JPS6183947A - Evaluation of deterioration of high-molecular material - Google Patents

Abstract

PURPOSE:To effect rapid and accurate evaluation of a high-molecular material, by irradiating a beam of light to a specimen while gas containing oxygen is allowed to flow and measuring, with an electronic spin resonance apparatus, a radical amount generated by oxidization of the specimen. CONSTITUTION:A quartz glass tube 3 transmitting temperature controlled air penetrates through a hollow resonator 1 and a quartz test specimen tube 5 containing a specimen 4 is inserted inside. Oxygen gas generated by an oxygen pump 9 is fed to a pump 10 for proper pressurization and the gas is led to the tube 5 through a gas tube 11 to be blown to a surface of the specimen 4. Further, an ultraviolet ray emitted from a source 6 of ultraviolet rays is admitted into a hollow resonator 1 through lens 7 and light inlet port 8 for projection onto the specimen 4. Thus, by measuring a radical amount generated by oxidation of the specimen 4 by an electronic spin resonator, rapid and accurate evaluation of a high-molecular material can be performed.

Description

Detailed Description of the Invention [Field of Industrial Application] The present invention relates to a method for evaluating the deterioration of polymeric materials such as polyurethane resins in a short time using an electron spin resonance apparatus (ESR apparatus). It is something.

[Prior Art] Eight-molecular materials are widely used in daily life, but weather resistance is particularly required for those used outdoors.
Progress is being made in developing and improving materials with excellent weather resistance. Conventionally, a sunshine weatherometer, an ultraviolet carbon weatherometer, and the like have been used to evaluate weather resistance. These devices expose the material to a specified temperature and humidity and irradiate it with ultraviolet rays or light similar to natural light to degrade the material. After a specified period of time, the material surface changes in color, gloss, or strength. [Problem to be solved by the invention] However, the conventional evaluation method using a sea urchin 1F meter takes hundreds to thousands of hours. Evaluation could not be carried out until the time had passed, which was a major reason why it took a long time to develop and improve materials.

The present invention has been made in view of the above-mentioned conventional problems, and it is an object of the present invention to provide a method that can accurately evaluate materials in a short time.

[Means for Solving the Problem] In order to achieve this object, the present invention irradiates a test sample with light in a state where a gas containing oxygen flows, and reduces the amount of radicals generated when the test sample is oxidized. is characterized in that it is measured by an ESR resonance device.

[Beginning of the invention] Oxidative deterioration accounts for a large proportion of the deterioration of polymeric materials, and the mechanism for this is, for example, as shown in the following formula: i' (
It is thought that l-1) is removed by long-term ultraviolet irradiation, temperature changes, etc., and oxygen (02) is bonded thereto.

P H-→P・→POO・ POO・ in Formula 11 is a radical (Ti group 1), and from this reaction formula, it can be seen that the Φ of the radical increases as the oxidation reaction progresses and deterioration progresses. Therefore, the present inventor measured the amount of radicals in polymer materials (polyurethane resins) A and B that had been degraded using a conventional Wenaometer using L and S RR settings.

FIG. 2 is a diagram showing the measurement results using a weatherometer, with the horizontal axis representing the deterioration time and the vertical axis representing the amount of radicals.

From this figure, it was confirmed that the amount of radicals m increases as time passes, and that the curve of increase in the amount of radicals matches the deterioration progression curve known from conventional gloss and physical property tests.

In this way, it has been found that it is possible to accurately determine the degree of material deterioration by measuring the amount of radicals using an ESR device, but there is no difference in the deterioration time measured by a diode meter. However, as it is, it still takes a long time to perform an evaluation.

Therefore, the inventor of the present invention repeatedly considered and experimented in search of a method to shorten the deterioration time, and found that by irradiating the test sample with light while oxygen-containing gas is flowing, the test sample is oxidized and produced. By measuring the amount of radicals using an ESR device, it is possible to dramatically shorten the time required for evaluation from the conventional hundreds to thousands of hours to several minutes to several tens of minutes. I found it. Examples and test examples of the present invention are shown below.

[Example] FIG. 1 shows a cross-sectional view of essential parts of a HSR device used to implement the method according to the present invention. In the figure, reference numeral '1 denotes an empty 1/1 co-container to which microwaves are supplied from the waveguide 2, and is placed in a uniform static magnetic field in a direction perpendicular to the plane of the paper. A quartz glass tube 3 through which temperature-controlled air passes passes through the cavity resonator 1, and a quartz sample tube 5 containing a test sample 4 is inserted into the tube. 6 is an ultraviolet light source, the generated ultraviolet light is introduced into the cavity resonator 1 through a lens 7 and a light entrance 8, and is irradiated onto the sample 4. 9 is an oxygen cylinder, and the generated oxygen gas is pumped 10, where appropriate pressure is applied, and guided into the sample tube 5 through the air pipe 11, where it is blown onto the surface of the sample.M blown into the sample tube 5
The elementary gas is discharged from the exhaust port 13 located in the collar 12 of the sample tube 5.
is discharged to the outside through the 14 is a blower for sending air to the glass tube 3, 15 is a temperature controller 11i1 for adjusting the temperature of the air, and 16 is an exhaust port.

Test example 1 Test sample: 2 mmx 2 m1nx 30+11
Prepare polyurethane resins A and B (the same as those used in the experiment shown in Figure 2 earlier) with a size of 111, and put them in sample tube 5.
The ESR spectrum was measured 11 times in 26 minutes at appropriate time intervals while blowing oxygen gas and irradiating with ultraviolet rays at a temperature of 60°C. Figure 3 shows the ESR spectra S1 to S311 obtained in 11 measurements for sample A.
+i t) I-i's. Signal 1 (signal 1 in the spectrum is from the standard sample, and the three signals Ul, tJ2, and tJ3 are signals due to No radicals generated by the oxidation reaction. As time passes, the intensity of the signal jJ1.U2゜U3 increases, and the amount of radicals increases. increases, indicating that deterioration is progressing.

Figure 4 plots the change in the relative intensity of signal U2 (the ratio of the peak-to-peak value of U2 to the constant peak-to-peak value of signal R of the standard sample) in the ESR spectrum obtained in this way. This is what I did. Comparing this FIG. 4 with FIG. 2 described above, it can be seen that both show almost the same changes. Conventionally, this would be 3
According to the present invention, it is possible to obtain approximately the same amount of adhesive as that obtained at 00 hours (deterioration l! 'l I!7) by spraying oxygen gas for only 26 minutes and by measuring while irradiating ultraviolet rays. This shows that the time required for evaluation can be reduced by an order of magnitude.

Test Example 2 The oxygen gas cylinder 'gArf in FIG. Prepare B, put it in sample tube 5, and set it to temperature 2.
ESR measurements were performed 11 times in 26 minutes at appropriate time intervals while blowing air and irradiating ultraviolet rays at 5°C.
An ESR spectrum similar to that shown in FIG. 3 was obtained.

Figure 5 shows the E obtained in this way, similar to Figure 4.
The change in relative intensity of signal U2 in the SR spectrum is plotted. Comparing Figure 5 and Figure 4, we can see that due to the difference in acid depth contained in the blown gas,
Although the separation between the curve for the sample and the curve for sample B is somewhat reduced in FIG. 5, it can be seen that the two curves show approximately the same changes in both figures. Therefore, in Test Example 2 in which air was blown, by slightly extending the measurement period, it is possible to obtain data in which the curve for the sample and the curve for Sample B are sufficiently separated, as in Measurement Example 1.

FIG. 6 is a graph showing the improvement process of polyurethane resin C measured on the same strip f1 as in Test Example 1. In FIG. 6, curve C1 is the measurement result for the first manufactured one, and curve C2,03 is the measurement result for the one obtained by improving the ingredients and manufacturing method based on the result. Naturally, the curve C3, which exhibits slow deterioration, is adopted, and according to the present invention, the convex molecule 44FI can be evaluated accurately in a very short time, so it is possible to make such improvements and develop better materials. can be done in a short period of time.

It goes without saying that the present invention is applicable not only to polyurethane resins but also to all polymeric materials that generate radicals through oxidation.

Effect 1 of the Invention As detailed above, according to the present invention, polymer materials can be evaluated accurately in a short time.

[Brief explanation of the drawing]

Fig. 1 is a plan view of the main parts of the ESR device d for carrying out the method according to the present invention, and Fig. 2 is for test samples A and B degraded by a conventional weatherometer. Fig. 3 shows the ESR spectra obtained in 11 measurements for sample △ using the same sample. - Figure 4 is a diagram plotting the change in relative intensity of Signol U2 in the ESR spectrum obtained in the 11 measurements in Test Example 1, Figure 5 is a diagram recorded on the test example. Figure 6 is a graph plotting the change in relative intensity of signal U2 in the ESR spectrum obtained in 11 measurements in Example 2, and shows the improvement process of polyurethane resin C measured under the same conditions as Test Example 1. be. 1: Cavity resonator 2: Waveguide

Claims (2)

[Claims] (1) A polymer material characterized by irradiating a test sample with light in a state where a gas containing oxygen is flowing, and measuring the amount of radicals generated when the test sample is oxidized using an electron spin resonance device. Deterioration evaluation method. (2) The evaluation method according to claim 1, wherein the light is ultraviolet light.