US4368237A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Process for producing magnetic recording device
Assignee: Fujifilm Holdings Corp
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Filing: 1979-05-14
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Granted: 1983-01-11
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Expires: 1999-05-14
Abstract
Abstract A magnetic recording material having superior abrasion resistance and thermal stability is produced by coating a magnetic coating composition consisting essentially of aqueous emulsions of at least two resin binders capable of reacting with each other upon mixing, and being present therein in the separated state, and a ferromagnetic powder on a non-magnetic support, drying the coating, and curing the resulting magnetic recording layer where drying is insufficient to effect curing. Hazards ascribable to the use of organic solvents in conventional techniques can be obviated by this invention.
Inventors
- 👤 Yasuyuki Yamada
- 👤 Tatsuji Kitamoto
- 👤 Goro Akashi
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-27 22:51
CPC Classifications
G; G11; G11B; G11B5/00; G11B5/62; G11B5/68; G11B5/70; G11B5/702; G11B5/7021; G11B5/7022; Y; Y10; Y10S; Y10S428/00; Y10S428/90; Y10T; Y10T428/00; Y10T428/31504; Y10T428/31511; Y10T428/31551; Y10T428/31609; Y10T428/31725; Y10T428/31855; Y10T428/31935
Claims Analysis
Total Claims: 22
Claim 1
Independent Claim
186 words
A process for producing a magnetic recording material, which comprises separately emulsifying in water at least two components capable of reacting with each other upon mixing, to form at least two separate emulsions, combining the resulting emulsions while maintaining said at least two components in the separated state, coating a magnetic coating composition consisting essentially of a ferromagnetic fine powder, a binder consisting of said at least two components in said combined emulsion, and a coating liquid on a non-magnetic support, drying the coating to form a magnetic recording layer, and curing the resulting magnetic recording layer if drying is insufficient to effect curing thereof, wherein said at least two components contain reactive groups selected from the group consisting of hydroxyl (--OH), carboxyl (--COOH), epoxy ##STR8## carbonyl (C═O), amino (--NH 2 ), isocyanate (--NCO), or thiocyanate (--NCS), and wherein the molar ratio of reactive groups to react with one another is about 35/65. to 65/35, the amount of binder in the coating composition is 10-70% by weight, as solids content, and is 17-100 parts by weight per 100 parts by weight of the ferromagnetic fine powder.
Claim 2
Dependent Claim
186 words
A process for producing a magnetic recording material, which comprises separately emulsifying in water at least two components capable of reacting with each other upon mixing, to form at least two separate emulsions, combining the resulting emulsions while maintaining said at least two components in the separated state, coating a magnetic coating composition consisting essentially of a ferromagnetic fine powder, a binder consisting of said at least two components in said combined emulsion, and a coating liquid on a non-magnetic support, drying the coating to form a magnetic recording layer, and curing the resulting magnetic recording layer if drying is insufficient to effect curing thereof, wherein said at least two components contain reactive groups selected from the group consisting of hydroxyl (--OH), carboxyl (--COOH), epoxy ##STR8## carbonyl (C═O), amino (--NH 2 ), isocyanate (--NCO), or thiocyanate (--NCS), and wherein the molar ratio of reactive groups to react with one another is about 35/65. to 65/35, the amount of binder in the coating composition is 10-70% by weight, as solids content, and is 17-100 parts by weight per 100 parts by weight of the ferromagnetic fine powder.
Claim 3
Dependent Claim
61 words
The process of claim 1 wherein said binder components are selected from the group consisting of thermoplastic resins having a softening point of not more than 150° C., an average molecular weight of 10,000 to 200,000 and a degree of polymerization of about 200 to 2,000, and thermosetting resins and reactive resins having a molecular weight of not more than 200,000.
Claim 4
Dependent Claim
28 words
The process of claim 2 wherein said thermoplastic resin is present in an amount of 0 to about 15 weight % of the total amount of resin binder.
Claim 5
Dependent Claim
31 words
The process of claim 1 wherein said at least two components containing reactive groups are polymers selected from the group consisting of acrylic resins, epoxy resins, polyamide resins, and blocked polyisocyanates.
Claim 6
Dependent Claim
32 words
The process of claim 1 wherein the amount of the binder in the coating composition is 20 to 70 parts by weight per 100 parts by weight of the ferromagnetic fine powder.
Claim 7
Dependent Claim
32 words
The process of claim 1 wherein the amount of the binder in the coating composition is 25 to 40 parts by weight per 100 parts by weight of the ferromagnetic fine powder.
Claim 8
Dependent Claim
22 words
The process of claim 1 wherein the coated magnetic recording layer is subjected to a treatment for orienting the ferromagnetic powder therein.
Claim 9
Dependent Claim
21 words
The process of claim 1 wherein the drying is carried out at 50° to 100° C. for 2 to 10 minutes.
Claim 10
Dependent Claim
23 words
The process of claim 1 wherein curing is carried out at 30° to 180° C. for 10 seconds to 120 hours after drying.
Claim 11
Dependent Claim
22 words
The process of claim 1 wherein the magnetic recording layer has a dry thickness of from about 1 to about 20 um.
Claim 12
Dependent Claim
11 words
A magnetic recording material produced by the process of claim 1.
Claim 13
Dependent Claim
24 words
The process of claim 1 wherein said components capable of reacting with each other each contain from two to six of said reactive groups.
Claim 14
Dependent Claim
182 words
A process for producing a magnetic recording material, which comprises separately emulsifying in water at least two components capable of reacting with each other upon mixing, to form at least two separate emulsions, combining the resulting emulsions while maintaining said at least two components in the separated state, coating a magnetic coating composition consisting essentially of a ferromagnetic fine powder, a binder consisting of said at least two components in said combined emulsion, and a coating liquid on a non-magnetic support, drying the coating to form a magnetic recording layer, and curing the resulting magnetic recording layer if drying is insufficient to effect curing thereof, wherein said at least two components contain reactive groups selected from the group consisting of hydroxyl (--OH), carboxyl (--COOH), epoxy ##STR9## amino (--NH 2 ), or isocyanate (--NCO), and wherein the molar ratio of reactive groups to react with one another is about 36/65 to 65/35, the amount of binder in the coating composition to 10-70% by weight, as solids content, and is 17-100 parts by weight per 100 parts by weight of the ferromagnetic fine powder.
Claim 15
Dependent Claim
182 words
A process for producing a magnetic recording material, which comprises separately emulsifying in water at least two components capable of reacting with each other upon mixing, to form at least two separate emulsions, combining the resulting emulsions while maintaining said at least two components in the separated state, coating a magnetic coating composition consisting essentially of a ferromagnetic fine powder, a binder consisting of said at least two components in said combined emulsion, and a coating liquid on a non-magnetic support, drying the coating to form a magnetic recording layer, and curing the resulting magnetic recording layer if drying is insufficient to effect curing thereof, wherein said at least two components contain reactive groups selected from the group consisting of hydroxyl (--OH), carboxyl (--COOH), epoxy ##STR9## amino (--NH 2 ), or isocyanate (--NCO), and wherein the molar ratio of reactive groups to react with one another is about 36/65 to 65/35, the amount of binder in the coating composition to 10-70% by weight, as solids content, and is 17-100 parts by weight per 100 parts by weight of the ferromagnetic fine powder.
Claim 16
Dependent Claim
47 words
The process of claim 13 wherein the at least two components are selected to provide one of the following combinations of reactive groups: epoxy and --NH 2 ; --COOH and --NH 2 ; --COOH and --NCO; --OH, --NCO and --OH; epoxy and --NCO; and --OH and --NCO.
Claim 17
Dependent Claim
15 words
The process of claim 13 wherein the reactive groups are epoxy and --NH 2 .
Claim 18
Dependent Claim
15 words
The process of claim 13 wherein the reactive groups are --COOH and --NH 2 .
Claim 19
Dependent Claim
13 words
The process of claim 13 wherein the reactive groups are --COOH and --NCO.
Claim 20
Dependent Claim
14 words
The process of claim 13 wherein the reactive groups are --OH, --NCO and --OH.
Claim 21
Dependent Claim
13 words
The process of claim 13 wherein the reactive groups are epoxy and --NCO.
Claim 22
Dependent Claim
13 words
The process of claim 13 wherein the reactive groups are --OH and --NCO.
References Cited (Backward Citations)
US4068040A
Cited
US3967045A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1986-01-10 | 1986-07-12 | 1987-01-11 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1990-01-10 | 1990-07-12 | 1991-01-11 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1994-01-10 | 1994-07-12 | 1995-01-11 | $7700.00 | Window Closed / Lapsed |