Abstract: Organotin polymers for use in marine anti-fouling paints contain pendent groups having the general formula --O.CO.R.sup.1 CO.OSnR.sub.3 where R is C.sub.1 to C.sub.10 alkyl, aryl, aralkyl or alkaryl, and R.sup.1 is a saturated or unsaturated aliphatic or aromatic C.sub.2 to C.sub.10 group. The polymer may be made by reacting a hydroxyl-containing polymer, e.g. styrene/allyl alcohol, with a carboxylic acid anhydride under ring-opening conditions and reacting the resulting carboxyl-containing polymer with an organotin compound.

Abstract: Polymer aggregates in the form of discrete particles of controlled particle size below 150 microns maximum dimension which are themselves aggregates of primary particles of a polymer or polymers derived from at least one ethylenically unsaturated monomer together with from 0 to about 400%, by weight on the weight of the monomer, of an organic thickener compatible with the monomer, said aggregate particle containing from 0 to about 95% by weight of pigment and/or extender are made by providing an aqueous dispersion of the monomer and thickener, a hydrophilic colloid being present in the aqueous phase of the dispersion and pigment and/or extender optionally being present in either the aqueous phase or the disperse phase, introducing a polymerization initiator into the aqueous phase of the dispersion, and maintaining the dispersion under conditions of high shear and continuing polymerization to substantial completion thereof. The aggregates are useful in coating comositions, e.g. to provide a matt finish.

Abstract: An agitating apparatus comprising a support, a container supported by the support and rotatable relative to the support about a substantially vertical axis, an agitator within the container and co-operating drive means between the support and the upper part of the container for driving said agitator when the container is rotated about said axis.