GB/T 14835-1993 Test method for resistance of vulcanized rubber to sunlight exposure under glass
Some standard content:
National Standard of the People's Republic of China
Rubber ,vulcanized-Test method of exposurefor resistance daylight under glassGB/T14835--93
This standard adopts the international standard ISO4665/2-1985 "Vulcanized rubber-Weather resistance-Part 2: Method of exposure to weathering".
1 Subject content and scope of application
This standard specifies the test method for the resistance of vulcanized rubber to sunlight aging when exposed to outdoor glass. This standard is applicable to the evaluation of the sunlight aging resistance of vulcanized rubber. 2 Reference standards
GB250 Grey scale for evaluating discoloration
GB/T528 Determination of tensile properties of vulcanized rubber and thermoplastic rubber GB730 Blue wool standard for color fastness to light and weather GB2941 Standard temperature, humidity and time for environmental conditioning and testing of rubber specimens GB/T3511 Test method for atmospheric aging of rubber GB9865 Preparation of vulcanized rubber samples and test specimens 3 Principle
Sunlight (especially ultraviolet light) is one of the main factors causing rubber aging. Placing vulcanized rubber under a transparent glass cover outdoors can avoid the direct effects of factors such as wind and rain, and only being exposed to sunlight through the glass can still cause aging of the vulcanized rubber. The changes in performance of the specimens after being exposed to sunlight under the glass and the solar radiation dose received are tested to evaluate the sunlight aging resistance of the vulcanized rubber. 4 Device
4.1 Exposure rack
The exposure rack is a bracket used to mount the specimen for exposure test. It is mainly divided into two parts: the upper part is a specimen rack with a glass top and a fabric screen; the lower part is a supporting tripod. Its structure is similar to the exposure rack recommended in GB/T3511, except for the top cover and the screen. It can be made of anti-corrosion metal or wood. Figure 1 is a recommended exposure rack. Figure 2 is a recommended specimen rack. Approved by the State Administration of Technical Supervision on December 30, 1993, and implemented on October 1, 1994
865×560
GB/T14835-93
Figure 1 Recommended exposure rack
1-Corrugated glass plate; 2-Top cover, 3-Sample rack; 4-Ventilation hole; 5-Screen; 6-Bracket
GB/T14835-93
Figure 2 Recommended sample rack
4.1.1 Top cover
The top cover of the exposure rack is made of colorless and transparent flat glass with a thickness of 2-3mm and a frame around it. The glass should be flat and smooth, without bubbles, impurities and other defects, with uniform transparency, and the transmittance in the range of 370-380nm and the entire visible light wavelength should be close to 90%, and the transmittance in the range of 300-310nm and shorter wavelengths should be less than 1%. In order to ensure the light transmittance of the glass, the glass should be replaced after two years of exposure. The top cover is about 75mm away from the sample frame to ensure that the sample has appropriate space for ventilation. The unobstructed surface of the glass should be larger than the sample frame to avoid shadows.
The top cover should be evenly and tightly covered on the sample frame to prevent the sample from being directly attacked by wind and rain. Note: When the exposed sample is very thick, the distance between the glass plate and the sample should be appropriately increased, and the sample should not be in contact with the glass. 4.1.2 Sample frame
The sample frame is a frame for placing the sample, made of inert materials that are harmless to the sample. The structure should be suitable for installing the sample and ensure that there is enough space for ventilation. Its lower end should not be less than 0.5m from the ground. All parts that come into contact with the sample must be made of inert materials that are harmless to the sample183
(such as wood, aluminum alloy or stainless steel, etc.). 4.1.3 Screen
GB/T14835-93
The screen is a mesh fabric supported under the sample holder. The mesh has an aperture of about 1.6 mm and is made of corrosion-resistant inert materials that are harmless to the test, such as metal or other fabrics.
4.2 Instruments or standard substances for determining the exposure period Depending on the conditions and needs, any instrument or standard substance can be selected to determine the exposure period of the test. 4.2.1 Light receiving instrument
There are many types of light receiving instruments, such as pyranometers, illuminometers, etc. The instruments used should be accurate, sensitive and stable, and should be calibrated at least once a year
4.2.2 Blue wool standard and gray standard sample card The blue wool standard should comply with the relevant provisions of GB730. The determination method can be found in Appendix A. The gray standard sample card is used to evaluate discoloration and should comply with the relevant provisions of GB250.
4.3 Meteorological observation instruments
According to conditions and needs, meteorological observation instruments such as temperature and humidity can be set up in the test site to record meteorological elements such as the temperature and relative turbidity of the test environment. Www.bzxZ.net
5 Samples
5.1 The preparation of the samples shall comply with the relevant provisions of GB9865. 5.2 The shape and specifications of the samples shall be selected according to the evaluation indicators and the requirements of the corresponding test standards. For example, for the samples to evaluate the change of tensile properties, dumbbell-shaped samples specified in GB/T528 can be used. For the samples to measure the changes in appearance such as color and gloss, samples with a length and width of not less than 10cm can be used.
5.3 The number of samples shall be determined according to the test items, exposure cycles and requirements of the corresponding standards. The number of valid samples for each test is generally not less than 3.
6 Test conditions
6.1 Requirements for exposure sites
6.1.1 According to the test purpose and requirements, combined with my country's climate type and actual use conditions, select a suitable exposure site. The main climate types in my country can be found in Appendix A of GB/T3511. 6.1.2 The requirements of the standard exposure field shall comply with the provisions of Article 3.2 of GB/T3511, and other requirements shall refer to the relevant provisions of Articles 3.3 and 3.4 of GB/T3511.
6.2 The orientation of the exposure rack
6.2.1 The exposure rack shall be fixed in the exposure field and be able to withstand the maximum local wind force. The exposure surface of the specimen on the rack shall face due south. Generally, an exposure angle of 45° to the horizontal plane is adopted. Other exposure angles can also be adopted as needed. For example, if the specimen is to obtain the maximum annual radiation, an exposure angle equal to the local geographical latitude can be selected. However, tests using non-45° exposure angles must be stated in the test report.
6.2.2 The positions between the exposure racks should avoid mutual shading and be convenient for work. The distance between the south exposure rack and the surrounding obstacles, and the highest point of the east, south and west obstacles, should not exceed the 20° elevation angle formed by the lower end of the rack and the horizontal plane; at the highest point of the north obstacle, it should not exceed the 45° elevation angle formed by the upper end of the rack and the horizontal plane. 6.3 State of the specimen
The specimen is generally in a free state during the exposure test, and it can also be placed in a deformed state under stress as needed. 7 Test time and exposure period
The exposure test time is best selected in the season with strong sunlight, and the test time is best in summer. GB/T 14835-93
The exposure period should generally be determined according to the use requirements and the degree of change of the specimen. The exposure period can be calculated by exposure time (days, months, years) or radiation dose (J/m2).
The methods for determining radiation dose include the blue wool standard method and the instrument method. 7.1 Selection of exposure time
Unless otherwise specified, the exposure period can be selected from the following time series. Days: 1; 2: 3: 7; 7Xn.
Months. 1; 2; 3; 6, 9; 12; ·.
Years. 11. 5; 2; 3; 4; 6, ….
7.2 Blue wool standard to determine the exposure period
A set of blue wool standard fabrics numbered 1 to 8 (grades) in long strips are exposed together with the test sample. The color difference level of the "grey sample card for color change assessment" is used as the reference to compare the color difference between the exposed and unexposed blue wool standard fabrics, thereby determining the exposure period of the test sample.
For specific measurement methods, see Appendix A.
7.3 Instrumental method to determine exposure period
Place light receiving instruments, such as pyranometers, illuminometers, etc., under the glass cover of the exposure rack to directly measure the total solar radiation dose received, or measure the ultraviolet radiation dose and radiation dose of other wavelengths separately, and then refer to the radiation dose required for use to determine the exposure period of the sample.
8 Test steps
8.1 Install the sample
8.1.1 The prepared sample shall first be environmentally conditioned according to the provisions of GB2941, then the initial performance shall be tested, and then fixed on the exposure rack in the exposure field according to the test requirements.
8.1.2 The position of the sample in the rack shall not be blocked by shadows during the entire exposure period. The rolling direction of the sample shall be arranged in a north-south direction, and the spacing between them shall not be less than 5mm.
8.2. Placement of blue standard fabric or other physical standard instrument The blue standard fabric or other physical standard instrument shall be placed in accordance with the method described in 7.2 and 7.3, adjacent to the sample and on the same plane as the sample.
8.3 Covering the glass cover
The glass cover shall be tightly covered on the sample holder to ensure that rainwater does not penetrate into the cover. During the exposure period, the glass surface shall be frequently scrubbed to keep it clean. 8.4 Testing the sample
The exposure time shall be calculated after the sample is exposed, and the sample shall be tested according to the predetermined exposure period and the selected performance standard requirements. 8.4.1 Testing the appearance changes
The items for testing the appearance of the sample include: color, gloss, cracks, precipitates, stickiness, hardening and other changes. It is recommended to use color, cracks and precipitates as the main indicators. The test can be carried out by visual inspection or instrumental measurement. The visual inspection method can refer to the method in Appendix B of GB/T3511. The instrumental measurement method shall be carried out in accordance with the relevant standard requirements. 8.4.2 Determination of mechanical and other properties
Mechanical properties should be selected according to the use requirements. The tensile properties and hardness changes of the sample can be selected as indicators. Before the measurement, the environment should be adjusted according to the conditions specified in GB2941, and then the performance measurement should be carried out according to the requirements of the corresponding standards. 8.4.3 After the performance test of the sample is completed, if the test needs to be continued, the sample should be returned to its original state for exposure until the test is completed. 9 Test results
The exposure test results can be expressed by the performance value or change rate of the sample after aging. It can also be expressed by the exposure period when the sample performance changes to a certain time.
GB/T 14835-93
The change rate of the sample aging performance can be calculated by the following formula: p = a
2 × 100
Where: P -- the change rate of performance, %;
. -- the initial value of the performance of the unexposed sample; the measured value of the performance of the sample after exposure.
The exposure period can be expressed by the actual number of days, months or years of exposure, the exposure level of the blue wool standard or the radiation dose (J/m\). 10 Test report
The test report includes the following contents:
Test purpose and requirements;
The code and name of this standard cited;
Detailed information of the sample (including name, source, specification, quantity and preparation method, etc.); climate type and meteorological elements of the test site (including temperature, humidity and solar radiation, etc.); exposure test conditions (including ground conditions of the exposure site, sample status, exposure azimuth angle and light transmittance of glass, etc.); test time and exposure period;
Detection indicators and methods;
Test results and others.
A1 Description
GB/T 14835—93
Appendix A
Method for using blue wool standard to measure light radiation dose (supplement)
Blue wool standard fabric samples (referred to as "standard samples") are used to assess the light and weather fastness grades of colored textiles. Since the blue dye is sensitive to light radiation and has a certain quantitative relationship, it can be used to determine the radiation dose grade, i.e., the exposure period. The blue wool standard samples are divided into eight grades (i.e., 8 numbers), representing 8 light fastness grades. Since the standard samples are easy to use and there is a lot of data to support their use, they can be used to determine the exposure period of the rubber light exposure test. Note: For details, refer to GB730.
A2 Procedure
A2.1 A set of blue wool samples numbered from 1 to 8 (grades) are placed on the surface of the blue wool standard samples. The colored wool standard is placed adjacent to the test specimen and the exposure test is carried out at the same time. A2.2 Compare the color difference between the exposed blue wool standard and the unexposed blue wool standard, and compare it with the color difference level of the "Gray Sample Scale for Assessing Discoloration". When the color difference of standard No. 1 reaches the color difference level 4 of the gray sample scale, the radiation dose level (exposure level) is 1/1, which means it reaches the exposure period level 1/1; when the color difference of standard No. 2 reaches the same color difference level 4, it reaches the exposure period level 2/1; and so on, until standard No. 8 shows a color difference level 4, which means it reaches the exposure period level 8/1. A2.3 When the first batch of No. 8 standard samples reaches level 8/1, replace them with the second batch of newly prepared No. 1 to 8 standard samples, and continue to expose them until the second batch of No. 8 standard samples show the same color difference as the unexposed ones. When the color difference of the exposed No. 8 standard sample is equal to the color difference of the gray card at level 4, the exposure period reaches level 8/2. A2.4 Discard the second batch of No. 8 standard samples and replace them with the third batch of newly prepared No. 1 to No. 8 standard samples for continued exposure. When the third batch of No. 8 standard samples reaches a color difference of level 4, the exposure period reaches level 8/3.
A2.5 Repeat this procedure as needed to obtain levels 8/4, 8/5, .., 8/n, as listed in Table A1. Table A1 Exposure period (level)
Color difference description
The first batch of No. 1 blue standard sample reached a color difference of 4 levels on the gray cardThe first batch of No. 2 blue standard sample reached a color difference of 4 levels on the gray cardThe first batch of No. 3 blue standard sample reached a color difference of 4 levels on the gray cardThe first batch of No. 4 blue standard sample reached a color difference of 4 levels on the gray cardThe first batch of No. 5 blue standard sample The first batch of No. 6 blue standard sample reached the gray scale color difference of 4 levels. The first batch of No. 7 blue standard sample reached the gray scale color difference of 4 levels. The first batch of No. 8 blue standard sample reached the gray scale color difference of 4 levels. The second batch of No. 8 blue standard sample reached the gray scale color difference of 4 levels. The nth batch of No. 8 blue standard sample reached the gray scale color difference of 4 levels. Note: ① The exposure time to reach the sudden exposure period of 8/1 level is about 1 year in the sunlight of the temperate climate. ② When there is no better method to replace, only the continuous exposure method of No. 8 standard sample should be used. 187
Additional remarks:
GB/T14835--93
This standard was proposed by the Ministry of Chemical Industry of the People's Republic of China. This standard is under the jurisdiction of the Rubber Industry Research and Design Institute of the Ministry of Chemical Industry. This standard was drafted by the Institute of Synthetic Materials Aging of the Ministry of Chemical Industry. The main drafters of this standard are Chen Jingsheng and Feng Yuyi. 488%;
. —Initial value of the performance of the unexposed sample; measured value of the performance of the sample after exposure.
The exposure period can be expressed by the actual number of days, months, years of exposure, the exposure level of the blue wool standard or the radiation dose (J/m\). 10 Test report
The test report includes the following contents:
Test purpose and requirements;
The code and name of this standard cited;
Detailed information of the sample (including name, source, specification, quantity and preparation method, etc.); climate type and meteorological elements of the test site (including temperature, humidity and solar radiation, etc.); exposure test conditions (including exposure site ground conditions, sample status, exposure azimuth angle and glass transmittance, etc.); test time and exposure period;
Detection indicators and methods;
Test results and others.
A1 Description
GB/T 14835—93
Appendix A
Method for using blue wool standard to measure light radiation dose (supplement)
Blue wool standard fabric samples (referred to as "standard samples") are used to assess the light and weather fastness grades of colored textiles. Since the blue dye is sensitive to light radiation and has a certain quantitative relationship, it can be used to determine the radiation dose grade, i.e., the exposure period. The blue wool standard samples are divided into eight grades (i.e., 8 numbers), representing 8 light fastness grades. Since the standard samples are easy to use and there is a lot of data to support their use, they can be used to determine the exposure period of the rubber light exposure test. Note: For details, refer to GB730.
A2 Procedure
A2.1 A set of blue wool samples numbered from 1 to 8 (grades) are placed on the surface of the blue wool standard samples. The colored wool standard is placed adjacent to the test specimen and the exposure test is carried out at the same time. A2.2 Compare the color difference between the exposed blue wool standard and the unexposed blue wool standard, and compare it with the color difference level of the "Gray Sample Scale for Assessing Discoloration". When the color difference of standard No. 1 reaches the color difference level 4 of the gray sample scale, the radiation dose level (exposure level) is 1/1, which means it reaches the exposure period level 1/1; when the color difference of standard No. 2 reaches the same color difference level 4, it reaches the exposure period level 2/1; and so on, until standard No. 8 shows a color difference level 4, which means it reaches the exposure period level 8/1. A2.3 When the first batch of No. 8 standard samples reaches level 8/1, replace them with the second batch of newly prepared No. 1 to 8 standard samples, and continue to expose them until the second batch of No. 8 standard samples show the same color difference as the unexposed ones. When the color difference of the exposed No. 8 standard sample is equal to the color difference of the gray card at level 4, the exposure period reaches level 8/2. A2.4 Discard the second batch of No. 8 standard samples and replace them with the third batch of newly prepared No. 1 to No. 8 standard samples for continued exposure. When the third batch of No. 8 standard samples reaches a color difference of level 4, the exposure period reaches level 8/3.
A2.5 Repeat this procedure as needed to obtain levels 8/4, 8/5, .., 8/n, as listed in Table A1. Table A1 Exposure period (level)
Color difference description
The first batch of No. 1 blue standard sample reached a color difference of 4 levels on the gray cardThe first batch of No. 2 blue standard sample reached a color difference of 4 levels on the gray cardThe first batch of No. 3 blue standard sample reached a color difference of 4 levels on the gray cardThe first batch of No. 4 blue standard sample reached a color difference of 4 levels on the gray cardThe first batch of No. 5 blue standard sample The first batch of No. 6 blue standard sample reached the gray scale color difference of 4 levels. The first batch of No. 7 blue standard sample reached the gray scale color difference of 4 levels. The first batch of No. 8 blue standard sample reached the gray scale color difference of 4 levels. The second batch of No. 8 blue standard sample reached the gray scale color difference of 4 levels. The nth batch of No. 8 blue standard sample reached the gray scale color difference of 4 levels. Note: ① The exposure time to reach the sudden exposure period of 8/1 level is about 1 year in the sunlight of the temperate climate. ② When there is no better method to replace, only the continuous exposure method of No. 8 standard sample should be used. 187
Additional remarks:
GB/T14835--93
This standard was proposed by the Ministry of Chemical Industry of the People's Republic of China. This standard is under the jurisdiction of the Rubber Industry Research and Design Institute of the Ministry of Chemical Industry. This standard was drafted by the Institute of Synthetic Materials Aging of the Ministry of Chemical Industry. The main drafters of this standard are Chen Jingsheng and Feng Yuyi. 488%;
. —Initial value of the performance of the unexposed sample; measured value of the performance of the sample after exposure.
The exposure period can be expressed by the actual number of days, months, years of exposure, the exposure level of the blue wool standard or the radiation dose (J/m\). 10 Test report
The test report includes the following contents:
Test purpose and requirements;
The code and name of this standard cited;
Detailed information of the sample (including name, source, specification, quantity and preparation method, etc.); climate type and meteorological elements of the test site (including temperature, humidity and solar radiation, etc.); exposure test conditions (including exposure site ground conditions, sample status, exposure azimuth angle and glass transmittance, etc.); test time and exposure period;
Detection indicators and methods;
Test results and others.
A1 Description
GB/T 14835—93
Appendix A
Method for using blue wool standard to measure light radiation dose (supplement)
Blue wool standard fabric samples (referred to as "standard samples") are used to assess the light and weather fastness grades of colored textiles. Since the blue dye is sensitive to light radiation and has a certain quantitative relationship, it can be used to determine the radiation dose grade, i.e., the exposure period. The blue wool standard samples are divided into eight grades (i.e., 8 numbers), representing 8 light fastness grades. Since the standard samples are easy to use and there is a lot of data to support their use, they can be used to determine the exposure period of the rubber light exposure test. Note: For details, refer to GB730.
A2 Procedure
A2.1 A set of blue wool samples numbered from 1 to 8 (grades) are placed on the surface of the blue wool standard samples. The colored wool standard is placed adjacent to the test specimen and the exposure test is carried out at the same time. A2.2 Compare the color difference between the exposed blue wool standard and the unexposed blue wool standard, and compare it with the color difference level of the "Gray Sample Scale for Assessing Discoloration". When the color difference of standard No. 1 reaches the color difference level 4 of the gray sample scale, the radiation dose level (exposure level) is 1/1, which means it reaches the exposure period level 1/1; when the color difference of standard No. 2 reaches the same color difference level 4, it reaches the exposure period level 2/1; and so on, until standard No. 8 shows a color difference level 4, which means it reaches the exposure period level 8/1. A2.3 When the first batch of No. 8 standard samples reaches level 8/1, replace them with the second batch of newly prepared No. 1 to 8 standard samples, and continue to expose them until the second batch of No. 8 standard samples show the same color difference as the unexposed ones. When the color difference of the exposed No. 8 standard sample is equal to the color difference of the gray card at level 4, the exposure period reaches level 8/2. A2.4 Discard the second batch of No. 8 standard samples and replace them with the third batch of newly prepared No. 1 to No. 8 standard samples for continued exposure. When the third batch of No. 8 standard samples reaches a color difference of level 4, the exposure period reaches level 8/3.
A2.5 Repeat this procedure as needed to obtain levels 8/4, 8/5, .., 8/n, as listed in Table A1. Table A1 Exposure period (level)
Color difference description
The first batch of No. 1 blue standard sample reached a color difference of 4 levels on the gray cardThe first batch of No. 2 blue standard sample reached a color difference of 4 levels on the gray cardThe first batch of No. 3 blue standard sample reached a color difference of 4 levels on the gray cardThe first batch of No. 4 blue standard sample reached a color difference of 4 levels on the gray cardThe first batch of No. 5 blue standard sample The first batch of No. 6 blue standard sample reached the gray scale color difference of 4 levels. The first batch of No. 7 blue standard sample reached the gray scale color difference of 4 levels. The first batch of No. 8 blue standard sample reached the gray scale color difference of 4 levels. The second batch of No. 8 blue standard sample reached the gray scale color difference of 4 levels. The nth batch of No. 8 blue standard sample reached the gray scale color difference of 4 levels. Note: ① The exposure time to reach the sudden exposure period of 8/1 level is about 1 year in the sunlight of the temperate climate. ② When there is no better method to replace, only the continuous exposure method of No. 8 standard sample should be used. 187
Additional remarks:
GB/T14835--93
This standard was proposed by the Ministry of Chemical Industry of the People's Republic of China. This standard is under the jurisdiction of the Rubber Industry Research and Design Institute of the Ministry of Chemical Industry. This standard was drafted by the Institute of Synthetic Materials Aging of the Ministry of Chemical Industry. The main drafters of this standard are Chen Jingsheng and Feng Yuyi. 488
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