JPS61152734A - Polyamide-imide resin composition and production thereof - Google Patents

Abstract

PURPOSE:To produce a composition having excellent heat-resistance and solubility and extremely high polymerization degree and useful as an electrical insulation varnish, by reacting a polybasic carboxylic acid composed of a tribasic acid anhydride containing a dibasic acid with a diamine in the presence of a polyamide resin. CONSTITUTION:(A) A polybasic carboxylic acid composed of tribasic acid anhydride or its derivative and containing >=5mol% dibasic acid or its derivative based on the whole acid component, is made to react with (B) a diamine at an equivalent ratio of about 1:1 in the presence of (C) a polyamide resin. The reaction is carried out in a phenolic solvent and a composition having excellent film-forming property can be produced by adding (D) an aromatic polyisocyanate masked with a phenolic compound to the reaction solution. The tribasic acid anhydride (derivative) of the component A is trimellitic anhydride, etc., and the component B is an aromatic diamine.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field of the Invention] The present invention relates to a polyamide-imide resin composition useful as an electrically insulating varnish, etc., and a method for producing the same.

[Technical background of the invention and its problems] In recent years, with 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. Polyamide resins, which have well-balanced mechanical properties, electrical properties, and economic efficiency, are becoming increasingly important in the field of insulating materials including electrical insulating varnishes.

Conventionally, a polyamide-imide resin composition with a high degree of polymerization can be obtained by reacting trimellitic anhydride and aromatic diamine in an aprotic polar solvent such as N-methyl-2-pyrrolidone or dimethylacetamide. is publicly known.

However, this method has the disadvantage that storage and management of the varnish is difficult because the polar solvent used is highly hygroscopic and pseudo-gelling phenomena, clouding phenomena, etc. tend to occur when the varnish is used. Furthermore, since a special aprotic polar solvent is used, the varnish is expensive and has poor industrial utility.

For this reason, many proposals have been made for polyamide-imide resins using phenolic solvents, which are extremely commonly used, as solvents for electrical insulating varnishes (for example,
-23999, Special Publication No. 56-17374, Special Publication No. 56
No. 6-22330, Special Publication No. 5G-34210).

However, even if an attempt is made to obtain a polyamideimide resin by simply reacting trimellitic anhydride with an aromatic diamine such as 4,4'-diaminodiphenylmethane in a phenolic solvent, a cloudy precipitate or a homogeneous solution is obtained. Even if the reaction is carried out at a high temperature above the boiling point of the phenolic solvent, aryl esters and the like are formed at the ends, making it impossible to obtain a high molecular weight polymer that can be used as a practical insulating varnish.

In addition, when aliphatic dicarboxylic acids, lactams, etc. are used, the solubility in phenolic solvents improves, but the drawback is that the heat resistance, especially the heat softening temperature when used as an insulated wire, is inferior to that of aromatic polyamide-imide resins. have.

When aromatic dicarboxylic acids or their derivatives are used in place of aliphatic dicarboxylic acids to improve heat resistance, their lower reactivity results in resins with sufficient molecular weight to produce practical coatings. The reality is that there is no such thing.

Therefore, the conventional method to obtain aromatic polyamide resin is to use aromatic dicarboxylic acid dichloride as the acid component, but this method requires a special reactor because hydrogen chloride is the elimination component. However, in the case of electrically insulating varnishes, there have been disadvantages such as the need for a step of dissolving the resin in a solvent after it is produced.

[Object of the Invention] The present inventor has conducted various studies on the reactions of dibasic acid anhydrides, tribasic acid anhydrides, and aromatic diamines, and has found that in the coexistence of polyamide resin, these produce resins with an extremely high degree of polymerization. , and the coexisting polyamide resin and the produced aromatic polyamide resin are integrated to obtain a new polyamide resin with excellent heat resistance and solubility. It has been found that by blending an aromatic polyisocyanate, a resin with even better film-forming properties can be obtained.

The present invention was made based on this knowledge, and an object of the present invention is to provide a polyamide-imide resin composition that eliminates the above-mentioned drawbacks and a method for producing the same.

[Summary of the Invention] That is, the present invention comprises (a) a polyhydric carboxylic acid component consisting of a tribasic acid anhydride or a derivative thereof containing at least 5 moles or more of a dibasic acid or a derivative thereof based on the entire acid component;
(b) A polyamide-imide resin composition obtained by reacting diamine in a ratio of approximately 1:1 in the coexistence of a polyamide resin, and a resin obtained as described above. The present invention relates to polyamide-imide resin compositions characterized in that the compositions further contain an aromatic polyisocyanate masked with a phenol, and to methods for producing the same.

The dibasic acids or derivatives thereof used in the present invention include:
For example, aromatic dibasic acids, aromatic dibasic acid esters, and the like represented by formula (I) are used.

'R+ 0OC-R2-GOOR+ ・・・・・・(
I) Generally, isophthalic acid and terephthalic acid are preferred from the viewpoint of reactivity, economy, etc.

Examples of tribasic acid anhydrides or derivatives thereof used in the present invention include aromatic tribasic acids represented by formulas (It) and (III), aromatic tribasic acid esters, aromatic tribasic acid anhydrides, etc. is used.

R4(GOOR3) 3 (I) Generally, trimellitic anhydride is preferred from the viewpoints of heat resistance, high reactivity, economic efficiency, etc.

In addition, in the present invention, a portion of the tribasic acid anhydride or its derivative, dibasic acid or its derivative used is a small amount, for example, less than 5 mol% of the entire acid component, such as pyromellitic anhydride,
Tetrabasic acid anhydrides such as 3.3', 4.4'-benzophenonetetracarboxylic anhydride, 3.3', 4.4'-diphenyltetracarboxylic anhydride, butanetetracarboxylic anhydride, or derivatives thereof , oxalic acid, malonic acid, succinic acid, glutaric acid, adipic acid, pimelic acid, speric acid, azelaic acid, and other aliphatic dibasic acids or derivatives thereof.

The diamines used in the present invention include aliphatic, alicyclic,
Aromatic diamines are mainly used.

Suitable diamines include ethylenediamine, trimethylenediamine, tetramethylenediamine, pentamethylenediamine, hexamethylenediamine, heptamethylenediamine, octamethylenediamine, nonamethylenediamine, decamethylenediamine, trimethylhexamethylenediamine, morpholinediamine, and cyclohexane. -1
,4-diamine, 3.9-bis(3-aminopropyl)-2,4,8,10-tetraoxaspiro[5.5
] Aliphatic and alicyclic diamines such as undecane, 4.4-
-diaminodiphenylmethane, 4.4-diaminodiphenyl ether, 4.4=-diaminodiphenylpropane, 4,4'-diaminodiphenyl sulfone, 3.3-
-diaminodiphenylsulfone, 4,4'-diaminodiphenylsulfite, 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, -1-phenylenediamine , p-phenylenediamine, 2.4-diaminotoluene, 2.6-diaminotoluene, -xylylenediamine, p-xylylenediamine, and other aromatic diamines, which can be used alone or in combination. A portion of the diamine was added to 3.3-. for the purpose of increasing the crosslinking component. 4-monotriaminodiphenylmethane, 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.

The polyamide resin coexisting in the reaction of tribasic acid anhydride or its derivative, dibasic acid or its derivative, and diamine has a repeating amide group as a main part of the polymer chain, and an alkylene group bonded to it. It is usually a linear synthetic polymer made by gathering a large number of molecules with a molecular weight i
Nylon of o, ooo or higher can be used.

Such nylons include, for example, nylon 6, nylon 66, nylon 610, nylon 11, nylon 12,
There are also copolymerized nylons obtained by mixing and polymerizing two or more types of homonylon monomers.
These can be used alone or in combination.

The reaction between the tribasic acid anhydride or its derivative, dibasic acid or its derivative as the acid component in (a), and the diamine in (b) in the coexistence of a polyamide resin is carried out at 150 to 250°C in the presence of an organic solvent. This is carried out by reacting at a temperature of 2 to 20 hours.

Suitable organic solvents for the present invention include phenol, 0-cresol, I-cresol, P-cresol, various xylenolic acids, various chlorophenols, nitrobenzene, N-methyl-2-pyrrolidone, dimethylformamide, and dimethylacetamide. , hexamethylphosphoramide, dimethyl sulfoxide, etc. Solvents that can be used in combination with these include benzene, toluene, and high-boiling hydrocarbons (for example, Maruzen Sekiyu Swazol 1000, Swazol 1500, Nippon Oil's Nippon Oil Hysol 100, etc.), ethylene glycol monomethyl ether acetate, etc.

Particularly preferred reaction solvents are phenolic solvents such as phenol, cresol, and xylenol from the viewpoints of solubility in the starting materials, stability of the resulting resin solution, film formability, economic efficiency, etc. When used as an electrically insulating varnish. A suitable solvent is a mixture of the phenolic solvent and a high boiling point aromatic hydrocarbon solvent.

The ratio of the polyhydric carboxylic acid component consisting of a tribasic acid anhydride or its derivative containing at least 5 mol % of a dibasic acid or its derivative to the total acid component in (a) and the diamine in (b). When the dibasic acid or its derivative and the tribasic acid anhydride or its derivative are each 2 equivalents and 1 equivalent per amino group of the diamine, the acid component and amine component are approximately 1:1 in equivalent ratio. preferable.

However, an excess of 10 equivalents or less of either one is within an acceptable range.

In order to increase the flexibility of the insulating coating, the ratio of dibasic acid or its derivative to tribasic acid anhydride or its derivative in (a) is at least 5% of the total acid component. It is preferable that it is contained in an amount of mol or more. flexibility,
In order to improve the adhesion with the conductor and the crazing resistance, it is more preferable to use 20 mol% or more of the dibasic acid or its derivative.

Although the function of the polyamide resin in the reaction of the present invention is not clear, it significantly promotes the reaction between the tribasic acid anhydride or its derivative, the dibasic acid or its derivative, and the diamine, and the resulting resin is excellent. It shows solubility, and the results of molecular weight distribution measurements using infrared charts, thermogravimetric analysis, and gel permeation chromatography indicate that the aromatic polyamide-imide resin produced and the polyamide resin used during synthesis react with each other and become integrated. It is assumed that the polyamide resin exhibits a matrix effect in the reaction between the tribasic acid anhydride or its derivative, the dibasic acid or its derivative, and the diamine, and at the same time, a polymerization reaction occurs mainly in the amide group of the polyamide resin. It is considered that this is happening. Therefore, the proportion of polyamide resin used can be varied depending on the amount sufficient to produce the matrix effect, the intended use of the resulting resin, and the required properties. For example, when used as an electrically insulating varnish, the amount is preferably 3 to 40% by weight based on the total resin content. If it is less than 3% by weight, a sufficient matrix effect will not be exhibited, and if it exceeds 40% by weight, the heat resistance of the enamelled wire obtained from the insulating varnish will decrease.

On the other hand, when used as a film or molded product, it is possible to use polyamide resin in an amount of 40% by weight or more depending on the required properties.

(a) The tribasic acid anhydride or its derivative, the dibasic acid or its derivative, and (b) the diamine and polyamide resin may be added at the same time at the start of the reaction, or one component may be dissolved in a solvent. Other ingredients can be added all at once or in several batches, and there are no particular restrictions on the method of addition.

However, in order to obtain a high molecular weight polyamide-imide resin, it is particularly preferable to charge the polyamide resin from the start of the reaction.

On the other hand, when used as an electrically insulating varnish, the reaction proceeds even during the baking step to form an enamel film, so the polyamide resin can be added relatively late in the reaction in the varnish synthesis stage.

Although the reaction proceeds satisfactorily in the absence of a catalyst, the reaction of the present invention can be accelerated with a catalyst commonly used for diamine reactions.

Examples of suitable catalysts include - lead oxide, boric acid, metal salts of naphthenic acids such as lead naphthenate and zinc, phosphoric acid, polyphosphoric acid, triethylamine, etc. The preferred amount used is based on the solid content at the time of charging. It is 0.01 to 5% of precious metals.

The reaction in a phenolic solvent starts at around 70°C with decarbonation gas bubbling, and usually at a temperature of 180 to 210°C.
A practical high molecular weight polyamide-imide resin can be obtained under reaction conditions of 3 to 12 hours at .degree.

The polyamide-imide resin composition thus obtained can be used as it is as an electrical insulating varnish, etc.
In particular, when used as an electrical insulating varnish for enameled wire production in recent high-speed, high-efficiency printing machines, it has the disadvantage that it tends to foam during wire production.

As a result of further investigation into these problems, it was found that the above-mentioned difficulties could be greatly improved by blending an aromatic polyisocyanate masked with phenols into the polyamide-imide resin solution.

Examples of aromatic polyisocyanates masked with phenols include 4,4'-diphenylmethane diisocyanate, 2,4-tolylene diisocyanate, 2,6-tolylene diisocyanate, m-xylylene diisocyanate, p-xylylene diisocyanate, 4 .4--
Polyisocyanate derivatives in which the isocyanate groups of diphenyl ether diisocyanate are masked with phenols such as phenol, cresol, and xylenol can be used. The proportion of polyisocyanate used is preferably 3 to 40% by weight based on the entire resin. If it is less than 3% by weight, foaming will occur easily, and if it exceeds 40% by weight, the flexibility and abrasion resistance of the enameled wire will decrease. Furthermore, there is no particular restriction on the temperature when adding the masked aromatic polyisocyanate, but if stirring is continued for a long time around 200°C, the resin solution may become partially opaque and precipitate.
The temperature at which it is added is preferably 140°C or lower.

The resin composition of the present invention can also be blended with other resins if necessary. Furthermore, a modified polyamide-imide resin composition can also be prepared by adding other polyfunctional compounds, such as polyols, polyamines, and polycarboxylic acids, and further reacting.

[Embodiments of the invention] The present invention will be explained in detail with reference to Examples below.

Example 1 Trimellitic anhydride 960 (0.5 mol), isophthalic acid 83G (0.5 mol), 4.4 g was added to a 3N4 Turow flask equipped with a thermometer, stirrer, cooling tube, and nitrogen inlet tube.
'-Diaminodiphenylmethane 19ag (1.0 mol)
, nylon 6 (Amiran CM 1007 manufactured by Toshisha) 40
4001 J of Q, l-cresylic acid (JIS K2451, equivalent to Metaphresyl Lumi No. 911) was charged, and the temperature was raised from room temperature to 200° C. over about 1 hour in a nitrogen stream. Foaming of decarbonized gas occurred frequently at around 140°C and continued up to around 200°C.

After foaming is almost completed, 5g of boric acid is added and the reaction temperature is raised to 20%.
The temperature was set at 0 to 215°C, and the reaction was carried out at normal pressure while refluxing cresol. The contents were initially reddish brown and opaque, but
After 1 hour, it became a clear solution.

The reaction was continued for 7 hours while refluxing the bond and cresol.
After 10 hours in total, m-cresol 5009 was added to stop the reaction. Aromatic polyisocyanate (manufactured by Nippon Polyurethane Co., Ltd., MS-50,4,4', containing about 50% by weight as diphenylmethane diincyanate) 8
0 g was added and thoroughly stirred to form a homogeneous solution.

This resin solution is reddish-brown, transparent, and has a viscosity of 78 voids (at 30°C).
), and when adjusted with cresol, it had a non-volatile content of 31.8% (200°C x 90 minutes).

This resin solution is 10ca+ length, 3ca+ width, thickness o, 1
When the coating was applied evenly to a coating thickness of approximately 15 μm on a +nl copper plate and heated at 230°C for 30 minutes, the copper plate was heated at 180°.
A flexible coating film was obtained that did not cause cracks even when bent.

Furthermore, coating and baking was carried out seven times on a 1.0++φ copper wire at a furnace length of 7m and a furnace temperature of 450-380-270°C (from top to bottom) at a line speed of 12++/sin to obtain an insulated wire with a coating thickness of 35μ.

The properties measured according to JIS C3003 and NEMA MWlooG are shown in Table 1.

(Left below) Next, we measured the infrared spectrum of this wire coating, and found that
The amide absorption bands near 1660 cm and 1530 crl were much stronger than the imide ring absorption bands at 1780 cm and 1720 ci, and it was recognized that this was a resin composition mainly composed of amide bonds.

Furthermore, thermogravimetric analysis of the film was carried out in air at a heating rate of 10° C./min, and it showed a single thermal decomposition curve with a 10% weight loss point of 440°C and a 50% weight loss point of 535°C.

Example 2 Using the same equipment as Example 1, trimellitic anhydride qe
(7 (0,5 mol) isophthalic acid 83G (0,5 mol), 4,4-diaminodiphenyl ether 200i
J (1.0 mol), 28 g of nylon 6 (Amilan CM1007 manufactured by Toshi Co., Ltd.), m-cresylic acid (JIS
K2451 metacresylic acid No. 1 equivalent) 256 (
1 was charged, and the temperature was raised from room temperature to 200°C over about 1 hour in a nitrogen stream. Foaming due to decarbonation gas was observed at around 160°C, and as soon as the foaming was almost finished, the contents also became transparent.

The reaction was further carried out for 4 hours and 30 minutes at 200 to 205°C, for a total of 6 hours and 30 minutes, and 400 g of ■-Cresal was added to stop the reaction. When the contents reached 100°C, the masked aromatic polyisocyanate (Japanese) Made by Polyurethane Co., Ltd. M
S-50,4,4'-diphenylmethane diisocyanate (containing approximately 50% by weight) 1209 was added and stirred sufficiently until a homogeneous solution was obtained.

Next, when diluted with a mixed solvent of I-cresol/solvent naphtha = 1/3 to give a viscosity of 44 voids (30°C), the non-volatile content was 30.1% by weight (200°C
A reddish-brown clear solution was obtained with 90 min).

The characteristics of the baked wire obtained under the same conditions as in Example 1 are as follows.
Shown in the table.

Examples 3 to 6 Using the same equipment as in Example 1 and under the starting material synthesis conditions shown in Table 2, reddish-brown transparent resin solutions were obtained in each case. The characteristics of the baked wire obtained under the same conditions as in Example 1 are shown in Table 3.

(Margins below) Table 2 (Margins below) Notes: *1 TMA; trimellitic anhydride IPA: isophthalic acid TPA: terephthalic acid DAM: 4,4--diaminodiphenylmethane DD
A: a, a--diaminodiphenyl ether nylon 6; Amiran CM 1007 manufactured by Toshisha Co., Ltd. Nylon 66: 〃 0M3oo1〃Nylon 6
10;〃 0M2oo1〃*2 BMD I: Using MS-50 manufactured by Nippon Polyurethane Co., Ltd. B
TDI: Addition amount calculated as the amount of polyisocyanate before using Bayer's Dismodule CT staple and not masking.

(Hereinafter in the margin) Table 3 (Hereinafter in the margin) [Effects of the invention] As is clear from the above examples, the polyamide-imide resin composition of the present invention has good heat resistance and high molecular weight mechanical properties. It is possible to form an excellent coating.

Claims (13)

[Claims] (1) (a) A polyhydric carboxylic acid consisting of a tribasic acid anhydride or a derivative thereof containing at least 5 mol % or more of a dibasic acid or a derivative thereof based on the total acid component, and (b) a diamine, A polyamide-imide resin composition characterized in that it is reacted in the coexistence of a polyamide resin at an equivalent ratio of approximately 1:1. (2) The polyamide-imide resin composition according to claim 1, wherein the tribasic acid anhydride or its derivative is an aromatic tribasic acid anhydride. (3) The polyamide-imide resin composition according to claim 1 or 2, wherein the aromatic tribasic acid anhydride is trimellitic anhydride. (4) The polyamide-imide resin composition according to any one of claims 1 to 3, wherein the dibasic acid or its derivative is an aromatic dibasic acid or its derivative. (5) The polyamide-imide resin composition according to any one of claims 1 to 4, wherein the diamine is an aromatic diamine. (6) Any one of claims 1 to 5, wherein the polyamide resin is one or more selected from nylon 6, nylon 66, nylon 610, nylon 11, nylon 12, or copolymerized nylon. The polyamide-imide resin composition according to item 1. (7) (a) Tribasic acid anhydride or its derivative containing at least 5 mol % or more of dibasic acid or its derivative based on the entire acid component and (b) diamine in an equivalent ratio of approximately 1:1. A polyamide-imide resin composition characterized in that an aromatic polyisocyanate masked with a phenol is blended into a resin composition obtained by reacting in the coexistence of a polyamide resin at a ratio of . (8) The polyamide-imide resin composition according to claim 7, wherein the tribasic acid anhydride or its derivative is an aromatic tribasic acid anhydride. (9) The polyamide-imide resin composition according to claim 7 or 8, wherein the aromatic tribasic acid anhydride is trimellitic anhydride. (10) The polyamide-imide resin composition according to any one of claims 7 to 9, wherein the dibasic acid or its derivative is an aromatic dibasic acid or its derivative. (11) The polyamide-imide resin composition according to any one of claims 7 to 10, wherein the diamine is an aromatic diamine. (12) Polyamide resin is nylon 6, nylon 66,
The polyamide-imide resin composition according to any one of claims 7 to 11, comprising one or more types selected from nylon 610, nylon 11, nylon 12, and copolymerized nylon. (13) (a) A polyhydric carboxylic acid component consisting of a tribasic acid anhydride or a derivative thereof containing at least 5 moles of a dibasic acid or its derivative based on the total acid component, and (b) an aromatic diamine. , a polyamide-imide resin composition characterized in that it is reacted in the coexistence of a polyamide resin in a phenolic solvent at an equivalent ratio of approximately 1:1, and further contains an aromatic polyisocyanate masked with a phenol. Production method.