Akzo Nobel Coatings International B.v.

Imperial Chemical Industries Limited

Neal St John Williams

Stephen Arthur Wheeler

Robert David Bradley

Chris Lampard

Stephen Barry Downing

Jeff T Carter

Steve Quinn

An aqueous dispersion of pigmented opacifying polymer particles, the particles comprising: i. an inorganic core comprising dispersed inorganic pigment particle and a dispersant ii. a first layer of base-swellable polymer comprising acid groups encapsulating the core iii. a second layer of non-base-swellable polymer encapsulating the first layer wherein the dispersant comprises or consists of hydroxyl moieties; and carboxyl groups derived from itaconic acid.

Opacifying polymer particles

A method of preparing an aqueous dispersion of opacifying polymer particles containing inorganic pigment particles therein is disclosed. The method yields hollow polymer particles containing pigment particles therein using a non-RAFT emulsion polymerization process by free radical polymerization. The technique is much faster and simpler than known RAFT methods.

Method of making opacifying polymer particles

A method of making a polymerisable ethylenically unsaturated macromonomer comprising the steps of: i) providing a chosen unsaturated non-mineral oil or a mixture of unsaturated non-mineral oils having a first blend of triglycerides, ii) treating the mixture of oils with a transesterification catalyst to produce a second blend of triglycerides different to the first, iii) reacting the second blend of triglycerides with an enophile having an acid, ester or anhydride moiety to form an adduct, iv) reacting the adduct with an ethylencially unsaturated monomer having a moiety reactive with the acid, ester or anhydride moiety of the enophile to form an intermediate, v) reacting the intermediate of step (iv) with a chain extender having at least two moieties reactive with the acid, ester or anhydride moiety of the enophile to form the ethylenically unsaturated macromonomer.

Method of making triglyceride macromonomers

A polymerisable ethylenically unsaturated macromonomer being the reaction product of: i) an adduct formed from the reaction of an unsaturated non-mineral oil reacted with an enophile having an acid, ester or anhydride moiety and ii) an ethylenically unsaturated monomer having a moiety reactive with the acid, ester or anhydride moiety of the enophile and iii) a chain extender material having at least two moieties reactive with the acid, ester or anhydride moiety of the enophile.

Triglyceride macromonomers

A process for making poly(urethane-urea)/addition polymer composite particles which avoids the need to use a highly viscous solution of a prepolymer for the poly(urethane-urea). The process comprises dissolving diol and di-isocyanate in addition polymerisable monomers and allowing them to co-react but for only long enough to form a precursor for the prepolymer which is of a lower molecular weight than the prepolymer so that the precursor forms a solution of much lower viscosity. This lower viscosity solution is then dispersed in water to give droplets in which the co-reaction continues and completes the formation of the prepolymer whilst water diffuses into the droplets and causes chain extension to create the poly(urethane-urea) particles. The addition polymerisable monomers in the dispersed droplets spontaneously diffuse into the poly(urethane-urea) particles where they are subjected to a conventional free radical addition polymerisation process whereupon composite the poly(urethane-urea)/addition polymer particles are formed. The composite particles can be obtained as stable aqueous dispersions optionally containing less than 3 wt % organic solvent and over 40 wt % of the composite particles.

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Warfield, United Kingdom

Neal St John Williams