JPS62156122A - Heat-resistant resin composition - Google Patents

Abstract

PURPOSE:To obtain the titled composition capable of high-speed baking in a short time, for use in enameled copper wires, by blending a specific polyamidimide resin and either aromatic diisocyanate blocked with lactum or trimer therefrom in specified proportion. CONSTITUTION:The objective composition can be obtained by blending (A) 100pts.wt. of a polyamidimide resin prepared by reaction, in a polar solvent, between (i) a tribasic acid anhydride (e.g. trimellitic anhydride) and (ii) an aromatic diisocyanate (e.g. 4,4'-diphenylmethane diisocyanate), if needed, together with tetrabasic acid dianhydride in a molar ratio (i)/(ii) of 0.9-1.10 so that the reduced viscosity of the resulting resin (determined in the form of dimethyl formaide solution with a solid content 0.5g/dl) falls between 0.20 and 0.35 and (B) 1-10pts.wt. of an aromatic diisocyanate blocked with lactum or trimer therefrom.

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial Field of Application) The present invention relates to a heat-resistant resin composition for enamelled copper wire.

(Prior Art) A typical heat-resistant resin composition for enamelled copper wire is polyamide-imide varnish. Polyamide-imide varnish has excellent heat resistance, refrigerant resistance, and mechanical properties (abrasion resistance, etc.), so it is used in heat-resistant equipment, microwave oven transformers,
Widely used in electrical components and enamelled wire for refrigeration and cooling equipment. However, polyamide-imide is only soluble in special expensive polar solvents, and moreover, due to viscosity constraints, the solvent accounts for 65% or more of the varnish, making it expensive. In order to increase the economic efficiency of polyamide-imide varnishes, the molecular weight of the polyamide-imide can be lowered to reduce the viscosity (solid content in dimethylformamide to 0.59/dt!), for example.
(hereinafter referred to as ηS p/C) is 0.20 to 0.
．． 35, studies have been conducted to increase the non-volatile content of pheno to 35% by weight or more.

Although the obtained pheno has good enameled wire properties, it is difficult to bake the pheno at low speed for a long time.

Sufficient performance could not be obtained, and the effect of improving economic efficiency was only halved.

(Problems to be Solved by the Invention) The present inventor aims to provide a heat-resistant resin composition using a high-solid polyamide-imide resin that provides sufficient surface performance even when baked at high speed and in a short time. do.

(Means for Solving the Problems) The present invention uses a tribasic acid anhydride and an aromatic diisocyanate together with a tetrabasic dianhydride if necessary.

Tribasic acid anhydride/aromatic diisocyanate (molar ratio)
in a polar solvent with a ratio of 0.90 to 1.10, η3
, 7° is 0.20-0.35, and 100 parts by mass of a polyamide-imide resin obtained by reacting so that 7° is 0.20-0.35, and 1 to 10 parts by mass of a lactam-blocked aromatic diisocyanate or a trimer thereof. The present invention relates to a heat-resistant resin composition.

The tribasic acid anhydride used in the present invention includes:

From the viewpoint of heat resistance, trimellitic anhydride is preferred.

For example, tetrabasic dianhydride 1 along with tribasic acid anhydride.

Dianhydrides of pyromellitic acid, benzophenonetetracarboxylic acid, and butanetetracarboxylic acid may be used together in an amount of 20 molar or less relative to the tribasic acid anhydride.

As the aromatic diincyanate, 1, for example, 4゜4'-
Examples include diphenylmethane diisocyanate, tolylene diisocyanate, and xylene diisocyanate.
From the viewpoint of removability, it is preferable to use 4,4'-diphenylmethane diisocyanate.

The molar ratio of tribasic acid anhydride/aromatic diisocyanate is in the range of 0.90 to 1.10 in order to increase the molecular weight of the polymer.

As the polar solvent used in the present invention, basic polar solvent 9
For example, N-methyl-2-pyrrolidone, dimethylacetamide, dimethylformamide, etc. are used. In terms of properties, it is preferred to use N-methyl-2-pyrrolidone.

The polyamideimide resin used in the present invention is:

Those having a molecular weight in which the above η3,7c is in the range of 0.20 to 0.35 are used. If the molecular weight is larger than the above range, the nonvolatile content of the resin composition will be reduced and sufficient economical effects will not be obtained, while if the molecular weight is smaller than the above range, sufficient performance will not be obtained.

The lactam-blocked aromatic diisocyanate or trimer thereof used in the present invention is already a known material, and considering economic efficiency, it is preferable to use (-caprolactam) as the lactam.

As the aromatic diisocyanate blocked with lactam, diisocyanates such as 4,4'-diphenylmethane diisocyanate and tolylene diisocyanate, and trimers thereof are used.

The amount of lactam-blocked polyisocyanate used is 1 to 100 parts by mass of polyamideimide resin.
The amount is in the range of 10 parts by mass. If the amount used is more than this range, the heat resistance will decrease, and if it is less than this range, sufficient high-speed baking property will not be obtained.

The heat-resistant resin composition thus obtained is as follows.

It can be used as it is or diluted to an appropriate viscosity using a diluting solvent. Suitable diluting solvents include N-methyl-2-pyrrolidone, dimethylacetamide, dimethylformamide, xylene, and toluene.

Suitable additives 9 such as phenolic resins, melamine resins,
It is okay to use epoxy resin etc. in combination.

In addition, in the present invention, the measurement of η (reduced viscosity) Sp/
The C determination is carried out as follows. The resulting polyamideimide resin solution is diluted with N-methyl-2-pyrrolidone to a nonvolatile content of about 5% by weight. Next.

Approximately 5% by weight resin solution 129 was added to methanol 10100
O! Add dropwise to a mixer filled with water while stirring.

After stirring for about 10 minutes, the entire contents were finely pulverized to remove the residue after filtration under reduced pressure with a mouth paper, placed in a vacuum dryer, and dried at 60° C. for 3 hours under reduced pressure. The solid content obtained was 0.5g/d/! ffJN in dimethylformamide so that

(Effects of the Invention) The heat-resistant resin composition of the present invention is a high-solid type heat-resistant resin composition that provides an enameled wire with excellent heat resistance even when baked at high speed and in a short time.

[Example of real sister]

The present invention will be explained below with reference to examples.

Comparative example 1 4.4'-diphenylmethanecyinone anate 2509
, 190 g of trimellitic anhydride, 535 g of N-methyl-2-pyrrolidone in a stirrer, N2 blowing pipe, condenser,
Charge the mixture into a 4-hole flask equipped with a thermometer, and while blowing in N2, raise the temperature to 80°C and keep it warm for 2 hours. Then, the temperature was gradually raised to 130°C and kept warm for 2 hours.

After keeping warm for 2 hours, the end point of 9 synthesis was determined, and the temperature was lowered to 90°C.
25g xylene.

Add methanol 109 and keep warm for 3 hours. The resulting resin solution had a ηsp/c (o.5 g/dr) and a dimethylformamide i'ti of 0.30.

Experimental Example 1 (Production of lactam-blocked 4,4'-diphenylmethane diisocyanate) 4.4'-diphenylmethanecyinone anate 2509, ε-caprolactam 2269. 500 g of xylenolic acid was placed in a four-bottle flask similar to Comparative Example 1, and the temperature was raised to 165° C. while blowing N2, kept warm for 3 hours, and then lowered.

Nine drops of the obtained resin solution are added into sooog methanol while stirring to obtain a precipitate.

The obtained precipitate was dried under reduced pressure at 60°C for 3 hours.

A solid was obtained.

The free incyanate content of this solid is 0.1% by weight.
Further, when the solid incyanate blocking agent was analyzed by gas chromatography, the main component of the blocking agent was ε-caprolactam.

In addition, some phenolic blocking agents based on xylenolic acid were confirmed. From this.

The main component of the solid is lactam-blocked 4,4
It was found to be '-diphenylmethane diisocyanate.

Example 1 The ε-caprolactam-blocked polyisocyanate 209 obtained in Experimental Example 1 was added to the varnish 10009 obtained in Comparative Example 1, and heated at 90'C for 2 hours to obtain a uniform varnish.

Example 2 4.4'-diphenylmethane diisocyanate 2629
, 192 g of trimellitic anhydride, and 546 g of N-methyl-2-pyrrolidone were placed in a flask similar to Comparative Example 1, the temperature was raised to 100° C., and the temperature was kept for 3 hours. Then, the temperature was increased to 120'C over 3 hours, kept at 120C for 3 hours, and then lowered. η31)/C(0
, 5g7dl, dimethylformamide) was 0.28. Next, 100g of xylene and 59g of methanol. M
L-20 (melamine resin solution manufactured by Hitachi Chemical) 19 and 10 g of the lactam-blocked polyisocyanate obtained in Experimental Example 1 were added and heated at 90° C. for 1 hour to obtain a uniform varnish.

The varnishes obtained in Comparative Example 1 and Example 1.2 were baked onto a copper wire to form an enamelled wire, and its characteristics were determined. The results are shown in Table 1.

(Note 1 Baking conditions measured according to JIS C3003 Baking furnace; Pierre Furnace length 4 m Furnace temperature (outlet/center/inlet 1°C) Linear speed (m/min): 10 m/min From Table 1, Examples 1 and 2 When baked at a high temperature and for a short time compared to Comparative Example 1, the flexibility, adhesion,
It can be seen that the cut-through has been significantly improved. As described above, the heat-resistant resin composition of the present invention exhibits sufficient performance even in high-speed, short-time baking, and the present invention brings about industrially very beneficial effects.

Claims (1)

[Claims] 1. Tribasic acid anhydride and aromatic diisocyanate, optionally together with tetrabasic dianhydride, tribasic acid anhydride/aromatic diisocyanate (molar ratio) from 0.90 to 1. .1
Reduced viscosity (measured in dimethylformamide with a solid content of 0.5 g/dl) in a polar solvent as a proportion of 0.
．． 20 to 0.35, and 1 to 10 parts by mass of a lactam-blocked aromatic diisocyanate or a trimer thereof. thing. 2. The heat-resistant resin composition according to claim 1, wherein the tribasic acid anhydride is trimellitic anhydride. 3. The heat-resistant resin composition according to claim 1 or 2, wherein the aromatic diisocyanate is 4,4'-diphenylmethane diisocyanate. 4. The heat-resistant resin composition according to claim 1, 2, or 3, wherein the lactam is ε-caprolactam.