Лако-красочные материалы — производство

The test methods presently used to evaluate the adhesion of pressure-sensitive adhesives to release liners are modified adhesion tests, such as the 180° or 90° peel test, with the liner adhered to a test panel, or a T-peel test, where the sample is freely suspended while the tape is peeled at a controlled rate from the release liner. The values obtained by the latter method are affected considerably by the stiffness of the liner, which alters the angle of peel.

One method occasionally used evaluate the relationship of silicone release liners or other materials of very low surface energy to a pressure sensitive, is to bring a coated pressure sensitive into contact with the liner under pressure, to carry out an adhesion test. This is of little value, as the adhesive is unable to wet out and so come into intimate contact with the release liner. The adhesive must first be coated onto the liner, dried, or cooled in the case of a hot melt, and then a carrier laminated to it, as is standard practice for transfer coating. As low values of adhesion can be expected, the force required to bend the backing may dominate, and so a thin flexible backing should be used, to maintain a constant peel angle, 25 pm polyester being satisfactory. Then a standard 180° peel test can be carried out with the release liner secured to a test panel.