JP2017119777A - Double-sided adhesive tape - Google Patents

Abstract

A double-sided pressure-sensitive adhesive tape that can be peeled off by being stretched after being attached to an adherend, and has good pullability from the adherend when peeled off, and impact is applied to the adherend during normal bonding. An object of the present invention is to provide a double-sided pressure-sensitive adhesive tape having good impact resistance.
A double-sided pressure-sensitive adhesive tape includes a base material made of polyurethane, and a first pressure-sensitive adhesive layer and a second pressure-sensitive adhesive layer laminated on both surfaces of the base material, respectively. At least one of the agent layer 3 and the second pressure-sensitive adhesive layer 4 includes a styrene-isoprene-styrene block copolymer, a process oil made of petroleum hydrocarbon, an aliphatic hydrocarbon resin, and an aliphatic aromatic hydrocarbon. And a tackifying resin containing at least one selected from a resin and a hydrogenated hydrocarbon resin.
[Selection] Figure 1

Description

  The present invention relates to a double-sided pressure-sensitive adhesive tape.

Conventionally, as an adhesive tape, there is an adhesive tape that can be stretched and peeled off from an adherend by stretching.
For example, Patent Document 1 discloses an adhesive sheet that is pressure-sensitive adhesive on both sides and can be re-peeled by pulling it in the direction of the adhesive surface with a grip tab. Furthermore, Patent Document 2 discloses an adhesive tape that contains a pressure-sensitive adhesive and can be removed by stretching after bonding to a substrate.

JP 2002-235046 A Japanese Patent No. 567148

By the way, for example, a battery of a mobile terminal such as a mobile phone or a smartphone may be removed from the casing of the mobile terminal when the battery is replaced, and both surfaces are peelable by stretching for the purpose of fixing the battery to the casing of the mobile terminal. Adhesive tape may be used. Here, the mobile terminal may fall due to carelessness of the user, and in this case, the battery may be impacted by the drop impact or the battery may be detached from the housing.
The present invention is a double-sided pressure-sensitive adhesive tape that can be peeled off by being stretched after being attached to an adherend, and has good pullability from the adherend when peeled, and an impact is applied to the adherend during normal bonding. An object of the present invention is to provide a double-sided pressure-sensitive adhesive tape having good impact resistance.

The double-sided pressure-sensitive adhesive tape of the present invention comprises a base material made of polyurethane and a pressure-sensitive adhesive layer laminated on each of both surfaces of the base material, and at least one of the pressure-sensitive adhesive layers is a styrene-isoprene-styrene block copolymer. A polymer, a process oil made of petroleum hydrocarbon, and a tackifying resin containing at least one selected from aliphatic hydrocarbon resins, aliphatic aromatic hydrocarbon resins, and hydrogenated hydrocarbon resins. It is characterized by.
Here, the styrene-isoprene-styrene block copolymer has a styrene content in the range of 14 wt% to 25 wt%, and a styrene-isoprene block amount of 12 wt% to 25 wt%. Can be a feature.
The styrene-isoprene-styrene block copolymer may have a linear molecular structure.

  According to the present invention, it is a double-sided pressure-sensitive adhesive tape that can be peeled off by being stretched after being attached to an adherend, and has good pullability from the adherend when peeled off, and impacts the adherend during normal bonding. It is possible to provide a double-sided pressure-sensitive adhesive tape having good impact resistance when added.

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 the use condition of the double-sided adhesive tape to which this Embodiment is applied. (A)-(c) is the figure which showed the state which pulls out the double-sided adhesive tape to which this Embodiment is applied.

Embodiments of the present invention will be described below.
[Configuration of double-sided adhesive tape 1]
FIG. 1 is a diagram illustrating an example of a configuration of a double-sided pressure-sensitive adhesive tape 1 to which the exemplary embodiment is applied. As shown in FIG. 1, the double-sided pressure-sensitive adhesive tape 1 of the present embodiment includes a base material 2, a first pressure-sensitive adhesive layer 3 as an example of a pressure-sensitive adhesive layer laminated on one surface of the base material 2, A second pressure-sensitive adhesive layer 4 as an example of a pressure-sensitive adhesive layer laminated on the other surface of the substrate 2 (the surface opposite to the surface on which the first pressure-sensitive adhesive layer 3 is laminated) is provided. Moreover, the double-sided pressure-sensitive adhesive tape 1 of the present embodiment is provided on each of the first pressure-sensitive adhesive layer 3 and the second pressure-sensitive adhesive layer 4, and on each of the first pressure-sensitive adhesive layer 3 and the second pressure-sensitive adhesive layer 4. Release liners 5 and 6 having releasability are provided.
In the description of the present embodiment, the state where the release liners 5 and 6 are peeled off (the laminated structure of the base material 2, the first pressure-sensitive adhesive layer 3, and the second pressure-sensitive adhesive layer 4) is referred to as a double-sided pressure-sensitive adhesive tape 1. There is.

  The double-sided pressure-sensitive adhesive tape 1 of the present embodiment is used to affix to two adherends by being attached to the two adherends. In addition, the double-sided pressure-sensitive adhesive tape 1 according to the present embodiment is used to fix two adherends and then pulled out from between the two adherends when it is no longer necessary to be fixed. Is peeled from one adherend.

More specifically, the double-sided pressure-sensitive adhesive tape 1 of the present embodiment includes, for example, a battery (first adherend) used for a mobile terminal such as a smartphone or a mobile phone, and a casing (second second) of the mobile terminal. Used to fix to the adherend).
Moreover, when the battery of a portable terminal is fixed to a housing | casing using the double-sided adhesive tape 1, a battery may be removed from a housing | casing for the purpose of reusing a battery, for example. Although details will be described later, when removing the battery from the casing of the mobile terminal, the double-sided adhesive tape 1 is stretched by pulling in a direction substantially parallel to the surface of the casing and the adherend of the double-sided adhesive tape 1. By doing so, the double-sided adhesive tape 1 is pulled out from between the housing and the battery. Thereby, the double-sided adhesive tape 1 is peeled from the casing and the battery, and the battery fixed to the casing by the double-sided adhesive tape 1 is removed from the casing. By removing the double-sided pressure-sensitive adhesive tape 1 in this way and removing the battery from the housing, it is possible to remove the battery without applying distortion to the battery when removing the battery.

Here, for example, the mobile terminal may be dropped due to carelessness of the user, the battery fixed to the casing of the mobile terminal is impacted by the impact at the time of dropping, or the mobile terminal body is damaged. There is a risk of doing so.
On the other hand, the double-sided pressure-sensitive adhesive tape 1 of the present embodiment has a property of reducing impact (impact resistance) when the base material 2, the first pressure-sensitive adhesive layer 3 and the second pressure-sensitive adhesive layer 4 have a configuration described later. ). When the double-sided pressure-sensitive adhesive tape 1 according to the present embodiment is used for fixing a battery to the casing of the mobile terminal, the double-sided pressure-sensitive adhesive tape 1 even when an impact is applied due to dropping of the mobile terminal or the like. Thus, the impact is reduced, and the detachment of the battery from the housing and the damage of the battery or the like are suppressed.

In the double-sided pressure-sensitive adhesive tape 1 of the present embodiment, the total thickness of the base material 2, the first pressure-sensitive adhesive layer 3, and the second pressure-sensitive adhesive layer 4 is preferably in the range of 100 μm to 250 μm. When the total thickness of the double-sided pressure-sensitive adhesive tape 1 is excessively thin, the effect of reducing impact tends to be insufficient. In this case, when an impact is applied to a portable terminal or the like in which the double-sided adhesive tape 1 is used, the impact may be applied to the casing or battery of the portable terminal. Moreover, the double-sided pressure-sensitive adhesive tape 1 may be peeled off from the casing of the portable terminal, the battery, or the like due to an impact, and the battery may be detached from the casing.
On the other hand, when the total thickness of the double-sided pressure-sensitive adhesive tape 1 is excessively thick, a mobile terminal using the double-sided pressure-sensitive adhesive tape 1 tends to be thick.

In the double-sided pressure-sensitive adhesive tape 1 of the present embodiment, the elongation is preferably in the range of 400% to 1200%, and more preferably in the range of 600% to 900%.
When the elongation percentage of the double-sided pressure-sensitive adhesive tape 1 is less than 400%, it becomes difficult to stretch the double-sided pressure-sensitive adhesive tape 1 and pull it out from between the adherends, or to pull out the double-sided pressure-sensitive adhesive tape 1 from between the adherends. There is a risk that the load on
On the other hand, when the elongation percentage of the double-sided pressure-sensitive adhesive tape 1 exceeds 1200%, the double-sided pressure-sensitive adhesive tape 1 is easily stretched when the double-sided pressure-sensitive adhesive tape 1 is pulled out from between the adherends. Can be difficult. Moreover, when pulling out the double-sided pressure-sensitive adhesive tape 1, a large space may be required. Thus, when the elongation rate of the double-sided pressure-sensitive adhesive tape 1 is out of the above range, workability may be reduced in the pulling out of the double-sided pressure-sensitive adhesive tape 1.
In the description of the present embodiment, the “elongation rate” of the double-sided pressure-sensitive adhesive tape 1 means the elongation at break measured by a method defined in JIS K 6767.

  Moreover, it is preferable that the double-sided adhesive tape 1 does not have a yield point in the stress-strain curve measured by the method prescribed | regulated by JISK6767. When the double-sided pressure-sensitive adhesive tape 1 is pulled out from between the adherends, the double-sided pressure-sensitive adhesive tape 1 does not transmit the force applied when the double-sided pressure-sensitive adhesive tape 1 is stretched in the pulling direction. It is easy to be concentrated and transmitted to a predetermined area (X portion shown in FIGS. 2 and 3B described later). In this case, a necking phenomenon occurs, and the base material 2 may be cut before the double-sided pressure-sensitive adhesive tape 1 is completely pulled out from between the adherends.

Then, the structure of each layer of the double-sided adhesive tape 1 to which this Embodiment is applied is demonstrated in detail.
<Substrate 2>
The base material 2 in the double-sided pressure-sensitive adhesive tape 1 of the present embodiment is a so-called urethane base material made of polyurethane. By using a urethane-based substrate as the substrate 2, the substrate 2 is stretched when the double-sided pressure-sensitive adhesive tape 1 is pulled out from between the adherends. Accordingly, when the adhesive tape 1 is pulled out from between the adherends, the first adhesive layer 3 and the second adhesive layer 4 are easily stretched and peeled off from the adherend as the base material 2 is stretched. . That is, when the base material 2 undergoes deformation unique to polyurethane in the width direction and the thickness direction, the force applied when the double-sided pressure-sensitive adhesive tape 1 is stretched in the pulling direction causes the first pressure-sensitive adhesive layer 3 and the second pressure-sensitive adhesive layer. 4 is transmitted gently. As a result, the first pressure-sensitive adhesive layer 3 and the second pressure-sensitive adhesive layer 4 are gradually peeled off from the surfaces of the battery 12 and the housing 11 without being left behind while gradually narrowing in the width direction together with the base material 2. Go. As a result, the double-sided adhesive tape 1 can be easily pulled out from between the adherends.
In addition, the base material 2 may contain other components other than polyurethane as long as the effect of the double-sided pressure-sensitive adhesive tape 1 of the present embodiment and the stretchability at the time of pulling are not impaired. The base material which consists of another material with respect to 2 may be laminated | stacked by co-extrusion or bonding.

Moreover, the base material 2 of the present embodiment preferably has a thickness in the range of 30 μm to 200 μm, and more preferably in the range of 40 μm to 100 μm.
When the thickness of the base material 2 is less than 30 μm, the strength of the double-sided pressure-sensitive adhesive tape 1 decreases, and the double-sided pressure-sensitive adhesive tape 1 may be broken when the double-sided pressure-sensitive adhesive tape 1 is pulled out from between the adherends. Moreover, in the manufacturing process of the double-sided pressure-sensitive adhesive tape 1, wrinkles or the like may occur in the base material 2.
On the other hand, when the thickness of the base material 2 exceeds 200 μm, the total thickness of the double-sided pressure-sensitive adhesive tape 1 tends to be thick, and a mobile terminal using the double-sided pressure-sensitive adhesive tape 1 tends to be thick.

  Furthermore, the base material 2 of the present embodiment may be subjected to a surface treatment as necessary for the purpose of improving the adhesion between the first pressure-sensitive adhesive layer 3 and the second pressure-sensitive adhesive layer 4. The surface treatment applied to the substrate 2 is not particularly limited, and examples thereof include corona treatment and plasma treatment. Further, an anchor coating agent or the like may be applied to the surface of the substrate 2.

The polyurethane constituting the substrate 2 of the present embodiment is a compound obtained by, for example, condensing polyisocyanate and polyol. For example, polyester urethane resin, polyether urethane resin, polycarbonate urethane resin, epoxy Urethane resin and the like. The polyurethane constituting the substrate 2 is not particularly limited as long as it can be stretched when the double-sided pressure-sensitive adhesive tape 1 is pulled out.
Although it does not specifically limit as polyisocyanate used for the synthesis | combination of a polyurethane, For example, aromatic polyisocyanate, aliphatic polyisocyanate, araliphatic polyisocyanate, alicyclic polyisocyanate etc. can be mentioned. These may be used singly or in combination of two or more.

  Moreover, it does not specifically limit as a polyol used for the synthesis | combination of a polyurethane, For example, a polyol, polyester polyol, polyether polyol, polyester ether polyol, polycarbonate polyol etc. can be mentioned. These may be used singly or in combination of two or more.

The base material 2 of the present embodiment can be manufactured by a melt extrusion molding method in which a resin that is a material of the base material 2 is melted at a high temperature, extruded from a slit-like extrusion port of an extruder, and wound after air cooling. .
Here, the melt extrusion molding method includes 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. Subsequently, the obtained cylindrical film is cut open and wound as a flat film, whereby the base material 2 made of polyurethane is obtained. In addition, when employ | adopting an inflation method, it is possible to manufacture the two base materials 2 simultaneously by opening at two places which oppose when opening a cylindrical film.
In addition, the manufacturing method of the base material 2 is not restricted to the method mentioned above, A well-known method can be employ | adopted without a problem. Moreover, as the base material 2 made of polyurethane, a commercially available product may be used.

<First adhesive layer 3 and second adhesive layer 4>
At least one of the first pressure-sensitive adhesive layer 3 and the second pressure-sensitive adhesive layer 4 of the present embodiment includes a styrene-isoprene-styrene block copolymer, a process oil made of petroleum hydrocarbon, and a tackifier resin. . In the following description, among the first pressure-sensitive adhesive layer 3 and the second pressure-sensitive adhesive layer 4, a pressure-sensitive adhesive layer containing a styrene-isoprene-styrene block copolymer, process oil made of petroleum hydrocarbon, and a tackifier resin is used. May be simply referred to as an “adhesive layer”.

  The thickness of the first pressure-sensitive adhesive layer 3 and the second pressure-sensitive adhesive layer 4 in the present embodiment is 100 μm in total thickness of the base material 2, the first pressure-sensitive adhesive layer 3, and the second pressure-sensitive adhesive layer 4. It is preferable to set the thickness of the base material 2 in consideration of the range of 250 μm or less.

(Styrene-isoprene-styrene block copolymer)
The styrene-isoprene-styrene block copolymer contained in at least one of the first pressure-sensitive adhesive layer 3 and the second pressure-sensitive adhesive layer 4 of the present embodiment is composed of a polystyrene block and a polyisoprene block, and styrene-isoprene. A block copolymer and a styrene-isoprene-styrene triblock copolymer are included.

In the styrene-isoprene-styrene block copolymer of the present embodiment, the styrene-isoprene block amount (SI diblock amount) is preferably 12% by weight or more and 25% by weight or less.
When the amount of SI diblock in the styrene-isoprene-styrene block copolymer is less than 12% by weight, the pressure-sensitive adhesive layer tends to become hard. In this case, the impact resistance of the double-sided adhesive tape 1 may be reduced. Specifically, for example, when an impact is applied to a portable terminal or the like in which the battery is fixed to the casing using the double-sided adhesive tape 1, the battery is detached from the casing or the battery or the portable terminal main body is damaged. There is a risk.

  On the other hand, when the amount of SI diblock in the styrene-isoprene-styrene block copolymer exceeds 25% by weight, the pressure-sensitive adhesive layer tends to be soft and the cohesive force tends to be low. In this case, when the double-sided pressure-sensitive adhesive tape 1 is pulled out from between the adherends, the slipping property between the pressure-sensitive adhesive layer containing the styrene-isoprene-styrene block copolymer and the adherend is lowered, and the double-sided pressure-sensitive adhesive tape 1 is pulled out. Can be difficult. Moreover, the adhesive which comprises the said adhesive layer may remain in the to-be-adhered body after pulling out the double-sided adhesive tape 1. FIG.

Moreover, it is preferable that the amount of styrene in the styrene-isoprene-styrene block copolymer contained in at least one of the first pressure-sensitive adhesive layer 3 and the second pressure-sensitive adhesive layer 4 is in the range of 14 wt% to 25 wt%. .
When the amount of styrene in the styrene-isoprene-styrene block copolymer is less than 14% by weight, the pressure-sensitive adhesive layer tends to be excessively soft and the cohesive force tends to be low. In this case, when the double-sided pressure-sensitive adhesive tape 1 is pulled out from between the adherends, the slipping property between the pressure-sensitive adhesive layer containing the styrene-isoprene-styrene block copolymer and the adherend is lowered, and the double-sided pressure-sensitive adhesive tape 1 is pulled out. Can be difficult. Moreover, the adhesive which comprises the said adhesive layer may remain in the to-be-adhered body after pulling out the double-sided adhesive tape 1. FIG.

  On the other hand, when the amount of styrene in the styrene-isoprene-styrene block copolymer exceeds 25% by weight, the pressure-sensitive adhesive layer tends to be excessively hard. In this case, the impact resistance of the double-sided adhesive tape 1 may be reduced. Specifically, for example, when an impact is applied to a portable terminal or the like in which the battery is fixed to the casing using the double-sided adhesive tape 1, the battery is detached from the casing or the battery or the portable terminal main body is damaged. There is a risk.

  Here, the molecular structure of the styrene-isoprene-styrene block copolymer includes a linear type having no branch, a radial type having a branch, and a hybrid type in which these are mixed. It is preferable that the styrene-isoprene-styrene block copolymer contained in at least one of the first pressure-sensitive adhesive layer 3 and the second pressure-sensitive adhesive layer 4 of the present embodiment has a linear molecular structure.

  In the present embodiment, by using a styrene-isoprene-styrene block copolymer having a linear molecular structure, a styrene-isoprene-styrene block copolymer having a radial or hybrid molecular structure is used. In comparison, the slipping property between the adhesive layer and the adherend when the double-sided adhesive tape 1 is pulled out from between the adherend and the adherend can be improved.

The reason for this is not clear, but is estimated as follows. That is, when the double-sided pressure-sensitive adhesive tape 1 is stretched by using a styrene-isoprene-styrene block copolymer having a linear molecular structure, molecules of the styrene-isoprene-styrene block copolymer that are randomly arranged are aligned. Becomes a straight line. And it is estimated that the styrene domain formed by gathering the styrene blocks at the molecular terminals tends to be unevenly distributed on the surface of the pressure-sensitive adhesive layer, and the surface of the pressure-sensitive adhesive layer becomes hard.
On the other hand, when a styrene-isoprene-styrene block copolymer having a radial type molecular structure is used, since the molecule has a branched portion, the styrene-isoprene-styrene block copolymer having a linear type molecular structure is used. Compared with coalescence, when the double-sided pressure-sensitive adhesive tape 1 is stretched, it is less likely to be linear. For this reason, it is estimated that the styrene domain is less likely to be unevenly distributed on the surface of the pressure-sensitive adhesive layer, and the surface of the pressure-sensitive adhesive layer is somewhat difficult to harden.
As a result, by using a styrene-isoprene-styrene block copolymer having a linear molecular structure, compared to the case of using a styrene-isoprene-styrene block copolymer having a radial or hybrid molecular structure. The pressure-sensitive adhesive layer becomes slippery with the adherend. As a result, the double-sided pressure-sensitive adhesive tape 1 can be easily pulled out from between the adherends.

  Furthermore, the weight average molecular weight (Mw) of the styrene-isoprene-styrene block copolymer contained in at least one of the first pressure-sensitive adhesive layer 3 and the second pressure-sensitive adhesive layer 4 of the present embodiment is particularly limited. However, it is preferably in the range of 150,000 to 250,000, for example. When the weight average molecular weight (Mw) of the styrene-isoprene-styrene block copolymer is excessively small, the cohesive force of the pressure-sensitive adhesive layer is lowered and the adhesive force may be insufficient. On the other hand, when the weight average molecular weight (Mw) of the styrene-isoprene-styrene block copolymer is excessively large, the pressure-sensitive adhesive layer tends to be hard, and the effect of absorbing the impact by the double-sided pressure-sensitive adhesive tape 1 may be insufficient. .

  The pressure-sensitive adhesive layer containing a styrene-isoprene-styrene block copolymer contains other synthetic rubbers, natural rubbers, etc., as long as the properties are not impaired in addition to the styrene-isoprene-styrene block copolymer. May be. Moreover, the said adhesive layer may contain additives, such as anti-aging agent, a heat stabilizer, and a coloring agent, as needed.

(Process oil consisting of petroleum hydrocarbons)
Of the first pressure-sensitive adhesive layer 3 and the second pressure-sensitive adhesive layer 4 of the present embodiment, the pressure-sensitive adhesive layer containing a styrene-isoprene-styrene block copolymer contains process oil made of petroleum hydrocarbon.
The process oil composed of petroleum hydrocarbon blended with the styrene-isoprene-styrene block copolymer makes it easy to process the styrene-isoprene-styrene block copolymer or tackles with the styrene-isoprene-styrene block copolymer. And imparts plasticity, and acts as a softener.

Process oils composed of petroleum hydrocarbons are generally called rubber compounding oils, and include extender oil (extension oil) and process oil (processing oil).
In the process oil composed of petroleum hydrocarbons, the molecules enter between the styrene-isoprene-styrene block copolymers, and improve the lubricity. Thereby, the fluidity between each molecule | numerator of a styrene-isoprene-styrene block copolymer increases, and the internal friction between molecules reduces. As a result, in each step when producing the pressure-sensitive adhesive layer containing the styrene-isoprene-styrene block copolymer, heat generation due to friction between molecules is reduced and workability is improved. Furthermore, the adhesive properties at low temperature of the pressure-sensitive adhesive layer, impact absorbability and the like are improved.

  Moreover, when the double-sided adhesive tape 1 is stretched by increasing the fluidity between the molecules of the styrene-isoprene-styrene block copolymer and reducing the internal friction between the molecules, it is contained in the adhesive layer. The resulting styrene-isoprene-styrene block copolymer tends to be smoothly linear. Thereby, it is presumed that styrene domains formed by collecting styrene blocks at the molecular terminals are unevenly distributed on the surface of the pressure-sensitive adhesive layer, and the surface of the pressure-sensitive adhesive layer is easily hardened. As a result, when the double-sided pressure-sensitive adhesive tape 1 is pulled out from the adherend, the slipping property between the stretched pressure-sensitive adhesive layer and the adherend can be improved, and the pull-out property of the double-sided pressure-sensitive adhesive tape 1 is improved.

Process oils composed of petroleum hydrocarbons are generally a mixture of paraffinic hydrocarbons, naphthenic hydrocarbons, and aromatic hydrocarbons. Depending on the mixing ratio, paraffinic process oils, naphthenic process oils, aromatic carbonizations are used. Divided into hydrogen-based process oils. These process oils can be used alone or in combination.
Among these process oils, it is preferable to use a process oil having a high specific gravity and a high boiling point from the viewpoint of good affinity with the styrene-isoprene-styrene block copolymer.

  Paraffinic process oil and naphthenic process oil are, for example, distillates obtained by atmospheric distillation of paraffinic crude oil, intermediate crude oil, or naphthenic crude oil, or by vacuum distillation of residual oil from atmospheric distillation. It is obtained by refining the oil by known methods. Further, deep dewaxed oil obtained by further deep dewaxing treatment after purification, hydrotreated oil obtained by hydrotreating, or the like may be used. The purification method is not particularly limited, and a known method can be adopted.

Moreover, a commercial item may be used for the process oil consisting of petroleum hydrocarbons.
Specific examples of naphthenic process oil include Diana Fresia N28 (trade name), Diana Fresia U46 (trade name), Diana Process Oil NR (trade name) manufactured by Idemitsu Kosan Co., Ltd., Shelf Rex 371N manufactured by Shell Chemical Co., Ltd. (Brand name) etc. are mentioned.
Specific examples of paraffinic process oils include NA Solvent (trade name) manufactured by Nippon Oil & Fats Co., Ltd., PW-380 (trade name) manufactured by Idemitsu Kosan Co., Ltd., Diana Fresia S32 (trade name), PS-32 (Trade name), IP-solvent 2835 (trade name), Diana Process Oil PW-90 (trade name), Neothiozol (trade name) manufactured by Sanko Chemical Co., Ltd., and the like.
Furthermore, as an aromatic hydrocarbon type process oil, specifically, Diana process oil AC-460 (trade name) manufactured by Idemitsu Kosan Co., Ltd. is exemplified.

  The content of the process oil composed of the petroleum hydrocarbon is preferably in the range of 3 parts by weight to 20 parts by weight with respect to 100 parts by weight of the styrene-isoprene-styrene block copolymer. When the content of the process oil made of petroleum hydrocarbon is less than 3 parts by weight, the impact resistance of the double-sided pressure-sensitive adhesive tape 1 may be insufficient. On the other hand, when the content of the process oil composed of petroleum hydrocarbon exceeds 20 parts by weight, the pullability of the double-sided pressure-sensitive adhesive tape 1 may be insufficient.

(Tackifying resin)
Of the first pressure-sensitive adhesive layer 3 and the second pressure-sensitive adhesive layer 4 of the present embodiment, the pressure-sensitive adhesive layer containing a styrene-isoprene-styrene block copolymer is an aliphatic hydrocarbon resin, a fat as a tackifying resin. At least one resin selected from aromatic aromatic hydrocarbon resins and hydrogenated hydrocarbon resins. These may be used alone or in combination.
The pressure-sensitive adhesive layer containing the styrene-isoprene-styrene block copolymer contains these tackifying resins, so that the adhesion to the adherend is improved compared to the case where these tackifying resins are not included. To do.

The aliphatic hydrocarbon resin used as the tackifier resin of the present embodiment is not particularly limited. For example, QintonR100 (product name), QintonM100 (product name), QintonA100 (manufactured by Zeon Corporation) Trade name), T-REZ RB100 (trade name), T-REZ RC100 (trade name) manufactured by TonenGeneral Sekiyu KK can be used.
In addition, the aliphatic aromatic hydrocarbon resin used as the tackifier resin of the present embodiment is not particularly limited. For example, Qinton D100 (trade name), Qinton N180 (trade name) manufactured by Nippon Zeon Co., Ltd. ), T-REZ RD104 (trade name) manufactured by TonenGeneral Sekiyu KK can be used.
Furthermore, the hydrogenated hydrocarbon resin used as the tackifying resin of the present embodiment is not particularly limited. For example, Alcon P100 (trade name) manufactured by Arakawa Chemical Industries, Ltd., manufactured by TonenGeneral Sekiyu K.K. T-REZ HA103 (trade name) can be used.

The tackifying resin content is preferably in the range of 80 to 100 parts by weight with respect to 100 parts by weight of the styrene-isoprene-styrene block copolymer.
When the content of the tackifier resin is less than 80 parts by weight, the pressure-sensitive adhesive layer tends to be hard because the styrene-isoprene-styrene block copolymer is excessive in the pressure-sensitive adhesive layer. In this case, there is a possibility that the double-sided pressure-sensitive adhesive tape 1 is difficult to be stretched or the impact resistance of the double-sided pressure-sensitive adhesive tape 1 is insufficient.
When the content of the tackifying resin exceeds 100 parts by weight, the content of the styrene-isoprene-styrene block copolymer in the pressure-sensitive adhesive layer is reduced, so that the drawability and impact resistance of the double-sided pressure-sensitive adhesive tape 1 become insufficient. There is a fear.

<Release liner 5, 6>
The release liners 5 and 6 are not particularly limited. For example, the release liner 5 and the second pressure-sensitive adhesive layer 4 can be releasable from a film such as paper, polyethylene, polypropylene, and polyethylene terephthalate. What gave the exfoliation processing for raising it can be used.
The thicknesses of the release liners 5 and 6 are not particularly limited, but are usually in the range of 25 μm to 125 μm.

[Production method of double-sided adhesive tape 1]
Then, the manufacturing method of the double-sided adhesive tape 1 of this Embodiment is demonstrated. In addition, the following description is an example and the manufacturing method of the double-sided adhesive tape 1 is not limited to the following.
In order to produce the double-sided pressure-sensitive adhesive tape 1, for example, the pressure-sensitive adhesive is applied and dried on the release liner 5 to form the first pressure-sensitive adhesive layer 3. Subsequently, the base material 2 made of polyurethane is laminated on the formed first pressure-sensitive adhesive layer 3 to obtain a laminate in which the release liner 5, the first pressure-sensitive adhesive layer 3 and the release liner 5 are laminated.
Subsequently, an adhesive is applied and dried on the release liner 6 to form the second adhesive layer 4. Subsequently, the second pressure-sensitive adhesive layer 4 formed on the release liner 6 is pasted on the surface of the laminate 2 on the side opposite to the surface on which the first pressure-sensitive adhesive layer 3 is laminated. Match. Then, the double-sided adhesive tape 1 which has the laminated structure shown in FIG. 1 is obtained by heating and curing as needed.

[How to use double-sided adhesive tape 1]
Then, the usage method of the double-sided adhesive tape 1 of this Embodiment is demonstrated. FIG. 2 is a diagram illustrating an example of a state in which the double-sided pressure-sensitive adhesive tape 1 to which this exemplary embodiment is applied is used. Moreover, Fig.3 (a)-(c) is the figure which showed the state which pulls out the double-sided adhesive tape 1 to which this Embodiment is applied. 3A to 3C correspond to the view of FIG. 2 viewed from the III direction.

As described above, the double-sided pressure-sensitive adhesive tape 1 of the present embodiment is used for fixing the battery 12 or the like to the housing 11 of the mobile terminal 10 such as a smartphone or a mobile phone.
Note that the casing 11 of the mobile terminal 10 is formed of a metal such as aluminum or a resin material, for example. Moreover, the battery 12 of the portable terminal 10 is usually laminated on the surface with a resin such as nylon, polypropylene, or polyethylene.

  When the battery 12 is fixed to the casing 11 of the mobile terminal 10 with the double-sided adhesive tape 1, first, the release liner 6 (see FIG. 1) of the double-sided adhesive tape 1 is peeled off, and the second adhesive layer 4 is removed. Affixed to the housing 11. Next, the release liner 5 (see FIG. 1) of the double-sided pressure-sensitive adhesive tape 1 is peeled to expose the first pressure-sensitive adhesive layer 3, and then the battery 12 is loaded on the first pressure-sensitive adhesive layer 3, thereby The agent layer 3 and the battery 12 are attached. Thereby, the battery 12 is fixed to the housing 11 of the mobile terminal 10 by the double-sided adhesive tape 1.

  In the present embodiment, as described above, the first pressure-sensitive adhesive layer 3 to which the battery 12 is attached is composed of a rubber-based pressure-sensitive adhesive containing a styrene-isoprene-styrene block copolymer. Thereby, compared with the case where the 1st adhesive layer 3 is comprised with another adhesive, for example, the adhesive force with respect to the battery 12 laminated | stacked with resin becomes favorable, and when an impact is added, from the housing | casing 11 The battery 12 is prevented from peeling off.

  Here, as described above, when the double-sided pressure-sensitive adhesive tape 1 of the present embodiment is used for the purpose of fixing the battery 12 to the casing 11 of the mobile terminal 10, for example, in order to remove the battery 12 from the casing 11. In some cases, the double-sided adhesive tape 1 may be pulled out from between the housing 11 and the battery 12. In the present embodiment, in order to facilitate the drawing operation of the double-sided pressure-sensitive adhesive tape 1, the double-sided pressure-sensitive adhesive tape 1 is placed so that the end 1a of the double-sided pressure-sensitive adhesive tape 1 protrudes outside the battery 12, as shown in FIG. It is preferable to paste.

Next, an operation when the double-sided adhesive tape 1 is pulled out from between the housing 11 of the mobile terminal 10 and the battery 12 will be described.
When the double-sided pressure-sensitive adhesive tape 1 is pulled out from between the adherends (between the housing 11 and the battery 12), the end 1a of the double-sided pressure-sensitive adhesive tape 1 protruding outside the battery 12 is gripped, and FIG. Pull in the direction of arrow A in 3 (a). In other words, the end portion 1 a of the double-sided pressure-sensitive adhesive tape 1 is gripped and pulled in an obliquely upward direction inclined toward the battery 12 with respect to the interface between the first pressure-sensitive adhesive layer 3 and the battery 12.

  As described above, the base material 2 of the present embodiment is made of stretchable polyurethane. Thereby, as shown in FIG.3 (b), when the edge part 1a of the double-sided adhesive tape 1 is pulled, the double-sided adhesive tape 1 is extended in the tension | pulling direction. More specifically, the base material 2 of the double-sided pressure-sensitive adhesive tape 1 is stretched in the pulling direction, and accordingly, the first pressure-sensitive adhesive layer 3 and the second pressure-sensitive adhesive layer 4 laminated on the base material 2 are pulled in the pulling direction. Stretched.

  And the double-sided pressure-sensitive adhesive tape 1 is stretched in the pulling direction, so that the double-sided pressure-sensitive adhesive tape 1 contracts in the width direction as shown by the broken line arrow B in FIGS. As indicated by the broken line arrow C, the film shrinks in the thickness direction. In other words, when the double-sided pressure-sensitive adhesive tape 1 is stretched in the pulling direction, the force applied when the double-sided pressure-sensitive adhesive tape 1 is stretched in the pulling direction is applied to the first pressure-sensitive adhesive layer 3 in the width direction and It is distributed in the thickness direction. At this time, the base material 2 undergoes deformation unique to polyurethane in the width direction and the thickness direction, so that the force applied when the double-sided pressure-sensitive adhesive tape 1 is stretched in the pulling direction is gently transmitted to the first pressure-sensitive adhesive layer 3. . As a result, the first pressure-sensitive adhesive layer 3 is gradually peeled off from the surface of the battery 12 without being left behind while gradually narrowing in the width direction together with the base material 2. Similarly, as for the second adhesive layer 4 and the housing 11 of the double-sided adhesive tape 1, the second adhesive layer 4 is peeled off from the surface of the housing 11 while the contact area gradually decreases.

  In addition, the double-sided pressure-sensitive adhesive tape 1 is stretched in the pulling direction, so that in the interface between the first pressure-sensitive adhesive layer 3 and the battery 12, the downstream side in the pulling direction indicated by X in FIG. 2 and FIG. The first pressure-sensitive adhesive layer 3 peeled by the movement moves while sliding on the surface of the battery 12 in the pulling direction. At this time, when the slip property between the first pressure-sensitive adhesive layer 3 peeled by stretching and the surface of the battery 12 is low, the double-sided pressure-sensitive adhesive tape 1 is cut before being pulled out from between the battery 12 and the housing 11. There is a risk of it. On the other hand, in the double-sided pressure-sensitive adhesive tape 1 of the present embodiment, the first pressure-sensitive adhesive layer 3 has the above-described configuration, so that the slip property between the first pressure-sensitive adhesive layer 3 peeled off by stretching and the surface of the battery 12 can be obtained. Is good. Thereby, it is suppressed that the double-sided adhesive tape 1 is cut before being pulled out from between the battery 12 and the housing 11.

As described above, as indicated by the broken line arrow C in FIG. 3C, the double-sided pressure-sensitive adhesive tape 1 is gradually peeled off from between the housing 11 of the mobile terminal 10 and the battery 12 and pulled out.
Thus, in the present embodiment, the battery 12 can be removed from the housing 11 by a simple operation of pulling the double-sided adhesive tape 1 from between the housing 11 and the battery 12 of the mobile terminal 10.

  In the present embodiment, both the first pressure-sensitive adhesive layer 3 and the second pressure-sensitive adhesive layer 4 are made of styrene-isoprene-styrene block copolymer, process oil made of petroleum hydrocarbon, and tackifying resin. The example comprised by the adhesive containing this was demonstrated. However, in the double-sided pressure-sensitive adhesive tape 1, if at least one of the first pressure-sensitive adhesive layer 3 and the second pressure-sensitive adhesive layer 4 is composed of the above-described pressure-sensitive adhesive, the other may be composed of another pressure-sensitive adhesive. Good. For example, when using the double-sided pressure-sensitive adhesive tape 1 in which the first pressure-sensitive adhesive layer 3 is composed of the above-described pressure-sensitive adhesive and the second pressure-sensitive adhesive layer 4 is composed of another pressure-sensitive adhesive for use in attaching a battery to the casing of the mobile terminal, It is preferable to use the first pressure-sensitive adhesive layer 3 attached to the battery side and the second pressure-sensitive adhesive layer 4 attached to the housing side. Thereby, like the example shown to Fig.3 (a)-(c), when pulling out the double-sided adhesive tape 1, the 1st adhesive layer 3 moves, sliding on the surface of a battery.

  The other pressure-sensitive adhesive that can be used for the double-sided pressure-sensitive adhesive tape 1 is not particularly limited as long as it has an adhesive force to the adherend and can be peeled off from the double-sided pressure-sensitive adhesive tape 1, for example, Known acrylic adhesives, silicone adhesives, other rubber adhesives, and the like can be used.

  Next, the present invention will be described more specifically based on examples. However, the present invention is not limited to the following examples.

1. Preparation of double-sided adhesive tape 1 <Example 1>
To 100 parts by weight of styrene-isoprene-styrene block copolymer (manufactured by Nippon Zeon Co., Ltd., Qintac 3280, styrene amount 25% by weight, SI diblock amount 17% by weight, linear type), tackifying resin (Nippon Zeon Corporation) , QintonR100, aliphatic hydrocarbon resin 100 parts by weight, anti-aging agent (BASF Japan KK, Irganox 1010) 1.0 part by weight, process oil consisting of petroleum hydrocarbons (Idemitsu Kosan KK, Diana Process) (Oil NS-90S) was mixed with 10 parts by weight, diluted with toluene to a non-volatile content of about 50%, and stirred at room temperature for 48 hours or longer to obtain an adhesive solution.
Subsequently, the obtained pressure-sensitive adhesive solution was applied to a 100 μm-thick release liner (manufactured by Sumika Kogyo Co., Ltd., SLB-50KWD (# 2302)) with a doctor coater, and dried at about 110 ° C. for 3 minutes. A pressure-sensitive adhesive layer having a thickness of 30 μm corresponding to the first pressure-sensitive adhesive layer 3 to be bonded to the battery side was formed.

On the pressure-sensitive adhesive layer formed on the release liner, a base material 2 made of a polyurethane film having a thickness of 40 μm (manufactured by Okura Kogyo Co., Ltd., NES-85L) was bonded to prepare a single-sided pressure-sensitive adhesive tape.
Subsequently, a pressure-sensitive adhesive layer having a thickness of 30 μm corresponding to the second pressure-sensitive adhesive layer 4 bonded to the housing side was formed on the release liner in the same manner as described above. And this adhesive layer is bonded together to the base material 2 side of a single-sided adhesive tape, and the elongation rate by which the adhesive layer (the 1st adhesive layer 3 and the 2nd adhesive layer 4) was laminated | stacked on both surfaces of the base material 2 740% (no yield point) double-sided pressure-sensitive adhesive tape 1 was obtained. In this example, the two pressure-sensitive adhesive layers (the first pressure-sensitive adhesive layer 3 and the second pressure-sensitive adhesive layer 4) formed on both surfaces of the substrate 2 have the same configuration.

<Example 2>
Except that styrene-isoprene-styrene block copolymer (manufactured by Nippon Zeon Co., Ltd., Qintac 3620, styrene amount 14% by weight, SI diblock amount 12% by weight, hybrid type) was used for the production of the adhesive solution. In the same manner as in Example 1, a double-sided pressure-sensitive adhesive tape 1 having an elongation of 760% (no yield point) was obtained.

<Example 3>
Except for using a styrene-isoprene-styrene block copolymer (manufactured by Nippon Zeon Co., Ltd., Qintac 3421, styrene amount 14% by weight, SI diblock amount 26% by weight, linear type) for the production of the adhesive solution, In the same manner as in Example 1, a double-sided pressure-sensitive adhesive tape 1 having an elongation of 780% (no yield point) was obtained.

<Example 4>
In the same manner as in Example 1, except that 100 parts by weight of a tackifier resin (manufactured by Zeon Corporation, Qinton D100, aliphatic aromatic hydrocarbon resin) was used for the production of the adhesive solution, the elongation 730 % (No yield point) double-sided pressure-sensitive adhesive tape 1 was obtained.

<Example 5>
Except for using 100 parts by weight of a tackifier resin (Arakawa Chemical Industries, Ltd., Alcon P100, hydrogenated hydrocarbon resin) for the production of the adhesive solution, the elongation percentage was 730% ( A double-sided pressure-sensitive adhesive tape 1 having no yield point was obtained.

<Example 6>
Except for using a styrene-isoprene-styrene block copolymer (manufactured by Nippon Zeon Co., Ltd., Qintac 3450, styrene amount 19% by weight, SI diblock amount 30% by weight, radial type) for the production of the adhesive solution, In the same manner as in Example 1, a double-sided pressure-sensitive adhesive tape 1 having an elongation of 740% (no yield point) was obtained.

<Example 7>
After mixing 1.5 parts by weight of an isocyanate-based crosslinking agent (Saiden Chemical Co., Ltd., Cybinol Curing Agent AL) with 100 parts by weight of an acrylic adhesive (Saiden Chemical Co., Ltd., Cybinol AT-D54N), at room temperature The mixture was stirred for 10 minutes or more to obtain an adhesive solution. The non-volatile content of this adhesive solution is about 38%.
Using this pressure-sensitive adhesive solution, an elongation rate of 740% (no yield point) was obtained in the same manner as in Example 1 except that a pressure-sensitive adhesive layer corresponding to the second pressure-sensitive adhesive layer 4 to be bonded to the housing side was formed. ) Was obtained. In this example, the two pressure-sensitive adhesive layers (the first pressure-sensitive adhesive layer 3 and the second pressure-sensitive adhesive layer 4) formed on both surfaces of the substrate 2 have different configurations.

<Comparative Example 1>
Except that a 38 μm thick polyethylene terephthalate (PET) film (manufactured by Nanya Plastic Co., Ltd., BP21) was used as the substrate 2, the elongation was 135% (no yield point). A double-sided pressure-sensitive adhesive tape 1 was obtained.

<Comparative example 2>
A double-sided pressure-sensitive adhesive tape 1 having an elongation of 700% (no yield point) was obtained in the same manner as in Example 1 except that the styrene-isoprene-styrene block copolymer was not used in the production of the pressure-sensitive adhesive solution. .

<Comparative Example 3>
A double-sided pressure-sensitive adhesive tape 1 having an elongation of 740% (no yield point) was obtained in the same manner as in Example 1 except that no process oil comprising petroleum hydrocarbon was used in the production of the pressure-sensitive adhesive solution.

<Comparative example 4>
A double-sided pressure-sensitive adhesive tape 1 having an elongation of 750% (no yield point) was obtained in the same manner as in Example 1 except that no tackifying resin was used in the production of the pressure-sensitive adhesive solution.

<Comparative Example 5>
Example 1 except that both the first pressure-sensitive adhesive layer 3 to be bonded to the battery side and the second pressure-sensitive adhesive layer 4 to be bonded to the housing side were prepared using the acrylic pressure-sensitive adhesive used in Example 7. In the same manner as in Example 1, a double-sided pressure-sensitive adhesive tape 1 having an elongation of 750% (no yield point) was obtained.

2. Evaluation Method Subsequently, an evaluation method of the double-sided pressure-sensitive adhesive tape 1 will be described.
(1) Drop test The double-sided pressure-sensitive adhesive tape 1 obtained in Examples 1 to 7 and Comparative Examples 1 to 5 was cut into a rectangle having a width of 10 mm and a length of 40 mm. Subsequently, a plate made of polypropylene assuming the battery surface (polypropylene plate, 30 mm × 50 mm, thickness 3 mm, 25 g) and a metal casing were bonded using two cut double-sided adhesive tapes 1. . Here, the two double-sided pressure-sensitive adhesive tapes 1 were bonded together in the width direction between the polypropylene plate and the casing. Moreover, it bonded together so that the 1st adhesive layer 3 might oppose a polypropylene board among the double-sided adhesive tapes 1, and the 2nd adhesive layer 4 might oppose a housing | casing.
Then, after pressing the polypropylene board and housing | casing bonded with the double-sided adhesive tape 1 at 0.3 MPa for 10 second, it was left to stand for 20 minutes and was set as the test piece.

This test piece was assembled in a rectangular parallelepiped steel can (180 mm × 70 mm × 15 mm), and the total weight was adjusted to 220 g. And the steel can in which the test piece was incorporated was dropped from the height of 1 m to the concrete in 10 directions of the 6th face and 4 corners of the steel can. After performing 2 sets of this, the test piece was taken out from the steel can, and it was evaluated whether the polypropylene plate and the housing were detached.
The evaluation criteria are as follows.
A: The polypropylene plate and the casing are not peeled off.
C: The polypropylene plate and the casing are peeled off.

(2) Pull-out test The double-sided pressure-sensitive adhesive tape 1 obtained in Examples 1 to 7 and Comparative Examples 1 to 5 was cut into a rectangle having a width of 10 mm and a length of 50 mm. Subsequently, a plate made of polypropylene assuming the battery surface using the cut double-sided adhesive tape 1 (polypropylene plate, 50 mm × 125 mm, thickness 3 mm, 17 g) and a plate made of stainless steel assuming the casing (stainless steel plate, 50 mm × 125 mm, thickness 1 mm, 70 g). At this time, the double-sided pressure-sensitive adhesive tape 1 was bonded so that the first pressure-sensitive adhesive layer 3 was opposed to the polypropylene plate and the second pressure-sensitive adhesive layer 4 was opposed to the stainless steel plate. Further, the lengthwise end portion 10 mm of the double-sided pressure-sensitive adhesive tape 1 protruded outward from between the polypropylene plate and the stainless steel plate, and was used as a grip for pulling out the double-sided pressure-sensitive adhesive tape 1.
Subsequently, the test piece was placed so that the polypropylene plate side was on the upper side, and the end (grip margin) of the double-sided pressure-sensitive adhesive tape 1 was gripped to make an angle of 0 ° (horizontal direction) and an angle of 30 ° (with respect to the polypropylene plate). Whether or not the entire double-sided pressure-sensitive adhesive tape 1 was pulled out without being cut halfway was evaluated with the number of trials N = 10. The double-sided pressure-sensitive adhesive tape 1 was pulled out at 23 ° C.

The evaluation criteria are as follows.
A: The double-sided pressure-sensitive adhesive tape 1 that can be pulled out is 80% or more B: The double-sided pressure-sensitive adhesive tape 1 that can be pulled out is 50% or more and less than 80% C: The double-sided pressure-sensitive adhesive tape 1 that can be pulled out is less than 50%

(3) Measurement of friction coefficient The double-sided pressure-sensitive adhesive tape 1 having a width of 20 mm obtained in Examples 1 to 7 and Comparative Examples 1 to 5 is placed on the pedestal side of a surface property tester (HEIDEN Type 140R manufactured by Shinto Kagaku Co., Ltd.). A marked interval was set to 10 mm, and a test piece was prepared by pasting the adhesive layer so that one of the adhesive layers was exposed on the surface in a state of being stretched 5 times.
Subsequently, the tip flat portion (assuming the battery surface) of the knife-like jig plate whose surface is coated with nylon is applied to the adhesive layer of the test piece (first adhesive layer 3) with a load of 200 gf of vertical drag. The dynamic friction coefficient when rubbed at a speed of 300 mm / min was measured.
(F = μN, F: friction force, μ: friction coefficient, N: vertical drag)

3. Evaluation results The evaluation results of Examples 1 to 7 are shown in Table 1, and the evaluation results of the double-sided pressure-sensitive adhesive tapes 1 of Comparative Examples 1 to 5 are shown in Table 2.
In addition, since the double-sided adhesive tape 1 of the comparative example 1 was able to stretch only to 135% and fractured, the measurement of the friction coefficient could not be carried out.
Moreover, since the double-sided adhesive tape 1 of the comparative example 2 did not have the cohesive force of an adhesive and did not function as an adhesive tape, the drop test, the pullability test, and the measurement of the friction coefficient could not be carried out.
Furthermore, the double-sided pressure-sensitive adhesive tape 1 of Comparative Example 4 had no tackiness of the pressure-sensitive adhesive, and hardly functioned as a pressure-sensitive adhesive tape. Therefore, the drop test and the pullability test could not be performed.

  As shown in Table 1, polyurethane is used as the base material 2, and at least one of the pressure-sensitive adhesive layers (first pressure-sensitive adhesive layer 3 and second pressure-sensitive adhesive layer 4) laminated on both surfaces of the base material 2 is styrene. -Adhesion containing at least one selected from isoprene-styrene block copolymer, process oil composed of petroleum hydrocarbon, aliphatic hydrocarbon resin, aliphatic aromatic hydrocarbon resin, hydrogenated hydrocarbon resin In the double-sided pressure-sensitive adhesive tapes 1 of Examples 1 to 7 including the imparting resin, it was confirmed that the casing and the polypropylene plate were not detached in the drop test, and good results were obtained in the pull-out test. It was.

  On the other hand, in Comparative Example 1 using PET without using polyurethane as the base material 2, the double-sided pressure-sensitive adhesive tape 1 was not removed even when the end portion (grip margin) of the double-sided pressure-sensitive adhesive tape 1 was gripped and pulled in the pullout test. Since it hardly stretched, the double-sided pressure-sensitive adhesive tape 1 could not be pulled out in all trials N = 10. In Comparative Example 1, the polypropylene plate and the casing were peeled off in the drop test. For this reason, it was confirmed that the double-sided pressure-sensitive adhesive tape 1 of Comparative Example 1 is clearly inferior in pull-out property and impact absorbability as compared with Example 1 in which the pressure-sensitive adhesive layer is the same.

  In Comparative Example 2 in which the styrene-isoprene-styrene block copolymer is not used in the pressure-sensitive adhesive layer and in Comparative Example 4 in which no tackifying resin is used in the pressure-sensitive adhesive layer, a drop test and a pullability test are performed. I could not. Moreover, in the comparative example 3 which does not use the process oil which consists of petroleum hydrocarbons for an adhesive layer, the result in a drop test compared with Example 1 which used the process oil which consists of petroleum hydrocarbons for an adhesive layer. Inferiority was confirmed.

  Furthermore, in Comparative Example 5 in which the acrylic pressure-sensitive adhesive was used for both of the pressure-sensitive adhesive layers (the first pressure-sensitive adhesive layer 3 and the second pressure-sensitive adhesive layer 4) laminated on both surfaces of the base material 2, Examples 1 to Compared to 7, it was confirmed that the results in both the drop test and the pullout test were inferior.

  Further, when Examples 1 to 6 are compared with each other, the molecular structure of Example 3 and the styrene-isoprene-styrene block copolymer in which the amount of SI diblock of the styrene-isoprene-styrene block copolymer is higher than 25% by weight is In the radial type Example 6, it was confirmed that the result in the pullability test was slightly inferior compared with the other examples.

DESCRIPTION OF SYMBOLS 1 ... Double-sided adhesive tape, 2 ... Base material, 3 ... 1st adhesive layer, 4 ... 2nd adhesive layer, 10 ... Portable terminal, 11 ... Housing | casing, 12 ... Battery

Claims (3)

A substrate made of polyurethane;
A pressure-sensitive adhesive layer laminated on each of both surfaces of the base material,
At least one of the pressure-sensitive adhesive layers is
A styrene-isoprene-styrene block copolymer;
Process oils consisting of petroleum hydrocarbons;
A double-sided pressure-sensitive adhesive tape comprising: a tackifying resin containing at least one selected from an aliphatic hydrocarbon resin, an aliphatic aromatic hydrocarbon resin, and a hydrogenated hydrocarbon resin.   The styrene-isoprene-styrene block copolymer has a styrene content ranging from 14% by weight to 25% by weight, and a styrene-isoprene block content ranging from 12% by weight to 25% by weight. The double-sided pressure-sensitive adhesive tape according to claim 1.   The double-sided pressure-sensitive adhesive tape according to claim 1 or 2, wherein the styrene-isoprene-styrene block copolymer has a linear molecular structure.

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