JPS62125602A - Ptc device - 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] The present invention relates to an electric element, and more particularly to the property that the resistivity of the element rapidly increases in a relatively narrow temperature range as the temperature increases. C characteristic (Positive temperature)
It relates to an electric element, that is, a PTC, which has a certain characteristic (coeHcient).

[Prior art and its problems]

Substances with PTC characteristics are used in heaters that stop generating heat after reaching a certain temperature of 1 J, and positive characteristic thermistors (PTCth
It can be used as a protective element that opens a circuit when a short circuit occurs in a heat-sensitive sensor, a dry cell battery, etc., and closes the circuit when the short circuit is removed. Therefore, the development of substances with PCT properties has been progressing for a long time, such as those in which monovalent or trivalent metal oxides are added to regular B a T i O3, and carbon black particles in polymers such as crystalline polyethylene. Some have conductive substances dispersed in them.

Conventionally, an electric element having PTC characteristics (hereinafter abbreviated as PTC element, for example, as shown in FIG. 2, consists of a molded body 1 having PTC characteristics and electrode plates 2a and 2b sandwiching it, The two electrode plates 2a and 2b are electrically connected by S-conductor adhesive or thermocompression bonding.

However, the end face of this element has not been subjected to any processing, and as a result, the electrode plate may peel off from the end face of the element, or the element may be damaged in some way, resulting in a short circuit between the electrodes. There were problems with reliability and safety.

(Means for solving the problem) The flaws on the element that impair the reliability and safety of the conventional PTC resistor are completely covered by the end face of the PTC element, that is, the electrode C. This occurs on and near the surface of the molded product. As a result of conducting various trial production studies, the present inventors have found that coating the end faces of the water droplet with an insulating resin film is effective in achieving the object of the present invention, and has completed the invention.

The PTC element of the present invention is a PTC element consisting of a molded body having PTC characteristics and a plurality of electrodes provided on the surface of the molded body, in which the surface of the molded body that is not covered with the electrodes is covered with an insulating resin film between the electrodes. It is characterized by being coated with.

This invention will be explained in more detail below.

I would like to introduce PTC special bamboo that can be used in this invention.
Examples of such materials include mixtures of polymers and conductive particles. Examples of this polymer include polyethylene, polyethylene oxide, t-4-polybutadiene, polyethylene acrylate, ethylene-]-]delacrylate 1 to
Copolymer ethylene-acrylic acid copolymer, polyester, polyamide, polyester, polycaprolactam, fluorinated ethylene-propylene copolymer, chlorinated polyethylene, chlorosulfonated polyethylene, ethylene-vinyl acetate copolymer, polypropylene , polystyrene, styrene-acryloni-1-lyl copolymer, polyvinyl chloride, polyvinylidene chloride, polyvinyl acetate, polycarbonate-1-
, polyacetals, polyalkylene oxides, polyphenylene oxides, polysulfones, fluororesins, and blend polymers thereof, etc., can be used to prepare materials with PTC properties. The type of polymer, composition ratio, etc. can be changed as appropriate depending on desired performance, use, etc.

In addition, examples of conductive particles dispersed in the polymer include graphite,
Particles of conductive materials such as tin, silver, gold, copper, etc. can also be used.

1st C characteristic]'? In preparing the material, various additives may be mixed as necessary in addition to the above-mentioned polymers and conductive particles. Examples of substances that can be added include flame retardants such as andimone compounds, phosphorus compounds, chlorine compounds, and bromine compounds, and antioxidants.

In the present invention, the substance having PTC characteristics is prepared by mixing its raw materials, such as polymers, conductive particles, and other additives L'j, in a predetermined ratio. Prepared PTC
Materials with properties are molded into certain shapes and dimensions.

This molding method is carried out by a conventional method as long as it does not impair the P-C properties. For example, humidity between 100℃ and 200℃,
The mixture is shaped by means of a roller or press at a pressure of 20 tons/(600×500 mm plate).

A plurality of electrodes are provided on the surface of a molded body having PTC characteristics by a conventional method. The arrangement of electrodes is not limited in this invention. It is desirable to change the shape, dimensions, properties, plating, and other treatments of the electrodes depending on the intended use, performance, etc. of the device of the present invention.

In this invention, the surface of the molded body that is not covered with electrodes is covered with an insulating resin film C between the electrodes. The type of resin that can be used in this invention is not limited as long as it does not contradict the purpose of this invention. Examples of the resin include polyethylene, polypyrene, polyvinyl chloride, polyvinyl acetate, polyvinyl alcohol, acrylic resin, fluororesin, polyamide resin,
Polycarbonate 1 - resin, polyacecool resin, polyalkylene oxide, saturated polyester resin, polyphenylene oxide, polysulfone, polyp-xylylene, polyimide, polyamideimide, polynisdelimide, polybenzimidazole, polyfur-nylene sulfide,
Silicone resin, phenolic resin, urea resin, melamine resin, furan resin, alkyd resin, unsaturated polyester resin, diallylphtathy resin, T-poxy resin, polyurethane resin, blend polymers thereof, reaction with chemical reagents, radiation bridge There are modified resins such as polymers and copolymers. Particularly preferred among these are eboxy resin d3 and f-nor resin.

These resins contain various additives such as plasticizers, lubricants, crosslinking agents, jXI sulfur agents, curing agents, antioxidants, ultraviolet absorbers, fillers, reinforcing agents, reinforcing agents, modifiers, Antistatic agents, flame retardants, colorants, heat stabilizers, softeners, tackifiers, binders, anti-stick agents, surface treatment agents, (=j fragrances, fungicides, termite control agents, rat repellents) Agents etc. may be added.

The resin that can be used in this invention has at least an insulating property, and is preferably used on the electrode surface,
It has adhesion to the surface of the molded product.

The method of coating the resin film is not particularly limited in this invention,
For example, spraying, smearing, immersion in resin liquid, etc.

The resin IIQ is coated at least on the surface of the molded body not covered with the electrodes, and also between the electrodes. However, the surface of the element other than (a) may be coated.

Curing of the resin after application can be carried out by a conventional method depending on the resin, such as chemical treatment, heating, or radiation irradiation. The thickness of the resin film depends on the type of resin, the purpose of the device, and
It can be changed as appropriate according to the 4 methods.

After other processing and connection of lead plates, the iq PTC element is used for a predetermined purpose.

An example of the element of the present invention and a partially cut away perspective view of FIG. 1 will be used to explain. This element consists of a molded body 1 having PTC characteristics and two electrode plates 2a and 2b that sandwich it.
The device is composed of lead plates 3a and 3b connected to electrode plates, and the end surfaces of the device are covered with an insulating resin film 4.

(Effect of the invention) Since the end face of the PTC element is coated with an insulating resin, the electrode plate may peel off due to external force, etc.
Short circuits between electrodes due to damage to the C element can be prevented, and a PTC resistor with superior reliability and safety can be provided.

〔Example〕

This invention will be explained more specifically by way of examples.

Example 1 7 kg/
Compression molding was performed using a press at crA pressure to form a molded product with a predetermined shape and dimensions.

Weight% Polymer High Density Polyethylene 59 Conductive Particles: Carbon Black 40 Additives: Phenolic Antioxidant 11! A nickel electrode plate was directly stacked on the molded body, and epoxy resin (Evoream, manufactured by Mitsubishi Kasei) was applied. The resin film is 150
C. for 20 minutes (heat treatment) to cure, forming a resin film with a thickness of about 50 μm. PTC coated with this cured resin film
I got the element. This device was highly reliable and safe, with no peeling of the electrode plate or short circuit.

Example 2 A material having the composition F and having P T'C properties was formed into a molded article in the same manner as in Example 1.

Weight % Polymer bilinear low density polyethylene 5 Conductive particles: Carbon black 40 Additives: Phenolic antioxidant 1 A nickel electrode plate was directly layered on the obtained molded body, and epoxy resin (Scotch Cast, manufactured by 3M) was used. was applied. The resin film was heated to 150℃.
It was cured by heat treatment for 20 minutes to form a resin film with a thickness of about 50 μm.

[Brief explanation of drawings]

FIG. 1 is a partially cutaway perspective view showing an example of a PTC element according to the present invention, and FIG. 2 is a perspective view not showing an example of a conventional PTC element. 1... Molded body, 2a, 2'o-... Electrode plate, 3a, 3
b... Lead plate, 4... Insulating resin film. Applicant's agent Sato - Yu 1 Figure 3 1 - Itoshi Kidney;
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391 fH2 Name of invention p T-C search r 3 Supplementary W to 16 things ('1 which relationship Q2 + machine'1 out ■ (person Japanese me/)
1-Ron Co., Ltd.? 1 4 Deputy Director 6-Supplementary QF-13 Yoichisu-□゛'-;-Lee F Ming-
-'1- 8 Contents of Supplement 1-1- (1) "Open the circuit" on page 2, line 43 of the specification is changed to "
As the ηi current increases, it self-heats with Joule heat, thereby increasing the resistance and limiting the rl current to below a predetermined value [
1. Revised I to 1F. (2) "Close" in the 4th line of page 2 of the specification is revised to 1, which returns. 3) “PcTJ to rPTC” on page 2, line 5 of the specification
” Revised IF.

Claims (1)

[Claims] A PTC element consisting of a molded body having PTC characteristics and a plurality of electrodes provided on the surface thereof, characterized in that the surface of the molded body that is not covered with electrodes is covered with an insulating resin film between the electrodes. PTC element.