JPS60151910A - Method of producing flat polyurethane 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 The present invention relates to a method for producing a novel rectangular polyurethane insulated wire.

Flat insulated wire is used for voice coils of speakers and stator coils of cabin motors for VTRs, etc., and has a better space factor than round wire, so it satisfies the requirements for light, thin, short and small wires.
Its uses are also increasing year by year. There are two methods for manufacturing rectangular insulated wires: one is to roll a round wire to form a rectangular conductor, and the other is to apply and bake an insulating face on the outside of the conductor according to a conventional method, and the other is to apply and bake an insulating face on the outside of the conductor. There is a method of rolling it to transform it into a rectangular insulated wire. However, these rectangular insulated wires manufactured by conventional methods have the following drawbacks. That is, in the former case, it is difficult to obtain a coating film with a uniform thickness, and the coating film is particularly thin at the corners, and the conductor surface at the corners is exposed, causing poor insulation. In the latter case, the ratio of the width to the thickness of the flat wire cannot be increased (approximately 1:2 to 2.5), and the thermal shock resistance of the flat wire after rolling is poor, especially for the above-mentioned applications. It was unsuitable for winding wires. As a manufacturing method for rectangular wire that improves these drawbacks, the method described in Japanese Patent Publication No. 49-7428 has been proposed, but the insulating film used therein is made of polyamideimide, polyimide, polyhydantoin,
These materials are limited to highly heat-resistant insulating materials such as polyesterimide, but since none of them have solderability to the insulating film, it is necessary to mechanically remove the insulating film when soldering the ends of the coil.
It has the disadvantage that it must be removed by chemical means,
In particular, in the case of thin rectangular wires obtained by rolling round wires with a conductor diameter of about 0.1, the end treatment of the coils becomes extremely complicated, which poses a major obstacle to automation of the production line.

The present invention has succeeded in obtaining a rectangular polyurethane insulated wire that improves the above-mentioned drawbacks by studying the resin composition of the insulating face in a method of rolling a round grooved enameled insulated wire to obtain a rectangular insulated wire. This will be explained in detail below.

The brazing properties and heat resistance properties of polyurethane insulated wires are in a trade-off relationship; improving one will impede the other, and the adhesion between the conductor and the insulation film depends on the heat resistance of the insulation film used. , for example, polyurethane, polyester, polyesterimide, etc., the higher the price, the higher the
Thermal shock resistance is also improved. Therefore, there is a limit to the improvement of properties when conventionally used general polyisocyanate block compounds are used as crosslinking components. Therefore, in the present invention, a novel polyisocyanate block compound is synthesized, and this is combined with an oligomer or prepolymer having activated hydrogen. A polyurethane insulating paint made by dissolving in an organic solvent is coated on the round groove body, baked, and then rolled to have solderability.
Moreover, it is possible to provide a rectangular polyurethane insulation wire with a large ratio of thickness to width.

The novel isocyanate crosslinking agent developed by the present inventors is a diincyanate block product in which a diol having a spiroacetal ring and a diisocyanate compound are reacted, and the remaining incyanate groups are blocked with a phenolic compound. Specifically, a diol having a spiroacetal ring has a spiroacecool ring as its backbone and alcoholic hydroxyl groups at both terminals, so it easily reacts with a diisocyanate compound to form a urethane bond. This reaction is carried out with an excess amount of diisocyanate, and the diisocyanate block which is stabilized by blocking the remaining isocyanate groups with a phenol compound is difunctional and has a very large molecular chain compared to the conventional diisocyanate block. long.

Examples of the present invention are shown below.

Synthesis Example: Synthesis of spiroacetal-modified diphenylmethane diisocyanate block crosslinking agent In a 4-hole separable flask with a temperature side, a stirrer, a cooling tube, a separating funnel, and a nitrogen gas introduction hole, 91.2% (0.3 mol) of spiroacetal glycol was added. , Kijirol s 06fi' as a reaction diluent and 0.8 t of triethylamine as a catalyst are weighed and added, and stirred thoroughly to uniformly disperse them. Then, in a separatory funnel, 150 ml of diphenylmethane diisocyanate, which had been weighed and heated to 45°C, was added. (
0.6 mol) was gradually added dropwise to react with the spiroacetal glycol. At this time, the temperature of the reaction system rises to about 50-60°C. During this time, stir thoroughly. When the temperature of the reaction system returns to room temperature, 64.8f of m-cresol is further added to block the remaining isocyanate groups, and the infrared absorption band 224 of incyanate is
Stirring is continued until it is confirmed that 0J' is gone.

When the reaction was completed, m-cresol 408F was added so that the solid content of the reaction system was 30% to obtain a solution of spiroacecool-modified diphenylmethane diisocyanate cresol block compound.

Production of rectangular polyurethane insulated wire A solution of 500 fI of the spiroacetal-modified diisocyanate compound obtained according to the synthesis example was used to determine the molecular weight of the polyurethane insulated wire having an alcoholic hydroxyl group. +000 epoxy prepolymer 94fI- was weighed and added and dissolved in a mixed solvent of cresol and Kijirol to give a resin concentration of 50%.A polyurethane insulating paint was prepared on a conductor with a diameter of 0°222 to 0.000°.
The coating thickness is 1050-10 on the annealed copper wire of 295111B.
．． Furnace temperature: 400°C, Linear speed: s 2 m/
A polyurethane insulated wire was manufactured by baking at 10 min. Next, this was rolled in a 4-axis rolling mill with a roll diameter of 25 to obtain a rectangular polyurethane insulated wire according to the present invention.

The properties of the rectangular polyurethane insulated wire of the example are shown in the table below. The comparative example shown is a general-purpose polyisocyanate compound such as coronate, which is a crosslinking agent made by reacting toluene diisocyanate with trimethylolpropane and blocking the remaining incyanate groups with phenol.
Characteristics of a rectangular polyurethane insulated wire made by applying and baking a conventional polyurethane paint using Stipple (trade name of Nippon Polyurethane Co., Ltd.) and an epoxy prepolymer with a molecular weight of 3000 as the polyol component onto the conductor, and then rolling it. It is.

The rectangular polyurethane insulated wire obtained by the manufacturing method of the present invention uses a block incyanate compound having a bulky spiroacecool ring with a long molecular chain as a crosslinking component of the polyurethane sheath JTh, so that the crosslink interval is small. The structure becomes longer and the film deforms relatively easily in response to external stress. Therefore, the adhesion between the conductor and the insulating film is good, the film can sufficiently follow the deformation of the conductor, and the stress strain in the film is small. Conventionally, the thickness and width ratio of the rectangular wire is 1:2.5 or more. However, in the present invention, as seen in the results of the examples, the properties of the film can be maintained even when used as an ultra-thin rectangular wire. Furthermore, since the film has a three-dimensional network structure formed by urethane bonding, it has solderability and can improve the working efficiency of the coil end portion.

The reaction equivalent ratio of the isocyanate groups of the block incyanate crosslinking agent and the hydroxyl groups of the prepolymer having activated hydrogen atoms was limited to a ratio of 1:0.7 to 2.5 because
If it deviates from this range, the crosslinking reaction will be insufficient and the insulating film will become thermally and mechanically brittle.

As explained above, it is significant that a rectangular polyurethane wire with solderability and a large thickness-to-width ratio was obtained according to the present invention, and the present invention greatly contributes to industry.

Applicant Tokyo Special Electric Wire Co., Ltd. Representative: Kogure Tsugu;

Claims (1)

[Claims] A blocked isocyanate obtained by a reaction between a diol having a spiroacecool ring and a diisocyanate compound is used as a crosslinking component, and a prepolymer having an activated hydrogen atom is added to this as a crosslinking component, and the isocyanate group of the blocked incyanate crosslinking agent and the above prepolymer are combined. After applying and baking an insulating paint prepared by adding the insulating paint with the hydroxyl group at a reaction equivalent ratio of 1:0.7 to 2.5 and dissolving it in an organic solvent,
A method for producing a rectangular polyurethane insulated wire, which comprises rolling it into a rectangular shape.