JPH061847A - Silicone resin composition and heat resistant insulated wire - Google Patents

Abstract

(57) [Abstract] [Purpose] A silicone resin composition that can be applied onto a conductor without being dissolved in an organic solvent and that provides an insulating coating layer that exhibits excellent moisture resistance and heat resistance even after baking,
And a heat resistant electric wire using the same. [Structure] A chain silicone oligomer having at least two or more reactive groups in one molecule and M (OR) _n (wherein M represents a silicon atom or a metal atom, R represents an alkyl group or an alkoxy group, n is a natural number of 2 to 4) and 80:20 to 2 with an organic compound represented by
100 parts by weight of mixture in the range of 0:80, inorganic filler 2
A silicone resin composition obtained by reacting a mixture containing 0 to 300 parts by weight and 0.01 to 25 parts by weight of a metal oxide sol at 60 to 90 ° C. The heat resistant insulated wire is produced by applying the resin composition on the circumferential surface of the stranded wire conductor to a predetermined thickness and then baking the resin composition to provide a heat resistant insulating layer.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a silicone resin composition and a heat resistant insulated wire using the same.

[0002]

2. Description of the Related Art Conventionally, a fluorine resin such as polytetrafluoroethylene or a polyimide resin has been used for an insulated wire which is required to have heat resistance. These organic coating materials are mainly composed of a carbon-carbon skeleton, and the heat resistance of the insulated electric wire coated with them is 250 ° C. or less in normal use.
Even if it is used for a short time, the limit is 300 ° C.

However, in the case of equipment used in special environments such as ships, aircraft, automobile engines, blast furnaces, power generation facilities and the like, heat resistance exceeding 300 ° C., particularly preferably 400 ° C. or more. A heat resistant electric wire having properties is desired.

In response to such a demand, polytitanocarbosilane having a carbon-silicon-titanium skeleton as a main component, in place of the above-mentioned organic coating material having a carbon-carbon skeleton as a main component,
A coating material such as polyborosiloxane mainly composed of a silicon-oxygen-boron skeleton has been proposed. Insulated electric wires using these are disclosed in JP-A-62-48773 and JP-A-60-
It is disclosed in Japanese Patent No. 250012, etc., and is partially put into practical use. These coating materials have excellent flexibility, and when they are baked on a conductor at a high temperature, they become ceramics and exhibit heat resistance, and also have excellent electrical insulation.

[0005]

However, all of the above-mentioned heat-resistant coating materials have relatively high viscosities, and therefore, when applied on a conductor, they must be dissolved in an organic solvent to obtain an appropriate viscosity. However, various problems occur due to this organic solvent.

In producing an insulated wire, an insulating coating layer is formed by applying a heat resistant coating material on a conductor and then baking it. At this time, the organic solvent volatilizes and the insulating coating layer is formed. A large number of holes are formed inside.

When the insulated wire is used in a high temperature atmosphere of 400 ° C. or higher, shrinkage occurs in the insulating coating layer in the process of decomposition or sublimation of the organic groups in the composition, resulting in fine cracks and voids. To do. Furthermore, since the adhesion with the conductor is reduced and a gap is created between the conductor and the insulating coating layer, moisture easily enters through these holes and the like, and the moisture resistance of the insulating coating layer is significantly reduced. However, there is a problem in that the electric characteristics of the insulated wire are significantly deteriorated.

Therefore, the present invention provides a silicone resin composition which can be applied onto a conductor without being dissolved in an organic solvent and provides an insulating coating layer exhibiting excellent moisture resistance and heat resistance even after baking, Another object of the present invention is to provide a heat resistant electric wire using the same.

[0009]

In order to solve the above-mentioned problems, the first aspect of the invention is to provide a chain silicone oligomer having at least two or more reactive groups in one molecule, and M
(OR) _n (wherein M represents a silicon atom or a metal atom, R represents an alkyl group or an alkoxy group, and n represents 2 to 4).
Is a natural number of. 80: 2 with an organic compound represented by
A mixture containing 100 parts by weight of the mixture in the range of 0 to 20:80, 20 to 300 parts by weight of the inorganic filler, and 0.01 to 25 parts by weight of the metal oxide sol at 60 to 90 ° C. A silicone resin composition is provided.

Further, a second aspect of the present invention is characterized in that the silicone resin composition of the above-mentioned first aspect of the invention is applied to a conductor directly or through an inorganic insulating layer and baked. Provided is a heat resistant insulated electric wire.

The present invention will be described in more detail below.

The silicone resin composition according to the first aspect of the present invention is a crosslinking reaction product of the following components.

(A) Chain silicone oligomer having at least two or more reactive groups in one molecule (B) M (OR) _n (wherein M is a silicon atom or a metal atom, R is an alkyl group or an alkoxy group) Group, n is 2
Is a natural number from 4 to 4. (C) Inorganic filler (D) Metal oxide sol If the molecular weight of the component (A) is less than 1000, the reaction takes a long time, while on the other hand, if it has a high molecular weight of more than 10,000. If so, the viscosity of the resin composition obtained after the reaction becomes too high, so that the viscosity is preferably in the range of 1,000 to 10,000.

Examples of the reactive group in the component (A) include a hydrogen atom, a halogen atom, a hydroxyl group, and a hydrolyzable group, and the hydroxyl group is particularly preferable.
Further, the larger the number of the reactive groups, the higher the degree of crosslinking in the resulting reaction product, and the higher the mechanical strength of the finally obtained insulating coating layer, which is preferable.

Examples of the component (A) used in the present invention include OH group-modified dimethylsiloxane having both terminals, H group-modified dimethylsiloxane having both terminals and side chain H group-modified dimethylsiloxane.

The component (B) mainly acts as a crosslinking agent. Examples of M include titanium, zirconium, and the like. However, since the Ti—Si—O bond has the highest heat resistance, it is most preferable to use titanium.

R forms an alkoxide and a chelate compound together with M. The shorter the number of carbon atoms, the faster the reaction rate, but it is easy to prepare those having 8 or less carbon atoms.

Examples of the component (B) include titanium octylene glycol, tetraethoxysilane, di-n-butoxybis (triethanolaminato) titanium, tetra-n-butoxytitanium and zirconium isopropoxide.

The mixing ratio of the component (A) and the component (B) is
The range of 80:20 to 20:80 is preferable, and when flexibility is required for the insulating coating layer obtained by baking the obtained silicone resin composition, the ratio of the component (A) is increased to When mechanical strength is required, it is possible to obtain an insulating coating layer having desired characteristics by increasing the ratio of the component (B).

As the component (C), for example, Al
₂ O ₃ , oxides such as SiO ₂ , TiO ₂ , BN, Al
Nitride such as N and Si ₃ N ₄ , powder of silicate mineral such as mica and talc can be used, but mica having a plate-like structure is particularly preferable.

The blending amount of the component (C) is 20 to 30 relative to 100 parts by weight of the total amount of the above components (A) and (B).
It is in the range of 0 parts by weight, and if it is less than 20 parts by weight, sufficient hardness cannot be given to the insulation coating layer formed by baking the obtained resin composition, while if it exceeds 300 parts by weight. , The flexibility of the formed insulating coating layer becomes poor.

The component (D) mainly acts as a paint adjusting agent and a film forming agent, and titania sol, alumina sol, silica sol and the like can be used. Note that these components (D) are preferably used as an acidic solution such as a hydrochloric acid-based, acetic acid-based or nitric acid-based solution in order to stably disperse them. The content of the component (D) is 0.01 to 100 parts by weight of the total amount of the components (A) and (B).
It is within the range of 25 parts by weight. When the amount is less than 0.01 parts by weight, sufficient viscosity cannot be obtained. On the other hand, when the amount is more than 25 parts by weight, the composition obtained has a high viscosity and requires dilution with an organic solvent.

The mixture of the components (A) and (B) is mixed with the components (C) and (D), and the mixture is reacted at a temperature within the range of 60 ° C to 90 ° C to obtain the organic component (B). The compound crosslinks the chain silicone oligomer of component (A) to give a high molecular weight, and the composition of the present invention is obtained. If the reaction temperature is less than 60 ° C, the viscosity of the obtained silicone resin composition is too low to be applied to the conductor, because crosslinking is not sufficiently performed, while if it exceeds 90 ° C, the oligomeric composition of Since the crosslinking proceeds too much, the viscosity becomes high.

A heat-resistant insulated electric wire according to a second aspect of the present invention is 300 to 400 ° C. after the silicone resin composition of the first aspect of the present invention is directly applied onto, for example, the peripheral surface of a stranded wire conductor.
It can be obtained by baking with an insulating coating layer, and further, for example, the inorganic insulating layer is formed by winding horizontal winding or braiding of ceramic fiber or mica tape on the peripheral surface of the stranded wire conductor, It is also possible to obtain the composition by applying the composition to the above and baking the same as above.

[0025]

The silicone resin composition of the present invention comprises a chain silicone oligomer, Si-O-Si, as a main chain and M-O.
-Si-O is cross-linked by a cross-linked chain. The inorganic filler has a function as an aggregate and the metal oxide sol has a function as a binder, and can give the resin composition an appropriate viscosity within the range of 100 to 5000 centipoise. Therefore, the silicone resin composition of the present invention can be applied on a conductor without being dissolved in an organic solvent.

Therefore, voids due to volatilization of the organic solvent do not occur during baking. Further, since the insulating coating layer does not shrink in the process of decomposing or sublimating the organic group in the composition, cracks or voids do not occur in the insulating coating layer. Therefore, an air gap does not occur between the conductor and the insulating coating layer, and an insulated wire having moisture resistance and excellent electrical characteristics can be obtained.

Further, by interposing the inorganic insulating layer between the conductor and the insulating coating layer, it is possible to obtain a heat resistant insulated electric wire having further excellent heat resistance and flexibility.

[0028]

EXAMPLES The present invention will be described in more detail below by showing Examples of the present invention.

(Example 1) As the component (A), both ends O
H group modified dimethyl siloxane ((molecular weight 2000) BY
16-817, Toray Dow Corning Silicone Co., Ltd.
Titanium octylene glycol coat (TOG, manufactured by Nippon Soda Co., Ltd.) as component (B), mica (MK100, manufactured by Corp Chemical Co., Ltd.) as component (C), component (D)
As the titania sol (CS-C, manufactured by Ishihara Sangyo Co., Ltd.) was used. 65 parts by weight of the component (A), 35 parts by weight of the component (B), 30 parts by weight of the component (C), and 0.05 parts by weight of the component (D) are mixed and reacted at about 80 ° C. for 30 minutes to give a silicone. A resin composition was obtained.

The viscosity of the resulting composition was 900 centipoise.

Further, the composition thus obtained is applied to the peripheral surface of a stranded wire conductor (diameter 0.4 mm, silver-plated copper wire, 7 cores) in a predetermined thickness, and then baked at about 350 ° C. for insulation coating. Layers were formed to produce a heat resistant insulated wire.

(Example 2) As the component (A), dimethylsiloxane having a hydrogen atom as a reactive group ((molecular weight 40
00) BY16-801, manufactured by Toray Dow Corning Silicone Co., Ltd. was used to prepare a silicone resin composition in the same manner as in Example 1.

The viscosity of the resulting composition was 1000 centipoise.

This composition was applied on the peripheral surface of the same stranded wire conductor as in Example 1 to a predetermined thickness and then baked at the same temperature to produce a heat resistant insulated wire.

(Example 3) A silicone resin composition was prepared in the same manner as in Example 1 except that silicon alcoholate (TEOS, manufactured by ADEKA CORPORATION) was used as the component (B).

The viscosity of the resulting composition was 900 centipoise.

This composition was applied on the peripheral surface of a stranded conductor similar to that of Example 1 to a predetermined thickness and then baked at the same temperature to produce a heat resistant insulated wire.

Example 4 A silicone resin composition was prepared in the same manner as in Example 1 except that alumina (WCA-12, manufactured by Shinano Denki Smelting Co., Ltd.) was used as the component (C).

The viscosity of the resulting composition was 1000 centipoise.

This composition was applied on the peripheral surface of the same stranded wire conductor as in Example 1 to a predetermined thickness and then baked at the same temperature to produce a heat resistant insulated wire.

Example 5 As component (A), dimethyl siloxane ((molecular weight 2000) PRX413, manufactured by Toray Dow Corning Silicone Co., Ltd.) having an OH group as a reactive group and a component ( A silicone resin composition was produced in the same manner as in Example 1 except that alumina sol (Alumina sol 200, manufactured by Nissan Chemical Industries, Ltd.) was used as D).

The viscosity of the resulting composition was 1100 centipoise.

This composition was applied on the peripheral surface of a stranded conductor similar to that in Example 1 to a predetermined thickness and then baked at the same temperature to produce a heat resistant insulated wire.

(Example 6) The composition obtained in Example 1 was used as a stranded conductor similar to that of Example 1 through an inorganic insulating layer made of ceramic fibers (Nextel, 3M Co., Ltd.). After applying a predetermined thickness on the peripheral surface, it was baked at the same temperature to produce a heat resistant coated electric wire.

Example 7 An insulated wire was produced in the same manner as in Example 6 except that high silicic acid fiber (quartz fiber, manufactured by Asahi Glass Co., Ltd.) was used as the inorganic insulator.

(Comparative Example 1) Component (A) was not added, 100 parts by weight of silicon alcoholate (TEOS, manufactured by ADEKA CORPORATION) as component (B), and mica (MK) as component (C).
100 parts by weight of Cope Chemical Co., Ltd.) and 0.1 parts by weight of titania sol (CS-C, manufactured by Ishihara Sangyo Co., Ltd.) are mixed and reacted at about 80 ° C. for 30 minutes to give a silicone composition. It was made.

The obtained composition was applied on the peripheral surface of a stranded conductor similar to that of Example 1 to a predetermined thickness and then baked at the same temperature to produce a heat resistant insulated electric wire.

(Comparative Example 2) Polyborosiloxane resin 10
50 parts by weight of mica (MK100, manufactured by Co-op Chemical Co., Ltd.) as component (C) and 0 parts by weight of toluene as an organic solvent were mixed to obtain a coating composition.

The obtained composition was applied on the peripheral surface of a stranded conductor similar to that of Example 1 to a predetermined thickness and then baked at the same temperature to produce a heat resistant insulated wire.

The compositions of the silicone resin compositions obtained in Examples 1 to 7 and Comparative Examples 1 and 2 and the presence or absence of the use of the organic solvent are summarized in Table 1 below.

Next, with respect to each of the insulated wires obtained in Examples 1 to 7 and Comparative Examples 1 and 2, the state of the insulating coating layer before and after heating at 600 ° C. for 2 hours, the insulation resistance and the breakdown voltage were examined. The results are summarized in Table 2 below, together with the presence or absence of the inorganic insulating layer and the thickness of the insulating layer.

[0052]

[Table 1]

[Table 2] As is clear from Table 2, the insulated wire of the present invention (Example 1
In each of Examples 7 to 7, the state of the insulating coating layer was good before and after heating. No significant difference was observed in the insulation resistance and the breakdown voltage. On the other hand, in the case of the electric wire of Comparative Example 1, cracks were generated in the insulating coating layer after heating, it was not maintained as the insulating coating layer, and the insulation resistance and breakdown voltage could not be measured.

Also in the case of the electric wire of Comparative Example 2, a large number of holes due to the volatilization of the organic solvent were recognized in the insulating coating layer, and fine cracks and voids were also generated. Furthermore, the adhesiveness with the stranded wire conductor was reduced and voids were generated, and it was impossible to measure the insulation resistance and the breakdown voltage, like the electric wire of Comparative Example 1.

[0054]

As described above in detail, since the silicone resin composition of the present invention can be easily applied as it is to a conductor without being dissolved in an organic solvent, it is possible to prepare an insulated wire by using the same. Generation of voids in the insulating coating layer due to volatilization of the organic solvent during baking and shrinkage of the insulating coating layer during use in a high temperature atmosphere can be suppressed. Further, the heat-resistant insulated wire obtained using the silicone resin composition of the present invention can maintain excellent electrical characteristics even under high temperature conditions.

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Claims (2)

[Claims] 1. A chain silicone oligomer having at least two reactive groups in one molecule and M (OR) _n
(Wherein M represents a silicon atom or a metal atom, R represents an alkyl group or an alkoxy group, and n is a natural number of 2 to 4) and 80:20 to 2
100 parts by weight of mixture in the range of 0:80, inorganic filler 2
A silicone resin composition, which is obtained by reacting a mixture containing 0 to 300 parts by weight and 0.01 to 25 parts by weight of a metal oxide sol at 60 to 90 ° C. 2. A heat-resistant insulated wire, which is obtained by applying and baking the silicone resin composition according to claim 1 on a conductor directly or via an inorganic insulating layer.