JPS62265368A - Production of electrodeposition coating composition - Google Patents

Abstract

PURPOSE:To obtain the title compsn. composed of a stable emulsion which gives a coating film which does not cause blistering and has an excellent appearance, by allowing an org. high-molecular material having imide and/or amide groups which are cyclized at a specified ratio, dissolved in a solvent to drop into a liquid which is a non-solvent for said high-molecular material to thereby mix them and emulsify the high-molecular material therein. CONSTITUTION:At least one member (A) selected from the group consisting of an org. high-molecular material (a) having imide groups which are cyclized at a cylization ratio of not lower than 90% such as a compd. of formula I, an org. high-molecular material (b) having amide groups such as a compd. of formula II and an org. high- molecular material (c) having imide and amide groups which are cyclized at a cylization ratio of not lower than 90%, such as a compd. of formula III (in the formulas, R1 is a group of formula IV or V; R2 and R3 are each a group of formula VI or VII; and R4 is R1 or a group of formula VII) is dissolved in a solvent (B) such as N-methyl-2-pyrrolidone, dimethylacetamide, dimethyl sulfoxide, etc. The resulting soln. in allowed to drop into a liquid (C) which is a non-solvent for the component A, such as ketone, to thereby mix them and emulsify the component A in the liquid, thus obtaining the title compsn. composed of a stable emulsion.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for producing a novel electrodeposition coating composition suitable for forming an electrically insulating layer of a magnet wire and a conductor of various electrical and electronic devices. .

Until now, most of the known electrodeposition coating compositions have been made by dissolving or dispersing an acrylic polymer in water or a mixture of water and an organic solvent. It was mostly used for surface coating of automobiles, home appliances, building materials, etc., and was only used in a limited number of fields for electrical insulation. The advantages of electrodeposition coating compositions are:
The film thickness can be easily adjusted by controlling voltage and current, and a uniform film thickness can be coated even on perforated areas and uneven areas. When applied to the field of electronic materials, there was a problem with heat resistance. Particularly in the field of electronic materials, most soldering processes are carried out at a temperature of 260 to 350° C. for several minutes, and conventional electrodeposition compositions mainly composed of acrylic materials have problems in terms of heat resistance.

On the other hand, Japanese Patent Application Laid-Open No. 49-21435 is an attempt to improve the heat resistance of conventional acrylic materials. 49-21427
There is an electrodeposited varnish made by emulsifying polyamic acid with an organic solvent as described in . However, when polyamic acid is used, it is necessary to finally perform imide ring closure, and when the varnish is applied to a thick film, a dehydration reaction occurs when the polyamic acid transfers to the imide ring, resulting in foaming. There's a problem. In addition, when a polyamic acid polymer is used in the emulsion concentration of cough varnish, there is a problem that a stable emulsion can only be formed at an emulsion concentration of 1.11% or less.

The inventors investigated in order to eliminate the above-mentioned drawbacks of so-called non-water emulsion varnishes that were conventionally emulsified with polyamic acid type polymers, and surprisingly, they discovered that they were able to create a completely closed imide ring. It is possible to electrodeposit a polymer having only a polyamide group, a polymer having only a polyamide group, or a polymer having both of these groups, even with an emulsion composition prepared using a solvent that dissolves these polymers and a non-solvent that does not dissolve these polymers. Furthermore, the present invention was completed by discovering that a more concentrated and stable emulsion than conventional emulsions could be obtained.

. The present invention is directed to an organic polymer that does not contain an imide precursor and has a ring-closed imide group, an organic polymer that has an amide group, and an organic polymer that does not contain an imide precursor and has a ring-closed imide group and an amide group. After dissolving at least one selected from the group consisting of lir polymers having a group of It is an object of the present invention to provide a method for producing an electrodeposition coating composition, which is characterized by forming an emulsion.

By dropwise mixing the above organic polymer solution into a liquid that is a non-solvent for the organic polymer, an unexpectedly stable emulsion is formed. The emulsion is! It can be used as a wearable coating composition, and even when it is used to coat a thick film, only the solvent evaporates and no dehydration reaction occurs due to imide ring closure. Therefore, a coating film with good appearance without foaming can be obtained.

In the present invention, (1) an organic polymer that does not contain an imide precursor and has a ring-closed imide group, (2) an organic polymer that has an amide group, and '(3)
, does not contain an imide precursor, has a ring-closed imide group and amide 2
Organic polymers such as organic polymer imide precursors having nitrogen can be used, and at least one of these may be used alone, or at least two or more of these may be used in combination. You can.

Examples of the organic polymers (1) to (3) above are shown below.

Example 1: Polyamide-imide polymer having the following structure (1) (Torlon 4001T: manufactured by Mitsubishi Kasei Corporation)
Example 2: Aromatic polyamide polymer having the following structure (2) (ATC: manufactured by Mitsubishi Paper Mills) Polymer (ULTE #100: GE,!
PI-2080: manufactured by llpjohn) The above formula (
In 1), (2), (3), and (4),
R1 is, etc., and R4 is, etc.

In the present invention, examples of the solvent that dissolves the organic polymer include N-methyl-2-pyrrolidone, N,N'-
Examples include polar solvents such as dimethylformamide, dimethylacetamide, dimethylsulfoxide, and mixtures thereof.

In addition, as a liquid that is a non-solvent for the above-mentioned wa polymer, ketone-based solvents are suitable, such as acetone,
Examples include methyl ethyl ketone, diethyl ketone, cyclohexanone, and methyl isobutyl ketone.

In the present invention, the nitrogen-containing compound required for amination of the polyamic acid polymer is not necessarily essential, but depending on the organic polymer material used, adding it will increase the chemical equivalent of the electrodeposited resin. It is preferable because there are some things. Examples of the above-mentioned tinine-containing compounds include trimethylamine, triethylamine, tri-n-propylamine, tri-n-butylamine, pyridine, and N-ethylpiperidine.

The stability of the emulsion produced tends to vary depending on the ratio of solvent and nonsolvent used for the above organic polymer.
In particular, the weight ratio (solvent/non-solvent) is 20/80 to 501.
It is preferable to adjust within a range of 50.

When using a nitrogen-containing compound, use the above solvent 1.
It is preferable to add 0.5 to 3.0 parts by weight per 00 parts by weight.

When the composition of the present invention is electrodeposited using copper, aluminum plate, iron, stainless steel, Niraken, or an alloy thereof as an anode and cured by heating, it forms a better film than when using conventional electrodeposited varnish. is obtained, and a good coating film with a small degree of foaming is formed even if it is a thick film.

Ru.

Example 1 Aromatic polyamideimide polymer, Torlon 400
1T (manufactured by Mitsubishi Kasei Corporation) 100g N-methyl-2
- After dissolving in 1900 g of pyrrolidone to obtain a 5% by weight polymer/8 solution, this solution was dropped into 2000 g of acetone to obtain an emulsion composition having a concentration of 2.5% by weight.

A voltage of 150V was applied using a 1,511ff aluminum plate with one side masked as an anode, and after charging for 40 seconds,
It was dried at 120°C for 30 minutes and then at 200°C for 30 minutes to obtain an insulating aluminum plate. A coating film with good appearance and no foaming was obtained.

Example 2 Polyetherimide ULTEMI O00 (manufactured by GE)
100g to 1900g of N-methyl-2-pyrrolidone?
After 3 solutions, the solution was dropped into 4000 g of acetone to obtain an electrodeposited varnish with a concentration of 1.6%. Electrodeposition was performed under the same conditions as in Example 1 to obtain an insulating aluminum plate.

Example 3 Aromatic polyamide polymer ATU (manufactured by Mitsubishi Paper) 100
Dissolve g in 1900 g of N-methyl-2-pyrrolidone,
It was dropped into 3000 cc of acetone to obtain an electrodeposition varnish. After electrodeposition on aluminum plate for 40 seconds at a voltage of 250μ, 120℃
After drying at 200° C. for 30 minutes and 30 minutes at 200° C., an insulating aluminum plate with a good appearance was obtained.

Comparative Example l Polyamideimide (DuPont Pyre!IL
) was diluted with 620 g of N-methyl-2-pyrrolidone, 4 g of triethylamine was added to 1410 g of acetone, and the upper liquid polyimide varnish was added dropwise with stirring to obtain an electrodeposited varnish.

After electrodeposition on an aluminum plate for 40 seconds at a voltage of 150V,
After drying at 160°C for 20 minutes and at 200°C for 120 minutes, an insulating aluminum plate was obtained.

In the case of this varnish, what happens when the coating thickness is 20μ or more?
After it@, there was a noticeable tendency for the film to shift and the appearance to deteriorate.

The attached figure shows the dielectric breakdown voltage with respect to the film thickness of the electrodeposited varnishes obtained in each of the above-mentioned Examples and Comparative Examples. The varnish obtained in Comparative Example 1 was

[Brief explanation of drawings]

The attached figure shows the dielectric breakdown voltage with respect to the film thickness of the electrodeposited varnishes obtained in each of the above-mentioned Examples and Comparative Examples.

Claims (1)

[Claims] 1. An organic polymer that does not contain an imide precursor and has a ring-closed imide group, an organic polymer that has an amide group, and an organic polymer that does not contain an imide precursor and has a ring-closed imide group and an amide group. After dissolving at least one selected from the group consisting of organic polymers in a solvent, the above organic polymer solution is mixed dropwise into a liquid that is a non-solvent for the organic polymer to form an emulsion. A method for producing an electrodeposition coating composition, characterized in that: 2. Electrode deposition according to claim 1, in which the organic polymer solution containing a nitrogen-containing base is used before dropwise mixing the organic polymer solution into a non-solvent liquid. Method for manufacturing coating composition. 3. Electrodeposition coating according to claim 1 or 2, in which N-methyl-2-pyrrolidone, N,N'-dimethylformamide, dimethyl sulfoxide, or dimethylacetamide is used as a solvent for the organic polymer. Method for manufacturing the composition. 4. A method for producing a coating composition for electrodeposition according to claim 1 or 3, in which ketones are used as the non-solvent liquid.