TWI802564B - double sided adhesive tape - Google Patents

Abstract

The object of the present invention is to provide a double-sided adhesive tape having excellent stress relaxation and impact resistance and excellent reworkability of both adhesive surfaces. The present invention is a double-sided adhesive tape, which has a foam substrate, and a first adhesive layer and a second adhesive layer respectively located on both sides of the foam substrate, and on the foam substrate Between the first adhesive layer and the foam substrate and the second adhesive layer, there are a first resin layer and a second resin layer having a tensile fracture point stress of 4 MPa or more, respectively.

Description

double sided adhesive tape

The present invention relates to a double-sided adhesive tape with excellent stress relaxation and impact resistance and excellent reworkability of both adhesive surfaces.

For portable electronic devices such as mobile phones and mobile information terminals (Personal Digital Assistants, PDAs), double-sided adhesive tapes are used for assembly (for example, Patent Documents 1 and 2). In addition, the double-sided adhesive tape can also be used for fixing vehicle-mounted electronic equipment parts such as vehicle-mounted panels to the vehicle body.

[Prior Art Literature]

[Patent Document]

Patent Document 1: Japanese Patent Laid-Open No. 2009-242541

Patent Document 2: Japanese Patent Laid-Open No. 2009-258274

High adhesive force is required for double-sided adhesive tapes used for fixing portable electronic device parts and vehicle-mounted electronic device parts, etc. Furthermore, in recent years, portable electronic devices, vehicle-mounted electronic devices, etc. tend to become more complicated in shape with higher functions, so there are double-sided adhesive tapes attached to steps, corners, and non-planar portions. Waiting for use. In this case, the double-sided adhesive tape is fixed in a deformed state, so there is a force to restore the original shape, that is, a restoring force or a rebound force, and the double-sided adhesive tape may be peeled off as time passes. Condition. Especially in the case of fixing the parts in the state of deformation, because the parts themselves want to return to their original shape, there is a restoring force or rebound force applied to the double-sided adhesive tape, resulting in insufficient fixing or peeling of the double-sided adhesive tape Condition. In order to prevent such peeling due to the restoring force or rebounding force, excellent stress relaxation is required for the double-sided adhesive tape. Moreover, there are cases where impact resistance is required for double-sided adhesive tapes.

A double-sided adhesive tape using a foam base material is known as a double-sided adhesive tape having excellent stress relaxation properties and excellent impact resistance. However, when the conventional double-sided adhesive tape using a foam base is used for temporary fixation, or when it is intended to be peeled off after bonding in some cases, there is a foam when peeling. In the case where the base material is cracked and residues remain on the adherend, there is a problem of poor reworkability. Especially for the double-sided adhesive tape, the reworkability of the two adhesive surfaces is required.

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

The present invention is a double-sided adhesive tape, which has a foam substrate, and a first adhesive layer and a second adhesive layer respectively located on both sides of the foam substrate, and on the foam substrate Between the first adhesive layer and the foam substrate and the second adhesive layer, there are a first resin layer and a second resin layer having a tensile fracture point stress of 4 MPa or more, respectively.

Hereinafter, the present invention will be described in detail.

For a double-sided adhesive tape having a foam base material and a first adhesive layer and a second adhesive layer located on both sides of the foam base material respectively, the present inventors applied a double-sided adhesive tape between the foam base material and the second adhesive layer. 1. A first resin layer and a second resin layer each having a tensile breaking point stress of a certain value or more are disposed between the adhesive layers, and between the foam substrate and the second adhesive layer. The inventors of the present invention have found that by arranging such a first resin layer and a second resin layer, it is possible to use a foam base material that exhibits excellent stress relaxation and impact resistance, and to exhibit excellent rework on both adhesive surfaces. properties, thus completing the present invention.

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

A double-sided adhesive tape according to an embodiment of the present invention has a foam substrate, and a first adhesive layer and a second adhesive layer respectively positioned on both sides of the foam substrate.

By using the above-mentioned foam base material, the double-sided adhesive tape according to one embodiment of the present invention can exhibit excellent stress relaxation properties and impact resistance. The above-mentioned foam substrate may have an open-cell structure or an closed-cell structure, and preferably has an open-cell structure. By using a foam base material with an open cell structure, more excellent stress relaxation and impact resistance can be exhibited. The above-mentioned foam substrate may have a single-layer structure or a multi-layer structure.

The said foam base material is not specifically limited, For example, a polyurethane foam, a polyolefin foam, a rubber-type resin foam, an acrylic foam, etc. are mentioned. Among these, a polyurethane foam or a polyolefin foam is preferable in terms of being easy to form an open cell structure and exhibiting excellent stress relaxation properties and impact resistance.

The density of the above-mentioned foam substrate is not particularly limited, but the lower limit is preferably 0.03 g/cm ³ , and the upper limit is 0.8 g/cm ³ . By making the density of the said foam base material into this range, while maintaining the intensity|strength of a double-sided adhesive tape, excellent stress relaxation property and impact resistance can be exhibited. From the standpoint of the strength, stress relaxation and impact resistance of the double-sided adhesive tape, the lower limit of the above substrate is more preferably 0.1g/cm ³ , the upper limit is more preferably 0.7g/cm ³ , and the lower limit is more preferably 0.15 g/cm ³ , and a more preferable upper limit is 0.5 g/cm ³ , a more preferable lower limit is 0.2 g/cm ³ , and a more preferable upper limit is 0.4 g/cm ³ .

In addition, density can be measured using the electronic pycnometer (for example, the product made by MIRAGE company, "ED120T") based on JISK6767.

The 25% compressive strength of the foam base material is not particularly limited, the lower limit is preferably 1 kPa, and the upper limit is 100 kPa. By making the 25% compressive strength of the said foam base material into this range, while maintaining the intensity|strength of a double-sided adhesive tape, excellent stress relaxation property and impact resistance can be exhibited. From the point of view of further improving the strength, stress relaxation and impact resistance of the double-sided adhesive tape, the more preferable lower limit of the 25% compressive strength of the above substrate is 3kPa, the more preferable upper limit is 50kPa, and the more preferable lower limit is 5kPa, Further, a preferable upper limit is 40 kPa.

In addition, 25% compressive strength can be calculated|required by measuring based on JISK6254.

The shear storage elastic modulus of the above-mentioned foam substrate is not particularly limited, it is preferably measured by a dynamic viscoelastic device, and the frequency in the main curve synthesized at a reference temperature of 23°C is 1.0×10 ^-4 ~1.0× The maximum value of the shear storage elastic modulus in the 10 ^-5 Hz region is 1.0×10 ⁵ Pa or less. The above-mentioned frequency region is the frequency corresponding to the peeling stress at low speed generated when the restoring force or rebounding force is applied to the double-sided adhesive tape. If the maximum value of the shear storage elastic modulus in the above-mentioned frequency region is 1.0×10 ⁵ Pa or less, the stress when the restoring force or rebounding force is applied to the double-sided adhesive tape by the above-mentioned foam base material is relaxed, so that It is not easy to transfer to the adhesive layer, so it can improve the stress relaxation and impact resistance of the double-sided adhesive tape.

Furthermore, the shear storage elastic modulus can use a dynamic viscoelasticity measuring device (for example, DVA-200 manufactured by IT Meter, etc.) and set the heating rate at 5°C/min, within the range of -60°C to 250°C To measure. When measuring the shear storage elastic modulus, in order to suppress the deviation of the sample during the measurement, an adhesive is applied on both sides of the above-mentioned base material and measured. Such an adhesive is not particularly limited, and the thickness of the adhesive applied on both sides of the above-mentioned base material is adjusted so that it becomes 15% or less of the thickness of the above-mentioned base material, and the measurement is performed. By setting the thickness of the adhesive to less than 15% of the thickness of the above-mentioned substrate, the influence of the adhesive can be eliminated as much as possible to measure the shear storage modulus of the above-mentioned substrate.

The thickness of the above-mentioned foam substrate is not particularly limited, but the lower limit is preferably 0.2 mm, and the upper limit is 2.9 mm. By setting the thickness of the above-mentioned foam base material within this range, the double-sided adhesive tape according to an embodiment of the present invention can be preferably used for portable electronic device parts, automotive electronic device parts, etc. fixed. From the viewpoint of being more preferably used for fixing the above-mentioned components, the more preferable lower limit of the thickness of the above-mentioned foam base material is 0.3 mm, and the more preferable upper limit is 2.5 mm.

The above-mentioned first adhesive layer and second adhesive layer (hereinafter, both are also collectively referred to simply as "adhesive layer") may have the same composition, or may have different compositions respectively. The above-mentioned adhesive layer is not particularly limited, and examples thereof include an acrylic adhesive layer, a rubber-based adhesive layer, a urethane adhesive layer, and a silicone-based adhesive layer. Among them, an acrylic adhesive layer containing an acrylic copolymer is preferable in that it is relatively stable against light, heat, moisture, etc. and can be adhered to various adherends (low selectivity of adherends).

The acrylic copolymer constituting the acrylic adhesive layer is preferably obtained by copolymerizing a monomer mixture including butyl acrylate and 2-ethylhexyl acrylate. The preferred lower limit of the above-mentioned butyl acrylate content in the total monomer mixture is 40% by weight, and the preferred upper limit is 80% by weight. By making content of the said butyl acrylate into this range, high adhesive force and viscosity can be compatible. The preferred lower limit of the content of the above-mentioned 2-ethylhexyl acrylate in the total monomer mixture is 10% by weight, and the preferred upper limit is 40% by weight. By making content of the said 2-ethylhexyl acrylate into this range, high adhesive force can be exhibited.

The above monomer mixture may optionally contain other copolymerizable monomers other than butyl acrylate and 2-ethylhexyl acrylate. Examples of other polymerizable monomers that can be copolymerized include: alkyl (meth)acrylates having 1 to 3 carbon atoms in the alkyl group, and alkyl (meth)acrylates having 13 to 18 carbon atoms in the alkyl group. base esters, functional monomers, etc.

Examples of alkyl (meth)acrylates having 1 to 3 carbon atoms in the alkyl group include methyl (meth)acrylate, ethyl (meth)acrylate, n-propyl (meth)acrylate, Isopropyl (meth)acrylate, etc. Examples of the alkyl (meth)acrylate having 13 to 18 carbon atoms in the alkyl group include tridecyl methacrylate, stearyl (meth)acrylate, and the like. Examples of the functional monomers include: hydroxyalkyl (meth)acrylate, glycerin dimethacrylate, glycidyl (meth)acrylate, 2-methacryloxyethyl isocyanate , (meth)acrylic acid, itaconic acid, maleic anhydride, crotonic acid, maleic acid, fumaric acid, etc.

In order to obtain the said acrylic copolymer by copolymerizing the said monomer mixture, what is necessary is just to make the said monomer mixture radically react in presence of a polymerization initiator. As a method of subjecting the monomer mixture to a radical reaction, that is, a polymerization method, conventionally known methods can be used, for example, solution polymerization (boiling point polymerization or constant temperature polymerization), emulsion polymerization, suspension polymerization, block polymerization, etc. .

The preferable lower limit of the weight average molecular weight (Mw) of the said acrylic copolymer is 400,000, and the preferable upper limit is 1.5 million. By making the weight average molecular weight of the said acrylic copolymer into this range, high adhesive force can be exhibited. A more preferable lower limit of the above-mentioned weight average molecular weight is 500,000, and a more preferable upper limit is 1.4 million.

In addition, weight average molecular weight (Mw) means the weight average molecular weight of standard polystyrene conversion obtained by GPC (Gel Permeation Chromatography: gel permeation chromatography).

The preferable upper limit of the ratio (Mw/Mn) of the weight average molecular weight (Mw) to the number average molecular weight (Mn) of the said acrylic copolymer is 10.0. When Mw/Mn exceeds 10.0, there are many low-molecular components, and the above-mentioned acrylic adhesive layer softens at high temperature, and block strength may fall and adhesive strength may fall. A more preferable upper limit of Mw/Mn is 3.0.

The above-mentioned adhesive layer may contain an adhesive resin.

Examples of the tack-imparting resin include rosin ester resins, hydrogenated rosin resins, terpene resins, terpene phenol resins, lavone-indene resins, alicyclic saturated hydrocarbon resins, and C5 petroleum resins. , C9 petroleum resin, C5-C9 copolymer petroleum resin, etc. These tack-providing resins may be used alone, or may use 2 or more types together.

The content of the tack-imparting resin is not particularly limited, but the lower limit is preferably 10 parts by weight, and the upper limit is 60 parts by weight relative to 100 parts by weight of the resin (eg, acrylic copolymer) that is the main component of the adhesive layer. When content of the said tackiness provision resin is less than 10 weight part, the adhesive force of the said adhesive agent layer may fall. When content of the said tackiness imparting resin exceeds 60 weight part, the said adhesive agent layer may harden and adhesive force or viscosity may fall.

The adhesive layer preferably has a cross-linked structure formed between main chains of resins (for example, the acrylic copolymer, the adhesion-imparting resin, etc.) constituting the adhesive layer by adding a cross-linking agent. The said crosslinking agent is not specifically limited, For example, an isocyanate type crosslinking agent, an aziridine type crosslinking agent, an epoxy type crosslinking agent, a metal chelate type crosslinking agent etc. are mentioned. Among them, an isocyanate-based crosslinking agent is preferred. By adding an isocyanate-based cross-linking agent to the above-mentioned adhesive layer, the isocyanate group of the isocyanate-based cross-linking agent and the resin (such as the above-mentioned acrylic copolymer, the above-mentioned tackifying resin, etc.) constituting the above-mentioned adhesive layer The alcoholic hydroxyl group reacts to ease the crosslinking of the above-mentioned adhesive layer. Therefore, the above-mentioned adhesive layer can disperse the intermittently increased peeling stress, so that the adhesive force of the double-sided adhesive tape can be further improved.

The amount of the crosslinking agent 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 above-mentioned acrylic copolymer) that is the main component of the adhesive layer.

In order to improve the adhesion, the above-mentioned adhesive layer may also contain a silane coupling agent. The said silane coupling agent is not specifically limited, For example, epoxy silanes, acryl silanes, methacryl silanes, amino silanes, isocyanato silanes etc. are mentioned.

In order to provide light-shielding property, the said adhesive agent layer may contain a coloring material. The said coloring material is not specifically limited, For example, carbon black, aniline black, titanium oxide, etc. are mentioned. Among them, carbon black is preferable in terms of being relatively cheap and chemically stable.

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

A double-sided adhesive tape according to an embodiment of the present invention has a first resin layer and a first resin layer between the foam base material and the first adhesive layer, and between the foam base material and the second adhesive layer, respectively. The second resin layer (hereinafter, both are also simply referred to as "resin layer"). By having the above-mentioned resin layer, the double-sided adhesive tape according to an embodiment of the present invention can use the above-mentioned foam base material that exhibits excellent stress relaxation and impact resistance, and the above-mentioned foam base material can be peeled off. No cracking occurs, and it can be peeled off without leaving any residue on the adherend, and it can exert excellent reworkability on both adhesive surfaces.

The tensile breaking point stress of the above-mentioned resin layer is 4 MPa or more. Excellent reworkability can be exhibited by using a resin layer with a tensile breaking point stress of 4 MPa or more. From the viewpoint of further improving reworkability, the tensile breaking point stress of the resin layer is preferably 5 MPa or more, more preferably 15 MPa or more. The upper limit of the tensile breaking point stress of the resin layer is not particularly limited, but the actual upper limit is about 200 MPa.

The tensile elongation at break of at least one of the first resin layer and the second resin layer is preferably 200% or more. By using a resin layer with a tensile elongation at breaking point of 200% or more, more excellent reworkability can be exhibited. From the viewpoint of further improving reworkability, the tensile elongation at break of the resin layer is preferably at least 300%, more preferably at least 450%. The upper limit of the tensile elongation at break point of the resin layer is not particularly limited, but the actual upper limit is about 1500%.

The tensile modulus of at least one of the first resin layer and the second resin layer is preferably 200 MPa or less. By making at least one of the first resin layer and the second resin layer a soft resin layer with a tensile modulus of 200 MPa or less, the overall flexibility of the double-sided adhesive tape is ensured, and the double-sided adhesive tape can be rolled easily. Taken in a roll form, the handleability is particularly improved.

In addition, in this specification, tensile breaking point stress, tensile breaking point elongation, and tensile elastic modulus mean the mechanical characteristic of a resin layer, and can be measured by the method based on JISK7161.

Specifically, for example, a test piece is produced by punching the above-mentioned resin layer on a dumbbell using a punching knife "Draw I Type Dumbbell" manufactured by Polymer Keiki Co., Ltd. or the like. For the obtained test piece, for example, "Autograph AGS-X" manufactured by Shimadzu Corporation is used for measurement at a tensile speed of 100 mm/min, and the test piece is broken. The tensile breaking stress was calculated from the breaking strength per unit area when the test piece was broken. According to the elongation of the test piece at breakage, the elongation at the tensile breaking point was calculated by "(distance between grippers at breakage/distance between initial grippers) x 100". The tensile elastic modulus was calculated from the slope of the tensile strength between 1~3% strain.

The resin constituting the resin layer is not particularly limited, and examples thereof include polyester resins such as polyethylene terephthalate, acrylic resins, polyethylene resins, polypropylene resins, polyvinyl chloride, and epoxy resins. , Polysiloxane resin, phenol resin, polyimide, polyester, polycarbonate, etc. Among them, acrylic resins, polyethylene resins, polypropylene resins, and polyester resins are preferable in terms of excellent flexibility. Among polyester-based resins, polyethylene terephthalate is preferred.

The resin constituting at least one of the first resin layer and the second resin layer is preferably composed of a thermoplastic elastomer from the viewpoint of further improving stress relaxation properties, impact resistance, and reworkability.

The above-mentioned thermoplastic elastomers can be styrene (co)polymers, olefin (co)polymers, vinyl chloride (co)polymers, polyether ester triblock (co)polymers, polyester ( Co)polymer, urethane (co)polymer, amide (co)polymer or acrylic (co)polymer. Among them, the above-mentioned thermoplastic elastomers can exhibit the strength, elongation, flexibility, and self-adhesiveness as an elastomer, can exhibit excellent reworkability, and can further improve the adhesion between the resin layer and the foam substrate. It is preferably 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 still 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 at least 70% by weight, more preferably at least 80% by weight, further preferably at least 90% by weight, More preferably, it is 95 weight% or more, and may be 100 weight%.

In a preferred embodiment of the present invention, the above-mentioned thermoplastic elastomer is preferably composed of a block copolymer having a hard segment and a soft segment in terms of further improving stress relaxation, impact resistance and reworkability. To constitute, for example, the above-mentioned thermoplastic elastomer system has a block copolymer of a hard segment and a soft segment.

In a further preferred embodiment of the present invention, the above-mentioned thermoplastic elastomer is more preferably composed of a tri-block 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 more preferably composed of a triblock copolymer having a hard segment and a soft segment, or a triblock copolymer having a hard segment and a soft segment. triblock copolymer. By using such a triblock copolymer, the strength, elongation, flexibility, and self-adhesiveness of an elastomer can be exhibited, excellent reworkability can be exhibited, and the adhesion between the resin layer and the foam substrate can be further improved.

Examples of the triblock copolymers include: acrylic triblock copolymers, styrene triblock copolymers, polyether ester triblock copolymers, urethane copolymers, vinyl chloride copolymers substances, amide-based copolymers, etc.

The ratio of the hard segment in the above-mentioned block copolymer or the above-mentioned tri-block 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, still more preferably 14% by weight or less. % by weight to not more than 60% by weight, preferably not more than 55% by weight. By setting the ratio of the hard segment within this range, the foam base material of the resin layer, especially the foam base material composed of a polyurethane foam or a polyolefin foam can be adhered to tightly. sexual enhancement.

Among them, from the viewpoint of improving the adhesion to the foam base material of the above-mentioned resin layer, especially a foam base material composed of a polyurethane foam or a polyolefin foam, a hard chain is further preferred. An acrylic triblock copolymer having a segment ratio of 10% by weight or more and 60% by weight or less. Using an acrylic triblock copolymer with excellent adhesiveness eliminates the need to use an adhesive or the like to make the resin layer adhere to the foam substrate, and the thickness of the obtained double-sided adhesive tape can be reduced.

Furthermore, the above-mentioned thermoplastic elastomer is also preferably composed of a triblock copolymer and a diblock copolymer (a triblock copolymer and a diblock copolymer) from the viewpoint of further improving stress relaxation properties, impact resistance, and reworkability. a mixture of block copolymers).

In a preferred embodiment of the present invention, the ratio 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, especially It is preferably at least 95% by weight, and may be 100% by weight.

The components constituting the hard segment of the acrylic triblock copolymer are not particularly limited, and include methyl methacrylate, ethyl methacrylate, n-butyl methacrylate, 2-methacrylate Ethylhexyl, lauryl methacrylate, alkyl methacrylate, tridecyl methacrylate, etc.

The components constituting the soft segment of the acrylic triblock copolymer are 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 preferred.

When the above-mentioned 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 triblock The preferable lower limit of the ratio of the methyl methacrylate-derived hard segment in a copolymer is 22 weight%. Moreover, a preferable upper limit is 50 weight%. Furthermore, the more preferable lower limit of the ratio of the hard segment derived from methyl methacrylate is 24% by weight, and the more preferable upper limit is 48% by weight. If the ratio of the hard segment derived from methyl methacrylate is within this range, particularly excellent adhesion to the foam base material can be exhibited, and the adhesion between the foam base material and the resin layer can be prevented. Protrusion etc. In addition, it exhibits excellent heat resistance and heat shrinkage resistance, for example, even when it is heat-treated at 100-200°C for about 10-30 minutes, it does not melt or cause wrinkles. Furthermore, when the rolled body is to be unfolded after being made into a roll, it will not fail to unfold due to adhesion.

When the above-mentioned 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 triblock The weight average molecular weight of the copolymer is preferably 30,000 or more. By setting the weight average molecular weight of the triblock copolymer to 30,000 or more, particularly excellent adhesion to the foam base material can be exhibited, and reworkability of the double-sided adhesive tape can be exhibited. The weight average molecular weight of the above-mentioned tri-block copolymer is more preferably 50,000 or more. The upper limit of the weight average molecular weight of the above-mentioned triblock copolymer is not particularly limited, but the upper limit is about 200,000 in consideration of handleability and the like.

The above-mentioned resin layer may also be colored. By coloring the said resin layer, light-shielding property can be provided to a double-sided adhesive tape.

The method of coloring the above-mentioned resin layer is not particularly limited, and examples thereof include: a method of kneading particles such as carbon black, titanium oxide, or fine air bubbles into the resin constituting the above-mentioned resin layer, and a method of coating ink on the surface of the above-mentioned resin layer. wait.

The above-mentioned resin layer may optionally contain conventionally known additives such as ultraviolet absorbers, antioxidants, organic fillers, and inorganic fillers. Moreover, when the resin which comprises at least one of the said 1st resin layer and the 2nd resin layer consists of a thermoplastic elastomer, resin other than the said thermoplastic elastomer may be contained as resin.

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

The double-sided adhesive tape according to one embodiment of the present invention may have layers other than the above-mentioned foam substrate, the above-mentioned adhesive agent layer, and the above-mentioned resin layer as needed.

The thickness of the double-sided adhesive tape according to an embodiment of the present invention is not particularly limited, but the lower limit is preferably 0.3 mm, and the upper limit is 3 mm. By setting the thickness of the double-sided adhesive tape according to an embodiment of the present invention within this range, it is possible to prevent the double-sided adhesive tape from being peeled off due to the inability to withstand the restoring force or the repulsive force, and it is possible to achieve sufficient bonding or fixation and excellent performance. reworkability. From the perspective of suppressing peeling of the double-sided tape and further improving reworkability, the thickness of the double-sided adhesive tape according to an embodiment of the present invention has a more preferable lower limit of 0.4 mm, and a more preferable upper limit of 2.8 mm.

As a manufacturing method of the double-sided adhesive tape of one embodiment of this invention, the following methods are mentioned, for example. First, a laminate of the above-mentioned foam base material and the first resin layer is produced, and the second resin layer is laminated on the laminate to form a laminate consisting of the first resin layer/foam base material/second resin layer. laminated body.

Here, in order to laminate the resin layer and the foam substrate, it is preferable that the resin layer has self-adhesiveness (adhesiveness). Moreover, adhesiveness can also be improved by pressure-bonding a resin layer and a foam base material with the laminating machine heated. Moreover, the adhesiveness can be further improved by inserting a resin layer at the time of the process of foaming a base material raw material and obtaining a foam base material. In addition, by performing surface treatment (such as plasma treatment or corona treatment) on the surface of the resin sheet used as the resin layer or the foam substrate, the adhesion between the resin layer and the foam substrate can also be improved. . Furthermore, when the resin layer has no self-adhesiveness, an adhesive layer may be provided and laminated between the foam base material and the resin layer. Adhesion between the resin layer and the foam substrate can also be improved by modifying the polymer chains of the resin layer with hydroxyl groups or acid groups serving as reaction points.

Next, prepare an adhesive solution for forming the above adhesive layer, apply the adhesive solution on the release-treated surface of the release film, and completely dry and remove the solvent in the solution to form the first adhesive layer. The first adhesive layer is superimposed on the first resin of the above-mentioned laminate composed of the first resin layer/foam base material/second resin layer in a state where the first adhesive layer and the first resin layer face each other. The surface of the layer side. On the other hand, prepare a release film different from the above-mentioned release film, apply an adhesive solution on the release treatment surface of the release film, and completely dry and remove the solvent in the solution, thereby making the release film The laminated film of the second adhesive layer is formed on the surface. Laminate the obtained laminated film on the second resin layer of the above-mentioned laminate consisting of the first resin layer/foam base material/second resin layer with the second adhesive layer facing the second resin layer side surface to obtain a laminate consisting of the first adhesive layer/first resin layer/foam substrate/second resin layer/second adhesive layer. Then, by pressing the obtained laminate with a rubber roller or the like, a first adhesive layer/first resin layer/foam base material/second resin layer/second adhesive layer can be obtained, and A double-sided adhesive tape with the surfaces of the two adhesive layers covered by a release film. Moreover, when winding up on a roll, the release film which was in contact with the 2nd adhesive layer was peeled off, and the 2nd adhesive layer was wound up inside. At this time, the release film in contact with the first adhesive layer needs to be subjected to double-sided release treatment.

The application of the double-sided adhesive tape according to an embodiment of the present invention is not particularly limited, for example, it can be used for fixing portable electronic device parts, vehicle-mounted electronic device parts, and the like. The shape of the double-sided adhesive tape according to an embodiment of the present invention in these applications is not particularly limited, and examples thereof include rectangular, frame-shaped, circular, elliptical, and ring-shaped.

The double-sided adhesive tape according to an embodiment of the present invention is excellent in adhesion reliability under a state where a peeling stress at a low speed such as a restoring force or a rebounding force is applied, so it is preferably attached to steps, corners, Non-planar parts, etc., or used to fix parts in a deformed state. On the other hand, because of its excellent reworkability, it can also be preferably used for temporary fixing purposes. Furthermore, when it is desired to peel off after bonding for some reason, the foam base material does not break at the time of peeling, and the adherend does not have a residue remaining.

As an article using the double-sided adhesive tape of an embodiment of the present invention, for example, flat panel displays used in TVs, monitors, portable electronic devices, camera modules of portable electronic devices, portable Internal components of electronic equipment, vehicle interiors, home appliances (such as TVs, air conditioners, refrigerators, etc.) interior and exterior decorations, etc. As an adherend of the double-sided adhesive tape according to an embodiment of the present invention, for example, side panels, rear panels, various nameplates, decorative films, decorative films, etc. of portable electronic devices can be mentioned.

According to the present invention, it is possible to provide a double-sided adhesive tape having excellent stress relaxation and impact resistance and excellent reworkability of both adhesive surfaces.

1‧‧‧Double-sided adhesive tape

2‧‧‧Foam base material

31‧‧‧The first adhesive layer

32‧‧‧The second adhesive layer

41‧‧‧The first resin layer

42‧‧‧The second resin layer

Fig. 1 is a schematic diagram showing an example of a double-sided adhesive tape according to an embodiment of the present invention.

Hereinafter, examples are given to describe aspects of the present invention in more detail, but the present invention is not limited to these examples.

(Example 1)

(1) Preparation of the first resin layer

As the first resin layer, a polyethylene terephthalate (PET) sheet (manufactured by Toray Corporation, X30) with a thickness of 50 μm was prepared. As a result of measuring by the method based on JIS K 7161, the tensile breaking point stress of the PET sheet was 180 MPa, the tensile breaking point elongation was 138%, and the tensile elastic modulus was 4360 MPa.

(2) Manufacture of polyurethane (PU) foam substrate

Add 0.7 parts by weight of amine catalyst (Dabco LV33, manufactured by Sankyo air-product company) in 100 parts by weight of polyol (polyether polyol, weight average molecular weight 6000, hydroxyl number 3, hydroxyl value 48mgKOH/g), and foam stabilization Agent (SZ5740M, manufactured by Toray Dow Corning Co.) 1 part by weight, and stirred. Polyisocyanate (COSMONATE TM-20, manufactured by Mitsui Chemicals Co., Ltd.) was put therein to adjust the isocyanate index to 80. Thereafter, it was mixed and stirred with nitrogen gas so as to be 0.2 g/cm ³ , and a solution in which fine air bubbles were mixed was obtained. Using an applicator, apply this solution to a specific thickness on the first resin layer, that is, on a polyethylene terephthalate (PET) sheet (manufactured by Toray Corporation, X30) with a thickness of 50 μm, and make the foam material The reaction was carried out to obtain a laminate composed of a polyurethane (PU) foam substrate and a first resin layer having a thickness of 450 μm.

The density of the obtained PU foam substrate was measured in accordance with JIS K-6767 using an electronic pycnometer (manufactured by MIRAGE, "ED120T"), and was 0.3 g/cm ³ . Furthermore, the 25% compressive strength of the obtained PU foam base material was calculated|required by measuring based on JISK6254, and it was 15 kPa.

(3) Preparation of the second resin layer

As the second resin layer, a sheet (manufactured by Kuraray, LA2250) made of acrylic triblock copolymer a (acrylic TPE-a) having a thickness of 50 μm was prepared.

Regarding this acrylic TPE-a, the ratio of the hard segment derived from polymethyl methacrylate resin is 30% by weight, the ratio of soft segment derived from polybutyl acrylate resin is 70% by weight, and the weight average molecular weight is 59000 .

As a result of the measurement based on JIS K 7161, the tensile breaking point stress of the sheet made of acrylic TPE-a was 8.0 MPa, the tensile breaking point elongation was 493%, and the tensile elastic modulus was 10.1 MPa.

(4) Preparation of adhesive solution

After adding 52 parts by weight of ethyl acetate to a reactor equipped with a thermometer, a stirrer, and a cooling pipe, and replacing it with nitrogen, the reactor was heated to start reflux. After boiling the ethyl acetate, 0.08 parts by weight of azobisisobutyronitrile as a polymerization initiator was added 30 minutes later. A mixture consisting of 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 slowly added dropwise thereto for 1 hour and 30 minutes. The monomer mixture for the reaction. 0.1 part by weight of azobisisobutyronitrile was added 30 minutes after the completion of the dropwise addition, and the polymerization reaction was carried out for 5 hours. While adding ethyl acetate in the reactor for dilution, cooling was performed to obtain a solid content of 40 parts by weight. % solution of acrylic acid copolymer.

The obtained acrylic acid copolymer was 710,000 when the weight average molecular weight was measured by GPC using "2690 Separations Model" manufactured by Water Co., Ltd. as a column. The ratio (Mw/Mn) of the weight average molecular weight (Mw) to the number average molecular weight (Mn) was 5.5.

To 100 parts by weight of the solid content of the obtained acrylic copolymer, 15 parts by weight of polymerized rosin ester with a softening point of 150°C, 10 parts by weight of terpene phenol with a softening point of 145°C, and 10 parts by weight of rosin ester with a softening point of 70°C were added . Furthermore, 30 parts by weight of ethyl acetate (manufactured by Fuji Chemical Co., Ltd.) and 3.0 parts by weight of an isocyanate-based crosslinking agent (manufactured by Nippon Polyurethane Co., Ltd., trade name "Coronate L45") were added and stirred to obtain an adhesive solution. .

(5) Manufacture of double-sided adhesive tape

Laminate a sheet made of acrylic triblock copolymer a as the second resin layer on the PU foam substrate side of the obtained laminate composed of the PU foam substrate and the first resin layer, and Thermal lamination was performed at 80° C. to form a laminate consisting of the first resin layer/foam substrate/second resin layer.

Apply the above-mentioned adhesive solution on the release surface of the release liner made of polyethylene (PE)/dowling paper/polyethylene (PE) with a thickness of 100 μm and dry at 100°C for 5 minutes, thereby forming a first adhesive layer with a thickness of 50 μm.

On the other hand, apply the above-mentioned adhesive solution to the mold release treatment surface of the mold release liner made of polyethylene (PE)/dolin paper/polyethylene (PE) that has been subjected to mold release treatment with a thickness of 100 μm. By drying at 100° C. for 5 minutes, a second adhesive layer with a thickness of 50 μm was formed.

Lay the release liner with the second adhesive layer on top of the first resin layer/foam substrate/second resin layer with the second adhesive layer facing the second resin layer. The surface of the laminate on the second resin layer side is obtained to obtain a laminate consisting of the first adhesive layer/first resin layer/foam substrate/second resin layer/second adhesive layer. Then, by pressing the obtained laminate with a rubber roller, a first adhesive layer/first resin layer/foam base material/second resin layer/second adhesive layer, and each A double-sided adhesive tape whose surface of the adhesive layer is covered by a release liner.

(Example 2)

As the second resin layer, a sheet made of acrylic triblock copolymer b (acrylic TPE-b) with a thickness of 50 μm (manufactured by Kuraray Co., Ltd., LA2140e) was used, and a double-sided film was produced in the same manner as in Example 1. Adhesive tape.

Regarding this acrylic TPE-b, the ratio of the hard segment derived from polymethylmethacrylate resin is 21% by weight, the ratio of soft segment derived from polybutylacrylate resin is 79% by weight, and the weight average molecular weight is 73000 .

As a result of measuring according to the method of JIS K 7161, the tensile breaking point stress of the sheet made of acrylic TPE-b was 5.0 MPa, the tensile breaking point elongation was 602%, and the tensile elastic modulus was 1.0 MPa.

(Example 3)

As the second resin layer, a sheet made of acrylic triblock copolymer c (acrylic TPE-c) with a thickness of 50 μm (manufactured by Kuraray Co., Ltd., LA2330) was used, and a double-sided film was produced in the same manner as in Example 1. Adhesive tape.

Regarding this acrylic TPE-c, the ratio of the hard segment derived from polymethyl methacrylate resin is 23% by weight, the ratio of soft segment derived from polybutyl acrylate resin is 77% by weight, and the weight average molecular weight is 112000 .

As a result of the measurement based on JIS K 7161, the tensile breaking point stress of the sheet made of acrylic TPE-c was 4.6 MPa, the tensile breaking point elongation was 550%, and the tensile elastic modulus was 0.6 MPa.

(Example 4)

As the second resin layer, a sheet made of acrylic triblock copolymer d (acrylic TPE-d) with a thickness of 50 μm (manufactured by Kuraray Co., Ltd., LA4285) was used, and a double-sided film was produced in the same manner as in Example 1 Adhesive tape.

Regarding this acrylic TPE-d, the ratio of the hard segment derived from polymethyl methacrylate resin is 55% by weight, the ratio of soft segment derived from polybutyl acrylate resin is 45% by weight, and the weight average molecular weight is 60000 .

As a result of the measurement based on JIS K 7161, the tensile breaking point stress of the sheet made of acrylic TPE-d was 18.1 MPa, the tensile breaking point elongation was 232%, and the tensile elastic modulus was 275.1 MPa.

(Example 5)

As the second resin layer, a sheet made of acrylic triblock copolymer e (acrylic TPE-e) with a thickness of 50 μm (manufactured by Kuraray Co., Ltd., LA2270) was used, and a double-sided film was produced in the same manner as in Example 1. Adhesive tape.

Regarding this acrylic TPE-e, the ratio of the hard segment derived from polymethyl methacrylate resin is 40% by weight, the ratio of soft segment derived from polybutyl acrylate resin is 60% by weight, and the weight average molecular weight is 60000 .

As a result of the measurement based on JIS K 7161, the tensile breaking point stress of the sheet made of acrylic TPE-e was 11.4 MPa, the tensile breaking point elongation was 434%, and the tensile elastic modulus was 51.8 MPa.

(Example 6)

As the second resin layer, an acrylic triblock copolymer e (acrylic TPE-e) (manufactured by Kuraray, LA2270) and an acrylic diblock copolymer f (acrylic TPE-f) (Kara A double-sided adhesive tape was produced in the same manner as in Example 1 except that the sheet constituted by a weight ratio of 85/15 (LA1114, manufactured by Lai Corporation).

Regarding this acrylic TPE-e, the ratio of the hard segment derived from polymethyl methacrylate resin is 40% by weight, the ratio of soft segment derived from polybutyl acrylate resin is 60% by weight, and the weight average molecular weight is 60000 .

As a result of measuring according to the method of JIS K 7161, the tensile breaking point stress of the sheet composed of acrylic TPE-e and acrylic TPE-f was 4.3 MPa, and the tensile breaking point elongation was 660%. The elastic modulus is 0.8MPa.

(Example 7)

A double-sided 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 this styrene/acrylic TPE, the ratio of the hard segment derived from the polystyrene resin was 17% by weight, the ratio of the soft segment derived from the polybutylacrylate resin was 83% by weight, and the weight average molecular weight was 240,000.

As a result of measuring according to the method of JIS K 7161, the tensile breaking point stress of the sheet made of styrene/acrylic TPE was 7.6MPa, the tensile breaking point elongation was 650%, and the tensile elastic modulus was 1.9MPa.

(Embodiment 8)

As the second resin layer, a sheet made of styrene-based triblock copolymer a (styrene TPE-a) with a thickness of 50 μm (manufactured by Nippon Zeon Co., Ltd., #3620) was used, except that it was the same as in Example 1. to manufacture double-sided adhesive tape.

In this styrene TPE-a, the ratio of the hard segment derived from styrene was 14 weight%, and the ratio of the soft segment derived from isoprene was 86 weight%. Also, in terms of GPC area ratio, 12% of diblock components of the same composition were included.

As a result of measuring according to the method of JIS K 7161, the tensile breaking point stress of the sheet made of styrene TPE-a was 24.0 MPa, the tensile breaking point elongation was 1200%, and the tensile elastic modulus was 40.0MPa.

(Example 9)

As the second resin layer, a sheet made of styrene-based triblock copolymer b (styrene TPE-b) with a thickness of 50 μm (manufactured by Nippon Zeon Co., Ltd., #3421) was used, except that it was the same as in Example 1. to manufacture double-sided adhesive tape.

In this styrene TPE-b, the ratio of the hard segment derived from styrene was 14 weight%, and the ratio of the soft segment derived from isoprene was 86 weight%. Also, in terms of GPC area ratio, 26% of diblock components of the same composition were included.

As a result of measuring according to the method of JIS K 7161, the tensile breaking point stress of the sheet made of styrene TPE-b was 19.0 MPa, the tensile breaking point elongation was 1300%, and the tensile elastic modulus was 38.0MPa.

(Example 10)

As the second resin layer, a sheet made of polyetherester-based block copolymer a (polyetherester TPE-a) (manufactured by Toray DuPont, #5557) having a thickness of 50 μm was used. A double-sided adhesive tape was produced in the same manner.

The polyether ester TPE-a has a hard segment derived from PBT and a soft segment derived from polyether.

As a result of measuring by the method based on JIS K 7161, the tensile breaking point stress of the sheet made of polyetherester TPE-a was 31.4MPa, the tensile breaking point elongation was 390%, and the tensile elastic modulus It is 137.0MPa.

(Example 11)

As the second resin layer, a sheet made of polyetherester-based block copolymer b (polyetherester TPE-b) (manufactured by Toray DuPont, #7247) with a thickness of 50 μm was used, and the same method as in Example 1 was used. A double-sided adhesive tape was produced in the same manner.

The polyether ester TPE-b has a hard segment derived from PBT and a soft segment derived from polyether.

Using the method based on JIS K 7161 to measure, the result is that the tensile breaking point stress of the sheet made of polyetherester TPE-b is 36.3MPa, the tensile breaking point elongation is 260%, and the tensile elastic modulus It is 422.0MPa.

(Example 12)

A double-sided adhesive tape was produced in the same manner as in Example 1 except that a sheet made of an urethane-based block copolymer (urethane TPE) with a thickness of 60 μm (BASF Corporation, 1198ATR) was used as the second resin layer.

As a result of the measurement based on JIS K 7161, the tensile breaking point stress of the sheet made of urethane TPE was 57.1 MPa, the tensile breaking point elongation was 406%, and the tensile elastic modulus was 108.0 MPa .

(Example 13)

As the second resin layer, a sheet made of biaxially stretched polypropylene (OPP) with a thickness of 60 μm (manufactured by Toyobo Co., Ltd., #60) was used, and the adhesive layer was passed through the lamination of the second resin layer and the foam base material. On the other hand, a double-sided adhesive tape was produced in the same manner as in Example 1 except for lamination.

As a result of the measurement based on JIS K 7161, the tensile breaking point stress of the OPP sheet was 140.0 MPa, the tensile breaking point elongation was 210%, and the tensile elastic modulus was 2100.0 MPa.

(Example 14)

As the second resin layer, a sheet made of polyethylene terephthalate (PET) with a thickness of 25 μm (manufactured by Toyobo Co., Ltd., #25) was used. A double-sided adhesive tape was produced in the same manner as in Example 1 except that the adhesive layer was laminated.

As a result of measuring by the method based on JIS K 7161, the tensile breaking point stress of the PET sheet was 177.0 MPa, the tensile breaking point elongation was 132%, and the tensile elastic modulus was 2376.0 MPa.

(comparative example 1)

As the second resin layer, a pulp nonwoven fabric sheet (manufactured by Lidong Shokai Co., Ltd., SPC) with a thickness of 50 μm was used, and when the second resin layer and the foam substrate were laminated, the adhesive layer was laminated. A double-sided adhesive tape was produced in the same manner as in Example 1.

As a result of measuring by a method based on JIS K 7161, the tensile breaking point stress of the pulp nonwoven fabric sheet was 3.7 MPa, the tensile breaking point elongation was 102%, and the tensile elastic modulus was 160.0 MPa.

(comparative example 2)

A double-sided adhesive tape was produced in the same manner as in Example 1 except that an acrylic adhesive with a thickness of 50 μm was used as the second resin layer.

As a result of the measurement based on JIS K 7161, the tensile breaking point stress of the layer made of acrylic adhesive was 0.5 MPa, the tensile breaking point elongation was 825%, and the tensile elastic modulus was 0.2 MPa .

Furthermore, the acrylic adhesive is prepared by the following method.

After adding 52 parts by weight of ethyl acetate to a reactor equipped with a thermometer, a stirrer, and a cooling pipe, and replacing it with nitrogen, the reactor was heated to start reflux. After boiling the ethyl acetate, 0.08 parts by weight of azobisisobutyronitrile as a polymerization initiator was added 30 minutes later. A monomer mixture (60 parts by weight of butyl acrylate (BA), 36.9 parts by weight of 2-ethylhexyl acrylate (2EHA), 3 parts by weight of acrylic acid (AAc), and 2-hydroxyethyl acrylate (2HEA) (0.1 parts by weight) for reaction. Add 0.1 part by weight of azobisisobutyronitrile 30 minutes after the end of the dropwise addition, and then carry out a polymerization reaction for 5 hours. While adding ethyl acetate in the reactor for dilution, cooling is carried out, whereby an acrylic acid copolymer is obtained. solution.

To 100 parts by weight of the nonvolatile matter of the obtained solution containing the acrylic acid copolymer, ethyl acetate was added and stirred, and a total of 30 parts by weight of tackifying resins (10 parts of hydrogenated rosin resin, 10 parts of rosin ester resin, terpene 10 parts of phenol resin) and stirred to obtain an adhesive with a non-volatile content of 30% by weight.

(comparative example 3)

As the second resin layer, a sheet made of acrylic diblock copolymer f (acrylic TPE-f) (manufactured by Kuraray, LA1114) having a thickness of 50 μm was used, and a double-sided film was produced in the same manner as in Example 1. Adhesive tape.

As a result of the measurement based on JIS K 7161, the tensile breaking point stress of the sheet made of acrylic TPE-f was 1.2 MPa, the tensile breaking point elongation was 990%, and the tensile elastic modulus was 0.3 MPa.

(evaluate)

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

(1) Evaluation of softness

The obtained double-sided adhesive tape (release liner/1st adhesive layer/1st resin layer/foam substrate/2nd resin layer/2nd adhesive layer) was made on the side of the 2nd adhesive layer The inner side is wound on a paper core with a diameter of 3 inches to obtain a roll.

The side surface and surface layer of the obtained rolled body were observed visually. Furthermore, after pulling out a double-sided adhesive tape from a roll, it observed visually from the 2nd adhesive layer side, and evaluated it based on the following reference|standard.

○: No creases or bends were observed in all the confirmed parts.

△: Wrinkles or bends are observed in one of the confirmed parts.

×: Wrinkles or bends are found in all the confirmed parts.

(2) Evaluation of reworkability

The obtained double-sided adhesive tape was cut into width 5 mm x length 100 mm, and width 10 mm x length 100 mm, respectively, to prepare 5 mm wide samples and 10 mm wide samples.

Peel off the release liner on the first adhesive layer side of each sample obtained, and attach the first adhesive layer side to a glass plate (width 50mm, length 125mm) with a thickness of 2mm, and make a 2kg rubber roller with a thickness of 300mm After going back and forth on the double-sided adhesive tape at a speed of /min, place it at 23°C and a relative humidity of 50% for 24 hours. Then, the interlayer of the foam substrate is torn apart, and after the second adhesive layer, the second resin layer, and part of the foam substrate are removed from the double-sided adhesive tape, the part of the double-sided adhesive tape remains Stretch at an angle of 30° from the horizontal direction at a speed of 300mm/min, and peel off the remaining double-sided adhesive tape from the glass plate. The reworkability on the side of the first adhesive layer was evaluated on the basis of the following criteria. The same evaluation was performed also about the 2nd adhesive layer side.

○: The portion where the double-sided adhesive tape remained was successfully removed.

△: A part of the double-sided adhesive tape was broken during peeling, but it could be removed.

×: The portion where the double-sided adhesive tape remained could not be removed.

[Table 1]

[Industrial availability]

According to the present invention, it is possible to provide a double-sided adhesive tape having excellent stress relaxation and impact resistance and excellent reworkability of both adhesive surfaces.

1‧‧‧Double-sided adhesive tape

2‧‧‧Foam base material

31‧‧‧The first adhesive layer

32‧‧‧The second adhesive layer

41‧‧‧The first resin layer

42‧‧‧The second resin layer

Claims (8)

A double-sided adhesive tape, which has a foam substrate, and a first adhesive layer and a second adhesive layer respectively located on both sides of the foam substrate, characterized in that: on the foam substrate Between the above-mentioned first adhesive layer and between the above-mentioned foam base material and the above-mentioned second adhesive layer, there are respectively a first resin layer and a second resin layer with a tensile fracture point stress of 4 MPa or more, and constitute the above-mentioned The resin of the first resin layer is polyester resin, the above-mentioned second resin layer is composed of thermoplastic elastomer, and the above-mentioned thermoplastic elastomer system is composed of a tri-block copolymer having a hard segment and a soft segment, or the above-mentioned tri-block copolymer It is composed of a mixture of compound and diblock copolymer. The double-sided adhesive tape according to claim 1, wherein the tensile elongation at break point of the second resin layer is 200% or more. The double-sided adhesive tape according to claim 1 or 2, wherein the tensile elastic modulus of the second resin layer is 200 MPa or less. The double-sided adhesive tape according to claim 1 or 2, wherein the ratio of the hard segment in the block copolymer is 10% by weight or more and 70% by weight or less. The double-sided adhesive tape according to claim 1 or 2, wherein the ratio of the triblock copolymer in the second resin layer is 70% by weight or more. The double-sided adhesive tape according to claim 1 or 2, wherein the second resin layer is made of acrylic copolymer. The double-sided adhesive tape according to claim 1 or 2, wherein the triblock copolymer is an acrylic triblock copolymer, and the acrylic triblock copolymer has a hard segment derived from methyl methacrylate , and the soft segment derived from n-butyl acrylate, the ratio of the hard segment derived from methyl methacrylate in the above-mentioned acrylic triblock copolymer is 22% by weight or more and 50% by weight or less, and the above-mentioned The weight average molecular weight of the acrylic triblock copolymer is more than 30,000. The double-sided adhesive tape according to claim 1 or 2, wherein the foam substrate is made of polyurethane foam or polyolefin foam.

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