# US 4,397,751 A · Magnetic disk coatings

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- Number: US 4,397,751 A
- Document ID: US4397751A
- Status: Granted
- Kind: A
- Application number: 06/260,440
- Filed: 1981-05-04
- Granted: 1983-08-09
- Earliest claimed: 1981-05-04
- Assignees: International Business Machines Corporation
- Inventors: Heidi L. Dickstein; William H. Dickstein
- Web page: https://patentgrep.com/patent/US4397751A

## CPC

- G11B 5/7028: {Additives, e.g. crosslinking agents}
- C09D 161/06: of aldehydes with phenols
- C09D 163/00: Coating compositions based on epoxy resins; Coating compositions based on derivatives of epoxy resins
- G11B 5/7023: {containing polyesters, polyethers, silicones, polyvinyl resins, polyacrylresins or epoxy resins (G11B5/7022 takes precedence)}
- Y10S 428/90: Magnetic feature
- G11B: INFORMATION STORAGE BASED ON RELATIVE MOVEMENT BETWEEN RECORD CARRIER AND TRANSDUCER (recording measured values in a way that does not require playback through a transducer G01D9/00; recording or playback apparatus using mechanically marked tape, e.g. punched paper tape, or using unit records, e.g. punched or magnetically marked cards G06K; transferring data from one type of record carrier to another G06K1/18; circuits for coupling output of reproducer to radio receiver H04B1/20; gramophone pick-ups or like acoustic electromechanical transducers or circuits therefor H04R)
- C09D: COATING COMPOSITIONS, e.g. PAINTS, VARNISHES OR LACQUERS; FILLING PASTES; CHEMICAL PAINT OR INK REMOVERS; INKS; CORRECTING FLUIDS; WOODSTAINS; PASTES OR SOLIDS FOR COLOURING OR PRINTING; USE OF MATERIALS THEREFOR (cosmetics A61K; processes for applying liquids or other fluent materials to surfaces, in general, B05D; staining wood B27K5/02; glazes or vitreous enamels C03C; natural resins, French polish, drying-oils, driers, turpentine, per se, C09F; polishing compositions other than French polish, ski waxes C09G; adhesives or use of materials as adhesives C09J; materials for sealing or packing joints or covers C09K3/10; materials for stopping leaks C09K3/12; processes for the electrolytic or electrophoretic production of coatings C25D)
- Y10S: TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS

## Abstract

A magnetic disk coating composition contains magnetic particles and a binder system comprising epoxy and phenolic resins, a titanate coupling agent and a water miscible solvent system, the coating having a pigment volume concentration of up to 35.

## Claims

### Claim 1

A mixture for coating a magnetic recording member to produce a magnetic coating having magnetic particles in a binder system in a pigment volume concentration of up to 35, where pigment volume concentration is defined as the ratio of the volume of said magnetic particles to the sum of the volume of said binder system and the volume of said magnetic particles, comprising
said binder system including
a water-miscible solvent system comprising glycol ethyl ether, hydroxyethylacetate and diethyleneglycolbutylether,
an epoxy resin selected from a group of epoxy resins which are soluble in each component of said water-miscible solvent system,
a phenolic resin selected from a group of phenolic resins which are soluble in each component of said water-miscible solvent system, and
a titanate coupling agent for improving the bond of said magnetic particles to said resins and for catalyzing the cross-linking of said resins,
each of said components of said water-miscible solvent system being compatible with said titanate coupling agent.

### Claim 2 (depends on 1)

A mixture in accordance with claim 1, in which
said binder system includes at least one flow additive material.

### Claim 3 (depends on 1)

A mixture in accordance with claim 1, in which the ingredients are present in said mixture in the following range of proportions:
______________________________________ Ingredient Parts (Weight/weight) ______________________________________ Epoxy Resin 20-26 Phenolic Resin 40-52 Titanate Coupling Agent 0.5-2.0 Water Miscible Solvents 150-190 Magnetic Particles 80-110 ______________________________________

### Claim 4 (depends on 1)

A mixture in accordance with claim 1, in which the ingredients are present in said mixture in the following proportions:
______________________________________ Ingredient Parts (Weight/weight) ______________________________________ Epoxy Resin 24 Phenolic Resin 48 Titanate Coupling Agent 1.4 Water Miscible Solvents 174 Magnetic Particles 95 ______________________________________

### Claim 5 (depends on 3)

A mixture in accordance with claim 3, including at least one flow additive material present in a range from 3 to 7 parts weight/weight.

### Claim 6 (depends on 1)

A mixture in accordance with claim 1, including at least one flow additive material present in an amount of 5 parts weight/weight.