Crosslinking of acrylate copolymers in pressure sensitive adhesives

In order to make the acrylic ester pressure-sensitive adhesive have better adhesion, must make the copolymer have a higher weight average relative molecular weight, however, such adhesives, especially solution pressure sensitive adhesive, often in viscosity too large and difficult to coat. Without too much, if the relative molecular mass and viscosity are not too much of a copolymer in the coating or coating after proper crosslinking, and can solve the contradiction of performance and worker Kou. At the same time, crosslinking can improve the high-temperature resistance, solvent resistance, and aging resistance of pressure-sensitive adhesives, so the crosslinking of acrylate copolymer has very important practical value.

Specific cross-linking methods can be summarized as follows:

(1) The use of active hydroxymethyl condensation reaction and crosslinking, and N- hydroxymethyl acrylamide copolymerization and acrylic copolymer, alone or acid catalyst heating, can be due to active N- hydroxymethyl mutual condensation self-crosslinking, known as self-crosslinking, can also be added crosslinking agent, known as a diplomatic link. Hydroxyl or carboxyl acrylate copolymer and active hydroxyl methyl crosslinking agent, heating or acid-catalyzed heating, due to hydroxyl methyl or ether hydroxyl methyl and hydroxyl or carboxyl between the condensation reaction and crosslinking.

(2) The copolymer of acrylate containing hydroxyl, carboxyl, and secondary amine by isocyanate reaction can be crosslinked with a polyisocyanate and its addition. The synthetic properties of the pressure-sensitive adhesive obtained by this crosslinking method are excellent.

(3) cyclic guilt resin or polycyclic guilt compound can be used for acrylate copolymers containing amine, hydroxyl, and carboxyl groups without epoxy reaction crosslinking, while polyamine or polyanhydride can be used for acrylate copolymers containing epoxy group crosslinking.

(4) Using the reaction of alkoxy compounds and the cross-linked alkoxy compounds such as tetrabbutoxy titanium, tetrisopropoxy titanium, tri isopropoxy aluminum can be quickly esterified or alkoxy exchange reaction with the carboxyl group or hydroxyl group of acrylate copolymer at room temperature or low temperature.

(5) ionic cross-linking metal salts, such as acetic acid, caprylic acid, naphthenic acid, lauric acid, and other organic acid salts of polyvalent or monovalent metals such as zinc, lead, sodium, cobalt, and carboxyl acrylate copolymer crosslinking.