JPS61274248A - Measurement for electric resistance of elastic material - Google Patents

Abstract

PURPOSE:To reduce the scattering of measured values noticeably, by measuring the electric resistance of an elastic material between electrodes after a specified electric energization period during which a electric energization property is made stable. CONSTITUTION:Measuring electrodes 12 are pressed on an elastic material 23 on an electrically insulating sample base 22 and press-bonded to make the elastic material 23 flow. Then, electric energization is started between the measuring electrodes 12, namely, a cylinder 13 and a rod 14 while the measurement of the electric energization period is started with a second timer 18. Then, when the electric energization reaches a specified tube, namely, as the electric energization property between the measuring electrodes 12 is made stable, the electric resistance R of a synthetic rubber blend 23 between the measuring electrodes 12 is measured with an electric resistance measuring device 19.

Description

Detailed Description of the Invention (Industrial Application Field) The present invention relates to a method for measuring the electrical resistance of elastic materials, for example, the dispersion state of fillers such as carbon black or metal particles in rubber is determined based on the physical properties of the rubber (for example, heat generation When the filler is a good electrical conductor such as carbon black or metal particles, the dispersion state of the filler is estimated.
This invention relates to a method for measuring electrical resistance of elastic materials for improving the formulation of rubber.

(Prior Art) Conventionally, as a method for measuring the electrical resistance of rubber in an unvulcanized state, there is a method described by Mr. B. B. Poonsta, Rubber Chemistry and Technology, Vol. 50, p. 194 (
(published in 1977).

This method consists of a cylindrical electrode and a rod-shaped electrode fixed at the center of the cylindrical electrode, and the cylindrical electrode and rod-shaped electrode are pressed into an unvulcanized rubber plate and the electrical resistance is immediately measured. be.

(Problems to be Solved by the Invention) However, this method of measuring electrical resistance is difficult because of the time dependence of electrical resistance due to the flow of unvulcanized rubber, that is, the electrical resistance changes over time, and No consideration was given to the time dependence of the electrical resistance of sulfur rubber itself. Therefore, when measuring the electrical resistance of unvulcanized rubber materials, etc., when an electrode is pressed into contact with an unvulcanized rubber plate, the unvulcanized rubber flows and deforms due to the pressing force, and the electrical resistance changes. There is a problem. This is because - To measure electrical resistance, the unvulcanized rubber must be in complete contact with the electrode, and due to the uneven shape of the surface of the unvulcanized rubber, surface resistance will occur if it is not in complete contact with the electrode. Therefore, the electrical resistance shows a time dependence that changes with time until the unvulcanized rubber is completely brought into close contact with the electrode. In addition, if a filler with good electrical conductivity is mixed in the unvulcanized rubber, the electrical resistance will be 1 even if the unvulcanized rubber and the electrode are in close contact with each other.
There is a problem in that it changes over time after starting 1i1. This is because there is a time dependency in which the amount of charge carriers due to polarization or the like changes over time on the surface of the filler when energized.

SUMMARY OF THE INVENTION Therefore, the present invention solves the above-mentioned problems when measuring electrical resistance, improves the reproducibility and accuracy of the measured value, and allows the measurement to be carried out continuously and automatically. An object of the present invention is to provide a method for measuring electrical resistance of an elastic material that can reduce time and improve measurement efficiency.

(Means for Solving the Problems) The electrical resistance measuring method according to the present invention includes pressing a cylindrical cylinder and a rod fixed inside the cylinder as measurement electrodes against an elastic material, and then pressing the cylinder. The predetermined pressing time is measured from the time when the and rod are pressed against the elastic material,
Next, after a predetermined pressing time, energization is started between the measurement electrodes, and a predetermined energization time is measured from the start of energization, and then, after a predetermined energization time, the electrical resistance of the elastic material between the electrodes is measured. It is characterized by the fact that it starts. Here, the "predetermined pressing time" refers to the period from when the measurement electrode comes into pressure contact with the elastic material until the elastic material undergoes fluid deformation and comes into complete contact with the measurement electrode.

Moreover, the "predetermined energization time" refers to the period from when energization is started between the electrodes until the energization characteristics become stable.

(Function) When the measuring electrode consisting of a cylinder and a rod descends and presses against the elastic material, measurement of the pressing time is started. Next, a predetermined pressing time is measured until the elastic material is fluidly deformed and the measurement electrodes are completely brought into close contact with each other. After this pressing time, energization is started between the measurement electrodes and measurement of the energization time is started. Next, after a predetermined energization time period until the energization characteristics become stable, the electrical resistance of the elastic material between the electrodes is measured and displayed.

(Example) Hereinafter, an example of the method for measuring electrical resistance of an elastic material according to the present invention will be described based on the drawings. 1 to 3 are diagrams showing an apparatus for carrying out the method for measuring electrical resistance of an elastic material according to the present invention, and FIG. 1 is an overall schematic diagram thereof.

In FIG. 1, reference numeral 1 denotes an electrical resistance measuring device for elastic materials, and the electrical resistance measuring device 1 is composed of a sample presser 2 and a measuring device 3. It is designed to automatically measure the electrical resistance of elastic materials.

A sample chamber 5 is provided on a lower pedestal 4 at the center of the sample presser 2 . An upper pedestal 7 is provided surrounding the sample chamber 5, and an air cylinder 8 is provided vertically on the upper pedestal 7. The air cylinder 8 has a piston 9 that can be vertically moved up and down by air from a high-pressure air tank (not shown), and the lower end of the piston 9 is provided with a flange portion 9a. The flange portion 9a is connected to a measurement electrode 12 via an electrically insulating plate 10, and the lower part of the measurement electrode 12 is inserted into the sample chamber 5. The measurement electrode 12 is the second
As shown in the figure, it is composed of a cylindrical cylinder 13 and a rod 14 fixed along the central axis of the cylinder 13. One end 16a of the lead wire 16 is connected to the upper part of the measurement electrode 12, and the other end 16b of the lead wire 16 is connected to the measuring device 3. The measuring device 3 is the first timer 17
, a second timer 18, an electrical resistance measuring device 19, and a printer 20.

2 and 3 are enlarged sectional views of essential parts of an apparatus for carrying out the method of the present invention, and FIG. 2 shows a measurement electrode 12 in pressure contact with an elastic material 23 on an electrically insulating sample stage 22. The figure showing the previous state, FIG. 3, is a figure showing a state in which the measuring electrode 12 is pressed against the elastic material 23 and then the elastic material 23 11 flows due to the pressure. As the elastic material 23, an unvulcanized synthetic rubber compound (in this example, 100 parts by weight of S B R1500 and 50 parts by weight of carbon black PHR) was used. The cylinder 13 and rod 14 of the measurement electrode 12 are insulated and supported by an electrical insulator 24, and a lead wire 16, a first timer 17, a second timer 18, and an electrical resistance measuring device 19 are connected to the upper end of the electrode 12. and conceptually illustrated.

Hereinafter, a method for measuring the electrical resistance of an elastic material according to the present invention will be explained using an electrical resistance measuring device 1.

FIG. 4 is a flowchart showing a program for measuring the electrical resistance of a synthetic rubber compound (elastic material) 23 by the method 1 for measuring electrical resistance of an elastic material according to the present invention.
~S indicates each step of the flow. This program is executed once for each measurement of the electrical resistance of one synthetic rubber compound 23.

First, air from a high-pressure air tank flows into the air cylinder 8 at Sl, and the cylinder 13 and rod 14 of the measurement electrode 12 connected to the lower end 9a of the piston 9 descend at a predetermined speed and come into pressure contact with the synthetic rubber compound 23. Then press this. Measurement of the pressing time is started by the first timer 17 at St, and a predetermined time T, ( 1 second to 10 minutes) (1 minute in this example). Next, at S, electricity is started to be applied between the measurement electrodes 12, that is, between the cylinder 13 and the rod 14, and the second timer 18 starts to measure the electricity application time. Next, in S4, the energization time is set to a predetermined time T.

(1 second to 10 minutes) (20 seconds in this example),
That is, when the current conduction characteristics between the measuring electrodes 12 are stabilized, the predetermined measuring means, that is, the synthetic rubber compound 2 between the measuring electrodes 12
The electrical resistance R of No. 3 is measured using an electrical resistance measuring device 19 (commonly available on the market). If a commercially available electrical resistance measuring device has a built-in energization time setting mechanism, it can be used. The measured electrical resistance R is then digitally displayed at S, or recorded on paper by a printer. One cycle of this program takes about 1 minute and 30 seconds.

Although not shown in the program, this program is continuously and automatically executed for each elastic material.

(Effects of the Invention) Next, the measuring method according to the present invention (Example) and the conventional measuring method (Comparative Example) were compared to confirm the effects of the present invention.

The above-mentioned embodiment is used for the method of measuring electrical resistance of elastic materials according to the present invention, and a general conventional measuring method is used for the conventional measuring method to improve measurement cycle time, measurement accuracy (variation), and reproducibility. compared gender.

The elastic material was made using the same synthetic rubber compound as in the example and having the same size. The measurement conditions and measurement results are shown in the table below.

(This page, blank spaces below) As shown in the measurement results in the previous table, the measurement cycle time in the example was reduced to about half that of the conventional measurement method (comparative example), and the measurement efficiency was greatly improved. are doing. Regarding the variation in measured values, the average measured value is 1500, and the standard deviation is 50 in the example and 2 in the comparative example.
90, the variation in measured values is significantly reduced, the accuracy is extremely improved, and the reproducibility is improved.

As explained above, according to the present invention, in measuring the electrical resistance of elastic materials, the measurement accuracy and reproducibility are significantly improved, the measurement cycle time is significantly shortened, and the measurement efficiency is significantly improved. are doing.

[Brief explanation of drawings]

FIGS. 1 to 3 are diagrams showing an embodiment of an apparatus for carrying out the method for measuring electrical resistance of an elastic material according to the present invention,
FIG. 1 is an overall schematic diagram, FIGS. 2 and 3 are enlarged cross-sectional views of essential parts, and FIG. 4 is a flowchart showing a program for implementing the method for measuring electrical resistance of an elastic material of the present invention. DESCRIPTION OF SYMBOLS 1... Electric resistance measuring device, 12... Measuring electrode, 13... Cylinder, 14... Rod, 23... Elastic material.

Claims (1)

[Claims] A cylindrical cylinder and a rod fixed inside the cylinder are brought into pressure contact with an elastic material as a measuring electrode, and then pressed.
A predetermined pressing time is measured from the time when the cylinder and the rod are pressed against the elastic material, and then, after the predetermined pressing time, energization is started between the measurement electrodes, and a predetermined energizing time is measured from the time when this energization starts. and then, after a predetermined energization time, measurement of the electrical resistance of the elastic material between the electrodes is started.