adhesive sheet

Abstract

Provided is an adhesive sheet that has excellent adherend visibility (visibility through the adhesive sheet) and that has excellent adhesiveness and detachability.　The adhesive sheet according to the present invention is provided with a gas generation layer that generates a gas when being irradiated with laser light, and has a haze value of 50% or less. In one embodiment, the thickness of the gas generation layer is 0.1-50 µm. In one embodiment, the gas generation layer is a layer capable of absorbing ultraviolet rays. In one embodiment, the gas generation layer contains an ultraviolet absorber.

Description

[Technical Field]

[0001] The present invention relates to a pressure-sensitive adhesive sheet. [Background technology]

[0002] Conventionally, when processing (processing) electronic components, a process is sometimes performed in which the object to be processed is temporarily fixed to a fixing table via an adhesive sheet during processing, and then the object is peeled off from the adhesive sheet after processing. The adhesive sheets used in such processes are sometimes adhesive sheets that have a predetermined adhesive strength during processing but whose adhesive strength can decrease after processing. One such adhesive sheet has been proposed, which is an adhesive sheet containing heat-expandable microspheres in the adhesive layer (see, for example, Patent Document 1). An adhesive sheet containing heat-expandable microspheres has a characteristic that, while it has a predetermined adhesive strength, when heated, the heat-expandable microspheres expand, forming unevenness on the adhesive surface and reducing the contact area, thereby reducing or eliminating the adhesive strength. Such an adhesive sheet has the advantage that the object to be processed can be easily peeled off without external stress.

[0003] However, adhesive sheets containing heat-expandable microspheres have low light transmittance, and when such adhesive sheets are used, there is a problem in that it is difficult to see through the adhesive sheet markings on the fixing base to indicate the temporary fixing positions of electronic components. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Laid-Open No. 2001-131507 Summary of the Invention [Problem to be solved by the invention]

[0005] The present invention has been made to solve the above-mentioned conventional problems, and its object is to provide a pressure-sensitive adhesive sheet that combines excellent adhesion and releasability, and also has excellent visibility of the adherend (visibility through the pressure-sensitive adhesive sheet). [Means for solving the problem]

[0006] The pressure-sensitive adhesive sheet of the present invention includes a gas generating layer that generates gas when irradiated with laser light, and has a haze value of 50% or less. In one embodiment, the gas generating layer has a thickness of 0.1 μm to 50 μm. In one embodiment, the gas generating layer is a layer capable of absorbing ultraviolet light. In one embodiment, the gas generating layer includes an ultraviolet absorber. In one embodiment, the pressure-sensitive adhesive sheet has an ultraviolet transmittance of 30% or less at a wavelength of 360 nm. In one embodiment, the pressure-sensitive adhesive sheet has a transmittance of 50% to 100% for ultraviolet light with a wavelength of 500 nm. In one embodiment, the gas generating layer is a layer that generates a hydrocarbon gas. In one embodiment, the gasification initiation temperature of the gas generating layer is 150°C to 500°C. In one embodiment, the pressure-sensitive adhesive sheet has a 10% weight loss temperature of 200°C to 500°C. In one embodiment, the pressure-sensitive adhesive sheet further comprises a pressure-sensitive adhesive layer on at least one side of the gas-generating layer, the pressure-sensitive adhesive layer being a layer whose surface is deformed when the pressure-sensitive adhesive sheet is irradiated with laser light. In one embodiment, the pressure-sensitive adhesive layer has a thickness of 0.1 μm to 50 μm. In one embodiment, the pressure-sensitive adhesive layer is foamed by irradiating the pressure-sensitive adhesive sheet with laser light. According to another aspect of the present invention, there is provided a method for treating electronic components, which comprises adhering an electronic component to the pressure-sensitive adhesive sheet described above, and irradiating the pressure-sensitive adhesive sheet with laser light to peel the electronic component from the pressure-sensitive adhesive sheet. In one embodiment, the electronic component is peeled off in a position-selective manner. In one embodiment, the treatment method includes performing a predetermined treatment on the electronic component after the electronic component is attached to the pressure-sensitive adhesive sheet and before the electronic component is peeled off from the pressure-sensitive adhesive sheet. In one embodiment, the treatment is grinding, dicing, die bonding, wire bonding, etching, deposition, molding, circuit formation, inspection, testing, cleaning, transfer, alignment, repair, or protection of a device surface. According to another aspect of the present invention, there is provided a method for treating an electronic component, comprising peeling the electronic component from the pressure-sensitive adhesive sheet and then placing the electronic component on another sheet. [Effects of the Invention]

[0007] According to the present invention, it is possible to provide a pressure-sensitive adhesive sheet that combines excellent adhesiveness and releasability, and also has excellent adherend visibility (visibility through the pressure-sensitive adhesive sheet). [Brief explanation of the drawings]

[0008] [Figure 1] 1 is a schematic cross-sectional view of a pressure-sensitive adhesive sheet according to one embodiment of the present invention. [Figure 2] FIG. 2 is a schematic cross-sectional view of a pressure-sensitive adhesive sheet according to another embodiment of the present invention. [Figure 3] FIG. 2 is a schematic diagram illustrating a method for measuring puncture strength. DETAILED DESCRIPTION OF THE INVENTION

[0009] A. Overview of adhesive sheets Fig. 1(a) is a schematic cross-sectional view of a pressure-sensitive adhesive sheet according to one embodiment of the present invention. The pressure-sensitive adhesive sheet 100 includes a gas-generating layer 10. The gas-generating layer 10 generates gas when irradiated with laser light. More specifically, the gas-generating layer 10 is a layer that generates gas by gasifying its components when irradiated with laser light. UV laser light is typically used as the laser light. The gas-generating layer 10 can have a predetermined adhesive strength.

[0010] 1(b) is a schematic cross-sectional view of a pressure-sensitive adhesive sheet according to another embodiment of the present invention. The pressure-sensitive adhesive sheet 100' comprises a gas-generating layer 10 and at least one pressure-sensitive adhesive layer 20 disposed on one side of the gas-generating layer 10. The surface of the pressure-sensitive adhesive layer 20 can be deformed by irradiating the pressure-sensitive adhesive sheet (essentially the gas-generating layer) with laser light. In one embodiment, the deformation is caused by gas generated from the gas-generating layer 10 and can occur on the side of the pressure-sensitive adhesive layer 20 opposite the gas-generating layer 10.

[0011] The pressure-sensitive adhesive sheet of the present invention can be used by adhering a target object, such as an electronic component, to the gas-generating layer or adhesive layer. The pressure-sensitive adhesive sheet of the present invention includes a gas-generating layer and generates gas locally within a small area upon irradiation with laser light. Such gas generation causes deformation of the adhesion surface, resulting in satisfactory peeling of the adherend. When the pressure-sensitive adhesive sheet includes an adhesive layer, as described above, the gas generation causes deformation of the adhesive layer, resulting in the development of releasability in the area irradiated with laser light. Typically, the laser light is irradiated from the gas-generating layer opposite the adhesive layer. According to the present invention, deformation can be caused within a small area as described above, thereby enabling satisfactory peeling of even extremely fine small electronic components when processing (processing) them. Furthermore, even when small electronic components that require peeling and small electronic components that do not require peeling are temporarily fixed adjacent to each other, peeling occurs at the areas to be peeled and not at the areas not to be peeled, i.e., only the small electronic components that require peeling can be peeled, preventing unwanted detachment of the small electronic components. In order to allow the pressure-sensitive adhesive layer to deform satisfactorily, it is preferable that at least a portion of the generated gas is prevented from escaping from the pressure-sensitive adhesive sheet, and the pressure-sensitive adhesive layer can function as a gas barrier layer.

[0012] Deformation of the adhesive layer refers to displacements occurring in the normal direction (thickness direction) and horizontal direction (direction perpendicular to the thickness direction) of the adhesive layer. Deformation of the adhesive layer can be achieved, for example, by pulse scanning a UV laser beam with a wavelength of 355 nm and a beam diameter of approximately 20 μmφ at a power of 0.80 mW and a frequency of 40 kHz to generate gas from the gas-generating layer. The shape of the deformed layer can be observed, for example, by measuring an arbitrary pulse-scanned spot 24 hours after laser irradiation using a confocal laser microscope or a non-contact interference microscope (WYKO). The shape can be bubbles (convex), through-holes (irregularities), or depressions (concave), and these deformations can cause peelability. For efficient peeling of electronic components in the normal direction, a large change in normal displacement before and after laser irradiation is preferred, and a bubble-like shape is particularly suitable. The bubbles (convexities) are defined as the highest point, measured as the vertical displacement Y, and the full width at half maximum, measured as the horizontal displacement X (diameter), relative to the unirradiated surface of the adhesive sheet. For the through-holes (convex and concave) and depressions (concave) that form holes after laser light irradiation, the difference between the highest point and the lowest point is defined as the vertical displacement Y, and the diameter of the hole is defined as the horizontal displacement X. Hereinafter, the part that has been deformed by laser light irradiation will also be referred to as the "deformed part."

[0013] Fig. 2 is a schematic cross-sectional view of a pressure-sensitive adhesive sheet according to another embodiment of the present invention. Pressure-sensitive adhesive sheet 200 further comprises an intermediate layer 30 between gas-generating layer 10 and pressure-sensitive adhesive layer 20. By providing the intermediate layer, it becomes possible to easily control the deformation of the pressure-sensitive adhesive layer (details will be described later). The intermediate layer can also function as a gas barrier layer in cooperation with the pressure-sensitive adhesive layer. Therefore, by providing the intermediate layer, the gas barrier properties are improved, and a pressure-sensitive adhesive sheet in which the pressure-sensitive adhesive layer is deformed more favorably can be obtained. The intermediate layer may be a single layer or multiple layers.

[0014] Although not shown, the pressure-sensitive adhesive sheet may further include other layers. For example, a substrate, another pressure-sensitive adhesive layer, etc. may be provided on the surface of the gas-generating layer opposite the pressure-sensitive adhesive layer. As the substrate, for example, a film formed from any appropriate resin is used.

[0015] The pressure-sensitive adhesive sheet of the present invention is characterized by having a haze value of 50% or less. In the present invention, the gas-generating layer, pressure-sensitive adhesive layer, and intermediate layer can be formed without incorporating an insoluble filler or the like, thereby enabling the production of a pressure-sensitive adhesive sheet with a low haze value, high light transmittance, and reduced cloudiness. The pressure-sensitive adhesive sheet has high transparency before laser irradiation (at the time of temporary fixation). Use of such a pressure-sensitive adhesive sheet makes it possible, for example, to view an adherend (e.g., a stand for temporarily fixing electronic components) through the pressure-sensitive adhesive sheet, and, for example, to favorably view markings on the fixing stand to indicate the temporary fixation position of the electronic components through the pressure-sensitive adhesive sheet. This is an excellent effect that cannot be obtained with pressure-sensitive adhesive sheets containing insoluble fillers (e.g., pressure-sensitive adhesive sheets containing heat-expandable microspheres in the pressure-sensitive adhesive layer as a peelable layer).

[0016] The haze value of the pressure-sensitive adhesive sheet of the present invention is preferably 0% to 50%, more preferably 0.01% to 40%, even more preferably 0.05% to 30%, and particularly preferably 0.1% to 20%. Within these ranges, the above-mentioned effects of the present invention become more pronounced.

[0017] The adhesive strength of the adhesive layer of the pressure-sensitive adhesive sheet of the present invention to SUS430 is preferably 0.1 N / 20 mm or more, more preferably 0.2 to 50 N / 20 mm, even more preferably 0.5 to 40 N / 20 mm, particularly preferably 0.7 to 20 N / 20 mm, and most preferably 1 to 10 N / 20 mm. Within these ranges, a pressure-sensitive adhesive sheet exhibiting good adhesive properties can be obtained, for example, as a temporary fixing sheet used in the manufacture of electronic components. In this specification, the adhesive strength refers to the adhesive strength measured at 23°C using a method conforming to JIS Z 0237:2000 (lamination conditions: one reciprocating motion with a 2 kg roller, a pulling speed: 300 mm / min, and a peel angle of 180°).

[0018] In one embodiment, the gas generating layer has a predetermined adhesive strength. The adhesive strength of the gas generating layer of the pressure-sensitive adhesive sheet of the present invention to SUS430 is preferably 0.1 N / 20 mm or more, more preferably 0.5 N / 20 mm to 50 N / 20 mm, even more preferably 1 N / 20 mm to 40 N / 20 mm, particularly preferably 1.5 N / 20 mm to 30 N / 20 mm, and most preferably 2 N / 20 mm to 20 N / 20 mm. Within such a range, a pressure-sensitive adhesive sheet exhibiting good adhesiveness can be obtained, for example, as a temporary fixing sheet used in the production of electronic components.

[0019] The thickness of the pressure-sensitive adhesive sheet of the present invention is preferably 2 μm to 200 μm, more preferably 3 μm to 150 μm, and even more preferably 5 μm to 120 μm.

[0020] The water vapor permeability of the pressure-sensitive adhesive sheet of the present invention is preferably 5000 g / (m 2 ·day) or less, and more preferably 4800g / (m 2 ·day) or less, and more preferably 4500g / (m 2 ·day) or less, and more preferably 4200 g / (m 2 ·day) or less. In a pressure-sensitive adhesive sheet provided with a pressure-sensitive adhesive layer (and an intermediate layer, if necessary) having a water vapor transmission rate in this range, the escape of gas generated by laser light irradiation is prevented, and a deformed portion with an excellent shape is formed in the pressure-sensitive adhesive layer. By using such a pressure-sensitive adhesive sheet, it is possible to peel off small adherends (e.g., electronic components) with high precision. The lower the water vapor transmission rate of the pressure-sensitive adhesive sheet of the present invention, the better, but the lower limit thereof is, for example, 0.1 g / (m 2 The water vapor transmission rate can be measured in an atmosphere of 30°C and 90% RH by a measurement method in accordance with JIS K7129B.

[0021] The water vapor permeability of the laminate comprising the pressure-sensitive adhesive layer and the intermediate layer is preferably 10,000 g / (m 2 ·day) or less, and more preferably 7000g / (m 2·day) or less, and more preferably 5000g / (m 2 ·day) or less, and more preferably 4800g / (m 2 ·day) or less, and particularly preferably 4500g / (m 2 ·day) or less, and most preferably 4200g / (m 2 ·day) or less. Within this range, the laminate comprising the pressure-sensitive adhesive layer and the intermediate layer functions well as a gas barrier layer, and a deformed portion with an excellent shape is formed in the pressure-sensitive adhesive layer. By using such a pressure-sensitive adhesive sheet, it is possible to peel off a small adherend (for example, electronic components) with good precision. The lower the water vapor transmission rate of the laminate comprising the pressure-sensitive adhesive layer and the intermediate layer, the better, but the lower limit thereof is, for example, 1 g / (m 2 ·day).

[0022] The puncture strength of the laminate comprising the pressure-sensitive adhesive layer and intermediate layer is preferably 10 mN to 5,000 mN, more preferably 30 mN to 4,000 mN, even more preferably 50 mN to 3,000 mN, and particularly preferably 100 mN to 2,000 mN. Within these ranges, the laminate comprising the pressure-sensitive adhesive layer and intermediate layer functions well as a gas barrier layer, and deforms due to gas generation favorably, resulting in the formation of a deformed portion with an excellent shape in the pressure-sensitive adhesive layer. Use of such a pressure-sensitive adhesive sheet enables accurate peeling of small adherends (e.g., electronic components). As shown in FIG. 3, the puncture strength is measured using a compression tester 6 (manufactured by Kato Tech Co., Ltd., product name "KES-G5") by clamping a sample 4 (e.g., a laminate) between sample holders 5A and 5B having a circular opening with a diameter of 11.28 mm. More specifically, at a measurement temperature of 23°C, a piercing needle (curvature radius: 1 mm) is pierced into the sample at the center of the circular opening (piercing speed: 0.1 mm / s), and the maximum load at the breaking point can be taken as the piercing strength.

[0023] The transmittance of ultraviolet light at a wavelength of 360 nm of the laminate comprising the pressure-sensitive adhesive layer and the intermediate layer is preferably 50% to 100%, and more preferably 60% to 95%.

[0024] The transmittance of the pressure-sensitive adhesive sheet to ultraviolet light at a wavelength of 360 nm is preferably 30% or less, more preferably 20% or less, even more preferably 15% or less, particularly preferably 10% or less, and most preferably 5% or less. The lower limit of the transmittance of the pressure-sensitive adhesive sheet to ultraviolet light at a wavelength of 360 nm is, for example, 0% (preferably 0.05%, more preferably 0.1%).

[0025] The transmittance of the pressure-sensitive adhesive sheet at an ultraviolet ray wavelength of 500 nm is preferably 50% to 100%, more preferably 60% to 99%, even more preferably 70% to 98%, and particularly preferably 80% to 97%.

[0026] The 10% weight loss temperature of the pressure-sensitive adhesive sheet is preferably 200°C to 500°C, more preferably 220°C to 450°C, even more preferably 250°C to 400°C, and particularly preferably 270°C to 370°C. Within these ranges, a pressure-sensitive adhesive sheet capable of forming a better deformed portion upon laser light irradiation can be obtained. The 10% weight loss temperature of the pressure-sensitive adhesive sheet refers to the temperature at which, in TGA analysis when the pressure-sensitive adhesive sheet is heated, the weight has decreased by 10% by weight compared to the weight before heating (i.e., the weight of the pressure-sensitive adhesive sheet has reached 90% of the weight before irradiation).

[0027] B. Gas generation layer The gas-generating layer may be a layer capable of absorbing ultraviolet light. In one embodiment, the gas-generating layer contains an ultraviolet absorber. By including an ultraviolet absorber, it is possible to form a gas-generating layer that can absorb laser light and gasify. Typically, the gas-generating layer contains an ultraviolet absorber and a pressure-sensitive adhesive A. Preferably, the ultraviolet absorber is present in a state of being dissolved in the pressure-sensitive adhesive A. If the ultraviolet absorber is present in a state of being dissolved in the pressure-sensitive adhesive A, it is possible to generate deformed portions (e.g., uneven portions) at any location on the adhesion surface (the gas-generating layer surface and / or the pressure-sensitive adhesive layer surface), and it is possible to obtain a pressure-sensitive adhesive sheet with little variation in the shape of the deformed portions (e.g., uneven portions). Use of such a pressure-sensitive adhesive sheet allows deformed portions (e.g., uneven portions) to be generated with precision at desired locations, thereby achieving remarkable effects of the present invention. In this specification, the state of being "present in a state of being dissolved in the pressure-sensitive adhesive" means that the ultraviolet absorber is not present as particles in the gas-generating layer. More specifically, the gas generating layer preferably does not contain an ultraviolet absorber with a particle size of 10 μm or more when particle distribution in the cross section of the gas generating layer is measured by X-ray CT. The gas generating layer may or may not contain a component that is insoluble in the adhesive. In one embodiment, the presence or absence of an insoluble component in the gas generating layer and its content are evaluated based on the haze value of the gas generating layer, and the smaller the haze value, the lower the content of the insoluble component in the gas generating layer. Preferably, the gas generating layer is substantially free of a component that is insoluble in the adhesive.

[0028] The elastic modulus of the cross section of the gas generating layer measured by nanoindentation is preferably 0.01 MPa to 1000 MPa, and more preferably 0.05 MPa to 800 MPa. Within this range, the gas generating layer deforms favorably due to gas generation, resulting in the formation of a deformed portion with an excellent shape on the adhesion surface (the surface of the gas generating layer and / or the surface of the pressure-sensitive adhesive layer). The elastic modulus measured by nanoindentation refers to the elastic modulus determined by continuously measuring the load and indentation depth applied to the indenter when the indenter is pressed into the sample (e.g., the adhesive surface) during loading and unloading, and then obtaining a load-indentation depth curve. The elastic modulus measured by nanoindentation is determined by pressing a diamond Berkovich-type (triangular pyramidal) probe perpendicularly against a cut-out cross section of the layer to be measured, and then numerically processing the resulting displacement-load hysteresis curve using software (triboscan) provided with the measurement device. As used herein, the term "elastic modulus measured by nanoindentation of a cross section" refers to the elastic modulus measured by a single indentation method at a predetermined temperature (25°C) using a nanoindenter (Triboindenter TI-950 manufactured by Hysitron Inc.) under the following measurement conditions: an indentation speed of approximately 500 nm / sec, an extraction speed of approximately 500 nm / sec, and an indentation depth of approximately 1500 nm. The elastic modulus of the gas-generating layer can be adjusted by the type of material contained in the layer, the structure of the base polymer constituting the material, the type and amount of additives added to the layer, etc. As used herein, when the term "elastic modulus measured by nanoindentation" is used without reference to a cross section or surface, the term refers to the elastic modulus measured by nanoindentation of a cross section.

[0029] The elastic modulus of the surface of the gas generating layer measured by nanoindentation is preferably 0.01 MPa to 1000 MPa, and more preferably 0.05 MPa to 800 MPa. Within this range, the gas generating layer preferably changes shape due to gas generation, resulting in the formation of a deformed portion with an excellent shape in the pressure-sensitive adhesive layer. The elastic modulus measured by nanoindentation refers to the elastic modulus determined by continuously measuring the load and indentation depth applied to an indenter when the indenter is pressed into a sample (e.g., the adhesive surface) during loading and unloading, and then obtaining a load-indentation depth curve. The elastic modulus measured by nanoindentation is determined by pressing a diamond Berkovich-type (triangular pyramidal) probe perpendicularly against a cut-out cross section of the layer to be measured, and then numerically processing the resulting displacement-load hysteresis curve using software (triboscan) provided with the measurement device. As used herein, the elastic modulus measured by nanoindentation of a surface refers to the elastic modulus measured using a nanoindenter (Triboindenter TI-950 manufactured by Hysitron Inc.) by a single indentation method at a predetermined temperature (25°C) under measurement conditions of an indentation speed of approximately 500 nm / sec, an extraction speed of approximately 500 nm / sec, and an indentation depth of approximately 3000 nm. The elastic modulus of the gas-generating layer can be adjusted by the type of material contained in the layer, the structure of the base polymer constituting the material, the type and amount of additives added to the layer, etc. In the present invention, there is no significant difference between the elastic modulus measured by nanoindentation using a cross-section as the measurement surface and the elastic modulus measured by nanoindentation using a surface as the measurement surface. Therefore, when it is difficult to measure from a cross-section, the value measured from the surface can be used as the value measured from the cross-section.

[0030] The gasification initiation temperature of the gas generating layer is preferably 150°C to 500°C, more preferably 170°C to 450°C, even more preferably 190°C to 420°C, and particularly preferably 200°C to 400°C. Within these ranges, a pressure-sensitive adhesive sheet capable of forming a better deformed portion upon laser light irradiation can be obtained. In this specification, the gasification initiation temperature of the gas generating layer refers to the gas generation onset temperature calculated from EGA analysis when the pressure-sensitive adhesive sheet is heated. The gas generation onset temperature is defined as the temperature at which the maximum gas generation peak in the EGA / MS spectrum obtained from the EGA analysis reaches half its maximum. The lower the gasification initiation temperature, the lower the temperature at which gas begins to be generated upon laser light irradiation, and a sufficient amount of gas is generated even when the laser light is irradiated at a lower power. In one embodiment, the gasification initiation temperature of the gas generating layer corresponds to the gasification initiation temperature of the ultraviolet absorber.

[0031] The 10% weight loss temperature of the gas generating layer is preferably 150°C to 500°C, more preferably 170°C to 450°C, and even more preferably 200°C to 400°C. Within these ranges, a pressure-sensitive adhesive sheet capable of forming a better deformed portion upon laser light irradiation can be obtained. The 10% weight loss temperature of the gas generating layer refers to the temperature at which, in a TGA analysis performed upon heating the pressure-sensitive adhesive sheet (for example, upon heating by laser light irradiation), the weight of the gas generating layer has decreased by 10% by weight relative to the weight before heating (i.e., the weight of the gas generating layer has become 90% of the weight before heating).

[0032] The thickness of the gas generating layer is preferably 0.1 μm to 50 μm, more preferably 1 μm to 40 μm, even more preferably 2 μm to 30 μm, and particularly preferably 5 μm to 20 μm. Within these ranges, a pressure-sensitive adhesive sheet capable of forming a better deformed portion upon irradiation with laser light can be obtained.

[0033] The gas generating layer has an elastic modulus Er (gas) [unit: MPa] and a thickness h (gas) [unit: μm] measured by nanoindentation, which satisfy the following formula (1). Log(Er(gas)×10 6 )≧8.01×h(gas) -0.116 ···(1) In the present invention, the gas generating layer is configured to satisfy the above formula (1), thereby preventing excessive deformation due to the gas generated from the gas generating layer, and the pressure-sensitive adhesive sheet deforms well when irradiated with laser light. By forming such a gas generating layer, it is possible to generate surface deformation in a small area without providing a thick barrier layer (pressure-sensitive adhesive layer) as a layer to prevent excessive deformation. More specifically, the gas generating layer alone can cause surface deformation, or the pressure-sensitive adhesive layer (gas barrier layer) can be configured to be flexible.

[0034] In one embodiment, the elastic modulus Er(gas) [unit: MPa] and thickness h(gas) [unit: μm] measured by nanoindentation satisfy the following formula (2): In one embodiment, the elastic modulus Er(gas) [unit: MPa] and thickness h(gas) [unit: μm] measured by nanoindentation satisfy the following formula (3): Log(Er(gas)×10 6 )≧7.66×h(gas) -0.092 ···(2) Log(Er(gas)×10 6 )≧7.52×h(gas) -0.081 ···(3) Within this range, the above effects become more pronounced.

[0035] In one embodiment, the elastic modulus Er (gas) [unit: MPa] measured by nanoindentation and the thickness h (gas) [unit: μm] further satisfy the following formula (4). Log(Er(gas)×10 6 )≦47.675×h(gas) -0.519 ···(4)

[0036] The transmittance of the gas generating layer for ultraviolet light at a wavelength of 360 nm is preferably 30% or less, more preferably 20% or less, even more preferably 15% or less, particularly preferably 10% or less, and most preferably 5% or less. The lower limit of the transmittance of ultraviolet light at a wavelength of 360 nm for the gas generating layer is, for example, 0% (preferably 0.05%, more preferably 0.1%).

[0037] The haze value of the gas-generating layer is preferably 55% or less, more preferably 0.1% to 50%, and even more preferably 0.5% to 40%. The haze value serves as an indicator of the compatibility between the pressure-sensitive adhesive (substantially the base polymer) and the UV absorber in the gas-generating layer. The haze value is determined from the ratio of diffuse transmitted light to total transmitted light when light in the visible light range (wavelength: 380 nm to 780 nm) is incident. Considering the wavelength of light as the smallest unit, if the concentration and composition are uniform at or above the wavelength, transparency is high, i.e., compatibility is high. On the other hand, if the concentration and composition are non-uniform, light scattering occurs, resulting in cloudiness, i.e., compatibility is low. If the haze of the gas-generating layer is within the above range, the UV absorber can be distributed evenly in the pressure-sensitive adhesive sheet. Such a pressure-sensitive adhesive sheet exhibits accurate releasability when irradiated with laser light.

[0038] B-1. UV absorbers Any appropriate ultraviolet absorber may be used as the ultraviolet absorber as long as the effects of the present invention can be obtained. Examples of ultraviolet absorbers include benzophenone-based ultraviolet absorbers, triazine-based ultraviolet absorbers, salicylate-based ultraviolet absorbers, and cyanoacrylate-based ultraviolet absorbers. Among these, triazine-based ultraviolet absorbers are preferred. In particular, when an acrylic adhesive is used as the adhesive A, triazine-based ultraviolet absorbers are preferably used because of their high compatibility with the base polymer of the acrylic adhesive. By using a triazine-based ultraviolet absorber, a gas generating layer with a low haze value can be formed. The triazine-based ultraviolet absorber is more preferably composed of a compound having a hydroxyl group, and an ultraviolet absorber composed of a hydroxyphenyltriazine-based compound (hydroxyphenyltriazine-based ultraviolet absorber) is particularly preferred.

[0039] Examples of hydroxyphenyltriazine-based ultraviolet absorbers include a reaction product of 2-(4,6-bis(2,4-dimethylphenyl)-1,3,5-triazin-2-yl)-5-hydroxyphenyl with [(C10-C16 (mainly C12-C13) alkyloxy)methyl]oxirane (trade name "TINUVIN 400", manufactured by BASF), 2-[4,6-bis(2,4-dimethylphenyl)-1,3,5-triazin-2-yl]-5-[3-(dodecyloxy)-2-hydroxypropoxy]phenol, and a reaction product of 2-(2,4-dihydroxyphenyl)-4,6-bis-(2,4-dimethylphenyl)-1,3,5-triazine with (2-ethylhexyl)glycidic acid ester (trade name "TINUVIN 405, manufactured by BASF), 2,4-bis(2-hydroxy-4-butoxyphenyl)-6-(2,4-dibutoxyphenyl)-1,3,5-triazine (trade name "TINUVIN 460", manufactured by BASF), 2-(4,6-diphenyl-1,3,5-triazin-2-yl)-5-[(hexyl)oxy]-phenol (trade name "TINUVIN 1577", manufactured by BASF), 2-(4,6-diphenyl-1,3,5-triazin-2-yl)-5-[2-(2-ethylhexanoyloxy)ethoxy]-phenol (trade name "ADEKA STAB LA-46", manufactured by ADEKA Corporation), 2-(2-hydroxy-4-[1-octyloxycarbonylethoxy]phenyl)-4,6-bis(4-phenylphenyl)-1,3,5-triazine (trade name "TINUVIN BASF's trade name "TINUVIN 477" and the like.

[0040] Examples of benzotriazole-based ultraviolet absorbers (benzotriazole-based compounds) include 2-(2-hydroxy-5-tert-butylphenyl)-2H-benzotriazole (trade name "TINUVIN PS", manufactured by BASF), an ester compound of benzenepropanoic acid and 3-(2H-benzotriazol-2-yl)-5-(1,1-dimethylethyl)-4-hydroxy (C7-9 side chain and linear alkyl) (trade name "TINUVIN 384-2", manufactured by BASF), a mixture of octyl 3-[3-tert-butyl-4-hydroxy-5-(5-chloro-2H-benzotriazol-2-yl)phenyl]propionate and 2-ethylhexyl-3-[3-tert-butyl-4-hydroxy-5-(5-chloro-2H-benzotriazol-2-yl)phenyl]propionate (trade name "TINUVIN 109, manufactured by BASF), 2-(2H-benzotriazol-2-yl)-4,6-bis(1-methyl-1-phenylethyl)phenol (trade name "TINUVIN 900", manufactured by BASF), 2-(2H-benzotriazol-2-yl)-6-(1-methyl-1-phenylethyl)-4-(1,1,3,3-tetramethylbutyl)phenol (trade name "TINUVIN 928", manufactured by BASF), reaction products of methyl 3-(3-(2H-benzotriazol-2-yl)-5-tert-butyl-4-hydroxyphenyl)propionate / polyethylene glycol 300 (trade name "TINUVIN 1130", manufactured by BASF), 2-(2H-benzotriazol-2-yl)-p-cresol (trade name "TINUVIN P", manufactured by BASF), 2-(2H-benzotriazol-2-yl)-4,6-bis(1-methyl-1-phenylethyl)phenol (trade name "TINUVIN 234", manufactured by BASF), 2-[5-chloro-2H-benzotriazol-2-yl]-4-methyl-6-(tert-butyl)phenol (trade name "TINUVIN 326", manufactured by BASF), 2-(2H-benzotriazol-2-yl)-4,6-di-tert-pentylphenol (trade name "TINUVIN 328", manufactured by BASF), 2-(2H-benzotriazol-2-yl)-4-(1,1,3,3-tetramethylbutyl)phenol (trade name "TINUVIN 329", manufactured by BASF), 2,2'-methylenebis[6-(2H-benzotriazol-2-yl)-4-(1,1,3,3-tetramethylbutyl)phenol] (trade name "TINUVIN 360", manufactured by BASF), reaction products of methyl 3-(3-(2H-benzotriazol-2-yl)-5-tert-butyl-4-hydroxyphenyl)propionate with polyethylene glycol 300 (trade name "TINUVIN 213", manufactured by BASF), 2-(2H-benzotriazol-2-yl)-6-dodecyl-4-methylphenol (trade name "TINUVIN 571", manufactured by BASF), 2-[2-hydroxy-3-(3,4,5,6-tetrahydrophthalimido-methyl)-5-methylphenyl]benzotriazole (trade name "Sumisorb 250" manufactured by Sumitomo Chemical Co., Ltd.), 2-(3-tert-butyl-2-hydroxy-5-methylphenyl)-5-chloro-2H-benzotriazole (trade name "SEESORB 703" manufactured by Shipro Chemical Co., Ltd.), 2-(2H-benzotriazol-2-yl)-4-methyl-6-(3,4,5,6-tetrahydrophthalimidylmethyl)phenol (trade name "SEESORB 706" manufactured by Shipro Chemical Co., Ltd.), 2-(4-benzoyloxy-2-hydroxyphenyl)-5-chloro-2H-benzotriazole (trade name "SEESORB 7012BA" manufactured by Shipro Chemical Co., Ltd.), 2-tert-butyl-6-(5-chloro-2H-benzotriazol-2-yl)-4-methylphenol (trade name "KEMISORB 73" manufactured by Chemipro Chemical Co., Ltd.), 2,2'-methylenebis[6-(2H-benzotriazol-2-yl)-4-tert-octylphenol] (trade name "ADK STAB LA-31" manufactured by ADEKA Corporation), 2-(2H-benzotriazol-2-yl)-p-cellulose (trade name "ADK STAB LA-32" manufactured by ADEKA Corporation), 2-(5-chloro-2H-benzotriazol-2-yl)-6-tert-butyl-4-methylphenol (trade name "ADK STAB LA-36" manufactured by ADEKA Corporation), etc.

[0041] In one embodiment, an ultraviolet absorber that does not contain halogen atoms is used. By using such an ultraviolet absorber, a pressure-sensitive adhesive sheet that is less likely to contaminate adherends such as electrodes can be obtained.

[0042] The molecular weight of the compound constituting the ultraviolet absorber is preferably 200 to 1500, more preferably 250 to 1200, and even more preferably 300 to 1000. Within such a range, a pressure-sensitive adhesive sheet capable of forming a better deformed portion upon irradiation with laser light can be obtained.

[0043] The maximum absorption wavelength of the ultraviolet absorber is preferably 300 nm to 450 nm, more preferably 320 nm to 400 nm, and even more preferably 330 nm to 380 nm.

[0044] The content of the ultraviolet absorber is preferably 1 to 100 parts by weight, more preferably 1 to 50 parts by weight, and even more preferably 5 to 30 parts by weight, relative to 100 parts by weight of the gas generating layer. Within such a range, a pressure-sensitive adhesive sheet capable of forming a better deformed portion upon irradiation with laser light can be obtained.

[0045] B-2. Adhesive A As the adhesive A contained in the gas generating layer, a pressure-sensitive adhesive A is preferably used. Examples of the adhesive A include acrylic adhesives, rubber adhesives, vinyl alkyl ether adhesives, silicone adhesives, polyester adhesives, polyamide adhesives, urethane adhesives, and styrene-diene block copolymer adhesives. Among these, acrylic adhesives or rubber adhesives are preferred, and acrylic adhesives are more preferred. The above adhesives may be used alone or in combination of two or more.

[0046] Examples of the acrylic adhesive include an acrylic adhesive having as a base polymer an acrylic polymer (homopolymer or copolymer) using one or more (meth)acrylic acid alkyl esters as a monomer component. Specific examples of the (meth)acrylic acid alkyl ester include methyl (meth)acrylate, ethyl (meth)acrylate, propyl (meth)acrylate, isopropyl (meth)acrylate, butyl (meth)acrylate, isobutyl (meth)acrylate, s-butyl (meth)acrylate, t-butyl (meth)acrylate, pentyl (meth)acrylate, hexyl (meth)acrylate, heptyl (meth)acrylate, octyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, isooctyl (meth)acrylate, and methyl (meth)acrylate. Examples of (meth)acrylic acid C1-20 alkyl esters include nonyl acrylate, isononyl (meth)acrylate, decyl (meth)acrylate, isodecyl (meth)acrylate, undecyl (meth)acrylate, dodecyl (meth)acrylate, tridecyl (meth)acrylate, tetradecyl (meth)acrylate, pentadecyl (meth)acrylate, hexadecyl (meth)acrylate, heptadecyl (meth)acrylate, octadecyl (meth)acrylate, nonadecyl (meth)acrylate, and eicosyl (meth)acrylate. Among these, (meth)acrylic acid C1-20 alkyl esters having a linear or branched alkyl group with 1 to 20 carbon atoms can be preferably used, and (meth)acrylic acid C1-20 alkyl esters having a linear or branched alkyl group with 2 to 20 carbon atoms can be more preferably used.

[0047] In one embodiment, a (meth)acrylic acid alkyl ester A having a linear or branched alkyl group having 4 or more carbon atoms (preferably 4 to 20, more preferably 4 to 18) is used. Acrylic polymers formed using such monomers and having long side chains are advantageous in that they have high affinity (compatibility) with UV absorbers. The content of the (meth)acrylic acid alkyl ester A is preferably 30% by weight or more, more preferably 50% by weight or more, even more preferably 70% by weight to 100% by weight, and particularly preferably 80% by weight to 100% by weight, based on all structural units constituting the acrylic polymer. Within such a range, the compatibility between the acrylic polymer and the UV absorber can be improved. The content of the acrylic polymer containing structural units derived from the (meth)acrylic acid alkyl ester A is preferably 30 parts by weight to 100 parts by weight, more preferably 70 parts by weight to 100 parts by weight, based on 100 parts by weight of the total amount of the acrylic polymer.

[0048] In one embodiment, a (meth)acrylic acid alkyl ester A having a linear or branched alkyl group with 4 or more carbon atoms (preferably 4 to 20, more preferably 4 to 18) is used in combination with a triazine-based ultraviolet absorber. The (meth)acrylic acid alkyl ester A and the triazine-based ultraviolet absorber have particularly excellent compatibility, and a pressure-sensitive adhesive sheet having a gas-generating layer formed using these compounds has remarkably excellent visibility.

[0049] The acrylic polymer may contain, as necessary, units corresponding to other monomer components copolymerizable with the alkyl (meth)acrylate, for the purpose of modifying properties such as cohesive strength, heat resistance, and crosslinkability. Examples of such monomer components include carboxyl group-containing monomers such as acrylic acid, methacrylic acid, carboxyethyl acrylate, carboxypentyl acrylate, itaconic acid, maleic acid, fumaric acid, and crotonic acid; acid anhydride monomers such as maleic anhydride and itanoic anhydride; hydroxyl group-containing monomers such as hydroxyethyl (meth)acrylate, hydroxypropyl (meth)acrylate, hydroxybutyl (meth)acrylate, hydroxyhexyl (meth)acrylate, hydroxyoctyl (meth)acrylate, hydroxydecyl (meth)acrylate, hydroxylauryl (meth)acrylate, and (4-hydroxymethylcyclohexyl)methyl methacrylate; sulfonic acid group-containing monomers such as styrenesulfonic acid, allylsulfonic acid, 2-(meth)acrylamido-2-methylpropanesulfonic acid, (meth)acrylamidopropanesulfonic acid, sulfopropyl (meth)acrylate, and (meth)acryloyloxynaphthalenesulfonic acid; (N-substituted) amide monomers such as methylol (meth) acrylamide, N,N-dimethyl (meth) acrylamide, N-butyl (meth) acrylamide, N-methylol (meth) acrylamide, and N-methylol propane (meth) acrylamide; aminoalkyl (meth) acrylate monomers such as aminoethyl (meth) acrylate, N,N-dimethylaminoethyl (meth) acrylate, and t-butylaminoethyl (meth) acrylate; alkoxyalkyl (meth) acrylate monomers such as methoxyethyl (meth) acrylate and ethoxyethyl (meth) acrylate; maleimide monomers such as N-cyclohexyl maleimide, N-isopropyl maleimide, N-lauryl maleimide, and N-phenyl maleimide; itaconimide monomers such as N-methyl itaconimide, N-ethyl itaconimide, N-butyl itaconimide, N-octyl itaconimide, N-2-ethylhexyl itaconimide, N-cyclohexyl itaconimide, and N-lauryl itaconimide;succinimide-based monomers such as N-(meth)acryloyloxymethylene succinimide, N-(meth)acryloyl-6-oxyhexamethylene succinimide, and N-(meth)acryloyl-8-oxyoctamethylene succinimide; vinyl-based monomers such as vinyl acetate, vinyl propionate, N-vinylpyrrolidone, methylvinylpyrrolidone, vinylpyridine, vinylpiperidone, vinylpyrimidine, vinylpiperazine, vinylpyrazine, vinylpyrrole, vinylimidazole, vinyloxazole, vinylmorpholine, N-vinylcarboxylic acid amides, styrene, α-methylstyrene, and N-vinylcaprolactam; cyanoacrylate monomers such as acrylonitrile and methacrylonitrile; epoxy group-containing acrylic monomers such as glycidyl (meth)acrylate; polyethylene glycol (meth)acrylate, polypropylene glycol (meth)acrylate, methoxyethylene glycol (meth)acrylate, and (meth)acrylate. Examples of suitable monomers include glycol-based acrylic ester monomers such as methoxypolypropylene glycol acrylate; acrylic ester monomers having heterocycles, halogen atoms, silicon atoms, etc., such as tetrahydrofurfuryl (meth)acrylate, fluorine (meth)acrylate, and silicone (meth)acrylate; polyfunctional monomers such as hexanediol di(meth)acrylate, (poly)ethylene glycol di(meth)acrylate, (poly)propylene glycol di(meth)acrylate, neopentyl glycol di(meth)acrylate, pentaerythritol di(meth)acrylate, trimethylolpropane tri(meth)acrylate, pentaerythritol tri(meth)acrylate, dipentaerythritol hexa(meth)acrylate, epoxy acrylate, polyester acrylate, and urethane acrylate; olefin-based monomers such as isoprene, butadiene, and isobutylene; and vinyl ether-based monomers such as vinyl ether. These monomer components may be used alone or in combination of two or more. Among these, from the viewpoint of particularly high affinity (compatibility) with ultraviolet absorbers, carboxyl group-containing monomers such as acrylic acid, methacrylic acid, carboxyethyl acrylate, carboxypentyl acrylate, itaconic acid, maleic acid, fumaric acid, and crotonic acid;Acid anhydride monomers such as maleic anhydride and itanoic anhydride; and hydroxyl group-containing monomers such as hydroxyethyl (meth)acrylate, hydroxypropyl (meth)acrylate, hydroxybutyl (meth)acrylate, hydroxyhexyl (meth)acrylate, hydroxyoctyl (meth)acrylate, hydroxydecyl (meth)acrylate, hydroxylauryl (meth)acrylate, and (4-hydroxymethylcyclohexyl)methyl methacrylate are preferably used. The content of the carboxyl group-containing monomer is preferably 0.5 to 15 parts by weight, more preferably 1 to 10 parts by weight, and even more preferably 3 to 9.5 parts by weight, based on 100 parts by weight of the total amount of the acrylic polymer. The content of the acid anhydride monomer is preferably 0.5 to 15 parts by weight, more preferably 1 to 10 parts by weight, and even more preferably 3 to 9.5 parts by weight, based on 100 parts by weight of the total amount of the acrylic polymer. The content of the hydroxyl group-containing monomer is preferably 0.5 to 15 parts by weight, more preferably 1 to 10 parts by weight, and even more preferably 3 to 9.5 parts by weight, relative to 100 parts by weight of the total amount of the acrylic polymer.

[0050] Examples of the rubber-based pressure-sensitive adhesive include rubber-based pressure-sensitive adhesives whose base polymer is natural rubber; polyisoprene rubber, styrene-butadiene (SB) rubber, styrene-isoprene (SI) rubber, styrene-isoprene-styrene block copolymer (SIS) rubber, styrene-butadiene-styrene block copolymer (SBS) rubber, styrene-ethylene-butylene-styrene block copolymer (SEBS) rubber, styrene-ethylene-propylene-styrene block copolymer (SEPS) rubber, styrene-ethylene-propylene block copolymer (SEP) rubber, reclaimed rubber, butyl rubber, polyisobutylene, and synthetic rubbers such as modified versions of these.

[0051] The gas generated from the gas generating layer is preferably a hydrocarbon (preferably an aliphatic hydrocarbon) gas. A gas generating layer capable of generating a hydrocarbon gas is composed, for example, of a hydrocarbon compound as a main component. The gas generating layer preferably does not contain a compound containing a halogen element. If the generated gas is a hydrocarbon gas, corrosion of the electronic component, which is the workpiece, can be prevented. This effect becomes more pronounced by forming a gas generating layer that does not contain a compound containing a halogen element. The formula mass of ions generated from the gas generating layer is preferably 10 m / z to 800 m / z, more preferably 11 m / z to 700 m / z, even more preferably 12 m / z to 500 m / z, and particularly preferably 13 m / z to 400 m / z.

[0052] The PSA A may contain any suitable additives as needed, such as crosslinkers, tackifiers (e.g., rosin-based tackifiers, terpene-based tackifiers, hydrocarbon-based tackifiers, etc.), plasticizers (e.g., trimellitic ester-based plasticizers, pyromellitic ester-based plasticizers), pigments, dyes, antioxidants, conductive materials, antistatic agents, light stabilizers, release modifiers, softeners, surfactants, flame retardants, antioxidants, etc.

[0053] Examples of the crosslinking agent include isocyanate-based crosslinking agents, epoxy-based crosslinking agents, melamine-based crosslinking agents, peroxide-based crosslinking agents, as well as urea-based crosslinking agents, metal alkoxide-based crosslinking agents, metal chelate-based crosslinking agents, metal salt-based crosslinking agents, carbodiimide-based crosslinking agents, oxazoline-based crosslinking agents, aziridine-based crosslinking agents, and amine-based crosslinking agents. Of these, isocyanate-based crosslinking agents and epoxy-based crosslinking agents are preferred.

[0054] Specific examples of the isocyanate-based crosslinking agent include lower aliphatic polyisocyanates such as butylene diisocyanate and hexamethylene diisocyanate; alicyclic isocyanates such as cyclopentylene diisocyanate, cyclohexylene diisocyanate and isophorone diisocyanate; aromatic isocyanates such as 2,4-tolylene diisocyanate, 4,4'-diphenylmethane diisocyanate and xylylene diisocyanate; and isocyanate adducts such as trimethylolpropane / tolylene diisocyanate trimer adduct (manufactured by Nippon Polyurethane Industry Co., Ltd., trade name "Coronate L"), trimethylolpropane / hexamethylene diisocyanate trimer adduct (manufactured by Nippon Polyurethane Industry Co., Ltd., trade name "Coronate HL"), and isocyanurate of hexamethylene diisocyanate (manufactured by Nippon Polyurethane Industry Co., Ltd., trade name "Coronate HX"). The content of the isocyanate-based crosslinking agent can be set to any appropriate amount depending on the desired adhesive strength, and is typically 0.1 to 20 parts by weight, and more preferably 0.5 to 10 parts by weight, per 100 parts by weight of the base polymer.

[0055] Examples of the epoxy crosslinking agent include N,N,N',N'-tetraglycidyl-m-xylylenediamine, diglycidylaniline, 1,3-bis(N,N-glycidylaminomethyl)cyclohexane (manufactured by Mitsubishi Gas Chemical Company, Inc., trade name "Tetrad C"), 1,6-hexanediol diglycidyl ether (manufactured by Kyoeisha Chemical Co., Ltd., trade name "Epolight 1600"), neopentyl glycol diglycidyl ether (manufactured by Kyoeisha Chemical Co., Ltd., trade name "Epolight 1500NP"), ethylene glycol diglycidyl ether (manufactured by Kyoeisha Chemical Co., Ltd., trade name "Epolight 1500NP"), and ethylene glycol diglycidyl ether (manufactured by Kyoeisha Chemical Co., Ltd., trade name "Epolight 1500NP"). Licor diglycidyl ether (manufactured by Kyoeisha Chemical Co., Ltd., trade name "Epolight 40E"), propylene glycol diglycidyl ether (manufactured by Kyoeisha Chemical Co., Ltd., trade name "Epolight 70P"), polyethylene glycol diglycidyl ether (manufactured by NOF Corporation, trade name "Epiol E-400"), polypropylene glycol diglycidyl ether (manufactured by NOF Corporation, trade name "Epiol P-200"), sorbitol polyglycidyl ether (manufactured by Nagase ChemteX Corporation, trade name "Denacol") Examples of suitable crosslinking agents include glycerol polyglycidyl ether (manufactured by Nagase ChemteX Corporation under the trade name "Denacol EX-611"), glycerol polyglycidyl ether (manufactured by Nagase ChemteX Corporation under the trade name "Denacol EX-314"), pentaerythritol polyglycidyl ether, polyglycerol polyglycidyl ether (manufactured by Nagase ChemteX Corporation under the trade name "Denacol EX-512"), sorbitan polyglycidyl ether, trimethylolpropane polyglycidyl ether, adipic acid diglycidyl ester, o-phthalic acid diglycidyl ester, triglycidyl tris(2-hydroxyethyl)isocyanurate, resorcinol diglycidyl ether, bisphenol-S-diglycidyl ether, and epoxy resins having two or more epoxy groups in the molecule. The content of the epoxy crosslinking agent can be set at any appropriate amount depending on the desired adhesive strength, and is typically 0.01 to 10 parts by weight, and more preferably 0.03 to 5 parts by weight, per 100 parts by weight of the base polymer.

[0056] C.Adhesive layer The adhesive layer includes any appropriate adhesive B. The adhesive B may be a pressure-sensitive adhesive B1 or a curable adhesive B2.

[0057] The thickness of the pressure-sensitive adhesive layer is preferably 0.1 μm to 50 μm, more preferably 0.5 μm to 40 μm, even more preferably 1 μm to 30 μm, and particularly preferably 2 μm to 20 μm. Within this range, a pressure-sensitive adhesive layer having desirable adhesive strength and functioning well as a gas barrier layer can be formed.

[0058] The water vapor permeability of the pressure-sensitive adhesive layer is preferably 20,000 g / (m 2 ·day) or less, and more preferably 10,000g / (m 2 ·day) or less, and more preferably 7000g / (m 2 ·day) or less, and more preferably 5000g / (m 2 ·day) or less, and particularly preferably 4800g / (m 2 ·day) or less, and most preferably 4500g / (m 2 ·day) or less. Within this range, the pressure-sensitive adhesive layer functions well as a gas barrier layer, and a deformed portion with an excellent shape is formed. By using such a pressure-sensitive adhesive sheet, it is possible to peel off a small adherend (for example, electronic components) with high precision. The lower the water vapor transmission rate of the pressure-sensitive adhesive layer, the better, but the lower limit thereof is, for example, 100 g / (m 2 ·day).

[0059] The puncture strength of the pressure-sensitive adhesive layer is preferably 10 mN to 3000 mN, more preferably 30 mN to 2500 mN, even more preferably 50 mN to 2000 mN, and particularly preferably 100 mN to 2000 mN. Within these ranges, the pressure-sensitive adhesive layer functions well as a gas barrier layer, and shape change due to gas generation occurs favorably, resulting in the formation of a deformed portion with an excellent shape. Use of such a pressure-sensitive adhesive sheet allows for accurate peeling of small adherends (e.g., electronic components).

[0060] The transmittance of the pressure-sensitive adhesive layer for ultraviolet light with a wavelength of 360 nm is preferably 50% to 100%, and more preferably 60% to 95%.

[0061] C-1. Pressure-sensitive adhesive B1 Examples of the pressure-sensitive adhesive B1 include acrylic adhesives, rubber adhesives, vinyl alkyl ether adhesives, silicone adhesives, polyester adhesives, polyamide adhesives, urethane adhesives, and styrene-diene block copolymer adhesives. Among these, acrylic adhesives or rubber adhesives are preferred, and acrylic adhesives are more preferred. The adhesive B1 contained in the pressure-sensitive adhesive-containing adhesive layer may be the adhesives described in Section B-2.

[0062] C-2. Curing adhesive B2 Examples of the curable adhesive B2 include a heat-curable adhesive and an active energy ray-curable adhesive. Preferably, an active energy ray-curable adhesive is used. The adhesive layer formed by the active energy ray-curable adhesive is an adhesive layer formed by irradiating with active energy rays, i.e., an adhesive layer having a predetermined adhesive strength after irradiating with active energy rays.

[0063] Examples of resin materials constituting the active energy ray-curable pressure-sensitive adhesive include those described in Ultraviolet Curing System (by Kato Kiyomi, published by General Technology Center (1989)), Photocuring Technology (edited by Technical Information Association (2000)), JP 2003-292916 A, and Japanese Patent No. 4151850. More specifically, examples include a resin material (B2-1) containing a polymer as a base material and an active energy ray-reactive compound (monomer or oligomer), and a resin material (B2-2) containing an active energy ray-reactive polymer.

[0064] Examples of the polymer that can be used as the base material include rubber-based polymers such as natural rubber, polyisobutylene rubber, styrene-butadiene rubber, styrene-isoprene-styrene block copolymer rubber, reclaimed rubber, butyl rubber, polyisobutylene rubber, and nitrile rubber (NBR); silicone-based polymers; and acrylic-based polymers. These polymers may be used alone or in combination of two or more.

[0065] Examples of the active energy ray-reactive compound include photoreactive monomers or oligomers having multiple functional groups with carbon-carbon multiple bonds, such as acryloyl groups, methacryloyl groups, vinyl groups, allyl groups, and acetylene groups. Among these, compounds having ethylenically unsaturated functional groups are preferably used, and (meth)acrylic compounds having ethylenically unsaturated functional groups are more preferably used. Compounds having ethylenically unsaturated functional groups easily generate radicals when exposed to ultraviolet light, so that the use of such compounds allows for the formation of a pressure-sensitive adhesive layer that can be cured in a short period of time. Furthermore, the use of (meth)acrylic compounds having ethylenically unsaturated functional groups allows for the formation of a pressure-sensitive adhesive layer that has appropriate hardness after curing. Specific examples of photoreactive monomers or oligomers include (meth)acryloyl group-containing compounds such as trimethylolpropane tri(meth)acrylate, tetramethylolmethane tetra(meth)acrylate, pentaerythritol tri(meth)acrylate, pentaerythritol tetra(meth)acrylate, dipentaerythritol monohydroxypenta(meth)acrylate, dipentaerythritol hexa(meth)acrylate, 1,4-butanediol di(meth)acrylate, 1,6-hexanediol di(meth)acrylate, polyethylene glycol di(meth)acrylate, and urethane (meth)acrylate compounds; dimers to pentamers of the (meth)acryloyl group-containing compounds; etc. These compounds may be used alone or in combination of two or more.

[0066] The active energy ray-reactive compound may be a monomer such as epoxidized butadiene, glycidyl methacrylate, acrylamide, or vinylsiloxane, or an oligomer composed of such a monomer. The resin material (B2-1) containing such a compound can be cured by high-energy rays such as ultraviolet rays or electron beams.

[0067] Furthermore, the active energy ray-reactive compound may be a mixture of an organic salt such as an onium salt and a compound having multiple heterocycles in the molecule. When the mixture is irradiated with active energy rays (e.g., ultraviolet light or an electron beam), the organic salt is cleaved to generate ions, which act as initiating species to cause a ring-opening reaction of the heterocycles, forming a three-dimensional network structure. Examples of the organic salt include iodonium salts, phosphonium salts, antimonium salts, sulfonium salts, and borate salts. Examples of the heterocycle in the compound having multiple heterocycles in the molecule include oxirane, oxetane, oxolane, thiirane, and aziridine.

[0068] In the resin material (B2-1) containing the above-mentioned base polymer and active energy ray reactive compound, the content of the active energy ray reactive compound is preferably 0.1 to 500 parts by weight, more preferably 1 to 300 parts by weight, and even more preferably 10 to 200 parts by weight, relative to 100 parts by weight of the base polymer.

[0069] Examples of the active energy ray-reactive polymer include polymers having an active energy ray-reactive functional group having a carbon-carbon multiple bond, such as an acryloyl group, a methacryloyl group, a vinyl group, an allyl group, or an acetylene group. Preferably, a compound (polymer) having an ethylenically unsaturated functional group is used, and more preferably, a (meth)acrylic polymer having an acryloyl group or a methacryloyl group is used. Specific examples of polymers having an active energy ray-reactive functional group include polymers composed of polyfunctional (meth)acrylates. The polymer composed of the polyfunctional (meth)acrylate preferably has an alkyl ester having 4 or more carbon atoms in the side chain, more preferably an alkyl ester having 6 or more carbon atoms, even more preferably an alkyl ester having 8 or more carbon atoms, particularly preferably an alkyl ester having 8 to 20 carbon atoms, and most preferably an alkyl ester having 8 to 18 carbon atoms.

[0070] The resin material (B2-2) containing the active energy ray-reactive polymer may further contain the active energy ray-reactive compound (monomer or oligomer).

[0071] The active energy ray-curable adhesive can be cured by irradiation with active energy rays. In the pressure-sensitive adhesive sheet of the present invention, an adherend can be attached to the sheet before curing the adhesive, and then the adhesive can be cured by irradiating the sheet with active energy rays, thereby adhering the adherend to the sheet. Examples of active energy rays include gamma rays, ultraviolet rays, visible light, infrared rays (heat rays), radio waves, alpha rays, beta rays, electron beams, plasma flow, ionizing rays, and particle beams. Conditions such as the wavelength and dose of the active energy rays can be set as appropriate depending on the type of resin material used, etc. For example, an exposure dose of 10 to 1,000 mJ / cm is used. 2 The adhesive can be cured by irradiating it with ultraviolet light.

[0072] D. middle class Examples of the form of the intermediate layer include a resin layer and a layer having adhesiveness.

[0073] In one embodiment, the intermediate layer contains a thermoplastic resin. Such an intermediate layer may be a resin film containing a thermoplastic resin, a layer containing a pressure-sensitive adhesive C made of a thermoplastic resin, or the like. In another embodiment, the intermediate layer contains a curable resin (e.g., an ultraviolet-curable resin, a thermosetting resin). Such an intermediate layer may be a resin film containing a curable resin, a layer containing a curable pressure-sensitive adhesive D, or the like.

[0074] The thickness of the intermediate layer is preferably 0.1 μm to 50 μm, more preferably 1 μm to 40 μm, and even more preferably 1.5 μm to 30 μm. Within this range, an intermediate layer that functions well as a gas barrier layer can be formed.

[0075] The water vapor permeability of the intermediate layer is preferably 5000 g / (m 2 ·day) or less, and more preferably 4800g / (m2 ·day) or less, and more preferably 4500g / (m 2 ·day) or less, and more preferably 4200 g / (m 2 ·day) or less. Within this range, the intermediate layer functions well as a gas barrier layer, and a deformed portion with an excellent shape is formed. By using such a pressure-sensitive adhesive sheet, it is possible to peel off small adherends (e.g., electronic components) with high precision. The lower the water vapor transmission rate of the intermediate layer, the better, but the lower limit is, for example, 0.1 g / (m 2 ·day).

[0076] The puncture strength of the intermediate layer is preferably 300 mN to 5000 mN, more preferably 500 mN to 4500 mN, and even more preferably 1000 mN to 4000 mN. Within these ranges, the intermediate layer functions well as a gas barrier layer, and shape change due to gas generation occurs favorably, resulting in the formation of a deformed portion with an excellent shape. Use of such a pressure-sensitive adhesive sheet allows for accurate peeling of small adherends (e.g., electronic components).

[0077] The transmittance of the intermediate layer for ultraviolet light with a wavelength of 360 nm is preferably 50% to 100%, and more preferably 60% to 95%.

[0078] D-1. Intermediate layer as a resin layer The intermediate layer as a resin layer is formed, for example, from a resin film. Examples of resins that form the resin film include polyethylene terephthalate resins, polyolefin resins, styrene elastomer resins (e.g., SEBS, etc.), ultraviolet-curable resins, thermosetting resins, urethane resins, and epoxy resins. In one embodiment, the resin film is made of a thermoplastic resin.

[0079] The thickness of the resin film is preferably 0.1 μm to 50 μm, more preferably 0.5 μm to 30 μm, and even more preferably 1 μm to 20 μm.

[0080] D-2. Intermediate layer as adhesive layer Examples of the intermediate layer as a layer having adhesive properties include an intermediate layer containing a pressure-sensitive adhesive and an intermediate layer containing a curable adhesive. Preferably, an intermediate layer containing curable adhesive D is disposed. In particular, by combining an adhesive layer containing pressure-sensitive adhesive A with an intermediate layer containing curable adhesive D as the adhesive layer, it is possible to obtain a pressure-sensitive adhesive sheet that can form a better deformation portion upon laser light irradiation. The curable adhesive D can be the adhesive described in Section C-2.

[0081] The thickness of the intermediate layer as an adhesive layer is preferably 5 μm to 50 μm, and more preferably 5 μm to 30 μm.

[0082] E. Manufacturing method of adhesive sheet The pressure-sensitive adhesive sheet of the present invention can be produced by any appropriate method. For example, the pressure-sensitive adhesive sheet of the present invention can be produced by a method in which a gas-generating layer-forming composition containing pressure-sensitive adhesive A and an ultraviolet absorber is applied directly onto a predetermined substrate to form a gas-generating layer, and then a pressure-sensitive adhesive layer-forming composition containing pressure-sensitive adhesive B is applied onto the gas-generating layer to form a pressure-sensitive adhesive layer. In one embodiment, when the pressure-sensitive adhesive sheet has an intermediate layer, before forming the pressure-sensitive adhesive layer, a composition for forming an intermediate layer is applied onto the gas-generating layer to form the intermediate layer, and then a pressure-sensitive adhesive layer-forming composition is applied onto the intermediate layer to form the pressure-sensitive adhesive layer. Alternatively, each layer may be formed separately and then bonded together to form a pressure-sensitive adhesive sheet.

[0083] Any appropriate coating method can be used to apply the composition. For example, each layer can be formed by coating and then drying. Examples of the coating method include coating methods using a multi-coater, die coater, gravure coater, applicator, etc. Examples of the drying method include natural drying and heat drying. The heating temperature in heat drying can be set to any appropriate temperature depending on the properties of the substance to be dried. Furthermore, active energy ray irradiation (e.g., ultraviolet irradiation) can be performed depending on the form of each layer.

[0084] F. Electronic component processing methods The method for treating electronic components of the present invention includes adhering electronic components to the pressure-sensitive adhesive sheet and irradiating the pressure-sensitive adhesive sheet with laser light to peel the electronic components from the pressure-sensitive adhesive sheet. Examples of electronic components include semiconductor chips, LED chips, and MLCCs.

[0085] The electronic components can be peeled off selectively at their positions. Specifically, a plurality of electronic components are attached and fixed to the pressure-sensitive adhesive sheet, and then some of the electronic components are peeled off while the remaining electronic components remain fixed.

[0086] In one embodiment, the method for treating an electronic component of the present invention comprises applying a predetermined treatment to the electronic component after the electronic component is attached to the pressure-sensitive adhesive sheet and before the electronic component is peeled from the pressure-sensitive adhesive sheet. The treatment is not particularly limited, and examples thereof include grinding, dicing, die bonding, wire bonding, etching, vapor deposition, molding, circuit formation, inspection, testing, cleaning, transfer, alignment, repair, and device surface protection.

[0087] The size of the electronic component (area of ​​the attachment surface) is, for example, 1 μm 2 ~250,000μm 2 In one embodiment, the size of the electronic component (area of ​​the attachment surface) is 1 μm 2 ~6400μm 2 In another embodiment, an electronic component having a size (area of ​​the attachment surface) of 1 μm can be subjected to the treatment. 2 ~2500μm 2 of electronic components can be subjected to processing.

[0088] In one embodiment, as described above, a plurality of electronic components can be arranged on the adhesive sheet. The intervals between the electronic components are, for example, 1 μm to 500 μm. The present invention is advantageous in that the intervals can be narrowed to temporarily fix the object to be treated.

[0089] The laser light may be, for example, a UV laser light. The irradiation output of the laser light is, for example, 1 μJ to 1000 μJ. The wavelength of the UV laser light is, for example, 240 nm to 380 nm.

[0090] In one embodiment, the method for treating an electronic component includes, after peeling the electronic component, placing the electronic component on another sheet (for example, an adhesive sheet, a substrate, or the like). [Example]

[0091] The present invention will be described in detail below with reference to examples, but the present invention is not limited to these examples. Evaluation methods in the examples are as follows. In the following evaluations, pressure-sensitive adhesive sheets from which the separator had been peeled off were used. In the examples, "parts" and "%" are by weight unless otherwise specified.

[0092] (1) Transmittance In the case of a pressure-sensitive adhesive sheet having an intermediate layer, the pressure-sensitive adhesive sheet was placed in a spectrophotometer (product name "UV-VIS Ultraviolet-Visible Spectrophotometer SolidSpec3700", manufactured by Shimadzu Corporation) with incident light perpendicular to the gas barrier layer side of the sample, and the light transmittance in the wavelength range of 300 nm to 800 nm was measured. The transmittance at wavelengths of 360 nm and 500 nm was extracted from the obtained transmission spectrum. In the case of a pressure-sensitive adhesive sheet consisting only of a pressure-sensitive adhesive layer, the sheet was placed in the spectrophotometer with one release liner remaining, and then the transmission spectrum of the release liner alone was measured and subtracted to obtain the transmission spectrum of the pressure-sensitive adhesive layer alone. The transmittance at wavelengths of 360 nm and 500 nm was extracted from the obtained transmission spectrum. (2) Maximum gas generation peak temperature Approximately 0.5 mg of the adhesive sheet sample was placed in a heating furnace pyrolyzer, and the components volatilized by heating were analyzed by EGA-MS to obtain a mass chromatogram. The sample was heated from 40°C to 500°C at a rate of 10°C / min using a heating furnace pyrolyzer (manufactured by Frontier Labs, product name "PY2020iD"), and the maximum gas generation peak temperature was calculated from the mass chromatogram in the mass range m / z = 10 to 800 using a GC / MS analyzer (manufactured by JEOL, product name "JMS-T100GCV"). (3) Gasification start temperature The PSA sheet was heated in the same manner as in (2) above, and the gas generation onset temperature calculated from the EGA analysis was defined as the temperature at which the maximum gas generation peak in the EGA / MS chromatogram obtained from the EGA analysis reached half its maximum. (4) Types of gas generated The pressure-sensitive adhesive sheet sample was placed in an automatic sample combustion device (manufactured by Mitsubishi Chemical Analytech Co., Ltd., product name "AQF-2100H") and heated at 400°C for 30 minutes, and the generated gas was collected. The collected liquid was analyzed by ion chromatography to identify the type of generated gas. (5)5% weight loss temperature Using a differential thermal analyzer (manufactured by TA Instruments, trade name "Discovery TGA"), the adhesive sheet was heated at a temperature of 10°C / min in a N2 atmosphere at a flow rate of 25 ml / min, and the temperature at which the weight decreased by 5% was measured. (6)10% weight loss temperature Using a differential thermal analyzer (manufactured by TA Instruments, trade name "Discovery TGA"), the adhesive sheet was heated at a temperature of 10°C / min in a N2 atmosphere at a flow rate of 25 ml / min, and the temperature at which the weight lost 10% was measured. The 10% weight loss temperature was measured for each of the pressure-sensitive adhesive sheet and the gas-generating layer (UV absorber). (7) Water vapor permeability A measurement sample was prepared by pasting a sample over the opening of an Al jig with a 10mm x 10mm opening, and the measurement sample was placed between the first and second chambers of a water vapor permeability measurement device (manufactured by MOCON, product name "PERMATRAN-W3 / 34G") and evaluated using the MOCON measurement method. The temperature and humidity conditions were 30°C / 90%RH, the gas (water vapor) flow rate was 10.0±0.5cc / min, and the measurement time was 20 hours. The water vapor transmission rate was measured for each of the pressure-sensitive adhesive sheet, the pressure-sensitive adhesive layer, and the intermediate layer. (8) Surface shape change A measurement sample was obtained by attaching a glass plate (large slide glass S9112 (standard large white-edged polished No. 2) manufactured by Matsunami Glass Co., Ltd.) to the gas-generating layer side of the pressure-sensitive adhesive sheet (the side opposite the pressure-sensitive adhesive layer). A UV laser beam with a wavelength of 355 nm and a beam diameter of approximately 20 μmφ was used from the glass plate side of the measurement sample to pulse scan at an output of 0.80 mW and a frequency of 40 kHz to generate gas from the gas-generating layer. The pressure-sensitive adhesive layer surface (the gas-generating layer surface in Example 1 and Comparative Example 1) corresponding to any one pulse-scanned spot was observed with a confocal laser microscope 24 hours after laser beam irradiation, and the vertical displacement Y and horizontal displacement X (diameter; full width at half maximum) were measured. When the displacement Y is 8 μm or more, the releasability is remarkably excellent (◎ in the table); when the displacement Y is 0.6 μm or more and less than 8 μm, the releasability is good (◯ in the table); and when the displacement Y is less than 0.6 μm, the releasability is insufficient (× in the table). (9) Haze value In the case of a pressure-sensitive adhesive sheet having an intermediate layer, the release liner was peeled off, the sheet was set in a haze meter, and the haze value was measured with incident light perpendicular to the sample. In the case of a pressure-sensitive adhesive sheet consisting only of a pressure-sensitive adhesive layer, the sheet was set in the haze meter with one release liner remaining, and then the haze value of the release liner alone was measured and subtracted to obtain the haze value of the pressure-sensitive adhesive layer alone. When the haze value is 20% or less, the visibility of the adherend is good (◯ in the table). When the haze value is 20% or more and 50% or less, the visibility of the adherend is fair (△ in the table). When the haze value is 50% Greater than In this case, the adhesion visibility was evaluated as poor (in the table, marked x). (10) Adhesion (gas generating layer side) A measurement sample was obtained by laminating PET#25 to the adhesive layer side of the pressure-sensitive adhesive sheet. The adhesive strength of the gas-generating layer side of the measurement sample to SUS430 was measured according to JIS Z 0237:2000 (lamination conditions: one reciprocating motion with a 2 kg roller, tensile speed: 300 mm / min, peel angle: 180°). (11) Adhesive strength (adhesive layer) A measurement sample was obtained by laminating PET#25 to the gas-generating layer side of the pressure-sensitive adhesive sheet. The adhesive strength of the pressure-sensitive adhesive layer side of the measurement sample to SUS430 was measured according to JIS Z 0237:2000 (lamination conditions: 1 round trip with a 2 kg roller, tensile speed: 300 mm / min, peel angle: 180°). (12) In-plane uniformity of deformation As in (8) above, the gas generating layer was irradiated with UV laser light. A randomly selected 2mm x 2mm area of ​​deformed area was observed under a microscope, and if 90% or more of the convex parts were the same size it was rated as good (◯ in the table), if 80% to less than 90% of the convex parts were the same size it was rated as fair (△ in the table), and if less than 80% of the convex parts were the same size it was rated as bad (× in the table). "Same size" means that the difference in displacement X was within ±20%. (13) Position selectivity of deformation As in (8) above, the gas generating layer was irradiated with UV laser light. A single deformation in the laser irradiated area was evaluated as pass (◯), and multiple deformations in the periphery of the laser irradiated area were evaluated as fail (×). (14) Elastic modulus The elastic modulus was measured using a nanoindenter (Triboindenter TI-950 manufactured by Hysitron Inc.) by a single indentation method at a specified temperature (25°C) under the following measurement conditions: indentation speed of approximately 500 nm / sec, withdrawal speed of approximately 500 nm / sec, and indentation depth of approximately 1500 nm.

[0093] [Production Example 1] Preparation of gas generating layer forming composition a 30 parts by weight of 2-ethylhexyl acrylate, 70 parts by weight of ethyl acrylate, 4 parts by weight of 2-hydroxyethyl acrylate, 5 parts by weight of methyl methacrylate, and 0.2 parts by weight of benzoyl peroxide as a polymerization initiator were added to toluene, and the mixture was heated to 70°C to obtain a toluene solution of an acrylic copolymer (polymer A). A toluene solution of polymer A (polymer A: 100 parts by weight), 1.5 parts by weight of an isocyanate-based crosslinking agent (manufactured by Nippon Polyurethane Co., Ltd., trade name "Coronate L"), and 20 parts by weight of an ultraviolet absorber (manufactured by BASF, trade name "Tinuvin 477", structure: [Chemical Formula 1]) were mixed to prepare a gas-generating layer-forming composition a. The composition of gas-generating layer-forming composition a is shown in Table 1.

[0094] [ka]

[0095] [Production Example 2] Preparation of gas generating layer forming composition b Except for changing the blending amount of the UV absorber to 10 parts by weight, a gas generating layer forming composition b was prepared in the same manner as in Production Example 1. The composition of the gas generating layer forming composition b is shown in Table 1.

[0096] [Production Example 3] Preparation of gas generating layer forming composition c A gas generating layer-forming composition c was prepared in the same manner as in Production Example 1, except that 10 parts by weight of 2,4-bis(2-hydroxy-4-butoxyphenyl)-6-(2,4-dibutoxyphenyl)-1,3,5-triazine (trade name "TINUVIN 460", manufactured by BASF, structure: [Chemical Formula 2]) was used as the UV absorber. The composition of gas generating layer-forming composition c is shown in Table 1.

[0097] [ka]

[0098] [Production Example 4] Preparation of gas generating layer forming composition d Gas generating layer-forming composition d was prepared in the same manner as in Production Example 1, except that 20 parts by weight of a reaction product of 2-(4,6-bis(2,4-dimethylphenyl)-1,3,5-triazin-2-yl)-5-hydroxyphenyl and [(C10-C16 (mainly C12-C13) alkyloxy)methyl]oxirane (trade name "TINUVIN 400", manufactured by BASF, structure: [Chemical Formula 3]) was used as the UV absorber. The composition of gas generating layer-forming composition d is shown in Table 1.

[0099] [ka]

[0100] [Production Example 5] Preparation of gas generating layer forming composition e 30 parts by weight of 2-ethylhexyl acrylate, 70 parts by weight of methyl acrylate, 10 parts by weight of acrylic acid, and 0.2 parts by weight of benzoyl peroxide as a polymerization initiator were added to ethyl acetate, and the mixture was heated to 70°C to obtain an ethyl acetate solution of an acrylic copolymer (polymer B). A gas-generating layer-forming composition e was prepared by mixing an ethyl acetate solution of polymer B (polymer B: 100 parts by weight), 1 part by weight of an isocyanate-based crosslinking agent (manufactured by Nippon Polyurethane Co., Ltd., trade name "Coronate L"), and 20 parts by weight of an ultraviolet absorber (manufactured by BASF, trade name "Tinuvin 477"). The composition of gas-generating layer-forming composition e is shown in Table 1.

[0101] [Production Example 6] Preparation of gas generating layer forming composition f 95 parts by weight of 2-ethylhexyl acrylate, 5 parts by weight of acrylic acid, and 0.15 parts by weight of benzoyl peroxide as a polymerization initiator were added to ethyl acetate, and the mixture was heated to 70°C to obtain an ethyl acetate solution of an acrylic copolymer (polymer C). A gas-generating layer-forming composition f was prepared by mixing an ethyl acetate solution of polymer C (polymer C: 100 parts by weight), 1 part by weight of an isocyanate-based crosslinking agent (manufactured by Nippon Polyurethane Co., Ltd., trade name "Coronate L"), and 20 parts by weight of an ultraviolet absorber (manufactured by BASF, trade name "Tinuvin 477"). The composition of gas-generating layer-forming composition g is shown in Table 1.

[0102] [Production Example 7] Preparation of gas generating layer forming composition g 95 parts by weight of 2-ethylhexyl acrylate, 5 parts by weight of acrylic acid, and 0.15 parts by weight of benzoyl peroxide as a polymerization initiator were added to ethyl acetate, and the mixture was heated to 70°C to obtain an ethyl acetate solution of an acrylic copolymer (polymer C). A gas generating layer-forming composition g was prepared by mixing an ethyl acetate solution of polymer C (polymer C: 100 parts by weight), 0.1 parts by weight of an epoxy-based crosslinking agent (manufactured by Mitsubishi Gas Chemical Company, Inc., trade name "TETRAD-C"), and 20 parts by weight of an ultraviolet absorber (manufactured by BASF, trade name "Tinuvin 477"). The composition of gas generating layer-forming composition g is shown in Table 3.

[0103] [Production Example 8] Preparation of gas generating layer forming composition h Gas generating layer-forming composition h was prepared by mixing 100 parts by weight of maleic acid-modified styrene-ethylene-butylene-styrene block copolymer (SEBS: styrene moiety / ethylene-butylene moiety (weight ratio) = 30 / 70, acid value: 10 (mg-CH3ONa / g), Asahi Kasei Chemicals Corporation, product name "Tuftec M1913"), 3 parts by weight of epoxy-based crosslinker (Mitsubishi Gas Chemical Company, Inc., product name "TETRAD-C"), 20 parts by weight of ultraviolet absorber (BASF, product name "Tinuvin 477"), and toluene as a solvent. The composition of gas generating layer-forming composition h is shown in Table 3.

[0104] [Production Example 8'] Preparation of Gas Generating Layer-Forming Composition i 100 parts by weight of butyl acrylate, 5 parts by weight of acrylic acid, and 0.2 parts by weight of benzoyl peroxide as a polymerization initiator were added to toluene, and the mixture was heated to 70°C to obtain a toluene solution of an acrylic copolymer (polymer D). A toluene solution of polymer D (polymer D: 100 parts by weight), 0.1 parts by weight of an epoxy-based crosslinking agent (manufactured by Mitsubishi Gas Chemical Company, Inc., trade name "TETRAD-C"), and 20 parts by weight of an ultraviolet absorber (manufactured by BASF, trade name "Tinuvin 400") were mixed to prepare gas-generating layer-forming composition i. The composition of gas-generating layer-forming composition i is shown in Table 3.

[0105] [Production Example 8″] Preparation of Gas Generating Layer-Forming Composition j In the same manner as in Production Example 5, an ethyl acetate solution of an acrylic copolymer (Polymer B) was obtained. A gas-generating layer-forming composition e was prepared by mixing an ethyl acetate solution of polymer B (polymer B: 100 parts by weight), 1 part by weight of an epoxy-based crosslinking agent (manufactured by Nippon Polyurethane Co., Ltd., trade name "Coronate L"), and 20 parts by weight of an ultraviolet absorber (manufactured by BASF, trade name "Tinuvin 477"). The composition of gas-generating layer-forming composition e is shown in Table 1. A gas-generating layer-forming composition i was prepared by mixing an ethyl acetate solution of polymer B (polymer B: 100 parts by weight), 0.1 parts by weight of an epoxy-based crosslinking agent (manufactured by Mitsubishi Gas Chemical Company, Inc., trade name "TETRAD-C"), and 20 parts by weight of an ultraviolet absorber (manufactured by BASF, trade name "Tinuvin 400"). The composition of gas-generating layer-forming composition j is shown in Table 3.

[0106] [Production Example 8'''] Preparation of Gas Generating Layer-Forming Composition k 50 parts by weight of butyl acrylate, 50 parts by weight of ethyl acrylate, 5 parts by weight of acrylic acid, 0.1 parts by weight of 2-hydroxyethyl acrylate, 0.3 parts by weight of trimethylolpropane triacrylate, and 0.1 parts by weight of benzoyl peroxide as a polymerization initiator were added to toluene, and the mixture was heated to 70°C to obtain a toluene solution of an acrylic copolymer (Polymer E). A toluene solution of polymer E (polymer E: 100 parts by weight), 0.1 parts by weight of an epoxy-based crosslinking agent (manufactured by Mitsubishi Gas Chemical Company, Inc., trade name "TETRAD-C"), and 20 parts by weight of an ultraviolet absorber (manufactured by BASF, trade name "Tinuvin 400") were mixed to prepare gas-generating layer-forming composition i. The composition of gas-generating layer-forming composition k is shown in Table 3.

[0107] [Production Example 9] Preparation of Gas Generating Layer-Forming Composition I A gas generating layer-forming composition e was prepared in the same manner as in Production Example 1, except that 20 parts by weight of 2-[5-chloro-2H-benzotriazol-2-yl]-4-methyl-6-(tert-butyl)phenol (trade name "TINUVIN 326", manufactured by BASF) was used as the UV absorber. The composition of gas generating layer-forming composition I is shown in Table 1.

[0108] [Production Example 10] Preparation of heat-expandable microsphere-containing composition II A heat-expandable microsphere-containing composition II was prepared in the same manner as in Preparation Example 5, except that no ultraviolet absorber was added, the amount of crosslinking agent was 1.4 parts by weight, 30 parts by weight of heat-expandable microspheres (manufactured by Matsumoto Yushi Pharmaceutical Co., Ltd., trade name "Matsumoto Microsphere F-50D"), and 10 parts by weight of a terpene phenol-based tackifying resin (manufactured by Sumitomo Bakelite Co., Ltd., trade name "Sumilite Resin PR51732") were added.

[0109] [Production Example 11] Preparation of heat-expandable microsphere-containing composition III A heat-expandable microsphere-containing composition III was prepared in the same manner as in Preparation Example 8, except that 20 parts by weight of a terpene phenol tackifying resin (manufactured by Yasuhara Chemical Co., Ltd., product name "YS Polystar T160") was used instead of 10 parts by weight of a terpene phenol tackifying resin (manufactured by Sumitomo Bakelite Co., Ltd., product name "Sumilite Resin PR51732").

[0110] [Table 1]

[0111] [Production Example 12] Preparation of adhesive a In the same manner as in Production Example 1, a toluene solution of an acrylic copolymer (polymer A) was obtained. A toluene solution of polymer A (polymer A: 100 parts by weight), 3 parts by weight of an isocyanate-based crosslinking agent (manufactured by Nippon Polyurethane Co., Ltd., trade name "Coronate L"), and 5 parts by weight of a surfactant (manufactured by Kao Corporation, trade name "Exsepal IPP") were mixed to prepare adhesive a. The composition of adhesive a is shown in Table 2.

[0112] [Production Example 12'] Preparation of adhesive b In the same manner as in Production Example 6, a toluene solution of an acrylic copolymer (Polymer C) was obtained. A toluene solution of polymer C (polymer C: 100 parts by weight), 3 parts by weight of an isocyanate-based crosslinking agent (manufactured by Nippon Polyurethane Co., Ltd., product name "Coronate L"), and 1 part by weight of an epoxy-based crosslinking agent (manufactured by Mitsubishi Gas Chemical Company, Inc., product name "TETRAD-C") were mixed to prepare adhesive b. The composition of adhesive b is shown in Table 2.

[0113] [Production Example 13] Preparation of Adhesive I Except for changing the blending amount of the crosslinking agent to 1 part by weight and not adding a surfactant, adhesive I was prepared in the same manner as in Production Example 10. The composition of adhesive I is shown in Table 2.

[0114] [Table 2]

[0115] [Production Example 14] Preparation of intermediate layer-forming composition a In the same manner as in Production Example 5, an ethyl acetate solution of an acrylic copolymer (Polymer B) was obtained. An ethyl acetate solution of polymer B (polymer B: 100 parts by weight), 1 part by weight of an epoxy-based crosslinking agent (manufactured by Mitsubishi Gas Chemical Co., Ltd., trade name "Tetrad C"), 50 parts by weight of a UV oligomer (manufactured by Mitsubishi Chemical Corporation, trade name "Shikou UV-1700B"), and 3 parts by weight of a photopolymerization initiator (manufactured by BASF, trade name "Omnirad127") were mixed to prepare intermediate layer-forming composition a. The composition of intermediate layer-forming composition a is shown in Table 3.

[0116] [Production Example 15] Preparation of intermediate layer-forming composition b Intermediate layer composition b was obtained by mixing 100 parts by weight of maleic acid-modified styrene-ethylene-butylene-styrene block copolymer (SEBS: styrene moiety / ethylene-butylene moiety (weight ratio) = 30 / 70, acid value: 10 (mg-CH3ONa / g), Asahi Kasei Chemicals Corporation, product name "Tuftec M1913"), 3 parts by weight of epoxy-based crosslinker (Mitsubishi Gas Chemical Company, Inc., product name "TETRAD-C"), 3 parts by weight of fatty acid ester-based surfactant (Kao Corporation, product name "Exsepar IPP", molecular weight: 298.5, alkyl group carbon number: 16), and toluene as a solvent. The composition of intermediate layer composition b is shown in Table 3.

[0117] [Table 3]

[0118] [Example 1] The gas generating layer forming composition a obtained in Production Example 1 was applied to a polyethylene terephthalate film with a silicone release agent treated surface (manufactured by Toray Industries, Inc., product name "Cerapeel", thickness: 38 μm) so that the thickness after solvent evaporation (drying) would be 7 μm, and then dried to obtain an adhesive sheet consisting only of a gas generating layer on the polyethylene terephthalate film. The obtained pressure-sensitive adhesive sheet was subjected to the above evaluations (1) to (13). The results are shown in Table 4.

[0119] [Example 2] The adhesive a obtained in Production Example 10 was applied to a polyethylene terephthalate film (thickness: 75 μm) with a silicone release agent-treated surface so that the thickness after solvent evaporation (drying) would be 15 μm, and then dried to form an adhesive layer precursor layer a on the polyethylene terephthalate film. The gas generating layer forming composition a obtained in Production Example 1 was applied to a polyethylene terephthalate film (manufactured by Toray Industries, Inc., product name "Cerapeel", thickness: 38 μm) with a silicone release agent-treated surface so that the thickness after solvent evaporation (drying) would be 7 μm, and then dried to form a gas generating layer precursor layer a on the polyethylene terephthalate film. The pressure-sensitive adhesive layer precursor layer a and the gas-generating layer precursor layer a were laminated together between rolls to obtain a pressure-sensitive adhesive sheet (pressure-sensitive adhesive layer / gas-generating layer) sandwiched between polyethylene terephthalate films with silicone release agent-treated surfaces. The obtained pressure-sensitive adhesive sheet was subjected to the above evaluations (1) to (13). The results are shown in Table 4.

[0120] [Example 3] The adhesive a obtained in Production Example 10 was applied to a polyethylene terephthalate film (thickness: 75 μm) with a silicone release agent-treated surface so that the thickness after solvent evaporation (drying) would be 15 μm, and then dried to form an adhesive layer precursor layer a on the polyethylene terephthalate film. The intermediate layer forming composition a obtained in Production Example 12 was applied to a polyethylene terephthalate film with a silicone release agent treated surface (manufactured by Toray Industries, Inc., product name "Cerapeel", thickness: 38 μm) so that the thickness after solvent evaporation (drying) would be 15 μm, and then dried to form an intermediate layer precursor layer a on the polyethylene terephthalate film. Next, the pressure-sensitive adhesive layer precursor layer a and the intermediate layer precursor layer a are laminated together between rolls, and 500 mJ / cm 2 is applied from the intermediate layer precursor layer side. 2 The laminate precursor layer a was obtained by sandwiching the laminate between polyethylene terephthalate films having surfaces treated with a silicone release agent. The gas generating layer forming composition a obtained in Production Example 1 was applied to a polyethylene terephthalate film (manufactured by Toray Industries, Inc., product name "Cerapeel", thickness: 38 μm) with a silicone release agent-treated surface so that the thickness after solvent evaporation (drying) would be 7 μm, and then dried to form a gas generating layer precursor layer a on the polyethylene terephthalate film. After peeling off the polyethylene terephthalate film with a silicone release agent-treated surface on the intermediate layer precursor layer a side of the laminate precursor layer a, the intermediate layer precursor layer a of the laminate precursor layer a and the gas-generating layer precursor layer a were laminated together between rolls to obtain an adhesive sheet (adhesive layer / intermediate layer / gas-generating layer) sandwiched between polyethylene terephthalate films with silicone release agent-treated surfaces. The obtained pressure-sensitive adhesive sheet was subjected to the above evaluations (1) to (13). The results are shown in Table 4.

[0121] [Example 4] The adhesive a obtained in Production Example 10 was applied to a polyethylene terephthalate film (thickness: 75 μm) with a silicone release agent-treated surface so that the thickness after solvent evaporation (drying) would be 15 μm, and then dried to form an adhesive layer precursor layer a on the polyethylene terephthalate film. The intermediate layer forming composition b obtained in Production Example 13 was applied to a polyethylene terephthalate film with a silicone release agent treated surface (manufactured by Toray Industries, Inc., product name "Cerapeel", thickness: 38 μm) so that the thickness after solvent evaporation (drying) would be 15 μm, and then dried to form an intermediate layer precursor layer a on the polyethylene terephthalate film. Next, the pressure-sensitive adhesive layer precursor layer a and the intermediate layer precursor layer b were laminated together between rolls to obtain a laminate precursor layer b sandwiched between polyethylene terephthalate films with surfaces treated with a silicone release agent. The gas generating layer forming composition a obtained in Production Example 1 was applied to a polyethylene terephthalate film (manufactured by Toray Industries, Inc., product name "Cerapeel", thickness: 38 μm) with a silicone release agent-treated surface so that the thickness after solvent evaporation (drying) would be 7 μm, and then dried to form a gas generating layer precursor layer a on the polyethylene terephthalate film. After peeling off the polyethylene terephthalate film with a silicone release agent-treated surface on the intermediate layer precursor layer b side of the above-mentioned laminate precursor layer b, the intermediate layer precursor layer b of the laminate precursor layer b and the above-mentioned gas-generating layer precursor layer a were laminated together between rolls to obtain an adhesive sheet (adhesive layer / intermediate layer / gas-generating layer) sandwiched between polyethylene terephthalate films with silicone release agent-treated surfaces. The obtained pressure-sensitive adhesive sheet was subjected to the above evaluations (1) to (13). The results are shown in Table 4.

[0122] [Example 5] The adhesive a obtained in Production Example 10 was applied to a polyethylene terephthalate film (thickness: 75 μm) with a silicone release agent-treated surface so that the thickness after solvent evaporation (drying) would be 15 μm, and then dried to form an adhesive layer precursor layer a on the polyethylene terephthalate film. The gas generating layer forming composition a obtained in Production Example 1 was applied to a polyethylene terephthalate film (manufactured by Toray Industries, Inc., product name "Cerapeel", thickness: 38 μm) with a silicone release agent-treated surface so that the thickness after solvent evaporation (drying) would be 7 μm, and then dried to form a gas generating layer precursor layer a on the polyethylene terephthalate film. The pressure-sensitive adhesive layer precursor layer a was laminated between rolls onto one side of a polyethylene terephthalate film (manufactured by Toray Industries, Inc., trade name "Lumirror #2F51N", thickness: 2 μm). Next, the gas-generating layer precursor layer a was laminated between rolls onto the side of the polyethylene terephthalate film opposite to the pressure-sensitive adhesive layer precursor layer a. In this way, a pressure-sensitive adhesive sheet (pressure-sensitive adhesive layer / intermediate layer / gas-generating layer) sandwiched between polyethylene terephthalate films each having a surface treated with a silicone release agent was obtained. The obtained pressure-sensitive adhesive sheet was subjected to the above evaluations (1) to (13). The results are shown in Table 4.

[0123] [Example 6] A pressure-sensitive adhesive sheet was obtained in the same manner as in Example 5, except that gas-generating layer-forming composition b was used instead of gas-generating layer-forming composition a. The pressure-sensitive adhesive sheet obtained was subjected to the above-mentioned evaluations (1) to (13). The results are shown in Table 5.

[0124] [Example 7] A pressure-sensitive adhesive sheet was obtained in the same manner as in Example 5, except that gas-generating layer-forming composition c was used instead of gas-generating layer-forming composition a. The pressure-sensitive adhesive sheet obtained was subjected to the above-mentioned evaluations (1) to (13). The results are shown in Table 5.

[0125] [Example 8] A pressure-sensitive adhesive sheet was obtained in the same manner as in Example 5, except that composition d for forming a gas-generating layer was used instead of composition a for forming a gas-generating layer. The pressure-sensitive adhesive sheet obtained was subjected to the above-mentioned evaluations (1) to (13). The results are shown in Table 5.

[0126] [Example 9] A pressure-sensitive adhesive sheet was obtained in the same manner as in Example 5, except that composition e for forming a gas-generating layer was used instead of composition a for forming a gas-generating layer. The pressure-sensitive adhesive sheet obtained was subjected to the above-mentioned evaluations (1) to (13). The results are shown in Table 5.

[0127] [Example 10] A pressure-sensitive adhesive sheet was obtained in the same manner as in Example 5, except that composition f for forming a gas-generating layer was used instead of composition a for forming a gas-generating layer. The pressure-sensitive adhesive sheet obtained was subjected to the above-mentioned evaluations (1) to (13). The results are shown in Table 5.

[0128] [Example 11] A pressure-sensitive adhesive sheet was obtained in the same manner as in Example 1, except that composition g for forming a gas-generating layer was used instead of composition a for forming a gas-generating layer. The pressure-sensitive adhesive sheet obtained was subjected to the above-mentioned evaluations. The results are shown in Table 6.

[0129] [Example 12] A pressure-sensitive adhesive sheet was obtained in the same manner as in Example 1, except that composition h for forming a gas-generating layer was used instead of composition a for forming a gas-generating layer. The pressure-sensitive adhesive sheet obtained was subjected to the above-mentioned evaluations. The results are shown in Table 6.

[0130] [Table 4]

[0131] [Table 5]

[0132] [Table 6]

[0133] [Comparative Example 1] A pressure-sensitive adhesive sheet was obtained in the same manner as in Example 1, except that gas-generating layer-forming composition I was used instead of gas-generating layer-forming composition a. The pressure-sensitive adhesive sheet obtained was subjected to the above-mentioned evaluations (1) to (13). The results are shown in Table 7.

[0134] Comparative Example 2 A pressure-sensitive adhesive sheet was obtained in the same manner as in Example 5, except that gas-generating layer-forming composition I was used instead of gas-generating layer-forming composition a. The pressure-sensitive adhesive sheet obtained was subjected to the above-mentioned evaluations (1) to (13). The results are shown in Table 7.

[0135] Comparative Example 3 An adhesive sheet was obtained in the same manner as in Example 5, except that adhesive I was used instead of adhesive a, the adhesive layer was 10 μm thick, a 188 μm thick PET film was used as the intermediate layer, and a 48 μm thick gas-generating layer was formed using heat-expandable microsphere-containing composition II instead of gas-generating layer-forming composition a. The obtained adhesive sheet was subjected to the above-mentioned evaluations (1) to (13). The results are shown in Table 7.

[0136] Comparative Example 4 An adhesive sheet was obtained in the same manner as in Example 5, except that adhesive I was used instead of adhesive a, the thickness of the adhesive layer was 10 μm, a 100 μm PET film was used as the intermediate layer, and a 48 μm gas-generating layer was formed using heat-expandable microsphere-containing composition III instead of gas-generating layer-forming composition a. The obtained adhesive sheet was subjected to the above-mentioned evaluations (1) to (13). The results are shown in Table 7.

[0137] [Table 7] [Explanation of symbols]

[0138] 10 Gas generation layer 20 adhesive layer 30 Middle Class 100, 100', 200 adhesive sheet

Claims

1. A pressure-sensitive adhesive sheet having a gas generating layer that generates gas when irradiated with laser light, The haze value is 50% or less, the gas generating layer contains an ultraviolet absorber; the ultraviolet absorber is a benzotriazole-based ultraviolet absorber, a benzophenone-based ultraviolet absorber, a triazine-based ultraviolet absorber, a salicylate-based ultraviolet absorber, or a cyanoacrylate-based ultraviolet absorber; The pressure-sensitive adhesive sheet has an ultraviolet transmittance of 30% or less at a wavelength of 360 nm. Adhesive sheet.

2. 2. The pressure-sensitive adhesive sheet according to claim 1, wherein the gas generating layer has a thickness of 0.1 μm to 50 μm.

3. The pressure-sensitive adhesive sheet according to claim 1 or 2, wherein the gas-generating layer is a layer capable of absorbing ultraviolet light.

4. The pressure-sensitive adhesive sheet according to any one of claims 1 to 3, wherein the transmittance at a wavelength of 500 nm is 50% to 100%.

5. The pressure-sensitive adhesive sheet according to claim 1 , wherein the gas generating layer is a layer that generates a hydrocarbon gas.

6. 6. The pressure-sensitive adhesive sheet according to claim 1, wherein the gas generation layer has a gasification initiation temperature of 150°C to 500°C.

7. The pressure-sensitive adhesive sheet according to any one of claims 1 to 6, wherein the 10% weight loss temperature is 200°C to 500°C.

8. A pressure-sensitive adhesive layer is further provided on at least one side of the gas generating layer, The pressure-sensitive adhesive layer is a layer whose surface is deformed when the pressure-sensitive adhesive sheet is irradiated with laser light. The pressure-sensitive adhesive sheet according to any one of claims 1 to 7.

9. The pressure-sensitive adhesive sheet according to claim 8, wherein the pressure-sensitive adhesive layer has a thickness of 0.1 μm to 50 μm.

10. The pressure-sensitive adhesive sheet according to claim 8 , wherein the pressure-sensitive adhesive layer foams when irradiated with laser light.

11. A method for treating electronic components, comprising: adhering an electronic component to the adhesive sheet according to claim 1; and irradiating the adhesive sheet with laser light to peel the electronic component from the adhesive sheet.

12. The method for processing an electronic component according to claim 11, wherein the peeling of the electronic component is performed selectively at a position.

13. After the electronic component is attached to the pressure-sensitive adhesive sheet, and before the electronic component is peeled off from the pressure-sensitive adhesive sheet, performing a predetermined process on the electronic component; The method for processing electronic components according to claim 12.

14. The method for processing electronic components according to claim 13, wherein the processing is grinding, dicing, die bonding, wire bonding, etching, vapor deposition, molding, circuit formation, inspection, testing, cleaning, transfer, alignment, repair, or device surface protection.

15. The method for treating an electronic component according to claim 11 , further comprising the step of: peeling the electronic component from the adhesive sheet, and then placing the electronic component on another sheet.

Images