Process of microencapsulation and products thereof

• US 4,211,668 A
• Filed: 04/24/1978
• Issued: 07/08/1980
• Est. Priority Date: 03/07/1977
• Status: Expired due to Term

• Current Assignee: Fairfield National Bank Southeast 3RD and Delaware Street Wayne IL
• Original Assignee: Thalatta Incorporated
• Inventors: Tate, Clarence R.
• Primary Examiner(s): Parr, E. Suzanne
• Application Number:
  US05/899,580
• Time in Patent Office: 806 Days
• Field of Search: 252/316, 264/4
• US Class Current: 428/402.2
• CPC Class Codes: B01J 13/20 After-treatment of capsule walls, e.g. hardening
• CPC Class Codes: B41M 5/165 characterised by the use of microcapsules; Special solvents for incorporating the ingredients
• CPC Class Codes: Y10T 428/2984 Microcapsule with fluid core [includes liposome]
• CPC Class Codes: Y10T 428/2987 Addition polymer from unsaturated monomers only

Abstract

This invention relates to a process for making microscopic size capsules from an emulsion having an inner oily or hydrophobic phase (material to be encapsulated) and an outer hardenable hydrophilic phase. The process is characterized by the step of contacting said emulsion with a break-up fluid capable of dividing said emulsion into substantially separate capsules having an inner hydrophobic phase and an outer hardenable hydrophilic phase; and then hardening the hydrophilic phase of said capsules to form microscopic size capsules or microencapsulations.

The separated capsules can contain clusters of capsules, or they may be made as separate, individual capsules. In the preferred embodiment, the break-up fluid contains a surfactant capable of enhancing the break-up function of the fluid so that the separated capsules are predominately individual capsules.

This invention also relates to microscopic size capsules formed by this process.

Claims

1. A process of making microcapsules having transparent capsule shells containing a hydrophobic liquid which is characterized by:

1. forming an emulsion comprising an outer hydrophilic phase and droplets of a hydrophobic liquid suspended therein as the inner hydrophobic phase, said outer hydrophilic phase comprising a hardenable wall forming polymeric material dissolved in an aqueous solvent;

2. contacting said emulsion with a break-up fluid which is not a solvent for said polymeric material, which is substantially immiscible with the polymeric material solvent, and which is capable of dividing said emulsion into separate capsules having an inner hydrophobic phase and an outer hydrophilic phase;

3. then hardening the hydrophilic phase of said capsules with a hardening liquid which is substantially miscible with the break-up bath, which is not a solvent for said polymeric material, and which is, of itself or in combination with another liquid, substantially immiscible with said polymeric material solvent.

2. The process of claim 1 where the break-up fluid contains a hydrocarbon solvent;

a terpene;

vegetable, or mineral oils, or combinations thereof.

3. The process of claim 1 where the hardening medium contains an alcohol, a hydrocarbon solvent, a terpene or combinations thereof.

4. The process of claim 1 where the break-up fluid contains a surfactant.

5. The process of claim 1 where the hydrophilic exterior phase contains a gelatin.

6. The process of claim 2 where the break-up fluid contains a surfactant.

7. The process of claim 3 where the break-up fluid contains a surfactant.

8. The product of claim 1.

9. The product of claim 2.

10. The product of claim 3.

11. The product of claim 4.

12. The product of claim 5.

13. The product of claim 6.

14. The product of claim 7.