Pressure measuring material and method for producing pressure measuring material

Abstract

A pressure measuring material and a method for manufacturing the pressure measuring material, wherein the pressure measuring material has a substrate and a pressure-sensitive layer, the pressure-sensitive layer comprising: a polymer matrix containing a polymer compound with a molecular weight of 1000 or more; microcapsules containing an electron-donating dye precursor and a solvent; and an electron-accepting compound.

Description

[0001] This application is a divisional application of application number 202080009382.8, entitled "Material for Pressure Measurement and Method for Manufacturing Material for Pressure Measurement". The parent application was filed on January 17, 2020, and the priority date is January 17, 2019. Technical Field

[0002] This invention relates to a material for pressure measurement and a method for manufacturing the material for pressure measurement. Background Technology

[0003] Materials for pressure measurement (i.e., materials used for pressure measurement) are used in applications such as the bonding process of liquid crystal glass, solder printing on printed circuit boards, and pressure adjustment between rollers. Examples of materials used for pressure measurement include pressure measurement films represented by PRESCALE (trade name; registered trademark) supplied by FUJIFILM Corporation.

[0004] Various studies have been conducted on materials used for measuring minute pressures.

[0005] For example, in Japanese Patent Application Publication No. 2009-019949, in order to obtain a concentration that can be visually identified or read under low pressure, a material for pressure measurement is proposed, wherein the color concentration difference ΔD before and after pressurization at 0.05 MPa is 0.02 or more. Summary of the Invention

[0006] The technical problem to be solved by the invention

[0007] As seen in Japanese Patent Application Publication No. 2009-019949, various studies have been conducted on pressure measuring materials for measuring minute pressures. On the other hand, in applications such as compression process management in various manufacturing processes, there is a need for pressure measuring materials for measuring pressures in high-pressure areas (preferably areas of 100 MPa to 10000 MPa).

[0008] However, the upper limit of the measurable pressure range that can be corresponded to by commercially available pressure measurement membranes, that is, the upper limit of the pressure range at which color is obtained by applying pressure, is actually around 300 MPa. Therefore, in the past, pressure measurement materials, especially for pressure measurements exceeding 300 MPa, sometimes could not be fully corresponded.

[0009] Therefore, there is a need for pressure measurement in high-pressure areas. Based on the materials used for pressure measurement in the past, a certain degree of correspondence has been achieved, but in reality, further improvements are desired.

[0010] One objective of this invention is to provide a pressure-measuring material that exhibits excellent color development characteristics in a high-pressure region (preferably a region of 100 MPa to 10000 MPa).

[0011] means for solving technical problems

[0012] The present invention includes the following methods.

[0013] <1> A pressure measuring material having a substrate and a pressure-sensitive layer, the pressure-sensitive layer comprising: a polymer matrix containing a polymer compound with a molecular weight of 1000 or more; microcapsules containing an electron-donating dye precursor and a solvent; and an electron-accepting compound.

[0014] <2> according to <1> The pressure measuring material is in sheet form.

[0015] <3> according to <1> or <2> The pressure measuring material wherein the arithmetic mean roughness Ra of the outermost surface on the side opposite to the substrate is 10.0 μm or less.

[0016] <4> according to <1> to <3> The pressure measuring material according to any one of the above-mentioned methods, wherein the microcapsules and the electron-accepting compound are contained in the polymer matrix.

[0017] <5> according to <4> The pressure measuring material wherein the arithmetic mean roughness Ra of the outermost surface on the side opposite to the substrate is less than 2.0 μm.

[0018] <6> according to <4> or <5> The pressure measuring material, wherein the electron-accepting compound contains a metal salt of salicylic acid.

[0019] <7> according to <4> to <6> The material for pressure measurement described in any one of the above statements has a porosity of 5 mL / m. 2 the following.

[0020] <8> according to <4> to <7> The pressure measuring material according to any one of the above-mentioned methods, wherein the content of the microcapsules is 10% to 80% by volume relative to the pressure-sensitive layer.

[0021] <9> according to <3> The pressure measuring material, wherein the pressure-sensitive layer comprises: a colorimetric layer having the aforementioned electron-accepting compound and the aforementioned polymer matrix; and a color-developing layer having the aforementioned microcapsules.

[0022] The pressure measuring material comprises, in sequence, the substrate, the color developing layer, and the color-emitting layer, wherein the thickness of the color-emitting layer is less than half the thickness of the color developing layer.

[0023] <10> according to <9> The pressure measuring material has an arithmetic mean roughness Ra of 2.0 μm to 10.0 μm on the outermost surface opposite to the substrate.

[0024] <11> according to <9> or <10> The pressure measuring material, wherein the electron-accepting compound contains acidic clay or activated clay.

[0025] <12> according to <11> The pressure measuring material, wherein the pressure-sensitive layer has inorganic particles other than the electron-accepting compound.

[0026] <13> according to <9> to <12> The material for pressure measurement described in any one of the above statements has a porosity of 5 mL / m. 2 ~20mL / m 2 .

[0027] <14> according to <1> to <13> The pressure measuring material according to any one of the following methods, wherein the ratio T / p of the thickness T of the layer after subtracting the thickness of the substrate from the thickness of the pressure measuring material to the inner diameter p of the microcapsule is 1.2 or more.

[0028] <15> according to <14> The pressure measuring material, wherein the ratio T of the layer thickness (after subtracting the thickness of the substrate from the thickness of the pressure measuring material) to the inner diameter p of the microcapsule is 1.2 to 5.0.

[0029] <16> according to <1> to <15> The pressure measuring material according to any one of the above-mentioned methods, wherein, relative to the total mass of the pressure-sensitive layer, contains 10% by mass or more of the above-mentioned polymeric compound with a molecular weight of 1000 or more.

[0030] <17> according to <1> to <16> The pressure measuring material according to any one of the following methods, wherein the substrate is a polyethylene terephthalate substrate or a polyethylene naphthalate substrate.

[0031] <18> according to <1> to <17> The pressure measuring material according to any one of the above-mentioned methods, wherein an easy-to-adhere layer is provided between the substrate and the pressure-sensitive layer.

[0032] <19> according to <1> to <18> The pressure measuring material according to any one of the following methods, wherein the wall material of the microcapsules contains at least one selected from polyurethane urea and polyurethane.

[0033] <20> A method for manufacturing a material for pressure measurement, wherein... <4> to <8> and <14> to <19> The method for manufacturing the pressure measuring material described in any one of the following methods includes: a step of disposing a pressure-sensitive layer forming composition on a substrate.

[0034] The pressure-sensitive layer forming composition comprises: a polymer matrix containing a polymer compound with a molecular weight of 1000 or more; microcapsules containing an electron-donating dye precursor and a solvent; and an electron-accepting compound.

[0035] <21> A method for manufacturing a material for pressure measurement, wherein... <9> to <19> The method for manufacturing the pressure measuring material described in any one of the following methods comprises:

[0036] A process for obtaining a color-forming composition, the color-forming composition comprising microcapsules and a solvent, wherein the microcapsules contain an electron-donating dye precursor and a solvent;

[0037] A process for obtaining a colorimetric layer forming composition, wherein the colorimetric layer forming composition contains an electron-accepting compound and a polymeric compound with a molecular weight of 1000 or more;

[0038] The process of depositing the above-described color-developing layer forming composition on a substrate to form a color-developing layer; and

[0039] The process of forming a color-developing layer by depositing the color-developing layer onto the color-developing layer and forming the color-developing layer.

[0040] Invention Effects

[0041] According to one embodiment of the present invention, a pressure testing material that can achieve excellent color development with superior gradation in a high-pressure region (preferably a region of 100 MPa to 10000 MPa) can be provided. Attached Figure Description

[0042] Figure 1 It is a graph showing the relationship between pressure and color concentration in the evaluation of color development characteristics in the embodiments.

[0043] Figure 2 This is a schematic cross-sectional view illustrating an example of the material for pressure measurement according to the present invention.

[0044] Figure 3 This is a schematic cross-sectional view illustrating an example of the material for pressure measurement according to the present invention. Detailed Implementation

[0045] The pressure measuring material of the present invention, including its manufacturing method, will be described in detail below. The pressure measuring material and its manufacturing method of the present invention are not limited to the following embodiments, and can be appropriately modified and implemented within the scope of the objectives of the present invention.

[0046] In this invention, the numerical range represented by “~” refers to the range encompassed by the numerical values ​​recorded before and after “~” as the lower and upper limits.

[0047] In the numerical ranges described in stages in this invention, the upper or lower limit value recorded in a certain numerical range can be replaced with the upper or lower limit value of other numerical ranges described in stages. Furthermore, in the numerical ranges described in this invention, the upper or lower limit value recorded in a certain numerical range can also be replaced with the value shown in the embodiments.

[0048] In this invention, when a composition contains multiple substances corresponding to each component, unless otherwise specified, the amount of each component in the composition refers to the total amount of the multiple substances present in the composition.

[0049] In this invention, a combination of two or more preferred methods is a more preferred method.

[0050] In this invention, the electron-donating dye precursor is also referred to as a "color-developing agent", and the electron-accepting compound that makes the electron-donating dye precursor color-develop is also referred to as a "color-developing agent".

[0051] <Materials for Pressure Measurement and Their Manufacturing Methods>

[0052] The pressure measuring material of the present invention has a substrate and a pressure-sensitive layer. The pressure-sensitive layer contains: a polymer matrix (hereinafter also simply referred to as "polymer matrix") containing a polymer compound with a molecular weight of 1000 or more; microcapsules containing an electron-donating dye precursor and a solvent; and an electron-accepting compound. In addition to the substrate and the pressure-sensitive layer, the pressure measuring material of the present invention may also have other layers (e.g., a white layer, a protective layer, an easy-to-adhere layer, etc.) as needed.

[0053] Materials for pressure measurement have been proposed and widely used for a long time. However, conventional materials for pressure measurement have focused on obtaining concentrations that can be visually identified or read even when a small pressure is applied. For example, the material for pressure measurement described in Japanese Patent Application Publication No. 2009-019949 focuses on measurements under very small pressures of less than 0.1 MPa.

[0054] However, even with a mechanism that is effective for obtaining a wide concentration range (e.g., control of microcapsule particle size, wall thickness, constituent materials, etc.), it is sometimes difficult to design a mechanism that can exhibit a wide concentration range when measuring pressure in a high-pressure region, when measuring pressure at very low pressure.

[0055] In view of the above, the pressure measuring material of the present invention has a substrate and a pressure-sensitive layer, wherein the pressure-sensitive layer is configured as a layer containing a polymer matrix, microcapsules containing an electron-donating dye precursor and a solvent, and an electron-accepting compound.

[0056] Therefore, the pressure measuring material of the present invention can obtain excellent color development in high pressure regions (preferably in the region of 100MPa to 10000MPa, more preferably in the region of 300MPa to 3000MPa).

[0057] The reason why the pressure measuring material of the present invention achieves the above-mentioned effects is not yet certain, but the inventors speculate as follows: the pressure-sensitive layer contains a polymer matrix, microcapsules containing an electron-donating dye precursor and a solvent, and an electron-accepting compound, thereby mitigating the pressure applied to the microcapsules even under high pressure, enabling pressure measurements with excellent color gradation. However, this speculation does not limit the explanation of the effects of the pressure measuring material of the present invention.

[0058] In this invention, "color development hierarchy" refers to the property that the color concentration increases with the increase of pressure applied to the material used for pressure measurement.

[0059] In the pressure-measuring material of the present invention, color development occurs in the pressure-sensitive layer through contact between an electron-donating dye precursor contained within microcapsules and an electron-accepting compound serving as a color developer. This color development indicates a concentration corresponding to the intensity of the external force applied to the pressure-measuring material (pressure applied from the outside, hereinafter the same), i.e., the level of color development. For example, when surface pressure is applied to the pressure-measuring material, if the applied surface pressure is not uniform across the entire surface, the color development is at a concentration corresponding to the pressure, thus obtaining an image with concentration levels.

[0060] Furthermore, the pressure measurement material of the present invention can be a material that can obtain color gradation in the range of 100 MPa to 10000 MPa, and can obtain color gradation even when pressures of less than 100 MPa and / or more than 10000 MPa are applied.

[0061] [Substrate]

[0062] The pressure measuring material of the present invention has a substrate.

[0063] The substrate can be any shape, such as sheet or plate. The preferred shape is sheet-like. That is, the pressure measuring material of the present invention is preferably a sheet-like pressure measuring material having a sheet-like substrate and a pressure-sensitive layer. In the present invention, "sheet-like" refers to having two main planes, a thickness of 1 mm or less (preferably 1 μm to 1 mm), and flexibility. In the present invention, "sheet-like" includes "film-like," and both are used synonymously. "Plate-like" refers to having two main planes and a thickness exceeding 1 mm (preferably exceeding 1 mm and less than 10 mm).

[0064] The substrate is not particularly limited; specific examples include paper, synthetic paper, plastic substrates, metal substrates, and composite substrates. From the viewpoint of ease of handling, a plastic substrate is preferred.

[0065] Specific examples of paper include high-quality paper, medium-quality paper, straw paper, neutral paper, acidic paper, recycled paper, coated paper, machine-coated paper, art paper, cast-coated paper, micro-coated paper, tracing paper, etc.

[0066] Specific examples of plastics that form plastic substrates include polyesters such as polyethylene terephthalate (PET) and polyethylene naphthalate (PEN), cellulose derivatives such as cellulose triacetate, polyolefins such as polypropylene and polyethylene, and polystyrene.

[0067] Specific examples of synthetic paper include synthetic paper (such as YUPO) formed by biaxial stretching of polypropylene or polyethylene terephthalate, synthetic paper made using synthetic fibers such as polyethylene fiber, polypropylene fiber, polyethylene terephthalate fiber, and polyamide fiber, laminates formed by stacking them on a part of another synthetic paper, and laminates formed on one or both sides.

[0068] The substrate is preferably a substrate containing metal. Examples of substrates for this method include metal substrates and composite substrates of metal and plastic.

[0069] There are no particular restrictions on the metal used, but from the viewpoint that it is not easily deformed relative to the measuring pressure, metals such as stainless steel (SUS) are preferred.

[0070] As a plastic substrate, it can be formed into a substrate with high hardness and flatness, and can better balance the measurement and color concentration in the high pressure area. Therefore, polyethylene terephthalate substrate or polyethylene naphthalate substrate is preferred.

[0071] From the viewpoint of reproducibility of the colorimetric concentration corresponding to pressure, a substrate that exhibits less deformation due to pressure application, is unaffected by the object being measured, and can suppress pressure dispersion that could reduce measurement accuracy is preferred. Polyethylene naphthalate substrates or metal-containing substrates are preferred examples of such substrates.

[0072] Since it can improve the contrast between the colored and uncolored areas, thereby further enhancing visual recognizability, the hue of the substrate is preferably white. As a white substrate, a plastic substrate is preferred, and a white polyethylene terephthalate substrate is more preferably used. As a white polyethylene terephthalate substrate, any substrate containing a known white pigment (e.g., white dye) in the polyethylene terephthalate substrate is suitable.

[0073] There is no particular limitation on the thickness of the substrate, but for the reasons of ease of handling and the ability to supply in roll form, it is preferred to be 10 μm to 500 μm, and more preferably 10 μm to 200 μm.

[0074] [Pressure-sensitive layer]

[0075] The pressure measuring material of the present invention has a pressure-sensitive layer on a substrate.

[0076] The pressure-sensitive layer is a layer containing a polymer matrix, microcapsules containing electron-donating dye precursors and solvents, and electron-accepting compounds.

[0077] (polymer matrix)

[0078] In this invention, the term polymer matrix is ​​a constituent element of the pressure-sensitive layer and is used to refer to a matrix formed containing a polymer compound with a molecular weight of 1000 or more (hereinafter also referred to as a specific polymer compound).

[0079] Certain polymeric compounds preferably function as adhesives in the pressure-sensitive layer. Compounds constituting the microcapsules (including the microcapsule contents, wall material, and dispersant used in microcapsule formation) and electron-accepting compounds are not included in the specific polymeric compounds.

[0080] By including specific polymer compounds in the pressure-sensitive layer, it can be confirmed that the polymer matrix is ​​a constituent element of the pressure-sensitive layer involved in the pressure measuring material of the present invention.

[0081] From the viewpoint of further improving the layering of the high-pressure region, it is preferable to contain 10% by mass or more of a specific polymeric compound relative to the total mass of the pressure-sensitive layer, and more preferably 20% by mass or more. When the amount of the specific polymeric compound is 10% by mass or more, the external force (pressure) applied to the pressure measuring material can be gently applied, making it easier to retain components such as microcapsules and electron-accepting compounds in the pressure-sensitive layer.

[0082] From the viewpoint of color concentration, the content of the specific polymer compound forming the polymer matrix is ​​preferably 10% to 70% by mass, more preferably 20% to 50% by mass, relative to the total mass of the pressure-sensitive layer.

[0083] There are no particular restrictions on the specific polymer compound used; it can be appropriately selected based on the desired properties of the pressure-sensitive layer that are not easily deformed relative to the measured pressure.

[0084] A specific polymer compound can be used alone or in combination with two or more compounds.

[0085] Examples of specific polymeric compounds include polyvinyl alcohol, polyurethane-based polymers containing polyurethane, vinyl chloride-based polymers, vinyl acetate-based polymers, acrylic polymers, styrene-butadiene rubber (SBR), or copolymers thereof.

[0086] Here, polyurethane polymers, vinyl chloride polymers, vinyl acetate polymers, and acrylic polymers refer to polymers containing structural units with polyurethane bonds, structural units derived from vinyl chloride, structural units derived from vinyl acetate, and structural units derived from (meth)acrylic acid, respectively.

[0087] Certain polymeric compounds can also be contained in the pressure-sensitive layer in the form of a dispersion.

[0088] From the perspective of applicability in microcapsule preparation and productivity in aqueous coating, polyvinyl alcohol is one of the suitable methods for certain polymer compounds.

[0089] There are no particular limitations on polyvinyl alcohol; it can be appropriately selected based on the desired properties of the pressure-sensitive layer.

[0090] From the viewpoint of further enhancing the hierarchical nature of the high-pressure region while maintaining microcapsules, the degree of polymerization of polyvinyl alcohol is preferably 100 to 10,000, more preferably 100 to 3,000.

[0091] From the viewpoint of further enhancing the hierarchical nature of the high-pressure region, such as maintaining microcapsules, the molecular weight of the specific polymer compound is 1000 or more, preferably 2000 or more, more preferably 5000 or more, and even more preferably 10000 or more. There is no particular upper limit to the molecular weight; for example, 1000,000 can be cited. From the viewpoint of ease of manufacture, the molecular weight is preferably 2000 to 100,000, more preferably 5000 to 100,000, and even more preferably 10,000 to 100,000. Here, the molecular weight of the specific polymer compound represents the number-average molecular weight determined by gel permeation chromatography (GPC).

[0092] Specifically, the molecular weights mentioned above were determined using a gel permeation chromatography (GPC) analysis apparatus employing columns of TSKgel GMHxL, TSKgel G4000HxL, and TSKgel G2000HxL (all trade names manufactured by Tosoh Corporation), with THF (tetrahydrofuran) as the solvent and a differential refractometer as the standard substance, and were converted using polystyrene.

[0093] As a specific polymer compound, it can also be used in commercially available products. Commercially available products include: PVA-105 (polyvinyl alcohol) and PVA-205 (polyvinyl alcohol) manufactured by KURARAY CO., LTD.; SUPERFLEX 170 (polyurethane polymer), SUPERFLEX 820 (polyurethane polymer), SUPERFLEX 830HS (polyurethane polymer), and SUPERFLEX 870 (polyurethane polymer) manufactured by DKS Co., Ltd.; ViniBran 287 (vinyl chloride-acrylic polymer), ViniBran 900 (vinyl chloride-acrylic polymer), ViniBran 2684 (acrylic polymer), ViniBran 2685 (acrylic polymer), ViniBran 2687 (acrylic polymer), and ViniBran 715S (vinyl chloride polymer) manufactured by Nissin Chemical Industry CO., Ltd.; and Sumikaflex 752HQ (ethylene-vinyl acetate copolymer resin emulsion) and Sumikaflex manufactured by Sumika Chemtex Company. 808HQ (ethylene-vinyl acetate-vinyl chloride copolymer emulsion), Sumikaflex 850HQ (ethylene-vinyl acetate-vinyl chloride copolymer emulsion), Sumikaflex 830 (ethylene-vinyl acetate-vinyl chloride copolymer emulsion); Nipol LX433C (styrene-butadiene rubber), Nipol LX2507H (styrene-butadiene rubber), Nipol LX416 (styrene-butadiene rubber), Nipol LX814 (acrylic polymer), Nipol LX855EX1 (acrylic polymer) manufactured by Zeon Corporation; Movinyl 742A (acrylic polymer), Movinyl 1711 (acrylic polymer), Movinyl 6520 (acrylic polymer), Movinyl 7980 (acrylic polymer), Movinyl 081F (vinyl acetate-ethylene copolymer), Movinyl 082 (vinyl acetate-ethylene copolymer); Smarttex SN-307R (styrene-butadiene latex) manufactured by Nippon A&L Inc., etc.

[0094] Marlowe hardness is one of the preferred physical properties of specific polymer compounds that form a polymer matrix.

[0095] From the viewpoint of considering both pressure measurement and color concentration in high-pressure regions (preferably 100MPa to 10000MPa, more preferably 300MPa to 3000MPa), the polymer matrix involved in this invention preferably contains a Marlowen hardness of 100 N / mm. 2 The above are high molecular weight compounds.

[0096] The polymer matrix contains a Marldor hardness of 100 N / mm. 2 The above-mentioned polymer compounds, even when pressure is measured in the high-pressure region of the pressure-sensitive layer, suppress the deformation of the pressure-sensitive layer and can obtain high-precision color gradation, therefore they are preferred.

[0097] The preferred Martens hardness for polymer compounds is 140 N / mm. 2 above.

[0098] There is no particular limitation on the upper limit of the Martens hardness of polymer compounds; it can be set to 300 N / mm. 2 the following.

[0099] Martens hardness can be determined using the nanoindentation method according to ISO 14577-1 (Instrumented Indentation Hardness), as a value obtained by dividing the maximum test load by the surface area of ​​the indenter at the maximum indentation depth. Measurement can be performed, for example, using a microhardness tester such as the FISCHER INSTRUMENTS KK "HM2000".

[0100] The specific measurement methods are shown in the examples described below.

[0101] (Microcapsules)

[0102] The pressure-sensitive layer contains microcapsules containing electron-donating dye precursors and solvents.

[0103] Microcapsules typically have a core and a capsule wall for containing the core material (also called inclusions or contents) that makes up the core.

[0104] The microcapsule contains an electron-donating dye precursor and a solvent as a core material (inner component). Because the electron-donating dye precursor is contained within the microcapsule, it can remain stable until the microcapsule is destroyed by pressure.

[0105] -Wall material of microcapsules-

[0106] As the wall material for microcapsules, water-insoluble or oil-insoluble polymers that have been conventionally used as wall materials for microcapsules containing electron-donating dye precursors in pressure-sensitive recording materials can be used without particular limitation. Among these, polyurethane urea, polyurethane, polyurea, melamine-formaldehyde resin, and gelatin are preferred as wall materials. From the viewpoint of obtaining good color development, polyurethane urea, polyurethane, polyurea, and melamine-formaldehyde resin are more preferred, and polyurethane urea and polyurethane containing polyurethane bonds are particularly preferred.

[0107] The capsule wall of the microcapsule is preferably substantially composed of resin. "Substantially composed of resin" means that the resin content is 90% by mass or more, preferably 100% by mass, relative to the total mass of the capsule wall. That is, the capsule wall of the microcapsule is preferably composed of resin.

[0108] In addition, polyurethane is a polymer having multiple polyurethane bonds, and is preferably a reaction product formed from raw materials containing polyols and polyisocyanates.

[0109] Furthermore, polyurea is a polymer with multiple urea bonds, and is preferably a reaction product formed from raw materials containing polyamines and polyisocyanates. Alternatively, polyurea can be synthesized using polyisocyanates without the use of polyamines, by reacting a portion of the polyisocyanate with water to form a polyamine.

[0110] Furthermore, polyurethane urea is a polymer containing polyurethane bonds and urea bonds, and is preferably a reaction product formed from raw materials containing polyols, polyamines, and polyisocyanates. Additionally, when polyols react with polyisocyanates, a portion of the polyisocyanate reacts with water to form a polyamine, sometimes resulting in the acquisition of polyurethane urea.

[0111] Furthermore, the melamine-formaldehyde resin is preferably a reaction product formed by the condensation polymerization of melamine and formaldehyde.

[0112] Furthermore, the aforementioned polyisocyanates are compounds having two or more isocyanate groups, and examples include aromatic polyisocyanates and aliphatic polyisocyanates. As a polyisocyanate, for example, it can be an adduct (addition) of a polyol such as trimethylolpropane and a difunctional polyisocyanate.

[0113] Furthermore, the aforementioned polyols are compounds having two or more hydroxyl groups, such as low molecular weight polyols (e.g., aliphatic polyols, aromatic polyols; furthermore, "low molecular weight polyols" refers to polyols with a molecular weight of 400 or less), polyvinyl alcohol, polyether polyols, polyester polyols, polylactone polyols, castor oil polyols, polyolefin polyols, and hydroxyl-containing amine compounds (e.g., amino alcohols; examples of amino alcohols include N,N,N',N'-tetra(2-hydroxypropyl)ethylenediamine, an amino compound such as ethylenediamine, which is an adduct of propylene oxide or ethylene oxide).

[0114] Furthermore, the aforementioned polyamines are compounds having two or more amino groups (primary or secondary amino groups), such as aliphatic polyamines like diethylenetriamine, triethylenetetramine, 1,3-propenyldiamine, and hexamethylenediamine; epoxy adducts of aliphatic polyamines; alicyclic polyamines like piperazine; and heterocyclic diamines like 3,9-bis-aminopropyl-2,4,8,10-tetraoxaspiro-(5,5)undecane.

[0115] The number-average wall thickness δ of the microcapsules depends on various conditions such as the type of capsule wall material and the capsule diameter. However, from the viewpoint of color development in high-pressure regions (preferably 100MPa to 10000MPa, more preferably 300MPa to 3000MPa), it is preferably 0.02μm to 3μm, more preferably 0.05μm to 2μm.

[0116] The wall thickness of a microcapsule refers to the thickness (μm) of the resin film (the so-called capsule wall) of the microcapsule particles. Number-average wall thickness refers to the average value obtained by averaging the wall thickness (μm) of five individual microcapsules obtained using scanning electron microscopy (SEM). Specifically, the microcapsule liquid is first coated onto any support and dried to form a coated film. A cross-sectional section of the obtained coated film is prepared, and the section is observed using SEM. Five microcapsules are selected, and the cross-section of each selected microcapsule is observed to determine the capsule wall thickness, and the average value is calculated. The cross-sectional section can also be made from materials used for pressure measurement.

[0117] -Electron-donating dye precursor-

[0118] As an electron-donating dye precursor, it only needs to have the ability to donate electrons or accept protons (hydrogen ions; H+) from acids. + The nature of the color development is not particularly limited, but colorless is preferred. Electron-donating dye precursors can function as color-developing agents.

[0119] In particular, as an electron-donating dye precursor, it is preferred to be a colorless compound having a partial skeleton such as lactone, lactam, sulopentalide, spiropyran, ester, or amide, which, upon contact with an electron-accepting compound described later, undergoes ring-opening or cleavage.

[0120] Electron-donating dye precursors are substances known to be used in applications such as pressure-sensitive carbon paper or thermal recording paper. Examples of electron-donating dye precursors include triphenylmethane phthalide compounds, fluorane compounds, phenanthrene compounds, indole phthalide compounds, colorless golden ammonia compounds, rhodamine lactam compounds, triphenylmethane compounds, diphenylmethane compounds, triazine compounds, spiropyran compounds, fluorene compounds, and many other compounds.

[0121] For details regarding the above-mentioned compounds, please refer to Japanese Patent Application Publication No. 5-257272 and International Publication No. 2009 / 8248, paragraphs

[0029] to

[0034] .

[0122] Electron-donating dye precursors can be used alone or in combination with two or more.

[0123] In one aspect of the invention, from a visual recognizability point of view, the electron-donating dye precursor is preferably a substance with a high molar absorptivity (ε). The molar absorptivity (ε) of the electron-donating dye precursor is preferably 10000 mol / L. -1 ·cm -1 ·L or more, more preferably 15000mol -1 ·cm -1 •L or higher, more preferably 25000 mol -1 ·cm -1 ·L and above.

[0124] The molar absorptivity (ε) can be calculated based on the absorbance when an electron-donating colorless dye is dissolved in a 95% (w / w) aqueous solution of acetic acid. Specifically, in a 95% (w / w) aqueous solution of an electron-donating colorless dye with an absorbance adjusted to 1.0 or less, and with the length of the measuring unit set to A cm, the concentration of the electron-donating colorless dye set to B mol / L, and the absorbance set to C, it can be calculated using the following formula.

[0125] Molar absorptivity (ε) = C / (A×B)

[0126] From the viewpoint of improving the color development properties, preferably within a pressure range of 100 MPa to 10000 MPa (more preferably 300 MPa to 3000 MPa), the content (e.g., coating amount) of the electron-donating dye precursor in the pressure-sensitive layer, based on the mass after drying, is preferably 0.1 g / m³. 2 ~5g / m 2 More preferably 0.1 g / m 2 ~4g / m 2 Further preferred is 0.2 g / m 2 ~3g / m 2 .

[0127] -solvent-

[0128] The microcapsules contain at least one solvent. The solvent functions as an oil component that dissolves electron-donating dye precursors.

[0129] As a solvent, it can be used with solvents known for their application in pressure-sensitive carbon paper.

[0130] From the viewpoint of stably dissolving without precipitating electron-donating dye precursors, the solvent preferably contains 50% to 100% by mass of a solvent with a boiling point exceeding 130°C, more preferably 70% to 100% by mass, and even more preferably 90% to 100% by mass. Furthermore, there is no particular limitation on the upper limit of the boiling point; for example, 500°C can be cited, but it is preferred to exceed 130°C and be below 500°C.

[0131] Examples of solvents include alkylnaphthalene compounds such as diisopropylnaphthalene; diarylalkane compounds such as 1-phenyl-1-dimethylethane; alkylbiphenyl compounds such as isopropyl biphenyl; triarylmethane compounds; alkylbenzene compounds; benzylnaphthalene compounds; diarylalkylene compounds; aromatic hydrocarbons such as arylindenium compounds; ester compounds such as dibutyl phthalate; aliphatic hydrocarbons such as isoparaffins; natural vegetable and animal oils such as soybean oil, corn oil, cottonseed oil, rapeseed oil, olive oil, coconut oil, castor oil, and fish oil; and high-boiling fractions of natural substances such as mineral oil.

[0132] Solvents can be used alone or in combination of two or more.

[0133] From the viewpoint of color development, the mass ratio (solvent:precursor) of the solvent contained in the microcapsule to the electron-donating dye precursor is preferably in the range of 98:2 to 30:70, more preferably in the range of 97:3 to 40:60, and even more preferably in the range of 95:5 to 50:50.

[0134] -Other ingredients-

[0135] In addition to the aforementioned electron-donating dye precursors, solvents, and auxiliary solvents, microcapsules may also contain additives as needed. Examples of additives include ultraviolet absorbers, light stabilizers, antioxidants, paraffin wax, and odor suppressants. Furthermore, solvents with boiling points below 130°C used in the manufacture of microcapsules may also be included (e.g., ketone compounds such as methyl ethyl ketone, ester compounds such as ethyl acetate, and alcohol compounds such as isopropanol).

[0136] The content of the pressure-sensitive layer in the microcapsule (coating amount during coating) relative to the total solid content of the pressure-sensitive layer is preferably 10% to 80% by mass, more preferably 10% to 60% by mass, and even more preferably 10% to 50% by mass.

[0137] -Methods for making microcapsules-

[0138] Microcapsules can be manufactured using any method known to them, such as interfacial polymerization, internal polymerization, phase separation, external polymerization, and agglomeration.

[0139] Examples of microcapsules using polyurethane urea, polyurethane, and polyurea as capsule wall materials can be found in paragraphs

[0040] to

[0044] of Japanese Patent Application Publication No. 2009-019949. Specifically, a method for forming microcapsules involves mixing a compound used to form the wall material of the microcapsule with a core material of the microcapsule, and then reacting the compound used to form the wall material. When forming microcapsules, a dispersant such as polyvinyl alcohol is preferably used.

[0140] (Electron-accepting compounds)

[0141] The pressure-sensitive layer contains at least one electron-accepting compound. This electron-accepting compound can function as a colorimetric agent.

[0142] Both inorganic and organic compounds can be cited as examples of electron-accepting compounds.

[0143] Specific examples of inorganic compounds include clays such as acidic clay, activated clay, magnesia, zeolite, bentonite, and kaolin.

[0144] Specific examples of organic compounds include metal salts of aromatic carboxylic acids (preferably metal salts of salicylic acid), phenol-formaldehyde resins, and metal salts of carboxylated terpene phenol-formaldehyde resins.

[0145] Among them, the preferred electron-accepting compound is an acidic clay, activated clay, zeolite, kaolin, a metal salt of an aromatic carboxylic acid, or a metal salt of a carboxylated terpene phenolic resin, and more preferably an acidic clay, activated clay, kaolin, or a metal salt of an aromatic carboxylic acid.

[0146] Preferred examples of aromatic carboxylic acids in metal salts include 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, and 3,5-bis(α,α-dimethylbenzyl) 3-(α,α-dimethylbenzyl)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, and 3-phenyl-5-(α,α-dimethylbenzyl)salicylic acid. Furthermore, carboxyl-modified terpene phenolic resins and salicylic acid resins, which are the reaction products of 3,5-bis(α-methylbenzyl)salicylic acid and benzyl chloride, can also be used as aromatic carboxylic acids. Specific examples of metal salts among the metal salts of aromatic carboxylic acids include zinc salts, nickel salts, aluminum salts, and calcium salts.

[0147] The content of the electron-accepting compound in the pressure-sensitive layer (coating amount during coating) is preferably 0.1 g / m² based on dry weight. 2 ~30g / m 2 When the electron-accepting compound is an inorganic compound, the preferred content is 3 g / m³ based on dry mass. 2 ~20g / m 2 Further preferred is 5g / m 2 ~15g / m 2 The preferred content of the electron-accepting compound, when it is an organic compound, is 0.1 g / m³ on a dry weight basis. 2 ~15g / m 2 Further preferred is 0.2 g / m 2 ~10g / m 2 .

[0148] (Oil-absorbing particles)

[0149] The pressure-sensitive layer preferably contains at least one oil-absorbing particle on the outside of the microcapsule.

[0150] Because high pressure is applied to the pressure measuring material of the present invention, there is a tendency for the solvent (oil component) contained in the microcapsules to easily leach out to the outside of the pressure-sensitive layer. This leaching of the oil component causes oil stains, which is therefore undesirable. In contrast, by containing oil-absorbing particles on the outside of the microcapsules within the pressure-sensitive layer, the leaching of the oil component to the outside of the pressure-sensitive layer can be effectively suppressed.

[0151] In this invention, "oil-absorbing particles" refers to particles that exhibit an oil absorption capacity of 50% or more of their own weight in flaxseed oil at 25°C.

[0152] The method for determining oil absorption was in accordance with JIS-K5101-13-1:2004.

[0153] As for the shape of a particle, examples include spheres, ellipses, rods, etc., or other shapes.

[0154] The particle size of the oil-absorbing particles is preferably 0.5 μm to 20 μm, more preferably 1 μm to 10 μm, and even more preferably 2 μm to 8 μm.

[0155] The particle size of the oil-absorbing particles can be determined using a Microtrac MT3300EXII (manufactured by Nikkiso Co., Ltd.).

[0156] Examples of oil-absorbing particles include inorganic particles such as porous silica particles, calcium carbonate, kaolin, aluminum silicate, calcium silicate, colloidal silica, alumina, and aluminum hydroxide, as well as polymer particles such as polyolefins, acrylic acid, polystyrene, and polyester. Preferably, at least one inorganic particle selected from porous silica particles, calcium carbonate, and kaolin is used.

[0157] As an oil-absorbing particle, it can also be an oil-absorbing compound among electron-accepting compounds used as color developers.

[0158] As oil-absorbing particles, commercially available products can be used, such as the "Brilliant series" manufactured by Shiraishi Group ALL RIGHTSRESERVED.

[0159] The content of oil-absorbing particles in the pressure-sensitive layer can be appropriately set according to the desired oil absorption.

[0160] (Inorganic particles)

[0161] The pressure-sensitive layer preferably contains at least one inorganic particle that is not an electron-accepting compound on the outside of the microcapsule.

[0162] Examples of inorganic particles include porous silica particles, calcium carbonate, kaolin, aluminum silicate, calcium silicate, colloidal silica, alumina, and aluminum hydroxide, with silica being preferred. The inorganic particles can be any of the aforementioned oil-absorbing particles.

[0163] As inorganic particles, commercially available products can be used, such as the "Mizukasil series" manufactured by MIZUSAWA INDUSTRIAL CHEMICALS, LTD.

[0164] The preferred particle size for inorganic particles is 1 μm to 30 μm, and more preferably 5 μm to 20 μm.

[0165] (Other ingredients)

[0166] Other components that may be included in the pressure-sensitive layer include surfactants, optical brighteners, defoamers, penetrants, ultraviolet absorbers, and preservatives.

[0167] (Thickness t of the pressure-sensitive layer)

[0168] There are no particular limitations on the thickness t of the pressure-sensitive layer, and it can be selected according to the purpose, etc.

[0169] The thickness t of the pressure-sensitive layer is preferably 1μm to 250μm, more preferably 3μm to 200μm, even more preferably 5μm to 150μm, and especially preferably 5μm to 50μm.

[0170] In addition, as described in the second method below, when the pressure-sensitive layer has a color-emitting layer and a color-developing layer, the total thickness of the color-emitting layer and the color-developing layer is the thickness of the pressure-sensitive layer.

[0171] The thickness t of the pressure-sensitive layer can be measured by microscopic observation.

[0172] Specifically, it is possible to cut the pressure-measuring material vertically to create a cross-sectional slice, observe the cross-sectional slice using a scanning electron microscope (SEM), and determine the thickness of the pressure-sensitive layer based on the image. An example of a scanning electron microscope is the tabletop microscope "Miniscope TM3030Plus" (manufactured by Hitachi High-Technologies Corporation).

[0173] In addition, the thickness of the pressure-sensitive layer in this invention is the arithmetic mean of the thicknesses at 10 randomly selected locations.

[0174] The coefficient of variation (CV value; also referred to as CV value) for the particle size distribution of all particles contained in the pressure-sensitive layer is preferably 20% to 150%.

[0175] When the CV value is within the above range, the particle distribution in the pressure-sensitive layer, especially the relative deviation of the microcapsules, is small, resulting in excellent color development.

[0176] The CV value is preferably 20% to 110%, more preferably 25% to 80%.

[0177] In addition, the CV value represents the relative deviation of the particles contained in the pressure-sensitive layer, and is calculated as follows.

[0178] CV value (%) = Standard deviation / Arithmetic mean particle size × 100

[0179] The arithmetic mean particle size and standard deviation were calculated by taking an optical microscope at 150x magnification of the surface of the pressure-sensitive layer and measuring the size of all microcapsules within a randomly set 2cm × 2cm area.

[0180] (Layer structure of the pressure-sensitive layer)

[0181] The pressure-sensitive layer of the present invention can be a single-layer structure or a multi-layer structure.

[0182] One possible configuration for a pressure-sensitive layer is to contain microcapsules and electron-accepting compounds within a polymer matrix. The first configuration of a pressure-sensitive layer using this configuration will be described in detail below.

[0183] Another embodiment of the pressure-sensitive layer of the present invention can be configured as having a colorimetric layer comprising an electron-accepting compound and a polymer matrix, and a color-emitting layer comprising microcapsules. The pressure-sensitive layer employing this embodiment will be described in detail using the pressure-sensitive layer of the second embodiment described below as an example.

[0184] <Method 1>

[0185] The first aspect of the pressure-sensitive layer of the present invention is a pressure-sensitive layer in which microcapsules and electron-accepting compounds are contained in a polymer matrix.

[0186] The details regarding the components (specific polymeric compounds, microcapsules, electron-accepting compounds, etc.) applicable to the pressure-sensitive layer involved in the first method are the same as those described above, and the preferred method is also the same.

[0187] In this invention, "containing a component in a polymer matrix" means that the component is contained in the pressure-sensitive layer in a state in which at least a portion of the component is in contact with a specific polymer compound. The containing state can be either dispersed or dissolved, and in the case of a solid, it can also be a state in which a portion of it is exposed on the surface of the pressure-sensitive layer.

[0188] Specifically, in the case of microcapsules, the microcapsules of the present invention include both a state in which the entire microcapsule is contained within the pressure-sensitive layer within a polymer matrix, and a state in which a portion of the capsule wall of the microcapsule is exposed on the surface of the pressure-sensitive layer. Here, the state in which the entire microcapsule is in contact with the specific polymer compound includes both a state in which the microcapsule itself, composed of the inclusions and the wall material, is in direct contact with the specific polymer compound, and a state in which the microcapsule is in contact with the specific polymer compound via a dispersant.

[0189] Appropriate reference Figure 2 An example of a pressure measuring material having the pressure-sensitive layer involved in the first method will be described.

[0190] Figure 2 This is a schematic cross-sectional view showing an example of a pressure-measuring material having the pressure-sensitive layer involved in the first method. Additionally, Figure 2 This is a diagram used to illustrate Method 1. The components shown in the diagram do not correspond to their actual size and proportions.

[0191] exist Figure 2 In the pressure measuring material 10 shown, a pressure-sensitive layer 14 is disposed on a substrate 12. The pressure-sensitive layer 14 has microcapsules 18 and an electron-accepting compound 15. 18a represents the capsule wall of the microcapsule, and 18b represents the contents of the microcapsule (i.e., the core material). 16 represents a polymer matrix containing a specific polymer compound (not shown).

[0192] The pressure measuring material having the pressure-sensitive layer involved in the first method is particularly preferred to be usable in a pressure range of 500 MPa or higher.

[0193] From the viewpoint of excellent layering in high-pressure regions above 500 MPa, the arithmetic mean roughness Ra of the pressure measurement material involved in the first method is preferably less than 2.0 μm. In other words, this means that most of the microcapsules and electron-accepting compounds are preferably not exposed on the surface of the pressure-sensitive layer but are located in the polymer matrix.

[0194] In this invention, the arithmetic mean roughness Ra of the material used for pressure measurement refers to the arithmetic mean roughness Ra specified in JIS B 0681-6:2014. Furthermore, as the measuring device, a scanning white interferometer utilizing optical interference is used (specifically, a NewView5020 manufactured by Zygo Corporation: Stich mode; objective lens × 50x; intermediate lens × 0.5x).

[0195] The aforementioned arithmetic mean roughness Ra corresponds to the arithmetic mean roughness Ra of the surface on the side opposite to the substrate side. The arithmetic mean roughness Ra of the pressure measuring material involved in the first embodiment is preferably 0 μm or more and less than 2.0 μm, more preferably 0 μm to 1.0 μm, and even more preferably 0 μm to 0.5 μm.

[0196] As a method to make the arithmetic mean roughness Ra less than 2.0 μm, one can include increasing the amount of a specific polymer compound in the pressure-sensitive layer. The specific polymer compound is preferably 20% by mass or more relative to the total solid content constituting the pressure-sensitive layer.

[0197] From the viewpoint of excellent layering in high-pressure regions above 500 MPa, the preferred porosity of the pressure-measuring material having the pressure-sensitive layer involved in the first method is 5 mL / m. 2 The following applies. When the porosity is low, the microcapsules are difficult to rupture before being pressurized to over 500 MPa and are easily resistant. The preferred porosity is 0 mL / m³. 2 ~5mL / m 2 More preferably 0 mL / m 2 ~3mL / m 2 Further preferred is 0 mL / m 2 ~1mL / m 2 .

[0198] Here, the void volume is calculated using the following formula.

[0199] The mass (m1) of a pressure measuring material cut to 10cm × 10cm was measured. Next, diethylene glycol was impregnated through the surface of the pressure measuring material on the side with the pressure-sensitive layer. After wiping away any remaining diethylene glycol on the surface, the mass (m2) was measured. Furthermore, if X = m2 - m1, the porosity can be calculated using the following formula. Additionally, the density of diethylene glycol is 1.118.

[0200] Void volume (m1 / m2) = 100 × X ÷ 1.118

[0201] From the viewpoint of reducing porosity, the electron-accepting compound contained in the pressure-sensitive layer of the first embodiment preferably contains an organic compound, more preferably as a main component, and even more preferably has a content of 50% to 100% by mass. As preferred electron-accepting compounds, compounds similar to those described above can be cited, preferably containing a metal salt of an aromatic carboxylic acid, and particularly preferably containing a metal salt of salicylic acid. Furthermore, in this specification, "containing as a main component" refers to the component with the highest content in the electron-accepting compound.

[0202] From the viewpoint of superior layering in the high-pressure region, the content (volume fraction) of microcapsules relative to the pressure-sensitive layer is preferably 10 vol% to 80 vol%, more preferably 20 vol% to 60 vol%, and even more preferably 30 vol% to 60 vol%.

[0203] The content (volume fraction) of microcapsules relative to the pressure-sensitive layer can be determined by the following method. (Reference) Figure 2 Please provide an explanation.

[0204] A cross-sectional section of the material 10 used for pressure measurement was prepared and observed at 1000x magnification using a scanning electron microscope (SEM). From the SEM image of the cross-section, the interior (inclusion 18b) of the observed microcapsules 18 and the polymer matrix 16 containing the capsule wall 18a, a specific polymer compound (not shown), and the matrix containing the electron-accepting compound 15 could be distinguished. For all microcapsules 18 present in the observed field of view, the interior (inclusion 18b) of the microcapsules 18 was separated from the polymer matrix 16 containing the capsule wall 18a, the specific polymer compound, and the matrix containing the electron-accepting compound 15 by image analysis. The area of ​​the interior of the microcapsules and the area of ​​the aforementioned matrix were calculated separately, and the content A (area %) of the interior of the microcapsules was determined based on this ratio. Next, a further cross-sectional section was prepared in a direction orthogonal to the above cross-sectional section and orthogonal to the substrate, and the content B (area %) of the interior of the microcapsules was determined in the same manner. The average value of the content A (area %) and the content B (area %) of the interior of the microcapsules was calculated. The operation is performed at two randomly selected locations, and the average of the values ​​obtained at the two locations is taken as the content (volume %) of the microcapsules.

[0205] - Microcapsule particle size d1-

[0206] In Method 1, "the particle size d1 of the microcapsule" refers to the median particle size of the volume standard.

[0207] The median particle size of the microcapsule volume standard refers to the diameter (DSO) of particles on the large-diameter side and the small-diameter side when the total volume of the entire microcapsule contained in the pressure-sensitive layer is divided into two parts with a threshold of 50% of the total volume.

[0208] The median particle size of the microcapsule volume standard is calculated by coating the microcapsule liquid onto a support, photographing the surface of the dried coating film using an optical microscope at 150x magnification, and measuring the size of all microcapsules within a 2cm × 2cm area.

[0209] From the viewpoint of color development in high-pressure regions (preferably 100MPa to 10000MPa, more preferably 300MPa to 3000MPa), the particle size d1 of the microcapsules is preferably 1μm to 50μm, more preferably 5μm to 30μm.

[0210] From the perspective of balancing the height of the pressure measurement and the color concentration, the ratio of the thickness t of the pressure-sensitive layer to the particle size d1 of the microcapsules contained in the pressure-sensitive layer preferably satisfies the relationship shown in Equation 1 below.

[0211] 1 < t / d1 < 5……Equation 1

[0212] When t / d1 < 5, better color development can be obtained, and when 1 < t / d1, the suppression of haze becomes easier.

[0213] -Inner diameter p1 of the microcapsule-

[0214] From the perspective of superior hierarchical structure in high-pressure regions and color development in high-pressure regions, the inner diameter p1 of the microcapsules is preferably 0.5 μm to 50 μm, more preferably 1 μm to 30 μm, and even more preferably 2 μm to 20 μm.

[0215] In method 1, the "inner diameter p1 of the microcapsule" is determined using the following method. (See reference...) Figure 2 Please provide an explanation.

[0216] A cross-sectional section of the material 10 used for pressure measurement was prepared and observed at 1000x magnification using a scanning electron microscope (SEM). From the SEM image of the cross-section, the interior of the observed microcapsule 18 (inclusions 18b) and the polymer matrix 16 containing the capsule wall 18a, a specific polymer compound, and the matrix containing the electron-accepting compound 15 could be distinguished. Among the microcapsules 18 present in the observed field of view, the major axis (inner diameter) of 10 microcapsules was measured sequentially starting from the largest microcapsule, and the arithmetic mean of these measurements was calculated to obtain the average value. This operation was performed in 5 fields of view, and the average of the average values ​​obtained at each location was calculated. This value was taken as the average inner diameter of the microcapsule. The major axis refers to the longest inner diameter observed when the microcapsule is viewed.

[0217] <Method 2>

[0218] The second aspect of the pressure-sensitive layer of the present invention is a pressure-sensitive layer comprising a color-developing layer having an electron-accepting compound and a polymer matrix and a color-emitting layer having microcapsules, wherein a substrate, a color-developing layer and a color-emitting layer are sequentially comprising, and the thickness of the color-emitting layer is less than half the thickness of the color-developing layer.

[0219] The details regarding the components (specific polymeric compounds, microcapsules, electron-accepting compounds, etc.) applicable to the pressure-sensitive layer involved in the second method are the same as those described above, and the preferred method is also the same.

[0220] An example of a pressure measuring material having the pressure-sensitive layer involved in the second method will be illustrated using the accompanying drawings.

[0221] Figure 3 This is a schematic cross-sectional view showing an example of a pressure-measuring material having the pressure-sensitive layer involved in the second method. Additionally, Figure 3 This is a diagram used to illustrate the second method. The components shown in the diagram do not correspond to their actual size and proportions.

[0222] exist Figure 3 In the pressure measuring material 20 shown, a pressure-sensitive layer 24 is disposed on a substrate 22. It is formed of a chromogenic layer 24a and a color-developing layer 24b. The chromogenic layer 24a has microcapsules 28, and the color-developing layer 24b has a polymer matrix 26 containing an electron-accepting compound 25 and a specific polymer compound. 28a represents the capsule wall of the microcapsules, and 28b represents the contents of the microcapsules (i.e., the core material). The chromogenic layer 24a preferably contains a specific polymer compound.

[0223] From the viewpoint of achieving superior layering in high-pressure regions above 100 MPa, the thickness of the color-developing layer is preferably less than half the thickness of the color-developing layer, more preferably less than one-third. There is no particular limitation on the lower limit. In one aspect of the invention, the thickness of the color-developing layer is preferably 0.001 to 0.5 times, more preferably 0.001 to 0.4 times, and even more preferably 0.001 to 0.33 times, relative to the thickness of the color-developing layer.

[0224] The thickness of the chromogenic layer and the developing layer can be measured by microscopic observation.

[0225] Specifically, a cross-sectional section is prepared by vertically cutting the material to be measured for pressure measurement. This cross-sectional section is then observed using a scanning electron microscope (SEM) with a field of view of 800 μm × 600 μm. From this image, the thicknesses of the chromophore and chromogenic layers are measured at 10 locations at 50 μm intervals, and the arithmetic mean of these measurements is taken as the thickness of the chromophore and chromogenic layers. An example of a scanning electron microscope is the "Miniscope™ 3030Plus" tabletop microscope (manufactured by Hitachi High-Technologies Corporation).

[0226] In addition, such as Figure 3 As shown, the chromophore is defined as 0 μm in the presence or absence of microcapsules.

[0227] The second method is particularly preferred as it can be used in a pressure range of 100 MPa to 500 MPa. From the viewpoint of excellent layering in the high-pressure region of 100 MPa to 500 MPa, the porosity of the pressure measuring material containing the pressure-sensitive layer involved in the second method is preferably 5 mL / m. 2 ~20mL / m 2 More preferably, exceeding 8 mL / m 2 And 15mL / m 2 The void volume is calculated using the formula above.

[0228] From the viewpoint of keeping the porosity within a specific range, the electron-accepting compound in the second embodiment preferably contains inorganic particles, more preferably as a main component, and even more preferably contains 50% to 100% by mass. As a preferred electron-accepting compound, compounds similar to those described above can be cited, and it is preferable to contain acidic clay or activated clay. The electron-accepting compound in the second embodiment may be primarily inorganic particles, or it may contain other electron-accepting compounds.

[0229] From the viewpoint of excellent layering in the high-pressure region of 100MPa to 500MPa, the varistor in the second embodiment preferably contains inorganic particles other than electron-accepting compounds. Examples of inorganic particles other than electron-accepting compounds include particles similar to those described above, with silicon dioxide being the most preferred.

[0230] From the viewpoint of superior layering in the high-pressure region of 100MPa to 500MPa, the pressure-sensitive layer (preferably the color-developing layer) in the second embodiment preferably contains inorganic particles that are electron-accepting compounds and inorganic particles that are not electron-accepting compounds. By simultaneously containing inorganic particles that are electron-accepting compounds and inorganic particles that are not electron-accepting compounds, the probability of contact between the electron-donating dye precursor flowing out of the microcapsule and the electron-accepting compound can be suppressed while maintaining the porosity within a specific range. Therefore, it can be used as a material suitable for layering in the high-pressure region of 100MPa to 500MPa.

[0231] From the viewpoint of excellent hierarchical structure in the high-pressure region of 100MPa to 500MPa, the arithmetic mean roughness Ra of the pressure measurement material involved in the second method is preferably 2.0μm to 10.0μm.

[0232] The aforementioned arithmetic mean roughness Ra corresponds to the arithmetic mean roughness Ra of the surface on the side opposite to the substrate side. The arithmetic mean roughness Ra of the pressure measuring material involved in the second method is preferably 2.0 μm to 8.0 μm, more preferably 2.0 μm to 5.0 μm.

[0233] As a method for adjusting the arithmetic mean roughness Ra to 2.0 μm to 10.0 μm, for example, the methods shown in (1) and (2) below, as well as methods combining them, can be cited.

[0234] (1) Methods to thin the hair color layer

[0235] Since the microcapsules are not disposed on the entire surface of the pressure-sensitive layer, the presence or absence of microcapsules on the surface of the pressure-sensitive layer is a method that can adjust the surface roughness.

[0236] (2) Methods to increase the amount of inorganic particles in the developing layer

[0237] It is a method that uses the difference between the positions where inorganic particles are present and the positions where they are not present to adjust the surface roughness of the color development layer.

[0238] In particular, when the amount of inorganic particles (the total amount of inorganic particles that are electron-accepting compounds and inorganic particles that are not electron-accepting compounds) is greater than the total amount of the specific polymeric compounds present in the chromogenic layer, particles appear on the surface of the chromogenic layer, thus making the surface of the chromogenic layer prone to roughness. Furthermore, when the microcapsules and specific polymeric compounds are arranged in a thin layer, the microcapsules enter the recesses of the roughened chromogenic layer, resulting in the arithmetic mean roughness Ra of the pressure measurement material easily becoming 2.0 μm to 10.0 μm.

[0239] In the above-mentioned state where the arithmetic mean roughness Ra is 2.0 μm to 10.0 μm, microcapsules that do not rupture even under high pressure are present in the recesses of the color development layer, or in areas where microcapsules are not present on the surface. Therefore, it is believed that the material for pressure measurement in the second manner can be suitable for high pressure regions of 100 MPa to 500 MPa.

[0240] Furthermore, in the second approach, it is preferable that the microcapsules are not present on the entire surface of the pressure-sensitive layer on the side opposite to the substrate side, and the proportion of microcapsules is preferably 95% or less, more preferably 90% or less.

[0241] As a method for determining the proportion of the aforementioned microcapsules, firstly, the total number of microcapsules observed in the field of view is determined by observing the surface of the chromophore from any position using a laser microscope (KEYENCE VK-8510, field of view size: 100μm×150μm). Then, the area of ​​the number of microcapsules observed in the field of view is calculated by image analysis and divided by the field of view area.

[0242] From the viewpoint that microcapsules can easily enter the recesses of the color developing layer and that the layering of the high-pressure region of 100 MPa to 500 MPa is excellent, the total solid content of the color developing layer forming composition is preferably less than the total solid content of the color developing layer forming composition. Preferably, the total solid content of the color developing layer forming composition is 0.001 to 0.45 times that of the color developing layer forming composition, more preferably 0.005 to 0.25 times.

[0243] - Microcapsule particle size d2-

[0244] In the second method, "the particle size d2 of the microcapsule" refers to the average particle size.

[0245] As a method for determining the average particle size of microcapsules, images taken from the surface of the chromophore layer containing microcapsules were analyzed using an optical microscope (OLYMPUS BX60, field of view size: 320 μm × 450 μm). The major diameter (particle size) of 30 microcapsules was measured sequentially, starting with the largest microcapsule, and these measurements were arithmetically averaged to obtain the average value. This operation was performed at any five locations (five fields of view) in the first layer, and the average of the values ​​obtained at each location was calculated. This value was taken as the average particle size of the microcapsules. The major diameter refers to the longest diameter observed when the microcapsule is viewed.

[0246] From the viewpoint of color development in high-pressure regions (preferably 100MPa to 10000MPa, more preferably 300MPa to 3000MPa), the particle size d2 of the microcapsules is preferably 1μm to 50μm, more preferably 5μm to 30μm.

[0247] The inner diameter p2 of a microcapsule

[0248] From the viewpoints of superior hierarchical structure in the high-pressure region of 100MPa to 500MPa and color development in the high-pressure region, the inner diameter p2 of the microcapsule is preferably 1μm to 50μm, more preferably 2μm to 20μm, and even more preferably 2μm to 15μm.

[0249] In the second method, the value of "inner diameter p2 of the microcapsule" is obtained by the following method.

[0250] First, the wall thickness of the microcapsules is determined. The wall thickness of a microcapsule refers to the thickness (μm) of the capsule wall of the microcapsule particles forming the microcapsule. The number-average wall thickness is the average value obtained by averaging the wall thickness (μm) of five individual microcapsules obtained using a scanning electron microscope (SEM). More specifically, cross-sectional sections of microcapsules present in the pressure measurement material are prepared. These sections are observed using an SEM at 15000x magnification. Five microcapsules with a major axis ranging from (average microcapsule diameter) × 0.9 to (average microcapsule diameter) × 1.1 are selected. The cross-sections of each selected microcapsule are observed, and the capsule wall thickness is determined. The average value is then calculated. The major axis refers to the longest diameter observed when the microcapsule is viewed. Furthermore, the inner diameter of the microcapsule is calculated by dividing the average particle diameter by twice the wall thickness.

[0251] <Formation of Pressure-Sensitive Layer>

[0252] The formation of the pressure-sensitive layer is not particularly limited as long as it is based on the process of forming the pressure-sensitive layer. The pressure-sensitive layer contains: a polymer matrix having a polymer compound with a molecular weight of 1000 or more (a specific polymer compound); microcapsules containing an electron-donating dye precursor and a solvent; and an electron-accepting compound.

[0253] In the first method, a pressure-sensitive layer can be formed by preparing a composition, applying it (e.g., coating) to a substrate, and drying it.

[0254] That is, the pressure measuring material having the pressure-sensitive layer of the first type is preferably obtained by a manufacturing method including a step of disposing a pressure-sensitive layer forming composition on a substrate, the pressure-sensitive layer forming composition comprising: a polymer matrix containing a specific polymer compound; microcapsules containing an electron-donating dye precursor and a solvent; and an electron-accepting compound.

[0255] The pressure-sensitive layer forming composition for forming the pressure-sensitive layer of the first type can be prepared, for example, by mixing a dispersion of microcapsules, a solution (or emulsion) of a specific polymer compound (the polymer compound forming the polymer matrix), an electron-accepting compound, and other arbitrary components (e.g., oil-absorbing particles).

[0256] Furthermore, in the second method, the pressure-sensitive layer can be formed, for example, as follows: a pressure-sensitive layer forming composition is prepared by combining a color-developing layer forming composition and a color-developing layer forming composition; the color-developing layer forming composition is applied (e.g., coated) onto a substrate; the color-developing layer forming composition is then applied (e.g., coated) onto the substrate and dried. The color-developing layer forming composition can be prepared, for example, by preparing a dispersion of microcapsules, mixing the obtained dispersion, a solution (or emulsion) of a specific polymeric compound, and other arbitrary components (e.g., surfactants, etc.). The color-developing layer forming composition can be prepared, for example, by mixing an electron-accepting compound, a solution (or emulsion) of a specific polymeric compound, and other arbitrary components (e.g., inorganic particles, etc.).

[0257] That is, the pressure measuring material having the pressure-sensitive layer of the second type is preferably obtained by the following manufacturing method, which includes the following steps: obtaining a color-forming layer forming composition containing microcapsules containing an electron-donating dye precursor and a solvent (preferably a solvent with a boiling point of 130°C or higher) and a solvent (preferably a solvent with a boiling point of 130°C or lower); obtaining a color-developing layer forming composition containing an electron-accepting compound and a polymer compound (specific polymer compound) with a molecular weight of 1000 or higher; forming a color-developing layer by disposing the above-mentioned color-developing layer forming composition on a substrate; and forming a color-developing layer by disposing the above-mentioned color-developing layer forming composition on the above-mentioned color-developing layer.

[0258] Furthermore, the color-forming composition preferably contains a polymeric compound with a molecular weight of 1000 or more (a specific polymeric compound).

[0259] The specific polymeric compound contained in the chromogenic layer forming composition and the specific polymeric compound preferably contained in the chromogenic layer forming composition may each be only one type, or two or more types may be combined. Furthermore, the specific polymeric compound contained in the chromogenic layer forming composition and the specific polymeric compound preferably contained in the chromogenic layer forming composition may be the same polymeric compound or different polymeric compounds.

[0260] The specific preparation method, coating amount, drying conditions, etc. of the pressure-sensitive layer forming composition in the formation of the pressure-sensitive layer can be appropriately determined according to the types of components contained in the pressure-sensitive layer forming composition and the specific method of the material used for target pressure measurement.

[0261] When a pressure-sensitive layer is formed by coating a composition onto a substrate, the coating can be performed using a known coating method. Examples of coating methods include those using an air knife coater, a rod coater, a bar coater, a curtain coater, a gravure coater, an extrusion coater, a die coater, a slip bead coater, and a doctor blade coater.

[0262] [Other layers]

[0263] The pressure measuring material of the present invention may also have other layers on the substrate besides the pressure-sensitive layer.

[0264] Other types of layers include protective layers, white layers, and easy-to-adhere layers.

[0265] -Protective Layer-

[0266] The pressure measuring material of the present invention may also have a protective layer on the side of the pressure-sensitive layer opposite to the side having the substrate. The pressure measuring material of the present invention can have a protective layer as the outermost layer, but is not limited to this method.

[0267] Because high pressure is applied to the pressure measuring material of the present invention, there is a tendency for the solvent (oil component) contained in the microcapsules to easily leach out to the outside of the pressure-sensitive layer. This leaching of the oil component causes oil contamination, which is therefore undesirable. In contrast, by having a protective layer, the leaching of the oil component to the outside of the pressure-sensitive layer can be effectively suppressed.

[0268] Therefore, the protective layer is preferably a layer with low permeability to oil components.

[0269] A protective layer can be formed by attaching a sheet or film to the pressure-sensitive layer.

[0270] When a protective layer is provided by attaching a protective layer forming sheet or film, the desired protective layer forming sheet or film is prepared and attached to the pressure-sensitive layer by a known method (e.g., using adhesive).

[0271] There are no particular restrictions on the thickness of the protective layer; it can be selected according to the purpose, etc.

[0272] The thickness of the protective layer is preferably 0.1 μm to 50 μm, more preferably 0.5 μm to 10 μm.

[0273] -White layer-

[0274] The pressure measuring material of the present invention may also have a white layer between the substrate and the pressure-sensitive layer.

[0275] By having a white layer, the contrast between the colored and uncolored parts can be increased, thereby improving visual recognition.

[0276] The white layer can be a coating layer formed between the substrate and the pressure-sensitive layer using a white layer forming composition, or it can be a layer formed by adhering a white layer forming sheet or film to the substrate before it is applied to the pressure-sensitive layer.

[0277] The white layer can be provided, for example, as a layer containing known white pigments (e.g., white dyes), resin components, etc.

[0278] Specifically, examples of white pigments include titanium dioxide, zinc oxide, and calcium carbonate.

[0279] The white layer is the layer that does not contain the aforementioned microcapsules and / or electron-accepting compounds.

[0280] When a white layer is formed by coating a white layer-forming composition, for example, the white layer-forming composition is prepared, applied (e.g., coated) onto a substrate, and then dried. As a coating method in this case, the same method as described above for the pressure-sensitive layer can be used.

[0281] When a white layer is formed by pasting a sheet or film for forming a white layer, the desired sheet or film for forming a white layer is prepared and pasted onto a substrate by a known method (e.g., using an adhesive).

[0282] -Easy-to-adhere layer-

[0283] To improve the adhesion between the substrate and the pressure-sensitive layer, an easy-to-adhere layer is preferably provided.

[0284] When an easy-to-adhere layer is present, the pressure measuring material of the present invention preferably has at least a substrate, an easy-to-adhere layer and a pressure-sensitive layer in sequence.

[0285] In the case of having an easy-to-adhere layer and a white layer, it is preferable to have a substrate, an easy-to-adhere layer, a white layer and a pressure-sensitive layer in sequence.

[0286] The easy-to-adhesive layer is a layer that does not contain the aforementioned microcapsules and / or electron-accepting compounds.

[0287] From the viewpoint of improving the adhesion between the substrate and the pressure-sensitive layer and the polymer matrix, the easy-to-adhere layer preferably has a resin.

[0288] Examples of resins include acrylate resins, polyurethane resins, styrene resins, and vinyl resins.

[0289] The easy-to-bond layer can also be a layer containing polyurethane polymers, end-capped isocyanates, etc.

[0290] Easy-adhesive layers can be formed by bonding a substrate to a sheet or film with easy-adhesive properties, or by coating an easy-adhesive layer onto a substrate to form a composition.

[0291] There are no particular limitations on the thickness of the easy-to-bond layer, and it can be selected according to the purpose, etc.

[0292] The thickness of the easy-to-adhere layer is preferably 0.005μm to 1.0μm, more preferably 0.005μm to 0.5μm, even more preferably 0.005μm to 0.2μm, and even more preferably 0.01μm to 0.1μm.

[0293] (Thickness of the material used for pressure measurement)

[0294] The thickness of the material used for pressure measurement in this invention is not particularly limited, but is preferably 10 μm to 800 μm, and more preferably 10 μm to 500 μm.

[0295] -Thickness T-

[0296] The thickness T of the layer, which is the thickness of the material used for pressure measurement minus the thickness of the substrate, is preferably 1 μm to 250 μm, more preferably 3 μm to 200 μm, and even more preferably 5 μm to 150 μm.

[0297] The thickness T can be measured using the same method as the thickness t of the pressure-sensitive layer described above.

[0298] Specifically, the thickness of the pressure measuring material and the substrate can be measured at 10 randomly selected locations, and the calculated values ​​are obtained by arithmetic averaging based on the difference between the thickness of the pressure measuring material and the thickness of the substrate.

[0299] (Arithmetic mean roughness Ra of the material used for pressure measurement)

[0300] The arithmetic mean roughness Ra of the material used for pressure measurement is preferably 10.0 μm or less.

[0301] The preferred ranges for the arithmetic mean roughness Ra when the pressure-sensitive layer is in the first and second modes are as described above.

[0302] The arithmetic mean roughness Ra described above corresponds to the arithmetic mean roughness Ra of the surface on the side opposite to the substrate side. The method for measuring the arithmetic mean roughness Ra is as described above.

[0303] (The ratio of thickness T to the inner diameter p of the microcapsule)

[0304] The ratio T / p of the thickness T in the material used for pressure measurement to the inner diameter p of the microcapsules is preferably 1.2 or more, more preferably 1.3 or more. When T / p is 1.2 or more, the layering of the high-pressure region of 100 MPa or more is more superior. More preferably, it is 1.2 to 5.

[0305] In the case of the pressure-sensitive layer of the first type, the ratio of thickness T to inner diameter p1 of the microcapsule, T / p1, is preferably 5 or less, more preferably 1.2 to 5, and even more preferably 1.2 to 3.

[0306] In the case of the pressure-sensitive layer of the second type, the ratio of thickness T to inner diameter p2 of the microcapsule, T / p2, is preferably 5 or less, more preferably 1.2 to 5, and even more preferably 1.3 to 5.

[0307] <Matters related to pressure measurement>

[0308] Pressure measurement using the pressure measuring material of the present invention can be performed by placing the pressure measuring material at the location where the pressure or pressure distribution is measured, and then applying pressure to the pressure measuring material in this state.

[0309] As a pressure, it can be any of point pressure, line pressure, or surface pressure.

[0310] In the case of color development, the concentration difference (ΔD) between the concentration after color development when pressure is applied at 1000 MPa and the concentration after color development when pressure is applied at 2000 MPa is preferably 0.6 or more.

[0311] When ΔD exceeds 0.6, the pressure measurement material of the present invention can be used as a pressure measurement material with better reproduction of concentration and concentration level that can be visually identified or read when color is emitted under pressure.

[0312] When the pressure-measuring material with the pressure-sensitive layer of the first method described above is colored, the concentration difference (ΔD1) between the concentration after color development when pressure is applied at 2000 MPa and the concentration after color development when pressure is applied at 1000 MPa is preferably 0.1 or more, and more preferably 0.4 or more.

[0313] When ΔD1 is 0.1 or higher (preferably 0.4 or higher), the pressure measurement material of this method can be used as a pressure measurement material with better reproduction of concentration and concentration level that can be visually identified or read when color is emitted under pressure of 500 MPa or higher.

[0314] When the pressure-measuring material with the pressure-sensitive layer of the second method described above is colored, the concentration difference (ΔD2) between the concentration after color development when pressure is applied at 500 MPa and the concentration after color development when pressure is applied at 100 MPa is preferably 0.1 or more, and more preferably 0.4 or more.

[0315] When ΔD2 is 0.1 or higher (preferably 0.4 or higher), the pressure measurement material of this method can be used as a pressure measurement material with better reproduction of concentration and concentration level that can be visually identified or read when color is emitted under pressure of 100 MPa to 500 MPa.

[0316] Color intensity is a value measured using a reflectance density meter (e.g., the RD-19I manufactured by GretagMacbeth LLC).

[0317] Furthermore, the pressure measurement material of the present invention preferably exhibits the property that the color concentration increases with increasing pressure when a pressure of 100 MPa to 10000 MPa (more preferably 100 MPa to 3000 MPa) is applied, i.e., the color gradation.

[0318] In the pressure measurement material of the present invention, the preferred color gradation is the property that the color concentration increases linearly with increasing pressure (i.e., pressure is proportional to color concentration).

[0319] The pressure measuring material of the present invention can be configured to include the aforementioned pressure range, depending on the application of the measurement. For example, one embodiment of the pressure measuring material of the present invention is for pressure measurement in a range exceeding 1000 MPa (e.g., 1000 MPa to 3000 MPa, preferably 1000 MPa to 2000 MPa). Furthermore, another embodiment of the pressure measuring material of the present invention is for pressure measurement in a pressure range exceeding 1000 MPa (e.g., 100 MPa to 500 MPa).

[0320] The applications of the pressure measuring material of the present invention include the following examples in various fields, but are not limited thereto. Furthermore, the following examples are sometimes repeated.

[0321] Examples include the manufacture of automobiles and other vehicles or aircraft (e.g., confirmation of pressure distribution during molding of various components, bodywork, etc., or assembly of components), construction (e.g., confirmation of pressure distribution during the assembly of building materials), the manufacture of electronic products (e.g., confirmation of pressure distribution during curved surface processing (e.g., bonding of curved displays, etc.), transportation (e.g., confirmation of impact forces applied to goods during transportation), metal processing (e.g., confirmation of mold contact during the manufacture of various metal products), molding of resin products (e.g., confirmation of mold contact during the molding of resin products), molding of pharmaceuticals (e.g., confirmation of pressure distribution during tablet compression), furniture (e.g., confirmation of pressure distribution on furniture surfaces (chairs, sofa seats, etc.), stationery (e.g., confirmation of gripping forces applied to writing instruments, etc.), and sporting goods (e.g., confirmation of impact forces applied to articles made of elastic materials (balls, etc.)).

[0322] Example

[0323] The present invention will now be described in more detail through examples. The invention is not limited to these examples unless it departs from its spirit. Furthermore, unless otherwise specified, "%" and "parts" are weight measurements.

[0324] (Example 1)

[0325] <Preparation of microcapsule liquid (A) containing electron-donating dye precursor>

[0326] Ten parts of the following compound (A), which is used as an electron-donating dye precursor, were dissolved in 53 parts of a linear alkylbenzene (JxEnergy Corporation, grade olefin L, boiling point above 130°C) to obtain solution A.

[0327] Next, 0.4 parts of N,N,N',N'-tetratetra(2-hydroxypropyl)ethylenediamine (ADEKACORPORATION, ADEKA POLYETHER EDP-300) dissolved in 14 parts of synthetic isoparaffin (Idemitsu Kosan Co., Ltd., IP SOLVENT 1620, boiling point above 130°C) and 1.2 parts of ethyl acetate were added to solution A while it was being stirred to obtain solution B.

[0328] Furthermore, 18 parts of the trimethylolpropane adduct of toluene diisocyanate (DICCorporation, Bernock D-750) dissolved in 3 parts of ethyl acetate were added to solution B while it was being stirred to obtain solution C.

[0329] Furthermore, solution C was added to a solution in which 8 parts of polyvinyl alcohol (PVA-205, KURARAY CO., LTD., number average molecular weight 25,000, dispersant) were dissolved in 110 parts of water, and emulsification and dispersion were carried out. 340 parts of water were added to the emulsion after emulsification and dispersion, and the mixture was heated to 70°C while stirring, stirred for 1 hour, and then cooled.

[0330] Water was added to the cooled liquid to adjust the concentration, resulting in a microcapsule liquid (A) containing an electron-donating dye precursor with a solid content of 25%.

[0331] [Chemical Formula 1]

[0332]

[0333] The median particle size (D50) of the obtained microcapsules on a volume basis was 11 μm.

[0334] The median particle size on a volumetric basis was determined using a Microtrac MT3300EXII (manufactured by Nikkiso Co., Ltd.).

[0335] <Preparation of Pressure Testing Plate (A)>

[0336] To 20 parts of the microcapsule solution (A) obtained above, 11 parts of a 40% dispersion of zinc 3,5-bis(α-methylbenzyl)salicylate, an electron acceptor compound used as a colorimetric agent, and 20 parts of a 20% aqueous solution of polyvinyl alcohol (PVA-105, KURARAY CO., LTD., number average molecular weight 22,000), a specific polymer compound used to form a polymer matrix, a pressure-sensitive layer forming composition (A) was obtained.

[0337] The obtained pressure-sensitive layer forming composition (A) was coated onto a 75 μm thick PET substrate (A4300: manufactured by Toyobo Co., Ltd.) with a film thickness of 15 μm after drying using a bar coater, and dried at 80°C to obtain a pressure measuring sheet (A) with a pressure-sensitive layer on a PET substrate (pressure measuring material).

[0338] Using a miniscope "Miniscope TM3030Plus" (manufactured by Hitachi High-Technologies Corporation), the cross-section of the pressure measuring sheet (A) cut vertically was observed at 10 arbitrary locations. The thickness of the pressure measuring sheet (A) and the thickness of the PET substrate were measured. The thickness of the pressure-sensitive layer (film thickness) was calculated by arithmetically averaging the differences between the calculated thickness of the pressure measuring sheet (A) and the thickness of the PET substrate. The thickness of the pressure-sensitive layer (film thickness) was confirmed to be 15 μm.

[0339] The ratio of the thickness t of the pressure-sensitive layer to the particle size d of the microcapsules (t / d) is 1.36.

[0340] The martensitic hardness of polyvinyl alcohol (PVA-105, KURARAY CO., LTD.), which forms the polymer matrix, was determined using a FISCHER INSTRUMENTS KK HM2000 microhardness tester. In the test, a diamond indenter (Berkovich indenter) was used in a laboratory environment of 23°C and 50% RH. First, a load of 0 mN to the maximum test load was applied for 10 seconds. Then, the maximum test load was maintained for 5 seconds, and finally, the load was unloaded for 10 seconds, reducing the maximum test load to 0 mN. The martensitic hardness (N / mm²) was calculated by dividing the maximum test load by the indenter surface area at the maximum indentation depth. 2 ).

[0341] For a 5 μm thick polymer matrix (PVA105) film deposited on a glass substrate, the Martens hardness measured at the maximum test load with a maximum indentation depth of 0.5 μm is 165 N / mm. 2 .

[0342] <Hair color rating: A>

[0343] The pressure measuring plate (A) of Example 1 obtained above was cut into 4 samples of 9cm to 11cm.

[0344] Each sample was pressurized using any of the pressures shown in the pressure column of Table 1 below, and it was confirmed that the samples developed color due to pressure. The pressurization was performed using a pressurizing machine (DSF-C1-A, manufactured by AIDA ENGINEERING, LTD.).

[0345] The chromatic concentration of the chromatic samples was determined using a spectrophotometer (X-Rite, Inc., X-Rite 504). The results are shown in the chromatic concentration column of Table 1.

[0346] and, Figure 1 The graph in the middle shows the relationship between pressure and color concentration.

[0347] [Table 1]

[0348]

[0349] As shown in Table 1 and Figure 1 As shown, it was confirmed that the pressure measuring sheet of Example 1 can achieve excellent color development with good gradation in high-pressure areas exceeding 1000 MPa.

[0350] (Example 2)

[0351] In the preparation of the pressure measuring sheet (A), a portion of the PVA-105 was replaced with a polyol polyalkylene alkyl ether surfactant (Noigen LP-90, manufactured by DKS Co. Ltd.). Otherwise, the pressure measuring sheet (pressure measuring material) of Example 2 was prepared in the same manner as in Example 1.

[0352] (Examples 3-8)

[0353] The composition of each material was changed as shown in Table 2. Otherwise, the pressure measuring plates of Examples 3 to 8 were prepared in the same manner as in Example 2.

[0354] In addition, microcapsule liquid (B) was prepared as follows.

[0355] <Preparation of microcapsule liquid (B) containing electron-donating dye precursor>

[0356] Solution A2 was obtained by dissolving 6 parts of 3',6'-bis(diethylamino)-2-(4-nitrophenyl)spiro[isoindole-1,9'-xanthophene]-3-one (manufactured by HODOGAYA CHEMICALCO., LTD., Pink-DCF) and 8 parts of 6'-(diethylamino)-1',3'-dimethylfluorane (manufactured by HODOGAYA CHEMICALCO., LTD., Orange-DCF) as an electron-donating dye precursor in 70 parts of Hisol SAS-296 (an oil component (solvent) manufactured by Nippon Oil Corporation; a mixture of 1-phenyl-1-dimethylamino) and 8 parts of 6'-(diethylamino)-1',3'-dimethylfluorane (manufactured by HODOGAYA CHEMICALCO., LTD., Orange-DCF). Next, 0.7 parts of N,N,N',N'-tetra(2-hydroxypropyl)ethylenediamine (ADEKA CORPORATION, ADEKA POLYETHEREDP-300) dissolved in 19 parts of synthetic isoparaffin (IdemitsuKosan Co., Ltd., IP SOLVENT 1620) and 2.5 parts of methyl ethyl ketone were added to solution A2 under stirring to obtain solution B2. Furthermore, 77 parts of trimethylolpropane adduct of toluene diisocyanate (DIC Corporation, Bernock D-750, containing 25% ethyl acetate) dissolved in 6 parts of ethyl acetate were added to solution B2 under stirring to obtain solution C2. Finally, solution C2 was added to a solution in which 10 parts of polyvinyl alcohol (KL-318, KURARAY CO., LTD.) were dissolved in 140 parts of water, and emulsification and dispersion were performed. 200 parts of water were added to the emulsion after emulsification and dispersion, and the mixture was heated to 70°C while stirring. After stirring for 1 hour, the mixture was cooled. Water was added to adjust the concentration to prepare a microcapsule solution (B) containing an electron-donating dye precursor with a solid component concentration of 20% by mass. The median particle size of the microcapsules was 8 μm.

[0357] (Comparative Example 1)

[0358] According to Example 1 of Japanese Patent Application Publication No. 2009-019949, a two-piece pressure measuring plate consisting of an electron-donating colorless dye plate and a color developer plate was manufactured.

[0359] [evaluate]

[0360] The porosity of the pressure-sensitive layer of each pressure measuring sheet in Examples 1 to 8 was measured.

[0361] Furthermore, the pressure measuring tablets of Examples 2-8 and Comparative Example 1 were evaluated using the following "concentration level evaluation A" and "color development evaluation B".

[0362] [Determination of porosity]

[0363] The pressure measuring sheets (PET films forming the pressure-sensitive layer) from Examples 1-8 were cut to 10cm × 10cm pieces, and their mass (m1) was measured. Next, diethylene glycol was placed on the surface of the side with the pressure-sensitive layer to impregnate it. After wiping away any residual diethylene glycol on the surface, its mass (m2) was measured. Furthermore, the void fraction was calculated using the formula X = m2 - m1. The density of diethylene glycol is 1.118.

[0364] Void volume (m1 / m2) = 100 × X ÷ 1.118

[0365] The porosity of each pressure measuring plate obtained in Examples 1-8 was 1 mL / m. 2 the following.

[0366] [Concentration Level Evaluation A (1000MPa~2000MPa)]

[0367] For the pressure measurement plates of Examples 1 to 8 and Comparative Example 1, the color concentration at 1000 MPa and 2000 MPa was measured, and the difference ΔD1 between the color concentration at 2000 MPa and the color concentration at 1000 MPa was calculated. The evaluation was carried out according to the following evaluation criteria.

[0368] The pressure application method and measuring device are the same as those used in the above color evaluation A.

[0369] In addition, "A" and "B" represent the ranges that are permissible in practical use, with "A" being the best. The results are shown in Table 2.

[0370] <Evaluation Criteria>

[0371] “A”: ΔD1 is 0.4 or higher.

[0372] “B”: ΔD1 is greater than 0.1 and less than 0.4.

[0373] “C”: ΔD1 is less than 0.1.

[0374] [Hair color rating: B]

[0375] For each pressure testing tablet of Examples 1-8 and Comparative Example 1, the colorimetric concentration at 1000 MPa obtained in the above concentration level evaluation A was evaluated according to the following evaluation criteria. The results are shown in Table 2.

[0376] <Evaluation Criteria>

[0377] “A”: Color concentration is 0.5 or higher.

[0378] “B”: Color concentration less than 0.5.

[0379]

[0380] In Table 2, T represents the thickness of the layer obtained by subtracting the thickness of the substrate from the thickness of the material used for pressure measurement, T / p1 represents the ratio of thickness T to the inner diameter p1 of the microcapsule, T / d1 represents the ratio of thickness T to the particle size d1 (median particle size) of the microcapsule, and Ra represents the arithmetic mean roughness of the outermost surface (pressure-sensitive layer surface) on the side opposite to the substrate. All of these values ​​were obtained by the above method.

[0381] In Table 2, "-" indicates that the corresponding component is not present or that the corresponding test item has not been performed.

[0382] (Example 9)

[0383] -Preparation of the colorimetric layer forming composition-

[0384] 100 parts of activated clay (Silton F-242, MIZUSAWA INDUSTRIAL CHEMICALS, LTD.) and 100 parts of amorphous silica (MIZUSAWA INDUSTRIAL CHEMICALS, LTD., Mizukasil P-78A, inorganic particles that are not electron acceptors) were mixed with 10 parts of 10% sodium hydroxide aqueous solution, 750 parts of water, and 1 part of sodium hexametaphosphate (Nippon Chemical Industrial CO., LTD.) and dispersed using a homogenizer. In addition, 140 parts of modified acrylate copolymer (Zeon Corporation, Nipol LX814, 47% solids concentration, specific polymer compound), 28 parts of anionic olefin resin (Arakawa Chemical Industries, Ltd., polymeron 482, 25% solids concentration, specific polymer compound), 5 parts of a 15% aqueous solution of linear alkylbenzene sulfonate amine salt (DKS Co. Ltd., Neugen T), 35 parts of a 1% aqueous solution of polyoxyethylene polyoxypropylene laurate ether (DKSCo. Ltd., Noigen LP-70), and 35 parts of a 1% aqueous solution of sodium-bis(3,3,4,4,5,5,6,6,6-nonafluorohexyl)-2-sulfanilamide (FUJIFILM Corporation, W-AHE) were mixed to prepare a colorimetric layer forming composition containing an electron-accepting compound.

[0385] -Preparation of the color-forming composition-

[0386] To 70 parts of the microcapsule solution (B) containing the electron-donating dye precursor obtained above (20% solution), 0.8 parts of anionic olefin resin (Arakawa Chemical Industries, Ltd., polymeron 482, 25% solids concentration, specific polymer compound), 3.1 parts of polymer (Rohm and Haas Company, OROTAN 165A, 21% solids concentration, specific polymer compound), 0.5 parts of a 15% aqueous solution of linear alkylbenzene sulfonate (DKS Co. Ltd., Neugen T), 5 parts of a 1% aqueous solution of polyoxyethylene polyoxypropylene lauroyl ether (DKS Co. Ltd., Noigen LP-70), and 5 parts of a 1% aqueous solution of sodium-bis(3,3,4,4,5,5,6,6,6-nonafluorohexyl)-2-sulfanilamide (FUJIFILM Corporation, W-AHE) were further mixed to prepare a color-forming composition.

[0387] -Preparation of materials for pressure measurement-

[0388] The color-developing layer obtained above is coated with a composition using a bar coater at a solid content of 20 g / m². 2 A color-developing layer was formed by coating a 75 μm thick polyethylene terephthalate (PET) film (A4300: manufactured by Toyobo Co., Ltd.). Then, a bar coater was used to coat the color-developing layer with a solids content of 3.5 g / m². 2 A color-developing layer is applied to form a composition, thus forming a color-developing agent layer.

[0389] Thus, a monolithic pressure measuring material was produced, which has a pressure-sensitive layer consisting of a color developer layer and a color-developing agent layer stacked sequentially on a PET film as a substrate.

[0390] (Examples 10-14)

[0391] The composition of each material was changed as shown in Table 3. Otherwise, the pressure measuring plate was made in the same manner as in Example 9.

[0392] (Comparative Example 2)

[0393] The same pressure measuring plate as the two-piece pressure measuring plate used in Comparative Example 1 above was used.

[0394] [evaluate]

[0395] The "void volume measurement" was performed on each pressure measuring plate in Examples 9 to 14.

[0396] Furthermore, the pressure measuring plates of Examples 9 to 14 and Comparative Example 2 were evaluated using the following "concentration level evaluation B" and "color development evaluation C".

[0397] [Determination of porosity]

[0398] The void volume of each pressure measuring piece in Examples 9 to 14 was measured in the same manner as that used in Examples 1 to 8.

[0399] The porosity of all pressure measuring plates obtained in Examples 9-14 was within 5 mL / m. 2 ~20mL / m 2 Within the range.

[0400] [Concentration Level Evaluation B (100MPa~500MPa)]

[0401] For the pressure measuring plates of Examples 9-14 and Comparative Example 2, the colorimetric concentration at 100 MPa and 500 MPa was measured. The difference ΔD2 between the colorimetric concentration at 500 MPa and the colorimetric concentration at 100 MPa was calculated, and the plates were evaluated according to the following evaluation criteria.

[0402] The pressure application method and measuring device are the same as those used in the above color evaluation A.

[0403] In addition, "A" and "B" represent the ranges that are permissible in practical use, with "A" being the best. The results are shown in Table 3.

[0404] <Evaluation Criteria>

[0405] “A”: △D2 is 0.4 or higher.

[0406] “B”: ΔD2 is greater than 0.1 and less than 0.4.

[0407] “C”: ΔD2 is less than 0.1.

[0408] [Hair color rating: C]

[0409] For the pressure testing plates of Examples 9-14 and Comparative Example 2, the colorimetric concentration at 300 MPa was measured. The pressurization method and measuring apparatus were the same as those described in Colorimetric Evaluation A above.

[0410] Based on the obtained measurement results, an evaluation was conducted according to the following evaluation criteria. The results are shown in Table 3.

[0411] <Evaluation Criteria>

[0412] “A”: Color concentration is 0.5 or higher.

[0413] “B”: Color concentration less than 0.5.

[0414]

[0415] In Table 3, T represents the thickness of the layer obtained by subtracting the thickness of the substrate from the thickness of the material used for pressure measurement, T / p2 represents the ratio of thickness T to the inner diameter p2 of the microcapsule, T / d2 represents the ratio of thickness T to the particle size d2 (average particle size) of the microcapsule, and Ra represents the arithmetic mean roughness of the outermost surface (pressure-sensitive layer surface) on the side opposite to the substrate. All of these values ​​were obtained by the above method.

[0416] In Table 3, "-" indicates that the corresponding component is not present or that the corresponding test item has not been performed.

[0417] Symbol Explanation

[0418] 10, 20 - Materials for pressure measurement; 12, 22 - Substrate; 14, 24 - Pressure-sensitive layer; 24a - Colorimetric layer; 24b - Colorimetric layer; 15, 25 - Electron-accepting compound; 16, 26 - Polymer matrix; 18, 28 - Microcapsule; 18a, 28a - Capsule wall; 18b, 28b - Microcapsule contents (core material).

[0419] The contents of Japanese Patent Application No. 2019-006244, filed on January 17, 2019, are incorporated herein by reference in their entirety.

[0420] All documents, patent applications and technical standards described herein are incorporated herein by reference to the same extent as those specifically and separately described herein.

Claims

1. A material for pressure measurement, comprising a substrate and a pressure-sensitive layer, The pressure-sensitive layer comprises: a polymer matrix containing polymeric compounds with a molecular weight of 1000 or higher; microcapsules containing electron-donating dye precursors and solvents; and electron-accepting compounds. The pressure-sensitive layer comprises: a color-developing layer having the electron-accepting compound and the polymer matrix; and a color-emitting layer having the microcapsules. The pressure measuring material has the substrate, the color developing layer and the color-emitting layer, and the thickness of the color-emitting layer is less than 1 / 3 of the thickness of the color developing layer.

2. The material for pressure measurement according to claim 1, wherein, The concentration difference ΔD2, which is the concentration after color development under pressure of 500 MPa minus the concentration after color development under pressure of 100 MPa, is greater than 0.

1.

3. The material for pressure measurement according to claim 1 or 2, wherein, The electron-accepting compound contains a metal salt of salicylic acid.

4. The material for pressure measurement according to claim 1 or 2, wherein, The electron-accepting compound contains acidic clay or reactive clay.

5. The material for pressure measurement according to claim 1 or 2, wherein, The pressure-sensitive layer contains inorganic particles other than the electron-accepting compound.

6. The material for pressure measurement according to claim 1 or 2, wherein the porosity is 5 mL / m 2 ~20mL / m 2 .

7. The material for pressure measurement according to claim 1 or 2, wherein, The ratio of the thickness T of the layer after subtracting the thickness of the substrate from the thickness of the material used for pressure measurement to the inner diameter p of the microcapsule, T / p, is 1.2 or higher.

8. The material for pressure measurement according to claim 1 or 2, wherein, The ratio T / p of the layer thickness T (after subtracting the thickness of the substrate from the thickness of the pressure measuring material) to the inner diameter p of the microcapsule is 1.2 to 5.

0.

9. The material for pressure measurement according to claim 1 or 2, wherein, The pressure-sensitive layer contains at least 10% by mass of the polymer compound with a molecular weight of 1000 or more relative to its total mass.

10. The material for pressure measurement according to claim 1 or 2, wherein, The substrate is a polyethylene terephthalate substrate or a polyethylene naphthalate substrate.

11. The material for pressure measurement according to claim 1 or 2, wherein, An easy-to-adhere layer is provided between the substrate and the pressure-sensitive layer.

12. The material for pressure measurement according to claim 1 or 2, wherein, The wall material of the microcapsules contains at least one selected from polyurethane urea and polyurethane.

13. A method for manufacturing a pressure measuring material, as described in any one of claims 1 to 12, comprising: A process for obtaining a color-forming composition, the color-forming composition comprising microcapsules and a solvent, wherein the microcapsules contain an electron-donating dye precursor and a solvent; A process for obtaining a colorimetric layer forming composition, wherein the colorimetric layer forming composition contains an electron-accepting compound and a polymeric compound with a molecular weight of 1000 or more; The process of forming a color-developing layer by depositing the color-developing layer on a substrate to form a color-developing layer; and The process of forming a color-developing layer by depositing the color-developing layer onto the color-developing layer and forming the color-developing layer.

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