US5082733A — Magnetic recording medium containing magnetic par…

Claim 1

Independent Claim 162 words

A magnetic recording medium comprising a nonmagnetic support having thereon a magnetic recording layer which contains ferromagnetic particles dispersed in a binder, wherein the ferromagnetic particles have been surface-treated with a glycidyl compound having a molecular weight of 1,000 or less and having an epoxy equivalent of 200 g/eq. or less, wherein surface-treatment of the magnetic particles has been carried out by a process which comprises dispersing the glycidyl compound and the ferromagnetic particles in a portion of a solvent used for preparing a magnetic coating composition to form a first solution, and wherein a binder is added to the remainder of the solvent to form a second solution, and then the first and second solutions are added together, and the resultant mixture is then mixed, kneaded and dispersed to prepare a magnetic coating composition, and thereafter the resulting magnetic coating composition is coated on the nonmagnetic support, and then the magnetic coating composition is dried to form the magnetic recording layer.

Claim 2

Dependent Claim 162 words

A magnetic recording medium comprising a nonmagnetic support having thereon a magnetic recording layer which contains ferromagnetic particles dispersed in a binder, wherein the ferromagnetic particles have been surface-treated with a glycidyl compound having a molecular weight of 1,000 or less and having an epoxy equivalent of 200 g/eq. or less, wherein surface-treatment of the magnetic particles has been carried out by a process which comprises dispersing the glycidyl compound and the ferromagnetic particles in a portion of a solvent used for preparing a magnetic coating composition to form a first solution, and wherein a binder is added to the remainder of the solvent to form a second solution, and then the first and second solutions are added together, and the resultant mixture is then mixed, kneaded and dispersed to prepare a magnetic coating composition, and thereafter the resulting magnetic coating composition is coated on the nonmagnetic support, and then the magnetic coating composition is dried to form the magnetic recording layer.

Claim 3

Independent Claim 134 words

A method for preparing a magnetic recording medium comprising the steps of (1) surface-treating ferromagnetic particles with a glycidyl compound having a molecular weight of 1,000 or less and having an epoxy equivalent of 200 g/eq. or less, wherein the step of surface-treating the magnetic particles comprises dispersing the glycidyl compound and the ferromagnetic particles in a portion of a solvent used for preparing a magnetic coating composition to form a first solution, (2) a binder is added to the remainder of the solvent to form a second solution, and then the first and second solutions are added together, and the resultant mixture is then mixed, kneaded and dispersed to prepare the magnetic coating composition, (3) coating the resulting magnetic coating composition on a nonmagnetic support, and then (4) drying the magnetic coating composition.

Claim 4

Independent Claim 134 words

A method for preparing a magnetic recording medium comprising the steps of (1) surface-treating ferromagnetic particles with a glycidyl compound having a molecular weight of 1,000 or less and having an epoxy equivalent of 200 g/eq. or less, wherein the step of surface-treating the magnetic particles comprises dispersing the glycidyl compound and the ferromagnetic particles in a portion of a solvent used for preparing a magnetic coating composition to form a first solution, (2) a binder is added to the remainder of the solvent to form a second solution, and then the first and second solutions are added together, and the resultant mixture is then mixed, kneaded and dispersed to prepare the magnetic coating composition, (3) coating the resulting magnetic coating composition on a nonmagnetic support, and then (4) drying the magnetic coating composition.

Claim 5

Dependent Claim 56 words

The method for preparing a magnetic recording medium as in claim 2, wherein the step of surface-treating the ferromagnetic particles comprises dissolving the glycidyl compound in an organic solvent having a low boiling point, adding the ferromagnetic particles into the organic solvent, mixing the ferromagnetic particles with the organic solvent, and then removing the organic solvent.

Claim 6

Dependent Claim 71 words

The method for preparing a magnetic recording medium as in claim 2, wherein the glycidyl compound is at least one compound selected from the group consisting of a bisphenol A epoxy resin, a glycidylamine epoxy resin, a novolak epoxy resin, a bisphenol F resin, a glycidyl ester resin, an alicyclic epoxy resin, an aliphatic epoxy resin, glycidyl methacrylate, glycidyl phenyl ether, a resorcinol diglycidyl ether resin, and a resorcinol epoxy resin.

Claim 7

Dependent Claim 41 words

The method for preparing a magnetic recording medium as in claim 4, wherein the bisphenol A epoxy resin is represented by formula (A): ##STR13## wherein R is H or CH 3 ; and n is an integer of 0 to 3.

Claim 8

Dependent Claim 68 words

The method for preparing a magnetic recording medium as in claim 4, wherein the glycidylamine epoxy resin is represented by formulae (B 1 ), (B 2 ), or (B 3 ): ##STR14## wherein R 1 is ##STR15## wherein (o, m, p) means bonding is possible at any of the ortho, meta, or para positions; R 2 is ##STR16## or a hydrocarbon having from 4 to 24 carbon atoms.

Claim 9

Dependent Claim 42 words

The method for preparing a magnetic recording medium as in claim 4, wherein the magnetic epoxy resin is represented by formula (C): ##STR17## wherein R 3 is H or CH 3 , and n is an integer of from 0 to 10.

Claim 10

Dependent Claim 33 words

The method for preparing a magnetic recording medium as in claim 4, wherein the bisphenol F epoxy resin is represented by formula (D): ##STR18## wherein R 4 is H or CH 3 .

Claim 11

Dependent Claim 42 words

The method for preparing a magnetic recording medium as in claim 4, wherein the glycidyl ester resin is represented by formula (E): ##STR19## wherein R 5 is ##STR20## (which can be bonded at any of the ortho, meta, or para positions), ##STR21##

Claim 12

Dependent Claim 25 words

The method for preparing a magnetic recording medium as in claim 4, wherein the glycidyl ether (resorcinol diglycidyl resin) is represented by formula (F): ##STR22##

Claim 13

Dependent Claim 39 words

The method for preparing a magnetic recording medium as in claim 2, wherein the glycidyl compound is present in an amount of from 0.1 to 7 parts by weight based on 100 parts by weight of the ferromagnetic particles.

Claim 14

Dependent Claim 39 words

The method for preparing a magnetic recording medium as in claim 11, wherein the glycidyl compound is present in an amount of from 0.15 to 6 parts by weight based on 100 parts by weight of the ferromagnetic particles.

Claim 15

Dependent Claim 38 words

The method for preparing a magnetic recording medium as in claim 2, wherein the binder is present in an amount of from 10 to 40 parts by weight based on 100 parts by weight of the ferromagnetic particles.

Claim 16

Dependent Claim 24 words

The method for preparing a magnetic recording medium as in claim 2, wherein the binder is a polyurethane resin and a vinyl chloride copolymer.

Annuity Stage	Window Opens	Payment Deadline	Surcharge Period Until	Estimated Fee	Status
3.5 Years (Year 4)	1995-01-20	1995-07-22	1996-01-21	$2000.00	Window Closed / Lapsed
7.5 Years (Year 8)	1999-01-20	1999-07-22	2000-01-21	$3760.00	Window Closed / Lapsed
11.5 Years (Year 12)	2003-01-20	2003-07-22	2004-01-21	$7700.00	Window Closed / Lapsed

Magnetic recording medium containing magnetic particles surface treated with a glycidyl compound

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