Pressure measuring sheet set, method for manufacturing pressure measuring sheet set

Abstract

The present application provides a pressure measurement sheet set and a manufacturing method thereof, which is difficult to deform and damage the coating film even when used at high temperatures. The pressure measurement sheet set of the present application comprises a first sheet having a first support, an adhesive layer, and a first layer comprising microcapsules containing a color developer and an adhesive; and a second sheet having a second support and a second layer containing a color developer. The first and second supports are polyethylene naphthalate sheets or aromatic polyimide sheets. The adhesive layer contains a resin X1 having at least one group selected from an aromatic group, an ester bond, and an imide bond. The capsule wall of the microcapsules contains a resin Y1 having an aromatic group. The adhesive in the first layer has an absorption peak in the infrared absorption spectrum at 3200-3500 cm ‑1 has a top peak or crosslinking. The thickness of the first layer is 0.2 μm or more.

Description

TECHNICAL FIELD

[0001] The present application relates to a sheet set for pressure measurement and a method for manufacturing a sheet set for pressure measurement. BACKGROUND

[0002] In recent years, with high functionality and high definition of products, the necessity of measuring the distribution of pressure is increasing. As a method of measuring the distribution of pressure, a sheet set for pressure measurement is generally used from the viewpoint of convenience.

[0003] For example, in Patent Literature 1 and Patent Literature 2, a sheet set for pressure measurement using microcapsules containing a color developing agent is disclosed.

[0004] The sheet set for pressure measurement is generally composed of a color developing sheet having a color developing agent layer and a color developing sheet having a color developing agent layer.

[0005] Prior Art Documents

[0006] Patent Literature

[0007] Patent Literature 1: International Publication No. 2004 / 024809

[0008] Patent Literature 2: International Publication No. 2018 / 062017 SUMMARY

[0009] Technical Problem to be Solved by the Invention

[0010] The sheet set for pressure measurement is sometimes used in a process such as heat press, heat press, and bonding. In these uses, it is required to use the sheet set for pressure measurement at a high temperature (for example, 180°C or higher).

[0011] As a result of the present inventors' research this time on the pressure measurement sheet set described in Patent Literature 1 and Patent Literature 2, it was confirmed that when used at high temperatures (for example, 180°C or higher), the laminate of the color-developing sheet (1st sheet) and the color-developing sheet (2nd sheet) sometimes deforms due to heat. Also, it was confirmed that problems such as the color-developing sheet and the color-developing sheet excessively adhering at the time of pressurization, the color-developing layer (1st layer) and the color-developing layer (2nd layer) not peeling at the interface at the time of peeling the two, and a portion or all of the color-developing layer adhering to the color-developing layer or a portion or all of the color-developing layer adhering to the color-developing layer (hereinafter also referred to as "coating film breakage occurring") sometimes occur. That is, it was confirmed that in the pressure measurement sheet set described in Patent Literature 1 and Patent Literature 2, accurate pressure measurement sometimes cannot be performed at high temperatures (for example, 180°C or higher). Also, when performing pressure measurement of a measured object that is heated to a high temperature using a pressure measurement sheet set, the actual situation is as follows: for example, as described in the example column of Patent Literature 1, the temperature is temporarily lowered to the allowable temperature of the pressure measurement sheet set (for example, less than 150°C in Patent Literature 1), and then pressure distribution measurement is performed.

[0012] Therefore, an object of the present application is to provide a pressure measurement sheet set in which deformation and coating film breakage are less likely to occur even when used at high temperatures, and a method for manufacturing the same.

[0013] Means for solving the technical problem

[0014] As a result of the present inventors' further research on the above problem, it was found that the above problem can be solved by the following structure.

[0015] 〔1〕 A pressure measurement sheet set comprising:

[0016] a 1st sheet having, in order, a 1st support body, an adhesive layer, and a 1st layer including microcapsules containing a color developer and a binder; and

[0017] a 2nd sheet having a 2nd support body and a 2nd layer containing a color developer,

[0018] the 1st support body and the 2nd support body are polyethylene naphthalate sheets or aromatic polyimide sheets,

[0019] the adhesive layer contains a resin X1 having at least one group selected from the group consisting of an aromatic group, an ester bond, and an imide bond,

[0020] the capsule wall of the microcapsules contains a resin Y1 having an aromatic group,

[0021] the binder in the 1st layer has an absorption peak with a peak top in the infrared absorption spectrum in the range of 3200 to 3500 cm -1 an absorption peak with a peak top or crosslinking,

[0022] The first layer has a thickness of 0.2 μm or more.

[0023] 〔2〕 The sheet set for pressure measurement according to any one of 〔1〕, wherein

[0024] The adhesive in the first layer has one or more of a hydrogen-bonding OH group and a hydrogen-bonding NH group.

[0025] 〔3〕 The sheet set for pressure measurement according to any one of 〔1〕 or 〔2〕, wherein

[0026] The adhesive in the first layer includes a resin having one or more of a hydroxyl group and an amide bond.

[0027] 〔4〕 The sheet set for pressure measurement according to any one of 〔1〕 to 〔3〕, wherein

[0028] The content of the resin X1 is 50% by mass or more relative to the total content of the resin included in the adhesive layer.

[0029] 〔5〕 The sheet set for pressure measurement according to any one of 〔1〕 to 〔4〕, wherein

[0030] The resin X1 includes an acrylic resin, and the adhesive layer has a thickness of 2 to 10 μm.

[0031] 〔6〕 The sheet set for pressure measurement according to any one of 〔1〕 to 〔4〕, wherein

[0032] The resin X1 includes one or more of an acrylic resin and a styrene copolymer.

[0033] 〔7〕 The sheet set for pressure measurement according to any one of 〔1〕 to 〔6〕, wherein

[0034] The adhesive in the first layer includes at least one resin selected from a cellulose-based resin, a polyamide, and a polyvinyl alcohol.

[0035] 〔8〕 The sheet set for pressure measurement according to any one of 〔1〕 to 〔4〕, wherein

[0036] The resin X1 has an aromatic group,

[0037] The adhesive layer further includes a resin X2 having one or more of an amide bond and a hydroxyl group,

[0038] The adhesive in the first layer includes a resin having one or more of a hydroxyl group and an amide bond.

[0039] 〔9〕 The sheet set for pressure measurement according to any one of 1 to 8, wherein

[0040] The first layer further contains a release agent.

[0041] 〔10〕 The sheet set for pressure measurement according to any one of 1 to 9, which satisfies any of (A) to (C) shown below.

[0042] (A) The shrinkage rate S1 in the length direction of the first sheet when heated at 220°C for 10 minutes is 1.0 to 3.0%, and the first support body is a sheet containing polyethylene naphthalate at a rate of 70% by mass or more with respect to the total mass of the sheet.

[0043] (B) The first support body and the second support body are sheets having a thickness of 70 μm or more and containing polyethylene naphthalate at a rate of 70% by mass or more with respect to the total mass of the sheet.

[0044] (C) The first support body and the second support body are aromatic polyimide sheets.

[0045] 〔11〕 The sheet set for pressure measurement according to any one of 1 to 10, wherein

[0046] The heat decomposition temperature of the capsule wall is 250°C or higher.

[0047] 〔12〕 The sheet set for pressure measurement according to any one of 1 to 11, wherein

[0048] The resin Y1 contains at least one resin selected from the group consisting of a polyurethane urea having an aromatic group, a polyurea having an aromatic group, and a melamine resin.

[0049] 〔13〕 The sheet set for pressure measurement according to any one of 1 to 11, wherein

[0050] The resin Y1 has Structure A or Structure B shown below.

[0051] Structure A: a structure obtained by reacting an aromatic or alicyclic diisocyanate, a compound having three or more active hydrogen groups in one molecule, and a polymethylene polyphenyl polyisocyanate.

[0052] Structure B: a structure obtained by reacting melamine with formaldehyde.

[0053] 〔14〕 A production method of a sheet set for pressure measurement, which is the production method of the sheet set for pressure measurement according to any one of 1 to 13, which has:

[0054] a step of forming the adhesive layer by applying a composition containing the resin X1 described above on the first support described above; and

[0055] a step of forming the first layer having a thickness of 0.2 μm or more by applying one composition selected from the composition A and the composition B described below on the adhesive layer,

[0056] the composition A: a composition containing the microcapsule described above and a component for forming an adhesive having one or more of a hydrogen-bonding OH group and a hydrogen-bonding NH group,

[0057] the composition B: a composition containing the microcapsule described above and a component for forming a crosslinked adhesive.

[0058] Effects of the Invention

[0059] According to the present application, a pressure measurement sheet set and a method for manufacturing the same, which are less likely to be deformed and have less damage to a coating film, can be provided. BRIEF DESCRIPTION OF DRAWINGS

[0060] Figure 1 is a cross-sectional view of one embodiment of a pressure measurement sheet set.

[0061] Figure 2 is a diagram for explaining a use mode of the pressure measurement sheet set.

[0062] Figure 3 is another cross-sectional view for explaining the thickness of the first layer of the pressure measurement sheet set.

[0063] Figure 4 is a diagram for explaining "floating" of the laminate. DETAILED DESCRIPTION

[0064] Hereinafter, the present application will be described in detail.

[0065] In the present specification, a numerical range represented by "~" means a range including a lower limit value and an upper limit value represented by the numerical values described before and after the "~".

[0066] In the numerical range described in stages in the present specification, an upper limit value or a lower limit value described in a certain numerical range can be replaced with an upper limit value or a lower limit value of another numerical range described in stages. Also, in the numerical range described in the present specification, an upper limit value or a lower limit value described in a certain numerical range can be replaced with a value shown in the examples.

[0067] Each of the components described later can be used alone or two or more of them can be used in combination. For example, the polyisocyanate described later can be used alone or two or more of them can be used in combination.

[0068] The following description of the components is sometimes based on representative embodiments of the application, and the application is not limited to such embodiments.

[0069] In addition, in the present specification, a numerical range indicated using "~" means a range including a lower limit value and an upper limit value indicated before and after "~".

[0070] Also, in the present specification, "(meth)acrylate" means acrylate and methacrylate, "(meth)acrylic acid" means acrylic acid and methacrylate acid, and "(meth)acrylamide" means acrylamide and methacrylamide.

[0071] (Substituent T)

[0072] As the substituent T, a halogen atom (fluorine atom, chlorine atom, bromine atom, iodine atom, etc.), an alkyl group, a cycloalkyl group, an alkenyl group, a cycloalkenyl group, an alkynyl group, an aryl group, a heterocyclic group, a cyano group, a hydroxyl group, a nitro group, a carboxyl group, an alkoxy group, an aryloxy group, a silyloxy group, a heterocyclic oxy group, an acyloxy group, a carbamoyloxy group, an amino group (including an alkylamino group and an anilino group), an amido group, an aminocarbonylamino group, an alkoxycarbonylamino group, an aryloxycarbonylamino group, a sulfamoylamino group, an alkyl- or arylsulfonylamino group, a mercapto group, an alkylthio group, an arylthio group, a heterocyclic thio group, a sulfamoyl group, a sulfonic acid group, an alkyl- or arylsulfinyl group, an alkyl- or arylsulfonyl group, an acyl group, an aryloxycarbonyl group, an alkoxycarbonyl group, a carbamoyl group, an aryl- or heterocyclic azo group, an imido group, a phosphino group, an oxa-phosphino group, an oxa-phosphino-oxy group, an oxa-phosphino-amino group, a silyl group, and a group including a polymerizable group can be mentioned.

[0073] In the above substituents, the hydrogen atom in the substituent having a hydrogen atom can be further substituted with any of the above substituents.

[0074] [Sheet set for pressure measurement]

[0075] The sheet set for pressure measurement of the present application is provided with:

[0076] a first sheet having, in order, a first support, an adhesive layer, and a first layer including microcapsules containing a color developer and a binder; and

[0077] a second sheet having a second support and a second layer containing a color former,

[0078] the above first support and the above second support are polyethylene naphthalate sheets or aromatic polyimide sheets,

[0079] the above adhesive layer contains a resin X1 having at least one group selected from an aromatic group, an ester bond, and an imide bond,

[0080] the capsule wall of the above microcapsules contains a resin Y1 having an aromatic group,

[0081] The above-mentioned adhesive in the first layer has an absorption peak with a peak top in an infrared absorption spectrum in the range of 3200 to 3500 cm -1 an absorption peak with a peak top or crosslinking,

[0082] The thickness of the above-mentioned first layer is 0.2 μm or more.

[0083] The pressure measuring sheet set of the present application is difficult to cause deformation due to heat even when the laminate of the coinciding first sheet and second sheet is used at a high temperature (for example, 180°C or more). Also, when the first sheet and second sheet are peeled off after pressurization, peeling at the interface of the first layer and second layer is difficult to cause film breakage (in other words, when the first sheet and second sheet are peeled off after pressurization, peeling at the interface of the first layer and second layer is difficult to cause failure of the attachment of a part or all of the second layer to the first layer and / or the attachment of a part or all of the first layer to the second layer).

[0084] The mechanism of action that is presumed to be the main feature point of the pressure measuring sheet set of the present application is described below.

[0085] As the first feature point of the pressure measuring sheet set of the present application, the use of a resin sheet with relatively high heat resistance, namely a polyethylene naphthalate sheet or an aromatic polyimide sheet, as each support of the first sheet and second sheet, the use of an adhesive contained in the first layer of the first sheet that has an absorption peak with a peak top in an infrared absorption spectrum in the range of 3200 to 3500 cm -1 the adhesive that is an absorption peak with a peak top or a crosslinking adhesive and the fact that the capsule wall of the microcapsule contained in the first layer of the first sheet contains a resin with an aromatic group. Also, as described later, the adhesive that is an absorption peak with a peak top in an infrared absorption spectrum in the range of 3200 to 3500 cm -1 The adhesive that is an absorption peak with a peak top refers to an adhesive with one or more of a hydrogen-bonding OH group and a hydrogen-bonding NH group (i.e., an adhesive with one or more functional groups including an OH group and an NH group and forming a network through hydrogen bonding by the OH group and / or NH group). The pressure measuring sheet set of the present application, by having the structure of the above-mentioned first feature point, can inhibit the laminate of the coinciding first sheet and second sheet from deforming due to heat even when used at a high temperature (for example, 180°C or more). Also, since the capsule wall of the microcapsule and the adhesive in the first layer are formed of a material that is difficult to melt at a high temperature (for example, 180°C or more), the excessive attachment of the first sheet and second sheet at the time of pressurization (particularly, the failure of a part or all of the second layer to attach to the first sheet when the first sheet and second sheet are peeled off after pressurization) can be inhibited.

[0086] Further, as the second feature point of the pressure measurement sheet set of the present application, there can be mentioned the point that the first sheet has an adhesive layer between the first support and the color developing layer, the adhesive layer containing a resin having a prescribed functional group (resin X1). In the pressure measurement sheet set of the present application, by virtue of the structure having the above-mentioned second feature point, the adhesion of the first support to the first layer in the first sheet can be ensured.

[0087] That is, the pressure measurement sheet set of the present application, by virtue of the combined action of the respective mechanisms based on the above-mentioned first and second feature points, can suppress deformation of the laminate of the superimposed first and second sheets due to heat even in the case of use at a high temperature (for example, 180°C or higher), and can achieve peeling at the interface of the first and second layers when the first and second sheets are peeled after pressurization, and thus can suppress damage to the coating film.

[0088] Further, in the following, the following cases are sometimes referred to as "the effects of the present application are more excellent": the case where deformation of the laminate of the superimposed first and second sheets can be more suppressed in the case of use of the pressure measurement sheet set of the present application at a high temperature (for example, 180°C or higher), and / or the case where the peeling property at the interface of the first and second layers is more excellent when the first and second sheets are peeled after pressurization in the case of use of the pressure measurement sheet set of the present application at a high temperature (for example, 180°C or higher), and damage to the coating film can be more suppressed.

[0089] In the present specification, the "adhesive in the first layer does not have an absorption peak having a peak top in the wave number region of 3200 to 3500 cm -1 "absorption peak having a peak top" means that an absorption peak having a peak top is observed in the infrared absorption spectrum in the wave number region of 3200 to 3500 cm -1 "absorption peak having a peak top" means that an absorption peak having a peak top is observed in the infrared absorption spectrum in the wave number region of 3200 to 3500 cm -1 "absorption peak having a peak top" means that an absorption peak having a peak top is observed in the infrared absorption spectrum in the wave number region of 3200 to 3500 cm -1 "absorption peak having a peak top" means that an absorption peak having a peak top is observed in the infrared absorption spectrum in the wave number region of 3200 to 3500 cm

[0090] Further, in the present specification, the "adhesive in the first layer has an absorption peak having a peak top in the wave number region of 3200 to 3500 cm -1 "absorption peak having a peak top" means that an absorption peak having a peak top is observed in the infrared absorption spectrum in the wave number region of 3200 to 3500 cm -1 "absorption peak having a peak top" means that an absorption peak having a peak top is observed in the infrared absorption spectrum in the wave number region of 3200 to 3500 cm

[0091] 〔First Embodiment〕

[0092] Figure 1 is a cross-sectional view of one embodiment of the pressure measurement sheet set.

[0093] The pressure measurement sheet set 10 has a first sheet 16 and a second sheet 22. The first sheet 16 has a first support 12, an adhesive layer 13 disposed on the first support 12, and a first layer 14 including microcapsules 14A and an adhesive 14B. The second sheet 22 has a second support 18, and a second layer 20 including a color developer disposed on the second support 18.

[0094] As shown in FIG. 1, in use of the pressure measurement sheet set 10, the first sheet 16 and the second sheet 22 are stacked so that the first layer 14 in the first sheet 16 and the second layer 20 in the second sheet 22 face each other, and are used. By pressing at least one of the first support 12 side of the first sheet 16 and the second support 18 side of the second sheet 22 in the obtained stack, the microcapsules are broken in the pressed region, and the color developer contained in the microcapsules comes out of the microcapsules, and performs a color development reaction with the color developer in the second layer 20. As a result, color development is performed in the pressed region. Figure 2

[0095] In the present embodiment, the second support 18 and the second layer 20 are in a state of being directly stacked, but are not limited to this, and as described later, another layer (for example, an adhesive layer or an easy-adhesion layer) can be disposed between the second support 18 and the second layer 20. Figure 1

[0096] Hereinafter, the structure of the first sheet 16 and the second sheet 22 forming the pressure measurement sheet set 10 will be described in detail.

[0097] <<First Sheet>>

[0098] Figure 1 The first sheet 16 described in the present embodiment has a first support 12, an adhesive layer 13, and a first layer 14 including microcapsules 14A containing a color developer and an adhesive 14B.

[0099] The first sheet 16 can be a single leaf (single sheet), or can be a long strip shape.

[0100] With respect to the first sheet 16, when heated at 220°C for 10 minutes, the shrinkage rate S1 of the first sheet 16 in the length direction and the shrinkage rate S2 of the first sheet 16 in the width direction orthogonal to the length direction are preferably both -0.5 to 3.0%, and more preferably 1.0 to 3.0% from the viewpoint that the effects of the present application are more excellent.

[0101] ​​The length direction of the first sheet 16 refers to the long dimension direction of the first sheet 16, and specifically, in the case where the first sheet 16 is rectangular, refers to the direction along the long side. Also, the width direction of the first sheet 16 refers to the direction orthogonal to the length direction (short side direction) of the first sheet 16, and for example, in the case where the first sheet 16 is rectangular, refers to the direction along the short side. However, in the case where the first sheet 16 is square, the direction along an arbitrarily selected one side is taken as the length direction, and the direction along the side orthogonal thereto is taken as the width direction.

[0102] Further, the measurement method of the shrinkage S1 and the shrinkage S2 of the first sheet 16 is as shown in the column of Examples.

[0103] In the first sheet 16, from the viewpoint of being able to perform more precise pressure distribution measurement, the absolute value of the difference between the shrinkage S1 and the shrinkage S2 (|S1-S2|) is preferably 0 to 0.8%, more preferably 0 to 0.6%, and further preferably 0 to 0.4%.

[0104] Hereinafter, each component will be described in detail.

[0105] <First support>

[0106] The first support is a component for supporting the first layer.

[0107] The first support is a polyethylene naphthalate (PEN) sheet or an aromatic polyimide (PI) sheet. From the viewpoint of being easily visually recognized at the time of color development, a polyethylene naphthalate sheet is preferable.

[0108] The polyethylene naphthalate (PEN) sheet refers to a sheet containing polyethylene naphthalate at a rate of 50% by mass or more with respect to the total mass of the sheet. From the viewpoint of being able to more suppress deformation, in the polyethylene naphthalate (PEN) sheet, the content of polyethylene naphthalate is preferably 70% by mass or more, more preferably 90% by mass or more, and further preferably 98% by mass or more with respect to the total mass of the sheet. Further, the upper limit value is not particularly limited, and for example, is 100% by mass or less.

[0109] Further, the above-described polyethylene naphthalate can be a homopolymer, or can be a part of a copolymer (in other words, can be contained as a structural unit of a copolymer). In the case where the polyethylene naphthalate is a part of a copolymer, the content of the polyethylene naphthalate (for example, a structural unit obtained by polycondensation of naphthalene dicarboxylic acid or a derivative thereof and ethylene glycol) is preferably 50% by mass or more, and preferably 70% by mass or more with respect to the total structural unit in the copolymer. Further, the upper limit value is 100% by mass or less.

[0110] As the copolymer containing polyethylene naphthalate as a part thereof, for example, polyethylene naphthalate / polyethylene terephthalate copolymer (PEN / PET copolymer) can be mentioned. The copolymer containing polyethylene naphthalate as a part thereof can be a random copolymer or a block copolymer, and is preferably a random polymer.

[0111] As the commercially available product of the polyethylene naphthalate film, Theonex (registered trademark) Q51, Q53, Q81, and Q83 (manufactured by TOYOBO FILM SOLUTIONS LIMITED), and the like can be mentioned.

[0112] The aromatic polyimide (PI) sheet refers to a sheet containing an aromatic polyimide at a rate of 50% by mass or more with respect to the total mass of the sheet. From the viewpoint of being able to more suppress deformation, in the aromatic polyimide (PI) sheet, the content of the aromatic polyimide is preferably 70% by mass or more, more preferably 90% by mass or more, and further preferably 98% by mass or more with respect to the total mass of the sheet. In addition, the upper limit value is not particularly limited, and is, for example, 100% by mass or less.

[0113] Also, the above-described aromatic polyimide can be a homopolymer or a part of a copolymer (in other words, can be contained as a structural unit of a copolymer). In the case where the aromatic polyimide is a part of a copolymer, the content of the aromatic polyimide is preferably 50% by mass or more, and preferably 70% by mass or more with respect to the total structural unit in the copolymer. In addition, the upper limit value is 100% by mass or less.

[0114] As the commercially available product of the polyimide film, Kapton (registered trademark) H, V, and EN (manufactured by TORAY INDUSTRIES, INC.) and Apical AH, NPI, and AF (manufactured by Kaneka Corporation), and the like can be mentioned.

[0115] As the lower limit value of the thickness of the first support, 10 μm or more, more preferably 40 μm or more, and further preferably 70 μm or more are preferable from the viewpoint of being able to more suppress deformation. Also, as the upper limit value, 300 μm or less, more preferably 200 μm or less, further preferably 150 μm or less, and particularly preferably 125 μm or less are preferable. As one mode of the thickness of the first support, for example, 40 to 120 μm can be mentioned.

[0116] Regarding the first support body, the shrinkage S1 in the longitudinal direction and the shrinkage S2 in the width direction orthogonal to the longitudinal direction are preferably both -0.5 to 3.0% when heated at 220°C for 10 minutes, and more preferably 1.0 to 3.0% from the viewpoint of more excellent effects of the present application.

[0117] The preferred range of the absolute value of the difference between the shrinkage S1 and the shrinkage S2 of the first support body is the same as that of the first sheet 16.

[0118] The measurement method of the shrinkage S1 and the shrinkage S2 of the first support body is the same as that of the first sheet 16 except that the first support body is used instead of the first sheet 16.

[0119] The definition of the longitudinal direction and the width direction in the first support body is the same as that of the first sheet 16 except that the first sheet 16 is changed to the first support body.

[0120] <Adhesive layer>

[0121] The adhesive layer is a layer that improves the adhesion of the first support body to the first layer.

[0122] The adhesive layer contains a resin X1 (hereinafter also referred to as "resin X1") having at least one group selected from the group consisting of an aromatic group, an ester bond (-CO-O-), and an imide bond (-CO-N-CO-) (hereinafter also referred to as "specific functional group").

[0123] In the resin X1, the specific functional group can be contained in the main chain or in the side chain.

[0124] As the aromatic group, either one of an aromatic hydrocarbon ring group and an aromatic heterocyclic group can be used.

[0125] As the aromatic hydrocarbon ring contained in the aromatic hydrocarbon ring group, either a monocyclic structure or a fused ring structure (fused ring structure) in which two or more rings are fused can be used. Furthermore, the aromatic hydrocarbon ring can have a substituent (as the substituent, for example, the groups exemplified in the above-described substituent T can be used). The number of carbon atoms of the aromatic hydrocarbon ring is not particularly limited, and is preferably 6 to 30, more preferably 6 to 18, and further preferably 6, and particularly preferably a benzene ring.

[0126] As the heteroatom (atom other than carbon atom and hydrogen atom) included in the aromatic heterocycle, for example, a sulfur atom, an oxygen atom, or a nitrogen atom is preferable, and a nitrogen atom is more preferable. The number of carbon atoms in the aromatic heterocycle is not particularly limited, and is preferably 3 to 30, and more preferably 3 to 18. The number of heteroatoms in the aromatic heterocycle is not particularly limited, and is usually about 1 to 10, and is preferably 1 to 4, and more preferably 1 to 2. The number of ring members of the aromatic heterocycle is not particularly limited, and is preferably 3 to 8, and more preferably 5 to 7, and further preferably 5 to 6.

[0127] As the aromatic heterocycle included in the aromatic heterocyclic group, a monocyclic structure or a condensed ring structure (fused ring structure) in which two or more rings are condensed can be used. In the case of a condensed ring structure, an aromatic hydrocarbon ring (for example, benzene ring) having no heteroatom can be included. Furthermore, the aromatic heterocycle can have a substituent (as the substituent, for example, the groups exemplified in the above-described substituent T can be used).

[0128] As one mode of the resin X1 having a specific functional group, a styrene-based resin, an acrylic-based resin, a polyester-based resin, a polyimide-based resin, and the like can be used, and from the viewpoint of more excellent effects of the present application, a styrene-based resin or an acrylic-based resin is preferable among these.

[0129] In addition, the above-described styrene-based resin refers to a resin including a repeating unit derived from styrene. In addition, the above-described repeating unit derived from styrene can have a substituent (as the substituent, for example, the groups exemplified in the above-described substituent T can be used).

[0130] As one mode of the styrene-based resin, the content of the repeating unit derived from styrene is preferably 20 to 100% by mass with respect to the total repeating units.

[0131] In addition, as another mode of the styrene-based resin, a copolymer of a repeating unit derived from styrene and a repeating unit other than the repeating unit derived from styrene (styrene copolymer) is also preferable. In addition, as the styrene copolymer, the content of the repeating unit derived from styrene is preferably 20% by mass or more, more preferably 30% by mass or more, and further preferably 40% by mass or more with respect to the total repeating units. In addition, as the upper limit value, it is preferably less than 100% by mass, more preferably 90% by mass or less, further preferably 80% by mass or less, and particularly preferably 70% by mass or less.

[0132] As the above-described styrene copolymer, for example, a styrene-diene copolymer; a resin including a repeating unit derived from styrene, a repeating unit derived from (meth)acrylate, and a repeating unit derived from (meth)acrylic acid; a resin including a repeating unit derived from styrene and a repeating unit derived from (meth)acrylate; and the like can be used.

[0133] Further, as the acrylic resin, a resin containing a repeating unit derived from a (meth)acrylate and / or a repeating unit derived from a (meth)acrylic acid is meant. As one mode of the acrylic resin, the content of one or more of the repeating unit derived from a (meth)acrylate and the repeating unit derived from a (meth)acrylic acid is preferably 50% by mass or more, more preferably 65% by mass or more, further preferably 75% by mass or more, and particularly preferably 85% by mass or more, relative to the total repeating units. Further, as the upper limit, 100% by mass or less is meant. As the number of carbon atoms in the alkyl moiety in the above-mentioned poly(meth)acrylate, no particular limitation is imposed, and for example, 1 to 10, more preferably 1 to 6, and further preferably 1 to 3 are meant. Further, the above-mentioned repeating unit derived from a (meth)acrylate and the repeating unit derived from a (meth)acrylic acid can have a substituent (as the substituent, for example, the groups exemplified in the above-mentioned substituent T can be mentioned).

[0134] As a specific example of the resin X1 having a specific functional group, for example, polystyrene, styrene butadiene rubber (SBR), polyethylene terephthalate (PET), polyethylene glycol (PEG) / caprolactone copolymer, polypropylene glycol (PPG) / caprolactone copolymer, poly(meth)acrylic acid, poly(meth)acrylate, polyimide, styrene / (meth)acrylic acid copolymer, styrene / (meth)acrylate copolymer, styrene / (meth)acrylic acid / (meth)acrylate copolymer, styrene / butadiene / (meth)acrylic acid copolymer, styrene / butadiene / (meth)acrylate copolymer, and styrene / butadiene / (meth)acrylic acid / (meth)acrylate copolymer, and the like can be mentioned.

[0135] As one preferred mode of the adhesive layer, the resin X1 has an aromatic group, and it is also preferable that the resin X2 further contain one or more of a resin having an amide bond and a hydroxyl group.

[0136] As the above-mentioned resin X2, for example, carboxymethyl cellulose, carboxyethyl cellulose, methyl cellulose, ethyl cellulose, hydroxymethyl cellulose, hydroxyethyl cellulose, methylhydroxypropyl cellulose, hydroxypropylmethyl cellulose, crystalline cellulose, xanthan gum, guar gum, hydroxyethyl guar gum, carboxymethyl guar gum, tragacanth gum, locust bean gum, gum ghatti, psyllium seed, carrageenan, polygalactose, gum arabic, pectin, polytriglucose, mannose, glucomannan, starch, curdlan, carrageenan, chondroitin sulfate, dermatan sulfate, glycogen, heparan sulfate, hyaluronic acid, keratan sulfate, chondroitin, mucin sulfate, dextran, keratan sulfate, succinoglucan, gellan gum, alginic acid, propylene glycol alginate, polyethylene glycol, chitin, chitosan, carboxymethyl chitin, gelatin, casein, gum arabic, agar, curdlan, and polyvinyl alcohol, and the like can be mentioned.

[0137] The content of the resin X1 in the adhesive layer is preferably 10 to 100 mass% relative to the total content of the resins contained in the adhesive layer.

[0138] When the adhesive layer is formed of 1 layer, the content of the one or more resins selected from the group consisting of styrene-based resins and acrylic resins in the above adhesive layer is preferably 50 to 100 mass% relative to the total mass of the resins contained in the adhesive layer.

[0139] As a lower limit value of the thickness of the adhesive layer, 0.01 μm or more, more preferably 0.1 μm or more is preferable. Also, as an upper limit value, 10 μm or less, more preferably 5 μm or less is preferable.

[0140] As one mode of the thickness of the adhesive layer, 0.01 to 10 μm, more preferably 0.1 to 5 μm can be given.

[0141] Also, as another one mode of the thickness of the adhesive layer, 2 to 10 μm, more preferably 2 to 5 μm can be given.

[0142] <First Layer>

[0143] (Microcapsule)

[0144] The first layer contains a microcapsule containing a color former.

[0145] Hereinafter, first, the material constituting the microcapsule is described in detail.

[0146] Generally, the microcapsule has a core portion and a capsule wall for containing a core material (contained (also referred to as a contained component.) forming the core portion.

[0147] In the present application, the microcapsule contains a color former as a core material (a contained component). The color former is contained in the microcapsule, and thus the color former can stably exist until the microcapsule is broken by pressurization.

[0148] The microcapsule has a capsule wall containing a core material.

[0149] The capsule wall in the microcapsule contains a resin having an aromatic group (hereinafter also referred to as "resin Y1").

[0150] Here, the meaning of the aromatic group is the same as the "aromatic group" given as the specific functional group possessed by the resin X1 contained in the above adhesive layer.

[0151] The capsule wall of the microcapsule is preferably formed substantially of a resin. Substantially formed of a resin means that the content of the resin is 90 mass% or more, preferably 100 mass% relative to the total mass of the capsule wall.

[0152] In the resin forming the microcapsule wall, the content of the resin Y1 is preferably 80% by mass or more, more preferably 90% by mass or more, and further preferably 95% by mass or more, relative to the total mass of the resin. In addition, the upper limit is 100% by mass or less.

[0153] As a preferred form of the resin Y1, it is preferable to contain at least one selected from the group consisting of a polyurea having an aromatic group, a polyurethane urea having an aromatic group, a polyurethane having an aromatic group, and a melamine resin (for example, a melamine-formaldehyde resin). From the viewpoint that the effects of the present application are more excellent, among these, it is more preferable to contain at least one selected from the group consisting of a polyurethane urea having an aromatic group, a polyurethane urea having an aromatic group, and a melamine resin, and it is further preferable to contain a polyurethane urea having a polymethylene polyphenyl linking group or a melamine-formaldehyde resin.

[0154] In addition, the polyurethane refers to a polymer having a plurality of urethane bonds, and is preferably a reaction product formed from raw materials containing a polyol and a polyisocyanate (preferably an aromatic isocyanate).

[0155] Also, the polyurea refers to a polymer having a plurality of urea bonds, and is a reaction product formed from raw materials preferably containing a polyamine and a polyisocyanate (preferably an aromatic isocyanate). In addition, the polyurea can be synthesized using a polyisocyanate without using a polyamine, by allowing a part of the polyisocyanate to react with water to become a polyamine.

[0156] Also, the polyurethane urea refers to a polymer having a urethane bond and a urea bond, and is preferably a reaction product formed from raw materials containing a polyol, a polyamine, and a polyisocyanate (preferably an aromatic isocyanate). In addition, when a polyol is reacted with a polyisocyanate, a part of the polyisocyanate reacts with water to become a polyamine, and as a result, a polyurethane urea is obtained.

[0157] Also, as the melamine-formaldehyde resin, it is preferable to be a reaction product formed by polycondensation of melamine and formaldehyde.

[0158] The polyisocyanate refers to a compound having two or more isocyanate groups, and examples include aromatic polyisocyanates and aliphatic polyisocyanates. From the viewpoint that an aromatic ring group can be introduced into the capsule wall of the microcapsule, it is preferable to be an aromatic polyisocyanate.

[0159] As the aromatic polyisocyanate, for example, aromatic diisocyanates can be mentioned, for example, m-phenylene diisocyanate, p-phenylene diisocyanate, 2,6-toluene diisocyanate, 2,4-toluene diisocyanate, naphthalene-1,4-diisocyanate, diphenylmethane-4,4'-diisocyanate, 3,3'-dimethoxy-biphenyl diisocyanate, 3,3'-dimethyl diphenylmethane-4,4'-diisocyanate, tolylene-1,4-diisocyanate, tolylene-1,3-diisocyanate, 4-chlorotolylene-1,3-diisocyanate, 2-methyltolylene-1,3-diisocyanate, 4,4'-diphenylpropane diisocyanate, and 4,4'-diphenylhexafluoropropane diisocyanate.

[0160] As the aliphatic polyisocyanate, aliphatic diisocyanates can be mentioned, for example, trimethylene diisocyanate, hexamethylene diisocyanate, propylene-1,2-diisocyanate, butylene-1,2-diisocyanate, cyclohexylene-1,2-diisocyanate, cyclohexylene-1,3-diisocyanate, cyclohexylene-1,4-diisocyanate, dicyclohexylmethane-4,4'-diisocyanate, 1,4-bis(isocyanatomethyl)cyclohexane, 1,3-bis(isocyanatomethyl)cyclohexane, isophorone diisocyanate, lysine diisocyanate, and hydrogenated tolylene diisocyanate.

[0161] Further, the above-mentioned examples illustrate 2-functional aromatic polyisocyanates and aliphatic polyisocyanates, but as the polyisocyanate, 3-functional or more polyisocyanates (for example, 3-functional triisocyanates and 4-functional tetraisocyanates) can also be mentioned.

[0162] More specifically, as the polyisocyanate, trimers of the above-mentioned 2-functional polyisocyanates, i.e., buret bodies or isocyanurate bodies, adducts of polyols such as trimethylolpropane and 2-functional polyisocyanates, formalin condensates of benzisocyanurate, polyisocyanates having a polymerizable group such as methacryloyloxyethyl isocyanate, and lysine triisocyanate can also be mentioned.

[0163] As for the polyisocyanate, it is described in "Polyurethane Resin Handbook" (edited by Keiji Iwata, published by NIKKAN KOGYO SHIMBUN, LTD. (1987)).

[0164] Among them, as one of the preferable modes of the polyisocyanate, 3-functional or more polyisocyanates are preferable.

[0165] As the 3-functional or more polyisocyanate, for example, 3-functional or more aromatic polyisocyanates and 3-functional or more aliphatic polyisocyanates can be mentioned.

[0166] As the polyisocyanate of 3 or more functions, an adduct (addition product) of an aromatic or alicyclic diisocyanate and a compound having 3 or more active hydrogen groups in one molecule (for example, a polyol, a polyamine, or a polythiol of 3 or more functions, etc.) that is a polyisocyanate of 3 or more functions (adduct type polyisocyanate of 3 or more functions) and a trimer of an aromatic or alicyclic diisocyanate (biuret type or isocyanurate type) are preferable, and the adduct (addition product) that is a polyisocyanate of 3 or more functions is more preferable.

[0167] As the polyisocyanate of 3 or more functions, an adduct of an aromatic or alicyclic diisocyanate and a polyol having 3 or more hydroxyl groups in one molecule that is a polyisocyanate of 3 or more functions is preferable, and an adduct of an aromatic or alicyclic diisocyanate and a polyol having 3 hydroxyl groups in one molecule that is a polyisocyanate of 3 functions is more preferable.

[0168] As the adduct, from the viewpoint of being able to perform more precise pressure distribution measurement at high temperatures, an adduct obtained using an aromatic diisocyanate is preferable.

[0169] As the polyol, for example, a low molecular polyol of 3 or more functions described later is preferable, and trimethylolpropane is more preferable.

[0170] As the adduct type polyisocyanate of 3 or more functions, for example, TAKENATE (registered trademark) D-102, D-103, D-103H, D-103M2, P49-75S, D-110N, D-120N, D-140N, D-160N (manufactured by Mitsui Chemicals, Inc.), Desmodur (registered trademark) L75, UL57SP (manufactured by Sumika Bayer Urethane Co., Ltd.), Coronate (registered trademark) HL, HX, L (manufactured by Nippon Polyurethane Industry Co., Ltd.), P301-75E (manufactured by Asahi Kasei Corporation), Barnock (registered trademark) D-750 (manufactured by DIC Corporation) can be given.

[0171] Among these, as the adduct type polyisocyanate of 3 or more functions, TAKENATE (registered trademark) D-110N, D-120N, D-140N, D-160N (manufactured by Mitsui Chemicals, Inc.) or Barnock (registered trademark) D-750 manufactured by DIC Corporation is preferable.

[0172] As the isocyanurate type polyisocyanate of 3 or more functions, for example, TAKENATE (registered trademark) D-127N, D-170N, D-170HN, D-172N, D-177N, D-204 (manufactured by Mitsui Chemicals, Inc.), SUMIDUR N3300, Desmodur (registered trademark) N3600, N3900, Z4470BA (manufactured by Sumika Bayer Urethane Co., Ltd.), Coronate (registered trademark) HX, HK (manufactured by Nippon Polyurethane Industry Co., Ltd.), Duramate (registered trademark) TPA-100, TKA-100, TSA-100, TSS-100, TLA-100, TSE-100 (manufactured by Asahi Kasei Corporation) can be given.

[0173] As the biuret type polyisocyanate of 3 or more functions, for example, TAKENATE (registered trademark) D-165N, NP1100 (manufactured by Mitsui Chemicals, Inc.), Desmodur (registered trademark) N3200 (manufactured by Sumika Bayer Urethane Co., Ltd.), Duramate (registered trademark) 24A-100 (manufactured by Asahi Kasei Corporation) can be given.

[0174] Also, as the polyisocyanate, a polymethylene polyphenyl polyisocyanate is also preferable.

[0175] The polymethylene polyphenyl polyisocyanate is preferably a compound represented by formula (X).

[0176] [Chemical Formula 1]

[0177]

[0178] In formula (1), n represents the number of repeating units. As the number of repeating units, an integer of 1 or more is represented, and from the viewpoint that more precise pressure distribution measurement can be performed at high temperatures, n is preferably an integer of 1 to 10, and more preferably an integer of 1 to 5.

[0179] As the polyisocyanate containing a polymethylene polyphenyl polyisocyanate, for example, MILLIONATE MR-100, MILLIONATE MR-200, MILLIONATE MR-400 (manufactured by TOSOH CORPORATION), WANNATE PM-200, WANNATE PM-400 (manufactured by Manka Japan Co., Ltd.), Cosmonate M-50, Cosmonate M-100, Cosmonate M-200, Cosmonate M-300 (manufactured by Mitsui Chemicals, Inc.), and VORANATE M-595 (manufactured by Dow Chemical Company) can be given.

[0180] The polyol is a compound having 2 or more hydroxyl groups, and for example, low-molecular polyols (examples: aliphatic polyols, aromatic polyols), polyvinyl alcohols, polyether-based polyols, polyester-based polyols, polylactone-based polyols, castor oil-based polyols, polyolefin-based polyols, and amine-based compounds containing a hydroxyl group can be given.

[0181] Further, the low-molecular polyol refers to a polyol having a molecular weight of 400 or less, and for example, 2-functional low-molecular polyols such as ethylene glycol, diethylene glycol, and propylene glycol, and 3-functional or more low-molecular polyols such as glycerol, trimethylolpropane, hexanetriol, pentaerythritol, and sorbitol can be given.

[0182] Further, as the amine-based compound containing a hydroxyl group, for example, an amino compound such as an oxyalkylated derivative can be given, and an amino alcohol can be given. As the amino alcohol, for example, an oxirane or oxrane adduct of an amino compound such as ethylenediamine, i.e., N,N,N',N'-tetra[2-hydroxypropyl]ethylenediamine, N,N,N',N'-tetra[2-hydroxyethyl]ethylenediamine, and the like can be given.

[0183] The polyamine is a compound having 2 or more amino groups (primary or secondary amino groups), and for example, aliphatic polyamines such as diethylenetriamine, triethylenetetramine, 1,3-propanediamine, hexamethylenediamine, and the like; an epoxy compound adduct of an aliphatic polyamine; a piperazine alicyclic polyamine; a heterocyclic diamine such as 3,9-bis-aminopropyl-2,4,8,10-tetraoxaspiro-(5,5)undecane can be given.

[0184] Among these, as the resin Y1, it is preferable to use a 3-functional or more polyisocyanate A (hereinafter, also simply referred to as "polyisocyanate A") which is an adduct of an aromatic or alicyclic diisocyanate and a compound having 3 or more active hydrogen groups in 1 molecule, and a polyisocyanate B (hereinafter, also simply referred to as "polyisocyanate B") selected from an aromatic diisocyanate and a polymethylene polyphenyl polyisocyanate.

[0185] That is, the capsule wall is preferably a capsule wall containing the resin Y1 formed using the above-described polyisocyanate A and the polyisocyanate B.

[0186] When the above-described polyisocyanate A and the polyisocyanate B are used, the temperature dependency of color development is small. In addition, the temperature dependency of color development refers to a characteristic indicating a difference in the degree of color development based on the temperature at the time of applying pressure to the pressure measurement sheet set.

[0187] In addition, as the polyisocyanate B, either an aromatic diisocyanate alone or a polymethylene polyphenyl polyisocyanate alone can be used, or both can be used in a mixture. Among them, as the polyisocyanate B, a mixture of an aromatic diisocyanate and a polymethylene polyphenyl polyisocyanate is preferable.

[0188] In the above-described mixture, the mass ratio of the polymethylene polyphenyl polyisocyanate to the aromatic diisocyanate (mass of the polymethylene polyphenyl polyisocyanate / mass of the aromatic diisocyanate) is not particularly limited, and is preferably 0.1 to 10, more preferably 0.5 to 2, and further preferably 0.75 to 1.5.

[0189] In the case where the polyisocyanate A and the polyisocyanate B are used together, the mass ratio of the above-described polyisocyanate A to the polyisocyanate B (mass of the polyisocyanate A / mass of the polyisocyanate B) is not particularly limited, and is preferably 98 / 2 to 20 / 80, more preferably 80 / 20 to 20 / 80, and further preferably 80 / 20 to 45 / 55.

[0190] When the above-described mass ratio is within the above-described range, more precise pressure distribution measurement can be performed at a high temperature. Also, the temperature dependency of color development is small.

[0191] Also, as an example of a preferable mode of the resin Y1, a case having Structure A or Structure B shown below can be cited.

[0192] Structure A: a structure formed by reacting an aromatic or alicyclic diisocyanate, a compound having three or more active hydrogen groups in one molecule, and a polymethylene polyphenyl polyisocyanate (preferably a compound represented by Formula (X)).

[0193] Structure B: a structure formed by reacting melamine with formaldehyde.

[0194] In the above-described Structure A, as the above-described active hydrogen group, a hydroxyl group or an amino group is preferable, and a hydroxyl group is more preferable.

[0195] The thermal decomposition temperature of the capsule wall of the microcapsule is preferably 250°C or higher, more preferably 255°C or higher, and even more preferably 260°C or higher. There is no particular limitation on the upper limit, and cases of 500°C or lower are common.

[0196] As a method for measuring the thermal decomposition temperature of the capsule wall, the following method was used.

[0197] Fifty pieces of the first layer (microcapsule layer) of 1 cm in length and 1 cm in width were prepared, and all of them were immersed in 10 mL of water, and left to stand for 24 hours to obtain an aqueous dispersion of microcapsules. In the case where the first sheet includes the first support, 50 pieces of the first sheet of 1 cm in length and 1 cm in width were prepared and immersed.

[0198] The obtained aqueous dispersion of microcapsules was subjected to centrifugal separation at 15,000 rpm for 30 minutes, and the microcapsules were collected. Ethyl acetate was added to the collected microcapsules, and further stirred at 25°C for 24 hours. Then, the obtained solution was filtered, and the obtained residue was subjected to vacuum drying at 60°C for 48 hours to obtain microcapsules that do not contain any substance in the inside (hereinafter, also referred to simply as "measurement material"). That is, the measurement object of the thermal decomposition temperature, that is, the capsule wall material of the microcapsule was obtained.

[0199] Next, the thermal decomposition temperature of the obtained measurement material was measured using a thermogravimetric differential thermal analysis device TG-DTA (device name: DTG-60, manufactured by SHIMADZU CORPORATION). In addition, the thermal decomposition temperature refers to the temperature at which the measurement material is heated from room temperature at a constant heating rate (10°C / min) in a thermal gravimetric analysis (TGA) in an atmospheric environment, and the temperature at which the amount of the measurement material before heating is reduced by 5% by mass is taken as the thermal decomposition temperature (°C).

[0200] The particle diameter of the microcapsule is not particularly limited, and is preferably 1 to 80 μm, more preferably 5 to 70 μm, and even more preferably 10 to 50 μm in terms of the median diameter (D50) on a volume basis.

[0201] The median diameter on a volume basis of the microcapsule can be controlled by adjusting the manufacturing conditions of the microcapsule or the like.

[0202] The median diameter on a volume basis of the microcapsule refers to the diameter at which the total of the volumes of the particles on the large diameter side and the small diameter side becomes equal in the case where the entire microcapsule is divided into two with the particle diameter at which 50% of the volume is accumulated as the threshold. That is, the median diameter corresponds to the so-called D50.

[0203] It is a value calculated by photographing the surface of the first layer of the first sheet having the first layer containing microcapsules at 1000 times by an optical microscope, and measuring the size of all the microcapsules located within a range of 500 μm x 500 μm.

[0204] The number average wall thickness of the capsule wall of the microcapsule is not particularly limited, and is preferably 0.01 to 2 μm, and more preferably 0.05 to 1 μm.

[0205] In addition, the wall thickness of the microcapsule refers to the thickness (μm) of the capsule wall of the capsule particle forming the microcapsule, and the number average wall thickness refers to the average value obtained by measuring the thickness (μm) of each capsule wall of 20 microcapsules by a scanning electron microscope (SEM) and then averaging. More specifically, a cross-section slice of a first sheet having a first layer containing microcapsules is prepared, the cross-section thereof is observed by SEM at 15000 times, and on the basis of any 20 microcapsules having a particle size in the range of (the value of the median diameter on a volume basis of the microcapsules) x 0.9 to (the value of the median diameter on a volume basis of the microcapsules) x 1.1, the cross-section of each of the selected microcapsules is observed, the thickness of the capsule wall is measured, and the average value is calculated.

[0206] The ratio (δ / Dm) of the number average wall thickness δ of the microcapsule to the median diameter on a volume basis (Dm) of the microcapsule is not particularly limited, and is more often 0.005 or more. Among them, from the viewpoint that more precise pressure distribution measurement can be performed at high temperature, it is preferable to satisfy the relationship of formula (1).

[0207] Formula (1) δ / Dm > 0.010

[0208] That is, the above ratio (δ / Dm) is preferably greater than 0.010. Also, the above ratio (δ / Dm) is preferably 0.015 or more. The upper limit is not particularly limited, but is preferably 0.050 or less.

[0209] When the microcapsule satisfies the above formula (1), the balance between the size of the capsule and the thickness of the capsule wall is good, and the possibility of leakage of the contents of the microcapsule or the like under a high temperature environment is less.

[0210] The microcapsule contains a color-developing agent in the inside.

[0211] The color-developing agent refers to a compound that develops color from a colorless state by contact with a color-developing agent described later. As the color-developing agent, an electron-donating dye precursor (a precursor of a colored dye) is preferable. That is, as the color-developing agent, an electron-donating leuco dye is preferable.

[0212] The color former can use a color former known in the use of pressure-sensitive copying paper or heat-sensitive recording paper. As the color former, for example, triphenylmethane phthalide-based compounds, fluoran-based compounds, phenothiazine-based compounds, indolyl phthalide-based compounds, azaindolyl phthalide-based compounds, leucoauramine-based compounds, rhodamine lactam-based compounds, triphenylmethane-based compounds, diphenylmethane-based compounds, triazene-based compounds, spirophthalazine-based compounds, and fluorene-based compounds can be given.

[0213] For the detailed content of the above-mentioned compounds, reference can be made to the description of Japanese Patent Application Laid-Open No. 5-257272.

[0214] The color former can be used alone or in combination of two or more.

[0215] The molecular weight of the color former is not particularly limited, and is usually 300 or more. The upper limit is not particularly limited, and is usually 1000 or less, and from the viewpoint of more excellent effects of the present application, it is preferred to be 600 or less.

[0216] From the viewpoints of visual recognition and heat resistance, the color former is preferably red in color.

[0217] Compared with a blue colorant having an absorption in a long wave (more than about 600 nm), a red colorant having an absorption in a short wave (about 600 nm or less) has a short conjugation, and thus it is considered that it is difficult to change the color even if it is decomposed by heat. Therefore, as a high-temperature use, it is preferred to use a colorant red in color, and more preferably a rhodamine-based color former.

[0218] The molecular weight is usually 300 or more, and when it is a rhodamine-based color former, it is usually 600 or less, and more preferably less than 550.

[0219] As the preferred examples of the color developer, 3-(4-diethylamino-2-ethoxyphenyl)-3-(1-ethyl-2-methylindol-3-yl)-4-azaphthalene, 3-(4-diethylamino-2-ethoxyphenyl)-3-(1-n-octyl-2-methylindol-3-yl)phthalide, 3-[2,2-bis(1-ethyl-2-methylindol-3-yl)vinyl]-3-(4-diethylaminophenyl)-phthalide, 9-[ethyl(3-methylbutyl)amino]spiro[12H-benzo[a]xanthene-12,1'(3'H)isobenzofuran]-3'-one, 2-anilino-6-dibutylaminophthalophane, 6-diethylamino-3-methyl-2-(2,6-dimethylphenylamino)-phthalophane, 2-(2-chloroanilino)-6-dibutylaminophthalophane, 3,3-bis(4-dimethylaminophenyl)-6-dimethylaminophthalide, and 2-anilino-6-diethylamino-3-methylphthalophane, 6'-(diethylamino)-1',3'-dimethylphthalophane, 3',6'-bis(diethylamino)-2-(4-nitrophenyl)spiro[isoindoline-1,9'-xanthene]-3-one, 3,3-bis(2-methyl-1-octyl-3-indol)phthalide, 9-(N-ethyl-N-isopentylamino)spiro[benzo[a]xanthene-12,3'H-phthalide], 2'-methyl-6'-(N-p-tolyl-N-ethylamino)spiro[isobenzofuran-1(3H),9'-[9H]xanthene]-3-one, and 6'-(dibutylamino)-2'-bromo-3'-methylspiro[phthalide-3,9'-xanthene] and the like can be mentioned.

[0220] The microcapsule can contain other components in addition to the color developer described above.

[0221] For example, the microcapsule preferably contains a solvent.

[0222] The solvent is not particularly limited, and examples thereof include alkylnaphthalene compounds such as diisopropyl naphthalene, diarylalkane compounds such as 1-phenyl-1-xylylethane, alkylbiphenyl compounds such as isopropyl biphenyl, triarylmethane compounds, alkylbenzene compounds, benzyl naphthalene compounds, diarylalkylene compounds, arylindane compounds, and aromatic hydrocarbons such as the like; aliphatic hydrocarbons such as phthalate dibutyl and isoparaffin, natural animal and plant oils such as soybean oil, corn oil, cottonseed oil, rapeseed oil, olive oil, coconut oil, castor oil, and fish oil, and natural matter high-boiling distillates such as mineral oil.

[0223] From the viewpoint of improving the solubility of the color developer, the solvent is preferably an aromatic solvent.

[0224] The solvent can be used singly or in combination of two or more.

[0225] The mass ratio of the solvent to the color developer (mass of the solvent / mass of the color developer) in the microcapsule is preferably in the range of 98 / 2 to 30 / 70 from the viewpoint of color development, and more preferably in the range of 97 / 3 to 40 / 60.

[0226] The microcapsule can contain one or more of an ultraviolet absorber, a light stabilizer, an antioxidant, a paraffin, a deodorant, and the like, in addition to the above-mentioned components, as needed.

[0227] As the ultraviolet absorber, a compound having a benzotriazole structure is preferable.

[0228] (Method for producing microcapsule)

[0229] The method for producing the microcapsule containing the color developer is not particularly limited, and known methods such as interfacial polymerization, internal polymerization, phase separation, external polymerization, and coacervation can be mentioned. Among them, the interfacial polymerization is preferable.

[0230] As the interfacial polymerization, an interfacial polymerization including a step of preparing an emulsion by dispersing an oil phase containing a color developer and a capsule wall material (for example, a raw material containing at least one selected from the group consisting of a polyisocyanate, a polyol, and a polyamine. In addition, in the case where a polyamine is produced by reacting a polyisocyanate with water in a reaction system, a polyol and a polyamine can not be used.) in an aqueous phase containing an emulsifier (emulsification step) and a step of polymerizing the capsule wall material at the interface between the oil phase and the aqueous phase to form a capsule wall and form a microcapsule containing the color developer (encapsulation step) is preferable.

[0231] In addition, the mass ratio of the total amount of the polyol and the polyamine to the amount of the isocyanate (total amount of the polyol and the polyamine / amount of the polyisocyanate) in the above-mentioned raw material is not particularly limited, and is preferably in the range of 0.1 / 99.9 to 30 / 70, and more preferably in the range of 1 / 99 to 25 / 75.

[0232] In addition, as the polyisocyanate, the above-mentioned polyisocyanate A and polyisocyanate B can be used together as described above. In the case where both are used together, the preferable range of the mixing ratio of the two is as described above.

[0233] In addition, the type of the emulsifier used in the above-mentioned emulsification step is not particularly limited, and a dispersant and a surfactant can be mentioned.

[0234] As the dispersant, polyvinyl alcohol can be mentioned, for example.

[0235] The content of the microcapsule in the first layer is not particularly limited, and is preferably in the range of 50 to 90% by mass, and more preferably in the range of 55 to 80% by mass, relative to the total mass of the first layer, from the viewpoint of obtaining a color-developed portion having more excellent gradation.

[0236] Furthermore, the content of the colorant in the first layer is not particularly limited, but from the viewpoint of obtaining a color-developing part with better layering, it is preferably 0.1 to 10 g / m. 2 More preferably 0.1–4 g / m 2 .

[0237] (Adhesive)

[0238] The first layer contains an adhesive that supports the microcapsules on the first support.

[0239] The above-mentioned adhesive has an infrared absorption spectrum in the range of 3200–3500 cm⁻¹ -1 Adhesives or cross-linked adhesives that have a peak absorption peak.

[0240] By forming a network using the aforementioned adhesive, excessive adhesion between the first and second sheets can be suppressed even at high temperatures. The adhesive can be as follows: Figure 1 It can also exist in a manner that covers microcapsules, as shown, or as... Figure 3 As shown, part or all of the microcapsule protrudes from the adhesive.

[0241] Here, as an example, it has an infrared absorption spectrum in the range of 3200–3500 cm⁻¹ -1 Adhesives exhibiting a peak absorption value correspond to adhesives having one or more hydrogen-bonding OH groups and hydrogen-bonding NH groups. Generally, adhesives having functional groups selected from OH and NH groups and forming a network through hydrogen bonding of these functional groups exhibit an absorption peak in the infrared spectrum originating from hydrogen-bonding OH groups and / or hydrogen-bonding NH groups, with a peak value in the range of 3200–3500 cm⁻¹. -1 A broad absorption peak with a apex (typically, a half-width of 200 cm⁻¹). -1 (The above absorption peaks). That is, an adhesive having one or more of the hydrogen-bonding OH groups and hydrogen-bonding NH groups refers to an adhesive having one or more functional groups including OH groups and NH groups and forming a network through hydrogen bonding of the OH groups and / or NH groups in the above functional groups.

[0242] Furthermore, in infrared absorption spectra, the peaks of absorption from non-hydrogen-bonded OH and NH groups (i.e., OH and NH groups that do not contribute to hydrogen bonding) typically occur between 3650 and 3584 cm⁻¹. -1 As shown in the image, the absorption peak is sharp (typically, the full width at half maximum is less than 200 cm⁻¹). -1 ).

[0243] The order of infrared absorption spectroscopy measurements for adhesives is as follows.

[0244] First, the first sheet is immersed in hot water at 80 to 95°C for 0.5 to 2 hours to separate the microcapsules from the binder. Next, the water of the hot water extract is removed, and the powder sample is subjected to infrared absorption spectrum measurement using the KBr method and using an infrared spectrophotometer (e.g., FTS7000, manufactured by Digilab).

[0245] From the obtained infrared absorption spectrum, it is determined whether or not there is an absorption peak having a peak top at 3200 to 3500 cm -1 an absorption peak having a peak top at 3200 to 3500 cm -1 the above absorption peak).

[0246] In addition, as described above, the binder of the first layer can be a cross-linked binder.

[0247] For the determination of whether or not the binder is a cross-linked binder, the first sheet is immersed in hot water at 80 to 95°C for 0.5 to 2 hours, and after the immersion, the film weight is measured after sufficient drying. When the reduction rate of the film weight is 5% or less, it is determined that the binder is a cross-linked binder.

[0248] Hereinafter, first, a binder having an absorption peak having a peak top at 3200 to 3500 cm -1 an absorption peak having a peak top at 3200 to 3500 cm

[0249] As described above, the binder A is a binder having one or more of a hydrogen-bonding OH group and a hydrogen-bonding NH group. As the binder A, one or two or more resins having one or more functional groups including the OH group and the NH group are preferably configured as follows: a network is formed by hydrogen bonding of the OH group and / or the NH group among the above functional groups.

[0250] As the above functional groups, for example, -OH, -NH2, -NHR (R represents an aromatic or aliphatic hydrocarbon), -COOH, -CONH2, -NHOH, -SO3H, -OP(=O)OH2, -CO-NH-, -NH-, -CO-NH-CO-, and -NH-NH-, and the like can be given, and from the viewpoint of the effects of the present application being more excellent, among these, -OH (hydroxyl group) or -CO-NH- (amide bond) is preferred. That is, the binder A is preferably a resin including -OH (hydroxyl group) or -CO-NH- (amide bond).

[0251] Further, from the viewpoint of more excellent effects of the present application, the higher the compatibility of the adhesive in the first layer with the resin X1 contained in the adhesive layer is, the more preferable it is. As a preferred one of the first sheet, when the adhesive A contains a resin having one or more of a hydroxyl group and an amide bond, the adhesive layer preferably includes the resin X1 containing an aromatic group and the resin X2 having one or more of an amide bond and a hydroxyl group. Further, when the adhesive layer contains the resin X1 and the resin X2, the resin X1 and the resin X2 can form a mixed layer within the adhesive layer, and it is preferable that a layer containing the resin X1 and a layer containing the resin X2 are formed within the adhesive layer, respectively (in other words, the adhesive layer can have a layer containing the resin X1 and a layer containing the resin X2). Further, when it is the latter, it is preferable that they are arranged in the order of the first support, the layer containing the resin X1, the adhesive layer containing the resin X2, and the first layer.

[0252] As the resin having the above-mentioned functional group, from the viewpoint of more excellent effects of the present application, it is preferable that it is selected from at least one of a cellulose-based resin, a polyamide, and a polyvinyl alcohol.

[0253] As specific examples of the adhesive A, carboxymethyl cellulose, carboxyethyl cellulose, methyl cellulose, ethyl cellulose, hydroxymethyl cellulose, hydroxyethyl cellulose, methylhydroxypropyl cellulose, hydroxypropylmethyl cellulose, crystalline cellulose, xanthan gum, guar gum, hydroxyethyl guar gum, carboxymethyl guar gum, tragacanth gum, locust bean gum, gum ghatti, psyllium seed, carrageenan, polygalactose, gum arabic, pectin, polytriglucose, mannan, glucomannan, starch, curdlan, carrageenan, chondroitin sulfate, dermatan sulfate, glycogen, heparan sulfate, hyaluronic acid, keratan sulfate, chondroitin, mucin sulfate, dextran, keratan sulfate, succinoglucan, gellan gum, alginic acid, propylene glycol alginate, polyethylene glycol, chitin, chitosan, carboxymethyl chitin, gelatin, casein, arabic gum, junctin, curdlan, polyvinyl alcohol, carboxyvinyl polymer, alkyl-modified carboxyvinyl polymer, poly(meth)acrylic acid, and acrylic acid / methacrylic acid alkyl copolymer, and the like can be given. Further, as for the compound having an acid group such as a carboxyl group, a part or all thereof can be a salt such as a sodium salt, a potassium salt, or an ammonium salt.

[0254] Further, the adhesive A can be a structure in which a part or all thereof is crosslinked by a crosslinking agent.

[0255] As the crosslinking agent, for example, water-soluble initial condensates such as N-hydroxymethyl urea, N-hydroxymethyl melamine, and urea-formalin; dialdehyde compounds such as glyoxal and glutaraldehyde; inorganic crosslinking agents such as boric acid and borax; and polyamide epichlorohydrin, and the like can be given.

[0256] The top height of the absorption peak derived from the hydrogen-bonding OH group and the hydrogen-bonding NH group in the infrared absorption spectrum of the adhesive A is preferably the first to third highest among the peak heights of other absorption peaks observed in other regions than the wave number region of 3200 to 3500 cm -1 -1- to the third highest. That is, when the adhesive A has five absorption peaks in the infrared absorption spectrum, the peak height of the absorption peak derived from the hydrogen-bonding OH group and the hydrogen-bonding NH group is preferably the highest, the second highest, or the third highest among the peak heights of the five absorption peaks. When the infrared absorption spectrum of the adhesive A exhibits the above-described characteristics, the effects of the present application are more excellent.

[0257] Next, a crosslinked adhesive (hereinafter also referred to as "adhesive B") will be described.

[0258] As the adhesive B, a crosslinked adhesive obtained by ultraviolet curing of a water-soluble (meth)acrylamide or a water-soluble (meth)acrylate, a crosslinked adhesive obtained by crosslinking reaction of a water-dispersible isocyanate, and a crosslinked adhesive obtained by reaction of an alkoxysilane by sol-gel method, and the like can be given.

[0259] As the water-soluble (meth)acrylamide, at least one of a monofunctional (meth)acrylamide and a polyfunctional (meth)acrylamide is preferred.

[0260] As the water-soluble (meth)acrylate, at least one of a monofunctional (meth)acrylate and a polyfunctional (meth)acrylate is preferred.

[0261] As the water-dispersible isocyanate, use with a polyol is preferred.

[0262] Further, when an ultraviolet-curable crosslinked adhesive is used, use with a photopolymerization initiator (preferably a radical polymerization initiator) is preferred.

[0263] The content of the adhesive in the first layer is not particularly limited, and from the viewpoint of more excellent effects of the present application, 5 to 40% by mass, more preferably 10 to 20% by mass, relative to the total mass of the first layer is preferred.

[0264] Further, the content of the adhesive in the first layer is not particularly limited, and from the viewpoint of more excellent effects of the present application, 0.2 to 3.0 g / m 2 , more preferably 0.5 to 1.5 g / mw is preferred.

[0265] Further, as the melting point (atmospheric pressure) of the adhesive in the first layer, 180°C or higher, more preferably 200°C or higher is preferred. In addition, the upper limit value is not particularly limited, and for example, 600°C or lower is preferred.

[0266] (Other components)

[0267] The first layer can contain other components in addition to the microcapsules described above.

[0268] As the other components, for example, release agents (e.g., inorganic fillers such as colloidal silica and silicones), fluorescent brightening agents, antifoaming agents, penetrants, ultraviolet absorbers, surfactants, and preservatives can be mentioned.

[0269] As the surfactants, for example, anionic surfactants, nonionic surfactants, and cationic surfactants can be mentioned, but from the viewpoint of maintaining the dispersibility of the microcapsules, anionic surfactants or nonionic surfactants are preferred.

[0270] Further, as the surfactants, fluorine-based surfactants, silicone-based surfactants, hydrocarbon-based surfactants, and the like can be mentioned, and from the viewpoint of maintaining the coatability or the dispersibility of the microcapsules, hydrocarbon-based surfactants are preferred.

[0271] The content of the surfactants is not particularly limited, and is preferably 0.01 to 10% by mass, more preferably 0.1 to 5% by mass, relative to the total mass of the first layer.

[0272] The release agent is preferably introduced after the first sheet and the second sheet are overlapped and the heating pressure is measured, in order to make the two easily peelable. From the viewpoint of making the first sheet and the second sheet easily peelable, the release agent is preferably an inorganic filler, of which silica particles or alumina particles are preferred. The median diameter of the inorganic filler is preferably 0.001 to 1 μm, more preferably 0.005 to 0.1 μm, and further preferably 0.005 to 0.05 μm.

[0273] The content of the inorganic filler is preferably 1 to 50% by mass, preferably 3 to 30% by mass, and more preferably 5 to 20% by mass, relative to the total mass of the first layer.

[0274] The lower limit value of the thickness of the first layer is 0.2 μm or more, and from the viewpoint of the effects of the present application being more excellent, 0.3 μm or more is preferred. Further, the upper limit value of the thickness of the first layer is, for example, preferably 5 μm or less, and from the viewpoint of the gradation of the color-developed portion formed by pressure being more excellent, 1.0 μm or less is more preferred, and 0.7 μm or less is further preferred.

[0275] Here, the thickness of the first layer indicates the thickness of the microcapsules other than the microcapsules exposed from the surface of the layer, in the case where the diameter of the microcapsules is larger than the thickness of the layer. For example, when the pressure-measuring sheet set shown in Figure 1 is used, the thickness of the layer refers to the thickness T1 other than the microcapsules exposed from the surface of the layer. Further, for example, when the microcapsules and the binder become as shown in Figure 3When configured as shown, the layer thickness refers to the thickness T2 excluding the microcapsules exposed from the surface of the layer.

[0276] In the present specification, as a method of measuring the thickness of the first layer, cross-sectioned pieces are subjected to SEM observation, the thickness of any 5 sites in the layer is measured, and the average thereof is calculated.

[0277] The thickness of the first layer is preferably smaller than the median diameter (D50) of the microcapsules. The thickness of the first layer relative to the median diameter (D50) of the microcapsules is preferably 0.1 to 50%, and preferably 0.5 to 25%. The thinner the thickness of the first layer relative to the microcapsules, the more pressure is applied to the microcapsules rather than the adhesive, and thus the microcapsules are easily damaged, and the pressure range can be adjusted according to the measurement.

[0278] Furthermore, the mass per unit area (g / m2) of the first layer is not particularly limited, and is preferably 0.5 to 20 g / m2. 2 2

[0279] From the viewpoint of being suitable for pressure measurement in the low-pressure field, the arithmetic average roughness Ra of the surface on the side opposite to the first support of the first layer is preferably 2 μm or more, and more preferably 4.1 μm or more. The upper limit value is not particularly limited, and is preferably 10 μm or less.

[0280] In the case of using the pressure measurement sheet set, the arithmetic average roughness Ra of the first layer in the present embodiment is the arithmetic average roughness Ra of the surface on the side (the side in contact) opposite to the second sheet of the first layer.

[0281] The arithmetic average roughness Ra of the first layer in the present specification refers to the arithmetic average roughness Ra defined in JIS B 0681-6:2014. As a measuring device for the arithmetic average roughness Ra, a scanning white light interferometer using an optical interference method (specifically, NewView 5020: Stich mode; objective lens x 50 times; intermediate lens x 0.5 times, manufactured by Zygo Corporation) is used.

[0282] In the case where the arithmetic average roughness Ra of the first layer is the above lower limit value or more, the color developer is in a sufficient amount, and thus the microcapsules are easily damaged even at low pressure, and thus a higher color development density is easily obtained. On the other hand, in the case where the arithmetic average roughness Ra of the first layer is the above upper limit value or less, in the pressurized region, the second layer of the second sheet can appropriately absorb the solvent that flows out together with the color developer by the disintegration of the microcapsules, and thus a good quality with less bleeding is easily obtained.

[0283] The arithmetic average roughness Ra of the first layer can be controlled by adjusting the solid content coating amount of the first layer-forming composition and adjusting the amount of the microcapsules in the first layer.​​

[0284] (Manufacturing method of the first sheet)

[0285] The manufacturing method of the first sheet is not particularly limited, and for example, a manufacturing method having the following process 1 and process 2 is preferred.

[0286] Process 1: A process of forming the above-mentioned adhesive layer by applying a composition containing a resin X1 having at least one group selected from the group consisting of an aromatic group, an ester bond, and an imide bond (hereinafter also referred to as "adhesive layer-forming composition") on the first support.

[0287] Process 2: A process of forming the above-mentioned first layer having a thickness of 0.2 μm or more by applying one composition selected from the following composition A and composition B (hereinafter also referred to as "first layer-forming composition") on the above-mentioned adhesive layer.

[0288] Composition A: A composition containing a microcapsule containing a color developer and a component for forming an adhesive having any one or more of a hydrogen-bonding OH group and a hydrogen-bonding NH group.

[0289] Composition B: A composition containing a microcapsule containing a color developer and a component for forming a crosslinked adhesive.

[0290] In addition, the structures of the first support, the resin X1, the microcapsule, and the adhesive used in each of the above-mentioned processes are as described above.

[0291] The method of applying the adhesive layer-forming composition and the first layer-forming composition is not particularly limited, and as the coater used at the time of application, for example, an air-knife coater, a rod coater, a bar coater, a curtain coater, a gravure coater, a squeeze coater, a die coater, a slide bead coater, and a doctor blade coater can be mentioned.

[0292] After the adhesive layer-forming composition and the first layer-forming composition are applied to the adhesive layer, drying treatment can be performed on the coating film as necessary. As the drying treatment, heating treatment can be mentioned.

[0293] Further, when the first layer-forming composition is composition B and the component for forming the crosslinked adhesive contained in the composition B is a photocurable component, it is preferred to further apply exposure treatment to the coating film of the first layer-forming composition (the coating film after drying treatment can also be mentioned). In addition, the exposure light source is not particularly limited, and for example, ultraviolet rays and the like can be mentioned.

[0294] The adhesive layer-forming composition preferably contains at least the resin X1 having at least one group selected from the group consisting of an aromatic group, an ester bond, and an imide bond and a solvent.

[0295] The composition A preferably contains at least the microcapsules, a component for forming a binder having at least one of a hydrogen-bonding OH group and a hydrogen-bonding NH group, and a solvent.

[0296] As one mode of the component for forming a binder having at least one of a hydrogen-bonding OH group and a hydrogen-bonding NH group, for example, a resin having a functional group including at least one of an OH group and an NH group can be given (in addition, the OH group and the NH group included in the above-mentioned resin can become a hydrogen-bonding OH group and a hydrogen-bonding NH group by hydrogen bonding within and / or between the resins).

[0297] Further, as another mode of the component for forming a binder having at least one of a hydrogen-bonding OH group and a hydrogen-bonding NH group, a combination of a resin having a functional group including at least one of an OH group and an NH group and a crosslinking agent can be given (in addition, the OH group and the NH group included in the above-mentioned resin can become a hydrogen-bonding OH group and a hydrogen-bonding NH group by hydrogen bonding within and / or between the resins).

[0298] As the resin having a functional group including at least one of an OH group and an NH group and the crosslinking agent, the above-mentioned can be given.

[0299] In addition, a mixture of the microcapsule dispersion liquid obtained by the above-mentioned interfacial polymerization method and the component for forming a binder having at least one of a hydrogen-bonding OH group and a hydrogen-bonding NH group can be used as the composition A.

[0300] Other components that can be included in the above-mentioned first layer can also be included in the composition A.

[0301] The composition B preferably contains at least the microcapsules, a component for forming a crosslinking binder, and a solvent.

[0302] As one mode of the component for forming a crosslinking binder, water-soluble (meth)acrylamide, water-soluble (meth)acrylate, water-dispersible isocyanate, and alkoxy silane, etc. can be given.

[0303] In addition, when the composition B contains a water-dispersible isocyanate, the composition B preferably further contains a polyol.

[0304] Further, a mixture of the microcapsule dispersion liquid obtained by the above-mentioned interfacial polymerization method and the component for forming a crosslinking binder can be used as the composition B.

[0305] Further, when the composition B uses water-soluble (meth)acrylamide and water-soluble (meth)acrylate (ultraviolet-curable monomer), the composition B preferably further contains a photopolymerization initiator (preferably a radical polymerization initiator).

[0306] The composition B can also contain other components that can be contained in the above-mentioned first layer.

[0307] As the solvent that can be contained in the composition A and the composition B, for example, water can be mentioned.

[0308] <<Second sheet>>

[0309] Figure 1 The second sheet 22 described in the above has a second support 18 and a second layer 20 containing a color developer disposed on the second support 18.

[0310] With respect to the second sheet 22, when heated at 220°C for 10 minutes, the shrinkage S1 in the length direction of the second sheet 22 and the shrinkage S2 in the width direction orthogonal to the length direction of the second sheet 22 are preferably both -0.5 to 3.0%, and more preferably 1.0 to 3.0% from the viewpoint of more excellent effects of the present application.

[0311] The absolute value of the difference between the shrinkage S1 and the shrinkage S2 of the second sheet 22 is preferably the same range as the absolute value of the difference between the shrinkage S1 and the shrinkage S2 of the first sheet 16.

[0312] With respect to the measurement method of the shrinkage S1 and the shrinkage S2 of the second sheet 22, the same method as the measurement method of the shrinkage S1 and the shrinkage S2 of the first sheet 16 is used except that the second sheet 22 is used instead of the first sheet 16.

[0313] With respect to the definition of the length direction and the width direction in the second sheet 22, the same definition as the definition of the length direction and the width direction of the first sheet 16 is used except that the first sheet 16 is changed to the second sheet 22.

[0314] The second sheet 22 can be a single leaf (single sheet) or can be in a long strip shape.

[0315] Hereinafter, each component will be described in detail.

[0316] <Second support>

[0317] The second support is a component for supporting the second layer.

[0318] Since the second support is the same as the first support described above, the description is omitted.

[0319] <Second layer>

[0320] The second layer is a layer containing a color developer.

[0321] The color developer refers to a compound that has no coloring function by itself but has a property of causing a color developer to color by contacting the color developer. As the color developer, an electron-accepting compound is preferable.

[0322] As the color developer, inorganic compounds and organic compounds can be given.

[0323] As the inorganic compound, for example, clay substances such as acid clay, activated white clay, attapulgite, zeolite, bentonite, and kaolin can be given.

[0324] As the organic compound, for example, metal salts of aromatic carboxylic acids, metal salts of phenol-formaldehyde resins, and metal salts of carboxylated terpene phenol resins can be given.

[0325] As the metal salt of aromatic carboxylic acid, zinc salts, nickel salts, aluminum salts, or calcium salts of 3,5-di-tert-butylsalicylic acid, 3,5-di-tert-octylsalicylic acid, 3,5-di-tert-nonylsalicylic acid, 3,5-di-tert-dodecylsalicylic acid, 3-methyl-5-tert-dodecylsalicylic acid, 3-tert-dodecylsalicylic acid, 5-tert-dodecylsalicylic acid, 5-cyclohexylsalicylic acid, 3,5-bis (α, α-dimethylbenzyl) salicylic acid, 3-methyl-5- (α-methylbenzyl) salicylic acid, 3- (α, α-dimethylbenzyl) -5-methylsalicylic acid, 3- (α, α-dimethylbenzyl) -6-methylsalicylic acid, 3- (α-methylbenzyl) -5- (α, α-dimethylbenzyl) salicylic acid, 3- (α, α-dimethylbenzyl) -6-ethylsalicylic acid, 3-phenyl-5- (α, α-dimethylbenzyl) salicylic acid, salicylic acid resins of carboxyl-modified terpene phenol resins, and reaction products of 3,5-bis (α-methylbenzyl) salicylic acid and benzyl chloride, and the like can be given.

[0326] Among them, as the color developer, clay substances, metal salts of aromatic carboxylic acids, or metal salts of carboxylated terpene phenol resins are preferable, clay substances or metal salts of aromatic carboxylic acids are more preferable, and clay substances are further preferable, and acid white clay, activated white clay, or kaolin is particularly preferable.

[0327] In particular, when clay substances are used as the color developer, the clay substances are less likely to discolor when the pressure distribution is measured at high temperatures, and thus the display quality of the pressure distribution in the sheet set for pressure measurement is excellent.

[0328] The content of the color developer in the second layer is not particularly limited, and is preferably 20 to 95 mass%, and more preferably 30 to 90 mass%, relative to the total mass of the second layer, from the viewpoint of being able to perform more precise pressure distribution measurement at high temperatures.

[0329] The content of the color developer in the second layer is not particularly limited, and is preferably 0.1 to 30 g / m 2 When the color developer is an inorganic compound, the content of the color developer is preferably 3 to 20 g / m 2 , and more preferably 5 to 15 g / m 2In the case where the color developer is an organic compound, the content of the color developer is preferably 0.1 to 5 g / m2, more preferably 0.2 to 3 g / m2. 2 .

[0330] The second layer can contain other components in addition to the color developer described above.

[0331] As the other components, for example, a high-molecular binder, a pigment, a fluorescent whitening agent, an antifoaming agent, a penetrant, an ultraviolet absorber, a surfactant, and a preservative can be mentioned.

[0332] As the high-molecular binder, for example, a synthetic high-molecule such as a styrene-butadiene copolymer, a polyvinyl acetate, a polyacrylate, a polyvinyl alcohol, a polyacrylic acid, a maleic anhydride-styrene copolymer, starch, casein, gum arabic, gelatin, carboxymethyl cellulose, and methyl cellulose, or a natural high-molecule such as calcium carbonate, light calcium carbonate, talc, and titanium dioxide can be mentioned.

[0333] As the pigment, for example, heavy calcium carbonate, light calcium carbonate, talc, and titanium dioxide can be mentioned.

[0334] The thickness of the second layer is not particularly limited, and is preferably 1 to 50 μm, more preferably 2 to 30 μm, from the viewpoint that more precise pressure distribution measurement can be performed at a high temperature.

[0335] Further, the mass per unit area (g / m2) of the second layer is not particularly limited, and is preferably 0.5 to 20 g / m2. 2 ) is not particularly limited, and is preferably 0.5 to 20 g / m 2 .

[0336] <Method for forming the second layer>

[0337] The method for forming the second layer described above is not particularly limited, and a publicly known method can be mentioned.

[0338] For example, a method in which a second layer-forming composition containing a color developer is applied to a second support, and drying treatment is performed as necessary can be mentioned.

[0339] The second layer-forming composition can be a dispersion liquid in which a color developer is dispersed in water or the like. In the case where the color developer is an inorganic compound, a dispersion liquid in which the color developer is dispersed can be prepared by mechanically dispersing the inorganic compound in water. Further, in the case where the color developer is an organic compound, it can be prepared by mechanically dispersing the organic compound in water or dissolving it in an organic solvent.

[0340] The second layer-forming composition can also contain other components that can be contained in the second layer described above.

[0341] The method of coating the composition for forming the second layer is not particularly limited, and a method using a coater used when coating the composition for forming the first layer described above can be mentioned.

[0342] After the composition for forming the second layer is coated on the second support, drying treatment can be performed on the coated film as needed. As the drying treatment, heating treatment can be mentioned.

[0343] In addition, although the method of forming the second layer on the second support has been described above, it is not limited to the above-described manner, and for example, the second layer can be formed on a temporary support, and the temporary support can be peeled off, thereby forming a second sheet formed of the second layer.

[0344] As the temporary support, as long as it is a support that is peelable, it is not particularly limited.

[0345] <Other components>

[0346] The second sheet can have other components in addition to the second support and the second layer described above.

[0347] For example, the second sheet can have an adhesive layer between the second support and the second layer for improving the adhesion of the two.

[0348] The adhesive layer can be of a type that the first sheet described above can have.

[0349] <Preferred Mode 1 of the Pressure Measurement Sheet Set of the First Embodiment>

[0350] From the viewpoint of more excellent effects of the present application, the pressure measurement sheet set of the first embodiment is preferably one that satisfies any of the conditions (A) to (C) shown below.

[0351] (A) The first sheet is one in which the shrinkage rate S1 in the length direction at the time of heating for 10 minutes at 220°C is 1.0 to 3.0%, and the first support is one in which polyethylene naphthalate is contained at a rate of 70% by mass or more with respect to the total mass of the sheet.

[0352] (B) The first support and the second support are ones in which the thickness is 70 μm or more and polyethylene naphthalate is contained at a rate of 70% by mass or more with respect to the total mass of the sheet.

[0353] (C) The first support and the second support are ones in which an aromatic polyimide sheet is used.

[0354] In addition, regarding the sheet in which polyethylene naphthalate is contained at a rate of 70% by mass or more with respect to the total mass of the sheet, as described above.

[0355] Further, when the above condition (A) is satisfied, the thickness of the first support and the second support is not particularly limited, and is preferably 50 μm or more, for example.

[0356] Further, when the above condition (B) is satisfied, the shrinkage rate S1 of the first sheet and the second sheet in the longitudinal direction at the time of heating for 10 minutes at 220°C is preferably -0.5 to 3.0%.

[0357] <<Preferred Mode 2 of the Pressure Measuring Sheet Set of the First Embodiment>>

[0358] As described above, the first sheet and the second sheet are stacked with the first layer of the first sheet and the second layer of the second sheet facing each other to obtain a laminate, and the laminate is used by being subjected to pressurization. That is, the first sheet corresponds to a sheet for measuring pressure together with the above second sheet.

[0359] L of the color-developed portion of the laminate when color development is performed by applying pressure thereto * a * b * The chroma in the color system is not particularly limited, but from the viewpoint of easily visually recognizing color development, the chroma a * is preferably greater than 30 and 80 or less, and the chroma b * is preferably greater than -50 and 50 or less.

[0360] Further, when the above chroma is measured, the first sheet and the second sheet of the laminate after pressure application are peeled, and the chroma of the color-developed portion of the second sheet is measured using a densitometer RD-19 (manufactured by GRETAG MACBETH). When the second sheet includes a transparent second support, the chroma measurement of the color-developed portion is performed from the second support side.

[0361] [Use]

[0362] The pressure measuring sheet set of the present application can be used for various uses, for example, in the verification or management of various manufacturing processes including high-temperature hot pressing in the process. More specifically, the confirmation of pressure distribution in the lamination process in the field of batteries (lithium ion batteries, fuel cells), the confirmation of pressure distribution in the lamination process in the field of printed circuit boards (FPC, BWB), the confirmation of pressure distribution in the hot press bonding process such as ACF bonding and lamination of the wiring lead-out portion, and the confirmation of pressure distribution of the mold fastening portion can be cited.

[0363] [Manufacturing method of pressure measuring sheet]

[0364] The manufacturing method of the pressure measuring sheet is not particularly limited, and is preferably a manufacturing method including the manufacturing method of the above first sheet. Further, the manufacturing method of the first sheet is as described above.

[0365] Examples

[0366] Hereinafter, the present application will be further explained based on examples. The materials, amounts used, ratios, processing contents, processing sequences and the like shown in the following examples can be appropriately changed as long as the gist of the present application is not deviated. Thus, the scope of the present application should not be interpreted limitatively by the examples shown below.

[0367] Further, the following "parts" and "%" are based on mass unless otherwise specified.

[0368] Further, the abbreviations in the following example columns are as described below.

[0369] St: styrene

[0370] MMA: methyl methacrylate

[0371] MAA: methacrylic acid

[0372] PMMA: polymethyl methacrylate

[0373] [Preparation of microcapsules containing a color-developing agent]

[0374] Each of the microcapsules containing a color-developing agent used in the examples and comparative examples was prepared by the following procedure. Further, the thermal decomposition temperature of the capsule wall of the microcapsules containing a color-developing agent A to C was 250°C or higher. Further, the measuring method of the thermal decomposition temperature was as described above.

[0375] [Preparation of microcapsules containing a color-developing agent A]

[0376] In 50 parts of 1,1-diphenylethane (manufactured by JXTG Energy Co., Ltd., SAS-296), 3 parts of 3',6'-bis(diethylamino)-2-(4-nitrophenyl)spiro[isoindoline-l,9'-xanthene]-3-one (manufactured by Hodogaya Chemical Co., Ltd., Pink-DCF), 4 parts of 6'-(diethylamino)-l',3'-dimethylfluoran (manufactured by Hodogaya Chemical Co., Ltd., Orange-DCF) and 3 parts of 2-(2'-hydroxy-5'-methylphenyl)benzotriazole (JOHOKU CHEMICAL CO., LTD, JF-77-P) were dissolved as a color-developing agent and an ultraviolet absorber, respectively, to obtain a solution A.

[0377] Next, isoparaffin (Idemitsu Kosan Co., Ltd., IPSolvent 1620) 13 parts was added to the stirred solution A to obtain solution B. Further, trimethylolpropane adduct of toluene diisocyanate (DIC Corporation, Barnock D-750, solid content concentration 75 mass%) 1.6 parts dissolved in ethyl acetate 6 parts and MILLIONATE MR-200 (TOSOH CORPORATION 3.7 parts were added to the stirred solution B to obtain solution C. In addition, MILLIONATE MR-200 is a mixture of diphenylmethane diisocyanate and polymethylene polyphenyl polyisocyanate. Furthermore, the above-mentioned solution C was added to a solution in which polyvinyl alcohol (JP-45, Japan Vam & Poval Co., Ltd.) 4 parts was dissolved in water 140 parts, and emulsion dispersion was performed. To the emulsion after emulsion dispersion, water 200 parts was added, and while stirring, it was warmed to 70°C, and after stirring for 1 hour, cooling was performed. Further, water was added to adjust the concentration, and thus, the inside colorant-containing microcapsule A liquid having a solid content concentration of 25% was obtained.

[0378] [Preparation of inside colorant-containing microcapsule B]

[0379] In addition to adjusting the particle diameter by adjusting the stirring conditions, the inside colorant-containing microcapsule B liquid was prepared in the same manner as in [Preparation of inside colorant-containing microcapsule A].

[0380] [Preparation of inside colorant-containing microcapsule C]

[0381] In addition to changing the material used for the capsule wall to melamine and formaldehyde and forming the capsule wall by a publicly known method, the inside colorant-containing microcapsule C liquid was prepared in the same manner as in [Preparation of inside colorant-containing microcapsule A].

[0382] [Preparation of inside colorant-containing microcapsule D]

[0383] Referring to

[0153] of WO2020 / 149410A, the inside colorant-containing microcapsule D liquid having a capsule wall was prepared using trimethylolpropane adduct of toluene diisocyanate (DIC Corporation, Barnock D-750) and N,N,N',N'-tetrakis(2-hydroxypropyl)ethylenediamine. In addition, the capsule wall of the inside colorant-containing microcapsule D corresponds to polyurethane urea 2 in Table 1.

[0384] [Preparation of inside colorant-containing microcapsule E]

[0385] Referring to

[0091] of WO2018 / 062017A, the color developing agent- containing microcapsule E liquid in which a toluene diisocyanate trimethylolpropane adduct (DIC Corporation, Barnock D-750) and N,N,N',N'-tetrakis(2-hydroxypropyl)ethylenediamine were used to form the capsule wall was prepared. In addition, the capsule wall of the color developing agent-containing microcapsule E corresponds to the polyurethane urea 3 in Table 1.

[0386] [Example 1]

[0387] [Preparation of the sheet set for pressure measurement]

[0388] [Preparation of the substrates of the first sheet and the second sheet]

[0389] On a polyethylene naphthalate sheet (PEN) (Teijin Film Solutions Limited, Theonex (registered trademark) Q51 (corresponding to "the first support body")) having a thickness of 75 μm, an adhesive layer-forming composition having a styrene butadiene latex (SBR) was applied and dried to form an adhesive layer having a thickness of 0.1 μm. The obtained substrate (support body with adhesive layer) was used in the preparation of the first sheet of Example 1 described later. Also, as for the substrate of the second sheet, the same substrate as that of the first sheet was prepared and used.

[0390] In addition, in the sheet set for pressure measurement of each of the examples and comparative examples of Table 2, the same substrate was used for the substrate of the first sheet and the substrate of the second sheet. Therefore, the support body and the adhesive layer in the substrate of the first sheet and the support body and the adhesive layer in the substrate of the second sheet were respectively the same.

[0391] [Preparation of the first sheet]

[0392] The color developing agent-containing microcapsule A liquid (43 parts by mass), water (15 parts by mass), colloidal silica (NISSAN CHEMICAL CORPORATION, SNOWTEX (registered trademark) 30, solid content 30%) as a releasing agent (5.7 parts by mass), a 10% by mass aqueous solution of POLYMARON 482 (Arakawa Chemical Industries, Ltd.) (1.8 parts by mass), a 10% by mass aqueous solution of carboxymethyl cellulose Na (24 parts by mass), a 1% by mass aqueous solution of RAPISOL A-90 (NOF CORPORATION) (0.7 parts by mass), and a 1% by mass aqueous solution of NOIGEN LP-70 (DKS Co. Ltd., polyoxyethylene alkyl ether-based surfactant) (0.7 parts by mass) were mixed, and a first layer-forming composition was obtained by stirring for 2 hours.

[0393] A first layer forming composition was applied to the adhesive layer of the above-mentioned substrate using a bar coater, and heat-dried to form a first layer of about 0.2 μm, thereby producing a first sheet.

[0394] <Production of a second sheet>

[0395] A dispersion liquid was prepared by dispersing active white clay treated with sulfuric acid (200 parts by mass), sodium hexametaphosphate (1 part by mass), 10% by mass sodium hydroxide aqueous solution (30 parts by mass), and water (290 parts by mass) so that the average particle diameter of all particles became 2 μm using a sand mill.

[0396] Next, a coating liquid containing a color developer was prepared by mixing 19% by mass of a water dispersion liquid of Nipol LX-814 (Zeon Corporation) (180 parts by mass), 3.3% by mass of an aqueous solution of POLYMARON 482 (Arakawa Chemical Industries, Ltd.) (220 parts by mass), 1% by mass of an aqueous solution of carboxymethyl cellulose Na (DKS Co., Ltd., SEROGEN EP) (80 parts by mass), 15% by mass of an aqueous solution of sodium alkylbenzenesulfonate (DKS Co., Ltd., NEOGEN T) (4.7 parts by mass), and 1% by mass of an aqueous solution of NOIGEN LP70 (DKS Co., Ltd.) (70 parts by mass) in the prepared dispersion liquid.

[0397] The coating liquid containing a color developer was applied to the adhesive layer of the above-mentioned substrate so that the solid content application amount became 12.0 g / m 2 , and dried to form a second layer, thereby obtaining a second sheet.

[0398] [Examples 2 to 12]

[0399] Examples 2 to 11 were produced in the same manner as Example 1 except that the structures described in Table 1 were changed.

[0400] In addition, the first support and the second support used in Example 10 were sheets formed of PI (polyimide). Furthermore, the first support and the second support used in Example 11 were sheets formed of a PEN / PET (polyethylene terephthalate) copolymer (mass ratio: 70 / 30). Furthermore, the first support and the second support used in Example 12 were sheets formed of a PEN / PET copolymer (mass ratio: 50 / 50).

[0401] [Example 13]

[0402] [Production of a substrate of a first sheet and a second sheet]

[0403] On a polyethylene naphthalate sheet (PEN) of 75 μm in thickness (Teijin Film Solutions Limited, Theonex (registered trademark) Q51 (corresponding to "the first support.")), a first adhesive layer-forming composition having styrene butadiene latex (SBR) was applied and dried to form a first adhesive layer of 0.1 μm in thickness. Subsequently, on the obtained first adhesive layer, a second adhesive layer-forming composition having gelatin was applied and dried to form a second adhesive layer of 0.5 μm in thickness. That is, an adhesive layer containing styrene butadiene latex (SBR) and gelatin was formed. Also, as to the substrate of the second sheet, the same substrate as that of the first sheet was prepared and used.

[0404] A sheet set for pressure measurement was prepared in the same manner as in Example 5, except that the substrates of the first and second sheets were changed to the above-described substrates.

[0405] [Examples 14 to 16]

[0406] A sheet set for pressure measurement was prepared in the same manner as in Example 5, except that the resin in the adhesive layer-forming composition was changed to the resin described in Table 1 and the thickness of the adhesive layer was changed to the thickness shown in Table 1.

[0407] In addition, in Example 14, St / MMA / MAA was a copolymer of 40 / 40 / 20 (mass ratio).

[0408] [Example 17]

[0409] A sheet set for pressure measurement was prepared in the same manner as in Example 15, except that, in the preparation of the first sheet, the kind of the microcapsules containing a color developer was changed to the kind described in Table 1 and 24 parts by mass of carboxymethyl cellulose Na (10 mass% aqueous solution) in the first layer-forming composition was changed to 24 parts by mass of polyvinyl alcohol (PVA) (10 mass% aqueous solution), except that.

[0410] [Example 18]

[0411] A sheet set for pressure measurement was prepared in the same manner as in Example 15, except that, in the preparation of the first sheet, 24 parts by mass of carboxymethyl cellulose Na (10 mass% aqueous solution) in the first layer-forming composition was changed to 22 parts by mass of PVA (10 mass% aqueous solution) and 0.5 parts by mass of a crosslinking agent (glyoxal (39 mass% aqueous solution, Tokyo Chemical Industry Co., Ltd.)), except that.

[0412] [Example 19]

[0413] A pressure measurement sheet set was produced in the same manner as in Example 17, except that the resin in the adhesive layer-forming composition was changed to the resin described in Table 1 and the thickness of the adhesive layer was changed to the thickness shown in Table 1.

[0414] [Example 20]

[0415] A pressure measurement sheet set was produced in the same manner as in Example 18, except that the resin in the adhesive layer-forming composition was changed to the resin described in Table 1 and the thickness of the adhesive layer was changed to the thickness shown in Table 1.

[0416] [Example 21]

[0417] A pressure measurement sheet set was produced in the same manner as in Example 5, except that the kind of microcapsules containing a color developer in the production of the first sheet was changed to the kind described in Table 1.

[0418] [Example 22]

[0419] A pressure measurement sheet set was produced in the same manner as in Example 21, except that the substrates of the first sheet and the second sheet were changed to the same substrates as in Example 13.

[0420] [Example 23]

[0421] A first sheet was produced in the same manner as in Example 21, except that in the production of the first sheet, 24 parts by mass of carboxymethyl cellulose Na (10% by mass aqueous solution) in the first layer-forming composition was changed to 22 parts by mass of PVA (10% by mass aqueous solution) and 0.5 parts by mass of a crosslinking agent (glyoxal (39% by mass aqueous solution, Tokyo Chemical Industry Co., Ltd.)) and the substrate was changed to the same substrate as in Example 14.

[0422] A second sheet was produced in the same manner as in Example 21, except that in the production of the second sheet, the substrate was changed to the same substrate as in Example 14.

[0423] A pressure measurement sheet set was produced by the above sequence.

[0424] [Example 24]

[0425] A pressure measurement sheet set was produced in the same manner as in Example 23, except that the resin in the adhesive layer-forming composition was changed to the resin described in Table 1 and the thickness of the adhesive layer was changed to the thickness shown in Table 1.

[0426] [Example 25]

[0427] A first layer forming composition was obtained in the same manner as in Example 1, except that the kind of microcapsules containing a color-developing agent was changed to the kind described in Table 1, and 24 parts by mass of a 10% by mass aqueous solution of carboxymethyl cellulose Na was changed to 1.6 parts by mass of a water-soluble monofunctional monomer (FOM-03010, FUJIFILM Wako Pure Chemical Corporation), 0.7 parts by mass of a water-soluble crosslinking agent (FOM-03006, FUJIFILM Wako Pure Chemical Corporation), and 1.5 parts by mass of a water-soluble photoradical initiator (FOM-03011, FUJIFILM Wako Pure Chemical Corporation, 5% aqueous solution).

[0428] The first layer forming composition was applied to the adhesive layer side of the same substrate as in Example 1 using a bar coater and dried, and then irradiated with a high-pressure mercury lamp (manufactured by Ushio Inc.) at 3000 mJ / cm2to form a first layer as a cured film. 2 A first sheet was produced.

[0429] A pressure measurement sheet set was produced using the same second sheet as in Example 1. The thickness of the first layer was 0.5 μm.

[0430] [Examples 26 to 27]

[0431] A pressure measurement sheet set of Examples 26 to 27 was produced in the same manner as in Example 1, except that the structure described in Table 1 was changed.

[0432] [Comparative Example 1]

[0433] [Production of pressure measurement sheet set]

[0434] [Production of substrate of first sheet and second sheet]

[0435] An adhesive layer forming composition having a urethane latex synthesized in Example 1 of Reference Japanese Patent Application No. 2017-171904 was applied to a polyethylene terephthalate sheet (PET) having a thickness of 75 μm and dried to form an adhesive layer having a thickness of 0.1 μm. The obtained substrate (support with adhesive layer) was used for the production of the first sheet and the second sheet of Comparative Example 1 described below.

[0436] [Production of first sheet]

[0437] [First layer forming composition]

[0438] A first layer forming composition was produced in the same manner as in Example 1, except that the kind of microcapsules containing a color developing agent was changed to the kind described in Table 1, and 24 parts by mass of carboxymethyl cellulose Na (10 mass% aqueous solution) in the first layer forming composition was changed to 24 parts by mass of polyolefin (10 mass% aqueous solution).

[0439] A first sheet was produced by coating the first layer forming composition on the adhesive layer of the above-described substrate using a bar coater and drying to form a first layer of about 3 μm.

[0440] <Production of a second sheet>

[0441] A second sheet was produced in the same manner as in Example 1, except that the substrate was changed to the above-described substrate and the coating liquid containing a color developing agent was treated.

[0442] [Comparative Example 2]

[0443] A pressure measuring sheet set was produced in the same manner as in Comparative Example 1, except that in the production of the first sheet, the kind of resin in the first layer forming composition and the thickness of the first layer were changed to the kind of adhesive and the thickness of the first layer described in Table 1.

[0444] [Comparative Example 3]

[0445] (First layer forming composition)

[0446] A first layer forming composition was produced in the same manner as in Example 1, except that the kind of microcapsules containing a color developing agent was changed to the kind described in Table 1.

[0447] A pressure measuring sheet set was produced in the same manner as in Comparative Example 1, except that in the production of the first sheet, the above-described first layer forming composition was used as the first layer forming composition and the thickness of the first layer was changed to the thickness described in Table 1.

[0448] [Confirmation of hydrogen-bonding OH group and hydrogen-bonding NH group and confirmation of crosslinked adhesive]

[0449] [Confirmation of hydrogen-bonding OH group and hydrogen-bonding NH group: Examples 1 to 24, 26 to 27, Comparative Examples 1 to 3]

[0450] The first sheet was immersed in hot water at a temperature of 80 to 95°C for 0.5 to 2 hours to separate the microcapsules from the adhesive. Next, the water of the hot water extract was removed, and infrared absorption spectrum measurement was performed on the powder sample using the KBr method and using an infrared spectrophotometer (FTS7000, manufactured by Digilab).

[0451] Furthermore, regarding the presence or absence of hydrogen-bonded OH and NH groups, it depends on the 3200–3500 cm⁻¹ -1 The presence of a broad absorption peak with a apex was used to determine the result. Furthermore, the obtained infrared absorption spectra were evaluated according to the following criteria.

[0452] <<Evaluation Criteria>>

[0453] "A": 3200-3500cm -1 A broad absorption peak was observed, with a significantly longer peak height compared to the peak heights in the range of 3200–3500 cm⁻¹. -1 The peak heights of other absorption peaks appearing in wavenumber ranges other than the first to third highest (i.e., hydrogen-bonded OH groups and / or hydrogen-bonded NH groups are present in the adhesive, and the content of hydrogen-bonded OH groups and hydrogen-bonded NH groups in the adhesive is higher than the content of other functional groups).

[0454] "B": 3200-3500cm -1 A broad absorption peak was observed, with a peak height significantly higher than that observed in the range of 3200–3500 cm⁻¹. -1 The peak heights of other absorption peaks appearing in wavenumber ranges other than the fourth peak are (i.e., although hydrogen-bonded OH groups and / or hydrogen-bonded NH groups are present in the adhesive, their content is less than that of other functional groups).

[0455] "C": 3200-3500cm -1 There is no broad absorption peak, or even if it exists, its peak height is relatively low compared to peaks outside the 3200–3500 cm⁻¹ range. -1 Other absorption peaks appearing in wavenumber ranges have the smallest peak heights (i.e., hydrogen-bonded OH groups and hydrogen-bonded NH groups are practically non-existent).

[0456] [Confirmation of cross-linked adhesives: Example 25]

[0457] The first sheet from Example 25 was immersed in hot water at a temperature of 80–95°C for 0.5–2 hours, and then thoroughly dried. The weight of the film before and after immersion was then measured. The weight reduction of the film after immersion was less than 5%.

[0458] [Measurement of Shrinkage Rate]

[0459] [Measurement of the shrinkage rate of the first sheet]

[0460] Three samples were prepared, which were cut from the first sheet produced in each embodiment and comparative example, with a length of 150 mm along the length direction of the first sheet and a length of 20 mm along the width direction.

[0461] A mark line was marked on each of position A, which is a position 25 mm from the center point (starting point) of one short side of the sample toward the center point of the other short side and advancing in a direction parallel to the long side, and position B, which is a position 25 mm from the center point (starting point) of one short side of the sample toward the center point of the other short side and advancing in a direction parallel to the long side. At this time, the distance between position A and position B (distance between mark lines) was 100 mm ± 2 mm.

[0462] This was used as a measurement sample for shrinkage S1 in the length direction of the first sheet.

[0463] After the obtained measurement sample was heated at 220°C for 10 minutes, the measurement sample was returned to room temperature (23°C), the distance between mark lines of the measurement sample was measured, and the shrinkage S1a was calculated according to the following formula.

[0464] Shrinkage S1a [%] = 100 x {(distance between mark lines in the measurement sample before heating) - (distance between mark lines in the measurement sample after heating)} / (distance between mark lines in the measurement sample before heating)

[0465] The arithmetic mean of the shrinkages S1a of the three measurement samples was found, and this was set as the shrinkage S1. In addition, the distance between mark lines was measured to the nearest 0.1 mm.

[0466] Also, three samples were prepared in which the first sheet produced in each of the examples and comparative examples was cut so that the length in the direction along the width direction of the first sheet was 150 mm and the length in the direction along the length direction was 20 mm. Also, mark lines were marked on the surface of each sample in the same manner as the measurement sample for shrinkage S1.

[0467] This was used as a measurement sample for shrinkage S2 in the width direction of the first sheet.

[0468] After the obtained measurement sample was heated at 220°C for 10 minutes, the measurement sample was returned to room temperature (23°C), the distance between mark lines of the measurement sample was measured, and the shrinkage S2a was calculated according to the following formula.

[0469] Shrinkage S2a [%] = 100 x {(distance between mark lines in the measurement sample before heating) - (distance between mark lines in the measurement sample after heating)} / (distance between mark lines in the measurement sample before heating)

[0470] The arithmetic mean of the shrinkages S2a of the three measurement samples was found, and this was set as the shrinkage S2. In addition, the distance between mark lines was measured to the nearest 0.1 mm.

[0471] Measurement of shrinkage of the first support and the second support

[0472] The shrinkage S1 and the shrinkage S2 of the first support and the shrinkage S1 and the shrinkage S2 of the second support were calculated in the same manner as the measurement of the shrinkage S1 and the shrinkage S2 in the first sheet, except that the first support used in the production of the first sheet and the second support used in the production of the second sheet were used instead of the first sheet produced in each of the examples and the comparative examples.

[0473] [Various evaluations]

[0474] 〔Deformation〕

[0475] The first sheet and the second sheet produced in each of the examples and the comparative examples were cut into 5 cm x 5 cm each, and the first sheet and the second sheet were overlapped with the first layer surface of the first sheet facing the second layer surface of the second sheet, to obtain a laminate (sheet set).

[0476] Next, a hot press having two heating stages arranged vertically was prepared, and the heating stages were separated from each other, and the laminate was arranged therebetween. Thereafter, the laminate was sandwiched by the two heating stages heated to 220°C, and was pressed at 5.0 MPa for 120 seconds. After the pressing was completed, the pressed laminate was placed on a flat stage, and the deformation thereof was observed, and the evaluation was performed in accordance with the following evaluation criteria. It is preferable to be "B" or more.

[0477] Also, in the following evaluation criteria, as shown in Figure 4 , "floating" means a condition in which the end portion 40E of the laminate 40 floats from the resting surface when resting on the flat stage P.

[0478] <<Evaluation criteria>>

[0479] "A": No floating or unevenness was confirmed on the laminate.

[0480] "B": Slight floating or unevenness was confirmed on the laminate.

[0481] "C": Floating or unevenness was confirmed on the laminate.

[0482] 〔Coating film peeling〕

[0483] The first sheet and the second sheet produced in each of the examples and the comparative examples were cut into 5 cm x 5 cm each, and the first sheet and the second sheet were overlapped with the first layer surface of the first sheet facing the second layer surface of the second sheet, to obtain a laminate (sheet set). Two laminates (sheet sets) were prepared for each of the examples and the comparative examples.

[0484] Next, a hot press having two heating stages arranged vertically was prepared, and the heating stages were separated from each other, and one of the laminates was arranged thereon. Thereafter, the laminate was pressed at 2.5 MPa for 120 seconds using the two heating stages heated to 220°C.

[0485] Next, another laminate was pressed in the same manner except that the pressing condition was changed to 5.0 MPa.

[0486] After the pressing, the two sheets forming the laminate were peeled, and the adhesion / separation of the coating film on the surfaces of the two sheets was visually confirmed, and evaluated according to the following evaluation criteria. "C" or more is preferred.

[0487] <<Evaluation Criteria>>

[0488] "A": The adhesion or separation of the coating film was not confirmed even when the pressing condition was 5.0 MPa.

[0489] "B": The adhesion or separation of the coating film was not confirmed when the pressing condition was 2.5 MPa, but slight adhesion or separation of the coating film was confirmed when the pressing condition was 5.0 MPa.

[0490] "C": The adhesion or separation of the coating film was not confirmed when the pressing condition was 2.5 MPa, but slight adhesion or separation of the coating film was confirmed when the pressing condition was 5.0 MPa.

[0491] "D": The adhesion or separation of the coating film was confirmed even when the pressing condition was 2.5 MPa.

[0492] [Level]

[0493] The first sheet produced in each of the examples and comparative examples and the second sheet cut to a size of 5 cm x 5 cm were overlapped with the first layer surface of the first sheet facing the second layer surface of the second sheet, to obtain a laminate (sheet set). Three laminates (sheet sets) were prepared for each of the examples and comparative examples.

[0494] Next, a hot press having two heating stages arranged vertically was prepared, and the heating stages were separated from each other, and the laminate was arranged thereon. Thereafter, the sheets were colored by pressing at a pressure of 1.0 MPa, 1.5 MPa, and 2.5 MPa using a 200°C hot press. Thereafter, the two overlapped sheets were peeled, and the density (DA) of the colored portion formed on the second sheet was measured using a densitometer RD-19 (manufactured by GRETAG MACBETH).

[0495] And, unlike this, the initial concentration (DB) was measured for the unused second sheet in the same manner. Then, the initial concentration DB was subtracted from the concentration DA to obtain the color development concentration ΔD, and evaluation was performed in accordance with the following evaluation criteria. "B" is preferred.

[0496] <<Evaluation Criteria>>

[0497] "A": ΔD was 0.4 or more when 0.5 MPa, 1.5 MPa, and 2.5 MPa

[0498] "B": ΔD was 0.1 or more and less than 0.4 when any two of 0.5 MPa, 1.5 MPa, and 2.5 MPa

[0499] "C": ΔD was less than 0.1 when any two of 0.5 MPa, 1.5 MPa, and 2.5 MPa

[0500] [Adhesive Tape Peeling]

[0501] The adhesive surface of an adhesive tape (cellophane tape) was attached to the surface of the first layer of the first sheet in a manner of being pressed with a roller. Then, the adhesive tape was peeled from the first sheet, and whether or not the first layer was peeled from the base material (the first support with an adhesive layer) was evaluated. The evaluation criteria were as follows.

[0502] "A": Not peeled.

[0503] "B": Peeling.

[0504] Hereinafter, Table 1 is shown.

[0505] [Table 1]

[0506]

[0507] [Table 2]

[0508]

[0509] From the results of Table 1, it was confirmed that the pressure measurement sheet set of the examples was difficult to cause deformation due to heat even when used at high temperatures, and when the first sheet and the second sheet were peeled after pressurization, peeling occurred at the interface between the first layer and the second layer, and it was difficult to cause coating film breakage. It was further confirmed that the layering of the color development portion formed after heating was also excellent with respect to the pressure measurement sheet set of the examples.

[0510] And, from the comparison of Examples 1 to 4, it was confirmed that when the thickness of the first layer was 0.3 μm or more, coating film breakage was more difficult to occur. And, it was confirmed that when the thickness of the first layer was less than 1 μm (preferably 0.7 μm or less), the layering of the color development portion formed after heating was more excellent.

[0511] And, from the comparison of Examples 5 to 12 and Examples 26 to 27, it was confirmed that when the sheet set for pressure measurement satisfies any of the conditions (A) to (C) shown below, the laminate of the first sheet and the second sheet is less likely to be deformed by heat and the gradation of the color-developed portion formed after heating is more excellent.

[0512] (A) The shrinkage rate S1 of the first sheet in the length direction when heated at 220°C for 10 minutes is 1.0 to 3.0%, and the first support is a sheet in which polyethylene naphthalate is contained at a rate of 70% by mass or more with respect to the total mass of the sheet.

[0513] (B) The first support and the second support are a sheet in which the thickness is 70 μm or more and polyethylene naphthalate is contained at a rate of 70% by mass or more with respect to the total mass of the sheet.

[0514] (C) The first support and the second support are an aromatic polyimide sheet.

[0515] And, from the comparison of Example 15 and Example 16, it was confirmed that when the resin X in the adhesive layer is an acrylic resin, if the thickness of the adhesive layer is 2 μm or more, it is less likely to occur that the coating film is damaged and it is more difficult to occur that the adhesive tape is peeled off.

[0516] Explanation of symbols

[0517] 10 - sheet set for pressure measurement, 12 - first support, 13 - adhesive layer, 14 - first layer, 14A - microcapsule, 14B - adhesive, 16 - first sheet, 18 - second support, 20 - second layer, 22 - second sheet, T1, T2 - thickness of the first layer, P - platform, 40 - laminate, 40E - end portion of the laminate.

Claims

1. A sheet assembly for pressure measurement, comprising: The first sheet, comprising sequentially a first support, an adhesive layer, and a first layer including microcapsules containing a color-developing agent and an adhesive; and The second sheet has a second support and a second layer containing a color developer. The first support and the second support are made of polyethylene naphthalate sheets or aromatic polyimide sheets. The adhesive layer comprises a resin X1 having at least one group selected from aromatic groups, ester bonds, and imide bonds. The capsule wall of the microcapsule contains resin Y1 with aromatic groups. The adhesive in the first layer has an infrared absorption spectrum at 3200 cm⁻¹. -1 ~3500cm -1 Adhesives or cross-linked adhesives that have a peak absorption peak. The thickness of the first layer is 0.2 μm or more.

2. The sheet assembly for pressure measurement according to claim 1, wherein, The adhesive in the first layer has one or more of hydrogen-bonding OH groups and hydrogen-bonding NH groups.

3. The pressure measuring sheet assembly according to claim 1 or 2, wherein, The adhesive in the first layer comprises a resin having one or more of hydroxyl and amide bonds.

4. The pressure measuring sheet assembly according to claim 1 or 2, wherein, The content of resin X1 is 50% by mass or more relative to the total content of resin contained in the adhesive layer.

5. The pressure measuring sheet assembly according to claim 1 or 2, wherein, The resin X1 comprises an acrylic resin, and the thickness of the adhesive layer is 2μm to 10μm.

6. The pressure measuring sheet assembly according to claim 1 or 2, wherein, The resin X1 comprises one or more of acrylic resins and styrene copolymers.

7. The pressure measuring sheet assembly according to claim 1 or 2, wherein, The adhesive in the first layer comprises at least one resin selected from cellulose resins, polyamides, and polyvinyl alcohol.

8. The pressure measuring sheet assembly according to claim 1 or 2, wherein, The resin X1 has aromatic groups. The adhesive layer further comprises resin X2 having one or more of amide bonds and hydroxyl groups. The adhesive in the first layer comprises a resin having one or more of hydroxyl and amide bonds.

9. The pressure measuring sheet assembly according to claim 1 or 2, wherein, The first layer further includes a release agent.

10. The pressure measuring sheet assembly according to claim 1 or 2, wherein it satisfies any of the conditions shown in (A) to (C) below. (A) The first sheet has a length-direction shrinkage rate S1 of 1.0% to 3.0% when heated at 220°C for 10 minutes, and the first support is a sheet containing polyethylene naphthalate at a ratio of 70% by mass or more relative to the total mass of the sheet. (B) The first support and the second support are sheets with a thickness of 70 μm or more and containing polyethylene naphthalate at a ratio of 70% by mass or more relative to the total mass of the sheet. (C) The first support and the second support are aromatic polyimide sheets.

11. The pressure measuring sheet assembly according to claim 1 or 2, wherein, The thermal decomposition temperature of the capsule wall is above 250°C.

12. The pressure measuring sheet assembly according to claim 1 or 2, wherein, The resin Y1 comprises at least one resin selected from polyurethane urea having aromatic groups, polyurea having aromatic groups, and melamine resin.

13. The pressure measuring sheet assembly according to claim 1 or 2, wherein, The resin Y1 has either structure A or structure B as shown below. Structure A: makes Aromatic diisocyanates or alicyclic diisocyanates, Compounds with three or more active hydrogen groups in one molecule and Polymethylene polyphenyl polyisocyanate The structure formed by the reaction, Structure B: A structure formed by reacting melamine with formaldehyde.

14. A method for manufacturing a pressure measuring sheet assembly, as described in any one of claims 1 to 13, comprising: The process of forming the adhesive layer by coating the first support body with the composition having the resin X1; and The process of coating the adhesive layer with one composition selected from composition A and composition B shown below to form the first layer with a thickness of 0.2 μm or more. Composition A: A composition comprising the microcapsules and an ingredient for forming an adhesive having any one or more of hydrogen-bonding OH groups and hydrogen-bonding NH groups. Composition B: A composition comprising the microcapsules and components for forming a crosslinking adhesive.

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