JPS61105726A - Rigid magnetic disk - Google Patents

Abstract

PURPOSE:To improve the adhesiveness between a plate-shaped body and magnetic layer by coating a resin onto the surface of the plate-shaped body to 5-500mum thickness then providing the magnetic layer consisting of magnetic particles and plastic thereon. CONSTITUTION:The surface of the plate-shaped body consisting of a metallic plate, etc. is subjected to a primer treatment with a resin having 5-500mum thickness and the magnetic layer consisting of magnetic particles and plastic is provided thereon. The adhesiveness between the plate-shaped body and the magnetic layer and the thickness accuracy are thus improved. The effect of the pretreatment is low if the pretreatment thickness is <=5mum and the thickness accuracy of a disk is poor if <=500mum. The adhesiveness is thus improved and the disk suitable for a rigid magnetic disk is obtd.

Description

[Detailed description of the invention] The present invention relates to a rigid magnetic disk provided with a magnetic layer comprising:

[Prior Art] Rigid magnetic disks are seen as promising as backup memory for computers in terms of cost and capacity, and are being put into practical use. Currently, M plates are mainly used as substrates for rigid magnetic disks, and a magnetic film is formed on the surface of an Al plate to make rigid magnetic disks thinner and thinner.
A gap of about 2 Am or less is required. Therefore, one of the characteristics of the disk substrate is that
Low roughness is required for all 4i, -7,
Polishing the Al plate requires a large amount of man-hours, making the substrate extremely expensive compared to the material cost of the Al plate. As a method of making an inexpensive board, a metal plate is used as a reinforcing material, and a mirror [
] It is thought that the machine structure board will be made into a single piece of plastic using a mold that supports II, or in other words, plastic-metal. , cooling, thermal shock, high temperature and high humidity, etc. Therefore, a peeling phenomenon occurred between the plastic and gold JI4, which have different coefficients of thermal expansion.

[Purpose of the invention]

In order to completely improve these shortcomings, pot metal plates, ceramic plates,
There is a method of pre-treating different surfaces of a plate-shaped body such as a glass plate with a resin (hereinafter referred to as primer treatment), but in the present invention, after priming the plate-shaped body to a thickness of 5 to 500 μm, The inventors have discovered that if a magnetic layer made of magnetic particles and plastic is formed thereon, a rigid magnetic disk made of a plate-like material and a magnetic layer with good lamination properties can be obtained, leading to the present invention.

[Structure of the Invention] The present invention provides a magnetic disk in which a magnetic layer made of magnetic particles and plastic is provided on a plate-shaped body such as a metal plate, and a primer having a thickness of 5 to 500 μm is applied to the surface of the plate-shaped body. The present invention relates to a rigid magnetic disk characterized by the presence of a processing resin which is poisonous. If the thickness of the brimer treatment is 5 μm or less, the effect of the brimer treatment is small, for example, if the storage conditions during air transportation (-50 to 1
0'O), a phenomenon occurs in which the magnetic layer and the plate-like body separate. Further, if the thickness is more than 500 μm, the accuracy of the thickness tends to deteriorate in the dimension after heat treatment of the disk, 7I'li. Furthermore, the thickness of this primer treatment resin is preferably 10 to 508 m. In this range, the effect of compaction between the magnetic layer and the plate-like body is particularly excellent, and the thickness accuracy of the obtained disk is also particularly good. The method of brimer treatment is not particularly limited, but can be treated by spraying, coating with a spinner, or the like. Further, the resin used for the brimer treatment should be flexible, and urethane resins and epoxy resins are suitable.

〔Effect of the invention〕

Since the magnetic disk of the present invention has excellent lamination properties between the magnetic layer and the plate-like body, there is no problem in the process of manufacturing a rigid magnetic disk. Conditions for use as a disk: It is suitable as a rigid magnetic disk since it can sufficiently satisfy the storage conditions.

〔Example〕

An M plate having an outer diameter of 1801 LI+1, an inner diameter of 40 mm, and a thickness of 1.5 μm was used as the plate-shaped body in the example. After washing this Al plate with a seedling agent, the entire surface of the tkl B- plate was coated with a urethane-based brimer treatment resin to a thickness of about 50 μm using a spinner. The coated Ad@ was heated for 186'oi to harden the resin for brimer treatment, and then placed in a casting mold with a mirror surface 1r: 2g of resin containing 80% by weight of r-Fe20'3 particles. A magnetic disk having an outer diameter of 180171 mm, an inner diameter of 401 mm, and a thickness of 1.8 mm and having thin magnetic layers (thickness: about 100 μ77!) on both sides was obtained by casting with epoxy resin.

Comparative Example ■ A magnetic disk was obtained in the same manner as in Example, except that the thickness of the resin for brimer treatment was approximately 8 μm.

Comparative Example 2 A magnetic disk was prepared in the same manner as in Example, except that the thickness of the resin for brimer treatment was set to about 1111 mm.

Next, the thickness (measured at 4 locations) and heat resistance of the magnetic disk 8 on the valley side were measured.The results were as follows.

Machibashi customer entry Sumitomo Bakelite Co., Ltd.

Claims (1)

[Claims] A magnetic disk in which a magnetic layer made of magnetic particles and plastic is provided on a plate-shaped body such as a metal plate, characterized in that a pretreatment resin with a thickness of 5 to 500 μm is present on the surface of the plate-shaped body. Rigid magnetic disk.