JPS62167385A - Production of surface heating element - Google Patents

Abstract

PURPOSE:To obtain surface heating element free from ply separation, by impregnating glass cloth with a specific rubber solution to form a sheet heating element, laminating an ultraviolet-curing rubber sheet to the two sides of the sheet heating element and irradiating the sheet with ultraviolet rays to bond them completely. CONSTITUTION:Glass cloth is impregnated and coated with a rubber solution blended with electrically-conductive carbon black or graphite to form a sheet heating element. Then, an ultraviolet-curing rubber sheet [preferably one obtained by blending rubber such as chlorosulfonated polyethylene, etc., with a (meth)acrylic acid ester and a photopolymerization initiator and rolling the blend into a sheet, etc.,] is laminated to the two sides of the heating element, the two sides of the rubber sheet are irradiated with 1,200ml/cm<2> ultraviolet rays, respectively and the rubber sheet is cured to give the aimed heating element as a completely bonded, molded article.

Description

[Detailed description of the invention] (Industrial application field) The present invention relates to a method for manufacturing a planar heating element.

(Prior art) Conventional planar heating elements are made by forming a sheet of electrically conductive carbon black or graphite as a heating element using synthetic resin or rubber as a carrier, and then covering the front and back with insulating sheets made of plastic film, rubber, etc. Laminated products are known.

In the method of manufacturing such a planar heating element, a heating element sheet is prepared by kneading conductive carbon black or graphite as a heating element into a synthetic resin or rubber, and then rolling the mixture. Next, the front and back sides of the heating element sheet are laminated with insulating sheets, and at this time, a plastic film such as polyester/%/film, vulcanized rubber, or unvulcanized rubber is used as the insulator, and these are bonded or compressed. The company was manufacturing heating elements.

(Problems to be Solved by the Invention) However, according to this method, the manufactured sheet heating element is made by kneading conductive carbon black or graphite as a heating element element with synthetic resin or rubber and rolling it into a sheet shape. Because of this, when rolled into a sheet, there is directionality due to molecular orientation, and it is also quite difficult to uniformly disperse carbon black and graphite without leaving any mechanical distortion through kneading. However, if the kneading is uneven, there is a problem in that when electricity is applied to the heating element, it causes uneven temperature or even local temperature rise.

In addition, if a plastic film such as a polyester film is used when laminating insulating sheets on the front and back sides of a heating element sheet, it is necessary to use an adhesive or press the film at a high temperature close to the softening temperature of the film. Therefore, depending on the crimping conditions, the laminate could become uneven.

Furthermore, when laminating vulcanized rubber sheets on the front and back, the adhesive used has problems with adhesive strength, heat resistance, durability, etc., and when laminating unvulcanized rubber sheets, a vulcanization process at high temperature and high pressure is required. It had the problem of being indispensable.

(Means for Solving the Problems) The present invention has been made to solve these conventional problems, and involves impregnating glass cloth with a rubber solution mixed with conductive carbon black or graphite. A sheet-like heating element is formed by laminating an ultraviolet curable rubber sheet on the front and back sides of this heating element, and then ultraviolet rays are irradiated onto the rubber sheet to harden the rubber sheet, resulting in a completely bonded molded product. The present invention relates to a method for manufacturing a sheet heating element, characterized in that the sheet heating element is manufactured.

In the method for producing a planar heating element of the present invention, when using a solution of rubber as a carrier for carbon black and graphite, after mixing the conductive materials of carbon black and graphite, they are mixed by gentle mechanical stirring. It can be impregnated and coated onto a base material such as woven fabric or glass cloth to form a sheet, and the heating elements are uniformly dispersed without being subjected to much mechanical strain, exhibiting desirable properties as a planar heating element.

As the base material, it is desirable to use glass cloth from the viewpoint of heat resistance and shape stability.

Insulator sheets include 5BR (styrene-butadiene rubber), NBR (acrylonitrile-butadiene rubber),
UV-curable rubber compositions of synthetic rubbers such as EPDM (pro-pyrene terpolymer in ethylene), OR (polychloroprene rubber), 03M (chlorosulfonated polyethylene) are used. OR with excellent heat resistance, weather resistance, and electrical insulation.

When 03M is used, a planar heating element with excellent durability and flexibility can be obtained. The ultraviolet curable rubber composition is obtained by adding to rubber a monofunctional or polyfunctional acrylic or methacrylic ester derived from acrylic or methacrylic acid and a photopolymerization initiator. Rubber, acrylic or methacrylic acid ester, and a photopolymerization initiator can be kneaded and rolled using ordinary rubber processing machinery to form a sheet, or acrylic or methacrylic acid can be prepared by dissolving the rubber in a solvent and making a rubber solution. An insulating layer sheet can also be obtained by dissolving and mixing an ester and a photopolymerization initiator, impregnating and coating a woven fabric or glass cloth as a base material, and drying. In this case as well, the base material is heat resistant,
When considering shape stability, it is desirable to use glass cloth.

The insulating layer sheet remains uncrosslinked unless exposed to ultraviolet rays. The electrodes are attached to the heating element layer sheet by laminating the front and back sides and irradiating it with ultraviolet rays, thereby cross-linking and curing the insulation layer sheet, and at the same time cross-linking and adhering the insulator sheet - heating element sheet - insulation sheet. Because they are integrated, it becomes a planar heating element that does not cause peeling between layers.

(Example) The present invention will be explained below using examples.

Example I 100 parts by weight of CMS, 5 parts by weight of magnesia oxide, and 8 parts by weight of dipentamethylenethiuram tetrasulfide were kneaded with a kneading roll, dissolved in 200 parts by weight of toluene to prepare a rubber solution, and graphite was added to this rubber solution. Thickness Q of the heating element layer rubber solution obtained by mixing and dispersing 50 parts,
A heating element layer sheet having a thickness of 0.2 layers was obtained by impregnating and coating a Q3++am glass cloth with the heating element layer rubber solution and drying it. The volume resistivity of this heating element layer sheet is 2.
I×10Ωcm.

100 parts by weight of 0M5, 15 parts by weight of trimethylolpropane trimethacrylate, 10 parts by weight of glycidyl methacrylate, and 5 parts by weight of benzyl dimethyl ketal were kneaded with a kneading roll in a state where ultraviolet rays were blocked, and rolled.
．． A sheet of IN was made and used as an ultraviolet curable insulator layer sheet. The volume resistivity of this insulator layer sheet is 8.3
X 1015 Ωcm. Electrodes were attached to the heating element layer sheet, the front and back sides were covered with the insulator layer sheet, and after being crimped with a press roll, the front and back sides were heated to 1200~
By irradiating the layer with /- ultraviolet rays, a planar heating element with no interlayer separation was obtained.

When a voltage of 100 V was applied to this planar heating element, the temperature rose to 70°C in 10 minutes and remained at this temperature thereafter.

Example 2 The heating element layer sheet used in Example 1 was used. Dissolve 100 parts by weight of 0R in 200 parts by weight of toluene while blocking ultraviolet rays, and add 1 part by weight of trimethylolpropane trimethacrylate.
5 parts by weight of ethylcarpitol acrylate, 10 parts by weight of glycidyl methacrylate, and 5 parts by weight of benzyl dimethyl ketal were added and mixed with stirring to prepare an ultraviolet curable rubber solution. This rubber solution was impregnated and coated on Q and Q3m glass cloth, and after drying, a 0.2811 ultraviolet curable insulating layer sheet was obtained. The volume resistivity of this insulating layer rubber sheet is 7. It was 1015Ω.

After attaching electrodes to the heating element layer sheet, covering the front and back sides with the insulating layer sheet, and press-bonding with a presser roll, a high-pressure mercury lamp is used to irradiate the front and back sides with ultraviolet rays of 1200 mg/c- to create a surface that does not peel between the layers. A heating element was obtained. When a voltage of 100V is applied to this sheet heating element, 7
The temperature rose to 0°C and was maintained at this temperature thereafter.

(Effects) As explained above, after laminating the heating element layer sheet of the present invention with an ultraviolet curable rubber sheet as an insulating layer on the front and back sides and press-bonding, the bonded surfaces are cross-linked and bonded by short-term irradiation with ultraviolet rays. It is possible to easily manufacture a heating element with a surface shape that does not peel off.

Procedural amendment l
.

February 18, 1986 Mr. Michibe Uga, Commissioner of the Patent Office
2.1. Indication of the case Patent Application No. 6547 of 1985 2. Name of the invention Method for manufacturing sheet heating elements 3. Person making the amendment Relationship to the case Patent applicant Hayakawa Rubber Co., Ltd. 4. Agent 5. Target of amendment: “1200 W9/ctx” in the 9th line of page 7 of the specification in the “Detailed Description of the Invention” section of the specification
Correct J to r l 200 mj/cm” J.

"l'-1200■/C-" on page 8, line 8, is 712
00 mj 7cm2 Corrected to J.

Claims (1)

[Claims] 1. A sheet-shaped heating element is formed by impregnating glass cloth with a rubber solution mixed with conductive carbon black or graphite, and laminating ultraviolet curable rubber sheets on the front and back sides of this heating element. A method for manufacturing a planar heating element, which comprises manufacturing the planar heating element as a completely bonded molded body by irradiating the rubber sheet with ultraviolet rays and curing the rubber sheet.