Teknologisk Institut

Stefan Holberg

Claus Bischoff

A curable coating composition and the use, especially in heat exchangers, for heating and/or cooling water, in particular tap water, is described. The curable coating comprises, based on solids after curing, 35-80% by weight of an epoxysilane according to the general structure 1 and/or its hydrolysation and/or condensation products, 1: RRSiRwith R1 being 3-glycidyloxypropyl, Rbeing methyl, Rbeing alkyloxy or acyloxy, a being 0, 1 or 2 and b being 3&#x2212;a and 20-65% by weight of a blocked polyisocyanate and optionally further components. The coating provides improved corrosion protection on aluminium surfaces, reduces limescale formation on heat exchanger surfaces and is able to withstand lateral and/or temporal temperature gradients when coated on heat exchanging surfaces.

Coating composition, method for making the coating and use thereof

A cross-linkable coating composition comprises (i) one or more silanes having either at least three hydrolysable groups, or at least two hydrolysable groups and at least one organofunctional group capable of forming chemical bonds upon curing, wherein (i.a) the sum of said silanes constitutes at least 20% of the total mass of the coating compositions combined solids and silanes, and (i.b) said silanes are possibly partly or completely hydrolyzed and possibly partly condensed, and (ii) at least one low surface energy additive, wherein (ii.a) said low surface energy additive comprises polydimethylsiloxane chemically bonded to at least one functional group, (ii.b) said functional group is configured for the polydimethylsiloxane moiety to cross-link with said coating composition, (ii.c) said polydimethylsiloxane constitutes 0.01% to 15% of the mass of said cured coating, when said coating composition is cured, and (ii.d) said polydimethylsiloxane moiety has a molecular weight of more than 1600 g/mol.

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Aarhus C, Denmark

Stefan Holberg