JP2016014075A - Double-sided adhesive tape and substrate for double-sided adhesive tape - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a double-sided adhesive tape or the like which has excellent waterproofness while improving blocking resistance of a substrate.SOLUTION: A double-sided adhesive tape 10 includes a substrate 20 and adhesive layers 31 and 32 laminated on both surfaces of the substrate 20. The substrate 20 has: a first substrate layer 21 formed of a non-foamed body of an elastomer mainly composed of an ethylene-vinyl acetate copolymer; and a second substrate layer 22 which is laminated on the first substrate layer 21, is formed of a non-foamed body of an elastomer mainly composed of an ethylene-vinyl acetate copolymer having a vinyl acetate content (VA%) of 11-20 wt.% inclusive, and contains a filler.

Description

  The present invention relates to a double-sided pressure-sensitive adhesive tape and a base material for double-sided pressure-sensitive adhesive tape.

In an electronic device such as a mobile phone terminal having a display unit that displays an image or the like, a double-sided adhesive tape may be used to attach a surface plate provided on the surface of the display unit to a housing of the electronic device.
As a background art, for example, Patent Document 1 describes a double-sided pressure-sensitive adhesive tape having a resin foam as a base material as a double-sided pressure-sensitive adhesive tape for fixing a casing and a surface plate of a mobile phone terminal. However, when a double-sided pressure-sensitive adhesive tape using a resin foam as a base material is used with a narrow width of the double-sided pressure-sensitive adhesive tape, the waterproof property may be lowered.
In order to solve such a problem, Patent Document 2 describes a double-sided pressure-sensitive adhesive tape based on an elastomer non-foamed material as a double-sided pressure-sensitive adhesive tape for fixing a casing and a surface plate of a mobile phone terminal. ing.

JP 2009-108314 A JP 2012-167247 A

By the way, generally, when producing a double-sided pressure-sensitive adhesive tape having a base material made of an elastomer non-foamed material, after the base material is produced and wound, the pressure-sensitive adhesive layer is formed on the base material while rewinding the wound base material. May be performed.
When a non-foamed elastomer having high flexibility is used as the substrate, so-called blocking may occur in which the substrates adhere to each other when the substrate is wound. And when blocking generate | occur | produces, it will become difficult to rewind a base material and a double-sided adhesive tape may not be produced.
An object of this invention is to provide the double-sided adhesive tape etc. which were excellent in waterproofness, improving the blocking resistance of a base material.

For this purpose, the double-sided pressure-sensitive adhesive tape of the present invention comprises a base material and an adhesive layer laminated on both surfaces of the base material, and the base material contains an ethylene / vinyl acetate copolymer as a main component. A first base layer made of a non-foamed elastomer and an ethylene / vinyl acetate copolymer layer laminated on the first base layer and having a vinyl acetate content (VA%) of 11 wt% to 20 wt% It is made of an elastomer non-foamed body mainly composed of coalescence, and has a second base material layer containing a filler.
Here, the first base material layer may be characterized in that VA% is 1% by weight or more and 40% by weight or less.
The filler contained in the second base material layer may have an average particle diameter of 10 μm or more and 50 μm or less.
Further, the filler content in the second base material layer may be 2 wt% or more and 10 wt% or less with respect to the elastomer constituting the second base material layer.
Furthermore, the ratio of the thickness of the first base material layer to the thickness of the second base material layer may be in the range of 1: 4 to 4: 1.
Furthermore, the base material may be characterized in that the second base material layer is laminated on both surfaces of the first base material layer.
Further, from another viewpoint, the base material for the double-sided pressure-sensitive adhesive tape of the present invention includes a first base material layer made of an elastomer non-foamed material mainly composed of an ethylene / vinyl acetate copolymer, and the first base material. It is laminated on both sides of the material layer, and is made of an elastomer non-foamed material mainly composed of an ethylene / vinyl acetate copolymer having a vinyl acetate content (VA%) of 11% by weight or more and 20% by weight or less, and includes a filler. It has a 2nd base material layer, and is wound up by roll shape, It is characterized by the above-mentioned.

  ADVANTAGE OF THE INVENTION According to this invention, the double-sided adhesive tape etc. excellent in waterproofness can be provided, improving the blocking resistance of a base material.

It is the figure which showed an example of the structure of the double-sided adhesive tape to which this Embodiment is applied. It is the figure which showed an example of the usage method of a double-sided adhesive tape. It is the figure which showed the structure of the double-sided adhesive tape of Embodiment 2. FIG. (A) is the figure which showed an example of the attenuation curve of the acceleration measured with an accelerometer, (b) is an enlarged view of the 1st wave of an attenuation curve.

<Embodiment 1>
Embodiments of the present invention will be described below.
[Configuration of Double-sided Adhesive Tape 10]
FIG. 1 is a diagram illustrating an example of a configuration of a double-sided pressure-sensitive adhesive tape 10 to which the exemplary embodiment is applied. As shown in FIG. 1, the double-sided pressure-sensitive adhesive tape 10 of the present embodiment includes a base material 20 and pressure-sensitive adhesive layers 31 and 32 that are laminated on both surfaces of the base material 20. In the present embodiment, release liners 51 and 52 having releasability from the adhesive layers 31 and 32 are provided on both sides of the double-sided adhesive tape 10.
Then, the structure of each layer of the double-sided adhesive tape 10 is demonstrated concretely.

(Substrate 20)
As shown in FIG. 1, the base material 20 of this Embodiment is an example of the base material for double-sided adhesive tapes, and the 1st base material layer 21 and the 1st base material layer 21 provided in both front and back both surfaces are shown. 2 It is comprised by the laminated structure with the base material layer 22. FIG.

(First base material layer 21)
The 1st base material layer 21 is comprised from the non-foamed material of an elastomer. More specifically, the 1st base material layer 21 is comprised from the non-foamed material of the elastomer which has ethylene-vinyl acetate copolymer (EVA) as a main component. In addition, the 1st base material layer 21 of this Embodiment does not contain the filler unlike the 2nd base material layer 22 mentioned later.
In general, an elastomer non-foamed body having an ethylene-vinyl acetate copolymer as a main component tends to be more flexible as the vinyl acetate content (VA%) is higher. When an elastomer non-foamed material mainly composed of an ethylene-vinyl acetate copolymer is used as the first base material layer 21, the vinyl acetate content (VA%) in the ethylene-vinyl acetate copolymer is 1% by weight. The content is preferably in the range of 40% by weight or less.

When the VA% in the first base material layer 21 is less than 1% by weight, the first base material layer 21 tends to be hard, and as a result, the base material 20 becomes hard, so the flexibility of the double-sided pressure-sensitive adhesive tape 10 is reduced. There is a fear. In this case, when the double-sided pressure-sensitive adhesive tape 10 is attached to an adherend having a curved surface or irregularities, the followability of the double-sided pressure-sensitive adhesive tape 10 may be reduced. Moreover, since the 1st base material layer 21 tends to become hard when VA% in the 1st base material layer 21 is less than 1 weight%, there exists a possibility that the impact resistance mentioned later and the effect of shock absorption may become inadequate. is there.
On the other hand, when the VA% in the first base material layer 21 is more than 40% by weight, the first base material layer 21 tends to be soft. In this case, in the processing step after the manufacture of the double-sided pressure-sensitive adhesive tape 10, when the double-sided pressure-sensitive adhesive tape 10 is punched into a desired shape, the base material 20 sticks to a blade or mold used for punching and the base material 20 extends. There is a fear. In other words, there is a possibility that the punching characteristics of the double-sided pressure-sensitive adhesive tape 10 including the base material 20 may deteriorate.

From another point of view, the VA% of the first base material layer 21 is more preferably higher than the VA% of the second base material layer 22. That is, as described later, since the VA% of the second base material layer 22 is in the range of 11% by weight to 20% by weight, the VA% of the first base material layer 21 is 21% by weight or more and 40% by weight. The following range is more preferable.
Although details will be described later, since the second base material layer 22 contains a filler, it is harder than the first base material layer 21. In this case, the VA% of the first base material layer 21 is made higher than the VA% of the second base material layer 22 and the flexibility of the first base material layer 21 is increased, so that the impact applied to the double-sided adhesive tape 10 is reduced. It becomes easy to absorb in the 1st base material layer 21, and the impact resistance of the double-sided adhesive tape 10 is improved.

(Second base material layer 22)
The 2nd base material layer 22 is comprised from the non-foamed material of the elastomer which added the filler. More specifically, the 2nd base material layer 22 is comprised from the non-foamed material of the elastomer which added the filler and has ethylene-vinyl acetate copolymer (EVA) as a main component. Although details will be described later, in the present embodiment, since the second base material layer 22 includes a filler, the first base material layer 21 and the second base material layer 22 are highly flexible ethylene-vinyl acetate copolymer. Even when the coalescence is used, the occurrence of blocking due to interlayer adhesion is suppressed when the substrate 20 is wound up in the manufacturing process of the double-sided pressure-sensitive adhesive tape 10.

In the second base material layer 22 of the present embodiment, the vinyl acetate content (VA%) in the ethylene-vinyl acetate copolymer is in the range of 11 wt% to 20 wt%.
When the VA% in the second base material layer 22 is less than 11% by weight, the second base material layer 22 tends to be hard and the flexibility of the double-sided pressure-sensitive adhesive tape 10 may be reduced. In this case, when the double-sided pressure-sensitive adhesive tape 10 is attached to an adherend having a curved surface or irregularities, the followability of the double-sided pressure-sensitive adhesive tape 10 may be reduced.
On the other hand, when the VA% in the second base material layer 22 is more than 20% by weight, the second base material layer 22 tends to be soft. In this case, even when a filler is included in the second base material layer 22 in the manufacturing process of the double-sided pressure-sensitive adhesive tape 10 to be described later, blocking due to interlayer adhesion may occur when the base material 20 is wound up.

It does not specifically limit as a filler added to the 2nd base material layer 22 of this Embodiment, For example, an inorganic filler and an organic filler can be used. Examples of the inorganic filler added to the second base material layer 22 include silica, talc, barium sulfate, calcium carbonate, aluminum hydroxide, aluminum oxide, magnesium hydroxide, magnesium oxide, mica, and zinc stearate. Moreover, as an organic filler added to the 2nd base material layer 22, a silicone resin type filler, a fluororesin type filler, a polybutadiene resin type filler etc. are mentioned, for example.
These fillers may be used individually by 1 type, and may be used in combination of 2 or more type.

The average particle diameter (number average diameter) of the filler used for the second base material layer 22 is preferably in the range of 10 μm to 50 μm.
When the average particle diameter of the filler used for the second base material layer 22 is less than 10 μm, there is a risk that the effects (blocking suppression effect, etc.) described later by adding the filler to the second base material layer 22 will be insufficient. .
On the other hand, when the average particle diameter of the filler used for the second base material layer 22 is larger than 50 μm, the number of filler particles decreases, and therefore, the softness unevenness easily occurs in the second base material layer 22, and the double-sided pressure-sensitive adhesive tape 10. When affixing to a to-be-adhered body which has a curved surface part and an unevenness | corrugation, there exists a possibility that the followable | trackability of the double-sided adhesive tape 10 may fall. In addition, when the average particle diameter of the filler used for the second base material layer 22 is larger than 50 μm, the height at which the filler protrudes from the surface of the second base material layer 22 is increased. When the pressure-sensitive adhesive layers 31 and 32 having a thickness of 2 μm or more and 200 μm or less are provided on the surface, the protruding portion of the filler may be defective, and the pressure-sensitive adhesive layers 31 and 32 may not be applied or transferred uniformly.

The amount of filler added to the second base material layer 22 is preferably in the range of 1 wt% to 10 wt% with respect to the ethylene-vinyl acetate copolymer constituting the second base layer 22. More preferably, it is in the range of not less than 8% by weight.
When the addition amount of the filler in the 2nd base material layer 22 is less than 1 weight%, there exists a possibility that the effect mentioned later by adding a filler to the 2nd base material layer 22 may become inadequate.
Moreover, when the addition amount of the filler in the 2nd base material layer 22 exceeds 10%, the 2nd base material layer 22 tends to become hard and there exists a possibility that the softness | flexibility of the double-sided adhesive tape 10 may fall. In this case, when the double-sided pressure-sensitive adhesive tape 10 is attached to an adherend having a curved surface or irregularities, the followability of the double-sided pressure-sensitive adhesive tape 10 may be reduced.

(Thicknesses of the first base material layer 21 and the second base material layer 22)
The thickness d1 of the first base material layer 21 varies depending on the VA% of the first base material layer 21 and the thickness d2 and VA% of the second base material layer 22, but is in the range of 30 μm to 300 μm, for example. It is preferable. When the thickness d1 of the first base material layer 21 is thinner than 30 μm, the flexibility of the base material 20 tends to be low, and the followability of the double-sided pressure-sensitive adhesive tape 10 tends to be low. Moreover, when thickness d1 of the 1st base material layer 21 is thicker than 300 micrometers, there exists a possibility that the punching characteristic of the double-sided adhesive tape 10 containing the base material 20 may fall. In addition, the thickness of the double-sided pressure-sensitive adhesive tape 10 tends to increase, and it is difficult to reduce the thickness of an electronic device such as a mobile phone terminal using the double-sided pressure-sensitive adhesive tape 10.

Further, the thickness d2 of each second base material layer 22 varies depending on the filler content in the second base material layer 22, the average particle diameter and VA%, the thickness d1 of the first base material layer 21, and the like. For example, it is preferable to be in the range of 10 μm to 100 μm. When the thickness d2 of the second base material layer 22 is thinner than 10 μm, the height at which the filler protrudes from the surface of the second base material layer 22 is increased depending on the average particle diameter of the filler. When the adhesive layers 31 and 32 having a thickness of 2 μm or more and 200 μm or less are provided on the surface of the layer 22, there is a possibility that the protruding portion of the filler becomes a defect and the adhesive layers 31 and 32 cannot be uniformly applied or transferred. On the other hand, when the thickness d2 of the second base material layer 22 is thicker than 100 μm, the flexibility of the base material 20 is lowered, and the base material 20 may not be easily wound in the manufacturing process of the double-sided pressure-sensitive adhesive tape 10. In addition, the thickness of the double-sided pressure-sensitive adhesive tape 10 tends to increase, and it is difficult to reduce the thickness of an electronic device such as a mobile phone terminal using the double-sided pressure-sensitive adhesive tape 10.
In the base material 20 of the present embodiment, the thicknesses d2 of the two second base material layers 22 may be the same or different from each other.

Furthermore, in the double-sided pressure-sensitive adhesive tape 10 of the present embodiment, the ratio (d1: d2) between the thickness d1 of the first base material layer 21 and the thickness d2 of each second base material layer 22 is 1: 4 to It is preferable to be in the range of 4: 1.
When the thickness d1 of the first base material layer 21 with respect to the thickness d2 of the second base material layer 22 is thicker than the above-described range, the ratio of the first base material layer 21 that does not include the filler in the base material 20 is relatively Get higher. In this case, in the processing step after the manufacture of the double-sided pressure-sensitive adhesive tape 10, when the double-sided pressure-sensitive adhesive tape 10 is punched into a desired shape, the base material 20 sticks to a blade or mold used for punching and the base material 20 extends. There is a fear. In other words, there is a possibility that the punching characteristics of the double-sided pressure-sensitive adhesive tape 10 including the base material 20 may deteriorate.

  On the other hand, when the thickness d1 of the first base material layer 21 with respect to the thickness d2 of the second base material layer 22 is thinner than the above-described range, the ratio of the second base material layer 22 containing the filler in the base material 20 is Relatively high. In this case, the flexibility of the double-sided pressure-sensitive adhesive tape 10 is likely to be reduced, and the followability of the double-sided pressure-sensitive adhesive tape 10 may be reduced when the double-sided pressure-sensitive adhesive tape 10 is attached to an adherend having a curved surface or unevenness. In particular, when the VA% of the second base material layer 22 is made lower than the VA% of the first base material layer 21 in order to further suppress the occurrence of blocking when winding the base material 20, for example, the second base material layer 22 Since this tends to become hard, such problems are likely to occur.

In addition, the total thickness of the base material 20 including the first base material layer 21 and the two second base material layers 22 is not particularly limited. When used for fixing the surface plate to the housing of the telephone terminal, it is preferably in the range of 50 μm to 500 μm, and more preferably in the range of 80 μm to 200 μm.
When the total thickness of the base material 20 is 50 μm or less, performance such as waterproofness and impact resistance by the double-sided pressure-sensitive adhesive tape 10 may be insufficient. Moreover, when the total thickness of the base material 20 exceeds 500 micrometers, the thickness of the double-sided adhesive tape 10 tends to become thick, and it becomes difficult to make a mobile phone terminal thin.

  In addition, the base material 20 of the present embodiment may be obtained by subjecting the surface (in this example, the surface of the second base material layer 22) to surface processing such as corona treatment or plasma treatment. In addition, an anchor coating agent may be applied to the surface.

(Adhesive layers 31, 32)
The adhesive layers 31 and 32 are made of an adhesive. Although the kind of adhesive which comprises the adhesion layers 31 and 32 is not specifically limited, For example, an acrylic adhesive, a silicone adhesive, a urethane adhesive, an ether adhesive, a rubber adhesive, etc. Can be used. Moreover, you may use a hot-melt type adhesive as an adhesive which comprises the adhesion layers 31 and 32. FIG. Among these pressure-sensitive adhesives, in consideration of heat resistance, environmental resistance, cost, etc., it is preferable to use an acrylic pressure-sensitive adhesive as the pressure-sensitive adhesive constituting the pressure-sensitive adhesive layers 31 and 32, ethyl acrylate (EA), It is more preferable to use an acrylic pressure-sensitive adhesive mainly composed of butyl acrylate (BA), 2-ethylhexyl acrylate (2-EHA) or the like.
The pressure-sensitive adhesive constituting the pressure-sensitive adhesive layer 31 and the pressure-sensitive adhesive constituting the pressure-sensitive adhesive layer 32 may be the same type or different types.

  The pressure-sensitive adhesive used for the pressure-sensitive adhesive layers 31 and 32 may be a cross-linked type or an uncross-linked type, and can be appropriately selected according to the use and purpose of the double-sided pressure-sensitive adhesive tape 10. . However, from the viewpoint of environmental resistance (light resistance, etc.) of the double-sided pressure-sensitive adhesive tape 10 and from the viewpoint of suppressing peeling and displacement of the double-sided pressure-sensitive adhesive tape 10, it is preferable to use a cross-linking type pressure-sensitive adhesive.

  Although the thickness of the adhesion layers 31 and 32 is not specifically limited, It is preferable to set it as the range of 2 micrometers or more and 200 micrometers or less, respectively. When the thickness of the adhesion layers 31 and 32 is less than 2 micrometers, the adhesive force of the double-sided adhesive tape 10 by the adhesion layers 31 and 32 tends to become low. In addition, when the thickness of the adhesive layers 31 and 32 is thicker than 200 μm, the double-sided adhesive tape 10 tends to be thick, and when the double-sided adhesive tape 10 is used for an electronic device such as a mobile phone as described later, There is a risk that miniaturization becomes difficult.

Moreover, the adhesion layers 31 and 32 may be colorless or may be colored such as black or white. The adhesive layers 31 and 32 may be transparent (light transmissive) or opaque (light non-transmissive). A method of coloring the adhesive layers 31 and 32 is not particularly limited, and examples thereof include a method of mixing a colorant, a pigment, a dye, and the like with the adhesive.
Moreover, you may mix additives, such as anti-aging agent, in the adhesion layers 31 and 32 as needed.

(Release liners 51 and 52)
As the release liners 51 and 52, a film made of paper, polyethylene, polypropylene, polyethylene terephthalate, or the like, which has been subjected to a release treatment for improving the releasability from the adhesive layers 31 and 32 can be used. Although it does not specifically limit as a material used for the peeling process of the release liners 51 and 52 of this Embodiment, For example, materials, such as a fluoro silicone, a long-chain alkyl vinyl monomer polymer, an amino alkyd type resin, can be used.
The thickness of the release liners 51 and 52 is not particularly limited, but is usually in the range of 25 μm to 125 μm, for example.

[How to use double-sided adhesive tape 10]
Then, an example of the usage method of the double-sided adhesive tape 10 of this Embodiment is demonstrated. FIG. 2 is a view showing an example of how to use the double-sided pressure-sensitive adhesive tape 10.
Display parts of electronic devices such as mobile phones, digital cameras, smartphones, e-books, etc., have become smaller and more complicated with the downsizing of electronic devices, and can be easily processed into any shape by punching. Possible double-sided adhesive tapes are often used. The double-sided adhesive tape 10 of this Embodiment is used for the electronic device which has such a display device, for example.
Specifically, as shown in FIG. 2, the electronic device 1 is provided with a display device 3 such as a liquid crystal display element or an organic EL display element inside a housing 2, and a light-transmitting material such as an acrylic plate or a glass plate. The surface plate 4 having the property is attached to the housing 2 so as to cover the display device 3. The double-sided pressure-sensitive adhesive tape 10 according to the present embodiment is formed in a frame shape along the periphery of the housing 2 and is used for fixing the surface plate 4 to the housing 2.

In general, a double-sided pressure-sensitive adhesive tape used for an electronic device or the like having a display device is required to have the following characteristics in addition to the adhesiveness for fixing the surface plate.
That is, the double-sided pressure-sensitive adhesive tape is required to be waterproof to prevent liquid such as water from entering the inside of the electronic device from between the surface plate and the housing. Further, the double-sided pressure-sensitive adhesive tape is required to have a step following ability to follow the unevenness and the step caused by decorative printing applied to the surface plate, molding variation of the housing, and the like. Furthermore, the double-sided adhesive tape absorbs the impact resistance that is not damaged even when an impact force is applied to the surface plate and absorbs the impact force applied to the surface plate, thereby damaging the surface plate and display device. Suppressing shock absorption is required. Furthermore, the double-sided pressure-sensitive adhesive tape is required to have punching characteristics for forming into a frame shape (frame shape) by punching.

  Conventionally, as a double-sided pressure-sensitive adhesive tape for fixing a surface plate in an electronic device or the like, a double-sided pressure-sensitive adhesive tape having a base material made of a resin foam in which bubbles are formed is used.

By the way, since the display part of electronic devices, such as a mobile phone and a smart phone, is increasing in size in recent years, the width | variety of the frame-type adhesive tape used in order to fix a surface plate in an electronic device is narrow. There is a tendency to become. Specifically, it may be required to reduce the width of the double-sided pressure-sensitive adhesive tape to 1 mm or even less than 1 mm.
Here, in the resin foam used as the base material of the double-sided pressure-sensitive adhesive tape, bubbles having a diameter of 0.5 mm or more may exist, and such bubbles are continuously formed in the width direction of the double-sided pressure-sensitive adhesive tape. In such a case, a through-hole penetrating the substrate in the width direction may be formed. And when a through-hole is formed in the base material of a double-sided adhesive tape, there exists a possibility that a liquid may permeate into the inside of an electronic device through this, and the waterproofness of an electronic device may fall.

  In a double-sided pressure-sensitive adhesive tape using a resin foam as a base material, it is necessary to make the width of the double-sided pressure-sensitive adhesive tape larger than twice the bubble diameter in order to guarantee waterproofness. However, when considering the variation in the lot and quality of the base material, it is confirmed that the maximum diameter of the bubbles is less than 0.5 mm over the entire width and length of the base material, and that all the formed bubbles are closed cells. There is currently no substrate made of a resin foam with a guaranteed percentage. For this reason, as long as the resin foam is used as the base material of the double-sided pressure-sensitive adhesive tape, the double-sided pressure-sensitive adhesive tape cannot sufficiently meet the demand for processing and using it in a narrow width of 1 mm or less than 1 mm. . Under such circumstances, when a resin foam is used as the base material of the double-sided pressure-sensitive adhesive tape, there may be a problem in increasing the size of the display unit in the electronic device.

On the other hand, in the double-sided pressure-sensitive adhesive tape 10 of the present embodiment, as described above, the first base material layer 21 and the second base material layer 22 of the base material 20 are both composed of an elastomer non-foamed material. . That is, in the first base material layer 21 and the second base material layer 22 of the present embodiment, unlike the case where the base material 20 is made of a foam, there is a possibility that a through hole penetrating the base material 20 is formed. Absent.
Thereby, as for the double-sided adhesive tape 10 of this Embodiment, the waterproofness is excellent compared with the case where the base material 20 is comprised from a foam. And when the double-sided adhesive tape 10 of this Embodiment is used for the electronic device 1 as mentioned above, liquids, such as water, infiltrate into the electronic device 1 from between the surface plate 4 and the housing | casing 2. Is suppressed.

  In particular, in the double-sided pressure-sensitive adhesive tape 10 of the present embodiment, unlike the case where a foam is used as the substrate 20, for example, even when the width of the double-sided pressure-sensitive adhesive tape 10 is as small as 0.3 mm to 0.7 mm, it is waterproof. The decline in sex is suppressed. Thereby, the double-sided adhesive tape 10 of this Embodiment can contribute to the enlargement of the display screen in the electronic device 1. FIG.

Moreover, in the double-sided pressure-sensitive adhesive tape 10 of the present embodiment, the first base material layer 21 and the second base material layer 22 of the base material 20 are both elastomers whose main component is a highly flexible ethylene-vinyl acetate copolymer. It is comprised by.
Thereby, the double-sided adhesive tape 10 of this Embodiment has the outstanding level | step difference followable | trackability. For example, even if the object to be coated with the double-sided pressure-sensitive adhesive tape 10 has unevenness due to decorative printing applied to the surface plate 4 or molding variations in the housing 2, the double-sided pressure-sensitive adhesive tape 10 follows the unevenness. The adhesion between the housing 2 and the surface plate 4 in the electronic device 1 is improved. Furthermore, the adhesiveness between the housing 2 and the surface plate 4 is improved by the double-sided pressure-sensitive adhesive tape 10, so that the penetration of liquid into the electronic device 1 is further suppressed, and the waterproofness of the electronic device 1 is enhanced.

Furthermore, in the double-sided pressure-sensitive adhesive tape 10 of the present embodiment, the first base material layer 21 and the second base material layer 22 are both composed of an elastomer whose main component is a highly flexible ethylene-vinyl acetate copolymer. This improves the shock resistance and shock absorption of the double-sided pressure-sensitive adhesive tape 10. For example, when the double-sided pressure-sensitive adhesive tape 10 is used in the electronic device 1, it becomes possible to absorb the impact applied to the electronic device 1 with the double-sided pressure-sensitive adhesive tape 10, and suppress damage to the surface plate 4 of the electronic device 1. can do.
In particular, when the first base material layer 21 has no filler and the VA% of the first base material layer 21 is larger than the VA% of the second base material layer 22, the first base material layer 21 is the second base layer 21. It becomes softer than the material layer 22. In this case, for example, the impact applied to the electronic device 1 is more easily absorbed by the first base material layer 21 of the base material 20. Thereby, the impact resistance and shock absorption of the double-sided pressure-sensitive adhesive tape 10 become better.

  In addition, the electronic device in which the double-sided adhesive tape 10 of this Embodiment is used is not restricted to what was mentioned above, It can use suitably for fixation of the components in the electronic device etc. which require other waterproofness. There are no particular limitations on the types of such electronic devices, for example, portable communication terminals such as mobile phone terminals and smartphones, portable recording devices such as digital cameras and video cameras, portable music playback devices, portable televisions, It can be used for all electronic devices such as notebook personal computers, portable game machines, electronic dictionaries, and electronic books. It can also be used for outdoor installation type display devices.

[Production method of double-sided adhesive tape 10]
Then, an example of the manufacturing method of the double-sided adhesive tape 10 of this Embodiment is demonstrated. The double-sided pressure-sensitive adhesive tape 10 of the present embodiment has a step of producing a base material 20 having a first base material layer 21 and a second base material layer 22, and adhesive layers 31 and 32 are formed on the base material 20. And obtaining the adhesive tape 10.

(Preparation of the base material 20)
The substrate 20 of the present embodiment can be manufactured by a melt extrusion molding method in which a resin that is a material of the substrate 20 is melted at a high temperature, extruded from a slit-like extrusion port of an extruder, and wound after cooling.
Specifically, first, a molten material (an ethylene-vinyl acetate copolymer containing a filler) serving as a material for the second base material layer 22, and a molten material (ethylene-vinyl acetate) serving as a material for the first base material layer 21. Copolymer) and a molten material as a material of the second base material layer 22 are extruded together from three extrusion ports formed in the extrusion die, thereby obtaining a laminate in which these molten materials are sequentially laminated. And after solidifying the obtained laminated body by air cooling, the base material by which the 2nd base material layer 22, the 1st base material layer 21, and the 2nd base material layer 22 were laminated | stacked in this order by winding up 20 is obtained.

Here, in the melt extrusion molding method, there are a T-die method in which the extrusion port is a straight (flat) shape, an inflation method in which the extrusion port is in a ring shape, and the like, depending on the type of die for extruding the molten material. For example, in the case of the inflation method, the molten material is extruded into a cylindrical shape, air is blown into the extruded cylindrical molten material, the molten material is expanded by air pressure, and then cooled by air. Then, the base material 20 is obtained by opening the obtained cylindrical film and winding it into a flat film. In the case of the inflation method, when the cylindrical film is cut open, it is possible to simultaneously manufacture the two base materials 20 by cutting them at two opposing positions.
In addition, the manufacturing method of the base material 20 is not restricted to the method mentioned above, A well-known method can be employ | adopted without a problem.

(Production of double-sided adhesive tape 10)
Then, an example of the method of producing the double-sided adhesive tape 10 using the obtained base material 20 is demonstrated.
First, the pressure-sensitive adhesive is applied to the release treatment surface of the release liner 51 and dried to form the pressure-sensitive adhesive layer 31. The method for applying the pressure-sensitive adhesive is not particularly limited, and known methods such as a dip coating method, a roll coating method, a curtain coating method, a die coating method, and a slit coating method can be employed. Then, the base material 20 mentioned above is unwound and laminated | stacked on the obtained adhesion layer 31, and the laminated body by which the peeling liner 51, the adhesion layer 31, and the base material 20 were laminated | stacked is obtained.

In addition, the pressure-sensitive adhesive is similarly applied to the release treatment surface of the other release liner 52 and dried to form the pressure-sensitive adhesive layer 32. And on the obtained adhesion layer 32, the said laminated body is laminated | stacked so that the base material 20 and the adhesion layer 32 may contact | connect.
Then, the double-sided adhesive tape 10 which has the laminated structure shown in FIG. 1 is obtained by heating and curing as needed.

Moreover, the following method is mentioned as another method of producing the double-sided adhesive tape 10. FIG.
First, the pressure-sensitive adhesive is applied to the release treatment surface of the release liner 51 and dried to form the pressure-sensitive adhesive layer 31. Then, the base material 20 mentioned above is laminated | stacked on the obtained adhesion layer 31, and the laminated body by which the peeling liner 51, the adhesion layer 31, and the base material 20 were laminated | stacked is obtained.
Next, a pressure-sensitive adhesive is applied to the surface of the laminate 20 obtained on the side opposite to the pressure-sensitive adhesive layer 31 and dried to form the pressure-sensitive adhesive layer 32. Then, the release liner 52 is laminated | stacked on the adhesion layer 32, and the double-sided adhesive tape 10 which has the laminated structure shown in FIG. 1 is obtained by heating and curing as needed.

Furthermore, the following method is mentioned as another method of producing the double-sided pressure-sensitive adhesive tape 10.
First, the pressure-sensitive adhesive is applied and dried on the second base material layer 22 of the base material 20 to form the pressure-sensitive adhesive layer 31. Subsequently, a release liner 51 is laminated on the formed pressure-sensitive adhesive layer 31 to obtain a laminate in which the release liner 51, the pressure-sensitive adhesive layer 31, and the substrate 20 are laminated.
Next, a pressure-sensitive adhesive is applied to the surface of the laminate 20 obtained on the side opposite to the pressure-sensitive adhesive layer 31 and dried to form the pressure-sensitive adhesive layer 32. Then, the release liner 52 is laminated | stacked on the adhesion layer 32, and the double-sided adhesive tape 10 which has the laminated structure shown in FIG. 1 is obtained by heating and curing as needed.

Thus, in the production of the double-sided pressure-sensitive adhesive tape 10 of the present embodiment, the base material 20 wound up in the manufacturing process of the base material 20 is rewound and laminated on the pressure-sensitive adhesive layer 31, for example.
Here, in general, in a film made of a highly flexible material such as an ethylene-vinyl acetate copolymer, when the film is wound up and then stored for a long period of time, so-called blocking occurs in which the overlapping films adhere to each other. Cheap. And it is difficult to rewind the film which produced blocking, and it is difficult to manufacture an adhesive tape using such a film.

In contrast, in the present embodiment, the second base material layer 22 provided on the surface of the base material 20 contains a filler and has an ethylene-vinyl acetate copolymer weight of VA% of 11% by weight to 20% by weight. It is comprised from the non-foamed material of the elastomer which has coalescence as a main component. And in the manufacturing process of the base material 20, the base material 20 is wound up so that 2nd base material layers 22 formed in the surface of the base material 20 may overlap.
Thereby, in the manufacturing process of the double-sided pressure-sensitive adhesive tape 10 of the present embodiment, the base material 20 (first base material layer 21 and second base material layer 22) is an elastomer whose main component is an ethylene-vinyl acetate copolymer. Even when it is made of a highly flexible material such as non-foamed material, the occurrence of blocking is suppressed.

Specifically, the second base material layer 22 contains a filler, thereby having an appropriate flexibility derived from the ethylene-vinyl acetate copolymer, an antiblocking property derived from the filler, and an appropriate hardness. Will have. Thereby, even if it is a case where 2nd base material layers 22 are laminated | stacked by winding up the base material 20, generation | occurrence | production of blocking is suppressed. In other words, the double-sided pressure-sensitive adhesive tape 10 of the present embodiment has good blocking resistance.
As a result, for example, even when the wound base material 20 is stored for a long period of time, the base material 20 can be rewound in the production process of the double-sided pressure-sensitive adhesive tape 10, and the double-sided pressure-sensitive adhesive tape 10 described above can be obtained. it can.

And the double-sided adhesive tape 10 obtained by the method mentioned above is used by being punched into a desired shape, if necessary.
In the present embodiment, the second base material layer 22 is made of an elastomer non-foamed material containing a filler and having an VA% of 11% by weight or more and 20% by weight or less of an ethylene-vinyl acetate copolymer as a main component. By comprising, the 2nd base material layer 22 has moderate hardness as mentioned above. Thereby, even if the 1st base material layer 21 does not have a filler, when punching out the double-sided adhesive tape 10, the base material 20 sticks to the blade used for punching, a type | mold, etc., and the base material 20 expands. Is suppressed. As a result, in this embodiment, the double-sided pressure-sensitive adhesive tape 10 is easily processed into a desired shape by punching. In other words, the double-sided pressure-sensitive adhesive tape 10 of the present embodiment has good punching characteristics.

  As described above, in the present embodiment, since the base material 20 has the above-described configuration, even when the base material 20 is narrowed for use in an electronic device or the like, a decrease in waterproofness is suppressed, and The double-sided pressure-sensitive adhesive tape 10 that is excellent in impact properties and shock absorption properties and excellent in flexibility, step following property, blocking resistance, and punching properties is realized.

<Embodiment 2>
In Embodiment 1 mentioned above, the base material 20 demonstrated the double-sided adhesive tape 10 which has the structure where the 2nd base material layer 22 was provided in the front and back both surfaces of the 1st base material layer 21. FIG. However, the structure of the base material 20 in the double-sided pressure-sensitive adhesive tape 10 is not limited to this. Next, a second embodiment of the present invention will be described.
FIG. 3 is a diagram showing a configuration of the double-sided pressure-sensitive adhesive tape 10 according to the second embodiment. In addition, about the structure similar to Embodiment 1, the same code | symbol is used and detailed description is abbreviate | omitted here.

  As shown in FIG. 3, in the double-sided pressure-sensitive adhesive tape 10 of the second embodiment, the base material 20 includes a first base material layer 21 and a second base material layer 22 laminated on one side of the first base material layer 21. have. That is, unlike Embodiment 1, the 2nd base material layer 22 is laminated | stacked only on one surface among the front and back of the 1st base material layer 21, and the adhesion layer 32 is directly on the other surface. Are stacked.

Also in the second embodiment, the base material 20 is a first base material layer 21 made of an elastomer non-foamed material having an ethylene-vinyl acetate copolymer as a main component, and VA% is 11% by weight or more and 20% by weight or less. It is made of an elastomer non-foamed material mainly composed of an ethylene-vinyl acetate copolymer, and has a laminated structure with the second base material layer 22 containing a filler. Even in such a case, the double-sided pressure-sensitive adhesive tape 10 is realized, in which a decrease in waterproofness is suppressed, excellent in impact resistance and shock absorption, and excellent in flexibility, step followability, and punching characteristics.
In the double-sided pressure-sensitive adhesive tape 10 according to Embodiment 2, the first base material layer 21 preferably contains no filler.

  Moreover, when winding up the base material 20 in the manufacturing process of the double-sided pressure-sensitive adhesive tape 10, the first base material 20 is rolled up while another film such as a PET film is stacked on the first base material layer 21 side. Contact between the surface of the base material layer 21 and the surface of the second base material layer 22 is suppressed. Thereby, even if it is a case where the base material 20 of Embodiment 2 with which the 1st base material layer 21 and the 2nd base material layer 22 were laminated | stacked, generation | occurrence | production of blocking is suppressed.

Next, the present invention will be described more specifically based on examples. However, the present invention is not limited to the following examples.
The present inventor made the base material 20 in which the second base material layer 22 was laminated on both front and back surfaces of the first base material layer 21, and the double-sided pressure-sensitive adhesive tape 10 having the base material 20, The double-sided pressure-sensitive adhesive tape 10 was evaluated.

1. Production of double-sided adhesive tape 10 (Example 1)
The base material 20 in which the second base material layer 22 was laminated on both the front and back surfaces of the first base material layer 21 was produced by the melt extrusion molding method described above. Specifically, ethylene having a VA% of 15% by weight is formed on both the front and back surfaces of the first base material layer 21 made of an elastomer non-foamed material having an VA% of 25% by weight of an ethylene-vinyl acetate copolymer as a main component. A second base material comprising a non-foamed elastomer having a vinyl acetate copolymer as a main component and a silica-based filler having an average particle diameter of 32.5 μm added to the ethylene-vinyl acetate copolymer in an amount of 5% by weight. A base material 20 having a three-layer structure in which the layers 22 were laminated was produced.
Here, the ratio of the thickness d1 of the first base material layer 21 to the thickness d2 of the second base material layer 22 is d1: d2 = 3: 1, and the first base material layer 21 and the second base material layer The total thickness of the base material 20 combined with the layer 22 was 100 μm. That is, in the base material 20, the thickness d1 of the first base material layer 21 was 60 μm, and the thickness d2 of each second base material layer 22 was 20 μm.

  Subsequently, a pressure-sensitive adhesive solution in which 1.5 parts by weight of an isocyanate-based crosslinking agent (manufactured by Syden Chemical Co., Ltd., AL) is added to 100 parts by weight of an acrylic pressure-sensitive adhesive solution (manufactured by Syden Chemical Co., Ltd., AT-D54) Then, it was coated on a PET release liner 51 (thickness: 50 μm) by a doctor coater and dried at about 110 ° C. for 3 minutes to form an adhesive layer 31 having a thickness of 50 μm.

Next, the produced base material 20 was bonded onto the adhesive layer 31 formed on the release liner 51.
Subsequently, the adhesive layer 32 having a thickness of 50 μm was formed by applying an adhesive solution onto a PET release liner 52 (thickness of 50 μm) and drying the same as the adhesive layer 31.
And the double-sided adhesive tape 10 by which the adhesion layer 31, the base material 20, and the adhesion layer 32 were laminated | stacked by bonding the adhesion layer 32 on the base material 20 bonded on the adhesion layer 31 was obtained.

(Example 2)
A double-sided pressure-sensitive adhesive tape 10 was obtained in the same manner as in Example 1 except that the VA% of the second base material layer 22 was changed to 11% by weight.

(Example 3)
A double-sided pressure-sensitive adhesive tape 10 was obtained in the same manner as in Example 1 except that the VA% of the second base material layer 22 was changed to 20% by weight.

Example 4
A double-sided pressure-sensitive adhesive tape 10 was obtained in the same manner as in Example 1 except that the VA% of the first base material layer 21 was changed to 0.5% by weight.

(Example 5)
A double-sided pressure-sensitive adhesive tape 10 was obtained in the same manner as in Example 1 except that the VA% of the first base material layer 21 was 41% by weight.

(Example 6)
A double-sided pressure-sensitive adhesive tape 10 was obtained in the same manner as in Example 1 except that the content of the filler in the second base material layer 22 in the base material 20 was 1% by weight.

(Example 7)
In the base material 20, the double-sided pressure-sensitive adhesive tape 10 was obtained in the same manner as in Example 1 except that the filler content in the second base material layer 22 was changed to 2% by weight.

(Example 8)
In the base material 20, the double-sided pressure-sensitive adhesive tape 10 was obtained in the same manner as in Example 1 except that the filler content in the second base material layer 22 was changed to 10% by weight.

Example 9
A double-sided pressure-sensitive adhesive tape 10 was obtained in the same manner as in Example 1 except that the content of the filler in the second base material layer 22 was 11 wt%.

(Comparative Example 1)
A double-sided pressure-sensitive adhesive tape 10 was obtained in the same manner as in Example 1 except that the VA% of the second base material layer 22 was changed to 10% by weight.

(Comparative Example 2)
A double-sided pressure-sensitive adhesive tape 10 was obtained in the same manner as in Example 1 except that the VA% of the second substrate layer 22 was changed to 21% by weight.

(Comparative Example 3)
Double-sided pressure-sensitive adhesive tape in the same manner as in Example 1 except that the second base material layer 22 of the base material 20 was formed of an elastomer non-foamed material mainly composed of an ethylene-vinyl acetate copolymer containing no filler. 10 was obtained.

2. Evaluation method Subsequently, the evaluation method of the base material 20 and the double-sided adhesive tape 10 is demonstrated.
(1) Step following ability test The double-sided pressure-sensitive adhesive tape 10 obtained in Examples 1 to 9 and Comparative Examples 1 to 3 is formed into a frame shape (see FIG. 2) having an outer diameter of 50 mm × 100 mm and a width of 0.7 mm. Punched out.
And the frame type double-sided adhesive tape 10 formed by punching was affixed to a rectangular polycarbonate plate having an outer shape of 60 mm × 125 mm.

Subsequently, the polycarbonate plate with the double-sided pressure-sensitive adhesive tape 10 attached thereon and the rectangular polycarbonate plate with an outer shape of 60 mm × 125 mm formed with a step of 25 μm height, The test piece was bonded so that the formed surface was on the inside, pressure-bonded with a load of 2 kg for 10 seconds, and then allowed to stand at 23 ° C. for 24 hours.
In addition, the level | step difference of a polycarbonate board was formed by affixing the single-sided tape which made the base material the polyethylene terephthalate (PET) of thickness 25 micrometers and width 5mm to a polycarbonate board.

Subsequently, the test piece was tested based on the IPX7 standard (JIS C 0920 / IEC 60529). Specifically, after leaving the test piece in 1 m deep water for 30 minutes, the test piece was taken out, and the presence or absence of water immersion inside the frame-type double-sided pressure-sensitive adhesive tape 10 was evaluated.
Further, the same test was performed with the height of the step formed on the polycarbonate plate being 50 μm.

The step following ability was evaluated according to the following criteria for each of the case where the step height was 25 μm and the case where the step height was 50 μm.
A: No water is seen inside the double-sided pressure-sensitive adhesive tape 10.
C: Water immersion inside the double-sided pressure-sensitive adhesive tape 10 is observed.

(2) Blocking test About each of Examples 1 to 9 and Comparative Examples 1 to 3, the lower winding part 25m in the raw material of the base material 20 wound in a roll shape was cut into a width of 25 mm. This roll-shaped substrate 20 was stored for a predetermined period (1, 3, 5, 7, 14, 31 days) under the conditions of a temperature of 50 ° C. and a humidity of 90%, taken out, and left at 23 ° C. for 24 hours. A test piece was used.
This test piece was rewound at a speed of 300 mm / min with a tensile tester (manufactured by Aiko Engineering Co., Ltd.), and evaluation was performed based on whether or not blocking occurred.
The blocking test was evaluated according to the following criteria.
A: Blocking is not seen.
B: Blocking is observed after the storage period of 14 days.
C: Blocking is observed after a storage period of less than 14 days.

(3) Punching processing characteristics The double-sided adhesive tape 10 obtained in Examples 1 to 9 and Comparative Examples 1 to 3 was used with a personal small punching machine (manufactured by Tester Sangyo Co., Ltd.). The punching characteristics were evaluated based on the number of successful punching operations when a punching process was performed 10 times on a frame mold having a width of 0.7 mm.
The punching characteristics were evaluated according to the following criteria.
A: The number of successful punching is 8 times or more.
B: Successful punching is 5 times or more and 7 times or less.
C: The number of successful punches is less than 5.

(4) Impact absorption test The double-sided pressure-sensitive adhesive tape 10 obtained in Examples 1 to 9 and Comparative Examples 1 to 3 was punched into a frame having an outer shape of 25 mm × 25 mm and a width of 0.7 mm, and an outer size of 50 mm × A test piece was sandwiched between two 50 mm square acrylic plates, loaded with a mass of 1 kg and left at 23 ° C. for 24 hours.
Subsequently, an iron ball having a mass of 16 g was dropped from a position having a height of 150 mm at the center of the test piece, and the impact force applied to the test piece was measured. For measuring the impact force, an accelerometer (2304A manufactured by Showa Sokki Co., Ltd.) was used, and the accelerometer was installed on the surface opposite to the surface on which the iron ball of the test piece was dropped.

4A is a diagram showing an example of an attenuation curve of acceleration measured by an accelerometer, and FIG. 4B is an enlarged view of the first wave of the attenuation curve shown in FIG. 4A. It is. As an evaluation of shock absorption, paying attention to the peak height of the first wave shown in FIG. 4B in the obtained acceleration decay curve, the lower the peak height, the more the shock is absorbed. It was evaluated as a thing.
In addition, when using the double-sided adhesive tape 10 for the electronic device 1 (refer FIG. 2) mentioned above, the numerical value of the peak height obtained by this test is a range in which 2200 or less is permitted.

3. Evaluation Results Table 1 shows the evaluation results for the double-sided pressure-sensitive adhesive tape 10 and the base material 20 of Examples 1 to 9. Moreover, it shows in Table 2 about the evaluation result with respect to the double-sided adhesive tape 10 and the base material 20 of Comparative Example 1- Comparative Example 3.

As shown in Table 1, in Examples 1 to 9, a base material 20 having good blocking resistance is obtained, and a double-sided pressure-sensitive adhesive tape 10 having good step following characteristics, punching characteristics, and shock absorption is provided. It was confirmed that it was obtained.
From the above, it has been confirmed that Examples 1 to 9 are suitable for use when, for example, the casing 2 and the surface plate 4 are bonded to each other in the electronic apparatus 1.

On the other hand, in Comparative Example 1 in which the VA% in the ethylene-vinyl acetate copolymer of the second base material layer 22 is 10% by weight, the height of the step is 25 μm as compared with Examples 1 to 9. It was confirmed that the step following ability was inferior in both cases of 50 μm and 50 μm.
This is considered to be because the VA% of the second base material layer 22 is low and the flexibility of the second base material layer 22 is low.

Further, in Comparative Example 2 in which the VA% in the ethylene-vinyl acetate copolymer of the second base material layer 22 is 21% by weight, compared with Examples 1 to 9, the blocking resistance and the punching process characteristics are improved. Inferiority was confirmed.
This is considered to be because VA% in the second base material layer 22 is high and the second base material layer 22 is excessively soft.

  Furthermore, in the comparative example 3 in which the 2nd base material layer 22 does not contain a filler, compared with Example 1- Example 9, blocking resistance is low, and when the base material 20 is wound up, it is easy to block. It was confirmed.

Moreover, comparing Example 1 to Example 5 in which the VA% of the first base material layer 21 among Examples 1 to 9 is different from each other, the VA% of the first base material layer 21 is 0.5 weight. In Example 4, the step following ability (step height 50 μm) is inferior compared with Examples 1 to 3 and Example 5 in which VA% of the first base material layer 21 is 1% by weight or more. Was confirmed.
On the other hand, in Example 5 in which the VA% of the first base material layer 21 is 41% by weight, punching is performed as compared with Examples 1 to 4 in which the VA% of the first base material layer 21 is 40% by weight or less. It was confirmed that the characteristics were inferior.
Therefore, it was confirmed that the VA% of the first base material layer 21 is more preferably in the range of 1% by weight to 41% by weight.

Furthermore, when Example 1 and Examples 6 to 9 in which the content of the filler in the second base material layer 22 among Examples 1 to 9 is different from each other are compared, the content of the filler is 1% by weight. In Example 6, it was confirmed that the blocking properties were inferior to those in Examples 1 and 7 to 9 in which the filler content was 2% by weight or more.
Further, in Example 9 in which the filler content is 11% by weight, compared with Example 1 and Examples 6 to 8 in which the filler content is 10% by weight or less, the step following property (step height) 50 μm) was confirmed to be inferior.
Therefore, it was confirmed that the filler content in the second base material layer 22 is more preferably in the range of 2 wt% to 10 wt%.

DESCRIPTION OF SYMBOLS 10 ... Double-sided adhesive tape, 20 ... Base material, 21 ... 1st base material layer, 22 ... 2nd base material layer, 31, 32 ... Adhesive layer, 51, 52 ... Release liner

Claims (7)

A substrate;
An adhesive layer laminated on both sides of the base material,
The substrate is
A first base material layer made of an elastomer non-foamed material mainly composed of an ethylene / vinyl acetate copolymer;
The filler is made of an elastomer non-foamed body, the main component of which is an ethylene / vinyl acetate copolymer having a vinyl acetate content (VA%) of 11 wt% or more and 20 wt% or less, which is laminated on the first base material layer. A double-sided pressure-sensitive adhesive tape comprising: a second base material layer comprising:   2. The double-sided pressure-sensitive adhesive tape according to claim 1, wherein the first base material layer has a VA% of 1 wt% or more and 40 wt% or less.   The double-sided pressure-sensitive adhesive tape according to claim 1 or 2, wherein the filler contained in the second base material layer has an average particle diameter of 10 µm or more and 50 µm or less.   The filler content in the second base material layer is 2 wt% or more and 10 wt% or less with respect to the elastomer constituting the second base material layer. Double-sided pressure-sensitive adhesive tape according to item.   The ratio of the thickness of the first base material layer to the thickness of the second base material layer is in the range of 1: 4 to 4: 1. Double-sided adhesive tape.   The double-sided pressure-sensitive adhesive tape according to claim 1, wherein the second base material layer is laminated on both surfaces of the first base material layer. A first base material layer made of an elastomer non-foamed material mainly composed of an ethylene / vinyl acetate copolymer;
It is laminated on both surfaces of the first base material layer, and is composed of an elastomer non-foamed material mainly composed of an ethylene / vinyl acetate copolymer having a vinyl acetate content (VA%) of 11% by weight to 20% by weight. And a second base material layer containing a filler,
A base material for a double-sided pressure-sensitive adhesive tape, which is wound up in a roll shape.

Images