Significance and Use
This test method is useful to the adhesive manufacturer in research and development or in manufacturing control. The results are also used for specification acceptance or as a guide in adhesive selection.
The provisions for testing bonded specimens as well as free films are made for two purposes. First, it is possible for an interaction to occur between oxygen and chemicals or degradation products that may affect the degradation of the bonded joints strength. Second, some increase in strength due to oxidative crosslinking may not be detrimental in a bonded assembly and in fact may be beneficial. Adhesives of this behavior are not satisfactorily tested by a film flexibility test.
Some users of this test method will be most interested in the performance of the bonded joint; some will be most interested in the performance of the adhesive. In the latter case, it is important to note that the true variance (error mean square) of the strength of the adhesive may be obscured when the tested control specimens or the tested aged specimens show wood failure.
Conflict of Procedure—If the procedures of this test method conflict with those of detailed product specifications or manufacturer's use instructions for a particular material, then use the latter.
1.1 This test method describes how to estimate the relative resistance to deterioration of adhesive films and adhesive-bonded joints placed in a high-pressure oxygen environment. The instructions include both wood-to-wood and wood-to-metal joints as well as free film of adhesive. The effects of chemicals such as fire retardants, preservatives, or wood extractives, can be evaluated by using materials containing these chemicals for adherends.
1.2 This test method is primarily intended for elastomer-based construction adhesives, but is also applicable to other types of adhesives that may be susceptible to oxygen degradation. This accelerated test does not correlate exactly with the natural aging of the adhesive because of the varied conditions of natural aging and the absence of factors such as moisture and stress. The results of this accelerated test are only comparative and must be evaluated against the performance of bonded joints whose natural and accelerated aging characteristics are known.
1.3 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use.