JP6930904B2 - Adhesive sheet - Google Patents

Description

The present invention relates to an adhesive sheet.

Conventionally, there is an adhesive sheet used to close a gap. For example, Patent Document 1 discloses an adhesive sheet that closes and seals a gap formed in a hard disk drive. The adhesive sheet of Patent Document 1 ensures airtightness by suppressing wrinkles so that when the adhesive sheet is attached to the adherend, the gaps in the adherend and the outside do not communicate with each other through the cavities caused by the wrinkles. I try to do it.

Japanese Unexamined Patent Publication No. 2014-162874

However, the surface of the adherend to which the adhesive sheet is attached is not only a flat and relatively simple surface, but also has a shape in which wrinkles are more likely to occur than a surface having many irregularities and steps. In the case of manual pasting, there are variations in the skill of the worker, so even if wrinkles can be suppressed to some extent, it is difficult to completely eliminate them.

For this reason, some wrinkles may remain, and as a result of such wrinkles being overlooked, there is a risk that the original function of the adhesive sheet, which is to close the gaps between the adherends and secure the airtightness, is impaired. ..

The present invention has been made in view of such a problem, and an object of the present invention is to provide an adhesive sheet in which wrinkles generated when attached to an adherend can be easily found.

The pressure-sensitive adhesive sheet of the present invention for achieving the above object has a base material layer formed of a metal material and a pressure-sensitive adhesive layer provided on the back surface side, which is one side of the base material layer. A resin layer provided integrally with the base material layer is provided between the pressure-sensitive adhesive layer and the back surface, and at least one of the front surface side opposite to the back surface side. On the front surface side of the pressure-sensitive adhesive sheet of the present invention, the 45 ° mirror surface gloss measured according to JIS Z8741: 1997 is 400% or more and 800% or less.

According to the adhesive sheet having the above structure, even if wrinkles occur, the wrinkles are conspicuous due to the gloss on the front surface side, so that wrinkles can be easily found.

It is a figure which shows the adhesive sheet of 1st Embodiment. It is a figure which shows typically the light which specularly reflects at the angle of 45 ° on the front surface side of the pressure-sensitive adhesive sheet of 1st Embodiment. It is a perspective view which shows the sticking of an adhesive sheet to an adherend. It is a perspective view which shows the occurrence of wrinkles by sticking an adhesive sheet to an adherend. It is a figure which shows the adhesive sheet of 2nd Embodiment. It is a figure which shows the adhesive sheet of Example 1 and Comparative Example 1. It is a figure which shows the adhesive sheet of Example 2 and Comparative Example 2.

Hereinafter, embodiments of the present invention will be described with reference to the attached drawings. The dimensional ratios in the drawings are exaggerated for convenience of explanation and differ from the actual ratios.

<First Embodiment>
As shown in FIG. 1, the pressure-sensitive adhesive sheet 100 of the first embodiment has a base material layer 110, a resin layer 120, a resin layer 121, a primer layer 130, a pressure-sensitive adhesive layer 140, and a release liner 150. ..

The base material layer 110 is made of a metal material. The metal material forming the base material layer 110 is, for example, aluminum (Al), but is not limited to this, and other metal materials may be used.

The thickness of the base material layer 110 is designed in consideration of, for example, the followability of the shape to the adherend to which the adhesive sheet 100 is attached. For example, it is larger than 7 μm and less than 30 μm, preferably larger than 7 μm and 20 μm or less. Yes, but not limited to these.

The resin layer 120 is provided integrally with the base material layer 110 between the back surface 111, which is one surface of the base material layer 110, and the pressure-sensitive adhesive layer 140. The resin layer 121 is provided integrally with the base material layer 110 on the front surface 112 side opposite to the back surface 111, and has transparency.

The material for forming the resin layer 120 and the resin layer 121 is, for example, polyethylene terephthalate (PET), but the present invention is not limited to this, and other resins may be used. Further, the present invention is not limited to a form in which the material for forming the resin layer 120 and the material for forming the resin layer 121 are the same, and the present invention includes a form in which they are different.

The total thickness (total thickness) of the thickness of the resin layer 120 and the thickness of the resin layer 121 is designed in consideration of, for example, the strength against tearing and the effect of suppressing wrinkles, and is, for example, 25 μm or more and 40 μm or less, but is limited to this. Not done. The thickness of the resin layer 120 and the thickness of the resin layer 121 may be the same or different.

The primer layer 130 is provided between the resin layer 120 and the pressure-sensitive adhesive layer 140, and improves the adhesion between them. The material for forming the primer layer 130 is, for example, a polyurethane-based resin such as a polyurethane elastomer or a modified polyurethane elastomer, but the material is not limited to this, and other resins may be used. The thickness of the primer layer 130 is, for example, 0.01 μm or more and 3 μm or less, but is not limited thereto.

The pressure-sensitive adhesive layer 140 can be formed of, for example, a pressure-sensitive adhesive such as an acrylic pressure-sensitive adhesive, a polyester-based pressure-sensitive adhesive, a polyurethane-based pressure-sensitive adhesive, or a rubber-based pressure-sensitive adhesive. Not limited. The thickness of the pressure-sensitive adhesive layer 140 is, for example, 25 μm, but is not limited thereto.

The release liner 150 is removably arranged on the surface of the pressure-sensitive adhesive layer 140 to prevent foreign substances such as dust from adhering to the surface of the pressure-sensitive adhesive layer 140. The composition of the release liner 150 is not particularly limited, but for example, a release film made of various resins coated with a release agent such as silicone, or high-quality paper or kraft paper coated with the release agent on the surface. , Glassine paper, etc. The pressure-sensitive adhesive sheet 100 is attached to the adherend via the pressure-sensitive adhesive layer 140 that is exposed by peeling off the release liner 150.

As shown in FIG. 2, in the adhesive sheet 100, the 45 ° mirror gloss L measured according to JIS Z8741: 1997 on the front surface 112 side is 400% or more and 800% or less, more preferably 500% or more. It is 700% or less, and the adhesive sheet 100 shows a strong luster on the front surface 112 side.

The 45 ° mirror gloss L can be obtained from the reflected light having a reflection angle of 45 ° that is mirror-reflected when the adhesive sheet 100 is irradiated with light at an incident angle of 45 ° from the front surface 112 side. .. Specular reflection is the reflection of light that follows the law of reflection, such as the reflection on the surface of a mirror.

The reflection of light in the pressure-sensitive adhesive sheet 100 mainly occurs on the surface of the base material layer 110 formed of the metal material, and on the front surface 112 side, most of the incident light passes through the resin layer 121. Reflects on the surface 112. Therefore, it is preferable that the front surface 112 of the base material layer 110 easily reflects light so that the pressure-sensitive adhesive sheet 100 exhibits a strong gloss on the front surface 112 side.

On the other hand, what kind of mirror glossiness the adhesive sheet 100 exhibits on the back surface 111 side is not particularly limited. For example, the 45 ° mirror gloss L on the front surface 112 side and the 45 ° mirror gloss L on the back surface 111 side may be about the same. Alternatively, the 45 ° mirror surface glossiness on the back surface 111 side may be smaller than the 45 ° mirror surface glossiness L on the front surface 112 side. In this case, for example, the front surface 112 is a glossy surface that is smoother than the back surface 111, and the back surface 111 is a matte surface having fine irregularities. The 45 ° mirror gloss on the back surface 111 side can be measured in the same manner as on the front surface 112 side, for example, in a state where the release liner 150 is peeled off and the adhesive layer 140 is exposed.

As shown in FIG. 3, the adhesive sheet 100 has the release liner 150 peeled off and is attached to the hard disk drive 1 which is an adherend to close the gap 1a (a vacant portion formed in the adherend). Used.

The hard disk drive 1 has a case 2 having an opening and a main body 3 housed in the case 2. The case 2 is formed of, for example, a resin, but is not limited to this, and may be formed of a metal. The main body 3 includes precision parts such as a magnetic disk, a spindle motor, and a magnetic head. A gap 1a is formed between the case 2 and the main body 3.

By closing the gap 1a, the adhesive sheet 100 prevents substances such as moisture that adversely affect the hard disk drive 1 from entering the main body 3. Alternatively, it prevents gas such as helium filled in the main body 3 from leaking in order to improve the performance of the device.

As shown in FIG. 4, when the adhesive sheet 100 is attached, if there are wrinkles 101, the gap 1a communicates with the outside through the cavities caused by the wrinkles 101, which may impair the airtightness. In particular, for example, if the wrinkle 101 is small and the operator overlooks the wrinkle 101, the airtightness may remain impaired.

However, in the pressure-sensitive adhesive sheet 100 of the present embodiment, the 45 ° mirror surface gloss L on the front surface 112 side is 400% or more and 800% or less, and the wrinkles 101 are conspicuous due to the strong gloss. Therefore, according to the adhesive sheet 100 of the present embodiment, the wrinkles 101 are easy to find and hard to overlook.

In the present embodiment, the mirror glossiness L shows a large value of 400% or more and 800% or less at an angle of 45 ° with respect to the normal direction of the surface of the pressure-sensitive adhesive sheet 100. Therefore, even if the adherend 1 is not extremely tilted or the line of sight is moved significantly so as to be viewed from a larger angle such as 60 ° or 85 ° with respect to the same direction, the adhesive sheet 100 can be used. The reflected light naturally gets into the eyes of the operator. Therefore, the wrinkles 101 are particularly easy to find, and oversight of the wrinkles 101 can be effectively prevented.

If the wrinkles 101 are not overlooked, the operator can eliminate the wrinkles 101 by, for example, partially peeling off the wrinkles 101 and their surroundings and reattaching them so as to follow the shape of the hard disk drive 1. And can ensure airtightness.

Alternatively, the operator can secure the airtightness by peeling off all the adhesive sheet 100 having the wrinkles 101 and reattaching another new adhesive sheet 100 so as to follow the shape of the hard disk drive 1. can do.

<Second Embodiment>
As shown in FIG. 5, in the pressure-sensitive adhesive sheet 200 of the second embodiment, the resin layer 220 is provided only on the front surface 112 side of one of them, not on both sides of the base material layer 110 as in the first embodiment. Have. Since other configurations are the same as those of the first embodiment, the same reference numerals as those of the first embodiment are used for them, and duplicate description thereof will be omitted here.

The resin layer 220 is formed of, for example, polyethylene terephthalate (PET), but is not limited to this, and may be formed of other resins. The thickness of the resin layer 220 is designed in consideration of, for example, the strength against tearing and the effect of suppressing wrinkles, and is, for example, 25 μm or more and 40 μm or less, but is not limited thereto.

A form in which the resin layer 220 is provided only on the back surface 111 side, not on the front surface 112 side, is also included in the scope of the present invention, but the resin layer is provided on the front surface 112 side as in the present embodiment. By providing the 220, the base material layer 110 can be effectively protected. The resin layer 220 has transparency.

Similarly to the first embodiment, the adhesive sheet 200 of the present embodiment also has a 45 ° mirror gloss L on the front surface 112 side of 400% or more and 800% or less, more preferably 500% or more and 700% or less. Is. With this configuration, the wrinkles 101 as shown in FIG. 4 are conspicuous. Therefore, even in the present embodiment, the wrinkles 101 are easy to find and hard to overlook as in the first embodiment.

Next, Examples and Comparative Examples will be described.

<Example 1 and Comparative Example 1>
As shown in FIG. 6, the pressure-sensitive adhesive sheet 100A of Example 1 and the pressure-sensitive adhesive sheet 100B of Comparative Example 1 have similar laminated structures to each other similar to those of the first embodiment, but the base material layer 110A of Example 1 The gloss of the front surface 112A and the gloss of the front surface 112B of the base material layer 110B of Comparative Example 1 are different.

The pressure-sensitive adhesive sheet 100A of Example 1 has a resin layer 121A, a base material layer 110A, a resin layer 120A, and a pressure-sensitive adhesive layer 140A in this order in the stacking direction.

The pressure-sensitive adhesive sheet 100B of Comparative Example 1 has a resin layer 121A, a base material layer 110B, a resin layer 120A, and a pressure-sensitive adhesive layer 140A in this order in the stacking direction.

In Example 1 and Comparative Example 1, the resin layers 120A and 121A and the pressure-sensitive adhesive layer 140A are common to each other. The resin layer 120A and the resin layer 121A are each formed of polyethylene terephthalate (PET) and have a thickness of 16 μm.

The base material layer 110A of Example 1 and the base material layer 110B of Comparative Example 1 are both formed of aluminum (Al) and have a thickness of 12 μm.

The gloss of the front surface 112A of the base material layer 110A is stronger than the gloss of the front surface 112B of the base material layer 110B. Such a difference in gloss can be caused by changing the surface roughness. The front surface 112A of the base material layer 110A is a glossy surface having a small surface roughness and a strong gloss. The front surface 112B of the base material layer 110B is a matte surface having a large surface roughness and a weak gloss.

The present inventor measured the mirror glossiness of the pressure-sensitive adhesive sheet 100A of Example 1 on the front surface 112A side and the pressure-sensitive adhesive sheet 100B of Comparative Example 1 on the front surface 112B side. The present inventor measured their mirror glossiness by Gloss Meter VG 7000 manufactured by Nippon Denshoku Kogyo Co., Ltd. according to JIS Z8741: 1997. At that time, the present inventor measured the mirror glossiness by setting the incident angle and the reflection angle of light, θ, to 45 °, 60 °, and 85 °.

<Example 2 and Comparative Example 2>
As shown in FIG. 7, the pressure-sensitive adhesive sheet 200A of Example 2 and the pressure-sensitive adhesive sheet 200B of Comparative Example 2 have similar laminated structures to each other similar to those of the second embodiment, but the base materials layers 110A and 110B. The front surfaces 112A and 112B have different glosses.

The pressure-sensitive adhesive sheet 200A of Example 2 has a resin layer 220A, a base material layer 110A, and a pressure-sensitive adhesive layer 140A in this order in the stacking direction.

The pressure-sensitive adhesive sheet 200B of Comparative Example 2 has a resin layer 220A, a base material layer 110B, and a pressure-sensitive adhesive layer 140A in this order in the stacking direction.

The resin layer 220A is common to Example 2 and Comparative Example 2, is formed of polyethylene terephthalate (PET), and has a thickness of 25 μm.

The base material layer 110A is the same as that of Example 1, and the base material layer 110B is the same as that of Comparative Example 1. For this reason, duplicate description of them will be omitted.

The present inventor compares the mirror glossiness of the front surface 112A side of the pressure-sensitive adhesive sheet 200A of Example 2 and the front surface 112B side of the pressure-sensitive adhesive sheet 200B of Comparative Example 2 with respect to the above-mentioned Example 1 and the above-mentioned comparison. The measurement was performed in the same manner as in Example 1. Table 1 below shows the measurement results of the mirror glossiness of Example 1 and Comparative Example 1 and Example 2 and Comparative Example 2.

Regarding the measurement results, when Example 1 and Comparative Example 1 were compared and Example 2 and Comparative Example 2 were compared, the mirror glossiness of both was about the same at a large angle of θ = 85 °, but θ At = 60 °, the mirror glossiness of the example shows a value of 3 times or more as compared with the comparative example, and at θ = 45 °, the mirror surface gloss of the example shows a value as large as about 5 times as compared with the comparative example. Indicated.

In fact, the adhesive sheets 100B and 200B of the comparative examples had a weak gloss visually recognized from the front surface 112B side, whereas the adhesive sheets 100A and 200A of the examples were visually recognized from the front surface 112A side. The gloss to be done was strong.

Further, the present inventor confirmed the relationship between the conspicuousness of wrinkles and the gloss of the adhesive sheets 100A, 100B, 200A, and 200B in a state of being attached to a hard disk drive which is an adherend having irregularities. As for the examples, it was found that wrinkles were more noticeable due to the gloss and wrinkles were easily found as compared with the comparative examples.

From the above, if the mirror glossiness is larger than the measured values (366%, 382%) of the examples when θ = 60 °, 400% or more, more preferably 500% or more, it is compared with the comparative example. The gloss becomes stronger and wrinkles are noticeable, making it easier to find wrinkles.

On the other hand, even if the gloss is too strong, it becomes difficult to find wrinkles due to glare. Therefore, the upper limit of the mirror glossiness is preferably 800% or less, more preferably 700% or less.

The present invention is not limited to the above-described embodiments and examples, and various modifications can be made within the scope of the claims.

For example, the size and shape of the adhesive sheet are not particularly limited, and can be appropriately designed according to the adherend to which the adhesive sheet is attached.

Further, the adherend to which the adhesive sheet is attached is not limited to the hard disk drive as in the above-described embodiment and embodiment, and may be another object having a gap. Further, the pressure-sensitive adhesive sheet of the present invention is not limited to the use of closing a narrow gap such as the gap 1a of the above embodiment, and may be used to close a relatively large opening.

Further, the wrinkles 101 of the above embodiment have a relatively simple shape and a certain size, but the shape and size of the wrinkles generated on the adhesive sheet, and the location and number of wrinkles are determined in the above-described embodiment. It is not limited to the form.

1 Hard disk drive (attachment),
1a Gap (vacant part formed in the adherend),
2 cases,
3 Main body,
100, 200 adhesive sheet,
101 wrinkles,
110 substrate layer,
111 back side,
112 Front face,
120, 121, 220 resin layers,
130 primer layer,
140 Adhesive layer,
150 peeling liner,
L 45 ° mirror gloss measured according to JIS Z8741: 1997 on the front side.

Claims (2)

A base layer formed of a metallic material and
An adhesive layer provided on the back side, which is one side of the base material layer, and
A resin layer provided integrally with the base material layer is provided between the pressure-sensitive adhesive layer and the back surface, and at least one of the front surface side opposite to the back surface side.
An adhesive sheet having a 45 ° mirror surface gloss measured according to JIS Z8741: 1997 on the front surface side of 400% or more and 800% or less. The adhesive sheet according to claim 1, wherein the vacant portion formed on the adherend is closed and attached to the adherend.

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