Gas generating agent, adhesive composition, and adhesive sheet

Abstract

The present invention provides a gas generating agent for use in adhesive compositions that can form an adhesive layer that has sufficient adhesive strength during use while exhibiting excellent ease of removal from the adherend when peeled off. [Solution] A gas generating agent comprising a gas generating section having a specific structure, and a fluorinated aliphatic hydrocarbon group having 2 to 8 carbon atoms to which fluorine atoms are directly bonded, and which may contain ether bonds (-O-) in the carbon chain, or an organopolysiloxane group, having a maximum molar extinction coefficient of 7000 or more at wavelengths of 240 to 450 nm, and generating gas upon light irradiation.

Description

[Technical Field]

[0001] This disclosure relates to a gas generating agent, an adhesive composition containing the gas generating agent, and an adhesive sheet. [Background technology]

[0002] Adhesive compositions containing adhesive components are widely used in binders for adhesives, sealants, paints, and coatings, as well as in adhesive materials such as adhesive tapes and adhesive sheets. The performance requirements for these adhesive compositions vary depending on their application, but in some applications, it is necessary for them to exhibit adhesion only for the required period and then be easily removable.

[0003] For example, in the semiconductor chip manufacturing process, it has been proposed to efficiently carry out the work by reinforcing the thick film wafer, which has been cut from a high-purity silicon single crystal, by bonding it to an adhesive sheet, in the process of polishing a thick film wafer cut from a high-purity silicon single crystal to a predetermined thickness to create a thin film wafer. Also, when dicing a thin film wafer ground to a predetermined thickness into individual semiconductor chips, an adhesive sheet called a dicing tape is used as a temporary support. Furthermore, in the manufacturing process of multilayer ceramic capacitors (MLCCs), when a sheet of dielectric paste with electrodes printed on it is laminated, pressed, and then cut to form a chip, an adhesive sheet is used as a temporary support. In addition, in the manufacturing process of flexible printed circuit boards, an adhesive sheet is used as a temporary process support. Moreover, in the manufacturing process of flexible printed circuit boards and flexible organic EL displays, a protective sheet is sometimes used to protect the surface of the substrate to prevent damage to the substrate, contamination by chemicals, and deterioration of the substrate due to chemicals or heating used during the manufacturing process, and an adhesive sheet is used as such a temporary protective sheet.

[0004] The process adhesives used in such manufacturing processes are required to adhere firmly during the process, while also being able to be peeled off without damaging the resulting thin-film wafers or semiconductor chips after the process is completed (hereinafter also referred to as "high adhesion and easy peelability").

[0005] As an adhesive material aimed at high adhesion and easy peeling, Patent Document 1 discloses an adhesive tape using a photocurable adhesive that hardens and loses adhesive strength when irradiated with light such as ultraviolet light. Such adhesive tapes adhere during the processing process, but can be easily peeled off by irradiating with ultraviolet light or the like. However, with such adhesive tapes, the decrease in adhesive strength after irradiation with ultraviolet light or the like is insufficient, making it difficult to peel them off without damaging thin film wafers, semiconductor chips, etc.

[0006] Furthermore, Patent Document 2 discloses an adhesive tape having an adhesive layer containing a gas generating agent, such as an azo compound, which generates gas when stimulated. When this adhesive tape is stimulated, the gas generated from the gas generating agent is released to the interface between the tape surface and the adherend, and the pressure from this gas causes at least a portion of the adherend to peel off, thereby allowing for peeling without damaging thin film wafers, semiconductor chips, etc., and without leaving any adhesive residue.

[0007] Furthermore, Patent Document 3 proposes an adhesive composition that has high adhesion, can be easily peeled off, and also has excellent heat resistance, using a tetrazole compound that generates a gas when irradiated with light and has high heat resistance. However, even when using the above-mentioned azo compounds or tetrazole compounds, the reduction in peeling force was insufficient, or a large amount had to be added to sufficiently reduce the peeling force. [Prior art documents] [Patent Documents]

[0008] [Patent Document 1] Japanese Patent Application Publication No. 5-32946 [Patent Document 2] Japanese Patent Publication No. 2003-231872 [Patent Document 3] International Publication No. 2011 / 118506 [Overview of the Initiative] [Problems that the invention aims to solve]

[0009] Due to the increasing precision and complexity of various electronic components, the substrates themselves are becoming thinner, more integrated, and miniaturized. As a result, the substrates themselves and their surfaces are becoming more susceptible to damage. Therefore, there is a growing need for adhesives that adhere firmly during the manufacturing process while also being easily detachable after the process is completed, minimizing stress on the substrate. However, there is a trade-off between improving adhesive strength and improving ease of peeling, and conventional adhesive materials aimed at high adhesion and easy peeling still lack sufficient peelability.

[0010] This disclosure has been made in view of the above circumstances, and aims to provide a gas generating agent that generates gas upon light irradiation, which can improve the effect of imparting peelability to a surface; an adhesive composition using the gas generating agent that can form an adhesive layer that has sufficient adhesive strength during use but is easily peelable from the adherend when peeled off; and an adhesive sheet using the adhesive composition that has sufficient adhesive strength during use but is easily peelable from the adherend. [Means for solving the problem]

[0011] One embodiment of the present disclosure provides a gas generating agent that is represented by at least one of the following general formulas (1) and (2), has a maximum molar extinction coefficient of 7000 or more at wavelengths of 240 to 450 nm, and generates gas upon light irradiation.

[0012] [ka] (In general formulas (1) and (2), Each A independently represents a gas generating unit represented by the following general formulas (A-1), (A-2), or (A-3): L each independently represents a direct bond or a divalent linking group. Q 1 represents a monovalent fluorinated aliphatic hydrocarbon group in which the number of carbon atoms directly bonded to fluorine atoms is 2 to 8, may contain an ether bond (-O-) in the carbon chain, and may have a substituent, or represents a monovalent organopolysiloxane group. Q 2 represents a divalent fluorinated aliphatic hydrocarbon group in which the number of carbon atoms directly bonded to fluorine atoms is 2 to 8, may contain an ether bond (-O-) in the carbon chain, or represents a divalent organopolysiloxane group. )

[0013]

Chemical formula

[0014] In the gas generating agent of the present disclosure, in the above general formulas (1) and (2), Q 1 represents any one of the monovalent fluorinated aliphatic hydrocarbon groups represented by the following (Rf-1) to (Rf-5), or represents a monovalent organopolysiloxane group represented by the following (Si-1).2 This may represent a divalent fluorinated aliphatic hydrocarbon group represented by (Rf-6) below, or a divalent organopolysiloxane group represented by (Si-2) below.

[0015] [ka] (In equations (Rf-1), (Rf-2), and (Rf-3), n independently represents an integer from 2 to 8; in equation (Rf-4), n' represents an integer from 4 to 10; in (Rf-5), n is an integer from 0 to 8, n'' is an integer from 0 to 4, m is an integer from 0 to 8, where n+n''×m represents an integer from 2 to 8, J 1 represents a hydrogen atom, fluorine atom, hydroxyl group, amino group, carboxyl group, or (meth)acryloyloxy group, and in (Rf-6), n is an integer from 1 to 8, n'' is an integer from 0 to 7, m is an integer from 0 to 7, where n + n'' × m represents an integer from 2 to 8.

[0016] [ka] (In equations (Si-1) and (Si-2), R 11 Each of these independently represents a monovalent hydrocarbon group having 1 to 20 carbon atoms, which may have substituents, a hydrogen atom, a hydroxyl group, an alkoxy group having 1 to 20 carbon atoms, or a group represented by the following general formula (Si-3), J 2 (where a represents a monovalent hydrocarbon group having 1 to 20 carbon atoms, a hydrogen atom, a hydroxyl group, an alkoxy group having 1 to 20 carbon atoms, an amino group, a carboxyl group, or a (meth)acryloyloxy group, which may have substituents. Each of these independently represents a number from 1 to 100.)

[0017] [ka] (In equation (Si-3), R 12 Each of these independently represents a monovalent hydrocarbon group having 1 to 20 carbon atoms, a hydrogen atom, a hydroxyl group, or an alkoxy group having 1 to 20 carbon atoms, which may have substituents, and b represents a number from 0 to 100.

[0018] In the gas generating agent of the present disclosure, in the general formulas (1) and (2), L may independently represent a hydrocarbon group having 1 to 22 carbon atoms, which may be directly bonded, or which may contain one or more selected from the group consisting of -SCH2CH2COO-, -SCH2CH(CH3)COO-, -SCH2CH(OH)CH2-, -OCH2CH(OH)CH2-, -SCH(CH3)O-, -OCH(CH3)O-, -COO-, -CONH-, -COS-, -SO2NH-, or -O- and -S-, and which may be substituted with a hydroxyl group, or a combination thereof.

[0019] Another embodiment of the present disclosure provides an adhesive composition containing an adhesive component and a gas generating agent of one embodiment of the present disclosure.

[0020] Other embodiments of the present disclosure include an adhesive layer and a substrate or release sheet on one side of the adhesive layer. The present invention provides an adhesive sheet in which the adhesive layer is an adhesive composition or a cured product thereof containing an adhesive component and a gas generating agent according to one embodiment of the present disclosure, and the adhesive layer has the property of decreasing in adhesive strength from its initial adhesive strength upon light irradiation.

[0021] The adhesive composition in the adhesive sheet of this disclosure may contain a photocurable component and a photoinitiator.

[0022] The adhesive composition in the adhesive sheet of this disclosure may contain a thermal crosslinking agent.

[0023] The adhesive sheet of this disclosure may further include a release sheet on the side of the adhesive layer opposite to the substrate or release sheet side. [Effects of the Invention]

[0024] According to embodiments of this disclosure, it is possible to provide a gas generating agent that generates gas upon light irradiation, which can improve the effect of imparting peelability to the surface; an adhesive composition using the gas generating agent that can form an adhesive layer that has sufficient adhesive strength during use but is easily peelable from the adherend when peeled off; and an adhesive sheet using the adhesive composition that has sufficient adhesive strength during use but is easily peelable from the adherend. [Brief explanation of the drawing]

[0025] [Figure 1] This is a schematic cross-sectional view showing an example of an adhesive sheet in this disclosure. [Figure 2] This is a schematic cross-sectional view showing another example of an adhesive sheet in this disclosure. [Modes for carrying out the invention]

[0026] The embodiments and examples of this disclosure will be described below with reference to the drawings. However, this disclosure can be implemented in many different ways, and should not be interpreted as being limited to the embodiments and examples described below. In addition, the drawings may be schematically represented in terms of width, thickness, shape, etc. of each part compared to the actual embodiment in order to make the explanation clearer, but these are merely examples and should not limit the interpretation of this disclosure. Furthermore, in this specification and each drawing, elements similar to those described above in previously shown drawings will be denoted by the same reference numerals, and detailed explanations may be omitted as appropriate. Also, for the convenience of explanation, the terms "up" or "down" may be used in the explanation, but the up and down directions may be reversed. In this specification, when a component or region is said to be "above (or below)" another component or region, unless otherwise specified, this includes not only cases where it is directly above (or below) the other component, but also cases where it is above (or below) the other component, that is, cases where another component is included between them above (or below) the other component.

[0027] In this disclosure, (meth)acrylic means acrylic or methacrylic, respectively, and (meth)acrylate means acrylate or methacrylate, respectively. Furthermore, in this specification, "sheet" also includes a component called "film." Furthermore, "film" also includes a component called "sheet." In addition, "sheet surface (film surface)" refers to the surface that coincides with the planar direction of the sheet-like (film-like) component in question when viewed as a whole and in a broad sense. In this disclosure, "light" includes light that contains ultraviolet light. The gas generating agent, adhesive composition, and adhesive sheet of this disclosure will be described in detail below.

[0028] A. Gas Generating Agent The gas generating agent of one embodiment of the present disclosure is represented by at least one of the following general formulas (1) and (2), has a maximum molar extinction coefficient of 7000 or more at wavelengths of 240 to 450 nm, and is a gas generating agent that generates gas upon light irradiation.

[0029] [ka] (In general formulas (1) and (2), Each A independently represents a gas generating unit represented by the following general formulas (A-1), (A-2), or (A-3): Each L independently represents either a direct bond or a divalent linking group. Q 1 This represents a monovalent fluorinated aliphatic hydrocarbon group or a monovalent organopolysiloxane group, in which the number of carbon atoms directly bonded to a fluorine atom is 2 to 8, and which may contain an ether bond (-O-) in the carbon chain and may have substituents. Q 2 This represents a divalent fluorinated aliphatic hydrocarbon group or a divalent organopolysiloxane group in which the number of carbon atoms directly bonded to the fluorine atom is 2 to 8, and which may contain ether bonds (-O-) in the carbon chain.

[0030] [ka] (In general formulas (A-1), (A-2), and (A-3), R 1 R is an aromatic group having 3 to 20 carbon atoms, which may have substituents. 2 Each is independently a hydrogen atom or a hydrocarbon group having 1 to 20 carbon atoms which may have substituents, R 3 Each of these is independently a hydrocarbon group having 1 to 20 carbon atoms, which may have substituents, a cyano group, or a -COOR group. 5 , or -CONR 6 R 7 , R 4 This may have substituents, such as a hydrocarbon group having 1 to 20 carbon atoms, a cyano group, or a -COOR group. 5 ,-CONR 6 R 7 , or the aforementioned -LQ 1 Represents R 5 and R 7 Each of these independently represents a hydrocarbon group having 1 to 20 carbon atoms, which may have substituents, and R 6 (This represents a hydrogen atom or a hydrocarbon group with 1 to 5 carbon atoms.)

[0031] The gas generating agent of this disclosure has a gas generating portion having the specific structure described above and the specific fluorinated aliphatic hydrocarbon group or the specific organopolysiloxane group, and has a maximum molar extinction coefficient of 7000 or more at wavelengths of 240 to 450 nm, and is a gas generating agent that generates gas upon light irradiation, thereby improving the effect of imparting peelability to the surface. The reason for this is not clear, but it is presumed to be as follows. In adhesive layers containing a gas-generating agent for high adhesion and easy peeling, irradiating with light after use releases gas generated from the gas-generating agent to the surface of the adhesive layer, i.e., the interface with the adherend, and the pressure of this gas causes at least a portion of the adherend to peel off. Due to the release of this gas to the surface of the adhesive layer, the contact area between the adhesive layer and the adherend is reduced, making it easier to peel off. In conventional adhesive layers containing a gas-generating agent, since the gas-generating agent is uniformly dispersed in the adhesive layer, even when irradiated with light, gas is not easily released from the gas-generating agent present inside the adhesive layer to the surface of the adhesive layer. As a result, the amount of gas generated at the surface of the adhesive layer is insufficient, leading to insufficient reduction in peeling force and inadequate peelability. Increasing the content of the gas-generating agent in the adhesive layer to increase the amount of gas generated at the surface of the adhesive layer leads to a decrease in the adhesive strength of the adhesive layer or clouding of the adhesive layer, thus limiting the improvement of peeling force by adding a gas-generating agent. In contrast, the gas generating agent of this disclosure has a specific fluorinated aliphatic hydrocarbon group or a specific organopolysiloxane group introduced into the gas generating portion having the specific structure, making it easy to localize on the surface. In an adhesive layer containing the gas generating agent of this disclosure, since the gas generating agent is easily localized on the surface of the adhesive layer, when light is irradiated, the gas generating agent localized on the surface of the adhesive layer generates gas, and this gas is easily released onto the surface of the adhesive layer. In an adhesive layer containing the gas generating agent of this disclosure, the amount of gas generated on the surface of the adhesive layer is efficiently increased, resulting in excellent ease of peeling from the adherend. Since the gas generating agent of this disclosure is easily localized on the surface of the adhesive layer, the amount of gas generated on the surface of the adhesive layer can be efficiently increased without increasing the content of the gas generating agent, thus suppressing a decrease in the adhesive strength and clouding of the adhesive layer. Thus, it is presumed that the gas generating agent of this disclosure can improve the effect of imparting peelability to the surface.

[0032] The gas generating agent of this disclosure can generate gas by decomposition upon light irradiation. The gas generating agent of this disclosure has a maximum molar extinction coefficient of 7000 or more at wavelengths of 240 to 450 nm, and can therefore efficiently absorb light including ultraviolet light, and can efficiently decompose and generate gas upon irradiation with light including ultraviolet light. In general formulas (1) and (2), A independently represents a gas generating unit represented by the general formulas (A-1), (A-2), or (A-3). The gas generating unit represented by the general formula (A-1) generates nitrogen gas when the tetrazole ring is decomposed by light irradiation. The gas generating unit represented by the general formula (A-2) generates nitrogen gas when irradiated with light, as the -(C=O)-(C=N2)- bond decomposes into -(C=C=O)- bond and nitrogen gas. The gas generating unit represented by the general formula (A-3) above decomposes at the azo group portion upon light irradiation, generating nitrogen gas.

[0033] In general formula (A-1), R 1 In this example, the C3-C20 aromatic group, which may have substituents, can be appropriately selected such that the compound satisfies the maximum value of the specified molar extinction coefficient. Aromatic groups having 3 to 20 carbon atoms include aromatic hydrocarbon groups and aromatic heterocyclic groups.

[0034] Examples of aromatic hydrocarbon groups include aromatic hydrocarbon groups having 6 to 20 carbon atoms, with aromatic hydrocarbon groups having 6 to 12 carbon atoms being preferred. Examples include phenyl group, biphenyl group, naphthyl group, anthryl group, phenanthryl group, fluorenyl group, naphthylphenyl group, pyrenyl group, and the like. Examples of aromatic heterocyclic groups include aromatic heterocyclic groups having 3 to 20 carbon atoms and containing at least one nitrogen atom, an oxygen atom, and a sulfur atom, with aromatic heterocyclic groups having 3 to 10 carbon atoms being preferred. Examples include pyrrolyl groups, furyl groups, thienyl groups, pyrazolyl groups, imidazolyl groups, oxazolyl groups, isoxazolyl groups, thiazolyl groups, isothiazolyl groups, and carbazole groups. Examples of substituents that the aromatic group may have include halogen atoms such as F, Cl, and Br, nitro groups, alkyl groups, alkenyl groups, aralkyl groups, alkoxy groups such as methoxy groups, tertiary amino groups such as diphenylamino groups, and acyl groups such as benzoyl groups. The alkyl groups, alkenyl groups, and aralkyl groups may be the same as the C1-C20 alkyl groups, C2-C20 alkenyl groups, and aralkyl groups described later, but C1-C14 alkyl groups, C2-C14 alkenyl groups, and C7-C14 aralkyl groups are preferred. By appropriately selecting substituents for the aromatic group, the light absorption wavelength can be changed or the compatibility with other components can be improved. Examples of substituents that change the light absorption wavelength to the longer wavelength side include alkoxy groups such as methoxy groups, diarylamino groups such as diphenylamino groups, and acyl groups such as benzoyl groups.

[0035] R 1 As such, the absorption wavelength range can be extended and made longer wavelength, and the aromatic hydrocarbon group may have substituents, and among them, an aromatic hydrocarbon group may have substituents, and is more preferably a phenyl group, naphthyl group, or anthryl group, which may have substituents. When irradiated with light including ultraviolet light, it is more preferably a naphthyl group because it has high sensitivity and improves the gas generation efficiency.

[0036] R 2 Examples of C1-C20 hydrocarbon groups that may have substituents include C1-C20 alkyl groups, C2-C20 alkenyl groups, aralkyl groups, and aryl groups. The C1-C20 alkyl group may be linear, branched, or cyclic. Examples include methyl group, ethyl group, n-propyl group, isopropyl group, n-butyl group, 2-ethylhexyl group, cyclopentyl group, cyclohexyl group, bornyl group, isobornyl group, dicyclopentanyl group, adamantyl group, and lower alkyl group-substituted adamantyl group. The aforementioned alkenyl group having 2 to 20 carbon atoms may be linear, branched, or cyclic. Examples of such alkenyl groups include vinyl groups, allyl groups, and propenyl groups. There are no limitations on the position of the double bond of the alkenyl group, but from the viewpoint of reactivity, it is preferable that the double bond be at the terminal end of the alkenyl group. As an aryl group, the R 1 The aromatic hydrocarbon group may be the same as in the above, but phenyl groups, biphenyl groups, naphthyl groups, etc., are preferably used. Examples of aralkyl groups include benzyl, phenethyl, naphthylmethyl, and biphenylmethyl groups. The number of carbon atoms in the aralkyl group is preferably 7 to 20, and more preferably 7 to 14.

[0037] Examples of substituents that the hydrocarbon group may have include halogen atoms such as F, Cl, and Br, and nitro groups. The substituent on the aromatic ring, such as the aryl group or aralkyl group, may also be the alkyl group. Note that the preferred number of carbon atoms mentioned above does not include the number of carbon atoms of substituents.

[0038] R 2 In terms of solubility in organic solvents, reactivity, and nitrogen content per molecule, it is preferable that the group consists of a hydrogen atom or a hydrocarbon group having 1 to 6 carbon atoms, which may have substituents, and all three may be hydrogen atoms.

[0039] R 3 , R 4 , R 5 and R 7 The hydrocarbon group having 1 to 20 carbon atoms that may have substituents in the above R is 2 Examples include hydrocarbon groups having 1 to 20 carbon atoms that may have substituents, similar to those in the above. R 6 The hydrocarbon group having 1 to 5 carbon atoms in the above R 2 Examples include hydrocarbon groups having 1 to 20 carbon atoms that may have substituents, similar to those corresponding to hydrocarbon groups having 1 to 5 carbon atoms. R 4 -LQ in 1 This may be the same as described later.

[0040] R 5 and R 7 In terms of solubility in organic solvents and nitrogen content per molecule, hydrocarbon groups having 1 to 20 substituents are preferred, and hydrocarbon groups having 1 to 10 substituents are more preferred. R 6 From the viewpoint of the nitrogen content contained in one molecule, it is preferably a hydrogen atom or a methyl group, and more preferably a hydrogen atom.

[0041] R 3 In terms of solubility in organic solvents and nitrogen content per molecule, the hydrocarbon group is preferably a hydrocarbon group having 1 to 10 substituents, or a cyano group, more preferably a hydrocarbon group having 1 to 5 substituents, and may be a methyl group or an ethyl group.

[0042] R 4 In terms of solubility in organic solvents and localization on the surface of the adhesive layer, among them, hydrocarbon groups which may have substituents with 1 to 10 carbon atoms or the -LQ 1 Preferably, the -LQ 1 It is preferable that it be so.

[0043] In general formulas (1) and (2), A preferably represents the gas generating unit represented by general formula (A-1) in terms of heat resistance and nitrogen content per molecule. Examples of gas generating units represented by the general formula (A-1) are given below, but are not limited to these.

[0044] [ka]

[0045] On the other hand, in the above general formulas (1) and (2), Q 1 Q represents a monovalent fluorinated aliphatic hydrocarbon group or a monovalent organopolysiloxane group in which the number of carbon atoms directly bonded to the fluorine atom is 2 to 8, and which may contain an ether bond (-O-) in the carbon chain and may have substituents. 2 This represents a divalent fluorinated aliphatic hydrocarbon group or a divalent organopolysiloxane group in which the number of carbon atoms directly bonded to a fluorine atom is 2 to 8, and which may contain an ether bond (-O-) in the carbon chain.

[0046] Q 1 and Q 2 In this context, fluorinated aliphatic hydrocarbon groups include linear or branched saturated or unsaturated fluorinated aliphatic hydrocarbon groups. Q 1 and Q 2 In this context, a fluorinated aliphatic hydrocarbon group may contain carbon atoms that are not directly bonded to a fluorine atom, as long as the number of carbon atoms directly bonded to a fluorine atom is between 2 and 8. For example, if an alkynyl group is included in the fluorinated aliphatic hydrocarbon group, it will contain carbon atoms that are not directly bonded to a fluorine atom.

[0047] Q 1 and Q 2 In this context, the fluorinated aliphatic hydrocarbon group does not necessarily have to have all carbon atoms directly bonded to it replaced by fluorine atoms; some of them may contain hydrogen atoms or substituents. Examples of such substituents include reactive groups used when connecting to the gas generation unit, such as hydroxyl groups, amino groups, carboxyl groups, or (meth)acryloyloxy groups, vinyl ether groups, phosphoric acid groups, epoxy groups, etc.

[0048] Q 1 and Q 2In the fluorinated aliphatic hydrocarbon group, it is preferable that it contains four or more fluorine atoms, and more preferably six or more, from the viewpoint of surface localization effect. The number of fluorine atoms in the fluorinated aliphatic hydrocarbon group may be 17 or less, or 16 or less.

[0049] Q 1 and Q 2 In terms of fluorinated aliphatic hydrocarbons, Q is the most effective in terms of surface localization. 1 Q is one of the following monovalent fluorinated aliphatic hydrocarbon groups represented by (Rf-1) to (Rf-5), and 2 Examples include the divalent fluorinated aliphatic hydrocarbon group represented by (Rf-6) below.

[0050] [ka] (In equations (Rf-1), (Rf-2), and (Rf-3), n independently represents an integer from 2 to 8; in equation (Rf-4), n' represents an integer from 4 to 10; in (Rf-5), n is an integer from 1 to 8, n'' is an integer from 0 to 7, m is an integer from 0 to 7, where n + n'' × m represents an integer from 2 to 8, J 1 represents a hydrogen atom, fluorine atom, hydroxyl group, amino group, carboxyl group, or (meth)acryloyloxy group, and in (Rf-6), n is an integer from 0 to 8, n'' is an integer from 0 to 4, m is an integer from 0 to 8, where n + n'' × m represents an integer from 2 to 8.

[0051] In the above equations (Rf-1), (Rf-2), and (Rf-3), n independently represents an integer from 2 to 8, but from the viewpoint of surface localization effect, it is preferable that n represents an integer from 4 to 8. In (Rf-4) above, n' represents an integer from 4 to 10, but from the viewpoint of surface localization effect, it is preferable that n represents an integer from 5 to 10. In (Rf-5) above, n is an integer from 1 to 8, n'' is an integer from 0 to 7, and m is an integer from 0 to 7, where n+n''×m represents an integer from 2 to 8. However, from the viewpoint of surface localization effect, it is preferable that n is an integer from 2 to 8, n'' is an integer from 1 to 7, and m is an integer from 1 to 7, and among these, it is preferable that n+n''×m represents an integer from 3 to 8. In (Rf-6) above, n is an integer from 0 to 8, n'' is an integer from 0 to 4, and m is an integer from 0 to 8, where n+n''×m represents an integer from 2 to 8. However, from the viewpoint of surface localization effect, it is preferable that n is an integer from 2 to 8, n'' is an integer from 1 to 7, and m is an integer from 1 to 7, and among these, it is preferable that n+n''×m represents an integer from 3 to 8.

[0052] In the above (Rf-5), J 1 This represents a hydrogen atom, a fluorine atom, a hydroxyl group, an amino group, a carboxyl group, or a (meth)acryloyloxy group. 1 It is preferably a hydrogen atom or a fluorine atom, more preferably a fluorine atom, but may also be a hydroxyl group, an amino group, a carboxyl group, or a (meth)acryloyloxy group. 1 If such a reactive group is present, it may be used, for example, to bond other components in an adhesive composition with a gas generating agent. Even when preparing the compound of general formula (2), if gas generating units are not introduced at both ends but only at one end, the compound may still have the structure of general formula (1) and may have reactive groups such as hydroxyl groups, amino groups, carboxyl groups, or (meth)acryloyloxy groups at the end.

[0053] Q 1 In particular, it is preferably one monovalent fluorinated aliphatic hydrocarbon group represented by (Rf-1) or (Rf-5), more preferably one monovalent fluorinated aliphatic hydrocarbon group represented by (Rf-1) or (Rf-5), and even more preferably one monovalent fluorinated aliphatic hydrocarbon group represented by (Rf-1).

[0054] Meanwhile, Q 1 and Q 2In the case of, the organopolysiloxane group has a siloxane bond -(O-Si) a -(where a is the number of repetitions) in the main chain and refers to a group containing a hydrocarbon group in at least a part of the side chain.

[0055] Q 1 and Q 2 As the organopolysiloxane group in, from the viewpoint of the effect of surface localization, Q 1 includes a monovalent organopolysiloxane group represented by the following (Si-1), and Q 2 includes a divalent organopolysiloxane group represented by the following (Si-2).

[0056] [Chemical formula] (In formulas (Si-1) and (Si-2), R 11 each independently represents a monovalent hydrocarbon group having 1 to 20 carbon atoms which may have a substituent, a hydrogen atom, a hydroxyl group, an alkoxy group having 1 to 20 carbon atoms, or a group represented by the following general formula (Si-3), and J 2 represents a monovalent hydrocarbon group having 1 to 20 carbon atoms which may have a substituent, a hydrogen atom, a hydroxyl group, an alkoxy group having 1 to 20 carbon atoms, an amino group, a carboxy group, or a (meth)acryloyloxy group. a each independently represents a number from 1 to 100.)

[0057] [Chemical formula] (In formula (Si-3), R 12 each independently represents a monovalent hydrocarbon group having 1 to 20 carbon atoms which may have a substituent, a hydrogen atom, a hydroxyl group, or an alkoxy group having 1 to 20 carbon atoms, and b represents a number from 0 to 100.)

[0058] R 11 and R 12 The monovalent hydrocarbon group having 1 to 20 carbon atoms which may have a substituent in may be the same as the hydrocarbon group having 1 to 20 carbon atoms which may have a substituent in the said R 2 R11 and R 12 Examples of the monovalent hydrocarbon group having 1 to 20 carbon atoms which may have a substituent in R include, among others, a hydrocarbon group having 1 to 10 carbon atoms which may have a substituent, and specifically include an alkyl group such as methyl group, ethyl group, propyl group, butyl group, a cycloalkyl group such as cyclohexyl group, an aryl group such as phenyl group, tolyl group, an aralkyl group such as benzyl group, phenethyl group, or a hydroxypropyl group, cyanoethyl group, 1-chloropropyl group, 3,3,3-trifluoropropyl group, etc. obtained by substituting part or all of the hydrogen atoms bonded to the carbon atoms of these groups with a hydroxy group, cyano group, halogen atom, etc. R 11 and R 12 Examples of the alkoxy group having 1 to 20 carbon atoms in R include an alkoxy group having 1 to 10 carbon atoms, and specifically include methoxy group, ethoxy group, propoxy group, butoxy group, etc. R 11 and R 12 From the viewpoint of solubility in an organic solvent, an alkyl group, aryl group having 1 to 10 carbon atoms, or a group represented by the general formula (Si-3) is preferable, and an alkyl group having 1 to 5 carbon atoms is more preferable. R 12 is preferably an alkyl group or aryl group having 1 to 10 carbon atoms, and more preferably an alkyl group having 1 to 5 carbon atoms.

[0059] J 2 represents a monovalent hydrocarbon group having 1 to 20 carbon atoms which may have a substituent, a hydrogen atom, a hydroxy group, an alkoxy group having 1 to 20 carbon atoms, an amino group, a carboxy group, or a (meth)acryloyloxy group. J 2 is preferably a monovalent hydrocarbon group having 1 to 20 carbon atoms which may have a substituent, a hydrogen atom, or an alkoxy group having 1 to 20 carbon atoms, but may also be a hydroxy group, an amino group, a carboxy group, or a (meth)acryloyloxy group. J 2 When J has such a reactive group, for example, it may be used for bonding between other components in the adhesive composition and the gas generating agent. Even when preparing the compound of general formula (2), if gas generating units are not introduced at both ends but only at one end, the compound may still have the structure of general formula (1) and may have reactive groups such as hydroxyl groups, amino groups, carboxyl groups, or (meth)acryloyloxy groups at the end.

[0060] In the general formulas (Si-1) and (Si-2) above, a represents a number from 1 to 100. Since a may have a distribution, it may be an average value. From the viewpoint of nitrogen content in one molecule, a preferably represents a number from 1 to 50, more preferably a number from 5 to 45, and even more preferably a number from 10 to 40. Furthermore, in the general formula (Si-3) above, b represents a number from 0 to 100. Since b may also have a distribution, it may be an average value. Preferably, b represents a number from 0 to 40, and more preferably, a number from 0 to 30.

[0061] When used in semiconductor-related and display-related fields, Q is preferred due to its low risk of contamination. 1 Q is preferably a monovalent fluorinated aliphatic hydrocarbon group in which the number of carbon atoms directly bonded to the fluorine atom is 2 to 8, and which may contain an ether bond (-O-) in the carbon chain and may have substituents. 2 It is preferable that the fluorinated aliphatic hydrocarbon group is a divalent fluorinated aliphatic hydrocarbon group in which the number of carbon atoms directly bonded to the fluorine atom is 2 to 8, and which may contain an ether bond (-O-) in the carbon chain.

[0062] On the other hand, in general formulas (1) and (2), L independently represents a direct bond or a divalent linking group. In general formulas (1) and (2), L represents a portion that links the gas generating portion with the specific fluorinated aliphatic hydrocarbon group or organopolysiloxane group, and is not particularly limited as long as it is a linking portion that can bond the specific fluorinated aliphatic hydrocarbon group or organopolysiloxane group to the gas generating portion. A direct bond means that L does not have an atom, that is, the carbon atom of A in general formulas (1) and (2) and Q 1 Or Q 2This means that a carbon or silicon atom is bonded to another atom without the involvement of any other atoms.

[0063] In general formulas (1) and (2), L can be independently, for example, a direct bond, or one or more C1-C22 hydrocarbon groups selected from the group consisting of -SCH2CH2COO-, -SCH2CH(CH3)COO-, -SCH2CH(OH)CH2-, -OCH2CH(OH)CH2-, -SCH(CH3)O-, -OCH(CH3)O-, -COO-, -CONH-, -COS-, -SO2NH-, or -O- and -S-, and which may have a hydroxyl group substituted, or a combination thereof. The orientation of the bond in L is arbitrary. That is, when L is -SCH2CH2COO-, S is bonded to the carbon atom of A, and O is bonded to Q. 1 Or Q 2 When S is bonded to a carbon or silicon atom, and when S is bonded to the Q 1 Or Q 2 This includes cases where O is bonded to a carbon or silicon atom of A, and O is bonded to a carbon atom of A.

[0064] Examples of the hydrocarbon groups having 1 to 22 carbon atoms include methylene groups, ethylene groups, propylene groups (trimethylene groups, methylethylene groups), butylene groups (tetramethylene groups, methylpropylene groups), alkylene groups such as pentamethylene groups, hexamethylene groups, octamethylene groups, and cyclohexylene groups, arylene groups such as phenylene groups, and combinations of two or more of these groups (alkylene arylene groups).

[0065] Examples of the combinations of L in general formulas (1) and (2) include: (L1):-SCH2CH2COO-(C j H 2j )-, (L2):-SCH2CH2COO-(C j H 2j )-O-(C k H 2k )-, (L3):-SCH2CH2COO-(Cj H 2j )-NHCO-(C k H 2k )-, (L4):-SCH2CH2CO-OCH2CH(OH)CH2O-(C j H 2j )-, (L5):-SCH2CH2CO-OCH2CH(OH)-(C j H 2j )-, (L6):-SCH2CH2COO-(C j H 2j )-NHCO-CH{CH2O-(C k H 2k )-Rf}-CH2O-(C l H 2l )-, (L7):-SCH2CH2COO-CH{CH2O-(C j H 2j )-Rf}-CH2O-(C k H 2k )-, (L8):-SCH2CH2COO-(C j H 2j )-N(C k H 2k+1 )SO2-, (L9):-SCH2CH2CON(C j H 2j+1 )-(C k H 2k )-, (L10):-SCH2CH2COO-(C j H 2j )-N(C k H 2k+1 )CO-, (L11):-OCH(CH3)O-(C j H 2j Examples include, but are not limited to, )-etc. (where j, k, and l each independently represent integers from 1 to 8, and Rf is any one monovalent fluorinated aliphatic hydrocarbon group represented by the general formulas (Rf-1) to (Rf-3) above). The aforementioned j, k, and l each preferably represent an integer between 2 and 6, and more preferably represent an integer between 2 and 4.

[0066] The gas generating agent of the present invention is preferably one that, from the viewpoint of foaming properties in the ultraviolet region, is represented by at least one of the following (1-1) and (2-1), has a maximum molar extinction coefficient of 7000 or more at wavelengths of 240 to 450 nm, and generates gas upon light irradiation.

[0067] [ka] (In general formulas (1-1) and (2-1), R 1 , L, Q 1 , and Q 2 These terms independently represent the same things as general formulas (1) and (2).

[0068] Examples of compounds represented by the general formula (1-1) include, but are not limited to, the following compounds. For example, A may be (a-1-1) to (a-1-15), L may be (L1) to (L11), Q 1 Any combination of (Rf-1) to (Rf-5) and (Si-3) can be listed as examples.

[0069] [Table 1]

[0070] Examples of compounds represented by the general formula (2-1) include, but are not limited to, the following compounds. For example, A may be (a-1-1) to (a-1-15), L may be (L1) to (L11), Q 2 Any combination of (Rf-6) and (Si-2) can be cited as an example.

[0071] [Table 2]

[0072] [Characteristics of gas generating agents] The gas generating agent of this disclosure has a maximum molar extinction coefficient of 7000 or more at wavelengths of 240 to 450 nm, thereby enabling efficient gas generation by light irradiation. From the viewpoint of efficiently generating gas and improving ease of peeling, the gas generating agent of this disclosure preferably has a maximum molar extinction coefficient of 8000 or more at wavelengths of 240 to 450 nm, and more preferably has a maximum molar extinction coefficient of 9000 or more. The molar extinction coefficient as defined herein refers to the value obtained by dissolving the gas generating agent in ethyl acetate to a concentration of 0.1 mM, measuring the absorption spectrum in the wavelength range of 230 nm to 800 nm using a UV-Vis spectrophotometer (for example, a UV2700 UV-Vis spectrophotometer manufactured by Shimadzu Corporation), and calculating the value using the absorbance in the obtained absorption spectrum according to the following formula. ε = A / c × d (In the formula, ε represents the molar extinction coefficient, A represents the absorbance, c represents the molar concentration, and d represents the cell thickness.) If the gas generating agent does not dissolve in ethyl acetate at a concentration of 0.1 mM, an appropriate solvent that does not cause problems with the reproducibility of the molar extinction coefficient of the gas generating agent should be selected and dissolved at a concentration of 0.1 mM, and the same procedure as described above should be followed. Examples of solvents that do not cause problems with the reproducibility of the molar extinction coefficient of the gas generating agent include organic solvents that do not have an absorption spectrum in the wavelength range of 230 nm to 800 nm and that do not react with the gas generating agent. Specific examples include acetonitrile and dichloromethane. In this specification, a maximum molar extinction coefficient of 7000 or more at wavelengths of 240 to 450 nm means that the molar extinction coefficient at any wavelength between 240 and 450 nm is 7000 or more, and there does not need to be a peak between 240 and 450 nm.

[0073] The molecular weight or mass-average molecular weight Mw of the gas generating agent of this disclosure is not particularly limited, but is preferably 200 to 2000 and more preferably 300 to 1000 from the viewpoint of the nitrogen atom content in one molecule. Here, the molecular weight of the gas generating agent can be determined by liquid chromatography-mass spectrometry (LC-MS). Furthermore, if the gas generating agent contains an organopolysiloxane group, it may be identified by its mass-average molecular weight, which can be determined as a standard polystyrene equivalent value by gel permeation chromatography (GPC).

[0074] [Method for manufacturing gas generating agent] The method for producing the gas generating agent of the present disclosure is not particularly limited, and for example, the gas generating agent of the present disclosure can be obtained by reacting a gas generating unit having a reactive group with a compound having a reactive group that reacts with the reactive group of the gas generating unit to form a bond and a fluorinated aliphatic hydrocarbon group or an organopolysiloxane group. Examples of combinations of reactive groups include, but are not limited to, a thiol group and a (meth)acryloyloxy group, a thiol group and an epoxy group, a thiol group and a vinyl ether group, a hydroxyl group and a vinyl ether group, a hydroxyl group and an epoxy group, a hydroxyl group and an isocyanate group, an amino group and a sulfonyl chloride group, a carboxyl group and an epoxy group, etc. In each combination, either group may be the reactive group on the gas generation side, and the other may be the reactive group on the compound side having a fluorinated aliphatic hydrocarbon group or an organopolysiloxane group.

[0075] As a gas generating unit having a reactive group, it is possible to synthesize it by referring to, for example, Russian Journal of General Chemistry (2017), 87(4), pp. 731-738. For example, by reacting an isothiocyanate derivative (RN=C=S, where R is an aromatic group having 3 to 20 carbon atoms) with sodium azide, a tetrazole compound in which a thiol group and R (an aromatic group having 3 to 20 carbon atoms) are substituted can be synthesized. Also, by referring to Japanese Patent Publication No. 59-196860, a naphthoquinone diazide compound having a sulfonic acid chloride group can be synthesized. Furthermore, by referring to Shandong Huagong, Volume:37, Issue:3, Pages:7-9, Journal, 2008, an azo compound having a carboxyl group can be synthesized by reacting sodium cyanide with 4-oxopentanoic acid and hydrazine monohydrate. Alternatively, a commercially available gas generator containing a reactive group may be appropriately selected and used. Furthermore, compounds having a reactive group and a fluorinated aliphatic hydrocarbon group or an organopolysiloxane group can be synthesized, for example, by reacting a naphthoquinone diazide compound having a sulfonic acid chloride group with an organopolysiloxane compound having an amino group, as described in Japanese Patent Publication No. 6137289, ChemistrySelect, Volume:3, Issue:15, Pages:4129-4132, Journal, 2018. Also, compounds having a fluorinated aliphatic hydrocarbon group can be synthesized by reacting a vinyl ether group having a fluorinated aliphatic hydrocarbon group with an azo compound having a carboxyl group, as described in Macromolecules, Volume:37, Issue:18, Pages:6673-6675, Journal, 2004. Alternatively, commercially available compounds having a reactive group and a fluorinated aliphatic hydrocarbon group or an organopolysiloxane group may be appropriately selected and used.

[0076] [Uses of gas generating agents] The gas generating agent of this disclosure has a gas generating portion having the specific structure described above, and therefore has the specific fluorinated aliphatic hydrocarbon group or the specific organopolysiloxane group described above, and thus is easily localized on the surface. For this reason, as described later, the gas generating agent of this disclosure is suitably used in adhesive materials for the purpose of high adhesion and easy peelability, in order to improve peelability.

[0077] B. Adhesive composition An adhesive composition according to one embodiment of the present disclosure contains an adhesive component and the gas generating agent of the present disclosure. Since the adhesive composition of one embodiment of the present disclosure contains the gas generating agent of the present disclosure, the amount of gas generated on the surface of the adhesive layer is efficiently increased due to the action of the gas generating agent which tends to localize on the surface as described above. Therefore, it is possible to form an adhesive layer that has good adhesive strength when adhesive strength is required, and when adhesive strength that peels the adhesive layer from the adherend is no longer required, it is possible to form an adhesive layer that has excellent peelability from the adherend.

[0078] [Adhesive components] The adhesive component is not particularly limited and may be either a non-photocurable adhesive component or a photocurable adhesive component. If the adhesive component is a non-photocurable adhesive component, light irradiation generates gas from the gas generating agent of this disclosure, and the generated gas generates peeling stress, and the adhesion area with the adherend decreases, causing peeling. When the adhesive component is a photocurable adhesive component, peeling becomes easier due to the synergistic effect of the reduction in the adhesion area with the adherend caused by the generation of gas from the gas generating agent of this disclosure when irradiated with light, and the decrease in the adhesive strength of the adhesive component itself due to photocuring. For this reason, it is preferable that the adhesive component be photocurable.

[0079] The aforementioned photocurable adhesive component is not particularly limited, but examples include one that contains an adhesive, a photocurable component, and a photoinitiator. The photocurable adhesive component used in the adhesive composition of one embodiment of this disclosure may be (i) a composition containing an adhesive, a photocurable polyfunctional compound, and a photoinitiator, or (ii) a composition containing an adhesive having two or more photocurable functional groups in one molecule, and a photoinitiator. In particular, the photocurable adhesive component is preferably (i) a composition containing an adhesive, a photocurable polyfunctional compound, and a photoinitiator, as it allows for easy adjustment of the adhesive strength. In the case of (i), the adhesive may have photocurable functional groups.

[0080] (Adhesive) The adhesive is not particularly limited and includes, for example, rubber-based adhesives, acrylic-based adhesives, vinyl alkyl ether-based adhesives, silicone-based adhesives, polyester-based adhesives, polyamide-based adhesives, urethane-based adhesives, styrene-dieneblock copolymer-based adhesives, and the like.

[0081] As for the adhesive, it is preferable that it be a (meth)acrylic acid ester polymer, referred to as an acrylic adhesive, in terms of compatibility with the photocurable component and the ability to adjust the adhesive strength. As the (meth)acrylic acid ester polymer, it is preferable to use a (meth)acrylic acid ester copolymer obtained by copolymerizing a constituent unit derived from an alkyl (meth)acrylic acid ester monomer with 1 to 20 carbon atoms in a linear or branched alkyl group used as an acrylic adhesive with other monomers as needed. Among the (meth)acrylic acid ester polymers, it is preferable that the (meth)acrylic acid ester copolymer has constituent units derived from (meth)acrylic acid alkyl ester monomers with 1 to 20 carbon atoms in a linear or branched alkyl group, and constituent units derived from monomers containing crosslinkable groups. This (meth)acrylic acid ester copolymer can be crosslinked with thermal crosslinking agents, etc., described later, by utilizing the crosslinkable groups introduced into the molecule of the (meth)acrylic acid ester polymer, thereby improving the cohesive strength of the adhesive composition and obtaining an adhesive layer with a good balance between easy peelability and durability under specified conditions.

[0082] Examples of alkyl (meth)acrylate monomers having 1 to 20 carbon atoms in a linear or branched alkyl group include one or more of the following: methyl (meth)acrylate, ethyl (meth)acrylate, propyl (meth)acrylate, n-butyl (meth)acrylate, n-pentyl (meth)acrylate, n-hexyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, n-octyl (meth)acrylate, isooctyl (meth)acrylate, n-nonyl (meth)acrylate, isononyl (meth)acrylate, n-decyl (meth)acrylate, isodecyl (meth)acrylate, n-dodecyl (meth)acrylate, n-tridecyl (meth)acrylate, n-tetradecyl (meth)acrylate, n-hexadecyl (meth)acrylate, n-octadecyl (meth)acrylate, etc. In particular, alkyl (meth)acrylates having a linear or branched alkyl group with 4 to 14 carbon atoms are preferred, and alkyl (meth)acrylates having a linear or branched alkyl group with 7 to 13 carbon atoms are even more preferred, from the viewpoint of exhibiting wettability and tackiness to the adherend.

[0083] Examples of crosslinkable groups in (meth)acrylic acid ester polymers include hydroxyl groups, epoxy groups, isocyanate groups, carboxyl groups, and amino groups. From the viewpoint of the polymer's stability during polymerization and storage, it is preferable that the polymer contains monomer-derived structural units that include one or more selected from the group consisting of hydroxyl groups, epoxy groups, carboxyl groups, and amino groups. It is preferable that the polymer contains monomer-derived structural units because they offer high stability and excellent reactivity with thermal crosslinking agents.

[0084] Examples of monomers that derive structural units from hydroxyl group-containing monomers include 2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, and glycerin mono(meth)acrylate. Examples of monomers that derive structural units from epoxy group-containing monomers include glycidyl (meth)acrylate and 3,4-epoxycyclohexylmethyl (meth)acrylate. Examples of monomers that derive structural units from isocyanate group-containing monomers include 2-(meth)acryloyloxyethyl isocyanate and its alkylene oxide adducts. Examples of monomers that derive structural units from amino group-containing monomers include ethylaminoethyl (meth)acrylate and dimethylaminoethyl (meth)acrylate. Examples of monomers that derive structural units from carboxyl group-containing monomers include (meth)acrylic acid, vinylbenzoic acid, maleic acid, and ω-carboxy-polycaprolactone mono(meth)acrylate.

[0085] Furthermore, the (meth)acrylic acid ester polymer may also have a photocurable functional group in its side chain. The photocurable functional group is preferably one that has an ethylenically unsaturated bond, and is preferably a (meth)acryloyl group, vinyl group, allyl group, etc. As a method for introducing a photocurable functional group into the side chain of a (meth)acrylic acid ester polymer, any conventionally known manufacturing method can be appropriately selected and used. For example, photocurable functional groups can be added by reacting a (meth)acrylic acid ester polymer having a carboxyl group with glycidyl (meth)acrylate, reacting a (meth)acrylic acid ester polymer having an isocyanate group with hydroxyethyl (meth)acrylate, or reacting a (meth)acrylic acid ester polymer having a hydroxyl group with 2-isocyanatoethyl (meth)acrylate.

[0086] Furthermore, the (meth)acrylic acid ester polymer may also contain other monomer-derived structural units within the range that it functions as an acrylic adhesive. Other monomers that can be used include, for example, rigid monomers such as cyclohexyl methacrylate, benzyl methacrylate, and adamantyl methacrylate.

[0087] Since (meth)acrylic acid ester monomers are the main components of (meth)acrylic acid ester polymers, it is generally preferable that their content be 50% by mass or more relative to the total monomer components (100% by mass). In particular, the content of the alkyl (meth)acrylate monomer is, for example, 50% by mass or more, may be 60% by mass or more, may be 80% by mass or more, or may be 90% by mass or more, relative to the total monomer components. On the other hand, the content of the alkyl (meth)acrylate monomer is, for example, 99.5% by mass or less, may be 99% by mass or less, or may be 98% by mass or less, relative to the total monomer components.

[0088] The content of the crosslinkable group-containing monomer can be appropriately selected from the viewpoint of balancing adhesive strength and peeling strength, but may be, for example, 0.5% by mass or more, 1% by mass or more, or 2% by mass or more, relative to the total monomer components. On the other hand, the content of the crosslinkable group-containing monomer may be, for example, 15% by mass or less, 13% by mass or less, or 10% by mass or less, relative to the total monomer components.

[0089] The content of other monomers in the (meth)acrylic acid ester polymer can be appropriately selected based on the balance between adhesiveness and peelability and the desired performance, but examples include 0% by mass or more and 49.5% by mass or less, and it may also be 39% by mass or less, or 18% by mass or less.

[0090] The mass-average molecular weight of the (meth)acrylic acid ester polymer is preferably 100,000 to 5,000,000, more preferably 200,000 to 4,000,000, even more preferably 300,000 to 3,000,000, and even more preferably 400,000 to 1,000,000, from the viewpoint of good adhesion and peelability. If the mass-average molecular weight is less than 100,000, the cohesive force may be weak, which may result in adhesive residue on the surface of the adherend after peeling, or the adhesive effect may not be obtained. Also, if the mass-average molecular weight exceeds 5,000,000, the wettability of the surface of the adherend after peeling of the adhesive layer may be insufficient. The mass-average molecular weight of (meth)acrylic acid ester polymers can be determined as a standard polystyrene equivalent value by gel permeation chromatography (GPC).

[0091] Furthermore, as the (meth)acrylic acid ester polymer, commercially available acrylic adhesives may be used. For example, SK Dyne 2971 (manufactured by Soken Chemical), SK Dyne 2975 (manufactured by Soken Chemical), SK Dyne 1811L (manufactured by Soken Chemical), SK Dyne 2950 (manufactured by Soken Chemical), SK Dyne 2094 (manufactured by Soken Chemical), and Olivine EG-654 (manufactured by Toyo Chem) can be suitably used.

[0092] The adhesive can be used individually or in combination of two or more types. The amount of adhesive may be, for example, 20% by mass or more, or 30% by mass or more, relative to the solid content of the adhesive composition, from the viewpoint of the adhesive strength effect. Furthermore, the amount of adhesive may be, for example, 80% by mass or less, or 70% by mass or less, relative to the solid content of the adhesive composition, from the viewpoint of re-peelability of the adhesive layer. In this specification, "solids" refers to all components other than the solvent.

[0093] (Photocurable polyfunctional compound) It is preferable to include a photocurable polyfunctional compound as a photocurable component. The photocurable polyfunctional compound is a monomer, oligomer, or polymer containing two or more photocurable groups per molecule. By including a photocurable polyfunctional compound, three-dimensional crosslinking is possible. Furthermore, if the (meth)acrylic acid ester polymer is photocurable, it can react with the (meth)acrylic acid ester polymer to increase its molecular weight or to undergo three-dimensional crosslinking. By including a photocurable component, the adhesion and cohesiveness of the substrate when an adhesive layer is formed can be easily controlled to a desired range.

[0094] Examples of photocurable polyfunctional compounds include 1,4-butanediol di(meth)acrylate, 1,6-hexanediol di(meth)acrylate, neopentyl glycol di(meth)acrylate, polyethylene glycol di(meth)acrylate, neopentyl glycol adipate di(meth)acrylate, hydroxypivalate neopentyl glycol di(meth)acrylate, dicyclopentanyl di(meth)acrylate, and caprolactone-modified dicyclopentenyl di(meth)acrylate. Acrylate, ethylene oxide-modified phosphate di(meth)acrylate, di(meth)acryloxyethyl isocyanurate, allylated cyclohexyl di(meth)acrylate, tricyclodecane dimethanol di(meth)acrylate, dimethylol dicyclopentane di(meth)acrylate, ethylene oxide-modified hexahydrophthalate di(meth)acrylate, neopentyl glycol-modified trimethylolpropane di(meth)acrylate, adamantane di(meth)acrylate, 9,9-Bis[4-(2-acryloyloxyethoxy)phenyl]fluorene and other bifunctional polyfunctional (meth)acrylate monomers, isocyanurate ethylene oxide modified triacrylate, trimethylolpropane tri(meth)acrylate, dipentaerythritol tri(meth)acrylate, propionic acid modified dipentaerythritol tri(meth)acrylate, pentaerythritol tri(meth)acrylate, propylene oxide modified trimethylolpropane tri(meth)acrylate, trifunctional polyfunctional (meth)acrylate monomers such as tris(meth)acryloxyethyl isocyanurate, diglycerin tetra(meth) Preferably, oligomers with molecular weights ranging from several hundred to several thousand, having several (meth)acryloyl groups within the molecule, can be used. These include tetrafunctional (meth)acrylate monomers such as acrylate, pentaerythritol tetra(meth)acrylate, pentafunctional polyfunctional (meth)acrylate monomers such as propionic acid-modified dipentaerythritol penta(meth)acrylate, hexafunctional polyfunctional (meth)acrylate monomers such as dipentaerythritol hexa(meth)acrylate and caprolactone-modified dipentaerythritol hexa(meth)acrylate, and oligomers with molecular weights ranging from several hundred to several thousand, referred to as urethane (meth)acrylate, polyester (meth)acrylate, and epoxy (meth)acrylate.

[0095] As for photocurable polyfunctional compounds, it is preferable to use oligomers with molecular weights ranging from several hundred to several thousand, which have several (meth)acryloyl groups in their molecules, such as urethane (meth)acrylate, polyester (meth)acrylate, and epoxy (meth)acrylate, in terms of the balance between adhesiveness and peelability.

[0096] Photocurable polyfunctional compounds can be used individually or in combination of two or more. When using a photocurable polyfunctional compound, the content of the photocurable polyfunctional compound may be, for example, 10 parts by mass or more, 20 parts by mass or more, or 50 parts by mass or more, per 100 parts by mass of the adhesive such as the (meth)acrylic acid ester polymer, while on the other hand, it may be 300 parts by mass or less, 200 parts by mass or less, or 150 parts by mass or less. If the amount of photocurable polyfunctional compound is too low, the additive effect may not be observed. On the other hand, if the amount of photocurable polyfunctional compound is too high, the storage stability, substrate adhesion, tackiness, or peelability properties of the adhesive composition may be significantly reduced.

[0097] The total content of the adhesive and the photocurable polyfunctional compound may be, for example, 10% by mass or more, or 20% by mass or more, relative to the solid content of the adhesive composition, from the viewpoint of balancing the peeling force after light irradiation. Furthermore, the total content of the adhesive and the photocurable polyfunctional compound may be, for example, 70% by mass or less, or 60% by mass or less, relative to the solid content of the adhesive composition, from the viewpoint of adhesive strength and suppression of contamination of the adherend.

[0098] (Photoinitiator) As a photoinitiator, any compound capable of generating radicals when irradiated with a predetermined amount of light such as ultraviolet light can be used, but for example, bensoin, benzoin methyl ether, benzoin ethyl ether, benzoin isopropyl ether, benzoin-n-butyl ether, benzoin isobutyl ether, acetophenone, dimethylaminoacetophenone, 2,2-dimethoxy-2-phenylacetophenone, 2,2-diethoxy-2-phenylacetophenone, 2-hydroxy-2-methyl-1-phenylpropan-1-one, 1-hydroxycyclohexylphenyl ketone, 2-methyl-1-[4-(methylthio)phenyl]-2-morpholino-propan-1-one, 4-(2-hydroxyethoxy)phenyl-2-(hydroxy Examples include c-2-propyl) ketone, benzophenone, p-phenylbenzophenone, 4,4'-diethylaminobenzophenone, dichlorobenzophenone, 2-methylanthraquinone, 2-ethylanthraquinone, 2-tert-butylanthraquinone, 2-aminoanthraquinone, 2-methylthioxanthone, 2-ethylthioxanthone, 2-chlorothioxanthone, 2,4-dimethylthioxanthone, 2,4-diethylthioxanthone, benzyldimethyl ketal, acetophenone dimethyl ketal, p-dimethylaminobenzoic acid ester, oligo[2-hydroxy-2-methyl-1[4-(1-methylvinyl)phenyl]propanone], 2,4,6-trimethylbenzoyl-diphenyl-phosphine oxide, etc. In particular, at least one selected from the group consisting of acylphosphine oxide-based initiators, α-aminoalkylphenone-based initiators, α-hydroxyketone-based initiators, and oxime ester-based initiators is preferred because it hardens to the interior of the coating film and improves durability. The photoinitiator can be used individually or in combination of two or more types.

[0099] The amount of photoinitiator may be, for example, 0.5% by mass or more, or 1.0% by mass or more, relative to the solid content of the adhesive composition, in order to sufficiently cure the adhesive composition. Furthermore, the amount of photoinitiator may be, for example, 10.0% by mass or less, or 5.0% by mass or less, relative to the solid content of the adhesive composition, in order to balance the adhesive strength and peeling strength.

[0100] (Thermal crosslinking agent) The adhesive composition of this disclosure preferably further contains a thermal crosslinking agent. A thermal crosslinking agent is a compound that promotes a crosslinking reaction through the action of heat. By including a thermal crosslinking agent in the adhesive composition of this disclosure, it is possible to react with the crosslinking groups contained in the adhesive to eliminate the fluidity of the adhesive composition itself after film formation, or to adjust the adhesive strength or peeling strength before light irradiation.

[0101] Examples of thermal crosslinking agents include isocyanate-based crosslinking agents, epoxy-based crosslinking agents, melamine-based crosslinking agents, aziridine-based crosslinking agents, and metal chelate-based crosslinking agents. Among these, isocyanate-based crosslinking agents and epoxy-based crosslinking agents are preferred because they readily exhibit the effects of this disclosure.

[0102] Examples of isocyanate crosslinking agents 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; trimethylolpropane / tolylene diisocyanate trimer adduct (product name "Coronate L," manufactured by Nippon Polyurethane Industry Co., Ltd.); trimethylolpropane / hexamethylene diisocyanate trimer adduct (product name "Coronate HL," manufactured by Nippon Polyurethane Industry Co., Ltd.); and isocyanurate derivatives of hexamethylene diisocyanate (product name "Coronate HX," manufactured by Nippon Polyurethane Industry Co., Ltd.).

[0103] Examples of epoxy crosslinking agents include bisphenol A, epichlorohydrin-type epoxy resins, ethylene glycidyl ether, polyethylene glycol diglycidyl ether, glycerin diglycidyl ether, glycerin triglycidyl ether, 1,6-hexanediol glycidyl ether, trimethylolpropane triglycidyl ether, diglycidylaniline, diamine glycidylamine, N,N,N',N'-tetraglycidyl-m-xylenediamine (trade name "TETRAD-X", manufactured by Mitsubishi Gas Chemical Co., Ltd.), and 1,3-bis(N,N-diglycidylaminomethyl)cyclohexane (trade name "TETRAD-C", manufactured by Mitsubishi Gas Chemical Co., Ltd.).

[0104] The thermal crosslinking agent can be used individually or in combination of two or more types. The content of the thermal crosslinking agent can be adjusted as appropriate based on the balance between tackiness and peelability, but in order to obtain the above effects, it may be, for example, 1.0% by mass or more, or 2.0% by mass or more, relative to the solid content of the adhesive composition. Furthermore, in terms of tackiness before energy irradiation, the content of the thermal crosslinking agent may be, for example, 10.0% by mass or less, or 8.0% by mass or less, relative to the solid content of the adhesive composition.

[0105] [Gas Generating Agent of This Disclosure] The adhesive composition of this disclosure contains the gas generating agent of this disclosure. Since the gas generating agent of this disclosure tends to localize on the surface of the adhesive material, it is possible to efficiently increase the amount of gas generated on the surface of the adhesive material without increasing the content of the gas generating agent in the adhesive composition, thereby making it easier to suppress a decrease in the adhesive strength and clouding of the adhesive material.

[0106] The content of the gas generating agent described herein may be, for example, 2% by mass or more, or 3% by mass or more, relative to the solid content of the adhesive composition, in order to effectively reduce the peeling force during peeling. Furthermore, the content of the gas generating agent described herein may be, for example, 40% by mass or less, or 30% by mass or less, relative to the solid content of the adhesive composition, in order to suppress a decrease in the adhesive strength and clouding of the adhesive material. By suppressing clouding of the adhesive material and achieving high transparency, it becomes possible to perform precise visual defect inspections using cameras, etc., through the adhesive layer, and the adhesive layer can be suitably used in process-removable adhesive sheets, thus expanding its range of applications.

[0107] [solvent] The adhesive composition of this disclosure may further contain a solvent. By including a solvent, the applicability to substrates and the mixability of the constituent components can be improved. The solvent can be appropriately selected from among solvents that do not react with the components in the composition but can dissolve or disperse them. Examples of solvents include esters, aromatic hydrocarbons, ketones, and ethers. More specifically, examples include one or more combinations of methyl acetate, ethyl acetate, n-butyl acetate, i-butyl acetate, benzene, toluene, xylene, acetone, cyclohexane, cyclohexanone, methyl ethyl ketone, and tetrahydrofuran, due to their good solubility in (meth)acrylic acid ester polymers and ease of handling.

[0108] Furthermore, the solvent content may be adjusted as appropriate from the standpoint of applicability to the substrate and mixability of the compounded components, but for example, it can be 5% to 40% by mass relative to the total amount (100% by mass) of the adhesive composition including the solvent.

[0109] [Optional addition ingredients] The adhesive compositions of this disclosure may further contain various additives as necessary, to the extent that the purpose of this disclosure is not impaired. Examples of additives include crosslinking accelerators, antioxidants, stabilizers, viscosity modifiers, tackifying resins, and organic or inorganic fillers. Examples of crosslinking accelerators include triethylamine-based, cobalt naphthenate-based, tin-based, zinc-based, titanium-based, and zirconium-based accelerators. When the crosslinking agent is an isocyanate-based crosslinking agent, it is particularly preferable to use zinc-based, titanium-based, and zirconium-based accelerators such as alkoxides, acylates, and complexes, or tin-based accelerators such as stannous chloride, tetra-n-butyltin, stannic chloride, trimethyltin hydroxide, dimethyl stannous chloride, and di-n-butyltin dilaurate. Other examples of antioxidants include phenolic antioxidants.

[0110] [Manufacturing of adhesive compositions] The method for producing the adhesive composition is not particularly limited. The adhesive composition can be obtained by adding the aforementioned components, and various additives as needed, in any order, and dissolving or dispersing them. The mixing of the components can be carried out using a mixer or kneader such as a dissolver, planetary mixer, or butterfly mixer.

[0111] [Uses of adhesive compositions] The uses of the adhesive composition disclosed herein are not particularly limited, but it can be suitably used in the adhesive layer of an adhesive sheet described later, and can be suitably used in the uses of the adhesive sheet described later. Furthermore, the adhesive composition of this disclosure can also be used for adhesive materials that are not in sheet form, and can be applied to temporary fixing adhesives, for example.

[0112] C. Adhesive sheet An adhesive sheet according to one embodiment of the present disclosure comprises an adhesive layer and a base material or release sheet on one side of the adhesive layer. The adhesive layer is an adhesive composition or a cured product thereof containing an adhesive component and the gas generating agent of the present disclosure, and the adhesive layer is an adhesive sheet having the property that its adhesive strength decreases from its initial adhesive strength upon light irradiation.

[0113] Figures 1 and 2 show schematic cross-sectional views of an example of the adhesive sheet of this disclosure. The adhesive sheet 10 of the present disclosure shown in Figure 1 comprises an adhesive layer 1 and a substrate or release sheet 2 disposed on one side of the adhesive layer 1. The adhesive sheet 10 of the present disclosure shown in Figure 2 comprises an adhesive layer 1, a substrate or release sheet 2 disposed on one side of the adhesive layer 1, and a release sheet 3 disposed on the side of the adhesive layer 1 opposite to the side of the substrate or release sheet 2. To facilitate handling, the adhesive sheet of the present disclosure may have the release sheet attached to the side of the adhesive layer opposite to the side of the substrate or release sheet 2 until it is bonded to an object.

[0114] [Adhesive layer] The adhesive layer in the adhesive sheet of this disclosure is an adhesive composition or a cured product thereof containing an adhesive component and the gas generating agent of this disclosure. The adhesive composition containing the adhesive component and the gas generating agent described herein may be the same as the adhesive composition described herein, so a detailed explanation is omitted here. If the adhesive composition contains a curable adhesive component, the adhesive layer in the adhesive sheet of this disclosure may be a cured product of the adhesive composition.

[0115] The thickness of the adhesive layer can be adjusted as appropriate depending on the purpose. From the viewpoint of the re-peelability of the adhesive layer, the thickness of the adhesive layer can be, for example, 100 μm or less, but it may also be 90 μm or less, or 80 μm or less. On the other hand, from the viewpoint of the development of adhesive strength, the thickness of the adhesive layer can be, for example, 10 μm or more, but it may also be 20 μm or more, or 40 μm or more.

[0116] The adhesive layer may have an initial adhesive strength before light irradiation, where the peeling force at a peeling speed of 300 mm / min and a peeling angle of 180 degrees relative to a glass plate (product name: alkali-free glass OA-11, manufactured by Nippon Electric Glass) is 0.1 N / 25 mm or more, or 0.2 N / 25 mm or more. On the other hand, the peeling force at a peeling angle of 180 degrees may be 30 N / 25 mm or less, or 20 N / 25 mm or less. Furthermore, the adhesive layer, as an adhesive strength after light irradiation, may have a peeling force of 0 N / 25 mm or more, or 0.01 N / 25 mm or more, when peeling from a glass plate (product name: alkali-free glass OA-11, manufactured by Nippon Electric Glass) at a peeling speed of 300 mm / min and a peeling angle of 180 degrees. On the other hand, the peeling force at the peeling angle of 180 degrees may be 1 N / 25 mm or less, or 0.1 N / 25 mm or less. The amount of light irradiation can be appropriately selected, for example, an exposure dose of 3000 mJ / cm². 2 Therefore, the adhesive strength after ultraviolet (UV) irradiation can be used as one indicator of adhesive strength after light irradiation. Generally speaking, the greater the peeling speed, the greater the peeling force.

[0117] The adhesive layer preferably has a total light transmittance of 80% or more, and more preferably 90% or more, before light irradiation. Furthermore, the adhesive layer preferably has a haze of 1.5% or less, and more preferably 1.0% or less, before light irradiation. Here, the total light transmittance of this disclosure can be measured in accordance with JIS K7361-1, for example, using a haze meter (e.g., HM150 manufactured by Murakami Color Technology Laboratory). The haze value can be measured in accordance with JIS K-7136, for example, using a haze meter (e.g., HM150 manufactured by Murakami Color Technology Laboratory). Within this range, the transparency of the adhesive layer is good, allowing for precise inspection and examination of the adherend using cameras, etc., while the adhesive sheet remains attached.

[0118] The presence of an adhesive component and the gas generating agent of this disclosure in the adhesive layer can be confirmed by sampling and analyzing the material from the adhesive layer. LC-MS is a preferred analytical method; other methods such as LC preparative analysis, GPC preparative analysis, NMR, IR, GC-MS, XPS, TOF-SIMS, and combinations thereof can also be applied.

[0119] [Base material] The substrate used in the adhesive sheet of this disclosure may be selected as appropriate and is not particularly limited. It is preferable to use a transparent substrate because it is preferable to reduce the adhesive strength from the initial adhesive strength of the adhesive layer by irradiating light from the substrate side of the adhesive sheet. The substrate used in the adhesive sheet of this disclosure preferably has a total light transmittance of 80% or more, and more preferably 90% or more. Furthermore, the substrate used in the adhesive sheet of this disclosure preferably has a haze of 1.5% or less, and more preferably 1.0% or less.

[0120] The substrate used in the adhesive sheet of this disclosure is preferably heat-resistant, and examples include polyester resins such as polyethylene terephthalate, polyethylene naphthalate, and polybutylene terephthalate, as well as films made of polyimide resin, polycarbonate resin, polystyrene resin, polyamide resin, polyetherimide resin, polyetherketone resin, polyphenylene sulfide resin, polyacrylate resin, polyester ether resin, polyamideimide resin, polymethyl methacrylate resin, and fluororesin. Polyethylene terephthalate is a particularly preferred substrate in terms of economy and performance.

[0121] The base material may have a single-layer structure or a multi-layer structure. Furthermore, the substrate may be surface-treated on the surface where the adhesive layer is placed in order to improve adhesion with the adhesive layer.

[0122] The film thickness of the substrate can be appropriately selected according to the application of the adhesive sheet and is not particularly limited. The film thickness of the substrate should be, for example, thick enough to support with the required strength, and a film thickness of about 10 to 200 μm, which has been conventionally used as a substrate film, is preferably used.

[0123] [Release sheet] The release sheet is not particularly limited as long as it can be peeled off from the adhesive layer, and it can have sufficient strength to protect the adhesive layer. Examples of such release sheets include release films and release paper. Furthermore, any known release sheet can be used, and it may have a single-layer structure or a multi-layer structure.

[0124] Examples of single-layer release sheets include release PET film and fluororesin-based film. Furthermore, examples of multilayer release sheets include laminates having release layers on one or both sides of a base layer. Examples of base layers include resin films such as polypropylene, polyethylene, and polyethylene terephthalate, and papers such as fine paper, coated paper, and impregnated paper. The material of the release layer is not particularly limited as long as it has release properties, and examples include silicone compounds, organic compound-modified silicone compounds, fluorine compounds, amino alkyd compounds, melamine compounds, acrylic compounds, polyester compounds, and long-chain alkyl compounds. These compounds can be used in emulsion, solvent, or solvent-free forms. The thickness of the release sheet can be, for example, about 15 to 200 μm.

[0125] [Method for manufacturing adhesive sheets] The adhesive sheet of this disclosure can be manufactured by any suitable method. The adhesive sheet of this disclosure can be obtained by manufacturing a laminate of a substrate or release sheet and an adhesive layer. Such a laminate is, for example, (1) A method of forming an adhesive layer by applying a solution or hot melt of an adhesive composition onto a substrate or release sheet. (2) A method of transferring an adhesive layer applied and formed on a release sheet onto a substrate, in accordance with (1) above. (3) A method of forming and coating an adhesive composition by extruding it onto a substrate, (4) A method of extruding a base layer and an adhesive layer in two or multiple layers, It can be manufactured by any suitable method, such as the above. Among these, the manufacturing method described in (1) above is preferably used.

[0126] Furthermore, the surface of the substrate used in the adhesive sheet of this disclosure can be surface-treated as desired. Examples of surface treatments include (1) discharge treatment such as corona discharge treatment or glow discharge treatment, (2) plasma treatment, (3) flame treatment, (4) ozone treatment, (5) ionizing active ray treatment such as ultraviolet treatment, electron beam treatment, or radiation treatment, (6) roughening treatment such as sand mat treatment or hairline treatment, (7) chemical treatment, and (8) anchor layer formation. Polyurethane resins, polyester resins, acrylic resins, polyester polyurethane resins, etc., can be used as the anchor layer. The thickness of this anchor layer is usually in the range of 0.01 to 1.5 μm.

[0127] As for the method of applying the adhesive composition to the substrate or release sheet, any known method can be appropriately selected. Examples include gravure coating, reverse coating, knife coating, dip coating, spray coating, air knife coating, spin coating, roll coating, printing, immersion and pull-up, curtain coating, die coating, casting, bar coating, extrusion coating, E-type coating, and various printing methods, as well as transfer methods using molds, etc.

[0128] The adhesive composition layer applied to the substrate or release sheet can be converted into an adhesive layer by removing (drying) the solvent as needed and then heating it to thermally crosslink the thermal crosslinking agent.

[0129] The adhesive sheet of this disclosure comprises an adhesive layer which is an adhesive composition containing an adhesive component and the gas generating agent of this disclosure, or a cured product thereof. Through the same action as described above, it has sufficient adhesive strength when in use, but the peeling force from the adherend when peeling is reduced, resulting in an adhesive sheet with excellent ease of peeling from the adherend. Furthermore, since the content of the gas generating agent can be reduced, the adhesive layer is less likely to become cloudy and can be made highly transparent. The adhesive sheet of this disclosure has excellent peelability from the adherend after use, and can therefore be used as a suitable adhesive sheet in cases where the adherend itself or the surface of the protected member is prone to damage due to the thinning of the adherend, integration of functions, and miniaturization of the adherend itself, as various electronic and optical components become more precise and complex, or when the side of the adherend to which the protective sheet is attached is wide and has a large surface area, increasing the force required to peel the protective sheet from the adherend.

[0130] Due to the above-mentioned features, the adhesive sheet of this disclosure can be suitably used as a process adhesive material for the purpose of high adhesion and easy peeling. Specifically, examples include a support for temporary fixing during the polishing process of thick film wafers in the semiconductor chip manufacturing process, a support for temporary fixing when dicing thin film wafers into semiconductor chips, a support for temporary fixing when cutting and chipping a crimped and integrated sheet in the manufacturing process of multilayer ceramic capacitors (MLCCs), a support for temporary fixing in the manufacturing process of flexible printed circuit boards, and a process-use re-peelable adhesive protective sheet for protecting the surface of substrates in the manufacturing processes of flexible printed circuit boards and flexible organic EL displays. [Examples]

[0131] The present disclosure will be described in detail below with reference to examples. These descriptions are not intended to limit the embodiments of the present disclosure. Each compound produced is 1 The chemical structure was confirmed by 1H-NMR measurement (instrument name AVANCE 400MHz, manufactured by BRUKER).

[0132] (Manufacturing Example 1: Manufacturing of Compound 1 (gas generating agent)) In a reactor equipped with a condenser, an additive funnel, a nitrogen inlet, a mechanical stirrer, and a digital thermometer, 15.61 g of methyl ethyl ketone (MEK, manufactured by Showa Ink), 2 g (0.0112 mol) of 5-mercapto-1-phenyl-1H tetrazole (manufactured by Tokyo Chemical Industry), 4.69 g (0.0112 mol) of 2-(perfluorohexyl) ethyl acrylate (Viscote 13F, manufactured by Osaka Organic Chemical Co., Ltd.), and 0.1 g of dimethylphenylphosphine (catalyst: 6 mol% relative to the acrylate) were added. After 10 minutes of nitrogen bubbling, the mixture was brought under a nitrogen atmosphere and stirred at 80°C for 6 hours. After 6 hours, the mixture was allowed to return to room temperature, and liquid-liquid separation was performed with MEK and pure water. MEK was removed by distillation, and after vacuum drying, 5.95 g (0.010 mol, yield 89%) of compound 1, represented by the following formula, was obtained. 1 The synthesis of the target product was confirmed by 1H-NMR (solvent: CDCl3). NMR chemical shift ppm (multiplicity, number of protons): 7.50-7.57 (m, 5H), 4.40-4.44 (m, 2H), 3.60-3.64 (m, 2H), 3.0-3.10 (m, 2H), 2.50-2.60 (m, 2H)

[0133] [ka]

[0134] (Manufacturing Example 2: Manufacturing of Compound 2 (gas generating agent)) Compound 2, represented by the following formula, was obtained in the same manner as in Production Example 1, except that 3.57 g (0.0112 mol) of 2-(perfluorobutyl)ethyl acrylate (manufactured by Tokyo Chemical Industry Co., Ltd.) was used instead of 2-(perfluorohexyl)ethyl acrylate, and 5.4 g (0.0108 mol, yield 97%). 1 The synthesis of the target product was confirmed by 1H-NMR (solvent: CDCl3). NMR chemical shift ppm (multiplicity, number of protons): 7.50-7.57 (m, 5H), 4.40-4.44 (m, 2H), 3.60-3.64 (m, 2H), 3.0-3.10 (m, 2H), 2.50-2.60 (m, 2H)

[0135] [ka]

[0136] (Manufacturing Example 3: Manufacturing of Compound 3 (gas generating agent)) (1) Synthesis of compound intermediate 1 (5-mercapto-1-naphthyl-1Htetrazole) of compound 3 In a reactor equipped with a condenser, an additive funnel, an Ar inlet, a mechanical stirrer, and a digital thermometer, 500 g of acetonitrile (manufactured by Fujifilm Wako Pure Chemical Industries), 25 g (0.135 mol) of 1-naphthyl isothiocyanate (manufactured by Tokyo Chemical Industry Co., Ltd.), 25 g (0.162 mol) of sodium azide (manufactured by Fujifilm Wako Pure Chemical Industries, Ltd.), and 22.1 g (0.162 mol) of zinc chloride (manufactured by Fujifilm Wako Pure Chemical Industries, Ltd.) were added. After 10 minutes of Ar bubbling, the mixture was subjected to an Ar atmosphere and stirred at 80°C for 2 hours. After 2 hours, the mixture was allowed to return to room temperature, concentrated at 35°C, 500 mL of 5 wt% NaOH aqueous solution was added, and the mixture was stirred at room temperature for 30 minutes. Unwanted material was removed by suction filtration, and the organic layer was removed by washing three times with chloroform. 40 mL of concentrated hydrochloric acid was added dropwise, and the mixture was stirred at 0°C to 10°C for 10 minutes. After suction filtration and washing with 150 mL of deionized water, the mixture was dried. 500 mL of acetonitrile was added again for suspension washing, and after concentration, suction filtration and reduced-pressure drying were performed to obtain 13.6 g (0.060 mol, yield 44.2%) of compound intermediate 1 represented by the following formula. 1 The successful synthesis of the target product was confirmed by 1H-NMR (solvent: DMSO-d6). NMR chemical shift ppm (multiplicity, number of protons): 8.23-8.25 (d, 1H), 8.12-8.15 (d, 1H), 7.59-7.80 (m, 4H), 7.42-7.45 (d, 1H)

[0137] (2) Synthesis of compound 3 (gas generator) Compound 3, represented by the following formula, was obtained in the same manner as in Preparation Example 1, except that 2.55 g (0.0112 mol) of compound intermediate 1 was used instead of 5-mercapto-1-phenyl-1H tetrazole, in 6.50 g (0.0101 mol, yield 90%).1 The synthesis of the target product was confirmed by 1H-NMR (solvent: CDCl3). NMR chemical shift ppm (multiplicity, number of protons): 8.07-8.10 (d, 1H), 7.97-8.00 (d, 1H), 7.50-7.60 (m, 5H), 4.40-4.44 (m, 2H), 3.60-3.64 (m, 2H), 3.0-3.10 (m, 2H), 2.50-2.60 (m, 2H)

[0138] [ka]

[0139] (Comparative manufacturing example 1: Manufacturing of comparative compound 1) In the same procedure as in Production Example 1, except that 1.3 g (0.0112 mol) of 5-mercapto-1-methyl-1Htetrazole (manufactured by Tokyo Chemical Industry Co., Ltd.) was used instead of 5-mercapto-1-phenyl-1Htetrazole, 5.68 g (0.0106 mol, yield 95%) of comparative compound 1, represented by the following formula, was obtained. 1 The synthesis of the target product was confirmed by 1H-NMR (solvent: CDCl3). NMR chemical shift ppm (multiplicity, number of protons): 4.40-4.44 (m, 2H), 4.00-4.10 (s, 3H), 3.60-3.64 (m, 2H), 3.0-3.10 (m, 2H), 2.50-2.60 (m, 2H)

[0140] [ka]

[0141] (Comparative manufacturing example 2: Manufacturing of comparative compound 2) In the same procedure as in Production Example 1, except that 1.12 g (0.0112 mol) of ethyl acrylate (manufactured by Tokyo Chemical Industry Co., Ltd.) was used instead of 2-(perfluorohexyl)ethyl acrylate, 2.99 g (0.0108 mol, yield 96%) of comparative compound 2, represented by the following formula, was obtained. 1The synthesis of the target product was confirmed by 1H-NMR (solvent: CDCl3). NMR chemical shift ppm (multiplicity, number of protons): 4.35-4.40 (t, 2H), 3.55-3.60 (t, 2H), 3.0-3.10 (t, 2H), 2.40-2.60 (m, 3H)

[0142] [ka]

[0143] In addition, 5-mercapto-1-phenyl-1Htetrazole (manufactured by Tokyo Chemical Industry Co., Ltd.) was prepared as comparative compound 3.

[0144] [ka]

[0145] [evaluation] <Molar extinction coefficient> The molar extinction coefficient was determined by dissolving the obtained compound in ethyl acetate to a concentration of 0.1 mM, measuring the absorption spectrum in the wavelength range of 230 nm to 800 nm using a UV-Vis spectrophotometer (Shimadzu UV2700), and calculating the value using the absorbance in the obtained absorption spectrum according to the following formula. ε = A / c × d (In the formula, ε represents the molar extinction coefficient, A represents the absorbance, c represents the molar concentration, and d represents the cell thickness.) Table 3 shows the maximum molar extinction coefficient at wavelengths of 240–450 nm and the terminal absorption wavelength on the longer wavelength side where the absorbance is 0.01.

[0146] <Presence or absence of gas generation> 100 parts by mass of (meth)acrylic acid ester polymer (product name: SK Dyne 1811L, manufactured by Soken Chemical Co., Ltd.), 6 parts by mass of thermal crosslinking agent (isocyanate crosslinking agent, product name: Coronate L, manufactured by Nippon Polyurethane Industry Co., Ltd.), 39.4 parts by mass of each of compounds 1-3 and comparative compounds 1-3, and 486.77 parts by mass of solvent (product name: KT-11, manufactured by Showa Ink Co., Ltd.) were mixed and coated onto a PET substrate (product name: Lumirror U34 75μm, manufactured by Toray Industries, Ltd.) using an applicator (manufactured by Yoshimitsu Seiki Co., Ltd.) to a dry film thickness of 50μm. After heating in an 80°C oven for 3 minutes to obtain the adhesive layer, cut it into 25mm widths, peel off the release PET film, and attach the adhesive side of the adhesive sheet to a glass plate substrate (product name: alkali-free glass OA-11, manufactured by Nippon Electric Glass) by rolling a 2kg roller (manufactured by Tester Sangyo) back and forth once. After leaving it for 3 hours under conditions of 23°C and approximately 60% humidity, expose it to an ultra-high pressure mercury lamp at an exposure dose of 3000mJ / cm². 2 Ultraviolet (UV) irradiation was performed, and it was observed whether bubbles formed at the interface with the glass substrate. (Evaluation criteria for whether or not gas is generated) ○: Gas is generated. ×: No gas is produced at all.

[0147] [Table 3]

[0148] (Example 1) (1) Preparation of adhesive composition 100 parts by mass of (meth)acrylic acid ester polymer (product name: SK Dyne 1811L, manufactured by Soken Chemical Co., Ltd.), 50 parts by mass of photocurable polyfunctional compound (product name: Urethane Acrylate U-10PA, manufactured by Shin Nakamura Chemical Co., Ltd.), 1.5 parts by mass of photoinitiator (product name: Omnirad 819, manufactured by IGM Resins BV Co., Ltd.), 6 parts by mass of thermal crosslinking agent (isocyanate-based crosslinking agent, product name: Coronate L, manufactured by Nippon Polyurethane Industry Co., Ltd.), 39.4 parts by mass of compound 1 of production example 1 (gas generating agent), and 659.19 parts by mass of solvent (product name: KT-11, manufactured by Showa Ink Co., Ltd.) were mixed to obtain adhesive composition 1 of Example 1.

[0149] (2) Production of Adhesive Sheet The obtained adhesive composition 1 was applied onto a PET substrate (trade name: Lumirror U34, 75 μm thick, manufactured by Toray Industries, Inc.) with an applicator (manufactured by Yoshimitsu Seiki Co., Ltd.) so that the film thickness after drying would be 50 μm. After heating in an oven at 80°C for 3 minutes, an adhesive layer was obtained. Thereafter, a release PET film (trade name: E7006, manufactured by Toyobo Co., Ltd.) was laminated onto the adhesive layer with a clean roller to produce Adhesive Sheet 1.

[0150] (Examples 2 to 3) (1) Preparation of Adhesive Composition In (1) of Example 1, except that Compound 1 of Production Example 1 was changed to Compound 2 of Production Example 2 or Compound 3 of Production Example 3 respectively, Adhesive Composition 2 or 3 was obtained in the same manner as in (1) of Example 1.

[0151] (2) Production of Adhesive Sheet In (2) of Example 1, except that Adhesive Composition 1 was changed to Adhesive Composition 2 or 3 respectively, Adhesive Sheets 2 or 3 of Example 2 or 3 were obtained in the same manner as in (2) of Example 1.

[0152] (Example 4) (1) Preparation of Adhesive Composition In (1) of Example 1, except that 39.4 parts by mass of Compound 1 (gas generating agent) of Production Example 1 was changed to 6.6 parts by mass of Compound 3 (gas generating agent) of Production Example 3, Adhesive Composition 4 was obtained in the same manner as in (1) of Example 1.

[0153] (2) Production of Adhesive Sheet In (2) of Example 1, except that Adhesive Composition 1 was changed to Adhesive Composition 4, Adhesive Sheet 4 of Example 4 was obtained in the same manner as in (2) of Example 1.

[0154] (Comparative Example 1) (1) Preparation of Comparative Adhesive Composition In (1) of Example 1, except that Compound 1 of Production Example 1 was changed to Comparative Compound 1 of Comparative Production Example 1, Comparative Adhesive Composition 1 was obtained in the same manner as in (1) of Example 1.

[0155] (2) Manufacturing of comparative adhesive sheets Comparative Adhesive Sheet 1 of Comparative Example 1 was obtained in the same manner as in Example 1(2), except that adhesive composition 1 was changed to comparative adhesive composition 1.

[0156] (Comparative Example 2) (1) Preparation of comparative adhesive compositions A comparative adhesive composition 2 was obtained in the same manner as in Example 1(1), except that compound 1 of production example 1 was replaced with comparative compound 2 of comparative production example 2.

[0157] (2) Manufacturing of comparative adhesive sheets Comparative Adhesive Sheet 2 for Comparative Example 2 was obtained in the same manner as in Example 1(2), except that adhesive composition 1 was changed to comparative adhesive composition 2.

[0158] (Comparative Example 3) (1) Preparation of comparative adhesive compositions A comparative adhesive composition 3 was obtained in the same manner as in Example 1(1), except that in Example 1(1), 39.4 parts by mass of compound 1 (gas generating agent) of production example 1 was replaced with 6.6 parts by mass of comparative compound 2 (gas generating agent) of comparative production example 2.

[0159] (2) Manufacturing of comparative adhesive sheets Comparative Adhesive Sheet 3 of Comparative Example 3 was obtained in the same manner as in Example 1(2), except that adhesive composition 1 was changed to comparative adhesive composition 3.

[0160] (Comparative Example 4) (1) Preparation of comparative adhesive compositions A comparative adhesive composition 4 was obtained in the same manner as in Example 1(1), except that compound 1 of production example 1 was changed to comparative compound 3 (5-mercapto-1-phenyl-1Htetrazole (manufactured by Tokyo Chemical Industry Co., Ltd.)) in Example 1(1).

[0161] (2) Manufacturing of comparative adhesive sheets In (2) of Example 1, a comparative adhesive sheet 4 of Comparative Example 4 was obtained in the same manner as in (2) of Example 1, except that the adhesive composition 1 was changed to a comparative adhesive composition 4.

[0162] (Comparative Example 5) (1) Preparation of comparative adhesive composition In (1) of Example 1, a comparative adhesive composition 5 was obtained in the same manner as in (1) of Example 1, except that 39.4 parts by mass of Compound 1 (gas generant) of Production Example 1 was changed to 6.6 parts by mass of Comparative Compound 3 (5-mercapto-1-phenyl-1H-tetrazole).

[0163] (2) Production of comparative adhesive sheet In (2) of Example 1, a comparative adhesive sheet 5 of Comparative Example 5 was obtained in the same manner as in (2) of Example 1, except that the adhesive composition 1 was changed to a comparative adhesive composition 5.

[0164] (Comparative Example 6) (1) Preparation of comparative adhesive composition In (1) of Example 1, a comparative adhesive composition 6 was obtained in the same manner as in (1) of Example 1, except that 39.4 parts by mass of Compound 1 (gas generant) of Production Example 1 was not used.

[0165] (2) Production of comparative adhesive sheet In (2) of Example 1, a comparative adhesive sheet 6 of Comparative Example 6 was obtained in the same manner as in (2) of Example 1, except that the adhesive composition 1 was changed to a comparative adhesive composition 6.

[0166]

Table 4

[0167] [Evaluation] <Presence or absence of gas generation> After cutting the adhesive sheet to a width of 25 mm and peeling off the release PET film, the adhesive side of the sheet was attached to a glass plate substrate (product name: alkali-free glass OA-11, manufactured by Nippon Electric Glass) by rolling a 2 kg roller (manufactured by Tester Sangyo) back and forth once. After leaving it for 3 hours under conditions of 23°C and approximately 60% humidity, it was exposed to a high-pressure mercury lamp at an exposure dose of 3000 mJ / cm². 2 Ultraviolet (UV) irradiation was performed, and it was observed whether bubbles formed at the interface with the glass substrate. (Evaluation criteria for whether or not gas is generated) ○: Gas is generated. ×: No gas is produced at all.

[0168] <Evaluation of peel strength of adhesive layer> The adhesive sheet was cut to a width of 25 mm, and the adhesive layer side of the sheet, after peeling off the release PET film, was attached to a glass plate substrate (product name: alkali-free glass OA-11, manufactured by Nippon Electric Glass) by rolling a 2 kg roller (manufactured by Tester Sangyo) back and forth once. After leaving it for 3 hours under conditions of 23°C and approximately 60% humidity, the peel strength (initial peel strength) before UV irradiation was measured. Subsequently, an ultra-high pressure mercury lamp was used to expose the sheet to an exposure of 3000 mJ / cm². 2 After irradiating with ultraviolet (UV) light, the post-UV irradiation peeling force was measured. The peeling force was measured using a Tensilon (RTF-1150-H, manufactured by A&D) in a 180° tensile test (travel speed 300 mm / min, peeling angle 180 degrees, travel 50 mm).

[0169] <Condition of the adhesive layer> The total light transmittance of the adhesive sheet before UV irradiation was measured using a haze meter (HM150, manufactured by Murakami Color Technology Laboratory) in accordance with JIS K7361-1. (Evaluation criteria for the condition of the adhesive layer) Transparent: Total light transmittance is 80% or higher. Cloudiness: Total light transmittance is less than 80%.

[0170] [Table 5]

[0171] (Summary of results) The adhesive sheets of Examples 1 to 4, which have an adhesive layer that is a cured product of the adhesive composition to which the gas generating agent of this disclosure is added, showed a significantly reduced peel strength after light (UV) irradiation compared to the comparative example, exhibited excellent ease of peeling, and also did not produce cloudiness, and had excellent transparency. As shown in Example 4, the gas generating agent of this disclosure efficiently generates gas even when present in a small amount of 4% by mass in the solid content of the adhesive layer, and it has been revealed that it maintains high adhesive strength before light irradiation while significantly reducing peeling force after light irradiation. On the other hand, in Comparative Example 1, which used the gas generating agent of Comparative Compound 1, gas generation was not observed upon light irradiation, although gas was localized on the surface, and the reduction in peeling force after light irradiation was inferior. In Comparative Examples 2 and 3, which used the gas generating agent of Comparative Compound 2, gas generation was observed on the adhesive layer surface when the gas generating agent content was 20% by mass of the solid content, but no gas generation was observed when the gas generating agent content was reduced to a small amount of 4% by mass of the solid content. In Comparative Examples 2 and 3, the peeling force after light irradiation was almost the same as in Comparative Example 6, which did not use a gas generating agent. Furthermore, in Comparative Example 4, which used the gas generating agent of Comparative Compound 3 as used in the conventional technology, gas generation was observed on the surface of the adhesive layer, but the adhesive layer became cloudy, and the reduction in peel strength after light irradiation was inferior. It is thought that the poor compatibility of the gas generating agent of Comparative Compound 3 caused the clouding of the adhesive layer, leading to UV curing inhibition. In Comparative Example 5, in which the content of the gas generating agent of Comparative Compound 3 was reduced to 4% by mass of the solid content, no gas generation was observed, and the peel strength after light irradiation was inferior to that of Comparative Example 6, which did not use the gas generating agent. [Explanation of Symbols]

[0172] 1 Adhesive layer 2. Substrate or release sheet 3. Release sheet 10 Adhesive Sheets

Claims

[Claim 1] A gas generating agent that is represented by at least one of the following general formulas (1) and (2), has a maximum molar extinction coefficient of 7000 or more at wavelengths of 240 to 450 nm, and generates gas upon light irradiation. 【Chemistry 1】 (In general formulas (1) and (2), Each A independently represents a gas generating unit represented by the following general formula (A-1), (A-2), or (A-3): Each L independently represents either a direct bond or a divalent linking group. Q １ This represents a monovalent fluorinated aliphatic hydrocarbon group or a monovalent organopolysiloxane group, in which the number of carbon atoms directly bonded to a fluorine atom is 2 to 8, and which may contain an ether bond (-O-) in the carbon chain and may have substituents. Q ２ This represents a divalent fluorinated aliphatic hydrocarbon group or a divalent organopolysiloxane group, in which the number of carbon atoms directly bonded to a fluorine atom is 2 to 8, and which may contain ether bonds (-O-) in the carbon chain. 【Chemistry 2】 (In general formulas (A-1), (A-2), and (A-3), R １ represents an aromatic group having 3 to 20 carbon atoms which may have a substituent, R ２ each independently represents a hydrogen atom or a hydrocarbon group having 1 to 20 carbon atoms which may have a substituent, R ３ each independently represents a hydrocarbon group having 1 to 20 carbon atoms which may have a substituent, a cyano group, -COOR ５ , or -CONR ６ R ７ R ４ each independently represents a hydrocarbon group having 1 to 20 carbon atoms which may have a substituent, a cyano group, -COOR ５ , -CONR ６ R ７ , or the above -L-Q １ represents, R ５ and R ７ each independently represents a hydrocarbon group having 1 to 20 carbon atoms which may have a substituent, R ６ represents a hydrogen atom or a hydrocarbon group having 1 to 5 carbon atoms.)

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