US4251386A
Expired / Lapsed
US
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Method for preparing microcapsules
Assignee: Fujifilm Holdings Corp
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Filing: 1978-07-20
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Granted: 1981-02-17
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Expires: 1998-07-20
Abstract
Abstract A method for preparing microcapsules comprising polymerizing urea and formaldehyde in the presence of an anionic polyelectrolyte and an ammonium salt of an acid and forming a wall membrane of a urea/formaldehyde resin around droplets of a hydrophobic oily liquid.
Inventors
- 👤 Keiso Saeki
- 👤 Hiroharu Matsukawa
- 👤 Masato Satomura
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-25 18:30
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: 19
Claim 1
Independent Claim
90 words
In a method for preparing microcapsules comprising polymerizing urea and formaldehyde in water in the presence of 0.75 to 10% by weight of an anionic polyelectrolyte and forming a wall membrane of a urea/formaldehyde resin around droplets of a hydrophobic oily liquid, the improvement which comprises the presence of about 1% by weight or more, based on the weight of the urea, of an ammonium salt of an acid, whereby microcapsules having high heat resistance, high strength, low permeability and which are also free from microcapsule slurry coloration are obtained.
Claim 2
Dependent Claim
90 words
In a method for preparing microcapsules comprising polymerizing urea and formaldehyde in water in the presence of 0.75 to 10% by weight of an anionic polyelectrolyte and forming a wall membrane of a urea/formaldehyde resin around droplets of a hydrophobic oily liquid, the improvement which comprises the presence of about 1% by weight or more, based on the weight of the urea, of an ammonium salt of an acid, whereby microcapsules having high heat resistance, high strength, low permeability and which are also free from microcapsule slurry coloration are obtained.
Claim 3
Dependent Claim
27 words
The method of claim 1, wherein said anionic polyelectrolyte is a natural or synthetic anionic polyelectrolyte containing a --COO - group or a --SO 3 - group.
Claim 4
Dependent Claim
35 words
The method of claim 2, wherein said anionic polyelectrolyte is a copolymer of maleic anhydride, a polymer or copolymer of acrylic acid or methacrylic acid or a polymer or copolymer of vinyl benzene sulfonic acid.
Claim 5
Dependent Claim
30 words
The method of claim 3, wherein said acid is chloric acid, chromic acid, nitric acid, permanganic acid, selenic acid, sulfuric acid, hydrochloric acid, perchloric acid, hydrobromic acid or hydroiodic acid.
Claim 6
Dependent Claim
25 words
The method of claim 3, wherein said acid is trifluoroacetic acid, trichloroacetic acid, benzene sulfonic acid, naphthalene sulfonic acid, p-toluene sulfonic acid or maleic acid.
Claim 7
Dependent Claim
104 words
The method of claim 3, wherein said maleic anhydride copolymer contains about 10 to about 60 mol% of maleic anhydride and has a molecular weight of about 5,000 to about 2,000,000; said polymer or copolymer of acrylic acid or methacrylic acid contains about 5 to about 100 mol% of acrylic acid or methacrylic acid, or the salt thereof, and has a molecular weight of about 20,000 to about 1,000,000; and said polymer or copolymer of vinyl benzene sulfonic acid contains about 5 to 100 mol% of vinyl benzene sulfonic acid or the salt thereof and has a molecular weight of about 5,000 to 2,000,000.
Claim 8
Dependent Claim
30 words
The method of claim 6, wherein said acid is chloric acid, chromic acid, nitric acid, permanganic acid, selenic acid, sulfuric acid, hydrochloric acid, perchloric acid, hydrobromic acid or hydroiodic acid.
Claim 9
Dependent Claim
25 words
The method of claim 6, wherein said acid is trifluoroacetic acid, trichloroacetic acid, benzene sulfonic acid, naphthalene sulfonic acid, p-toluene sulfonic acid or maleic acid.
Claim 10
Dependent Claim
25 words
The method of claim 1, wherein said hydrophobic oily liquid is a natural mineral oil, an animal oil, a vegetable oil or a snythetic oil.
Claim 11
Dependent Claim
43 words
The method of claim 1, wherein said hydrophobic oily liquid has dissolved therein at least one of an agrichemical, a medicine, a perfume, an adhesive, a liquid crystal, a food, a detergent, a dye, a catalyst, a fine chemical or a corrosion inhibitor.
Claim 12
Dependent Claim
20 words
The method of claim 1, wherein said ammonium salt of an acid is an ammonium salt of an inorganic acid.
Claim 13
Dependent Claim
31 words
The method of claim 11, wherein said inorganic acid is chloric acid, chromic acid, nitric acid, permanganic acid, selenic acid, sulfuric acid, hydrochloric acid, perchloric acid, hydrobromic acid or hydroiodic acid.
Claim 14
Dependent Claim
17 words
The method of claim 1, wherein the polymerizing is at a pH of about 7.0 or less.
Claim 15
Dependent Claim
19 words
The method of claim 1, wherein the polymerizing is at a temperature of about 10° to about 95° C.
Claim 16
Dependent Claim
21 words
The method of claim 1, wherein the molar ratio of the formaldehyde to the urea is about 0.6:1 to about 5:1.
Claim 17
Dependent Claim
20 words
The method of claim 1, wherein said ammonium salt of an acid is an ammonium salt of an organic acid.
Claim 18
Dependent Claim
26 words
The method of claim 16, wherein said organic acid is trifluoroacetic acid, trichloroacetic acid, benzene sulfonic acid, naphthalene sulfonic acid, p-toluene sulfonic acid or maleic acid.
Claim 19
Dependent Claim
15 words
The method of claim 1, wherein said hydrophobic oily liquid is a color former compound.
References Cited (Backward Citations)
US3707514A
Cited
US4001140A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1984-02-17 | 1984-08-18 | 1985-02-17 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1988-02-17 | 1988-08-18 | 1989-02-17 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1992-02-17 | 1992-08-18 | 1993-02-17 | $7700.00 | Window Closed / Lapsed |