Adhesion durability reversibility

Labels produced in this manner are applied according to the following procedure. The adhesive coat is heated directly by infrared radiation or hot air, or by hot plates from the reverse side, to a temperature above the melting point of the plasticizer. The polymer is plasticized (i.e., the coating is tackified by the molten plasticizer, which is present in excess). Under this condition, the label can be bonded to the substrate by applying a slight pressure. Adhesion to glass, metals, polyvinyl chloride (PVC), wood, etc., is durable even after the plasticizer has recrystallized. 

It should be noted that although no distinction is made between the endo and exo stereoisomers (Fig. 12.25) of furan-maleimide adduct (assuming that their thermal behavior is at least similar if not equal), differences in thermal reversibility (rDA, DA) can have an important in uence on the material properties, especially in the case of thermoremendable polymers and networks. For instance, by breaking only the covalent bonds of the endo DA-isomers inside the network imder mild conditions and reforming them in a less stressed state, stresses can be relaxed. Important material properties such as durability, adhesion to other materials, appearance of micro-voids and micro-cracks, etc., can be improved (Canadell et al., 2010). 

Reversibility of a joint requires that the adhesion failure should be complete, but only when required. If a polymer is chemically bound to an object it is most unlikely that it will be removed withont cansing physical damage to the surface. A bond that is durable to weathering is probably irreversible. 

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