JPS584066B2 - Polyamideimide resin composition - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a novel polyamideimide resin composition.

More details include heat resistance, freon resistance, mechanical properties,
The present invention relates to a polyamide-imide resin composition that has excellent high-speed workability, coating film appearance, and flexibility in addition to electrical properties and can be applied mainly to enameled wire.

Currently, polyester-based boards are widely used as electrical insulating boards, especially as varnishes for enameled wires, because they have relatively well-balanced mechanical properties, electrical properties, heat resistance, etc.

However, in recent years, as electrical equipment has become smaller and lighter, there has been a demand for an enamelled wire face with even better heat resistance and freon resistance.

There are high heat-resistant faces such as polyimide faces and polyamide-imide varnishes for enameled wires that have good heat resistance and freon resistance, but they can only be dissolved in special solvents such as N-methylpyrrolidone. Because the resin itself is expensive, there is a big problem in terms of cost.

Therefore, in order to improve the heat resistance of polyester-based varnishes for enameled wires, so-called polyester imide varnishes containing imide groups as part of the resin component have been proposed.

However, although polyesterimide has improved heat resistance compared to polyester, it has drawbacks in heat softening and freon resistance, and is not as good as polyamideimide.

Therefore, many studies have been conducted to develop polyamide-imide varnishes using relatively inexpensive general-purpose solvents such as cresol, and it has been proposed to use lactams etc. as reaction components (for example, Japanese Patent Publication No. 46-29730 Publication, Special Publication No. 49-3030718, Special Publication No. 50-2
0993, JP-A-50-116591).

However, cresol-soluble polyamide-imide using lactam, etc., is actually significantly inferior to current polyamide-imide in terms of heat resistance, especially heat softening temperature and high-speed workability. .

In order to improve this thermal softening temperature, a polyisocyanate masking material containing incyanurate t[ is used as part of the incyanate compound synthesized in the presence of an appropriate masking agent such as phenols and lactams. This is described in Japanese Unexamined Patent Publication No. 52-40599.

The condensation products disclosed in this publication exhibit excellent heat softening temperatures.

The reason for this is that the condensed product obtained by using incyanurate ring-containing polyisocyanate forms a branched polymer and has thermosetting properties, and that the isocyanurate G ring, which becomes a crosslinking point during thermosetting, is excellent. It has high heat resistance, especially heat softening, which cannot be obtained with the condensation products of JP-B-46-29730 and JP-A-50-116591, which are presumed to be substantially linear polymers. It is assumed that temperature is applied.

The present invention is a polyamide containing a polyamide-imide resin soluble in cresol solvents, which has excellent coating appearance, heat softening temperature and flexibility, and exhibits sufficient performance even when baked on enameled wire at high speed. An imide resin composition is provided.

If high-speed baking properties (hereinafter referred to as high-speed workability) can be imparted to enamelled wire, high productivity and energy savings can be achieved, resulting in extremely advantageous costs, and the allowable range of baking wire speed, which is a problem in implementation, will be widened. It is also useful for improving yields.

The present inventors have conducted intensive studies on heat-resistant resins whose condensation products are branched polymers, have thermosetting properties, and have thermally stable crosslinking points. By using an appropriate amount of polycarboxylic acid or its acid anhydride, the heat resistance, especially the heat softening temperature, is significantly improved compared to the above-mentioned condensation product which is a substantially linear polymer. It was discovered that the condensation product of No. 52-40599 has high-speed workability that cannot be obtained, and the present invention was completed.

The present invention is a resin composition containing a resin and a solvent, in which polycarboxylic anhydride I other than ketopolycarboxylic anhydride, diisocyanate
, lactam■ and ketopolycarboxylic acid or its acid anhydride■, ketopolycarboxylic acid or its acid anhydride■,
This invention relates to a polyamide-imide resin composition containing a polyamide-imide resin soluble in a cresol solvent obtained by reacting lactam (1) with a diisocyanate (2) in an amount of 1 to 20 equivalent percent of the total ruboxyl equivalent and 20 to 90 equivalent percent of diisocyanate (2).

By adding an epoxy resin, an alkoxy-modified amine resin, a phenol-formaldehyde resin, or an organic acid metal salt to the above-mentioned polyamide-imide resin in the present invention, the appearance of the coating film can be improved by adding an epoxy resin, an alkoxy-modified amine resin, a phenol-formaldehyde resin, or an organic acid metal salt. Addition of polyisocyanate containing nurate i further significantly improves high-speed workability.

As the organic acid metal salt, organic acid salts of metals such as Sn, Mn, Co, and Zn are used.

It can be assumed that these additives have the effect of adding a function as a curing agent or a fluidity regulator to impart rapid curing properties and appropriate fluidity, which are insufficient when using the resin alone.

When these additives are used alone or in combination in appropriate amounts, they do not impair the heat resistance, freon resistance, mechanical properties, electrical properties, etc. of the basic resin, and they also improve flexibility, film appearance, and high-speed operation. It is possible to provide a practically extremely effective enameled wire with well-balanced properties.

The reason why excellent heat softening temperature and high-speed workability are obtained by using ketopolycarboxylic acid or its acid anhydride as a constituent component of the polyamide-imide resin in the present invention is not clear, but It is presumed that this is because the keto (carbonyl) group of the acid anhydride functions as a crosslinking point and imparts thermosetting properties.

This fact is actually supported by the fact that the polyamide-imide resin of the present invention forms a gelled product that is insoluble in cresol, which is a good solvent for the base resin, due to a sufficient thermal history for thermosetting.

Ketopolycarboxylic acid or its acid anhydride is used together with a polycarboxylic anhydride other than ketopolycarboxylic anhydride (hereinafter referred to as polycarboxylic anhydride), for example, the entire amount of polycarboxylic anhydride is If the acid or its acid anhydride is substituted, the polyamide-imide resin of the present invention, which is soluble in cresol solvents and has excellent heat resistance, flexibility, and high-speed workability, cannot be obtained.

The ketopolycarboxylic acid or its acid anhydride used in the present invention has the following general formula [wherein R, 1, and R2 may be the same or different, and a divalent compound having 1 to 12 carbon atoms] or a trivalent aliphatic hydrocarbon residue, a divalent or trivalent aromatic hydrocarbon residue having 6 to 10 carbon atoms, or a 4- to
Represents a divalent or trivalent enomoto ring residue having 12 carbon atoms.

The aromatic hydrocarbon residue may be a hydrogenated alicyclic residue or may be substituted.

Furthermore, two of the preferred trivalent residues are bonded to the acid anhydride group at adjacent positions, and one of the trivalent residues is preferably located at a non-adjacent position.

X and Y may be the same or different and are hydrogen, a carboxyl group, or an acid anhydride group bonded to adjacent carbon atoms, and n and m represent integers of 1 or 2.

For example, 4,4'-penzophenone dicarboxylic acid A2,
2'-benzophenone dicarboxylic acid A2.4'-benzophenone dicarboxylic acid, 3,4.4'-benzophenone tricarboxylic acid, 3,4,4'-benzophenone tricarboxylic acid 3,4' monoanhydride 3.3',4.4',-Benzophenonetetracarboxylic acid A3.3',4.4'.
-benzophenonetetracarboxylic dianhydride, acetone dicarboxylic acid, alpha-ketoglutaric acid, 2-acetylsuccinic acid and those listed below.

Preferred compounds include 4 and 4 in consideration of heat resistance, etc.
'-benzophenone dicarboxylic acid [A3,4,4'-benzophenone tricarboxylic acid 3,4 monoanhydride, 3,3',
4.4'-penzophenone tetracarboxylic dianhydride is mentioned.

These can be used alone or in combination.

The amount of ketopolycarboxylic acid or its acid anhydride used is important as well as the amount of lactam used, which will be described below.

If the amounts used are incorrect, it is impossible to produce a substantial heat-resistant resin.

The ketopolycarboxylic acid or its anhydride should represent 1 to 20 equivalent percent of the total carboxyl equivalent weight.

If it is too large or too small, well-balanced properties of heat resistance, flexibility, and high-speed workability will not be exhibited.

If the amount is too large, the degree of branching may increase and gelation may occur during synthesis.

Particularly preferred is a range of 3 to 10 equivalent percent.

One equivalent of acid anhydride group is treated as one equivalent of carboxyl group.

As the polycarboxylic acid anhydride used in the present invention, for example, compounds represented by the general formulas (I) and (I) are used, and the polycarboxylic acid anhydride is a carboxylic acid containing an acid anhydride group that reacts with an incyanate group or a derivative thereof. That's good.

(R is H1 alkyl group, phenyl group, etc.) (X is 10jH2-, -SO2-, -01, etc.) Generally, trimellitic anhydride is preferable in consideration of heat resistance, cost, etc. .

Along with polycarboxylic anhydride, biromellitic dianhydride, butanetetracarboxylic dianhydride, bicyclo[2,
2.2] Carboxylic dianhydrides such as monooct(7)mon-2,3,5:6-tetracarboxylic dianhydride may also be used.

As the diisocyanate, for example, tolylene diisocyanate, xylylene diisocyanate, 4,4'-diphenyl ether diisocyanate, ofthylene-1,5
-diisocyanate, aromatic diincyanate such as 4,4'-diphenylmethane diisocyanate, ethylene diisocyanate, 1,4-tetramethylene diisocyanate, 1,6-hexamethylene diisocyanate, 1.
Aliphatic diisocyanates such as 12-dodecane diincyanate, cyclobutene 1,3-diisocyanate, cyclohexane 1,3- and 1,4-diisocyanate,
Alicyclic diisocyanates such as influorone diisocyanate are used, and in consideration of heat resistance, tolylene diisocyanate, xylylene diisocyanate, 4.4'-diphenyl ether diisocyanate, 4.
, 4-sophenylmethane diisocyanate.

These can be used alone or in combination.

Similarly, lactam, which is an important raw material for cresol solvent solubilization, can generally be anything as long as it is soluble mainly in cresol solvents as an incyanate group or acid anhydride group. Considering cost, ε-cabralactam is preferable.

It is not necessary to add the amount equivalent to the incyanate group (considering the ε-monocuboid lactam as bifunctional), but if heat resistance, flexibility and solubility are comprehensively considered, the amount should be between 20 and 20 of the total incyanate equivalent. 90 equivalent percent, preferably 3
0 to 70 equivalent percent.

If it is too large or too small, the balance between heat resistance and flexibility will be compromised, and it will not be possible to obtain a product with excellent freon resistance.

From the viewpoint of heat resistance, flexibility, high-speed workability, coating film appearance, etc., the amount of incyanate component and acid component used is such that the ratio of incyanate group to carboxyl group and acid anhydride group is 1.5.
-0.7.

Preferably it is in the range of 0.9 to 1.1.

The reaction may be carried out by charging all the raw materials at the same time, but for example, one preferred method when the reaction is carried out in a cresol solvent is to charge ketopolycarboxylic acid or its acid anhydride, diincyanate, and cresol solvent,
After reacting at 200°C for 1 to 3 hours, there is a method in which a polycarboxylic acid anhydride other than the ketopolycarboxylic anhydride and a lactam are added, and the reaction is further continued at A200 to 220C for 2 to 15 hours.

According to this method, compared to the method in which all raw materials are charged at the same time, the molecular weight increases, the reaction time can be shortened, and it is advantageous for high-speed workability.

Furthermore, increasing the molecular weight is effective in improving the appearance and heat resistance of the enameled wire coating.

One preferred method when carrying out the reaction in a cresol solvent is to charge the polycarboxylic anhydride, diisocyanate, and cresol solvent together with the ketopolycarboxylic acid or its acid anhydride, and react at 160 to 200°C for 1 to 5 hours. There is a method of adding a lactam and continuing the reaction at 200 to 220°C for 2 to 15 hours.

According to this method, compared to the method in which all raw materials are charged at the same time, the molecular weight increases, the reaction time can be shortened, and it is advantageous for high-speed workability.

In addition, according to this method, it is possible to avoid the formation of aliphatic imide bonds, which are caused by the reaction of the lactam with the structure shown below and acid anhydride groups, in the resin core of the condensation product, and the heat resistance, especially Effective in improving heat softening temperature.

(represents a positive integer) One preferred method for carrying out the reaction in a cresol solvent is to charge the diincyanate, lactam and cresol solvent, react at 160 to 190°C for 1 to 3 hours, and then add the ketopolymer. There is also a method in which a polycarboxylic acid anhydride is added together with a carboxylic acid or its acid anhydride, and the reaction is further continued at 200 to 230°C for 2 to 15 hours.

This method helps prevent resin from becoming cloudy.

Furthermore, depending on the purpose, ketopolycarboxylic acid or its dianhydride, polycarboxylic acid anhydride, and lactam can be reacted first and then the remaining components are added and reacted. In order to obtain a polyamideimide resin having good flexibility, coating film appearance, and high-speed workability, ketopolycarboxylic acid or its acid anhydride, polycarboxylic acid anhydride, etc. and lactam reaction conditions must be set with the following points in mind.

That is, the lactam is not completely consumed/imidized by the amidation and imidization reactions with the ketopolycarboxylic acid or its acid anhydride, and the carboxyl group and acid anhydride group of the polycarboxylic anhydride, and the free lactam remains after the reaction. It is necessary to carry out the reaction under mild reaction conditions such that

Free lactam plays a catalytic role in promoting the reaction between the incyanate group of diisocyanate added later and the carboxyl group of ketopolycarboxylic acid or its acid anhydride and polycarboxylic acid anhydride, thereby achieving high molecular weight of the condensation product. fulfill.

The reaction is carried out in the presence or absence of a catalyst at room temperature to 350°C.
It can be carried out based on any of the above-mentioned synthesis methods within the range of °C.

When a cresol-based solution is used as a synthesis solvent, it is preferable to carry out the main reaction at a temperature exceeding 200° C. in order to obtain the polyamide-imide resin of the present invention.

This temperature is necessary in the presence of lactam to promote the reaction between incyanate groups and carboxyl groups (aromatics) and to achieve high molecular weight.

The progress of the reaction can be determined by observing the bubbles of carbon dioxide gas generated or the viscosity of the solution.

In order to avoid oral changes and proceed with a uniform reaction, caulked diisocyanates are mixed with alcohols, oximes, lactams,
It is also effective to mask it with phenol, cresol, etc., or to dissolve it in a cresol-based solvent.

The polyamide-imide resin can be made water-soluble in the presence of a basic compound, or can be suspended in water or a non-aqueous solvent.

When carrying out a solution reaction, there are no particular restrictions on the solvent other than those that inhibit the reaction.

Examples include cresol, phenol, xylenol, dimethylformamide, dimethylacetamide, N-methylpyrrolidone, etc., and a mixed solvent may be used.

Some of the synthesis solvents include aromatic organic solvents with high boiling points, such as xylene, NISSEKI HISOL-100, 150.
(trademark of aromatic hydrocarbon manufactured by Nippon Petrochemical KK), cellosolve acetate, etc. can also be used.

Cresol solvents and N-methylpyrrolidone are preferred in terms of economy and solubility.

Furthermore, the synthesis reaction of polyamideimide resin in the present invention is promoted in the presence of a catalyst.

As a synthesis catalyst, triethylamine, tributylamine, N-methylmorpholine, triethylenediamine,
Triethanolamine, 1,8-diazabisic acid (5
, 4.0) Tertiary amines such as undecene-7, organic acid metal salts such as dibutyltin dilaurate, cobalt naphthenate, cobalt octenoate, zinc naphthenate, zinc octenoate, metals such as dibutyltin oxide, lead oxide, etc. Metal alkoxides such as oxides, tetra-n-butyl titanate, tetra-n-butyl titanate, and tetraphenyl titanate, or their chelates, acylate compounds, and sulfonic acids such as p-toluenesulfonic acid A naphthalene-1,5-disulfonic acid are used. can.

When the polyamide-imide resin soluble in cresol solvents obtained in this manner is used for festivals, for example, the above-mentioned cresol solvents, polar solvents such as N-methylpyrrolidone, dimethylformamide, and dimethylacetamide can be added. etc. to a resin concentration of 20 to 40% by weight.

In this case, xylene and NISSEKIHI are used as auxiliary bath agents.
SOL-100, cellosolve acetate, etc. may be used in combination.

By adding an epoxy resin to the polyamide-imide resin in the present invention, the appearance of the coating film is significantly improved and high-speed workability is also improved.

As for the epoxy resin, the product name manufactured by Shell Co., Ltd., Epicor}
Bisphenol-based epoxy resins such as 828, 1001, 1004, and 1007, trade name manufactured by Tau Chemical Co., Ltd., Novorasoc type epoxy resins such as DEN438, and complex products such as TEPIC (tris glycidyl isocyanurate) manufactured by Shikoku Kasei Corporation. Ring-containing G-poxy resin, UCC
It is possible to use an alicyclic epoxy resin such as OH221, a trade name manufactured by Co., Ltd., and there is no restriction on the epoxy resin to be used.

The mixing ratio of epoxy resins varies depending on the type, but in general, it may be determined depending on the application within a range that does not cause phase separation.

For example, for wire enamel, the weight ratio is preferably about 1 to 30 based on the resin content in the varnish.

As a mixing method, the epoxy resin to be mixed may be dissolved in cresol in advance and added to the polyamide-imide resin, or the heated polyamide-imide resin may be directly added dropwise.

In order to avoid thickening over time after addition of the epoxy resin, it is preferable to add the epoxy resin immediately before use.

By adding an alkoxy-modified amine resin to the polyamide-imide resin in the present invention, the appearance of the coating film is significantly improved and high-speed workability is also improved.

The alkoxy-modified amino resin is obtained by subjecting an amine compound such as melamine, penzoguanamine, or urea to an addition condensation reaction with formaldehyde or paraformaldehyde, and then appropriately alkoxylating the methylol group with an alcohol such as methanol, ethanol, propanol, or butanol. It may be a co-condensate or a mixture.

The reason is unknown, but butylated penzoguanamine
Alkoxy-modified penzoguanamine formaldehyde resins such as formaldehyde resins are effective.

These addition effects are remarkable in cresol-soluble polyamide-imide resins such as those of the present invention, and such effects are not observed in existing polyamide-imide resins that are soluble in N-methylpyrrolidone (NMP)-based solvents. .

The mixing ratio varies depending on the composition of the alkoxy-modified amine resin to be mixed, the molecular weight and functional group of the resin, but generally it may be determined depending on the application within a range that does not cause phase separation.

For wire enamel, the weight ratio is preferably about 0.1 to 2.0 relative to the resin content in the face.

The mixing method is to dissolve the alkoxy-modified amino resin solution to be mixed in cresol in advance, and
It may be added to the polyamide-imide resin, or the alkoxy-modified amino resin solution may be directly added dropwise to the heated polyamide-imide resin solution.

The temperature during mixing may be in the range of room temperature to 200°C, as long as it does not cause phase separation and allows uniform mixing.

By adding phenol formaldehyde resin to the polyamide-imide resin in the present invention, the appearance of the coating film is significantly improved and high-speed workability is also improved.

As the phenol formaldehyde resin, phenol formaldehyde resins, alkylphenol formaldehyde resins, modified phenol formaldehyde resins mainly based on these resins, etc. can be used, and there are no restrictions on the type.

Examples of the modified phenol formaldehyde resin include amino compound-modified phenol formaldehyde resins such as melamine-modified phenol formaldehyde resin, penzoguanamine-modified phenol formaldehyde resin, and urea-modified phenol formaldehyde resin, and the amine compound may be the alkoxy-modified amino resin described above. good.

The mixing ratio of the phenol formaldehyde resin varies depending on the molecular weight and the type of functional group contained, but in general, it may be determined depending on the application within a range that does not cause phase separation.

For wire enamel, it is preferably about 0.1 to 30% by weight based on the resin content in the face.

As a mixing method, the phenol formaldehyde resin to be mixed may be dissolved in cresol in advance and added to the polyamide-imide resin, or the phenol formaldehyde resin may be directly added dropwise to the heated polyamide-imide resin solution. It's okay.

The polyamide-imide resin in the present invention has incyanure.
By adding a 1-ring containing polyisocyanate,
Further improved high-speed workability is obtained.

As the incyanurate ring-containing polyinsyanate,
Any compound obtained by trimerization of a polyisocyanate compound may be used, such as a trimer or incyanure containing a trimer obtained by reacting an aromatic diincyanate, particularly tolylene diisocyanate, in the presence of a tertiary amine. G-ring containing polyinsyanate mixtures are preferred.

The amount of the incyanurate ring-containing polyisocyanate to be added depends on the polyfunctionality of the polyisocyanate to be added, but for wire enamel, it is preferably about 1 to 20 kg by weight based on the resin content in the face.

A mask prepared in advance with phenol, cresol, ε-1-cubic lactam, etc. may also be used.

As for the addition method, it may be added to the polyamide-imide resin at room temperature, or it may be added directly to the heated polyamide-imide resin solution. Membrane appearance is significantly improved.

As the organic acid metal salt, for example, dibutyltinlau V
dibutyltin acetate, manganese naphthenate,
Those commonly used as dryers include manganese octenoate, cobalt naphthenate, cobalt octenoate, zinc naphthenate, and zinc octenoate, and one or more of these may be used.

The organic acid metal salt is preferably 0.01% based on the resin content.
It is added in an amount of 10 to 10% by weight, more preferably 0.1 to 5% by weight.

The organic acid metal salt and the polyamide-imide resin may be mixed at a temperature ranging from room temperature to 200° C. to ensure uniform mixing, and there are no particular limitations.

These additives may be used alone or in combination.

When used in combination, the individual effects of each are synergized.

As a preferred combination when used in combination, Z
Organic acid salt of n and phenol formaldehyde resin A phenol formaldehyde resin and alkoxy-modified amino resin, Zn metal salt and alkoxy-modified amino resin, epoxy resin and phenol formaldehyde resin, incyanurate ring-containing polyincyanate and phenol formaldehyde resin, Examples include combinations of epoxy resins, phenol formaldehyde resins and alkoxy-modified amino resins, and phenol formaldehyde resins and alkoxy-modified amino resins.

In addition, as additives other than these epoxy resins, alkoxy-modified amino resins, phenol formaldehyde resins, incyanurate ring-containing polyinsyanates, and organic acid metal salts, we also use polyethers, polyesters, polyamides, polyamideimides, polyimides, polyhydantoin. It can also be improved using polysulfone, guanidine carbonate, penzotriazole, polyesterimide, polyesteramide, furan resin, etc.

For example, tris(2-hydroxyethyl)in cyanurate, ethylene glycol, saturated polyester polyol made from terephthalic acid dimethyl ester, trinu(2-hydroxyethyl)in cyanurate, ethylene glycol, terephthalic acid dimethyl ester A4.4
'-diaminodiphenylmethane, polyesterimide made from trimellitic anhydride, 6-nylon A6
．． Examples include polyamides such as 6-i ylon and 12-nylon.

These additives are preferably added in an amount of 0.1 to 0.1 to the resin content.
It is used in a range of 30% by weight.

In addition, as a curing catalyst, tertiary amines such as triethylamine, triethyl diamine, N-methylmorpholine, N,N-dimethylethanolamine, and dimethylaniline, and alcohols such as tetrabutyl titanate and tetrapropyl titanate are added. It can also be modified.

When using a mixture of additives, the quantitative ratio is generally as follows:
It may be determined depending on the application within a range that does not cause phase separation.

For example, in the case of wire enamel, it is preferable to use the total amount of additives in a range that does not exceed 25% by weight based on the resin content.

The polyamide-imide resin composition of the present invention is used as a festival by diluting the resin content to 20 to 40% by weight, for example, with a polar solvent such as the above-mentioned cresol solvent, NMP, dimethylformamide, or dimethylacetamide.

In this case, xylene, NISSEKI HISOL-100, 15 is used as a co-solvent in consideration of resin concentration and viscosity.
0, cellosolve acetate, etc. may be used in combination.

The coating film prepared using the face prepared in this manner had good heat resistance, freon resistance, etc., as well as excellent flexibility, coating appearance, and high-speed workability.

The polyamide-imide resin composition of the present invention is mainly used as a face for wire enamel, but it can also be used for other purposes, such as as a face for sheets combined with base materials such as impregnated varnish for electrical insulation, cast varnish, and glass cloth. You can also use

The present invention will be explained by means of comparative examples and examples.

Himame + 1 Put the above ingredients into a four-bottle flask equipped with a thermometer, stirrer, and fractionator tube, and gradually raise the temperature in a nitrogen stream until 21
Raise the temperature to 0°C.

The reaction was continued at this temperature for 5 hours and then at a temperature at which the cresol refluxed for 10 hours.

A transparent face was obtained by adjusting the resin concentration to 23% by weight with cresol.

The solution viscosity of this product was 67.5 poise (30°C), and the reduced specific viscosity was 0.24 (0.5&/100ml solution of dimethylformamide).

Comparative Example 2 A festival was synthesized in the same manner as in Comparative Example 1 using the above components, and the resin concentration was adjusted to 25% by weight.

The solution viscosity of this product is 52 poise (30c), and the reduced specific viscosity is 0.24 (0.59/dimethylformamide 10
0ml solution).

Example 1 The above components except trimellitic anhydride and ε-cubic lactam were placed in a four-loaf flask equipped with a concentration meter, a stirrer, and a fractionating tube, and the temperature was raised to 200°C in a nitrogen stream for 1 hour. Carry out the reaction.

Next, the mixture is cooled to 160° C., and after adding ε-cab lactam and trimellitic anhydride, the temperature is raised to a temperature at which the cresol refluxes.

The reaction proceeded at this temperature for 9 hours.

A transparent face was obtained by adjusting the resin concentration to 25% by weight with cresol.

The solution viscosity of this product is 75 poise (30°C), and the reduced specific viscosity is Q. 27 (0.5/dimethylformamide 100
ml solution).

Example 2 Synthesized in the same manner as in Example 1 except for replacing 3.3',4,4'-benzophenonetetracarboxylic dianhydride with 4,4'-benzophenone dicarboxylic acid, and synthesized with cresol. A varnish having a resin concentration of 25% by weight was obtained.

The reduced specific viscosity of this product was 0.0.26 (0.5&/100 nl of dimethylformamide).

In the infrared absorption spectrum, both imide group absorption at 1,780 crr' and amide group absorption at 1,650 crrL-1 were observed.

Example 3 (1) Synthesis of phenol formaldehyde resin The above components were placed in a fourth flask equipped with a thermometer, a stirrer, and a reflux condenser, and refluxed for 90 minutes while stirring at 98C.

The reflux condenser was then removed and the reaction continued at a temperature of 50° C. under a reduced pressure of 30-50 MHg.

The resin was then diluted with 450μ of cresylic acid to obtain a phenol formaldehyde resin solution.

(2) Preparation of polyamide-imide resin composition containing phenol-formaldehyde resin 2 parts by weight of the above (2 parts by weight resin) per 100 parts by weight resin of the festival obtained in Example 1, which had been heated (60°C) in advance. The phenol formaldehyde resin solution synthesized in 1) was added while stirring to obtain a uniform resin solution.

Example 4 2 parts by weight of solid zinc naphthenate was added to 100 parts by weight of the resin content of the Fes obtained in Example 1, which had been heated (60C) L in advance, with stirring to form a uniform resin solution. Obtained.

Example 5 (1) Synthesis of modified phenol-formaldehyde resin The above ingredients except phthalic anhydride and inbutyl alcohol were placed in a four-neck flask equipped with a thermometer, stirrer, and reflux condenser, and heated at 98°C while stirring. Reflux for minutes.

Next, add phthalic anhydride and isobutyl alcohol V, 1
The temperature was raised to 10°C.

Reflux dehydration was performed while maintaining the temperature at 110°C.

When the dehydration reaction was completed, Buknol was taken out of the reaction system until the temperature within the reaction system rose to 130°C.

When the temperature rose to 130° C., the removal of butanol was stopped and the solution was diluted with cresylic acid to obtain a modified phenol formaldehyde resin solution with a resin concentration of 35% by weight.

(2) Preparation of polyamide-imide resin composition containing modified phenol-formaldehyde resin 4 parts by weight of the resin content of the above ( The modified phenol formaldehyde resin solution synthesized in 1) and 2 parts by weight of epoxy resin (Shell Chemicals trade name, EPIOOI) were added while stirring to obtain a uniform resin solution.

Example 6 (1) Synthesis of modified phenol-formaldehyde resin (a) Synthesis of alkoxy-modified melamine resin Add the above ingredients except phthalic anhydride to a 500 ml three-necked flask equipped with a thermometer, stirrer, and reflux condenser. The temperature was raised to 95°C at a rate of 5°C for 1 minute while stirring, and the reaction was continued for 1 hour while keeping the temperature at 95°C.

Thereafter, the mixture was cooled to 80°C, 0.3 g of phthalic anhydride was added, completely dissolved, and the temperature was raised to 110°C.

Reflux dehydration was performed while keeping the temperature at 110°C.

When the dehydration reaction was completed, butanol was taken out of the reaction system until the temperature within the reaction system rose to 130°C.

Stop debutanol when the temperature rises to 130C,
Synthesis of modified phenol-formaldehyde resin Cresylic acid, formaldehyde, and triethanolamine were placed in a four-loaf flask equipped with a thermometer, a stirrer, and a reflux condenser, and heated to 98°C. The mixture was refluxed for 90 minutes with stirring.

Next, after adding 100 g of the resin synthesized in (a), the reflux condenser was removed, and the reaction was continued at a temperature of 50 C under a reduced pressure of 30 to 50 mmHg.

Next, the resin was diluted with cresylic acid to obtain a modified phenol formaldehyde resin solution with a resin concentration of 35% by weight.

(2) Preparation of polyamide-imide resin composition containing modified phenol-formaldehyde resin 5 parts by weight of resin per 100 parts by weight of the polyamide-imide resin obtained in Example 2 which had been heated (60°C) in advance The modified phenol formaldehyde resin solution synthesized in (1) above was added with stirring to obtain a uniform resin solution.

The fests obtained as described above were used as enameled wires baked onto copper wires using a conventional method, and their properties were compared.

The results are shown in Table 1.

Wire diameter: 1mm Tie coated 8 times Furnace length: 4m Furnace temperature: Inlet 3
00°C Center 350°C Outlet 400°C Flexible heat softening temperature was measured according to JIS 0 3003.

In Comparative Example 1 and Examples 1 and 2, both showed excellent film forming properties with flexibility of 1 to 2 × OK at a linear speed of 8 m, but the comparison without using ketopolycarboxylic acid or its acid anhydride In Example 1, cracks occur even if the flexibility is elongated by 20% at a high linear speed of 9 m, and the thermal softening temperature becomes 300°C or lower, resulting in a significant loss of film-forming properties and heat resistance. In Examples 1 and 2, in which an appropriate amount of the acid anhydride was used, even at a linear speed of 9 m, the film showed excellent film forming properties and heat resistance, with a flexibility of 1 to 2 times OK and a heat softening temperature of 350°C or higher, and excellent high-speed workability. .

Furthermore, even at a thermal softening temperature at a linear velocity of 8 m, showing the same level of film-forming properties (flexibility), Examples 1 and 2 using ketopolycarboxylic acid or its acid anhydride were compared to Comparative Example 1, which did not use ketopolycarboxylic acid or its acid anhydride. It shows a significantly higher value than that of , and has excellent heat resistance.

In addition, Comparative Example 2 uses pyromellitic dianhydride as an aromatic tetracarboxylic dianhydride that does not have a keto (carbonyl) group in the molecular core, but Comparative Example 1
Similarly, at a linear speed of 9 m, film forming properties (flexibility) and heat resistance were insufficient, and no improvement in high-speed workability was observed.

The heat resistance at a linear velocity of 8 m was also poor.

This significant performance improvement in heat softening temperature and high-speed workability is due to the thermosetting reactivity of the keto(carbonyl) group of the ketopolycarboxylic acid or its acid anhydride introduced into the main chain. This is true, for example, for Joki Example 1 and Comparative Example 1.
This is clearly shown when comparing the cresol extraction residue (percentage of cresol-undissolved portion of the sample after immersing the sample in cresol at 100C for 5 hours) of the film obtained by baking the varnish obtained by baking at 250C for 15 minutes.

The baked film of Comparative Example 1 was completely dissolved in cresol and almost no undissolved parts remained (extraction residual rate 0%), whereas the baked film of Example 1 had about 60% of undissolved parts left ( The extraction residual rate was 60%), indicating that the curing reaction had progressed.

In addition, in Examples 1 and 2 and Examples 5 and 6, Examples 5 and 6 in which an appropriate amount of modified phenol formaldehyde resin or epoxy resin was used were superior in terms of linear velocity Iom compared to Examples 1 and 2 in which no modified phenol formaldehyde resin or epoxy resin was used. It showed film-forming properties and improved high-speed workability.

In addition, in Examples 1 and 2 and Examples 3 to 6, fine roughness and wrinkles occurred on the coating surface in Examples 1 and 2 where no additives were used, whereas phenol formaldehyde resin and naphthenic acid In Examples 3 to 6, in which appropriate amounts of zinc, modified phenol formaldehyde resin, and epoxy resin were used, the surface condition of the coating film was significantly improved, with no fine roughness or wrinkles on the surface of the coating film.

As is clear from the above examples, the polyamide-imide resin composition of the present invention has good heat resistance and flexibility, as well as excellent coating film appearance and high-speed workability, and can be used as a film forming material. It is industrially very effective as a gas insulation paint.

Claims (1)

[Scope of Claims] 1. A resin composition containing a resin and a solvent, which comprises, as the resin, a polycarboxylic anhydride other than a ketopolycarboxylic anhydride, a diincyanate, a lactam, and Ketopolycarboxylic acid or its acid anhydride■
is the ketopolycarboxylic acid or its acid anhydride ■ from 1 to 20 equivalent percent of the total carboxyl equivalents, and the lactam ■
A polyamide-imide resin composition comprising a polyamide-imide resin soluble in a cresol solvent obtained by reacting diisocyanate (2) with 20 to 90 equivalent percent of diisocyanate (1). 2. The polyamide-imide resin composition further contains one or more of an epoxy resin, an alkoxy-modified amine resin, a phenol formaldehyde resin, an incyanurate ring-containing polyincyanate, and an organic acid metal salt. Claim 1 consisting of
The polyamide-imide resin composition described in . 3 Keto polycarboxylic acid or its acid anhydride is 4,4
'-Benzophenone dicarboxylic acid A2. 2'-benzophenone dicarboxylic acid, 2,4'-mono-pesozophenone dicarboxylic acid, 3,4,4'-benzophenone tricarboxylic acid 3,4 monoanhydride, or 31J The polyamide-imide resin composition according to claim 1 or 2, which is '+4,4'-penzophenonetetracarboxylic dianhydride. 4. The polyamide-imide resin according to claim 1, 2, or 3, wherein the diisocyanate is 4,4-sophenylmethane diisocyanate, 4,4-phenyl ether diisocyanate, tolylene diisocyanate, or xylylene diisocyanate. Composition. 5. The polyamide-imide resin composition according to claim 1, 2, 3, or 4, wherein the 5-lactam is ε-caprolactam. 6. The polyamide-imide resin composition according to claim 1, 2, 3, 4, or 5, wherein the polycarboxylic anhydride is trimellitic anhydride. 7 Claim 1 in which the solvent is a cresol solvent
The polyamide-imide resin composition according to item 1, 2, 3, 4, 5, or 6.