Microcapsules containing a gas-generating photolabile ketoacid or ketoester and uses thereof

A non-diffusive microcapsule comprising:

• A. a core comprising:
• an oil phase;
• at least one photolabile α-ketoacid or α-ketoester capable of generating, upon exposure to light a gas selected among the group consisting of CO and CO2 and being of formula
• wherein R′ represents:
• i) a C1-16 hydrocarbon group optionally comprising one to four oxygen, sulphur or nitrogen atoms, provided that no heteroatom is directly connected to the CO group;
• or
• ii) a group of formula R1′(CO—COOR2)n wherein R2 has the same meaning as below and R1′ is a C2-10 hydrocarbon group, optionally comprising one or two oxygen or nitrogen atoms, provided that no heteroatom is directly connected to the CO group, wherein R1′ is linked to the keto functional group of the α-ketoacid or α-ketoester and wherein n is an integer comprised between 1 and 4;
• and wherein R2 represents either a hydrogen atom or an alkaline metal ion, or a primary or secondary group which is:
• a) a C1-4 hydrocarbon group optionally comprising one or two oxygen or nitrogen atoms;
• or
• b) a C5-22 hydrocarbon group optionally comprising one to ten oxygen atoms or one to two nitrogen atoms;
• provided that said C5-22 hydrocarbon group is such as that the corresponding aldehyde or ketone of the O—R2 moiety is an odorless compound;
• or
• c) a group of formula R2′(OOC—CO—R1), wherein R1 has the same meaning as above and R2′ is a C2-12 hydrocarbon group optionally comprising one to six oxygen atoms and wherein R2′ is linked to the ester functional group of the α-ketoester, and wherein n is an integer comprised between 1 and 4;
• provided that at least one of R1 or R2 is a group as defined in i) or a) or b) respectively;
• and
• optionally comprising at least one photo-catalyst;
• and
• B. a shell surrounding said core formed by interfacial polymerization or by a phase separation process induced by polymerization or by coacervation.