ASTM D904:99(R2021) pdf free download – Standard Practice for Exposure of Adhesive Specimens to Artificial Light.
4.2 This practice is not for determining a forecast of the life of an adhesive bond in service. It is only for determining the relative durability of different adhesives compared to each other.
4.3 The results obtained may vary between the different light sources (xenon-arc or fluorescent UV). because of the different specual-irradianee of the lamps. Adhesives should not be compared to each other based on their performance under different types of light sources.
4.4 The results obtained may vary when operation conditions are varied within the limits of a given method. The results may also vary when exposures arc performed on instruments made by different manufacturers. Comparisons between materials must only be made when they are tested at the same time in the same instrument. Be sure to accurately report the operating conditions.
4.5 The type and UV transmittance characteristics of the transparent adherend used can have a significant effect on the rate and type of degradation of the adhesives being tested. Comparisons between adhesives must only be made when tested on transparent adherends of the same type (preferably the same lot) with the same UV transmission.
4.6 This practice is not for determining the effects of atmospheric pollutants, biological organisms, salt, or freeze/ thaw cycles.
5. Method A—Fluorescent UV
5.2 Lump 1\pe—Usc fluorescent UV-A lamps. with a peak emission at 343 nm.
Note I—UV.A lamps are preferable to Uw’-B lamps. because UV-A wasclengths can pass through the transparent puilion of the test specimen withoum being absothed. whereas flks’ of the UV-B waselengths are tilicrcd out by the glass.
5.2.1 Other fluorescent UV lamps meeting the size and electrical characteristics in 5.2 may be used by prior agreement. provided that the lamp and spectral power distribution are reported in conformance with Section 7. Use of lamps other than those specified in 5.2 may result in significant differences in test results.
5.3 Specimen Mounting—Mount the specimens in the specimen holders so that the LIV passes through the transparent adherend to reach the adhesive joint or so that the joint is exposed to the effects of condensation (if applicablet. Use a suitable hacking panel to ensure that vapor does not escape from the test chamber around the test specimen. When the lest specimens do not completely till the racks, till the empty spaces with blank panels to maintain the test conditions within the chamber.
5.4 Time /Tenperaure Cvck.s—Program the apparatus to achieve the desired test conditions, as follows:
5.4.1 cycle 1—4 h UV at 60 ± 3C followed by 4 h condensation at 50 ± 3SC, for applications where the adhesive will be exposed to moisture.