CONTINUOUS ENCAPSULATION AND DEVICE THEREFOR

• US 3,816,331 A
• Filed: 07/05/1972
• Issued: 06/11/1974
• Est. Priority Date: 07/05/1972
• Status: Expired due to Term

• Current Assignee: WTA, Inc. (Franklin Resources Incorporated)
• Original Assignee: Donald B. Clark, George T. Brown Jr, Robert G. Bayless
• Inventors: Brown, George T. Jr., Bayless, Robert G., Clark, Donald B.
• Primary Examiner(s): Lovering, Richard D.
• Application Number:
  US05/268,996
• Time in Patent Office: 706 Days
• Field of Search: 252/316,314,359R 117/1A 264/4 138/42 259/4,11,18,36,DIG.24,DIG.30
• US Class Current: 427/213.3
• CPC Class Codes: B01J 13/046 combined with gelification or coagulation
• CPC Class Codes: B01J 13/06 by phase separation
• CPC Class Codes: Y10S 516/924 Significant dispersive or manipulative operation or step in making or stabilizing colloid system
• CPC Class Codes: Y10T 428/2984 Microcapsule with fluid core [includes liposome]
• CPC Class Codes: Y10T 428/2987 Addition polymer from unsaturated monomers only
• CPC Class Codes: Y10T 428/2989 Microcapsule with solid core [includes liposome]

Abstract

Continuous encapsulation in a liquid capsule manufacturing vehicle by a process of liquid-liquid phase separation is disclosed. The continuous encapsulation is performed in a capsule manufacturing conduit which has a plurality of material introduction ports at spaced positions and a single material exit port and has a substantially constant cross-sectional shape and area throughout its length. Individual components required for encapsulating are continuously fed into the conduit at separate introduction ports and material in the conduit is maintained in turbulent-flow, steady-state, condition and emerges from the material exit port as a dispersion of minute capsules in an aqueous vehicle. The introduction ports comprise reduced-diameter needles intersecting the conduit as turbulence-inducing bends.

Claims

2. The process of claim 1 wherein the solution is aqueous.

3. The process of claim 1 wherein the solution utilizes organic solvent.

4. The process of claim 1 wherein there is the additional step of:

introducing capsule wall hardening material into the solution of (a), the capsule core material of (b) and the phase-separation-inducing material of (c).

5. A device for continuously manufacturing minute capsules, in operation, comprising:

a. a capsule manufacturing conduit having a plurality of spaced-apart material introduction ports and only a single exit port and having introduced sequentially along the conduit and flowing therethrough in a turbulent, steady-state manner, an aqueous solution of polymeric capsule wall material, substantially water insoluble intended capsule core material and liquid-liquid phase separation-inducing material to yield an intimate mixture of encapsulating components, wherein the introduction ports each comprise a tee with a cross-bar and a leg positioned to yield a bend in the conduit of greater than 45* to enhance turbulent flow, an incoming main stream being conducted into the leg, an exiting main stream being conducted out one end of the cross-bar, and a reduced-diameter induction needle for introduction of each capsule manufacturing component located concentric with the other end of the cross-bar, extending inward to just beyond the bend in the conduit and with an incoming additive stream being conducted through the needle and into the turbulent main stream; and

b. pumping means operatively attached to the conduit and maintaining substantially steady-state flow in the conduit at a rate such that;

(i) DV Rho / Mu is greater than 4,000 where D is the conduit diameter, V is the velocity of a cross-section front of the vehicle moving through the conduit, Rho is the density of the vehicle and Mu is the viscosity of the vehicle; and

(ii) DV Rho / Mu is less than 4,000 where D is the capsule diameter, V is the velocity of an individual capsule moving through the conduit, Rho is the density of the capsules and Mu is the viscosity of the ungelled capsule wall;

whereby the intimate mixture is conducted through the conduit and minute capsules leave the conduit and at any given cross-sectional location in the conduit the conditions are constant as a function of time.

6. A device for continuously manufacturing minute capsules at a rapid rate in a liquid capsule manufacturing vehicle comprising:

a. a closed conduit having a plurality of sequentially spaced introduction ports to receive components of an encapsulating system and an exit port for release of capsules and the vehicle, said conduit having a length of more than 10 feet, an inside diameter of less than 1 inch and a substantially constant cross-section, wherein the introduction ports each comprise a tee with a cross-bar and a leg positioned to yield a bend in the conduit of greater than 45* to enhance turbulent flow, an incoming main stream being conducted into the leg, an exiting main stream being conducted out one end of the cross-bar, and a reduced-diameter induction needle for introduction of each capsule manufacturing component located concentric with the other end of the cross-bar, extending inward to just beyond the bends in the conduit and with an incoming additive stream being conducted through the needle and into the turbulent main stream; and

b. pumping means sealed to ports of the conduit to maintain substantially turbulent flows and substaNtially steady-state conditions in the conduit such that;

(i) DV Rho / Mu is greater than 4,000 where D is the conduit diameter, V is the velocity of a cross-section front of the vehicle moving through the conduit, Rho is the density of the vehicle and Mu is the viscosity of the vehicle; and

(ii) DV Rho / Mu is less than 4,000 where D is the capsule diameter, V is the velocity of an individual capsule moving through the conduit, Rho is the density of the capsules and Mu is the viscosity of the ungelled capsule wall.