US4419383A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Method for individually encapsulating magnetic particles
Assignee: Magnavox Electronic Systems Co
•
Filing: 1983-04-11
•
Granted: 1983-12-06
•
Expires: 2003-04-11
Abstract
Abstract A method for encapsulating magnetic particles by enclosure within oil drops, mixing in an aqueous solution and dispersing the oil drops with the enclosed particles by application of an alternating magnetic field. The dispersed and oil covered particles are microencapsulated with at least one type of polymer.
Inventors
- 👤 Lawrence L. Lee
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-29 16:21
CPC Classifications
H; H01; H01F; H01F1/00; H01F1/44; B; B01; B01J; B01J13/00; B01J13/02; B01J13/04; G; G09; G09F; G09F9/00; G09F9/30; G09F9/37; G09F9/375
Claims Analysis
Total Claims: 17
Claim 1
Independent Claim
133 words
A method for dispersing a preselected average number of magnetized particles, the particles being enclosed in a discrete amount of internal phase, comprising the following steps: immersing the particles in a liquid internal phase; suspending internal phase drops containing the immersed particles in a liquid continuous phase; mechanically agitating the continuous phase to provide initial dispersing of said particles and forming smaller drops with a reduced number of particles in each drop; applying a varying magnetic field to said suspension for further dispersing of said particles into smaller drops with a reduced number of particles in each drop, the frequency of said field variations being selected according to the desired number of particles in individual drops; microencapsulating individual ones of said drops to form capsules containing drops in which said particles are rotatable.
Claim 2
Independent Claim
133 words
A method for dispersing a preselected average number of magnetized particles, the particles being enclosed in a discrete amount of internal phase, comprising the following steps: immersing the particles in a liquid internal phase; suspending internal phase drops containing the immersed particles in a liquid continuous phase; mechanically agitating the continuous phase to provide initial dispersing of said particles and forming smaller drops with a reduced number of particles in each drop; applying a varying magnetic field to said suspension for further dispersing of said particles into smaller drops with a reduced number of particles in each drop, the frequency of said field variations being selected according to the desired number of particles in individual drops; microencapsulating individual ones of said drops to form capsules containing drops in which said particles are rotatable.
Claim 3
Dependent Claim
30 words
The method of claim 1 including the step of mechanically agitating the continuous phase after the microencapsulating step, to keep the capsules separated while the capsule shell walls become smooth.
Claim 4
Dependent Claim
15 words
The method of claim 1 wherein said mechanical agitating step comprises stirring said continuous phase.
Claim 5
Dependent Claim
58 words
The method of claim 1 wherein said microencapsulation step comprises injecting an acidic composition into said continuous phase to form a two phase mixture, one phase being a first solution of the capsule shell forming material and a second phase being a coacervation of a more concentrated solution than said first solution of a capsule shell forming material.
Claim 6
Independent Claim
135 words
A method for dispersing a preselected average number of magnetized particles, the particles being enclosed in a discrete amount of internal phase, comprising the following steps: immersing the particles in a liquid internal phase; suspending internal phase drops containing the immersed particles in a liquid continuous phase; controlling at least one of the temperature, pH, and concentrations of the continuous phase in order to initiate formation of the capsule shell walls; varying the magnetic field to said suspension for further dispersing of said particles into smaller drops with a reduced number of particles in each drop, the frequency of said field variations being selected according to the desired number of particles in individual drops; microencapsulating individual ones of said drops to form capsules containing drops in which said particles are rotatable; strengthening the capsule walls.
Claim 7
Independent Claim
135 words
A method for dispersing a preselected average number of magnetized particles, the particles being enclosed in a discrete amount of internal phase, comprising the following steps: immersing the particles in a liquid internal phase; suspending internal phase drops containing the immersed particles in a liquid continuous phase; controlling at least one of the temperature, pH, and concentrations of the continuous phase in order to initiate formation of the capsule shell walls; varying the magnetic field to said suspension for further dispersing of said particles into smaller drops with a reduced number of particles in each drop, the frequency of said field variations being selected according to the desired number of particles in individual drops; microencapsulating individual ones of said drops to form capsules containing drops in which said particles are rotatable; strengthening the capsule walls.
Claim 8
Dependent Claim
37 words
The method of claim 5 wherein said step of varying the magnetic field comprises applying an initial field frequency and strength and after the microencapsulation step, applying a second field of reduced frequency and reduced field strength.
Claim 9
Dependent Claim
41 words
The method of claim 6 wherein said initial frequency is about 430 Hz and said initial field strength is about 400 gauss and said second frequency is less than 100 Hz and said second field strength is less than 100 gauss.
Claim 10
Dependent Claim
26 words
The method of claim 1 including the step of flowing said internal phase drops suspended in the continuous phase through a magnetic field of increasing frequency.
Claim 11
Dependent Claim
55 words
The method of claim 1 wherein said internal phase comprises by weight 4 parts of paraffin oil and 1 part kerosene, with 5% trimesoyl chloride and 4% Alrosperse 100 by weight added, and the continuous phase comprises 60 gm of 2% solution of 290 Bloom, pig-skin gelatin and 0.15 cc of 40% sodium hexameta phosphate.
Claim 12
Dependent Claim
70 words
The method of claim 1 wherein the step of applying a varying magnetic field comprises the continuous flow step of flowing said internal phase drops suspended in the continuous phase through an elongated tube and applying a separate varying magnetic field to each of a plurality of longitudinally spaced portions of said tube, the magnetic field frequency applied to said portions sequentially downstream of said tube being correspondingly sequentially increasing.
Claim 13
Dependent Claim
39 words
The method of claim 10 wherein said continuous flow step includes increasing the magnetic field frequency of each of said portions to the next successive of said portions downstream of said tube by a factor of less than two.
Claim 14
Dependent Claim
26 words
The method of claim 1 wherein said step of mechanically agitating the continuous phase continues throughout the steps of applying a varying magnetic field and microencapsulating.
Claim 15
Dependent Claim
37 words
The method of claim 5 wherein the controlling step comprises reducing the temperature of the continuous phase from an initial temperature to a lower second temperature prior to suspending the internal phase drops in the continuous phase.
Claim 16
Dependent Claim
34 words
The method of claim 13 wherein said initial temperature is in the range of 50° C. to 55° C., said second temperature is approximately 41° C., and said final temperature is about 10° C.
Claim 17
Dependent Claim
39 words
The method of claim 13 wherein said strengthening step comprises quenching the continuous phase containing the drops from said second temperature to a final temperature lower than said second temperature whereby the coacervate capsule shell walls become a gel.
References Cited (Backward Citations)
No citation records indexed.
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1986-12-05 | 1987-06-06 | 1987-12-06 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1990-12-05 | 1991-06-06 | 1991-12-06 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1994-12-05 | 1995-06-06 | 1995-12-06 | $7700.00 | Window Closed / Lapsed |