JPS5948070B2 - electrodeposition paint - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an electrodeposition paint, particularly an electrodeposition paint in which natural mica, which is an inorganic insulator, and water-dispersed varnish, which is an organic insulator, are dispersed in water.

Using natural mica powder, which is an inorganic insulator, and water-dispersed varnish, which is an organic insulator, as the dispersed phase, mica and water are deposited on a conductor by electrophoretic electrodeposition using an electrodeposition paint with water as a dispersion medium. A method of forming a composite insulating layer (hereinafter referred to as an electrodeposition layer) using a dispersed varnish and a resin is already known.
The reason why the above natural mica powder is used together with a water-dispersed varnish is that when electrodepositing only mica, the strength of the electrodeposited layer is poor, and when the object to be coated is removed from the electrodeposition bath, the mica runs off, resulting in a uniform electrodeposition layer. This is because it cannot be obtained. However, if the amount of water-dispersed varnish added is large, the resin content of the water-dispersed varnish in the electrodeposited layer formed by electrodeposition will naturally increase, and the heat resistance of the electrodeposited layer will be lower than that of the water-dispersed varnish. Becomes dependent on heat resistance. In general, water-dispersed electrodeposition varnishes with good heat resistance are hardly ever put into practical use. Therefore, in order to obtain an insulating layer that requires heat resistance, it is necessary to It is preferable that the resin content is small. On the other hand, if the resin content in the electrodeposited layer is less than 40%, the mica content increases, creating voids in the electrodeposition layer, which is not suitable as an insulating layer. In order to use it as an insulating layer, it is usually used by further impregnating it with a heat-resistant impregnating resin, but in this case, if the resin content of the electrodeposited layer increases, it becomes difficult for the impregnating resin to impregnate the electrodeposited layer. It is preferable to keep the resin content within 30% or less. Furthermore, if the resin content in the electrodeposited layer is less than 5%, the strength of the electrodeposited layer becomes extremely weak, making it difficult to withstand in practical use. However, even with a resin content of 5% or more, the strength of the electrodeposited layer was not satisfactory and there was a problem in that extreme care was required in handling. It is generally known that the mechanical strength of an electrodeposited layer is also affected by the arrangement state of mica within the electrodeposition layer, but the present inventors found that even in an electrodeposition layer with a high mica content, As a result of various studies aimed at obtaining electrodeposition paints with high mechanical strength, it was discovered that the objective could be achieved by subjecting mica to an appropriate pretreatment as described below, and the present invention has been made. I was able to complete it. That is, the gist of the present invention is to heat a mixture consisting of an organic peroxide selected from benzoyl peroxide and dikyumyl peroxide, a solvent thereof such as water or an organic solvent, and natural mica to a temperature higher than the decomposition temperature of the organic peroxide. Pretreatment of natural mica by adsorbing decomposition products onto natural mica, or natural mica is covalently combined with a vinyl monomer polymerization reaction system selected from acrylic acid, acrylate, methacrylate, vinyl acetate, and styrene to form a polymer onto natural mica. The method uses 70 to 95% by weight of pretreated natural mica and 5 to 30% by weight of water-dispersed varnish.

The electrodeposition coating material of the present invention obtained by dispersing the above components in water can significantly improve the mechanical strength of the formed electrodeposition layer. The reason why this mechanical strength improves is not clear, but by pre-treating the mica as described above, the mica in the electrodeposited layer is arranged in a layered manner, and the surface condition of the mica powder changes. Possible causes include changes in the interaction between the mica powder and the resin, and an increase in the affinity with the aqueous dispersion. The size of the natural mica used here is 20
More than 20 mesh (passes through a sieve of 20 mesh, hereinafter the same meaning).

) are preferably used. Further, as organic peroxides used for pre-treatment of natural mica, for example, benzoyl peroxide, dikymyl peroxide, etc. are preferably used, and as vinyl monomers, methacrylic acid, acrylic acid, methyl methacrylate, ethyl methacrylate, styrene, etc. are preferably used. , vinyl acetate, etc. are used alone or in combination. Further, when polymerizing the vinyl monomer, a reaction initiator such as potassium persulfate, ammonium persulfate, benzoyl peroxide, azobisisobutyronitrile, etc. is preferably used. The amount of organic peroxide used is preferably 0.5 to 5.0% by weight based on natural mica, and the amount of vinyl monomer is 0.5 to 10.0% by weight. is preferable, and a larger amount is unnecessary in consideration of the impregnability of the electrodeposited layer later.

The above-mentioned pretreatment of natural mica involves heating the necessary components together to the decomposition temperature of an organic peroxide or the polymerization temperature of a vinyl monomer to perform decomposition or polymerization. This can easily be done by filtering out the natural mica after coexisting.
In this case, there is no particular restriction on the amount of water or organic solvent used, as long as it is used at least to the extent that stirring is possible. The natural mica pretreated as described above is 70 to 95% by weight relative to 5 to 30% by weight of the water-dispersed varnish.
Electrodeposition paints can be easily obtained by dispersing these in water using known conventional techniques so that the total nonvolatile content is 5 to 40% by weight. If the total non-volatile content is lower than 5% by weight, the electrodeposited film will not be firm, and if it is higher than 40% by weight, the viscosity of the paint will be too high, and a large amount of deposits will be generated when the object to be coated is pulled out of the paint. This is undesirable because it causes defects such as a bad appearance due to adhesion. There are no particular restrictions on the type of water-dispersed varnish to be used, so it may be selected from known varnishes as desired.

The electrodeposition paint obtained as described above is suitably used, for example, for insulating armature coils of electric train motors, insulating field coils, and the like.

In addition, a known conventional technique of electrodeposition is used, and the electrodeposition voltage varies depending on the object to be coated, the electrode ratio, and the distance between electrodes, but is 10 to 30.
A good electrodeposited layer can be obtained at the 0 position. The present invention will be specifically described below with reference to Reference Examples and Examples.

Reference example 1 Bisphenol type epoxy resin (Epicoat 1001.
35 meshes or more of natural mica without surface treatment in a water-dispersed varnish whose main components are 100 parts (by weight, the same applies hereinafter), 25 parts of tetrahydrophthalic anhydride, and 3 parts of ethylene glycol (manufactured by Ciel Chemical Co., Ltd.) The powder is mixed in a ratio of 90 parts to 10 parts of the resin content of the water-dispersed varnish,
Ion-exchanged water was added and thoroughly stirred to obtain a uniformly dispersed electrodeposition coating liquid with a total nonvolatile content of 15%.

A conductor to be coated (a copper plate of 10 x 400 x 1.2 m, the same applies hereinafter) and an electrode facing it are immersed in this electrodeposition coating liquid, and a DC voltage of 50 V is applied for 30 seconds, followed by dry baking (200°C). , 1 hour) thickness 0.1
An insulating layer of 7It1 was formed, its bending strength and impact resistance were measured, and an electrodeposited layer with such mechanical properties was impregnated with an epoxy-based impregnating resin and cured to form a 0.11-It1 insulating layer. An insulating layer was obtained and the breakdown voltage was measured.

Reference Example 2 Natural mica powder of 35 mesh or more without surface treatment is added to the above water into a water-dispersed varnish consisting of 50 parts of acrylonitrile, 25 parts of styrene, 15 parts of ethyl acrylate, 5 parts of glycidyl methacrylate, and 5 parts of methacrylic acid. This was mixed in at a ratio of 85 parts to 15 parts of the resin content of the dispersed varnish, and ion-exchanged water was added and thoroughly stirred to obtain a uniformly dispersed electrodeposition coating liquid with a total non-volatile content of 20%.

This electrodeposition coating liquid was electrodeposited in the same manner as in Reference Example 1, and various properties were measured.

Reference Example 3 Into the water-dispersed varnish used in Reference Example 1, 35 mesh or more of natural mica powder baked at 600°C for 1 hour was mixed in at a ratio of 90 parts to 10 parts of the resin content of the water-dispersed varnish.
Ion-exchanged water was added and thoroughly stirred to obtain a uniformly dispersed electrodeposition coating liquid with a total non-volatile content of 15%.

This electrodeposition coating liquid was electrodeposited in the same manner as in Reference Example 1, and various properties were measured.

Reference Example 4 Into the water-dispersed varnish used in Reference Example 1, 35 mesh or more of natural mica powder baked at 600°C for 1 hour was mixed in at a ratio of 95 parts to 5 parts of the resin content of the water-dispersed varnish. ,
Ion-exchanged water was added and thoroughly stirred to obtain a uniformly dispersed electrodeposition coating liquid with a total non-volatile content of 15%.

This electrodeposition coating liquid was electrodeposited in the same manner as in Reference Example 1, and various properties were measured. Example 1 500 parts of benzene, 100 parts of natural mica of 35 mesh or more, and 2 parts of benzoyl peroxide were added to a four-loaf flask, and the temperature was raised to 75 to 80°C while stirring through nitrogen.
It was kept at that temperature for 3 hours, then cooled and washed with ethanol and then thoroughly with water.

Next, the above-mentioned pretreated natural mica powder is mixed into the water-dispersed varnish used in Reference Example 1 at a ratio of 90 parts to 10 parts of the resin content of the above-mentioned water-dispersed varnish, and ion-exchanged water may be added. By stirring, a uniformly dispersed electrodepositing paint with a total non-volatile content of 20% was obtained. This electrodeposition coating liquid was electrodeposited in the same manner as in Reference Example 1,
Various properties were measured. Example 2 500 parts of ion-exchanged water, 0.1 part of lauryl sulfate ester soda and 35 mesh or more in a four-loaf flask. 100 parts of natural mica, 2 parts of methacrylic acid, and 3 parts of methyl methacrylate were added, and while stirring through nitrogen, 65~
The temperature was raised to 75°C, and then a solution prepared by dissolving 0.05 part of potassium persulfate and 0.02 part of sodium bisulfite in 10 parts of ion-exchanged water was added, and the mixture was reacted at 65 to 75°C for 3 to 4 hours.

Filter the resulting liquid and wash with water. Next, the pretreated natural mica powder was mixed into the water-dispersed varnish used in Reference Example 1 at a ratio of 90 parts to 10 parts of the resin content of the water-dispersed varnish, and ion-exchanged water was added and stirred well. A uniformly dispersed electrodepositing paint with a total nonvolatile content of 15% was obtained. This electrodeposition coating liquid was electrodeposited in the same manner as in Reference Example 1, and various properties were measured.
Example 3 500 parts of ion-exchanged water, 0.1 part of sodium laurylbenzenesulfonate, 100 parts of natural mica with a mesh size of 35 or more, 2 parts of acrylic acid, and 5 parts of ethyl methacrylate were placed in a four-bottle flask, and the mixture was heated to 65 to 50 ml while stirring through nitrogen.
The temperature was raised to 75°C, and then a solution prepared by dissolving 0.05 part of ammonium persulfate and 0.02 part of sodium bisulfite in 10 parts of ion-exchanged water was added, and the mixture was reacted at 65 to 75°C for 3 to 4 hours.

The resulting liquid is filtered and washed with water. Next, the above-mentioned pretreated natural mica powder is mixed into the water-dispersed varnish used in Reference Example 2 at a ratio of 90 parts to 10 parts of the resin content of the above-mentioned water-dispersed varnish, and ion-exchanged water is added. The mixture was stirred to obtain a uniformly dispersed electrodeposition coating liquid having a total nonvolatile content of 10%. This electrodeposition coating liquid was electrodeposited in the same manner as in Reference Example 1, and various properties were measured. Example 4 500 parts of ion-exchanged water, 0.1 part of sodium laurylbenzenesulfonate, 100 parts of natural mica of 35 mesh or more, 5 parts of styrene, and 4 parts of ethyl acrylate were placed in a four-bottle flask, and while stirring through nitrogen, the mixture was heated to Raise the temperature to 75°C, then add 0 potassium persulfate.
．． Add a solution of 0.06 parts and 0.02 parts of sodium bisulfite dissolved in 10 parts of ion-exchanged water, and heat at 65 to 75°C for 30 minutes.
Allow to react for ~4 hours.

The resulting liquid is filtered and washed with water. Next, the pretreated natural mica powder was mixed into the water-dispersed varnish used in Reference Example 2 at a ratio of 85 parts to 15 parts of the resin content of the water-dispersed varnish, and ion-exchanged water was added and stirred well. A uniformly dispersed electrodeposition coating liquid with a total nonvolatile content of 7% was obtained. This electrodeposition coating liquid was electrodeposited in the same manner as in Reference Example 1, and various properties were measured. Example 5 500 parts of ion-exchanged water, 0.05 parts of lauryl sulfate ester soda, 100 parts of natural mica of 35 mesh or more, and 2 parts of methyl methacrylate were placed in a four-bottle flask, and the temperature was raised to 65 to 75°C while stirring through nitrogen. Then, a solution prepared by dissolving 0.02 part of potassium persulfate and 0.01 part of sodium bisulfite in 10 parts of ion-exchanged water is added, and the mixture is reacted at 65 to 75°C for 3 to 4 hours.

The obtained liquid is filtered and washed with water. Next, the above-mentioned pretreated natural mica powder was mixed into the water-dispersed varnish used in Reference Example 1 at a ratio of 80 parts to 20 parts of the resin content of the above-mentioned water-dispersed varnish, and ion-exchanged water was added and stirred well. A uniformly dispersed electrodeposition coating liquid having a total non-volatile content of 25% was obtained. This electrodeposition coating liquid was electrodeposited in the same manner as in Reference Example 1, and various properties were measured.
Example 6 The pretreated natural mica powder used in Example 2 was added to the water-dispersed varnish used in Reference Example 1, and the resin content 2 of the water-dispersed varnish was added to the water-dispersed varnish used in Reference Example 1.
The mixture was mixed at a ratio of 75 parts to 5 parts, ion-exchanged water was added, and the mixture was thoroughly stirred to obtain a uniformly dispersed electrodeposition coating liquid with a total nonvolatile content of 15%.

This electrodeposition coating liquid was electrodeposited in the same manner as in Reference Example 1, and various properties were measured. Example 7 The pretreated natural mica powder used in Example 2 was added to the water-dispersed varnish used in Reference Example 1 to reduce the resin content of the water-dispersed varnish to 5%.
95 parts to 100 parts, ion-exchanged water was added, and the mixture was thoroughly stirred to obtain a uniformly dispersed electrodeposition coating liquid with a total nonvolatile content of 15%.

This electrodeposition coating liquid was electrodeposited in the same manner as in Reference Example 1, and various properties were measured. Example 8 500 parts of ethyl cellosolve, 100 parts of natural mica, and 3 parts of dicumyl peroxide were placed in a four-roof flask, and N
, and stir at 120-130°C for about 3 hours while passing gas.

The obtained liquid was cooled and filtered, and further washed and filtered with ethanol three times, and dried to obtain treated natural mica.
An electrodeposition paint having a total nonvolatile content of 15% was obtained from 85 parts of the natural mica obtained above, 15 parts of the aqueous dispersion (resin content equivalent) used in Reference Example 1, and ion-exchanged water.

Using this electrodeposition paint, various properties were measured in the same manner as in Reference Example 1. Example 9 100 parts of natural mica and 6 parts of ion-exchanged water in a four-loaf flask
After adding 0.0 parts of ammonium persulfate and passing nitrogen gas through it for 30 minutes while stirring, the temperature was raised to 70°C, and 0.3 parts of ammonium persulfate was added.
1 part, 0.1 part of sodium bisulfite to 10 parts of ion-exchanged water
Add the dissolved solution to 1 part, then add 5 parts of vinyl acetate,
React at 70-75°C for 3 hours.

The obtained liquid is cooled, filtered, washed with water three times, and dried to obtain treated natural mica. 85 parts of the above natural mica, 15 parts of the water-dispersed paint used in Reference Example 1 (in terms of resin content), and ion-exchanged water are mixed to obtain an electrodeposition paint with a total nonvolatile content of 15%.

Using this electrodeposition paint, various properties were measured in the same manner as in Reference Example 1. Table 1 shows the characteristics measured for each sample obtained in the above reference examples and examples.

Claims (1)

[Claims] 1. A mixture consisting of an organic peroxide selected from benzoyl peroxide and dikyumyl peroxide, its solvent, and natural mica is heated to a temperature higher than the decomposition temperature of the organic peroxide to convert the decomposed product into a natural Pre-treated natural mica adsorbed on mica or natural mica coexisted with a vinyl monomer polymerization reaction system selected from acrylic acid, acrylate, methacrylate, vinyl acetate and styrene, and the polymer is adsorbed onto natural mica. Consisting of pretreated natural mica, water and water-dispersed varnish, the above-mentioned treated natural mica is 70-95% by weight with respect to 30-5% by weight of the above-mentioned water-dispersed varnish, and the total nonvolatile content is 5-40% by weight. A certain electrodeposition paint. 2. The electrodeposition paint according to claim 1, wherein the polymerization reaction system comprises water, a surfactant, and a vinyl monomer.