Patent US4409156A successfully refreshed from Google Patents.
US4409156A
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Process for producing microcapsules
Assignee: Fujifilm Holdings Corp
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Filing: 1980-10-02
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Granted: 1983-10-11
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Expires: 2000-10-02
Abstract
Abstract A process for producing microcapsules comprising forming capsule membranes of a polymer of melamine and formaldehyde in the presence of a styrene-sulfonic acid polymer.
Inventors
- 👤 Yoshiyuki Hoshi
- 👤 Takayuki Hayashi
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-28 13:21
CPC Classifications
B; B41; B41M; B41M5/00; B41M5/124; B41M5/165; 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: 11
Claim 1
Independent Claim
81 words
A process for producing microcapsules consisting essentially of the steps of: (a) preparing a solution of melamine and formaldehyde prepolymer, (b) preparing a solution of a styrene-sulfonic acid polymer, (c) dispersing a core material in said styrene-sulfonic acid polymer solution, (d) mixing said melamine-formaldehyde prepolymer solution and said styrene-sulfonic acid polymer solution, (e) heating said solutions to form microcapsules having melamine-formaldehyde members wherein the ratio of styrene-sulfonic acid polymer to melamine in the capsule production system is about 0.2 to 20.
Claim 2
Dependent Claim
81 words
A process for producing microcapsules consisting essentially of the steps of: (a) preparing a solution of melamine and formaldehyde prepolymer, (b) preparing a solution of a styrene-sulfonic acid polymer, (c) dispersing a core material in said styrene-sulfonic acid polymer solution, (d) mixing said melamine-formaldehyde prepolymer solution and said styrene-sulfonic acid polymer solution, (e) heating said solutions to form microcapsules having melamine-formaldehyde members wherein the ratio of styrene-sulfonic acid polymer to melamine in the capsule production system is about 0.2 to 20.
Claim 3
Dependent Claim
18 words
The process of claim 1 which additonally comprises the step: (f) of removing residual formaldehyde after capsule formation.
Claim 4
Dependent Claim
25 words
The process of claim 2 wherein said residual formaldehyde is removed by adding urea and reacting at a pH less than or equal to 4.
Claim 5
Dependent Claim
33 words
The process of claim 1 wherein said melamine-formaldehyde prepolymer is prepared by heating a solution of melamine and formaldehyde at a pH of 6 to 10 at temperatures of 40° C. or higher.
Claim 6
Dependent Claim
29 words
The process of claim 1 wherein said styrene-sulfonic acid polymer is present in an amount of 1 to 20 parts by weight per 100 parts by weight core material.
Claim 7
Dependent Claim
17 words
The process of claim 1 wherein the pH of said emulsion system is about 1 to 8.
Claim 8
Dependent Claim
14 words
The process of claim 1 wherein said emulsion system additionally contains a polyvalent isocyanate.
Claim 9
Dependent Claim
13 words
The process of claim 1 wherein said styrene-sulfonic acid polymer is polystyrene-sulfonic acid.
Claim 10
Dependent Claim
16 words
The process of claim 1 wherein said styrene-sulfonic acid polymer is a copolymer of styrene-sulfonic acid.
Claim 11
Dependent Claim
25 words
The process of claim 9 wherein said copolymer is a copolymer of acrylic acid, maleic acid anhydride, ethylene, or an ethylene derivative and styrene-sulfonic acid.
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) | 1986-10-10 | 1987-04-11 | 1987-10-11 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1990-10-10 | 1991-04-11 | 1991-10-11 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1994-10-10 | 1995-04-11 | 1995-10-11 | $7700.00 | Window Closed / Lapsed |