JPS612208A - Method of producing twisted insulated wire - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION (Technical Field) The present invention relates to b) a method for producing twisted insulated wires used as internal wiring of various electronic devices.

In particular, the present invention relates to a method of manufacturing twisted insulated wires in which an insulating paint is applied and cured to twisted conductors.

(Prior art and its problems) Insulated wires for in-machine wiring used as internal wiring of various electronic devices are made by coating twisted conductors with an insulating material by an extrusion method. Such insulated wires have been used as conductors or as bare wires for shielded wires, coaxial cables, or flat cables.

In recent years, as electronic devices have become smaller and lighter, there has been a trend to make these insulated wires, shielded wires, cables, etc. even thinner. One method is to make the insulating film covering the conductor thinner.

If you line up, it is already 114.783 and 114.783.
7-99314 etc., an example of an insulated wire in which a twisted conductor is coated with an insulating paint has been published. However, when an insulating paint is actually applied and baked on a twisted conductor, the problem of foaming occurs. That is, when an insulating paint is coated and baked on a twisted conductor, air remains in the shaded area shown by 2 in the figure, so the air expands during heating and often causes foaming in the film.

The inventors of the present invention have conducted extensive research and have developed a method that does not cause foaming when forming an insulating film on a twisted conductor, which will be described in detail below.

(Structure of the Invention) The main point of the present invention is to seal the air present in the shaded area inside the twisted conductor by applying and curing a solvent-free radiation-curable paint at least once, and then applying the insulating paint in the subsequent process. The objective is to suppress foaming of the film due to the air expansion during baking.

When forming an insulating film on a twisted conductor by applying and baking an insulating paint, the air on the slope shown in the figure heats and expands.
Foaming occurs because the substance tries to break through the film and come out of the film. For example, air is heated from room temperature (20°C) and
When the temperature reaches 50°C, the volume increase is approximately 1.8 times under constant pressure. In order to prevent foaming due to such an increase in air volume, the present inventors applied a solvent-free radiation-curable paint that basically cures at room temperature with felt, etc. to an appropriate film thickness, and then exposed it to ultraviolet rays or electron beams. Line hardening was performed to seal all the air inside. After that, in order to obtain the desired film thickness and target insulated wire characteristics, a solvent-free radiation-curing paint or a solvent-based heat-curing paint is applied.
hardened. This manufacturing method no longer causes foaming of the coating, and it is possible to obtain twisted insulated wires that can withstand practical use.

The solvent-free radiation-curable paint can be applied to the area 3 in the figure, and conventional methods such as felt or die can be used for painting. The case where the portion 3 in the figure is coated with the radiation-cured paint is not limited to one application, and the application and curing may be repeated multiple times.

After coating the part 3 in the figure with a film thickness that suppresses foaming, apply various solvent-free radiation-cured paints or solvent-based paints using felt, die, etc. coating methods to achieve the desired film thickness and wire characteristics. The coating is then cured by ultraviolet or electron beam irradiation in the case of radiation-curable coatings, or by heating in the case of solvent-based coatings.

Examples of the solvent-free radiation-curable paint used in the present invention include the following.

) Oligomers having an acryloyl group or methacryloyl group at the molecular end, such as ester acrylate oligomer, ester methacrylate oligomer, urethane acrylate oligomer, urethane methacrylate oligomer, epoxy acrylate, epoxy methacrylenide, polyether acrylate, polyether methacrylate-1. , acrylic acid, methacrylic acid, methyl acrylate, methyl methacrylate, ethyl acrylate, ethyl methacrylate, butyl acrylate, butyl methacrylate, and prepolymers of acrylic acid or methacrylic acid derivatives.

(2) Allyl ester oligomers, allyl ether oligomers, allyl urethane oligomers, allyl epoxy oligomers, etc., which have an allyl group at the end of the molecule, diallyl phthalate, triallyl isocyanurate, triallyl cyanurate, etc. An oligomer with an allyl group at the end of the molecule, consisting of a prepolymer of a compound containing

(3) Polyester oligomers, oligoether oligomers, polyurethane oligomers, and epoxy oligomers having an epoxy ring at the molecular end; however, when using an epoxy compound, a Lewis acid as a cationic polymerization catalyst is produced, such as a Lewis acid diazonium salt or a Lewis acid sulfonium salt. It is necessary to add salts such as Lewis acid iodonium salts.

(4) Unsaturated polyester oligomers, unsaturated polyesters, imide oligomers, and unsaturated polyamide oligomers having unsaturated bonds derived from maleic acid, fumaric acid, itaconic acid, etc. in their molecular chains.

(5) Polybutadiene, polythiol, polyene type resin, spiroacecool resin having an unsaturated double bond in the molecular chain or in the side chain.

It is also possible to use a mixture of two or more compounds having two or more types of the above-mentioned F compound structures in the molecular chain or L compound compounds.

Furthermore, among the compounds of (1) to (5) above, methyl acrylate, methyl mechacrylate, ethyl acrylate, ethyl methacrylate, butyl acrylate, butyl methacrylate, ethylene glycol diacrylate, ethylene glycol methacrylate, trimethylolpropane triacrylate, Acrylic esters and methacrylic esters such as trimethylolpropane trimethacrylate, triallylisocyanurate-1-1l
- Compounds with an allyl group such as realyl cyanurate, diallyl tucrate, allyl glycidyl ether, diallylamine, N,N diallyl sevendoamide, styrene,
Known reactive diluents such as divinylbenzene and vinylpyrrolidone can be added.

When curing by irradiation with ultraviolet rays, it is necessary to add a photosensitizer to the above compound. As the photosensitizer, many known sensitizers are used, such as benzoin alkyl ethers such as benzoin ethyl ether and benzoin n-butyl ether, acetophenone derivatives such as jetoxyacetophenone, and aluminum oxime esters.

In the present invention, any commonly used insulating paint such as polyvinyl formal, polyurethane, polyester, polyesterimide, polyamideimide, polyimide, etc. can be used as the solvent-based insulating paint to be applied after solvent-free radiation curing. It is possible.

Further, the material of the stranded conductor used in the present invention may be any commonly used stranded conductor such as copper, and the number of strands making up the stranded wire in the figure is seven. However, it is not limited to this in any way.

Hereinafter, the present invention will be specifically explained using Examples.

(Comparative Example 1) A polyurethane insulating paint (concentration 30%) was applied to a twisted steel wire consisting of 7 wires/0.06 mm using felt and baked (baking temperature 300'' C1 line speed 2 Q m7
/min, the number of times of coating and baking is 12 times). Average 3 per meter
There were ~10 foams. Table 1 shows the characteristics of the insulated wire.

(Comparative Example 2) Polyester insulation (concentration: 1/0) was applied to a twisted steel wire consisting of 7 wires/0.05 mm using felt, and baked (baking temperature: 320″01 line speed: 2Qm) /m
in, the number of times of coating and baking was 12 times). The average number of bubbles per meter was 2 to 7.

Table 1 shows the characteristics of the insulated wire.

(Comparative Example 3) A polyamide-imide insulating paint (concentration 25%) was applied to a twisted steel wire consisting of 7 wires/0.10 mm using felt and baked (baking temperature: 320°C, line speed: 18m/
笥n The number of times of coating and baking is 15 times). The average number of bubbles per meter was 30 to 70. Table 1 shows the characteristics of insulated wires.
Shown below.

(Example 1) Everything is the same as Comparative Example 1 except as described below.

1.5wt of Aronix 6100 (manufactured by Toagosei Co., Ltd., ester acrylate oligomer) as a photosensitizer was added to the twisted conductor.
A solvent-free radiation-curable paint containing Suntray #1000 (manufactured by Mitsubishi Yuka Co., Ltd.) was applied to the polyurethane insulation paint using felt and then baked under the conditions shown in Comparative Example 1. No foaming occurred in the coating, and an insulated wire with a good appearance was obtained. Table 1 shows the characteristics of the insulated wire.

(Example 2) Everything is the same as Comparative Example 2 except as described below.

Mix VR, -ri0 (manufactured by Showa Kobunshi Co., Ltd., epoxy acrylate oligomer) and Aronix a1om (manufactured by Toagosei Co., Ltd., ester acrylate oligomer) at a ratio of 1:1 to the twisted conductor, and apply it using felt and then irradiate it with an electron beam. It was cured by irradiation with a dose of 7 Mrad in a nitrogen gas atmosphere using a device (1 pull, line speed 20 m/mi).
n). Thereafter, a polyester insulation paint was applied and baked under the conditions shown in Comparative Example 2.

No foaming occurred in the coating, and an insulated wire with a good appearance was obtained.

Table 1 shows the characteristics of the insulated wire.

(Example 3) Everything is the same as Comparative Example 3 except as described below.

A solvent-free radiation-curing paint made of ultraviolet F-1J curing epoxy resin (Azoca Ultraset manufactured by Asahi Denka Co., Ltd.) and 1.5W1% Suntore #1000 (manufactured by Mitsubishi Yuka Co., Ltd.) as a photosensitizer for the twisted conductor. was applied using felt and cured by ultraviolet irradiation (one pull, ultraviolet lamp 3 kW, line speed 9 Qm/min). Thereafter, under the conditions shown in Comparative Example 3,
Polyamide-imide insulation paint was applied and baked. No foaming occurred in the coating, and an insulated wire with a good appearance was obtained. Table 1 shows the characteristics of the insulated wire.

Table 1 Characteristics Note that the characteristics were determined according to JIS C3003.

[Brief explanation of drawings]

This figure shows a cross-sectional view of a twisted insulated wire manufactured by the manufacturing method according to the present invention. 1. Twisted conductor 2. Gaps between the stranded conductors 3. Insulating coating between the stranded wires (solvent-free radiation curing paint) 4. Insulating coating

Claims (2)

[Claims] (1) A method for manufacturing twisted insulated wires, which comprises applying a solvent-free insulating paint to a twisted conductor and curing it, and then applying and baking a solvent-based insulating paint as necessary. (2) A method for manufacturing a twisted insulated wire according to claim 1, characterized in that an ultraviolet or electron beam irradiation cured paint is used as the solvent-free insulating paint.