Incoming material control adhesives

As with the quality control plan for the formulator described above, acceptance tests on adhesives should be directed toward assurance that incoming materials are identical from lot to lot. However, this plan should also extend to the receipt and control of incoming adherends and other materials used in the bonding process. 

In addition to tests performed on the incoming materials, test specimens may be made to verify the strength of the adhesive joint. The quality control tests should be those that can quickly and accurately detect deficiencies in the adhesive s physical or chemical properties. ASTM lists various test methods that are commonly used for adhesive acceptance. 

Incoming adhesive material control includes two types of tests, physical properties, such as percent flow, gel time, and percent volatiles, which are... 

The second step, after determining the quality of incoming materials, is adherend surface preparation. Surface preparation must be carefully controlled for reliable production of adhesive-bonded parts. 

DSC is thus a quick and reliable method of analysis, not only in material development, but primarily in the areas of quality assurance, raw material control and failure analysis. DSC is used for identification of incoming plastic materials e.g. HDPE/PA6 and LDPE/EVAL/PA6 composite film. DSC can not only identify the major components of polymers, but can also detect minor components such as adhesives, if these have a melting behaviour which differs from that of the polymers. Quality control of packaging film without sample preparation is based on the measurement of the solid/liquid phase transition of melting by means of DSC. Sass [175] has given various examples of quality assurance and defect analysis of plastics by DSC. There is increased demand for sensitivity and capability because of the growing complexity of materials. 

Incoming adhesive material control includes two types of tests, physical properties, such as percent flow, gel time, and percent volatiles, which are of interest to the process engineer in assuring the quality of the bond. An example is the test for percent flow. This test is of value in maintaining the bonding process so that the adhesive flow is not be too high, which could cause an adhesive-starved bond. Too little flow, on the other hand, would cause a thick or inadequately filled bond [6]. Test methods used for physical properties include the following ... 

The second step, after determining the quality of incoming materials, is adherend surface preparation [7]. Surface preparation must be carefully controlled for reliable production of adhesive-bonded parts. If a chemical surface treatment in required, the process must be monitored for proper sequence, bath temperature, solution concentration, and contaminants. If sand- or gritblasting is employed, the abrasive must be changed regularly. 

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