Processes for preparation of microspheres
First Claim
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1. In a process for the preparation of microspheres having a particulate core material encapsulated by a polymeric coating wherein the polymer is dissolved in a solvent in which the core material is not soluble and the polymer is precipated by phase separation to encapsulate the core material by the addition of phase separation agent to the polymer-core material-solvent system;
- the improvement which comprises lowering the temperature of said system from about -40°
to -100°
C. and then adding the phase separation agent to the polymer-core material-solvent system to cause phase separation of the polymer.
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Abstract
Microspheres, prepared by the low-temperature e.g., -40° to -100° C., phase separation of a polymer and a core material.
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Citations
45 Claims
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1. In a process for the preparation of microspheres having a particulate core material encapsulated by a polymeric coating wherein the polymer is dissolved in a solvent in which the core material is not soluble and the polymer is precipated by phase separation to encapsulate the core material by the addition of phase separation agent to the polymer-core material-solvent system;
- the improvement which comprises lowering the temperature of said system from about -40°
to -100°
C. and then adding the phase separation agent to the polymer-core material-solvent system to cause phase separation of the polymer. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10)
- the improvement which comprises lowering the temperature of said system from about -40°
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11. A process for the preparation of microspheres having a homogeneous mixture of a polymer and core material which comprises,
dissolving the polymer and core material in a solvent, lowering the temperature of the resultant solution to about -40° - to -100°
C., and adding a polymer-core material phase separation agent to the solution to precipate microspheres of a homogeneous mixture of the polymer and core material. - View Dependent Claims (12, 13, 14, 15, 16, 17, 18, 19, 20)
- to -100°
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21. In a process for the encapsulation of preformed microspheres having a particulate core material encapsulated by a polymeric coating wherein the polymer is dissolved in a solvent in which the microsphere is not soluble and the polymer is precipated by phase separation to encapsulate the microsphere by the addition of phase separation agent to the polymer-microsphere-solvent system;
- the improvement which comprises lowering the temperature of said system from about -40°
to -100°
C. and then adding the phase separation agent to the polymer-microsphere-solvent system to cause phase separation of the polymer. - View Dependent Claims (22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40)
- the improvement which comprises lowering the temperature of said system from about -40°
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41. A process for encapsulating a plurality of heterogeneous preformed microspheres consisting essentially of, dissolving a polymer in a solvent in which the preformed microspheres are not soluble, lowering the temperature to about -40°
- to -100°
C., adding the preformed microspheres to the polymer-solvent solution;
adding a phase separation agent to the polymer-microsphere-solvent system to cause phase separation of the polymer, coating the microspheres.
- to -100°
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42. A process for encapsulating a plurality of heterogeneous preformed microspheres consisting essentially of, dissolving a polymer and core material in a solvent in which the preformed microspheres are not soluble, lowering the temperature to about -40°
- to -100°
C., adding the preformed microspheres to the polymer-core material-solvent solution;
adding a phase separation agent to the polymer-core material-microsphere-solvent system to cause phase separation of the polymer, coating the microspheres.
- to -100°
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43. A process for encapsulating a plurality of heterogeneous preformed microspheres with a polymer coating having core material dispersed therein consisting essentially of, dissolving a polymer in a solvent in which the core material and the preformed microspheres are not soluble, lowering the temperature to about -40°
- to -100°
C., adding the core material and the preformed microspheres to the polymer-solvent solution;
adding a phase separation agent to the polymer-core material-microsphere-solvent system to cause phase separation of the polymer, coating the microspheres.
- to -100°
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44. A process for encapsulating preformed microspheres consisting essentially of, dissolving a polymer and core material in a solvent in which the preformed microspheres are not soluble, lowering the temperature to about -40°
- to -100°
C., adding the preformed microspheres to the polymer-core material-solvent solution;
adding a phase separation agent to the polymer-core material-microsphere-solvent system to cause phase separation of the polymer, coating the microspheres.
- to -100°
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45. A process for encapsulating preformed microspheres with a polymer coating having core material dispersed therein consisting essentially of, dissolving a polymer in a solvent in which the core material and the preformed microspheres are not soluble, lowering the temperature to about -40°
- to -100°
C., adding the core material and the preformed microspheres to the polymer-solvent solution;
adding a phase separation agent to the polymer-core material-microsphere-solvent system to cause phase separation of the polymer, coating the microspheres.
- to -100°
Specification