AATCC 186-2018 “Weather Resistance: UV and Moisture Exposure”
This test method provides procedures for exposure testing of various textile materials, including coated fabrics and products made from them. The test was performed using a laboratory artificial aging exposure device with fluorescent UV tubes as light sources, using condensation humidification and/or spray humidification.

Principle: The sample is exposed to fluorescent UV light source and humidified regularly under controlled conditions. The material is assessed under standard textile testing conditions according to reference standards and exposure standards, and its degradation resistance is expressed as percentage loss of strength or percentage residual strength (breaking or bursting) or color change.

AATCC 186-2018 “Weather Resistance: UV and Moisture Exposure”

Sun fastness tester

Q-SUN B02-S for color fastness testing according to AATCC TM186

AATCC TM186 standard in detail
1. Purpose and scope
1.1 This test method provides exposure steps for a variety of textile materials, including coated fabrics and coated products, under laboratory artificial climate exposure equipment using fluorescent UV lamps as light sources, condensing humidity and/or water spray as wetting.

Step 2: The Rules
2.1 The sample shall be exposed to fluorescent ultraviolet light source under controlled conditions and be regularly wetted. When assessed under standard textile conditions, the degradation resistance of the tested material can be expressed as a percentage of strength loss or a percentage of residual strength (breaking or suitably bursting) and/or the colour fastness of the material.

3. Definition
3.1 Breaking strength, n. — The maximum force at which a specimen is pulled apart in a tensile test.

3.2 Bursting strength, n. – A force or pressure that acts at a suitable Angle on the fabric plane under specified conditions until the fabric bursts.

3.3 Fluorescent UV lamp, n – The radiation inside the lamp is converted at 254nm from a low-pressure mercury arc to a larger wavelength of UV through the phospor.

3.4 Irradiance, n – The amount of radioactive energy incident per unit area of the receiver, generally expressed in watt/square meter, W/m2.

3.5 Radiant energy, n. – Energy that travels through space in the form of photons or electromagnetic waves of different wavelengths.

3.6 Spectral energy distribution, n – the change in energy due to the wavelength span of a radioactive source.

3.7 Standard atmosphere for testing fabric, noun — maintain temperature 21±1℃, relative humidity 65%±2%.

3.8 Ultraviolet radiation, n. – The radiant energy of monochromatic light, with wavelengths smaller than those of visible radiation, but larger than 100nm. Note: The limits of the spectral range of UV radiation are not fully defined and may vary from user to user. CIE E-2.1.2 committee divides the spectral range between 400nm and 100nm: UV-A 315-400nm UV-B 280-315nm UV-R 280-400nm.

3.9 UVA fluorescent ultraviolet lamp, noun – The radiation emitted by a fluorescent ultraviolet lamp below 300nm is less than 2% of its total output light.

3.10 UVB-type fluorescent ultraviolet lamp, noun – A fluorescent ultraviolet lamp emits more than 10% of its total output of radiation below 300nm.

3.11 Climate, n – Weather conditions in a given geographic setting, including factors such as sunlight, rain, humidity, and temperature.

3.11 Weather resistance, noun – the resistance to degradation determined by the nature of the material itself when exposed to atmospheric conditions.

AATCC 186-2018 “Weather Resistance: UV and Moisture Exposure”

4. Safety measures
Note: This safety measure is for information reference only. This security measure is an adjunct to the test procedure and is not widely applicable. Users must handle the materials in this test method safely and properly. Consult the manufacturer for specific information, such as material safety data and other manufacturing recommendations. At the same time, it is necessary to comply with the standards and provisions of occupational safety and health regulations.

4.1 Observe good laboratory practices. Wear safety glasses in the laboratory area.

4.2 Operate the test instrument only after reading and understanding the manufacturer’s operating instructions. Persons operating the test instrument are required to follow the manufacturer’s operator safety guide.

4.3 Test equipment includes high brightness lamp. Don’t look directly at the light source. When the machine is running, it is necessary to close the door of the test instrument.

4.4 Before repairing the light source, make sure the operating light is cooled for 30 minutes after turning off.

4.5 When repairing the test equipment, turn off all switches on the front dial and the main power indicator switch. When assembling, make sure the main power indicator on the front dial of the machine is off.

AATCC 186-2018 “Weather Resistance: UV and Moisture Exposure”

5. Use and Limitation
5.1 The use of this procedure is used to model the degradation due to solar UV energy and water. Exposure is not intended to model degradation caused by localized climate phenomena, such as exposure to atmospheric pollution, biochemical attack, and saline water.

5.2 Warnings. Variations in operating conditions may result in variations in test results within the limits of acceptable conditions for this procedure. Therefore, do not refer to the results obtained using this test procedure unless specific operating conditions are indicated on the report.

5.3 The test results obtained in this procedure can be used to compare the relative durability of the materials used in a specific test period. Test results obtained from specimen exposure to different types of instruments cannot be compared unless a correlation has been established between the equipment used to test the material. Variations within the operating conditions of this procedure may result in different test results. Because of the diversity of results resulting from the use of this method and surface exposure, separate “acceleration factors” regarding hours of accelerated exposure to specific periods of outdoor exposure are not recommended. As the results may be diverse, do not refer to the results of the tests performed with the instruments used in this procedure unless specific requested information is indicated on the report.

5.4 A number of factors may reduce the correlation between accelerated tests performed using laboratory light sources and actual exposure.

5.4.1 Spectral distribution is different between laboratory light source and sunlight.

5.4.2 In laboratory accelerated exposure tests, exposures with shorter than normal wavelengths often fail more quickly. For outdoor exposure, short-wavelength UV radiation begins to be reduced at 300nm. Exposure to UV radiation with a wavelength of less than 300nm may produce degradation reactions, but the above reactions will not occur if the material is used outdoors. If the laboratory light source used in the accelerated test contains UV radiation with a wavelength shorter than that of the actual use conditions, the degradation machinery and stability rating of the material in the accelerated test will be completely different.

5.5 It is not necessary to simulate sunlight over the entire spectrum if it is known that radiation within a specified range can produce a type of degradation favorable to the test material without changing the stability level of the material. Laboratory light sources, relative to the ultraviolet afterlight and visible spectrum, have a strong amount of radiation in a narrow frequency band. However, it may be easier to produce very important special reactions relative to other light sources. This type of light source also does not change due to sunlight exposure. Exposure to light sources, which only produce UV radiation and do not produce discoloration caused by visible light radiation, may cause yellowing of polymers more significantly than exposure to sunlight.

AATCC 186-2018 “Weather Resistance: UV and Moisture Exposure”

6. Equipment (see 17.1)
6.1 Test Chamber (see 17.2)

6.2 UVA type fluorescent Ultraviolet Lamp (see 17.7)

6.3 Moisture System

6.3.1 Condensation. The moisture system is used to produce condensation or water spray, or both.

6.3.2 Water spray equipment. The laboratory shall be equipped with a device that can introduce intermittent water spray to the sample under specific conditions. The spray was spread unevenly over the sample. The spray system should be made of anticorrosive material and should not pollute the water used.

6.4 Black dial thermometer (see 17.8 and 17.9).

6.5 Sample clamp (see 17.10).

6.6 Location of test Chamber (see 17.11)

AATCC 186-2018 “Weather Resistance: UV and Moisture Exposure”

7. Test the sample
7.1 Number of samples. Use two samples, including the material under test and a standard for comparison to ensure accuracy. It is recommended that the aging test be repeated at least three times for each material to obtain statistical evaluation results. A large number of samples are used so that the results do not exceed about 5% of the true value at the 95% level. Determine the number of samples To determine a limit value and then use the variable coefficient, according to ASTM operation D2905, the number of samples required to determine the average mass of fabric.

7.2 Sample size. Some materials change in size when exposed. The manufacturer of test instruments, physical performance test equipment and the number of samples will affect the sample size. The test procedure used to evaluate the change in sample performance should be reviewed to ensure that the sample size is appropriate before proceeding to the next step. Cut the fabric into strips of dimensions not less than 102×152mm such that the longer sides are parallel to the warp or machine direction, unless otherwise stated, as follows:

7.2.1 Bursting strength (steel ball bursting).

7.2.2 Breaking strength (grasping stretch)

7.2.3 Color change.

7.2.4 In order to prevent fabric unwinding, the edges of the specimen shall be edged with flexible epoxy resin or similar material.

7.2.5 Label each specimen to identify the environmental resistance of the materials used in the test.

AATCC 186-2018 “Weather Resistance: UV and Moisture Exposure”

8. Test cycle measurement
8.1 The test cycle is better determined by the various influencing factors in use, especially the special climatic conditions. Each material is not necessarily affected the same way in the same environment. The results obtained from any one test cycle are not representative of any other test cycle or other outdoor tests. Factors originating in one location do not apply to any other location. However, certain test cycles can be applied to similar climates where the test is relevant.

8.2 The properties of the test material affect the selection of the test cycle, which relates to UV light, moisture, moisture time and temperature. The following test cycle options are used for fabric materials.

8.2.1 Option 1, general application: ultraviolet irradiation for 8 hours at 60℃, the irradiation is 0.77W/m2, and the bandwidth is 340nm; The condensation was followed by 4 hours at 50 ° C. This option is used for general applications such as outdoor furniture fabrics and tent fabrics.

8.2.2 Option 2, thermal vibration application: ultraviolet irradiation for 8 hours at 60℃, the irradiation is 0.77W/m2, and the bandwidth is 340nm; Followed by 0.25 hours of water spray; Condensation at 50 ° C for 3.75 hours; This option is used on buildings or in other applications where thermal vibrations are generated.

8.2.3 Option 3, automatic surface: UV irradiation for 8 hours at 70℃, the irradiation is 0.72W/m2, and the bandwidth is 340nm; Condensation at 50 ° C for 4 hours; Uv irradiance is monitored and maintained by either the manual method or the feedback loop method described in SAE J2020.

8.3 The use of these cycles does not imply an accelerated climate test, which is not limited to these cycles. The relevance of any actual outdoor climate exposure needs to be determined by quantitative analysis.

AATCC 186-2018 “Weather Resistance: UV and Moisture Exposure”

9. Criteria for comparison
9.1 The comparison standard can be any suitable fabric material, as long as its strength decay history and color change rate are known. The standard should be exposed to the test sample at the same time. The purpose of these standards is to demonstrate consistency between individual machines and test runs. If the test data of the exposed standard is more than 10% off the standard data, the operation is effectively checked and faults and defects are corrected. Let’s do the test again. If the error between the test data and the standard data is more than 10%, and there is no basis for machine failure, the test standard needs to be questioned and re-evaluated. Data obtained through questionable criteria should be wary and resolved by quantitative analysis.

10. Test procedures
10.1 Maintain and calibrate the instrument according to manufacturer’s recommendations.

10.2 Before the start of the exposure test, all specimens were placed under a moisture balanced fabric test atmosphere in accordance with ASTM D 1776 Standard Practice for Fabric Humidification and Testing. Water balance means that the sample is weighed frequently at intervals and the mass of the sample increases by no more than 0.1% of the sample mass in a period of no less than 2 hours. It is necessary to establish a reference line to compare unexposed samples with exposed samples when necessary tests and evaluations are performed.

10.3 Sample installation. Mount the specimen in the frame provided by the test cabinet, ensuring that the test surface is exposed to the light source. If the sample does not completely fill the sample holder, the remaining space needs to be filled with blank plates to maintain the test conditions inside the test chamber.

10.3.1 Attach a flexible specimen with toughness to a plate made of aluminum or other corrosion resistant heat conduction material.

AATCC 186-2018 “Weather Resistance: UV and Moisture Exposure”

10.3.2 Samples with holes and samples with openings greater than 1mm along irregular shapes shall be sealed to prevent the loss of water vapor. Porous specimens are blocked with aluminum or plastic water vapor blockers.

10.3.3 Fabric. The flexible fabric specimen is simply wound on an aluminum plate and secured with a coil clamp. The specimen presents a smooth surface in the test chamber (see Figure 1)(special installation of the flexible fabric specimen).

10.3.4 Yarn. Wrap the yarn around the frame with a minimum winding length of 150mm. Only the portion of yarn directly facing the radiated energy is used to measure breaking (stretching) strength. Conduct a single or multiple stock test. When doing the multi-strand test, the yarn is wrapped around the frame tightly packed to a width of 25.4mm. Blank samples should contain strings equal to the number of exposed subject samples. After exposure, before winding, bind the yarns facing the light source together, using 20mm plaster masking agent or other appropriate ribbon to keep the yarns tightly packed on the exposure frame for evaluation.

10.3.5 For woven, woven or non-woven fabrics, ensure that the usual surface of the test sample is directly exposed to a radiant light source.

10.4 Adjust the equipment to the required test conditions and continuously operate the test equipment within the limits specified above. Use test conditions specified in 8.2 or mutually agreed upon or in accordance with product quality specifications.

10.5 Continuously carry out the operation and repeat the cycle, except for equipment maintenance and sample inspection. Test the specimen daily during the middle of the condensation cycle to ensure uniform wetting of the specimen.

10.6 Minimize effects from changes in temperature or UV light. It is recommended that the sample be repositioned as shown in Figure 2(Sample rotation) by rotating the sample horizontally every week in the following two ways: (1) move the two rightmost handles of the sample gripper to the left of the exposed area. (2) Slide the retained sample gripper to the right.

AATCC 186-2018 “Weather Resistance: UV and Moisture Exposure”

11. Period of exposure
11.1 Use one of the following methods to assess the durability of exposure:

11.1.1 Specific amount of total time.

11.1.2 The number of exposure times required to produce a certain change in the test sample or approved standard sample.

12. Moisturize
12.1 If the test sample is wet when removed from the test stand, dry it under surrounding laboratory conditions or at a temperature not exceeding 71 ° C.

12.2 Then put the test samples in the atmospheric atmosphere under controlled conditions for humidification. All specimens were moved to water balance. Water balance means that the sample is weighed frequently at intervals and the mass of the sample increases by no more than 0.1% of the sample mass in a period of no less than 2 hours. As a general practice, the industry favors water balance from the “receiving party”.

12.3 Prepare the sample for each test and adjustment on the material, exposed or not exposed, by marking and cutting the middle part of each exposed specimen to the dimensions specified in the test procedure. Marking and cutting test samples is better done after exposure, but can also be prepared before exposure. Unexposed control specimens were similarly prepared and fully wetted and allowed to dry without tension prior to testing.

AATCC 186-2018 “Weather Resistance: UV and Moisture Exposure”

13. Evaluation results
13.1 Evaluate or calculate changes in exposed test samples according to applicable test methods in AATCC, ASTM or ISO.

13.2 Physical Properties.

13.2.1 Breaking strength of steel ball of fabric. To determine the strength of the steel ball breaking of fabrics according to the instructions in ASTM Test method D3787. Test method for the strength of the steel ball breaking of woven fabrics: constant transverse rate steel ball breaking test.

13.2.2 Tensile test by grasping sample method. According to ASTM D5034, the test method for tensile strength and elongation at break of fabrics is used to determine the tensile strength of the grasp (grasp method test).

13.3 Color change.

13.3.1 Grade of color change according to the light color fastness indicated in Method 16 of AATCC.

AATCC 186-2018 “Weather Resistance: UV and Moisture Exposure”

14. Report
14.1 Report the following information under exposure conditions:

14.1.1 Manufacturer and model of fluorescent UV/condensing equipment.

14.1.2 Designation of fluorescent UV lamp by manufacturer.

14.1.3 Exposure period, e.g.,4 hours UV /60 ° C,4 hours condensing /50 ° C. 14.1.4 Total exposure time.

14.1.5 Total UV light exposure time.

14.1.6 Degree of any deviation from the exposure test method.

14.2 Report the following information of the test specimen:

14.2.1 Report the material composition of the tested fabric, the exposure surface of the fabric (if the condition of each surface of the fabric is different), the quality of the fabric in grams per square meter and the properties of the fabric at termination.

14.3 The following information of the report on the assessment:

14.3.1 Report the level and relative data for each estimated performance.

14.3.2 Report the criteria used for comparative assessment.

14.3.3 Data. The AVERAGE value of different products was calculated, or statistically processed as appropriate, and the value of breaking or breaking strength and/or color fastness after exposure was recorded for comparison with the original strength and color. The report should contain a minimum value of: (a) method or mean (b) number of tests (c) standard deviation or coefficient of change without number of tests and accuracy of the method statement is invalid.

AATCC 186-2018 “Weather Resistance: UV and Moisture Exposure”

15. Accuracy and deviation
15.1 Accuracy

15.1.1 Laboratory studies. Back in 1991, a separate laboratory did a study to assess accuracy within the laboratory. A fabric (grayish brown, type #400 chintz) was exposed to the conditions of this test method, and the tensile strength of the grasp sample and the breaking strength of the steel ball after exposure were measured by △E*ab.

15.1.2 Internal laboratory accuracy. For each performance, the composition of variance indicated by the critical difference and the laboratory accuracy are given in Tables I, II, and III.

15.1.3 For each performance, the difference between test results should not exceed 95% of the value when the difference is solely due to selection. 15.1.4 Analysis of variance or t-test is used to compare means. See the standard data text for more information. 15.2 Deviation. 15.2.1 There is no method to determine the true value of weather resistance of textile materials. Acceptance bias with this test method cannot be determined, so this method has no known bias.