Adhesive tape

Abstract

To provide an adhesive tape that has both of excellent impact resistance and excellent cuttability.SOLUTION: An adhesive tape includes an adhesive layer. The adhesive layer contains silicone composite fillers with a number average primary particle size of 3-45 μm, micro balloons with a number average primary particle size of 5-45 μm, and an adhesive resin. Relative to 100 pts.mass of the adhesive resin, the content of the silicone composite fillers is 10-50 pts.mass. The content of the micro balloons is 1-25 pts.mass.SELECTED DRAWING: None

Description

[Technical field]

[0001] The present invention relates to an adhesive tape. [Background technology]

[0002] Adhesive tapes are highly convenient due to their excellent workability and instantaneous adhesion properties, and are widely used as a joining means in various industrial fields such as electronic devices including information devices, IT and home appliances, and automobiles for purposes such as fixing parts, temporarily fixing parts, and labeling to display product information. In particular, adhesive tapes used as joining means for components of electronic devices such as terminal devices are required to have not only adhesive strength but also holding power to prevent peeling or slippage, and at the same time, ease of peeling or removal without damaging the adherend when replacing the components or dismantling the terminal devices for recycling is also required.

[0003] An example of technology relating to an adhesive tape that has both adhesive strength and ease of peeling or removal is Patent Document 1. The technology in Patent Document 1 examines the shear adhesive strength, breaking strength, elongation at break, and tension after removal is interrupted, and describes that the adhesive sheet in Patent Document 1 has a specified shear adhesive strength, breaking strength, and elongation at break, and therefore adheres well to the adherend and can be removed without damaging it. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] JP 2016-29155 A Summary of the Invention [Problem to be solved by the invention]

[0005] However, Patent Document 1 does not consider the holding power, which indicates the durability of the viscoelastic body, and therefore there is a risk that the adhesive tape may peel off or shift while the electronic device is in use. Furthermore, since electronic devices, particularly terminal devices for portable use, are likely to be accidentally dropped when being carried or used, there is a demand for adhesive tapes for fixing with improved impact resistance so that the terminal devices do not come apart due to the impact of being dropped. Therefore, in order to ensure the required impact resistance, it is necessary to make the adhesive layer extremely flexible (reducing the elastic modulus.) However, when the adhesive layer becomes flexible, a new problem occurs in that cutting processability becomes poor in punching or slitting.

[0006] Therefore, the present invention has been made in consideration of the above problems, and an object of the present invention is to provide an adhesive tape that combines excellent impact resistance and good cuttability. [Means for solving the problem]

[0007] In view of the above problems, the present inventors have conducted intensive research and repeated experiments, and as a result have found that the above problems can be solved by using an adhesive tape having an adhesive resin layer in which a specific silicone composite filler, specific microballoons, and an adhesive resin are mixed in a specific ratio, thereby completing the present invention.

[0008] [1] This embodiment is an adhesive tape having an adhesive layer, the adhesive layer containing a silicone composite filler having a number average primary particle diameter of 3 to 45 μm, microballoons having a number average primary particle diameter of 5 to 50 μm, and an adhesive resin; The adhesive tape is characterized in that the content of the silicone composite filler is 10 to 50 parts by mass and the content of the microballoons is 1 to 25 parts by mass relative to 100 parts by mass of the adhesive resin. [2] This embodiment is an adhesive tape having an adhesive layer, the adhesive layer being formed from a composition for adhesive layer containing a silicone composite filler having an average particle size of 10 to 40 μm, microballoons having an average particle size of 10 to 50 μm, and an adhesive resin; The adhesive tape is characterized in that the content of the silicone composite filler is 10 to 50 parts by mass and the content of the microballoons is 1 to 25 parts by mass relative to 100 parts by mass of the adhesive resin. [3] In the present embodiment, the volume ratio of the microballoons to the total volume of the adhesive layer is preferably 5 to 30 volume %. [4] In this embodiment, the microballoons are hollow particles having a surface layer containing a first resin, and an inorganic material is attached to the surface of the surface layer. [5] In the present embodiment, when the average thickness of the adhesive layer is taken as 1, the ratio of the number average primary particle size of the silicone composite filler to the thickness of the adhesive layer is preferably within a range of 0.1 to 0.7. [6] In this embodiment, when the average thickness of the adhesive layer is taken as 1, the ratio of the number average primary particle size of the microballoons to the thickness of the adhesive layer is preferably within a range of 0.1 to 0.5. [7] In the present embodiment, the adhesive layer further contains an acrylic-modified silicone, and the content of the acrylic-modified silicone is preferably 0.1 to 30 parts by mass relative to 100 parts by mass of the adhesive resin. [9] In the present embodiment, it is preferable that a substrate is further provided, and the adhesive layer is provided on one or both sides of the substrate.

[10] In the present disclosure, the base material preferably has a breaking elongation of 400 to 1500%. Effect of the Invention

[0009] According to the present invention, there is provided an adhesive tape which combines excellent impact resistance with good cuttability. [Brief description of the drawings]

[0010] [Figure 1] FIG. 1 is a schematic plan view of a test piece 10 used in the evaluation method for impact resistance in the examples. [Diagram 2]FIG. 2 is a schematic diagram illustrating a method for evaluating impact resistance in the examples. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0011] The following describes in detail an embodiment of the present invention (hereinafter referred to as the "present embodiment"); however, the present invention is not limited to the following description and can be implemented in various modified forms within the scope of the gist thereof.

[0012] (adhesive tape) The adhesive tape of this embodiment includes an adhesive layer, and the adhesive layer includes a silicone composite filler having a number average primary particle diameter of 3 to 45 μm, microballoons having a number average primary particle diameter of 5 to 50 μm, and an adhesive resin. In other words, the adhesive layer is formed from a composition for an adhesive layer, which contains a silicone composite filler having an average particle diameter of 10 to 40 μm, microballoons having an average particle diameter of 10 to 50 μm, and an adhesive resin. The content of the silicone composite filler in the adhesive layer is 10 to 50 parts by mass relative to 100 parts by mass of the adhesive resin. The content of the microballoons in the adhesive layer is 1 to 25 parts by mass relative to 100 parts by mass of the adhesive resin. The adhesive tape of the present embodiment has an adhesive layer in which silicone composite filler and microballoons having a predetermined number average primary particle size are dispersed in a matrix containing an adhesive resin, and therefore can ensure excellent impact resistance and good cutting processability. In addition, the adhesive tape of the present embodiment has an adhesive layer formed from a composition for an adhesive layer that contains an adhesive resin, and silicone composite filler and microballoons having a predetermined average particle size, so that the silicone composite filler and microballoons are easily dispersed in a matrix containing an adhesive resin. In this specification, the "average particle size" and the "number average primary particle size" are distinguished from each other because the measurement methods for the two are different. In this specification, the "average particle size" refers to the volume average particle size measured by a laser diffraction scattering method for a single particle (for example, either a silicone composite filler or a microballoon). On the other hand, in this specification, the "number average primary particle size" refers to the number average of the primary particle size calculated from an electron microscope image in a system in which the silicone composite filler and the microballoons are mixed. The details of the measurement method for the "average particle size" and "number average primary particle size" of the silicone composite filler or the microballoons in the present invention will be described later. The reason for specifying different "particle sizes" for the same particle is that in a mixed system containing two or more types of particles, it may be difficult to identify the size of each particle even using current analytical equipment, so both the "average particle size", which indicates the size of each particle in the raw material before the adhesive layer is formed, and the "number average primary particle size", which indicates the size of each particle in the formed adhesive layer, are listed.

[0013] The adhesive tape of this embodiment only needs to have an adhesive layer, and may further have a base layer if necessary. That is, the adhesive tape of this embodiment preferably has a base layer and an adhesive layer on one or both sides of the base layer. The adhesive layer, which is a component of the adhesive tape, and the base layer, which is an optional element, are described below.

[0014] [Adhesive layer] In this embodiment, the adhesive tape has an adhesive layer for exerting adhesive strength. The adhesive layer contains a silicone composite filler having a number average primary particle diameter of 3 to 45 μm, microballoons having a number average primary particle diameter of 5 to 50 μm, and an adhesive resin. In other words, the adhesive layer is formed from a composition for adhesive layer containing a silicone composite filler having an average particle diameter of 10 to 40 μm, microballoons having an average particle diameter of 10 to 50 μm, and an adhesive resin. The adhesive layer of this embodiment contains 10 to 50 parts by mass of the silicone composite filler and 1 to 25 parts by mass of the microballoons relative to 100 parts by mass of the adhesive resin.

[0015] In addition, in this embodiment, the adhesive layer or the composition for the adhesive layer may contain, in addition to the essential components of the silicone composite filler, microballoons and adhesive resin, an acrylic-modified silicone, an optional component of the adhesive layer, a solvent (e.g., a known organic solvent) or other adhesive resins, as necessary. Furthermore, the frictional force of the outer surface of the adhesive layer in this embodiment is preferably 0.1 to 5.0N, more preferably 0.12 to 4.8N, even more preferably 0.3 to 4.0N, and particularly preferably 0.5 to 3.0N. In the adhesive tape of this embodiment, when the friction force of the outer surface of the adhesive layer is within the above range, the adhesive tape can be peeled off more easily and quickly even when the stretching direction of the adhesive tape is at a relatively large angle, for example a vertical direction, relative to the application surface of the adherend, and even when the adhesive tape is stretched at a high speed. In the present embodiment, a specific means for achieving the above range of friction force of the outer surface of the adhesive layer is a form in which the adhesive layer contains a silicone composite filler having a number average primary particle diameter of 3 to 45 μm, microballoons having a number average primary particle diameter of 5 to 50 μm, an adhesive resin, and an acrylic modified silicone. Therefore, the adhesive layer composition forming the adhesive layer of the present embodiment preferably contains a silicone composite filler, microballoons, an adhesive resin, and an acrylic modified silicone, the silicone composite filler using particles having an average particle diameter of 10 to 40 μm, and the microballoons using particles having an average particle diameter of 10 to 50 μm.

[0016] <Silicone composite filler> The adhesive layer of the present embodiment contains a silicone composite filler. The silicone composite filler in the adhesive layer has a number average primary particle size of 3 to 45 μm. Meanwhile, the silicone composite filler used as a raw material for preparing the adhesive layer composition has an average particle size of 10 to 40 μm. In the silicone composite filler of the present embodiment, the surfaces of the rubber particles are preferably coated with a silicone resin. When a silicone composite filler having a predetermined number average primary particle size is present in the adhesive layer, a large number of cavities or shear yields are generated near the filler dispersed in the matrix, absorbing energy at the time of impact, which is believed to improve impact resistance. In particular, when a core-shell type silicone composite filler having rubber particles as a core and silicone resin as a shell is used, the aggregation of the fillers can be suppressed due to the effect of the silicone resin coating on the surface. This improves the dispersibility of the silicone composite filler in the adhesive layer, so that when impact occurs, very small cavities are generated on the surface of the silicone composite filler and the adhesive layer composition, which efficiently absorbs energy at the time of impact, and is believed to further improve impact resistance. However, if the filling rate of the filler in the adhesive layer is increased with emphasis on the required impact resistance, the relative amount of the adhesive resin decreases, and the adhesive performance decreases. The trade-off relationship between impact resistance and adhesive performance also shows a similar tendency when microballoons are blended, which will be described later. However, it has been confirmed that when a certain silicone composite filler and microballoons, which will be described later, coexist in the adhesive layer, high adhesive strength is maintained while improving impact resistance. Although the reason is unclear, it is considered that when fillers and microballoons of different particle sizes and materials are mixed, the aggregation of the fillers or the balloons is suppressed, and the dispersion state of the adhesive layer is improved. In addition, it is presumed that, rather than the possibility of crazes occurring due to impact force between the adhesive layer composition and the silicone composite filler, countless bubbles (cavities) are generated due to minute peeling from the interface of the silicone composite filler, absorbing the energy of the impact.

[0017] In addition, since the adhesive layer contains a silicone composite filler, the filler is exposed from the adhesive layer when the adhesive tape is stretched, the adhesive area between the adhesive layer and the adherend is reduced, and the filler present on the adhesive surface reduces frictional resistance, so that the adhesive strength can be effectively reduced. Therefore, even if the stretching direction of the adhesive tape is at a relatively large angle to the application surface of the adherend, for example, a vertical direction (sometimes called a "90° direction"), or even if the adhesive tape is stretched at a high speed, the adhesive tape is easily and quickly peeled off, making it easy to remove.

[0018] In addition, when a silicone composite filler or the like is contained in the adhesive layer or the composition for the adhesive layer, the addition of the filler may cause a decrease in adhesive performance. However, since the silicone composite filler has good dispersibility in the composition for the adhesive layer or the adhesive layer, the decrease in adhesive performance caused by the addition of the filler is suppressed, and the adhesive strength of the adhesive tape can be ensured. Although the reason for the good dispersibility is not clear, it is presumed that the silicone composite filler has low surface energy due to the effect of the silicone resin on the surface, making it difficult for adhesion between particles to occur, and therefore does not cause or is difficult for aggregation of secondary particles to occur.

[0019] The silicone composite filler in this embodiment is preferably a particle having a silicone resin on a part or the whole of the surface. The silicone composite filler can have an internal material other than a silicone resin (in other words, for example, a particle other than a silicone resin, the surface of which is coated with a silicone resin). Preferably, the internal material is a rubber particle having rubber elasticity such as silicone rubber. If the internal material of the filler is an elastic material having elasticity, the adhesive performance of the adhesive layer can be more effectively ensured. The reason for this is unclear, but it is presumed that when the filler is mixed with a solvent or the like when forming an adhesive layer or a composition for an adhesive layer, the silicone composite filler absorbs the solvent that has permeated the silicone resin surface, and exhibits compatibility with the adhesive resin or can suppress aggregation, compared to a filler that is entirely made of silicone resin. Then, by improving the compatibility, the decrease in the adhesive performance of the adhesive layer is further suppressed. The silicone composite filler may be used alone or two or more types may be mixed and used in combination.

[0020] A preferred silicone composite filler of this embodiment is a composite particle having a rubber particle as a core and a silicone resin as a shell that covers part or all of the core. Examples of the rubber particles include acrylic rubber particles, NBR rubber particles, and silicone rubber particles, and silicone rubber particles are preferred. The silicone rubber particles are preferably those having a structure in which dimethylpolysiloxane, organopolysiloxane, or polyorganosilsesquioxane is crosslinked, and are preferably prepared from organopolysiloxane or organopolysilsesquioxane having a group selected from monovalent organic groups having 1 to 20 carbon atoms. The monovalent organic groups include one or more groups selected from the group consisting of alkyl groups such as methyl groups, ethyl groups, propyl groups, and butyl groups; aryl groups such as phenyl groups and tolyl groups; alkenyl groups such as vinyl groups and allyl groups; aralkyl groups such as β-phenylethyl groups and β-phenylpropyl groups; monovalent halogenated hydrocarbon groups such as chloromethyl groups and 3,3,3-trifluoropropyl groups; epoxy groups, amino groups, mercapto groups, acryloxy groups, and methacryloxy groups. Examples of the silicone resin include silicone resin powders which are fine powders of polyorganosilsesquioxane, such as the silicone resins described in JP-B-40-16917, JP-A-54-72300, JP-A-60-13813, JP-A-3-244636, and JP-A-4-88023.

[0021] Specific examples of silicone composite fillers having a silicone rubber core and a silicone resin shell include silicone rubber particles obtained by three-dimensionally crosslinking linear organopolysiloxane (see JP-A-63-77942, JP-A-3-93834, and JP-A-4-198324), and particles of powdered silicone rubber (see U.S. Pat. No. 3,843,601, JP-A-62-270660, and JP-A-59-96,122), the surface of which is treated with (R'SiO 3 / 2)n (R' represents a substituted or unsubstituted monovalent hydrocarbon group) and having a three-dimensional network-like crosslinked structure, the silicone resin-coated particles are polyorganosilsesquioxane cured products (see JP-A-7-196815). As particles in which the silicone composite filler itself is formed of silicone resin, polyorganosilsesquioxane fine powder can be used. The fillers may be used alone or in combination of two or more kinds.

[0022] As the silicone composite filler, there can be used products commercially available under the above trade names, such as Torayfil E-500, Torayfil E-600, Torayfil E-601, and Torayfil E-850, from Dow Corning Toray Silicone Co., Ltd., and KMP-600, KMP-601, KMP-602, KMP-605, and X-52-7030, from Shin-Etsu Chemical Co., Ltd. A mixture of two or more of these can also be used.

[0023] In this embodiment, the shape of the silicone composite filler is not particularly limited and can be appropriately selected according to the purpose, and may be a regular shape or an irregular shape. Specific examples of the shape of the filler include polygonal, cubic, elliptical, spherical, rod-like, needle-like, flat, and scaly shapes. Among these, the shape of the filler is preferably an elliptical, spherical, or polygonal shape, and more preferably a spherical shape. When the filler is elliptical, spherical, rod-like, or polygonal shape, the adhesive layer can slide well against the adherend when the adhesive tape is stretched, and the adhesive tape can be peeled off more easily and quickly. The silicone composite fillers having these shapes may be used alone or in combination of two or more types.

[0024] In this embodiment, the particle size distribution (D90 / D10) of the silicone composite filler used in the adhesive layer composition is not particularly limited and can be appropriately selected depending on the purpose, but is preferably 2.5 to 20, and from the viewpoint of impact resistance, is more preferably 2.5 to 15, and is even more preferably 2.5 to 5. When the particle size distribution (D90 / D10) of the silicone composite filler used in the adhesive layer composition is within a preferred range, the adhesive tape can be peeled off more easily and quickly, and even if the thickness of the adhesive tape base material is thin, it is difficult to tear, and has excellent impact resistance, shear adhesive strength, and cleavage adhesive strength. On the other hand, when the particle size distribution (D90 / D10) of the silicone composite filler used in the adhesive layer composition is less than 2.5, the stretch peelability may be impaired, and when it exceeds 20, the adhesive performance such as impact resistance, shear adhesive strength, and cleavage adhesive strength may be impaired. The particle size distribution (D90 / D10) of the silicone composite filler used in the adhesive layer composition in this embodiment can be obtained by measuring the average particle size of the particles using a measuring device (Microtrack) that uses a laser diffraction scattering method and converting it into a particle size distribution.

[0025] In this embodiment, the number average primary particle diameter of the silicone composite filler present in the adhesive layer is 3 to 45 μm, preferably 5 to 40 μm, more preferably 10 to 35 μm, even more preferably 10 to 33 μm, and most preferably 10 to 32 μm. On the other hand, the average particle size of the silicone composite filler used in the adhesive layer composition is 5 to 50 μm, preferably 8 to 48 μm, more preferably 12 to 45 μm, even more preferably 13 to 43 μm, and most preferably 14 to 40 μm. When a drop impact force is applied to the adhesive tape of this embodiment, a cavity formed at the interface between the adhesive layer composition or adhesive resin and the silicone composite filler makes it easier to obtain suitable drop impact resistance. In addition, when the adhesive tape is stretched to peel it off, the adhesive tape can be peeled off more easily and quickly. For example, when the adhesive tape has a base layer, even if the base thickness of the adhesive tape is thin, it is less likely to tear, and has excellent effects in impact resistance, shear adhesive strength, and split adhesive strength. If the number average primary particle diameter of the silicone composite filler is less than 3 μm, the cavity formed at the interface between the adhesive resin and the silicone composite filler when a drop impact force is applied may be too small, making it difficult to exhibit suitable drop impact resistance. On the other hand, if the number average primary particle diameter of the silicone composite filler particles exceeds 45 μm, coarse particles are likely to exist, so there is a concern that coarse particles larger than the thickness of the adhesive layer may be mixed in, making it difficult to obtain suitable adhesive strength. In addition, adhesive performance such as drop impact resistance, impact resistance, shear adhesive strength, and split adhesive strength may be impaired. For the same reason, if the average particle diameter of the silicone composite filler is 10 μm or more, the formed adhesive layer may be more likely to exhibit suitable drop impact resistance. And, if the average particle diameter of the silicone composite filler is 40 μm or less, suitable adhesive strength is more likely to be exhibited. In this specification, the "average particle size of the silicone composite filler" refers to the particle size of the silicone composite filler alone before it is added to the adhesive layer composition, and refers to the volume average particle size measured by a measuring device (Microtrack) using a laser diffraction scattering method. The average particle size of the silicone composite filler is measured under the measurement conditions described in the Examples section below.

[0026] In this specification, the "number average primary average particle size of the silicone composite filler" refers to the size of the particles of the silicone composite filler present in the adhesive layer, and the number average primary average particle size of the silicone composite filler present in the adhesive layer is measured using the following method. First, the adhesive tape cooled under liquid nitrogen was cut at three random locations using a microtome, and the three pieces were used as samples. Then, a photograph was taken of each sample at a magnification of 400 times using a scanning electron microscope, and from the three photographs taken, the hollow particles were selected as microballoons, and the solid particles were selected as silicone composite filler. Then, the cross-sectional areas of the hollow bodies and solid bodies calculated by binarization processing (for example, Otsu's binarization processing) using image analysis software were regarded as the area of ​​a circle, and the circle equivalent diameters of each of the hollow bodies and solid bodies were measured. Then, the total number of hollow bodies and solid bodies in the three photographs and the corresponding circle equivalent diameters were calculated, and the number average primary average particle size of the silicone composite filler was calculated from the following formula (A).

number

[0027] In this embodiment, the ratio of the number average primary particle diameter of the silicone composite filler to the average thickness of the adhesive layer is not particularly limited and can be appropriately selected depending on the purpose. The ratio of the number average primary particle diameter of the silicone composite filler to the thickness of the adhesive layer, represented by [number average primary particle diameter of the silicone composite filler / average thickness of the adhesive layer], is preferably 5 / 100 or more, more preferably 5 / 100 to 95 / 100, even more preferably 10 / 100 to 75 / 100, and particularly preferably 20 / 100 to 60 / 100. When the ratio is 5 / 100 or more, cavities are easily formed at the interface between the adhesive layer composition or adhesive resin and the silicone composite filler when a drop impact force is applied to the adhesive tape of this embodiment, and coarse particles are unlikely to exist, so that drop impact resistance is good. In addition, in the operation of stretching and peeling the adhesive tape, the adhesive tape can be peeled off more easily and quickly. Therefore, for example, when an adhesive tape has a base layer, it is difficult to tear even if the base layer of the adhesive tape is thin. Also, if the ratio is 95 / 100 or less, it is advantageous in that the adhesive performance such as drop impact resistance, impact resistance, shear adhesive strength, and split adhesive strength is also more excellent.

[0028] The content of the silicone composite filler in the adhesive layer is 3 to 50 parts by mass, preferably 5 to 45 parts by mass, and more preferably 7.5 to 40 parts by mass, relative to 100 parts by mass of the adhesive resin. By having the content of the silicone composite filler be 10 parts by mass or more relative to 100 parts by mass of the adhesive resin, it is possible to ensure both impact resistance and cuttability, or to ensure ease of peeling. In addition, by having the content of the silicone composite filler be 50 parts by mass or less relative to 100 parts by mass of the adhesive resin, it is possible to prevent the adhesive layer from remaining on the adherend, the impact resistance from decreasing, and the shear adhesive strength or the split adhesive strength from decreasing. The content of the filler in the adhesive layer can be appropriately adjusted when preparing the composition for the adhesive layer.

[0029] In this embodiment, the volume ratio of the silicone composite filler to the entire volume of the adhesive layer is preferably 5 to 50%, more preferably 10 to 50%, even more preferably 15 to 50%, and most preferably 20 to 50%. When the volume ratio of the filler is 5% or more, the adhesive tape can be peeled off more easily and quickly. Furthermore, when the volume ratio of the silicone composite filler is 50% or less, it is possible to prevent the adhesive layer from remaining on the adherend, the impact resistance from decreasing, and the shear adhesive strength or split adhesive strength from decreasing.

[0030] In this specification, the volume ratio (volume %) of the silicone composite filler to the adhesive layer can be calculated from the following formulas (1) to (3). Adhesive Resin *1 Mass A (g) / Adhesive resin *1 Density A (g / cm 3 ) = Adhesive resin *1 Volume A (cm 3 )...Equation (1) Silicone composite filler mass B (g) / particle density B (g / cm 3 ) = Volume B of silicone composite filler (cm 3 )...Equation (2) Silicone composite filler volume B (cm 3 ) / (Adhesive resin *1 Volume A (cm 3 ) + Silicone composite filler volume B (cm 3 )) × 100 = Volume fraction of silicone composite filler (volume %) Equation (3) In the above formulas (1) and (3), the adhesive resin represented by *1 may contain other components described below. The density is a value measured in accordance with JIS Z 8804.

[0031] The silicone composite filler in this embodiment may be a commercially available product or may be prepared by a known manufacturing method. The manufacturing method of the silicone composite filler in this embodiment is not particularly limited, and known methods can be adopted. For example, it can be produced according to the method described in JP-A-7-196815. That is, an alkaline substance or an alkaline aqueous solution and an organotrialkoxysilane are added to an aqueous dispersion of spherical rubber particles (e.g., spherical silicone rubber fine particles) having an average particle size of more than 2 μm and less than 40 μm, and the organotrialkoxysilane is hydrolyzed and polymerized on the surface of the spherical silicone rubber fine particles to prepare a silicone composite filler precursor, and then the precursor is dried to produce the desired silicone composite filler.

[0032] <Microballoons> The adhesive layer of the present embodiment contains microballoons. The microballoons in the adhesive layer have a number average primary particle size of 5 to 50 μm. Meanwhile, the microballoons used as the raw material for preparing the adhesive layer composition have an average particle size of 10 to 50 μm. When microballoons having a predetermined number-average primary particle size are present in the adhesive layer, a large number of cavities or shear yields occur near the microballoons dispersed in the matrix, absorbing the energy at the time of impact, which is thought to improve impact resistance. However, if the filling rate of the microballoons in the adhesive layer is increased with emphasis on the required impact resistance, the elastic modulus is improved and the cutting processability is improved, but the relative amount of the adhesive resin decreases and the adhesive performance is reduced. This tendency is particularly noticeable when an adhesive tape having an adhesive layer and a base layer is used, because poor anchoring of the adhesive layer to the base layer occurs. However, when the above-mentioned silicone composite filler and microballoons are added in combination to the adhesive layer, high adhesive strength can be maintained while ensuring impact resistance. Although the reason is unclear, it is thought that when a filler and microballoons of different particle sizes and materials are mixed, the aggregation of the fillers or balloons is suppressed, resulting in a good dispersion state of the adhesive layer.

[0033] The microballoons in this embodiment are hollow bodies, and the average particle size (=outer diameter) of the hollow bodies alone is 10 to 50 μm. The microballoons may contain volatile hydrocarbons such as butane and isobutane, if necessary. The average particle size (=outer diameter) of the hollow bodies (single body) of 10 to 50 μm here refers to the average particle size of the microballoons after they are expanded. When the microballoons in this embodiment are added to the adhesive layer composition, it is preferable to use expanded microballoons obtained by expanding unexpanded microballoons in advance by heat treatment or the like. In addition, when forming an adhesive layer precursor (such as a coating film of an adhesive layer resin composition) or an adhesive layer using unexpanded microballoons, the microballoons may be expanded. Examples of the unexpanded microballoons include unexpanded thermoplastic resin microballoons.

[0034] Similarly, the number average primary particle diameter of the microballoons present in the adhesive layer also represents the outer diameter of the microballoons after expansion. In this embodiment, the microballoons contained in the adhesive layer may be hollow bodies having a number average primary particle diameter of 5 to 50 μm, and are preferably expanded microballoons.

[0035] In this embodiment, the average particle size of the expanded microballoons added to the adhesive layer composition is preferably 10 to 50 μm, more preferably 15 to 50 μm, and even more preferably 18 to 45 μm. When the average particle size of the microballoons is within the preferred range, the adhesive tape can be peeled off more easily and quickly, and even if the thickness of the adhesive tape base material is thin, the adhesive tape is not easily torn, and has excellent impact resistance, shear adhesive strength, and cleavage adhesive strength. On the other hand, when the average particle size of the microballoons is less than 10 μm, the desired impact resistance cannot be obtained, and when it exceeds 50 μm, the adhesive performance such as shear adhesive strength and cleavage adhesive strength may be impaired. In this specification, the "average particle size of microballoons" refers to the size of the microballoons alone before they are added to the adhesive layer composition, and refers to the volume average particle size measured by a measuring device (Microtrack) using a laser diffraction scattering method. The average particle size of the microballoons was measured under the measurement conditions described in the Examples section below.

[0036] In this specification, the "number average primary average particle size of microballoons" refers to the size of a single microballoon particle present in the adhesive layer, and the number average primary average particle size of microballoons present in the adhesive layer is measured using the following method. First, the adhesive tape cooled under liquid nitrogen was cut at three random locations using a microtome, and the three pieces were used as samples. Then, a photograph was taken of each sample at a magnification of 400 times using a scanning electron microscope, and from the three photographs taken, the hollow particles were selected as microballoons and the solid particles were selected as silicone composite fillers. Then, the cross-sectional areas of the hollow and solid bodies calculated by binarization processing (for example, Otsu's binarization processing) using image analysis software were regarded as the area of ​​a circle, and the circle equivalent diameters of the hollow and solid bodies were measured. Then, the total number of hollow and solid bodies in the three photographs and the corresponding circle equivalent diameters were calculated, and the number average primary average particle size of the hollow microballoons was calculated from the following formula (B).

number

[0037] In this embodiment, the external shape of the microballoons is not particularly limited and can be appropriately selected depending on the purpose. Examples of the external shape of the microballoons include spherical, elliptical, polygonal, cubic, rod-like, needle-like, flat, scaly, and amorphous.

[0038] The microballoons in this embodiment have a structure sealed by a surface layer, which is an outer shell. Either microballoons using an organic material (e.g., thermoplastic resin) for the outer shell or microballoons using an inorganic material (e.g., borosilicate glass, silica, carbon, ceramic, etc.) for the outer shell can be used, but organic microballoons are preferred. When organic microballoons are used, the outer shell becomes soft, especially when heat is applied to the microballoons. At the same time, the liquid foaming agent gas or the like enclosed inside the hollow body changes to its gaseous state. At this time, the microballoons expand irreversibly and expand three-dimensionally. The expansion ends when the internal pressure and external pressure become equal. Since the outer shell is maintained, a closed-cell foam can be obtained.

[0039] In this embodiment, the microballoons contained in the adhesive layer are preferably expanded microballoons. In addition, in this embodiment, in the adhesive layer composition for forming the adhesive layer, unexpanded microballoons are used to form the adhesive layer. The unexpanded microballoons may be microballoons made of a thermoplastic resin that is not expanded. In this embodiment, the microballoons preferably have a surface layer, which is an outer shell, made of the first resin. More specifically, the preferred microballoons in this embodiment are hollow particles having a surface layer containing the first resin.

[0040] The first resin is preferably a thermoplastic resin, and is preferably an acrylonitrile resin, specifically, vinylidene chloride / acrylonitrile copolymer, methyl methacrylate / acrylonitrile copolymer, methacrylonitrile / acrylonitrile copolymer, etc. Specific examples of the microballoons include the Dualite (registered trademark) series manufactured by Dualite Corporation, the Expancel series manufactured by Akzo Nobel, the Matsumoto Microsphere (registered trademark) series manufactured by Matsumoto Yushi Pharmaceutical Co., Ltd., hollow glass particles (silica balloons, alumina balloons, etc.), hollow ceramic particles, etc.

[0041] In this embodiment, it is preferable that the surface of the microballoons is partially or entirely coated with an inorganic material (e.g., inorganic fine particles). The inorganic material is preferably at least one or more inorganic powders selected from the group consisting of calcium carbonate, surface-treated calcium carbonate, titanium oxide, silicon oxide, talc, clay, and carbon black. Coating the surface of the microballoons with an inorganic material is preferable from the viewpoint of improving productivity, dispersibility, and impact resistance. In addition, the inorganic material may be surface-treated with a titanate-based coupling agent or an aluminate-based coupling agent, if necessary. The microballoons used in this embodiment are hollow particles having a surface layer containing a first resin, and preferably have an inorganic material attached to the surface of the surface layer. In this embodiment, it is also preferable that calcium carbonate is attached to a part or the whole of the microballoon surface. This further improves the impact resistance effect.

[0042] In this embodiment, the ratio of the number average primary particle size of the microballoons to the average thickness of the adhesive layer is not particularly limited and can be appropriately selected depending on the purpose. The ratio of the number average primary particle size of the microballoons to the thickness of the adhesive layer, expressed as [number average primary particle size of the microballoons / average thickness of the adhesive layer], is preferably in the range of 0.1 to 1.0, more preferably 0.2 to 0.9, even more preferably 0.2 to 0.8, and particularly preferably 0.3 to 0.7. When the ratio is 0.1 or more, suitable impact resistance is easily obtained, and when the ratio is 1.0 or less, it is advantageous in that the adhesive properties such as shear adhesive strength and split adhesive strength are also more excellent.

[0043] The content of the microballoons in the adhesive layer is 1 to 25 parts by mass, preferably 2 to 25 parts by mass, more preferably 3 to 23 parts by mass, and even more preferably 4 to 20 parts by mass, relative to 100 parts by mass of the adhesive resin. By having the content of the microballoons be 1 part by mass or more relative to 100 parts by mass of the adhesive resin, it is possible to achieve both impact resistance and cuttability, or to ensure ease of peeling. In addition, by having the content of the microballoons be 50 parts by mass or less relative to 100 parts by mass of the adhesive resin, it is possible to prevent the adhesive layer from remaining on the adherend, the impact resistance from decreasing, and the shear adhesive strength or split adhesive strength from decreasing. The content of the microballoons in the adhesive layer can be appropriately adjusted when preparing the composition for the adhesive layer.

[0044] The volume ratio of the microballoons to the total volume of the adhesive layer is preferably 3 to 40 volume%, more preferably 5 to 35 volume%, even more preferably 8 to 30 volume%, and most preferably 10 to 30 volume%. When the volume ratio of the microballoons is 3 volume% or more, the adhesive tape can be peeled off more easily and quickly. When the volume ratio of the microballoons is 40 volume% or less, the adhesive layer can be prevented from remaining on the adherend, the impact resistance can be reduced, and the shear adhesive strength or split adhesive strength can be prevented.

[0045] In this specification, the volume ratio of the microballoons to the adhesive layer can be calculated from the following formulas (4) to (6). Adhesive Resin *1 Mass A (g) / Adhesive resin *1 Density A (g / cm 3 ) = Adhesive resin *1 Volume A (cm 3 )...Equation (4) Mass of microballoon B (g) / Density of microballoon B (g / cm 3 ) = Volume of microballoon B (cm 3 )...Equation (5) Microballoon volume B (cm3 ) / (Adhesive resin *1 Volume A (cm 3 ) + volume of microballoon B (cm 3 )) × 100 = Volume fraction of microballoons (volume%) Equation (6) In the above formulas (4) and (6), the adhesive resin represented by *1 may contain other components described below. The density is a value measured in accordance with JIS Z 8804.

[0046] <Acrylic modified silicone> In this embodiment, the adhesive layer may further contain an acrylic modified silicone. That is, the adhesive layer preferably contains a silicone composite filler having a number average primary particle diameter of 3 to 45 μm, microballoons having a number average primary particle diameter of 5 to 50 μm, an adhesive resin, and an acrylic modified silicone. On the other hand, the composition for adhesive layer forming the adhesive layer preferably contains a silicone composite filler, microballoons, an adhesive resin, and an acrylic modified silicone, and the silicone composite filler preferably uses particles having an average particle diameter of 10 to 40 μm, and the microballoons preferably uses particles having an average particle diameter of 10 to 50 μm. By containing an acrylic modified silicone in the adhesive layer or the composition for adhesive layer, the frictional force of the outer surface of the adhesive layer can be controlled. In addition, the acrylic modified silicone present on the adhesive surface reduces the frictional resistance, so that the adhesive force when the adhesive tape is stretched and peeled off can be effectively reduced. Therefore, even if the stretching direction of the adhesive tape is at a relatively large angle to the surface of the adherend, for example, a vertical direction (sometimes called "90° direction"), or even if the tape is stretched at a high speed, the adhesive tape can be peeled off more easily and quickly. If a filler such as acrylic-modified silicone is contained in the composition for adhesive layer, there is a risk that the addition of the filler will cause a decrease in adhesive performance. However, the acrylic-modified portion of the acrylic-modified silicone has affinity with the adhesive resin in the composition for adhesive layer or the adhesive layer, and the particles become swollen by incorporating the adhesive component in the composition or the adhesive layer, so that the elasticity of the composition for adhesive layer or the adhesive layer is easily maintained, and the decrease in adhesive performance of the adhesive tape can be suppressed.

[0047] In this embodiment, when the adhesive layer composition or the adhesive layer further contains an acrylic-modified silicone, or when the frictional force of the outer surface of the adhesive layer is in the range of 0.1 to 5.0 N, preferably in the range of 0.12 to 4.8 N, the adhesive tape preferably has a base layer. A preferred embodiment of the adhesive tape of this embodiment has a base layer and an adhesive layer on one or both sides of the base layer, and the adhesive layer preferably contains a silicone composite filler having a number average primary particle diameter of 3 to 45 μm, microballoons having a number average primary particle diameter of 5 to 50 μm, an adhesive resin, and an acrylic-modified silicone. Another preferred embodiment of the adhesive tape of this embodiment has a base layer and an adhesive layer on one or both sides of the base layer, and the adhesive layer is preferably formed from a composition for adhesive layer containing a silicone composite filler having an average particle diameter of 10 to 40 μm, microballoons having an average particle diameter of 10 to 50 μm, an adhesive resin, and an acrylic-modified silicone. In an adhesive tape having an adhesive layer and a base layer in contact with the adhesive layer, the silicone portion of the acrylic modified silicone provides sliding properties, and the acrylic modified silicone present on the adhesive surface to the base layer reduces frictional resistance, thereby effectively reducing adhesive strength. Therefore, when the adhesive tape is stretched and peeled, the adhesive tape can be peeled off more easily and quickly. In addition, in an adhesive tape having an adhesive layer and a base layer in contact with the adhesive layer, the presence of microballoons and silicone composite filler in the adhesive layer makes the adhesive layer more susceptible to elastic deformation, thereby improving impact resistance, and the acrylic-modified portion of the acrylic-modified silicone has affinity with the adhesive resin, thereby improving the cohesive strength of the adhesive layer and improving the holding power or cutting processability. The acrylic-modified silicone present in the adhesive layer in this embodiment exhibits high affinity to the coexisting adhesive resin, so that it may be difficult to determine the presence or absence of the acrylic-modified silicone and its content from the adhesive tape, which is the product. Therefore, as an alternative to determining the presence or absence of the acrylic-modified silicone and its content, for example, the adhesive layer in this embodiment may be specified to contain a silicone composite filler having a number average primary particle size of 3 to 45 μm, microballoons having a number average primary particle size of 5 to 50 μm, and an adhesive resin, and the frictional force of the outer surface of the adhesive layer is 0.1 to 0.5 N. In this embodiment, when the adhesive layer contains the acrylic-modified silicone, the frictional force of the surface of the adhesive layer tends to be low. In addition, when the frictional force of the adhesive layer is low, it has an effect of being easy to slip during 90° peeling, and peeling is facilitated. In this embodiment, the frictional force of the outer surface of the adhesive layer is preferably 0.1 to 5.0N, more preferably 0.3 to 4.0N, and even more preferably 0.5 to 3.0N. In this specification, the dynamic friction coefficient of the adhesive layer refers to the dynamic friction coefficient of the surface of the adhesive layer that comes into contact with the adherend (other than the base material layer), and the frictional force of the adhesive layer is measured by the test method described in the frictional force measurement explained in the Examples section below. More specifically, the frictional force of the outer surface of the adhesive layer in this specification refers to the frictional force against cotton canvas at 23° C., and is preferably 0.1 to 5.0N, more preferably 0.3 to 4.0N, and even more preferably 0.5 to 3.0N. In this embodiment, the outer surface of the adhesive layer refers to the surface that adheres to the adherend, in other words, the surface opposite the base layer side of the two opposing surfaces of the adhesive layer. In the adhesive tape of this embodiment, the friction force of at least one outer surface of the adhesive layer may be 0.1 to 5.0 N. In addition, the cotton canvas in this specification is made of cotton, and is No. 9 cotton canvas [(old JIS L3102 is applied), raw yarn twist (warp 10 / 2, weft 10 / 3), density (warp 44-48 threads / inch, weft 33-37 threads / inch), weight 510 g / m 2)] was used, and the friction force was measured in an atmosphere with a temperature of 23°C and a humidity of 50% RH.

[0048] In this embodiment, the acrylic-modified silicone may be an emulsion graft polymer of a polyorganosiloxane represented by the following general formula (I), an acrylic acid ester monomer and / or a methacrylic acid ester monomer, and a functional group-containing monomer copolymerizable therewith. [ka] (In the above general formula (I), R 1 and R 2 each independently represents a substituted or unsubstituted alkyl group having 1 to 20 carbon atoms or an aryl group having 6 to 20 carbon atoms; 1 , X 2 , X 3 , X 4 , X 5 , and X 6 each independently represents a substituted or unsubstituted alkyl group having 1 to 20 carbon atoms, an aryl group having 6 to 20 carbon atoms, an alkoxy group having 1 to 20 carbon atoms, or a hydroxyl group; Y 1 and Y 2 are each independently 1 or -[O-Si(X 7 )(X 8 )] c -X 9 represents a group represented by the formula: 7 , X 8 , and X 9 each independently represents a substituted or unsubstituted alkyl group having 1 to 20 carbon atoms, an aryl group having 6 to 20 carbon atoms, an alkoxy group having 1 to 20 carbon atoms, or a hydroxyl group; 1 , X 2 , X 3 , X 4 , X 5 , X 6 , X 7 , X 8 , and X 9 And Y 1 and Y 2at least two groups in the formula (1) are hydroxyl groups, and a, b, and c each independently represent a positive number satisfying 0≦a≦1,000, 100≦b≦10,000, and 1≦c≦1,000.

[0049] In the general formula (I), R 1 or R 2 The alkyl group having 1 to 20 carbon atoms represented by the formula (I) may be linear or branched, or may be cyclic. Specific examples include methyl, ethyl, propyl, butyl, pentyl, hexyl, heptyl, octyl, nonyl, decyl, dodecyl, tetradecyl, hexadecyl, octadecyl, cyclopentyl, cyclohexyl, and cycloheptyl. These alkyl groups may be substituted with a halogen atom, an acryloxy group, a methacryloxy group, a carboxy group, an alkoxy group, an alkenyloxy group, an amino group, or an alkyl, alkoxy, or (meth)acryloxy-substituted amino group.

[0050] R 1 or R 2 Examples of the aryl group having 6 to 20 carbon atoms represented by the formula (R) include a phenyl group, a tolyl group, and a naphthyl group. 1 or R 2 is preferably a methyl group. In the general formula (I), X 1 ~X 9 As the alkyl group having 1 to 20 carbon atoms and the aryl group having 6 to 20 carbon atoms represented by the formula: 1 or R 2 Examples of the alkyl and aryl groups are the same as those exemplified above.

[0051] X 1 ~X 9 Examples of the alkoxy group having 1 to 20 carbon atoms represented by the formula (I) include a methoxy group, an ethoxy group, a propoxy group, a butoxy group, a hexyloxy group, a heptyloxy group, an octyloxy group, a decyloxy group, and a tetradecyloxy group.

[0052] In the general formula (I), a, b, and c are positive numbers of 0≦a≦1,000, 100≦b≦10,000, and 1≦c≦1,000, but a is preferably a positive number of 0 to 200. If a is greater than 1,000, the strength of the resulting film is insufficient. b is preferably a positive number of 1,000 to 5,000. If b is less than 100, the film will have poor flexibility, and if it is greater than 10,000, it will be difficult to form a solid like particles. c is preferably a positive number of 1 to 200. Moreover, the polyorganosiloxane represented by general formula (I) has at least two, and preferably 2 to 4, hydroxyl groups in one molecule from the viewpoint of crosslinkability, and the hydroxyl groups are preferably located at both ends of the molecular chain. Examples of the acrylic acid ester monomer or methacrylic acid ester monomer used in the acrylic-modified silicone include methyl acrylate, ethyl acrylate, isopropyl acrylate, n-butyl acrylate, methyl methacrylate, ethyl methacrylate, isopropyl methacrylate, and cyclohexyl methacrylate.

[0053] Examples of functional group-containing monomers copolymerizable with the acrylic acid ester monomers and / or methacrylic acid ester monomers include monomers having unsaturated bonds including carboxyl groups, amide groups, hydroxyl groups, vinyl groups, allyl groups, and the like.

[0054] The acrylic-modified silicone in this embodiment is preferably obtained by mixing 10 to 100 parts by mass of an acrylic acid ester monomer and / or a methacrylic acid ester monomer, and 0.01 to 20 parts by mass of a functional group-containing monomer copolymerizable therewith, with respect to 100 parts by mass of the polyorganosiloxane represented by the above general formula (I), and subjecting the mixture to emulsion graft polymerization. The conditions for emulsion graft polymerization are not particularly limited, and as the initiator used during polymerization, a known radical initiator that is usually used for acrylic polymers can be used. Also, as the emulsifier, a known anionic surfactant or nonionic surfactant can be used.

[0055] The acrylic-modified silicone usable in the adhesive layer composition in this embodiment may be in a form containing a polymer in which a part of the polyorganosiloxane is modified by a (meth)acrylic monomer, and is not particularly limited to any of solid, powder, particulate, and solution forms. The shape of the acrylic-modified silicone usable in the adhesive layer composition in this embodiment is not particularly limited and can be appropriately selected according to the purpose, and may be a regular shape or an irregular shape. Specific examples of acrylic-modified silicone in the form of particles include polygonal, cubic, elliptical, spherical, needle-like, flat, and scale-like shapes, and among these, the particle shape is preferably elliptical, spherical, or polygonal, and more preferably spherical. When the particle shape is elliptical, spherical, polygonal, or the like, the adhesive layer slides well against the adherend when the adhesive tape is stretched, and the adhesive tape can be peeled off more easily and quickly. Particles of these shapes may be used alone or in combination of two or more types. Furthermore, when granular acrylic modified silicone is used, the average particle size of the acrylic modified silicone is preferably 10 to 400 μm, and more preferably 15 to 400 μm. When a granular acrylic modified silicone is used as the acrylic modified silicone of this embodiment, it is granulated and powdered by the following method. That is, spray drying, air flow drying, etc. are included, but a spray dryer is preferable from the viewpoint of productivity. Powdering is preferably performed by hot drying, and processing is preferably performed at 80 to 150°C. Examples of acrylic-modified silicones that can be used in this embodiment include commercially available products such as Charine R-170, Charine R-170S, Charine R-770, Charine R-773, and Charine R-200 (all manufactured by Nissin Chemical Industry Co., Ltd.).

[0056] In this embodiment, the content of the acrylic-modified silicone in the adhesive layer composition is 0.1 to 10 parts by mass, preferably 0.3 to 8 parts by mass, more preferably 0.5 to 5 parts by mass, and even more preferably 1.0 to 5 parts by mass, relative to 100 parts by mass of the adhesive resin. When the content of the particles is 0.1 parts by mass or more relative to 100 parts by mass of the adhesive resin, the adhesive tape can be peeled off more easily and quickly. Furthermore, when the content of the particles is 10 parts by mass or less relative to 100 parts by mass of the adhesive resin, it is possible to prevent the impact resistance from being deteriorated and the shear adhesive strength or the split adhesive strength from being weakened. Furthermore, the content of the acrylic-modified silicone in the adhesive layer can be within the same range as above. The content of the acrylic-modified silicone in the adhesive layer can be appropriately adjusted when preparing the composition for the adhesive layer. In the present embodiment, the acrylic-modified silicone preferably does not substantially contain silicone particles composed only of polyorganosiloxane.

[0057] <Adhesive resin> The adhesive resin in this embodiment is not particularly limited and can be appropriately selected from known substances, and examples thereof include acrylic adhesive resins, rubber adhesive resins, and other adhesive resins (e.g., urethane adhesive resins, silicone adhesive resins, mixed adhesives, etc.). These may be used alone or in combination of two or more. Among these, from the viewpoint of achieving both excellent physical properties as an adhesive tape, such as impact resistance, and processability, it is preferable that the adhesive resin contains an acrylic adhesive resin. In this embodiment, the adhesive resin is preferably contained in an amount of 30 to 90 mass % relative to the total amount (100 mass %) of the adhesive layer, more preferably 35 to 80 mass %, and even more preferably 40 to 70 mass %. When the adhesive resin is contained in the adhesive layer in the above range, the adhesive strength is maintained and the ease of peeling or removal is further exhibited.

[0058] <<Acrylic adhesive resin>> The acrylic adhesive resin is not particularly limited and can be appropriately selected depending on the purpose. For example, it can be an acrylic polymer. If necessary, additives such as a tackifier resin (a1), a crosslinking agent, or optional components of the adhesive layer may be added to the adhesive layer or a composition for the adhesive layer.

[0059] Acrylic polymers can be produced, for example, by polymerizing (meth)acrylate monomers. As the (meth)acrylate monomer, for example, an alkyl (meth)acrylate having an alkyl group having 1 to 12 carbon atoms can be used. Specific examples of alkyl (meth)acrylates having an alkyl group having 1 to 12 carbon atoms include methyl (meth)acrylate, ethyl (meth)acrylate, n-butyl (meth)acrylate, isobutyl (meth)acrylate, t-butyl (meth)acrylate, n-hexyl (meth)acrylate, n-octyl (meth)acrylate, isooctyl (meth)acrylate, isononyl (meth)acrylate, cyclohexyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, etc. These may be used alone or in combination of two or more.

[0060] As the alkyl (meth)acrylate having an alkyl group with 1 to 12 carbon atoms, it is preferable to use an alkyl (meth)acrylate having an alkyl group with 4 to 12 carbon atoms, more preferably an alkyl (meth)acrylate having an alkyl group with 4 to 8 carbon atoms, and it is particularly preferable to use n-butyl acrylate in order to ensure excellent adhesion to the adherend.

[0061] The alkyl (meth)acrylate having an alkyl group having 1 to 12 carbon atoms is preferably used in the range of 80 to 98.5 mass %, more preferably 90 to 98.5 mass %, based on the total amount of monomers used in the production of the acrylic polymer.

[0062] As the monomers usable in the production of the acrylic polymer, in addition to the above-mentioned ones, highly polar vinyl monomers can be used as necessary. Examples of highly polar vinyl monomers include (meth)acrylic monomers such as (meth)acrylic monomers having a hydroxyl group, (meth)acrylic monomers having a carboxyl group, and (meth)acrylic monomers having an amide group, as well as sulfonic acid group-containing monomers such as vinyl acetate, ethylene oxide-modified succinic acid acrylate, and 2-acrylamido-2-methylpropanesulfonic acid. These may be used alone or in combination of two or more.

[0063] Specific examples of vinyl monomers having a hydroxyl group include (meth)acrylic monomers such as 2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, 4-hydroxybutyl (meth)acrylate, and 6-hydroxyhexyl (meth)acrylate.

[0064] It is preferable to use a vinyl monomer having a hydroxyl group when a pressure-sensitive adhesive resin containing an isocyanate-based crosslinking agent is used. Specifically, it is preferable to use 2-hydroxyethyl (meth)acrylate, 4-hydroxybutyl (meth)acrylate, or 6-hydroxyhexyl (meth)acrylate as the vinyl monomer having a hydroxyl group.

[0065] The vinyl monomer having a hydroxyl group is preferably used in an amount of 0.01 to 1.0 mass %, more preferably 0.03 to 0.3 mass %, based on the total amount of monomers used in the production of the acrylic polymer.

[0066] Specific examples of vinyl monomers having a carboxyl group include (meth)acrylic monomers such as acrylic acid, methacrylic acid, itaconic acid, maleic acid, (meth)acrylic acid dimer, crotonic acid, and ethylene oxide-modified succinic acid acrylate. Among these, acrylic acid is preferred.

[0067] Specific examples of vinyl having an amide group include (meth)acrylic monomers such as N-vinylpyrrolidone, N-vinylcaprolactam, acryloylmorpholine, acrylamide, and N,N-dimethylacrylamide.

[0068] The highly polar vinyl monomer is preferably used in the range of 1.5% by mass to 20% by mass, more preferably 1.5% by mass to 10% by mass, and even more preferably 2% by mass to 8% by mass, relative to the total amount of monomers used in the production of the acrylic polymer, since this allows for the formation of an adhesive layer that is well balanced in terms of cohesive strength, holding power, and adhesiveness.

[0069] The method for producing the acrylic polymer is not particularly limited and may be appropriately selected from known methods depending on the purpose, and examples thereof include a method in which a monomer is polymerized by a polymerization method such as a solution polymerization method, a bulk polymerization method, a suspension polymerization method, an emulsion polymerization method, etc. Among these, it is preferable to produce the acrylic polymer by the solution polymerization method or the bulk polymerization method.

[0070] When polymerizing the acrylic polymer, a peroxide-based thermal polymerization initiator such as benzoyl peroxide or lauroyl peroxide, an azo thermal polymerization initiator such as azobisisobutylnitrile, an acetophenone-based photopolymerization initiator, a benzoin ether-based photopolymerization initiator, a benzyl ketal-based photopolymerization initiator, an acylphosphine oxide-based photopolymerization initiator, a benzoin-based photopolymerization initiator, a benzophenone-based photopolymerization initiator, or the like can be used, as necessary. In the present embodiment, the acrylic polymer may be a homopolymer or a multicomponent copolymer (a di- to hepta-component copolymer), or may be a mixture thereof.

[0071] The weight-average molecular weight of the acrylic polymer obtained by the above method is preferably 300,000 to 3,000,000, and more preferably 500,000 to 2,500,000, as measured using gel permeation chromatography (GPC) and converted into standard polystyrene.

[0072] Here, the weight average molecular weight of the acrylic polymer is measured by the GPC method using a GPC apparatus (HLC-8329GPC, manufactured by Toso Corporation) and is expressed as a standard polystyrene equivalent value. The measurement conditions are as follows. [Measurement conditions] Sample concentration: 0.5% by mass (tetrahydrofuran (THF) solution) Sample injection volume: 100μL · Eluent: THF · Flow rate: 1.0mL / min · Measurement temperature: 40℃ - Column: TSKgel GMHHR-H(20) x 2 Guard column: TSKgel HXL-H Detector: Differential refractometer Standard polystyrene molecular weight: 10,000 to 20 million (Tosoh Corporation)

[0073] In this embodiment, the acrylic polymer is preferably a triblock copolymer represented by the following general formula (II) or a diblock copolymer represented by the following general formula (III): Preferred aspects of the acrylic polymer in this embodiment will be described below.

[0074] --Triblock copolymer-- The adhesive layer of the adhesive tape of the present embodiment is a compound represented by the following general formula (II): [ka] (In the above general formula (II), A, B, and C each independently represent a repeating unit, A and C each independently represent a methacrylic acid alkyl ester monomer unit, B represents an acrylic acid alkyl ester monomer unit, p, q, and r each independently represent the degree of polymerization of each monomer unit, and A and C may be methacrylic acid alkyl ester monomer units having the same or different chemical structures. In the above general formula (II), * represents a bond to another atom.)

[0075] In the above general formula (II), A and C represent repeating units different from B, and represent methacrylic acid alkyl ester monomer units. A and C are each independent and may be the same methacrylic acid alkyl ester monomer units or methacrylic acid alkyl ester monomer units having different chemical structures. In this specification, the term "methacrylic acid alkyl ester monomer unit" refers to a structural unit derived from a methacrylic acid alkyl ester monomer when a methacrylic acid alkyl ester monomer is (co)polymerized or graft polymerized, that is, a repeating unit derived from a methacrylic acid ester monomer. In the present invention, the methacrylic acid alkyl ester monomer unit is represented by the following general formula (i): [ka] (In the above general formula (i), R i represents an alkyl group having 1 to 12 carbon atoms, and one or more hydrogen atoms in the alkyl group are each independently selected from the group consisting of a substituent R ii and the substituent R ii represents a halogen atom, an amino group, or a cyano group.

[0076] In the above general formula (i), R i From the viewpoint of removability and high load retention, R is more preferably an alkyl group having 1 to 12 carbon atoms, and even more preferably an alkyl group having 1 to 4 carbon atoms. iThe alkyl group having 1 to 12 carbon atoms may be linear, branched, or cyclic, and from the viewpoint of adhesive strength, linear or branched is preferable, and linear is more preferable. Examples of the alkyl group having 1 to 12 carbon atoms include linear or branched alkyl groups such as methyl, ethyl, propyl, isopropyl, n-butyl, isobutyl, t-butyl, n-pentyl, isopentyl, hexyl, octyl, nonyl, decyl, undecyl, and dodecyl, as well as cyclic alkyl groups such as cyclohexyl, cycloheptyl, cyclooctyl, cyclononyl, cyclodecyl, and dicyclopentanyl. Examples of the alkyl group having 1 to 4 carbon atoms include linear or branched alkyl groups such as methyl, ethyl, propyl, isopropyl, n-butyl, isobutyl, and t-butyl, as well as cyclic alkyl groups such as cyclobutyl. As the alkyl group having 1 to 4 carbon atoms, from the viewpoints of removability and high load retention, a methyl group, an ethyl group, a propyl group, an isopropyl group, an n-butyl group, an isobutyl group, and a t-butyl group are preferable, and a methyl group is more preferable.

[0077] Preferred R in the above general formula (i) i is any one of an alkyl group such as a methyl group, an ethyl group, a propyl group, an isopropyl group, an n-butyl group, an isobutyl group, a t-butyl group, or a cyclobutyl group, and one or more hydrogen atoms in the alkyl group are each independently selected from the group consisting of a substituent R 2 It may be substituted with (a halogen atom, an amino group, a cyano group).

[0078] In this embodiment, for example, the methacrylic acid alkyl ester monomer is not particularly limited, and examples thereof include methyl methacrylate, ethyl methacrylate, n-propyl methacrylate, isopropyl methacrylate, n-butyl methacrylate, isobutyl methacrylate, sec-butyl methacrylate, t-butyl methacrylate, n-pentyl methacrylate, isopentyl methacrylate, n-hexyl methacrylate, 2-ethylhexyl methacrylate, pentadecyl methacrylate, cyclohexyl methacrylate, lauryl methacrylate, tridecyl methacrylate, 2-hexyldecyl methacrylate, etc. Among these, methyl methacrylate is preferred from the viewpoints of high load retention and dismantling property (ease of peeling or removal).

[0079] In the above general formula (II), B represents a repeating unit different from A and C, and represents an acrylic acid alkyl ester monomer unit. In this specification, the term "acrylic acid alkyl ester monomer unit" refers to a structural unit derived from an acrylic acid alkyl ester monomer when an acrylic acid alkyl ester monomer is (co)polymerized or graft polymerized, i.e., a repeating unit derived from an acrylic acid ester monomer. In the present invention, the acrylic acid alkyl ester monomer unit is represented by the following general formula (ii): [ka] (In the above general formula (ii), R iii represents an alkyl group having 1 to 12 carbon atoms, and one or more hydrogen atoms in the alkyl group are each independently selected from the group consisting of a substituent R iv and the substituent R iv represents a halogen atom, an amino group, or a cyano group.

[0080] In the above general formula (ii), R iii From the viewpoint of adhesiveness, an alkyl group having 1 to 12 carbon atoms is more preferable, and an alkyl group having 4 to 8 carbon atoms is even more preferable. The alkyl group may be linear, branched, or cyclic, and from the viewpoint of adhesiveness, a linear or branched alkyl group is preferable.

[0081] In addition, in the above general formula (ii), examples of the alkyl group having 1 to 12 carbon atoms are the same as the examples of the alkyl group having 1 to 12 carbon atoms in the above general formula (i).

[0082] Preferred R in the above general formula (ii) iii is an alkyl group selected from the group consisting of n-butyl, isobutyl, t-butyl, n-pentyl, isopentyl, hexyl, octyl, cyclohexyl, cycloheptyl, and cyclooctyl, and one or more hydrogen atoms in the alkyl group are each independently selected from the group consisting of a substituent R iv It may be substituted with (a halogen atom, an amino group, a cyano group).

[0083] In this embodiment, examples of the acrylic acid alkyl ester monomer include methyl acrylate, ethyl acrylate, n-propyl acrylate, isopropyl acrylate, n-butyl acrylate, isobutyl acrylate, sec-butyl acrylate, t-butyl acrylate, amyl acrylate, isoamyl acrylate, n-hexyl acrylate, 2-ethylhexyl acrylate, lauryl acrylate, etc. Among these, from the viewpoint of achieving both adhesive strength and removability, n-butyl acrylate, 2-ethylhexyl acrylate, and copolymers thereof are preferred.

[0084] In the above general formula (II), p, q, and r each independently represent the degree of polymerization of each monomer unit. The values ​​of p, q, and r relate to the molecular weight, etc. p / (p+q+r) is preferably 0.02 to 0.40, and more preferably 0.05 to 0.37. q / (p+q+r) is preferably 0.20 to 0.95, and more preferably 0.25 to 0.90. r / (p+q+r) is preferably 0.02 to 0.40, and more preferably 0.05 to 0.37.

[0085] In this embodiment, the triblock copolymer has the following general formula (IV): [ka] (In the above general formula (IV), R i and R v each independently represents an alkyl group having 1 to 4 carbon atoms, and one or more hydrogen atoms in the alkyl group are each independently selected from the group consisting of a substituent R ii may be substituted with, and the substituent R ii represents a halogen atom, an amino group, or a cyano group, R iii represents an alkyl group having 4 to 8 carbon atoms, and one or more hydrogen atoms in the alkyl group are each independently selected from the group consisting of a substituent R iv may be substituted with, and the substituent R iv represents a halogen atom, an amino group, or a cyano group, and p, q, and r each independently represent the degree of polymerization of each monomer unit.

[0086] In the above general formula (IV), R i is R in the above general formula (i). i In the above general formula (IV), R iii is R in the above general formula (ii). iii In the above general formula (IV), R v is R in the above general formula (i). i In the above general formula (IV), p, q, and r can be the same as p, q, and r in the above general formula (II). i and R v may be the same or different.

[0087] In this embodiment, when the triblock copolymer is represented by the above general formula (IV), R i is preferably selected from the group consisting of linear or branched alkyl groups such as methyl, ethyl, propyl, isopropyl, n-butyl, isobutyl, and t-butyl, and a cyclobutyl group; R iiiis preferably selected from the group consisting of methyl, ethyl, propyl, isopropyl, n-butyl, isobutyl, t-butyl, n-pentyl, isopentyl, hexyl, octyl, nonyl, decyl, or undecyl; R v is preferably selected from the group consisting of linear or branched alkyl groups, such as a methyl group, an ethyl group, a propyl group, an isopropyl group, an n-butyl group, an isobutyl group, a t-butyl group, and the like, and a cyclobutyl group, and it is preferable that p / (p+q+r) is 0.02 to 0.40, q / (p+q+r) is 0.20 to 0.95, and r / (p+q+r) is 0.02 to 0.40.

[0088] In the triblock copolymer of the present invention, it is preferable that A and C in the general formula (II) are the same. Specifically, when the triblock copolymer has a repeating unit represented by the above general formula (IV), R i and R iii and are the same group, p / (p+q+r) is 0.02 to 0.40, q / (p+q+r) is 0.20 to 0.95, and r / (p+q+r) is 0.02 to 0.40. In the triblock copolymer having the repeating unit represented by the above general formula (II), when A and C are the same (ABA type triblock copolymer), a higher elastic modulus can be ensured, and therefore it is easier to ensure adhesive strength with excellent high load retention, removability over time, and storage stability.

[0089] The triblock copolymer in this embodiment preferably has a weight average molecular weight Mw of 50,000 to 300,000, and a number average molecular weight Mn of 50,000 to 300,000. More preferably, the triblock copolymer has a weight average molecular weight Mw of 100,000 to 250,000 and a number average molecular weight Mn of 100,000 to 250,000, and even more preferably, the triblock copolymer has a weight average molecular weight Mw of 130,000 to 230,000 and a number average molecular weight Mn of 130,000 to 230,000. It is preferable that the weight average molecular weight Mw of the triblock copolymer is within the above range from the viewpoints of adhesion, removability and high load retention, and it is preferable that the number average molecular weight Mn of the triblock copolymer is within the above range from the viewpoints of adhesion, removability and high load retention. Here, the weight average molecular weight Mw and number average molecular weight Mn of the triblock polymer are measured by the GPC method using a GPC apparatus (HLC-8329GPC, manufactured by Toso Corporation) and are values ​​converted into standard polystyrene. The measurement conditions are as follows: -Measurement conditions- Sample concentration: 0.5% by mass (tetrahydrofuran (THF) solution) Sample injection volume: 100μL · Eluent: THF · Flow rate: 1.0mL / min · Measurement temperature: 40℃ - Column: TSKgel GMHHR-H(20) x 2 Guard column: TSKgel HXL-H Detector: Differential refractometer Standard polystyrene molecular weight: 10,000 to 20 million (Tosoh Corporation)

[0090] The triblock copolymer of the present embodiment and / or a partial structure (e.g., a block) of the triblock copolymer preferably has stereoregularity (tacticity). Specifically, the triblock copolymer and / or a partial structure (e.g., a block) of the triblock copolymer may have any of isotactic, syndiotactic, and atactic stereoregularity, or may have a plurality of blocks having any of these stereoregularities.

[0091] A preferred embodiment of the triblock copolymer is represented by the general formula (II) "-(A) p The syndiotacticity of the polymer block in the -" portion preferably exhibits a ratio of rr triads of 65% or more, and more preferably the ratio of rr triads is 75 to 95%. A preferred embodiment of the triblock copolymer is represented by the formula (II) "-(C) r The syndiotacticity of the polymer block in the -" portion preferably exhibits a ratio of rr triads of 65% or more, and more preferably the ratio of rr triads is 75 to 95%. A preferred embodiment of the triblock copolymer is represented by the general formula (II) "-(B) q The polymer block of the -" portion preferably exhibits atacticity.

[0092] The triblock copolymer has a ratio of rr triads of 65% or more "-(A) p When the adhesive contains a polymer block of the -" portion, the adhesive exhibits good removability and retention at high temperatures.

[0093] Generally, the syndiotacticity of a polymer is expressed by the ratio of rr to rr in a chain (a triad) composed of three monomer units. In this specification, it is calculated by NMR measurement of the polymer. Specifically, 13 The signal peaks that represent the arrangement of triads in C-NMR vary depending on the type of polymer, the measurement solvent, the measurement temperature, and other conditions, so it is necessary to identify and quantify the signals according to the respective measurement conditions. In this specification, the samples dissolved in deuterated chloroform are measured at 50°C.

[0094] Preferred forms of the triblock copolymer include polymethyl methacrylate block-polyn-butyl acrylate block-polymethyl methacrylate, polyethyl methacrylate block-polyn-butyl acrylate block-polyethyl methacrylate, polypropyl methacrylate block-polyn-butyl acrylate block-polypropyl methacrylate, polymethyl methacrylate block-polyt-butyl acrylate block-polymethyl methacrylate, polymethyl methacrylate block-polypropyl acrylate block-polymethyl methacrylate, and the like.

[0095] The triblock copolymer has an overall molecular weight distribution, in terms of the ratio of weight average molecular weight / number average molecular weight, preferably in the range of 1.0 to 2.3, and more preferably in the range of 1.00 to 1.50.

[0096] In the present embodiment, when A and C in the general formula (II) are different repeating units, the "-(A) p Total weight of polymer blocks of "-" part (of the "-(A) p The total weight of the polymer blocks in the "-" part is referred to as a. q Total weight of polymer blocks of "-" part (said "-(B) q The total weight of the polymer blocks in the "-" portion is referred to as b. From the viewpoint of adhesive properties, the mass ratio of a / b is preferably within the range of 2 / 98 to 67 / 33, and more preferably within the range of 5 / 95 to 60 / 40.

[0097] In the present embodiment, when A and C in the general formula (II) are different repeating units, the "-(C)" contained in the molecule of the triblock copolymer r Total weight of polymer blocks of "-" part (relevant "-(C) r The total weight of the polymer blocks of "-" part is referred to as c. q From the viewpoint of adhesive properties, the ratio of the "-" portion to the total weight of the polymer blocks, c / b, is preferably within the range of 2 / 98 to 67 / 33, and more preferably within the range of 5 / 95 to 60 / 40, in terms of the mass ratio.

[0098] In the present embodiment, when A and C in the general formula (II) are the same repeating unit, the "-(A)" contained in the molecule of the triblock copolymer p The polymer block of the -" part and the -(C) r - Total weight of polymer blocks in "-" part ("-(A) p The polymer block of the -" part and the -(C) r The total weight of the polymer blocks in the "-" part is referred to as d. qFrom the viewpoint of adhesive properties, the ratio of the "-" portion to the total weight of the polymer blocks (referred to as b) is preferably within the range of 5 / 95 to 80 / 20, and more preferably within the range of 10 / 90 to 75 / 25, in terms of the mass ratio d / b.

[0099] The triblock copolymer may be modified, if necessary, with a functional group such as a hydroxyl group, a carboxyl group, an acid anhydride group, an amino group, or a trimethoxysilyl group in the molecular side chain or at the molecular main chain terminal, as long as the effect of the present invention is not impaired.

[0100] The method for producing the triblock copolymer is not particularly limited and can be appropriately selected from conventionally known production methods, for example, a method for sequentially polymerizing a block copolymer by an anionic living polymerization method, a cationic living polymerization method, etc. In addition, when the triblock copolymer has stereoregularity (for example, syndiotacticity), a known method using an organometallic complex may be used.

[0101] As an example of a method for producing the triblock copolymer, the triblock copolymer can be produced by a technique comprising sequentially polymerizing a methacrylic acid alkyl ester monomer as a main component and a monomer mainly composed of an acrylic acid alkyl ester monomer and / or a methacrylic acid alkyl ester monomer as a main component in an inert polymerization solvent using a polymerization initiator so as to obtain a desired block bonding order.

[0102] In the present embodiment, one aspect of the method for producing the triblock copolymer is to first polymerize a methacrylic acid alkyl ester monomer in a polymerization solvent using a polymerization initiator by an anionic living polymerization method to obtain a polymethacrylic acid alkyl ester block having a living active end ("-(A)" in general formula (II) pSecondly, an alkyl methacrylate-alkyl acrylate diblock copolymer having a living active end (corresponding to the "-(A)" portion in general formula (II)) is formed by polymerizing an alkyl acrylate monomer from the living active end of the polyalkyl methacrylate. p -(B) q Thirdly, a part of the alkyl methacrylate-alkyl acrylate diblock copolymer having a living active end is reacted with a coupling agent to obtain a coupled alkyl methacrylate-alkyl acrylate-alkyl methacrylate triblock copolymer (corresponding to the "-(A)" part of general formula (II)). p -(B) q -(C) r - In this case, the polymerization is terminated by reacting with a polymerization terminator such as alcohol, if necessary.

[0103] Examples of the polymerization initiator include organolithium compounds and organometallic compounds such as organolithium compounds and organometallic complexes. Examples of the organolithium compound include alkyllithium such as t-butyllithium, and compounds obtained by reacting alkyllithium with 1,1-diphenylethylene, diphenylmethane, etc. Furthermore, these organolithium compounds may be used in combination with inorganic salts such as lithium chloride, lithium salts of alkoxides such as lithium 2-(2-methoxyethoxy)ethoxide, and organoaluminum compounds such as diisobutyl(2,6-di-t-butyl-4-methylphenoxy)aluminum. The above-mentioned organometallic complexes include rare earth metal complexes having a pentamethylcyclopentadienyl group as a ligand, such as bis(pentamethylcyclopentadienyl)samarium methyltetrahydrofuranate, bis(pentamethylcyclopentadienyl)yttrium methyltetrahydrofuranate, etc. Furthermore, these organometallic complexes may be used in combination with alkylaluminums such as trimethylaluminum.

[0104] Examples of the polymerization solvent that can be used include hydrocarbon solvents such as benzene, toluene, and xylene; halogenated hydrocarbon solvents such as chloroform, methylene chloride, and carbon tetrachloride; and ether solvents such as tetrahydrofuran and diethyl ether. In the adhesive layer of the present embodiment, the triblock copolymer preferably accounts for 50 to 100 mass % of the entire adhesive resin, and more preferably 70 to 100 mass % of the triblock copolymer. When the content of the triblock copolymer in the adhesive resin used in the adhesive layer is within the above range, it is easy to achieve both adhesiveness, dismantling ability, and high load retaining strength.

[0105] --Diblock copolymer-- The adhesive layer of the adhesive tape of the present embodiment is a compound represented by the following general formula (III): [ka] (In the above general formula (III), D and E each independently represent a repeating unit, D represents a methacrylic acid alkyl ester monomer unit, E represents an acrylic acid alkyl ester monomer unit, and s and t each independently represent the degree of polymerization of each monomer unit. In the above general formula (III), * represents a bond to another atom.) In the adhesive layer of the adhesive tape of this embodiment, the diblock copolymer preferably accounts for 0 to 40 mass %, more preferably 0 to 20 mass %, of the entire adhesive resin. When the content of the diblock copolymer in the adhesive resin used in the adhesive layer is within the above range, it is easy to achieve both adhesiveness, dismantling ability, and high load retaining strength.

[0106] In addition, in this embodiment, when a triblock copolymer and a diblock copolymer are used in combination as the adhesive resin, it becomes easier to ensure high elastic modulus and initial adhesion, and therefore it becomes easier to ensure high load retention, removability over time, and initial adhesion. In particular, when the adhesive tape is pulled, the filler or microballoons in the adhesive layer can be maintained in a state exposed to the surface for a long period of time, and this, combined with the effect of the filler, produces an excellent synergistic effect.

[0107] The methacrylic acid alkyl ester monomer unit and the acrylic acid alkyl ester monomer unit in the above general formula (III) can have the same form as the methacrylic acid alkyl ester monomer unit and the acrylic acid alkyl ester monomer unit in the above general formula (II). The diblock copolymer has the following general formula (V): [ka] (In the above general formula (V), R a represents an alkyl group having 1 to 12 carbon atoms, and one or more hydrogen atoms in the alkyl group are each independently selected from the group consisting of a substituent R c and the substituent R c represents a halogen atom, an amino group, or a cyano group; R b represents an alkyl group having 1 to 12 carbon atoms, and one or more hydrogen atoms in the alkyl group are each independently selected from the group consisting of a substituent R d and the substituent R d represents a halogen atom, an amino group, or a cyano group, and s and t each independently represent the degree of polymerization of each monomer unit.

[0108] In the above general formula (V), R a is R in the above general formula (i). i In the above general formula (V), R b is R in the above general formula (ii). iii In the above general formula (V), s and t can have the same configuration as p and q in the above general formula (II).

[0109] In this embodiment, the diblock copolymer preferably has a weight average molecular weight Mw of 50,000 to 300,000 and a number average molecular weight Mn of 50,000 to 300,000. The weight average molecular weight can be measured using the method for measuring the weight average molecular weight of the triblock copolymer in the present invention.

[0110] In the above general formula (V), s and t each independently represent the degree of polymerization of each monomer unit. The values ​​of s and t relate to the molecular weight, etc. s / (s+t) is preferably 0.01 to 0.99, more preferably 0.1 to 0.9. t / (s+t) is preferably 0.01 to 0.99, more preferably 0.1 to 0.9.

[0111] In the present embodiment, when a diblock copolymer and a triblock copolymer are used in combination, the content of the diblock copolymer is not particularly limited and can be appropriately selected according to the purpose. In the present embodiment, the diblock copolymer is preferably contained in an amount of 0 to 100 parts by mass, more preferably 1 to 50 parts by mass, and even more preferably 10 to 50 parts by mass, per 100 parts by mass of the triblock copolymer. When the content of the adhesive resin in the adhesive layer is within the above range, adhesion to the adherend is easily ensured.

[0112] --Tackifier resin (a1)-- The acrylic pressure-sensitive adhesive resin in this embodiment is preferably used in combination with a tackifier resin (a1) in order to improve the adhesion to the adherend and the surface adhesive strength. The tackifier resin (a1) is not particularly limited and can be appropriately selected depending on the purpose, but a resin having a softening point of 30° C. to 180° C. is preferred, and a resin having a softening point of 70° C. to 140° C. is more preferred in terms of forming an adhesive layer with high adhesive performance. When a (meth)acrylate-based tackifier resin is used, it is preferred that the glass transition temperature is 30° C. to 200° C., and more preferably 50° C. to 160° C.

[0113] Specific examples of the tackifier resin (a1) in this embodiment include rosin-based tackifier resins, polymerized rosin-based tackifier resins, polymerized rosin ester-based tackifier resins, rosin phenol-based tackifier resins, stabilized rosin ester-based tackifier resins, disproportionated rosin ester-based tackifier resins, hydrogenated rosin ester-based tackifier resins, terpene-based tackifier resins, terpene phenol-based tackifier resins, petroleum resin-based tackifier resins, and (meth)acrylate-based tackifier resins. These tackifier resins may be used alone or in combination of two or more. Among these, the tackifier resin (a1) is preferably a polymerized rosin ester-based tackifier resin, a rosin phenol-based tackifier resin, a disproportionated rosin ester-based tackifier resin, a hydrogenated rosin ester-based tackifier resin, a terpene phenol-based resin, or a (meth)acrylate-based resin.

[0114] In this embodiment, the amount of the tackifier resin (a1) used is not particularly limited and can be appropriately selected according to the purpose. For example, the content of the tackifier resin (a1) is preferably 5 parts by mass to 65 parts by mass, and more preferably 8 parts by mass to 55 parts by mass, based on 100 parts by mass of the adhesive resin or acrylic polymer, because it is easy to ensure adhesion to the adherend.

[0115] In the present embodiment, when an acrylic adhesive resin is used as the tackifier resin, it is preferable to use one that contains a crosslinking agent in order to further improve the cohesive strength of the adhesive layer.

[0116] The crosslinking agent is not particularly limited and can be appropriately selected according to the purpose, and examples thereof include isocyanate-based crosslinking agents, epoxy-based crosslinking agents, metal chelate-based crosslinking agents, and aziridine-based crosslinking agents. These crosslinking agents may be used alone or in combination of two or more. Among them, crosslinking agents that are mixed with the acrylic polymer after production to promote a crosslinking reaction are preferred, and it is more preferred to use isocyanate-based crosslinking agents and epoxy-based crosslinking agents that are highly reactive with the acrylic polymer.

[0117] Examples of the isocyanate crosslinking agent include tolylene diisocyanate, triphenylmethane isocyanate, naphthylene-1,5-diisocyanate, hexamethylene diisocyanate, diphenylmethane diisocyanate, xylylene diisocyanate, and trimethylolpropane-modified tolylene diisocyanate. These may be used alone or in combination of two or more. Among these crosslinking agents, trifunctional polyisocyanate compounds such as tolylene diisocyanate and its trimethylolpropane adduct, and triphenylmethane isocyanate are particularly preferred.

[0118] In this embodiment, the gel fraction value obtained by measuring the insoluble portion after immersing the adhesive layer in toluene for 24 hours is used as an index of the degree of crosslinking. The gel fraction value of the adhesive layer is not particularly limited and can be appropriately selected according to the purpose. For example, the gel fraction value of the adhesive layer is preferably 10% by mass to 70% by mass, more preferably 25% by mass to 65% by mass, and even more preferably 35% by mass to 60% by mass in order to obtain an adhesive layer having both good cohesiveness and adhesiveness.

[0119] The gel fraction refers to a value measured by the following method. A composition for adhesive layer containing an adhesive resin and, if necessary, additives is applied to a release sheet so that the thickness after drying is 50 μm, dried at 100° C. for 3 minutes, aged at 40° C. for 2 days, and cut into a 50 mm square to be used as a sample. Next, the mass (G1) of the sample before immersion in toluene is measured in advance, and the toluene-insoluble portion of the sample after immersion in a toluene solution at 23° C. for 24 hours is separated by filtering with a 300 mesh wire net, and the mass (G2) of the residue after drying at 110° C. for 1 hour is measured, and the gel fraction is calculated according to the following formula (7). The mass (G3) of the conductive fine particles in the sample is calculated from the mass (G1) of the sample and the composition of the adhesive layer. Gel fraction (mass%) = (G2-G3) / (G1-G3) × 100 Formula (7)

[0120] The adhesive layer of the present embodiment preferably contains a triblock copolymer having a repeating unit represented by the above general formula (II) as an adhesive resin. If necessary, the adhesive layer may further contain a diblock copolymer, an acrylic adhesive resin, a rubber adhesive resin, or other adhesive resins as an adhesive resin other than the triblock copolymer. In addition, the adhesive layer of the present embodiment may contain a copolymer having the general formula ( It may contain the diblock copolymer represented by II), an acrylic adhesive resin, a rubber adhesive resin or other adhesive resins.

[0121] <<Rubber-based adhesive resin>> The rubber-based adhesive resin usable in the adhesive layer of the present embodiment is not particularly limited, and examples thereof include rubber materials that can be generally used as adhesive resins (e.g., synthetic rubber-based adhesive resins or natural rubber-based adhesive resins, etc.). The rubber material may contain additives such as a tackifier resin (a2) as necessary.

[0122] Specific examples of the rubber material include block copolymers of aromatic vinyl compounds and conjugated diene compounds. As the block copolymer, styrene-based resins such as styrene-isoprene copolymer, styrene-isoprene-styrene copolymer, styrene-isoprenebutadiene-styrene copolymer, styrene-butadiene-styrene copolymer, styrene-ethylene-butylene copolymer, styrene-ethylene-propylene copolymer, and hydrogenated products thereof are preferred. The rubber material may be used alone or in combination of two or more. Among these, it is more preferred to use two or more styrene-based resins in combination, since it can impart excellent adhesive properties and holding power to the adhesive tape. In particular, it is preferred to use a mixture of a styrene-isoprene copolymer and a styrene-isoprene-styrene copolymer.

[0123] In the adhesive layer of this embodiment, it is preferable that 50 to 100 mass% of the entire adhesive resin (100 mass%) is accounted for by a block copolymer of an aromatic vinyl compound and a conjugated diene compound, and it is more preferable that 70 to 100 mass% is accounted for by a block copolymer of an aromatic vinyl compound and a conjugated diene compound.

[0124] The styrene resin may be, for example, a resin having a single structure such as a linear structure, a branched structure, or a multi-branched structure, or may be a mixture of resins having different structures. When the styrene resin having a large amount of linear structure is used in the adhesive layer, the adhesive tape has excellent adhesive performance. On the other hand, a resin having a branched or multi-branched structure and having a styrene block at the molecular end can form a pseudo-crosslinked structure, and therefore exhibits excellent cohesive force, and can impart high holding power to the adhesive layer. For this reason, it is preferable to mix and use the styrene resin used as the adhesive resin according to the required characteristics.

[0125] The styrene resin preferably contains the structural unit represented by the following general formula (1) in the range of 10% by mass to 80% by mass, more preferably 12% by mass to 60% by mass, even more preferably 15% by mass to 40% by mass, and particularly preferably 17% by mass to 35% by mass, based on the total mass of the styrene resin, which allows the resin to exhibit excellent adhesiveness and heat resistance. [ka]

[0126] When a styrene-isoprene copolymer and a styrene-isoprene-styrene copolymer are used in combination as the styrene-based resin used in the adhesive resin of this embodiment, the content of the styrene-isoprene copolymer relative to the total mass of the styrene-isoprene copolymer and the styrene-isoprene-styrene copolymer is preferably 0% by mass to 80% by mass, more preferably 0% by mass to 77% by mass, even more preferably 0% by mass to 75% by mass, and particularly preferably 0% by mass to 70% by mass. When the content of the styrene-isoprene copolymer is within the above-mentioned preferred range, an adhesive tape that combines excellent adhesive performance and heat durability can be provided.

[0127] The weight average molecular weight (Mw) of the styrene-isoprene copolymer is preferably in the range of 10,000 to 800,000, more preferably in the range of 30,000 to 500,000, and even more preferably in the range of 50,000 to 300,000. The weight average molecular weight is a value measured using a gel permeation chromatograph (GPC) in terms of standard polystyrene. When the weight average molecular weight of the styrene-isoprene copolymer is within the above range, it is possible to ensure heat flowability or compatibility when diluted with a solvent, which is preferable in that an adhesive tape having heat durability can be obtained while ensuring good workability in the production process.

[0128] The weight average molecular weight (Mw) of the styrene-isoprene copolymer by GPC is measured using a GPC apparatus (SC-8020, manufactured by Tosoh Corporation) and is a value converted into standard polystyrene. The measurement conditions are as follows: -Measurement conditions- Sample concentration: 0.5% by mass (THF (tetrahydrofuran) solution) Sample injection volume: 100μL Eluent: THF · Flow rate: 1.0mL / min · Measurement temperature: 40℃ - Column: TSKgel® GMHHR-H(20) x 2 Guard column: TSKgel HXL-H Detector: Differential refractometer Standard polystyrene molecular weight: 10,000 to 20 million (Tosoh Corporation)

[0129] The method for producing the styrene resin used in the pressure-sensitive adhesive resin of the present embodiment is not particularly limited and can be appropriately selected from known production methods. For example, after preparing a block copolymer by an anionic living polymerization method, a coupling agent is added as necessary and reacted to produce the target styrene resin. The method for producing a styrene-isoprene copolymer, which is a preferred example of the styrene-based resin, is not particularly limited and may be appropriately selected from known production methods, such as a method for sequentially polymerizing a styrene block and an isoprene block by an anionic living polymerization method.

[0130] Furthermore, the method for producing a styrene-isoprene-styrene copolymer, which is a preferred example of the styrene-based resin, is not particularly limited and can be appropriately selected from known production methods, such as a method of sequentially polymerizing a styrene block and an isoprene block by an anionic living polymerization method, or a method of producing a block copolymer having a living active end, and then reacting it with a coupling agent to produce a coupled block copolymer.

[0131] The method for producing the mixture of the styrene-isoprene copolymer and the styrene-isoprene-styrene copolymer is not particularly limited and can be appropriately selected from known production methods, such as a method of mixing the styrene-isoprene copolymer and the styrene-isoprene-styrene copolymer produced by the above method by a known mixing means.

[0132] Furthermore, in another method for producing the mixture of the styrene-isoprene copolymer and the styrene-isoprene-styrene copolymer, they may be produced simultaneously as a mixture in one polymerization step. A more specific example of a method for producing the mixture of the styrene-isoprene copolymer and the styrene-isoprene-styrene copolymer includes the following first to fourth steps using an anionic living polymerization method. The first step is a step of polymerizing a styrene monomer in a polymerization solvent using an anionic polymerization initiator to form a polystyrene block having a living active terminal. The second step is a step of polymerizing isoprene from the living active end of the polystyrene block to obtain a styrene-isoprene diblock copolymer having a living active end. The third step is a step of reacting a part of the styrene-isoprene diblock copolymer having a living active end with a coupling agent to form a coupled styrene-isoprene-styrene block copolymer. The fourth step is a step of deactivating the living active ends of the remaining styrene-isoprene diblock copolymer using a polymerization terminator to form a styrene-isoprene diblock copolymer.

[0133] --Tackifying resin (A2)-- The rubber-based pressure-sensitive adhesive resin in this embodiment is preferably used in combination with a tackifier resin (a2) in order to improve the adhesion to the adherend and the surface adhesive strength. The tackifier resin (a2) used in combination with the rubber-based adhesive resin is not particularly limited and can be appropriately selected depending on the purpose. For example, it is preferable to use a tackifier resin (a3) ​​having a softening point of 80° C. or higher. This makes it possible to provide an adhesive tape that has both excellent initial adhesion and heat durability.

[0134] The tackifier resin (a2) used in combination with the rubber-based adhesive resin is preferably a resin that is solid at room temperature (23°C). Specific examples of the tackifier resin include petroleum resin, polymerized rosin resin, terpene resin, rosin resin, terpene-phenol resin, styrene resin, coumarone-indene resin, xylene resin, and phenol resin. Examples of the petroleum resin include C5-based petroleum resin, C9-based petroleum resin, C5 / C9-based petroleum resin, and alicyclic petroleum resin. These resins may be used alone or in combination of two or more. Among these, the tackifier resin used in combination with the rubber-based adhesive resin is preferably a combination of C5-based petroleum resin and polymerized rosin resin, from the viewpoint of achieving both even better initial adhesion and heat durability.

[0135] The petroleum resin is easily compatible with the styrene monomer unit represented by the general formula (1) constituting the styrene-based resin, and therefore can further improve the initial adhesive strength and heat durability of the adhesive tape.

[0136] Examples of the C5 petroleum resin include the Escorez series (Escorez 1202, Escorez 1304, or Escorez 1401) manufactured by ExxonMobil Corporation, Wingtac 95 manufactured by The Goodyear Tire & Rubber Company, the Quinton series (Quinton K100, Quinton R100, or Quinton F100) manufactured by Zeon Corporation, or Picotac 95 or Picopal 100 manufactured by Rika Hercules Corporation.

[0137] Examples of the C9 petroleum resin include the Nippon Oil Neopolymer series manufactured by JX Nippon Oil & Energy Corporation (Nippon Oil Neopolymer-L-90, Nippon Oil Neopolymer-120, Nippon Oil Neopolymer-130, Nippon Oil Neopolymer-140, Nippon Oil Neopolymer-150, Nippon Oil Neopolymer-170S, Nippon Oil Neopolymer-160, Nippon Oil Neopolymer-E-100, Nippon Oil Neopolymer-E-130, Nippon Oil Neopolymer-130S, or Nippon Oil Neopolymer-S), and Petokol (registered trademark) manufactured by Tosoh Corporation.

[0138] The C5 / C9 petroleum resin may be a copolymer of a C5 petroleum resin and a C9 petroleum resin. Specific examples of the C5 / C9 petroleum resin include Escoretz 2101 manufactured by Exxon Mobil Corporation, Quinton G115 manufactured by Zeon Corporation, and Harcotack 1149 manufactured by Rika Hercules Corporation.

[0139] The alicyclic petroleum resin can be obtained by hydrogenating a C9 petroleum resin, and examples thereof include Escoretz 5300 manufactured by Exxon Mobil Corporation, Alcorn P-100 manufactured by Arakawa Chemical Industries Co., Ltd., and Regalite R101 manufactured by Rika Hercules Co., Ltd.

[0140] The amount of the tackifier resin (a2) used is not particularly limited and can be appropriately selected depending on the purpose. The tackifier resin is preferably used in the range of 0% to 100% by mass, more preferably in the range of 0% to 70% by mass, even more preferably in the range of 0% to 50% by mass, and particularly preferably in the range of 0% to 30% by mass, relative to the total amount (100% by mass) of the components constituting the rubber-based adhesive resin. When the tackifier resin is used within the preferred range, the adhesion at the interface between the adhesive layer and the base layer is improved, and the adhesive tape is easily able to have both excellent breaking elongation and heat durability.

[0141] The amount of the tackifier resin (a3) ​​having a softening point of 80° C. or higher used is not particularly limited and can be appropriately selected depending on the purpose. For example, the tackifier resin having a softening point of 80° C. or higher is preferably used in the range of 3% by mass to 100% by mass, more preferably in the range of 5% by mass to 80% by mass, relative to the total amount of the styrene-based resin. When emphasis is placed on the viewpoint of providing an adhesive tape that combines even more excellent adhesiveness and excellent heat durability, it is particularly preferable to use it in the range of 5% by mass to 80% by mass.

[0142] In addition, for the purpose of obtaining application property or initial adhesion in a constant temperature environment, a tackifier resin (a3) ​​having a softening point of 80°C or higher may be used in combination with a tackifier resin (a4) having a softening point of -5°C or lower.

[0143] The tackifier resin (a4) having a softening point of -5°C or less is not particularly limited and can be appropriately selected from known tackifier resins depending on the purpose. For example, it is preferable to use a tackifier resin (a4) that is liquid at room temperature (20°C to 27°C).

[0144] Specific examples of the tackifier resin (a4) having a softening point of -5°C or less include process oil, and liquid rubber such as polyester or polybutene. These liquid rubbers may be used alone or in combination of two or more. From the viewpoint of exerting even more excellent initial adhesion, it is preferable to use polybutene as the tackifier resin (a4) having a softening point of -5°C or less.

[0145] The tackifier resin (a4) having a softening point of -5°C or lower preferably occupies a range of 0 to 40 mass%, and more preferably 0 to 30 mass%, relative to the total amount (100 mass%) of the tackifier resin (a2).

[0146] The tackifier resin (a4) having a softening point of -5°C or less is preferably used in a range of 0 mass% to 40 mass% relative to the total amount (100 mass%) of the styrene-based resin used in the adhesive resin, and more preferably in a range of 0 mass% to 30 mass% when emphasis is placed on improving the initial adhesive strength, having good adhesiveness, and exhibiting sufficient heat durability.

[0147] The mass ratio of the tackifier resin (a3) ​​having a softening point of 80° C. or more to the tackifier resin (a4) having a softening point of −5° C. or less is not particularly limited and can be appropriately selected depending on the purpose. The mass ratio of the tackifier resin (a3) ​​having a softening point of 80° C. or more to the tackifier resin (a4) having a softening point of −5° C. or less, expressed as [mass of the tackifier resin (a3) ​​having a softening point of 80° C. or more / mass of the tackifier resin (a4) having a softening point of −5° C. or less], is preferably used in the range of 5 to 50, and when emphasis is placed on the viewpoint of obtaining an adhesive tape that combines excellent initial adhesion and excellent holding power, it is more preferable to use in the range of 10 to 30.

[0148] The mass ratio of the styrene resin used in the adhesive resin to the tackifier resin used in combination with the rubber-based adhesive resin is not particularly limited and can be appropriately selected according to the purpose. For example, the mass ratio of the styrene resin to the tackifier resin, expressed as [styrene resin / tackifier resin used in combination with the rubber-based adhesive resin], is preferably used in the range of 0.5 to 10.0, and when the viewpoint of improving the initial adhesive strength and obtaining excellent heat durability is emphasized, it is more preferable to use in the range of 0.6 to 9.0. In addition, the mass ratio [styrene resin / tackifier resin used in combination with the rubber-based adhesive resin] is preferably larger than 1 in order to prevent peeling caused by the repulsive force of the adhesive tape when it is attached to a curved surface of an adherend (repulsion resistance), for example.

[0149] <Adhesive layer optional components> In this embodiment, when the above-mentioned acrylic adhesive resin or rubber adhesive resin is used as the adhesive resin, the optional adhesive layer components added to the adhesive layer are not particularly limited and can be appropriately selected within a range that does not impair the properties of the adhesive tape. For example, polymer components other than the adhesive resin, crosslinking agents, antiaging agents, UV absorbers, fillers, polymerization inhibitors, surface conditioners, antistatic agents, defoamers, viscosity modifiers, light resistance stabilizers, weather resistance stabilizers, heat resistance stabilizers, antioxidants, leveling agents, additives such as organic pigments, inorganic pigments, pigment dispersants, plasticizers, softeners, flame retardants, metal deactivators, silica beads, organic beads, etc.; inorganic fillers such as silicon oxide, aluminum oxide, titanium oxide, zirconia, and antimony pentoxide, etc. may be mentioned. These optional adhesive layer components may be used alone or in combination of two or more. The content of the optional components in the adhesive layer can be appropriately selected within a range that does not impair the properties of the adhesive tape.

[0150] <<Other adhesive resins>> In the present embodiment, as the other adhesive resin, one or more types selected from the group consisting of known urethane-based adhesive resins, silicone-based adhesive resins, and mixed adhesives may be used.

[0151] <Characteristics of the adhesive layer> In this embodiment, the stress of the adhesive layer at 25% elongation is not particularly limited and can be appropriately selected depending on the purpose, but is preferably 0.04 MPa to 0.4 MPa, more preferably 0.05 MPa to 0.1 MPa. When the stress of the adhesive layer at 25% elongation is within the preferred range, the adhesive tape can have a suitable adhesive strength, and can be relatively easily peeled off even when stretched and peeled. On the other hand, when the stress of the adhesive layer at 25% elongation is less than 0.04 MPa, the adhesive tape may peel off when a load is applied in the shear direction of the adhesive tape while fixing hard adherends to each other, and when it exceeds 0.4 MPa, the force required to stretch the adhesive tape when peeling the adhesive tape may be excessive. The stress of the adhesive layer at 25% elongation refers to the stress value measured when the adhesive layer is punched out into a dumbbell shape with a gauge length of 20 mm and a width of 10 mm, and pulled in the length direction at a tensile speed of 300 mm / min using a Tensilon tensile testing machine (model: RTF-1210, manufactured by A&D Co., Ltd.) under measurement conditions of 23°C and 50% RH, and elongated by 25%.

[0152] In this embodiment, the breaking strength of the adhesive layer is not particularly limited and can be appropriately selected according to the purpose, but is preferably 0.5 MPa to 2.1 MPa, more preferably 1.0 MPa to 2.1 MPa. When the breaking strength of the adhesive layer is within the above-mentioned preferred range, the adhesive tape can be prevented from tearing even when the adhesive tape is stretched and peeled off, and the load for stretching the adhesive tape is not excessive, so that the peeling operation is easy. On the other hand, when the breaking strength of the adhesive layer is less than 0.5 MPa, adhesive residue may occur due to cohesive failure of the adhesive layer when the adhesive tape is stretched and peeled off, and when it exceeds 2.1 MPa, sufficient adhesiveness may not be obtained. The force required to stretch and deform the adhesive tape also depends on the thickness of the adhesive tape. For example, even when an adhesive tape with a large thickness and high breaking strength is stretched and peeled off, it may not be stretched sufficiently and cannot be peeled off. The breaking strength of the adhesive layer refers to the stress value measured when the adhesive layer is punched out into a dumbbell shape with a gauge length of 20 mm and a width of 10 mm, and pulled in the lengthwise direction at a tensile speed of 300 mm / min using a Tensilon tensile tester (model: RTF-1210, manufactured by A&D Co., Ltd.) under conditions of a measurement atmosphere of 23°C and 50% RH, until the adhesive layer breaks.

[0153] In the present embodiment, the breaking elongation of the adhesive layer is not particularly limited and can be appropriately selected depending on the purpose, but is preferably 450% to 1300%, more preferably 500% to 1200%, and even more preferably 600% to 1100%. When the breaking elongation of the adhesive layer is within the above-mentioned preferred range, it is possible to achieve both suitable adhesion and removability (ease of peeling). The breaking elongation of the adhesive layer refers to the tensile elongation percentage measured when the adhesive layer is punched out into a dumbbell shape with a gauge length of 20 mm and a width of 10 mm, and pulled in the length direction at a tensile speed of 300 mm / min using a Tensilon tensile tester (model: RTF-1210, manufactured by A&D Co., Ltd.) under conditions of a measurement atmosphere of 23°C and 50% RH, until breaking.

[0154] In the present embodiment, the average thickness of the adhesive layer is not particularly limited and can be appropriately selected depending on the purpose, but is preferably 5 μm to 150 μm, more preferably 20 μm to 120 μm, even more preferably 40 μm to 110 μm, and particularly preferably 50 μm to 100 μm. The "thickness of the adhesive layer" means the thickness of a single adhesive layer in the adhesive tape. For example, when the adhesive tape has a base layer and adhesive layers on both sides of the base layer, the average thickness of the adhesive layer on one side and the average thickness of the adhesive layer on the other side may be the same or different, but are preferably the same thickness. In this specification, the thickness of the adhesive layer can be measured by the following method. That is, after immersing the adhesive tape in liquid nitrogen for 1 minute, the adhesive tape is folded and split in the liquid nitrogen using tweezers along the width direction to prepare a slice for observing the cut surface in the thickness direction of the adhesive tape. After the slice is returned to room temperature in a desiccator, it is fixed to a sample stage so that an electron beam is incident perpendicularly to the cut surface, and the cut surface is observed using an electron microscope. Based on the scale of the electron microscope, the thickness of the adhesive layer in the adhesive tape is measured at 10 points, and the arithmetic average value is taken as the thickness of the adhesive layer. The thickness of the adhesive layer is the length measured along the lamination direction from one surface to the other surface.

[0155] [Base material layer] The adhesive tape of this embodiment essentially comprises an adhesive layer, and may have a base layer as necessary. One example of the adhesive tape of this embodiment comprises an adhesive layer and a base layer provided on one side of the adhesive layer. Another example of the adhesive tape of this embodiment comprises a pair of adhesive layers and a base layer disposed between the pair of adhesive layers, and the thickness of the base layer is preferably 20 to 200 μm. The breaking strength of the base layer is preferably 1 to 90 MPa. The breaking elongation of the base layer is preferably 400 to 1500%. The base layer of the present embodiment is preferably formed from a base layer composition described below. The base layer composition may contain optional base layer components or a solvent (such as a known organic solvent) in addition to the base material, as necessary.

[0156] In the adhesive tape according to the present embodiment, when a substrate layer is provided, the substrate layer may be an extensible substrate having extensibility or a non-extensible substrate having no extensibility, but when emphasis is placed on the viewpoint of stretch peeling, it is preferable to use an extensible substrate. In this specification, "having extensibility" means showing a breaking elongation of 400% or more, while "not having extensibility" means showing a breaking elongation of less than 400%. Therefore, a non-extensible substrate means a substrate having a breaking elongation of less than 400%, and an extensible substrate means a substrate having a breaking elongation of 400% or more. In the case where the adhesive tape according to the present embodiment has a base layer, if particulate matter (such as silicone composite filler or microballoons) is present in the adhesive layer, the adhesive strength (anchoring strength) between the base layer and the adhesive layer tends to decrease. Therefore, in the peeling or removal operation from the adherend, such as stretch peeling, the phenomenon of peeling at the interface between the adhesive layer and the base layer may occur. For example, in the case of an adhesive tape having an adhesive layer and a base layer containing microballoons and an adhesive resin, it was confirmed that the adhesive strength between the adhesive layer and the base layer is reduced, and therefore the interface is easily peeled off during stretch peeling. In addition, in the case of an adhesive tape having an adhesive layer and a base layer formed from a composition for an adhesive layer containing an acrylic modified silicone and an adhesive resin, it was confirmed that the impact resistance and holding power are not improved. However, in this embodiment, it was confirmed that the use of different particles of silicone composite filler and microballoons reduces the interfacial peeling between the adhesive layer and the base layer, and in particular, it was confirmed that the use of an adhesive layer having silicone composite filler, microballoons, and acrylic-modified silicone tends to effectively suppress interfacial peeling. Although the reason for this is not clear, it is presumed that the acrylic-modified portion of the acrylic-modified silicone has affinity with the adhesive resin in the adhesive layer, and the particles become swollen by incorporating the adhesive component in the adhesive layer, so that the elasticity of the adhesive layer is easily maintained. From the above, when the adhesive tape of the present embodiment comprises an adhesive layer and a base layer provided on one side of the adhesive layer, the adhesive layer or a composition for the adhesive layer forming the adhesive layer preferably contains a silicone composite filler, microballoons and an acrylic modified silicone, which improves impact resistance, cuttability and dismantling property during stretch peeling (= ease of peeling or removal work).

[0157] In this embodiment, the base layer is not particularly limited as long as it has the above-mentioned characteristics, and can be appropriately selected from known materials that can be used for adhesive tapes. It is preferable that the base layer contains the following base material materials, and may further contain other components as necessary. In addition, as an example of the base layer of this embodiment, it is preferable that the base layer is an elastic base layer. The base layer may have a single layer structure, or a multi-layer structure of two layers, three layers, or more.

[0158] In this embodiment, the breaking strength of the base layer is 1 to 90 MPa, preferably 5 to 90 MPa, more preferably 10 to 88 MPa, and even more preferably 15 to 85 MPa. When the breaking strength is 1 MPa or more, the adhesive tape can be peeled off from the adherend without tearing even if the worker pulls it when peeling it off from the adherend. When the breaking strength is 90 MPa or less, the worker can avoid excessive stress when pulling the adhesive tape. The breaking strength of the above-mentioned base material layer refers to the stress value measured when the base material layer is punched out into a dumbbell shape with a gauge length of 20 mm and a width of 5 mm, and pulled in the longitudinal direction at a tensile speed of 500 mm / min using a Tensilon tensile tester (model: RTF-1210, manufactured by A & D Co., Ltd.) under conditions of a measurement atmosphere of 23°C and 50% RH, and broken. The breaking strength can be adjusted by appropriately selecting the material and by applying stretching during the manufacturing process of the base layer.

[0159] In this embodiment, the breaking elongation of the base layer is 400 to 1500%, preferably 500 to 1300%, and more preferably 600 to 1200%. When the breaking elongation is 400% or more, even if the adhesive tape is firmly attached to the adherend, the stress when peeling off the adhesive tape is not too large. Also, when the breaking elongation is 1500% or less, the stretching distance when peeling off the adhesive tape is not too long, making it possible to work in a small space. Therefore, when the breaking elongation of the base layer satisfies the physical property in the above range, the slipperiness during stretch peeling is improved. The breaking elongation of the base material layer refers to the tensile elongation percentage measured when the base material layer is punched out into a dumbbell shape with a gauge length of 20 mm and a width of 5 mm, and pulled in the length direction at a tensile speed of 500 mm / min using a Tensilon tensile tester (model: RTF-1210, manufactured by A&D Co., Ltd.) under conditions of a measurement atmosphere of 23°C and 50% RH, and broken. The breaking elongation can be adjusted by appropriately selecting the material and by applying stretching during the manufacturing process of the base layer.

[0160] In the base layer of this embodiment, the 100% modulus is preferably 0.1 to 5 MPa, more preferably 0.5 to 4.5 MPa, and even more preferably 1 to 4 MPa. When the 100% modulus is 0.1 MPa or more, defects associated with deformation such as slippage when a load is applied to the adhesive tape or adherend can be suppressed. Furthermore, when the 100% modulus is 5 MPa or less, an operator can pull the adhesive tape from the adherend with a relatively light force in the initial stage of peeling it off. The 100% modulus of the base material layer refers to the stress value measured when the base material layer is punched out into a dumbbell shape with a gauge length of 20 mm and a width of 5 mm, and pulled in the longitudinal direction at a tensile speed of 500 mm / min using a Tensilon tensile testing machine (model: RTF-1210, manufactured by A&D Co., Ltd.) under measurement atmosphere conditions of 23°C and 50% RH, and the elongation is 100%. The 100% modulus can be adjusted by appropriately selecting the material and by applying stretching during the manufacturing process of the base layer.

[0161] In this embodiment, the rubber hardness of the base layer is preferably 20 to 90 A, more preferably 30 to 85 A, and further preferably 40 to 80 A. By having a rubber hardness of 20 A or more, it is possible to prevent the adhesive tape from tearing when stretching and peeling it off. In addition, by having a rubber hardness of 90 A or less, the base layer becomes soft, and for example, when an adherend to which the adhesive tape is attached is dropped, the adhesive tape becomes more likely to absorb the impact, and the adherend can be protected from the impact (the impact resistance of the adhesive tape can be improved). The rubber hardness of the base layer is Shore A hardness, and refers to a value measured in accordance with JIS K 6253 using a durometer (spring type rubber hardness tester) (model: GS-719G, manufactured by Techclock Corporation). In addition, the rubber hardness can be adjusted by appropriately selecting the material, for example, by changing the molecular weight of the resin, or by changing the monomer unit if a styrene monomer unit is contained.

[0162] In this embodiment, the thickness of the base layer is 20 to 500 μm, preferably 15 to 500 μm, and more preferably 20 to 400 μm. A thickness of 20 μm or more ensures the strength of the adhesive tape, and a thickness of 500 μm or less prevents the adhesive tape from becoming too thick and making it difficult to pull. In this specification, the "thickness of the base layer" refers to the average value of the thicknesses measured at any five points in the base layer using a TH-104 paper / film thickness meter (manufactured by Tester Sangyo Co., Ltd.).

[0163] The thickness ratio of the adhesive layer to the base layer is not particularly limited and can be appropriately selected according to the purpose, but the ratio of the thickness of the adhesive layer to the thickness of the base layer, expressed as [thickness of the adhesive layer / thickness of the base layer], is preferably 1 / 5 to 5 / 1, more preferably 1 / 3 to 3 / 1, and even more preferably 1 / 2 to 2 / 1. When the thickness ratio of the adhesive layer to the thickness of the base layer is within a preferred range, the adhesive tape can have excellent adhesion and removability (ease of peeling). On the other hand, when the ratio is greater than 5 / 1, there is a possibility that only the adhesive layer will remain on the adherend in the re-peeling process of the adhesive tape. In addition, when the ratio is less than 1 / 5, there is a concern that the adhesive layer will not be able to follow the surface of the adherend when it has an uneven shape, and the adhesive strength will decrease. The substrate layer of the present embodiment is preferably formed from a substrate layer composition containing a substrate material and, if necessary, optional substrate layer components and / or a solvent (such as an organic solvent) added thereto so as to have the desired breaking strength, breaking elongation, rubber hardness and thickness depending on the purpose.

[0164] <Material for base material> The substrate material used for the substrate layer of the present embodiment is not particularly limited as long as it can obtain a substrate layer having the above-mentioned specific physical properties, but examples thereof include styrene-isoprene copolymer, styrene-isoprene-styrene copolymer, styrene-isoprenebutadiene-styrene copolymer, styrene-butadiene-styrene copolymer, styrene-ethylene-butylene copolymer, styrene-ethylene-propylene copolymer, and other styrene-based resins; polyurethane resins such as ester-based polyurethane and ether-based polyurethane; polyolefin resins such as polyethylene and polypropylene; polyester resins such as polyethylene terephthalate, polybutylene terephthalate, and polyethylene naphthalate; polystyrene; polycarbonate; polymethylpentene; polysulfone; polyetheretherketone; polyethersulfone; polyetherimide; polyimide film; fluorine resin; nylon; acrylic resin, etc. These may be used alone or in combination of two or more types, but it is preferable to use two or more types in combination. Among these, styrene-based resins and polyurethane resins are preferred because suitable breaking strength and breaking elongation can be easily obtained, styrene-based resins are more preferred, and it is particularly preferred to use a combination of a styrene-isoprene copolymer and a styrene-isoprene-styrene copolymer.

[0165] --Styrene-based resin-- Since the styrene resin is a resin exhibiting thermoplasticity, it has excellent moldability in extrusion molding, injection molding, etc., and is easy to mold into a substrate layer. Moreover, the styrene resin is particularly likely to have excellent breaking elongation among the group of resins generally called thermoplastic resins, and can be suitably used as a substrate for an adhesive sheet.

[0166] Therefore, in the substrate material, the proportion of the styrene resin relative to the total resin components is preferably 50% to 100%, more preferably 60% to 100%, even more preferably 65% ​​to 100%, and particularly preferably 70% to 100%. By keeping the proportion of the styrene resin within the above-mentioned preferred range, a substrate layer having excellent breaking elongation and breaking strength can be obtained.

[0167] The styrene resin used as the substrate material may be a resin having a single structure such as a linear structure, a branched structure, or a multi-branched structure, as in the case of the adhesive resin, or may be a mixture of resins having different structures. A styrene resin rich in linear structures can provide the substrate layer with excellent breaking elongation. On the other hand, a branched or multi-branched structure having a styrene block at the molecular end can have a pseudo-crosslinked structure and provide excellent cohesive strength. For this reason, it is preferable to use a mixture of styrene resins according to the required mechanical properties.

[0168] The styrene resin preferably contains the structural unit represented by the above chemical formula (1) in the range of 13% by mass to 60% by mass, more preferably 15% by mass to 50% by mass, even more preferably 15% by mass to 45% by mass, and particularly preferably 15% by mass to 35% by mass, relative to the total mass of the styrene resin. When the ratio of the structural unit represented by the following chemical formula (1) to the total mass of the styrene resin is within the above-mentioned preferred range, it becomes easier to obtain the breaking elongation and breaking strength in the suitable range.

[0169] When a styrene-isoprene copolymer and a styrene-isoprene-styrene copolymer are used in combination as the styrene-based resin, the content of the styrene-isoprene copolymer relative to the total mass of the styrene-isoprene copolymer and the styrene-isoprene-styrene copolymer is preferably 0% by mass to 80% by mass, more preferably 0% by mass to 70% by mass, even more preferably 0% by mass to 50% by mass, and particularly preferably 0% by mass to 30% by mass. When the content of the styrene-isoprene copolymer is within the above-mentioned preferred range, it is possible to achieve both excellent thermal durability while maintaining excellent breaking elongation and breaking strength.

[0170] The styrene-isoprene copolymer preferably has a weight average molecular weight measured in terms of standard polystyrene using gel permeation chromatography (GPC) in the range of 10,000 to 800,000, more preferably in the range of 30,000 to 500,000, and even more preferably in the range of 50,000 to 300,000. When the weight average molecular weight of the styrene-isoprene copolymer is within the above-mentioned preferred range, it is possible to ensure heat flowability and compatibility when diluted with a solvent, and therefore it is preferable that a base layer having good workability in the production process and heat durability can be obtained.

[0171] Here, the weight average molecular weight of the styrene-isoprene copolymer is measured by the GPC method using a GPC apparatus (SC-8020, manufactured by Toso Corporation) and is a value converted into standard polystyrene. The measurement conditions are as follows: -Measurement conditions- Sample concentration: 0.5% by mass (tetrahydrofuran solution) Sample injection volume: 100μL Eluent: Tetrahydrofuran · Flow rate: 1.0mL / min · Measurement temperature: 40℃ - Column: TSKgel® GMHHR-H(20) x 2 Guard column: TSKgel HXL-H Detector: Differential refractometer Standard polystyrene molecular weight: 10,000 to 20 million (Tosoh Corporation)

[0172] The method for producing the styrene-isoprene copolymer, the styrene-isoprene-styrene copolymer, and the mixture of the styrene-isoprene copolymer and the styrene-isoprene-styrene copolymer is not particularly limited and can be appropriately selected from conventionally known production methods. The block copolymer can be obtained by an anionic living polymerization method, and a coupling agent can be added and reacted as necessary. Specifically, the method for producing a styrene-isoprene copolymer is not particularly limited and can be appropriately selected from conventionally known production methods, such as a method in which a styrene block and an isoprene block are sequentially polymerized by an anionic living polymerization method.

[0173] The method for producing a styrene-isoprene-styrene copolymer is not particularly limited and can be appropriately selected from conventionally known production methods. Examples of the method include a method in which a styrene block and an isoprene block are sequentially polymerized by an anionic living polymerization method, and a method in which a block copolymer having a living active end is produced and then reacted with a coupling agent to produce a coupled block copolymer.

[0174] The method for producing the mixture of styrene-isoprene copolymer and styrene-isoprene-styrene copolymer is not particularly limited and can be appropriately selected from conventionally known production methods. For example, a method of mixing the styrene-isoprene copolymer produced by the above method with a styrene-isoprene-styrene copolymer can be mentioned.

[0175] As a method for producing a mixture of a styrene-isoprene copolymer and a styrene-isoprene-styrene copolymer, it is also possible to produce them as a mixture simultaneously in one polymerization step. In a more specific embodiment, the anionic living polymerization method involves first polymerizing a styrene monomer in a polymerization solvent using an anionic polymerization initiator to form a polystyrene block having a living active end. Secondly, isoprene is polymerized from the living active end of the polystyrene block to obtain a styrene-isoprene diblock copolymer having a living active end. Thirdly, a part of the styrene-isoprene diblock copolymer having a living active end is reacted with a coupling agent to form a coupled styrene-isoprene-styrene block copolymer. Fourthly, the remaining part of the styrene-isoprene diblock copolymer having a living active end is deactivated at its living active end using a polymerization terminator to form a styrene-isoprene diblock copolymer.

[0176] --Polyurethane resin-- The polyurethane resin is not particularly limited and can be appropriately selected depending on the purpose, but preferably has a softening point of 40° C. or more, and more preferably has a softening point of 50° C. or more. The upper limit of the softening point is preferably 100° C. or less. The softening point refers to a value measured in accordance with JIS K 2207 (ring and ball method) (the same applies to the softening point below).

[0177] As the polyurethane resin, a reaction product of a polyol (b1-1) and a polyisocyanate (b1-2) can be suitably used.

[0178] The polyol (b1-1) is not particularly limited and can be appropriately selected according to the purpose, and examples thereof include polyester polyol, polyether polyol, polycarbonate polyol, and acrylic polyol. These may be used alone or in combination of two or more. Among these, polyester polyol and polyether polyol are preferred as the polyol (b1-1) because they can provide the mechanical properties of the base layer. When heat resistance is required in the base layer, it is preferred to use polyester polyol, and when water resistance or biodegradability is required, it is preferred to use polyether polyol.

[0179] Examples of polyester polyols include polyesters obtained by an esterification reaction between a low molecular weight polyol and a polycarboxylic acid, polyesters obtained by a ring-opening polymerization reaction of a cyclic ester compound such as ε-caprolactone, and copolymer polyesters thereof.

[0180] Examples of low molecular weight polyols that can be used in the production of polyester polyols include aliphatic alkylene glycols such as ethylene glycol, propylene glycol, 1,4-butanediol, 1,6-hexanediol, diethylene glycol, neopentyl glycol, and 1,3-butanediol, each of which has a weight average molecular weight of about 50 to 300, and cyclohexane dimethanol.

[0181] Examples of polycarboxylic acids include aliphatic dicarboxylic acids such as succinic acid, adipic acid, sebacic acid, and dodecanedicarboxylic acid; aromatic dicarboxylic acids such as terephthalic acid, isophthalic acid, phthalic acid, and naphthalenedicarboxylic acid; and anhydrides or esters thereof.

[0182] Examples of polyether polyols include those obtained by addition polymerization of alkylene oxide using one or more compounds having two or more active hydrogen atoms as an initiator.

[0183] As the polycarbonate polyol, for example, one obtained by reacting a carbonate ester and / or phosgene with a low molecular weight polyol described later can be used.

[0184] Examples of carbonate esters include methyl carbonate, dimethyl carbonate, ethyl carbonate, diethyl carbonate, cyclocarbonate, and diphenyl carbonate.

[0185] Examples of low molecular weight polyols that can be used to produce polycarbonate polyols and that can react with carbonate esters and / or phosgene include ethylene glycol, diethylene glycol, triethylene glycol, tetraethylene glycol, 1,2-propanediol, 1,3-propanediol, dipropylene glycol, tripropylene glycol, 1,2-butanediol, 1,3-butanediol, 1,4-butanediol, 2,3-butanediol, 1,5-pentanediol, 1,5-hexanediol, 1,6-hexanediol, 2,5-hexanediol, 1 ,7-heptanediol, 1,8-octanediol, 1,9-nonanediol, 1,10-decanediol, 1,11-undecanediol, 1,12-dodecanediol, 2-methyl-1,3-propanediol, neopentyl glycol, 2-butyl-2-ethyl-1,3-propanediol, 3-methyl-1,5-pentanediol, 2-ethyl-1,3-hexanediol, 2-methyl-1,8-octanediol, 1,4-cyclohexanedimethanol, hydroquinone, resorcinol, bisphenol A, bisphenol F, 4,4'-biphenol, and the like.

[0186] The polyisocyanate (b1-2) is not particularly limited and can be appropriately selected depending on the purpose, and examples of the polyisocyanate that can be used include alicyclic polyisocyanates, aliphatic polyisocyanates, aromatic polyisocyanates, etc., and examples of the polyisocyanate include alicyclic polyisocyanates, etc. These may be used alone or in combination of two or more kinds.

[0187] Examples of alicyclic polyisocyanates include isophorone diisocyanate, 1,3-bis(isocyanatomethyl)cyclohexane, 4,4'-dicyclohexylmethane diisocyanate, 2,4-methylcyclohexane diisocyanate, 2,6-methylcyclohexane diisocyanate, cyclohexylene diisocyanate, methylcyclohexylene diisocyanate, bis(2-isocyanatoethyl)-4-cyclohexylene-1,2-dicarboxylate, 2,5-norbornane diisocyanate, 2,6-norbornane diisocyanate, dimer acid diisocyanate, bicycloheptane triisocyanate, etc. These may be used alone or in combination of two or more.

[0188] The method for producing the polyurethane resin (b1) by reacting the polyol (b1-1) with the polyisocyanate (b1-2) is not particularly limited and may be appropriately selected from conventionally known production methods. For example, there may be mentioned a method in which the polyol (b1-1) charged in a reaction vessel is heated under normal pressure or reduced pressure conditions to remove moisture, and then the polyisocyanate (b1-2) is supplied all at once or in portions and reacted.

[0189] The reaction between the polyol (b1-1) and the polyisocyanate (b1-2) is preferably carried out in such a manner that the equivalent ratio (NCO / OH equivalent ratio) of the isocyanate group (NCO) in the polyisocyanate (b1-2) to the hydroxyl group (OH) in the polyol (b1-1) is in the range of 1.0 to 20.0, more preferably in the range of 1.1 to 13.0, even more preferably in the range of 1.2 to 5.0, and particularly preferably in the range of 1.5 to 3.0.

[0190] The reaction conditions for the polyol (b1-1) and the polyisocyanate (b1-2) are not particularly limited and can be appropriately selected taking into consideration various conditions such as safety, quality, and cost. The reaction temperature is preferably 70°C to 120°C, and the reaction time is preferably 30 minutes to 5 hours.

[0191] When reacting the polyol (b1-1) with the polyisocyanate (b1-2), a catalyst such as a tertiary amine catalyst or an organometallic catalyst may be used as necessary.

[0192] The reaction may be carried out in a solvent-free environment or in the presence of an organic solvent. The organic solvent is not particularly limited and can be appropriately selected according to the purpose, and examples thereof include ester-based solvents such as methyl acetate, ethyl acetate, propyl acetate, and butyl acetate; ketone-based solvents such as acetone, methyl ethyl ketone, methyl butyl ketone, and cyclohexanone; ether ester-based solvents such as methyl cellosolve acetate and butyl cellosolve acetate; aromatic hydrocarbon-based solvents such as toluene and xylene; and amide-based solvents such as dimethylformamide and dimethylacetamide. These may be used alone or in combination of two or more. The organic solvent may be removed during the production of the polyurethane resin (b1) or after the production of the polyurethane (b1) by a suitable method such as heating under reduced pressure or drying at normal pressure.

[0193] --Optional components for base material layer-- The optional components of the substrate layer in the substrate layer are not particularly limited and can be appropriately selected within a range that does not impair the properties of the adhesive tape, and examples thereof include tackifier resin (b1); polymer components other than the substrate material; crosslinking agents, antiaging agents, UV absorbers, fillers, polymerization inhibitors, surface conditioners, antistatic agents, defoamers, viscosity modifiers, light stabilizers, weather stabilizers, heat stabilizers, antioxidants, leveling agents, additives such as organic pigments, inorganic pigments, pigment dispersants, silica beads, and organic beads; inorganic fillers such as silicon oxide, aluminum oxide, titanium oxide, zirconia, and antimony pentoxide. These may be used alone or in combination of two or more. The content of the optional components in the base layer can be appropriately selected within a range that does not impair the properties of the adhesive tape.

[0194] The tackifier resin (b1) can be used for the purpose of increasing the adhesion between the adhesive layer of the adhesive tape and the base layer and for the purpose of increasing the heat resistance. There is no particular limitation on the tackifier resin, and it can be appropriately selected according to the purpose, but it is preferable that the softening point is 80°C or higher, more preferably 90°C or higher, even more preferably 100°C or higher, and particularly preferably 110°C or higher. In addition, as the tackifier resin (b1) that can be used in the base layer, for example, those described in the above section "-Rubber-based adhesive resin-" can be used, and the preferred aspects are the same.

[0195] The antiaging agent is not particularly limited and can be appropriately selected from known ones according to the purpose. For example, phenol-based antiaging agents, phosphorus-based antiaging agents (sometimes called "processing stabilizers"), amine-based antiaging agents, imidazole-based antiaging agents, etc. can be mentioned. These may be used alone or in combination of two or more. Among these, phenol-based antiaging agents and phosphorus-based antiaging agents are preferred, and using them in combination is preferred because it can effectively improve the heat resistance stability of the substrate material, and as a result, it is possible to obtain an adhesive tape that maintains good initial adhesion and has even better heat durability. In addition, since phosphorus-based antiaging agents may slightly discolor (yellowing) over time in a high-temperature environment, it is preferable to appropriately set the amount used in consideration of the balance between initial adhesion, heat durability, and discoloration prevention.

[0196] As the phenolic antioxidant, generally, a phenolic compound having a steric hindrance group can be used, and monophenolic type, bisphenolic type, and polyphenolic type are representative.Specific examples include 2,6-di-t-butyl-4-methylphenol, 2,2'-methylenebis(4-methyl-6-t-butylphenol), 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]methane, and n-octadecyl-3-(4'-hydroxy-3'5'-di-t-butylphenyl)propionate. These may be used alone or in combination of two or more.

[0197] The amount of the phenolic antioxidant used is not particularly limited and can be selected appropriately depending on the purpose, but it is preferable to use it in the range of 0.1 parts by mass to 5 parts by mass per 100 parts by mass of the substrate material, and using it in the range of 0.5 parts by mass to 3 parts by mass can effectively improve the heat resistance stability of the substrate material, resulting in an adhesive tape that maintains good initial adhesion and has even better heat durability.

[0198] <Other layers> There are no particular limitations on the adhesive tape of this embodiment, and other layers can be provided as appropriate depending on the purpose, such as a primer layer, an antistatic layer, a non-flammable layer, a decorative layer, a conductive layer, a heat conductive layer, and a release layer.

[0199] <Adhesive tape shape, characteristics, etc.> The shape and dimensions of the adhesive tape of this embodiment are not particularly limited as long as it comprises an adhesive. In addition, as a preferred embodiment of the adhesive tape, the shape and dimensions are not particularly limited as long as it comprises a base layer and an adhesive layer disposed on one or both sides of the base layer. The adhesive tape of this embodiment includes, for example, an adhesive tape having a shape and dimensions suitable for attachment to a specific adherend (e.g., an adhesive tape in a state after punching processing) and a long sheet-like adhesive tape (e.g., an adhesive tape before being processed into a specific shape). Furthermore, the adhesive tape of this embodiment may be optionally provided with a non-adhesive gripping region, for example, for attaching to an adherend or peeling from an adherend.

[0200] The thickness of the adhesive tape of this embodiment is not particularly limited and can be appropriately selected depending on the thickness of the adhesive layer and the base layer that is provided if necessary, but is preferably 15 μm to 1000 μm, more preferably 30 μm to 540 μm, even more preferably 60 μm to 320 μm, and particularly preferably 70 μm to 300 μm. In this specification, "thickness of adhesive tape" refers to the average thickness of a total of 25 points obtained by cutting the adhesive tape in five places at 100 mm intervals along the length and across the width, and measuring the thickness of the adhesive layer at five points at 100 mm intervals along the width on each cut surface using a TH-104 paper / film thickness meter (manufactured by Tester Sangyo Co., Ltd.).

[0201] The hardness (type A hardness (Shore A hardness)) of the adhesive tape of this embodiment is not particularly limited and may be appropriately selected depending on the purpose, but is preferably 10 to 90, more preferably 20 to 85, and even more preferably 64 to 85. When the Shore A hardness of the adhesive tape is within the above-mentioned preferred range, the adhesive tape can be easily peeled off again by pulling it off. On the other hand, when the Shore A hardness is less than 10, the adhesive tape may tear when stretched to peel it off, and when it exceeds 90, when the adhesive tape is stretched to peel it off again, the stress required for stretching becomes too high and it may not be possible to peel it off again. The rubber hardness of the adhesive tape is Shore A hardness, and refers to a value measured in accordance with JIS K 6253 using a durometer (spring type rubber hardness tester) (model: GS-719G, manufactured by Techclock Corporation).

[0202] The stress at 25% elongation of the adhesive tape of this embodiment is preferably 0.15 to 82 MPa, more preferably 0.15 to 10 MPa, even more preferably 0.15 to 5 MPa, and most preferably 0.15 to 2 MPa. When the stress at 25% elongation of the adhesive tape is 0.15 MPa to 82 MPa, the adhesive tape can have a suitable adhesive strength, and can be relatively easily peeled off even when stretched and peeled. On the other hand, when the stress at 25% elongation of the adhesive tape is less than 0.15 MPa, the adhesive tape may peel off when a load is applied in the shear direction of the adhesive tape while fixing hard adherends to each other. In addition, when the stress at 25% elongation of the adhesive tape exceeds 82 MPa, the force required to elongate the adhesive tape when peeling it off tends to be excessive. The stress at 25% elongation of adhesive tape refers to the stress value measured when the adhesive tape is punched out into a dumbbell shape with a gauge length of 20 mm and a width of 5 mm, and pulled in the length direction at a tensile speed of 500 mm / min using a Tensilon tensile testing machine (model: RTF-1210, manufactured by A&D Co., Ltd.) under measurement conditions of 23°C and 50% RH, and elongated by 25%.

[0203] The breaking strength of the adhesive tape of the present embodiment is not particularly limited and can be appropriately selected according to the purpose. However, 10 to 100.0 MPa is preferable, 15 to 90.0 MPa is more preferable, 30 to 90.0 MPa is still more preferable, and 40 to 90.0 MPa is particularly preferable. When the breaking strength of the adhesive tape is within the above preferable range, it is possible to suppress the adhesive tape from being torn when the adhesive tape is quickly stretched and peeled off, and the load for stretching the adhesive tape does not become excessive, so that the re-peeling operation by peeling becomes easy. On the other hand, when the breaking strength of the adhesive tape is less than 10 MPa, the adhesive tape may be torn when the adhesive tape is quickly stretched and peeled off. When it exceeds 100.0 MPa, when trying to stretch and re-peel the adhesive tape, it may not be stretched sufficiently and may not be re-peeled. It should be noted that the force required when stretching and deforming the adhesive tape also depends on the thickness of the adhesive tape. For example, when trying to stretch and re-peel an adhesive tape with a thick thickness and a high breaking strength, it may not be stretched sufficiently and may not be re-peeled. The breaking strength of the adhesive tape refers to the stress value measured when the adhesive tape is punched into a dumbbell shape with a marked length of 20 mm and a width of 5 mm, and pulled in the length direction at a tensile speed of 500 mm / min using a tensilon tensile tester (model: RTF-1210, manufactured by A&D Company, Limited) under the conditions of a measurement atmosphere of 23°C and 50% RH until it breaks.

[0204] The breaking elongation of the pressure-sensitive adhesive tape of the present embodiment is not particularly limited and can be appropriately selected according to the purpose, but is preferably 400 to 2000%, more preferably 500 to 1800%, and even more preferably 600 to 1200%. If the breaking elongation of the pressure-sensitive adhesive tape is 400% or more, even if the pressure-sensitive adhesive tape is firmly attached to the adherend, when the pressure-sensitive adhesive tape is peeled off again, the stress for stretching the tape in the horizontal to vertical direction relative to the adherend surface is not too large, and the pressure-sensitive adhesive tape can be easily peeled off without excessive stretching when peeled off. In addition, if the breaking elongation is 2000% or less, when the pressure-sensitive adhesive tape is peeled off again, the stretching distance in the horizontal to vertical direction relative to the adherend surface is not too long, and work can be done in a small space. On the other hand, if the breaking elongation is less than 500%, when the adhesive tape is to be peeled off again, it may break when stretched horizontally to vertically relative to the application surface of the adherend, and the tape may not be able to be peeled off. If the breaking elongation exceeds 1300%, when the adhesive tape is to be peeled off again, the stretching distance horizontally to vertically relative to the application surface of the adherend becomes too long, which may result in poor workability. The breaking elongation of adhesive tape refers to the tensile elongation percentage measured when the adhesive tape is punched out into a dumbbell shape with a gauge length of 20 mm and a width of 5 mm, and pulled in the length direction at a tensile speed of 500 mm / min using a Tensilon tensile testing machine (model: RTF-1210, manufactured by A&D Co., Ltd.) under measurement conditions of 23°C and 50% RH until breaking.

[0205] The adhesive tape of this embodiment can be preferably peeled off by pulling it in a direction perpendicular to the surface of the adherend (90° direction) under specified conditions. Specifically, the adhesive tape of this embodiment has the evaluation result of "90° stretch peel evaluation" described in the Examples section below, in which "the adhesive tape breaks 0 times out of 3 times" or "the adhesive tape breaks 1 time out of 3 times, and / or the area of ​​the adhesive layer composition remaining on the adherend is less than 1 / 5 of the initial application area." When the adhesive tape has such physical properties, it can be removed from the adherend more easily and more quickly.

[0206] The pressure-sensitive adhesive tape also has excellent impact resistance. Impact resistance can be confirmed, for example, by the method described in "Evaluation of Impact Resistance" in the Examples section below. In the evaluation of impact resistance, the height of the impact point at which the pressure-sensitive adhesive tape peels off or breaks can be appropriately selected within a range that does not impair the effects of the present invention, but is preferably more than 30 cm, more preferably 40 cm or more, even more preferably 50 cm or more, and particularly preferably 60 cm or more. If the height is 30 cm or less, there is a tendency that sufficient impact resistance cannot be obtained.

[0207] The 180° peel adhesive strength of the pressure-sensitive adhesive tape is not particularly limited and may be appropriately selected depending on the purpose, but is preferably 3 to 50 N / 20 mm, more preferably 10 to 50 N / 20 mm, and even more preferably 15 to 45 N / 20 mm. When the 180° peel adhesive strength is within the above-mentioned preferred range, the pressure-sensitive adhesive tape has a suitable adhesive strength without peeling or slipping from the adherend, and can be easily peeled off when stretched horizontally to vertically relative to the application surface of the adherend and then peeled off again. The 180° peel adhesive strength of the adhesive tape refers to the value measured in accordance with JIS Z 0237.

[0208] <Manufacturing method of adhesive tape> In this embodiment, the method for producing the adhesive tape is not particularly limited and can be appropriately selected from known methods. The method for producing the adhesive tape of this embodiment preferably includes an adhesive layer forming step, more preferably includes a base layer forming step and a lamination step as necessary, and further includes other layer forming steps as necessary. The adhesive tape can also be produced by a multi-layer simultaneous formation step in which the adhesive layer forming step and the base layer forming step are performed simultaneously.

[0209] The adhesive layer forming step is not particularly limited as long as it can form an adhesive layer, and can be appropriately selected according to the purpose. For example, the adhesive layer can be formed on the surface of a release sheet by a heat press method, a casting method by extrusion molding, a uniaxial stretching method, a sequential secondary stretching method, a simultaneous biaxial stretching method, an inflation method, a tube method, a calendar method, a solution method, or the like, using the adhesive layer composition forming the above-mentioned adhesive layer. Among these, the casting method by extrusion molding and the solution method are preferred. In addition to the essential components of the silicone composite filler, microballoons, and adhesive resin, the adhesive layer composition may contain acrylic-modified silicone, other optional components of the adhesive layer, or a known solvent. Each component contained in the adhesive layer composition is prepared so that the contents of the essential components (silicone composite filler, microballoons, and adhesive resin), acrylic-modified silicone, and optional components of the adhesive layer in the resulting adhesive layer are each within a predetermined range.

[0210] The release sheet is not particularly limited and can be appropriately selected depending on the purpose, and examples thereof include paper such as kraft paper, glassine paper, and wood-free paper; resin films such as polyethylene, polypropylene (biaxially oriented polypropylene (OPP), uniaxially oriented polypropylene (CPP)), and polyethylene terephthalate (PET); laminated paper in which the above-mentioned paper and a resin film are laminated together; and the above-mentioned paper that has been subjected to a sealing treatment with clay or polyvinyl alcohol or the like and one or both sides of which has been subjected to a release treatment with a silicone-based resin or the like. These may be used alone or in combination of two or more types.

[0211] The above-mentioned base layer forming step is not particularly limited as long as the base layer can be formed, and can be appropriately selected according to the purpose. For example, the above-mentioned base layer forming base composition can be used to form the base layer, and examples thereof include a heat press method, 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, a calendar method, and a solution method. These methods may be used alone or in combination of two or more. Among these, the cast method by extrusion molding, the inflation method, the tube method, the calendar method, and the solution method are preferred in terms of imparting suitable flexibility and extensibility to the base layer. The base composition may contain the above-mentioned base material, other optional components of the base layer, or a known solvent (such as an organic solvent). The base layer may also be surface-treated for the purpose of further improving adhesion to the adhesive layer. The above-mentioned surface treatment method is not particularly limited, and can be appropriately selected from known methods as long as it does not impair the properties of the adhesive tape. Examples of the surface treatment method include sandblasting, surface polishing / rubbing, corona discharge treatment, chromic acid treatment, flame treatment, hot air treatment, ozone treatment, ultraviolet irradiation treatment, and oxidation treatment.

[0212] The lamination step is a step of laminating the base material layer and the adhesive layer when the base material layer is provided. The method of laminating the base material layer and the adhesive layer is not particularly limited and can be appropriately selected from known methods, for example, a method of pressing and laminating the adhesive layer and the base material layer in a state of being attached to the release sheet formed in the adhesive layer forming step.

[0213] <Applications of adhesive tape> The adhesive tape of this embodiment can be suitably used for component fixing or temporary fixing in various industrial fields, such as fixing metal plates to each other or fixing exterior parts to housings that make up relatively large electronic devices such as flat-screen televisions, home appliances, and office automation equipment, and fixing exterior parts and rigid parts such as batteries to relatively small electronic devices such as portable electronic terminals, cameras, and personal computers, as well as for applications such as labels that display product information.

[0214] Although the embodiment of the present invention has been explained above, the adhesive tape of the present invention is not limited to the above example and can be modified as appropriate. EXAMPLES

[0215] The present invention will be described in more detail below with reference to examples, but the present invention is not limited to the following examples. Measurements and evaluations of the adhesive tapes obtained in each example and comparative example were carried out according to the following methods.

[0216] (Method of evaluating adhesive tape) (1) Measurement of the breaking strength and breaking elongation of the base layer Each base layer was punched out into a dumbbell shape with a gauge length of 20 mm and a width of 5 mm, and the base layer was pulled in the length direction at a tensile speed of 500 mm / min using a Tensilon tensile tester (model: RTF-1210, manufactured by A&D Co., Ltd.) under the conditions of a measurement atmosphere of 23°C and 50% RH, to measure the breaking strength and breaking elongation of the base layer. The results are shown in Table 1 below.

[0217] (2) Rubber hardness measurement The Type A hardness (Shore A) of each adhesive tape was measured in accordance with JIS K 6253 using a durometer (spring type rubber hardness tester) (model: GS-719G, manufactured by Techlock Corporation).

[0218] (3) Measurement of the thickness of the base layer and the adhesive layer The base layer and adhesive layer were cut lengthwise at 5 locations at 100 mm intervals and widthwise at 5 locations, and the thickness of each cut surface was measured at 5 locations at 100 mm intervals in the widthwise direction using a TH-104 thickness measuring instrument for paper and film (manufactured by Tester Sangyo Co., Ltd.). The average value of the total 25 thicknesses was taken as the thickness of the base layer and adhesive layer.

[0219] (4) Measurement of average particle size and number average primary particle size (Measurement of average particle size) The average particle size of the silicone composite filler particles and the microballoon particles used in the pressure-sensitive adhesive composition was measured using a measuring device (Microtrac) that uses a laser diffraction scattering method. (Measurement of number average primary particle size) The adhesive tape cooled under liquid nitrogen was cut at three random locations with a microtome, and three pieces were used as samples. Then, a photograph was taken of each sample at a magnification of 400 times using a scanning electron microscope, and from the three photographs, the hollow particles were selected as microballoons and the solid particles were selected as silicone composite fillers. Then, the cross-sectional areas of the hollow and solid bodies calculated by binarization (e.g., Otsu's binarization) using image analysis software were regarded as the area of ​​a circle, and the circle-equivalent diameters of the hollow and solid bodies were measured. Then, the total number of hollow and solid bodies in the three photographs and the corresponding circle-equivalent diameters were calculated, and the number-average primary average particle diameters of the silicone composite filler and the microballoons were calculated from the following formulas (A) and (B).

number

number

[0220] (5) Evaluation of 90° stretch peel Each adhesive tape was cut to a length of 70 mm and a width of 10 mm. A clean, smooth-surfaced aluminum plate (length 150 mm, width 70 mm, thickness 2 mm, alloy number A1050) was attached to one side of the adhesive tape under conditions of an atmosphere of 23°C and 50% RH, with a length of 50 mm and a width of 10 mm protruding as a gripping part. Next, a clean, smooth-surfaced acrylic plate (length 150 mm, width 70 mm, thickness 2 mm, Acrylite L, color tone: colorless, manufactured by Mitsubishi Rayon Co., Ltd.) was attached to the side of the adhesive tape opposite to the side to which the aluminum plate was attached, and the laminated structure of the aluminum plate, the adhesive tape, and the acrylic plate was pressed by moving a roller back and forth once while applying a load of 5 kg to the laminated structure, and then left to stand for 24 hours under conditions of an atmosphere of 23°C and 50% RH to prepare a test specimen. Under conditions of an atmosphere of 23°C and 50% RH, the gripping portion of the adhesive tape in the test piece was stretched at 90° (vertical direction) on the acrylic plate side relative to the adhesive tape side at a tensile speed of 500 mm / min using a Tensilon tensile tester (model: RTF-1210, manufactured by A&D Co., Ltd.) with a load limiter set to 50 N. The stress measured by the Tensilon tensile tester was recorded. In addition, for appearance evaluation, the occurrence of breakage of the adhesive tape was visually confirmed by checking the degree of residual adhesive layer composition on the adherend (at least one of the aluminum plate and the acrylic plate) after peeling off the adhesive tape. The test was carried out three times by the above method, and the removability (stretching and peeling in the vertical direction) was evaluated based on the following evaluation criteria. The results are shown in Tables 1 to 3 below. [Appearance evaluation criteria] ⊚: The adhesive tape broke zero times out of three times, and no adhesive layer composition remained on the adherend. ◯: The adhesive tape broke once out of three times, and / or the area of ​​the adhesive layer composition remaining on the adherend was less than 1 / 5 of the initial application area. Δ: The adhesive tape broke once out of three times, the adhesive tape did not stretch, and the area of ​​the adhesive tape remaining on the adherend was 1 / 5 or more of the initial applied area. ×: The adhesive tape broke two or more times out of three times, and / or the adhesive tape did not stretch and could not be peeled off again. In addition, ◎ and ○ indicate that there is no problem with use.

[0221] (6) Evaluation of adhesive strength The 180° peel adhesive strength was measured in accordance with JIS Z 0237. Specifically, each adhesive tape was cut to a length of 150 mm and a width of 20 mm, and one side of the adhesive tape was backed with a PET film having a thickness of 25 μm. Next, the other side of the adhesive tape was attached to a stainless steel plate (length 100 mm, width 30 mm, thickness 3 mm) under conditions of an atmosphere of 23° C. and 50% RH, and the laminated structure of the adhesive tape and the stainless steel plate was pressed by a roller in one reciprocating motion while applying a load of 2 kg to the laminated structure, and then the laminated structure was left to stand for 1 hour under conditions of an atmosphere of 23° C. and 50% RH to prepare a test specimen. The adhesive tape of the test piece was stretched in the 180° direction (horizontal direction) at a tensile speed of 300 mm / min using a Tensilon tensile tester (model: RTF-1210, manufactured by A&D Co., Ltd.) under conditions of an atmosphere of 23°C and 50% RH, and the 180° peel adhesive strength of the adhesive tape was measured.

[0222] (7) Evaluation of retention strength One adhesive surface of the adhesive tape was backed with a 25 μm thick polyethylene terephthalate film, and the tape was cut to a width of 20 mm and a length of 100 mm. The tape was placed on a clean, smooth-surfaced stainless steel plate (hairline-polished with No. 360 waterproof abrasive paper) in an atmosphere of 23° C. and 50% RH so that the surface area was 20 mm×20 mm. The upper surface was pressed by rolling a 2 kg roller back and forth once, and the tape was left in an environment of 23° C. for 1 hour to prepare a test piece. Then, with the stainless steel plate constituting the test piece fixed, a load of 1 kg was applied to the adhesive tape in an environment of 70° C., and the time from when the adhesive tape fell from the stainless steel plate was measured. If the adhesive tape did not fall even after 15 hours or more, it was marked as “◯”, and if the adhesive tape fell within 15 hours, it was marked as “×”.

[0223] (8) Impact resistance evaluation As shown in FIG. 1, two pieces of each adhesive tape 1 cut to a length of 20 mm and a width of 2 mm were prepared. The adhesive tape 1 was attached in parallel to an aluminum plate 11 (length 50 mm, width 25 mm, thickness 0.8 mm, alloy number A1050) with an interval of 40 mm. An acrylic plate 12 (length 50 mm, width 25 mm, thickness 2.5 mm, Acrylite L, color tone: colorless, manufactured by Mitsubishi Rayon Co., Ltd.) was attached to the opposite side of the adhesive tape 1, and pressure was applied by rolling it back and forth once with a roller while applying a load of 2 kg to the adhesive tape 1, and the adhesive tape 12 was left to stand for 24 hours under the conditions of an atmosphere of 40° C. and 50% RH to prepare a test piece 10. Note that FIG. 1 is a schematic plan view of the test piece 10 as seen from the acrylic plate 12 side, and the position of the acrylic plate 12 is shifted for the sake of explanation, but in reality, the outer periphery of the acrylic plate 12 and the outer periphery of the aluminum plate 11 are arranged so as to overlap in plan view. Next, as shown in FIG. 2 (left), assuming an article in which an adhesive tape is attached to an adherend, a U-shaped measurement table 22 (length t: 150 mm, width (no symbol in the figure): 100 mm, height h: 45 mm, thickness w: 5 mm, made of aluminum) was placed on the base of a DuPont impact tester (manufactured by Tester Sangyo Co., Ltd.) with a 300 g stainless steel load 21 attached to the acrylic plate 12 side of the test piece 10, and the test piece 10 was dropped onto the U-shaped measurement table 22 with the aluminum plate 11 side facing downward under conditions of an atmosphere of 23°C and 50% RH. The arrow X in FIG. 2 (left) indicates the dropping direction of the test piece 10 equipped with the load 21. And FIG. 2 (right) is a schematic diagram showing the state in which the test piece 10 has been dropped onto the U-shaped measurement table 22 with the aluminum plate 11 side facing downward. The top of the U-shaped measuring platform 22 in the height direction was set as the reference point O, and the height H from the reference point O to the position P of the adhesive surface of the test piece 10 with the load 21 was changed by 10 cm starting from 10 cm, and the test piece 10 was dropped five times at each height, and the height H at which peeling or destruction of the adhesive tape 1 on the test piece 10 was observed was measured.

[0224] (9) Evaluation of cutting processability In a thermostatic chamber at 23°C and 50% RH, the adhesive layer or adhesive tape obtained below was attached to both sides of a 2 mm thick acrylic plate (mirror finish, "Acrylite" manufactured by Mitsubishi Rayon Co., Ltd.) in accordance with the adhesive strength evaluation method of JIS Z0237:2000. The acrylic plate to which the adhesive layer or adhesive tape was attached was cut with a high-speed cutter, and the cut end surface of the adhesive layer or adhesive tape was visually observed, and the cutting processability was evaluated according to the following criteria. * The cut area reattached. (In the case of rubber-based tape, the adhesive tape itself stretches, causing dimensional defects.) × The cut area did not reattach. (Even with rubber-based tape, it was possible to cut without stress.) (10) Measurement of friction force The frictional force of the adhesive layer of the adhesive tape (23°C) was measured using a measuring device defined in JIS K7125. The sliding piece was a stainless steel plate (40 cm 2 A canvas was prepared by bonding the felt surface and the cotton canvas #9 facing each other with double-sided tape (DIC #8800CH). The cotton canvas #9 referred to here is No. 9 cotton canvas [(based on the old JIS L3102) with a twist of yarn (warp 10 / 2, weft 10 / 3), density (warp 44-48 threads / inch, weft 33-37 threads / inch), weight 510 g / m 2 )]. Next, the adhesive tape to be used for evaluation was cut to a size of 100 mm wide x 200 mm long, and fixed on a smooth and horizontal test table so that the adhesive layer surface of the adhesive tape to be measured was facing upward. The stress value was measured when the sliding piece slid over the adhesive layer surface of the adhesive tape to be measured. Note that the stress value obtained by this measurement method is in a state where the static friction force is continuously measured because the friction force against the adhesive layer surface is high. For this reason, a graph of the stress value and the moving distance of the sliding piece was created, and the stress value for a moving distance of 50 mm was extracted from the moving distance range where the stress value was relatively stable, and the arithmetic average of the peak values ​​of the extracted stress values ​​was taken as the friction force.

[0225] (Making adhesive tape) Next, the materials used in the examples and comparative examples are as follows. [Adhesive layer] <Silicone composite filler>, Silicone composite filler (1): Particles with a silicone resin surface and silicone rubber inside (Shin-Etsu Chemical Co., Ltd., KMP-602, average particle size: 30 μm, particle size distribution (D 90 / D 10 ):5.2) was used. Silicone composite filler (2): Particles with a silicone resin surface and silicone rubber inside (Shin-Etsu Chemical Co., Ltd., KMP-601, average particle size: 12 μm, particle size distribution (D 90 / D 10 ):4.4) was used. Silicone rubber filler (1): Particles formed of silicone rubber (particles without silicone resin on the surface) (Shin-Etsu Chemical Co., Ltd., KMP-598, average particle size: 13 μm, particle size distribution (D 90 / D 10 ):4.9) was used.

[0226] <Microballoons> Microballoon (1): A hollow body containing low-boiling point hydrocarbons, with a shell made of polyacrylonitrile and coated with talc (product name: MFL-81GTA, average particle size: 20 μm, true specific gravity: 0.23 g / cm 3 ) Microballoon (2): A hollow body containing low-boiling point hydrocarbons, with a shell made of polyacrylonitrile and coated with calcium carbonate (product name: EMC-40(AS), average particle size: 42μm, true specific gravity: 0.13g / cm 3 ) Microballoon (3): A hollow body containing low-boiling point hydrocarbons, with a shell of polyacrylonitrile, and the shell coated with calcium carbonate (Product name: EMC-80(B) Average particle size: 70 μm, True specific gravity: 0.13 g / cm 3 )

[0227] <Adhesive resin> Acrylic resin (1): In a 1000 ml flask with an argon atmosphere, 500 ml of dry toluene and bis(pentamethylcyclopentadienyl)samarium tetrahydrofuranate complex [(C 5 Me 5 ) 2 A mixed solution was prepared by adding 80 ml of a dry toluene solution containing 0.75 g of SmMe(THF). 12.0 ml of methyl methacrylate (MMA) was added to the mixed solution at 0°C and stirred at 0°C for 30 minutes. 20 ml of the solution was then sampled from the system (Sample 1). After the polymerization of MMA, the polymerization reaction system was cooled to -78°C, and 88.0 ml of n-butyl acrylate (nBA) was added as the second monomer and stirred at -78°C for 3 hours. 20 ml of the solution was then sampled from the system (Sample 2). After the polymerization of nBA, 12.0 ml of MMA was added to the polymerization system as the third monomer at -78°C and the solution was stirred. After the solution became homogeneous, the temperature was raised to 0°C and the solution was further stirred for 1 hour. 50 ml of methanol was added to the obtained reaction mixture and the reaction was carried out at room temperature for 2 hours to terminate the polymerization. The reaction solution after the polymerization was stopped was poured into a large amount of hexane to obtain a white precipitate, and a part of the white precipitate was sampled (sample 3).

[0228] NMR measurement, DSC measurement, and GPC (gel permeation chromatography) measurement were performed on each polymer in the above samples 1 to 3. Then, based on the measurement results, the number average molecular weight (Mn), PMMA / PnBA (polymethyl methacrylate block / polyn-butyl acrylate block) ratio, etc. were obtained, and it was confirmed that the above white precipitate was a triblock copolymer (PMMA-b-PnBA-b-PMMA) of polymethyl methacrylate (PMMA) block-polyn-butyl acrylate (PnBA) block-polymethyl methacrylate (PMMA) block. In addition, it was confirmed that the PMMA block portion of the triblock copolymer (PMMA-b-PnBA-b-PMMA, hereinafter referred to as triblock copolymer (1)) had a syndiotacticity of 71%, a glass transition temperature of 113.7°C, a glass transition temperature of -46.8°C, an Mn of the entire copolymer of 95,936, an Mw / Mn (molecular weight distribution) of 1.09, and a ratio of the polymer blocks of PMMA (11% by weight)-PnBA (78% by weight)-PMMA (11% by weight). The white precipitate obtained above was diluted with ethyl acetate to obtain an acrylic resin solution (1) with a solid content of 45% by mass. Acrylic resin (2): In a reaction vessel equipped with a stirrer, a reflux condenser, a nitrogen inlet tube, a thermometer, and a dropping funnel, 75.94 parts by weight of n-butyl acrylate, 5 parts by weight of 2-ethylhexyl acrylate, 15 parts by weight of cyclohexyl acrylate, 4 parts by weight of acrylic acid, 0.06 parts by weight of 4-hydroxybutyl acrylate, and 200 parts by weight of ethyl acetate were charged, and the mixture (1a) was obtained by heating to 65°C while blowing in nitrogen under stirring. Next, 4 parts by weight of 2,2'-azobisisobutyronitrile solution (solid content 2.5% by weight) dissolved in ethyl acetate was added to the mixture (1a), and the mixture was held at 65°C for 10 hours under stirring to obtain a mixture (1b). Next, the mixture (1b) was diluted with 98 parts by weight of ethyl acetate and filtered through a 200-mesh wire net to obtain an acrylic resin solution (1) having a weight average molecular weight of 1.6 million (polystyrene equivalent).

[0229] <Adhesive layer optional components> Tackifying resin (1) A terpene phenol-based tackifying resin (Tamanol 803L, Arakawa Chemical Industries, Ltd.) was used. Tackifying resin (2) A polymerized rosin ester tackifying resin (D-125, Arakawa Chemical Industries, Ltd.) was used. Tackifying resin (3) A petroleum-based tackifier resin (FTR (registered trademark) 6125, manufactured by Mitsui Chemicals, Inc.) was used. Acrylic modified silicone (1) As the acrylic modified silicone (1), Charine R-770 (product name, manufactured by Nissin Chemical Industry Co., Ltd.; average particle size 350 μm) was used. Acrylic modified silicone (2) As the acrylic modified silicone (2), Charine R-773 (product name, manufactured by Shin-Etsu Chemical Co., Ltd.; average particle size 30 μm) was used.

[0230] [Base material layer] <Material for base material> ·Base material (1) (SIS) A mixture of styrene-isoprene copolymer and styrene-isoprene-styrene copolymer (hereinafter sometimes referred to as "SIS") was used as the substrate material (1). The mixture contained 25% by weight of a structural unit derived from styrene represented by the following chemical formula (5), and the ratio of the styrene-isoprene copolymer to the total amount of the resin composition (1) was 17% by weight. [ka]

[0231] ·Base material (2) (SEEPS) A nitrogen-purged, dried pressure vessel was charged with 3,000 mL of cyclohexane as a solvent and 9.2 mL of 10.5% by mass sec-butyllithium (cyclohexane solution) as an initiator, and the temperature was raised to 60°C. Then, 100 mL of styrene was added and polymerization was carried out for 60 minutes. Then, 270 mL of isoprene and 350 mL of butadiene were added at the same temperature, and the mixture was reacted for 90 minutes. Then, 100 mL of styrene was added at the same temperature, and the mixture was polymerized for 60 minutes. The polymerization was then terminated with 0.52 mL of methanol, and a polymerization reaction liquid containing a block copolymer was obtained. To this reaction mixture, 29.3 g of palladium carbon (palladium loading: 5% by mass) was added as a hydrogenation catalyst, and the hydrogenation reaction was carried out for 10 hours at a hydrogen pressure of 2 MPa and 150° C. After cooling and releasing the pressure, the palladium carbon was removed by filtration, and the filtrate was concentrated and further dried in vacuum to obtain a substrate material (2). The obtained substrate material (2) had a styrene content of 30 mass %, a weight average molecular weight of 98,000, a molecular weight distribution of 1.03, and a hydrogenation rate of 98%.

[0232] A method for preparing a composition for forming an adhesive layer used in the present examples and comparative examples will be described below. [Method of preparing the adhesive layer composition] Method for preparing the adhesive layer composition (1) After adding 36 parts by mass of tackifier resin (1) to 100 parts by mass of the solid content of the acrylic resin (1), 17.5 parts by mass of silicone composite filler (1), 9.8 parts by mass of microballoons (1), and ethyl acetate were added and stirred until homogenous, to obtain a composition for adhesive layer (1) with a solid content of 45%.

[0233] Method for preparing adhesive layer composition (2) 100 parts by weight of the solid content of the acrylic resin (2) was mixed and stirred with 5 parts by weight of a polymerized rosin ester tackifier resin (D-125, Arakawa Chemical Industries Co., Ltd.) and 15 parts by weight of a petroleum tackifier resin (FTR (registered trademark) 6125, Mitsui Chemicals Co., Ltd.), and then 17.5 parts by weight of a silicone composite filler (1), 9.8 parts by weight of a microballoon (1), and ethyl acetate were added and stirred to be uniform to prepare a mixture (1) having a solid content of 38%. Next, 1.3 parts by weight of a crosslinking agent (Barnock D-40, DIC Corporation; trimethylolpropane adduct of tolylene diisocyanate, isocyanate group content 7% by weight, non-volatile content 40% by weight) was added to 100 parts by weight of the mixture (1), and the mixture was stirred and mixed to be uniform to obtain a composition for adhesive layer (2).

[0234] Method for preparing the adhesive layer composition (3) As with the adhesive layer composition (1), 36 parts by mass of tackifier resin (1) was added to 100 parts by mass of the solid content of the acrylic resin (1), and then 17.5 parts by mass of silicone composite filler (2), 9.8 parts by mass of microballoons (1), and ethyl acetate were added and stirred until homogenous, thereby obtaining an adhesive layer composition (3) having a solid content of 45%.

[0235] Method for preparing the adhesive layer composition (4) As with the adhesive layer composition (1), 36 parts by mass of tackifier resin (1) was added to 100 parts by mass of the solid content of the acrylic resin (1), and then 17.5 parts by mass of silicone composite filler (1), 4.2 parts by mass of microballoons (1), and ethyl acetate were added and stirred until homogenous, thereby obtaining an adhesive layer composition (4) having a solid content of 45%.

[0236] Method for preparing the adhesive layer composition (5) As with the adhesive layer composition (1), 36 parts by mass of tackifier resin (1) was added to 100 parts by mass of the solid content of the acrylic resin (1), and then 17.5 parts by mass of silicone composite filler (1), 17.5 parts by mass of microballoons (1), and ethyl acetate were added and stirred until homogenous, thereby obtaining an adhesive layer composition (5) having a solid content of 45%.

[0237] ·Adhesive layer composition (6) As with the adhesive layer composition (1), 36 parts by mass of tackifier resin (1) was added to 100 parts by mass of the solid content of the acrylic resin (1), and then 17.5 parts by mass of silicone composite filler (1), 17.5 parts by mass of microballoons (1), 1 part by mass of acrylic modified silicone (1), and ethyl acetate were added and stirred until homogenous, thereby obtaining an adhesive layer composition (6) having a solid content of 45%.

[0238] ·Adhesive layer composition (7) 100 parts by weight of the solid content of the acrylic resin (2) was mixed and stirred with 5 parts by weight of a polymerized rosin ester tackifier resin (D-125, Arakawa Chemical Industries Co., Ltd.) and 15 parts by weight of a petroleum tackifier resin (FTR (registered trademark) 6125, Mitsui Chemicals Co., Ltd.), and then 17.5 parts by weight of a silicone composite filler (1), 9.8 parts by weight of a microballoon (1), 1 part by weight of an acrylic modified silicone (1), and ethyl acetate were added and stirred to be uniform to prepare a mixture (2) having a solid content of 38%. Next, 1.3 parts by weight of a crosslinking agent (Burnoc D-40, DIC Corporation; trimethylolpropane adduct of tolylene diisocyanate, isocyanate group content 7% by weight, non-volatile content 40% by weight) was added to 100 parts by weight of the mixture (2), and the mixture was stirred and mixed to be uniform to obtain a composition for adhesive layer (7).

[0239] ·Adhesive layer composition (8) As with the adhesive layer composition (1), 36 parts by mass of tackifier resin (1) was added to 100 parts by mass of the solid content of the acrylic resin (1), and then 28 parts by mass of silicone composite filler (2), 10.1 parts by mass of microballoons (2), and ethyl acetate were added and stirred until homogenous to obtain an adhesive layer composition (8) having a solid content of 45%.

[0240] ·Adhesive layer composition (9) As with the adhesive layer composition (1), 36 parts by mass of tackifier resin (1) was added to 100 parts by mass of the solid content of the acrylic resin (1), and then ethyl acetate was added and stirred to make a homogeneous mixture to obtain an adhesive layer composition (9) having a solid content of 45%.

[0241] ·Adhesive layer composition (10) After adding 36 parts by mass of tackifier resin (1) to 100 parts by mass of the solid content of the acrylic resin (1), 7.7 parts by mass of microballoons (1) and ethyl acetate were added and stirred until homogenous to obtain a composition for adhesive layer (10) with a solid content of 45%.

[0242] ·Adhesive layer composition (11) After adding 36 parts by mass of tackifier resin (1) to 100 parts by mass of the solid content of the acrylic resin (1), 17.5 parts by mass of silicone composite filler (1) and ethyl acetate were added and stirred until homogenous to obtain a composition for adhesive layer (11) with a solid content of 45%.

[0243] Method for preparing the adhesive layer composition (12) After adding 36 parts by mass of tackifier resin (1) to 100 parts by mass of the solid content of the acrylic resin (1), 17.5 parts by mass of silicone composite filler (1), 6.0 parts by mass of microballoons (3), and ethyl acetate were added and stirred until homogenous, to obtain a composition for adhesive layer (12) with a solid content of 45%.

[0244] Method for preparing the adhesive layer composition (13) After adding 36 parts by mass of tackifier resin (1) to 100 parts by mass of the solid content of the acrylic resin (1), 17.5 parts by mass of silicone composite filler (2), 26 parts by mass of microballoons (1), and ethyl acetate were added and stirred until homogenous, to obtain a composition for adhesive layer (13) with a solid content of 45%.

[0245] Method for preparing the adhesive layer composition (14) After adding 36 parts by mass of tackifier resin (1) to 100 parts by mass of the solid content of the acrylic resin (1), 17.5 parts by mass of silicone rubber filler (1), 9.8 parts by mass of microballoons (1), and ethyl acetate were added and stirred until homogenous, to obtain a composition for adhesive layer (14) with a solid content of 45%.

[0246] "Manufacturing adhesive tape" Example 1 The substrate material (1) was diluted with toluene to prepare a coating solution (1) so that the solid content was 30% by mass. The coating solution (1) was applied to a release liner (Film Vina 75E-0010GT, manufactured by Fujimori Kogyo Co., Ltd., hereinafter the same) with an applicator so that the thickness after drying was 50 μm, and the substrate layer was prepared by drying at 65 ° C for 15 minutes. Next, the adhesive layer composition (1) was applied to a release liner (Film Vina 75E-0010GT, manufactured by Fujimori Kogyo Co., Ltd., hereinafter the same) with an applicator so that the thickness after drying was 100 μm, and the adhesive layer was prepared by drying at 85 ° C for 3 minutes. Next, the substrate layer was subjected to corona treatment so that the wet tension on both sides was 56 mN / m, and then the adhesive layer was attached to both sides, and the laminate of the substrate layer and the adhesive layer was pressed at 0.2 MPa to laminate, thereby producing the adhesive tape of Example 1. The resulting adhesive tape was evaluated by the above-mentioned method, and the results are shown in Table 1. Furthermore, the number average primary particle diameters of the silicone modified filler and microballoons present in the adhesive layer of the adhesive tape obtained in Example 1 were measured according to the above-mentioned method.

[0247] Example 2 The coating solution (2) was prepared by diluting the substrate material (2) with toluene to a solid content of 20% by mass in the same manner as in Example 1. The coating solution (1) was applied to a release liner (Film Vina 75E-0010GT, manufactured by Fujimori Kogyo Co., Ltd., hereinafter the same) with an applicator so that the thickness after drying was 50 μm, and the substrate layer was prepared by drying at 65 ° C for 15 minutes. Next, the adhesive layer composition (1) was applied to a release liner (Film Vina 75E-0010GT, manufactured by Fujimori Kogyo Co., Ltd., hereinafter the same) with an applicator so that the thickness after drying was 100 μm, and the adhesive layer was prepared by drying at 85 ° C for 3 minutes. Next, the substrate layer was subjected to corona treatment so that the wet tension on both sides was 56 mN / m, and then the adhesive layer was attached to both sides, and the laminate of the substrate layer and the adhesive layer was pressed at 0.2 MPa to laminate, thereby producing an adhesive tape of Example 2. The obtained pressure-sensitive adhesive tape was evaluated by the above-mentioned method, and the results are shown in Table 1. In addition, the number average primary particle diameters of the silicone-modified filler and microballoons present in the pressure-sensitive adhesive layer of the pressure-sensitive adhesive tape obtained in Example 2 were measured according to the above-mentioned method.

[0248] Example 3 The substrate material (1) was diluted with toluene to prepare a coating solution (1) so that the solid content was 30% by mass. The coating solution (1) was applied to a release liner (Film Vina 75E-0010GT, manufactured by Fujimori Kogyo Co., Ltd., hereinafter the same) with an applicator so that the thickness after drying was 50 μm, and the substrate layer was prepared by drying at 65 ° C for 15 minutes. Next, the adhesive layer composition (2) was applied to a release liner (Film Vina 75E-0010GT, manufactured by Fujimori Kogyo Co., Ltd., hereinafter the same) with an applicator so that the thickness after drying was 100 μm, and the adhesive layer was prepared by drying at 85 ° C for 3 minutes. Next, the base layer was subjected to a corona treatment so that the wet tension on both sides thereof was 56 mN / m, and then the adhesive layer was attached to both sides, and the laminate of the base layer and the adhesive layer was pressed at 0.2 MPa to be laminated, and then cured in an environment of 40° C. for 2 days to produce an adhesive tape of Example 3. The obtained adhesive tape was evaluated by the above-mentioned method, and the results are shown in Table 1. In addition, the number average primary particle diameters of the silicone-modified filler and microballoons present in the adhesive layer of the adhesive tape obtained in Example 3 were measured by the above-mentioned method.

[0249] Example 4 An adhesive tape of Example 4 was produced in the same manner as in Example 1, except that adhesive layer composition (3) was used instead of adhesive layer composition (1). The resulting adhesive tape was evaluated by the above-mentioned method, and the results are shown in Table 1. In addition, the number average primary particle diameters of the silicone-modified filler and microballoons present in the adhesive layer of the adhesive tape obtained in Example 4 were measured according to the above-mentioned method.

[0250] Example 5 The coating solution (2) was prepared by diluting the substrate material (2) with toluene to a solid content of 20% by mass in the same manner as in Example 1. The coating solution (2) was applied to a release liner (Film Vina 75E-0010GT, manufactured by Fujimori Kogyo Co., Ltd., hereinafter the same) with an applicator so that the thickness after drying was 100 μm, and the substrate layer was prepared by drying at 65 ° C for 15 minutes. Next, the adhesive layer composition (4) was applied to a release liner (Film Vina 75E-0010GT, manufactured by Fujimori Kogyo Co., Ltd., hereinafter the same) with an applicator so that the thickness after drying was 75 μm, and the adhesive layer was prepared by drying at 85 ° C for 3 minutes. Next, the substrate layer was subjected to corona treatment so that the wet tension on both sides was 56 mN / m, and then the adhesive layer was attached to both sides, and the laminate of the substrate layer and the adhesive layer was pressed at 0.2 MPa to laminate, thereby producing an adhesive tape of Example 5. The obtained pressure-sensitive adhesive tape was evaluated by the above-mentioned method, and the results are shown in Table 1. In addition, the number average primary particle diameters of the silicone-modified filler and microballoons present in the pressure-sensitive adhesive layer of the pressure-sensitive adhesive tape obtained in Example 5 were measured according to the above-mentioned method.

[0251] Example 6 An adhesive tape of Example 6 was produced in the same manner as in Example 1, except that adhesive layer composition (5) was used instead of adhesive layer composition (1). The resulting adhesive tape was evaluated by the above-mentioned method, and the results are shown in Table 1. In addition, the number average primary particle diameters of the silicone-modified filler and microballoons present in the adhesive layer of the adhesive tape obtained in Example 6 were measured according to the above-mentioned method.

[0252] Example 7 An adhesive tape of Example 6 was produced in the same manner as in Example 2, except that adhesive layer composition (6) was used instead of adhesive layer composition (1). The resulting adhesive tape was evaluated by the above-mentioned method, and the results are shown in Table 1. In addition, the number average primary particle diameters of the silicone-modified filler and microballoons present in the adhesive layer of the adhesive tape obtained in Example 7 were measured according to the above-mentioned method.

[0253] Example 8 The adhesive layer composition (1) was applied onto a release liner (Film Bina 75E-0010GT, manufactured by Fujimori Kogyo Co., Ltd., the same applies below) with an applicator so that the thickness after drying would be 150 μm, and then dried at 85° C. for 3 minutes to produce an adhesive tape of Example 8. The obtained adhesive tape was evaluated by the above-mentioned method, and the results are shown in Table 1. In addition, the number average primary particle diameters of the silicone modified filler and microballoons present in the adhesive layer of the adhesive tape obtained in Example 8 were measured according to the above-mentioned method.

[0254] Example 9 The substrate material (2) was diluted with toluene to prepare a coating solution (2) having a solid content of 20% by mass. The coating solution (2) was applied to a release liner (Film Vina 75E-0010GT, manufactured by Fujimori Kogyo Co., Ltd., hereinafter the same) with an applicator so that the thickness after drying was 50 μm, and the substrate layer was prepared by drying at 65 ° C for 15 minutes. Next, the adhesive layer composition (8) was applied to a release liner (Film Vina 75E-0010GT, manufactured by Fujimori Kogyo Co., Ltd., hereinafter the same) with an applicator so that the thickness after drying was 100 μm, and the adhesive layer was prepared by drying at 85 ° C for 3 minutes. Next, the base layer was subjected to a corona treatment so that the wet tension on both sides thereof was 56 mN / m, and then the adhesive layer was attached to both sides, and the laminate of the base layer and the adhesive layer was pressed at 0.2 MPa to be laminated, and then cured in an environment of 40° C. for 2 days to produce an adhesive tape of Example 9. The obtained adhesive tape was evaluated by the above-mentioned method, and the results are shown in Table 1. In addition, the number average primary particle diameters of the silicone-modified filler and microballoons present in the adhesive layer of the adhesive tape obtained in Example 9 were measured by the above-mentioned method.

[0255] Comparative Example 1 The substrate material (2) was diluted with toluene to prepare a coating solution (2) having a solid content of 20% by mass. The coating solution (2) was applied to a release liner (Film Vina 75E-0010GT, manufactured by Fujimori Kogyo Co., Ltd., hereinafter the same) with an applicator so that the thickness after drying was 100 μm, and the coating solution (2) was dried at 65 ° C for 15 minutes to prepare a substrate layer. Next, the adhesive layer composition (9) was applied to a release liner (Film Vina 75E-0010GT, manufactured by Fujimori Kogyo Co., Ltd., hereinafter the same) with an applicator so that the thickness after drying was 75 μm, and the adhesive layer was dried at 85 ° C for 3 minutes to prepare an adhesive layer. Next, the substrate layer was subjected to a corona treatment so that the wet tension on both sides was 56 mN / m, and then the adhesive layer was attached to both sides, and the laminate of the substrate layer and the adhesive layer was pressed at 0.2 MPa to laminate, thereby producing an adhesive tape of Comparative Example 1. The obtained pressure-sensitive adhesive tape was evaluated by the above-mentioned method, and the results are shown in Table 1. In addition, the number average primary particle diameters of the silicone-modified filler and microballoons present in the pressure-sensitive adhesive layer of the pressure-sensitive adhesive tape obtained in Comparative Example 1 were measured according to the above-mentioned method.

[0256] Comparative Example 2 An adhesive tape of Comparative Example 2 was produced in the same manner as in Comparative Example 1, except that composition for adhesive layer (10) was used instead of composition for adhesive layer (9). The obtained adhesive tape was evaluated by the above-mentioned method, and the results are shown in Table 2. In addition, the number average primary particle diameters of the silicone-modified filler and microballoons present in the adhesive layer of the adhesive tape obtained in Comparative Example 2 were measured according to the above-mentioned method.

[0257] Comparative Example 3 An adhesive tape of Comparative Example 3 was produced in the same manner as in Comparative Example 1, except that composition for adhesive layer (11) was used instead of composition for adhesive layer (9). The obtained adhesive tape was evaluated by the above-mentioned method, and the results are shown in Table 2. In addition, the number average primary particle diameters of the silicone-modified filler and microballoons present in the adhesive layer of the adhesive tape obtained in Comparative Example 3 were measured according to the above-mentioned method.

[0258] Comparative Example 4 An adhesive tape of Comparative Example 4 was produced in the same manner as in Comparative Example 1, except that composition for adhesive layer (12) was used instead of composition for adhesive layer (9). The obtained adhesive tape was evaluated by the above-mentioned method, and the results are shown in Table 2. In addition, the number average primary particle diameters of the silicone-modified filler and microballoons present in the adhesive layer of the adhesive tape obtained in Comparative Example 4 were measured according to the above-mentioned method.

[0259] Comparative Example 5 An adhesive tape of Comparative Example 5 was produced in the same manner as in Comparative Example 1, except that composition for adhesive layer (13) was used instead of composition for adhesive layer (9). The obtained adhesive tape was evaluated by the above-mentioned method, and the results are shown in Table 2. In addition, the number average primary particle diameters of the silicone-modified filler and microballoons present in the adhesive layer of the adhesive tape obtained in Comparative Example 5 were measured according to the above-mentioned method.

[0260] Comparative Example 6 An adhesive tape of Comparative Example 6 was produced in the same manner as in Comparative Example 1, except that composition for adhesive layer (14) was used instead of composition for adhesive layer (9). The obtained adhesive tape was evaluated by the above-mentioned method, and the results are shown in Table 2. In addition, the number average primary particle diameters of the silicone-modified filler and microballoons present in the adhesive layer of the adhesive tape obtained in Comparative Example 6 were measured according to the above-mentioned method.

[0261] [Table 1]

[0262] [Table 2] [Industrial Applicability]

[0263] According to the present invention, it is possible to provide an adhesive tape that combines excellent impact resistance with good cuttability. [Explanation of symbols]

[0264] 1 Adhesive tape 11 Aluminum plate 12 Acrylic plate 22 U-shaped measuring table 21 Load

Claims

1. An adhesive tape having an adhesive layer, the adhesive layer contains a silicone composite filler having a number average primary particle diameter of 3 to 45 μm, microballoons having a number average primary particle diameter of 5 to 50 μm, and an adhesive resin; An adhesive tape, characterized in that the content of the silicone composite filler is 10 to 50 parts by mass and the content of the microballoons is 1 to 25 parts by mass relative to 100 parts by mass of the adhesive resin.

2. An adhesive tape having an adhesive layer, The adhesive layer is formed from a composition for adhesive layer containing a silicone composite filler having an average particle size of 10 to 40 μm, microballoons having an average particle size of 10 to 50 μm, and an adhesive resin, and the content of the silicone composite filler is 10 to 50 parts by mass and the content of the microballoons is 1 to 25 parts by mass relative to 100 parts by mass of the adhesive resin.

3. 3. The adhesive tape according to claim 1, wherein the volume ratio of said microballoons to the total volume of said adhesive layer is 5 to 30% by volume.

4. 4. The pressure-sensitive adhesive tape according to claim 1, wherein the microballoons are hollow particles having a surface layer containing a first resin, and an inorganic material is attached to the surface of the surface layer.

5. The adhesive tape according to any one of claims 1 to 4, wherein, when the average thickness of the adhesive layer is taken as 1, a ratio of the number average primary particle diameter of the silicone composite filler to the thickness of the adhesive layer is within a range of 0.1 to 0.

7.

6. The adhesive tape according to any one of claims 1 to 5, wherein, when the average thickness of the adhesive layer is taken as 1, the ratio of the number average primary particle diameter of the microballoons to the thickness of the adhesive layer is within a range of 0.1 to 0.

5.

7. The adhesive layer is formed from a composition for adhesive layer containing a silicone composite filler having an average particle size of 10 to 40 μm, microballoons having an average particle size of 10 to 50 μm, and an adhesive resin, and the composition for adhesive layer further contains an acrylic modified silicone; The pressure-sensitive adhesive tape according to any one of claims 2 to 6, wherein the content of said acrylic-modified silicone is 0.1 to 30 parts by mass per 100 parts by mass of said pressure-sensitive adhesive resin.

8. The adhesive tape according to any one of claims 1 to 7, further comprising a substrate, the adhesive layer being provided on one or both sides of the substrate.

9. The pressure-sensitive adhesive tape according to claim 8, wherein the breaking elongation of the substrate is 400 to 1500%.

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