Microencapsulation system

Claim 2

A PROCESS FOR THE FORMATION OF MICROCAPSULES HAVING NON-PROTEINACEOUS WALLS, IN THE ABSENCE OF COACERVATION, WHICH COMPRISES THE STEPS OF: A. FORMING A PRIMARY OIL-IN-WATER EMULSION, WHICH EMULSION COMPRISES A WATER-IMMISCIBLE OILY MATERIAL DISPERSED IN THE FORM OF MICROSCOPIC DROPLETS IN A COLLOIDAL SOLUTION OF A NON-PROTEINACEOUS, POLYMERIC EMULSIFYING AGENT HAVING ABOUT THE SAME HYDROPHIL-LIPOPHIL BALANCE AS THE OILY MATERIAL, SAID EMULSIFYING AGENT BEING SELECTED FROM THE GROUP CONSISTING OF POLYVINYL ALCOHOL, METHYLCELLULOSE, A COPOLYMER OF AN ETHYLENICALLY UNSATURATED MONOMER AND MALEIC ANHYDRIDE, AND GUAR GUM; AND B. FORMING AN IMPERMEABLE COATING AROUND SAID DISPERSED OIL DROPLETS SOLELY BY PROVIDING TO THE EMULSION A COMPOUND DIFFERENT FROM SAID EMULSIFYING AGENT AND REACTIVE THEREWITH TO FORM AN IMPERMEABLE COATING, SAID COMPOUND SELECTED FROM THE GROUP CONSISTING OF AN ALDEHYDE

Claim 3

The process of claim 1 wherein said emulsifying agent is polyvinyl alcohol or methylcellulose.

Claim 4

The process of claim 2 wherein said emulsifying agent is polyvinyl alcohol and said impermeable coating is formed by the addition of a borate.

Claim 5

The method of claim 3 wherein said borate is sodium borate.

Claim 6

The process of claim 2 wherein the emulsifying agent is methylcellulose.

Claim 7

The process of claim 5 wherein said impermeable coating is formed by the addition of an aldehyde or guar gum.

Claim 8

The process of claim 6 wherein said impermeable coating is formed by the addition of an aldehyde.

Claim 9

The process of claim 7 wherein said aldehyde is glyoxal or formaldehyde.

Claim 10

The process as defined in claim 6 wherein said impermeable coating is formed by the addition of guar gum.

Claim 11

A process as defined in claim 1 wherein said emulsifying agent is a copolymer of an ethylenically unsaturated monomer and maleic anhydride.

Claim 12

The process of claim 10 wherein said emulsifying agent is a copolymer of methyl vinyl ether and maleic anhydride.

Claim 13

A process as defined in claim 10 wherein said impermeable coating is formed by the addition of gum tragacanth or polyvinyl alcohol.

Claim 14

The process as defined in claim 10 wherein said impermeable coating is formed by the addition of ethylene diamine or ethanolamine.

Claim 15

The process as defined in claim 1 wherein said emulsifying agent is guar gum.

Claim 16

Pressure-rupturable microcapsules made according to the process of claim 1.

Claim 17

A process as defined in claim 14 wherein said impermeable coating is formed by the addition of a borate.

Claim 18

A process for the formation of microcapsules in the absence of coacervAtion which comprises forming a primary oil-in-water emulsion, which emulsion comprises a water-immiscible oily material dispersed in the form of microscopic droplets in a colloidal solution of a nonproteinaceous, polymeric emulsifying agent having about the same hydrophil-lipophil balance as the oily material, said emulsifying agent being a self cross-linking polymeric material comprising the performed reaction product of a formaldehyde condensation product and polyvinyl alcohol or methylcellulose, or a copolymer of maleic anhydride and an ethylenically unsaturated monomer, and permitting said self cross-linking polymeric material to react to form an impermeable coating around each of said droplets.

Claim 19

A process for the formation of microcapsules in the absence of coacervAtion which comprises forming a primary oil-in-water emulsion, which emulsion comprises a water-immiscible oily material dispersed in the form of microscopic droplets in a colloidal solution of a nonproteinaceous, polymeric emulsifying agent having about the same hydrophil-lipophil balance as the oily material, said emulsifying agent being a self cross-linking polymeric material comprising the performed reaction product of a formaldehyde condensation product and polyvinyl alcohol or methylcellulose, or a copolymer of maleic anhydride and an ethylenically unsaturated monomer, and permitting said self cross-linking polymeric material to react to form an impermeable coating around each of said droplets.

Claim 20

The process as defined in claim 17 wherein said self cross-linking emulsifying agent is the preformed reaction product of polyvinyl alcohol and urea-formaldehyde.

Claim 21

The process as defined in claim 17 wherein said self cross-linking emulsifying agent is the reaction product of methylcellulose and urea-formaldehyde.

Claim 22

Pressure-rupturable microcapsules made according to the process of claim 17.

Claim 23

A process for the formation of microcapsules in the absence of coacervation, which comprises the steps of: A. forming a primary oil-in-water emuulsion, which emulsion comprises a water-immiscible oily material dispersed in the form of microscopic droplets in a colloidal solution of a non-proteinaceous, polymeric emulsifying agent having about the same hydrophil-lipophil balance as the oily material, said emulsifying agent being a copolymer of methyl vinyl ether and maleic anhydride; and B. forming a impermeable coating around said dispersed oil droplets solely by providing gelatin to the emulsion under conditions of brisk agitation, said emulsifying agent being cross-linked by said gelatin so as to form an impermeable coating around each of said dispersed oil droplets, the ratio of said emulsifying agent to said gelatin being at least about 0.5 part by weight of said emulsifying agent per part of said gelatin.

Claim 24

A process for the formation of microcapsules in the absence of coacervation, which comprises the steps of: A. forming a primary oil-in-water emuulsion, which emulsion comprises a water-immiscible oily material dispersed in the form of microscopic droplets in a colloidal solution of a non-proteinaceous, polymeric emulsifying agent having about the same hydrophil-lipophil balance as the oily material, said emulsifying agent being a copolymer of methyl vinyl ether and maleic anhydride; and B. forming a impermeable coating around said dispersed oil droplets solely by providing gelatin to the emulsion under conditions of brisk agitation, said emulsifying agent being cross-linked by said gelatin so as to form an impermeable coating around each of said dispersed oil droplets, the ratio of said emulsifying agent to said gelatin being at least about 0.5 part by weight of said emulsifying agent per part of said gelatin.

Claim 25

Pressure-rupturable microcapsules made according to the process of claim 21.

Claim 26

A process for the formation of microcapsules in absence of coacervation, which comprises the steps of: A. forming a primary oil-in-water emulsion, which emulsion comprises a water-immiscible oily material dispersed in the form of microscopic droplets in a colloidal solution of a methylcellulose emulsifying agent; and B. forming an impermeable coating around said dispersed oil droplets solely by adding to the emulsion of an A-stage melamine formaldehyde condensation product which reacts with said methylcellulose emulsifying agent under conditions of brisk agitation so as to form a non-proteinaceous, impermeable coating, the ratio of said emulsifying agent to said condensation product in said emulsion being at least 0.5 part by weight of emulsifying agent per part of said condensation product.

Claim 27

A process for the formation of microcapsules in absence of coacervation, which comprises the steps of: A. forming a primary oil-in-water emulsion, which emulsion comprises a water-immiscible oily material dispersed in the form of microscopic droplets in a colloidal solution of a methylcellulose emulsifying agent; and B. forming an impermeable coating around said dispersed oil droplets solely by adding to the emulsion of an A-stage melamine formaldehyde condensation product which reacts with said methylcellulose emulsifying agent under conditions of brisk agitation so as to form a non-proteinaceous, impermeable coating, the ratio of said emulsifying agent to said condensation product in said emulsion being at least 0.5 part by weight of emulsifying agent per part of said condensation product.

Claim 28

Pressure-rupturable microcapsules made according to the process of claim 23.