JPH07161164A - Disc cartridge - Google Patents

Abstract

PURPOSE:To obtain a disc cartridge which maintains a bonding strength high between a hub and a medium even under high temperatures and also displays a high bonding strength to a metallic surface of the hub. CONSTITUTION:A magnetic disc 7 consisting of a magnetic recording medium 12 and a hub 10 set at a center of the medium is accommodated within a main body of the cartridge in a rotatable fashiorn. A hot-melt adhesive of an urethane series set by moisture and containing 10-60wt.% of polyalkylene glycol is used to bond the hub 10 and medium 12.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a disk cartridge, and more particularly to a disk cartridge in which a magnetic disk is rotatably housed in a cartridge body.

[0002]

2. Description of the Related Art A magnetic disk of a disk cartridge comprises a medium and a hub. The medium is a flexible resin film, and a magnetic recording material is fixed to the surface of the resin film via a binder or the like. The hub is attached to the center of the doughnut-shaped medium, has a fitting hole for fitting with the spindle shaft of the apparatus, and is generally formed of metal or hard plastic. Further, in assembling the magnetic disk, a double-sided adhesive film such as an acrylic type, which is conventionally called an A ring, is used for adhesion between the hub and the medium in consideration of the ease of the manufacturing process, or a rubber hot melt is used. I used to use glue.

[0003]

However, in the conventional magnetic disk cartridge, when the magnetic disk is placed in a high temperature environment or is used in a high temperature environment, the adhesive force between the hub and the medium is lowered. , There was a risk of causing a gap between the two. Further, although the reactive adhesive is not easily affected by the environment, when it is used alone, the adhesiveness to the metal (hub or the like) may be poor and the adhesive strength may be lowered. Therefore, an object of the present invention is to provide a disc cartridge in which the adhesive strength between the hub and the medium is maintained high even in a high temperature environment and the adhesive strength with the metal hub surface is also high.

[0004]

DISCLOSURE OF THE INVENTION According to the present invention, in a disk cartridge in which a magnetic disk composed of a magnetic recording medium and a hub mounted at the center of the medium is rotatably housed in a cartridge body, polyalkylene glycols of 10 to 10 are used. The above object is achieved by providing a disk cartridge characterized in that the hub and the medium are adhered by a moisture-curable urethane hot melt adhesive containing 60 wt%.

[0005]

[Function] The moisture-curable urethane hot melt adhesive causes a chemical secondary bond with the active hydrogen on the surface of the media and the hub. As a result, the media and the hub have a high adhesive strength and high temperature. The adhesive strength of. In addition to the moisture-curable urethane hot melt adhesive, by containing 10 to 60 wt% of polyalkylene glycol, particularly polypropylene glycol having a predetermined average molecular weight, the adhesive interposed between the hub and the medium is sufficiently It becomes a high molecular weight component, and it becomes possible to have stable and sufficient adhesive strength between them, especially between them and the metal hub, regardless of the environmental conditions. Therefore, the adhesive strength of the disk cartridge is high, and the adhesive strength at high temperature is also high, so that reading and writing defects do not occur even in a bad environment of high temperature.

[0006]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of a disk cartridge according to the present invention will be described below with reference to the drawings. FIG. 1 is a perspective view of a disk cartridge according to the present invention, and FIG. 2 is a sectional view of the magnetic disk of FIG. As shown in FIGS. 1 and 2, in the disk cartridge according to the present invention, a magnetic disk 7 including a magnetic recording medium 12 and a hub 10 attached to the center of the medium 12 is rotatably housed in a cartridge body 1. The same as in the conventional magnetic disk cartridge. Therefore, the disc cartridge according to the present invention is provided with the hub 10 and the medium 1.
2 is bonded with a moisture-curable urethane-based hot melt adhesive 14.

The disk cartridge according to the present invention will be further described. As shown in FIGS. 1 and 2, the cartridge body 1 comprises an upper shell 2 and a lower shell 3, and a magnetic disk 7 is rotatably housed therein. . A slide shutter 5 is provided so as to sandwich the upper shell 2 and the lower shell 3, and a window 6 is formed in the shutter 5. Magnetic disk 7
Contacts the head on the device side through the window 6. A circular opening (not shown) through which the spindle shaft of the device is inserted is formed in the center of the lower shell 3, and the spindle shaft fits into the hub 10 hole of the magnetic disk 7 during loading, The magnetic disk 7 is rotated.

The hub 10 of the magnetic disk 7 is formed by punching a metal plate or hard plastic, and the hub 10 here is formed by a metal plate.
The medium 12 is composed of a flexible plastic sheet known per se, and a magnetic recording material fixed to a desired area on the sheet surface. The hub 10 and the medium 12 are fixed to each other via an adhesive 14, and the adhesive 14 is a moisture-curable urethane hot-melt adhesive. A moisture-curable urethane hot melt adhesive is one in which an NCO-terminated polymer reacts with moisture in the air or an appropriate curing agent to cure. Such an adhesive is not only hardened by heating, but also has a reactivity at room temperature, so that an adhesive operation is easy and workability is excellent.

In the moisture-curable urethane-based hot melt adhesive, polyalkylene glycol is contained in an amount of 10-6.
It is contained in an amount of 0 wt%, particularly preferably in the range of 30 to 50 wt%. In such a range, the moisture-curing reaction of the hot-melt adhesive sufficiently progresses and the molecular weight thereof is increased, so that the adhesive strength between the hub 10 and the medium 12 is enhanced. Further, when the polyalkylene glycol exceeds 60 wt%, the moisture curing reaction of the adhesive is suppressed, the reactive high molecular weight component is decreased, and the compatibility with the urethane adhesive is deteriorated. If it is less than 10 wt%, the adhesive strength is lowered, which is not preferable. As the polyalkylene glycol, those having lower alkylene have general versatility, and examples thereof include polyethylene glycol and polypropylene glycol, and polypropylene glycol is particularly preferable. Moreover, the average molecular weight of the polyalkylene glycol is preferably in the range of 500 to 20,000, particularly preferably in the range of 2,000 to 15,000.

The adhesive strength after curing of the hub 10 and the medium 12 with such a moisture-curable urethane hot melt adhesive is 800 g at a temperature of 23 ° C. to 60 ° C.
Above, especially 1000 g or more is desirable. It is easy to load 60 when loading the magnetic disk cartridge in the device.
Although the temperature may reach 0 ° C., the magnetic disk 7 does not have a bad environmental condition, that is, a gap between the hub and the medium does not occur if the adhesive strength is within the above range. The adhesive strength is vertical peel strength.

The disk cartridge having such a structure is used for the hub 10 of the magnetic disk 7, especially the metal hub 1.
Since the adhesive strength between 0 and the medium 12 at the initial stage and at high temperature is high, there are few assembly defects and the heat resistance is also excellent.

An evaluation experiment of the adhesive strength between the hub and the medium of the magnetic disk used in this embodiment and the conventional magnetic disk will be shown below. Example 1 10 mg of a moisture-curable urethane-based hot melt adhesive containing 40 wt% of polypropylene glycol having a number average molecular weight of 5000 (hereinafter referred to as PPG) was applied between the hub and the medium (applied area: about 1.0 cm ² ) And glue them together, and at a temperature of 23 ° C and a humidity of 50% RH for 24 hours.
After standing for 24 hours in each of the environments shown in Table 1, the vertical peel strength of each was measured. The results are shown in Table 1.

Comparative Example 1-A hub and a medium were bonded in the same manner as in Example 1 except that a moisture-curable urethane hot melt adhesive containing no PPG was used. Further, the vertical peel strength was measured under the same environment as in Example 1. The results are shown in Table 1. Comparative Example 2-A hub and a medium were adhered in the same manner as in Example 1 except that a moisture-curable urethane hot melt adhesive containing 5 wt% of PPG was used. Further, the vertical peel strength was measured under the same environment as in Example 1. The results are shown in Table 1. Comparative Example 3 Example 1 except that a moisture-curable urethane hot melt adhesive containing 70 wt% of PPG was used.
The hub and media were glued in the same way as. Further, the vertical peel strength was measured under the same environment as in Example 1. The results are shown in Table 1.

[0014]

[Table 1]

[0015]

The disk cartridge according to the present invention is
The adhesive strength between the hub and the medium is kept high even in a high temperature environment, and the adhesive strength with the metal hub surface is also increased.

[Brief description of drawings]

FIG. 1 is a perspective view of a magnetic disk cartridge according to the present invention.

2 is a cross-sectional view of the magnetic disk of FIG.

[Explanation of symbols]

 1 Cartridge Main Body 2 Upper Shell 3 Lower Shell 5 Shutter 6 Window 7 Magnetic Disk 10 Hub 12 Media 14 Moisture Curing Urethane Hot Melt Adhesive

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Kukei Oshima 2606 Akabane, Kaigai-cho, Haga-gun, Tochigi Prefecture Kao Co., Ltd.

Claims (1)

[Claims] 1. A disk cartridge in which a magnetic disk comprising a magnetic recording medium and a hub attached to the center of the medium is rotatably housed in a cartridge body, wherein a moisture curing type containing 10 to 60 wt% of polyalkylene glycol. A disc cartridge, characterized in that the hub and the medium are adhered with a urethane-based hot melt adhesive.