US4219604A
Expired / Lapsed
US
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Method of forming microcapsules, microcapsular dispersion, and pressure sensitive recording sheet
Assignee: Fujifilm Holdings Corp
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Filing: 1978-12-18
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Granted: 1980-08-26
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Expires: 1998-12-18
Abstract
Abstract A method of forming microcapsules having high heat resistance and low permeability which comprises the step of forming wall films of urea-formaldehyde resin around individual droplets of a hydrophobic oily solution through the polymerization reaction of urea and formaldehyde in the presence of carboxylated polyvinyl alcohol.
Inventors
- 👤 Fujio Kakimi
- 👤 Yoshiyuki Hoshi
- 👤 Keiso Saeki
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-25 16:43
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; Y10T428/25; Y10T428/254
Claims Analysis
Total Claims: 12
Claim 1
Independent Claim
85 words
A method of forming microcapsules which comprises polymerizing a urea and formaldehyde resin capsule wall around individual droplets of a hydrophobic oily solution in the presence of carboxylated polyvinyl alcohol, wherein said carboxylated polyvinyl alcohol has a molecular weight of 1,000 to about 300,000, a saponification degree of 50% or more, a carboxy group content of 1 to about 40 mol %, and is present in the polymerization system in an amount of 0.5 to 10% by weight based on the weight of the system.
Claim 2
Independent Claim
85 words
A method of forming microcapsules which comprises polymerizing a urea and formaldehyde resin capsule wall around individual droplets of a hydrophobic oily solution in the presence of carboxylated polyvinyl alcohol, wherein said carboxylated polyvinyl alcohol has a molecular weight of 1,000 to about 300,000, a saponification degree of 50% or more, a carboxy group content of 1 to about 40 mol %, and is present in the polymerization system in an amount of 0.5 to 10% by weight based on the weight of the system.
Claim 3
Dependent Claim
16 words
The method of claim 1, wherein an ammonium acid salt is additionally present during said polymerization.
Claim 4
Dependent Claim
15 words
The method of claim 1, wherein a polyhydric phenol is additionally present during said polymerization.
Claim 5
Dependent Claim
33 words
The method of claim 1, which comprises polymerizing a resin capsule of urea, aldehyde and a compound having at least two amino groups in the molecule around droplets of a hydrophobic oily solution.
Claim 6
Dependent Claim
21 words
The method of claim 4, wherein said compound having at least two amino groups is guanidine, N-methyl urea, thiourea or melamine.
Claim 7
Independent Claim
113 words
A method of forming microcapsules which comprises: forming an aqueous solution of a carboxylated polyvinyl alcohol, wherein said carboxylated polyvinyl alcohol has a molecular weight of 1,000 to about 300,000, a saponification degree of 50% or more, a carboxy group content of 1 to about 40 mol %, and is present in the polymerization system in an amount of 0.5 to 10% by weight based on the weight of the system, emulsifying and dispersing a hydrophobic oily solution in said alcohol solution to form droplets of the hydrophobic oily solution, adding urea and formaldehyde to the system and copolymerizing the urea and formaldehyde to form a resin wall around the hydrophobic oil droplets.
Claim 8
Independent Claim
113 words
A method of forming microcapsules which comprises: forming an aqueous solution of a carboxylated polyvinyl alcohol, wherein said carboxylated polyvinyl alcohol has a molecular weight of 1,000 to about 300,000, a saponification degree of 50% or more, a carboxy group content of 1 to about 40 mol %, and is present in the polymerization system in an amount of 0.5 to 10% by weight based on the weight of the system, emulsifying and dispersing a hydrophobic oily solution in said alcohol solution to form droplets of the hydrophobic oily solution, adding urea and formaldehyde to the system and copolymerizing the urea and formaldehyde to form a resin wall around the hydrophobic oil droplets.
Claim 9
Dependent Claim
92 words
A pressure sensitive recording sheet comprising a support having coated thereon a layer of microcapsules prepared by polymerizing a urea and formaldehyde resin around individual droplets of a hydrophobic oily solution in the presence of carboxylated polyvinyl alcohol wherein said carboxylated polyvinyl alcohol has a molecular weight of 1,000 to about 300,000, a saponification degree of 50% or more, a carboxy group content of 1 to about 40 mol%, and is present in the polymerization system in an amount of 0.5 to 10% by weight based on the weight of the system.
Claim 10
Dependent Claim
92 words
A pressure sensitive recording sheet comprising a support having coated thereon a layer of microcapsules prepared by polymerizing a urea and formaldehyde resin around individual droplets of a hydrophobic oily solution in the presence of carboxylated polyvinyl alcohol wherein said carboxylated polyvinyl alcohol has a molecular weight of 1,000 to about 300,000, a saponification degree of 50% or more, a carboxy group content of 1 to about 40 mol%, and is present in the polymerization system in an amount of 0.5 to 10% by weight based on the weight of the system.
Claim 11
Dependent Claim
81 words
A microcapsule dispersion prepared by polymerizing a urea and formaldehyde resin wall around individual droplets of a hydrophobic oily solution in the presence of carboxylated polyvinyl alcohol, wherein said carboxylated polyvinyl alcohol has a molecular weight of 1,000 to about 300,000, a saponification degree of 50% or more, a carboxy group content of 1 to about 40 mol%, and is present in the polymerization system in an amount of 0.5 to 10% by weight based on the weight of the system.
Claim 12
Dependent Claim
81 words
A microcapsule dispersion prepared by polymerizing a urea and formaldehyde resin wall around individual droplets of a hydrophobic oily solution in the presence of carboxylated polyvinyl alcohol, wherein said carboxylated polyvinyl alcohol has a molecular weight of 1,000 to about 300,000, a saponification degree of 50% or more, a carboxy group content of 1 to about 40 mol%, and is present in the polymerization system in an amount of 0.5 to 10% by weight based on the weight of the system.
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) | 1983-08-26 | 1984-02-25 | 1984-08-26 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1987-08-26 | 1988-02-25 | 1988-08-26 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1991-08-26 | 1992-02-25 | 1992-08-26 | $7700.00 | Window Closed / Lapsed |