JPH04323264A - Silicone resin composition and heat-resistant insulated wire - Google Patents

Abstract

PURPOSE:To obtain a composition having heat resistance and electrical characteristics as a covering material for insulated wires by blending a specific silicone oil and a silicon-containing compound with an organometallic compound, a polysilane compound, etc. CONSTITUTION:A silicone resin composition is obtained by blending (A) 100 pts.wt. total amount of a silicone oil having at least one of atoms or groups selected from H, halogens, hydroxyl groups and hydrolyzable groups bound to silicon atom in one molecule and a silicon-containing compound containing >=2 silanol groups bound to the silicon atom with (B) 0.1-30 pts.wt. organometallic compound, (C) 20-300 pts.wt. inorganic filler and (D) 3-50 pts.wt. polysilane compound. The group bound to the Si in the component (A) is preferably H or alkoxy and the average molecular weight of the silicone oil is preferably 500-50000.

Description

[Detailed description of the invention]

0001

[Field of Industrial Application] The present invention relates to the improvement of silicone resin compositions, and in particular to the use of this silicone resin composition as a coating material for insulated wires to obtain insulated wires with excellent heat resistance and electrical properties. This is what we do.

0002

BACKGROUND OF THE INVENTION Conventionally, coating materials used for insulated wires requiring heat resistance include radiation-crosslinked resins, fluororesins such as polytetrafluoroethylene, and polyimides. However, the heat resistance of insulated wire coated with fluororesin or polyimide is 250℃ or less in regular use.
Even for a short time, the temperature is at most 300°C or less.

[0003] Recently, equipment used in special environments such as around ships, aircraft, and automobile engines, melting furnaces, and power generation equipment has a heat resistance of 300°C or higher, especially 400°C or higher. Demand for insulated wires has increased. In response to this demand, organic materials mainly having a carbon-carbon skeleton, such as insulated wires coated with polytitanocarbosilane (Japanese Patent Application Laid-Open No. 62-48773), and organic materials mainly having a silicon-oxygen-boron skeleton, etc. Insulated wire coated with material such as polyborosiloxane (Japanese Unexamined Patent Publication No. 63-250012)
has been proposed and has been put into practical use in some cases. These coating materials are characterized by being flexible, turning into ceramic when fired at high temperatures, and having excellent insulation properties.

However, on the other hand, the above-mentioned coating materials have the following drawbacks. That is, all of these coating materials are dissolved in an organic solvent and then applied onto the conductor.
An insulating film is formed by baking, but this organic solvent evaporates during high-temperature baking, creating a large number of pores in the coating layer. Furthermore, when heated to a high temperature of 400° C. or higher, the insulating coating layer shrinks during the process of decomposition or sublimation of organic groups, and also generates minute cracks and voids. For this reason, moisture easily enters through the pores, resulting in a significant decrease in the moisture resistance of the insulating coating layer, resulting in a problem of poor electrical properties as an insulated wire.

[0005]

[Problems to be Solved by the Invention] As a result of extensive research in view of the current situation, the present invention is based on the results of the present invention, in which an insulated wire is made by coating and baking on the outer periphery of a conductor, without using any organic solvent. The coating after baking has excellent flexibility, heat resistance, and moisture resistance, and it suppresses shrinkage of the coating layer even when heated to high temperatures of 400°C or higher, making it a coating material with excellent electrical insulation properties. The present invention aims to provide a silicone resin composition.

[0006]

[Means for Solving the Problems] The invention of claim 1 is directed to at least one atom or group selected from the group consisting of a hydrogen atom, a halogen atom, a hydroxyl group, or a hydrolyzable group bonded to a silicon atom in a molecule. An organometallic compound is added to 100 parts by weight of the total amount of silicone oil (hereinafter referred to as component (A)) and a silicon-containing compound containing two silanol groups bonded to silicon atoms (hereinafter referred to as component (B)). (hereinafter referred to as component (C)) 0.1 to 30.0 parts by weight, inorganic filler (hereinafter referred to as (D) component)
This silicone resin composition is characterized in that 20 to 300 parts by weight of component (hereinafter referred to as component (E)) and 3 to 50 parts by weight of a polysilane compound (hereinafter referred to as component (E)) are added and mixed.

[0007] Furthermore, the invention of claim 2 is a heat-resistant silicone resin composition having an insulating layer formed by applying the silicone resin composition according to the invention of claim 1 onto an electrical conductor directly or via an inorganic insulating layer and baking the silicone resin composition. It is an insulated wire.

[0008]

[Function] The silicone resin composition of the present invention has a hydrogen atom bonded to a silicon atom, a halogen atom,
It is necessary that one or more hydroxyl groups and hydrolyzable groups exist in one molecule. However, as the number of these increases, the degree of crosslinking improves, and the mechanical strength can be improved. Groups other than the above-mentioned hydrogen atom, halogen atom, hydroxyl group, and hydrolyzable group are not particularly limited, and known monovalent hydrocarbon groups can be exemplified. In addition, an alkoxy group, an amino group, and an aminooxy group can be mentioned as a hydrolyzable group. Further, it is preferable that a hydrogen atom or an alkoxy group be bonded to the group bonded to the silicon atom, since the reaction is moderate and handling becomes easy. Furthermore, the average molecular weight of silicone oil is approximately 500.
A range of 50,000 to 50,000 is preferred.

Component (B) acts as a crosslinking agent, and typical examples include organopolysiloxanes such as dimethylpolysiloxane modified with alcohol at both ends, 1,4-bis(hydroxydimethylsilyl)benzene, and diphenyl. Low molecular weight substances such as silane diol can be mentioned.

[0010]The silicone resin composition of the present invention is prepared by first mixing the above components (A) and (B) and subjecting them to a condensation reaction, but there are no particular limitations on the blending ratio. , usually silicone oil 10-90
The silicon-containing compound is 90 to 10% by weight relative to the weight%,
If it is blended outside this range, either heat resistance or flexibility will be emphasized, which is not preferable.

Regarding component (C), component (A) and (B
) It corresponds to a silanol condensation catalyst that acts as a catalyst during the condensation reaction with components. Diisopropoxide ethyl acetoacetate, aluminum di-
One or more of chelate compounds such as Sec-butoxide ethylacetoacetate and metal alkoxides such as tetra-iso-propoxy titanium, tetra-n-butoxy titanium, and tetraethoxy titanium are used.

[0012] Also, as the blending ratio of component (C), the above (
0.00 parts per 100 parts by weight of the total amount of component A) and component (B).
Although the amount is limited to 1 to 30.0 parts by weight, the reason for this is that if it is less than 0.1 part by weight, the condensation reaction between components (A) and (B) will be delayed. If the amount exceeds 30.0 parts by weight, heat may be generated locally or the component (C) itself may be hydrolyzed to become an oxide, which is not preferable.

[0013] Also, as the component (D), for example, Al2 O3
, SiO2, TiO2 and other oxides, BN, AlN
, Si3N4 and other nitrides, and silicate minerals such as mica and talc, and those having a plate-like structure such as mica are particularly preferred.

Regarding the blending ratio of component (D), (A)
20 parts per 100 parts by weight of the total amount of component and (B) component
The reason for this is that if the amount is less than 20 parts by weight, the silicone resin composition of the present invention having the desired height cannot be obtained, and if it exceeds 300 parts by weight, This is because flexibility is inferior.

[0015] Component (E) acts as a crosslinking agent for components (A) and (B) at a high temperature of 400°C, such as polycilastin.

The blending ratio of component (E) is 3 to 5 parts by weight per 100 parts by weight of the total amount of components (A) and (B).
The content is limited to 0 parts by weight, because if it is less than 3 parts by weight, the moisture resistance of the silicone resin composition of the present invention cannot be improved, and if it exceeds 50 parts by weight, mechanical damage may occur. This is because although the strength increases, the flexibility is significantly reduced.

To obtain the silicone resin composition of the present invention, each of the components (B) to (E) is added to the above component (A), and the mixture is thoroughly kneaded and dispersed using a ball mill or three-roll machine. good.

The silicone resin composition of the present invention also has the above-mentioned (
In addition to components A) to (E), ultraviolet absorbers, ozone deterioration inhibitors, light stabilizers, pigments, etc. may be added as necessary.

The silicone resin composition of the present invention is particularly suitable as a coating material for producing insulated wires,
For example, the silicone resin composition of the present invention is coated directly onto an electrical conductor or via an inorganic insulating layer made of other inorganic insulators such as ceramic fibers, wrapped or braided, or wrapped with mica tape, and heated at 250 to 300°C. By performing heating baking to form an electrical insulating layer, a heat-resistant insulated wire with excellent moisture resistance can be obtained.

[0020]

【Example】

[Example (1)]

As shown in Table 1, as component (A), 70 parts by weight of dimethylpolysiloxane (FH0023, manufactured by Chisso Corporation, trade name) having a hydrogen atom and having an average molecular weight of 10,000, and as component (B), 70 parts by weight of dimethylpolysiloxane having an average molecular weight of 10,000, and as component (B), 70 parts by weight of dimethylpolysiloxane having hydrogen atoms and having an average molecular weight of 10,000. Dimethylpolysiloxane (SF8427, Toray, manufactured by Dow Corning Silicone Co., Ltd., trade name) 30 parts by weight total 1
00 parts by weight, 3 parts by weight of titanium octyl glycolate (TOG, manufactured by Nippon Soda Co., Ltd., trade name) as the (C) component, and mica (K-200-825, manufactured by Co-op Chemical Co., Ltd.) as the (D) component. , trade name) 40 parts by weight and (E)
As a component, 10 parts by weight of polycilastin (PSS-120, manufactured by Nippon Soda Co., Ltd., trade name) was blended, and this mixture was kneaded in a ball mill for about 2 hours to obtain a silicone resin composition of the present invention. [Example (2)]

In Example (1), dimethylpolysiloxane having hydrogen atoms (BY
16-805, Toray Dow Corning Silicone (
All examples are Example (1) except that the product manufactured by Co., Ltd., product name) was used.
A silicone resin composition of the present invention was obtained in the same manner as above. [Example (3)]

Titanium alcoholate (B-4
A silicone resin composition of the present invention was obtained in the same manner as in Example 1 except for using Nippon Soda Co., Ltd., trade name). [Example (4)]

[0024] In place of mica as component D in Example 1, A
All examples were as in Example (1) except that 10 parts by weight of 12 O3 (WCA-12, manufactured by Shinano Denkiren Co., Ltd., trade name) was used.
A silicone resin composition of the present invention was obtained in the same manner as above. [Comparative example (1)]

Component (B) in Example (1) was not used, except that component (A) was replaced with 100 parts by weight of dimethylpolysiloxane having a hydrogen atom (FA0023, manufactured by Chisso Corporation, trade name). A comparative silicone resin composition was obtained in the same manner as in Example (1). [Comparative example (2)]

In Example (1), component (A) was not used, but component (B) was replaced with dimethylpolysiloxane (SF8427, Dow Corning Co., Ltd.) modified with alcohol at both ends.
A comparative silicone resin composition was obtained in the same manner as in Example (1) except that 100 parts by weight (trade name, manufactured by Silicone Co., Ltd.) was used. [Comparative Example (3)] A comparative silicone resin composition was obtained in the same manner as in Example (1) except that polycilastin as component (E) was not used in Example (1).

In order to test the performance of the thus obtained silicone resin compositions of the present invention and comparative silicone resin compositions, insulated wires were prepared as follows, and the electrical properties of the insulated wires were measured. The results are shown in Table 1.

That is, as shown in FIG. 1, the silicone resin composition of the present invention and the silicone resin composition of the comparative example
(Silver-plated copper wire with a diameter of 0.4 mm, 7 cores) is coated on the outer periphery of the wire and then baked at approximately 300°C to achieve a coating thickness of 0.15~
An insulated wire having a 0.16 mm insulator layer 2 was produced and its electrical properties were measured. The results are shown in Table 1. [Examples (5) to (8)]

As shown in FIG. 2 similar to the above, a braided insulating layer 3 made of ceramic fiber (quartz glass fiber, manufactured by Asahi Glass Co., Ltd., trade name) is provided on the outside of the stranded conductor 1.
The same silicone resin paint as in Examples (1) to (4) was applied to the outside thereof, and baked at about 300°C to form an insulator layer 2 to prepare an insulated wire, and the electrical properties were measured. The results are shown in Table 1.

[0030]

[Table 1]

[0031]

[Effect of the invention] According to the silicone resin composition of the present invention,
When an insulated wire is obtained by coating and baking an insulating layer on a conductor, there is no need to dissolve the composition in an organic solvent, and the composition can be applied directly as a paint. Therefore, during the baking operation after coating, the solvent does not volatilize and no pores are formed in the insulating layer. Furthermore, it is industrially useful because it suppresses shrinkage of the insulating layer even when heated to high temperatures, becomes ceramic, does not develop minute cracks, does not deteriorate in physical properties, and has excellent electrical properties.

[Brief explanation of drawings]

FIG. 1 is an explanatory cross-sectional view of an example product of a heat-resistant insulated wire of the present invention.

FIG. 2 is an explanatory cross-sectional view of another example of the heat-resistant insulated wire of the present invention.

[Explanation of symbols]

1... Electric conductor, 2... Insulator layer formed by heating and baking a silicone resin composition, 3... Inorganic insulating layer.

Claims (2)

[Claims] Claim 1: A silicone oil containing in one molecule at least one atom or group selected from the group consisting of a hydrogen atom, a halogen atom, a hydroxyl group, or a hydrolyzable group bonded to a silicon atom, and a silicon atom. and a silicon-containing compound containing two or more silanol groups bonded to 100 parts by weight,
Organometallic compound 0.1 to 30.0 parts by weight, inorganic filler 2
A silicone resin composition characterized in that 0 to 300 parts by weight and 3 to 50 parts by weight of a polysilane compound are added and mixed. 2. A heat-resistant insulated wire, characterized in that the silicone resin composition according to claim 1 is coated and baked on an electrical conductor directly or via an inorganic insulating layer.