Claims
- 1. A magnetic recording medium comprising a magnetic layer composed principallyof magnetic particles and a binder, characterized in that at least a portion of the binder is a polyurethane resin synthesized from a reactant mixture of components (1), (2), (3) and (4) set out below, containing one phosphoric acid group or one residualg roup derived from phosphoric acid per 3,000-200,000 number average molecular weight of the polyurethane resin, and having a number average molecular weight of 4,000-150,000:
- (1) a phosphorus compound (a) represented by a structural formula set out below or a phosphorus compound (b) represented by a structural formula set out below: ##STR5## wherein R.sup.1 is a hydrogen atom, a phenyl group, an aklyl group having 1-40 carbon atoms, or an alkylphenyl group having 1-40 carbon atoms, and n is an integer of 0-30; ##STR6## wherein R.sup.2 is a phenyl group, an alkyl group having 1-40 carbon atoms, or an alkylphenyl group having 1-40 carbon atoms;
- (2) an epoxy compound having at least two epoxy groups and/or an epoxy compound having one epoxy roupand at least one hydroxyl group;
- (3) a bifunctional isocyanate compound and/or a trifunctional isocyanate compound; and
- (4) a polyfunctional hydroxy compound having a number average molecular weight of 400-5,000.
- 2. The magnetic recording medium according to claim 1, wherein the reactant mixture further comprises a component (5) a chain extender.
- 3. The magnetic recording medium according to claim 1, wherein phosphoric acid groups or residual groups derived from phosphoric acid, said groups being contained in the polyurethane resin, have been at least partly neutralized with a base.
- 4. The magnetic recording medium according to claim 2, wherein phosphoric acid groups or residual groups derived from phosphoric acid, said groups being contained in the polyurethane resin, have been at least partly neutralized with a base.
Priority Claims (3)
Number |
Date |
Country |
Kind |
63-271035 |
Oct 1988 |
JPX |
|
1-126580 |
May 1989 |
JPX |
|
1-203738 |
Aug 1989 |
JPX |
|
Parent Case Info
This is a division of parent application Ser. No. 07/426,132 filed on Oct. 24, 1989, U.S. Pat. No. 5,037,934.
US Referenced Citations (11)
Number |
Name |
Date |
Kind |
3350478 |
Cherbuliez et al. |
Oct 1967 |
|
3350479 |
Cherbuliez et al. |
Oct 1967 |
|
3350480 |
Cherbuliez et al. |
Oct 1967 |
|
3350481 |
Cherbuliez et al. |
Oct 1967 |
|
3365531 |
Cherbuliez et al. |
Jan 1968 |
|
3373231 |
Cherbuliez et al. |
Mar 1968 |
|
3374294 |
Cherbuliez et al. |
Mar 1968 |
|
4571364 |
Kasuga et al. |
Feb 1986 |
|
4830923 |
Sumiya et al. |
May 1989 |
|
5045622 |
Kohno et al. |
Sep 1991 |
|
5057373 |
Tokunaga et al. |
Oct 1991 |
|
Divisions (1)
|
Number |
Date |
Country |
Parent |
426132 |
Oct 1989 |
|