Anti-fouling compositions with a fluorinated alkyl- or alkoxy-containing polymer or oligomer

Abstract

An anti-fouling composition which comprises a cured or cross-linked polymer free of perfluoropolyether moieties and a fluid fluorinated alkyl- or alkoxy-containing polymer or oligomer. Preferably, the fluorinated alkyl- or alkoxy-containing polymer or oligomer comprises a repeating unit of the general formula: <paragraph lvl="0"><in-line-formula>-{[CFR-(CFR)m-(O)n]p-[CFR-O]q}-</in-line-formula>wherein n is 0 or 1, m is an integer from 0 to 4, R independently is H, F, Cl, Br, or CF3, and the ratio q/p is 0-10, and the fluorine-free polymer is an organosiloxane-containing polymer comprising a repeating unit of the general structure -[SiR1R2-O]-, wherein R1 and R2 are independently hydrogen, alkyl, aryl, aralkyl, or a vinyl group.

Description

[0001] This application claims the benefit of European Patent Application No. 01201071.6, filed Mar. 21, 2001, and U.S. Provisional Patent Application Ser. No. 60 / 294,028, filed May 29, 2001.[0002] 1. FIELD OF THE INVENTION[0003] The invention pertains to an anti-fouling composition which comprises a cured or cross-linked polymer free of perfluoropolyether moieties and a fluid fluorinated alkyl- or alkoxy-containing polymer or oligomer, and to a method for inhibiting fouling in an aquatic environment.[0004] 2. BACKGROUND OF THE INVENTION[0005] Man-made structures such as boat hulls, buoys, drilling platforms, dry dock equipment, oil production rigs, and pipes which are immersed in water are prone to fouling by aquatic organisms such as green and brown algae, barnacles, mussels, and the like. Such structures are commonly of metal, but may also comprise other structural materials such as concrete. This fouling is a nuisance on boat hulls, because it increases frictional resistance dur...

AI Technical Summary

Problems solved by technology

Man-made structures such as boat hulls, buoys, drilling platforms, dry dock equipment, oil production rigs, and pipes which are immersed in water are prone to fouling by aquatic organisms such as green and brown algae, barnacles, mussels, and the like.

This fouling is a nuisance on boat hulls, because it increases frictional resistance during movement through the water, the consequence being reduced speeds and increased fuel costs.

It is a nuisance on static structures such as the legs of drilling platforms and oil production rigs, firstly because the resistance of thick layers of fouling to waves and currents can cause unpredictable and potentially dangerous stresses in the structure, and, secondly, because fouling makes it difficult to inspect the structure for defects such as stress cracking and corrosion.

Such coatings, however, are being regarded with increasing disfavour because of the damaging effects such toxins may have if released into the aquatic environment.

The disadvantage of this anti-fouling system when applied to boat hulls is that although the accumulation of marine organisms is reduced, relatively high vessel speeds are needed to remove all fouling species.

For this reason silicone rubbers have gained limited commercial success and there is a need for improvement of the anti-fouling and fouling release properties of these environmentally benign coatings.