Test method for fluorescent ultraviolet lamp of th

2022-08-01
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Vulcanized rubber artificial climate aging (fluorescent ultraviolet lamp) test method

1 scope

this standard specifies an artificial climate aging test method that simulates the aging factors such as solar ultraviolet light, temperature and condensed water of natural climate with fluorescent ultraviolet lamp and condensing device

this standard is applicable to the weather resistance test of vulcanized rubber exposed under the alternating conditions of ultraviolet light and condensation

2 reference standard

the provisions contained in the following standards constitute provisions of this standard through reference in this standard. At the time of publication of this standard, the editions shown are valid. All standards will be revised. Parties using this standard should explore the possibility of using the latest editions of the following standards

gb grey scale for assessing discoloration (IDT ISO 105 a02:1984)

gb/t vulcanized rubber and thermoplastic rubber Determination of tensile properties

gb standard for colour fastness to light and climate blue wool (IDT ISO 105 b:1984)

gb standard temperature for environmental conditioning and testing of rubber samples Humidity and time (EQV ISO 471:1983 ISO 1826:1981)

gb/t 9865. preparation of samples and specimens of vulcanized or thermoplastic rubber part 1: physical tests (IDT iso:1986)

gb/t vulcanized rubber artificial climate (xenon lamp) aging test method (NEQ ISO: 1987)

gb/t vulcanized rubber test method for resistance to sunlight exposure under glass (NEQ ISO: 1985)

3 method summary

vulcanized rubber exposed to ultraviolet light In the environment of aging factors such as temperature and condensation, the change of sample performance shall be detected within the specified time, so as to evaluate the weatherability of vulcanized rubber

4 test device

4.1 test chamber

the test chamber studio is equipped with two rows of four fluorescent lamps in each row, and is equipped with a heating water tank, a sample rack, a blackboard thermometer, and a device to control and indicate the working time and temperature

4.2 fluorescent lamps

fluorescent lamps are divided into five types: UV-A, UV-B, UV-C, uv-d and uv-e. the maximum peak radiation wavelengths of various types of fluorescent lamps are different. Unless otherwise specified, UV-B lamps are generally used. The energy output of fluorescent light gradually declines with the service time 140 the UPVC pipe fittings for building drainage are reduced. In order to reduce the impact of fluorescent energy decay on the test, a new lamp is replaced by an old lamp every 1/4 of the service life of the 8 fluorescent lamps. Other position changes are shown in Figure 1, so that the fluorescent lamps are replaced regularly in sequence. In this way, the UV light source is always composed of new lamps and old lamps, and a constant output light energy is obtained

4.3 sample rack

the sample rack is composed of frame base frame, backing plate and extension spring. The frame base frame and backing plate are made of aluminum alloy material

4.4 blackboard thermometer × 10㎜ × 2.5mm black aluminum plate is connected to the temperature sensor. It should be within the exposure center so that it reflects the test temperature as much as possible

4.5 instrument and reference material for measuring radiation quantity

according to conditions and needs, the radiation quantity meter or reference material can be selected to measure the light energy received by the sample

4.5.1 radiometer

the radiometer has an integrating illuminometer and a radiometer

4.5.2 the reference material

blue wool standard shall comply with the relevant provisions of GB 730; The grey standard sample card shall comply with the relevant provisions of GB 250

5 sample

5.1 the sample shall be prepared in accordance with the relevant provisions of gb/t 9865

5.2 the shape and specification of the sample shall be determined according to the evaluation index and the requirements of the corresponding test standards. For example, the sample for testing tensile properties shall be in accordance with the provisions of gb/t 528

5.3 the number of samples shall be determined according to the number of test items. Generally, the number of effective samples for each test shall not be less than 3

5.4 the sample for measuring the color change shall comply with the provisions of 6.2 in gb/t 12831

6 test conditions

6.1 the test cycle time is generally specified as 4H UV exposure followed by 4H condensation. If necessary, it can be exposed to ultraviolet light for 8h and then condensed for 4H

6.2 the UV exposure temperature is generally specified as (50 ± 3) ℃. (60 ± 3) ℃ or other temperatures can be selected according to the characteristics of the material and the application environment

6.3 the condensation temperature is generally specified as (50 ± 3) ℃

6.4 during UV exposure, the equilibrium temperature of the test chamber supplied with hot air should be kept within ± 3 ℃

6.5 during condensation exposure, the equilibrium temperature of hot water in the water tank shall be kept within ± 3 ℃

6.6 distilled water, deionized water or potable tap water can be used for water supply to the tank

6.7 the nearest distance between the sample surface and the lamp plane is 50mm and parallel

6.8 the irradiance in the 280 ~ 400nm wavelength range accepted by the sample surface shall not be greater than 50w/㎡, and there shall be no radiation lower than 270nm wavelength

6.9 in order to facilitate the inspection and end of the test, the exposure test time is generally specified as the multiple of 24h, 7d or 7d

7 test process

7.1 sample installation

the sample is installed on the sample rack in a free state, and the exposed surface of the sample faces the lamp. When the sample is not completely filled with the rack, the remaining empty space shall be filled with a blank plate to maintain the stability of the test conditions in the box. During the exposure period, the specimen positions in the center of the exposure area and at the edge of the exposure area shall be changed regularly to reduce uneven exposure

7.2 exposure test

start the test chamber, adjust the specified test conditions, and record the starting exposure time. The specified test conditions shall be kept constant throughout the exposure period

7.3 measurement of ultraviolet radiation

7.3.1 instrument measurement of radiation

regularly place the ultraviolet integrating illuminometer or radiometer beside the exposed sample rack to directly measure the ultraviolet radiation

7.3.2 determination of radiation with blue wool standard

see Appendix A for the method of determining radiation with blue wool standard

7.4 test specimen

take the specimen from the test chamber according to the specified exposure time or radiation amount for the determination of various properties

7.4.1 determination of mechanical properties

the mechanical properties shall be selected according to the use requirements. Generally, the change of tensile properties of samples shall be selected as the index. The inside of the sample measuring sensor is generally a resistance strain gauge. Before calibration, the environment shall be adjusted according to the provisions of GB 2941, and then the measurement shall be carried out according to the requirements of the corresponding test standards

7.4.2 evaluation of color change

evaluate the surface color change of the sample after aging according to the relevant standards of visual inspection or instrumental measurement

8 end of test

the result of sample exposure test can be expressed by the performance change rate when the sample is exposed to a certain time or a certain radiation amount (j/㎡), or the exposure time or radiation amount (j/㎡) required for the sample to change its performance to a specified value

the change rate of sample performance can be calculated according to formula ⑴

p= (A-0)/0 × 100

where: P - performance change rate ‰

0 - initial value of unexposed sample performance

a - measured value of sample performance after exposure

9 test report

test report includes the following contents:

a) requirements for test purpose

b) adopt the name and code of this standard

c) sample name, specification and quantity

d) model of test chamber and model of fluorescent ultraviolet lamp

e) UV exposure time and temperature, condensation exposure time and temperature

f) test time

g) test items and results

h) experimenter and others

appendix a

(Appendix to the standard)

application method of blue wool standard for measuring light radiation dose

a1 indicates that the

blue wool standard fabric sample (hereinafter referred to as "standard sample") is used to evaluate the color fastness of colored textiles to light and climate. Because the blue dye is sensitive to light radiation and has a certain quantitative relationship, it can be used to determine the radiation dose level, that is, the exposure period. The blue wool standard sample is divided into eight grades (i.e. eight grades), representing eight color fastness grades to light. Because the standard sample is easy to use and has a large number of data basis for its use, it can be used to determine the exposure period of rubber light resistance exposure test

note: refer to GB 730 for details

a2 procedure

a2.1 a group of blue wool standard samples numbered from 1 to 8 (grade) shall be placed adjacent to the sample for exposure test

a2.2 compare the color difference between the exposed blue wool standard sample and the unexposed blue wool standard sample, and compare it with the color difference grade of "gray sample card for color change assessment". When the color difference of No. 1 standard sample reaches level 4 of the color difference of the gray sample card, the radiation dose level (exposure level) is level 1/1, i.e. level 1/1 of the exposure period; When the color difference of No. 2 standard sample reaches the same level 4, the exposure period reaches level 2/1; And so on, until No. 8 standard sample shows 4 levels of color difference, i.e. 8/1 level of exposure period

a2.3 when the first batch of No. 8 standard sample reaches grade 8/1, replace the second batch of newly prepared No. 1 ~ No. 8 standard sample, and continue to put it into exposure. When the second batch of No. 8 standard sample shows that the color difference with the unexposed No. 8 standard sample is equal to grade 4 of the color difference of the gray card, the exposure period reaches grade 8/2

a2.4 discard the second batch of No. 8 standard samples and replace the third batch of newly prepared No. 1 ~ 8 standard samples to continue exposure. When the color difference of the third batch of No. 8 standard sample reaches level 4, the exposure period reaches level 8/3

a2.5 repeat this procedure as required to obtain 8/4, 8/5,..., 8/n grades, as listed in table A1

table A1 exposure period (grade)

grade

1/1

2/1

3/1

4/1

5/1

6/1

7/1

8/1

8/2

:

8/n each batch of No. 1 Blue standard sample reaches grade 4 of color difference of gray sample card

each batch of No. 2 Blue standard sample samples reach grade 4 of color difference of gray sample card

each batch of No. 3 Blue standard sample reaches grade 4 of color difference of gray sample card

each batch of No. 4 Blue standard sample reaches grade 4 of color difference of gray sample card

each batch of No. 5 Blue standard sample reaches gray Grade 4 color difference of color sample card

each batch of No. 6 Blue standard sample reaches grade 4 color difference of gray sample card

each batch of No. 7 blue standard sample reaches grade 4 color difference of gray sample card

each batch of No. 8 Blue standard sample reaches grade 4 color difference of gray sample card

each batch of No. 8 Blue standard sample reaches grade 4 color difference of gray sample card

note

1 8/exposure time of level 1 in the sunlight of temperate climate Dew is about 1 year

2 when there is no better method to replace the tangential pendulum force measuring mechanism, the continuous exposure method of No. 8 standard sample shall be used. (end)

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