JP2690785B2 - Magnetic disk body - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a magnetic disk unit housed in a disk cartridge, and more particularly to a magnetic disk unit characterized by an adhesive for bonding a hub and a magnetic disk. .

[Conventional technology]

As conventional magnetic disk bodies, those described in Japanese Utility Model Application Laid-Open No. 61-86870 and Japanese Patent Application Laid-Open No. 63-69081 are known.

The magnetic disk described in JP-A-61-86870 is
By disposing the flange portion of the hub and the inner peripheral portion of the magnetic disk via a synthetic resin band arranged over the entire periphery of the flange portion, distortion generated from the bonded portion is reduced.

Further, the magnetic disk described in Japanese Patent Application Laid-Open No. 63-69081 discloses a method in which an adhesive colored in a color different from the color of the flange is applied to the flange of the hub to detect the application state of the adhesive. This facilitates adhesion between the flange portion of the hub and the inner peripheral portion of the magnetic disk to reduce the occurrence of defective products.

In addition to the above-mentioned magnetic disk body, there is also known a magnetic disk body in which the flange portion of the hub is bonded to the flange portion of the hub with a double-sided adhesive ring, and then the inner peripheral portion of the magnetic disk is bonded to the flange portion of the hub. ing.

[Problems to be solved by the invention]

However, Japanese Utility Model Laid-Open Publication No.
-69081, each magnetic disk body uses an adhesive such as alkyl acrylate, the adhesive lacks stability at the time of supply, poor workability when supplying the adhesive, etc. It was not preferable in the process. Further, although the adhesive has a large humidity expansion, the hub made of metal or the like does not have a humidity expansion, so that a difference in expansion amount between the hub and the magnetic disk at these bonded portions causes a deformation of the magnetic disk. There was fear.

In addition, the magnetic disk body bonded using the double-sided adhesive ring has a control paper and a release paper on both sides of the double-sided adhesive ring before use. The paper must be peeled off, complicating the bonding process. In addition, the double-sided pressure-sensitive adhesive ring has a problem that the yield is low and the cost is high because a base material such as a nonwoven fabric or PET is required. Further, while the magnetic disk body repeatedly changes its temperature between a high temperature and a low temperature, the creep characteristic of the double-sided adhesive ring at a high temperature is deteriorated, and the magnetic disk is displaced at the flange portion of the hub. Was.

Therefore, the applicant of the present invention has previously disclosed in Japanese Patent Application No. 1-146300 a magnetic disk body that solves the above-mentioned problems, that is, a hub and a magnetic disk are bonded to each other by a non-solvent type two-component curing type urethane adhesive Proposed magnetic disk body. However, in the case of the magnetic disk body, the mixing ratio of the two liquids has a great influence on the adhesive strength, and in order to obtain a reliable product, 2
It was necessary to strictly control the mixing ratio of the liquid.

Therefore, the object of the present invention is to allow a wide range of admixture ratio of the adhesive when the magnetic disk and the hub are bonded together to form a magnetic disk body, and to improve the convenience of the operation of supplying the adhesive. (EN) Provided is a magnetic disk body which can be used and whose adhesive agent after bonding is stable against temperature and humidity.

[Means for solving the problem]

The present inventors have conducted various studies on adhesives that are stable at the time of supply and stable against temperature and humidity after bonding and are not significantly affected by the mixing ratio of the two liquids, and as a result, the specific 2 It has been found that the above problems can be solved by using a liquid-curable adhesive.

The present invention has been made based on the above findings, and in a magnetic disk body including a hub having a flange portion and a magnetic disk adhered to the flange portion of the hub at an inner peripheral portion thereof, the flange portion and the A magnetic disk body characterized by being bonded to an inner peripheral portion by a non-solvent acrylic adhesive containing an oxidation catalyst and a reduction catalyst and being cured by an oxidation-reduction reaction of these catalysts. is there.

The acrylic adhesive used in the magnetic disk body of the present invention is mainly composed of an acrylic compound. As the acrylic compound, for example, acrylic modified compounds such as epoxy acrylate, polyester acrylate, urethane acrylate are preferably used.
When the acrylic compound is used as the acrylic adhesive, ethyl methacrylate, methacrylic acid-2-
It is used by dissolving it in a methacrylic acid ester such as ethylhexyl or an acrylic compound such as methyl acrylate.

The acrylic adhesive is the acrylic compound containing an oxidation catalyst and a reduction catalyst. The acrylic adhesive can be used as a one-component type or a two-component type, and when it is used as a two-component type, a solution containing the acrylic compound as a main component is used as a first liquid and a second liquid. Separated into a liquid, the first liquid contains the oxidation catalyst, and the second liquid contains the reduction catalyst, and the first liquid and the second liquid form the acrylic adhesive.

The oxidation catalyst causes a redox reaction by causing a redox reaction in the acrylic adhesive in the coexistence of the reduction catalyst to serve as a polymerization initiator of the acrylic compound. In other words, unless the both catalysts coexist, the acrylic adhesive does not polymerize or cure.

As the oxidation catalyst, for example, organic peroxides such as methyl ethyl ketone peroxide and benzoyl peroxide are preferably used, and the reduction catalyst in the presence of the oxidation catalyst includes reduction of cobalt naphthenate, dimethylaniline and the like. A sex compound is preferably used.

As described above, the oxidation catalyst and the reduction catalyst are
Liquid 2 and 2nd liquid are separately contained to prepare 2 liquids,
It is preferably used as a two-component type adhesive.

Further, the first liquid containing the oxidation catalyst and the second liquid containing the reduction catalyst each further contain an elastomer such as butadiene rubber or natural rubber to make the acrylic adhesive resistant to impact. It is possible to impart sex.

Thus, in order to prepare the first liquid, it is preferable to add 0.02 to 10 parts by weight of the oxidation catalyst to 100 parts by weight of the acrylic compound. Further, in order to prepare the second liquid, a reducing catalyst was added to 0.0 per 100 parts by weight of the acrylic compound.
It is preferable to contain 2 to 10 parts by weight.

Further, in order to prepare the first liquid and the second liquid, it is preferable to add 10 to 60 parts by weight of the elastomer to 100 parts by weight of the acrylic compound.

Further, the adhesive used for the magnetic disk body of the present invention may be a one-component type in addition to the above-mentioned two-component type, and in the case of the one-component type, a solution containing the acrylic compound. The above-mentioned oxidation catalyst and the above-mentioned reduction catalyst may be added and used immediately before use.

When the above-mentioned acrylic adhesive used for the magnetic disk body of the present invention is of a two-liquid type, even if the mixing ratio of the first liquid and the second liquid is changed, the first liquid and the second liquid are respectively The contained oxidation catalyst and reduction catalyst act effectively, the peroxide which is the oxidation catalyst is cleaved to generate free radicals, and serves as a polymerization initiator of the acrylic compound, and the first liquid and the second liquid. It is possible to polymerize and cure the respective acrylic compounds and elastomers, and it is significantly suppressed that they are influenced by the mixing ratio of the first liquid and the second liquid.

Moreover, the oxidation catalyst and the reduction catalyst are individually
Since it is contained in the liquid and the second liquid, the first liquid and the second liquid are stable, respectively, and the supply work in the manufacturing process of the magnetic disk body is stabilized and the convenience is improved. Moreover, the cured adhesive is stable against temperature and humidity and has excellent weather resistance.

〔Example〕

Hereinafter, the magnetic disk of the present invention will be described based on the embodiment shown in FIGS. 1, 2 and 3. In each figure,
FIG. 1 is a plan view showing a magnetic disk cartridge, and FIG.
FIG. 3 is a plan view showing the magnetic disk unit taken out from the magnetic disk cartridge, and FIG. 3 is a diagram showing a state in which the magnetic disk is pressed against the hub of the magnetic disk unit of the present invention and the two are bonded together. FIG. 3 is a partially enlarged view corresponding to a cross section taken along a line III.

The magnetic disk unit 1 of the present embodiment is composed of a hub 11 and a magnetic disk 12 adhered to the hub 11 by an acrylic adhesive (hereinafter referred to as “adhesive”) used in the present invention. As shown in the figure, the magnetic disk jacket 2 is rotatably housed and used for recording and reproduction.

As shown in FIG. 2, the hub 11 has a flange portion 11 around its periphery.
A is formed, and the inner peripheral portion 12A of the magnetic disk 12 is adhered to the flange portion 11A by the adhesive as described above.

Thus, in order to bond the hub 11 and the magnetic disk 12 with the adhesive, as shown in FIG.
Inner peripheral portion 1 of the magnetic disk 12 in the flange portion 11A of
Apply the first liquid 3A over the entire circumference of the side that abuts 2A, and
After applying the second liquid 3B over the entire circumference of the inner peripheral portion 12A of the magnetic disk 12 that contacts the flange portion 11A, the inner peripheral portion of the magnetic disk 12 is located at the flange portion 11A of the hub 11. Approximately 2 kg / cm ² at room temperature according to the position of 12 A
Press for a few seconds with the pressure. In the meantime, the first liquid 3A and the second liquid 3B react with each other to generate an acrylic resin, and the hub 11 and the magnetic disk 12 adhere to each other. In addition, upon adhesion, for example, ethyl methacrylate is used as the acrylic compound of each of the first liquid 3A and the second liquid 3B, and butadiene rubber is used as the elastomer, and the oxidation catalyst contained in the first liquid 3A is used. Is used as methyl ethyl ketone peroxide, and cobalt naphthenate is used as the reducing catalyst contained in the second liquid 3B. It is preferable that the first liquid 3A and the second liquid 3B be applied in approximately equal amounts, specifically, about 1 mg each.

Both the first liquid 3A and the second liquid 3B, which are two-component curing type adhesives used for the magnetic disk body 1 of the present embodiment, do not contain a solvent and are stable for a long time, so that the supplying operation is not performed. The respective liquids 3A and 3B can be easily supplied at this time, the workability of the adhesion can be improved, and since the solvent is not contained as described above, the drying equipment is unnecessary and the equipment can be simplified.

The cured adhesive 3 is stable to temperature and humidity at high temperature and high humidity, expands and does not easily swell, and the creep characteristics at high temperature are not easily deteriorated. The positional deviation of the magnetic disk 12 is extremely small, and the magnetic disk body 1 capable of stable recording and reproducing can be obtained.

In the above embodiment, the first liquid 3A is applied to the flange portion of the hub 11.
Although the case in which the second liquid 3B is applied to the inner peripheral portion 12A of the magnetic disk 12 on the magnetic disk 12 has been described above, the magnetic disk body of the present invention is applied to the first liquid 3A and the second liquid 3B in the above embodiment. And the first liquid 3A is transferred to the inner peripheral portion of the magnetic disk 12.
It is obvious that the second liquid 3B may be applied to the flange portion 11A of the hub 11 on 12A.

Alternatively, the first liquid 3A and the second liquid 3B may be applied to either a magnetic disk or a hub in a superimposed manner.

〔The invention's effect〕

The magnetic disk body of the present invention has a wide admissible range of the mixing ratio of the adhesive when the magnetic disk and the hub are bonded to each other to form the magnetic disk body, and the convenience of the operation of supplying the adhesive is improved. The magnetic disk body that can be used, and the adhesive after bonding is stable against temperature and humidity.

[Brief description of the drawings]

FIG. 1 is a plan view showing a magnetic disk cartridge, and FIG.
FIG. 3 is a plan view showing the magnetic disk unit taken out from the magnetic disk cartridge, and FIG. 3 is a diagram showing a state in which the magnetic disk is pressed against the hub of the magnetic disk unit of the present invention and the two are bonded together. FIG. 3 is a partially enlarged view of a view corresponding to a cross-sectional view taken along the line III. 1; magnetic disk 3A; first liquid, 3B; second liquid 11; hub, 11A; flange 12; magnetic disk, 12A; inner periphery

Claims (1)

(57) [Claims] 1. A magnetic disk body comprising a hub having a flange portion and a magnetic disk adhered to the flange portion of the hub at an inner peripheral portion thereof, wherein the flange portion and the inner peripheral portion are provided with an oxidation catalyst and A magnetic disk body comprising a non-solvent acrylic adhesive which contains a reducing catalyst and is cured by an oxidation-reduction reaction of these catalysts.