JPS60196901A - Organic positive temperature coefficient thermistor - 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] It relates to a device with improved bonding strength with a metal plate.

7 Organic positive temperature coefficient thermistors are made by dispersing conductive powder such as carbon in a polymer such as polyethylene or polypropylene, and have positive resistance-temperature characteristics in which the resistance increases when a certain temperature is reached. Toshi C
Regarding this type of technology, for example, U.S. Pat. No. 3,591,526 and U.S. Pat.
There are numbers, etc.

Such organic thermistors include those in which a mesh metal is embedded in the element body and used as an electrode, and those in which a metal plate such as stainless steel is bonded to the surface of the element body and used as an electrode.

However, in the former case, although good ohmic contact can be obtained, there is a problem in that the overall resistance becomes high due to the specific resistance of the element body. Furthermore, in the latter case, the adhesion to the element body is poor, and when a life test is performed, the resistance value increases significantly, leaving problems in terms of practicality. Moreover, there was also the problem that the C metal plate would peel off due to a slight external force.

Therefore, this invention aims to solve the above-mentioned problems.It improves the bonding strength between the element body and the metal plate serving as the electrode, and also has a low resistance and excellent life characteristics. The present invention aims to provide an organic positive temperature coefficient thermistor.

That is, the gist of the present invention is to roughen the surface of an element that is in contact with the surface of the element and has a positive resistance-temperature characteristic, which is made of a polymer and conductive powder dispersed in the polymer. This is an organic positive temperature coefficient thermistor characterized by bonding metal plates and using them as electrodes.

Hereinafter, this invention will be explained in detail according to examples.

Example 88 parts of crystalline polyethylene and 12 parts of Ketjen black (carbon black) were thoroughly mixed to give a
After kneading at 0.degree. C., ozone (0,) was blown into the mixture at around 100'C to crosslink it.

The obtained crosslinked organic compound was molded into a plate shape with a thickness of +11A, and one side was roughened with an electrolyte on both sides of the element.
U foil (55 μm) was joined by hot pressing at 15[)° C. for 60 minutes to form an electrode. Thereafter, it was cut to a size of 11 angles, and a lead wire made of Cu was connected to the surface of the Cu foil by dipping in solder. Furthermore, the periphery was coated with epoxy resin (a sample was prepared).

The lead wire of the obtained sample was stretched, and the bonding strength between the electrode and the element was measured.As a comparison sample, one side was roughened with an electrolyte and a Cu foil without carbon was bonded to make an electrode. Regarding material C, the bonding strength was measured in the same way.

Table 1 shows the measurement results of daughter bonding strength. Table 1 As is clear from Table 1, the method according to the present invention roughens the metal plate and joins the C-containing EU foil. A bonding strength greater than that of the comparative sample was obtained, and ohmic properties were measured for each of the samples obtained in the above examples. Table 2 shows the measurement results.

The measurement method was to connect the terminals to the sample (u75) at 4 points and measure using the 4-terminal method.The distance between the terminals was ♂i. 1.
For reference, the specific resistance of the element body is also shown in °C.

As is clear from Table 2, the resistivity of the present invention is almost the same as that of the element body, indicating that good ohmic contact can be obtained.

Furthermore, a life test was conducted on each of the obtained samples, and the results are shown in Table 3.

Test 1 was to measure the change in resistance value when a voltage of 247 was applied for 100 hours.

Test 2 was 24VF) Voltage t, ON for 1 minute, 5
The change in resistance value was measured when the voltage was applied for 100 hours in a minute opy cycle.

Test 3 was to measure the change in resistance after being left at a temperature of 100''c- for 100 hours.

Test 4 was to measure the change in resistance after being left at a temperature of 120'C for 100 hours.

For comparison, the initial values of C for each test sample are combined and shown.

As is clear from Table 3, the product according to the present invention had a small rate of change in C in each life test, and had stable characteristics.

In addition, in the above-mentioned example, an example was explained in which Ccu foil was used as an electrode. As is clear from the description, according to the present invention, large bonding strength is obtained, good ohmic contact is exhibited, and C also exhibits stable characteristics in life tests. For example, when using the organic positive temperature coefficient thermistor according to the present invention as a heater, a sheet heater may be used as a heater.
We can supply products with no size restrictions. In addition, when using C for current limiting, the characteristics of high withstand voltage and low resistance can be fully utilized. For example, up until now, the limit of ceramic positive temperature coefficient thermistors was 0.2 fl, but now we can obtain resistance values as low as 1105 Ω, which can be used for current limiting and for multiple purposes. Murata Manufacturing Co., Ltd. Procedural Amendment (Voluntary) July z, 1981 1, Indication of the case 1982 Patent Application No. 52823 2, Name of the invention Organic Positive Characteristic Thermistor 3, Person making the amendment Relationship with Patent Applicant Address 2-26-10 Tenjin, Nagaokakyo City, Kyoto Prefecture Column 7 of "Detailed Description of the Invention" of the Specification, Contents of Amendment (1) Mei III 4, Page 4, Line 3 from the bottom "4-terminal method"
is corrected to "four-probe method."

that's all

Claims (1)

[Claims] A metal plate with a roughened surface in contact with the surface of the element is bonded to the surface of an element having positive resistance-temperature characteristics made of a polymer and conductive powder dispersed in the polymer, and this is used as an electrode. An organic positive temperature coefficient thermistor characterized by: