US4189514A — Process of making high-temperature magnetic tape

Claim 1

Independent Claim 144 words

In a helically-spoolable magnetic tape comprising a substrate, a magnetic recording medium of the type comprising magnetic particles in an organic resin matrix on one face of the said substrate, and anti-static coating on the reverse side of said substrate, the improvement wherein said anti-static coating is formed with a thoroughly crosslinked organic resin binder system containing at least 50% prepolymerized polyester-type polyurethane, and comprising dispersed within said binder an effective quantity of a conductive filler from about 10 to 30% by weight of pyrogenic silica and from about 0.5 to about 3% of a silicone-oil based lubricant such weights based on the weight of organic resin binder, said anti-static coating forming an interface with said magnetic recording medium, said interface providing a means to allow unspooling of the spooled tape without any substantial damage thereto after exposure of the tape to elevated temperature.

Claim 2

Dependent Claim 144 words

In a helically-spoolable magnetic tape comprising a substrate, a magnetic recording medium of the type comprising magnetic particles in an organic resin matrix on one face of the said substrate, and anti-static coating on the reverse side of said substrate, the improvement wherein said anti-static coating is formed with a thoroughly crosslinked organic resin binder system containing at least 50% prepolymerized polyester-type polyurethane, and comprising dispersed within said binder an effective quantity of a conductive filler from about 10 to 30% by weight of pyrogenic silica and from about 0.5 to about 3% of a silicone-oil based lubricant such weights based on the weight of organic resin binder, said anti-static coating forming an interface with said magnetic recording medium, said interface providing a means to allow unspooling of the spooled tape without any substantial damage thereto after exposure of the tape to elevated temperature.

Claim 3

Dependent Claim 28 words

A magnetic tape as defined in claim 1 wherein the resin component of said organic binder in said anti-static coating comprises about 5 to 15% of phenoxy resin.

Claim 4

Dependent Claim 115 words

In a magnetic tape of the type comprising a substrate, an anti-static backing coat, and a face coat comprising ferromagnetic particles in an prepolymerized polyesterurethane resin coating, the improvement wherein said anti-static backing comprises, in addition to a pre-polymerized polyurethane based binder system and a primary filler forming means to dissipate static electricity, (1) a silicone-oil based lubricant and (2) an effective quantity of pyrogenic silica forming means to absorb any excessive lubricant and limit the migration thereof to the surface of said coating said anti-static backing coat forming an interface with said face coat, said interface providing means to allow release of said backing coat from said face coat after exposure to elevated temperatures.

Claim 5

Dependent Claim 115 words

In a magnetic tape of the type comprising a substrate, an anti-static backing coat, and a face coat comprising ferromagnetic particles in an prepolymerized polyesterurethane resin coating, the improvement wherein said anti-static backing comprises, in addition to a pre-polymerized polyurethane based binder system and a primary filler forming means to dissipate static electricity, (1) a silicone-oil based lubricant and (2) an effective quantity of pyrogenic silica forming means to absorb any excessive lubricant and limit the migration thereof to the surface of said coating said anti-static backing coat forming an interface with said face coat, said interface providing means to allow release of said backing coat from said face coat after exposure to elevated temperatures.

Claim 6

Dependent Claim 34 words

A magnetic tape as defined in claim 3 wherein said primary filler is a carbon black and said pyrogenic silica forms means to aid spatial distribution of said carbon black within said anti-static coating.

Claim 7

Dependent Claim 37 words

A magnetic tape as defined in claim 1 wherein said tape is characterized by resistance to high temperature degradation, remains unwindable and readable after subjection, in spooled form, to an environment of 400° F. for one hour.

Claim 8

Dependent Claim 39 words

A magnetic tape as defined in claim 3 wherein said tape is characterized by resistance to high temperature degradation, remains unwindable and magnetically readable after being subject, in spooled form, to an environment of 400° F. for one hour.

Annuity Stage	Window Opens	Payment Deadline	Surcharge Period Until	Estimated Fee	Status
3.5 Years (Year 4)	1983-02-18	1983-08-20	1984-02-19	$2000.00	Window Closed / Lapsed
7.5 Years (Year 8)	1987-02-18	1987-08-20	1988-02-19	$3760.00	Window Closed / Lapsed
11.5 Years (Year 12)	1991-02-18	1991-08-20	1992-02-19	$7700.00	Window Closed / Lapsed

Process of making high-temperature magnetic tape

Abstract

Inventors

Bibliographic Details

Claims Analysis

References Cited (Backward Citations)

USPTO Annuity & Maintenance Windows

Assigned Categories & Tags

Assign Category Tag