Claims
- 1. A process for producing a magnetic recording medium comprising:
- (i) treating magnetic metal particles with a passivating reaction product to form a treated pigment;
- (ii) mixing said treated pigment, a binder for said treated pigment and an inert organic solvent capable of dissolving said binder, to obtain a uniform dispersion thereof;
- (iii) coating said dispersion onto a non-magnetic substrate;
- (iv) orienting said treated pigment in a magnetic field; and
- (v) removing said solvent from the coated substrate, said passivating reaction product comprising the reaction product of
- (I) an organic halide having the formula
- X--R"
- wherein X is selected from the chlorine or bromine radical, and R" is selected from alkyl radicals having 8 to 20 carbon atoms or the group ##STR20## in which n is an integer between 8 and 22, inclusive, and a reactant selected from
- (II) a silylalkyl ester of phosphorus having the formula ##STR21## wherein Me denotes the methyl radical, Q is selected from --OMe or an alkyl group having from 1 to 4 carbon atoms, R' is a divalent hydrocarbyl group having 3 to 8 carbon atoms, and R is an alkyl group having 1 to 3 carbon atoms, or a mixture of
- (III) an organic phosphate having the formula ##STR22## and (IV) an haloalkyl-functional silane having the formula
- X--R'Si(OR).sub.3
- wherein the symbols have their previously defined meanings.
- 2. The process according to claim 1, wherein X is chlorine.
- 3. The process according to claim 2, wherein R is the methyl radical.
- 4. The process according to claim 3, wherein Q is selected from the methoxy group or the methyl radical.
- 5. The process according to claim 4, wherein R' is the trimethylene group.
- 6. The process according to claim 5, wherein R" is the n-octadecyl radical.
- 7. The process according to claim 5, wherein R" is the ##STR23## radical.
- 8. The process according to claim 1, wherein said magnetic metal particles are acicular iron particles.
Parent Case Info
This is a divisional of copending application Ser. No. 148,304, filed on Jan. 25, 1988, now U.S. Pat. No. 4,780,148.
Divisions (1)
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Number |
Date |
Country |
Parent |
148304 |
Jan 1988 |
|