JP2021102699A - Pressure sensitive adhesive tape - Google Patents

Abstract

To provide a pressure sensitive adhesive tape capable of avoiding air bubbles between the pressure sensitive adhesive tape and an adherend when sticking the pressure sensitive adhesive tape and peeling the pressure sensitive adhesive tape without damaging a display.SOLUTION: A pressure sensitive adhesive tape includes a resin layer (B) on at least one surface of a foam layer (A) and two or more adhesion parts (C) on the side of a surface (a) opposite to the foam layer of the resin layer (B). A region without having the adhesion parts (C) exists between the two or more adhesion parts (C); the region leads to an end portion of the pressure sensitive adhesive tape; the elongation of the pressure sensitive adhesive tape at a breaking point is 500-3000%; and the stress thereof at the breaking point is 3.0-30.0 MPa.SELECTED DRAWING: Figure 1

Description

The present invention relates to an adhesive tape having a foam layer that can be used in the manufacturing scene of, for example, an electronic device.

Adhesive tapes are widely used in the manufacturing of electronic devices such as OA devices and home appliances because of their excellent workability and high adhesive reliability.
In recent years, electronic devices, especially personal computers, digital video cameras, electronic organizers, mobile phones, PHS, smartphones, game devices, electronic books, and other portable electronic terminals have been required to be smaller and thinner. The adhesive tape and the like constituting the portable electronic terminal are also required to be thin.

In general, the above-mentioned display devices often have an adhesive tape having a cushioning foam layer attached to the back surface of the display for the purpose of preventing the display from cracking or pooling (the phenomenon of waviness of light and shade of the liquid crystal). Patent Document 1).

However, since the adhesive tape having the foamed layer is very flexible, air bubbles are often caught in the adhesive tape at the time of sticking and wrinkles are formed. In particular, the above-mentioned problems have been remarkably generated when laminating several minutes after aligning the positions with a press machine at the time of sticking.

In addition, when a problem is confirmed due to foreign matter being caught in the display after bonding, there is a problem that the display is damaged especially when the adhesive tape is tried to be peeled off from the fragile display.

Japanese Unexamined Patent Publication No. 2004-309699

An object of the present invention to be solved is to provide an adhesive tape that can be peeled off without damaging the display while preventing air bubbles from remaining between the adhesive tape and the adherend when the adhesive tape is attached. And.

The present inventors have a resin layer (B) on at least one surface of the foam layer (A), and the resin layer (B) is on the surface (a) opposite to the foam layer (A). An adhesive tape having two or more adhesive portions (C), and a region having no adhesive portion (C) exists between the two or more adhesive portions (C), and the region is the end of the adhesive tape. The above-mentioned problem is solved by the adhesive tape which is familiar to the part, has a breaking point elongation of 500 to 3000%, and has a breaking point stress of 3.0 to 30.0 MPa. Settled.

Further, according to the present invention, it is possible to solve the above problems and maintain the airtightness between the adhesive tape and the adherend, and to fill the voids formed between the adhesive tape and the adherend. It can prevent the intrusion of moisture. In this respect, in the present invention, the above-mentioned adhesive portion (C) is provided to maintain a path for achieving bubble removal between the adhesive tape and the adherend, and the adhesive is attached by such a bubble removal path or the like. A gap will be provided between the adhesive tape and the adherend later, which may cause a secondary problem that moisture invades the gap from the outside. This problem becomes a problem when an adhesive tape is applied to the back surface (attached surface) of a display, for example, in an organic EL display as a display element, because moisture invades the back surface of the display, causing defects. With respect to such a problem, according to the adhesive tape of the present invention, by applying a resin layer (B) having an appropriate adhesive force between the foam layer (A) and the adhesive portion (C), the adhesive can be adhered. The airtightness between the tape and the adherend can be improved, and the invasion of moisture through the air bubble escape path can be prevented. This is because when the resin layer (B) having an appropriate adhesive force is applied, the resin layer (B) becomes familiar with the adhesive portion (C) after the adhesive tape is attached, and the adhesive tape and the adherend are separated from each other. It is considered that the voids are also appropriately filled.

The adhesive tape of the present invention prevents air bubbles from remaining between the adhesive tape and the adherend at the time of sticking, does not require the adhesive tape to be embrittled by heat or an organic solvent, and is placed on the adherend. There is no residue such as adhesive, and it can be peeled off cleanly by stretching it in the horizontal direction, and the adherend can be reused. Therefore, the adhesive tape of the present invention can prevent cracking and pooling of the display without lowering the production efficiency of the final product and its parts. Therefore, the adhesive tape of the present invention can be suitably used, for example, for adhering to the non-display surface side of a display of a display device.

Further, according to the adhesive tape of the present invention, it is possible to maintain the airtightness between the adhesive tape and the adherend while preventing the residual air bubbles between the adherend and the adherend at the time of sticking, and the adherence can be maintained. It is possible to prevent the invasion of moisture into the voids generated between the body and the body. Therefore, it is particularly suitable for use in applications where airtightness with an adherend is required, such as sticking to the back surface of a display such as an organic EL display.

It is a top view of the adhesive tape having a substantially rhombus-shaped adhesive portion as viewed from the adhesive portion side. It is a top view of the adhesive tape having a substantially circular adhesive portion as viewed from the adhesive portion side. It is a top view of the adhesive tape having a substantially hexagonal adhesive portion as viewed from the adhesive portion side. It is a top view of the adhesive tape having a substantially square-shaped adhesive portion as viewed from the adhesive portion side. It is a top view observation photograph of manufacturing an adhesive tape having a substantially circular adhesive portion and seeing from the adhesive portion side.

(Adhesive tape)
An adhesive tape having two or more adhesive portions (C) on the surface (a) side of the foam layer (A), the resin layer (B), and the resin layer (B) opposite to the foam layer (A). There is a region having no adhesive portion (C) between the two or more adhesive portions (C), the region is connected to the end portion of the adhesive tape, and the elongation at break is high. It is 500 to 3000%, and the breaking point stress is 3.0 to 30.0 MPa.

As a specific embodiment of the adhesive tape of the present invention, 2 on the surface (a) side of the foam layer (A), the resin layer (B), and the resin layer (B) opposite to the foam layer (A). Examples thereof include a single-sided adhesive tape having the above-mentioned adhesive portion (C) and a double-sided adhesive tape having an adhesive layer (E) on the foam layer (A) side as well. Further, an intermediate layer such as a metal foil layer may be provided between the pressure-sensitive adhesive layer (E) and the foam layer (A).

Between the two or more adhesive portions (C), there is a region in which the component constituting the adhesive portion (C) does not exist or may exist to such an extent that the adhesiveness is not exhibited. Therefore, when the adhesive tape of the present invention is observed from the side surface direction, it is observed that the adhesive portion (C) forms a convex shape with respect to the resin layer (B) surface.

Further, the adhesive tape of the present invention has a structure in which a region having no adhesive portion (C) between the two or more adhesive portions (C) is connected to a part of an end portion (outer edge portion) of the adhesive tape. .. By using the adhesive tape having the above structure, when the adhesive tape is attached to the adherend, air bubbles escape from the interface between the adhesive tape and the adherend to the outside through the region, so that the adhesive tape swells or the like. It is possible to prevent poor appearance due to the above, and to maintain excellent cushioning properties and adhesive strength.

The elongation at break of the adhesive tape is 500 to 3000%, preferably 650 to 2800%, more preferably 700 to 2700%, and even more preferably 750 to 2600%. Within the breaking point elongation range, even when the adhesive tape is firmly adhered to the adherend, it can be peeled off with an appropriate tensile stress, and the adhesive tape is excessively stretched even in the peeling step. It can be easily peeled off without being too much.

The breaking point stress of the adhesive tape is 3.0 to 30.0 MPa, preferably 4.0 to 20.0 MPa, and more preferably 5.0 to 15.0 MPa. Since the breaking point stress of the adhesive tape is within the above range, the adhesive tape is not torn even when the adhesive tape is stretched and peeled off, and the adhesive tape is easily stretched favorably, so that the peeling work can be performed by peeling. It will be easier. In addition, the force required to stretch and deform the adhesive tape also depends on the thickness of the adhesive tape. For example, when an adhesive tape having a large thickness and a high breaking point stress is stretched and attempted to be peeled off, it cannot be stretched sufficiently and cannot be peeled off again.

As the adhesive tape of the present invention, it is preferable to use a tape having a total thickness of 300 μm or less, more preferably 50 μm to 275 μm, and further preferably 75 μm to 250 μm. It is particularly preferable to use one having a size of 50 μm to 200 μm in order to contribute to thinning of, for example, a portable electronic terminal. The total thickness of the adhesive tape was measured according to JIS K6250 by a method using a dial gauge under the conditions that the contact surface of the dial gauge was flat, the diameter was 8 mm, and the load was 0.51 N. It refers to the thickness of the release liner and does not include the thickness of the release liner. The thickness can be measured with, for example, a thickness gauge FFG-6 manufactured by Ozaki Seisakusho.

As the adhesive tape of the present invention, it is preferable to use one having an adhesive strength of 3N / 25mm to 40N / 25mm, and more preferably to use one having an adhesive strength of 5N / 25mm to 30N / 25mm, 7N. Using an adhesive with an adhesive strength of / 25 mm to 20 N / 25 mm removes air bubbles from the interface between the adherend and the adhesive tape even when it is thin and there are no holes or the like. It is preferable to obtain an adhesive tape that is easy to be used and has excellent adhesive strength.

The adhesive strength refers to a value measured according to JISZ0237. Specifically, the adhesive force is such that the surface of the adhesive tape having the adhesive portion (C) and a clean and smooth stainless steel plate (BA plate) are overlapped, and the upper surface thereof is reciprocated once using a 2 kg roller. It is a value measured by peeling off the adhesive tape at a speed of 0.3 m / min in the 180 ° direction after allowing the product pressurized with the above pressure to stand for 1 hour under the conditions of 23 ° C. and 50% RH.

Even if the adhesive tape of the present invention is thin, it can prevent peeling over time and parts falling off due to the repulsive force of the adherend and the foam layer (A), and is particularly used at a relatively high temperature. Even in the case of this, in order to prevent the peeling and the like, it is preferable to use one having a holding force of 2 mm or less, more preferably one having a holding force of 0.5 mm or less, and 0.1 mm or less. It is more preferable to use the one that is.

The holding force refers to a value measured according to JISZ0237. Specifically, the holding force is applied by superimposing the surface of the adhesive tape having the adhesive portion (C) and a clean and smooth stainless steel plate (hairline), and reciprocating once on the upper surface of the surface using a 2 kg roller. The pressed product is left to stand for 1 hour under the conditions of 23 ° C. and 50% RH, and used as a test piece. Next, the stainless steel plate constituting the test piece was vertically fixed in an environment of 100 ° C., and the test piece was left to stand for 24 hours with a load of 100 g applied to the lower end of the adhesive tape constituting the test piece. It is a value obtained by measuring the deviation distance between the stainless steel plate and the adhesive tape with a caliper.

(Effervescent layer (A))
The thickness of the foam layer (A) constituting the adhesive tape of the present invention is not particularly limited, but is preferably 250 μm or less, more preferably 30 μm to 200 μm, and further preferably 50 μm to 150 μm. Can be used. The adhesive tape can be made thinner by using the foam layer (A) having a thickness in the above range. Further, even when a hole or the like is not provided in a part of the adhesive tape, air bubbles can be easily removed from the interface between the surface having the adhesive portion (C) and the adherend, and as a result, the above-mentioned It is more preferable because it can more effectively prevent poor appearance due to swelling of the adhesive tape and performance deterioration such as cushioning property and adhesive strength.

As the foam layer (A), those having a 25% compressive strength of 0.01 MPa to 1 MPa are preferably used, and those having a 25% compressive strength of 0.03 MPa to 0.5 MPa are more preferably used. It is more preferable to use one having a value of 05 MPa to 0.4 MPa. It is particularly preferable to use an adhesive tape in the above range in order to obtain an adhesive tape having cushioning properties and suitable followability to an adherend.

As the foam layer (A), for example, a sheet-like material made of foamed resin can be used.

Examples of the foam layer (A) include polyolefin-based foams including polyethylene, polypropylene, ethylene-propylene copolymer, ethylene-vinyl acetate copolymer, polyurethane-based foams, acrylic rubber, and other elastomers. A rubber-based foam containing the above can be used. Among them, the foam layer (A) is particularly preferably polyurethane-based or acrylic-based, which easily forms a thin and flexible foam layer.

The polyurethane foam layer mixes a raw material containing polyisocyanate and polyol with a gas to generate a gas-liquid mixture, supplies the obtained gas-liquid mixture onto a pressure-sensitive adhesive, and then prepares the gas-liquid mixture. It is obtained by heating and reacting the raw materials.

The raw material of the polyurethane foam layer is a composition containing polyisocyanate and a polyol, and if necessary, contains the following other components.
The polyisocyanate is not particularly limited, and a polyisocyanate conventionally used for producing a polyurethane foam can be used. As this polyisocyanate, 4,4'-diphenylmethane diisocyanate, tolylene diisocyanate and the like are usually used. In addition to these, 1,6-hexamethylene diisocyanate, 1,5-naphthalenediocyanate, paraphenylenediocyanate, 2,2,4-trimethylhexamethylene diisocyanate, 4,4'-dicyclohexylmethane diisocyanate, hexamethylene diisocyanate, isophorone diisocyanate Aromatic or aliphatic polyisocyanates such as, prepolymer type polyisocyanates and the like can also be used. The polyisocyanate may be used in combination of two or more types, or may be used alone.
The polyisocyanate is blended so that the isocyanate index is preferably 0.8 to 1.2, particularly preferably 0.9 to 1.1.

The above-mentioned polyol is not particularly limited, and a polyol conventionally used for producing a polyurethane foam can be used. Specifically, a polyether polyol, a polyester polyol, a polyether ester polyol which is a copolymer of a polyether polyol and a polyester polyol, and the like can be used. Further, in order to improve the tensile strength, a polymer polyol can also be used in combination. As the polymer polyol, for example, an ethylenically unsaturated compound such as acrylonitrile, styrene, or methyl methacrylate is added to the polyether polyol, preferably 5 to 40% by mass, more preferably 10 to 30% by mass in terms of solid content, and kraft polymerization. It is a polymerized polyol.

The average molecular weight of the polyol is preferably 300 to 6000, more preferably 900 to 4000. One type of the polyol may be used, or two or more types may be used in combination.

As a raw material for the polyurethane foam layer other than the above, a catalyst, a defoaming agent, a cross-linking agent and the like are contained.

Examples of the catalyst include organic tin compounds such as stanas octoate, dibutyltin diacetate and dibutyltin dilaurate, organic zinc compounds such as zinc octylate, organic nickel compounds such as nickel acetylacetoate and nickel diacetylacetoate, and iron acetylacetoate. Organic iron compounds such as, alkali metal or alkaline earth metal alkoxides such as sodium acetate, metal catalysts such as phenoxide, tertiary amine-based catalysts such as triethylamine, triethylenediamine, N-methylmorpholine dimethylaminomethylphenol, and imidazole, organic Examples include acid salts. Of these, organotin compounds are particularly preferred. One type of the catalyst may be used, or two or more types may be used in combination.
The content of the catalyst is preferably 0.03 to 3.0 parts by mass when the polyol is 100 parts by mass. Particularly preferably, it is 0.05 to 2.0 parts by mass.

As the defoaming agent, a silicone-based defoaming agent is used. As the silicone-based defoaming agent, a dimethylsiloxane-based compound, a polyetherdimethylsiloxane-based compound, a phenylmethylsiloxane-based compound, or the like can be used. One type of the above-mentioned foam stabilizer may be used, or two or more types may be used in combination.
The content of the defoaming agent is preferably 1 to 20 parts by mass when the polyol is 100 parts by mass. Particularly preferably, it is 2 to 10 parts by mass.

As the cross-linking agent, ethylene glycol, trimethylolpropane or the like is used as an initiator, an ester-based oligomer chain-extended with ε-caplacton, a cross-linking agent having a large molecular weight such as a trifunctional polyether polyol having a molecular weight of about 300 to 700, or ethylene glycol. , Diethylene glycol, glycerin, trimethylolpropane and other short chain diol-based cross-linking agents. By using a high molecular weight cross-linking agent, a more flexible foam layer (A) can be obtained. One type of cross-linking agent may be used, or two or more types may be used in combination.
The content of the cross-linking agent contained in the raw material of the polyurethane-based foam layer depends on the type thereof, but when the polyol is 100 parts by mass, it is preferably 1 to 10 parts by mass, particularly preferably 2 to 5 parts by mass. It is a department.

Additives such as an ultraviolet absorber, an antioxidant, an organic and inorganic filler, and a colorant can be added to the foam raw material, if necessary.

(Resin layer (B))

The stress of the resin layer (B) at 100% elongation is preferably 0.3 to 3.0 MPa, more preferably 0.4 to 2.0 MPa, and 0.5 to 1.5 MPa. Is even more preferable. When the stress at 100% elongation of the adhesive tape is within the above range, the adhesive strength suitable for the adhesive tape can be obtained, and the adhesive tape can be peeled off relatively easily even in the step of re-peeling. If it is less than the above range, there is a concern that the adhesive tape may be peeled off when a load is applied to the adhesive tape in the shearing direction while fixing the hard adherends to each other. On the other hand, if it exceeds the above range, the force required to stretch the adhesive tape becomes excessive in the process of peeling the adhesive tape.

The storage elastic modulus G'of the resin layer (B) at 60 ° C. is preferably 0.2 MPa to 2.0 MPa, more preferably 0.3 MPa to 1.5 MPa, and 0.4 MPa to 1.0 MPa. Is more preferable. When the storage elastic modulus G'of the resin layer (B) is within the above range, it is possible to prevent the resin layer from becoming the same as the adhesive portion (C) and disappearing between the adhesive portion and the region having no adhesive portion. As a result, the shape of the adhesive portion (C) can be maintained, and air bleeding property after long-term storage can be ensured.

The elongation at break point of the resin layer (B) is preferably 500 to 3000%, more preferably 600 to 2800%, further preferably 700 to 2500%, and 750 to 2000%. Is even more preferable. When the breaking point elongation of the resin layer (B) is equal to or higher than the lower limit of the above range, even when the adhesive tape is firmly adhered to the adherend, the adhesive tape is peeled off in the horizontal direction of the tape. The stress for stretching does not become too large, and the adhesive tape can be easily peeled off without being excessively stretched even in the peeling step. Further, when the elongation at the breaking point of the resin layer (B) is equal to or less than the upper limit of the above range, the tape can be stretched in the horizontal direction when the adhesive tape is peeled off again, and the work can be performed in a small space. Therefore, it is preferable.

The breaking point stress of the resin layer (B) is preferably 3.0 to 30.0 MPa, more preferably 4.0 to 25.0 MPa, and further preferably 5.0 to 20.0 MPa. preferable. When the breaking point stress of the resin layer (B) is within the above range, it is possible to prevent the adhesive tape from being torn even when the adhesive tape is stretched and peeled off, and the load for stretching the adhesive tape is excessive. Since it does not become too much, the re-peeling work by peeling becomes easy. In addition, the force required to stretch and deform the adhesive tape also depends on the thickness of the adhesive tape. For example, when an adhesive tape having a large thickness and a high breaking point stress is stretched and attempted to be peeled off, it cannot be stretched sufficiently and cannot be peeled off again.

The thickness of the resin layer (B) is preferably 10 to 200 μm, more preferably 20 to 150 μm, and even more preferably 30 to 100 μm. When the thickness of the base material is within the above range, the adhesive tape can easily follow the strain of the adherend and obtain high adhesive strength, and the stress required for re-peeling the adhesive tape while stretching it in the horizontal direction. Is preferable because it does not become too large.

Further, the thickness of the resin layer (B) is preferably thicker than the thickness of the adhesive portion (C) described later. The thickness of the resin layer (B) is preferably such that the ratio of the thickness of the adhesive portion (C) to the thickness of the adhesive portion (B) (thickness of the resin layer (B) / thickness of the adhesive portion (C)) is 5 to 15, preferably 7 to 13. More preferably. Within the above range, it is possible to achieve both the ease of removing air bubbles when the adhesive tape is attached to the adherend and the improvement of the airtightness between the adhesive tape and the adherend.

The adhesive strength of the resin layer (B) of the adhesive tape of the present invention is preferably 0.5N / 25mm to 30N / 25mm, more preferably 1N / 25mm to 25N / 25mm, and 2N / 25mm to 20N. It is more preferably / 25 mm. When the adhesive force of the resin layer (B) of the present invention is within the above range, the airtightness between the adhesive tape and the adherend can be enhanced, and the invasion of moisture through the air bubble escape path can be prevented. Become.

The adhesive strength refers to a value measured according to JISZ0237. Specifically, the adhesive force is such that the surface of the adhesive tape having the adhesive portion (C) and a clean and smooth stainless steel plate (BA plate) are overlapped, and the upper surface thereof is reciprocated once using a 2 kg roller. It is a value measured by peeling off the adhesive tape at a speed of 0.3 m / min in the 180 ° direction after allowing the product pressurized with the above pressure to stand for 1 hour under the conditions of 23 ° C. and 50% RH.

The resin layer (B) of the adhesive tape of the present invention preferably contains a vinyl aromatic block copolymer or an acrylic block copolymer. When the resin layer (B) contains a vinyl aromatic block copolymer, it is preferable that the resin layer (B) contains a tackifier resin.

As the vinyl aromatic block copolymer, a block copolymer of an aromatic vinyl compound and a conjugated diene compound can be used, and a styrene-based copolymer in which the aromatic vinyl compound is styrene is preferable. Further, as the conjugated diene compound, isoprene, butadiene, ethylene butylene and ethylene propylene are preferable. Among them, the block copolymers include styrene-isoprene copolymers, styrene-butadiene copolymers, styrene-ethylenebutylene copolymers, diblock copolymers such as styrene-ethylenepropylene copolymers, and styrene-. One or more copolymers selected from triblock copolymers such as isoprene-styrene copolymer and styrene-butadiene-styrene copolymer are preferable, and styrene-isoprene copolymer and styrene-butadiene copolymer weight are preferable. One or more copolymers selected from coalescence, styrene-ethylenebutylene copolymer, styrene-isoprene-styrene copolymer, styrene-butadiene-styrene copolymer, styrene-ethylenebutylene copolymer Styrene-isoprene copolymer and styrene-isoprene-styrene copolymer are particularly preferable.

The proportion of the vinyl aromatic block copolymer in the resin component contained in the resin layer (B) of the present invention is preferably 50 to 100%, more preferably 60 to 100%, and 65 to 100%. It is even more preferably%, and even more preferably 70 to 100%. Within this range, excellent breaking point elongation and breaking point stress possessed by the styrene-based copolymer can be obtained. Further, various thermoplastic resins such as polyolefin and polycarbonate can be used as other than the vinyl aromatic block copolymer contained in the base material of the present invention, and one or more kinds can be used at the same time.

The styrene-based copolymer contains 13% by mass to 60% by mass of the structural unit represented by the following chemical formula (1) with respect to the total mass of the styrene-isoprene copolymer and the styrene-isoprene-styrene copolymer. It is preferable to use the one having in the range of 15 to 50% by mass, more preferably to use the one having in the range of 16 to 45% by mass, and further preferably to use the one having in the range of 16 to 45% by mass. It is even more preferable to use one having a mass in the range of%. As a result, it becomes easy to obtain a resin layer having a breaking point elongation and a breaking point stress in a suitable range.

As the styrene-based copolymer, one containing two or more kinds of copolymers having different structures is used, and one containing a combination of a styrene-isoprene copolymer and a styrene-isoprene-styrene copolymer is used. Can be done.
The styrene-based copolymer contains the styrene-isoprene copolymer in the range of 0% by mass to 80% by mass with respect to the total mass of the styrene-isoprene copolymer and the styrene-isoprene-styrene copolymer. It is preferable to use one containing styrene, more preferably one containing in the range of 0% by mass to 70% by mass, and further preferably using one containing in the range of 0% by mass to 50% by mass. , It is more preferable to use it in the range of 0% by mass to 30% by mass. Within the above range, it is possible to achieve both thermal durability while maintaining excellent breaking point elongation and breaking point stress.

Further, as the styrene-isoprene copolymer, the weight average molecular weight (gel permeation chromatography, SC-8020 manufactured by Toso Co., Ltd., high molecular weight column TSKgelGMHR) measured in terms of standard polystyrene using a gel permeation chromatograph (GPC). -H, solvent: tetrahydrofuran) is preferably in the range of 10,000 to 800,000, more preferably in the range of 30,000 to 500,000, and in the range of 50,000 to 300,000. It is even more preferable to use one that is. Within the above range, heat fluidity and compatibility at the time of solvent dilution can be ensured, so that an adhesive tape having good workability in the manufacturing process and thermal durability can be obtained.

As the styrene-based copolymer, for example, one having a single structure such as a linear structure, a branched structure or a multi-branched structure can be used, but those having different structures can also be mixed and used. .. The styrene-based copolymer rich in linear structure gives the adhesive tape of the present invention excellent breaking point elongation. On the other hand, a branched structure or a multi-branched structure in which a styrene block is arranged at the molecular end can have a pseudo-crosslinked structure and can provide excellent cohesive force. Therefore, it is preferable to mix and use according to the required mechanical characteristics.

The method for producing the styrene-isoprene-styrene copolymer is not particularly limited, and conventionally known production methods can be applied. For example, a method of sequentially polymerizing a styrene block and an isoprene block by an anion-living polymerization method, or a block copolymer having a living active terminal and then reacting with a coupling agent to produce a coupled block copolymer is produced. There is a way.

The method for producing the styrene-isoprene copolymer is not particularly limited, and conventionally known production methods can be applied. For example, there is a method in which a styrene block and an isoprene block are sequentially polymerized by an anion living polymerization method.

The method for producing the mixture of the styrene-isoprene copolymer and the styrene-isoprene-styrene copolymer is not particularly limited, and conventionally known production methods can be applied. For example, there is a method in which the styrene-isoprene copolymer produced above and the styrene-isoprene-styrene copolymer are mixed and used. It is also possible to produce a mixture at the same time in one polymerization step. As a more specific embodiment, a polystyrene block having a living active terminal is firstly polymerized by an anionic living polymerization method using an anionic polymerization initiator in a polymerization solvent. To form. Secondly, isoprene is polymerized from the living-active terminal of the polystyrene block to obtain a styrene-isoprene block copolymer having a living-active terminal. Subsequently, thirdly, a part of the styrene-isoprene block copolymer having the living active terminal is reacted with the coupling agent to form a coupled styrene-isoprene-styrene block copolymer. Fourth, the rest of the styrene-isoprene block copolymer having a living active end is deactivated with a polymerization inhibitor to deactivate the living active end to form a styrene-isoprene block copolymer. To form.

Next, as the acrylic block copolymer, one kind or two or more kinds of copolymers selected from block copolymers of polymethyl methacrylate and acrylic acid ester can be used. Further, as the acrylic acid ester, butyl acrylate and 2-ethylhexyl acrylate are preferable. Among them, the block copolymers include polymethylmethacrylate-butylpolyacrylate-polymethylmethacrylate copolymer and polymethylmethacrylate-polyacrylate 2-ethylhexyl-polymethylmethacrylate copolymer copolymer. One or more copolymers selected from the triblock copolymers such as, etc. are preferable.

The proportion of the acrylic block copolymer in the resin component contained in the resin layer (B) of the present invention is preferably 50 to 100%, more preferably 60 to 100%, and 65 to 100%. It is even more preferably, and even more preferably 70 to 100%. Within this range, excellent breaking point elongation and breaking point stress possessed by the polymethyl methacrylate copolymer can be obtained.

As the polymethacrylic acid copolymer, one having a content in the range of 10% by mass to 30% by mass with respect to the total mass of the polymethylmethacrylate-butylpolyacrylate-polymethylmethacrylate copolymer is used. It is preferable to use the one having a range of 12 to 27% by mass, and further preferably to use the one having a range of 15 to 25% by mass. As a result, the elongation at the breaking point and the stress at the breaking point can be easily obtained in a suitable range.

Further, the resin layer (B) may contain a tackifier resin for the purpose of enhancing the adhesiveness with the adhesive portion (C) and enhancing the heat resistance. The application of the tackifier resin is preferable because it is possible to obtain an adhesive tape that easily maintains the airtightness between the adhesive tape and the adherend, especially when the resin layer (B) contains a vinyl aromatic block copolymer. , It is preferable to apply a tackifier resin. When the tackifier resin is applied, it is considered that the resin layer (B) becomes more suitable for the adhesive portion (C) after the adhesive tape is attached, so that the airtightness can be easily maintained. In particular, when the resin layer (B) contains a vinyl aromatic block copolymer, it is preferable to contain a tackifier resin in order to impart adhesiveness. Among them, a tackifier resin having a softening point of 80 ° C. or higher can be preferably used, and the softening point is more preferably 90 ° C. or higher, further preferably 100 ° C. or higher, and even more preferably 110 ° C. or higher. preferable. The softening point refers to a value measured by a method (dry-bulb type) specified in JIS K2207.

As the tackifying resins, for example, preferably used ones at ordinary temperature (23 ° C.) solid, C ₅ petroleum resins, C ₅ based / C ₉ petroleum resins, petroleum such as alicyclic petroleum resin Resin can be used.
The petroleum resin is easily compatible with the polyisoprene structure constituting the styrene-isoprene block copolymer or the styrene-isoprene block-styrene copolymer, and as a result, the initial adhesive strength and thermal durability of the adhesive tape are improved. It can be further improved.
Examples of the _{C 5} petroleum resins, can be used aliphatic petroleum resin, for example, Escorez 1202,1304,1401 (Tonen Ltd. LLC), Wing Tack 95 (Goodyear Tire & Rubber Company , Quinton K100, R100, F100 (manufactured by Nippon Zeon Co., Ltd.), Pico Tack 95, Pico Pale 100 (manufactured by Rika Hercules) and the like can be used.

Examples of the _{C 5} system / _{C 9} petroleum resins, and _{C 5} petroleum resins described above, can be used a copolymer of _{C 9} petroleum resins, for example, Escorez 2101 (manufactured by Tonex), Quinton G115 (Nippon Zeon), Harcotac 1149 (Rika Hercules), etc. can be used.
As the alicyclic petroleum resin, it is obtained by hydrogenating the above-mentioned _{C 9} petroleum resins, for example, Escorez 5300 (manufactured by Tonex), ARKON P-100 (manufactured by Arakawa Chemical Industries), Rigaraito R101 (Rika Fine Tech) etc. can be used.

As the tackifier resin, the C ₅ petroleum resins, C ₅ based / C ₉ petroleum resins, and in addition alicyclic petroleum resin, for example, polymerized rosin-based resins, C ₉ petroleum resins, terpene resins , Rosin-based resin, terpene-phenol resin, styrene resin, kumaron-inden resin, xylene resin, phenol resin and the like can be used.
Among them, as the tackifier resin, the combined use of said C ₅ petroleum resins and polymerized rosin resin, preferable for both the more excellent initial adhesion and heat resistance.

The tackifier resin is preferably used in the range of 0% by mass to 100% by mass, and 0% by mass to 70% by mass, based on the total amount of the styrene-isoprene copolymer and the styrene-isoprene-styrene copolymer. It is more preferable to use it in the range of 0% by mass to 50% by mass, and even more preferably it is used in the range of 0% by mass to 30% by mass. By using it in the above range, it becomes easy to achieve both excellent breaking point elongation and thermal durability of the adhesive tape while enhancing the interfacial adhesion between the resin layer and the adhesive portion.

Further, the resin layer (B) is charged with other polymer components, a cross-linking agent, an antioxidant, an ultraviolet absorber, a filler, a polymerization inhibitor, a surface conditioner, and a charge, if necessary, as long as the characteristics are not impaired. Additives such as inhibitors, defoamers, viscosity modifiers, light-resistant stabilizers, weather-resistant stabilizers, heat-resistant stabilizers, antioxidants, leveling agents, organic pigments, inorganic pigments, pigment dispersants, silica beads, and organic beads; Those containing inorganic fillers such as silicon oxide, aluminum oxide, titanium oxide, zirconia, and antimony pentoxide can be used.

By using, for example, a phenolic anti-aging agent as the anti-aging agent, the heat-resistant stability of the styrene-isoprene copolymer or the like can be effectively improved, and as a result, good initial adhesiveness is maintained. However, it is preferable because an adhesive tape having even better thermal durability can be obtained.
The phenolic antiaging agent is generally a phenolic compound having a steric hindrance group, and is typically a monophenolic type, a bisphenol type, or a polyphenol type. Specific examples include 2,6-di-t-butyl-4-methylphenol, 2,2'-methylenebis (4-methyl-6-t-butylphenol), and 2,2'-methylenebis (4-ethyl-6). -T-butylphenol), 4,4'-thiobis (6-t-butyl-3-methylphenol), 4,4'-butylidenebis- (3-methyl-6-t-butylphenol), tetrakis- [methylene-3 -(3'5'-di-t-butyl-4-hydroxyphenyl) propionate] Methyl, n-octadecyl-3- (4'-hydroxy-3'5'-di-t-butylphenyl) propionate, etc. alone Alternatively, two or more types can be used in combination.

When the phenolic antiaging agent contains a styrene-isoprene block copolymer as the resin layer, it is in the range of 0.1 part by mass to 5 parts by mass with respect to 100 parts by mass of the styrene-isoprene block copolymer. It is preferable to use in the above, and when it is used in the range of 0.5 parts by mass to 3 parts by mass, the heat stability of the styrene-isoprene copolymer can be effectively improved, and as a result, a good initial stage is obtained. It is possible to obtain a resin layer that maintains adhesiveness and has even better thermal durability.
As the anti-aging agent, the phenol-based anti-aging agent and other anti-aging agents such as phosphorus-based anti-aging agent (also referred to as processing stabilizer), amine-based anti-aging agent, and imidazole-based anti-aging agent are used in combination. In particular, the combined use of the phenol-based anti-aging agent and the phosphorus-based anti-aging agent may provide a resin layer that maintains good initial adhesiveness and has even better thermal durability. Obtainable. Since the phosphorus-based antiaging agent may slightly discolor (yellow) over time in a high temperature environment, the amount of the phosphorus-based antiaging agent used balances the initial adhesiveness, thermal durability, and discoloration prevention. It is preferable to take it into consideration and set it appropriately.

The resin layer (B) is provided with a primer layer for the purpose of further improving the adhesion to the adhesive portion (C), and the surface is roughened by a sandblasting method, a solvent treatment method, or the like. Those that have undergone surface treatment such as corona discharge treatment, chromic acid treatment, flame treatment, hot air treatment, ozone treatment, ultraviolet irradiation treatment, and oxidation treatment can be used.

Examples of the method for producing the resin layer (B) include a cast method by extrusion molding, a uniaxial stretching method, a sequential secondary stretching method, a simultaneous biaxial stretching method, an inflation method, a tube method, and a calendar method and a solution method. ..

The resin layer (B) may have a single-layer structure, a two-layer structure, a three-layer structure, or a multi-layer structure. In the case of a multi-layer structure, it is preferable that at least one layer is a layer having the above-mentioned resin composition because it is easy to exhibit the required mechanical properties. Further, for example, a resin layer (B) having a three-layer structure can be obtained by a method of coextruding a thermoplastic resin such as polypropylene and the styrene-isoprene-styrene copolymer. This may be used as a suitable configuration for the adhesive tape of the present invention, for example, when it is desired to have appropriate dimensional stability and elasticity.

(Adhesive part (C))
Next, the adhesive portion (C) constituting the adhesive tape of the present invention will be described.
The adhesive portion (C) is directly provided on the surface (a) side of the resin layer (B) opposite to the foam layer (A). Between the two or more adhesive portions (C), there is a region in which the component constituting the adhesive portion (C) does not exist or may exist to such an extent that the adhesiveness is not exhibited.

Further, the region between the two or more adhesive portions (C) that does not have the adhesive portion (C) has a structure that leads to a part of the end portion (outer edge portion) of the adhesive tape. By using the adhesive tape having the above structure, even if a hole or the like is not provided in a part of the adhesive tape, air bubbles can be easily removed from the interface of the adhesive tape when it is attached to the adherend. Therefore, it is possible to prevent poor appearance due to swelling of the adhesive tape and to maintain excellent thermal conductivity (heat dissipation) and adhesive strength.

The shape of the adhesive portion (C) is substantially square when the adhesive tape of the present invention is observed from the surface (a) side of the resin layer (B) opposite to the foam layer (A). It is preferably hexagonal or substantially circular (FIGS. 2, 3 and 4), and the substantially circular shape facilitates air bubbles to escape from the interface with the adherend (air bleeding property). It is preferable because it can maintain good adhesive strength.

The substantially circular shape is not particularly limited, but the ratio [maximum diameter / minimum diameter] of the maximum diameter to the minimum diameter of any one adhesive portion is preferably 1 to 4. It is more preferably 1 to 2, and most preferably 1 to 1.5. As an example of the substantially circular shape, the shape as shown in FIG. 5 can be mentioned. The adhesive portions having the above shape are basically independent of each other, but as shown in FIG. 5, there may be a portion where two or more adhesive portions are partially connected.

Examples of the substantially quadrangular shape include a substantially square shape, a substantially rectangular shape, a substantially trapezoidal shape, a substantially rhombus shape, and the like. Moreover, it is preferable because it can maintain a good adhesive force.

The "abbreviation" such as the substantially quadrangular shape and the substantially hexagonal shape is described when, for example, a release liner or the like is attached to the surface of the adhesive portion (C), or when the adhesive tape is wound on a roll. It is shown that when the adhesive portion (C) is pressed, the square and hexagonal corners include a rounded shape and the straight portion includes a curved shape.

The substantially square corner portion preferably has a substantially rhombus shape in which the angle of the corner portion facing the flow direction of the adhesive tape is less than 90 °, and is preferably in the range of 45 ° to 70 °. It is more preferable because air bubbles can easily escape from the interface with the body (air escape property) and good adhesive strength can be maintained.

Further, it is preferable that any of the adhesive portions (c1) and the adhesive portion (c2) constituting the two or more adhesive portions (C) do not face each other in the flow direction and the width direction of the adhesive tape.

Further, the adhesive tape is often cut into an arbitrary shape and used depending on the intended use. At that time, when the adhesive tape is cut at an arbitrary position by arranging the adhesive portion (c1) and the adhesive portion (c2) so as not to face each other in the flow direction and the width direction, the end portion thereof. Since the adhesive portion (C) is present in a part of the adhesive tape, it is possible to suppress the peeling of the adhesive tape.

Further, with respect to the major axis of the contact region (r1) between the adhesive portion (c1) and the support measured by the method, the contact region (r2) between the adhesive portion (c1) and the release liner attached to the surface thereof. ) With the major axis [major axis of the contact region (r2) / major axis of the contact region (r1)] × 100 is preferably 97% to 110%, and is preferably in the range of 97% to 105%. It is more preferable to achieve both the ease of removing air bubbles from the interface with the adherend and the more excellent adhesiveness.

The adhesive tape of the present invention is an adhesive portion (c1) that satisfies the requirement of the ratio [contact area (s2) / contact area (s1)] × 100 among all the adhesive portions provided on the surface of the support. It is preferable to use one having a proportion of 50% to 100%, more preferably 80% to 100%, and even more preferably 90% to 100%. It is particularly preferable to use one having a content of 95% to 100% in order to maximize the effect of the present invention.

The distance between the adhesive portion (c1) selected from the two or more adhesive portions (C) and the adhesive portion (c2) close to the adhesive portion (c1) is preferably 0.5 mm or less, more preferably 0.5 mm or less. Is 0.05 mm to 0.2 mm, more preferably 0.06 mm to 0.15 mm, and 0.08 mm to 0.13 mm when a hole or the like is not provided in a part of the adhesive tape. However, it is particularly preferable because air bubbles can easily escape from the interface with the adherend (air escape property) and good adhesive strength can be maintained.

The adhesive portion any adhesive portion selected from (C) (c1) size per piece is preferably an area 0.001 mm ² 100 mm ^2, it is 0.01 mm 2 25 mm ² more ^preferably, more preferably from 0.015mm ² ~16mm 2, it is 0.02 mm ² to 5 mm ² is even the case without the hole or the like in a part of the adhesive tape to an adherend It is particularly preferable because air bubbles can easily escape from the interface (air escape property) and good adhesive strength can be maintained.

The adhesive portion (C) preferably exists in the range of the area of the adhesive tape of the present invention (square having a flow direction of 5 cm and a width direction of 5 cm), preferably 10 to 1,000,000, and preferably 1000 to 50,000. More preferably, the presence of 5000 to 40,000 is good because air bubbles can easily escape from the interface with the adherend (air escape property) even when a hole or the like is not provided in a part of the adhesive tape. It is particularly preferable because it can retain the adhesive force.

The ratio of the region having the adhesive portion (C) to the area of the surface (a) of the resin layer (B) opposite to the foam layer (A) is preferably 10% to 99%. It is more preferably 20% to 90%, more preferably 30% to 80%, and most preferably 35% to 80%. It is possible to form a substantially circular adhesive portion that is within the above range, and as a result, air bubbles escape from the interface with the adherend even when a hole or the like is not provided in a part of the adhesive tape. It is particularly preferable because it is possible to efficiently produce an adhesive tape that is easy (air bleeding property) and can maintain a good adhesive force. The ratio of the region is the area ratio of the adhesive portion (C) to the area of the square tape having a flow direction of 5 cm and a width direction of 5 cm.

The peak temperature of the loss tangent based on the dynamic viscoelastic spectrum measured at a frequency of 1 Hz of the adhesive portion (C) is not particularly limited, but is preferably −30 ° C. to 20 ° C. It is more preferably 20 ° C. to 10 ° C., and -10 ° C. to 5 ° C. makes it easy for air bubbles to escape from the interface with the adherend (air bleeding property) and can maintain good adhesive strength. As a result, it is more preferable because it is possible to more effectively prevent poor appearance due to swelling of the adhesive tape and performance deterioration such as thermal conductivity (heat dissipation), heat resistance and adhesive strength.

In the dynamic viscoelasticity measurement, a viscoelasticity tester (manufactured by Leometrics Co., Ltd., trade name: Ares 2KSTD) is used, and a test piece is sandwiched between parallel disks, which is the measurement part of the tester, and stored at a frequency of 1 Hz. The elastic modulus (G') and the loss elastic modulus (G ″) are measured. The loss tangent is calculated by the formula expressed by tan δ = (G ″) / (G ′). The peak temperature refers to the peak temperature confirmed by the spectrum of tan δ with respect to the measurement temperature range (-50 ° C to 150 ° C).

As the test piece, a pressure-sensitive adhesive layer having a thickness of 0.5 mm to 2.5 mm, which is formed by using the pressure-sensitive adhesive used for forming the pressure-sensitive adhesive portion (C), can be used.

Further, as the test piece, among a plurality of laminated adhesive tapes of the present invention, those having a total thickness of the adhesive layer of 0.5 mm to 2.5 mm can be used. When the test pieces having different configurations are used, the value of tan δ changes, but when the total thickness of the adhesive portion (C) in the test piece is the same, the peak temperature does not substantially change. .. Therefore, any test piece may be used for the measurement of the peak temperature.

As the adhesive portion (C), it is preferable to use one having a gel fraction of 10% by mass to 60% by mass, and it is more preferable to use one having a gel fraction of 20% by mass to 55% by mass. Preferably, it is preferable to use a gel having a gel content of 30% by mass to 50% by mass because the surface shape of the adhesive portion (C) is easily maintained even if it is thin, so that it can be prevented from changing over time. It is easy to remove air bubbles from the interface between the adherend and the adhesive portion (C), and as a result, the appearance is poor due to the swelling of the adhesive tape, and the thermal conductivity (heat dissipation) and heat resistance are high. It is more preferable because it can more effectively prevent performance deterioration such as property and adhesive strength. The gel fraction refers to a value measured by the following method.

The gel fraction refers to a value measured by the method shown below.
(1) The release-treated surface of the release liner (D) is coated with the adhesive so that the thickness after drying is 50 μm, dried in an environment of 100 ° C. for 3 minutes, and then 40 ° C. The pressure-sensitive adhesive layer was formed by aging for 2 days in the environment of.
(2) A test piece was obtained by cutting the adhesive layer into squares having a length of 50 mm and a width of 50 mm.
(3) After measuring the mass (G1) of the test piece, the test piece was immersed in toluene for 24 hours in an environment of 23 ° C.
(4) After the immersion, the mixture of the test piece and toluene was filtered using a 300 mesh wire mesh to extract an insoluble component in toluene. The mass (G2) of the insoluble component dried in an environment of 110 ° C. for 1 hour was measured.
(5) The gel fraction was calculated based on the mass (G1) and the mass (G2) and the following formula.
Gel fraction (mass%) = (G2 / G1) x 100

The adhesive portion (C) preferably has a thickness of 1 μm to 30 μm, more preferably 2 μm to 15 μm, and most preferably 4 to 8 μm. Air bubbles can be easily removed from the interface between the body and the adhesive portion (C), and as a result, the appearance is poor due to the swelling of the adhesive tape, and the performance such as thermal conductivity, heat resistance, and adhesive strength is improved. It is more preferable because the decrease can be prevented more effectively. The thickness of the adhesive portion (C) was measured according to JIS K6783 by a method using a dial gauge under the conditions that the contact surface of the dial gauge was flat, the diameter thereof was 5 mm, and the load was 1.23 N. Refers to the thickness of double-sided adhesive tape.

The adhesive portion (C) is, for example, an acrylic adhesive, a rubber adhesive, a silicone adhesive, a urethane adhesive, a polyester adhesive, a styrene-diene block copolymer adhesive, or a vinyl alkyl ether adhesive. It can be formed by using known pressure-sensitive adhesives such as polyamide-based pressure-sensitive adhesives, fluorine-based pressure-sensitive adhesives, creep property-improved pressure-sensitive adhesives, and radiation-curable pressure-sensitive adhesives. Among them, as the adhesive portion (C), it is preferable to use an adhesive portion obtained by using an acrylic pressure-sensitive adhesive because the adhesive reliability is excellent.

When the adhesive tape of the present invention having an adhesive portion (C) and / or a resin layer (B) on both sides of the foam layer (A) is used, the adhesive portion (C) and / or the resin layer (B) May use the adhesive portion (C) or the resin layer (B) having the same composition and gel fraction, but having different compositions and gel fractions.

As the acrylic pressure-sensitive adhesive, one containing an acrylic polymer can be used.

As the acrylic polymer, one obtained by polymerizing a monomer component containing a (meth) acrylic monomer such as a (meth) acrylic acid alkyl ester can be used.

Examples of the (meth) acrylic acid alkyl ester include methyl (meth) acrylate, ethyl (meth) acrylate, propyl (meth) acrylate, isopropyl (meth) acrylate, butyl (meth) acrylate, and (meth) acrylate. ) Isobutyl acrylate, s-butyl (meth) acrylate, t-butyl (meth) acrylate, pentyl (meth) acrylate, hexyl (meth) acrylate, heptyl (meth) acrylate, octyl (meth) acrylate , 2-Ethylhexyl (meth) acrylate, Isooctyl (meth) acrylate, Nonyl (meth) acrylate, Isononyl (meth) acrylate, decyl (meth) acrylate, Isodecyl (meth) acrylate, (meth) acrylate Undecyl, dodecyl (meth) acrylate, tridecyl (meth) acrylate, tetradecyl (meth) acrylate, pentadecyl (meth) acrylate, hexadecyl (meth) acrylate, heptadecyl (meth) acrylate, octadecyl (meth) acrylate , (Meta) nonadecil acrylate, Eikosyl (meth) acrylate and the like can be used alone or in combination of two or more. Among them, as the (meth) acrylic acid alkyl ester, it is preferable to use a (meth) acrylic acid alkyl ester having 1 to 20 carbon atoms of the alkyl group, and the alkyl group has 4 to 18 carbon atoms. It is more preferable to use the (meth) acrylic acid alkyl ester of. Examples of the alkyl group include a linear or branched alkyl group.

When butyl (meth) acrylate is used as the (meth) acrylic acid alkyl ester having 4 to 18 carbon atoms, the resin layer is prevented from being identified with the adhesive portion (C), and the adhesive portion and the adhesive portion are adhered. It is possible to suppress the disappearance of the region having no portion and easily maintain the surface shape of the resin layer (B). Therefore, it is preferable to obtain an adhesive tape that can easily prevent changes over time, easily allows air bubbles to escape from the interface with the adherend (air release property), and can maintain good adhesive strength.

As the (meth) acrylic monomer, in addition to the above-mentioned ones, a monomer having a carboxyl group such as (meth) acrylic acid, itaconic acid, maleic acid, fumaric acid, crotonic acid, isocrotonic acid, or an anhydride thereof. Monomer having a sulfonic acid group such as sodium vinyl sulfonate; Monomer having a cyano group such as acrylonitrile; Amid group such as acrylamide, metaacrylamide, N-vinylpyrrolidone, N, N-dimethyl (meth) acrylamide Monomer having a hydroxyl group such as hydroxyalkyl (meth) acrylate and glycerin dimethacrylate; Monomer having an amino group such as aminoethyl (meth) acrylate and acryloylmorpholin (meth); Monomer having an imide group such as cyclohexylmaleimide and isopropylmaleimide; Monomer having an epoxy group such as glycidyl (meth) acrylate and methylglycidyl (meth) acrylate; Monomer, triethylene glycol di (meth) acrylate, diethylene glycol di (meth) acrylate, ethylene glycol di (meth) acrylate, tetraethylene glycol di (meth) acrylate, neopentyl glycol di (meth) acrylate, 1,6 -Hexanediol di (meth) acrylate, trimethylolpropantri (meth) acrylate, pentaerythritol tri (meth) acrylate, dipentaerythritol hexa (meth) acrylate, divinylbenzene and other monomers are used alone or in combination of two or more. can do.

In addition to the (meth) acrylic monomer, the monomer includes aromatic vinyl compounds such as styrene and substituted styrene; olefins such as ethylene, propylene and butadiene; vinyl esters such as vinyl acetate; Vinyl chloride or the like can also be used.

The acrylic polymer can be produced by polymerizing the monomer by a method such as a solution polymerization method, a bulk polymerization method, a suspension polymerization method, an emulsion polymerization method, or the like, and the solution polymerization method can be adopted. , Preferable for improving the production efficiency of the acrylic polymer.

Examples of the solution polymerization method include a method in which the monomer, a polymerization initiator, and an organic solvent are mixed and stirred at a temperature of preferably 40 ° C. to 90 ° C. to carry out radical polymerization.

Examples of the polymerization initiator include peroxides such as benzoyl peroxide and lauryl peroxide, azo-based thermal polymerization initiators such as azobisisobutylnitrile, acetophenone-based photopolymerization initiators, benzoin ether-based photopolymerization initiators, and benzyl. Ketal-based photopolymerization initiators, acylphosphine oxide-based photopolymerization initiators, benzoin-based photopolymerization initiators, benzophenone-based photopolymerization initiators, and the like can be used.

The acrylic polymer obtained by the above method may be in a state of being dissolved or dispersed in an organic solvent, for example, when it is produced by a solution polymerization method.

As the acrylic polymer obtained by the above method, it is preferable to use one having a weight average molecular weight of 300,000 to 1.2 million, and more preferably one having a weight average molecular weight of 400,000 to 1.1 million. It is preferable to use an adhesive tape having a weight average molecular weight of 500,000 to 1,000,000 in order to obtain an adhesive tape having even better adhesive strength and ease of removing air bubbles even if it is thin.

The weight average molecular weight refers to a value measured by gel permeation chromatography (GPC method) and converted to standard polystyrene. Specifically, the weight average molecular weight can be measured under the following conditions using a GPC apparatus (HLC-8329GPC) manufactured by Tosoh Corporation.

Sample concentration: 0.5% by mass (tetrahydrofuran solution)
Sample injection volume: 100 μl
Eluent: tetrahydrofuran Flow velocity: 1.0 ml / min Measurement temperature: 40 ° C
Main column: 2 TSKgel GMHHR-H (20) Guard column: TSKgel HXL-H
Detector: Differential refractometer Weight average molecular weight of standard polystyrene: 10,000 to 20 million (manufactured by Tosoh Corporation)

As the pressure-sensitive adhesive that can be used for forming the pressure-sensitive adhesive portion (C), one containing a tack-imparting resin is used in order to form a pressure-sensitive adhesive portion having even more excellent adhesive strength, tensile strength and tensile breaking strength. Is preferable.

Examples of the tackifier resin include rosin-based tackifier resins, polymerized rosin-based tackifier resins, polymerized rosin ester-based tackifier resins, rosinphenol-based tackifier resins, stabilized rosin ester-based tackifier resins, and disproportionate rosin esters. A petroleum resin-based tackifier resin such as a hydrogenated rosin ester-based tackifier resin, a terpen-based tackifier resin, a terpenphenol-based tackifier resin, and a styrene-based tackifier resin can be used.

As the pressure-sensitive adhesive resin, it is possible to use a combination of a rosin-based pressure-sensitive adhesive resin and a petroleum resin-based pressure-sensitive adhesive resin, which has even better adhesive strength and ease of removing air bubbles even if it is thin. It is preferable to obtain. The rosin-based tackifier resin and the petroleum resin-based tackifier resin are particularly preferably used in combination with the acrylic polymer, and the acrylic polymer obtained by polymerizing a monomer containing butyl (meth) acrylate. It is preferable to use them in combination in order to obtain an adhesive tape having even better adhesive strength and ease of removing air bubbles even if it is thin.

Further, as the tackifier resin, it is preferable to use a tackifier resin that is liquid at room temperature in order to further improve the initial adhesive strength of the pressure-sensitive adhesive portion (C). Examples of the tackifier resin that is liquid at room temperature include low molecular weight liquid rubbers such as process oils, polyester plasticizers, and polybutenes. Terpene phenol resins can be used. Commercially available products are YP manufactured by Yasuhara Chemical Co., Ltd. -90L and the like can be mentioned.

The tackifier resin is preferably used in the range of 20 parts by mass to 60 parts by mass, and even more excellently used in the range of 30 parts by mass to 55 parts by mass with respect to 100 parts by mass of the acrylic polymer. It is more preferable to obtain an adhesive tape having a strong adhesive force.

The pressure-sensitive adhesive constituting the pressure-sensitive adhesive portion (C) contains, if necessary, a softening agent, a plasticizer, a filler, an anti-aging agent, a coloring agent, and the like, in addition to the acrylic polymer and the like. Can be used.

Among them, the use of a cross-linking agent can adjust the gel fraction of the adhesive portion (C) to a suitable range, and as a result, the shape of the adhesive portion (C) can be easily maintained. It is preferable because it is easy to prevent such changes, air bubbles can be easily removed from the interface between the adherend and the resin layer (B), and an adhesive tape having excellent adhesive strength can be obtained.

As the cross-linking agent, for example, an isocyanate cross-linking agent or an epoxy cross-linking agent is preferably used.

As the isocyanate cross-linking agent, for example, tolylene diisocyanate, naphthylene-1,5-diisocyanate, hexamethylene diisocyanate, diphenylmethane diisocyanate, xylylene diisocyanate, trimethylolpropane-modified tolylene diisocyanate and the like can be used. It is preferable to use a toluene diisocyanate adduct such as trimethylol propane-modified tolylene diisocyanate. The toluene diisocyanate adduct has a structure derived from toluene diisocyanate in the molecule, and examples of commercially available products include Coronate L (manufactured by Nippon Polyurethane Industry Co., Ltd.).

When the isocyanate cross-linking agent is used, it is preferable to use an acrylic polymer having a hydroxyl group as the acrylic polymer. The acrylic polymer having a hydroxyl group has, as a monomer used for its production, for example, 2-hydroxyethyl (meth) acrylate, 4-hydroxybutyl (meth) acrylate, 6-hydroxyhexyl (meth) acrylate and the like. , And more preferably 2-hydroxyethyl (meth) acrylate and 4-hydroxybutyl (meth) acrylate.

Further, as the epoxy cross-linking agent, for example, Tetrad X or Tetrad C manufactured by Mitsubishi Gas Chemical Company, Inc., E-05X manufactured by Soken Kagaku Co., Ltd., or the like can be used.

When the epoxy cross-linking agent is used, it is preferable to use an acrylic polymer having an acid group as the acrylic polymer. For the acrylic polymer having an acid group, for example, (meth) acrylic acid, acrylic acid dimer, itaconic acid, crotonic acid, maleic acid, maleic anhydride and the like are preferably used as the monomer used for the production thereof. , (Meta) acrylic acid is more preferred.

As the pressure-sensitive adhesive that can be used for forming the pressure-sensitive adhesive portion (C), it is preferable to use one containing a solvent, if necessary. As the pressure-sensitive adhesive, it is preferable to use one having a viscosity adjusted to the range of 0.1 mPa · s to 1000 mPa · s, and one having a viscosity adjusted to the range of 1 mPa · s to 200 mPa · s is used. It is more preferable, and it is more preferable to use one adjusted in the range of 10 mPa · s to 100 mPa · s because it is easy to form the adhesive portion (C) having a predetermined shape.

(Peeling liner (D))
The adhesive tape of the present invention may have a release liner (D) on the surface in contact with the adhesive portion (C).
The release liner (D) is a pressure-sensitive adhesive coated with a release agent. As the pressure-sensitive adhesive, a polyester film, a polyimide film, a polyolefin film and the like can be used. Among them, polyethylene terephthalate film is preferable because it has good heat resistance and strength and is low in cost. The thickness of the pressure-sensitive adhesive is not particularly limited, but is preferably 25 μm to 125 μm, and more preferably 50 μm to 100 μm. When it is in the above range, the shape of the adhesive portion (C) is easily maintained, which is preferable.
The release agent is not particularly limited, but a silicone-based agent is preferable because the peeling force can be easily adjusted.

(Manufacturing method of foam layer)
In the method for producing the foam layer (A), the foam layer (A) is produced by reacting a laminate obtained by applying a foam raw material or the like on the resin layer (B) according to the material of the foam layer to be applied. Can be appropriately selected from a manufacturing method for forming the resin layer (B) and a manufacturing method for forming the resin layer (B) on the release liner and bonding the resin layer (B) to the foam layer (A).

An example in which a polyurethane foam layer is produced as the foam layer (A) will be described. The raw materials for producing the polyurethane foam layer are a gas-liquid mixture containing a foam raw material and a gas having the above constitution, and a resin layer (B). The gas mixed with the foam raw material is not particularly limited, and nitrogen gas, inert gas, dry air and the like can be used. Of these, nitrogen gas is preferable. Hereinafter, a method for producing the polyurethane foam laminate will be specifically described below.

The foam raw material and the gas are stirred or the like using a mixer to obtain a gas-liquid mixture. Then, the gas-liquid mixture is supplied so as to be applied onto the resin layer (B), and then the surface of the gas-liquid mixture to be cast is coated with a release paper (or a release treatment) from above. Agent) is supplied. Then, the thickness of the uncured layer made of the gas-liquid mixture is adjusted by passing it through a roll coater or the like in this laminated state. It does not matter whether or not the paper pattern is used, but if the paper pattern 7 is used, the thickness of the uncured layer can be easily adjusted, and the surface of the foam layer (A) obtained after the heat treatment (the paper pattern side). ) Can form a skin layer. By these steps, a three-layer type laminate having a resin layer (B) on one surface side (lower surface) of the uncured layer and a release paper laminated on the other surface side (upper surface) is obtained.

Then, this laminate is heated by a heat treatment apparatus. As a result, the polyurethane foam laminate in which the foam layer (A) is formed can be obtained by reacting the foam raw material and curing the uncured layer. By this manufacturing method, the polyurethane foam layer (A) and the resin layer (B) are firmly bonded. The obtained laminate may be wound around a paper tube or the like to form a roll while maintaining the three-layer structure, or may be wound as a two-layer laminate after the release paper is peeled off to form a roll. Further, it can be cut into a predetermined size on the production line to obtain a sheet. The sheets may then be stacked and packed. In this case as well, the three layers may be stacked as they are, or they may be stacked as a two-layer laminated body.

As described above, the raw materials for producing the polyurethane foam laminate are a gas-liquid mixture obtained by using a foam raw material and a gas, and a resin layer (B).
The method for preparing the foam raw material is not particularly limited, but preferably, a polyisocyanate and a mixture containing a polyol, a flame retardant, a catalyst, etc. without containing the polyisocyanate (hereinafter referred to as "first mixture") are used. It is a method of mixing. Additives to be blended as needed are usually included in the first mixture.

The method for preparing the gas-liquid mixture is not particularly limited, and when the volume ratio of the foam raw material and the gas is 100% by volume in total, it is preferably 5 to 30% by volume and 70 to 95% by volume, respectively. , More preferably, the foam raw material and the gas are mixed so as to be 8 to 25% by volume and 75 to 92% by volume. With this mixing ratio, a gas-liquid mixture suitable for forming the foam layer having the specific density can be prepared. The mixer used for mixing the foam raw material and the gas is not particularly limited, but an oak mixer, a hobert mixer, or the like is preferably used. With these mixers, the foam raw material and the gas can be uniformly mixed, foaming can be easily controlled, and the foamed gas-liquid mixture can be produced as a more homogeneous one.

The method of mixing the foam raw material and the gas is preferably a method of blowing a gas into the foam raw material previously housed in a mixing chamber or the like, and a method of simultaneously mixing the foam raw material and the gas into the chamber. It is a method of supplying. In these cases, the foam raw material may separately supply the polyisocyanate and the first mixture to this chamber.

The foam layer (A) using the gas-liquid mixture is preferably formed by the mechanical floss method. According to this method, the volume of the gas-liquid mixture used and the volume of the obtained polyurethane foam can be made substantially the same. Therefore, the density of the polyurethane foam can be adjusted by the composition of the gas-liquid mixture, that is, the amount of gas introduced into the foam raw material.

The gas-liquid mixture is supplied to the surface of the resin layer (B), and then a paper pattern is supplied from above to the surface of the gas-liquid mixture to be cast to form a laminate. Next, this three-layer type laminate is heated by a heat treatment apparatus set to a predetermined temperature, and the foam raw material contained in the uncured layer is reacted to form the foam layer (A).

The heating method of the three-layered laminate is not particularly limited, and is appropriately selected depending on the type of heat treatment apparatus and the like.

The heating temperature is appropriately selected according to the types of the polyol and the polyisocyanate in order to cure the foam raw material contained in the uncured layer. The heating temperature is preferably 120 ° C. to 200 ° C., preferably 140 ° C. to 180 ° C., and particularly preferably 150 ° C. to 170 ° C.

The heating time is preferably 1 to 10 minutes, more preferably 1 to 5 minutes.

Examples of the heat treatment apparatus include a heating furnace and a far-infrared irradiation apparatus. When a heating furnace is used, heat treatment can be performed while the three-layered laminate is stationary or moving by using a heat source fixed in the apparatus. At this time, hot air may be supplied. When the polyurethane foam laminate is continuously produced, it is preferable to heat the three-layer laminate while moving it in a heating furnace.

The heating of the three-layered laminate can be performed from either one side or both sides of the pressure-sensitive adhesive side and the release paper side. In the present invention, in order to uniformly heat the whole and efficiently form a more homogeneous foam layer (A), it is preferable to heat from both sides of the three-layer type laminate.

When the manufacturing method of the polyurethane foam laminate is the above-mentioned manufacturing system, preparation of the gas-liquid mixture, supply of the gas-liquid mixture onto the resin layer (B), release paper on the upper surface of the uncured layer, etc. The polyurethane foam laminate can be continuously produced by continuously advancing the supply of the resin, the thickness adjustment by a roll coater, and the heating of the three-layer laminate. That is, the gas-liquid mixture prepared by the mixer is continuously supplied onto the moving resin layer (B) at a predetermined supply rate, and is continuously supplied to the surface of the flowing gas-liquid mixture. , The paper pattern is supplied at the same speed as the resin layer (B), and the thickness is adjusted by the roll coater. The three-layer laminate is then introduced into a heat treatment apparatus, eg, a heating furnace, located close to the roll coater. When a heating furnace is used, a three-layer laminate is usually introduced from one opening, moved in the heating furnace at the same or similar moving speed as the resin layer (B), and from the other opening. You can derive it. As a result, a polyurethane foam laminate having a release paper is produced. After that, if necessary, the release paper can be removed to obtain a polyurethane foam laminate composed of the foam layer (A) and the resin layer (B).

As described above, the polyurethane foam laminate can be produced by a mechanical floss method in which water and a foaming agent are not mixed with the foam raw material. It can also be produced by the so-called chemical floss method, in which water and / or a foaming agent is mixed with the foam raw material. In this case, as the water, ion-exchanged water, tap water, distilled water and the like can be used. The amount of water used is not particularly limited, but when the polyol is 100 parts by mass, it is usually 0.1 to 0.5 parts by mass, and particularly preferably 0.2 to 0.4 parts by mass. Further, the foaming agent is not particularly limited, and hydrocarbons, CFC substitutes and the like can be used. The amount of this foaming agent used is also not particularly limited. As described above, even in the case of the chemical floss method using a foam raw material containing water and / or a foaming agent instead of the mechanical floss method, the foaming state of the gas-liquid mixture is stably maintained and the cell is roughened. The foam layer (A) having a desired density and thickness can be easily formed without causing the above. As a result, a polyurethane foam laminate having a foam layer (A) having excellent physical properties can be obtained.

Next, a case of producing an acrylic foam will be described. As the raw material of the acrylic foam, for example, an acrylic emulsion, a foaming agent (anionic surfactant), water as a dispersion medium, a cross-linking agent and other additives can be used (note that it is used in the foaming step). The gas for foaming will be described in the foaming process).

An aqueous dispersion of an acrylic resin can be used as the acrylic emulsion, and the production method thereof is, for example, in the presence of a polymerization initiator, an emulsifier and a dispersion stabilizer if necessary, for example, a (meth) acrylic acid ester-based simple emulsion. It can be obtained by using a metric as an essential polymerizable monomer component and, if necessary, copolymerizing a mixture of other polymerizable monomers copolymerizable with these monomers. Two or more kinds of acrylic emulsions may be used in combination.

Examples of the polymerizable monomer that can be used in the preparation of the acrylic emulsion include methyl (meth) acrylate, ethyl (meth) acrylate, propyl (meth) acrylate, butyl (meth) acrylate, and (meth). ) Hexyl acrylate, (meth) heptyl acrylate, octyl (meth) acrylate, octadecyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, cyclohexyl (meth) acrylate, nonyl (meth) acrylate, (meth) (Meta) acrylates such as dodecyl acrylate, stearyl (meth) acrylate, isobornyl (meth) acrylate, dicyclopentanyl (meth) acrylate, phenyl (meth) acrylate, benzyl (meth) acrylate, etc. Ester-based monomers; acrylic acid, methacrylic acid, β-carboxyethyl (meth) acrylate, 2- (meth) acryloyl propionic acid, crotonic acid, itaconic acid, maleic acid, fumaric acid, itaconic acid half ester, maleic acid half Unsaturated bond-containing monomer having a carboxyl group such as ester, maleic anhydride, itaconic anhydride; glycidyl group-containing polymerizable monomer such as glycidyl (meth) acrylate and allyl glycidyl ether; 2-hydroxyethyl (meth) Hydroxyl group-containing polymerizable monomers such as acrylate, 2-hydroxypropyl (meth) acrylate, polyethylene glycol mono (meth) acrylate, and glycerol mono (meth) acrylate; ethylene glycol di (meth) acrylate, 1,6-hexanediol di. (Meta) Acrylate, Neopentyl Glycol Di (Meta) Acrylate, Trimethylol Propanetri (Meta) Acrylate, Polyethylene Glycol Di (Meta) Acrylate, Polypropylene Glycol Di (Meta) Acrylate, Dialyl Falate, Divinyl benzene, Allyl (Meta) Acrylate Etc. can be exemplified.

When an emulsifier is used in the preparation of the acrylic emulsion, a known emulsifier or the like may be used.

The viscosity of the acrylic emulsion is preferably 5,000 to 20,000 mPa · s, more preferably 8,000 to 15,000 mPa · s, as measured by a Brookfield viscometer (25 ° C.). When the viscosity is 5,000 or more, the foam holding force at the time of molding is sufficient, and finer cells can be molded. When the viscosity is 20,000 or less, the shearing force to the raw material can be reduced at the time of molding, so that it is possible to prevent the cells having a distorted shape from being molded.

Water is an essential component of the dispersion medium of the acrylic emulsion, but it may be a mixture of water and a water-soluble solvent. The water-soluble solvent is, for example, alcohols such as methyl alcohol, ethyl alcohol, isopropyl alcohol, ethyl carbitol, ethyl cellosolve, butyl cellosolve, polar solvents such as N-methylpyrrolidone, and one or more of these. A mixture of the above may be used.

The acrylic emulsion may contain an anionic surfactant (foaming anionic surfactant) as a foaming agent in the emulsion composition.
Specific examples of the anionic surfactant include sodium laurate, sodium myristate, sodium stearate, ammonium stearate, sodium oleate, potassium oleate soap, potassium castor oil soap, potassium palm oil soap, and lauroyl sarcosin. Sodium, myristyl sarcosin sodium, oleyl sarcosin sodium, cocoyl sarcosin sodium, coconut oil alcohol sodium sulfate, polyoxyethylene lauryl ether sodium sulfate, sodium alkyl sulfosuccinate, sodium lauryl sulfoacetate, sodium alkylbenzene sulfonate, sodium α-olefin sulfonate Etc., but sodium alkylsulfosuccinate is particularly preferable.

Here, the anionic surfactant used in this embodiment preferably has an HLB of 10 or more, more preferably 20 or more, and 30 or more, in order to facilitate dispersion in the emulsion composition. Is particularly preferable.

In addition to the above-mentioned anionic surfactant, the acrylic emulsion can further contain an amphoteric surfactant, whereby bubbles can be made fine and uniform.
In particular, when an anionic surfactant and an amphoteric surfactant are used in combination, the charge of the hydrophilic group between the molecules of the anionic surfactant repels each other, and the molecules of the anionic surfactant maintain a certain distance from each other. In addition, the electrically neutral double-sided activator penetrates between the molecules of the anionic surfactant, so that the bubbles can be more stabilized and the size of the bubbles can be reduced. Therefore, it is preferable to use an anionic surfactant and an amphoteric surfactant in combination.

The amphoteric tenside is not particularly limited, and amphoteric surfactants such as amino acid type, betaine type and amine oxide type can be used. Betaine-type amphoteric surfactants are suitable because they have higher effects as described above. Further, from the viewpoint of easy entry of the anionic surfactant between the molecules, those of C10 to 12 are preferable.

Examples of the amino acid type amphoteric surfactant include N-alkyl or alkenyl amino acids or salts thereof. An N-alkyl or alkenyl amino acid has an alkyl or alkenyl group attached to a nitrogen atom and further one or two "-R-COOH" (in the formula, R represents a divalent hydrocarbon group, preferably a divalent hydrocarbon group. It is an alkylene group, and particularly preferably has 1 to 2 carbon atoms.) It has a structure in which a group represented by the group is bonded. In the compound in which one "-R-COOH" is bonded, a hydrogen atom is further bonded to the nitrogen atom. One "-R-COOH" is called a mono body, and two "-R-COOH" are called a di body. As the amphoteric surfactant, either mono-form or di-form can be used. In N-alkyl or alkenyl amino acids, the alkyl group and the alkenyl group may be linear or branched chain. Specific examples of the amino acid type amphoteric tenside include sodium lauryldiaminoethylglycine, sodium trimethylglycine, sodium cocoyl taurine, sodium cocoyl methyl taurine, sodium lauroyl glutamate, potassium lauroyl glutamate, and lauroyl methyl-β-alanine. Be done.

Examples of betaine-type amphoteric surfactants include alkyl betaine, imidazolinium betaine, carbobetaine, amide carbobetaine, amide betaine, alkylamide betaine, sulfobetaine, amide sulfobetaine, and phosphobetaine. Specifically, as betaine-type amphoteric surfactants, lauryl betaine, stearyl betaine, lauryldimethylaminoacetic acid betaine, stearyldimethylaminoacetic acid betaine, lauric acid amidopropyldimethylaminoacetic acid betaine, isostearate amidoethyldimethylaminoacetic acid betaine, Isostearate amidopropyldimethylaminoacetic acid betaine, isostearate amidoethyldiethylaminoacetate betaine, isostearate amidopropyldiethylaminoacetic acid betaine, isostearate amidoethyldimethylaminohydroxysulfobetaine, isostearate amidopropyldimethylaminohydroxysulfobetaine, isostearate amidoethyldiethylamino Hydroxysulfobetaine, isostearate amidopropyl diethylaminohydroxysulfobetaine, N-lauryl-N, N-dimethylammonium-N-propylsulfobetaine, N-lauryl-N, N-dimethylammonium-N- (2-hydroxypropyl) sulfo Betaine, N-lauryl-N, N-dimethyl-N- (2-hydroxy-1-sulfopropyl) ammonium sulfobetaine, laurylhydroxysulfobetaine, dodecylaminomethyldimethylsulfopropyl betaine, octadecylaminomethyldimethylsulfopropyl betaine, 2 -Alkyl-N-carboxymethyl-N-hydroxyethyl imidazolinium betaine (2-lauryl-N-carboxymethyl-N-hydroxyethyl imidazolinium betaine 2-stearyl-N-carboxymethyl-N-hydroxyethyl imidazolinium) Betaine, etc.), coconut oil fatty acid amide propyl betaine, coconut oil fatty acid amide propyl hydroxysultaine and the like.

Examples of the amine oxide type amphoteric surfactant include lauryldimethylamine-N-oxide and oleyldimethylamine-N-oxide.

Among the amphoteric tensides described above, it is preferable to use a betaine type amphoteric surfactant, and among the betaine types, alkyl betaine, imidazolinium betaine, and carbobetaine are particularly preferable. Examples of the alkyl betaine include stearyl betaine and lauryl betaine, and examples of the imidazolinium betaine include 2-alkyl-N-carboxymethyl-N-hydroxyethyl imidazolinium betaine.

The acrylic emulsion can contain a cross-linking agent as a curing agent. This makes it possible to improve the strength of the foam.
The cross-linking agent is not particularly limited, and a required amount may be added depending on the intended use. Examples of the cross-linking method using a cross-linking agent include physical cross-linking, ionic cross-linking, and chemical cross-linking, and the cross-linking method can be selected according to the type of water-dispersible resin. As the cross-linking agent, a known cross-linking agent can be used, and a sensory compound containing an epoxy-based cross-linking agent, a melamine-based cross-linking agent, an isocyanate-based cross-linking agent, a carbodiimide-based cross-linking agent, an oxazoline-based cross-linking agent, and the like is contained. An appropriate amount can be used depending on the type of group and the amount of functional group. Epoxy-based cross-linking agents and isocyanate-based cross-linking agents are preferable in order to improve the adhesive strength, tack strength and delamination strength. The isocyanate-based and epoxy-based cross-linking agents can prevent the material destruction of the adherend and the porous foam by increasing the material strength. Of these, aliphatic isocyanates are more preferable. Two or more of these cross-linking agents may be used in combination.

Acrylic emulsion is a surfactant for dispersing water-dispersible resin, which is a surfactant for dispersing water-dispersible resin (unlike anionic surfactant, it does not have to have an effect as a foaming agent). May be contained. Such a surfactant may be appropriately selected depending on the water-dispersible resin to be selected.

In the emulsion composition, the blending amount of the water-dispersible resin (solid content) with respect to the liquid medium is preferably 30 to 80 parts by mass with respect to 100 parts by mass of the liquid medium. Within such a range, an effect that a stable foam can be molded can be obtained.
Unless otherwise specified, the blending amount and blending ratio are based on the solid content, and the components constituting the "solid content" are the components obtained by removing the dispersion medium from the emulsion. Specifically, it contains a surfactant, a filler, and the like in addition to the resin.

The amount of the anionic surfactant to be blended is preferably 1.0 to 10 parts by mass based on the total amount of the emulsion (the total amount of solid content and non-solid content is 100 parts by mass) in the emulsion composition. More preferably, 3 to 10 parts by mass. Within such a range, it is easy to form an appropriate foam, and an effect that a fine cell structure can be formed can be obtained.

The amount of the amphoteric surfactant to be blended is preferably 0.5 to 10 parts by mass, based on the total amount of the emulsion (the total amount of solid content and non-solid content is 100 parts by mass) in the emulsion composition. 1 to 5 parts by mass is more preferable. Within such a range, it is easy to form an appropriate foam, and an effect that a fine cell structure can be formed can be obtained.

As for the blending amount of the cross-linking agent (curing agent), the mass ratio of the cross-linking agent (the cross-linking agent / the acrylic emulsion) to the acrylic emulsion (solid content) in the emulsion composition is 0.01 to 0.12. is there. It is preferably 0.025 to 0.05. Within such a range, a foam having a small residual compression strain can be molded.

The method for producing an acrylic foam is a raw material preparation step and a foaming / curing step (an emulsion composition containing at least an emulsion and a foaming agent is foamed by a mechanical floss method to form a foam, and the foam is formed. The step of curing the foam) and. The emulsion composition may further contain a cross-linking agent, and in the above step, energy may be applied to cross-link the resin constituting the emulsion via the cross-linking agent to cure the foam. Hereinafter, each step will be described in detail.

In the raw material preparation step, an emulsion composition which is a raw material mixture of foams is prepared by mixing each raw material as described above. The mixing method at this time is not particularly limited, but for example, it may be mixed while stirring in a container such as a mixing tank in which each component is mixed.

In the foaming / curing step, a predetermined foaming gas is added to the emulsion composition obtained in the raw material preparation step, and these are sufficiently mixed to allow a large number of bubbles to exist in the emulsion composition (foaming emulsion composition). ). This foaming / curing step is usually carried out by sufficiently mixing the raw material mixture of the liquid porous foam obtained in the raw material preparation step with the foaming gas by a mixing device such as a mixing head.

The foaming gas mixed in the emulsion composition in the stirring / foaming step forms bubbles (cells) in the foam, and the foaming ratio and density of the obtained foam are determined by the amount of the foaming gas mixed. Is decided. In order to adjust the density of the porous foam, it is necessary from the desired density of the porous foam and the volume of the raw material of the porous foam (for example, the internal volume of the mold into which the raw material of the porous foam is injected). The mass of the raw material of the porous foam may be calculated, and the amount of the foaming gas may be determined so as to have a desired volume at this mass. Air is mainly used as the type of gas for foaming, but other inert gases such as nitrogen, carbon dioxide, helium, and argon can also be used.

As the foaming method used in the method for preparing an acrylic foam produced by using an acrylic emulsion, a mechanical floss (mechanical floss) method can be used. The mechanical floss method is a method in which air in the atmosphere is mixed with the emulsion composition and foamed by stirring the emulsion composition with a stirring blade or the like. As the stirring device, a stirring device generally used in the mechanical floss method can be used without particular limitation, and for example, a homogenizer, a dissolver, a mechanical floss foaming machine, or the like can be used. According to this mechanical floss method, by adjusting the mixing ratio of the emulsion composition and air, it is possible to obtain a porous foam having a density suitable for various uses.

The mixing time of the emulsion composition and air is not particularly limited, but is usually 1 to 10 minutes, preferably 2 to 6 minutes. The mixing temperature is not particularly limited, but is usually room temperature. The stirring speed in the above mixing is preferably 200 rpm or more (more preferably 500 rpm or more) in order to make the bubbles finer, and preferably 2000 rpm or less (800 rpm or less is preferable) in order to smooth the discharge of the foam from the foaming machine. More preferable).

The emulsion composition foamed as described above (foamed emulsion composition) is formed into a sheet-shaped acrylic foam layer having a desired thickness by, for example, a known means such as a doctor knife or a doctor roll. ..

As a method for curing the foam, a known method can be used. The acrylic foam can be self-crosslinked, but the foam may be cured by applying energy to crosslink the resin constituting the emulsion via a cross-linking agent. The step of applying energy is not particularly limited, and examples thereof include a heating step (thermal cross-linking).

In the heating step, the dispersion medium in the molded foamed emulsion composition is evaporated. The drying method at this time is not particularly limited, but for example, hot air drying or the like may be used. The drying temperature and drying time are not particularly limited, but may be, for example, about 1 to 3 hours at about 80 ° C.

Further, in this heating step, the dispersion medium evaporates from the foamed emulsion composition, and the path through which the vapor escapes is communicated from the inside to the outside of the porous foam. Therefore, in this foam, since the passage when water vapor escapes remains as open cells, at least a part of the bubbles existing in the porous foam becomes open cells. Here, if the foaming gas mixed in the stirring / foaming step remains as it is, it becomes closed cells in the obtained porous foam, and the mixed foaming gas releases steam in this step. When communicated with each other, open cells are formed in the obtained porous foam. That is, a structure is such that some of the bubbles in the porous foam are open cells and the remaining bubbles are closed cells, resulting in a semi-open cell structure in which open cells and closed cells are mixed.

When a cross-linking agent is added, the heating step proceeds and completes the cross-linking (curing) reaction of the raw material. Specifically, the raw materials are crosslinked with each other by the above-mentioned cross-linking agent to form a cured porous foam. The heating means at this time is not particularly limited as long as the raw material can be sufficiently heated and the raw material can be crosslinked (cured), but for example, a tunnel type heating furnace or the like can be used. Further, the heating temperature and heating time may be any temperature and time at which the raw materials can be crosslinked (cured), and may be, for example, about 1 hour at 80 to 150 ° C. (particularly about 120 ° C.). ..

(Manufacturing method of adhesive tape)
As a method for producing an adhesive tape of the present invention, for example, a resin layer (B) is formed on a release liner (E), bonded to the foam layer (A), and then the pressure-sensitive adhesive is applied to the release liner (D). Was applied intermittently and dried to form an adhesive portion (C), and the surface (resin layer (resin layer (resin layer)) from which the release liner (E) was peeled off, although the foam layer (A) and the resin layer (B) were integrated. A method of sticking the adhesive portion (C) to the B) side) can be mentioned. As the release liner (E), any one can be used, and the same one as the release liner (D) can be used.

Since the adhesive tape of the present invention has excellent adhesive strength, cushioning property, and sticking workability (air bubble removal property) even if it is very thin, for example, an electronic device such as a portable electronic terminal that is required to be thin. Can be suitably used in the manufacturing scene of. In particular, by using it on the back surface of a display, it is possible to prevent cracking and pooling of the display device and contribute to thinning.

Further, in the adhesive tape, even if a hole or the like is not provided in a part of the adhesive tape, air bubbles can easily escape from the interface between the adherend and the adhesive portion (B), and holes are formed to improve the stickability. Since no processing is required, it can be suitably used on the back surface of a display where there is a concern that the performance may be deteriorated due to the residual bubbles. Further, the adhesive tape can maintain the airtightness between the adhesive tape and the adherend, and the adhesive tape is applied to the back surface (attachment surface) of a display such as an organic EL display in which moisture should be avoided from entering. Suitable for

Examples of the present invention will be described below and will be described in more detail.

(Preparation Example 1) Adhesive (c-1)
Ethyl acetate using 97.98 parts by mass of n-butyl acrylate, 2 parts by mass of acrylic acid, 0.02 part by mass of 4-hydroxybutyl acrylate, and 0.2 parts by mass of azobisisobutyronitrile as a polymerization initiator. An acrylic polymer having a weight average molecular weight of 900,000 was obtained by solution-polymerizing in a solution at 80 ° C. for 8 hours.

5 parts by mass of "D-135" (manufactured by Arakawa Chemical Industry Co., Ltd., polymerized rosin ester) and "KE-100" (manufactured by Arakawa Chemical Industry Co., Ltd., disproportionated rosin) with respect to 100 parts by mass of the acrylic polymer. 20 parts by mass of ester) and 25 parts by mass of "FTR6100" (manufactured by Mitsui Chemicals, Inc., petroleum resin) were mixed, and ethyl acetate was further added to obtain a pressure-sensitive adhesive solution adjusted to a solid content of 40% by mass. ..

The pressure-sensitive adhesive solution was mixed with 2.0 parts by mass of "NC40" (manufactured by DIC Corporation, isocyanate cross-linking agent) and stirred to obtain the pressure-sensitive adhesive a.
The peak temperature of tan δ of the pressure-sensitive adhesive layer obtained by using the pressure-sensitive adhesive a was 0 ° C., and the gel fraction thereof was 40% by mass.

(Preparation Example 2) Resin (b-1)
Resin composition (1) (mixture of styrene-isoprene copolymer and styrene-isoprene-styrene copolymer, 25% by mass of structural unit derived from styrene represented by the chemical formula (1), the resin composition (1). The ratio of styrene-isoprene copolymer to the total amount is 34% by mass), 5 parts by mass of "D-135" (manufactured by Arakawa Chemical Industry Co., Ltd., polymerized rosin ester) and toluene are mixed to adjust the solid content to 40% by mass. A resin solution was obtained.

(Preparation Example 3) Resin (b-2)
Resin composition (2) (mixture of styrene-isoprene copolymer and styrene-isoprene-styrene copolymer, 25% by mass of structural unit derived from styrene represented by the chemical formula (1), the resin composition (2). The ratio of styrene-isoprene copolymer to the total amount is 17% by mass), 5 parts by mass of "D-135" (manufactured by Arakawa Chemical Industry Co., Ltd., polymerized rosin ester) and toluene are mixed to adjust the solid content to 40% by mass. A resin solution was obtained.

(Preparation Example 4) Resin (b-3)
Resin composition (3) (mixture of styrene-isoprene copolymer and styrene-isoprene-styrene copolymer, 25% by mass of structural unit derived from styrene represented by the chemical formula (1), the resin composition (3). The ratio of styrene-isoprene copolymer to the total amount is 67% by mass), 5 parts by mass of "D-135" (manufactured by Arakawa Chemical Industry Co., Ltd., polymerized rosin ester) and toluene are mixed to adjust the solid content to 40% by mass. A resin solution was obtained.

(Preparation Example 5) Resin (b-4)
Resin composition (1) (mixture of styrene-isoprene copolymer and styrene-isoprene-styrene copolymer, 25% by mass of structural unit derived from styrene represented by the chemical formula (1), the resin composition (1). The ratio of styrene-isoprene copolymer to the total amount is 34% by mass), 15 parts by mass of "D-135" (manufactured by Arakawa Chemical Industry Co., Ltd., polymerized rosin ester) and toluene are mixed to adjust the solid content to 40% by mass. A resin solution was obtained.

(Preparation Example 6) Resin (b-5)
Resin composition (4) (mixture of polymethylmethacrylate-butylpolyacrylate-polymethylmethacrylate copolymer, structural unit of polymethylmethacrylate 25% by mass) and "D-135" (Arakawa Chemical Industry Co., Ltd.) 5 parts by mass of (polymerized rosin ester manufactured by the company) and toluene were mixed to obtain a resin solution adjusted to have a solid content of 40% by mass.

(Preparation Example 6) Resin (b-6)
Resin composition (5) (mixture of polymethyl methacrylate-butyl polyacrylate-polymethyl methacrylate copolymer, structural unit of polymethyl methacrylate 12% by mass) and "D-135" (Arakawa Chemical Industry Co., Ltd.) 5 parts by mass of (polymerized rosin ester manufactured by the company) and toluene were mixed to obtain a resin solution adjusted to have a solid content of 40% by mass.

(Example 1)
A resin layer (b-1) is applied to "PET 50 x 1J0" (manufactured by Nippa Corporation, a peeling liner having a silicone-based peeling surface on the surface of a 50 μm polyester film) using a comma coater, and the temperature is 5 ° C. After drying for a minute to obtain a resin layer b-1 having a thickness of 50 μm, a foam A-1 (PureCell 010 manufactured by Inoac Corporation, a thickness of 100 μm, and a 25% compressive strength of 0.05 MPa) is an acrylic resin type. It was bonded using a continuous cell foam) and a laminator. Next, the pressure-sensitive adhesive a was dot-printed on "PET50 x 1J0" (manufactured by Nippa Corporation, a peeling liner having a silicone-based peeling surface on the surface of a 50 μm polyester film) using a gravure coater, and the temperature was 100 ° C. By drying for 1 minute in the above, an island-shaped adhesive portion having a substantially diamond shape and a thickness of 4 μm shown in FIG. 1 was obtained. The distance between the arbitrary adhesive portion and the adhesive portion in the vicinity of the adhesive portion was 0.1 mm. Next, after peeling off the release liner surface of the laminate of the foam layer (A) and the resin layer (B), the adjusted adhesive portion (C) is attached to the resin layer (B) surface, and then 40. By curing at ° C. for 2 days, an adhesive tape in which the foam layer (A), the resin layer (B) and the adhesive portion (C) were laminated was obtained.

(Examples 2 to 9 and Comparative Example 2)
An adhesive tape was produced in the same manner as in Example 1 except that the type of the resin layer (B), the thickness of the resin layer (B), and the shape of the adhesive portion (C) were changed to those shown in Table 1. did.

(Comparative Example 1)
The adhesive a is dot-printed on "PET 50 x 1J0" (manufactured by Nippa Corporation, a peeling liner having a silicone-based peeling surface on the surface of a 50 μm polyester film) using a gravure coater, and the pressure-sensitive adhesive a is dot-printed at 100 ° C. for 1 minute. By drying, an island-shaped adhesive portion (C) having a substantially rhombus shape and a thickness of 2 μm shown in FIG. 1 was obtained. Of the adhesive portion (C), the distance between the arbitrary adhesive portion and the adhesive portion (C) close to the arbitrary adhesive portion was 0.1 mm. Next, a 12 μm polyester film was laminated and attached with a laminator at a linear pressure of 3 N / mm. This was cured at 40 ° C. for two days to obtain a dot adhesive film. Next, the foam layer (A) was provided on the 4 μm polyester film of this dot adhesive film by the following method.

90 parts by mass of the polyether polyol "GP-3000" manufactured by Sanyo Kasei Kogyo Co., Ltd., 10 parts by mass of the polyether polyol "GP-600" manufactured by Sanyo Kasei Co., Ltd., 0.1 parts by mass of the catalyst "Stanas Octate" manufactured by Johoku Chemical Industry Co., Ltd. The mixture was prepared by mixing and stirring parts by mass and 5 parts by mass of the foaming agent. Then, the above-mentioned mixture and MDI "Coronate 1130" manufactured by Nippon Polyurethane Industry Co., Ltd. having an isocyanate index of 1 were put into a chamber arranged in an oak mixer. At the same time, nitrogen gas was injected so that the density of the foam layer was 300 kg / m ^3.

The components were then stirred in the chamber to prepare a foamed gas-liquid mixture. Then, this gas-liquid mixture is supplied onto a 4 μm polyester film of the dot adhesive film delivered at a rate of 5 m / min, and peeled off from above the surface of the flowing gas-liquid mixture at the same speed as the dot adhesive film. Paper was supplied and adjusted to a thickness of 100 μm with a roll coater to form an uncured layer composed of a gas-liquid mixture.

Then, the laminate composed of the dot adhesive film, the uncured layer and the release paper was placed in a heating furnace at 160 ° C. by a far-infrared heater and heated for 1 minute. Next, the release paper was peeled off from the laminate to obtain an adhesive tape in which the dot adhesive film and the foam layer (A-2) were bonded.

[Breaking point stress, breaking point elongation, 100% elongation stress of adhesive tape and resin layer (B)]
The breaking point stress, breaking point elongation, and 100% elongation stress of the adhesive tape are obtained by punching the adhesive tape into a dumbbell shape with a marked line length of 20 mm and a width of 10 mm, and tencilon tension under the conditions of measurement atmosphere of 23 ° C. and 50% RH. The measurement was carried out by pulling in the length direction at a tensile speed of 300 mm / min using a testing machine.

[Storage modulus of resin layer (B) G']
For the storage elastic modulus G'of the resin layer (B) in the present invention, a parallel plate having a diameter of 7.9 mm is attached to a viscoelasticity tester Ares 2 kSTD manufactured by Leometrics Co., Ltd. using an adhesive that is laminated to a thickness of 2 mm as a test piece. , It is a value measured at 60 ° C. with a test piece sandwiched at a frequency of 1 Hz.

(Evaluation of ease of bubble removal 1)
The adhesive tapes obtained in Examples and Comparative Examples were cut into a length of 50 mm and a width of 100 mm, the release liner was peeled off, and a glass plate having a length of 70 mm and a width of 150 mm was placed on the surface of the adhesive portion under an atmosphere of 23 ° C. and 50% RH. A temporary adhesive was obtained by placing the glass plate and leaving it to stand for 5 seconds with a load of 5 N on the glass plate.

Next, after inverting the temporary attachment, a laminate was obtained by pressurizing them by reciprocating a 2 kg roller once from the surface on the adhesive tape side.

Ten of the laminated bodies were produced by the above method. Whether or not there were air bubbles between the adhesive tape and the glass plate was confirmed by visually observing ^{the swelling of the adhesive tape (10 mm 2 or more).} The ease with which the bubbles escaped was evaluated based on the number of laminates for which the presence of bubbles could not be confirmed by the method.
⊚: The number of laminated bodies in which the presence of air bubbles could be confirmed was 0.
◯: The number of laminated bodies in which the presence of air bubbles could be confirmed was 1 or 2.
X: The number of laminated bodies in which the presence of air bubbles can be confirmed is 7 or more.

(Evaluation of ease of bubble removal 2)
The adhesive tapes obtained in Examples and Comparative Examples were left at 40 ° C. for 2 weeks, then cut into a length of 50 mm × a width of 100 mm, the release liner was peeled off, and the adhesive portion (C) was subjected to an atmosphere of 23 ° C. and 50% RH. ), A glass plate having a length of 70 mm and a width of 150 mm was placed on the surface of the glass plate, and the glass plate was left to stand for 5 seconds with a load of 5 N to obtain a temporary adhesive.

Next, after inverting the temporary attachment, a laminate was obtained by pressurizing them by reciprocating a 2 kg roller once from the surface on the adhesive tape side.

Ten of the laminated bodies were produced by the above method. Whether or not there were air bubbles between the adhesive tape and the glass plate was confirmed by visually observing ^{the swelling of the adhesive tape (10 mm 2 or more).} The ease with which the bubbles escaped was evaluated based on the number of laminates for which the presence of bubbles could not be confirmed by the method.
⊚: The number of laminated bodies in which the presence of air bubbles could be confirmed was 0.
◯: The number of laminated bodies in which the presence of air bubbles could be confirmed was 1 or 2.
X: The number of laminated bodies in which the presence of air bubbles can be confirmed is 7 or more.

[Evaluation of flow path obstruction of adhesive tape]
Evaluation of Ease of Bubble Escape After leaving the sample prepared in 1 at 23 ° C for 24 hours, observe it from the glass plate side using an optical microscope (50 times, field of view 6 mm × 6 mm), and based on the following evaluation criteria. Evaluated. In the above observation, if an air layer is present between the test piece and the glass plate, it is observed to be white depending on the printed shape of the pressure-sensitive adhesive a. In the following evaluation criteria, these air layers were evaluated as "channels through which air can pass". The "area ratio" was calculated from "the area of the flow path through which air can pass / the area of the observed test piece".
⊚: The area ratio of the flow path through which air can pass between the test piece and the glass plate was less than 5%.
◯: The area ratio of the flow path through which air can pass between the test piece and the glass plate was 5% or more and 10% or less.
Δ: The area ratio of the flow path through which air can pass between the test piece and the glass plate was 10% or more and 30% or less.
X: The area ratio of the flow path through which air can pass between the test piece and the glass plate was 30% or more.

[Removability]
The adhesive tape having a width of 10 mm and a length of 60 mm is attached to a clean and smooth surface stainless steel plate with a gripper having a length of 10 mm and a length of 10 mm protruding, and then pressurized by a roller once back and forth while applying a load of 2 kg. Was used as a test piece. After application, the adhesive tape was left to stand in an atmosphere of 23 ° C. and 50% RH for 3 days, and the gripper portion of the adhesive tape was stretched by hand in the horizontal direction of the adhesive tape at a speed of about 300 mm / min at 23 ° C. and 50% RH.
Of the three tests, the degree of adhesive tape breakage and adhesive residue on the adherend after the adhesive tape was peeled off was visually evaluated according to the following criteria.
⊚: The tape was peeled off three times without breaking.
◯: The tape was peeled off twice without breaking.
X: The adhesive tape cannot be peeled off. Or, the tape was cut more than once.

1 Foam layer 2 Adhesive part 3 Adhesive tape

Claims (15)

A resin layer (B) is provided on at least one surface of the foam layer (A), and two or more adhesive portions (on the surface (a) side of the resin layer (B) opposite to the foam layer (A). An adhesive tape having C), in which a region having no adhesive portion (C) exists between the two or more adhesive portions (C), and the region leads to an end portion of the adhesive tape. An adhesive tape having a breaking point elongation of 500 to 3000% and a breaking point stress of 3.0 to 30.0 MPa. The adhesive tape according to claim 1, wherein the stress at 100% elongation of the resin layer (B) is 0.3 to 3.0 MPa. The adhesive tape according to claim 1 or 2, wherein the resin layer (B) has a storage elastic modulus G'at 60 ° C. of 0.2 to 2.0 MPa. The adhesive tape according to any one of claims 1 to 3, wherein the resin layer (B) contains a vinyl aromatic block copolymer or an acrylic block copolymer. The adhesive tape according to any one of claims 1 to 4, wherein the resin layer (B) contains a pressure-imparting resin. The adhesive tape according to any one of claims 1 to 5, wherein the vinyl aromatic block copolymer is a block copolymer of an aromatic vinyl compound and a conjugated diene compound. The adhesive tape according to any one of claims 1 to 6, wherein the thickness of the resin layer (B) is 10 to 200 μm. The adhesive tape according to any one of claims 1 to 7, wherein the thickness of the resin layer (B) is thicker than the thickness of the adhesive portion (C). The adhesive tape according to any one of claims 1 to 8, which has a release liner (D) having a thickness of 25 μm to 125 μm on a surface in contact with the adhesive portion (C). When the adhesive portion (C) is observed from the surface (a) side of the resin layer (B) opposite to the foam layer (A), the shape of the adhesive portion (C) is substantially circular or substantially square. The adhesive tape according to any one of claims 1 to 9, which has a shape or a substantially hexagonal shape. Claims 1 to 1 in which the distance between an arbitrary adhesive portion (c1) selected from the two or more adhesive portions (C) and an adhesive portion (c2) close to the adhesive portion (c1) is 0.5 mm or less. The adhesive tape according to any one of 10. Claims 1 to 11 in which the ratio of the region having the adhesive portion (C) to the area of the surface (a) of the resin layer (B) opposite to the foam layer (A) is 10% to 99%. The adhesive tape according to any one of the above. The adhesive tape according to any one of claims 1 to 12, wherein 10 to 1,000,000 adhesive portions (C) are present in the range of 5 cm in the flow direction and 5 cm in the width direction of the adhesive tape. The adhesive tape according to any one of claims 1 to 13, wherein the foam layer (A) is a polyurethane-based foam layer or an acrylic-based foam layer. A display device characterized in that the adhesive tape according to any one of claims 1 to 14 is provided on the non-display surface side of the display.

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