JPS6279270A - Resin heating thermogenic material - Google Patents

Abstract

PURPOSE:A resin thermogenic material, obtained by surrounding the periphery of a resin thermogenic material consisting of a molded electrically conductive resin article of an optional shape with an insulating resin, particularly a thermosetting resin and having improved safety, uniform thermogenic property, heat releasing property, air permeability, water permeability, heat insulating property, etc. CONSTITUTION:A resin thermogenic material, constituted of a molded article 1 consisting of an electrically conductive resin (containing an electrically conductive material in a thermoplastic or thermosetting resin) of an optional shape and a layer 2, surrounding the above-mentioned molded article 1 and consisting of an insulating resin, preferably a thermosetting resin, e.g. epoxy resin, and obtained by forming an insulating protective film 3 on the surface of the molded article 1 of the electrically conductive resin for improving the safety, filling a filler having good thermal conductivity in at least one surface of the insulating resin 2 to give heat release property and incorporating or placing a filler having good heat insulating effect on the surface 5 of a part in which the molded article 1 of electrically conductive resin 2, e.g. hollow pipe, to afford heat insulating property.

Description

Detailed Description of the Invention (Field of Industrial Application) The present invention relates to a resin heating element, and more specifically, to safety,
Uniform heat generation, heat dissipation, breathability, and water permeability.

The present invention relates to a resin heating element having a novel structure that has excellent performance as a resin heating element such as heat insulation properties.

(Prior Art) Conventionally, resin heating elements made by kneading conductive agents such as conductive carbon or metal powder into various thermoplastic resins and molding them into desired shapes have been known, and are used in floor heating, foot warmers, and heat insulation. It is widely used as a heating member for various heating tools such as panels.

(Problem to be solved by the invention) The resin heating element as described above is made by kneading a conductive agent such as conductive carbon black at a high concentration into a thermoplastic resin and molding it, and generates heat by passing an electric current through the resistance. Therefore, the conductive agents mixed in must be in contact with each other and uniformly dispersed. However, it is extremely difficult to uniformly disperse a large amount of conductive agent in a thermoplastic resin, and as a result, the physical strength of the molded product is significantly reduced, and during use, the temperature rises due to local heat generation or heat generation failure. In the case of a panel-shaped resin heating element having a large area, uneven heating may occur, and local overheating may occur due to localized heat dissipation defects, which poses a serious problem in terms of safety.

Also, during use, the temperature is always higher than the ambient temperature, so
The resin heating element itself is subject to severe thermal deterioration and oxidative deterioration, especially on the surface, and the above-mentioned problems become more and more serious after long-term use.

Regarding the problem of decrease in physical strength, it is considered that reinforcing materials such as glass fiber are mixed in at the same time, but these methods make manufacturing more difficult and quality control becomes more stringent. , the above problems remain largely unsolved.

As a result of intensive research in order to solve the problems of the conventional technology as described above, the inventor of the present invention has developed an insulating resin around the conventional resin heating element.
In particular, the present invention was completed based on the finding that the above-mentioned problems of the prior art can be sufficiently solved by surrounding it with a thermosetting resin.

(Means for Solving the Problems) That is, the present invention is a resin heating element characterized by comprising a conductive resin molded body having an arbitrary shape and an insulating resin surrounding the molded body.

The invention will now be described in more detail with reference to the accompanying drawings, which illustrate preferred embodiments of the invention.

Fig. 1 shows a sectional view of one example of the resin heating element of the present invention, Fig. 2 shows a sectional view of another example during manufacture, and Fig. 3 shows a sectional view of another example. It shows.

First, referring to FIG. 1, the resin heating element itself of the present invention is as follows:
Basically, it is composed of a conductive resin molded body 1 of any shape and an insulating resin layer 2 surrounding the molded body 1.

The conductive resin molded body 1 itself may be of a conventionally known type,
For example, polyethylene, polypropylene, polysulfone,
It is molded by kneading a conductive agent, such as conductive carbon black or metal powder, into a thermoplastic resin such as polyester, polycarbonate, or fluororesin at a high concentration, and its shape can be linear, rod-like, or columnar. Any of these conductive resin molded bodies 1, which may have any shape and size such as a flat plate shape, can be easily manufactured by conventionally known techniques.

The insulating resin layer 2 surrounding the conductive resin molded body 1 may be made of any resin as long as it is electrically insulating, but particularly preferred is one made of thermosetting resin such as epoxy resin. It is.

In such a resin heating element 10 of the present invention, safety can be further enhanced by forming an insulating protective coating 3 on the surface of the conductive resin molded body 1. In addition, the surface of the insulating resin 2 surrounding the molded body 1, which will become the heat dissipation surface 4, is filled with a filler having good thermal conductivity (for example, an inorganic filler or metal powder) to improve its heat dissipation. It is preferable to mix or arrange a filler with a good heat insulating effect (for example, a white glass balloon, a hollow pipe, etc.) in the portion that is to become the strong heat insulating surface 5.

Next, referring to FIG. 2, FIG. 2 also shows a method for manufacturing the resin heating element itself of the present invention, and 6 in the figure is a mold for molding, and preferably The method of the present invention is achieved by arranging a plurality of conductive resin molded bodies 1, injecting a thermosetting resin such as a thermosetting epoxy resin into the gap between the mold 6 and the molded bodies 1, and solidifying this. A resin heating element n is obtained. In such a method, the insulating resin 2 formed may be a uniform layer as a whole, but depending on the use of the resin heating element obtained, at least one surface 5 is made heat insulating and the other surface 4 is made heat radiating. In order to make one side heat-insulating, it is preferable to make one side heat-insulating, for example, by first injecting a thermosetting resin containing a heat-insulating filler into the formwork. A method in which a heat insulating layer 5 is formed using a heat insulating layer 5, and then a thermosetting resin mixed with a filler having good thermal conductivity is injected to form a heat dissipating surface 4, as shown in FIG. Any method such as burying etc. may be used.

In addition, when obtaining a flat resin heating element as shown in FIG. 2, holes 8 are provided in the portion of the flat plate where the resin heating element does not exist, so that the resin heating element is shaped to have air permeability, water permeability, etc. It can also be set to body-10.

(Operations/Effects) According to the present invention as described above, a conventional conductive resin is formed into a molded body of an arbitrary shape, and the molded body is embedded in a thermosetting resin and solidified to form a desired shape. This solves various problems in the prior art, such as insufficient strength and thermal deterioration of the molded body. In addition, by making the conductive resin molded body into a large number of linear or rod-shaped bodies, it is possible to freely control the heat generation temperature and solve various problems such as abnormal heat generation, heat generation failure, and uneven heat radiation. . Further, since any surface of the obtained resin heating element can be used as a heat insulating surface or a heat radiating surface, a trowel suitable for various uses can be obtained.

Further, since arbitrary safe ventilation holes and water passage holes can be provided in the resulting resin heating element, the uses of the resin heating element can be significantly expanded.

Therefore, the resin heating element of the present invention can be used as a dew condensation preventer.

Futon dryers, floor heating, foot warmers, chair heating, desk heating, neuralgia rheumatism treatment, car battery insulation, seedling insulation, artificial incubators, livestock insulation, snow melting panels, bath floors, thermal panels, bath tank insulation, concrete curing It is useful for heat insulation, freezer door freezing prevention, water water freezing prevention, copier preheating, railway point rail insulation, tropical fish pickling insulation, water bed insulation, heat exhaust duct convection discharge device, washstand, hot water equipment, etc.

(Example) Conductive carbon was kneaded into a thermoplastic resin at a ratio of 39 phr and molded into a rod shape with a diameter of 4.5 mm. The molded body was cut into a length of 8001 mm, and power supply connection terminals were attached to both ends thereof. As a formwork for molding, depth 20 layers set length 90
A flat plate-shaped mold with a width of 90 cm and a width of 90 cm was prepared, and synthetic resin pipes with an outer diameter of 5 cm and an inner diameter of 4 cm were arranged at intervals of 20 cm on the bottom. Ten of the molded bodies described above were fixed at 40 mm intervals in a direction perpendicular to the lined synthetic resin pipes, and a thermosetting epoxy resin containing an inorganic filler at a rate of 30 phr was injected into the voids in the mold. The molded body was buried.

Next, the entire mold was heated to approximately 40 to 60° C. for 2 to 3 hours to cure the entire mold, thereby obtaining a resin heating element of the present invention.

A 100V power source was connected to the power source connection portion provided at the end of this molded body. The elapsed time, current consumption, and temperature of heat generation were measured at a room temperature of 16° C. and a humidity of 60%, and the following results were obtained.

Kusara j turtle 1! Ej hit flA shinsan ■ uni 0:
00 1300 --1 : 00
1350 302:00 950
623:00 s'oo
764:00 790 825
: 00 770 876:00
740 91 In addition, when the voltage applied to the resin heating element of the present invention was varied and the temperature at 10 points of the resin heating element after a certain period of time was measured, as shown below, a certain level of heat generation was observed, indicating an abnormality. No fever was observed.

1234567811110 (Measurement point) Comparative example Using the same conductive resin as used in the example, a heating panel with the same dimensions as the heating element of the example was made from this conductive resin, and connected at both ends in the same manner as in the example. By providing a terminal and changing the applied voltage, the lO of the resin heating element after a certain period of time has elapsed.
When we measured the temperature at several points, as shown below, significant temperature differences occurred in each part of the heating element at around 70°C, and in extreme cases, temperature differences of as much as 50°C were observed.

(Left below) No Turtle 1 ,, =20
℃123458781110 (measurement point)

[Brief explanation of drawings]

1 to 3 are diagrams schematically showing cross sections of the resin heating element of the present invention. l; Conductive resin molded body 2; Insulating resin 3; Protective coating 4; Heat dissipation surface 5: 11#1 surface et al.: Formwork 7; Hollow pipe 8: Vent hole and; Resin heating element Patent applicant Kyowa Shokai Co., Ltd. (1 other person) Figure 1

Claims (7)

[Claims] (1) A resin heating element comprising a conductive resin molded body of any shape and an insulating resin surrounding the molded body. (2) The conductive resin is a thermoplastic resin or a thermosetting resin containing a conductive agent.
) The resin heating element described in item 2. (3) The resin heating element according to claim (1), wherein the insulating resin is made of a thermosetting resin. (4) The resin heating element according to claim (1), wherein the insulating resin is made of a thermosetting epoxy resin. (5) The resin heating element according to claim (1), wherein at least one surface of the insulating resin is heat dissipating. (6) The resin heating element according to claim (1), wherein a plurality of conductive resin molded bodies are arranged in an insulating resin. (7) The resin heating element according to claim (8), wherein holes are provided in the portion where the conductive resin molded body is not arranged.