Magnetic Recording Medium Support Viscosity and Coating
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Solution Overview
Problem
High-density magnetic recording media face challenges in achieving both high output and durability due to issues with thinning non-magnetic supports, which lead to reduced durability, increased dropout, and error rates, as well as the limitations of using fillers and undercoat layers in suppressing surface influences of the non-magnetic support.
Innovation Solution
A magnetic recording medium is developed with a non-magnetic support having intrinsic viscosity between 0.47 to 0.51 dL/g, coated with a first and second radiation curable resin layer on both surfaces, and a magnetic layer on one surface, with specific surface roughness and filler thickness to enhance durability and output.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If the thickness of non-magnetic support is reduced to increase volume density, then recording density is improved, but durability of the non-magnetic support is lowered
Solution Approach 1:
The patent changes the intrinsic viscosity parameter of the non-magnetic support from conventional values to specifically 0.45-0.55 dL/g, and controls the thickness within 3-10 μm. This parameter optimization allows the thin support to maintain sufficient mechanical strength and durability while achieving high volume density for high-density recording.
Solution Approach 2:
The patent creates a composite structure by combining the non-magnetic support with a magnetic layer containing ferromagnetic powder and binder. This composite construction enhances the overall durability of the thin support system while maintaining the required recording properties.
2Quantity of substance
If the magnetic layer is made thin to increase recording density, then volume density is improved, but output is lowered and dropout increases due to insufficient leveling effect
Solution Approach 1:
The patent optimizes the thickness of the magnetic layer to 0.5-5.0 μm and controls the surface roughness to 0.01-0.1 μm. By precisely controlling these parameters, the thin magnetic layer achieves sufficient leveling effect to suppress surface influences from the non-magnetic support, preventing dropout while maintaining high recording density and adequate output.
Solution Approach 2:
The patent applies different quality requirements to different parts of the magnetic layer: the bulk thickness is optimized for high-density recording (0.5-5.0 μm), while the surface quality is specifically controlled for smoothness (surface roughness 0.01-0.1 μm) to ensure good contact with the magnetic head and prevent dropout. This local differentiation of properties resolves the contradiction between thinness and output.
3Manufacturing precision
If fillers are added to non-magnetic support to suppress surface influences, then surface state is improved, but characteristics of the non-magnetic support are largely changed and durability is compromised
Solution Approach 1:
Instead of adding fillers that alter the support's characteristics, the patent changes the intrinsic viscosity parameter of the non-magnetic support to 0.45-0.55 dL/g and controls its thickness to 3-10 μm. This parameter-based approach achieves the desired surface state and durability without the harmful effects of filler addition.
Solution Approach 2:
The patent extracts the filler addition approach and replaces it with intrinsic property control of the non-magnetic support material itself. By optimizing the support's viscosity and thickness parameters directly, the patent achieves surface influence suppression without introducing foreign substances that would compromise durability.
4Manufacturing precision
If undercoat layer is added between non-magnetic support and magnetic layer to suppress surface influences, then surface state is improved, but rigidity of the medium is lowered and durability is deteriorated
Solution Approach 1:
The patent achieves surface state improvement by optimizing the intrinsic viscosity of the non-magnetic support to 0.45-0.55 dL/g and controlling its thickness to 3-10 μm, eliminating the need for an undercoat layer. This direct parameter control maintains the rigidity and durability of the support while achieving the desired surface quality.
Solution Approach 2:
The patent removes the undercoat layer entirely and replaces its function with optimized parameters of the non-magnetic support itself. By controlling the support's viscosity and thickness, the patent achieves surface influence suppression without the rigidity-damaging effect of an additional layer.
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 solution provides a high-density magnetic recording medium with improved durability and output by effectively suppressing surface influences of the non-magnetic support and maintaining structural integrity, thereby reducing dropout and error rates.
Implementation Method 1
a first radiation curable resin layer on one surface of the non-magnetic support, and a second radiation curable resin layer on the other surface of the non-magnetic support
Data Source
AI summary
A magnetic recording medium comprising: a magnetic layer; a first radiation curable resin layer; a non-magnetic support having an intrinsic viscosity of from 0.47 to 0.51 dL/g; and a second radiation curable resin layer, in this order, wherein the first radiation curable resin layer contains a filler, and the second radiation curable resin layer contains a filler.