JP2004117700A - Sticky adhesive label for hard disk drive - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a sticky adhesive label for a hard disk drive (HDD) which can be easily peeled off the adhered sticky adhesive label from the HDD. <P>SOLUTION: The adhesive label has an information display section on one surface of a base material and an adhesive layer on the other surface of the base material, and can decrease sounds generated during driving of the HDD, by being adhered on the outside surface of a casing of the HDD. The outermost surface of the adhesive layer is prepared by weak adhesive treatment. It is allowed to a 180 ° peel adhesive force (after contact-bonding to an aluminum plate at a peeling speed of 300 mm/min and at 23°C, stands in a room during two hours at 60°C) be 2-12 N/20 mm. It is preferable that the weak adhesive treatment is weak adhesive treatment for reducing a rate of a polar group of the outermost surface of the adhesive layer, or weak adhesive treatment for curing the outermost surface of the adhesive layer by a cross-linker. <P>COPYRIGHT: (C)2004,JPO

Description

【００６３】
表１から明らかなように、実施例１及び２に係る粘着ラベルは、粘着力が適度な値であり、過度な上昇が抑制されているので、剥離させる際には、容易に剥離させることができる。しかも、剥離した後には、糊残りが生じていない。特に、粘着性を低下させて剥離性を向上させているにもかかわらず、ハードディスクドライブに貼付しても浮きや剥がれが生じず、優れた外観性を保持することができる。さらには、優れた制振特性も保持しており、現在市販されているハードディスクドライブの表示ラベルの貼付部位に貼付するだけで、駆動時発生音を１ｄＢ以上低減することが可能である。
【００６４】
なお、比較例１及び２に係る粘着ラベルは、粘着力が強く、剥離に手間がかかり、しかも、剥離後、ハードディスクドライブの筐体の貼付面に糊残りがみられる場合もある。
【００６５】
【発明の効果】
本発明の粘着ラベルは、上記の如き構成を有することにより、粘着ラベルとしての各種情報表示機能と、ハードディスクドライブの駆動時における発生音を低減できる機能を両立させることでき、しかも、粘着力の過度な上昇が抑制されており、剥離させる際には、容易に剥離させることが可能である。また、貼付した際には、浮きや剥がれが生じず、優れた外観性を保持している。
従って、本発明の粘着ラベルでは、誤って貼り付けた際や、リワークが生じた際などにおいて、粘着剤ラベルの剥離作業を大きく改善することができ、作業効率の向上に寄与することができる。
【図面の簡単な説明】
【図１】本発明のハードディスクドライブ用粘着ラベルの一態様を示す概略断面図である。
【図２】本発明のハードディスクドライブ用粘着ラベルが貼付されたハードディスクドライブを示す概略図である。
【符号の説明】
１　　ハードディスクドライブ用粘着ラベル
２　　基材
２ａ　樹脂フィルム層
２ｂ　金属箔
３　　最表面に弱粘着処理が施されている粘着剤層
４　　情報表示部
Ａ　　ハウジング本体
Ｂ　　トップカバー[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to an adhesive label for a hard disk drive that is used by being attached to an outer surface of a housing of a hard disk drive and that can display various functions as an adhesive label and reduce noise generated when the hard disk drive is driven. The present invention relates to an adhesive label for a hard disk drive, which facilitates a peeling process of an attached adhesive label.
[0002]
[Prior art]
In recent years, demand for hard disk drives for personal computers and other consumer applications has been greatly increased, and accordingly, the miniaturization of the hard disk drive itself and the reduction of noise generated during driving (securing quietness) have led to an increase in storage capacity. Has become an important characteristic along with the increase in
[0003]
As a means for reducing the noise generated when the hard disk drive is driven, it is general to use a damping steel plate for a part (for example, a cover) of the housing of the hard disk drive. However, the method using the vibration-damping steel sheet is still insufficient in size and weight, noise reduction, or productivity and cost of a hard disk drive whose recording disk diameter is 2.5 inches or less. It is not a simple means, and further improvement is required.
[0004]
Therefore, the present inventors have proposed an adhesive label for a hard disk drive (hereinafter, referred to as an “HDD adhesive label”) which can reduce the noise generated when the hard disk drive is driven by being attached to the outer surface of the housing of the hard disk drive. There is a proposal). By using such an HDD adhesive label, it is possible to achieve noise reduction while exhibiting an information display function (see Patent Document 1).
[0005]
[Patent Document 1]
JP 2001-351369A
[0006]
[Problems to be solved by the invention]
However, as the pressure-sensitive adhesive, a pressure-sensitive adhesive having a relatively high glass transition temperature (Tg) is often selected and used, and the pressure-sensitive adhesive of such a relatively high Tg type has a very high adhesive strength, and can be used over time or time. Depending on the day, the adhesive strength may further increase. In actual use, rework may occur after sticking to the hard disk drive and assembling, and at this time, the label needs to be peeled off. If the label has a very high adhesive strength, the peeling step becomes complicated. In addition, when the adhesive remains on the portion of the hard disk drive where the label was affixed, or when the adhesive force is too high, the cover material of the hard disk drive may be deformed. As described above, in the conventional HDD adhesive label, it is difficult to easily peel off the HDD adhesive label once adhered, and there is a problem that the workability of peeling the HDD adhesive label is low.
[0007]
The present invention has been made in view of the above problems, and an object of the present invention is to provide an HDD adhesive label that can be easily peeled when the HDD adhesive label attached to a hard disk drive is peeled. Is to provide.
Another object of the present invention is to suppress the excessive increase in the adhesive force even when using a pressure-sensitive adhesive having excellent vibration damping performance and high adhesiveness, and to easily peel when peeling. To provide a pressure-sensitive adhesive label for an HDD that can be used.
[0008]
[Means for Solving the Problems]
The inventors of the present invention have conducted intensive studies to solve the above problems, and as a result, have various information display functions and attenuated noise generated when the hard disk drive is driven, by attaching the information to an outer surface of a hard disk drive housing. As an adhesive label for HDD with a function that can be used, if the outermost surface of the high-adhesive pressure-sensitive adhesive layer that has excellent vibration-damping properties is subjected to weak adhesive treatment, the excellent vibration-damping properties of the pressure-sensitive adhesive layer will decrease. The present inventors have found that it is possible to suppress the adhesive force from excessively increasing while suppressing or preventing the problem, and to solve the above-mentioned problems, thereby completing the present invention.
[0009]
That is, the present invention has an information display portion on one side of the base material, and has an adhesive layer on the other side, and is attached to the outer surface of the housing of the hard disk drive to generate a sound generated when the hard disk drive is driven. A pressure-sensitive adhesive label for a hard disk drive that can be reduced, wherein a weak pressure-sensitive treatment is applied to an outermost surface of the pressure-sensitive adhesive layer.
[0010]
In the present invention, the 180 ° peel adhesive strength (peeling speed: 300 mm / min, 23 ° C., against an aluminum plate, left at 60 ° C. for 2 hours after pressure bonding) is preferably 2 to 12 N / 20 mm. Further, the weak adhesive treatment may be a weak adhesive treatment for reducing the ratio of polar groups on the outermost surface of the adhesive layer, or a weak adhesive treatment for curing the outermost surface of the adhesive layer with a crosslinking agent.
[0011]
As the base material, a resin film layer may be laminated on both surfaces of a metal foil, and the loss coefficient of the pressure-sensitive adhesive constituting the pressure-sensitive adhesive layer is 0.5 to 5.0 at 20 ° C. There may be.
[0012]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, the present invention will be described with reference to the drawings. FIG. 1 is a schematic sectional view showing one embodiment of the adhesive label for a hard disk drive of the present invention. In FIG. 1, 1 is an adhesive label for a hard disk drive (adhesive label for an HDD), 2 is a substrate, 2a is a resin film layer on the substrate 2, 2b is a metal foil on the substrate 2, and 3 is a weak adhesive treatment on the outermost surface. (Hereinafter, may be referred to as "surface-adhesive-treated pressure-sensitive adhesive layer"), and reference numeral 4 denotes an information display portion of the HDD pressure-sensitive adhesive label 1. FIG. 2 is a schematic view showing a hard disk drive to which the adhesive label for a hard disk drive of the present invention is attached. In FIG. 2, 1 and 4 are the same as those in FIG. 1, and specifically, 1 is an HDD adhesive label, and 4 is an information display section. A is a housing body, and B is a top cover. In FIG. 2, an information display unit is provided on an outer surface of a top cover B of a hard disk drive including a housing main body A in which a recording disk, a magnetic head, a spindle motor, and the like are housed, and a top cover B. 4 is affixed with an HDD adhesive label 1 having an HDD label 4.
[0013]
In the present invention, the HDD adhesive label 1 is attached to the outer surface of the housing of the hard disk drive (for example, the top cover B or the housing body A in FIG. 2) so that the sound generated when the hard disk drive is driven (hereinafter, referred to as “the sound”). It is necessary to be able to reduce the “sound generated during driving”. Here, "can reduce the noise generated during driving of the hard disk drive" means that the noise generated during driving can be reduced (reduced) by 1 dB or more by attaching the HDD adhesive label of the present invention. .
[0014]
In addition, the HDD adhesive label 1 has information display such as “Precautions for use”, “Connection method”, “Recognition / identification items such as product name / manufacturer name” on the surface (back surface) of the base material. It has a part 4. With such a configuration, the function of reducing the noise generated at the time of driving can be added by the adhesive label for HDD which conventionally has only the information display function, and the noise of the hard disk drive can be further reduced. Further, the configuration that has been achieved by the two members of the damping steel plate and the adhesive label can be achieved by the same member.
[0015]
The HDD pressure-sensitive adhesive label 1 of the present invention has the above-described functions, and further requires that the pressure-sensitive adhesive layer of the HDD pressure-sensitive adhesive label be subjected to a weak pressure-sensitive adhesive treatment on the outermost surface. Here, the phrase "the pressure-sensitive adhesive layer of the pressure-sensitive adhesive label for HDD has been subjected to a weak pressure-sensitive treatment on the outermost surface" means that only the outermost surface of the pressure-sensitive adhesive layer has been subjected to the weak pressure-sensitive adhesive treatment, and thus the pressure-sensitive adhesive layer for HDD attached to the hard disk drive. This means that an excessive increase in the adhesive force by the adhesive layer of the HDD adhesive label is suppressed (or weakened) to such an extent that the label can be easily peeled off.
[0016]
In particular, in the present invention, since only the outermost surface of the pressure-sensitive adhesive layer is subjected to the weak pressure-sensitive treatment, a decrease in excellent vibration damping characteristics due to the pressure-sensitive adhesive layer is suppressed or prevented. Therefore, it is possible to maintain a function capable of reducing the noise generated when the HDD is driven, and to exhibit excellent peeling workability.
[0017]
The specific configuration and the like of the HDD pressure-sensitive adhesive label of the present invention are not particularly limited as long as they have the above-mentioned functions and the like, but it is preferable to use the HDD pressure-sensitive adhesive label 1 as shown in FIG. it can. In FIG. 1, an HDD adhesive label 1 has an information display section 4 on one side (back side) of a laminated base material composed of at least three layers in which a resin film layer 2a is laminated on both sides of a metal foil 2b as a base material 2. Is formed, and on the other surface (the surface opposite to the surface on which the information display portion 4 is formed), the pressure-sensitive adhesive layer 3 having the outermost surface subjected to a weak adhesion treatment is formed.
[0018]
[Surface-adhesive treated pressure-sensitive adhesive layer]
The surface weak pressure-sensitive adhesive layer 3 has a configuration in which only the outermost surface of the pressure-sensitive adhesive layer having high adhesiveness is subjected to a weak pressure-sensitive treatment. In the pressure-sensitive adhesive composition forming the surface weak pressure-sensitive adhesive layer 3, as the pressure-sensitive adhesive, a common or known pressure-sensitive adhesive such as a synthetic rubber-based pressure-sensitive adhesive, a natural rubber-based pressure-sensitive adhesive, or an acrylic pressure-sensitive adhesive is appropriately used. Can be selected and used. The adhesives can be used alone or in combination of two or more.
[0019]
As the pressure-sensitive adhesive, an acrylic pressure-sensitive adhesive is preferable from the viewpoint of durability. More specifically, a pressure-sensitive adhesive composed of a polymer (base polymer) containing (meth) acrylate having an alkyl group having 4 to 14 carbon atoms as a main component is desirable. Here, as the (meth) acrylate having an alkyl group having 4 to 14 carbon atoms, for example, butyl group, s-butyl group, t-butyl group, pentyl group, isopentyl group, hexyl group, heptyl group, 2-ethylhexyl Alkyl esters of (meth) acrylic acid having an alkyl group such as a group, an octyl group, an isooctyl group, a nonyl group, an isononyl group, a decyl group, a lauryl group, a myristyl group, an isomyristyl group, and the like.
[0020]
In particular, in the present invention, as the acrylic pressure-sensitive adhesive, a (meth) acrylate having an alkyl group having 7 to 10 carbon atoms, which is compatible with the glass transition temperature and pressure-sensitive properties of the pressure-sensitive adhesive which greatly contributes to vibration damping performance, and acrylic acid An acrylic pressure-sensitive adhesive composed of a polymer having as a copolymer component can be suitably used.
[0021]
The vibration-damping performance of the pressure-sensitive adhesive layer 3 having a weak surface treatment is greatly affected by the glass transition temperature of the pressure-sensitive adhesive, and the characteristics of the pressure-sensitive adhesive layer 3 are controlled by the operating temperature (specifically, the operating temperature of the hard disk drive, which is usually higher than room temperature). In order to exhibit the effect effectively, the loss coefficient of the pressure-sensitive adhesive constituting the pressure-sensitive adhesive layer is usually 0.5 to 5.0 (0.5 to 5.0) at 20 ° C., preferably 0.7 to 5.0. 0.0 or less (0.7 to 5.0). Further, the peak temperature of the loss coefficient of the pressure-sensitive adhesive is preferably -10 ° C or more and 50 ° C or less. By setting the loss coefficient and / or the peak of the loss coefficient of the pressure-sensitive adhesive within the above range, both the vibration damping performance and the pressure-sensitive adhesive property of the pressure-sensitive adhesive can be achieved at an excellent level.
[0022]
Such an adhesive has excellent vibration damping performance, but has high adhesiveness, and the adhesive strength may increase with time due to aging or the like after application. However, in the present invention, only the outermost surface of the pressure-sensitive adhesive layer by the pressure-sensitive adhesive is subjected to a weak pressure-sensitive treatment, whereby an excessive increase in the pressure-sensitive adhesive force is suppressed. As a weak adhesion treatment method applied only to the outermost surface of the pressure-sensitive adhesive layer with such an adhesive, any method capable of weakening only the outermost surface of the pressure-sensitive adhesive layer exhibiting high adhesiveness can be used. The method is not limited, and examples thereof include (1) a weak adhesion treatment method in which the proportion of polar groups on the outermost surface of the pressure-sensitive adhesive layer is reduced, and (2) a weak adhesion treatment method in which the outermost surface of the pressure-sensitive adhesive layer is cured with a crosslinking agent. Can be In addition, the weak adhesion treatment method can be employed alone or in combination of two or more.
[0023]
In the weak adhesion treatment method (1), the ratio of the polar group only on the outermost surface of the pressure-sensitive adhesive layer is reduced to make the outermost surface of the pressure-sensitive adhesive layer low-polarized or non-polarized, so that the HDD having a metal surface is formed. It is possible to suppress or prevent an excessive increase in the adhesive force to the outer surface of the housing. As described above, as a method of reducing the ratio of the polar group on the outermost surface of the pressure-sensitive adhesive layer, for example, a polar group-containing monomer (for example, A method of forming a surface coat layer (sometimes referred to as a “low-polarity surface coat layer”) using a pressure-sensitive adhesive composition having a low content of acrylic acid, methacrylic acid, or the like can be employed.
[0024]
In the polar group-containing monomer component, examples of the polar group include a carboxyl group, a hydroxyl group, a glycidyl group, and the like. In particular, the carboxyl group is significantly involved in increasing adhesiveness to a metal surface. Accordingly, the pressure-sensitive adhesive composition forming the low-polarity surface coat layer includes, as monomers, polar group-containing monomers (for example, carboxyl group-containing monomers such as acrylic acid and methacrylic acid; hydroxyl groups such as hydroxyethyl (meth) acrylate). A pressure-sensitive adhesive composition in which the content (or content ratio) of a monomer (including a glycidyl group-containing monomer such as glycidyl (meth) acrylate) is reduced can be used.
[0025]
The method for forming the low-polarity surface coat layer is not particularly limited. For example, a pressure-sensitive adhesive composition having a reduced content of a polar group-containing monomer may be applied to the surface of the pressure-sensitive adhesive layer by a known or common application method. A coating method can be adopted.
[0026]
In the weak adhesion treatment method (2), only the outermost surface of the pressure-sensitive adhesive layer is cured with a cross-linking agent to reduce the conformity with the adherend and to reduce the viscous resistance at the time of peeling. It is possible to suppress or prevent an excessive increase in the adhesive force to the outer surface of the housing of the HDD, which is the attached body. When the cross-linking agent reacts with a polar group (such as a carboxyl group) on the outermost surface of the pressure-sensitive adhesive layer, it is possible to further suppress or prevent an increase in the adhesive strength to the outer surface of the HDD housing. Thus, as a method of curing the outermost surface of the pressure-sensitive adhesive layer with a cross-linking agent, for example, a thin layer coating of a processing agent containing a cross-linking agent on the outermost surface of the pressure-sensitive adhesive layer having high adhesion. A curing method can be employed.
[0027]
Examples of the crosslinking agent include an isocyanate-based crosslinking agent, an epoxy-based crosslinking agent, an amine-based crosslinking agent, and metal chelates.
[0028]
The method of thin-layer coating the crosslinking agent-containing treatment agent is not particularly limited, and for example, a method of applying the crosslinking agent-containing treatment agent to the surface of the pressure-sensitive adhesive layer by a known or common application method can be adopted. .
[0029]
In the present invention, as described above, it is important that the weak adhesive treatment is performed only on the outermost surface of the adhesive layer having high adhesiveness. When the entire pressure-sensitive adhesive layer is subjected to a weak pressure-sensitive treatment, the glass transition temperature (Tg) of the entire pressure-sensitive adhesive layer changes (the loss coefficient of the pressure-sensitive adhesive constituting the pressure-sensitive adhesive layer changes), and the vibration damping performance is improved. This has an adverse effect on the temperature characteristics. In addition, there is a problem that the entire pressure-sensitive adhesive layer becomes too hard and the adhesive strength is extremely lowered, and the terminal is peeled off due to the repulsive force of the base material due to lack of flexibility.
[0030]
The adhesive strength of the pressure-sensitive adhesive layer having the outermost surface subjected to a weak adhesive treatment is, for example, a 180 ° peel adhesive strength (peeling speed: 300 mm / min, 23 ° C., an aluminum plate, pressed and left at 60 ° C. for 2 hours. ) Is 2 N / 20 mm or more and 12 N / 20 mm or less (2 to 12 N / 20 mm), preferably 2 N / 20 mm or more and 10 N / 20 mm or less (2 to 10 N / 20 mm), more preferably 2 N / 20 mm or more and 8 N / 20 mm or less (2 ８8 N / 20 mm). If the adhesive strength (180 ° peel adhesive strength) after heating (60 ° C. × 2 hours) is less than 2 N / 20 mm, the end of the label floats or peels off due to insufficient adhesive strength or deformation or rebound of the base material. Problems may occur. On the other hand, if the adhesive strength (180 ° peel adhesive strength) after heating (60 ° C. × 2 hours) exceeds 12 N / 20 mm, a large force is required for peeling, and the peeling workability is reduced, and In some cases, there is a problem of adverse effect on workability such as adhesive residue easily occurring.
[0031]
Although the thickness of the pressure-sensitive adhesive layer is not particularly limited, it is 15 μm or more, preferably 20 to 1000 μm, from the viewpoint of the effect of reducing the noise generated during driving.
[0032]
[Base material]
As shown in FIG. 1, the base material of the pressure-sensitive adhesive label for HDD is a base material (laminated base material) composed of at least three layers in which a resin film layer 2a is laminated on both sides of a metal foil 2b. It is preferred to use 2. Here, as the resin film layer 2a, for example, a resin film made of polyethylene terephthalate (PET), polybutylene terephthalate (PBT), polyimide (PI), polyethylene (PE), polypropylene (PP), or the like can be used. Among them, polyethylene terephthalate is particularly preferred from the viewpoint of economy and durability. As the metal foil 2b, for example, a metal foil made of aluminum foil, iron foil, stainless steel foil, nickel foil, copper foil, or the like can be used. Among them, aluminum foil is particularly preferable from the viewpoint of workability and economy.
[0033]
The pressure-sensitive adhesive label of the present invention has a rigidity capable of exhibiting vibration damping properties, and each of the resin film layer / metal foil / resin film layer in the base material, from the viewpoint of satisfying sticking workability as a pressure-sensitive adhesive label. For example, the following thickness or configuration can be exemplified as the thickness or configuration.
(1) The thickness of the resin film layer on the back side of the pressure-sensitive adhesive label on which the information display portion is formed is usually 6 μm or more and 125 μm or less (6 μm to 125 μm), and preferably 25 μm or more and 125 μm or less (25 μm to 125 μm). If the resin film layer is thinner than 6 μm, the entire base material is governed by the properties of the metal foil, which makes it easy to wrinkle, and because it is very thin, it is very difficult to stably laminate.
Further, by setting the thickness of the resin film layer to 25 μm or more, when an information display portion is formed on the surface of the resin film layer on the back side of the pressure-sensitive adhesive label by a thermal transfer printing means, heat at the time of ink transfer is reduced to metal. The problem of poor printing, which is considered to be caused by dissipating through the foil, can be further improved.
When a barcode or the like is printed as the information display portion, the resin film layer is particularly excellent in readability of a barcode or the like by using a resin film colored white or the like (for example, a white polyethylene terephthalate film or the like). Characteristics are obtained.
[0034]
(2) The thickness of the metal foil is desirably 10 μm or more (preferably 15 to 150 μm) from the viewpoint of maintaining the rigidity of the base material. If the thickness of the metal foil is less than 10 μm, the purpose of increasing the rigidity of the base material may not be achieved. Also, in order to increase the rigidity of the base material, the thicker the better, the better, but if it is too thick, it will be too thick as an adhesive label, which will affect the product thickness of the hard disk drive. It is desirable that the thickness be 150 μm or less.
[0035]
(3) The resin film layer on the side on which the pressure-sensitive adhesive layer is formed is laminated mainly for the purpose of suppressing curling of the pressure-sensitive adhesive label. However, in order to reduce the overall thickness of the pressure-sensitive adhesive label, the thickness of the metal foil layer must be reduced. However, the thickness is preferably as thin as possible, and is usually 6 μm to 50 μm (preferably 6 to 25 μm).
[0036]
The substrate can be manufactured by using a known laminating means such as a dry laminating method, for example, using a metal foil and a resin film layer.
[0037]
Further, the base material may be subjected to surface treatment on one or both sides of the resin film using a known means such as a corona treatment or an easy adhesion treatment to improve the printing property and the anchoring property of the pressure-sensitive adhesive.
[0038]
[Information display section]
An information display portion 4 is formed on one surface (back surface) of a substrate (such as a laminated substrate in which a resin film layer 2a is laminated on both surfaces of a metal foil 2b) 2 of the HDD adhesive label. For example, "usage precautions", "connection method", "recognition / identification items such as product name / manufacturer name" can be formed by ordinary printing means.
[0039]
[Release liner]
In the pressure-sensitive adhesive label for HDD of the present invention, a release liner may be used for protecting the surface weak pressure-sensitive adhesive layer until use. This release liner is a release liner with a small amount of silicone component transferred (migrated) to the surface of the pressure-sensitive adhesive layer in order to prevent problems such as contact failure based on the silicone component in precision electronic devices such as hard disk drives. Is also good.
[0040]
In the pressure-sensitive adhesive label for HDD of the present invention, when a peeling liner is used, the peeling liner is peeled off, and, for example, as shown in FIG. A hard disk drive composed of the main body A and the top cover B can be used by attaching an HDD adhesive label to a top cover and / or an outer surface of a housing main body (housing). By sticking the HDD adhesive label, the noise generated when the hard disk drive is driven can be reduced, and the information display function can be exhibited. In the present invention, the adhesive label for HDD may be attached to at least a part of the housing of the hard disk drive. It is most preferable that the tape is attached to the outer surface of the top cover of the hard disk drive so that the total area of the top cover is 20% or more, preferably 25 to 100%.
[0041]
In addition, when the HDD adhesive label stuck to the hard disk drive is peeled off from the hard disk drive, it can be easily peeled off by hand. In addition, even if the adhesiveness is reduced in this way, the external appearance at the time of sticking is not reduced, and no floating or peeling occurs.
[0042]
【Example】
Hereinafter, the present invention will be described more specifically with reference to Examples, but the present invention is not limited to Examples.
[0043]
(Example 1)
The following base material A was used as the base material.
Substrate A: A substrate A composed of a white polyethylene terephthalate film layer (thickness: 25 μm) / aluminum foil (thickness: 15 μm) / a transparent polyethylene terephthalate film layer (thickness: 9 μm) was prepared by a lamination method using dry lamination. .
[0044]
The following pressure-sensitive adhesive composition A was used as the pressure-sensitive adhesive.
Adhesive composition A: 100 parts by weight of a UV syrup composed of isooctyl acrylate and acrylic acid [isooctyl acrylate / acrylic acid = 90/10 (weight ratio)] as a formulation, and trimethylolpropanetri as a crosslinking agent Acrylic pressure-sensitive adhesive composition (pressure-sensitive adhesive composition) obtained by mixing 0.14 parts by weight of acrylate (TMPTA) and 1 part by weight of an isocyanate-based crosslinking agent (trade name: "Coronate L" manufactured by Nippon Polyurethane Industry Co., Ltd.) A was prepared.
[0045]
On the transparent polyethylene terephthalate film layer side surface of the base material A, the pressure-sensitive adhesive composition A is applied so that the thickness after drying becomes 25 μm, and immediately after the application, a release treatment with a silicone-based release agent is performed. The applied polyethylene terephthalate film (release liner) is bonded so that the pressure-sensitive adhesive compound A layer and the silicone-based release agent layer are in contact with each other, and then about 3000 mj / cm using a metal halide lamp. ² UV irradiation (UV irradiation) was performed to cure the adhesive.
[0046]
After curing, the release liner was peeled off, and the following treating agent A was applied on the surface of the pressure-sensitive adhesive layer so that the thickness after drying was about 2 μm, and heat treatment (drying) was performed at 130 ° C. for 3 minutes. Then, the release liner was adhered again to produce an adhesive label A.
[0047]
Treatment agent A: acrylic polymer (copolymer of 2-ethylhexyl acrylate and acrylic acid; 2-ethylhexyl acrylate / acrylic acid = 97/3 (weight ratio); weight-average molecular weight: about 700,000); isocyanate-based A liquid mixture (weight ratio of solid content: acrylic polymer / isocyanate crosslinking agent = 100/5) with a cross-linking agent (trade name “Coronate L” manufactured by Nippon Polyurethane Industry Co., Ltd.) is diluted to have a solid content of about Treatment agent A was prepared at 20% by weight.
[0048]
(Example 2)
The following base material B was used as the base material.
Substrate B: A substrate B composed of a white polyethylene terephthalate film layer (thickness: 25 μm) / aluminum foil (thickness: 30 μm) / a transparent polyethylene terephthalate film layer (thickness: 9 μm) was prepared by a lamination method using dry lamination. .
[0049]
The following pressure-sensitive adhesive composition B was used as the pressure-sensitive adhesive.
Adhesive preparation B: 100 parts by weight of a UV syrup composed of isooctyl acrylate and acrylic acid [isooctyl acrylate / acrylic acid = 90/10 (weight ratio)] as a preparation, and TMPTA as a crosslinking agent in an amount of 0.1%. An acrylic pressure-sensitive adhesive composition (pressure-sensitive adhesive composition) B obtained by mixing 1 part by weight and 1.5 parts by weight of an isocyanate-based crosslinking agent (trade name “Coronate L” manufactured by Nippon Polyurethane Industry Co., Ltd.) was prepared.
[0050]
On the transparent polyethylene terephthalate film layer side surface of the base material B, the pressure-sensitive adhesive composition B is applied so that the thickness after drying becomes 25 μm, and immediately after the application, a release treatment with a silicone-based release agent is performed. The applied polyethylene terephthalate film (release liner) is bonded so that the pressure-sensitive adhesive composition B layer and the silicone-based release agent layer are in contact with each other, and then about 3000 mj / cm by a metal halide lamp. ² UV irradiation (UV irradiation) was performed to cure the adhesive.
[0051]
After curing, the release liner was peeled off, and the following treating agent B was applied to the surface of the pressure-sensitive adhesive layer so that the thickness after drying became about 2 μm, and heat treatment (drying) was performed at 130 ° C. for 3 minutes. Then, the release liner was adhered again to produce an adhesive label B.
[0052]
Treatment agent B: acrylic polymer (copolymer of 2-ethylhexyl acrylate and acrylic acid; 2-ethylhexyl acrylate / acrylic acid = 97/3 (weight ratio); weight-average molecular weight of about 700,000); isocyanate-based A mixture of a cross-linking agent (trade name “Coronate L” manufactured by Nippon Polyurethane Industry Co., Ltd.) (weight ratio of solid content: acrylic polymer / isocyanate cross-linking agent = 100/7) was diluted to a solid content of about Treatment agent B was prepared at 20% by weight.
[0053]
(Comparative Example 1)
An adhesive label C was produced in the same manner as in Example 1 except that the surface treatment with the treating agent A was not performed.
[0054]
(Comparative Example 2)
An adhesive label D was prepared in the same manner as in Example 2 except that the surface treatment with the treating agent B was not performed.
[0055]
(Evaluation)
With respect to the adhesive labels (adhesive labels A to D) obtained in the examples and comparative examples, the adhesive strength, appearance and vibration damping were measured by the following methods relating to the measurement of adhesive strength, evaluation of appearance and evaluation of vibration damping properties. The properties were evaluated.
[0056]
(Measurement of adhesive strength)
The adhesive labels (adhesive labels A to D) obtained in Examples and Comparative Examples were cut into a width of 20 mm, and pressed at room temperature on an aluminum plate as an adherend using a rubber roller (2 kg) (1). Attached, aged at room temperature for 30 minutes, further placed in an oven at 60 ° C. for 2 hours, taken out of the oven, allowed to cool for 1 hour, and then peeled at 180 ° (peeling speed) (300 mm / min, 23 ° C.), and the adhesive strength of the adhesive labels obtained in Examples and Comparative Examples to an aluminum plate was measured to evaluate the adhesiveness or peelability. The measurement results are shown in Table 1.
[0057]
(Evaluation of appearance)
In the measurement of the adhesive force, after heat aging at 60 ° C. for 2 hours, the presence or absence of floating or peeling on the outer periphery of the applied adhesive labels A to D was visually checked. The observation results are shown in Table 1.
[0058]
(Evaluation of damping characteristics)
The pressure-sensitive adhesive labels obtained in Examples and Comparative Examples were affixed to 85% (surface area ratio) of the outer surface of the housing of a commercially available 2.5-inch hard disk drive. The noise level before and after pasting was measured by the measurement method described above, and the difference was evaluated as a vibration damping characteristic. The evaluation results are shown in Table 1.
[0059]
<Method of measuring noise level (sound generated during operation)>
The hard disk drive with the adhesive label attached to the top cover was powered on and driven, and the noise level during driving (the sound generated during driving) was measured by the following method.
[0060]
The measurement of the noise level was performed in an anechoic room. A test table was placed in an anechoic chamber, and placed on a highly sound-insulating rubber-based foam (thickness: 20 mm) with the surface of the hard disk drive to be subjected to noise measurement to be a part to which an adhesive label was to be attached facing upward. (The rubber foam with high sound insulation is used to prevent solid-borne noise from the test bench due to vibration propagation of the hard disk drive and to block noise from the bottom of the hard disk drive.)
[0061]
After the hard disk drive was driven and left until the noise level became stable, the noise level was measured with a free-field microphone placed 300 mm above the center. The measured values were obtained by performing an averaging process for 20 seconds using the A characteristic as the auditory sensation correction and expressing the frequency range as an overall value of 20 to 20,000 Hz.
[0062]
[Table 1]

[0063]
As is clear from Table 1, the pressure-sensitive adhesive labels according to Examples 1 and 2 have an appropriate adhesive strength and an excessive rise is suppressed, so that when peeling, the pressure-sensitive adhesive labels can be easily peeled. it can. In addition, no adhesive residue occurs after peeling. In particular, even if the adhesiveness is reduced to improve the releasability, even if the tape is attached to a hard disk drive, no floating or peeling occurs, and excellent appearance can be maintained. Furthermore, it also has excellent vibration damping characteristics, and it is possible to reduce the sound generated during driving by 1 dB or more simply by sticking it to the sticking portion of the display label of a currently marketed hard disk drive.
[0064]
Note that the pressure-sensitive adhesive labels according to Comparative Examples 1 and 2 have a strong pressure-sensitive adhesive force, and require time and effort for peeling, and after peeling, adhesive residue may be observed on the sticking surface of the housing of the hard disk drive.
[0065]
【The invention's effect】
The pressure-sensitive adhesive label of the present invention, having the above-described configuration, can achieve both various functions of displaying information as a pressure-sensitive adhesive label and a function of reducing noise generated when a hard disk drive is driven. A slight rise is suppressed, and when peeling, it is possible to easily peel. In addition, when attached, no floating or peeling occurs, and excellent appearance is maintained.
Therefore, with the pressure-sensitive adhesive label of the present invention, the work of peeling the pressure-sensitive adhesive label can be greatly improved when it is erroneously applied or when rework occurs, which can contribute to an improvement in work efficiency.
[Brief description of the drawings]
FIG. 1 is a schematic sectional view showing one embodiment of an adhesive label for a hard disk drive of the present invention.
FIG. 2 is a schematic view showing a hard disk drive to which an adhesive label for a hard disk drive of the present invention is attached.
[Explanation of symbols]
1 Adhesive labels for hard disk drives
2 Base material
2a resin film layer
2b metal foil
3 Adhesive layer with weak adhesive treatment on the outermost surface
4 Information display section
A Housing body
B Top cover

Claims (5)

It has an information display part on one side of the base material and an adhesive layer on the other side, and it can reduce the noise generated when driving the hard disk drive by being attached to the outer surface of the housing of the hard disk drive An adhesive label for a hard disk drive, wherein a weak adhesive treatment is applied to an outermost surface of the adhesive layer. The pressure-sensitive adhesive label for a hard disk drive according to claim 1, wherein the 180 ° peel adhesive strength (peeling speed: 300 mm / min, 23 ° C., against an aluminum plate, left at 60 ° C. for 2 hours after pressing) is 2 to 12 N / 20 mm. The hard disk drive according to claim 1, wherein the weak adhesive treatment is a weak adhesive treatment for reducing the ratio of polar groups on the outermost surface of the adhesive layer, or a weak adhesive treatment for curing the outermost surface of the adhesive layer with a crosslinking agent. For adhesive labels. The pressure-sensitive adhesive label for a hard disk drive according to any one of claims 1 to 3, wherein the substrate is formed by laminating a resin film layer on both surfaces of a metal foil. The pressure-sensitive adhesive label for a hard disk drive according to claim 1, wherein the pressure-sensitive adhesive constituting the pressure-sensitive adhesive layer has a loss coefficient of 0.5 to 5.0 at 20 ° C. 5.

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