Patent US4435485A successfully refreshed from Google Patents.
US4435485A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Magnetic recording medium
Assignee: Shin-Etsu Chemical Co Ltd
•
Filing: 1981-08-24
•
Granted: 1984-03-06
•
Expires: 2001-08-24
Abstract
Abstract The magnetic recording medium contains the magnetic layer comprising the magnetic or magnetizable powders or particles and the binder comprising a composition containing (A) a compound represented by formula (V): <IMAGE> (wherein R is methyl or ethyl group and X is a group containing an acrylic or methacrylic double bond; i is a number in the range of approximately 200 to 800, j is a number in the range of approximately 10 to 200, k is a number in the range up to approximately 200, and l is a number in the range of approximately 3 to 100, provided that the division of l by the sum of k and l is in the range from approximately 0.2 to 1.0) and (B) a compound having at least two acrylic and/or methacrylic double bonds in the molecule thereof and having a molecular weight ranging from approximately 1,000 to 6,000 in which the molecular weight in the molecule per one double bond is in the range from approximately 80 to 3,000. The composition is cured by the irradiation of radiation so that the magnetic recording medium has an improved durability as well as physical strengths in the magnetic layer thereon.
Inventors
- 👤 Kaoru Nakajima
- 👤 Masashi Somezawa
- 👤 Minoru Takamizawa
- 👤 Yoshio Inoue
- 👤 Hiroshi Yoshioka
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-30 23:28
CPC Classifications
G; G11; G11B; G11B5/00; G11B5/62; G11B5/68; G11B5/70; G11B5/702; G11B5/7026; G11B5/7023; Y; Y10; Y10S; Y10S428/00; Y10S428/90; Y10T; Y10T428/00; Y10T428/31504; Y10T428/31786
Claims Analysis
Total Claims: 8
Claim 1
Independent Claim
214 words
A magnetic recording medium having a magnetic layer comprising magnetic or magnetizable powders or particles and a binder comprising a composition containing (A) a compound having components represented by recurring units having the following formulas: ##STR7## (wherein R is methyl or ethyl group); ##STR8## (wherein X is a group consisting an acrylic or methacrylic double bond); and, ##STR9## in which the number of recurring units represented as Unit (I) ranges from approximately 200 to 800; the number of recurring units represented by Unit (II) ranges from approximately 10 to 200; the number of recurring units represented by Unit (III) ranges from approximately 3 to 100; and the number of recurring units represented by Unit (IV) is optionally in the range up approximately 200; and (B) a compound having at least two acrylic and/or methacrylic double bonds in the molecule thereof and having a molecular weight ranging from approximately 1,000 to 6,000 in which the molecular weight in the molecule thereof per one double bond is in the range from approximately 80 to 3,000; and said composition used as the binder is cured by irradiation and wherein the composition comprises the compound (A) in the amount ranging from approximately 20 to 80% and the compound (B) in the amount ranging from approximately 80 to 20%.
Claim 2
Dependent Claim
214 words
A magnetic recording medium having a magnetic layer comprising magnetic or magnetizable powders or particles and a binder comprising a composition containing (A) a compound having components represented by recurring units having the following formulas: ##STR7## (wherein R is methyl or ethyl group); ##STR8## (wherein X is a group consisting an acrylic or methacrylic double bond); and, ##STR9## in which the number of recurring units represented as Unit (I) ranges from approximately 200 to 800; the number of recurring units represented by Unit (II) ranges from approximately 10 to 200; the number of recurring units represented by Unit (III) ranges from approximately 3 to 100; and the number of recurring units represented by Unit (IV) is optionally in the range up approximately 200; and (B) a compound having at least two acrylic and/or methacrylic double bonds in the molecule thereof and having a molecular weight ranging from approximately 1,000 to 6,000 in which the molecular weight in the molecule thereof per one double bond is in the range from approximately 80 to 3,000; and said composition used as the binder is cured by irradiation and wherein the composition comprises the compound (A) in the amount ranging from approximately 20 to 80% and the compound (B) in the amount ranging from approximately 80 to 20%.
Claim 3
Dependent Claim
99 words
A magnetic recording medium according to claim 1, wherein the compound (A) is represented by formula (V): ##STR10## (wherein R and X have the same meanings as represented hereinabove, i is a number in the range of approximately 200 to 800, j is a number in the range of approximately 10 to 200, k is a number in the range up to approximately 200, and l is a number in the range of approximately 3 to 100, provided that the division of l by the sum of k and l is in the range from approximately 0.2 to 1.0).
Claim 4
Dependent Claim
59 words
A magnetic recording medium according to claim 1, wherein the compound (A) is a vinyl chloride-vinyl acetate-vinyl alcohol modified so as to provide a methacrylation degree of 40% or 80% and the compound (B) is an oligourethane methacrylate obtained by reacting 1 mole of trimethylolpropane with 3 moles of toluene diisocyanate and then with 3 moles of 2-hydroxyethyl acrylate.
Claim 5
Dependent Claim
25 words
A magnetic recording medium according to claim 1, wherein the composition is cured by irradiation in the amount ranging from approximately 1 to 10 Mrad.
Claim 6
Dependent Claim
20 words
A magnetic recording medium according to claim 4, wherein the amount of radiation ranges from approximately 2 to 7 Mrad.
Claim 7
Dependent Claim
25 words
A magnetic recording medium according to claim 2 wherein the composition is cured by irradiation in an amount ranging from approximately 1 to 10 Mrad.
Claim 8
Dependent Claim
25 words
A magnetic recording medium according to claim 3 wherein the composition is cured by irradiation in an amount ranging from approximately 1 to 10 Mrad.
References Cited (Backward Citations)
US4068040A
Cited
US4058124A
Cited
US4260466A
Cited
US4224357A
Cited
US4313989A
Cited
US4335183A
Cited
US4368242A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1987-03-06 | 1987-09-05 | 1988-03-06 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1991-03-06 | 1991-09-05 | 1992-03-06 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1995-03-06 | 1995-09-05 | 1996-03-06 | $7700.00 | Window Closed / Lapsed |