Лако-красочные материалы — производство

Best regarded as a combination theory, it postulates the chemical reactions between cou­pling agent, substrate, and polymer of the chemical bond theory together with the rigid interface of the restrained layer theory and the plastic interface of the deformable layer theory. It allows for stress relaxation by the reversible breaking of stressed bonds without loss of adhesion in the presence of water. It also argues that when Si-O or Ti-O substrate bonds are broken by the intrusion of water, they may re-form with some recovery in adhesion. It is likely that hydrogen bonding is a particularly important aspect of this theory, especially in the case of silanes [18]. Recovery of adhesion between urethane and epoxide coatings and metal substrates on drying out after water immersion has been demonstrated by Walker [19-21]. It is now generally accepted that some silane coupling agents do not need to react with the polymer chemically to provide enhanced initial and wet adhesion [16,22].