The British Petroleum Company, P.l.c.

Ronald Alfred Crump

Brian Peter Goldie

Prem Sagar Thukral

Colin Walter Parkes

Aleksander Jerzy Groszek

Colin Christopher McCain

Wax coatings for underwater surfaces, e.g. ship's hulls, contain as biocidal component, an organo-tin ester (preferably a tribydrocarbyl tin ester) of an oxidized wax or an aliphatic fatty acid. The oxidized wax may be an oxidized petroleum wax and the fatty acid a C.sub.12 -C.sub.30 acid. The ester may form 5-100% of the finished coating and the other wax component, if present, may be a conventional petroleum wax.

Biocidal composition

A biocidal composition suitable for use in marine anti-fouling coatings is a water-insoluble mineral having an internal pore structure, containing, within the pores a biocidal compound effective against marine growth. Preferred minerals are zeolites, particularly synthetic faujasites, and porous silicas; preferred biocidal compounds are organo-tin compounds. The compounds may be incorporated into anti-fouling paints e.g. epoxy, epoxy-coal tar and chlorinated rubber paints or wax coatings.

Biocidal compositions

Underwater surfaces are protected against weed and/or shell growth with a wax coating containing one or more biocides effective against weed and/or shell growth when dissolved or dispersed in wax. The biocides are preferably sea-water insoluble and may be fresh water soluble also. They are preferably thermally stable up to 150.degree. C and soluble in wax. Suitable biocides are Cu, Zn, Ni, Co, Mn or Sn salts of carboxylic acids or polyacrylic acids, or organic compounds having an active structure containing S, Cl, N or O. The coating may be 5-500 micrometers thick.

Process of protecting underwater surfaces with a wax coating containing

Process for making a catalyst precursor by heating an inorganic oxide support with a titanium compound at a temperature in the range 150.degree. to 1200.degree. C and then retreating with titanium one or more times by alternately adding a hydroxyl compound (e.g. water) and titanium compound and heating at 150.degree. to 1200.degree. C. The precursor can be used to make a useful ethylene polymerization catalyst by adding a chromium compound and heat activating at a temperature in the range 100.degree. to 1200.degree. C.

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Horsham, United Kingdom

Ronald Alfred Crump