof including citric anhydride include aromatic, alicyclic,
There are aliphatic ones. Examples of such tetracarboxylic acids include pyromellitic acid, 3,3',4,4'-benzophenonetetracarboxylic acid, butanetetracarboxylic acid,
3,3',4,4'-diphenyltetracarboxylic acid,
2,2′,3,3′-diphenyltetracarboxylic acid,
Bicyclo [2, 2, 2] - Octo - (7) - En -
2,3,5,6-tetracarboxylic acid, 3,3',
4,4′-diphenyl ether tetracarboxylic acid,
2,2',3,3'-diphenyl ethertetracarboxylic acid, 1,4,5,8-naphthalenetetracarboxylic acid, 2,3,6,7-naphthalenetetracarboxylic acid, 1,2,5,6 -naphthalenetetracarboxylic acid, 2,2-bis-(3,4-dicarboxyphenyl) sulfone, 2,5-bis(3,4-dicarboxyphenyl) 1,3,4-oxadiazole or these Examples include derivatives such as anhydrides and esters of. Among these tetracarboxylic acids or derivatives thereof, pyromellitic anhydride, 3,3',4,4'-benzophenonetetracarboxylic anhydride, and butanetetracarboxylic acid can be used to produce polyamide-imide resins. has excellent heat resistance, solubility, and economical efficiency, and is suitable for the present invention. If you want to increase the number of amide bonds without reducing heat resistance, use aromatic acids such as terephthalic acid, isophthalic acid, oxalic acid, malonic acid, succinic acid, glutaric acid, adipic acid, pimelic acid, suberic acid, azelaic acid, etc. Group or aliphatic dibasic acids can also be used as part of the acid component. In view of the balance between solubility in organic solvents and heat resistance, it is desirable that the proportion of citric acid in tricarboxylic acid and/or its derivatives is 5 mol% or more, and the ratio of citric acid in tricarboxylic acid and/or its derivatives to tetracarboxylic acid and It is desirable that the proportion of tricarboxylic acid and/or its derivative in the acid component consisting of tricarboxylic acid and/or its derivative is 10 mol% or more. Citric acid is less than 5 mol% in the tricarboxylic acid and/or its derivative, or tricarboxylic acid and/or its derivative is 10 mol% in the acid component.
If it is less than this, the solubility of the polyamide-imide resin composition in organic solvents, especially phenolic solvents will decrease, making it difficult to obtain a practical resin composition. Moreover, if the tetracarboxylic acid and/or its derivative is less than 10 mol % in the acid component, the imide component will decrease, and the heat resistance of the polyamide-imide resin composition will decrease. The diamine used in the present invention may be any of aliphatic, alicyclic, and aromatic diamines. Suitable diamines include ethylenediamine,
Trimethylene diamine, tetramethylene diamine, pentamethylene diamine, hexamethylene diamine, heptamethylene diamine, octamethylene diamine, nonamethylene diamine, decamethylene diamine, trimethylhexamethylene diamine, morpholine diamine, cyclohexane
Aliphatic and alicyclic diamines such as 1,4-diamine, 3,9-bis(3-aminopropyl)-2,4,8,10-tetraoxaspiro[5.5]undecane, 4,4' -diaminodiphenylmethane, 4,
4'-diaminodiphenyl ether, 4,4'-diaminodiphenylpropane, 4,4'-diaminodiphenyl sulfone, 3,3'-diaminodiphenyl sulfone, 4,4'-diaminodiphenyl sulfide, 3 , 3'-dimethyl-4,4'-diaminodiphenylmethane, 3,3'-dichloro-4,4'-diaminodiphenylmethane, 3,3'-dimethoxy-4,
4'-diaminodiphenyl, 3,3'-dimethyl-
4,4'-diaminodiphenyl, 4,4'-diaminodiphenyl, m-phenylenediamine, p-phenylenediamine, 2,4-diaminotoluene,
There are aromatic diamines such as 2,6-diaminotoluene, m-xylylene diamine, and p-xylylene diamine, which can be used alone or in combination. Part of the diamine was added to 3 for the purpose of increasing the crosslinking component.
3′,4′-triaminodiphenylmethane, 3,3′,
It can also be replaced with a trivalent or higher valent polyamine such as 4,4'-tetraaminodiphenylmethane. Among the diamines, aromatic diamines are particularly preferred from the viewpoint of heat resistance and mechanical properties of the insulating film. (A), (B) The reaction temperature and time for each reaction component vary depending on the starting materials and whether it is a solution reaction or a solvent-free reaction, but generally the reaction temperature is 90 to 350°C and the reaction time is several hours. Several 10 hours is appropriate. In the case of a solution reaction, it is affected by many factors such as the solvent used, the solid content when charging the starting materials, and the presence or absence of a catalyst, but the reaction between a carboxylic acid or its derivative and a diamine starts when the temperature exceeds 100°C. Also, in consideration of the boiling point range of the solvent generally used in this reaction, the preferable temperature range is 100 to 250°C. The reaction time is determined depending on whether the resulting resin particularly requires a polymer and is not particularly limited. The reaction in the present invention can also be carried out without a solvent, and in that case, the reaction can generally be carried out at a lower temperature and in a shorter time than in a solvent reaction. However, solution reaction is more preferable from the viewpoint of ease of obtaining the desired high polymer and usage form of the resulting resin composition. As the solvent used in the solution reaction, it is not preferable to use a solvent that reacts with the starting materials, but since the resin composition of the reaction product has excellent solubility, many organic solvents can be used. Examples of suitable solvents include phenol, o-cresol, m-cresol, p-cresol, various xylenols, and various chlorophenols.Solvents that can be used in combination with these include benzene, toluene, xylene, High boiling point aromatic hydrocarbons (for example, Maruzen Oil Co., Ltd., Swazol #1000, Swazol 1500, Nippon Oil Co., Ltd., Nisseki Hisol 100, Nisseki Hisol 150, etc.), ethylene glycol monomethyl ether acetate, and the like. Particularly preferred solvent composition is a mixed system of a phenolic solvent such as phenol, cresol, xylenol, etc. and a high boiling point aromatic hydrocarbon solvent in view of the stability of the resulting resin solution, film-forming properties, economic efficiency, etc. There is no particular limit to the solid content concentration during the reaction, but 35%
If it is less than 35%, the reaction will take a long time, side reactions will easily occur, and it will be difficult to obtain a resin composition with a high degree of polymerization, so it is more preferably 35% or more. The reaction of the present invention can be promoted by a catalyst commonly used for amidation and imidization reactions. Examples of suitable catalysts include lead monoxide, boric acid, metal salts of naphthenic acids such as lead naphthenate, zinc naphthenate, phosphoric acid, polyphosphoric acid, organotitanium compounds such as tetrabutyl titanate, triethanolamine titanate, triethylamine. , 1,8-diaza-bicyclo(5,4,0)undecene-7 (including this acid adduct), and the like. The preferred usage amount is 0.01 to 5% based on the solid content at the time of preparation.
There are no particular restrictions on the order or method of addition. The reaction molar ratio of acid component and diamine component is approximately 1:
1 is preferable, but either one can be set to 10 if necessary.
It may be in excess within the range of mol% or less. Each reaction component may be added at the same time from the start of the reaction, or one component may be dissolved in a solvent and the other components may be added into this solution at once or in several batches; there are no particular restrictions on the method of preparation. do not have. However, when using a tricarboxylic acid derivative having an acid anhydride group such as trimellitic anhydride, there is a risk of forming a precipitate in the early stage of the reaction due to the high reactivity between the acid anhydride group and the diamine. More preferred is a preparation method in which citric acid and diamine are sufficiently reacted in advance and then trimellitic acid anhydride is added afterwards. The reaction can be controlled by observing the degree of distillation of reaction water and the viscosity of the solution. Other resins can also be blended into the resin composition of the present invention, if necessary. Furthermore, a modified polyamide-imide resin can also be produced by adding other functional compounds, such as polyols, polyamines, and polycarboxylic acids, and further reacting. The polyamide-imide resin composition obtained by the present invention exhibits extremely excellent solubility in phenolic solvents due to the use of tricarboxylic acids including citric acid and/or derivatives thereof, and is soluble only in conventional organic polar solvents. It has better heat resistance than traditional aromatic polyamide-imide resin, and can be used not only in electrical insulation materials such as insulating paints, impregnated resins, laminates, films, and adhesives, but also in the fields of heat-resistant paints, fibers, and molded resins. This is extremely useful in practice. The present invention will be explained below with reference to Examples. Example 1 19.2 g of anhydrous citric acid (0.1
mol), trimellitic anhydride 153.7 g (0.8 mol), 3,3',4,4'-benzophenonetetracarboxylic anhydride 32.2 g (0.1 mol), 4,4'-diaminodiphenyl ether 200.2 g (1.0 mol), m
- 400 g of cresol was charged and the temperature was raised to 200°C over about 1 hour in a nitrogen stream. Distilled water began to come out at 140°C, and was actively distilled at 150-160°C. After continuing the reaction at a temperature of 200℃ for 5 hours, 700g of m-cresol was added and thoroughly stirred to form a reddish-brown transparent resin solution with a non-volatile content (200℃ x 1.5H) of 24.8% and a viscosity (25℃) of 53 poise. Obtained. The resulting resin solution was heated at 200°C on a 0.1 mm thick copper plate.
The coating film obtained by baking for 20 minutes at 250℃ and 30 minutes at 250℃ has sufficient flexibility, and its infrared absorption spectrum contains imide groups at 1780 cm ^-1 and 1640 to 1680 cm ^-1
A fairly broad absorption of amide groups was observed. The properties of the insulated wire obtained by coating and baking the obtained resin solution on a copper wire of 1.0 mm diameter were as shown in Table 1. Example 2 38.4 g of anhydrous citric acid (0.2
mol), trimellitic anhydride 19.2g (0.1 mol),
Butanetetracarboxylic acid 163.9g (0.7mol), 4,
198.2 g (1.0 mol) of 4'-diaminodiphenylmethane and 300 g of m-cresol were charged, and the temperature was raised to 190° C. over about 1 hour in a nitrogen stream. Distilled water began to come out at 140°C, and was actively distilled at 150-160°C. After continuing the reaction at a temperature of 190℃ for 5 hours, 400g of m-cresol and 130g of solvent naphtha were added and thoroughly stirred to produce a reddish-brown transparent resin with a non-volatile content (200℃ x 1.5H) of 30.0% and a viscosity (25℃) of 89 poise. A solution was obtained. The resulting resin solution was heated at 200°C on a 0.1 mm thick copper plate.
The coating film obtained by baking for 20 minutes at 250℃ and 30 minutes at 250℃ has sufficient flexibility, and its infrared absorption spectrum includes an imide group at 1780 cm ^-1 and a broad amide group from 1640 to 1680 cm ^-1 . Absorption was observed in each case. The properties of the insulated wire obtained by coating and baking the obtained resin solution on a copper wire of 1.0 mm diameter were as shown in Table 1. Example 3 96.1 g of anhydrous citric acid (0.5
mole), 4,4'-diaminodiphenylmethane 198.2
(1.0 mol) and 300 g of m-cresol were added thereto, and the temperature was raised to 190° C. over 1 hour in a room with a stream of nitrogen air. A dehydration reaction was observed between 140 and 170°C, and the contents became transparent at 190°C. After reacting at 190℃ for 1 hour, the internal temperature was
The temperature was lowered to 100°C, and 161 g (0.5 mol) of 3,3',4,4'-benzophenonetetracarboxylic anhydride, m-
500 g of cresol was added and the temperature was again raised to 190°C over 30 minutes. During this time, further dehydration reaction was observed. After reacting at 190℃ for 5 hours, m-cresol
Add 850g and stir well to remove non-volatile matter (200℃
A reddish-brown transparent resin solution with a viscosity (25°C) of 43 poise was obtained. The resulting resin solution was heated at 200°C on a 0.1 mm thick copper plate.
The coating film obtained by baking for 20 minutes at 250℃ and 30 minutes at 250℃ has sufficient flexibility, and its infrared absorption spectrum shows imide group absorption at 1780 cm ^-1 and amide group absorption at 1650 cm ^-1 . It was done. The properties of the insulated wire obtained by coating and baking the obtained resin solution on a copper wire of 1.0 mm diameter were as shown in Table 1. Example 4 19.2 g of anhydrous citric acid (0.1
mol), 3,3',4,4'-benzophenonetetracarboxylic anhydride 161.1g (0.5 mol), butanetetracarboxylic acid 93.7g (0.4 mol), 4,4'-diaminodiphenyl ether 200.2g (1.0 mol), (m
- 500 g of cresol was added and the temperature was raised to 180°C over about 1 hour in a nitrogen stream. A dehydration reaction was observed between 140 and 170°C. After continuing the reaction at a temperature of 180℃ for 6 hours, 750g of m-cresol and 200g of solvent naphtha were added.
Stir thoroughly to remove non-volatile content (200℃ x 1.5H), 23.0%,
A reddish-brown transparent resin solution with a viscosity (25°C) of 51.0 poise was obtained. The resulting resin solution was heated at 200°C on a 0.1 mm thick copper plate.
The coating film obtained by baking for 20 minutes at 250℃ and 30 minutes at 250℃ has sufficient flexibility, and its infrared absorption spectrum shows imide group absorption at 1780 cm ^-1 and amide group absorption at 1650 cm ^-1 . It was done. The properties of the insulated wire obtained by coating and baking the obtained resin solution on a copper wire of 1.0 mm diameter were as shown in Table 1.

【table】

【table】

Claims (1)

[Claims] 1 (A) (a) Tricarboxylic acids and/or derivatives thereof containing at least 5 mol% or more of citric acid.
90 mol% and (b) aromatic tetracarboxylic acid and/or
An acid component consisting of 90 to 10 mol% of a derivative thereof, and (B) diamine, in which the (A) component and the (B) component are approximately equimolar (within a range in which one of the components is 10 mol% or less). 1. A method for producing a polyamide-imide resin composition, which comprises blending the polyamide-imide resin composition so that the polyamide-imide resin composition is reacted in a phenolic solvent.