Oil-in-water capsule manufacture process and microcapsules produced by such process
View Patent ↗A novel method of forming oil in water process is disclosed. According to the invention process are obtained by steps comprising dispersing an oil soluble amine modified polyfunctional polyvinyl monomer and an oil soluble bi- or polyfunctional vinyl monomer along with a thermal or UV free radical initiator (optionally included in one or both of the oil or water phases) and an organic acid into an internal phase oil; heating or UV exposing for a time (and temperature) sufficient to oligomerize the amine modified polyfunctional polyvinyl monomer and oil soluble bi- or polyfunctional vinyl monomer forming a pre-polymer. Thereafter the process involves adding to the oil phase oil a water phase comprising a dispersion in water of an anionic emulsifier (and optionally initiator), and adding an emulsifying agent. Emulsification of the oil phase into the water phase (O/W) is controlled through the quantity of water employed. The emulsion is then UV exposed or heated for a time (and temperature) sufficient to decompose the free radical initiators in the oil and/or water phases; thereby forming microcapsule wall material at the interface of the water and oil phases.
1. A process for preparing process encapsulating an oil phase, the process comprising:
dispersing an oil soluble amine modified polyfunctional polyvinyl monomer or oligomer and an oil soluble bi- or polyfunctional vinyl monomer or oligomer along with a free radical initiator and an organic acid and a core material into an internal phase oil; the organic acid selected from the group consisting of monoalkyl maleate, alkyl benzene sulfonic acid, and alkyldiphenyloxide sulfonic acid;
a first heating step comprising, heating for a time and temperature sufficient to oligomerize or further oligomerize the amine modified polyfunctional polyvinyl monomer or oligomer and oil soluble bi- or polyfunctional vinyl monomer or oligomer forming a pre-polymer;
adding to the internal phase oil a water phase in excess comprising a dispersion in water of a polyacrylic or polymethacrylic acid, a free radical initiator, and an emulsifying agent;
emulsifying the oil phase into the water phase forming droplets of the oil phase dispersed in the water phase;
a second heating step comprising, heating for a time and temperature sufficient to decompose the free radical initiator in the oil and water phases;
thereby forming microcapsule wall material at the interface of the water and oil phases, the process encapsulating the oil phase droplets; and, a third heating step comprising heating to a temperature equal to or greater than the second heating step temperature for a time sufficient to polymerize the wall material.
2. The process according to claim 1 wherein the oligomerization is accomplished by heating, in the first heating step, is to at least 55° C. for at least one hour to form the prepolymer.
3. The process according to claim 1 wherein the amine modified polyvinyl monomer is selected from amine modified ethoxylated trimethylol propane triacrylate, diacrylate amine, dimethacrylate amine, amine modified polyether acrylate, and amine modified polyether methacrylate.
4. The process according to claim 1 wherein the bi- or polyfunctional vinyl monomer or oligomer is selected from diethylene glycol dimethacrylate pentaerythritoltriacrylate, trimethylol propane triacrylate, urethane diacrylate, urethane dimethacrylate, ethoxylated aliphatic difunctional urethane acrylate, and ethoxylated aliphatic difunctional urethane methacrylate.
5. The process according to claim 1 wherein the emulsifier is selected from polymethacrylic acid, acrylic acid alkyl acrylate copolymer, alkyl succinamates, alkyl aryl sulfonic acid salts or alkyl sulfate salts.
6. The process according to claim 1 wherein the third heating step is to at least 90° C. for at least three hours.
7. The process according to claim 1 wherein the organic acid is selected from a monoalkylmaleate, a carboxy acid, or an organic sulfonic acid.monomethyl maleate, monoethyl maleate, or monobutyl maleate.
8. A process for preparing process encapsulating an oil phase, the process comprising:
dispersing an oil soluble amine modified polyfunctional polyvinyl monomer or oligomer and an oil soluble bi- or polyfunctional vinyl monomer or oligomer along with a free radical initiator and an organic acid into an internal phase oil; the organic acid selected from the group consisting of monoalkyl maleate, alkyl benzene sulfonic acid, and alkyl diphenyloxide sulfonic acid;
a first heating step comprising heating for a time and temperature sufficient to decompose at least some portion of the free radical initiator and thereby oligomerize the amine modified polyfunctional polyvinyl monomer or oligomer and oil soluble bi- or polyfunctional vinyl monomer or oligomer forming a pre-polymer,
adding to the internal phase oil a water phase in excess, the water phase comprising a dispersion in water of an anionic emulsifier,
emulsifying the oil phase into the water phase forming droplets of the oil phase dispersed in the water phase;
a second heating step comprising heating for a time and temperature sufficient to decompose the remaining portion of free radical initiator thereby forming microcapsule wall material from prepolymer at the interface of the water and oil phases;
and a third heating step comprising heating to a temperature equal to or greater than the second heating step temperature for a time sufficient to polymerize the wall material.
9. The process according to claim 8 wherein a free radical initiator is selected from an azo or peroxy initiator.
10. The process according to claim 8 wherein the oligomerization is accomplished by heating, in the first heating step, to at least 55° C. for at least one hour to form the prepolymer.
11. The process according to claim 8 wherein the amine modified polyvinyl monomer is selected from amine modified ethoxylated trimethylol propane triacrylate, diacrylate amine, dimethacrylate amine, amine modified polyetheracrylate, and amine modified polyethermethacrylate.
12. The process according to claim 8 wherein the bi- or polyfunctional vinyl monomer or oligomer is selected from a polyacrylate, a polymethacrylate, a dimethacrylate, a diacrylate, a triacrylate, diethylene glycol dimethacrylate, pentaerythritoltriacrylate, trimethylol propane triacrylate, urethane diacrylate, urethane dimethacrylate ethoxylated aliphatic difunctional urethane acrylate, and ethoxylated aliphatic difunctional urethane methacrylate.
13. The process according to claim 8 wherein the emulsifier is selected from polyacrylic acid, polymethacrylic acid, acrylic acid alkyl acrylate copolymer, alkyl succinamates, alkylaryl sulfonic acid salts or alkyl sulfate salts.
14. The process according to claim 8 wherein the organic acid is selected from carboxy acid, organic sulfonic acid, or monoalkyl maleate.
15. The process according to claim 8 wherein the third heating step comprises heating to at least 90° C. for at least three hours.
16. The process according to claim 8 wherein a second initiator is added in addition to the water phase and wherein the initiator in the oil phase decomposes at a first temperature and the initiator in the water phase decomposes at a second temperature.
17. A process for preparing process encapsulating an oil phase, the process comprising:
providing an internal phase oil and a water phase containing a free radical initiator in at least one of said phases,
dispersing an oil soluble amine modified polyfunctional polyvinyl monomer or oligomer and an oil soluble bi- or polyfunctional vinyl monomer or oligomer, a core material, and an organic acid into the internal phase oil; the organic acid selected from the group consisting of monoalkyl maleate, alkyl benzene sulfonic acid, and alkyl diphenyloxide sulfonic acid;
adding to the internal phase oil the water phase in excess, said water phase further comprising a dispersion in water of an anionic emulsifier,
emulsifying the oil phase into the water phase forming droplets of the oil phase in the water phase;
a first heating step comprising, heating for a time and temperature sufficient to decompose the free radical initiator in at least the oil or water phase, and sufficient to oligomerize or further oligomerize the amine modified polyfunctional polyvinyl monomer and oil soluble bi- or polyfunctional vinyl monomer or oligomer forming a pre-polymer and thereby forming microcapsule wall material at the interface of the water and oil phases;
and a second heating step comprising heating to a temperature equal to or greater than the first heating step temperature for a time sufficient to polymerize the wall material.
18. The process according to claim 17 wherein a free radical initiator is selected from an azo or peroxy initiator.
19. The process according to claim 17 wherein the first heating step is heating to at least 55° C. for at least one hour.
20. The process according to claim 17 wherein the amine modified polyvinyl monomer is selected from amine modified ethoxylated trimethylol propane triacrylate, diacrylate amine, dimethacrylate amine, amine modified polyetheracrylate, and amine modified polyethermethacrylate.
21. The process according to claim 17 wherein the bi- or polyfunctional vinyl monomer or oligomer is selected from a polyacrylate, a polymethacrylate, a dimethacrylate, a diacrylate, a triacrylate, diethylene glycol dimethacrylate, pentaerythritoltriacrylate, trimethylol propane triacrylate, urethane diacrylate, urethane dimethacrylate ethoxylated aliphatic difunctional urethane acrylate, and ethoxylated aliphatic difunctional urethane methacrylate.
22. The process according to claim 17 wherein the emulsifier is selected from polyacrylic acid, polymethacrylic acid, acrylic acid alkylacrylate copolymer alkyl succinamates, alkylaryl sulfonic acid salts or alkyl sulfate salts.
23. The process according to claim 17 wherein the organic acid is selected from carboxy acid, organic sulfonic acid, or monoalkyl maleate.
24. The process according to claim 17 wherein the second heating step comprises heating to at least 90° C. for at least three hours.
25. The process according to claim 17 wherein a second initiator is added in addition to the water phase and wherein the initiator in the oil phase decomposes at a first temperature and the initiator in the water phase decomposes at a second temperature.
26. The process according to claim 17 wherein the initiators in the oil phase and the water phase are the same or different.