JPS63211701A - 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 specifically, the present invention relates to an electric element, and more particularly, to a property that electrical resistance rapidly increases in a relatively narrow temperature range as the temperature rises [
PTC characteristics (Posltivc tca+perat-
The present invention relates to an electric element, a PTC element, and a PTC element.

[Conventional technology]

Substances with PTC characteristics (PTC compositions) are designed to reduce overcurrent to a predetermined current value when a short circuit occurs in a circuit that includes heaters, positive characteristic thermistors (PTCTIIERMISTER), thermal sensors, batteries, etc., which stop generating heat when the temperature rises to a certain level. On the other hand, it can be used as a circuit protection element that restores the circuit when the short circuit is removed. PTC
Currently, various substances have been developed as substances with properties, and conventionally, for example, monovalent or trivalent substances are added to B a T L Oa.
valent metal oxides, polyethylene,
There are polymers such as ethylene-acrylic acid copolymers in which conductive particles such as carbon black are uniformly dispersed.

The method for producing materials with this PTC property generally consists of adding and kneading the required amount of carbon black to one or more resins used as polymers. Furthermore, a conventional PTC element that utilizes a substance having PTC characteristics, for example, in which this substance is sandwiched between metal electrode plates, has a fifth
As shown in Figures (a) and (b), a substance 2 mainly having PTC characteristics and electrode plates 3a and 3b sandwiching it
and leads 4a and 4 connected to each of the electrode plates.
This substance having PTC characteristics is a composition comprising conductive particles dispersed in a polymer. That P.T.
In the method for manufacturing a C element, at least one polymer and conductive particles are kneaded at a temperature equal to or higher than the melting point of the polymer.
A material having TC properties is prepared, and this material having PTC properties is formed into a film. The material having PTC characteristics and the electrode plate are bonded to each other by thermocompression bonding the material having PTC characteristics to the electrode metal at a temperature near its melting point. The laminated body obtained by bonding is cut into a predetermined size, and leads are electrically connected to the electrode surface of this laminated body by soldering, spot welding, etc. to manufacture a PTC element.

[Problem that the invention seeks to solve]

However, in the structure of a conventional PTC element, a lead plate or a lead wire is electrically and mechanically joined to an electrode plate by welding or the like, and the lead terminal protrudes from the PTC element main body. Therefore, even if an attempt is made to increase the thickness of the PTC element, the thickness is limited only to the protruding parts of the leads.
Furthermore, it is difficult to mount a PTC element together with a semiconductor chip or the like on a circuit board in an automated line.

This invention was made based on the above background,
Its purpose is to limit (
To provide a PTC element in which the size of the PTC element can be changed and the PTC element can be mounted on a circuit board together with a chip such as a semiconductor on an automated line.

[Means for solving problems]

According to the present invention, this problem is solved by providing at least two electrodes and a PTC disposed between the electrodes and electrically connected to the electrodes.
A PTC element consisting of a substance having characteristics, said P
The TC element as a whole is substantially plate-shaped, each of the electrodes forms part or all of the end of the plate-shaped PTC element, and the distance between the positive and negative electrodes exhibits PTC characteristics. This is achieved by a PTC element that is longer than the thickness of the plate-shaped molded body made of the substance.

In a preferred embodiment of the present invention, each of the electrodes can form part or all of the side end surface of the plate-like PTC element.

As another preferred embodiment of the present invention, each of the electrodes can form part or all of the end portion of the same surface of the plate-like PTC element, and in this embodiment, the electrodes are further provided with the electrodes. A conductive layer can be formed on the surface opposite to the plate-like PTC element surface.

In another preferred embodiment of the invention, the substance having PTC properties comprises at least one polymer, electrically conductive particles dispersed in the polymer, and a thermally conductive filler dispersed in the polymer. and may include.

This invention will be explained in more detail below.

Material Having PTC Characteristics The PTC element of the present invention includes at least two electrodes and a material having PTC characteristics electrically connected to the electrodes. Materials with PTC characteristics include, for example, BaTiO3 to which monovalent or trivalent metal oxides are added, and polymers to which conductive particles and, if necessary, thermally conductive fillers are added. There is.

The polymers used in this invention include polyethylene,
Polyethylene oxide, t-4-polybutadiene, polyethylene acrylate, ethylene-ethyl acrylate copolymer, ethylene-acrylic acid copolymer, polyester, polyamide, polyether, polycaprolactam,
Fluorinated ethylene-propylene copolymer, chlorinated polyethylene, chlorosulfonated ethylene, ethylene-vinyl acetate copolymer, polypropylene, polystyrene, styrene-acrylonitrile copolymer, polyvinyl chloride, polycarbonate, polyacetal, polyalkylene oxide, polyphenylene Examples include oxides, polysulfones, fluororesins, and blend polymers of at least two selected from these. In this invention, the type of polymer, composition ratio, etc. can be appropriately selected depending on desired performance, use, etc.

The conductive particles dispersed in the polymer are made of electrically conductive substances, such as carbon black,
Particles of conductive substances such as silver powder, gold powder, carbon powder, graphite, copper powder, carbon fiber, nickel powder, and silver-plated fine particles can be used. The particle size of this conductive particle,
It is desirable that various specific surface areas and the like be appropriately selected depending on the use of the substance having PTC characteristics and desired characteristics.

In a preferred embodiment of the invention, the thermally conductive particles that can be dispersed in the polymer consist of thermally conductive inorganic or organic substances, such as, for example:
Examples include at least one substance selected from silicon, silicon nitride, silicon carbide, Bed, and alumina, and mixtures thereof. The particle size, specific surface area, etc. of this thermally conductive particle are
Various materials can be selected as appropriate depending on the use of the substance having PTC characteristics and desired characteristics.

In preparing the PTC composition, in addition to the above-mentioned polymer, conductive particles, and thermally conductive particles, various additives can be mixed as necessary. Examples of such additives include flame retardants, antioxidants, stabilizers, etc., such as antimony compounds, phosphorus compounds, chlorinated compounds, and brominated compounds.

In the present invention, the PTC composition is prepared by blending and kneading raw materials, polymers, conductive particles, thermally conductive particles, and other additives in predetermined proportions. In the present invention, the polymer may be prepared by blending and kneading conductive particles and then thermally conductive particles, or thermally conductive particles and then conductive particles, or both at the same time. Furthermore, when using two or more types of polymers, the polymer and the conductive particles and the thermally conductive particles are kneaded, and the polymer is pre-kneaded with the conductive particles and the thermally conductive particles for each polymer. Then, each pre-kneaded product may be main-kneaded at a predetermined ratio. This kneading is performed by kneading the polymer, electrically conductive particles, and thermally conductive particles. The blending ratio of the polymer and particles can be appropriately selected depending on the particle content of the target composition, the type of polymer, the mixer, the type of Ni-Goo, etc. In this invention,
Pretreatment such as crushing, heating, and mixing may be performed before kneading.

The temperature during kneading is in the range from the melting point of the polymer to be kneaded to 60° C., preferably 50° C. higher than the melting point. This is because within this range, the polymer to be kneaded gels and the conductive particles can be uniformly dispersed.

When an additive is mixed into the PTC composition, the additive may be added either before or after premixing, before or after cross-mixing, or simultaneously with premixing or kneading.

PTC Element The PTC element of the present invention comprises a substance having the above-mentioned PTC characteristics and two or more electrodes in contact with the substance. The types of electrode materials that can be used here include metals that can be used as ordinary electrodes, such as nickel, cobalt, aluminum,
These include chromium, tin, copper, silver, iron (including iron alloys such as stainless steel), zinc, gold, lead, and platinum. It is desirable that the shape, dimensions, etc. of the electrodes be appropriately selected depending on the use of the PTC element. In this invention, as an electrode material,
In addition to rolled metal foil, annealed metal can also be used. Here, annealing is performed by heating the metal to a predetermined temperature and then slowly cooling it. Heating rate, heating temperature, heating time, heating atmosphere, cooling rate,
The annealing conditions such as the cooling atmosphere are appropriately selected depending on the material of the metal to be heat treated. This annealing removes stress, strain, etc. Additionally, the electrodes can be mechanically,
The surface may be electrochemically roughened, and a metal foil such as nickel having granular protrusions on the surface is particularly preferable.

Next, as an example of a method of joining a substance having PTC characteristics and an electrode in the present invention, the obtained substance having PTC characteristics is formed into a film shape, for example, and the substance having PTC characteristics is heated to around its melting point. , a method of forming a laminate by thermocompression bonding metal electrodes on the top and bottom of a film, PT
Heating a metal electrode to near the melting point of a substance having C characteristics,
There is a method in which the electrode is bonded under heat and pressure to the film to form a laminate, and an electrode plate and PTC are bonded using conductive adhesive.
There is a method of forming a laminate by bonding materials with specific properties. This laminate can be cut into a predetermined size to produce a substantially plate-shaped PTC element.

The present invention is characterized in that the PTC element is substantially plate-shaped, each electrode forms part or all of the end of the plate-shaped PTC element, and the distance α between the positive and negative electrodes as a pair is PT.
It is longer than the thickness β of the molded body of the material exhibiting characteristic C.

Embodiments of the PTC cord of the present invention will be described with reference to the accompanying drawings.

FIG. 1 shows one embodiment of a PTC element according to the present invention. The PTC element 1 of this embodiment has a rectangular plate shape as a whole and includes a pair of positive and negative electrodes 3a and 3b, and a plate-shaped molded body 2 made of a substance having PTC characteristics. These electrodes 3a and 3b form both end faces of the PTC element. This electrode interval α is longer than the thickness β of the PTC molded body.

FIG. 2 shows one embodiment of the PTC cord according to the present invention. The PTC element 1 of this embodiment has a rectangular plate shape as a whole and includes a pair of positive and negative electrodes 3a and 3b, and a plate-shaped molded body 2 made of a substance having PTC characteristics. These electrodes 3a and 3b form the ends of the same plane of the PTC element.

This electrode spacing α is longer than the thickness β of the PTC molded body.

FIG. 3 shows one embodiment of the PTC element according to the present invention. The PTC element 1 of this embodiment has a rectangular plate shape as a whole, and includes a pair of positive and negative electrodes 3a and 3b, a plate-shaped molded body 2 made of a substance having PTC characteristics, and a plate-shaped molded body 2 provided on a surface opposite to the electrode side. It consists of a metal plate 5.

The electrodes 3a and 3b form the coplanar ends of the PTC cord. This electrode spacing α is the thickness β of the PTC molded body.
The thickness of the electrode plate is shorter than the thickness β of the PTC molded body.

FIG. 4 shows one embodiment of the PTC element according to the present invention. The PTC element 1 of this embodiment has a rectangular plate shape with a square plane as a whole, and has a pair of positive and negative electrodes 3a and 3b, and a PTC element 1.
It consists of a plate-shaped molded body 2 made of a substance having characteristics. These electrodes 3a and 3b form the ends of the same plane of the PTC element.

Resin coating In the present invention, a resin film can be formed on the surface of the PTC element as necessary. Examples of such resins include epoxy resins, phenolic resins, polyethylene, polypropylene, polystyrene, polyvinyl chloride,
Polyvinyl acetate, polyvinyl alcohol, acrylic resin, fluororesin, polyamide resin, polycarbonate resin, polyacetal resin, polyalkylenoxide, saturated polyester resin, polyphenylene oxide, polysulfone, poly-p-xylene, polyimide, polyamideimide, polyesterimide, Polybenzimidacyl, polyphenylene sulfide, silicone resin, urea resin, melamine resin, furan resin, alkyd resin, unsaturated polyester resin, diallyl phthalate resin, polyurethane resin,
These include blended polymers, the above-mentioned resins modified by reaction with chemical reagents, radiation crosslinking, copolymerization, and the like.

Preferred resins among these resins are epoxy resins and phenol resins. Various additives such as plasticizers, curing agents, crosslinking agents, antioxidants, fillers, antistatic agents, flame retardants, etc. may be added to these resins. The resin used in this invention has at least insulating properties and has adhesiveness to the surface of the PTC element. The method of covering the resin is not particularly limited, and examples include spraying, painting,
This can be done by immersion, etc. Further, curing after coating the resin can be performed by chemical treatment, heating, radiation irradiation, etc. depending on the type of resin.

The obtained PTC element of the present invention can be used as a chip component.
It can be used for so-called surface mounting, a method of mounting components using only the surface of the substrate without providing holes in the substrate for passing component lead wires.

[Action and effect of the invention]

Since this invention is configured as described above, it has the following effects.

The PTC element of the present invention has a plate shape as a whole, the electrodes form the ends of the plate-shaped PTC element, and there is no lead plate or wire, so that the PTC element, which is a chip component, can be automatically supplied.
Automatic assembly becomes easy.

Furthermore, the thickness of the lead is not required, and the reduced thickness leaves more time in the dimensional design of the PTC element, for example, it can be made in accordance with leadless component standards, and it also has better PTC characteristics. devices can be manufactured.

In the PTC element of the present invention, the interval between the positive and negative electrodes forming a pair is longer than the thickness of the plate-shaped PTC molded body, and in the case of a horizontally long rectangular PTC element, preferably, the short side of the PTC element is shorter than the electrode interval, and the plate-shaped PTC molded body is Equal to or longer than body thickness. Due to these dimensions, the current flowing from the positive and negative electrodes flows uniformly depending on the PTC composition. That is, there is no place in the composition where current concentrates, and the device can stably exhibit PCT characteristics. Furthermore, the resistance value can be designed reliably.

〔Example〕

This invention will be specifically explained by way of example.

Example 1 A PTC composition having the following composition was prepared.

Weight% Polymer...High density polyethylene...
60 (manufactured by Toyo Soda, Nipolon Hard 5100) Conductive particles...carbon black 38 (manufactured by Cabot Corporation, Sterling V) Phenolic antioxidant 1
(Irganox 1010, manufactured by Ciba Geigy) These raw materials were kneaded with two rolls to prepare a substance having PTC characteristics, and further, a film with a thickness of 300 μm was formed using an extrusion molding machine or a roll molding machine. A PTC element as shown in FIG. 1 was manufactured by thermocompression bonding the roughened nickel electrodes to both ends of the film. This PTC element could be used for automated mounting.

Note that a resin film can also be formed on the surface of a molded article of a substance having PTC characteristics.

Example 2 The P
A TC element was manufactured. The obtained PTC element has the following characteristics compared to a PTC element in which a metal plate is not provided on the opposite side of the electrode.
It showed lower room temperature resistance.

[Brief explanation of the drawing]

FIG. 4 is a perspective view of an example of a PTC element according to the present invention, and FIG. 5 is an external view of an example of a conventional PTC element. 1...PTC element, 2...Substance having PTC characteristics, 3...Electrode, 4...Lead, 5...Metal plate applicant's agent Sato-O 2...PTC characteristics Substances with Figure 1 Figure 2 Figure 4 < a ) < b ) Figure 5

Claims (1)

[Claims] 1. A PTC element comprising at least two electrodes and a substance having PTC characteristics disposed between the electrodes and electrically connected to the electrodes, the PTC element as a whole comprising: A plate-shaped molding made of a material that is substantially plate-shaped, each of the electrodes forming a part or all of the end of the plate-shaped PTC element, and the distance between the pair of positive and negative electrodes having PTC characteristics. A PTC element characterized by being longer than the thickness of the body. 2. P according to claim 1, wherein each of the electrodes forms part or all of the side end surface of the plate-like PTC element.
TC element. 3. The PTC element according to claim 1, wherein each of the electrodes forms part or all of an end portion of the same plane of the plate-like PTC element. 4. Claim 3, wherein a conductive layer is formed on a surface opposite to the surface of the plate-like PTC element on which the electrode is provided.
The PTC element described in section. 5. The material having PTC properties comprises at least one polymer, electrically conductive particles dispersed in the polymer, and thermally conductive filler dispersed in the polymer. A PTC element according to any one of the first to fourth items.