JP2020117708A - Adhesive tape, and adhesive tape roll - Google Patents

Abstract

To provide an adhesive tape capable of suppressing rewinding defect from a roll after stored for a long period while suppressing peel-off and tunneling of a release film, high in release performance of the release film, and furthermore hard to generate winding deviation, and an adhesive tape roll composed of the adhesive tape.SOLUTION: The adhesive tape is a long sized adhesive tape 3 including a substrate 4, an adhesive layer 5, and a release film 6 where in an edge part of the adhesive tape, the length in a width direction of the release film is longer than a length in a width direction of the substrate by 0.1 mm or more and 50 mm or less, the length in a width direction of the adhesive layer is longer than a length in a width direction of the substrate by 0.7 mm or less, the peel force of a face of the release film in contact with the adhesive layer is 0.03-10 N/25 mm, the contact angle to water of a face of the release film opposite to a face in contact with the adhesive layer is 85-113°, and the bending resistance of the release film is 30 mm or more and 150 mm or less.SELECTED DRAWING: Figure 2

Description

The present invention relates to an adhesive tape and an adhesive tape roll including the adhesive tape.

Adhesive tapes are used in various industrial fields because they can be easily joined. In the construction field, temporary fixing of curing sheets, bonding of interior materials, etc., in the automobile field, fixing of interior parts such as seats and sensors, fixing of exterior parts such as side moldings and side visors, and module assembly in the electric and electronic fields, Adhesive tape is used to attach the module to the housing. More specifically, for example, an adhesive tape is widely used as a surface protection tape for temporarily protecting the surface of a member such as an optical device, a metal plate, a coated metal plate, a resin plate, and a glass plate ( For example, Patent Documents 1 to 3).

Japanese Patent Laid-Open No. 1-129085 JP, 6-1958, A JP-A-8-12952

Usually, the pressure-sensitive adhesive tape is shipped in the form of a pressure-sensitive adhesive tape roll that is manufactured and then wound into a roll, and is appropriately rewound from the pressure-sensitive adhesive tape roll and cut into an appropriate shape for use. However, the conventional pressure-sensitive adhesive tape roll may not be able to be rewound from the roll when it is stored for a long period of time, or a large force may be required for rewinding. FIG. 1 shows an example of a conventional adhesive tape roll. When the conventional pressure-sensitive adhesive tape 1 is wound in a roll shape, stress is applied in the core direction of the roll, so that the pressure-sensitive adhesive 2 of the pressure-sensitive adhesive tape may squeeze out to the side surface of the roll when stored for a long period of time. The protruding adhesive 2 adheres to the other protruding adhesive 2, so that the adhesive tape cannot be rewound from the roll or a large force is required for rewinding. In particular, when the adhesive tape is stored at a high temperature, the above-mentioned phenomenon may occur easily because the adhesive is more likely to stick out to the side surface.

On the other hand, when an adhesive tape is used to protect the surface of an electronic component or the like, the adhesive tape is required to have the ability to follow the irregularities of the adherend. For example, in order to make the adhesive tape follow the high unevenness of the adherend, it is necessary to thicken the adhesive layer of the adhesive tape. Since the pressure-sensitive adhesive will stick out to the side more than the normal pressure-sensitive adhesive tape, it may be more difficult to rewind from the roll.

For such a problem of unwinding, by sticking a release film having a width wider than the width of the base material and the pressure-sensitive adhesive layer to the pressure-sensitive adhesive layer and rolling it, adhesion between the pressure-sensitive adhesive layers protruding Methods have been proposed to prevent this. However, it is difficult to completely suppress the rewinding failure due to the protrusion of the pressure-sensitive adhesive by simply increasing the width of the release film, and widening the width of the release film causes a new problem of tunneling.

Tunneling is a phenomenon in which peeling and floating occur between the release film and the pressure-sensitive adhesive layer, and when tunneling occurs, the pressure-sensitive adhesive layer surface is deformed to generate steps and roughness. Therefore, when an adhesive tape that has undergone tunneling is attached to an adherend, uneven adhesion is likely to occur, and uneven curing tends to occur when the adhesive layer is a curable type. When the width of the release film is widened, a large force is likely to be applied to the end portion of the pressure-sensitive adhesive layer in the width direction, so that tunneling is likely to occur. A method of increasing the adhesive force between the pressure-sensitive adhesive layer and the release film is effective for suppressing tunneling, but if the adhesive force is increased, the release film becomes difficult to peel off and the handling property is impaired.

In view of the above problems, the present invention can suppress the rewinding failure from the roll when stored for a long time, the peeling performance of the release film is high while suppressing the peeling and the tunneling of the release film, and the winding deviation is also caused. An object of the present invention is to provide an adhesive tape that is unlikely to occur and an adhesive tape roll made of the adhesive tape.

The present invention is a long-sized pressure-sensitive adhesive tape having a substrate, a pressure-sensitive adhesive layer and a release film, wherein the length in the width direction of the release film is the width of the substrate at the end of the pressure-sensitive adhesive tape. 0.1 mm or more and 50 mm or less longer than the length in the direction, the length in the width direction of the pressure-sensitive adhesive layer is 0.7 mm or less longer than the length in the width direction of the base material, and contacts the pressure-sensitive adhesive layer of the release film. The side surface has a peeling force of 0.03 to 10 N/25 mm, the surface of the release film on the side opposite to the surface in contact with the pressure-sensitive adhesive layer has a contact angle with water of 85 to 113°, and the mold release It is an adhesive tape having a bending resistance of 30 mm or more and 150 mm or less.
Hereinafter, the present invention will be described in detail.

The adhesive tape of the present invention is a long adhesive tape having a substrate, an adhesive layer and a release film.
Here, the elongated shape refers to a shape having long sides long enough to form a roll-shaped body or a shape rewound from the roll-shaped body. In this specification, the direction orthogonal to the long side direction is referred to as the width direction. In addition, a roll-shaped body that is rewound and cut is also included in a long shape. When the adhesive tape is rewound from a roll and cut, regardless of the size after cutting, the side that hits the long direction before cutting is the long side. In a preferred embodiment, the long side before cutting corresponds to the long side of the adhesive tape.

The base material is not particularly limited, and examples thereof include a polyolefin resin film, a polyester resin film, an ethylene-vinyl acetate copolymer, a modified olefin resin film, a polyvinyl chloride resin film, a polyurethane resin film, a cycloolefin polymer. Examples thereof include a resin film, an acrylic resin film, a polycarbonate film, an ABS (acrylonitrile-butadiene-styrene) resin film, a polyamide film, a polyurethane film and a polyimide film. Examples of the polyolefin resin film include polyethylene film and polypropylene film. Examples of the polyester resin film include polyethylene terephthalate (PET) film and polyethylene naphthalate (PEN) film. Examples of the modified olefin resin film include ethylene-acrylic acid ester copolymers. When the present invention is used as a surface protective film, a substrate having a high elastic modulus is suitable because it can exhibit higher peelability. The storage elastic modulus (G') of the preferable base material is 2 GPa or more and 10 GPa or less. When it is desired to confirm the state of the adherend through the adhesive tape, a substrate having a relatively low haze value (haze is preferably 2 or less, more preferably 1.5 or less) is suitable.

The thickness of the substrate is not particularly limited, but the preferred lower limit is 10 μm and the preferred upper limit is 250 μm. When the thickness of the base material is within this range, the pressure-sensitive adhesive tape has appropriate elasticity and excellent handleability. From the same viewpoint, the more preferable lower limit of the thickness of the base material is 12 μm, the more preferable upper limit thereof is 230 μm, the still more preferable lower limit thereof is 20 μm, the further preferable upper limit thereof is 200 μm, the still more preferable lower limit thereof is 25 μm, and the still more preferable upper limit thereof is 188 μm, particularly A preferred lower limit is 30 μm, and a particularly preferred upper limit is 180 μm.

The length of the base material in the width direction is preferably 25 mm or more, more preferably 30 mm or more, still more preferably 35 mm or more, preferably 2000 mm or less, more preferably 1500 mm or less, still more preferably 1000 mm or less. When the width of the base material is within the above range, unwinding failure from the roll, peeling of the release film, tunneling and winding misalignment can be further suppressed.

The pressure-sensitive adhesive forming the pressure-sensitive adhesive layer is not particularly limited, and may be a curable pressure-sensitive adhesive or a non-curable pressure-sensitive adhesive. Of these, a curable pressure-sensitive adhesive is preferable because the pressure-sensitive adhesive can be easily peeled off by stimulating the pressure-sensitive adhesive to cure when the pressure-sensitive adhesive tape becomes unnecessary.

Examples of the curable pressure-sensitive adhesive include a photo-curable pressure-sensitive adhesive that is crosslinked and cured by light irradiation, and a thermosetting pressure-sensitive adhesive that is crosslinked and cured by heating.
Examples of the photocurable pressure-sensitive adhesive include a photocurable pressure-sensitive adhesive containing a polymerizable polymer as a main component and a photopolymerization initiator.
Examples of the thermosetting adhesive include a thermosetting adhesive containing a polymerizable polymer as a main component and a thermopolymerization initiator.

As the above-mentioned polymerizable polymer, for example, a (meth)acrylic polymer having a functional group in the molecule (hereinafter, referred to as a functional group-containing (meth)acrylic polymer) is synthesized in advance and reacted with the above-mentioned functional group in the molecule. It can be obtained by reacting a compound having a functional group with a radical-polymerizable unsaturated bond (hereinafter referred to as a functional group-containing unsaturated compound).

The functional group-containing (meth)acrylic polymer has as a main monomer an acrylic acid alkyl ester and/or a methacrylic acid alkyl ester having a carbon number of an alkyl group in the range of 2 to 18, and a functional group-containing monomer, Further, it can be obtained by copolymerizing, if necessary, these with another modifying monomer copolymerizable with them by a conventional method. The weight average molecular weight of the functional group-containing (meth)acrylic polymer is usually about 200,000 to 2,000,000.

Examples of the functional group-containing monomer include carboxyl group-containing monomers such as acrylic acid and methacrylic acid, hydroxyl group-containing monomers such as hydroxyethyl acrylate and hydroxyethyl methacrylate, and epoxy such as glycidyl acrylate and glycidyl methacrylate. Group-containing monomers are mentioned. Further, isocyanate group-containing monomers such as isocyanate ethyl acrylate and isocyanate ethyl methacrylate, amino group-containing monomers such as aminoethyl acrylate and aminoethyl methacrylate, and the like are also included.
In the present invention, from the viewpoint of improving heat resistance, acrylic acid and/or methacrylic acid may be contained as the functional group-containing monomer.

Examples of the other copolymerizable modifying monomer include various monomers used for general (meth)acrylic polymers such as vinyl acetate, acrylonitrile, and styrene.

The functional group-containing unsaturated compound to be reacted with the functional group-containing (meth)acrylic polymer is selected from the same functional group-containing monomers as described above according to the functional group of the functional group-containing (meth)acrylic polymer. can do. For example, when the functional group of the functional group-containing (meth)acrylic polymer is a carboxyl group, an epoxy group-containing monomer or an isocyanate group-containing monomer is used. When the functional group is a hydroxyl group, an isocyanate group-containing monomer is used. When the functional group is an epoxy group, a carboxyl group-containing monomer or an amide group-containing monomer such as acrylamide is used. When the functional group is an amino group, an epoxy group-containing monomer is used.

Examples of the photopolymerization initiator include those activated by irradiation with light having a wavelength of 250 to 800 nm. Examples of such a photopolymerization initiator include acetophenone derivative compounds such as methoxyacetophenone, benzoin propyl ether, benzoin ether compounds such as benzoin isobutyl ether, benzyl dimethyl ketal, ketal derivative compounds such as acetophenone diethyl ketal, and the like, Examples thereof include phosphine oxide derivative compounds. Further, a bis(η5-cyclopentadienyl)titanocene derivative compound, benzophenone, Michler's ketone, chlorothioxanthone, todecylthioxanthone, dimethylthioxanthone, diethylthioxanthone, α-hydroxycyclohexylphenyl ketone, 2-hydroxymethylphenylpropane and the like can be mentioned. These photopolymerization initiators may be used alone or in combination of two or more kinds.

Examples of the above-mentioned thermal polymerization initiator include those that decompose by heat and generate active radicals that initiate polymerization and curing. Specifically, for example, dicumyl peroxide, di-t-butyl peroxide, t-butyl peroxybenzole, t-butyl hydroperoxide, benzoyl peroxide, cumene hydroperoxide, diisopropylbenzene hydroperoxide, Paramenthane hydroperoxide, di-t-butyl peroxide, etc. are mentioned.
Of these thermal polymerization initiators, commercially available ones are not particularly limited, but for example, perbutyl D, perbutyl H, perbutyl P, perpenta H (all of which are manufactured by NOF CORPORATION) and the like are preferable. These thermal polymerization initiators may be used alone or in combination of two or more kinds.

It is preferable that the photocurable pressure-sensitive adhesive or the thermosetting pressure-sensitive adhesive further contains a radically polymerizable polyfunctional oligomer or monomer. By containing a radically polymerizable polyfunctional oligomer or monomer, photocurability and thermosetting property are improved.
The polyfunctional oligomer or monomer preferably has a molecular weight of 10,000 or less, and more preferably has a molecular weight of 5,000 or less so that three-dimensional reticulation of the pressure-sensitive adhesive layer can be efficiently performed by heating or irradiation with light. Moreover, the number of radically polymerizable unsaturated bonds in the molecule is 2 to 20.

The polyfunctional oligomer or monomer is, for example, trimethylolpropane triacrylate, tetramethylolmethane tetraacrylate, pentaerythritol triacrylate, pentaerythritol tetraacrylate, dipentaerythritol monohydroxypentaacrylate, dipentaerythritol hexaacrylate or a methacrylate similar to the above. And the like. Other examples include 1,4-butylene glycol diacrylate, 1,6-hexanediol diacrylate, polyethylene glycol diacrylate, commercially available oligoester acrylate, and the same methacrylates as described above. These polyfunctional oligomers or monomers may be used alone or in combination of two or more.

The curable pressure-sensitive adhesive may contain a silicone compound having a functional group capable of crosslinking with the curable pressure-sensitive adhesive. By blending the silicone compound, the silicone compound bleeds out to the adherend interface at the time of peeling and the peeling can be facilitated. Further, since the silicone compound has a functional group capable of crosslinking with the curable pressure-sensitive adhesive, it is chemically reacted with the curable pressure-sensitive adhesive by light irradiation or heating and is incorporated into the curable pressure-sensitive adhesive, Silicone compound does not adhere to the adherend to contaminate it. Furthermore, by blending a silicone compound, the effect of preventing adhesive residue on the adherend is also exerted.

The pressure-sensitive adhesive layer may further contain an inorganic filler such as fumed silica. By incorporating an inorganic filler, the cohesive force of the pressure-sensitive adhesive layer increases. Therefore, when the pressure-sensitive adhesive layer contains an inorganic filler such as fumed silica, when the pressure-sensitive adhesive tape becomes unnecessary, the pressure-sensitive adhesive tape can be more easily peeled from the adherend without leaving any adhesive residue.

The above-mentioned pressure-sensitive adhesive layer appropriately contains various polyfunctional compounds to be mixed with general pressure-sensitive adhesives such as an isocyanate compound, a melamine compound and an epoxy compound, if desired, for the purpose of adjusting the cohesive force as a pressure-sensitive adhesive. Good.
The pressure-sensitive adhesive layer may contain known additives such as a plasticizer, a resin, a surfactant, a wax and a fine particle filler. The above additives may be used alone or in combination of two or more.

The pressure-sensitive adhesive layer preferably has a gel fraction of 1% or more and 65% or less.
When the gel fraction of the pressure-sensitive adhesive layer is at least the above lower limit, it is possible to further suppress the protrusion of the pressure-sensitive adhesive when it is formed into a tape roll, and thus it is possible to further suppress unwinding failure. Further, when the gel fraction of the pressure-sensitive adhesive layer is at most the above upper limit, it is possible to suppress adhesive residue while exhibiting an appropriate pressure-sensitive adhesive force, and it is sufficient even when used for an adherend with large irregularities. Can follow. From the same viewpoint, the more preferable lower limit of the gel fraction of the pressure-sensitive adhesive layer is 2%, the more preferable lower limit thereof is 3%, the more preferable upper limit thereof is 60%, and the still more preferable upper limit thereof is 55%. The gel fraction can be measured by the following method.
Only 0.1 g of the adhesive layer of the adhesive tape is scraped off, immersed in 50 ml of ethyl acetate, and shaken with a shaker at a temperature of 23° C. and 200 rpm for 24 hours (hereinafter, the scraped off adhesive layer That is referred to as the adhesive composition). After shaking, ethyl acetate and a swollen pressure-sensitive adhesive composition that absorbs ethyl acetate are separated using a metal mesh (opening #200 mesh). The pressure-sensitive adhesive composition after separation is dried at 110° C. for 1 hour. The weight of the pressure-sensitive adhesive composition containing the dried metal mesh is measured, and the gel fraction of the pressure-sensitive adhesive layer is calculated using the following formula. When the pressure-sensitive adhesive layer is composed of a curable pressure-sensitive adhesive, the gel fraction means the gel fraction before curing.
Gel fraction (% by weight)=100×(W ₁ −W ₂ )/W ₀
(W ₀ : weight of initial pressure-sensitive adhesive composition, W ₁ : weight of pressure-sensitive adhesive composition containing dried metal mesh, W ₂ : initial weight of metal mesh)

The adhesive layer preferably has a storage elastic modulus G′ at 23° C. of 5.0×10 ³ Pa or more and 2.0×10 ⁸ Pa or less.
When the storage elastic modulus of the pressure-sensitive adhesive layer is within the above range, it is possible to suppress adhesive residue while exhibiting an appropriate pressure-sensitive adhesive force, and sufficiently follow up even when used on an adherend with large irregularities. be able to. Further, the protrusion of the pressure-sensitive adhesive layer can be easily adjusted within the range described below. From the same viewpoint, a more preferable lower limit of the storage elastic modulus of the pressure-sensitive adhesive layer is 0.1×10 ⁵ Pa, a still more preferable lower limit is 0.2×10 ⁵ Pa, and a more preferable upper limit is 200×10 ⁵ Pa, and further preferable. The upper limit is 20×10 ⁵ Pa. The storage elastic modulus is measured by a method according to JIS K 7244 using a dynamic viscoelasticity measuring device (for example, DVA-200, manufactured by IT Measurement and Control Co., Ltd.) in a tension/compression mode and an angular frequency of 1 Hz. can do.

The pressure-sensitive adhesive layer preferably has a thickness of 100 μm or more, more preferably 150 μm or more, and further preferably 200 μm or more.
When the thickness of the pressure-sensitive adhesive layer is equal to or more than the above lower limit, the pressure-sensitive adhesive tape can be reliably adhered to the irregularities even when the adherend has large irregularities, so that the adhesive tape can be reliably adhered. Can sufficiently protect the body. When a conventional pressure-sensitive adhesive tape is formed into such a roll by forming such a thick pressure-sensitive adhesive layer, the pressure-sensitive adhesive layer tends to stick out to the side surface of the roll when stored for a long period of time, and unwinding failure of the roll is likely to occur. The adhesive tape of (1) is less likely to cause unwinding failure even when a thick adhesive layer is formed. The upper limit of the thickness of the pressure-sensitive adhesive layer is not particularly limited, but the preferable upper limit is 500 μm, the more preferable upper limit is 480 μm, and the still more preferable upper limit is 450 μm.

The release film is laminated on the surface of the pressure-sensitive adhesive layer that is in contact with the adherend, and has the role of reducing the charge generated when the roll-shaped pressure-sensitive adhesive tape is rewound and making it difficult to attract foreign substances in the environment. Further, by stacking the release film, the adhesive surface does not come into contact with the transport roller during manufacturing, so that the smoothness of the adhesive surface can be maintained and the adhesion of foreign matter can be suppressed.

In the pressure-sensitive adhesive tape of the present invention, at the end of the pressure-sensitive adhesive tape, the length in the width direction of the release film is 0.1 mm or more and 50 mm or less than the length in the width direction of the base material (hereinafter, this length This is also referred to as the protrusion width of the release film with respect to the substrate).
At the end in the width direction, the width of the release film is longer than the width of the base material by the above range, that is, the release film protrudes in the width direction from the base material and is stored for a long time while suppressing tunneling. It is possible to suppress the rewinding failure at the time. If the protrusion width of the release film to the base material is less than 0.1 mm, the adhesion between the pressure-sensitive adhesive layers protruding to the side cannot be suppressed, and if the protrusion width of the release film to the base material exceeds 50 mm, tunneling occurs. Easier to do. From the same viewpoint, the preferable lower limit of the protrusion width of the release film with respect to the substrate is 0.3 mm, the more preferable lower limit is 0.5 mm, the preferable upper limit is 30 mm, and the more preferable upper limit is 20 mm. The protruding width of the release film with respect to the base material is enlarged by a microscope (digital microscope VHX-6000, manufactured by KEYENCE CORPORATION, or its equivalent) around the end portion in the width direction of the adhesive tape, and the attached image. It can be measured by using processing software. More specifically, it refers to a value obtained by measuring the length of the release film protruding from the base material at the widthwise end portion of the base material in the long adhesive tape and averaging the measured values. The measurement is made by dividing the lengthwise direction of the long adhesive tape into five equal parts, and the measurement is carried out at a total of 6 points, the start point and the end point of each section. The protruding width of the release film with respect to the base material may satisfy the above range at least at one end of the pressure-sensitive adhesive tape, but from the viewpoint of further suppression of unwinding failure during tunneling and long-term storage, It is preferable that both ends of the pressure-sensitive adhesive tape satisfy the range of the protruding width of the release film.

In the pressure-sensitive adhesive tape of the present invention, the length in the width direction of the release film is preferably 0 mm or more and 50 mm or less longer than the length in the width direction of the pressure-sensitive adhesive layer (hereinafter, this length is referred to as the pressure-sensitive adhesive of the release film. It is also called the width of protrusion to the agent layer). At the end in the width direction, the width of the release film is 0 mm or more longer than the width of the pressure-sensitive adhesive layer, that is, the release film has the same length as the pressure-sensitive adhesive layer, or protrudes in the width direction from the pressure-sensitive adhesive layer. Thus, it is possible to further suppress the unwinding failure during long-term storage while suppressing tunneling. Further, when the protrusion width of the release film satisfies the above range, the adhesion of the pressure-sensitive adhesive layers protruding to the side surface can be further suppressed. Furthermore, since the protruding width of the release film with respect to the pressure-sensitive adhesive layer is 50 mm or less, it is possible to suppress unwinding defects during long-term storage while suppressing tunneling. The more preferable lower limit of the protrusion width of the release film with respect to the pressure-sensitive adhesive layer is 0.001 mm, the more preferable upper limit thereof is 40 mm, and the still more preferable upper limit thereof is 30 mm. The protrusion width of the release film with respect to the pressure-sensitive adhesive layer may satisfy the above range at least at one end of the pressure-sensitive adhesive tape, but from the viewpoint of further suppressing unwinding failure during tunneling and long-term storage. It is preferable that both ends of the pressure-sensitive adhesive tape satisfy the range of the protrusion width of the release film with respect to the pressure-sensitive adhesive layer. The protrusion width of the release film with respect to the pressure-sensitive adhesive layer can be measured by the same method as the protrusion width of the release film with respect to the substrate, except that the measurement target is changed from the base material to the pressure-sensitive adhesive layer.

The length of the release film in the width direction is preferably 25 mm or more, more preferably 30 mm or more, further preferably 35 mm or more, preferably 2000 mm or less, more preferably 1500 mm or less, still more preferably 1000 mm or less. When the width of the base material is within the above range, unwinding failure from the roll, peeling of the release film, tunneling and winding misalignment can be further suppressed.

The release film has a peeling force (hereinafter, also simply referred to as a peeling force) on the surface in contact with the pressure-sensitive adhesive layer of 0.03 to 10 N/25 mm.
When the peeling force of the surface of the release film in contact with the pressure-sensitive adhesive layer is within the above range, the release film can be easily peeled off after rewinding the pressure-sensitive adhesive tape from the pressure-sensitive adhesive tape roll, and the handleability of the pressure-sensitive adhesive tape is improved. Can be improved. From the same viewpoint, a more preferable lower limit of the release force on the pressure-sensitive adhesive layer side of the release film is 0.04 N/25 mm, a still more preferable lower limit is 0.05 N/25 mm, and a particularly preferable lower limit is 0.06 N/25 mm, A more preferable upper limit is 7 N/25 mm, a still more preferable upper limit is 5 N/25 mm, and a particularly preferable upper limit is 3 N/25 mm. The peeling force of the release film on the pressure-sensitive adhesive layer side can be adjusted depending on the material of the release film and the conditions of the release treatment. The peeling force on the pressure-sensitive adhesive layer side of the release film can be measured by performing a tensile test in the 180° direction at a peeling speed of 300 mm/min according to JIS Z0237.

In the release film, the contact angle of water on the surface opposite to the surface in contact with the pressure-sensitive adhesive layer (hereinafter, also simply referred to as water) is 85 to 113°.
When the pressure-sensitive adhesive tape is made into a roll, the pressure-sensitive adhesive sticking out from the pressure-sensitive adhesive tape of the layer on the winding core side is that the surface of the release film on the side opposite to the surface in contact with the pressure-sensitive adhesive layer is 85° or more. Even when the agent layer is attached to the release film of the upper adhesive tape, it can be easily peeled off from the release film, and rewinding failure can be suppressed. Further, when the contact angle is 113° or less, slippage is less likely to occur between the release film and the base material of the adhesive tape on the winding core side, and thus roll misalignment can be suppressed. The preferable range of the contact angle is 90 to 110°. As a method of setting the contact angle to water of the surface on the side opposite to the surface in contact with the pressure-sensitive adhesive layer in the above range, a method of subjecting the surface on the side opposite to the surface in contact with the pressure-sensitive adhesive layer to a release treatment, of a release film Examples include a method of adjusting the material and the mold release treatment condition. The contact angle of water on the surface opposite to the surface in contact with the pressure-sensitive adhesive layer can be measured by a method according to JIS R3257.
More specifically, it can be measured as follows.
The release film is peeled from the adhesive tape, and the release film is cut into a width of 25 mm to prepare a test piece. The surface of the test piece that was not in contact with the pressure-sensitive adhesive layer was placed horizontally as the top surface, and 2 μL of water droplets (pure water) on the surface of the release film under the environment of room temperature 25° C. and humidity 40% according to JIS R 3257:1999. Is dripped. The angle formed by the pure water and the surface of the release film 5 seconds after the dropping was measured using a contact angle measuring device (CAM 200, CAM 200, or its equivalent), and the pressure-sensitive adhesive layer of the release film was measured. The contact angle with respect to water (contact angle with water) of the surface opposite to the surface in contact with is measured.

The release film may be subjected to a release treatment on one side or both sides, but it is preferable that the release film is subjected to a release treatment on both sides.
By subjecting both surfaces of the release film to the release treatment, the release force and the contact angle to water can be easily adjusted to the above range. The release film that has been subjected to release treatment on both sides is the method of applying the release treatment to the surface of the commercially available single-sided release film that has not been subjected to the release treatment, and the release film on both sides of the film that is the material of the release film. It can be obtained by a method of performing mold treatment.
The method of the release treatment is not particularly limited, and for example, a silicone-based release agent, a fluorine-based release agent, a long-chain alkyl-based release agent, etc. may be applied to the surface of the release film which has not been subjected to the release treatment. The method of application and the like can be mentioned.

If the release film is subjected to a release treatment only on one side, after adjusting the release film material and release treatment conditions, the release film should be stored in a state of overlapping such as rolls. Thus, the peeling force and the contact angle with respect to water can be adjusted within the above range.
The release film is often wound and stored in a roll shape until the release film is used for producing the adhesive tape. When the release film that has been subjected to a release treatment on one side is stored as a roll, the release agent on the release-treated surface of the release film has been applied to the release agent of the upper release film. May be transferred to a non-printed surface. Therefore, by adjusting the material of the release film and the release treatment condition so that the release agent is appropriately transferred, even if the release film is subjected to the release treatment only on one side, the above-mentioned release force And the contact angle with respect to water can be within the above range. However, the degree of transfer of the release agent is likely to change under various conditions such as storage conditions. Therefore, in order to ensure that the release force and the contact angle with water are met, the release agent with release treatment on both sides It is preferable to use a film.

The release film has a bending resistance of 30 mm or more and 150 mm or less.
When the release film has a bending resistance of 30 mm or more, since the release film has an appropriate rigidity, it is possible to prevent the occurrence of tunneling between the release film and the pressure-sensitive adhesive layer. When the release film has a bending resistance of 150 mm or less, the pressure-sensitive adhesive tape can be easily formed into a roll shape. From the same viewpoint, the preferable lower limit of the bending resistance of the release film is 50 mm or more, the more preferable lower limit is 70 mm or more, the preferable upper limit is less than 150 mm, and the more preferable upper limit is 130 mm or less. The bending resistance of the release film can be adjusted by the material used for the release film and the thickness of the release film. The above-mentioned bending resistance can be measured by a method based on JIS L1096.

The thickness of the release film is not particularly limited, but the preferred lower limit is 15 μm, the more preferred lower limit is 25 μm, the preferred upper limit is 188 μm, and the more preferred upper limit is 125 μm. When the thickness of the release film is within the above range, the handleability is excellent, and the bending resistance can be easily adjusted within the above range.

The material of the release film is not particularly limited as long as it can satisfy the peeling force and the contact angle to water, and examples thereof include polyesters such as polyethylene terephthalate and polyethylene naphthalate, and polyolefins such as polypropylene and polyethylene. .. Among them, polyethylene terephthalate is preferable because it is easy to control the bending resistance in addition to the peeling force and the contact angle with water.

In the pressure-sensitive adhesive tape of the present invention, the length of the pressure-sensitive adhesive layer in the width direction is 0.7 mm or less longer than the length of the pressure-sensitive adhesive layer in the width direction (hereinafter, this length is extruded from the pressure-sensitive adhesive layer to the substrate. Also called width). Since the widthwise protrusion of the adhesive layer with respect to the substrate is within the above range, even when used for an adherend with large irregularities, it is possible to sufficiently follow the irregularities and reliably protect the adherend. On the other hand, the pressure-sensitive adhesive layers protruding to the side face are hard to adhere to each other, and rewinding failure is unlikely to occur. From the same viewpoint, the preferable upper limit of the protrusion width of the pressure-sensitive adhesive layer with respect to the substrate is 0.6 mm, the more preferable upper limit is 0.5 mm, and the still more preferable upper limit is 0.4 mm. The lower limit of the protrusion width of the pressure-sensitive adhesive layer with respect to the substrate is not particularly limited, but is preferably 0.002 mm, more preferably 0.005 mm. The protrusion width of the pressure-sensitive adhesive layer with respect to the base material can be measured in the same manner as the protrusion width of the release film with respect to the base material, except that the length of the pressure-sensitive adhesive layer protruding from the base material is measured. ..

The pressure-sensitive adhesive tape of the present invention preferably has a thickness of 100 μm or more, more preferably 150 μm or more, and further preferably 200 μm or more. When the thickness of the adhesive tape of the present invention is within the above range, even when used for an adherend having large irregularities, the irregularities can be sufficiently followed to surely protect the adherend. The upper limit of the thickness of the pressure-sensitive adhesive tape is not particularly limited, but is preferably 1000 μm, more preferably 700 μm, and further preferably 500 μm from the viewpoint that wrinkles are less likely to occur due to bending deformation when passing through the transport roller during processing.

The adhesive tape of the present invention has a base material, an adhesive layer and a release film. In one embodiment of the present invention, in the above-mentioned pressure-sensitive adhesive tape, a substrate, a pressure-sensitive adhesive layer and a release film are laminated in this order. The surface of the base material facing the pressure-sensitive adhesive layer may or may not be subjected to a mold release treatment.

Here, FIG. 2 schematically shows a part of the cross section in the diameter direction of the pressure-sensitive adhesive tape of the present invention in the form of a roll. Reference numeral 3 denotes an outermost pressure-sensitive adhesive tape of the roll, and 3'and 3" denote pressure-sensitive adhesive tapes of layers on the winding core side. The pressure-sensitive adhesive layers 5'and 5" are base materials 4 by a force applied in the winding core direction. In the pressure-sensitive adhesive tape of the present invention, since the release films 6, 6', 6" protrude from the base material in the width direction, the pressure-sensitive adhesive layers 5', 5" protruding from each other are adhered to each other. Even if the protruding adhesive layers 5′ and 5″ are stuck to the release films 6 and 6′ of the outer layers, the release films 6 and 6′ are not attached to the surface on the winding core side. Since the contact angle to water is within a specific range, it can be easily peeled off, and unwinding failure during storage for a long time hardly occurs. Furthermore, by setting the contact angle of water on the surface on the winding core side within a specific range, slippage with the base material is less likely to occur and winding deviation is less likely to occur.

The method for producing the adhesive tape of the present invention is not particularly limited. For example, a curable pressure-sensitive adhesive solution is prepared by adding a polymerizable polymer, a photo- or thermal-polymerization initiator, and various additives as necessary to a solvent, and mixing them to prepare a curable or non-curable type on a substrate. Examples include a method of forming a pressure-sensitive adhesive layer by applying and drying the pressure-sensitive adhesive solution, and then laminating a release film on the pressure-sensitive adhesive layer.

The application of the pressure-sensitive adhesive tape of the present invention is not particularly limited, but it can be suitably used as a protective tape for protecting electronic components in the production of electronic components such as semiconductor wafers. Among them, the pressure-sensitive adhesive tape of the present invention is particularly suitable as a protective tape for a high-bump wafer having a high bump height, because it does not cause rewinding defects when formed into a roll even if the pressure-sensitive adhesive layer is thickened. Can be used. The bump height of the high bump wafer is not particularly limited, but is preferably 100 μm or more, more preferably 150 μm or more, and further preferably 200 μm or more. In the case of a high bump wafer having such a bump height, the effect of the present invention is greatly exerted.

The pressure-sensitive adhesive tape of the present invention can solve problems such as unwinding defects, peeling and peeling defects of release films, tunneling, and winding misalignment that occur when the pressure-sensitive adhesive tape is formed into a roll. An adhesive tape roll made of the adhesive tape of the present invention is also one aspect of the present invention. The roll width of the adhesive tape roll is not particularly limited, but is preferably 20 mm or more, more preferably 30 mm or more, and further preferably 40 mm or more. The roll width of the adhesive tape roll is preferably 1500 mm or less, more preferably 1300 mm or less, even more preferably 1100 mm or less, even more preferably 900 mm or less, particularly preferably 700 mm or less, very preferably 500 mm or less, and particularly preferably It is 300 mm or less. The method for producing an adhesive tape roll can be usually produced by winding a long adhesive tape. The diameter of the pressure-sensitive adhesive tape roll is not particularly limited, but is, for example, 5000 mm or less, particularly 3000 mm or less, particularly 1000 mm or less, and usually 25 mm or more.

The method for producing the pressure-sensitive adhesive tape roll of the present invention is not particularly limited, and it can be produced, for example, by winding the pressure-sensitive adhesive tape produced by the above-mentioned method for producing an adhesive tape around a winding core.

The application of the pressure-sensitive adhesive tape roll of the present invention is not particularly limited, but it can be preferably used as a protective tape for protecting electronic components in the production of electronic components such as semiconductor wafers. Among them, the pressure-sensitive adhesive tape roll of the present invention can be particularly suitably used as a protective tape for a high-bump wafer having a high bump height because it does not cause rewinding defects even if the pressure-sensitive adhesive layer is thickened. The bump height of the high bump wafer is not particularly limited, but when the bump height is preferably 100 μm or more, more preferably 150 μm or more, still more preferably 200 μm or more, the effect of the present invention is greatly exerted.

According to the present invention, it is possible to suppress the rewinding failure from the roll when stored for a long time, the peeling performance of the release film is high while suppressing the peeling and the tunneling of the release film, and the sticking which is less likely to cause winding deviation A tape and an adhesive tape roll made of the adhesive tape can be provided.

It is a figure showing an example of the conventional adhesive tape roll. It is the figure which showed typically a part of cross section in the diameter direction of the adhesive tape of this invention made into the roll form.

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

(Example 1)
(Production of release film)
The surface of the polyethylene terephthalate (PET) film A having a thickness of 50 μm, which has been subjected to release treatment on one side, which has not been subjected to release treatment, is subjected to corona treatment, and a solvent-based addition type silicone release agent A is applied onto the corona-treated surface to release Mold processing was performed to obtain a release film having both surfaces subjected to release processing. The following were used as the PET film A and the silicone release agent A. Further, hereinafter, the surface of the PET film that has been subjected to a mold release treatment from the beginning is also referred to as a front mold release treated surface, and the surface coated with the silicone mold release agent is referred to as a post mold release treated surface.
PET film A: manufactured by Nakamoto Pax, silicone-based PET release film, NS separator C type silicone release agent A: manufactured by Shin-Etsu Silicone, KS-3601

(Production of adhesive)
A reactor equipped with a thermometer, a stirrer, and a cooling pipe was prepared, and in the reactor, 94 parts by weight of 2-ethylhexyl acrylate as an alkyl (meth)acrylate ester and 6 parts by weight of hydroxyethyl methacrylate as a functional group-containing monomer. After adding 0.01 part by weight of lauryl mercaptan and 80 parts by weight of ethyl acetate, the reactor was heated to start reflux. Then, 0.01 parts by weight of 1,1-bis(t-hexylperoxy)-3,3,5-trimethylcyclohexane was added as a polymerization initiator into the reactor, and polymerization was initiated under reflux. It was Then, 1 and 2 hours after the initiation of the polymerization, 0.01 parts by weight of 1,1-bis(t-hexylperoxy)-3,3,5-trimethylcyclohexane was added to each of them, and the polymerization was further initiated. After 4 hours, 0.05 part by weight of t-hexyl peroxypivalate was added to continue the polymerization reaction. Then, 8 hours after the initiation of the polymerization, an ethyl acetate solution of a functional group-containing (meth)acrylic polymer having a solid content of 55% by weight and a weight average molecular weight of 600,000 was obtained.
Reaction was carried out by adding 3.5 parts by weight of 2-isocyanatoethyl methacrylate as a functional group-containing unsaturated compound to 100 parts by weight of the resin solid content of the ethyl acetate solution containing the obtained functional group-containing (meth)acrylic polymer. Then, a polymerizable polymer was obtained. Then, 1 part by weight of a photopolymerization initiator and 0.15 part by weight of an isocyanate curing agent were mixed with 100 parts by weight of a resin solid content of the obtained ethyl acetate solution of a polymerizable polymer, and an ethyl acetate solution of an adhesive was added. Obtained. The following photopolymerization initiator and isocyanate curing agent were used.
Photopolymerization initiator: manufactured by Nippon Siber Hegner, Esacure One Isocyanate Curing agent: manufactured by Tosoh, Coronate L

(Production of base material)
An anchor agent was prepared by mixing 20 parts by weight of Rheorosil MT10 manufactured by Tokuyama Corporation as an inorganic filler with 100 parts by weight of a mixture of AP2503D2 manufactured by Arakawa Chemical Industries, Ltd., CL2503, and RA-1000.
The obtained anchor agent is applied on a release-treated surface of a polyethylene terephthalate film (temporary protective film, width 550 mm) having a thickness of 50 μm and subjected to one-side release treatment with a comma coater so that the thickness of the dry film is 5 μm. And dried at 110° C. for 5 minutes. After that, a transparent polyethylene terephthalate film having a thickness of 125 μm (base material, width of 550 mm) was attached on one surface to form a three-layer sheet of base material/anchor layer/temporary protective film.

(Manufacture of adhesive tape)
On the pre-release treated surface of the release film (width: 550 mm) obtained in the production of the release film, the ethyl acetate solution of the obtained pressure-sensitive adhesive was put into a comma so that the width was 530 mm and the thickness of the dry film was 200 μm. It was applied with a coater and dried at 110° C. for 5 minutes to form an adhesive layer. After that, the temporary protective film of the three-layer sheet of the base material/anchor layer/temporary protective film produced above is peeled off, the anchor agent layer and the pressure-sensitive adhesive layer are stuck together, and static curing is carried out at 40° C. for 3 days. Thus, an adhesive tape comprising a substrate/anchor layer/adhesive layer/release film was obtained.

(Production of rolls)
The obtained adhesive tape was wound around a 6-inch ABS resin core to obtain a roll-shaped body having a width of 550 mm and a winding length of 30 m (winding tension: 80 N/m).

(Slit processing of rolls)
The roll-shaped body was slitted using a shear blade type slitter to obtain a small winding roll having a width of 100 mm and a winding length of 30 m.

(Manufacture of adhesive tape rolls)
An adhesive tape was pulled out from the obtained small roll, the release film was replaced with the release film obtained in the production of the release film having a width of 101 mm, and the roll was rewound to obtain an adhesive tape roll. The release film having a width of 101 mm was re-attached so that the front release-treated surface was the surface on the pressure-sensitive adhesive layer side.

(Measurement of protrusion width of release film to substrate)
The periphery of the end in the width direction of the adhesive tape was enlarged with a microscope, and the width of the release film protruding from the substrate was measured using the attached image processing software. Specifically, a long adhesive tape is cut to a length of 100 cm, the length of the release film protruding from the base material is measured at the widthwise end of the base material, and the measured values are averaged. did. The measurement was made at points (at intervals of 0.2 m) that divide the long adhesive tape into five equal parts in the length direction, and the measurement was carried out at a total of 6 points, the start point and the end point of each section.

(Measurement of release force of release film)
The adhesive tape was cut into a size of width 25 mm×length 100 mm to obtain a strip-shaped test piece. The obtained test piece was subjected to a tensile test in the direction of 180° at a peeling rate of 300 mm/min according to JIS Z0237 to measure the peeling force of the release film.

(Measurement of water contact angle of release film)
The release film was peeled from the adhesive tape, and the release film was cut into a width of 25 mm to obtain a test piece. The surface of the obtained test piece which was not in contact with the pressure-sensitive adhesive layer was placed horizontally as an upper surface, and 2 μL of water droplets (at a temperature of 25° C. and a humidity of 40% on the surface of the release film in accordance with JIS R 3257:1999) Pure water) was added dropwise. The angle formed by the pure water and the surface of the release film 5 seconds after the dropping was measured using a contact angle measuring device (CAM 200, manufactured by KSV), and the surface opposite to the surface of the release film in contact with the adhesive layer was measured. The contact angle of water on the side surface (water contact angle) was measured.

(Measurement of bending resistance of release film)
The release film was cut into a strip having a width of 20 mm and a length of 200 mm to obtain a sample piece. The bending resistance was measured using the bending resistance A method (45° cantilever method) described in JIS L1084. In addition, the measurement limit of the device is 150 mm, and those exceeding this limit are set to "150<".

(Measurement of the width of the adhesive layer protruding from the substrate)
The periphery of the end portion in the width direction of the adhesive tape was enlarged with a microscope (digital microscope VHX-6000, manufactured by Keyence Corporation), and the width of the adhesive layer protruding from the substrate was measured using the attached image processing software. Specifically, a long adhesive tape is cut into a length of 100 cm, the length of the adhesive layer protruding from the base material is measured at the widthwise end of the base material, and the measured values are averaged. did. The measurement was made at points (at intervals of 0.2 m) that divide the long adhesive tape into five equal parts in the length direction, and the measurement was carried out at a total of 6 points, the start point and the end point of each section.

(Measurement of width of protrusion of release film from adhesive layer)
The periphery of the end in the width direction of the adhesive tape was enlarged with a microscope, and the width of the adhesive layer protruding from the substrate was measured using the attached image processing software. Specifically, a long adhesive tape was cut into a length of 100 cm, the length of the release film protruding from the adhesive layer was measured at the end in the width direction, and the measured values were averaged. The measurement was made at points (at intervals of 0.2 m) that divide the long adhesive tape into five equal parts in the length direction, and the measurement was carried out at a total of 6 points, the start point and the end point of each section. When the adhesive layer was longer, the difference was measured as a negative value.

(Measurement of gel fraction)
Only 0.1 g of the adhesive layer of the adhesive tape was scraped off, immersed in 50 ml of ethyl acetate, and shaken with a shaker at a temperature of 23° C. and 200 rpm for 24 hours (hereinafter, the scraped off adhesive layer That is referred to as the adhesive composition). After the shaking, a metal mesh (opening #200 mesh) was used to separate the ethyl acetate-soluble component and the pressure-sensitive adhesive composition that absorbed the ethyl acetate and swollen. The pressure-sensitive adhesive composition after separation was dried for 1 hour at 110°C. The weight of the pressure-sensitive adhesive composition containing the dried metal mesh was measured, and the gel fraction of the pressure-sensitive adhesive layer was calculated using the following formula. The results are shown in Table 1.
Gel fraction (% by weight)=100×(W ₁ −W ₂ )/W ₀
(W ₀ : weight of initial pressure-sensitive adhesive composition, W ₁ : weight of pressure-sensitive adhesive composition containing dried metal mesh, W ₂ : initial weight of metal mesh)

(Measurement of storage elastic modulus of adhesive layer)
When manufacturing an adhesive tape, instead of sticking the pressure-sensitive adhesive layer to the anchor agent layer, the pressure-sensitive adhesive layer is bonded to the front release treated surface of the release film to form a release film/adhesive layer/release film. A measurement sample was prepared. After removing the release films on both sides of the obtained measurement sample, measurement is performed using a dynamic viscoelasticity measuring device (DVA-200, manufactured by IT Measurement and Control Co., Ltd.) under conditions of shear mode and angular frequency of 1 Hz. The storage elastic modulus at 25° C. of the adhesive layer was measured.

(Examples 2 to 4, Comparative Examples 8 and 9)
An adhesive tape was produced in the same manner as in Example 1 except that the thickness of the PET film used for producing the release film was changed as shown in Tables 1 and 3, and the above-mentioned measurement was performed after forming an adhesive tape roll.

(Examples 5 to 8)
An adhesive tape was produced in the same manner as in Example 1 except that the compounding amount of the isocyanate curing agent was changed as shown in Table 1 in the production of the adhesive, and the adhesive tape roll was subjected to the above measurement.

(Examples 9 and 11)
In the production of a release film, an adhesive tape was produced in the same manner as in Example 1 except that the silicone release agent applied to the surface not subjected to the release treatment was as shown in Tables 1 and 2, and an adhesive tape roll was produced. Then, the above measurement was performed. The details of the silicone release agent are as follows.
Silicone release agent B: KS-774, manufactured by Shin-Etsu Silicone Co., Ltd.
Silicone release agent C: KS-847 manufactured by Shin-Etsu Silicone Co., Ltd.

(Example 10)
In the production of the release film, the following PET film was used, and the release agent A diluted with toluene was applied to the corona-treated surface so that the contact angle of water on the application surface was 89°. An adhesive tape was produced in the same manner as in Example 1 except that it was adjusted, and the adhesive tape roll was subjected to the above measurement.
PET film B: manufactured by Toyo Cross Co., Ltd., non-silicone PET release film (thickness 50 μm), Tokuro release film SP4107

(Examples 12 to 13, Comparative Examples 3 to 4)
In the production of the release film, an adhesive tape was produced in the same manner as in Example 1 except that the PET film was changed to the following, and the adhesive tape roll was used for the above measurement.
PET film C: manufactured by Toyo Cross Co., Ltd., non-silicone PET release film (thickness 50 μm), Tokuro release film SP2005-50
PET film D: manufactured by Lintec, non-silicone PET release film (thickness 50 μm), release film PET T314
PET film E: manufactured by Nakamoto Pax, silicone-based PET release film (thickness 50 μm), NS separator MXA
PET film F: Lintec, non-silicone PET release film (thickness 50 μm), release film PET50X

(Examples 14 to 16 and Comparative Examples 1 and 2)
An adhesive tape was produced in the same manner as in Example 1 except that the protrusion width of the release film was changed to that shown in Tables 2 and 3 by adjusting the width of the release film when replacing the release film of the small roll. The above measurement was carried out on an adhesive tape roll. In addition, in the table, when the protrusion width of the release film with respect to the pressure-sensitive adhesive layer is a negative value, it means that the width of the pressure-sensitive adhesive layer is longer than that of the release film.

(Example 17, Comparative Example 7)
In the production of the pressure-sensitive adhesive, the pressure-sensitive adhesive tape was produced in the same manner as in Example 1 except that the compounding amount of the isocyanate curing agent and the thickness of the pressure-sensitive adhesive layer were changed as shown in Tables 2 and 3, and the above-mentioned measurement was performed. I went.

(Comparative example 5)
In the production of the release film, the following PET film was used, the corona treatment and the application of the silicone release agent were not performed, and the surface of the release film subjected to the release treatment was the adhesive layer. An adhesive tape was produced in the same manner as in Example 1 except that the surface was in contact with the adhesive tape roll, and the above measurement was performed.
PET film G: Toray, PET film (thickness 50 μm), S-10

(Comparative example 6)
In the production of the release film, the following PET film was used, the corona treatment and the application of the silicone release agent were not performed, and the surface of the release film which was not subjected to the release treatment was the adhesive layer. An adhesive tape was produced in the same manner as in Example 1 except that the surface was in contact with the adhesive tape roll, and the above measurement was performed.
PET film H: Unitika Fluorine-based PET release film (thickness 50 μm), Unipeal FCT

<Evaluation>
The adhesive tape rolls obtained in Examples and Comparative Examples were evaluated by the following methods. The results are shown in Tables 1 to 3.

(Evaluation of rewindability)
The obtained pressure-sensitive adhesive tape roll was allowed to stand for 1 month under the condition of 40°C. The roll-shaped body after standing was unwound and the unwinding property was evaluated according to the following criteria.
◎: All can be smoothly rewound without adhesion on the side surface of the roll ○: There is partial adhesion on the core side of the side surface of the roll, but it can be rewound by applying light force ×: Side surface of the roll Glued and all unwinding impossible

(Evaluation of peeling and floating of release film)
The interface between the release film and the pressure-sensitive adhesive layer of the pressure-sensitive adhesive tape rewound from the pressure-sensitive adhesive tape roll was observed with an optical microscope, and peeling and floating of the release film were evaluated according to the following criteria.
◎: No peeling ○: There was peeling less than 1 mm in length from the widthwise end of the adhesive layer, and there were 3 or less places ×: Peeling less than 1 mm in length from the widthwise end of the adhesive layer. There are 4 or more points, or there is peeling of 1 mm or more in length from the end of the adhesive layer in the width direction.

(Evaluation of conformability to unevenness)
The release film was peeled off from the pressure-sensitive adhesive tape, and the surface on the pressure-sensitive adhesive layer side was attached to a bumped TEG (Test Element Group, WLP TEG (0.3 mm pitch BGA, manufactured by Waltz)). The end area (50 mm×50 mm) of the bumped TEG after sticking the adhesive tape was observed with an optical microscope (×100 times), and the conformability to the unevenness of the adhesive tape was evaluated according to the following criteria.
⊚: The bumps are completely filled ◯: Less than 5 voids are observed around the bumps Δ: 5 or more voids are observed around the bumps

(Evaluation of winding deviation)
The adhesive tape roll was placed under the condition of 23° C. for 7 days so that one side of the adhesive tape roll faced down, and then a ruler was placed along the tape surface of the adhesive tape roll, and the winding deviation of the side surface was read. The winding deviation was evaluated according to the following criteria.
◎: Winding deviation is less than 1.5 mm ◯: Winding deviation is 1.5 mm or more and less than 2.0 mm ×: Winding deviation is 2.0 mm or more

(Evaluation of surface roughness after peeling the release film)
The release film was peeled off from the pressure-sensitive adhesive tape, and the surface of the pressure-sensitive adhesive layer after peeling, the interface between the substrate/anchor agent layer and the interface between the anchor agent layer/pressure-sensitive adhesive layer were visually observed. The surface roughness after peeling the release film was evaluated according to the following criteria.
⊚: No surface roughness is observed on the surface of the pressure-sensitive adhesive layer, and voids due to peeling are not observed at the interface of the substrate/anchor agent layer and the interface of the anchor agent layer/pressure-sensitive adhesive layer. ◯: The surface of the pressure-sensitive adhesive layer is rough. However, voids due to peeling are not observed at the interface of the base material/anchor layer and the interface of the anchor agent layer/adhesive layer x: The surface of the adhesive layer is rough, and the interface between the base material/anchor layer or the anchor agent Voids due to peeling are observed at the layer/adhesive layer interface

According to the present invention, it is possible to suppress the rewinding failure from the roll when stored for a long time, the peeling performance of the release film is high while suppressing the peeling and the tunneling of the release film, and the sticking which is less likely to cause winding deviation A tape and an adhesive tape roll made of the adhesive tape can be provided.

1 Conventional Adhesive Tape 2 Adhesive 3, 3', 3" Adhesive Tape 4, 4', 4" Substrate 5, 5', 5" Adhesive Layer 6, 6', 6" Release Film

Claims (5)

A long adhesive tape having a substrate, an adhesive layer and a release film,
At the end of the pressure-sensitive adhesive tape, the length in the width direction of the release film is 0.1 mm or more and 50 mm or less longer than the length in the width direction of the base material, and the length in the width direction of the pressure-sensitive adhesive layer is the base. 0.7 mm or more longer than the length of the material in the width direction,
The release force of the surface of the release film on the side in contact with the pressure-sensitive adhesive layer is 0.03 to 10 N/25 mm,
The contact angle of water on the surface of the release film opposite to the surface in contact with the pressure-sensitive adhesive layer is 85 to 113°,
An adhesive tape in which the release film has a bending resistance of 30 mm or more and 150 mm or less. The adhesive tape according to claim 1, wherein the gel fraction of the adhesive layer is 1% or more and 65% or less. The pressure-sensitive adhesive tape according to claim 1, wherein the pressure-sensitive adhesive layer has a storage elastic modulus G′ at 23° C. of 5.0×10 ³ Pa or more and 2.0×10 ⁸ Pa or less. The pressure-sensitive adhesive tape according to claim 1, 2 or 3, wherein the pressure-sensitive adhesive layer has a thickness of 100 to 500 µm. An adhesive tape roll comprising the adhesive tape according to claim 1, 2, 3, or 4.

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