Encapsulation

A population of microcapsules wherein each microcapsule comprises a capsule core and a capsule shell, the capsule shell being hydrolysable characterized by the capsule shell containing polar hydrophilic and acid groups, the population of microcapsules made by an oil-in-water microencapsulation process comprising:

• a) dispersing a polymeric emulsifier and optionally an initiator in water to form a water phase;
• b) dispersing in one or more oil phases to form a composition comprising components i) to v):
• i). an initiator, and a core material,
• ii). a first multifunctional (meth)acrylate monomer having greater than one ester group on average in the monomer and having a hydrophilicity index of less than 20,
• iii). a second multifunctional (meth)acrylate monomer, the second multifunctional (meth)acrylate comprising a hydrophilic multifunctional polar monomer having a hydrophilicity index of at least 30 and said second multifunctional polar monomer comprising 50% or less of the capsule shell, wherein the first and second multifunctional (meth)acrylate monomers together comprise greater than 80% by weight of the capsule shell,
• iv). an acidic (meth)acrylate monomer or at least one oil soluble or dispersible acid or both, the acidic (meth)acrylate monomer having one or more groups which are selected from carboxy and sulfonic groups, and
• v). optionally from 0 to 50% by weight of the capsule shell of an aliphatic polyester, the aliphatic polyester having two or more of acrylate or methacrylate groups;
• c) emulsifying the composition comprising components i) to v) into the water phase under high shear agitation to form an oil-in-water emulsion comprising droplets of the core material and oil phase monomers dispersed in the water phase;
• and
• d) activating the initiator or initiators by heat or actinic radiation to react the monomers and optional aliphatic polyester thereby forming a capsule shell which is polymeric, surrounding the droplets of the core material;
• and wherein
• e) the microcapsules of the population of microcapsules have, when measured under controlled composting conditions over 30 days using enumeration analysis average rate of observed numeric loss in a hemocytometer counting chamber of at least 1% per day;
• wherein the capsule shell comprises a reaction product of an additional monomer having a functional group selected from a disulfide, an acetal, a hemiaminal, a thioacetal, a thioketal, a formate, a phosphoester, a phosphase, an anhydride or an orthoester monomer, said additional monomer based on total shell weight constituting from 0.1 to 50 wt % of the capsule shell.