JPH0510903A - Automatic thermostability testing apparatus - Google Patents

Abstract

PURPOSE:To obtain the result of the test automatically and accurately without confirming the change in color of test paper during the test when the thermostability test of vinyl chloride resin is conducted. CONSTITUTION:A specified amount of a sample 5 of vinyl chloride resin is inputted into a test tube 4. A thermal-decomposition starting detector 6 wherein pulp is impregnated with glycerin is attached to the upper part of the test tube 4 with a plug 7. Thereafter, the test tube 4 is submerged into oil 3 that is heated to 180 deg.C in an oil well 2. The sample 5 is heated and thermally decomposed by submerging the test tube 4 into the oil well 2, and hydrochloric acid gas is generated. The generated hydrochloric gas reacts with water in the glycerin contained in the pulp, and the electric resistance between two electrodes 8 and 9 is remarkably decreased. Then, a voltage which is applied across two electrodes 8 and 9 is also decreased. The voltage drop is recorded in a recorder 14. The time of the voltage drop across two electrodes 8 and 9 is measured as the time when the thermal decomposition of the sample 5 is started.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a vinyl chloride resin thermal stability tester, and in particular, anyone can easily obtain accurate thermal stability test results without causing failure of the thermal stability test. The present invention relates to a thermal stability test device capable of

[0002]

2. Description of the Related Art Insulated electric wires, cables, etc. coated with synthetic resin have been increasing in number because of their good insulation performance. A vinyl chloride resin is mainly used as a synthetic resin used for insulating such electric wires and cables. Insulated electric wires, cables, etc. covered with such vinyl chloride resin are laid indoors and outdoors and are always in contact with the outside world. Therefore, the vinyl chloride-based resin with which the insulated wire, the cable, etc. are coated is exposed to the external environment during the extrusion coating and after the insulated wire, the cable, etc. are laid, and receives heat from the outside. By these heats, dehydrochlorination is generated and decomposed, and the vinyl chloride resin is deteriorated and, in extreme cases, is broken into pieces. Deterioration of vinyl chloride resin
Reduces insulation. Therefore, the vinyl chloride resin is required to have so-called thermal stability that maintains a stable state even at a high temperature to some extent.

The thermal stability of a vinyl chloride resin is measured by the time from the exposure of the vinyl chloride resin at a constant temperature (for example, 180 ° C.) to the thermal decomposition to generate hydrochloric acid gas. Therefore, the thermal stability test of vinyl chloride resin is
It is performed by exposing the sample vinyl chloride resin piece to a constant temperature and then measuring the time from the thermal decomposition of the sample to the generation of hydrochloric acid gas.

Therefore, conventionally, a vinyl chloride resin thermal stability test has been carried out by a vinyl chloride resin thermal stability tester as shown in FIG. That is, 2 g of a vinyl chloride resin sample 110 to be tested is weighed and placed in the test tube 100. Then, the red Congo red test paper 120 soaked with glycerin is attached to the cotton plug 130 so that the tip of the Congo red test paper 120 is separated from the bottom of the test tube 100 by a predetermined distance (about 10 cm is appropriate). Attach to. After that, the test tube 100 is immersed in an oil tank 150 containing the oil 140 heated to 180 ° C. When the test tube 100 is immersed in the oil tank 150, the oil tank 15
When the sample 110 is heated by the heat of the oil 140 in 0 and the sample 110 is thermally decomposed, the color of the Congo red test paper 120 eventually changes from red to blue. The person conducting the thermal stability test of the vinyl chloride resin observes the color change of the Congo red test paper 120 during the thermal stability test of the vinyl chloride resin, and the color of the Congo red test paper 120 changes from red to blue. Change. The time from when the test tube 100 was dipped in the oil tank 150 to when the color of the Congo red test paper 120 changed from red to blue was measured to measure the thermal stability of the vinyl chloride resin.

[0005]

Those who conduct the thermal stability test of the vinyl chloride resin in this manner observe the color change of the Congo red test paper 120 during the thermal stability test of the vinyl chloride resin. Since the time when the color of the Congo red test paper 120 changes from red to blue is recorded to measure the thermal stability of the vinyl chloride resin, the Congo red test is performed during the thermal stability test of the vinyl chloride resin. Keep an eye on the paper 120 or, during the thermal stability test of the vinyl chloride resin, periodically look at the Congo Red test paper 120 and periodically observe the color change of the Congo Red test paper 120. Was.

Therefore, when the Congo Red test paper 120 is observed without fail during the thermal stability test of the vinyl chloride resin, no other work can be performed during the thermal stability test of the vinyl chloride resin. During the heat stability test of the vinyl chloride resin, if the eye of the Congo red test paper 120 is regularly turned on and the color change of the Congo red test paper 120 is regularly observed, the heat stability of the vinyl chloride resin will be improved. It was very troublesome to check that the color of the Congo red test paper 120 changed from red to blue during the sexuality test, and it was very troublesome. If the color of the Congo red test paper 120 changed from red to blue, If the time cannot be observed, a retest must be carried out, and in the case of the retest, there is a problem that it takes a considerable time for the heat stability test of the vinyl chloride resin again.

The present invention is an automatic thermal stability tester capable of automatically and accurately obtaining test results during a thermal stability test of a vinyl chloride resin without confirming a change in color of a test paper during the test. Is intended to provide.

[0008]

In order to achieve the above object, in a vinyl chloride resin thermal stability test apparatus of the present invention, an oil tank capable of heating oil to a predetermined temperature and a sample is inserted and held. A test tube, a stopper for sealing the inlet of the test tube, two electrodes supported by the stopper at a predetermined distance, and two electrodes at the tips of the two electrodes. The sample inserted into the test tube is heated to a predetermined temperature by heating the oil in the oil tank to a predetermined temperature, and the heat of the sample changes due to the change in electric resistance of the infiltrant that changes with the gas generated from the sample. The decomposition start time is measured.

[0009]

[Function] Put a predetermined amount of vinyl chloride resin sample in a test tube. Then, a pyrolysis start detector in which glycerin is dipped in pulp is attached to the upper part of the test tube by a stopper. Then, the test tube is immersed in oil heated to 180 ° C. in an oil bath. By immersing the test tube in this oil tank, the sample is heated and pyrolyzed to generate hydrochloric acid gas. The generated hydrochloric acid gas reacts with the water in the glycerin contained in the pulp, and significantly reduces the electric resistance between the two electrodes. Then, the voltage applied between the two electrodes also drops, and this voltage drop is recorded in the recorder. The time when the voltage between the two electrodes drops is measured as the time when the thermal decomposition of the sample starts.

[0010]

EXAMPLES Examples of the thermal stability test apparatus for vinyl chloride resin according to the present invention will be described below. 1 to 4 show an example of a vinyl chloride resin thermal stability test apparatus.

In the figure, reference numeral 1 is a thermal stability tester for testing the thermal stability of vinyl chloride resin. An oil tank 2 stores oil 3 therein, and the oil tank 2 can heat the oil 3 to a predetermined temperature (about 180 ° C.). Reference numeral 4 is a test tube, and 5 is a sample of a vinyl chloride resin piece put in the test tube 4. When this sample 5 is heated to a predetermined temperature (about 180 ° C.) by the oil 3 in the oil tank 2, it thermally decomposes to generate hydrochloric acid gas.

Reference numeral 6 denotes a pyrolysis start detector, which automatically detects the time when the sample 5 placed in the test tube 4 is heated by the oil 3 in the oil tank 2 and starts pyrolysis. The thermal decomposition start detector 6 is attached to the upper part of the test tube 4 by a stopper 7. The plug 7 is made of cotton, for example. Electrodes 8 and 9 are made of copper wire, and the electrodes 8 and 9 are attached through the stopper 7. Further, the electrode 8 and the electrode 9 are wound with the pulp 10 separated from each other for a predetermined period so as not to contact each other. Reference numeral 11 is a paper, which is attached to the pulp 10 in contact with the electrodes 8 and 9. This pulp 10 can contain glycerin as an infiltrant, and when it contains this glycerin, it maintains a certain electric resistance.

Lead wires 12 and 13 are connected to the electrodes 8 and 9 and are connected to the recorder 14. A constant voltage is applied between the electrodes 8 and 9 via the lead wires 12 and 13. By applying a constant voltage to the lead wires 12 and 13, the recorder 14 detects the electric resistance value of the pulp 10 containing glycerin. Therefore, the electric resistance value between the electrode 8 and the electrode 9,
That is, when the electric resistance value of the pulp 10 changes, the recorder 14 detects the changed time.

Next, the operation of this embodiment will be described.
First, 2 g of a sample 5 of vinyl chloride resin to be tested is weighed and put in the test tube 4. Then, the pyrolysis start detector 6 in which glycerin is dipped in the pulp 10 is attached to the upper part of the test tube 4 by the plug 7. At this time, the tip of the pulp 10 is installed so as to be separated from the bottom of the test tube 4 by a predetermined distance (about 10 cm). After that, the test tube 4 is immersed in the oil 3 heated to 180 ° C. in the oil tank 2. When the test tube 4 is dipped in the oil tank 2, the sample 5 is heated and thermally decomposed by the heat of the oil 3 in the oil tank 2, and the sample 5 generates hydrochloric acid gas. Then,
The generated hydrochloric acid gas is absorbed in glycerin and reacts with water (10% to 20%) contained in glycerin, and the electrode 8
The electric resistance of the pulp 10 between the electrode 9 and the electrode 9 is significantly reduced. Then, the voltage applied between the electrode 8 and the electrode 9 decreases in synchronization with the decrease in the electric resistance value of the pulp 10. The recorder 14 records this voltage drop. That is, the time when the voltage between the electrodes 8 and 9 drops is the time when the thermal decomposition of the sample 5 starts. Therefore, if the recording paper is flowed through the recorder 14 for a certain period of time from the start of the test, the reaction start time of the thermal decomposition of the vinyl chloride resin becomes clear and the accurate value at the start of thermal decomposition can be known.

[0015]

EFFECTS OF THE INVENTION Since the present invention is constructed as described above, it is not necessary to constantly check the change in the color of the test paper during the thermal stability test of the vinyl chloride resin, and the chloride An accurate measured value of the thermal stability of vinyl resin can be automatically obtained.

[Brief description of drawings]

FIG. 1 is an overall configuration diagram showing an embodiment of a vinyl chloride resin thermal stability test apparatus according to the present invention.

FIG. 2 is an enlarged view of the sample container shown in FIG.

3 is an enlarged view of the thermal decomposition start detector shown in FIG. 1. FIG.

4 is a cross-sectional view of the thermal decomposition start detector shown in FIG.

FIG. 5 is a continuous operation diagram showing a conventional thermal stability test method for vinyl chloride resin.

[Explanation of symbols]

 1 ………………………………………… Thermal stability tester 2 …………………………………… Oil tank 3 ………………………………… … Oil 4 ………………………………………… Test tube 5 …………………………………… Sample 6 …………………………………… Pyrolysis start detector 7 ………………………………………… Plug 8,9 ……………………………… Electrode 10 …………………………………… … Pulp 14 …………………………………… Recorder

Claims (1)

Claim: What is claimed is: 1. An oil tank capable of heating oil to a predetermined temperature, a test tube for inserting and holding a sample, a stopper for sealing the inlet of the test tube, and a predetermined stopper for the stopper. Sample inserted into the above test tube, which is composed of two electrodes supported at a distance and an infiltrant in which the tips of the two electrodes are wrapped around the two electrodes and impregnated with glycerin An automatic thermal stability test apparatus, wherein the thermal decomposition start time of the sample is measured by heating the oil in the oil tank to a predetermined temperature and changing the electric resistance of the infiltrant that changes depending on the gas generated from the sample.