JPWO2018181336A1 - Double-sided adhesive tape - Google Patents

Abstract

An object of the present invention is to provide a double-sided pressure-sensitive adhesive tape having excellent stress relaxation and impact resistance, and also having excellent reworkability on both pressure-sensitive adhesive surfaces. The present invention provides a double-sided pressure-sensitive adhesive tape having a foam substrate and a first pressure-sensitive adhesive layer and a second pressure-sensitive adhesive layer on both surfaces of the foam substrate, respectively. Both surfaces having a first resin layer and a second resin layer having a tensile stress at break of 4 MPa or more between the pressure-sensitive adhesive layers and between the foam base material and the second pressure-sensitive adhesive layer, respectively. It is an adhesive tape.

Description

The present invention relates to a double-sided pressure-sensitive adhesive tape having excellent stress relaxation properties and impact resistance, and having excellent reworkability on both pressure-sensitive adhesive faces.

2. Description of the Related Art Double-sided adhesive tapes are used for assembling in portable electronic devices such as mobile phones and personal digital assistants (Personal Digital Assistants, PDAs) (for example, Patent Documents 1 and 2). Further, a double-sided adhesive tape is also used for fixing a vehicle-mounted electronic device component such as a vehicle-mounted panel to a vehicle body.

JP 2009-242541 A JP 2009-258274 A

High adhesive strength is required for double-sided adhesive tapes used for fixing portable electronic device parts, vehicle-mounted electronic device parts, and the like. Further, in recent years, portable electronic devices, in-vehicle electronic devices, and the like have a tendency to become more complicated in shape with higher functionality, so that a double-sided adhesive tape should be applied to steps, corners, non-planar portions, and the like. There is. In such a case, since the double-sided adhesive tape is fixed in a deformed state, a force for returning to the original shape, that is, a restoring force or a repulsive force acts, and the double-sided adhesive tape may peel off over time. Was. In particular, when fixing a part in a deformed state, the part itself tries to return to the original shape, and the restoring force and repulsive force are applied to the double-sided adhesive tape, and the fixing is insufficient or the double-sided adhesive tape Peeling sometimes occurred. In order to prevent peeling due to such a restoring force or repulsive force, a double-sided adhesive tape is required to have excellent stress relaxation. In addition, the double-sided adhesive tape was sometimes required to have impact resistance.

As a double-sided pressure-sensitive adhesive tape having excellent stress relaxation properties and excellent impact resistance, a double-sided pressure-sensitive adhesive tape using a foam base material is known. However, in the case of a conventional double-sided adhesive tape using a foam base material, the foam base material is broken at the time of peeling when used for a temporary fixing purpose or when it is desired to peel off after lamination for some reason. There is a problem that a residue may remain on the body, resulting in poor reworkability. Particularly in double-sided pressure-sensitive adhesive tapes, reworkability on both pressure-sensitive adhesive surfaces has been required.

An object of the present invention is to provide a double-sided pressure-sensitive adhesive tape having excellent stress relaxation and impact resistance, and having excellent reworkability on both pressure-sensitive adhesive surfaces.

The present invention provides a double-sided pressure-sensitive adhesive tape having a foam base material and a first pressure-sensitive adhesive layer and a second pressure-sensitive adhesive layer on both surfaces of the foam base material, respectively. Both surfaces having a first resin layer and a second resin layer having a tensile stress at break of 4 MPa or more between the pressure-sensitive adhesive layers and between the foam base material and the second pressure-sensitive adhesive layer, respectively. It is an adhesive tape.
Hereinafter, the present invention will be described in detail.

The present inventors have found that a double-sided pressure-sensitive adhesive tape having a foam substrate and a first pressure-sensitive adhesive layer and a second pressure-sensitive adhesive layer on both surfaces of the foam substrate, respectively, comprises a foam substrate and a first pressure-sensitive adhesive. The first resin layer and the second resin layer each having a tensile stress at break were equal to or more than a certain value between the layers and between the foam base material and the second pressure-sensitive adhesive layer. By disposing such a first resin layer and a second resin layer, the present inventors adopt a foam base material capable of exhibiting excellent stress relaxation property and impact resistance, while using a foam base material capable of exhibiting excellent stress relaxation properties. It has been found that excellent reworkability can be exhibited, and the present invention has been completed.

FIG. 1 is a schematic view showing an example of a double-sided pressure-sensitive adhesive tape according to one embodiment of the present invention. A double-sided pressure-sensitive adhesive tape 1 according to one embodiment of the present invention in FIG. 1 has a first pressure-sensitive adhesive layer 31 and a second pressure-sensitive adhesive layer 32 on both surfaces of a foam base material 2. The first resin layer 41 is disposed between the foam base material 2 and the first pressure-sensitive adhesive layer 31, and the second resin layer 41 is disposed between the foam base material 2 and the second pressure-sensitive adhesive layer 32. A layer 42 is disposed.

The double-sided pressure-sensitive adhesive tape according to one embodiment of the present invention has a foam base material and a first pressure-sensitive adhesive layer and a second pressure-sensitive adhesive layer on both surfaces of the foam base material, respectively.
By using the foam base material, the double-sided pressure-sensitive adhesive tape according to one embodiment of the present invention can exhibit excellent stress relaxation and impact resistance. The foam base material may have an open cell structure or a closed cell structure, but preferably has an open cell structure. By using a foam base material having an open cell structure, more excellent stress relaxation and impact resistance can be exhibited. The foam base material may have a single-layer structure or a multilayer structure.

The foam base is not particularly limited, and examples thereof include a polyurethane foam, a polyolefin foam, a rubber-based resin foam, and an acrylic foam. Among them, a polyurethane foam or a polyolefin foam is preferred because it can easily form an open cell structure and can exhibit excellent stress relaxation and impact resistance.

The density of the foam base material is not particularly limited, but a preferred lower limit is 0.03 g / cm ³ and a preferred upper limit is 0.8 g / cm ³ . By setting the density of the foam base material within this range, it is possible to exhibit excellent stress relaxation and impact resistance while maintaining the strength of the double-sided pressure-sensitive adhesive tape. In light of the strength, the stress relaxation property, and the impact resistance of the double-sided pressure-sensitive adhesive tape, a more preferable lower limit of the base material is 0.1 g / cm ³ , a more preferable upper limit is 0.7 g / cm ³ , and a still more preferable lower limit is 0. .15 g / cm ³ , a more preferred upper limit is 0.5 g / cm ³ , a particularly preferred lower limit is 0.2 g / cm ³ , and a particularly preferred upper limit is 0.4 g / cm ³ .
The density can be measured using an electronic hydrometer (for example, “ED120T” manufactured by Mirage Co., Ltd.) in accordance with JIS K6767.

Although the 25% compressive strength of the foam base material is not particularly limited, a preferable lower limit is 1 kPa and a preferable upper limit is 100 kPa. By setting the 25% compressive strength of the foam base material within this range, excellent stress relaxation and impact resistance can be exhibited while maintaining the strength of the double-sided pressure-sensitive adhesive tape. From the viewpoint of further improving the strength, stress relaxation and impact resistance of the double-sided pressure-sensitive adhesive tape, a more preferred lower limit of the 25% compressive strength of the base material is 3 kPa, a more preferred upper limit is 50 kPa, and a still more preferred lower limit is 5 kPa, A preferred upper limit is 40 kPa.
The 25% compressive strength can be determined by measuring according to JIS K 6254.

Although the shear storage modulus of the foam base material is not particularly limited, the frequency in the master curve measured with a dynamic viscoelastic device and synthesized at a reference temperature of 23 ° C. is 1.0 × 10 ^{−4 to} 1.0 × 10 ^−. It is preferable that the maximum value of the shear storage modulus in a ⁵ Hz region is 1.0 × 10 ⁵ Pa or less. The frequency range is a frequency corresponding to the peeling stress at a low speed generated when a restoring force or a repulsive force is applied to the double-sided adhesive tape. If the maximum value of the shear storage modulus in the frequency range is 1.0 × 10 ⁵ Pa or less, the stress when a restoring force or a repulsive force is applied to the double-sided adhesive tape is reduced by the foam base material, Since it is difficult to transmit to the pressure-sensitive adhesive layer, the stress relaxation property and the impact resistance of the double-sided pressure-sensitive adhesive tape can be improved.
The shear storage modulus is in the range of −60 ° C. to 250 ° C. using a dynamic viscoelasticity measuring apparatus (for example, DVA-200 manufactured by IT Keisoku Co., Ltd.) at a temperature rising rate of 5 ° C./min. Can be measured. When measuring the shear storage modulus, an adhesive is applied to both sides of the substrate to measure the displacement of the sample during the measurement. The pressure-sensitive adhesive is not particularly limited, but the pressure-sensitive adhesive applied to both sides of the substrate is adjusted so that the thickness is 15% or less of the thickness of the substrate, and the measurement is performed. By setting the thickness of the pressure-sensitive adhesive to 15% or less of the thickness of the base material, the influence of the pressure-sensitive adhesive can be eliminated as much as possible, and the shear storage modulus of the base material can be measured.

The thickness of the foam base material is not particularly limited, but a preferred lower limit is 0.2 mm and a preferred upper limit is 2.9 mm. By setting the thickness of the foam base material within this range, the double-sided pressure-sensitive adhesive tape according to one embodiment of the present invention can be suitably used for fixing portable electronic device components, vehicle-mounted electronic device components, and the like. From the viewpoint of being more suitably used for fixing the above components and the like, a more preferred lower limit of the thickness of the foam base material is 0.3 mm, and a more preferred upper limit is 2.5 mm.

The first pressure-sensitive adhesive layer and the second pressure-sensitive adhesive layer (hereinafter, also referred to simply as “pressure-sensitive adhesive layer”) may have the same composition or different compositions. The pressure-sensitive adhesive layer is not particularly limited, and examples thereof include an acrylic pressure-sensitive adhesive layer, a rubber-based pressure-sensitive adhesive layer, a urethane pressure-sensitive adhesive layer, and a silicone-based pressure-sensitive adhesive layer. Among them, an acrylic pressure-sensitive adhesive layer containing an acrylic copolymer because it is relatively stable to light, heat, moisture, etc. and can be bonded to various adherends (low adherence selectivity) Is preferred.

The acrylic copolymer constituting the acrylic pressure-sensitive adhesive layer is preferably obtained by copolymerizing a monomer mixture containing butyl acrylate and 2-ethylhexyl acrylate. The preferred lower limit of the content of the butyl acrylate in the entire monomer mixture is 40% by weight, and the preferred upper limit is 80% by weight. By setting the content of the butyl acrylate within this range, both high adhesive strength and tackiness can be achieved. The preferred lower limit of the content of 2-ethylhexyl acrylate in the entire monomer mixture is 10% by weight, and the preferred upper limit is 40% by weight. By setting the content of the 2-ethylhexyl acrylate within this range, high adhesive strength can be exhibited.

The monomer mixture may contain other polymerizable monomers other than butyl acrylate and 2-ethylhexyl acrylate, if necessary. Examples of the other polymerizable monomers that can be copolymerized include, for example, alkyl (meth) acrylates having 1 to 3 carbon atoms of an alkyl group, alkyl (meth) acrylates having 13 to 18 carbon atoms of an alkyl group, Functional monomers and the like.
Examples of the alkyl (meth) acrylate having 1 to 3 carbon atoms in the alkyl group include methyl (meth) acrylate, ethyl (meth) acrylate, n-propyl (meth) acrylate, and (meth) acrylic acid. Isopropyl and the like. Examples of the alkyl (meth) acrylate having 13 to 18 carbon atoms in the alkyl group include tridecyl methacrylate and stearyl (meth) acrylate. Examples of the functional monomer include hydroxyalkyl (meth) acrylate, glycerin dimethacrylate, glycidyl (meth) acrylate, 2-methacryloyloxyethyl isocyanate, (meth) acrylic acid, itaconic acid, maleic anhydride, crotonic acid, Maleic acid, fumaric acid and the like can be mentioned.

In order to obtain the acrylic copolymer by copolymerizing the monomer mixture, a radical reaction may be performed on the monomer mixture in the presence of a polymerization initiator. As a method of causing a radical reaction of the monomer mixture, that is, a polymerization method, a conventionally known method is used, and examples thereof include solution polymerization (boiling point polymerization or constant temperature polymerization), emulsion polymerization, suspension polymerization, bulk polymerization, and the like.

The weight-average molecular weight (Mw) of the acrylic copolymer has a preferred lower limit of 400,000 and a preferred upper limit of 1.5 million. By setting the weight average molecular weight of the acrylic copolymer within this range, high adhesive strength can be exhibited. A more preferred lower limit of the weight average molecular weight is 500,000, and a more preferred upper limit is 1.4 million.
The weight average molecular weight (Mw) is a weight average molecular weight in terms of standard polystyrene measured by GPC (Gel Permeation Chromatography).

A preferable upper limit of the ratio (Mw / Mn) of the weight average molecular weight (Mw) to the number average molecular weight (Mn) of the acrylic copolymer is 10.0. When Mw / Mn exceeds 10.0, low molecular components increase, and the acrylic pressure-sensitive adhesive layer softens at a high temperature, so that the bulk strength may decrease and the adhesive strength may decrease. A more preferred upper limit of Mw / Mn is 3.0.

The pressure-sensitive adhesive layer may contain a tackifier resin.
Examples of the tackifying resin include a rosin ester resin, a hydrogenated rosin resin, a terpene resin, a terpene phenol resin, a cumarone indene resin, an alicyclic saturated hydrocarbon resin, a C5 petroleum resin, and a C9 resin. Petroleum resins, C5-C9 copolymer petroleum resins, and the like. These tackifier resins may be used alone or in combination of two or more.

The content of the tackifier resin is not particularly limited, but a preferable lower limit is 10 parts by weight, and a preferable upper limit is 60 parts by weight based on 100 parts by weight of a resin (for example, an acrylic copolymer) as a main component of the pressure-sensitive adhesive layer. . If the content of the tackifier resin is less than 10 parts by weight, the adhesive strength of the pressure-sensitive adhesive layer may decrease. If the content of the tackifier resin exceeds 60 parts by weight, the pressure-sensitive adhesive layer may be hard and the adhesive strength or tackiness may be reduced.

In the pressure-sensitive adhesive layer, a cross-linking structure is formed between main chains of a resin (for example, the acrylic copolymer, the tackifying resin, or the like) constituting the pressure-sensitive adhesive layer by adding a cross-linking agent. Is preferred. The crosslinking agent is not particularly limited, and examples thereof include an isocyanate-based crosslinking agent, an aziridine-based crosslinking agent, an epoxy-based crosslinking agent, and a metal chelate-type crosslinking agent. Of these, isocyanate-based crosslinking agents are preferred. By adding an isocyanate-based cross-linking agent to the pressure-sensitive adhesive layer, the isocyanate group of the isocyanate-based cross-linking agent and the alcohol in the resin constituting the pressure-sensitive adhesive layer (for example, the acrylic copolymer, the tackifying resin, etc.) The cross-linking of the pressure-sensitive adhesive layer is loosened by the reaction with the hydroxyl group. Therefore, the pressure-sensitive adhesive layer can disperse the intermittent peeling stress, and the adhesive strength of the double-sided pressure-sensitive adhesive tape is further improved.
The amount of the crosslinking agent to be added is preferably 0.01 to 10 parts by weight, more preferably 0.1 to 7 parts by weight, based on 100 parts by weight of the resin (for example, the acrylic copolymer) as the main component of the pressure-sensitive adhesive layer. Is more preferred.

The pressure-sensitive adhesive layer may contain a silane coupling agent for the purpose of improving the adhesive strength. The silane coupling agent is not particularly limited, and examples thereof include epoxy silanes, acrylic silanes, methacryl silanes, amino silanes, and isocyanate silanes.

The pressure-sensitive adhesive layer may contain a coloring material for the purpose of imparting light-shielding properties. The coloring material is not particularly limited, and examples thereof include carbon black, aniline black, and titanium oxide. Among them, carbon black is preferred because it is relatively inexpensive and chemically stable.

The thickness of the pressure-sensitive adhesive layer is not particularly limited, but a preferable lower limit of the thickness of the pressure-sensitive adhesive layer on one side is 0.01 mm, and a preferable upper limit is 0.1 mm. By setting the thickness of the pressure-sensitive adhesive layer within this range, the double-sided pressure-sensitive adhesive tape according to one embodiment of the present invention can be suitably used for fixing portable electronic device components, vehicle-mounted electronic device components, and the like. From the viewpoint of being more suitably used for fixing the above components and the like, a more preferred lower limit of the thickness of the pressure-sensitive adhesive layer is 0.015 mm, and a more preferred upper limit is 0.09 mm.

The double-sided pressure-sensitive adhesive tape according to one embodiment of the present invention includes a first resin between the foam base material and the first pressure-sensitive adhesive layer, and between the foam base material and the second pressure-sensitive adhesive layer. It has a layer and a second resin layer, respectively (hereinafter, both are also simply referred to as “resin layer”). By having the resin layer, the double-sided pressure-sensitive adhesive tape according to one embodiment of the present invention employs the foam base material capable of exhibiting excellent stress relaxation and impact resistance, and the foam base material at the time of peeling. Can be separated without leaving any residue on the adherend, and excellent reworkability can be exhibited on both adhesive surfaces.

The resin layer has a tensile stress at break at 4 MPa or more. By using a resin layer having a tensile break stress of 4 MPa or more, excellent reworkability can be exhibited. From the viewpoint of further improving the reworkability, the tensile stress at break of the resin layer is preferably 5 MPa or more, and more preferably 15 MPa or more. Although the upper limit of the tensile stress at break of the resin layer is not particularly limited, the upper limit is substantially about 200 MPa.

It is preferable that at least one of the first resin layer and the second resin layer has a tensile elongation at break of 200% or more. By using a resin layer having a tensile elongation at break of 200% or more, more excellent reworkability can be exhibited. From the viewpoint of further improving the reworkability, the tensile elongation at break of the resin layer is preferably 300% or more, and more preferably 450% or more. Although the upper limit of the tensile elongation at break of the resin layer is not particularly limited, the upper limit is substantially about 1500%.

It is preferable that at least one of the first resin layer and the second resin layer has a tensile modulus of 200 MPa or less. By making at least one of the first resin layer and the second resin layer a flexible resin layer having a tensile modulus of 200 MPa or less, the flexibility of the entire double-sided pressure-sensitive adhesive tape is ensured, and the double-sided pressure-sensitive adhesive tape is formed into a roll. It becomes easy to wind up, and the handling is remarkably improved.

In addition, in this specification, the tensile break stress, the tensile break elongation, and the tensile elastic modulus mean the mechanical properties of the resin layer, and can be measured by a method according to JIS K7161.
Specifically, for example, a test piece is prepared by punching out the resin layer on a dumbbell using a punching blade “Tension No. 1 dumbbell shape” manufactured by Kobunshi Keiki Co., Ltd. The obtained test piece is measured at a tensile speed of 100 mm / min using, for example, “Autograph AGS-X” manufactured by Shimadzu Corporation to break the test piece. The tensile breaking stress is calculated from the breaking strength per unit area when the test piece breaks. From the elongation at break of the test piece, the tensile elongation at break is calculated by “(distance between grippers at break / distance between initial grippers) × 100”. The tensile modulus is calculated from the gradient of the tensile strength between strains of 1 to 3%.

The resin constituting the resin layer is not particularly limited, for example, a polyester resin such as polyethylene terephthalate, an acrylic resin, a polyethylene resin, a polypropylene resin, polyvinyl chloride, an epoxy resin, a silicone resin, a phenol resin, a polyimide, Examples include polyester and polycarbonate. Among them, acrylic resins, polyethylene resins, polypropylene resins, and polyester resins are preferred because of their excellent flexibility. Among the polyester resins, polyethylene terephthalate is preferred.

The resin constituting at least one of the first resin layer and the second resin layer is preferably made of a thermoplastic elastomer from the viewpoint of further improving stress relaxation, impact resistance and reworkability.
The thermoplastic elastomer includes a styrene (co) polymer, an olefin (co) polymer, a vinyl chloride (co) polymer, a polyetherester triblock (co) polymer, and a polyester (co) polymer. It may be a coalesced, urethane (co) polymer, amide (co) polymer or acrylic (co) polymer. Above all, it can exhibit the strength, elongation, flexibility, and self-adhesiveness as an elastic body, and can further improve the adhesion between the resin layer and the foam base material while exhibiting excellent reworkability. From the viewpoint that it is possible, it is preferable that the thermoplastic elastomer is an acrylic (co) polymer, a styrene (co) polymer or an olefin (co) polymer. Furthermore, an acrylic (co) polymer or a styrene (co) polymer is more preferable, and an acrylic (co) polymer is more preferable.
The proportion of the thermoplastic elastomer in the resin constituting at least one of the first resin layer and the second resin layer is preferably 70% by weight or more, more preferably 80% by weight or more, further preferably 90% by weight or more, particularly It is preferably at least 95% by weight and may be 100% by weight.

In a preferred embodiment of the present invention, the thermoplastic elastomer is preferably made of a block copolymer having a hard segment and a soft segment from the viewpoint of further improving stress relaxation, impact resistance and reworkability. The above-mentioned thermoplastic elastomer is a block copolymer having a hard segment and a soft segment.
In a further preferred embodiment of the present invention, the thermoplastic elastomer more preferably comprises a triblock copolymer having a hard segment and a soft segment. That is, the resin constituting at least one of the first resin layer and the second resin layer is made of a triblock copolymer having a hard segment and a soft segment, or a triblock having a hard segment and a soft segment. More preferably, it is a copolymer. By using such a triblock copolymer, it is possible to exhibit strength, elongation, flexibility, and self-adhesiveness as an elastic body, and while exhibiting excellent reworkability, a resin layer and a foam base material. And the adhesion to the substrate can be further improved.

Examples of the triblock copolymer include an acrylic triblock copolymer, a styrene triblock copolymer, a polyetherester triblock copolymer, a urethane copolymer, and a vinyl chloride copolymer. And amide copolymers.

The ratio of the hard segment in the block copolymer or the triblock copolymer is preferably 10% by weight or more and 70% by weight or less, more preferably 12% by weight or more and 65% by weight or less, The content is more preferably 14% by weight or more and 60% by weight or less, and particularly preferably 55% by weight or less. By setting the proportion of the hard segment in this range, the adhesion of the resin layer to the foam base material, particularly to the foam base material made of polyurethane foam or polyolefin foam is improved.
Above all, from the viewpoint of improving the adhesion of the resin layer to the foam base material, particularly the foam base material made of polyurethane foam or polyolefin foam, the ratio of the hard segment is 10% by weight or more and 60% by weight or less. The acrylic triblock copolymer is more preferable. If an acrylic triblock copolymer having excellent adhesion is used, it is not necessary to use an adhesive or the like in order to adhere the resin layer and the foam base material, and the thickness of the obtained double-sided pressure-sensitive adhesive tape can be reduced. it can.

Further, the thermoplastic elastomer is composed of a triblock copolymer and a diblock copolymer from the viewpoint of further enhancing stress relaxation, impact resistance and reworkability (the triblock copolymer and the diblock copolymer are Is also preferred).
In a preferred embodiment of the present invention, the proportion of the triblock copolymer in the thermoplastic elastomer is preferably 70% by weight or more, more preferably 80% by weight or more, further preferably 90% by weight or more, and particularly preferably. It is 95% by weight or more, and may be 100% by weight.

The components constituting the hard segment of the acrylic triblock copolymer are not particularly limited, but methyl methacrylate, ethyl methacrylate, n-butyl methacrylate, 2-ethylhexyl methacrylate, lauryl methacrylate, methacrylic acid Examples include alkyl and tridecyl methacrylate.
The component constituting the soft segment of the acrylic triblock copolymer is not particularly limited, and examples thereof include n-butyl acrylate, methyl acrylate, ethyl acrylate, and 2-ethylhexyl acrylate.
Among them, an acrylic triblock copolymer having a hard segment derived from methyl methacrylate and a soft segment derived from n-butyl acrylate is preferable.

When the acrylic triblock copolymer is a hard segment derived from methyl methacrylate and an acrylic triblock copolymer having a soft segment derived from n-butyl acrylate, in the triblock copolymer, A preferred lower limit of the ratio of the hard segment derived from methyl methacrylate is 22% by weight. A preferred upper limit is 50% by weight. Further, a more preferable lower limit of the ratio of the hard segment derived from methyl methacrylate is 24% by weight, and a more preferable upper limit is 48% by weight. When the ratio of the hard segment derived from the methyl methacrylate is within this range, it is possible to exhibit particularly excellent adhesion to the foam base material, and float between the foam base material and the resin layer. Can be prevented from occurring. In addition, it can exhibit excellent heat resistance and heat shrink resistance. For example, even when heat treatment is performed at 100 to 200 ° C. for about 10 to 30 minutes, it may be melted or wrinkled. Absent. Further, when the roll-shaped body is to be developed after being rolled, there is no possibility that the development cannot be performed due to blocking.

When the acrylic triblock copolymer is an acrylic triblock copolymer having a hard segment derived from methyl methacrylate and a soft segment derived from n-butyl acrylate, the weight of the triblock copolymer The average molecular weight is preferably 30,000 or more. When the weight average molecular weight of the triblock copolymer is 30,000 or more, particularly excellent adhesion to the foam base material can be exhibited, and reworkability of the double-sided pressure-sensitive adhesive tape can be exhibited. it can. The weight average molecular weight of the triblock copolymer is more preferably 50,000 or more. Although the upper limit of the weight average molecular weight of the triblock copolymer is not particularly limited, the upper limit is about 200,000 in consideration of handleability and the like.

The resin layer may be colored. By coloring the resin layer, a light-shielding property can be imparted to the double-sided pressure-sensitive adhesive tape.
The method of coloring the resin layer is not particularly limited. For example, a method of kneading particles such as carbon black and titanium oxide or fine bubbles into the resin constituting the resin layer, and applying ink to the surface of the resin layer Method and the like.

The resin layer may contain conventionally known additives such as an ultraviolet absorber, an antioxidant, an organic filler, and an inorganic filler, if necessary. When the resin constituting at least one of the first resin layer and the second resin layer is made of a thermoplastic elastomer, the resin may contain a resin other than the thermoplastic elastomer.

The thickness of the resin layer is not particularly limited, but a preferred lower limit is 5 μm and a preferred upper limit is 100 μm. By setting the thickness of the resin layer in this range, the double-sided pressure-sensitive adhesive tape according to one embodiment of the present invention can exhibit more excellent reworkability. From the viewpoint of further improving the reworkability, a more preferred lower limit of the thickness of the resin layer is 10 µm, and a more preferred upper limit is 70 µm.

The double-sided pressure-sensitive adhesive tape according to one embodiment of the present invention may have another layer other than the foam base material, the pressure-sensitive adhesive layer, and the resin layer, if necessary.

Although the thickness of the double-sided pressure-sensitive adhesive tape according to one embodiment of the present invention is not particularly limited, a preferable lower limit is 0.3 mm and a preferable upper limit is 3 mm. By setting the thickness of the double-sided pressure-sensitive adhesive tape according to one embodiment of the present invention within this range, it is possible to prevent the double-sided pressure-sensitive adhesive tape from withstanding a restoring force or a repulsive force and to be peeled off, while achieving sufficient adhesion and fixing. Excellent reworkability can be exhibited. From the viewpoint of suppressing the peeling of the double-sided tape and further improving the reworkability, the more preferable lower limit of the thickness of the double-sided pressure-sensitive adhesive tape according to one embodiment of the present invention is 0.4 mm, and the more preferable upper limit is 2.8 mm.

As a method for producing a double-sided pressure-sensitive adhesive tape according to one embodiment of the present invention, for example, the following method can be mentioned. First, a laminate of the foam base material and the first resin layer is manufactured, and a second resin layer is laminated on the laminate, and a first resin layer / foam base material / second resin layer is formed. To form a laminate.
Here, in order to laminate the resin layer and the foam base material, the resin layer preferably has self-adhesiveness (tackiness). In addition, the adhesiveness can be improved by pressing the resin layer and the foam base material with a heated laminator. Further, by inserting a resin layer during the step of foaming the base material to obtain a foam base material, the adhesion can be further improved. In addition, the surface of the resin sheet used as the resin layer or the foam substrate is subjected to a surface treatment (for example, a plasma treatment or a corona treatment) to improve the adhesion between the resin layer and the foam substrate. Can be. Further, when the resin layer has no self-adhesiveness, an adhesive layer may be provided between the foam base material and the resin layer and laminated. By modifying the polymer chain of the resin layer with a hydroxyl group or an acid group serving as a reaction point, the adhesion between the resin layer and the foam base material can be improved.
Next, a pressure-sensitive adhesive solution for forming the pressure-sensitive adhesive layer is prepared, the pressure-sensitive adhesive solution is applied to a release-treated surface of a release film, and the solvent in the solution is completely dried and removed to obtain a first pressure-sensitive adhesive. Form a layer. The first pressure-sensitive adhesive layer is provided on the first resin layer-side surface of the laminate composed of the first resin layer / foam base material / second resin layer, and the first pressure-sensitive adhesive layer is formed of the first pressure-sensitive adhesive layer. It is superposed in a state facing the resin layer side. On the other hand, a release film different from the above release film is prepared, an adhesive solution is applied to the release treated surface of the release film, and the solvent in the solution is completely dried and removed, thereby releasing the release film. To produce a laminated film having a second pressure-sensitive adhesive layer formed on the surface thereof. A second pressure-sensitive adhesive layer is formed on the second resin layer side surface of the laminate comprising the first resin layer / foam base material / second resin layer by applying the obtained laminated film to the second resin layer. A laminate comprising a first pressure-sensitive adhesive layer / a first resin layer / a foam base material / a second resin layer / a second pressure-sensitive adhesive layer is obtained by superimposing them in a state facing the side. Then, by pressing the obtained laminate with a rubber roller or the like, it has a first pressure-sensitive adhesive layer / first resin layer / foam base material / second resin layer / second pressure-sensitive adhesive layer, Moreover, a double-sided pressure-sensitive adhesive tape in which the surfaces of both pressure-sensitive adhesive layers are covered with a release film can be obtained. When the film is wound on a roll, the release film in contact with the second pressure-sensitive adhesive layer is peeled off, and the second pressure-sensitive adhesive layer can be wound inside. At this time, the release film in contact with the first pressure-sensitive adhesive layer needs to be subjected to a double-sided release treatment.

The application of the double-sided pressure-sensitive adhesive tape according to one embodiment of the present invention is not particularly limited, and is used, for example, for fixing portable electronic device components, vehicle-mounted electronic device components, and the like. The shape of the double-sided pressure-sensitive adhesive tape according to an embodiment of the present invention in these applications is not particularly limited, and examples thereof include a rectangle, a frame, a circle, an ellipse, and a donut.

The double-sided pressure-sensitive adhesive tape according to one embodiment of the present invention has excellent adhesion reliability in a state where a peeling stress is applied at a low speed such as a restoring force or a repulsive force, and is applied to a step, a corner, a non-planar part, or the like. It is preferable to be attached or used to fix the part in a deformed state. On the other hand, since it is excellent in reworkability, it can be suitably used for temporary fixing purposes. Furthermore, even if it is desired to peel off after lamination for some reason, there is no possibility that the foam base material is broken at the time of peeling and a residue remains on the adherend.

Articles using the double-sided pressure-sensitive adhesive tape according to one embodiment of the present invention include, for example, flat panel displays used in TVs, monitors, portable electronic devices, camera modules of portable electronic devices, internal members of portable electronic devices, and vehicles. Interior and exterior of home appliances (for example, TVs, air conditioners, refrigerators, etc.). Examples of the adherend of the double-sided pressure-sensitive adhesive tape according to one embodiment of the present invention include side panels, back panels, various nameplates, decorative films, decorative films, and the like of portable electronic devices.

According to the present invention, it is possible to provide a double-sided pressure-sensitive adhesive tape having excellent stress relaxation properties and impact resistance and excellent reworkability on both pressure-sensitive adhesive faces.

It is a schematic diagram which shows an example of the double-sided adhesive tape which concerns on one Embodiment of this invention.

Hereinafter, embodiments of the present invention will be described in more detail with reference to Examples, but the present invention is not limited to these Examples.

(Example 1)
(1) Preparation of First Resin Layer As the first resin layer, a 50 μm-thick polyethylene terephthalate (PET) sheet (X30, manufactured by Toray Industries, Inc.) was prepared. When measured by a method according to JIS K 7161, the PET sheet had a tensile stress at break at 180 MPa, an elongation at break at 138%, and a tensile modulus of elasticity of 4360 MPa.

(2) Production of polyurethane (PU) foam base material 100 parts by weight of a polyol (polyether polyol, weight average molecular weight 6000, number of hydroxyl groups 3, hydroxyl value 48 mgKOH / g) and an amine catalyst (Dabco LV33, manufactured by Sankyo Air Products Co., Ltd.) Was added and 1 part by weight of a foam stabilizer (SZ5740M, manufactured by Dow Corning Toray) was added and stirred. Thereto, polyisocyanate (Cosmonate TM-20, manufactured by Mitsui Chemicals, Inc.) was adjusted and charged to an isocyanate index of 80. Thereafter, the mixture was mixed and stirred with nitrogen gas so as to have a concentration of 0.2 g / cm ³ , to obtain a solution mixed with fine bubbles. The solution is applied to a predetermined thickness on a 50 μm-thick polyethylene terephthalate (PET) sheet (X30, manufactured by Toray Industries, Inc.) as a first resin layer using an applicator, and the foam material is reacted to form a 450 μm-thick. A laminate comprising a polyurethane (PU) foam substrate and a first resin layer was obtained.
The density of the obtained PU foam base material was measured using an electronic hydrometer (manufactured by Mirage, “ED120T”) according to JIS K-6767, and as a result, it was 0.3 g / cm ³ . Further, the 25% compressive strength of the obtained PU foam base material was measured according to JIS K 6254, and as a result, it was 15 kPa.

(3) Preparation of Second Resin Layer As the second resin layer, a sheet (LA2250, manufactured by Kuraray Co., Ltd.) made of 50 μm thick acrylic triblock copolymer a (acrylic TPE-a) was prepared.
In the acrylic TPE-a, the ratio of the hard segment derived from the polymethyl methacrylate resin is 30% by weight, the ratio of the soft segment derived from the polybutyl acrylate resin is 70% by weight, and the weight average molecular weight is 59000.
When measured by a method according to JIS K 7161, the acrylic TPE-a sheet had a tensile stress at break of 8.0 MPa, an elongation at break at 493%, and a tensile modulus of elasticity of 10.1 MPa.

(4) Preparation of Adhesive Solution 52 parts by weight of ethyl acetate was placed in a reactor equipped with a thermometer, a stirrer, and a cooling tube, and the atmosphere was replaced with nitrogen. Then, the reactor was heated to start refluxing. After 30 minutes from the boiling of the ethyl acetate, 0.08 parts by weight of azobisisobutyronitrile was added as a polymerization initiator. A monomer mixture comprising 70 parts by weight of butyl acrylate, 27 parts by weight of 2-ethylhexyl acrylate, 3 parts by weight of acrylic acid, and 0.2 parts by weight of 2-hydroxyethyl acrylate was uniformly and gradually dropped over 1 hour and 30 minutes. Reacted. Thirty minutes after the completion of the dropwise addition, 0.1 part by weight of azobisisobutyronitrile was added, the polymerization reaction was further performed for 5 hours, and ethyl acetate was added to the reactor and cooled while diluting to obtain a solid content of 40% by weight. A solution of the acrylic copolymer was obtained.
The weight-average molecular weight of the obtained acrylic copolymer measured by GPC using "2690 Separations Model" manufactured by Water as a column was 710,000. The ratio (Mw / Mn) of the weight average molecular weight (Mw) to the number average molecular weight (Mn) was 5.5.
15 parts by weight of a polymerized rosin ester having a softening point of 150 ° C., 10 parts by weight of a terpene phenol having a softening point of 145 ° C., and 10 parts by weight of a rosin ester having a softening point of 70 ° C. based on 100 parts by weight of a solid content of the obtained acrylic copolymer. Was added. Further, 30 parts by weight of ethyl acetate (manufactured by Fuji Chemical Co., Ltd.) and 3.0 parts by weight of an isocyanate-based cross-linking agent (trade name "Coronate L45" manufactured by Nippon Polyurethane Co., Ltd.) are added and stirred to obtain an adhesive solution. Was.

(5) Production of double-sided pressure-sensitive adhesive tape The acrylic resin triblock copolymer a as the second resin layer was formed on the PU foam substrate side of the laminate comprising the obtained PU foam substrate and the first resin layer. Were laminated and thermally laminated at 80 ° C. to form a laminate composed of a first resin layer / a foam base material / a second resin layer.
The above-mentioned pressure-sensitive adhesive solution is applied to a release-treated surface of a release liner made of polyethylene (PE) / high quality paper / polyethylene (PE) having been subjected to a release treatment with a thickness of 100 μm, and dried at 100 ° C. for 5 minutes. A first pressure-sensitive adhesive layer having a thickness of 50 μm was formed.

On the other hand, the above-mentioned pressure-sensitive adhesive solution is applied to the release-treated surface of a release liner made of polyethylene (PE) / high quality paper / polyethylene (PE) having a release treatment of 100 μm in thickness, and dried at 100 ° C. for 5 minutes. As a result, a second pressure-sensitive adhesive layer having a thickness of 50 μm was formed.
The release liner on which the second pressure-sensitive adhesive layer is formed is placed on the second resin layer-side surface of the laminate composed of the first resin layer / foam base / second resin layer by a second method. The first pressure-sensitive adhesive layer / first resin layer / foam base material / second resin layer / second pressure-sensitive adhesive layer is superposed on the pressure-sensitive adhesive layer in a state where the pressure-sensitive adhesive layer faces the second resin layer side. Was obtained. Then, by pressing the obtained laminate with a rubber roller, a first pressure-sensitive adhesive layer / first resin layer / foam base material / second resin layer / second pressure-sensitive adhesive layer is provided, and Thus, a double-sided pressure-sensitive adhesive tape having the surface of each pressure-sensitive adhesive layer covered with a release liner was obtained.

(Example 2)
A double-sided pressure-sensitive adhesive tape was prepared in the same manner as in Example 1, except that a sheet (LA2140e, manufactured by Kuraray Co., Ltd.) made of an acrylic triblock copolymer b (acrylic TPE-b) having a thickness of 50 μm was used as the second resin layer. Manufactured.
In the acrylic TPE-b, the ratio of the hard segment derived from the polymethyl methacrylate resin is 21% by weight, the ratio of the soft segment derived from the polybutyl acrylate resin is 79% by weight, and the weight average molecular weight is 73,000.
When measured by a method according to JIS K 7161, the acrylic TPE-b sheet had a tensile stress at break of 5.0 MPa, a tensile elongation at break of 602%, and a tensile modulus of elasticity of 1.0 MPa.

(Example 3)
A double-sided pressure-sensitive adhesive tape was prepared in the same manner as in Example 1 except that a 50 μm-thick acrylic triblock copolymer c (acrylic TPE-c) sheet (LA2330, manufactured by Kuraray Co., Ltd.) was used as the second resin layer. Manufactured.
In the acrylic TPE-c, the ratio of hard segments derived from polymethyl methacrylate resin is 23% by weight, the ratio of soft segments derived from polybutyl acrylate resin is 77% by weight, and the weight average molecular weight is 112000.
When measured by a method according to JIS K 7161, the acrylic TPE-c sheet had a tensile stress at break of 4.6 MPa, a tensile elongation at break of 550%, and a tensile modulus of elasticity of 0.6 MPa.

(Example 4)
A double-sided pressure-sensitive adhesive tape was prepared in the same manner as in Example 1 except that a sheet (LA4285, manufactured by Kuraray Co., Ltd.) made of an acrylic triblock copolymer d (acrylic TPE-d) having a thickness of 50 μm was used as the second resin layer. Manufactured.
In the acrylic TPE-d, the ratio of hard segments derived from polymethyl methacrylate resin is 55% by weight, the ratio of soft segments derived from polybutyl acrylate resin is 45% by weight, and the weight average molecular weight is 60,000.
When measured by a method according to JIS K 7161, the sheet made of the acrylic TPE-d had a tensile stress at break of 18.1 MPa, an elongation at break of 232%, and a tensile modulus of elasticity of 275.1 MPa.

(Example 5)
A double-sided pressure-sensitive adhesive tape was prepared in the same manner as in Example 1 except that a 50 μm-thick acrylic triblock copolymer e (acrylic TPE-e) sheet (LA2270, manufactured by Kuraray Co., Ltd.) was used as the second resin layer. Manufactured.
In the acrylic TPE-e, the ratio of the hard segment derived from the polymethyl methacrylate resin is 40% by weight, the ratio of the soft segment derived from the polybutyl acrylate resin is 60% by weight, and the weight average molecular weight is 60000.
When measured by a method according to JIS K 7161, the sheet made of the acrylic TPE-e had a tensile break stress of 11.4 MPa, a tensile break elongation of 434%, and a tensile modulus of 51.8 MPa.

(Example 6)
As the second resin layer, an acrylic triblock copolymer e (acrylic TPE-e) (LA2270, manufactured by Kuraray) and an acrylic diblock copolymer f (acrylic TPE-f) (manufactured by Kuraray) having a thickness of 50 μm , LA1114) in the same manner as in Example 1 except that a sheet having a weight ratio of 85/15 was used to produce a double-sided pressure-sensitive adhesive tape.
In the acrylic TPE-e, the ratio of the hard segment derived from the polymethyl methacrylate resin is 40% by weight, the ratio of the soft segment derived from the polybutyl acrylate resin is 60% by weight, and the weight average molecular weight is 60000.
When measured by a method according to JIS K 7161, the sheet composed of the acrylic TPE-e and the acrylic TPE-f had a stress at break at 4.3 MPa, an elongation at break at 660%, and a tensile modulus of elasticity of 0.8 MPa. Met.

(Example 7)
A double-sided pressure-sensitive adhesive tape was produced in the same manner as in Example 1 except that a sheet made of a styrene / acrylic triblock copolymer (styrene / acrylic TPE) having a thickness of 50 μm was used as the second resin layer.
In the styrene / acrylic TPE, the ratio of a hard segment derived from a polystyrene resin is 17% by weight, the ratio of a soft segment derived from a polybutyl acrylate resin is 83% by weight, and the weight average molecular weight is 240,000.
When measured by a method according to JIS K 7161, the sheet composed of the styrene / acrylic TPE had a tensile stress at break at 7.6 MPa, an elongation at tensile break at 650%, and a tensile modulus of elasticity of 1.9 MPa.

(Example 8)
Double-sided adhesive in the same manner as in Example 1 except that a 50 μm-thick sheet made of a styrene-based triblock copolymer a (styrene TPE-a) (# 3620, manufactured by Zeon Corporation) was used as the second resin layer. Tape was manufactured.
In the styrene TPE-a, the ratio of a hard segment derived from styrene is 14% by weight, and the ratio of a soft segment derived from isoprene is 86% by weight. It also contains a diblock component of the same composition at a GPC area ratio of 12%.
When measured by a method according to JIS K 7161, the sheet made of the styrene TPE-a had a tensile stress at break at 24.0 MPa, an elongation at tensile break at 1200%, and a tensile modulus of elasticity of 40.0 MPa.

(Example 9)
Double-sided adhesive in the same manner as in Example 1 except that a sheet (styrene 3PE-b) made of styrene-based triblock copolymer b (styrene TPE-b) having a thickness of 50 μm was used as the second resin layer. Tape was manufactured.
In the styrene TPE-b, the ratio of a hard segment derived from styrene is 14% by weight, and the ratio of a soft segment derived from isoprene is 86% by weight. It also contains a diblock component of the same composition at a GPC area ratio of 26%.
When measured by a method according to JIS K 7161, the sheet made of the styrene TPE-b had a stress at break at tensile strength of 19.0 MPa, an elongation at break at 1300%, and a tensile modulus of elasticity of 38.0 MPa.

(Example 10)
Same as Example 1 except that a 50 μm-thick polyetherester-based block copolymer a (polyetherester TPE-a) sheet (manufactured by Du Pont-Toray Co., Ltd., # 5557) was used as the second resin layer. To produce a double-sided pressure-sensitive adhesive tape.
The polyetherester TPE-a has a hard segment derived from PBT and a soft segment derived from polyether.
When measured by a method according to JIS K 7161, the sheet made of the polyetherester TPE-a had a stress at tensile break at 31.4 MPa, an elongation at tensile break at 390%, and a tensile modulus of elasticity of 137.0 MPa. .

(Example 11)
Same as Example 1 except that a 50 μm-thick polyetherester-based block copolymer b (polyetherester TPE-b) sheet (manufactured by Toray DuPont, # 7247) was used as the second resin layer. To produce a double-sided pressure-sensitive adhesive tape.
The polyetherester TPE-b has a hard segment derived from PBT and a soft segment derived from polyether.
When measured by a method according to JIS K 7161, the sheet made of the polyetherester TPE-b had a tensile stress at break of 36.3 MPa, a tensile elongation at break of 260%, and a tensile modulus of elasticity of 422.0 MPa. .

(Example 12)
A double-sided pressure-sensitive adhesive tape was produced in the same manner as in Example 1, except that a sheet (1198 ATR, manufactured by BASF) comprising a urethane-based block copolymer (urethane TPE) having a thickness of 60 μm was used as the second resin layer.
When measured by a method according to JIS K 7161, the urethane TPE sheet had a tensile stress at break of 57.1 MPa, an elongation at break of 406%, and a tensile modulus of elasticity of 108.0 MPa.

(Example 13)
As the second resin layer, a sheet (made by Toyobo Co., Ltd., # 60) made of biaxially oriented polypropylene (OPP) having a thickness of 60 μm is used, and an adhesive layer is laminated on the second resin layer and the foam base material. A double-sided pressure-sensitive adhesive tape was produced in the same manner as in Example 1 except that the two layers were laminated.
When measured by a method according to JIS K 7161, the OPP sheet had a tensile stress at break at 140.0 MPa, an elongation at break at 210%, and a tensile modulus of elasticity of 2100.0 MPa.

(Example 14)
As the second resin layer, a 25 μm-thick polyethylene terephthalate (PET) sheet (manufactured by Toyobo Co., Ltd., # 25) is used, and the second resin layer and the foam base material are laminated via an adhesive layer. A double-sided pressure-sensitive adhesive tape was produced in the same manner as in Example 1 except that the tape was laminated.
When measured by a method according to JIS K 7161, the PET sheet had a tensile stress at break at 177.0 MPa, an elongation at break at 132%, and a tensile modulus of elasticity of 2376.0 MPa.

(Comparative Example 1)
As the second resin layer, a pulp nonwoven fabric sheet having a thickness of 50 μm (manufactured by Ritosho Co., Ltd., SPC) was used, and the second resin layer and the foam base material were laminated via an adhesive layer. Produced a double-sided pressure-sensitive adhesive tape in the same manner as in Example 1.
When measured by a method according to JIS K 7161, the pulp nonwoven fabric sheet had a tensile stress at break of 3.7 MPa, an elongation at break at 102%, and a tensile modulus of elasticity of 160.0 MPa.

(Comparative Example 2)
A double-sided pressure-sensitive adhesive tape was produced in the same manner as in Example 1 except that an acrylic pressure-sensitive adhesive having a thickness of 50 μm was used as the second resin layer.
When measured by a method according to JIS K 7161, the layer made of the acrylic pressure-sensitive adhesive had a tensile stress at break at 0.5 MPa, an elongation at break at 825%, and a tensile modulus of elasticity of 0.2 MPa.
The acrylic pressure-sensitive adhesive was prepared by the following method.
52 parts by weight of ethyl acetate was placed in a reactor equipped with a thermometer, a stirrer, and a cooling tube, and the atmosphere was replaced with nitrogen. Then, the reactor was heated to start refluxing. After 30 minutes from the boiling of the ethyl acetate, 0.08 parts by weight of azobisisobutyronitrile was added as a polymerization initiator. Here, a monomer mixture (butyl acrylate (BA) 60 parts by weight, 2-ethylhexyl acrylate (2EHA) 36.9 parts by weight, acrylic acid (AAc) 3 parts by weight, and 2-hydroxyethyl acrylate (2HEA) ) Was uniformly and gradually dropped over 1 hour and 30 minutes to cause a reaction. Thirty minutes after the completion of the dropwise addition, 0.1 part by weight of azobisisobutyronitrile was added, and the polymerization reaction was further performed for 5 hours. I got
Ethyl acetate was added to 100 parts by weight of the nonvolatile content of the obtained acrylic copolymer-containing solution and stirred, and a total of 30 parts by weight of a tackifier resin (10 parts of hydrogenated rosin-based resin, 10 parts of rosin ester-based resin, Terpene phenol resin (10 parts) was added and stirred to obtain an adhesive having a nonvolatile content of 30% by weight.

(Comparative Example 3)
A double-sided adhesive tape was prepared in the same manner as in Example 1 except that a sheet made of an acrylic diblock copolymer f (acrylic TPE-f) (LA1114, manufactured by Kuraray Co., Ltd.) having a thickness of 50 μm was used as the second resin layer. Manufactured.
When measured by a method according to JIS K 7161, the acrylic TPE-f sheet had a tensile stress at break of 1.2 MPa, a tensile elongation at break of 990%, and a tensile modulus of elasticity of 0.3 MPa.

(Evaluation)
The following evaluations were performed on the double-sided pressure-sensitive adhesive tapes obtained in Examples and Comparative Examples. The results are shown in Table 1.

(1) Evaluation of Flexibility The obtained double-sided pressure-sensitive adhesive tape (release liner / first pressure-sensitive adhesive layer / first resin layer / foam base material / second resin layer / second pressure-sensitive adhesive layer) was used. A roll was obtained by wrapping the paper with a 3 inch diameter paper core so that the second pressure-sensitive adhesive layer side was inside.
The side surface and the surface layer of the obtained roll were visually observed. Furthermore, after pulling out the double-sided pressure-sensitive adhesive tape from the roll-shaped body, it was visually observed from the second pressure-sensitive adhesive layer side, and evaluated according to the following criteria.
：: No wrinkles or breaks were observed in all the confirmed locations.
Δ: Wrinkles and breaks were observed in some of the confirmed locations.
X: Wrinkles and breaks were observed at all the confirmed locations.

(2) Evaluation of reworkability The obtained double-sided pressure-sensitive adhesive tape was cut into a size of 5 mm wide x 100 mm long and 10 mm wide x 100 mm long to prepare a 5 mm wide sample and a 10 mm wide sample.
The release liner on the first pressure-sensitive adhesive layer side of each of the obtained samples was peeled off, and the first pressure-sensitive adhesive layer side was stuck on a glass plate (width 50 mm, length 125 mm) having a thickness of 2 mm, and was placed on a double-sided pressure-sensitive adhesive tape. After reciprocating a 2 kg rubber roller once at a speed of 300 mm / min, it was left for 24 hours in an environment of 23 ° C. and 50% relative humidity. Next, the layers of the foam base material are torn apart, and the second pressure-sensitive adhesive layer, the second resin layer, and a part of the foam base material are removed from the double-sided pressure-sensitive adhesive tape, and then the remaining portion of the double-sided pressure-sensitive adhesive tape is removed. Was pulled from the horizontal direction at an angle of 30 ° at a speed of 300 mm / min to peel off the remaining portion of the double-sided adhesive tape from the glass plate. The reworkability on the first pressure-sensitive adhesive layer side was evaluated according to the following criteria. The same evaluation was performed on the second pressure-sensitive adhesive layer side.
：: The remaining portion of the double-sided adhesive tape could be removed.
Δ: The double-sided pressure-sensitive adhesive tape was partially removed during the peeling, but could be removed.
X: The remaining part of the double-sided adhesive tape could not be removed.

According to the present invention, it is possible to provide a double-sided pressure-sensitive adhesive tape having excellent stress relaxation properties and impact resistance and excellent reworkability on both pressure-sensitive adhesive faces.

DESCRIPTION OF SYMBOLS 1 Double-sided adhesive tape 2 Foam base material 31 First adhesive layer 32 Second adhesive layer 41 First resin layer 42 Second resin layer

Claims (12)

A foam substrate, a double-sided pressure-sensitive adhesive tape having a first pressure-sensitive adhesive layer and a second pressure-sensitive adhesive layer on both surfaces of the foam substrate, respectively.
A first resin layer having a tensile stress at break of 4 MPa or more, between the foam base material and the first pressure-sensitive adhesive layer, and between the foam base material and the second pressure-sensitive adhesive layer; A double-sided pressure-sensitive adhesive tape having a second resin layer. The double-sided pressure-sensitive adhesive tape according to claim 1, wherein at least one of the first resin layer and the second resin layer has a tensile elongation at break of 200% or more. The double-sided pressure-sensitive adhesive tape according to claim 1, wherein at least one of the first resin layer and the second resin layer has a tensile modulus of 200 MPa or less. 4. The double-sided pressure-sensitive adhesive tape according to claim 1, wherein at least one of the first resin layer and the second resin layer is made of a thermoplastic elastomer. The double-sided pressure-sensitive adhesive tape according to claim 4, wherein the thermoplastic elastomer comprises a block copolymer having a hard segment and a soft segment. The double-sided pressure-sensitive adhesive tape according to claim 4, wherein the thermoplastic elastomer comprises a triblock copolymer having a hard segment and a soft segment. 7. The double-sided pressure-sensitive adhesive tape according to claim 5, wherein a ratio of the hard segment in the block copolymer or the triblock copolymer is 10% by weight or more and 70% by weight or less. The double-sided pressure-sensitive adhesive tape according to claim 4, wherein the thermoplastic elastomer has a triblock copolymer content of 70% by weight or more. 9. The double-sided pressure-sensitive adhesive tape according to claim 4, wherein the thermoplastic elastomer comprises a triblock copolymer and a diblock copolymer. 10. The double-sided pressure-sensitive adhesive tape according to claim 4, wherein the thermoplastic elastomer comprises an acrylic copolymer. The triblock copolymer is an acrylic triblock copolymer, and the acrylic triblock copolymer has a hard segment derived from methyl methacrylate and a soft segment derived from n-butyl acrylate, The ratio of the hard segment derived from methyl methacrylate in the acrylic triblock copolymer is 22% by weight or more and 50% by weight or less, and the weight average molecular weight of the acrylic triblock copolymer is 3%. The double-sided pressure-sensitive adhesive tape according to claim 6, 7, 8, 9, or 10, wherein the thickness is not less than 10,000. The double-sided pressure-sensitive adhesive tape according to any one of claims 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, and 11, wherein the foam base material is made of a polyurethane foam or a polyolefin foam.

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