MAGNETIC TAPE AND METHOD OF MANUFACTURING THE SAME
First Claim
1. A magnetic tape,which comprises, on one surface of a nonmagnetic support, a magnetic layer comprising ferromagnetic powder and binder, and on the other surface of the nonmagnetic support, a backcoat layer comprising nonmagnetic powder and binder, wherein:
- a centerline average surface roughness Ra on a surface on the magnetic layer side of the magnetic tape is less than or equal to 1.8 nm;
a coefficient of friction measured on a base portion of the surface on the magnetic layer side of the magnetic tape is less than or equal to 0.35;
a centerline average surface roughness Ra measured on a surface on the backcoat layer side of the magnetic tape is less than or equal to 5.0 nm;
the backcoat layer comprises a fatty acid ester,a full width at half maximum of a spacing distribution measured by optical interferometry on the surface on the backcoat layer side of the magnetic tape before vacuum heating the magnetic tape is greater than 0 nm but less than or equal to 10.0 nm;
a full width at half maximum of a spacing distribution measured by optical interferometry on the surface on the backcoat layer side of the magnetic tape after vacuum heating the magnetic tape is greater than 0 nm but less than or equal to 10.0 nm; and
a difference, Safter−
Sbefore, between a spacing Safter measured by optical interferometry on the surface on the backcoat layer side of the magnetic tape after vacuum heating the magnetic tape and a spacing Sbefore, measured by optical interferometry on the surface on the backcoat layer side of the magnetic tape before vacuum heating the magnetic tape is greater than 0 nm but less than or equal to 8.0 nm.
1 Assignment
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Accused Products
Abstract
The magnetic tape has a magnetic layer and a backcoat layer, wherein the Ra on the magnetic layer side surface is less than or equal to 1.8 nm, the coefficient of friction measured on the base portion of the magnetic layer side surface is less than or equal to 0.35, the Ra measured on the backcoat layer side surface is less than or equal to 5.0 nm, the backcoat layer contains a fatty acid ester, the FWHMbefore measured on the backcoat layer side surface before vacuum heating is greater than 0 nm but less than or equal to 10.0 nm, the FWHMafter after vacuum heating is greater than 0 nm but less than or equal to 10.0 nm, and the difference between the spacing measured on the backcoat layer side surface after and before vacuum heating is greater than 0 nm but less than or equal to 8.0 nm.
117 Citations
19 Claims
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1. A magnetic tape,
which comprises, on one surface of a nonmagnetic support, a magnetic layer comprising ferromagnetic powder and binder, and on the other surface of the nonmagnetic support, a backcoat layer comprising nonmagnetic powder and binder, wherein: -
a centerline average surface roughness Ra on a surface on the magnetic layer side of the magnetic tape is less than or equal to 1.8 nm; a coefficient of friction measured on a base portion of the surface on the magnetic layer side of the magnetic tape is less than or equal to 0.35; a centerline average surface roughness Ra measured on a surface on the backcoat layer side of the magnetic tape is less than or equal to 5.0 nm; the backcoat layer comprises a fatty acid ester, a full width at half maximum of a spacing distribution measured by optical interferometry on the surface on the backcoat layer side of the magnetic tape before vacuum heating the magnetic tape is greater than 0 nm but less than or equal to 10.0 nm; a full width at half maximum of a spacing distribution measured by optical interferometry on the surface on the backcoat layer side of the magnetic tape after vacuum heating the magnetic tape is greater than 0 nm but less than or equal to 10.0 nm; and a difference, Safter−
Sbefore, between a spacing Safter measured by optical interferometry on the surface on the backcoat layer side of the magnetic tape after vacuum heating the magnetic tape and a spacing Sbefore, measured by optical interferometry on the surface on the backcoat layer side of the magnetic tape before vacuum heating the magnetic tape is greater than 0 nm but less than or equal to 8.0 nm. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9)
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10. A method of manufacturing a magnetic tape,
wherein the magnetic tape is a magnetic tape which comprises, on one surface of a nonmagnetic support, a magnetic layer comprising ferromagnetic powder and binder, and on the other surface of the nonmagnetic support, a backcoat layer comprising nonmagnetic powder and binder, wherein: -
a centerline average surface roughness Ra on a surface on the magnetic layer side of the magnetic tape is less than or equal to 1.8 nm; a coefficient of friction measured on a base portion of the surface on the magnetic layer side of the magnetic tape is less than or equal to 0.35; a centerline average surface roughness Ra measured on a surface on the backcoat layer side of the magnetic tape is less than or equal to 5.0 nm; a full width at half maximum of a spacing distribution measured by optical interferometry on the surface on the backcoat layer side of the magnetic tape before vacuum heating the magnetic tape is greater than 0 nm but less than or equal to 10.0 nm; a full width at half maximum of a spacing distribution measured by optical interferometry on the surface on the backcoat layer side of the magnetic tape after vacuum heating the magnetic tape is greater than 0 nm but less than or equal to 10.0 nm; and a difference, Safter−
Sbefore, between a spacing Safter measured by optical interferometry on the surface on the backcoat layer side of the magnetic tape after vacuum heating the magnetic tape and a spacing Sbefore measured by optical interferometry on the surface on the backcoat layer side of the magnetic tape before vacuum heating the magnetic tape is greater than 0 nm but less than or equal to 8.0 nm; andthe method comprises; coating and drying a backcoat layer-forming composition comprising nonmagnetic powder, binder, and a fatty acid ester on one surface of a nonmagnetic support to form a coating layer; and applying vibration to the coating layer that has been formed to form a backcoat layer. - View Dependent Claims (11, 12, 13, 14, 15, 16, 17, 18, 19)
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Specification