JPH03243676A - Coating composition and insulated wire - Google Patents

Abstract

PURPOSE:To obtain a coating composition, composed of a compound prepared by hydrolyzing, dehydrating and condensing an alkoxide, silicone resin and inorganic filler, excellent in heat resistance and capable of providing insulated wires improved in dielectric strength after conversion into ceramics. CONSTITUTION:The objective composition obtained by blending (A) 100 pts. wt. compound prepared by hydrolyzing, dehydrating and condensing an alkoxide (e.g. a trialkoxyboron) expressed by the formula R'nM(OR)m (R is alkyl; R' is alkyl or aryl; M is metal; m is >=1; n is >=0) in a solvent with (B) 20-200 pts. wt. silicone resin and (C) 20-100 pts. wt. inorganic filler. The aforementioned composition is applied onto a conductor and baked to afford an insulated wire.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a coating composition with excellent heat resistance and an insulated wire.

(Prior Art and Problems) It has been proposed to coat a substrate or the like with a compound obtained by hydrolysis/dehydration condensation of an alkoxide to impart various properties. Properties imparted include chemical durability (acid resistance, alkali resistance, water resistance, etc.)
increase, maintain mechanical strength, adjust reflectance, color, impart electrical conductivity, etc. It has also been proposed to coat metals with the same solution, improving the corrosion resistance of metals.
It is expected to increase oxidation resistance and provide insulation properties.

In particular, it has high expectations as a coating material for metal substrates that require heat resistance.

On the other hand, insulated wires used in electrical and electronic equipment, especially stationary coils or moving coils of motors used in special high-temperature atmospheres in automobile electrical components or chemical plants, are exposed to high-temperature atmospheres that were previously unimaginable. There is a growing demand for normal driving under such conditions. Insulated wires used in such applications are required to have higher heat resistance than ever before.

In response to this demand, attempts were made to use a compound obtained by hydrolyzing and dehydrating alkoxide as an insulating layer, but the flexibility was insufficient, so it was necessary to add a resin that imparts flexibility. It has been considered. As a result, polyvinyl acetate, polyvinylalnyl, polyvinyl formal,
Polyvinyl acetal, polyvinyl butyral, etc. could be dissolved in the solvent, and the flexibility could be improved.

However, there was a problem in that the dielectric breakdown voltage of the film after ceramic was low.

[Structure of the invention]

In order to solve the above-mentioned problems, the present inventors have made extensive studies and have found the following formula: -R'nM (OR)m (wherein R is an alkyl group, R' is an alkyl group,
A coating composition consisting of a compound obtained by hydrolysis and dehydration condensation of an alkoxide represented by n (metal is n, m is an integer) in a solvent, a silicone resin, and an inorganic photonic agent is applied directly onto the conductor or otherwise. This problem was solved by applying and baking the wire through the insulator to obtain an insulated wire.

The present invention will be explained in detail below.

The alkoxide represented by the general formula RnM(OR')m used in the present invention needs to be a compound in which the hydrogen of the hydroxyl group of an alcohol is replaced with a metal having a valence of two or more, and among these, especially three Alkoxyboron, nialkoxymagnesium, trialkoxyaluminum, nialkoxysilicone, trialkoxysilicone, tetraalkoxysilicone,
Tetraalkoxytitanium and tetraalkoxyzirconium are preferred. Moreover, two or more types of these alkoxides can also be used.

Examples of trialkoxyboron compounds include trimethyl porate, triethyl porate, tripropyl porate, and tributyl porate.

Examples of the nialkoxymagnesium compounds include magnesium methoxide, magnesium ethoxide, magnesium propoxide, and magnesium toxide.

Examples of trialkoxyaluminum compounds include trimethoxyaluminum, triethoxyaluminum, tripropoxyaluminum, and tributoxyaluminum.

Examples of the nialkoxy silicon compound include dimethyljethoxylan, diphenyljethoxysilane, diphenyldimethoxylan, and the like.

Examples of trialkoxy silicon compounds include methyltrimethoxylan phenyltrimethoxysilane, methyltriethoxysilane, and phenyltriethoxysilane.

Examples of tetraalkoxy silicon compounds include tetramethoxysilane, tetraethoxysilane, and tetrabutoxysilane.

Examples of the tetraalkoxytitanium compound include tetoytyl titanate, tetraethyl titanate, tetrapropyl titanate, and tetrabutyl titanate.

Examples of the tetraalkoxyzirconium compounds include tetramethylzirconate, tetraethylzirconate, tetrapropylzirconate, and tetrabutylzirconate.

The reaction catalysts used include inorganic and organic acids or alkalis.

The silicone resin used in the present invention is R51O2/-1,
Constituent units such as R2S iO, RsSIO17°, and R102 can be used. R represents a methyl group, a phenyl group, or the like. In consideration of compatibility with the solvent and mechanical strength of the film, modified resins copolymerized with organic resins are preferred, such as alkyd, polyester, epoxy, urethane, and acrylic modified resins. Among these, polyester modification is more preferable in terms of compatibility with solvents and mechanical strength of the film.

The amount of silicone resin added is preferably 20 parts by weight to 200 parts by weight based on 100 parts by weight of a compound obtained by hydrolyzing and dehydrating an alkoxide in a solvent. If the amount is less than 20 parts by weight, the effect of adding the silicone resin will be small and the dielectric breakdown voltage after ceramicization will not be sufficient.

On the other hand, if the amount is more than 200 parts by weight, the film forming properties after ceramicization will be poor.

Any inorganic filler can be used in the present invention, such as mica, alumina, silica, barium titanate, zircon, beryllia, magnesia, clay, etc., but mica is preferable for film-forming properties. . The amount of the inorganic filler added is preferably 20 to 100 parts by weight per 100 parts by weight of the compound obtained by hydrolyzing and dehydrating an alkoxide in a solvent. If it is less than 20 parts by weight, the dielectric breakdown voltage after ceramic is insufficient, and if it is more than 100 parts by weight, the flexibility of the film will be poor.

The solvent used in the present invention is preferably an alcohol-based solvent, such as methanol, ethanol, butanol, and isopropyl alcohol. When making an insulated wire, diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, which has a high boiling point,
More preferred are solvents such as diethylene glycol monoisobutyl ether, diethylene glycol monoethyl ether, and diethylene glycol monophenyl ether.

The paint obtained from this stock is applied and baked onto a conductor directly or through another insulator to form an insulated wire. The conductor used in this case is preferably a nickel-plated copper wire from the viewpoint of melting point and oxidation resistance.

The insulated wire thus obtained can be used as is, but in order to improve the resistance to processing deterioration of the insulated wire, it is also preferable to further form a film containing an organic resin as a main component. The term "processing deterioration resistance" as used herein refers to the ability of an insulated wire to withstand damage caused when the insulated wire is used for coil forming or winding.

As the organic resin, any organic resin that can form a film can be used, but it is preferable to use a baking type organic paint because it can form a film by coating and baking like the paint of the present invention. . Among these, polyimide, polyamideimide, polyesterimide, and polyester are most preferred from the viewpoint of mechanical and thermal properties of the organic resin.

The present invention will be described in detail below based on Examples.

(Example 1) Diethylene glycol monomethyl ether (15 mol)
Tetraethoxysilane (2 mol) and water (8 mol) were dissolved in the solution, and 61% nitric acid (0.01 mol) was added to make 8
The mixture was stirred and reacted at 0°C for 5 hours to form paint A.

100 parts by weight of polyester-modified silicone resin and 50 parts by weight of mica are added to a mixture of paint A and alkoxide subjected to hydrolysis and dehydration condensation and mixed.

This paint was applied and baked on a nickel-plated copper wire with a diameter of 0.6 nunφ to obtain a film with a thickness of 8 μm.Furthermore, Bayer-ML (polyimide) was applied and baked on the upper row to form a double structure with a thickness of 16 μm. A film insulated wire was obtained.

(Comparative Example 1) Polyvinyl butyral was added to paint A prepared in Example 1.
An insulated wire was obtained in the same manner as in Example 1 except that 00 parts by weight was added.

(Example 2) An insulated wire was obtained in the same manner as in Example 1 except that 2 moles of tetraethoxysilane in Example 1 were replaced with 1 mole of tetraethoxysilane and 1 mole of methyltriethoxysilane.

(Example 3) An insulated wire was obtained in the same manner as in Example 1 except that the polyester-modified silicone resin in Example 1 was replaced with an alkyd-modified silicone resin.

(Example 4) An insulated wire was obtained in the same manner as in Example 1 except that the polyester-modified silicone resin in Example 1 was replaced with an epoxy-modified silicone resin.

(Example 5) An insulated wire was obtained in the same manner as in Example 1 except that mica in Example 1 was replaced with alumina.

(Example 6) An insulated wire was obtained in the same manner as in Example 1 except that mica in Example 1 was replaced with silica.

(Example 7) An insulated wire was obtained in the same manner as in Example 1 except that the amount of polyester-modified silicone resin added was changed to 10 parts by weight.

(Example 8) An insulated wire was obtained in the same manner as in Example 1 except that the amount of polyester-modified silicone resin added was changed to 20 parts by weight.

(Example 9) An insulated wire was obtained in the same manner as in Example 1 except that the amount of polyester-modified silicone resin added was changed to 50 parts by weight.

(Example 10) An insulated wire was obtained in the same manner as in Example 1 except that the amount of the polyester-modified silicone resin added in Example 1 was changed to 200 parts by weight.

(Example 11) An insulated wire was obtained in the same manner as in Example 1 except that the amount of polyester-modified silicone resin added was changed to 300 parts by weight.

(Example 12) An insulated wire was obtained in the same manner as in Example 1 except that the amount of mica added in Example 1 was changed to 10 parts by weight.

(Example 13) An insulated wire was obtained in the same manner as in Example 1 except that the amount of mica added in Example 1 was changed to 20 parts by weight.

(Example 14) An insulated wire was obtained in the same manner as in Example 1 except that the amount of mica added in Example 1 was changed to 50 parts by weight.

(Example 15) An insulated wire was obtained in the same manner as in Example 1 except that the amount of mica added in Example 1 was changed to 200 parts by weight.

(Example 16) An insulated wire was obtained in the same manner as in Example 1 except that diethylene glycol dimethyl ether was replaced with diethylene glycol dimethyl ether.

(Example 17) An insulated wire was obtained in the same manner as in Example 1 except that the polyimide in Example 1 was replaced with polyamideimide.

Flexibility of insulated wires obtained in the above comparative examples and examples: 600
Table 1 shows the dielectric breakdown voltage (BDV) after ℃XIHr.

As is clear from Table 1, by adding and mixing a silicone resin and an inorganic photonic agent to a compound obtained by hydrolyzing, dehydrating, and condensing an alkoxide, the film formability after 600°C x lHr, that is, after ceramicization, is improved and the dielectric breakdown voltage is It can be seen that the results are improved.

〔Effect of the invention〕

As shown in the examples, insulated wires in which the paint of the present invention is applied and baked directly onto the conductor or through other insulators have improved dielectric breakdown voltage after ceramicization, and this effect is large enough to be used industrially. Great value.

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Claims (4)

[Claims] (1) General formula R'nM(OR)m (wherein R is an alkyl group, R' is an alkyl group, M is a metal, m is an integer of 1 or more, and n is an integer of 0 or more) 1. A coating composition comprising a compound obtained by hydrolysis and dehydration condensation of an alkoxide represented by the following formula in a solvent, and a silicone resin as an inorganic filler. (2) The coating composition according to claim 1, wherein the silicone resin is modified with polyester. (3) The amount of silicone resin and inorganic filler added is 20 to 200 parts by weight of silicone resin and 20 to 200 parts by weight of inorganic filler per 100 parts by weight of a compound obtained by hydrolyzing and dehydrating an alkoxide in a solvent. The coating composition according to claim 1, characterized in that the amount is 100 parts by weight. (4) An insulated wire, characterized in that the coating composition according to claim 1 is applied and baked onto a conductor directly or via an insulator.