JPS6338203A - Ptc device - Google Patents

Abstract

(57) [Abstract] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial Application Field) The present invention relates to an electrical resistance element, and more specifically, the property that electrical resistance rapidly increases in a relatively narrow temperature range with a warm stomach (P T C Characteristic (Positive temperature)
The present invention relates to a resistive element having an optical superposition (PTC element).

(Prior technology) The materials that make up PTC Thc
It can be used as a protection element that opens a short-circuited circuit using a heat-sensitive sensor υ, a dry battery, etc., and then closes the circuit once the short-circuit is removed. Therefore, the development of materials with PTC properties has been progressing for some time, and currently BaT! Examples include those in which a monovalent or trivalent metal oxide is added to 03, and those in which an S-electric substance is dispersed in a crystalline polymer such as polyethylene.

As shown in FIG.
, electrode plates 3a and 3b which sandwich the same, and lead plates (terminals) 4a and 4b connected to the electrode plates.

The manufacture of this PTC element is as follows.

A substance (composition) having PTC characteristics is first prepared, this PTC composition is formed into a film, and poles of ' and 43 are bonded to rolled nickel n on the upper and lower sides of the film to form a laminate. This one-layer body is cut to a predetermined size, and a lead plate is welded to the electrode surface of this laminated body with solder fU to manufacture a PTC element.

As shown in Figure 1, desirable characteristics for a PTC element are a high resistance value (peak resistance r2) at high temperatures and a low resistance value of 100 mΩ or less at room temperature (room temperature resistance r1).
It is to right 1. In order to lower the resistance at +i'', it is possible to increase the fit of carbon black (conductive particles) in the 1-CI+ composition.
It is not possible to obtain a sufficient P911 (pile/room temperature resistance ratio.) The contact resistance between the IC composition and the electrode, and the method for reducing the contact resistance between the electrode and the lead plate are weighed. No.Z has been proposed (U.S. Pat. No. 4,238,812 and Japanese Patent Application Laid-open No. 53-95298).

(Problems to be Solved by the Invention) When using a PTC element as a circuit protection element, room temperature resistance r is required to reduce electrical energy loss at room temperature.
1 is preferably as low as possible, particularly preferably 40 mΩ or less.

However, with conventional PTC elements, it is difficult to lower the room temperature resistance r1 while maintaining a sufficiently high peak resistance r2.

The present invention has been made based on the above-mentioned background, and its object is to provide a PTC element with a sufficient peak resistance/room temperature resistance ratio of .eta.-.

(Means for Solving the Problems) In order to achieve the above-mentioned objectives, the present inventors have conducted various tests and studies, and have found that high peak resistance mainly depends on the performance of the PTC material, while room temperature resistance We obtained the knowledge that it mainly depends on the contact resistance with the PTC material 71 electrode, and based on this knowledge, we investigated good electrode materials.We found that if a completely annealed soft metal foil was used for the Ti electrode, We have found that this invention is effective in achieving the object of the invention, and have completed the invention.

That is, l) T C element of this invention is P T C
1) A rolled IC element consisting of a substance having characteristics, an electrode sandwiching the substance and electrically connected to it, and an LC terminal electrically connected to the electrode, the electrode being completely annealed. The metal foil is, for example, Fl-rolled nickel, and is preferably characterized by having a thickness of 3 Q 71 m or more.

In a preferred embodiment of the present invention, the metal electrode can have a Vickers hardness of 75 to 9011 V.

Materials having l) T C properties that can be used in the present invention include, for example, mixtures of polymers and conductive particles. This polymer includes polyethylene, polyethylene oxide, 1-4-polybutadiene, polyT
Ethylene-ethyl acrylate, ethylene-ethyl acrylate-1
~ Co-copolymer, "Dylene-acrylic acid co-Φ polymer, PolyT-soul, polyamide, polyether, polycaprolactam, fluorinated ethylene-propylene copolymer, chlorinated polyethylene, chlorosulfonated ethylene, ethylene-
Vinyl acetate copolymer, polypropylene, borisdylene,
Styrene-acrylonitrile copolymer, polyvinyl chloride, polyvinylidene chloride, polyvinyl acetate, polycarbonate 1-, polyacetal, polyalkylene oxide, polyphenylene oxide, polysulfone, fluororesin, and blend polymers thereof, etc. have PTC properties. It can be used in the preparation of substances. type of polymer,
The composition ratio and the like can be changed as appropriate depending on desired performance, use, etc.

As the conductive particles dispersed in the ICS polymer, conductive substances such as carbon black, graphite, tin, silver, gold, and copper can be used.

In preparing a substance having PTC characteristics, in addition to the above-mentioned polymer and 1m particles, various additives may be added as necessary. Examples of substances that can be added include flame retardants such as antimony compounds, phosphorus compounds, chlorine compounds, and bromine compounds, and antioxidants.

In the present invention, the substance exhibiting PIG characteristics is prepared by mixing these raw materials, such as polymers, conductive particles, and other additives, in a predetermined ratio.

The laminate of the PTC element of the present invention is composed of electrode plates sandwiching a material C, such as the material having the PTC special bamboo mentioned above. The electrode plate that can be used here is a metal that can be used as a normal electrode, for example,
These include nickel, copper, silver, iron (including stainless steel), cobalt, zinc, aluminum, gold, chromium, tin, lead, and platinum.

One of the features of this invention is that the electrode is a fully annealed rolled metal foil. Here, annealing is carried out after heating the metal to a specified temperature.
This is done by slow cooling. The annealing conditions such as heating rate, heating temperature, heating time, heating atmosphere, cold IJ'I speed, and cooling atmosphere are selected to achieve complete annealing by appropriately changing them depending on the material of the metal electrode to be heat treated. This is because the electrode used in this invention preferably has a thickness of 30 μm or more. When a metal is completely annealed, stress, strain, etc. are removed, and the metal becomes comparatively softer. The hardness of the electrode used in this invention is 6 on Vickers hardness.
0 to 100 HV, preferably 75 to 90 HV. Having this hardness eliminates the stress relaxation of the foil caused by tripping and external heating, and also eliminates peeling from the resin due to warping of the electrodes.

The sandwiching method here includes a method of bonding the electrode plate and a substance having PTC characteristics using a conductive adhesive, a method of bonding the electrode plate and a substance having PTC characteristics,
There is a method of heating a substance having C characteristics to near its melting point and thermally pressing an i-electrode plate onto the material. Then the usual techniques,
A terminal such as a lead plate is electrically connected to the electrode by spot welding or the like.

A resin film can be formed on the surface of the PTC material of this invention if necessary. The types of resins that can be used in this invention are limited as long as they do not contradict the purpose of this invention. Examples of such resins include polyethylene,
Boria 1] Pyrene, polysretin, polyvinyl chloride, polyacid-resistant vinyl, polyvinyl alcohol, acrylic resin,
Fluororesin, polyamide resin, boria J-bonate resin, polyacetal resin, polyalkylene 71-1 site,
Saturated polyester resin, polynoenylene oxide, polysulfone, polyp-xylylene, polyimide, polyamideimide, polyamideimide, polybenzimidazole, borif nylene sulfide, silicon resin, phenol resin, urea resin, melamine resin, furan resin, alkyd resin , unsaturated polyester resins, diallyl chloride resins, epoxy resins, polyurethane resins, blend polymers thereof, reactions with chemical reagents, radioactive bridges [J,
Examples include modified resins such as copolymers. Among these, particularly preferred are epoxy resins and phenolic resins.

These resins contain various additives such as plasticizers, lubricants, crosslinking agents, vulcanizing agents, curing agents, and antioxidants.
- agents, ultraviolet absorbers, fillers, reinforcing agents, modifiers, antistatic agents, flame retardants, colorants, heat stabilizers, softeners,
Tackifier, binder, anti-tack agent, surface treatment agent, (=
1. Flavoring agents, antifungal agents, termite repellents, rat repellents, etc. may be added.

The resin that can be used in this invention has at least b insulating properties, and preferably has an electrode surface and a P
Adhesive to the surface of the TC material.

The method of coating the resin film is not particularly limited in this invention,
For example, spraying, painting, dipping in resin liquid, etc. The coating of the resin film is at least the PT that is not covered with the electrode.
It is preferable that the process be carried out on the surface of the C substance and also between the electrodes. However, other element surfaces may be coated.

Curing of the resin after coating 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 can be changed depending on the type of resin, the use and dimensions of the device, etc.

(Function) Since the present invention has the above-described configuration, it operates and functions as a P 1'C element as follows.

The metal electrode of the PTC element of this invention is a rolled metal foil that has been completely annealed. Since the heat-treated metal foil is pressure-bonded with the IC material,
1) The -I'C substance comes into close contact with the electrode surface, and its electrical contact resistance decreases.

When such a PTC element is used, for example, as a circuit protection element, if the circuit operates normally and the r/l current is normal, the room temperature resistance of In fact, there is almost no loss of electrical energy as dielectric heat. Others/J, If an excessive current flows due to a short circuit, it will rise and dry due to dicol heat, and the PT
C special f! 1, the resistance of the PC cord increases rapidly and the short circuit current substantially stops.

(Effects of the Invention) The PTC element of this invention provides the following effects! V can be done.

Since the electrodes of the PTC element of this invention are in close electrical contact with the PTC material, the contact resistance between the electrodes and the PTC material is small, which may cause thermal deterioration to the PTC material. Since no further processing is required, the peak resistance can be maintained. Therefore, it is possible to obtain a PTC ratio that provides a sufficient ratio of peak resistance to thirst resistance.

(Example) This invention will be explained more specifically by the following examples.

Fruit "L-kari"- A substance exhibiting the PTC properties of Juki Silk was prepared.

Primal 3460) Starling V) Additive Dioxide antiseptic agent 2U (Irganox 1010)
Two bottles of 'C were kneaded for 10 minutes using 1-Lumil. This 2
Molded to a thickness of tnm and cooled) Jl 112.20
X2! 'i Cut to 111111. 1 tnm
After cold rolling a normal carbon Ni plate with a thickness of 60 μm, it was annealed in ammonia decomposition gas at 600°C for 30 minutes. -1 completely annealed Ni foil (manufactured by intraosseous metal foil powder)
prepared.

In addition, this Ni foil passed the microhardness test stipulated in JIS Z2251.
It had a hardness of 0 Hv (0,05) and was -C.

A completely annealed Ni foil was cut into a size of 40 x 55 mm, a PTC composition was inserted between the edges, and the pieces were laminated and crimped using a hot press. This was cut into a size of 10.5×10.5#, and N1Pi leads (terminals) were electrically connected to the electrodes by a usual method such as spot welding.

The PTC cable according to this example has a room temperature resistance of 40 mΩ and a peak resistance of 1.2 kQ.

Comparative Example A comparative example was carried out in the same manner as in Example 1, except that a conventional non-annealed rolled Ni foil was used as the electrode.

The room temperature resistance of the PTC element with 1!1 is 70 mΩ.
child .

[Brief explanation of drawings]

FIG. 1 is a diagram showing PFC characteristics, and FIG. 2 is a perspective view showing an example of a PTC cord. 1... PTC element, 2... PTC composition, 3...
Electrode, 4... Lead plate.

Claims (1)

[Scope of Claims] 1. A PTC element consisting of a substance having PTC characteristics, electrodes sandwiching the substance and electrically connected to it, and terminals electrically connected to the electrode, wherein the electrode is A PTC element characterized in that it is a completely annealed rolled metal foil. 2. The PTC element according to claim 1, wherein the electrode has a thickness of 30 μm or more. 3. The PTC element according to claim 1 or 2, wherein the electrode is made of nickel. 4. The electrode has a Vickers hardness of 75 to 90 Hv.
PT according to claim 1, 2 or 3
C element.