WO2021056751A1

WO2021056751A1 - Method for predicting service life of polystyrene material by using sun tracking concentration accelerated aging test

Info

Publication number: WO2021056751A1
Application number: PCT/CN2019/118274
Authority: WO
Inventors: 陶友季; 时宇; 揭敢新; 覃家祥
Original assignee: 中国电器科学研究院股份有限公司
Priority date: 2019-09-25
Filing date: 2019-11-14
Publication date: 2021-04-01
Also published as: CN110927050B; CN110927050A

Abstract

A method for predicting the service life of a polystyrene material by using a sun tracking concentration accelerated aging test, the method comprising: carrying out a sun tracking concentration accelerated aging test on a polystyrene (PS) material in any selected region; establishing an environmental severity model; on the basis of the environmental severity model, calculating an acceleration magnification of the sun tracking concentration accelerated aging test relative to the natural aging of the PS in an actual use region, and using said magnification to predict the service life of the PS material in the natural environment of the actual use region. The environmental severity model used in the present method may calculate the acceleration magnification of the accelerated aging test relative to any region. By means of carrying out one sun tracking concentration accelerated aging test on a PS material in any selected region, the service life of the PS material in any region may be predicted, which may effectively reduce the workload of the test and improve the accuracy of service life prediction.

Description

A method for predicting the service life of polystyrene materials by using sun-tracking concentrating accelerated aging test

Technical field

The invention relates to a test method for predicting the service life of a polystyrene material, in particular to a method for predicting the service life of a polystyrene material by using a sun tracking and concentrated accelerated aging test.

Background technique

As one of the five general plastics, polystyrene (PS) has the advantages of high rigidity, light weight, good fluidity, easy coloring, and good electrical insulation. It is widely used in outdoor products such as packaging, building materials, automobiles, and electronics.

In the past, the rapid prediction of the service life of PS materials was mainly achieved through artificial accelerated aging experiments. The test methods include accelerated aging of xenon lamps and accelerated aging of ultraviolet lamps. Although the artificial accelerated aging test has a short period and fast aging, there is a big difference between the artificial light source and the natural light spectrum. At the same time, it ignores the influence of factors such as the temperature difference between day and night, seasonal changes and air active components, and cannot completely and truly reflect the natural environment. For all the factors, sometimes the accelerated aging test has a low correlation with the natural aging test.

The solar tracking concentrating accelerated aging test uses a sun tracking concentrating device to condense the ultraviolet rays in the sunlight while increasing the test temperature of the sample. The purpose of the accelerated aging test is achieved by strengthening the ultraviolet radiation and temperature, and the acceleration rate is usually up to 8 to 10 times. Since the solar concentrating acceleration test directly uses the solar light source and is carried out in a natural environment, the test results have a good correlation with the actual service results. In addition, compared to the artificial accelerated test, the cost of the solar tracking concentrating accelerated aging test is lower than that of the xenon lamp test.

Therefore, based on the sun-tracking concentrated accelerated aging test, the establishment and development of the PS material service life prediction method, the accurate prediction of the service life of the material and its products, and the improvement of the selection of material formulations and the improvement of the aging resistance of the material have an important role .

Summary of the invention

The purpose of the present invention is to provide a method for predicting the service life of polystyrene materials by using the sun-tracking concentrating accelerated aging test to predict the service life of polystyrene materials in a natural environment in a certain area.

The above-mentioned object of the present invention is achieved by the following technical solution: a method for predicting the service life of polystyrene materials by using the sun tracking concentrating accelerated aging test, which is characterized in that the method is carried out in any selected area by using polystyrene materials. Sun tracking concentrated accelerated aging test, the establishment of environmental severity model, based on the environmental severity model to calculate the accelerated rate of solar tracking accelerated aging test relative to the natural aging of PS in the actual use area, used to predict the natural environment of the PS material in the actual use area Service life in the middle.

In the present invention, the steps for establishing the environmental severity model are as follows:

Step (1): Use the solar irradiance meter and temperature and humidity sensor installed on the solar tracking concentrating accelerated aging test device in the selected area to record the total surface of the sample rack of the solar tracking concentrating accelerated aging test device within a period of time. Solar ultraviolet radiation (denoted as Ir ₁ ), annual average temperature (denoted as T ₁ ), annual average relative humidity (denoted as RH ₁ );

Step (2): In the actual use area of the PS material (denoted as area A), monitor and analyze the long-term climate and environmental conditions of the area to obtain the main climate and environmental conditions that affect the aging of polymer materials in the area. The conditions include solar radiation, ambient temperature and relative humidity data, and the monitoring time is not less than 3 years; according to the monitoring data, record the total annual solar ultraviolet radiation in area A (denoted as I _rA ) and annual average temperature (denoted as T _A ), annual average relative humidity (RH _A );

Step (3): The model of the environmental severity model is shown in the following formula:

Where:

f _A is the environmental severity index;

T _f is the acceleration factor of the material for every 10°C increase in temperature, which is determined according to the type of material;

x is the effective solar radiation factor, which is determined according to the type of material;

y is the effective relative humidity factor, which is determined according to the type of material;

I _r1 is the total annual solar ultraviolet radiation in the solar tracking concentration accelerated aging test, the unit is megajoules per square meter (MJ/m ² );

RH ₁ is the annual average relative humidity in the solar tracking accelerated aging test;

T ₁ is the annual average temperature in the sun-tracking concentrated accelerated aging test, in degrees Celsius (℃);

I _rA is the total annual solar ultraviolet radiation of area A, in megajoules per square meter (MJ/m ² );

RH _A is the annual average relative humidity of area A;

T _A is the annual average temperature of area A, in degrees Celsius (℃);

For PS material, T _f =1.41, x=0.74, y=0.31, the model of the environmental severity model can be transformed into the following:

_{Substitute the values of I r1} , T ₁ , RH ₁ , I _rA , T _A , and RH _A recorded in step (1) and step (2) into equation 2, and calculate the value of environmental severity f _A , which is the sun Track the accelerated magnification of the concentrated light accelerated aging test relative to area A

_{The predicted PS service life (t A} ) in the actual use area according to the present invention is obtained by the following:

t _A ＝t ₁ ×f _A (Equation 3)

Where t ₁ is the failure time of PS in the solar tracking concentrated accelerated aging test in the selected area; f _A is the acceleration magnification of the solar tracking concentrated accelerated aging test relative to the actual use area.

The failure time of the above-mentioned PS in the selected area of the solar tracking concentration accelerated aging test of the present invention is obtained by the following steps:

Step (a): The PS sample is tested for the gloss retention of the sample before the test, and no less than N samples are tested. As a result, the arithmetic average of the N samples is taken and recorded as the initial performance value of the sample;

Step (b): Carry out the solar tracking concentrating accelerated aging test on the PS sample in the selected area, regularly test the light retention rate of the PS sample, and test no less than M samples each time, refer to the initial performance of step (a) Value to obtain the failure time (t ₁ ) of the PS sample, and the result is the arithmetic average of the M sample tests.

The above-mentioned step (b) of the present invention: Carry out the solar tracking concentration accelerated aging test on the PS sample, and the interval between each regular test does not exceed 240 hours; if the performance value of the PS is lower than 50% of the initial performance value during the regular test, Then the time of this regular test is the failure time of PS in the solar tracking concentrating accelerated aging test; the time of stopping the solar tracking concentrating accelerated aging test shall not be earlier than the failure time.

In the present invention, in the step (a), the PS sample is prepared according to the test requirements of the key performance to be investigated; for example, if the optical properties of the PS such as color difference or surface morphology change are observed, the PS sample is injection molded; The PS sample is a sample plate with a length, width and height of 60mm×80mm×3mm; if the mechanical properties of PS, such as tensile strength, are to be investigated, dumbbell-shaped and rectangular samples should be prepared according to relevant test standards; the key properties of the sample to be investigated before the test (Such as gloss retention or tensile strength) to test, test no less than 3 samples, that is, N is a natural number greater than or equal to 3.

In the present invention, in the step (1), the period of time is 10-12 months.

In the present invention, in the step (b), no less than 3 samples are periodically tested each time, that is, M is a natural number greater than or equal to 3.

Compared with the prior art, the present invention has the following remarkable effects:

(1) The sun-tracking concentrated accelerated aging test used in this method can effectively save test time compared with the ordinary natural aging test; compared with the xenon lamp accelerated aging test, it can obtain better correlation and improve service life prediction Accuracy;

(2) The environmental severity model used in this method can calculate the acceleration magnification of the accelerated aging test relative to any area. Through a solar tracking concentrating accelerated aging test of the PS material in any selected area, it can be predicted that the PS material will be in any area. The long service life can effectively reduce the test workload.

Description of the drawings

The present invention will be further described in detail below in conjunction with the drawings and specific embodiments.

Figure 1 is a graph showing the change in light retention rate of a PS sample in a solar tracking acceleration test carried out using the method of the present invention;

Figure 2 is a graph showing the change in light retention rate of PS samples in Phoenix in a natural exposure test carried out to examine the predicted service life of the present invention;

Fig. 3 is a graph showing the change in light retention rate of PS samples in Turpan in a natural exposure test carried out to examine the predicted service life of the present invention.

detailed description

Using the method of the present invention to predict the service life of PS materials in Phoenix, USA and Turpan, Xinjiang, the specific steps are as follows:

(1) Prepare the PS sample, then the PS sample is prepared by injection molding to a sample plate with a size of 60mm×80mm×3mm; the gloss retention of the sample is tested before the test, and 3 samples are tested. The result is the arithmetic of taking 3 samples to test The average value is recorded as the initial performance value of the sample;

(2) Carrying out a solar tracking concentrating accelerated test in Phoenix, the United States (as a selected area), and recording the total solar ultraviolet radiation on the surface of the sample holder of the solar tracking concentrating accelerated aging test device during the whole year of 2018 (I _r1 ), annual average temperature (T ₁ ), annual average relative humidity (RH ₁ ), the following results are obtained:

I _r1 ＝1271.03(MJ/m ² )

T ₁ ＝28.0(℃)

RH ₁ ＝31.7(%)

(3) Perform statistical analysis on the climate and environmental conditions carried out in Phoenix in the United States and Turpan in Xinjiang, and obtain the total annual solar ultraviolet radiation (denoted as _IrA ) and annual average temperature (denoted as T) in the above regions from 2016 to 2018. _A ), the annual average relative humidity (RH _A ) data, as shown in Table 1:

Table 1: Statistical analysis of climate and environmental conditions carried out in Phoenix, USA and Turpan, Xinjiang

(4) Carry out the accelerated solar tracking test of PS material in Phoenix, USA. The initial 60° angle gloss of the PS sample is tested before the start of the test. Every 240 hours (10 days) after the start of the test, the 60° angle gloss test of the PS sample is performed. The 60° angle gloss value of each test accounts for the initial The percentage of the data is the gloss retention of the sample. The change of the gloss retention of the PS sample with the extension of the test time is shown in Figure 1. Record the time when the light retention value of the PS sample drops to 50%, which is about 930 hours, then the failure time of the PS in the solar tracking concentrated accelerated aging test is 930 hours, that is, t ₁ =930h.

(5) Calculate the predicted service life of PS materials in Phoenix. Calculate the acceleration magnification of the solar tracking concentrating accelerated aging test relative to Phoenix (the test area is also used as the actual use area) according to formula 2, as shown below:

I _r1 ＝1271.03(MJ/m ² )

T ₁ ＝28.0(℃)

RH ₁ ＝31.7(%)

I _rA ＝316.49(MJ/m ² )

T _A ＝22.9(℃)

RH _A ＝31.7(%)

then

According to formula 3, the service life of PS in Phoenix is t _A =t ₁ ×f _A =930×3.33=3134h

Therefore, the predicted service life of PS in Phoenix is 3,097 hours, or about 129 days.

(6) Calculate the predicted service life of PS materials in Turpan (the actual use area). Calculate the acceleration magnification of the solar tracking concentrating accelerated aging test relative to Phoenix according to formula 2, as shown below:

I _r1 ＝1271.03(MJ/m ² )

T ₁ ＝28.0(℃)

RH ₁ ＝31.7(%)

I _rA ＝265.13(MJ/m ² )

T _A =17.5(℃)

RH _A ＝27.9(%)

then

According to formula 3, the service life of PS in Turfan is t _A =t ₁ ×f _A =930×4.84=4427h

Therefore, the predicted service life of PS in Turpan is 4427 hours, which is about 184.5 days.

(7) Check the calculated predicted service life by carrying out natural exposure tests. The natural exposure test of PS materials was carried out in Phoenix and Turpan. The initial 60° angle gloss of the PS samples were tested before the test, and the 60° angle gloss test of the PS samples was performed at intervals of 1 month after the start of the test. The percentage of the measured 60° angle gloss value to the initial data is the gloss retention of the sample. The change in the gloss retention of the PS sample in Phoenix with the extension of the test time is shown in Figure 2, and the change in the gloss retention of the PS sample in Turpan with the extension of the test time is shown in Figure 3.

According to the data in Figure 2, the time for the PS sample to fall to 50% in Phoenix is recorded, which is about 3220 hours. The actual failure time of PS in Phoenix is 3220 hours, which is very close to the predicted life of 3097 hours. The error is Only 3.81%. The general error within 5% indicates that the prediction accuracy is extremely high.

According to the data in Figure 3, the time for the PS sample to fall to 50% in Turpan is recorded, which is about 4600 hours. The actual failure time of PS in Phoenix is 4600 hours, which is very close to the predicted life of 4427 hours. The error is only 3.76%.

Therefore, the service life prediction accuracy of the PS material using the method of the present invention is relatively high.

The method for predicting the service life of the PS in Phoenix and Turpan in this embodiment can also be applied to predict the service life of the PS in any other region, and the method is the same as the foregoing embodiment.

The above-mentioned embodiments of the present invention do not limit the scope of protection of the present invention, and the embodiments of the present invention are not limited thereto. According to the above-mentioned content of the present invention, in accordance with common technical knowledge and conventional methods in the field, without departing from the present invention Under the premise of the above-mentioned basic technical ideas, other various modifications, substitutions or alterations made to the method of the present invention should fall within the protection scope of the present invention.

Claims

A method for predicting the service life of polystyrene materials by using the sun-tracking concentrated accelerated aging test, which is characterized in that the method establishes an environmental severity model by carrying out a solar-tracking concentrated accelerated aging test on polystyrene materials in any selected area , Based on the environmental severity model to calculate the accelerated magnification of the solar tracking accelerating aging test relative to the natural aging of the PS in the actual use area, which is used to predict the service life of the PS material in the natural environment of the actual use area.
The method for predicting the service life of polystyrene materials by using the sun tracking concentrated accelerated aging test according to claim 1, wherein the steps of establishing the environmental severity model are as follows:

Step (1): Use the solar irradiance meter and temperature and humidity sensor installed on the solar tracking concentrating accelerated aging test device in the selected area to record the total surface of the sample rack of the solar tracking concentrating accelerated aging test device within a period of time. Solar ultraviolet radiation (denoted as Ir 1 ), annual average temperature (denoted as T 1 ), annual average relative humidity (denoted as RH 1 );

Step (2): In the actual use area of the PS material (denoted as area A), monitor and analyze the long-term climate and environmental conditions of the area to obtain the solar radiation, environmental temperature and relative humidity that affect the aging of the polymer material in the area Data; According to the monitoring data, record the total annual solar ultraviolet radiation (recorded as I rA ), annual average temperature (recorded as T A ), and annual average relative humidity (RH A ) of area A;

Step (3): The environmental severity model is:

The value of f A is the acceleration magnification of the solar tracking concentrating accelerated aging test relative to the actual use area A.
The method for predicting the service life of polystyrene materials by using the solar tracking concentrating accelerated aging test according to claim 2, characterized in that: the predicted PS service life (t A ) in the actual use area is obtained by the following: t A = t 1 ×f A

Where t 1 is the failure time of PS in the solar tracking concentrated accelerated aging test in the selected area; f A is the acceleration magnification of the solar tracking concentrated accelerated aging test relative to the actual use area.
The method for predicting the service life of polystyrene materials by using the solar tracking concentrated accelerated aging test according to claim 3, wherein the failure time of the PS in the selected area solar tracking concentrated accelerated aging test passes the following Steps to get:

Step (a): The PS sample is tested for the gloss retention of the sample before the test, and no less than N samples are tested. As a result, the arithmetic average of the N samples is taken and recorded as the initial performance value of the sample;

Step (b): Carry out the solar tracking concentrating accelerated aging test on the PS sample in the selected area, regularly test the light retention rate of the PS sample, and test no less than M samples each time, refer to the initial performance value of step (a) In order to obtain the failure time (t 1 ) of the PS sample, the result is the arithmetic average of the M sample tests.
The method for predicting the service life of polystyrene materials by using the sun tracking concentrated accelerated aging test according to claim 4, characterized in that: in the step (a), N is a natural number greater than or equal to 3.
The method for predicting the service life of a polystyrene material by using a solar tracking concentrating accelerated aging test according to claim 2, characterized in that: in the step (1), the period of time is 10-12 months.
The method for predicting the service life of a polystyrene material by using a solar tracking concentrating accelerated aging test according to claim 4, characterized in that: in the step (b), M is a natural number greater than or equal to 3.
The method for predicting the service life of polystyrene materials by using the solar tracking concentrated accelerated aging test according to claim 4 or 7, characterized in that: in the step (b), the interval between each periodic test does not exceed 240 hours.
The method for predicting the service life of polystyrene materials by using the solar tracking concentrating accelerated aging test according to claim 8, characterized in that: in the step (b), if the performance value of PS is lower than the initial value during the periodical test 50% of the performance value, the period of the regular test is the failure time (t 1 ) of the PS in the solar tracking concentrated accelerated aging test; the time to stop the solar tracking concentrated accelerated aging test shall not be earlier than the failure time.
The method for predicting the service life of polystyrene materials by using the solar tracking concentrating accelerated aging test according to claim 2, characterized in that: in the step (2), the monitoring time is not less than 3 years.