Controlled release microcapsules

A method of making microcapsules whose shell wall comprises on one surface a first (meth)acrylate polymer and on its other surface a second (meth)acrylate polymer, said first (meth)acrylate polymer derived from an aqueous phase (meth)acrylate polymer wall forming composition and said second (meth)acrylic polymer derived from an oil phase first (meth)acrylate polymer wall forming composition, and an intermediate region comprising an interpenetrating network and/or copolymer of the two wall forming compositions, said method comprising:

• (i) forming an oil-in-water or a water-in-oil emulsion of the two (meth)acrylate polymer wall forming compositions,
• (ii) subjecting, the emulsion to conditions for concurrently, at last in part, polymerizing the wall forming materials of each of the oil phase and water phase, and
• (iii) allowing the reaction to continue until the microcapsules of desired wall thickness are attained, wherein said process further comprises
• (I) the step of oligomerizing and/or prepolymerizing some or all of the (meth)acrylate polymer wall forming components of the oil phase composition, the aqueous phase composition or both prior to forming the emulsion, (II) the step of oligomerizing and/or prepolymerizing some or all of the (meth)acrylate polymer wall forming components of the oil phase composition, the aqueous phase composition or both subsequent to forming the emulsion but prior to initiating wall formation, or (III) using oligomers and/or prepolymers of the wall forming components of the oil phase composition, the aqueous phase composition or both.