US4526833A
Expired / Lapsed
US
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Magnetic recording medium having a perfluoropolyether polymer protective coating
Assignee: 3M Co
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Filing: 1983-10-03
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Granted: 1985-07-02
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Expires: 2003-10-03
Abstract
Abstract A magnetic recording medium protected by a very thin, composite low surface energy covering is disclosed. The covering comprises a primer layer of a polymerized phosphorylated monomer or oligomer and an outer lubricant layer of perfluoropolyether polymer. The two layers may be polymerized in situ. The primer layer is made from monomers such as phosphorylated bis[4-methacryloyloxyhydroxypropylcarbamato-cyclohexyl]methane. The outer layer is made from a polymerizable perfluoropolyether monomer such as ##STR1## The composite low surface energy covering is especially useful for providing lubricity and corrosion resistance to a metallic thin-film magnetic recording coating.
Inventors
- 👤 Mario D. Burguette
- 👤 George D. Foss
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-29 21:17
CPC Classifications
C; C08; C08F; C08F299/00; C08F299/02; C08F299/022; C08F299/024; G; G11; G11B; G11B5/00; G11B5/62; G11B5/72; G11B5/725; G11B5/7253; G11B5/7257; C09; C09D; C09D171/00; C09D171/02; G11B5/726; G11B5/84; Y; Y10; Y10S; Y10S428/00; Y10S428/90; Y10T; Y10T428/00; Y10T428/26; Y10T428/263; Y10T428/264; Y10T428/265; Y10T428/31504; Y10T428/31536; Y10T428/3154; Y10T428/31544
Claims Analysis
Total Claims: 19
Claim 1
Independent Claim
81 words
A substrate, a surface of which is covered by a protective coating present in an amount sufficient to lubricate said surface and comprising: (a) a primer layer comprising a polymer made from a phosphorylated monomer or oligomer which is soluble in at least one common organic solvent and which contains at least one aromatic, cycloaliphatic or hetero atom moiety; and (b) an outer layer comprising a polymer made from at least one perfluoropolyether comprising a plurality of perfluoroalkylene oxide repeating units.
Claim 2
Dependent Claim
81 words
A substrate, a surface of which is covered by a protective coating present in an amount sufficient to lubricate said surface and comprising: (a) a primer layer comprising a polymer made from a phosphorylated monomer or oligomer which is soluble in at least one common organic solvent and which contains at least one aromatic, cycloaliphatic or hetero atom moiety; and (b) an outer layer comprising a polymer made from at least one perfluoropolyether comprising a plurality of perfluoroalkylene oxide repeating units.
Claim 3
Dependent Claim
33 words
The substrate of claim 1 which is a magnetic recording medium having a magnetizable coating on which the protective coating has a thickness in the approximate range of about 5 to 200 nanometers.
Claim 4
Dependent Claim
26 words
The magnetic recording medium of claim 2 wherein the weight ratio of the perfluoropolyether layer to the primer layer is from about 1/1 to about 5/1.
Claim 5
Dependent Claim
38 words
The magnetic recording medium of claim 3 wherein the perfluoropolyether has an average of at least about 1.5 polymerizable ethylenically unsaturated sites per molecule, and the phosphorylated monomer or oligomer has a plurality of ethylenically unsaturated polymerizable moieties.
Claim 6
Dependent Claim
104 words
The composition of claim 4 wherein the perfluoropolyether of part b. has the formula ##STR7## wherein Q comprises a polymerizable group attached to R f which represents a chain of one or more randomly distributed perfluoroalkylene oxide units selected from the group consisting of ##STR8## in which a is independently an integer of 1 to 4, k is the number of such repeating units having a value from 1 to 300 such that the segment R f preferably has a number average molecular weight of about 500 to 10,000, and Z is selected from the group consisting of --OC a F 2a+1 and Q.
Claim 7
Dependent Claim
24 words
The composition of claim 5 wherein Q of the formula is selected from the group consisting of ##STR9## wherein R is hydrogen or methyl.
Claim 8
Dependent Claim
60 words
The composition of claim 6 wherein the perfluoropolyether has the formula Q--CF.sub.2 O(CF.sub.2 CF.sub.2 O).sub.m (CF.sub.2 O).sub.n CF.sub.2 --Q wherein m and n designate the number of randomly distributed perfluoroethyleneoxy and perfluoromethyleneoxy backbone repeating units respectively, n and m having independently values of from 1 to 200, and the ratio m to n is between about 0.2/1 and about 5/1.
Claim 9
Dependent Claim
48 words
The magnetic recording medium of claim 5 wherein the primer layer is made from a compound selected from the group consisting of phosphorylated α,62 -unsaturated carboxylic acid esters of hydroxyalkyl polyhydric phenols; phosphorylated acrylates and methacrylates of glycidyl esters of dicarboxylic acids; and phosphorylated acrylates of hydroxy urethanes.
Claim 10
Dependent Claim
35 words
The magnetic recording medium of claim 8 in which the phosphorylated monomer or oligomer of part a. is selected from the group consisting of: phosphorylated bis[4-methacryloyloxyhydroxypropylcarbamato-cyclohexyl]methane; phosphorylated methacryloyloxyhydroxypropylisophthalate; and phosphorylated dimethacrylate of hydroxypropoxylated bisphenol A.
Claim 11
Dependent Claim
18 words
The magnetic recording medium as defined in claim 5 wherein said magnetizable coating is a metallic thin-film coating.
Claim 12
Dependent Claim
21 words
The magnetic recording medium as defined in claim 5 wherein said protective coating has a thickness of 5 to 25 nm.
Claim 13
Independent Claim
206 words
A method of making a magnetic recording medium with a protective coating on the surface of the magnetizable coating of said medium, comprising the steps of: (i) coating onto said surface a dilute solution of a polymerizable phosphorylated monomer or oligomer containing at least one aromatic, cycloaliphatic or hetero atom moiety, said solution being in a common organic solvent to provide a primer coating; (ii) coating over the primer coating a second dilute solution of perfluoropolyether monomer having an average of at least about 1.5 ethylenically unsaturated polymerizable sites per molecule and having the formula ##STR10## wherein Q comprises a polymerizable group attached to R f which represents a chain of one or more randomly distributed perfluoroalkylene oxide units selected from the group consisting of ##STR11## in which a is independently an integer of 1 to 4, k is the number of such repeating units having a value from 1 to 300 such that the segment R f preferably has a number average molecular weight of about 500 to 10,000, and Z is selected from the group consisting of --OC a F 2a+1 and Q; (iii) drying said coatings; and (iv) polymerizing the dried coatings, the thickness of the resulting protective coating not exceeding 200 nm.
Claim 14
Independent Claim
206 words
A method of making a magnetic recording medium with a protective coating on the surface of the magnetizable coating of said medium, comprising the steps of: (i) coating onto said surface a dilute solution of a polymerizable phosphorylated monomer or oligomer containing at least one aromatic, cycloaliphatic or hetero atom moiety, said solution being in a common organic solvent to provide a primer coating; (ii) coating over the primer coating a second dilute solution of perfluoropolyether monomer having an average of at least about 1.5 ethylenically unsaturated polymerizable sites per molecule and having the formula ##STR10## wherein Q comprises a polymerizable group attached to R f which represents a chain of one or more randomly distributed perfluoroalkylene oxide units selected from the group consisting of ##STR11## in which a is independently an integer of 1 to 4, k is the number of such repeating units having a value from 1 to 300 such that the segment R f preferably has a number average molecular weight of about 500 to 10,000, and Z is selected from the group consisting of --OC a F 2a+1 and Q; (iii) drying said coatings; and (iv) polymerizing the dried coatings, the thickness of the resulting protective coating not exceeding 200 nm.
Claim 15
Dependent Claim
43 words
The method of claim 12 wherein the phosphorylated monomer or oligomer is selected from the group consisting of phosphorylated α,β-unsaturated carboxylic acid esters of hydroxyalkyl polyhydric phenols; phosphorylated acrylates and methacrylates of glycidyl esters of dicarboxylic acids; and phosphorylated acrylates of hydroxy urethanes.
Claim 16
Dependent Claim
24 words
The method of claim 12 which further comprises drying the primer coating of step (i) to remove most of the solvent before step (ii).
Claim 17
Dependent Claim
17 words
Method as defined in claim 14 wherein step (iv) comprises exposing the two coatings to ultraviolet radiation.
Claim 18
Dependent Claim
31 words
The method of claim 14 wherein the weight ratio of the perfluoropolyether of step (ii) to the phosphorylated monomer or oligomer of step (i) is from about 1/1 to about 5/1.
Claim 19
Dependent Claim
30 words
The method of claim 12 wherein the solvent for step (i) is selected from the group consisting of methylethyl ketone, methylisobutylketone, tetrahydrofuran, toluene, benzene, xylene, cyclohexanone, ethanol and mixtures thereof.
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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) | 1988-07-01 | 1988-12-31 | 1989-07-02 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1992-07-01 | 1992-12-31 | 1993-07-02 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1996-07-01 | 1996-12-31 | 1997-07-02 | $7700.00 | Window Closed / Lapsed |