Patent US4753759A successfully refreshed from Google Patents.
US4753759A
Expired / Lapsed
US
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Microcapsule manufacture
Assignee: Sakura Color Products Corp
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Filing: 1986-08-01
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Granted: 1988-06-28
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Expires: 2006-08-01
Abstract
Abstract A process for manufacturing microcapsules by dissolving or dispersing microcapsule contents in an aqueous solution of acrylic acid-methacrylic acid copolymer and/or acrylic acid-itaconic acid copolymer, then polymerizing urea and/or melamine and formaldehyde in the solution or dispersion adjusted to pH 2.5˜6.0, and forming film of urea-formaldehyde copolymer, melamine-formaldehyde copolymer, or urea-melamine-formaldehyde copolymer around capusle contents. Microcapsules manufactured by this process are useful for colors for carbonless paper or thermo-changeable colors.
Inventors
- 👤 Hidetoshi Fukuo
- 👤 Tomio Onoguchi
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-26 08:46
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: 14
Claim 1
Independent Claim
85 words
A microencapsulating method comprising emulsifying a filling including a hydrophobic substantially involatile organic compound, an electron donor organic coloring compound and a phenol hydroxide compound in a 3% to 20% by weight aqueous solution of acrylic acid-methacrylic acid copolymer consisting of acrylic acid and methacrylic acid monomers and/or acrylic acid-itaconic acid-copolymer and polymerizing in said emulsion urea and/or melamine with formaldehyde at a pH between 2.5 and 6.0 to form a capsule film of urea-formaldehyde copolymer or melamine-formaldehyde copolymer or urea-melamine-formaldehyde copolymer microencapsulating said filling.
Claim 2
Dependent Claim
85 words
A microencapsulating method comprising emulsifying a filling including a hydrophobic substantially involatile organic compound, an electron donor organic coloring compound and a phenol hydroxide compound in a 3% to 20% by weight aqueous solution of acrylic acid-methacrylic acid copolymer consisting of acrylic acid and methacrylic acid monomers and/or acrylic acid-itaconic acid-copolymer and polymerizing in said emulsion urea and/or melamine with formaldehyde at a pH between 2.5 and 6.0 to form a capsule film of urea-formaldehyde copolymer or melamine-formaldehyde copolymer or urea-melamine-formaldehyde copolymer microencapsulating said filling.
Claim 3
Dependent Claim
12 words
The method of claim 1 wherein said filling includes a leuko dyestuff.
Claim 4
Dependent Claim
32 words
The method of claim 1 wherein the mole ratio of acrylic acid to methacrylic acid and of acrylic acid to itaconic acid in the respective copolymers thereof is between 1:0.5 and 1:3.
Claim 5
Dependent Claim
27 words
The method of claim 1 wherein the average molecular weights of said acrylic acid-methacrylic acid copolymer and acrylic acid-itaconic acid copolymer respectively is between 10,000 and 500,000.
Claim 6
Dependent Claim
16 words
The method of claim 1 wherein an encapsulating accelerating agent is added to said aqueous solution.
Claim 7
Dependent Claim
105 words
A micro-capsulization method characterized in that in a 3% to 20% by weight aqueous solution of an acrylic acid-methacrylic acid copolymer consisting of acrylic acid and methacrylic acid monomers and/or acrylic acid-itaconic acid copolymer as a system modifier is emulsified a solution or dispersion of a filling including a fatty acid with a carbon number of at least 8, an electron donor organic coloring compound and a compound having phenolic hydroxide group/s, urea and/or melamine and formaldehyde are added and polymerization effected at a pH of 2.5-6.0 whereby particles of said filling are microencapsulated in a film of urea-formaldehyde copolymer, melamine-formaldehyde copolymer or urea-melamine-formaldehyde copolymer.
Claim 8
Dependent Claim
105 words
A micro-capsulization method characterized in that in a 3% to 20% by weight aqueous solution of an acrylic acid-methacrylic acid copolymer consisting of acrylic acid and methacrylic acid monomers and/or acrylic acid-itaconic acid copolymer as a system modifier is emulsified a solution or dispersion of a filling including a fatty acid with a carbon number of at least 8, an electron donor organic coloring compound and a compound having phenolic hydroxide group/s, urea and/or melamine and formaldehyde are added and polymerization effected at a pH of 2.5-6.0 whereby particles of said filling are microencapsulated in a film of urea-formaldehyde copolymer, melamine-formaldehyde copolymer or urea-melamine-formaldehyde copolymer.
Claim 9
Dependent Claim
27 words
The method of claim 6 wherein said filling is prepared by dissolving or dispersing said organic coloring compound and said phenolic hydroxide compound in said fatty acid.
Claim 10
Dependent Claim
24 words
The process for manufacturing of claim 6 wherein the system modifier is acrylic acid-methacrylic acid copolymer consisting of acrylic acid and methacrylic acid monomers.
Claim 11
Dependent Claim
24 words
The process for manufacturing of claim 6 wherein the system modifier is acrylic acid-itaconic acid copolymer consisting of acrylic acid and itaconic acid monomers.
Claim 12
Dependent Claim
19 words
The process for manufacturing of any of claims 8, 9 or 6 wherein the capsule film is urea-formaldehyde copolymer.
Claim 13
Dependent Claim
19 words
The process for manufacturing of any of claims 8, 9 or 6 wherein the capsule film is melamine-formaldehyde copolymer.
Claim 14
Dependent Claim
19 words
The process for manufacturing of any of claims 8, 9 or 6 wherein the capsule film is urea-melamine-formaldehyde copolymer.
References Cited (Backward Citations)
US4328119A
Cited
US4574110A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1991-06-28 | 1991-12-28 | 1992-06-28 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1995-06-28 | 1995-12-28 | 1996-06-28 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1999-06-28 | 1999-12-28 | 2000-06-28 | $7700.00 | Window Closed / Lapsed |