Evaluating EVA/glass adhesion is a good test to determine if the encapsulant material has been overexposed to moisture during storage or shipping as well as its fitness for use. A 180° peel test can be utilized to measure encapsulant adhesive strength to glass. This simple test involves laminating EVA coupled to a backsheet such as TPE or TPT to glass. The backsheet serves as a pulling substrate during the test.

STR considers EVA glass strength 53 N/10 mm (30 lb/in) or greater satisfactory. Typical glass adhesion values are between 70 and 86 N/10 mm (40-50 lb/in).

STR’s procedure for measuring EVA/glass adhesion can be downloaded here.