JPS61285211A - Polyamide-imide resin composition - Google Patents

Abstract

PURPOSE:The titled novel composition useful as electrical insulating varnish, etc., having improved heat resistance and solubility, obtained by reacting a polycarboxylic acid with a polyisocyanate in the presence of a polyamide resin to give a resin composition and reacting this resin composition with a polyhydric alcohol. CONSTITUTION:(A) A resin composition obtained by reacting (i) a polycarboxylic acid (derivative) (preferably trimellitic acid) with (ii) a polyisocyanate (deriva tive) (preferably 4,4'-diphenylmethane diisocyanate, 4,4'-diphenyl ether diiso cyanate, tolylene diisocyanate, etc.) in an equivalent ratio of 1:1 in the presence of a polyamide (nylon having >=10,000mol.wt.) is reacted with (B) preferably 5-40wt% polyhydric alcohol (preferably diphenylsilane diol), to give the aimed composition.

Description

DETAILED DESCRIPTION OF THE INVENTION (Technical Field of the Invention) The present invention includes electricity, e! The present invention relates to a novel polyamide-imide resin composition useful as an edge varnish.

(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-imide resins, which have well-balanced mechanical properties, electrical properties, and economic efficiency, are becoming increasingly important in the field of edge materials such as electrical insulation varnishes.

Conventionally, a boria ε-toimide resin composition with a high degree of polymerization has been obtained by reacting trimellitic anhydride and an aromatic diisocyanate in an aprotic polar solvent such as N-methyl-2-pyrrolidone or dimethylacetamide. It is well known that
No. 4).

However, the polar solvent used in this method is highly hygroscopic;
The problem is that it is difficult to store and manage a refined varnish that tends to cause pseudo-gelling phenomena, clouding phenomena, etc. when the varnish is used. Furthermore, the varnish that uses a special aprotic polar solvent has the disadvantage of being expensive and lacking in industrial utility.

Many proposals have been made for polyamide-imide resins using phenolic solvents, which are extremely commonly used as solvents for this reduced electric insulating varnish (for example,
No. 23999, Special Publication No. 56-17374, Special Publication No. 17374
-22330, Special Publication No. 56-3421O).

However, even if an attempt is made to obtain a polyamide-imide resin by simply reacting trimellitic anhydride with an aromatic diisocyanate such as 4,4'-diphenylmethane diisocyanate in a 7-enol 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.

If aliphatic dicarboxylic acids, lactams, etc. are used, the solubility in phenolic solvents will improve, but on the other hand, the heat resistance, especially the heat softening temperature in case of insulation, will be lower than that of aromatic polyamide-imide resins. It has the disadvantage of being inferior in comparison.

(Purpose of the Invention) The present inventor has investigated various reactions between polycarboxylic acids and aromatic polyisocyanates, and has found that a polymer with an extremely high degree of polymerization can be obtained in the reaction in the coexistence of a polyamide resin, and that Shi7? :±=&
When the polyamide resin is integrated, a new polyamide resin with excellent heat resistance and solubility is obtained, and when this resin composition is reacted with a polyhydric alcohol, a highly concentrated polyamide-imide ester resin can be obtained. The present invention has been made based on this knowledge, and it is an object of the present invention to provide a polyamide-imide resin composition free from the above-mentioned conventional drawbacks.

(Summary of the invention) That is, the present invention is characterized in that a polyhydric alcohol is reacted with a resin composition obtained by reacting a polycarboxylic acid or a derivative thereof with a polyisocyanate or a derivative thereof in the coexistence of a polyamide resin. It is an object of the present invention to provide a polyamide-imide resin composition that has the following properties.

The polycarboxylic acids conveniently used in the present invention include dibasic acids or their derivatives, tribasic acid anhydrides or their derivatives, and tetrabasic acid anhydrides or their derivatives. Acid anhydrides or derivatives thereof can be used alone or by partially replacing them with other polycarboxylic acids, and tetrabasic acid anhydrides or derivatives thereof can be used in combination with other polycarboxylic acids.

Examples of dibasic acids or derivatives thereof used here include oxalic acid, dibasic acids and dibasic acid esters represented by formula (A), and the like.

R100CR-COOR+ (1) Among these dibasic acids or derivatives thereof, aromatic dibasic acids or derivatives thereof are particularly preferred from the viewpoint of heat resistance.

Examples of tribasic acid anhydrides or derivatives thereof include citric acid, aromatic tricarboxylic acids and aromatic tricarboxylic acid esters represented by the formula (-Ni, (H#)),
Aromatic tricarboxylic acid anhydride and the like are used.

R* (COOR+) s ・----・
= (1') Generally, trimellitic anhydride is preferred from the viewpoints of heat resistance, high reactivity, economic efficiency, etc.

Tetrabasic acid anhydrides or derivatives thereof include, for example, virometic anhydride, 3.3', 4.4'-benzophenonetetracarboxylic anhydride, 3.3', 4.4'-diphenyltetracarboxylic anhydride, Examples include acid anhydrides such as naphthalenetetracarboxylic anhydride and butanetetracarboxylic anhydride, and derivatives of acids, esters, and the like.

As the polyisocyanate or its Q derivative used in the present invention, aliphatic, alicyclic, and aromatic diisocyanates are mainly used. Suitable diisocyanates include, for example, ethylene diisocyanate, trimethylene diisocyanate, tetramethylene diisocyanate, pentamethylene diisocyanate, hexamethylene diisocyanate, heptamethylene diisocyanate, octamethylene diisocyanate, nonamethylene diisocyanate, decamethylene diisocyanate, trimethylhexamethylene diisocyanate, morpholine diisocyanate,
Cyclohexane diisocyanate, 3.9-bis(3
-propyl isocyanate) 2.4,8.10-tetraoxaspiro[5.5] undecane, 4.4'-diphenylmethane diisocyanate), 4.4'-diphenyl ether diisocyanate, 4.4'-diphenylpropane diisocyanate, 4,4'-diphenylsulfone diisocyanate, 3,3'-diphenylsulfone diisocyanate, 4,4'-diphenylsulfite diisocyanate, 3,3'-dimethyl, 4,4'-diphenylmethane diisocyanate), 3 .3'-dichloro-4,
4'-diphenylmethane diisocyanate, 3.3'-
dimethyl-4,4'-bisphenyl diisocyanate,
3.3'-dimethoxy-4,4'-bisphenyl diisocyanate, 4.4'-bisphenyl diisocyanate, m-phenylene diisocyanate, p-phenylene diisocyanate, 2,4-tolylene diisocyanate,
Examples include 2,6-tolylene diisocyanate, m-xylylene diisocyanate, p-xylylene diisocyanate, and the like, and these can be used alone or in combination.

Polyisocyanates other than diincyanate include:
For example, polymethine/polyphenylpolyisocyanate, 4,4',4'-)-lisocyanate-totriphenylmethane, 2,2',5,5'-tetraisocyanate-4,4'-dimethyldiphenylmethane, 2 ,4.4
'-diphenyl ether triisocyanate, tris(
4-Methyl-3-incyanate (phenyl) isocyanate, etc. can also be used.

Further, polyisocyanate derivatives in which the incyanate group of polyisocyanate is masked with phenol, cresol, xylenol, etc. can also be used.

These polyisocyanates are appropriately selected depending on the required properties such as heat resistance and mechanical properties of the resulting polyamide-imide resin composition, but they are suitable for the heat resistance, mechanical properties, and economy of the insulating film that are particularly required as electrical insulating varnishes. From the viewpoint of properties, aromatic diisocyanates are preferred, and among them, 4
．． 4'-diphenylmethane diisocyanate, 2.4
-1-lylene diisocyanate, 2,6-tolylene diisocyanate, m-xylylene diisocyanate, p-xylylene diisocyanate, 4,4'-diphenyl ether diisocyanate, or these diisocyanates masked with phenols and derivatives thereof alone or in combination It is particularly preferable to use it as a material in order to realize the above-mentioned characteristics.

The polyamide resin coexisting during the reaction of polycarboxylic acid or its derivative with polyisocyanate or its derivative has amide groups repeated as a main part of the polymer chain, and alkylene groups are bonded to form a large number of friends. The resulting linear platform polymer usually has a molecular weight of 10.0
00 or higher nylon or aromatic polyamide resin can be used.

Examples of nylon include nylon 6, nylon 66,
There are copolymerized nylons obtained by mixing and polymerizing nylon 6101, nylon 11, nylon 12, and two or more types of homonylon monomers, and these can be used alone or in combination.

Aromatic polyamide resins include aromatic rings as acid or aluminum components, and are obtained, for example, by the reaction of aromatic dicarboxylic acids and aliphatic diamines. It also includes those that sometimes dissolve.

The reaction between polycarboxylic acid or its derivative and polyisocyanate or its derivative in the presence of polyamide resin is carried out by reacting at a temperature of 150 to 250° C. for 2 to 20 hours in the presence of an organic solvent.

Suitable organic solvents for the present invention include phenol 0-cresol, m-cresol, p-cresol, various xylenolic acids, various chlorophenols, nitrobenzene, N-methyl-2-pyrrolidone, dimethylformamide, dimethylacetamide, Examples of solvents that can be used in combination with these include hexamethylphosphoramide and dimethyl sulfoxide, and solvents that can be used in combination with these include benzene, toluene, and high-boiling hydrocarbons (e.g., Maruzen Sekiyu Swazol 1000, Swazol 1500, Nippon Oil's Nippon Oil Hysol 100, etc.) ,
Examples include ethyl glycol 7-methyl ether acetate.

%, preferred reaction solvents are phenolic solvents such as phenol, cresol, xylenol, etc., from the viewpoints of solubility for the starting materials, stability of the resulting resin solution, film formability, economical efficiency, etc. SP, is used as a gas insulating varnish. When the solvent is used, a mixture of the phenolic solvent and a high boiling point aromatic hydrocarbon solvent is suitable.

The blending ratio of polycarbo/rR or its derivative and polyisocyanate or its derivative is approximately 1 in equivalent ratio when the polycarboxylic acid or its derivative is 2 equivalents and the polyinocyanate or its derivative is 51 equivalents per isonanate group. A ratio of 1 to 1 is preferred. But either - ten thousand
An excess of less than equivalent percent is within an acceptable range.

The movement of polyamide resin in the uninvented synthesis reaction VC is
Although it is not clear, the reaction between polycarboxylic acid or its derivative and polyisocyanate or its derivative is significantly promoted, the resulting resin shows excellent specificity, and infrared chart and thermogravimetric analysis. From the molecular weight distribution measurement results using gel permeation chromatography iC, etc., it is assumed that the aromatic polyamide-imide resin produced and the polyamide resin used during synthesis react with each other and become integrated. It is considered that in the reaction between polyisocyanate or its derivative and polyisocyanate or its derivative, the polyamide resin exhibits a matrix effect and, at the same time, a polymerization reaction occurs centering on the amide group of the polyamide resin.

The proportion of this polyamide resin to be used can be varied depending on the amount sufficient to produce a matrix effect, the purpose of use of the resulting resin, and required characteristics. For example, when used as an electrical insulating varnish, 3 to 3
40% by weight is preferred. 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 40% by weight or more of polyamide resin depending on the required properties.

Polycarboxylic acid or its derivative, polyinyanate or its derivative, and polyamide resin may be charged at the same time at the start of the reaction, or the other may be charged at once or in several batches after dissolving the polymer in a solvent. There are no restrictions on the production, especially on the preparation method. However, it is particularly preferable to charge the polyamide resin from the start of the reaction in order to obtain a high molecular weight polyamide-imide resin. 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 above reaction proceeds satisfactorily in the absence of a catalyst, the reaction of the present invention can be accelerated by a catalyst commonly used in the reaction of incyanate.

Examples of suitable catalysts include - lead oxide, boric acid, metal salts of naphthenic acids such as lead naphthenate, zinc, phosphoric acid, polyphosphoric acid, triethylamine, etc. Preferred uses include solid fractionation during charging. J0.01 to 5% by weight.

The reaction is controlled within an appropriate range by observing the degree of bubbling of generated carbon dioxide and wetting of distilled water, as well as the viscosity of the resin solution.

Polyhydric alcohols used in the present invention include ethylene glycol, propylene glycol, diethylene glycol, triethylene glycol, dipropylene glycol, tripropylene glycol, 1,3-butanediol, 1,4-butanediol, 1.3- Furopanediol, neopentyl glycol, 1,6-hexane glycol, trimethylolpropane, trimethylolethane glycerin, pentaerythritol, 1,5-bentanediol, cyclohexane-1,4-diol, nrubitol, hexitol, erythritol, tris( 2-hydroxyethyl)in cyanurate, etc.

In order to further improve the adhesion and flexibility when the resin composite paraboloid of the present invention is baked onto a conductor to make an insulated wire, VC
C. It is desirable to use a trivalent or higher polyhydric alcohol as the polyhydric alcohol, especially glycerin, tris(
2-Hydroquinethyl)in cyanurate is preferred.

Further, diphenyllandiol is suitable for further improving burnout properties. When reacting the polyhydric alcohol with the polyamide-imide resin composition,
The polyhydric alcohol may be directly added to the phenolic solution of the polyamide-imide resin composition and reacted, or it may be removed and reacted with the polyamide-imide resin without a solvent or in another organic solvent. .

However, in order to improve the efficiency of the reaction and to use the final resin solution, the most suitable form is to synthesize the polyamide-imide resin solution in a phenolic solvent and then mix the polyhydric alcohol in the final stage of the reaction to continue the reaction. preferable.

Since distilled water is generated when a polyhydric alcohol is blended into the polyamide-imide resin composition, the reaction temperature is preferably in the range of 180° C. to 250° C. at which distilled water can be completely distilled off.

The reaction time for this reaction varies depending on the degree of pressure reduction in the reaction system, but is usually in the range of 1 to 10-odd hours until no distilled water is observed. The reaction can be carried out at normal pressure, but in order to facilitate the generation of distilled water, it is also possible to reduce the pressure to the extent that the phenolic solvent is distilled off.

Although this reaction can be carried out without a catalyst, it is also possible to use a catalyst commonly used in reactions using polyhydric alcohols.

Examples of such catalysts are - lead oxide, naphthenic lead,
Examples include metal salts of naphthenic acids such as zinc, organic titanium compounds such as tetrabutyl titanate, tetrapropyl titanate, and triethanolamine titanate.

The blending ratio of polyhydric alcohol is particularly important, and is set in the range of 5 to 40% by weight based on the resin content of the resin composition. ,
If it is less than 5% by weight, the resin content will not increase, while if it exceeds 40% by weight, the flexibility and heat resistance, especially the heat softening temperature, of the insulated wire will decrease, which is not preferable.

The resin solution of the polyamide-imide resin composition of the present invention is
As it is, organic titanium compounds such as tetrabutyl titanate and tetrapropyl titanate, metal salts of heptathenic acid such as zinc naphthenate, MS-50 (Proc Isocyanate manufactured by Nippon Polyurethane Co., Ltd., Desmodur CT Stable ( It can also be used as an insulating coating by adding a curing agent such as Block Incyanate (manufactured by Bayer).

(Example of the invention) The present invention will be explained in detail with reference to Examples below.

Actual example 1 Attach a thermometer, stirrer, cooling pipe, nitrogen introduction pipe, etc. - L3t
192.1f of trimellitic anhydride in 4 tube flasks
(1.0 mol) 4.4'-diphenylmethane diisocyanate 260F (1.04 mol), nylon 6 (Amiraf CM1007 manufactured by Toshi Co., Ltd.) 40f.

m-cresylic acid (JIS) K2451 (equivalent to metacresylic acid No. 1 30021) 3009 was charged, and the temperature was raised to 200° C. over about 1 hour in a nitrogen stream. Carbon dioxide gas bubbling and water oozing out were observed at 70 to 160 CVc. The reaction temperature was set at 205°C and the reaction was carried out at normal pressure. The contents, which were transparent immediately after the start of the reaction at 205°C, temporarily became opaque, but after about 2 hours, the contents became a reddish-brown, transparent, and homogeneous solution.

After 5 hours at 205°C, when the contents became a viscous solution that was difficult to stir, tris(2-hydroxyethyl)isocyanurate 402 was added at 200°C to continue the reaction. When tris(2-hydroxyethyl)isocyanurate was added, a dehydration reaction was observed, and water was distilled out along with a small amount of m-cresol. After 1 hour, the viscosity of the contents increased and stirring became difficult, so 4,001 liters of m-cresol was added to stop the reaction.

This resin solution has a non-volatile content (200'CX 1.5 hours)
The obtained resin solution, which had a viscosity of 38% by weight and 29 voids at 30°C, was 10 cm long, 3 cm wide, and 0 thick.
．． The coating was applied evenly to a copper plate of 1 cod to a thickness of about 15 μm, heated at 230°C for 30 minutes, and then the copper plate was heated to 18°C.
A flexible coating film that does not crack even when bent 0' is obtained.

According to the usual method, furnace length 7m, furnace temperature 430-380-280
(Top → Bottom) Using the obtained resin solution, the resin solution was coated and baked 7 times on a copper wire in a 1.0 coat thickness at a wire speed of 10 m/min to obtain an insulated wire with a coating thickness of about 38 μm. JIS C
3003, and the specific characteristics were as shown in Table 1.

The following margins are Table 1 Comparative Example Using the same equipment as in Example 1, trimellitic anhydride 1
92.1F (1.0 mol), 4.4'-diphenylmethane diincyane) 25 (13f (1.0 mol 8 m
-Cresylic acid (JIS K2451, metacresylic acid No. 1) 300F was charged and reacted in the same manner as in Example 1.

Similar foaming as in Example 1 was observed from 70 to 160'C, but unlike in Example 1, it became opaque immediately after 9205°C and did not become transparent even after 95 hours had passed. After 5Frf, the reaction temperature was raised to 220°C while partially distilling the cresol, and after starting the reaction at 205°C for another 3 hours, a total of 5f
Continuing the IFP reaction, a clear solution was obtained at t0.
Distilled cresol is 292. At this point, 559t of cresol was added to stop the reaction. The resulting resin solution was reddish-brown and transparent, had a nonvolatile content of 30.1% by weight, and a viscosity of 30°C.
) A friend who has 93 Boise. A coating film was created on a steel plate under the same conditions as Example 1, but cracks occurred due to 180' bending and a flexible coating film could not be obtained. Example 2 Using the same equipment and starting materials as Example 1. Used, 2o.

The reaction was continued for 5 hours at a temperature of ~205°C, and the cresol
00f7JrJ, lower the same temperature to 120℃, add diphenyllandiol 50F and gradually raise the temperature, 200℃.
React for an additional 3 hours at ℃. Non-volatile content (200℃ x 90
35%, viscosity (25°C) 32 voids.

The characteristics of an insulated wire with a film thickness of about 38 μm obtained in the same manner as in Example 1 at a line speed of 12 m/min are shown in Table 2. As is clear, the uninvented polyamide-imide resin composition has a high molecular weight, excellent mechanical properties, heat softening properties, and excellent solubility, and can also increase the nonvolatile content by modifying with polyhydric alcohol. In addition to insulating paints, it is also applicable to electric P3 edge materials such as impregnated resins, laminates, films, and adhesives, as well as heat-resistant paints, fibers, and molded resins. This is extremely useful in practice.

Claims (1)

[Claims] 1. Polycarboxylic acid or its derivative and polyisocyanate or its derivative in an equivalent ratio of approximately 1:10,
A resin composition made by reacting in the coexistence of a polyamide resin,
A polyamide-imide resin composition characterized by being formed by reacting a polyhydric alcohol. 2. The polyamide-imide resin composition according to claim 1, wherein the polycarboxylic acid or its derivative is an aromatic polycarboxylic acid. 3. The polyamide-imide resin composition according to claim 1 or 2, wherein the aromatic polycarboxylic acid is trimellitic anhydride. 4. The polyamide-imide resin composition according to any one of claims 1 to 3, wherein the polyisocyanate or its derivative is an aromatic polyisocyanate or its derivative. 5. The polyamide-imide resin composition according to any one of claims 1 to 4, wherein the aromatic polyisocyanate or its derivative is an aromatic diisocyanate or its derivative. 6, aromatic diisocyanate or its derivative is 4,4
Claim 1 consisting of one or more selected from '-diphenylmethalin isocyanate, 4,4'-diphenyl ether diisocyanate, tolylene diisocyanate, xylylene diisocyanate, and derivatives in which these diisocyanates are masked with phenols. The polyamide-imide resin composition according to any one of items 1 to 5. 7. The polyamide-imide resin composition according to any one of claims 1 to 6, wherein the polyhydric alcohol contains a hydroxyl group having a valence of 3 or more in one molecule. 8. The polyamide-imide resin composition according to any one of claims 1 to 7, wherein the polyhydric alcohol is diphenylsilanediol. 9. Claims 1 to 8, wherein the blending ratio of polyhydric alcohol is 5 to 40% by weight based on the resin content of the resin composition.
The polyamide-imide resin composition according to any one of the items listed in 1.