US4356109A
Expired / Lapsed
US
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Method for preparing microcapsules
Assignee: Fujifilm Holdings Corp
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Filing: 1980-02-07
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Granted: 1982-10-26
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Expires: 2000-02-07
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
2026-10-26 06:57
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: 16
Claim 1
Independent Claim
87 words
A method for preparing microcapsules comprising polymerizing urea and formaldehyde in an aqueous solution 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, wherein the amount of polyelectrolyte is about 0.5 to 15% by weight based on the weight of the aqueous solution and the ammonium salt is used in an amount of about 1 to 200% by weight, based on the weight of the urea.
Claim 2
Independent Claim
87 words
A method for preparing microcapsules comprising polymerizing urea and formaldehyde in an aqueous solution 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, wherein the amount of polyelectrolyte is about 0.5 to 15% by weight based on the weight of the aqueous solution and the ammonium salt is used in an amount of about 1 to 200% by weight, based on the weight of the urea.
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
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 6
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 synthetic oil.
Claim 7
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 8
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 9
Dependent Claim
45 words
The method of claim 1, wherein the acid is chloric acid, chromic acid, nitric acid, permanganic acid, selenic acid, sulfuric acid, hydrochloric acid, perchloric acid, hydrobromic acid, hydroiodic acid, trifluoroacetic acid, trichloroacetic acid, benzene sulfonic acid, naphthalene sulfonic acid, p-toluene sulfonic acid or maleic acid.
Claim 10
Dependent Claim
29 words
The method of claim 1, wherein the amount of the ammonium salt of the acid is about 1% by weight or more based on the weight of the urea.
Claim 11
Dependent Claim
17 words
The method of claim 1, wherein the polymerizing is at a pH of about 7.0 or less.
Claim 12
Dependent Claim
19 words
The method of claim 1, wherein the polymerizing is at a temperature of about 10° to about 95° C.
Claim 13
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 14
Dependent Claim
46 words
The method of claim 1, wherein the anionic polyelectrolyte is used in an amount of 2 to 10% by weight of the aqueous solution and the ammonium salt is used in an amount of 5 to 150% by weight based on the weight of the urea.
Claim 15
Dependent Claim
27 words
The method of claim 13, wherein the ammonium salt is used in an amount of 10 to 100% by weight based on the weight of the urea.
Claim 16
Dependent Claim
20 words
The method of claim 1, wherein said ammonium salt of an acid is an ammonium salt of an organic acid.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
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| 3.5 Years (Year 4) | 1985-10-25 | 1986-04-26 | 1986-10-26 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1989-10-25 | 1990-04-26 | 1990-10-26 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1993-10-25 | 1994-04-26 | 1994-10-26 | $7700.00 | Window Closed / Lapsed |