JPH01110255A - Method and apparatus for measuring degree of rubber vulcanization by ultrasonic wave - Google Patents

Abstract

PURPOSE:To measure the degree of preceding in the vulcanization of rubber, by applying an ultrasonic wave to rubber fed with a fixed pressure to read a supply power to an ultrasonic vibrator necessary for keeping amplitude constant. CONSTITUTION:A rubber sample S is placed between a phone 3 for guiding an ultrasonic wave from an ultrasonic vibrator 2 and a pressure plate 8 of a pressurizing mechanism 7 to feed a fixed pressure thereto. An ultrasonic wave from the ultrasonic vibrator 2 is guided to the sample to detect amplitude thereof with an ultrasonic sensor 4. Then, A detection value from the sensor 4 is compared with a reference value previously set to control an output of a high frequency power source 1 with a control section 5 so that a deviation therebetween will be zero, that is, the amplitude of the ultrasonic wave is always at a fixed value. As a damping force of the rubber sample S relative to the ultrasonic wave is in a close relation with the degree of preceding in the vulcanization of the rubber, the degree of preceding in the vulcanization of the sample S can be measured by gauging a supply power to the ultrasonic vibrator 2 with a meter 6.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a method and apparatus for measuring the degree of vulcanization progress of rubber.

[Conventional technology]

Evaluation of the quality of rubber materials based on the vulcanization ability of rubber material vulcanization equipment and the variation in the degree of vulcanization progress of rubber (non-uniform vulcanization degree) has conventionally been carried out by the methods listed below.

a. Visual evaluation of the vulcanized rubber material (rubber product); Evaluation by physical property test such as tensile strength of the vulcanized rubber material (rubber product) C0 Immersion of the vulcanized rubber material (rubber product) Evaluation by deterioration tests such as tests [Problems to be solved by the invention] However, among the above, visual evaluation is not accurate because the judgment is influenced by subjectivity, and evaluation by physical property tests and deterioration tests In order to carry out this process, a large amount of data is required, and in addition, in order to evaluate the degree of non-uniform vulcanization within the same product, it is necessary to cut out many samples from within the product.

In addition, in physical property tests such as tensile strength, it may be necessary to set the sample to a certain size or shape, and for this reason, testing may not be possible depending on the object. Furthermore, deterioration tests have the problem of requiring a long time until test results are obtained.

In view of these problems, it is an object of the present invention to easily and accurately measure the degree of vulcanization progress and non-uniform vulcanization degree of rubber, and also to enable accurate measurement even with a small number of samples. That is.

[Means for solving problems]

That is, the present invention focuses on the fact that when the viscosity and elasticity of an object changes, the vibration attenuation rate of the ultrasonic waves propagating through the object also changes, and while applying ultrasonic waves to rubber under a constant pressure, It is characterized by keeping constant the amplitude attenuated by the vibration damping property that changes depending on the degree of progress of vulcanization of the rubber, and reading the power supplied to the ultrasonic oscillator necessary to keep the amplitude constant. A method for measuring the degree of rubber vulcanization using ultrasonic waves, a high-frequency power source that generates high-frequency power, an ultrasonic oscillator that generates ultrasonic waves depending on the way the high-frequency power is output, and an ultrasonic oscillator that is connected to the ultrasonic oscillator. and a horn that is brought into contact with the rubber sample, and control that controls the power to the ultrasonic oscillator based on the deviation between the detected value from the sensor that detects the amplitude of the ultrasonic wave and the set value to maintain the amplitude of the ultrasonic wave constant. The present invention provides an apparatus for measuring the degree of rubber vulcanization, characterized in that it has a pressurizing mechanism for applying a constant pressure to the rubber sample.

[For production]

When ultrasonic waves are applied to rubber under constant pressure conditions, the attenuation rate for the ultrasonic waves (vibrations) varies depending on the degree of progress of vulcanization (crosslinking) of the rubber, so the amplitude changes accordingly. Therefore, the power supplied to the ultrasonic oscillator required to maintain the amplitude of the ultrasonic wave at a preset constant value depends on the degree of progress of vulcanization, as shown in the graph of Figure 2. Change. Therefore, the measurement method of the present invention is as follows:
The degree of progress of vulcanization is evaluated by reading this supplied power, and if the pattern of the change is determined in advance, the degree of progress of vulcanization (x) of the rubber can be determined from the measured power value (y). can be easily found.

Furthermore, the measuring device of the present invention is based on the above-mentioned measuring method, and applies ultrasonic waves from an ultrasonic oscillator whose amplitude is controlled to be constant through a horn to a rubber sample to which a constant pressure condition is applied by a pressurizing section. This is to read the power supplied from the high-frequency power source necessary to keep the amplitude of the ultrasonic wave constant against the damping force (load) of the rubber sample.

〔Example〕

FIG. 1 shows an apparatus as an embodiment of the present invention.
(1) is a high frequency power source that generates high frequency power, (2) is an ultrasonic oscillator that generates ultrasonic waves by inputting the high frequency power from the high frequency power source (1), and (3) is a rubber oscillator that generates ultrasonic waves. A horn that guides (excites) waves to the sample (S), (4) an ultrasonic sensor that detects the amplitude of ultrasonic waves, and (5) the sensor (4)
A control unit that controls the output of the high-frequency power source (1) so that the detected value from the ultrasonic wave is compared with a preset reference value so that the deviation is zero, that is, the amplitude of the ultrasonic wave is always a constant value. , (8) is a meter or recorder that measures the power input from the high frequency power source (1) to the ultrasonic oscillator (2), and (7) is a pressure plate (8) facing the horn (3).
) and a pressurizing mechanism consisting of a hydraulic cylinder and a hydraulic circuit (not shown) connected thereto, and (8) is a base that supports the entire device.

The rubber sample (S) is the rubber product itself or a cut out of the rubber product whose degree of vulcanization is to be evaluated, and is placed between the horn (3) and the pressure plate (8) of the pressure mechanism (7). It is sandwiched and a constant pressure is applied. The ultrasonic wave generated by the ultrasonic oscillator (2) is applied to this sample (S) using the horn (3).
When the waves are guided through the ultrasonic oscillator (2), the power supplied to the ultrasonic oscillator (2) is controlled so that the amplitude of the ultrasonic waves is always constant. The power changes depending on the size. As already mentioned,
This damping force is closely related to the degree of vulcanization progress of the rubber, so for each type of rubber material, a master graph showing the relationship between power change and degree of vulcanization, as shown in Figure 2, is prepared in advance for physical property tests. If the vulcanization progress degree (X) is prepared by using the combination of the above and the like, the degree of vulcanization progress (X) can be easily determined from the measured power value (y).

〔Effect of the invention〕

As explained above, the method of the present invention focuses on the fact that the attenuation rate of ultrasonic waves varies depending on the degree of vulcanization progress of rubber, and the degree of vulcanization progress is controlled by changing the electric power to maintain the amplitude of the ultrasonic waves constant. When ultrasonic waves are applied to a rubber sample, changes in the power to the oscillator appear immediately, making measurement and evaluation possible in a short time. Since this is not necessary, the measurement is easy, and since the measurement is performed electrically, accurate measured values can be obtained. In addition to the above-mentioned effects, the device of the present invention can perform measurements simply and quickly by simply bringing the rubber sample into contact with the horn under constant pressure and propagating the ultrasonic waves, and the contact area between the sample and the horn can be By reducing , it is possible to take many measurement points, which has the effect of reducing the number of samples.

[Brief explanation of the drawing]

Fig. 1 is a schematic structural explanatory diagram showing a measuring device as an embodiment of the present invention, and Fig. 2 shows an example of the relationship between the degree of progress of vulcanization of rubber and the electric power value for keeping the amplitude of ultrasonic waves constant. This is a graph showing. (1) High frequency type 5 (2) Ultrasonic oscillator (3) Horn (4) Ultrasonic sensor (5) Control unit (e) Meter (7) Pressure mechanism (8) Pressure plate (8
) Base (S) Rubber sample

Claims (2)

[Claims] (1) While applying ultrasonic waves to the rubber under a certain pressure, the amplitude attenuated by the vibration damping property, which changes depending on the progress of vulcanization of the rubber, is kept constant. A method for measuring the degree of rubber vulcanization using ultrasonic waves, characterized by reading the power supplied to an ultrasonic oscillator required for (2) a high-frequency power source that generates high-frequency power; an ultrasonic oscillator that generates ultrasonic waves using the output from the high-frequency power source; a horn connected to the ultrasonic oscillator and brought into contact with the rubber sample; a control unit that controls power to the ultrasonic oscillator based on a deviation between a detection value from a sensor that detects the amplitude of the acoustic wave and a set value to maintain the amplitude of the ultrasonic wave constant;
A device for measuring the degree of rubber vulcanization, comprising a pressurizing mechanism that applies a constant pressure to the rubber sample.