JP3090352B2 - Manufacturing method of tape wound insulated wire - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for manufacturing a polyimide tape insulated wire having high heat resistance and having no adhesive layer.

[0002]

2. Description of the Related Art Conventional insulated wires for high heat resistance are produced by winding a commercially available polyimide tape such as a Kapton (made by Toray DuPont) film with a fluororesin adhesive or the like around the core wire and firing it. It is manufactured by directly immersing the core wire in a polyamic acid varnish that is a precursor of polyimide, and then heating and drying and imidizing it.However, the former is not sufficient in heat resistance because it uses a fluororesin or the like as an adhesive. In the latter, it is difficult to arbitrarily control the thickness of the polyimide layer because the core is immersed in the varnish.

[0003]

SUMMARY OF THE INVENTION An object of the present invention is to make use of the inherent alkali resistance, solvent resistance, heat resistance, and electrical properties of polyimide as it is, and to obtain excellent properties by winding a stretched tape. An object of the present invention is to provide a method for producing a polyimide tape wound insulated wire without an adhesive layer having film properties.

[0004]

According to the present invention, there is provided a tape winding method comprising: winding a polyamic acid tape which has been stretched by 10% or more at a specific temperature and tension in advance, around a core wire, and heating and drying to imidize the tape. This is a method for manufacturing an insulated wire.

That is, a polyamic acid solution is applied on a release film or a release drum, and dried until a tack-free state is obtained, thereby forming a polyamic acid film. Thereafter, the film is peeled from the release film or the release drum, and only the amic acid film is stretched by 10% or more under a specific temperature and tension, and then slit into a predetermined width to obtain a polyamic acid tape. Although the magnitude of the effect varies depending on the type of polyimide, stretching by 10% or more generally improves film properties such as tensile strength and elastic modulus. After winding the tape around the core wire, the tape is sufficiently heated and dried to perform imidization.

In the present invention, the conditions for drying the polyamic acid solution to form a semi-cured polyamic acid film are not limited as long as the film is tack-free and there is no problem in workability. 5 to 30 minutes is appropriate. If the temperature is lower than this, and the time is short, the amount of the residual solvent remaining in the film is large, and the variation in the coating thickness becomes large, and it is difficult to control the thickness to a predetermined value. On the other hand, when the temperature is higher than this, the imidization proceeds too much, the fluidity of the film is lost, and the adhesion to the core wire and the adhesion between the films become insufficient.

In the present invention, the specific temperature and tension vary depending on the type of polyamic acid, but the conditions under which the polyamic acid film can be stretched by 10% or more within the temperature range suitable for drying the semi-cured polyamic acid film. Is not particularly limited.

The polyamic acid of the present invention is usually obtained by reacting a diamine with an acid anhydride.
Examples of the diamine include phenylenediamine, diaminodiphenylmethane, diaminodiphenylsulfone, and diaminodiphenylether.Examples of the acid anhydride include trimellitic anhydride, pyromellitic dianhydride, biphenyltetracarboxylic dianhydride, and benzophenonetetracarboxylic acid. Dianhydrides and the like can be used.
Species or a combination of two or more can be used as appropriate. The imidation ratio in the state of the polyamic acid film is preferably from 10 to 50%, and more preferably from 20 to 40%. If the imidization ratio is less than 10%, not only the tackiness remains and the workability is poor, but also after winding, it is difficult to isolate the films one by one by adhering to the back of the release film, and more than 50% imidization. Is applied, the melting property is deteriorated, and even if the amic acid surfaces are combined and thermocompression-bonded, they are not sufficiently integrated.

Materials that can be used as the release film include plastic films such as polypropylene, polyester, polyethersulfone, polyimide, and polyethylene.

Materials that can be used for the conductor core include metal cores such as copper, aluminum, constantan, and nickel.

[0011]

According to the present invention, the polyamic acid film is easily formed by wrapping a pre-stretched polyamic acid tape around the outer periphery of the core wire and heating and drying to imidize, utilizing the easy moldability and mechanical strength of the polyamic acid film. With good productivity and yield, the original alkali resistance, solvent resistance, heat resistance, and electrical properties of polyimide are utilized as they are, and the mechanical properties are further improved by stretching. A polyimide tape wound insulated wire can be obtained.

[0012]

EXAMPLE A 4-neck separable flask equipped with a thermometer, a stirrer, a reflux condenser and a dry nitrogen gas inlet was charged with 108 g of purified anhydrous paraphenylenediamine and 4,
Take 200 g of 4'-diaminodiphenyl ether, add a mixed solvent of 90% by weight of anhydrous N-methyl-2-pyrrolidone and 10% by weight of toluene to a solid content ratio of 20% by weight in all the raw materials.
Was added and dissolved. Dry nitrogen gas was allowed to flow throughout the entire process from the preparation of the reaction to the removal of the product. Next, 294 g of purified anhydrous 3,3 ', 4,4'-biphenyltetracarboxylic dianhydride and 218 g of pyromellitic dianhydride are added little by little with stirring, but the reaction is exothermic. This was cooled by circulating cold water at about 15 ° C. After the addition, set the internal temperature to 20 ° C,
After stirring for 5 hours, the reaction was completed to obtain a polyamic acid solution.

This polyamic acid solution was applied on a stainless steel drum with a bar coater so that the thickness after imidization became 50 μm, dried at 110 ° C. for 15 minutes, peeled from the drum, and peeled at 110 ° C. at 2 kg / kg. A tension of cm was applied to obtain a 40% stretched polyamic acid film. This film was slit into a width of 20 mm using a slitter to obtain a polyamic acid tape. After winding this tape three times on the core wire, it was heated and dried at 380 ° C. for 1 hour and imidized to obtain a polyimide tape wound insulated wire. The properties of the obtained tape wound insulated wire were excellent heat resistance (solder heat resistance, 360 ° C., 1 minute) and chemical resistance inherent to polyimide.

[0014]

According to the present invention, it is possible to obtain a tape-wound insulated wire composed of only a polyimide layer having no adhesive layer and having excellent film properties. It is suitable as an industrial method for manufacturing a tape-wound insulated wire because it can be easily applied to the continuous process used.

Continuation of the front page (58) Field surveyed (Int.Cl. ⁷ , DB name) H01B 13/08-13/10 H01B 13/26 H01B 3/16-3/56 H01B 7/00-7/02

Claims (1)

(57) [Claims] 1. A method for producing a tape-wound insulated wire, comprising winding a polyamic acid tape stretched by 10% or more around the core wire and heating and drying imidization.