US4490505A
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Polyfunctional aziridine crosslinking agents for aqueous magnetic recording media binder
Assignee: 3M Co
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Filing: 1981-03-16
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Granted: 1984-12-25
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Expires: 2001-03-16
Abstract
Abstract In the manufacture of magnetic recording media, coatings are applied from water-borne dispersions of inorganic particles, a polymer containing functional groups and an agent for crosslinking the polymer, the crosslinking agent being a polyfunctional aziridine such as ##STR1##
Inventors
- 👤 Daniel B. Pendergrass, Jr.
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-27 08:37
CPC Classifications
G; G11; G11B; G11B5/00; G11B5/62; G11B5/68; G11B5/70; G11B5/702; C; C08; C08K; C08K5/00; C08K5/16; C08K5/34; C08K5/3412; Y; Y10; Y10S; Y10S428/00; Y10S428/90; Y10T; Y10T428/00; Y10T428/23; Y10T428/231; Y10T428/31504; Y10T428/31511; Y10T428/31551; Y10T428/31565; Y10T428/31678; Y10T428/31681
Claims Analysis
Total Claims: 30
Claim 1
Independent Claim
101 words
A method of making a magnetic recording medium comprising a backing member and a magnetizable layer, which method comprises the steps of (1) preparing a dispersion of inorganic particles in a water-borne polymer having active-hydrogen, epoxy or epithio functional groups, (2) adding a crosslinking agent to the dispersion, and (3) coating the thus-modified dispersion onto the backing member, wherein the improvement comprises: the crosslinking agent is a polyfunctional aziridine having the formula ##STR10## where Q is a n-valent inorganic or aliphatic, aromatic or alicyclic organic radical, n is at least 2, and each of R' and R" is hydrogen or alkyl.
Claim 2
Independent Claim
101 words
A method of making a magnetic recording medium comprising a backing member and a magnetizable layer, which method comprises the steps of (1) preparing a dispersion of inorganic particles in a water-borne polymer having active-hydrogen, epoxy or epithio functional groups, (2) adding a crosslinking agent to the dispersion, and (3) coating the thus-modified dispersion onto the backing member, wherein the improvement comprises: the crosslinking agent is a polyfunctional aziridine having the formula ##STR10## where Q is a n-valent inorganic or aliphatic, aromatic or alicyclic organic radical, n is at least 2, and each of R' and R" is hydrogen or alkyl.
Claim 3
Dependent Claim
18 words
A method as defined in claim 1, wherein the improvement further comprises: said inorganic particles are magnetizable particles.
Claim 4
Dependent Claim
33 words
A method as defined in claim 1, wherein the improvement further comprises: ##STR11## where R is an n-valent aliphatic, aromatic or alicyclic radical, and each of x and y is 0 or 2.
Claim 5
Dependent Claim
17 words
A method as defined in claim 3, wherein the improvement further comprises: the polyfunctional aziridine is ##STR12##
Claim 6
Dependent Claim
14 words
Magnetic recording medium made by a method as defined by claims 1 or 2.
Claim 7
Dependent Claim
72 words
Magnetic recording medium comprising a backing member carrying a water-borne layer of inorganic particles in a binder comprising a crosslinked polymer which had active-hydrogen, epoxy or epithio functional groups, wherein the improvement comprises: the crosslinking agent was a polyfunctional aziridine having the formula ##STR13## where Q is a n-valent inorganic or aliphatic, aromatic or alicyclic organic radical, n is at least 2, and each of R' and R" is hydrogen or alkyl.
Claim 8
Dependent Claim
72 words
Magnetic recording medium comprising a backing member carrying a water-borne layer of inorganic particles in a binder comprising a crosslinked polymer which had active-hydrogen, epoxy or epithio functional groups, wherein the improvement comprises: the crosslinking agent was a polyfunctional aziridine having the formula ##STR13## where Q is a n-valent inorganic or aliphatic, aromatic or alicyclic organic radical, n is at least 2, and each of R' and R" is hydrogen or alkyl.
Claim 9
Dependent Claim
15 words
Magnetic recording medium as defined in claim 6 wherein said inorganic particles are magnetizable particles.
Claim 10
Dependent Claim
70 words
A water-borne dispersion for making coatings of magnetic recording media, said dispersion comprising inorganic particles, a water-borne polymer having active-hydrogen, epoxy or epithio functional groups, and 2-25% by weight of said polymer of a polyfunctional aziridine crosslinking agent having the formula ##STR14## where Q is a n-valent inorganic or aliphatic, aromatic or alicyclic organic radical, n is at least 2, and each of R' and R" is hydrogen or alkyl.
Claim 11
Dependent Claim
70 words
A water-borne dispersion for making coatings of magnetic recording media, said dispersion comprising inorganic particles, a water-borne polymer having active-hydrogen, epoxy or epithio functional groups, and 2-25% by weight of said polymer of a polyfunctional aziridine crosslinking agent having the formula ##STR14## where Q is a n-valent inorganic or aliphatic, aromatic or alicyclic organic radical, n is at least 2, and each of R' and R" is hydrogen or alkyl.
Claim 12
Dependent Claim
76 words
A coatable dispersion of inorganic particles in a water-borne polymer for making coatings of magnetic recording media, which polymer has active-hydrogen, epoxy or epithio functional groups, wherein the improvement comprises: the dispersion includes 2-25% by weight of said polymer of a polyfunctional aziridine crosslinking agent having the formula ##STR15## where Q is n-valent inorganic or aliphatic, aromatic or alicyclic organic radical, n is at least 2, and each of R' and R" is hydrogen or alkyl.
Claim 13
Dependent Claim
76 words
A coatable dispersion of inorganic particles in a water-borne polymer for making coatings of magnetic recording media, which polymer has active-hydrogen, epoxy or epithio functional groups, wherein the improvement comprises: the dispersion includes 2-25% by weight of said polymer of a polyfunctional aziridine crosslinking agent having the formula ##STR15## where Q is n-valent inorganic or aliphatic, aromatic or alicyclic organic radical, n is at least 2, and each of R' and R" is hydrogen or alkyl.
Claim 14
Dependent Claim
14 words
A dispersion as defined in claim 8, wherein said inorganic particles are magnetizable particles.
Claim 15
Dependent Claim
31 words
A dispersion as defined in claim 10, wherein Q is ##STR16## where R is an n-valent aliphatic, aromatic or alicyclic radical, and each of x and y is 0 or 2.
Claim 16
Dependent Claim
13 words
A dispersion as defined in claim 11, wherein the polyfunctional aziridine is ##STR17##
Claim 17
Independent Claim
93 words
A method of making a magnetic recording medium comprising a backing member and a magnetizable layer, which method comprises the steps of (1) preparing a dispersion of inorganic particles in a water-borne polyurethane having pendant carboxylic acid groups, (2) adding a polyfunctional aziridine crosslinking agent to the dispersion, and (3) coating the thus-modified dispersion onto the backing member, said polyfunctional aziridine having the formula ##STR18## where Q is a n-valent inorganic or aliphatic, aromatic or alicyclic organic radical, n is at least 2, and each of R' and R" is hydrogen or alkyl.
Claim 18
Independent Claim
93 words
A method of making a magnetic recording medium comprising a backing member and a magnetizable layer, which method comprises the steps of (1) preparing a dispersion of inorganic particles in a water-borne polyurethane having pendant carboxylic acid groups, (2) adding a polyfunctional aziridine crosslinking agent to the dispersion, and (3) coating the thus-modified dispersion onto the backing member, said polyfunctional aziridine having the formula ##STR18## where Q is a n-valent inorganic or aliphatic, aromatic or alicyclic organic radical, n is at least 2, and each of R' and R" is hydrogen or alkyl.
Claim 19
Dependent Claim
14 words
A method as defined in claim 13, wherein said inorganic particles are magnetizable particles.
Claim 20
Dependent Claim
66 words
Magnetic recording medium comprising a backing member carrying a water-borne layer of inorganic particles in a binder comprising a crosslinked polyurethane having pendant carboxylic acid groups, wherein the crosslinking agent was a polyfunctional aziridine having the formula ##STR19## where Q is a n-valent inorganic or aliphatic, aromatic or alicyclic organic radical, n is at least 2, and each of R' and R" is hydrogen or alkyl.
Claim 21
Dependent Claim
66 words
Magnetic recording medium comprising a backing member carrying a water-borne layer of inorganic particles in a binder comprising a crosslinked polyurethane having pendant carboxylic acid groups, wherein the crosslinking agent was a polyfunctional aziridine having the formula ##STR19## where Q is a n-valent inorganic or aliphatic, aromatic or alicyclic organic radical, n is at least 2, and each of R' and R" is hydrogen or alkyl.
Claim 22
Dependent Claim
15 words
Magnetic recording medium as defined in claim 15, wherein said inorganic particles are magnetizable particles.
Claim 23
Dependent Claim
37 words
An aqueous coating composition for forming a magnetic recording layer, said coating composition comprising an aqueous dispersion of magnetic pigment, polyurethane with carboxylic acid groups on the backbone chain, and a polyfunctional crosslinking agent for said polyurethane.
Claim 24
Dependent Claim
37 words
An aqueous coating composition for forming a magnetic recording layer, said coating composition comprising an aqueous dispersion of magnetic pigment, polyurethane with carboxylic acid groups on the backbone chain, and a polyfunctional crosslinking agent for said polyurethane.
Claim 25
Dependent Claim
15 words
The coating composition of claim 17 in which said crosslinking agent comprises a polyfunctional aziridine.
Claim 26
Dependent Claim
35 words
A water-born dispersion for forming a magnetic recording layer, said dispersion having a pH above about 7 and comprising magnetizable particles, polyurethane having pendant carboxylic acid groups, and a polyfunctional crosslinking agent for said polyurethane.
Claim 27
Dependent Claim
35 words
A water-born dispersion for forming a magnetic recording layer, said dispersion having a pH above about 7 and comprising magnetizable particles, polyurethane having pendant carboxylic acid groups, and a polyfunctional crosslinking agent for said polyurethane.
Claim 28
Dependent Claim
14 words
The dispersion of claim 19 in which said crosslinking agent comprises a polyfunctional aziridine.
Claim 29
Dependent Claim
24 words
A method as defined in claim 1, wherein the improvement further comprises: said polyfunctional aziridine is employed at 2-25% by weight of said polymer.
Claim 30
Dependent Claim
21 words
Magnetic recording medium as defined in claim 6 wherein said polyfunctional aziridine was employed at 2-25% by weight of said polymer.
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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) | 1987-12-25 | 1988-06-25 | 1988-12-25 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1991-12-25 | 1992-06-25 | 1992-12-25 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1995-12-25 | 1996-06-25 | 1996-12-25 | $7700.00 | Window Closed / Lapsed |