Magnetic Tape Backcoat Surface Roughness and Friction Control
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Solution Overview
Problem
Magnetic tapes face challenges in achieving high electromagnetic characteristics and preventing dropout and edge damage, with increased smoothness on the backcoat layer side leading to winding misalignment and edge damage during use.
Innovation Solution
A magnetic tape with a magnetic layer and a backcoat layer, where the magnetic layer side has a centerline average surface roughness of ≤1.8 nm and a coefficient of friction ≤0.35, and the backcoat layer contains a fatty acid ester, with specific surface roughness and friction characteristics to inhibit dropout and edge damage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the smoothness of the backcoat layer surface is increased to inhibit dropout, then dropout is reduced, but winding misalignment and edge damage occur
Solution Approach 1:
The patent applies different surface roughness characteristics to different locations on the tape. The center portion of the backcoat layer surface has Ra ≤ 5.0 nm to prevent dropout, while the edge portions have controlled roughness and friction coefficients to prevent winding misalignment and edge damage. This local differentiation resolves the contradiction between dropout prevention and winding stability.
Solution Approach 2:
The patent changes the surface roughness parameter (Ra) and friction coefficient parameters at different locations of the backcoat layer. By controlling Ra ≤ 5.0 nm at the center and μ ≤ 0.50 at edges, the patent optimizes both dropout prevention and winding alignment, transforming the single-parameter optimization into a multi-parameter spatial distribution solution.
2Reliability
If the smoothness of the magnetic layer surface is increased to enhance electromagnetic characteristics, then electromagnetic performance is improved, but surface protrusions may form causing reverse transfer
Solution Approach 1:
The patent applies different surface roughness characteristics to different locations on the magnetic layer. The center portion has Ra ≤ 1.8 nm for optimal electromagnetic characteristics, while the edge portions have controlled friction coefficients (μ ≤ 0.35) to prevent reverse transfer. This spatial differentiation resolves the contradiction between electromagnetic performance and reverse transfer prevention.
Solution Approach 2:
The patent uses composite material structures with binder and ferromagnetic powder in the magnetic layer, and binder with nonmagnetic powder and fatty acid ester in the backcoat layer. This composite structure allows independent optimization of electromagnetic characteristics and surface friction properties, resolving the contradiction between signal quality and reverse transfer prevention.
3Reliability
If the friction coefficient on the magnetic layer surface is decreased to improve signal reading, then signal reading stability is enhanced, but edge damage may increase during winding
Solution Approach 1:
The patent applies different friction coefficient characteristics to different locations. The center portion of the magnetic layer has μ ≤ 0.35 for stable signal reading, while the edge portions of the backcoat layer have controlled roughness and friction to prevent edge damage during winding operations. This local differentiation resolves the contradiction between signal reading and edge protection.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The magnetic tape exhibits good electromagnetic characteristics, reduces dropout, and minimizes edge damage during use by controlling the surface roughness and friction on both sides, ensuring stable signal reading and extended tape life.
Implementation Method 1
the backcoat layer contains a fatty acid ester
Implementation Method 2
the centerline average surface roughness Ra on the surface on the magnetic layer side of the magnetic tape is less than or equal to 1.8 nm; the centerline average surface roughness Ra measured on the surface on the backcoat layer side of the magnetic tape is less than or equal to 5.0 nm
Implementation Method 3
a magnetic layer containing ferromagnetic powder and binder
Data Source
AI summary
The magnetic tape has a magnetic layer and a backcoat layer. 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, and 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. In addition, 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.