JPS5857285A - Method of producing sectional different shape heater - 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 manufacturing a planar heating element with an irregular cross section.

A flat planar heating element is made by impregnating a thermosetting resin composition in which conductive fibers are dispersed between the insulating edges #JkMll.
M is obtained, and a thermosetting resin is hot-press-molded on both sides of this conductive layer using a mold. However, when manufacturing a planar heating element with an irregular cross section using this method, the more complex the shape, the more complicated the flow of resin within the mold becomes. ni+
JP conductive fibers will also result in non-uniform flow. As a result, the orientation of the conductive fibers in the conductive layer &: and the contact state between the fibers are disturbed, the conductive layer becomes uneven and discontinuous, and the conductive layer no longer has a uniform heat generation distribution.

The present invention was made in view of the first century, and an object of the present invention is to provide a method for manufacturing a WLR-oriented irregular-shaped planar heating element having a uniform heat distribution.

The method for producing a planar heating element with an irregular cross section according to the present invention involves impregnating a thermosetting resin composition in which conductive fibers are dispersed between two insulating fiber layers to obtain a conductive layer. layers &
After holding the required irregular cross-section and heating and curing it so that no flow occurs, 4% of this irregular cross-section! It is characterized in that a thermosetting resin is hot-press-molded on both sides of the L layer.

The conductive fiber used in the present invention has an electrical resistance of 10""
It is preferable that n −c+a or less, and for example, steel fibers, stainless steel fibers, carbon fibers, etc. are used, and carbon fibers are preferably used. The longer the carbon fibers are, the more easily they come into contact with each other, which reduces the electrical resistance of the conductive layer.Also, when the insulating fiber layer is impregnated with a resin composition, it tends to remain on the surface of the fiber layer. If the length is too long, the fibers will become entangled with each other when dispersed in a thermosetting resin, resulting in uneven dispersion. Therefore, it is usually 0.3 to 25M, preferably 3 to 10M. Also,
The thinner the conductive fiber is, the more preferable it is, and the conductive fiber is V# thread and 50μ or less.

The thermosetting resin for dispersing the conductive fibers is not particularly limited, but unsaturated polyester resins, epoxy resins, etc. are usually used, and the resin composition may contain catalysts, curing agents, fillers, etc. as necessary. , a thickener, etc. are added. The resin composition usually contains 0.4 to 3 conductive fibers per 100 parts by weight of resin.
0 parts by weight, 50 to 100 parts by weight of fillers, including calcium carbonate, alumina, clay, talc,
A material having better thermal conductivity than resin such as mica is preferably used.

Guide! ! The shoe is obtained by impregnating two insulating fiber layers with a thermosetting resin composition containing conductive fibers as shown in L. As shown in FIG. Press with an impregnating roll 5 of 1 roll, etc., and roll 1 horizontally.
1if (1) The composition is impregnated into the curve of two insulating fiber layers, and the lead tllrj6 is wound up.

During impregnation with the resin composition (as shown in Figure 2),
It is desirable to select the viscosity IIJ' of the resin composition, the speed of coating, the N attachment, the thickness, etc. of the insulating fiber layer so that the resin composition 2 does not penetrate to the surfaces of the insulating fiber layers 1 and 4. In other words, it is desirable that the insulating fibers 1- are not impregnated with resin on the surface of the 4-strand 6 and are exposed. i44 like this
By exposing a fiber layer with no pro-eutectic precipitation and poor impregnability on the layer surface, when forming an insulating layer by hot-pressing a thermosetting resin as described later, the conductive layer and the insulating layer can be easily separated. Strong (
This is because they are all in close contact with each other.

The edge-supplying fibers are preferably thermosetting resins with excellent N-containing properties, such as polypropylene, polyvinyl alcohol, polyester, polyamide, wool, cotton, fabric,
Woven fabrics, non-woven fabrics, etc. made of glass fiber etc. are used, but
Chopped strand mats, continuous strand mats, glass cloth, etc. made of glass fibers are preferably used because of their affinity with thermosetting resins.

In the present invention, the conductive seven layers obtained in this way are held in a required irregular cross section so that only resin flows, and are heated and cured without substantially applying pressure. The temperature of this preheating depends on the thermosetting resin used, but in the case of unsaturated polyester resin, it is about 130 to 160°C, and the heating time is about 1 to 10 minutes. It should be noted that during preheating, there is no problem in applying a small surface pressure to the conductive layer in order to maintain the conductive layer in the required irregular cross-section, but if the surface pressure increases, the resin will flow during heating and this will cause the resin to flow. This not only disturbs the orientation and contact state of the conductive fibers, but also causes the resin to penetrate into the surface of the insulating fiber layer, which is undesirable because the exposed fibers on the surface of the conductive layer are buried in the resin.

Next, as shown in FIG. 3, M layers of a thermosetting resin composition 7 are applied on both sides of the conductive layer 6 having an irregular cross section obtained in this way, and a mold is formed by hot pressing using a mold. For example, an atypical cross-section of hemorrhagic fever may be obtained. The thermosetting resin composition is prepared by blending unsaturated polyester resin, epoxy resin, etc. with catalysts, curing agents, fillers, thickeners, etc. as necessary in the same manner as described above, and glass fiber etc. as reinforcing agents. It may contain insulating fibers as described above. Therefore, 8MO of crow braid can be used as a preferred laminating material.

The heating temperature and pressure in hot pressure molding depend on the heat-curing resin used, but in the case of unsaturated polyester resin,
The temperature is about 130-160″C, and the pressure is 5-80 Kf.
/C- level.

As described above, the present invention impregnates a thermosetting 1rM resin in which conductive fibers are dispersed between two insulating fiber layers to create #W,
III, hold this conductive layer in the required cross section,
Since heat curing is performed without applying substantial pressure, resin flow does not occur, and therefore the orientation and contact state of the conductive &1 fibers are maintained. Thermosetting resins are then laminated and hot pressed to form an insulating layer, making it possible to obtain a planar heating element with a complex irregular cross section while maintaining the uniform heat generation distribution of the conductive layer.

Furthermore, by exposing the insulating fiber layer on the surface of the conductive layer when manufacturing the conductive layer, the conductive layer and the insulating layer are firmly bonded, so R peeling does not occur even when the conductive layer is energized or heated. Moreover, since the insulating layer is hot-pressed,
The surface of the obtained sheet heating element is smooth and beautiful, and there are no surface defects such as pinholes, so it has excellent durability such as water resistance.

Examples are given below. In addition, the part means the heavy general part.

Example 100 parts of unsaturated polyester resin, 1 part of catalyst, 0.03 parts of polymerization inhibitor, 0.5 parts of thickener and 4.0 parts of internal mold release agent were mixed and stirred, then 1301s of calcium carbonate was added.
After stirring, carbon fiber 1 with a diameter of 12.5 μm and a length of 6 μm
1 part and stirred to prepare a thermosetting resin composition.

Using the apparatus shown in Figure IN1, the above-mentioned wood-stripping composition 2 is applied to a thickness of about 0.0 mm on a glass nonwoven fabric running at a speed of 1 m for 7 minutes.
After coating 7M, a glass fiber chopped strand mat 4 with a weight of 600 f/ln' was laminated, and the resin composition was impregnated so as not to penetrate into the surface of the glass mat.
Wound into a roll. This was cured at 40''C for one week to thicken it to obtain a conductive layer.

This conductive layer was folded into an irregular cross section at 140'C.
It was heated for a minute to harden to obtain a barrel* layer with an irregular cross section. As shown in Figure 3, this conductive layer is made up of two sheets of similar shape +7) 8
MC! G: Sandwich, mold center te 150”C130Kl//
Hot pressure molding was carried out for 5 minutes under the conditions of Cd to obtain a planar heating element with an irregular cross section according to the present invention.

Comparative Example 1 Using kraft release paper instead of glass non-woven cloth, a carbon fiber-containing mallet Hit composition was applied to a thickness of i and osa, and then a glass fiber chopped strand mat with a basis weight of 1130011/- was laminated. Other than that, a conductive layer was obtained in the same manner as in Example 1, and the cross-section was made into an irregular shape in the same manner as in Example, and after preheating,
The insulating layer was hot pressed.

Comparative Example 2 The conductive layer obtained in Comparative Example 1 was bent into an irregular cross section, 8MO was layered on both sides without preheating, and hot-press molded under the same conditions as in the example.

The tooth strength, heat generation temperature distribution, and insulation test results of each planar heating element obtained as described above are shown in the table.

In addition, each test was conducted as follows.

(! fT impact strength...1 ~ An eggplant-shaped heavy hammer was dropped from a predetermined height onto the center of the curved heating element, and the surface condition was observed.

Heat generation temperature distribution: Apply AC voltage between electrodes,
When the maximum temperature reached 90°C, the electricity was turned off and the temperature on the surface of the heating element was measured.

Insulation test... Connect the green liquid W electric wire to the electrode, seal the connection point, and submerge it in water for 60 minutes.
Insulation resistance was measured using a KV mega tester.

[Brief explanation of drawings]

FIG. 1 shows an example of iron making for manufacturing 1J4vL mausoleum in the method of the present invention, and FIG. 2 is a cross-sectional view of the guiding layer;
FIG. 3 is a sectional view showing an example of a cut W1-shaped blood cane mature body obtained by the method of the present invention. ] - Insulating edge fiber layer, 2... thermosetting resin composite, 4
・End ++ Edge loose chest, 7... Thermosetting resin. 81 patentees Mototoshi Numa, Representative of Sekisui Chemical Co., Ltd.

Claims (1)

[Claims] (1) A conductive layer is obtained by impregnating a thermosetting resin composition in which conductive fibers are dispersed between two insulating fiber layers, and the conductive layer is heated as required to prevent resin flow. 1. A method for manufacturing a planar heating element with an irregular cross section, which comprises holding the conductive layer in an irregular cross section and curing it by heating, and then hot-pressing a thermosetting resin on both sides of the conductive layer of the irregular cross section.