JPS603881A - Plastic molding heater having ptc property and method of producing same - 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 Field of Industrial Application This invention relates to a plastic molded heating element having PTC characteristics used for heat retention or heating using an element having a positive temperature coefficient (hereinafter referred to as PTC), and a method for manufacturing the same. It is related to.

Conventional configurations and their problems Conventional heating elements that utilize PTC characteristics include ceramic systems (for example, containing barium titanate as the main component) and plastic systems, but among them, molded plastic heating elements has been attracting attention in recent years because it has a high degree of freedom in shape and is still strong. However, in the case of plastic molded heating elements, the current method is to use conductor paste (mainly silver paste) as the collector electrode using methods such as screen printing; however, in this case, 1) the current capacity is small; It has drawbacks such as poor corrosion resistance, and difficulty in applying it to molded bodies with complex shapes.

Purpose of the Invention In view of the above-mentioned drawbacks, the present invention introduces a collector electrode construction method using metal plating, thereby creating a plastic molded collector electrode that can be applied to any complex shape, has a high current capacity, and has a highly reliable collector electrode. An object of the present invention is to provide a heating element and a method for manufacturing the same.

Structure of the Invention In order to achieve this object, the plastic molded heating element with PTC customization and the manufacturing method thereof of the present invention are subjected to surface enlarging treatment, and the surface is plated with metal to form a collector electrode. Since the collector electrode is made of metal, it has good conductivity and a high current capacity, and since it is a plating method, it is possible to construct the collector electrode in a molded body with a complex shape. Depending on the selection, it is possible to construct a collector electrode with excellent corrosion resistance.

DESCRIPTION OF THE EMBODIMENTS An embodiment of the present invention will be described below with reference to FIGS. 1 to 6.

FIG. 1 is an example of the manufacturing process of a collecting electrode configuration of a plastic molded heating element with a custom PTC. In FIG. 1, the surface of the molded body material (FIG. 2, FIG. 1) is subjected to surface enlarging treatment (preferably mechanical honing by sandblasting) (FIG. 3). Next, after degreasing and cleaning with an alkaline aqueous solution, pretreatment is performed using the catalytic accelerator method, and electroless plating with copper, nickel, etc. is applied. At this time, the thickness of the plating material is 0.2 to 0.5 μm, which is sufficient because the purpose is to provide an electrode for electrolytic plating in the next step. Then, in this state, annealing is performed in a wet state such as in boiling water. Furthermore, electrolytic plating is then performed using the electroless plating layer described above as a plating electrode (FIG. 4). As the material for this electrolytic plating, it is necessary to select a flexible material that can follow the coefficient of thermal expansion of the molded body material 1.
Furthermore, the thickness of the plating material must be determined in consideration of the current capacity required for the final heating element product.

Next, overplating is performed by selecting a material such as nickel, gold, or tin to provide corrosion resistance against salt water, oil, sulfide gas, etc. Finally, as shown in FIG. 5, the electrode plated portions are partially removed to form opposing collector electrodes 2a and 2b. Figures 2 to 5 are for flat plates with simple shapes, but as shown in Figure 6, cylinders or other complex shapes can be easily handled using the process shown in Figure 1 above. is possible.

The purpose of the above-mentioned surface enlarging treatment is to roughen the surface of the molded body material and improve the adhesive strength of the metal plating layer formed thereon by the anchoring effect of the metal plating layer. The degree of surface roughness is set to be 6 μm or more in terms of Ra. This is clear from the fact that the adhesive strength of the plated electrode shows a steady value at Ra of 6 μm or more, as shown in FIG. Note that the surface roughness of the material without surface enlarging treatment is approximately 0.4 μm in Ra, and when a collector electrode is formed on it, the adhesive strength is approximately 25 g/10
mm, which is extremely low.

Next, more specific embodiments of the present invention will be described.

The surface of a molded heating element element layer with a custom-made PTC made by heating and compression molding a mixture of powder obtained by pulverizing a mixture of polyvinylidene fluoride and carbon black and an epoxy resin, which is a thermosetting resin, to harden it. The surface was enlarged using a blasting material (for example, fused alumina particles No. 30).

Next, degrease with 10% sodium hydroxide aqueous solution at 70°C for 3 minutes, wash with water, pre-treat with catalyst accelerator method, and then apply electroless copper plating to approximately 0.3 to 0.5
μm was applied. Next, it was annealed in boiling water for about 10 minutes, then copper birophosphate plating was applied to a thickness of about 10 μm, and then electroless nickel plating was applied as Olver plating.

Finally, after aging (60 minutes at 150° C.), the plated portion was partially removed as shown in FIGS. 6 and 6 to obtain a product as an opposing collector electrode.

In the above manufacturing process, the surface roughness of the molded body material after the surface enlargement treatment is 6 to 7 μm in Ra, and the adhesive strength of the collector electrode of the final product is approximately 10 mm at the beading strength of 10 mm. 450g, and even when placed on the collector electrode of the heating element, the appearance has been maintained even in various reliability tests such as -30℃←→200℃ thermal shock test, intermittent current test in a bath at 80℃ and 95% relative humidity, etc. There were no problems with the construction or the electrical customization. In addition, when wet aging is applied in the above manufacturing process, the strength is increased by about 10% compared to the beer strength of about 400 g when not applied, so it can be said that this wet annealing is an effective process. Further, the reason why electroless plating was selected as the oval plating was to obtain an average plating layer from the viewpoint of corrosion resistance, and the thickness of the plating material was set to about 6 μm in order to reduce the occurrence of pinholes.

According to the plastic molded heating element with custom-made PTC and its manufacturing method of the present invention, which has more than the effects of the invention, metal plating is adopted as the collector electrode, so a high current capacity can be obtained, and the entire surface of the molded body material is It can be used even if the shape of the heating element is complex because it is plated and then a part is removed to make a collector electrode. Furthermore, a highly reliable heating element with excellent environmental properties such as melting resistance can be provided. Furthermore, since the surface is enlarged by sandblasting, the anchoring effect of the metal plating part creates a strong bond between the material and the plating material, and the roughened state of the heating element surface is maintained in the final product. As a result, in the case of heating a liquid, for example, there is an effect of increasing the heat generation efficiency because the contact area with the liquid is large.

[Brief explanation of the drawing]

Figure 1 is a process diagram showing the manufacturing process of a molded heating element in an embodiment of the present invention, Figures 2 to 6 are perspective views of the molded heating element in the same process, and Figure 6 is another embodiment of the invention. A perspective view of
FIG. 7 is a diagram showing the adhesive strength with respect to the surface roughness of the collector electrode of the shaped heating element of the present invention. 1... Molded body material, 2a, 2b... Opposing collector electrode. Name of agent: Patent attorney Toshio Nakao and 1 other person 1st
Figure 2 Figure 3 Figure 4

Claims (4)

[Claims] (1) A plastic molded heating element having PTC characteristics, characterized in that the collector electrode is formed by applying metal plating on the molded body. (2) A method for manufacturing a plastic molded heating element having PTC characteristics, comprising the steps of subjecting the surface of the molded body to an enlarging treatment and forming metal plating on the surface of the molded body. (3) Plastic molding heat generation with PTC customization according to claim 2, characterized in that the surface roughness of the molded product is 6 μm or more in center line average roughness (Ra) as measured by a Talysurf surface roughness meter. How the body is manufactured. (4) The step of applying metal plating to the surface of the molded body includes applying metal plating to the entire surface of the molded body, and then applying metal plating to the entire surface of the molded body, and then applying metal plating to the surface of the molded body.
3. A method for manufacturing a plastic molded heating element having PTCM properties as claimed in claim 2, characterized in that the step is to remove a portion of the heating element and configure it as a collector electrode.