US4233178A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Micro-capsules and method for their production
Assignee: Mitsubishi Paper Mills Ltd
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Filing: 1978-09-27
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Granted: 1980-11-11
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Expires: 1998-09-27
Abstract
Abstract A hydrophobic material such as an oil solution of a dye is dispersed by the aid of a styrene-maleic anhydride copolymer to form an aqueous dispersion, then a melamine-formaldehyde precondensate is added into said dispersion and the mixture is heated and hardened to produce micro-capsules. These micro-capsules are proof against leakage or oozing of the hydrophobic material and uniform in shape and can serve excellently, for example, as dye capsules used for non-carbon paper.
Inventors
- 👤 Mitsuru Fuchigami
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-23 19:35
CPC Classifications
B; B01; B01J; B01J13/00; B01J13/02; B01J13/06; B01J13/14; B01J13/18; Y; Y10; Y10S; Y10S428/00; Y10S428/914; Y10T; Y10T428/00; Y10T428/29; Y10T428/2982; Y10T428/2984; Y10T428/2985
Claims Analysis
Total Claims: 9
Claim 1
Independent Claim
63 words
A method of producing micro-capsules containing a hydrophobic material comprising the steps of dispersing the hydrophobic material in an acidic aqueous solution of a styrene-maleic anhydride copolymer as dispersing agent or emulsifier for said hydrophobic material, adding to the dispersion a melamine-formaldehyde precondensate, and heating the mixture in a acidic state to harden the melamine-formaldehyde precondensate to form the wall of the microcapsule.
Claim 2
Independent Claim
63 words
A method of producing micro-capsules containing a hydrophobic material comprising the steps of dispersing the hydrophobic material in an acidic aqueous solution of a styrene-maleic anhydride copolymer as dispersing agent or emulsifier for said hydrophobic material, adding to the dispersion a melamine-formaldehyde precondensate, and heating the mixture in a acidic state to harden the melamine-formaldehyde precondensate to form the wall of the microcapsule.
Claim 3
Dependent Claim
28 words
A method according to claim 1, wherein the amount of the styrene-maleic anhydride copolymer is 2 to 20 weight parts per 100 weight parts of the hydrophobic material.
Claim 4
Dependent Claim
28 words
A method according to claim 2 wherein the amount of the melamine-formaldehyde precondensate is 50 to 500 weight parts per 100 weight parts of the styrene-maleic anhydride copolymer.
Claim 5
Dependent Claim
28 words
A method according to claim 1, wherein the amount of the melamine-formaldehyde precondensate is 50 to 500 weight parts per 100 weight parts of the styrene-maleic anhydride copolymer.
Claim 6
Dependent Claim
23 words
A method according to claim 1, wherein the melamine-formaldehyde precondensate has been produced by reacting melamine with formaldehyde in the proportion of 1:2-1:3.
Claim 7
Dependent Claim
26 words
A method according to claim 1 wherein the melamine-formaldehyde precondensate has been produced by reacting melamine with formaldehyde in the proportion of 1: at least 1.5.
Claim 8
Dependent Claim
20 words
A method according to claim 6 wherein the melamine is reacted with formaldehyde in the ratio of 1:2 to 1:3.89.
Claim 9
Dependent Claim
13 words
Micro-capsules containing the hydrophobic material produced according to the method of claim 1.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1983-11-11 | 1984-05-12 | 1984-11-11 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1987-11-11 | 1988-05-12 | 1988-11-11 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1991-11-11 | 1992-05-12 | 1992-11-11 | $7700.00 | Window Closed / Lapsed |