US4753968A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Process for preparing microcapsules
Assignee: New Oji Paper Co Ltd
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Filing: 1986-07-16
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Granted: 1988-06-28
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Expires: 2006-07-16
Abstract
Abstract In a microencapsulation process which comprises polycondensating a hydrophilic melamine-formaldehyde resin type precondensate in water or in a hydrophilic medium containing an emulsifier to form capsule wall film around a hydrophobic core material to obtain microcapsules, the process which is characterized in that the emulsifier is a copolymer of (1) an unsaturated monobasic acid monomer of at least 80 mole %, (2) a hydrophobic monomer and (3) a hydrophilic monomer other than a carboxylic acid.
Inventors
- 👤 Shunsuke Shioi
- 👤 Kazuyuki Shinmitsu
- 👤 Masanao Tajiri
- 👤 Makoto Miyake
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-02 07:21
CPC Classifications
B; B01; B01J; B01J13/00; B01J13/02; B01J13/06; B01J13/14; B01J13/18
Claims Analysis
Total Claims: 11
Claim 1
Independent Claim
119 words
In a microencapsulation process which comprises polycondensating a hydrophilic melamine-formaldehyde resin type precondensate in water or in a hydrophilic medium containing an emulsifier to form capsule wall film around a hydrophobic core material to obtain microcapsules, the improvement comprising the emulsifier is a copolymer of (1) 85-97 mole % of an unsaturated monobasic acid monomer selected from the group consisting of acrylic acid and methacrylic acid; (2) 2-10 mole % of a hydrophobic monomer selected from the group consisting of C 1 ˜8 alkyl (meth)acrylates; and (3) 1-10 mole % of a hydrophilic monomer other than a carboxylic acid which is at least one compound selected from the group consisting of sulfonic acids, amides, amines and organic phosphonic acids.
Claim 2
Dependent Claim
119 words
In a microencapsulation process which comprises polycondensating a hydrophilic melamine-formaldehyde resin type precondensate in water or in a hydrophilic medium containing an emulsifier to form capsule wall film around a hydrophobic core material to obtain microcapsules, the improvement comprising the emulsifier is a copolymer of (1) 85-97 mole % of an unsaturated monobasic acid monomer selected from the group consisting of acrylic acid and methacrylic acid; (2) 2-10 mole % of a hydrophobic monomer selected from the group consisting of C 1 ˜8 alkyl (meth)acrylates; and (3) 1-10 mole % of a hydrophilic monomer other than a carboxylic acid which is at least one compound selected from the group consisting of sulfonic acids, amides, amines and organic phosphonic acids.
Claim 3
Dependent Claim
17 words
A process as defined in claim 1 wherein the hydrophobic monomer is C 1 ˜4 alkyl (meth)acrylate.
Claim 4
Dependent Claim
20 words
A process as defined in claim 1 wherein the hydrophilic monomer other than a carboxylic acid is acrylamide or methacrylamide.
Claim 5
Dependent Claim
22 words
A process as defined in claim 1 wherein the hydrophilic monomer other than a carboxylic acid is dimethylaminoethyl acrylate or dimethylaminoethyl methacrylate.
Claim 6
Dependent Claim
19 words
A process as defined in claim 1 wherein the emulsifier has a molecular weight of about 10,000 to 1,000,000.
Claim 7
Dependent Claim
28 words
A process as defined in claim 1 wherein the emulsifier is contained in water or in a hydrophilic medium in an amount of 0.1 to 20% by weight.
Claim 8
Dependent Claim
33 words
A process as defined in claim 1 wherein the hydrophilic melamine-formaldehyde resin type precondensate is melamine-formaldehyde resin precondensate, methylated product thereof, modified products with other amines, phenols, aldehydes or anionic-, cationic- or nonionic-modifier.
Claim 9
Dependent Claim
40 words
A process as defined in claim 1 wherein the hydrophilic melamine-formaldehyde resin type precondensate is used in an amount of 2 to 40 parts by weight in terms of melamine per 100 parts by weight of the hydrophobic core material.
Claim 10
Dependent Claim
23 words
A process as defined in claim 1 wherein the precondensate is added to the system at a temperature of 65° C. or higher.
Claim 11
Dependent Claim
37 words
A process as defined in claim 1 wherein the microcapsules are prepared under a condition of maintaining the reaction system at a pH of up to 5.0 and at least 60° C. for more than 2 hours.
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) | 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 |