Лако-красочные материалы — производство

General remarks

It is evident that a large number of parameters are involved in the fabrication and testing of bulk adhesive specimens and adhesive joints; these must be controlled if meaningful experimental data are to be obtained. Joint tests evaluate not only the mechanical properties of the adhesive, but also the degree of adhesion and the effectiveness of surface treatments. The standard test procedures listed by ASTM, BSI, DIN and other official bodies are essentially for testing adhesives and surface treatments rather than joints (e. g. Table 4.3). Unfortunately, most of these tests consist of joints in which the adhesive stresses are far from uniform. The designer and the researcher therefore have to select appropriate tests, and to know what the results mean in terms of their own particular investigations and applications.

Test procedures

Adhesive tests may be used for various reasons, including(25):

(1) comparing the mechanical properties of a group of adhesives

(2) as a quality check for a ‘batch’ of adhesive

(3) checking the effectiveness of surface and/or other preparations

(4) as a means of determining parameters that can be used in predicting performance in actual applications.

(l) -(3) may be classed as qualitative tests and a number of procedures may suffice. Quantitative results as required for reason(4) are much more demanding, requiring a detailed knowledge of the stress distribution within the test joint and its relationship to that in a real joint.