US4637959A
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Magnetic recording medium
Assignee: Sony Corp
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Filing: 1984-10-22
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Granted: 1987-01-20
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Expires: 2004-10-22
Abstract
Abstract A magnetic recording medium comprised of a non-magnetic substrate and a magnetic layer formed on one surface of the substrate and consisting essentially of a binder and magnetic powders. As the binder, a thermoplastic polyurethane-urea resin is employed, in which hydrophilic polar groups are introduced. The thermoplastic polyurethane-urea resin contains urethane and urea bonds in the molecule thereof and may be synthesized from a long-chain diol with a molecular weight of about 500 to 5000, a short-chain diol with a molecular weight of about 50 to 500, an organic diisocyanate and an organic diamine. Examples of the thus introduced hydrophilic polar groups are: <IMAGE>
Inventors
- 👤 Yoshinobu Ninomiya
- 👤 Masashi Somezawa
- 👤 Kiyokazu Oiyama
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-03 20:50
CPC Classifications
C; C08; C08G; C08G18/00; C08G18/06; C08G18/08; C08G18/0804; C08G18/0819; C08G18/28; C08G18/30; C08G18/38; C08G18/3878; C08G18/3889; G; G11; G11B; G11B5/00; G11B5/62; G11B5/68; G11B5/70; G11B5/702; G11B5/7021; Y; Y10; Y10S; Y10S428/00; Y10S428/90; Y10T; Y10T428/00; Y10T428/31504; Y10T428/31551; Y10T428/31609
Claims Analysis
Total Claims: 54
Claim 1
Independent Claim
107 words
A magnetic recording medium comprising a non-magnetic substrate and a magnetic layer formed thereon composed mainly of magnetic powder and a binder, said binder containing a thermoplastic polyurethane-urea resin hardened by a polyisocyanate and having at least one hydrophilic polar group selected from the group consisting of the groups represented by general formulas: ##STR19## wherein M is hydrogen or alkali metal and M' is hydrogen, alkali metal or hydrocarbon group, the total concentration of urea groups and urethane groups in said resin being between 1.8 and 3 m mol/g, and the concentration ration between urea groups and ureathane groups in said resin being between 0.3 and 1.6.
Claim 2
Dependent Claim
107 words
A magnetic recording medium comprising a non-magnetic substrate and a magnetic layer formed thereon composed mainly of magnetic powder and a binder, said binder containing a thermoplastic polyurethane-urea resin hardened by a polyisocyanate and having at least one hydrophilic polar group selected from the group consisting of the groups represented by general formulas: ##STR19## wherein M is hydrogen or alkali metal and M' is hydrogen, alkali metal or hydrocarbon group, the total concentration of urea groups and urethane groups in said resin being between 1.8 and 3 m mol/g, and the concentration ration between urea groups and ureathane groups in said resin being between 0.3 and 1.6.
Claim 3
Dependent Claim
100 words
The magnetic recording medium according to claim 1, wherein the thermoplastic polyurethane-urea resin is obtained by the polyaddition reaction of (A) a long-chain diol having a molecular weight in a range of about 500 to 5000; (B) a short-chain diol having a molecular weight in a range of about 50 to 500; (C) an organic diamine; (D) an organic diisocyanate; and (E) a compound having at least one hydrophilic polar group selected from the group consisting of the groups represented by general formulas: ##STR20## wherein M is hydrogen or alkali metal and M' is hydrogen, alkali metal or hydrocarbon group.
Claim 4
Dependent Claim
20 words
The magnetic recording medium according to claim 1, wherein the thermoplastic polyurethane-urea resin is cured with a polyisocyanate curing agent.
Claim 5
Dependent Claim
25 words
The magnetic recording medium according to claim 1, wherein the concentration of hydrophilic polar group in said resin is between 0.01 and 1.0 m mol/g.
Claim 6
Dependent Claim
25 words
The magnetic recording medium according to claim 4, wherein the concentration of hydrophilic polar group in said resin is between 0.1 and 0.5 m mol/g.
Claim 7
Dependent Claim
21 words
The magnetic recording medium according to claim 1, wherein the number-average molecular weight of said resin is between 10000 and 100000.
Claim 8
Dependent Claim
21 words
The magnetic recording medium according to claim 6, wherein the number-average molecular weight of said resin is between 10000 and 60000.
Claim 9
Dependent Claim
21 words
The magnetic recording medium according to claim 1, wherein the softening point of said resin is not less than 80° C.
Claim 10
Dependent Claim
21 words
The magnetic recording medium according to claim 8, wherein the softening point of said resin is not less than 100° C.
Claim 11
Dependent Claim
22 words
The magnetic recording medium according to claim 1, wherein the glass transition point of said resin is not more than 0° C.
Claim 12
Dependent Claim
22 words
The magnetic recording medium according to claim 10, wherein the glass transition point of said resin is not more than -10° C.
Claim 13
Dependent Claim
25 words
The magnetic recording medium according to claim 2, wherein the weight ratio of the short-chain diol to the long-chain diol is not more than 3.
Claim 14
Dependent Claim
24 words
The magnetic recording medium according to claim 2, wherein the long-chain diol is a polyester diol, a polyether diol or a polyether ester diol.
Claim 15
Dependent Claim
38 words
The magnetic recording medium according to claim 13, wherein the polyester diol is obtained by the reaction of an aliphatic dicarboxylic acid, an aromatic dicarboxylic acid or a lower alcohol ester of the dicarboxylic acid with a glycol.
Claim 16
Dependent Claim
23 words
The magnetic recording medium according to claim 14, wherein the aliphatic dicarboxylic acid is succinic acid, adipic acid, sebacic acid or azelaic acid.
Claim 17
Dependent Claim
19 words
The magnetic recording medium according to claim 14, wherein the aromatic dicarboxylic acid is terephthalic acid or isophthalic acid.
Claim 18
Dependent Claim
22 words
The magnetic recording medium according to claim 14, wherein the lower alcohol ester of dicarboxylic acid is a methyl or ethyl ester.
Claim 19
Dependent Claim
35 words
The magnetic recording medium according to claim 14, wherein the glycol is ethylene glycol, 1,3-propylene glycol, 1,4-butylene glycol, 1,6-hexane glycol, diethylene glycol, neopentyl glycol or an ethylene oxide or propylene oxide adduct of bisphenol A.
Claim 20
Dependent Claim
24 words
The magnetic recording medium according to claim 2, wherein the long-chain diol is a polyester diol, a polyether diol or a polyether ester glycol.
Claim 21
Dependent Claim
38 words
The magnetic recording medium according to claim 19, wherein the polyester diol is obtained by the reaction of an aliphatic dicarboxylic acid, an aromatic dicarboxylic acid or a lower alcohol ester of the dicarboxylic acid with a glycol.
Claim 22
Dependent Claim
23 words
The magnetic recording medium according to claim 20, wherein the aliphatic dicarboxylic acid is succinic acid, adipic acid, sebacic acid or azelaic acid.
Claim 23
Dependent Claim
19 words
The magnetic recording medium according to claim 20, wherein the aromatic dicarboxylic acid is terephthalic acid or isophthalic acid.
Claim 24
Dependent Claim
19 words
The magnetic recording medium according to claim 20, wherein the lower alcohol ester is a methyl or ethyl ester.
Claim 25
Dependent Claim
35 words
The magnetic recording medium according to claim 20, wherein the glycol is ethylene glycol, 1,3-propylene glycol, 1,4-butylene glycol, 1,6-hexane glycol, diethylene glycol, neopentyl glycol or an ethylene oxide or propylene oxide adduct of bisphenol A.
Claim 26
Dependent Claim
21 words
The magnetic recording medium according to claim 19, wherein the polyether diol is obtained by the cleavage polymerization of a lactone.
Claim 27
Dependent Claim
13 words
The magnetic recording medium according to claim 25, wherein the lactone is ε-caprolactone.
Claim 28
Dependent Claim
15 words
The magnetic recording medium according to claim 19, wherein the polyether diol is polyether glycol.
Claim 29
Dependent Claim
22 words
The magnetic recording medium according to claim 27, wherein the polyether glycol is polyethylene glycol, polypropylene ether glycol or polytetramethylene ether glycol.
Claim 30
Dependent Claim
36 words
The magnetic recording medium according to claim 19, wherein the polyether ester glycol is a polyester glycol obtained by the reaction of a polyalkylene ether glycol with an aliphatic dicarboxylic acid or an aromatic dicarboxylic acid.
Claim 31
Dependent Claim
23 words
The magnetic recording medium according to claim 29, wherein the polyalkylene ether glycol is polyethylene glycol, polypropylene ether glycol or polytetramethylene ether glycol.
Claim 32
Dependent Claim
22 words
The magnetic recording medium according to claim 29, wherein the aliphatic acid is succinic acid, adipic acid, sebacic acid or azelaic acid.
Claim 33
Dependent Claim
18 words
The magnetic recording medium according to claim 29, wherein the aromatic acid is terephthalic acid or isophthalic acid.
Claim 34
Dependent Claim
20 words
The magnetic recording medium according to claim 2, wherein the short-chain diol is an aliphatic glycol or an aromatic diol.
Claim 35
Dependent Claim
24 words
The magnetic recording medium according to claim 33, wherein the aliphatic glycol is ethylene glycol, propylene glycol, 1,4-butylene glycol, 1,6-hexane glycol or neopentyl glycol.
Claim 36
Dependent Claim
30 words
The magnetic recording medium according to claim 33, wherein the aromatic diol is an ethylene oxide or propylene oxide adduct of bisphenol A or an ethylene oxide adduct of hydroquinone.
Claim 37
Dependent Claim
23 words
The magnetic recording medium according to claim 2, wherein the orgnaic diamine is an aliphatic diamine, an aromatic diamine or an alicyclic diamine.
Claim 38
Dependent Claim
23 words
The magnetic recording medium according to claim 2, wherein the organic diisocyanate is an aliphatic diisocyanate, an aromatic diisocyanate or an alicyclic diisocyanate.
Claim 39
Dependent Claim
35 words
The magnetic recording medium according to claim 2, wherein the compound having hydrophilic polar group is a diol having hydrophilic polar group, a diamine having hydrophilic polar group or a diisocyanate having hydrophilic polar group.
Claim 40
Dependent Claim
124 words
A magnetic recording medium comprising a non-magnetic substrate, a magnetic layer formed on one surface of said non-magnetic substrate and a back coating layer composed of a binder and non-magnetic pigment formed on the other surface of said non-magnetic substrate, said binder containing a thermoplastic polyurethane-urea resin hardened by a polyisocyanate and having at least one hydrophilic polar group selected from the group consisting of the groups represented by general formulas: ##STR21## wherein M is hydrogen of alkali metal and M' is hydrogen metal or hydrocarbon group, the total concentration of urea groups and urethane groups in said resin being between 1.8 and 3 m mol/g, and the concentration ratio between urea groups and urethane groups in said resin being between 0.3 and 1.6.
Claim 41
Dependent Claim
124 words
A magnetic recording medium comprising a non-magnetic substrate, a magnetic layer formed on one surface of said non-magnetic substrate and a back coating layer composed of a binder and non-magnetic pigment formed on the other surface of said non-magnetic substrate, said binder containing a thermoplastic polyurethane-urea resin hardened by a polyisocyanate and having at least one hydrophilic polar group selected from the group consisting of the groups represented by general formulas: ##STR21## wherein M is hydrogen of alkali metal and M' is hydrogen metal or hydrocarbon group, the total concentration of urea groups and urethane groups in said resin being between 1.8 and 3 m mol/g, and the concentration ratio between urea groups and urethane groups in said resin being between 0.3 and 1.6.
Claim 42
Dependent Claim
100 words
The magnetic recording medium according to claim 39, wherein the thermoplastic polyurethane-urea resin is obtained by the polyaddition reaction of (A) a long-chain diol having a molecular weight in a range of about 500 to 5000; (B) a short-chain diol having a molecular weight in a range of about 50 to 500; (C) an organic diamine; (D) an organic diisocyanate; and (E) a compound having at least one hydrophilic polar group selected from the group consisting of the groups represented by general formulas: ##STR22## wherein M is hydrogen or alkali metal and M' is hydrogen, alkali metal or hydrocarbon group.
Claim 43
Dependent Claim
20 words
The magnetic recording medium according to claim 39, wherein the thermoplastic polyurethane-urea resin is cured with a polyisocyanate curing agent.
Claim 44
Dependent Claim
25 words
The magnetic recording medium according to claim 39, wherein the concentration of hydrophilic polar group in said resin is between 0.01 and 1.0 m mol/g.
Claim 45
Dependent Claim
25 words
The magnetic recording medium according to claim 42, wherein the concentration of hydrophilic polar group in said resin is between 0.1 and 0.5 m mol/g.
Claim 46
Dependent Claim
21 words
The magnetic recording medium according to claim 39, wherein the number-average molecular weight of said resin is between 10000 and 100000.
Claim 47
Dependent Claim
21 words
The magnetic recording medium according to claim 44, wherein the number-average molecular weight of said resin is between 10000 and 60000.
Claim 48
Dependent Claim
21 words
The magnetic recording medium according to claim 39, wherein the softening point of said resin is not less than 80° C.
Claim 49
Dependent Claim
21 words
The magnetic recording medium according to claim 46, wherein the softening point of said resin is not less than 100° C.
Claim 50
Dependent Claim
22 words
The magnetic recording medium according to claim 39, wherein the glass transition point of said resin is not more than 0° C.
Claim 51
Dependent Claim
22 words
The magnetic recording medium according to claim 48, wherein the glass transition point of said resin is not more than -10° C.
Claim 52
Dependent Claim
25 words
The magnetic recording medium according to claim 40, wherein the weight ratio of the short-chain diol to the long-chain diol is not more than 3.
Claim 53
Dependent Claim
21 words
The magnetic recording medium according to claim 39, wherein the magnetic layer is composed mainly of magnetic powder and a binder.
Claim 54
Dependent Claim
19 words
The magnetic recording medium according to claim 39, wherein the magnetic layer is composed of ferromagnetic metal thin film.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1990-01-19 | 1990-07-21 | 1991-01-20 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1994-01-19 | 1994-07-21 | 1995-01-20 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1998-01-19 | 1998-07-21 | 1999-01-20 | $7700.00 | Window Closed / Lapsed |