GB/T 31881-2015Accelerated weathering test methods of automotive nonmetal components and materials using a fluorescent UV and condensation apparatus (English PDF)

Foreword

This Standard is drafted in accordance with the rules in GB/T 1.1-2009.

1 Scope

This Standard specifies the test methods and evaluation methods to use UV aging test equipment to conduct accelerated aging against automotive non-metallic parts and materials.

This Standard applies to automotive plastics, rubber, coatings, adhesives, and other non-metallic parts and materials.

2 Normative references

The following documents are essential to the application of this document. For the dated documents, only the versions with the dates indicated are applicable to this document; for the undated documents, only the latest version (including all the amendments) are applicable to this document.

GB/T 250-2008 Textiles - Tests for color fastness - Grey scale for assessing change in color

GB/T 1766-2008 Paints and varnishes - Rating schemes of degradation of coats

GB/T 15596-2009 Plastics - Determination of changes in color and variations in properties after exposure to daylight under glass, natural weathering or laboratory light sources

GB/T 16422.3 Plastics - Methods of exposure to laboratory light sources - Part 3: Fluorescent UV lamps

3 Terms and definitions

The following terms and definitions apply to this document.

5 Test sample

5.1 The sample size shall be 50mm×75mm, 75mm×100mm, 75mm×150mm, 100mm×150mm, or as agreed between the test parties.

5.2 Before the test, the test sample shall be cleaned. AND it shall not use the cleaning agent which may erode sample surface. It is not allowed to wash away the intentionally applied protective film from the sample surface.

5.3 If the sample is cut from a large work piece, the test can be agreed by the test parties, BUT it shall ensure that the test part of the sample complies with the test requirements.

5.4 It shall take at least two samples, wherein one sample is used as file sample for evaluation and comparison, which is stored in a dark, dry environment.

Unless otherwise agreed by the test parties, the file sample is generally not covered by half.

5.5 To provide the aging record of different time intervals, it is needed to provide sufficient number of samples.

5.6 As for the insulating material sample, such as plastic or foam, it shall control the sample thickness, so as to ensure the heat transfer to make the sample surface form condensation.

5.7 As for soft sample, it shall fix it on an inert metal back plate.

5.8 In order to prevent the loss of water vapor during test, as for the samples which have 2mm-above holes OR 1mm-above gaps with sample holder due to shape inconsistency, it is needed to seal the hole and gap of sample. As for the porous samples, such as fabric, it shall use water vapor barrier materials, such as metal materials, as backing.

7 Test procedure

7.4 When the condensation cycle starts, BEGIN exposure test. In order to ensure the condensing effect during the condensation cycle, CHECK whether the sample surface is with condensation once a week.

7.5 In order to reduce the effects caused by the changes of temperature and UV irradiation, it shall periodically rotate the sample position. Horizontally move the sample at least once a week.

8 Test results and evaluation

When the test is finished, it shall evaluate the color change, gloss change, chalking, cracking, blistering, and peeling of the test sample.

As for the visual color change of the sample, refer to GB/T 250-2008. As for the gloss change of the sample, the instrument measured color change, chalking, cracking, blistering, rusting, peeling, mildew, etc., refer to GB/T 1766-2008 and GB/T 15596-2009.

9 Test report

The test report shall include the following.

a) Description of the test sample;

b) Indicated number of this Standard;

c) Selected test method (test method 1, test method 2);

d) Test results (given in Chapter 8);

e) Used UV aging equipment model and serial number;

f) Fluorescent UV lamp supplier name, lamp name specified by the manufacturer, lot number or date code, AND wavelength corresponding to irradiance peak;

g) UV irradiation cycle time and temperature, condensation cycle time and temperature;

h) Time of aging test;

i) Whether the test is conducted in stages;

j) Any differences from specified test methods;

Appendix A (Normative) Test equipment maintenance and calibration