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Chemical structure of polyacrylates

The basic components (monomers) of polyacrylates are acrylic acid esters. With the C=C double bonds, this molecule can be polymerized into long-chained polyacrylates. If, instead of acrylic acid esters, methacrylic acid esters are used, polymethacrylates are created.

Polyacrylates

Usually, it is not acrylic acid itself that is polymerized, it is the acrylic acid ester, whereby in the monomers the hydrogen atom of the -COOH group is replaced by a different R-group. Possible modifications are: alkyl-, polyether- and polyester- chains. The acid group can also be neutralized with an amine. Reactive groups (e.g. OH) can also be incorporated into the side chains; such modified acrylate additives can be integrated into the coating film matrix during the cross-linking reaction of the binder. The molecular weight can be varied over a wide range; the number of monomer units is typically between 40 and 800. Using just one type of monomer for the polymerization produces homopolymers, whereas co-polymers are created if several different types of monomers are used.

For liquid coatings, the polyacrylates are available either as a solvent-free additive (100 %) or in a diluted form (~50 %). For use in powder coatings, the polyacrylates are absorbed onto inert carriers (acrylate content ~60 %).