JPWO2019003838A1 - Material for pressure measurement - Google Patents

Abstract

A microcapsule A containing an electron-donating dye precursor, and a microcapsule B containing a solvent having a melting point or a pour point of 30 ° C. or less and a polar organic compound having a melting point of more than 30 ° C. and not containing an electron-donating dye precursor. And a material for pressure measurement containing.

Description

  The present disclosure relates to materials for measuring pressure.

  The material for pressure measurement (that is, the material used for measuring pressure) is used for applications such as a bonding process of liquid crystal glass, solder printing on a printed circuit board, and pressure adjustment between rollers. As an example of the material used for measuring the pressure, for example, there is a pressure measuring film represented by Prescale (trade name; registered trademark) provided by FUJIFILM Corporation.

In recent years, materials for pressure measurement for measuring minute pressure have been studied.
For example, Japanese Patent Application Laid-Open No. 2009-19949 discloses a pressure-measuring material in which a color density difference ΔD before and after pressurization at 0.05 MPa is 0.02 or more in order to obtain a visually recognizable or readable density with a small pressure. Has been proposed.

  Japanese Patent Application Laid-Open No. 2009-63512 discloses a two-sheet type pressure measuring material capable of obtaining good color development at a low pressure, such as a number average wall thickness σ in a microcapsule and a surface roughness Ra of a color developer layer. Attention has been paid to a pressure-measuring material in which coloring due to rubbing is suppressed.

As described in JP-A-2009-19949 and JP-A-2009-63512 described above, materials for pressure measurement for measuring minute pressure have been studied.
However, in recent years, the necessity of more precisely grasping a region to which a minute pressure is applied has been increasing due to the progress of higher functionality and higher definition of products.
For example, in the field of liquid crystal panels, as a bonding method, a vacuum bonding method may be adopted in response to an increase in area. In this case, a pressure of less than 0.1 MPa (ie, atmospheric pressure) is applied. It is necessary to precisely grasp the added area.
Further, in the field of smartphones, as the modules become thinner, bonding with a minute pressure of 0.05 MPa or less is required from the viewpoint of improving the yield at the time of bonding. For this reason, in the field of smart phones, it is necessary to precisely grasp the area where a small pressure of 0.05 MPa or less is applied.

  Under the circumstances described above, the measurable pressure range of a commercially available pressure measurement film, that is, the range of pressure at which color is obtained by pressurization is 0.05 MPa or more. For this reason, when a weak pressure of less than 0.05 MPa is applied to a commercially available pressure measurement film, the color required for detection is insufficient, or even if a color is obtained, the pressure difference is reduced. It is difficult to obtain the density gradation necessary for the determination.

In the prior art, for example, a material having improved color density difference ΔD before and after pressurization at 0.05 MPa, such as a pressure measuring material described in JP-A-2009-19949, has been proposed. However, even when a small pressure of less than 0.05 MPa is applied, if the sensitivity is increased so as to obtain a density and a density gradation that can be visually recognized or read, color formation due to rubbing or the like during handling is likely to occur. There is a problem.
Therefore, even in the pressure range of 0.05 MPa or less, a good color is formed, a color corresponding to a minute pressure difference (that is, a density gradation) is obtained, and unnecessary color formation due to rubbing or the like can be suppressed. The establishment of technology is desired.

  An object of one embodiment of the present invention is to provide a pressure measuring material which is excellent in gradation of color development at a very small pressure of 0.05 MPa or less and in which color development due to rubbing is suppressed.

Specific means for solving the above problems include the following aspects.
<1> a microcapsule A containing an electron-donating dye precursor,
A microcapsule B containing a solvent having a melting point or a pour point of 30 ° C. or less and a polar organic compound having a melting point of more than 30 ° C., and not containing an electron-donating dye precursor,
Material for pressure measurement including.
<2> The pressure measuring material according to <1>, wherein the polar organic compound having a melting point of more than 30 ° C is a compound having an alkyl group having 12 or more carbon atoms and an amide bond.
<3> The polar organic compound having a melting point of more than 30 ° C. is at least one selected from the group consisting of salicylic acid compounds, salicylic acid compound salts, phenol compounds and sulfonamide compounds. Material for pressure measurement.
<4> The pressure measurement material according to any one of <1> to <3>, wherein the volume standard median diameter D50B of the microcapsule B is larger than the volume standard median diameter D50A of the microcapsule A.
<5> A first material in which a color former layer containing microcapsules A is disposed on a first substrate, and a color developer layer containing an electron-accepting compound is disposed on a second substrate. A second material;
With
The material for pressure measurement according to any one of <1> to <4>, wherein at least one of the first material and the second material contains microcapsules B.
<6> Over the color former layer of the first material, a color developer layer of the second material having the same area as the color former layer of the first material is put in contact with the color former layer of the first material, and <5> The pressure measurement material according to <5>, wherein the density difference obtained by subtracting the density before rubbing from the color development density after rubbing the material by repeating the first material 20 times is less than 0.02.
<7> The difference in density obtained by subtracting the density after applying pressure at 0.04 MPa to form a color after applying pressure at 0.05 MPa to form a color is 0.20 or more. The material for pressure measurement according to any one of <6>.

  According to one embodiment of the present invention, there is provided a pressure measurement material which is excellent in gradation of color development at a very small pressure of 0.05 MPa or less and in which color development due to rubbing is suppressed.

Hereinafter, the pressure measurement material of the present disclosure will be described in detail.
In the present disclosure, a numerical range represented by using “to” means a range including numerical values described before and after “to” as a lower limit and an upper limit.
In the numerical ranges described stepwise in the present disclosure, an upper limit or a lower limit described in a certain numerical range may be replaced with an upper limit or a lower limit of another numerical range described in a stepwise manner. Further, in the numerical ranges described in the present disclosure, the upper limit or the lower limit described in a certain numerical range may be replaced with the value shown in the embodiment.
In the present disclosure, the amount of each component in the composition, when there are a plurality of substances corresponding to each component in the composition, unless otherwise specified, means the total amount of the plurality of substances present in the composition I do.
In the present disclosure, a combination of two or more preferred embodiments is a more preferred embodiment.

<Material for pressure measurement>
The pressure measurement material of the present disclosure includes a microcapsule A containing an electron-donating dye precursor, a solvent having a melting point or a pour point of 30 ° C. or lower (hereinafter, abbreviated as “specific solvent” as appropriate), and a melting point or a flow. A microcapsule B containing a polar organic compound having a point of more than 30 ° C. (hereinafter abbreviated as “specific polar organic compound” as appropriate) and containing no electron-donating dye precursor.

The electron-donating dye precursor contained in the microcapsule A is colored by contacting the electron-donating dye precursor with an electron-accepting compound which is a developer for developing the color of the electron-donating dye precursor.
As the specific polar organic compound contained in the microcapsule B, in the measurement of pressure or pressure distribution using a color development reaction between an electron-donating dye precursor and a color developer, sensitivity, measurement performance such as color development can be improved. The compound can be selected.

  As a material used for measuring pressure, conventionally proposed and widely used, all such materials are suitable for detecting a pressure in a range of 0.05 MPa or more applied at the time of pressurization. It is used for. On the other hand, in recent years, as the functionality and definition of products have become higher, the required pressure detectability has fallen below 0.05 MPa. Conventionally, pressure measurement materials and the like described in JP-A-2009-19949 and JP-A-2009-63512 have been provided, but the pressure range suitable for detection deviates from the pressure range required in recent years. In some cases.

  On the other hand, it is difficult to design a pressure-measuring material so that a good color is obtained with a minute pressure and a density gradation appears in a wide pressure range. For example, if the sensitivity is increased to detect with a very small pressure, the color is excessively developed with a very small pressure, and as a result, the pressure range in which the density gradation appears is likely to be narrowed. Unexpected colors are likely to be mixed.

  In view of the above, in the pressure measurement material of the present disclosure, a microcapsule A containing an electron-donating dye precursor, a solvent (specific solvent) having a melting point or pour point of 30 ° C. or less, and a polar organic material having a melting point of more than 30 ° C. A compound (specific polar organic compound) is included therein, and microcapsules B not including an electron-donating dye precursor are mixed.

Thereby, the pressure-measuring material of the present disclosure can achieve a color development balance with respect to a minute pressure, has excellent color gradation even at a minute pressure of 0.05 MPa or less, and exhibits color due to rubbing. A suppressed material for pressure measurement can be provided.
Here, the “color tone gradation” means a property that the color density increases with an increase in applied pressure. Particularly preferred gradation of color development is a property in which, in a pressure range of 0.06 MPa or less, the color density increases linearly with an increase in pressure (that is, the pressure and the color density are proportional).

  Specifically, when pressure is applied to the pressure measuring material of the present disclosure, the microcapsules A are broken, whereby the electron-donating dye precursor comes into contact with the electron-accepting compound (that is, the developer), A coloring area is formed. If the applied pressure is not uniform in the applied area, the color is developed at a density corresponding to the pressure, and a colored area having a density gradation is formed.

  The mixture of the microcapsules A and B in the pressure measurement material of the present disclosure suppresses the destruction of the microcapsules A by breaking the microcapsules B when an unexpected small pressure is applied. Unnecessary coloring can be suppressed. That is, the microcapsule B has a function of suppressing the destruction of the microcapsule A by breaking the microcapsule B itself (that is, a function as a dummy capsule).

  The specific solvent contained in the microcapsules B can improve the reactivity between the electron-donating dye precursor and the developer when the microcapsules A are broken. Further, as the specific polar organic compound contained in the microcapsule B, in the measurement of pressure or pressure distribution using a color-forming reaction between an electron-donating dye precursor and a developer, measurement performance such as sensitivity and color-forming property is improved. Can be selected. Therefore, the measurement performance of the material for pressure measurement is further improved by the inclusion of the microcapsules B.

  Thereby, the pressure measurement material of the present disclosure has excellent color developability at a minute pressure while suppressing unnecessary coloring at a minute pressure due to rubbing and the like, and has a density gradation corresponding to a wide pressure range. Can be reproduced.

[Microcapsule A]
The microcapsule A is a microcapsule containing an electron-donating dye precursor as a coloring component. The microcapsule A preferably contains a solvent, and if necessary, may further contain other components such as auxiliary solvents and additives.

-Electron donating dye precursor-
The electron-donating dye precursor is not particularly limited and is colorless as long as it has a property of coloring by donating an electron or accepting a proton (hydrogen ion; H ⁺ ) such as an acid. Is preferred.
In particular, the electron-donating dye precursor has a partial skeleton such as lactone, lactam, sultone, spiropyran, ester, and amide, and when contacted with an electron-accepting compound described later, these partial skeletons are opened or Colorless compounds that cleave are preferred.

As the electron-donating dye precursor, those known for use in pressure-sensitive copying paper or heat-sensitive recording paper can be used. For example, triphenylmethane phthalide compound, fluoran compound, phenothiazine compound, indolyl phthalide compound, leuco auramine compound, rhodamine lactam compound, triphenyl methane compound, diphenyl methane compound, triazene compound, Various compounds such as spiropyran compounds and fluorene compounds are exemplified.
The details of the above compounds can be referred to the description in JP-A-5-257272.
The electron donating dye precursor may be used alone or in combination of two or more.

The electron-donating dye precursor enhances the color developability in a minute pressure range of 0.05 MPa or less, and from a viewpoint of expressing a high concentration at a minute pressure, that is, a concentration change (concentration gradient) corresponding to a wide pressure range, Those having a high molar extinction coefficient (ε) are preferred. The molar extinction coefficient (ε) of the electron-donating dye precursor is preferably at least 10,000 mol ⁻¹ · cm ⁻¹ · L, more preferably at least 15,000 mol ⁻¹ · cm ⁻¹ · L, and furthermore Is preferably at least 25000 mol ⁻¹ · cm ⁻¹ · L.

  Preferable examples of the electron donating dye precursor having ε in the above range include 3- (4-diethylamino-2-ethoxyphenyl) -3- (1-ethyl-2-methylindol-3-yl) -4. -Azaphthalide (ε = 61000), 3- (4-diethylamino-2-ethoxyphenyl) -3- (1-n-octyl-2-methylindol-3-yl) phthalide (ε = 40000), 3- [2 , 2-Bis (1-ethyl-2-methylindol-3-yl) vinyl] -3- (4-diethylaminophenyl) -phthalide (ε = 40000), 9- [ethyl (3-methylbutyl) amino] spiro [ 12H-benzo [a] xanthen-12,1 ′ (3′H) isobenzofuran] -3′-one (ε = 34000), 2-anilino-6-dibutylamino-3-methylfur Oran (ε = 22000), 6-diethylamino-3-methyl-2- (2,6-xyridino) -fluoran (ε = 19000), 2- (2-chloroanilino) -6-dibutylaminofluoran (ε = 21000) ), 3,3-bis (4-dimethylaminophenyl) -6-dimethylaminophthalide (ε = 16000), 2-anilino-6-diethylamino-3-methylfluoran (ε = 16000) and the like.

When one kind of electron-donating dye precursor having a molar extinction coefficient ε in the above range is used alone, or two or more kinds containing an electron-donating dye precursor having a molar extinction coefficient ε in the above range are mixed. When used, the proportion of the electron-donating dye precursor having a molar extinction coefficient (ε) of 10,000 mol ⁻¹ · cm ⁻¹ · L or more in the total amount of the electron-donating dye precursor is less than 0.05 MPa. From the viewpoint of improving color development in a minute pressure range and expressing a concentration change (concentration gradient) over a wide pressure range, the range of 10% by mass to 100% by mass is preferable, and the range of 20% by mass to 100% by mass is more preferable. More preferably, the range is 30% by mass to 100% by mass.
When two or more kinds of electron-donating dye precursors are used, it is preferable to use two or more kinds each having an ε of 10,000 mol ⁻¹ · cm ⁻¹ · L or more.

The molar extinction coefficient (ε) can be calculated from the absorbance when the electron-donating dye precursor is dissolved in a 95% aqueous acetic acid solution. Specifically, in a 95% acetic acid aqueous solution of an electron-donating dye precursor whose concentration is adjusted so that the absorbance becomes 1.0 or less, the length of the measuring cell is set to Acm, and the concentration of the electron-donating dye is set to B mol. / L and absorbance C, can be calculated by the following equation.
Molar extinction coefficient (ε) = C / (A × B)

-Solvent-
The microcapsule A preferably contains at least one kind of solvent.
As the solvent, a known solvent for use in pressure-sensitive copying paper or heat-sensitive recording paper can be used.
As the solvent, specifically, for example, an alkylnaphthalene-based compound such as diisopropylnaphthalene, a diarylalkane-based compound such as 1-phenyl-1-xylylethane, an alkylbiphenyl-based compound such as isopropylbiphenyl, a triarylmethane-based compound, an alkylbenzene-based compound Aromatic hydrocarbons such as compounds, benzylnaphthalene compounds, diarylalkylene compounds and arylindane compounds; aliphatic hydrocarbons such as isoparaffin; soybean oil, corn oil, cottonseed oil, rapeseed oil, olive oil, coconut oil, castor oil, fish oil, etc. And high-boiling fractions of natural products such as mineral oil.

The solvents may be used alone or in combination of two or more.
The mass ratio (solvent: precursor) of the solvent and the electron-donating dye precursor contained in the microcapsule A is preferably in the range of 98: 2 to 30:70, and 97: 3 from the viewpoint of coloring. The range of ４０40: 60 is more preferred, and the range of 95: 5 to 50:50 is even more preferred.

-Auxiliary solvent-
The microcapsule A may include an auxiliary solvent as necessary.
Examples of the auxiliary solvent include solvents having a boiling point of 130 ° C. or lower.
More specifically, examples of the auxiliary solvent include ketone compounds such as methyl ethyl ketone, ester compounds such as ethyl acetate, and alcohol compounds such as isopropyl alcohol.

-Other components-
The microcapsule A may include other components other than the above, if necessary.
Other components include additives such as an ultraviolet absorber, a light stabilizer, an antioxidant, a wax, and an odor suppressant.

-Volume-based median diameter of microcapsule A (D50A)-
The volume-based median diameter of the microcapsules A (hereinafter, also referred to as “D50A”) is not particularly limited, but is preferably more than 10 μm and less than 40 μm.
When D50A is less than 40 μm, the coloring property does not become too high, so that coloring due to rubbing or the like can be further suppressed.
When D50A is more than 10 μm, unevenness on the surface of the layer containing microcapsules A (for example, coating unevenness in a mode in which a color forming agent layer containing microcapsules A is applied and formed) can be further suppressed.
D50A is preferably from 20 μm to 35 μm, more preferably from 25 μm to 35 μm.

  In the present disclosure, “the median diameter of the volume standard of the microcapsule” refers to the particle on the large diameter side and the particle diameter on the small diameter side when the entire microcapsule is divided into two thresholds with the particle diameter at which the cumulative volume becomes 50%. Refers to a diameter whose total volume is equal.

The median diameter of the volume standard of the microcapsule in the microcapsule of the present disclosure is specifically measured by the following method.
First, a dispersion of microcapsules is obtained. The obtained dispersion is coated on an arbitrary support and dried to form a coating film. The surface of the obtained coating film is photographed with an optical microscope at a magnification of 150 times, and the size of all the microcapsules in a range of 2 cm × 2 cm is measured and calculated.

-Number average wall thickness of microcapsule A-
The number average wall thickness of the microcapsule A depends on various conditions such as the material of the capsule wall and D50A, but from the viewpoint of color development in a minute pressure range of 0.05 MPa or less, from 0.01 μm to 0.15 μm. Is preferably, and more preferably 0.02 μm to 0.10 μm.

In the present disclosure, the wall thickness of the microcapsule refers to the thickness (μm) of the capsule wall of the microcapsule (for example, a resin film forming the microcapsule). The concept of microcapsules here includes both microcapsules A and microcapsules B described later.
The number average wall thickness of the microcapsules is obtained by measuring the thickness (μm) of each capsule wall of five microcapsules by a scanning electron microscope (SEM), and measuring the obtained capsule wall thickness (5 microcapsules). (Measured value) is a number average (that is, a simple average).
Specifically, first, the microcapsule-containing liquid is applied on an arbitrary substrate (for example, a first substrate) and dried to form a coating film. A cross section of the obtained coating film is prepared, and the cross section is observed using an SEM. Any five microcapsules are selected from the obtained SEM image. The cross section of the selected five microcapsules is observed, and the thickness of the capsule wall in each of the five microcapsules is determined. The measured values (5 measured values) of the capsule wall thickness are number averaged, and the obtained number average value is defined as the number average wall thickness of the microcapsules.

The ratio of the number average wall thickness of the microcapsule A to the D50A of the microcapsule A (that is, the number average wall thickness / D50A ratio) is 1.0 from the viewpoint of color development in a minute pressure range of 0.05 MPa or less. × 10 ^{−3 to} 4.0 × 10 ⁻³ is preferable, and 1.3 × 10 ^{−3 to} 2.5 × 10 ⁻³ is more preferable.

[Microcapsule B]
The microcapsule B contains a solvent having a melting point or pour point of 30 ° C. or less (a specific solvent) and a polar organic compound having a melting point of more than 30 ° C. (a specific polar organic compound), and contains an electron-donating dye precursor as a coloring component. It is a microcapsule not included. The microcapsule B may further include an auxiliary solvent, an additive, and the like, if necessary.

  The microcapsule B has a function as a dummy capsule that suppresses the destruction of the microcapsule A, and uses a specific polar organic compound and a specific solvent that are released outside the capsule when the microcapsule B is destroyed. The measurement performance of the material for pressure measurement is further improved.

-Solvent having a melting point or pour point of 30 ° C or less-
The microcapsule B contains a solvent (specific solvent) having a melting point or a pour point of 30 ° C. or less.
The specific solvent contained in the microcapsule B may be only one type, or may be two or more types. The specific solvent can function as an oil component.

The specific solvent contained in the microcapsule B is not particularly limited as long as it can be applied as an oil component contained in the microcapsule B and has a melting point or a pour point of 30 ° C. or less. The specific solvent is a solvent that can dissolve or disperse the specific polar organic compound.
When the melting point or the pour point of the specific solvent is 30 ° C. or lower, when the pressure measurement material of the present disclosure is used, for example, room temperature, which is the most versatile measurement environment (specifically, the recommended measurement environment), When the microcapsule B is used in a temperature environment around 25 ° C.), the inclusions of the microcapsules B in the material for pressure measurement have a fluidity.

Whether the melting point or the pour point of the specific solvent is 30 ° C. or lower can be determined based on whether or not the inclusions of the microcapsules are visually fluid at 30 ° C. The state in which the inclusions of the microcapsules show fluidity is an indicator that the melting point or pour point of the specific solvent is 30 ° C. or less.
When performing more detailed measurement, it can be confirmed by, for example, a test method described in JIS K2269 (1987).
When two or more specific solvents are contained, the melting point or pour point of the specific solvent may be confirmed by visually checking whether or not the two or more types are in a liquid state at 30 ° C.
When the specific solvent is a commercially available product on the market, the literature value can be used as the melting point or pour point when there is a literature value such as a catalog value.

Specific examples of the specific solvent contained in the microcapsule B include compounds having a melting point or a pour point of 30 ° C. or lower among the above-mentioned compounds that can be contained in the microcapsule A. From the viewpoints of color development and dissolution or dispersibility of the specific polar organic compound, diarylalkane compounds such as 1-phenyl-1-xylylethane (melting point: ≤-50 ° C.), aliphatic hydrocarbons such as isoparaffin, and the like are preferable. .
Commercial products can be used as the specific solvent. Examples of the specific solvent which is a commercially available product include IP Solvent 1620 (synthetic isoparaffin, Idemitsu Kosan Co., Ltd., pour point: <-70 ° C.) and IP Solvent 2835 (synthetic isoparaffin, Idemitsu Kosan Co., Ltd., pour point: < -70 ° C), Hysol (registered trademark) SAS296 (mixture of 1-phenyl-1-xylylethane and 1-phenyl-1-ethylphenylethane, pour point: -47.5 ° C, Nippon Oil Co., Ltd.), etc. Is mentioned.

  The mass ratio (specific solvent: specific polar organic compound) of the specific solvent and the specific polar organic compound described later included in the microcapsule B is different from that of the microcapsule B in view of the expected effect of the specific polar organic compound. There is no particular limitation as long as the inside has fluidity. For example, when the solubility of the specific solvent in the specific polar organic compound is high, the ratio of the specific solvent to the mass ratio of the specific solvent to the specific polar organic compound can be reduced. This mass ratio may be set mainly in consideration of the balance between the solubility of the specific solvent in the specific polar organic compound and the viscosity of the specific solvent in which the specific polar organic compound is dissolved.

-Polar organic compound having a melting point of more than 30 ° C-
The microcapsule B contains a polar organic compound (specific polar organic compound) having a melting point of more than 30 ° C.
The specific polar organic compound contained in the microcapsule B may be only one kind or two or more kinds.
In the microcapsule B, the content of the specific polar organic compound is not particularly limited as long as the inside of the microcapsule B has fluidity. About the mass ratio of the specific solvent and the specific polar organic compound, the solubility of the specific solvent in the specific polar organic compound mainly, if the specific solvent is appropriately set in consideration of the balance of the viscosity of the dissolved state of the specific polar organic compound. Good.

  The specific polar organic compound encapsulated in the microcapsule B is an organic compound having a melting point of more than 30 ° C. and having polarity, and a pressure or pressure using a color-forming reaction between an electron-donating dye precursor and a developer. In the measurement of the distribution, a compound that contributes to the improvement of the measurement performance such as sensitivity and color development can be selected.

  The melting point of the specific polar organic compound can be confirmed by a general method (capillary method) as a visual melting point measuring method. Specifically, it can be confirmed by the melting point measuring method described in JIS K6220-1 (2015).

In the present disclosure, a polar organic compound means a compound having at least one atom selected from an oxygen atom, a nitrogen atom, and a sulfur atom.
In the specific polar organic compound, specific examples of the partial structure having at least one atom selected from an oxygen atom, a nitrogen atom, and a sulfur atom include, for example, an amide bond, a urethane bond, a urea bond, and an ether bond. , An ester bond, a sulfonyl bond, a sulfonamide group, an amino group, a hydroxy group, a carboxy group, a sulfo group and the like. One of these partial structures may be contained in the molecular structure of the polar organic compound, or two or more thereof may be contained.

  As the specific polar organic compound, a compound that promotes a color-forming reaction between an electron-donating dye precursor and a developer that forms a color of the electron-donating dye precursor (that is, a sensitizer), or an electron-donating dye precursor Is preferably a compound having a color-developing ability (namely, a color developer).

  When the microcapsule B contains a developer, the pressure measurement material of the present disclosure combines both the developer not contained in the microcapsule and the microcapsule B containing the developer. Is preferred. It is preferable to use the microcapsules B containing the color developer together with the color developer not included in the microcapsules, because the effect of improving the color developing ability can be obtained and the undesired coloring can be suppressed.

  Specific organic compounds that can function as sensitizers include polar organic compounds known as sensitizers that can promote the reaction between an electron-donating dye precursor and an electron-donating dye precursor, and have a melting point of more than 30 ° C. The compound of. Such a specific organic compound may be selected from compounds used as sensitizers in pressure-sensitive copying paper or heat-sensitive recording paper. As the specific organic compound that can function as a sensitizer, a commercially available product may be used.

  Specific examples of the specific organic compound that can function as a sensitizer include a compound having an amide bond, a compound having a sulfonamide group, a compound having a urea bond, and a compound having a urethane bond.

Among these, as the specific organic compound that can function as a sensitizer, a compound having an amide bond is preferable, and a compound having an aliphatic group and an amide bond (hereinafter, also referred to as fatty acid amide) is more preferable. And a compound having an alkyl group and an amide bond (hereinafter, also referred to as a saturated fatty acid amide).
From the viewpoint of diffusibility and compatibility, a compound having an alkyl group having 12 or more carbon atoms and an amide bond is particularly preferable. Examples of the compound having an alkyl group having 12 or more carbon atoms and an amide bond include the examples described later as specific examples of the saturated fatty acid amide, and among these, stearic acid amide is particularly preferable.

Examples of the specific organic compound that can function as a sensitizer include fatty acid amides described in JP-A-5-10485 (specifically, long-chain fatty acid amides having a total carbon number of 16 or more, N -Alkyl-substituted long-chain fatty acid amides, and compounds having a molecular weight of 250 or more selected from N, N-dialkyl-substituted long-chain fatty acid amides having a total carbon number of 26 or more).
Other examples of the specific organic compound capable of functioning as a sensitizer include compounds described in paragraph 0031 of JP-A-06-210948, compounds described in paragraph 0045 of WO2013 / 141224A1, and The compounds described in paragraph 0063 of WO 2013/065704 A1 are exemplified.

  Specific examples of the specific organic compound capable of functioning as a sensitizer include the compounds described above, specifically, the following compounds, but are not limited thereto. The melting points of the compounds exemplified below are all higher than 30 ° C.

  Saturated fatty acid amides (eg, lauric acid amide, palmitic acid amide, stearic acid amide, behenic acid amide, hydroxystearic acid amide, etc.), unsaturated fatty acid amides (eg, oleic acid amide, erucic acid amide, etc.), N-substituted fatty acids Amides (for example, N-oleylpartimidate, N-stearylstearic acid amide, N-stearyloleic acid amide, N-oleylstearic acid amide, N-stearylerucamide, etc.), methylolamide (for example, methylolstearic acid amide) Etc.), saturated fatty acid bisamides (for example, methylenebisstearic acid amide, ethylenebiscapric acid amide, ethylenebislauric acid amide, ethylenebisstearic acid amide, ethylenebishydroxystearic acid amide, ethylenebisbehate) Acid amide, hexamethylenebisstearic acid amide, hexamethylenebisbehenic acid amide, hexamethylenehydroxystearic acid amide, N, N'-distearyladipamide, N, N'-distearyladipamide, N, N ' -Distearyl sebacamide, etc.), unsaturated fatty acid bisamides (eg, ethylene bisoleic acid amide, ethylene bis erucic acid amide, hexamethylene bis oleic acid amide, N, N'-dioleyl adipamide, N, N ' -Dioleyl sebacamide, etc.), aromatic bisamides (eg, m-xylylene bisstearic acid amide, m-xylylene bishydroxystearic acid amide, N, N'-cystearyl isophthalic acid amide, etc.), fatty acid esters Amides (eg, stearoamidoethyl Stearate, etc.),

  β-naphthyl benzyl ether, N-stearyl urea, N, N′-distearyl urea, β-naphthoic acid phenyl ester, 1-hydroxy-2-naphthoic acid phenyl ester, 2- (p-methylbenzyloxy) naphthalene, -Benzyloxynaphthalene, 1,4-dimethoxynaphthalene, 1-methoxy-4-benzyloxynaphthalene, N-stearoylurea, 1,2-bis (3-methylphenoxy) ethane, 1,2-diphenoxyethane, 1- Phenoxy-2- (4-chlorophenoxy) ethane, 1,2-diphenoxymethylbenzene, 1,4-butanediol phenyl ether, dibenzyl terephthalate, dimethyl terephthalate, dibenzyl oxalate, dibenzyl oxalate Chlorobenzyl) ester, oxalic acid di (4-meth Benzyl) ester, methyl 4-hydroxybenzoate, benzyl 4-hydroxybenzoate, (4′-chlorobenzyl) 4-hydroxybenzoate, ethyl 1,2-bis (4′-hydroxybenzoate), 1,5- Bis (4′-hydroxybenzoic acid) pentyl, 1,6-bis (4′-hydroxybenzoic acid) hexyl, 4,4′-dimethoxybenzophenone, 4,4′-dichlorobenzophenone, 4,4′-difluorobenzophenone, Diphenylsulfone, 4,4'-dichlorodiphenylsulfone, 4,4'-difluorodiphenylsulfone, 4,4'-dichlorodiphenyldisulfide, diphenylamine, 2-methyl-4-methoxydiphenylamine, N, N'-diphenyl-p -Phenylenediamine, 1- (N-phenylamino) naphthalene, 1,3 Diphenyl-1,3-propanedione, N-stearyl-N '-(2-hydroxyphenyl) urea, N-stearyl-N'-(3-hydroxyphenyl) urea, N-stearyl-N '-(4-hydroxy And phenyl) urea.

  Examples of the specific organic compound that can function as a color developer include an electron-accepting compound having a melting point of more than 30 ° C., among electron-accepting compounds known as color developing agents that form an electron-donating dye precursor. Such an electron accepting compound may be selected from compounds used in pressure-sensitive copying paper or thermosensitive recording paper. As the specific organic compound that can function as a developer, a commercially available product may be used.

Among these, from the viewpoint of reactivity and diffusibility, the specific organic compound that can function as a developer is selected from the group consisting of salicylic acid compounds, salts of salicylic acid compounds, phenol compounds, and sulfonamide compounds. At least one is preferred.
The salicylic acid-based compound means a compound having a partial structure derived from salicylic acid in the molecular structure. The phenolic compound means a compound having a partial structure derived from phenol in the molecular structure. The sulfonamide compound means a compound having a sulfonamide group in the molecular structure.
Specific examples of the specific organic compound capable of functioning as a color developer in the pressure measurement material of the present disclosure will be described later.

  From the viewpoint of reactivity, a salt of a salicylic acid-based compound or a phenolic compound is more preferable. As a salt of the salicylic acid-based compound, a metal salt of a 3,5-disubstituted salicylic acid derivative is preferable, and a 3,5-diaaralkyl-substituted salicylic acid derivative is used. (Zinc salt, nickel salt, aluminum salt, calcium salt, etc.) are more preferable, and zinc 3,5-di-α-methylbenzylsalicylate is particularly preferable. As the phenolic compound, 2,4′-dihydroxydiphenylsulfone or 4,4′-dihydroxydiphenylsulfone is particularly preferred.

  Examples of the specific organic compound capable of functioning as a developer include the compounds described above, specifically, among the compounds described in the following documents, an electron accepting compound capable of functioning as a developer Are preferred. The melting points of the compounds exemplified below are all higher than 30 ° C.

  Examples of the specific organic compound capable of functioning as a developer include a compound described in paragraph No. 0046 of JP-A-2009-63512, a compound described in paragraph No. 0015 described in JP-A-6-183141, and a compound described in JP-A-6-183141. Compounds described in paragraph No. 0008 of JP-A-5-104850, compounds described in WO 2013/141224, compounds described in paragraphs 0032 to 0038 described in WO 2011/108411, J. Am. Jpn. Soc. Color Mater. , 88 [11], 378-382 (2015).

Examples of the specific organic compound that can function as a color developer include the following compounds.
3,5-di-t-butylsalicylic acid, 3,5-di-t-octylsalicylic acid, 3,5-di-t-nonylsalicylic acid, 3,5-di-t-dodecylsalicylic acid, 3-methyl-5 t-dodecylsalicylic acid, 3-t-dodecylsalicylic acid, 5-t-dodecylsalicylic acid, 5-cyclohexylsalicylic acid, 3,5-bis (α, α-dimethylbenzyl) salicylic acid, 3-methyl-5- (α-methylbenzyl) ) Salicylic acid, 3- (α, α-dimethylbenzyl) -5-methylsalicylic acid, 3- (α, α-dimethylbenzyl) -6-methylsalicylic acid, 3- (α-methylbenzyl) -5- (α, α -Dimethylbenzyl) salicylic acid, 3- (α, α-dimethylbenzyl) -6-ethylsalicylic acid, 3-phenyl-5- (α, α-dimethylbenzyl) salicylic acid, 3,5-di Benzyl salicylic acid, 3,5-di-α, α-dimethylbenzyl salicylic acid, 3,5-bis (α-methyl-α-tolylmethyl) salicylic acid, 3,5-bis (-α-methylbenzyl) salicylic acid, 3-α -Benzylated phenylethylsalicylic acid, 3-α-methyl-α-ethylpentyl-5-α, α-dimethylbenzylsalicylic acid, 3-cumyl-5-t-octylsalicylic acid, 3-cumyl-5-t-butylsalicylic acid , 3-t-butyl-5-cumylsalicylic acid, 3,5-di-t-butylsalicylic acid, 3,5-di-t-octylsalicylic acid, 3,5-di-t-nonylsalicylic acid, 3,5- Bis (methylcumyl) salicylic acid, 3,5-biscumylsalicylic acid, 3-α-methylbenzyl-6-methylsalicylic acid, 3-α-benzylated phenylethyl-6-methylsa Tolic acid, 3-α-methyl-α-ethylpentyl-6-methylsalicylic acid, 3,5-bis (-α-benzylated phenylethyl) salicylic acid, 3,5-bis (benzylated benzyl) salicylic acid, 3,5- Bis (α-methylbenzyl) -6-methylsalicylic acid, 3-α-tolylethyl-6-methylsalicylic acid, 3,5-bis (α, α-dimethylbenzyl) -6-methylsalicylic acid, 3,5-di-t -Octyl-6-methylsalicylic acid, 3-α-dimethylphenylethyl-6-methylsalicylic acid, 3-α-ethylphenylethyl-6-methylsalicylic acid, 3-α-isopropylphenylethyl-6-methylsalicylic acid, 3-α-benzylated benzylphenylethyl-6-methylsalicylic acid, 3-α-methyl-α-ethylpentyl-6-ethylsalicylic acid, 3- Nonyl-6-methylsalicylic acid, 3-dodecyl-6-methylsalicylic acid, methyl salicylate, ethyl salicylate, isoamyl salicylate, isopentyl salicylate, phenyl salicylate, benzyl salicylate, 4-n-octyloxysalicylic acid, 4-n-butyloxysalicylic acid, 4-n-pentyloxysalicylic acid, 3-n-dodecyloxysalicylic acid, 3-n-octoctanoyloxysalicylic acid, 4-n-octyloxycarbonylaminosalicylic acid, 4-n-octanoyloxycarbonylaminosalicylic acid, carboxy-modified terpene Phenol resins, compounds such as salicylic acid resins, which are reaction products of 3,5-bis (α-methylbenzyl) salicylic acid and benzyl chloride, or metal salts thereof (for example, zinc salts, nickel salts, aluminum salts) Umushio, calcium salt),

2,4'-dihydroxydiphenylsulfone, 4,4'-dihydroxydiphenylsulfone, 2,2-bis (4-hydroxyphenyl) propane, 2,2-bis (hydroxyphenyl) butane, 2,2-bis (hydroxyphenyl ) Pentane, 2,2-bis (hydroxyphenyl) heptane, 1,1-bis (4-hydroxyphenyl) cyclohexane, butyl bis (4-hydroxyphenyl) acetate, benzyl bis (4-hydroxyphenyl) acetate, bis (3 -Methyl-4-hydroxyphenyl) sulfone, 4-hydroxyphenyl-4'-methylphenylsulfone, 3-chloro-4-hydroxyphenyl-4'-methylphenylsulfone, 3,4-dihydroxyphenyl-4'-methylphenyl Sulfone, 4-isopropylphenyl-4'-hydroxy Phenylsulfone, 4-hydroxy-4'-n-propoxydiphenylsulfone, 4-hydroxy-4'-isopropoxydiphenylsulfone, 4-hydroxy-4'-allyloxydiphenylsulfone, bis (3-allyl-4-hydroxyphenyl ) Sulfone, 4-hydroxyphenyl-4′-benzyloxyphenylsulfone, 4-isopropylphenyl-4′-hydroxyphenylsulfone, bis (2-methyl-3-t-butyl-4-hydroxyphenyl) sulfide, 4-hydroxy Methyl benzoate, p-hydroxybenzoic acid benzyl ester, oligomer of hydroxybenzoic acid ester, 4-hydroxybenzoic acid (4'-chlorobenzyl), 1,2-bis (4'-hydroxybenzoic acid) ethyl, 1,5 -Bis (4'-hydroxybenzoic acid) Methyl, 1,6-bis (4′-hydroxybenzoic acid) hexyl, dimethyl 3-hydroxyphthalate, stearyl gallate, lauryl gallate or a metal salt thereof, salicylamide, salicylanilide, 4,4′-butylidenebis (6 -T-butyl-3-methylphenol), 4,4'-bis (p-toluenesulfonylaminocarbonylamino) diphenylmethane, 4,4'-bis (o-toluenesulfonylaminocarbonylamino) diphenylmethane, 4,4'- Bis (p-toluenesulfonylaminocarbonylamino) diphenyl sulfide, 4,4'-bis (p-toluenesulfonylaminocarbonylamino) diphenyl ether, Np-toluenesulfonyl-N'-3- (p-toluenesulfonyloxy) phenyl Urea, N- (p-toluenes Ruphonyl) -N '-(p-butoxycarbonyl) urea, N- (p-toluenesulfonyl) -N'-phenylurea, sulfonylurea derivative, N- (4-hydroxyphenyl) -4-toluenesulfonamide, N- (2-hydroxyphenyl) -4-toluenesulfonamide, N-phenyl-4-hydroxybenzenesulfonamide and the like.

-Volume-based median diameter of microcapsule B (D50B)-
The volume-based median diameter of the microcapsules B (hereinafter, also referred to as “D50B”) is preferably set according to the purpose, such as an increase in color density or suppression of color development due to rubbing.
For example, the pressure measurement material of the present disclosure can be used for high pressure measurement without having to consider color development suppression due to rubbing, and in this case, the volume-based median diameter D50B of the microcapsule B is The smaller the value, the higher the color density in the high pressure portion and the higher the gradation.
On the other hand, in the measurement of the minute pressure of 0.05 MPa or less, the volume standard median diameter D50B of the microcapsule B is larger than the volume standard median diameter D50A of the microcapsule A from the viewpoint of suppressing color development due to rubbing. Larger is preferred. Thereby, the effect of suppressing color formation due to rubbing by the microcapsules B is more effectively exhibited.

  The D50B of the microcapsule B is preferably more than 40 μm and less than 150 μm. When D50B of the microcapsule B is more than 40 μm, the effect of suppressing color development due to rubbing is more effectively exhibited.

-Number average wall thickness of microcapsule B-
The number average wall thickness of the microcapsule B depends on various conditions such as the material of the capsule wall and D50B, but from the viewpoint of more effectively exerting the function of the microcapsule B, 50 nm to 1000 nm is preferable, and 100 nm to 800 nm. Is more preferred.

The ratio of the number average wall thickness of the microcapsule B to the D50B of the microcapsule B (that is, the number average wall thickness / D50B ratio) is preferably 2.0 × 10 ^{−3 to} 1.5 × 10 ^−2. , 2.5 × 10 ^{−3 to} 8.0 × 10 ⁻³ .

  The microcapsule B is a capsule that does not include the electron-donating dye precursor that is a coloring component.

  "The microcapsule B does not include the electron-donating dye precursor" means that the electron-donating dye precursor is not substantially included in the microcapsule B, and is preferably 0 (zero) mass%. .

  Microcapsule B has the same composition (capsule wall material, etc.), manufacturing conditions, and capsule properties as microcapsule A, except that it contains a specific solvent and a specific polar organic compound and does not include an electron-donating dye precursor. (E.g., capsule wall thickness, particle size, etc.).

  The microcapsule B may further include an auxiliary solvent, an additive, and the like, if necessary. In this case, as the components such as the auxiliary solvent and the additive included in the microcapsule B, the same components as the auxiliary solvent and the additive that can be included in the microcapsule A can be selected.

The material for pressure measurement according to the present disclosure may include two or more types of microcapsules A having different median diameters, and may include two or more types of microcapsules B having different median diameters.
When two or more types of microcapsules A having different median diameters are included, the number of large-diameter microcapsules that are destroyed decreases as the pressure increases, and the small-diameter microcapsules subsequently break down and develop color. The color density in the region is improved, and as a result, the material for pressure measurement is more excellent in the density gradation in the high density region.

  The method for producing the microcapsules A and B described above is not particularly limited, and a conventionally known method can be applied. For example, paragraphs 0036 to 0044 of JP-A-2009-019949 can be used. You can refer to the method.

  Hereinafter, a more specific configuration example of the pressure measurement material of the present disclosure will be described, but the pressure measurement material of the present disclosure is not limited to the following embodiments.

The material for pressure measurement according to the present disclosure preferably has a so-called two-sheet type configuration including a first material including a color former layer and a second material including a color developer layer.
The material for pressure measurement according to the present disclosure may have a so-called mono-sheet type having a laminated structure including a color former layer and a color developer layer on a base material.
Hereinafter, among the pressure measuring materials of the present disclosure, those having a two-sheet type form are referred to as “pressure measuring materials A”, and those having a mono-sheet type form are referred to as “pressure measuring materials B”. There are cases.

In the pressure measurement using the two-sheet type pressure measurement material A, the first material and the second material are oriented such that the surface of the color former layer of the first material and the surface of the color developer layer of the second material are in contact with each other. And superimposed. Specifically, the first material and the second material in a superimposed state are arranged at a site where a pressure or a pressure distribution is measured, and in this state, pressure is applied to the first material and the second material. A measurement can be made.
In the pressure measurement using the mono-sheet type pressure measurement material B, the pressure measurement material B is placed alone at the position where the pressure or the pressure distribution is measured. Can be performed.
The pressure may be any of a point pressure, a linear pressure, and a surface pressure.

  In the pressure-measuring material of the present disclosure, the two-sheet type pressure-measuring material A has a small difference in color density (density difference) for identifying a minute pressure difference in a minute pressure range of 0.05 MPa or less. . For this reason, it can be used particularly preferably in the measurement of pressure or pressure distribution when a surface pressure that makes it difficult to detect a differential pressure is applied.

In the pressure measuring material A or B, the microcapsules A are contained in the color former layer, and the microcapsules B are contained in at least one of the layers constituting the pressure measuring material A or B.
In the layer constituting the pressure-measuring material A or B, the layer containing the microcapsules B may contain only one kind of the microcapsules B, or two or more kinds (for example, two kinds having different median diameters on a volume basis). Or more).

<Pressure measurement material A (2 sheet type)>
When the pressure measurement material of the present disclosure is a two-sheet type (that is, the pressure measurement material A), a first material in which a colorant layer containing microcapsules A is disposed on a first base material; A second material in which a developer layer containing an electron-accepting compound is disposed on a second base material, wherein at least one of the first material and the second material contains microcapsules B. Preferably, there is.

  The details of the microcapsules A and B in the material A for pressure measurement are as described above, and the preferred embodiments are also the same.

  In the material A for pressure measurement, the first material may contain the microcapsules B, and the second material may contain the microcapsules B. In the pressure-measuring material A, both the first material and the second material may contain the microcapsules B, or any one of the first material and the second material may contain the microcapsules B. Good.

In the pressure-measuring material A, the layer containing the microcapsules B includes a color former layer in the first material, a layer other than the color former layer in the first material, a developer layer in the second material, and a layer in the second material. Any layer other than the developer layer may be used.
As for the pressure-measuring material A, an embodiment in which the color former layer in the first material is a layer containing microcapsules B or an embodiment in which the developer layer in the second material is a layer containing microcapsules B is more preferable. .

  Examples of the configuration of the layer containing the microcapsules B in the material A for pressure measurement include, but are not limited to, the following embodiments 1A to 4A. In addition, each embodiment may further include another arbitrary layer (for example, an easy-adhesion layer).

~ Aspect 1A ~
A first material in which a color former layer containing microcapsules A and B is disposed on a first base material, and a second material in which a color developer layer containing a developer is disposed on a second base material The aspect which has.
-Aspect 2A
On the first base material, in order from the first base material side, a color former layer containing microcapsules A, another layer containing microcapsules B, a first material provided, and a second base material An embodiment having a second material provided with a color developer layer containing a color developer.
~ Aspect 3A ~
A first material on which a separate layer containing microcapsules B and a color former layer containing microcapsules A are sequentially arranged on the first base material from the first base material side, and on the second base material Having a second material in which a developer layer is disposed.
-Aspect 4A-
A first material in which a color former layer containing microcapsules A is arranged on a first base material, and a second material in which a developer layer containing a color developer and microcapsules B is arranged on a second base material The aspect which has.

  When at least one of the color former layer in the first material and the color developer layer in the second material contains the microcapsules B, the microcapsules B are more effective in suppressing the color development due to rubbing. Is preferably contained in the color former layer of the first material.

  In the pressure measurement material A, it is preferable that the D50A of the microcapsule A is more than 10 μm and less than 40 μm, and the D50B of the microcapsule B is more than 40 μm and less than 150 μm. More preferable ranges of each of D50A and D50B are as described above.

  When D50B of the microcapsule B is less than 150 μm, unevenness of a layer containing the microcapsule B (for example, unevenness of application in a mode of forming and forming a colorant layer) can be further suppressed. When the microcapsules B are contained in the color former layer and D50B is less than 150 μm, the coefficient of variation (CV value) of the particle size distribution of the color former layer is referred to as CV value. ) Does not become too large, so that the color gradation is further improved. The CV value will be described later.

The pressure-measuring material A may show a density and a density gradation that can be visually recognized or read when the color is developed. From the density after applying the pressure at 0.05 MPa and developing the color, the pressure at 0.04 MPa is obtained. It is preferable that the density difference (ΔD1) obtained by subtracting the density after color development by adding is 0.20 or more.
The ΔD1 color developed from the color former layer is preferably as large as possible, and is preferably 0.20 or more, so that the pressure measurement material of the present disclosure was colored by applying a minute pressure of 0.05 MPa or less. In this case, the density and density gradation that can be visually recognized or read can be reproduced more favorably.
The coloring density is a value measured using a reflection densitometer (for example, RD-19I manufactured by Gredagu Macbeth).

Further, the pressure-measuring material A is superimposed on the color-forming agent layer of the first material by bringing a color-developing agent layer of the second material having the same area as the color-forming agent layer of the first material into contact with the color-forming agent layer; It is preferable that the density difference (ΔD2) obtained by subtracting the density before rubbing from the color development density after rubbing the first material by repeating the movement of the first material 20 times is less than 0.02.
When ΔD2 is less than 0.02, color development to a visually recognizable or readable density due to rubbing or the like is suppressed to a small level.
ΔD2 is preferably as small as possible, more preferably less than 0.01, and even more preferably zero (that is, no color development).

  Hereinafter, the first material and the second material in the pressure measuring material A will be described.

[First material]
The pressure measurement material A includes a first material in which a color former layer containing microcapsules A containing an electron-donating dye precursor is disposed on a first base material.
The first material includes a first base material and a color former layer disposed on the first base material.

[First base material]
The shape of the first base material in the pressure measuring material A may be any of a sheet shape, a film shape, a plate shape, and the like.
When the pressure measuring material is of a two-sheet type, the first base material of the first material and the second base material of the second material may be the same or different.

  Specific examples of the first base material include paper, plastic film, synthetic paper, and the like.

Specific examples of paper include high-quality paper, medium-quality paper, paper-change, neutral paper, acidic paper, recycled paper, coated paper, machine-coated paper, art paper, cast-coated paper, finely-coated paper, tracing paper, Recycled paper and the like can be mentioned.
Specific examples of the plastic film include a polyester film such as a polyethylene terephthalate film, a cellulose derivative film such as cellulose triacetate, a polyolefin film such as polypropylene and polyethylene, and a polystyrene film.
Specific examples of the synthetic paper include those obtained by forming a large number of microvoids by biaxially stretching polypropylene or polyethylene terephthalate (Yupo, etc.), those produced using synthetic fibers such as polyethylene, polypropylene, polyethylene terephthalate, polyamide, and the like. Are laminated on a part of paper, on one side or both sides, and the like.
Among them, a plastic film and a synthetic paper are preferable, and a plastic film is more preferable, from the viewpoint of further increasing the color density generated by pressurization.

[Coloring agent layer]
The color former layer in the first material contains microcapsules A containing an electron-donating dye precursor.
The color former layer may contain only one type of microcapsule A, or may contain two or more types. For example, two or more types of microcapsules A having different volume-based median diameters may be contained. The color former layer may further contain other components as necessary.

  In the first material, the color former layer contains a specific solvent and a specific polar organic compound without encapsulating an electron-donating dye precursor in addition to microcapsules A that contribute to color development when pressure is applied. Microcapsules B that do not develop color under pressure are preferably included, and more preferably microcapsules B having a larger median diameter than microcapsules A (D50A <D50B). When the microcapsule B contains the microcapsule B, when an unintended minute pressure is applied, the microcapsule B is first broken and the microcapsule A is prevented from being broken, so that unexpected color development can be suppressed. Further, when the microcapsule A is destroyed by the specific solvent and the specific polar organic compound released outside the microcapsule, the sensitivity and the coloring property are further improved. Thereby, unnecessary coloring due to rubbing or the like is suppressed, and the measurement performance is further improved.

The content (for example, the coating amount) of the electron-donating dye precursor in the color former layer is from 0.1 g / m ² to 0.1 g / m ^{2 in} terms of mass after drying, from the viewpoint of enhancing color developability in a minute pressure range of 0.05 MPa or less. 5 g / m ² is preferred, 0.1 g / m ^{2 to} 4 g / m ² is more preferred, and 0.2 g / m ^{2 to} 3 g / m ² is even more preferred.

  The content of the microcapsules A in the color former layer (the amount of application when applied) is preferably 50% by mass to 80% by mass, and more preferably 60% by mass to 75% by mass with respect to the total solid content of the color former layer. % Is more preferred.

  When the color former layer contains the microcapsules B, the content of the microcapsules B in the color former layer (the amount of application when applied) is from 5% by mass to the total solid content of the color former layer. 30 mass% is preferable and 10 mass%-25 mass% are more preferable.

The color former layer may contain other components other than the microcapsules A and B.
Other components include water-soluble polymer binders (eg, starch or starch derivative fine powder, buffering agents such as cellulose fiber powder, polyvinyl alcohol, etc.), and hydrophobic polymer binders (eg, vinyl acetate-based binders). Acrylate, styrene-butadiene copolymer latex, etc.), surfactants, inorganic particles (eg, silica particles), fluorescent brighteners, defoamers, penetrants, ultraviolet absorbers, preservatives, and the like.

  Examples of the surfactant used in the color former layer include, for example, sodium alkylbenzene sulfonate (for example, Neogen T of Daiichi Kogyo Seiyaku Co., Ltd.) which is an anionic surfactant, and poly (which is a nonionic surfactant) Oxyalkylene lauryl ether (for example, Neugen LP70 of Daiichi Kogyo Seiyaku Co., Ltd.) and the like.

Examples of the silica particles used in the color former layer include fumed silica and colloidal silica.
Regarding silica particles, examples of commercially available products on the market include the Snowtex series (for example, Snowtex (registered trademark) 30) of Nissan Chemical Industries, Ltd. and the like.

The CV value of the particle size distribution of all the particles contained in the color former layer is preferably 35% to 150%.
When the CV value is within the above range, the particle distribution in the colorant layer, particularly the relative dispersion of the microcapsules, is small, so that the color development property against a minute pressure and the color prevention property due to rubbing and the like are excellently balanced. Becomes
The CV value is preferably from 40% to 110%, more preferably from 40% to 80%.

The CV value represents a relative variation of the particles of the color forming agent layer, and is a value obtained from the following.
CV value (%) = standard deviation / arithmetic mean particle diameter × 100
The arithmetic mean particle size and standard deviation are values calculated by photographing the surface of the color former layer with an optical microscope at a magnification of 150 and measuring the size of all microcapsules in a range of 2 cm × 2 cm.

~ Formation of color former layer ~
The colorant layer in the pressure-measuring material A is formed, for example, by applying (for example, applying) a colorant layer-forming coating solution containing the above-described components of the colorant layer and a liquid component (for example, water) onto the first base material. , And can be formed by drying.
The coating solution for forming a color former layer can be prepared, for example, by preparing an aqueous dispersion of microcapsules A and, if necessary, mixing the aqueous dispersion of microcapsules A with other components.
In the case of forming a color former layer containing two or more types of microcapsules A having different D50A or the like, preferably, an aqueous dispersion is prepared for each of the two or more types of microcapsules A, and the obtained two types are obtained. Using the above aqueous dispersion of microcapsules A, a coating solution for forming a color former layer is prepared.

  When the color former layer contains microcapsules B, the color former layer forming coating liquid for forming the color former layer is preferably prepared by preparing an aqueous dispersion of microcapsules A and an aqueous dispersion of microcapsules B, respectively. Then, a coating liquid for forming a colorant layer is prepared using the obtained aqueous dispersion of microcapsules A, the aqueous dispersion of microcapsules B, and other components.

In the case where the colorant layer is formed by applying the colorant layer-forming coating liquid on the substrate, the coating can be performed by a known coating method.
Examples of the coating method include a coating method using an air knife coater, a rod coater, a bar coater, a curtain coater, a gravure coater, an extrusion coater, a die coater, a slide bead coater, a blade coater, or the like.

The thickness of the color former layer is not particularly limited and can be selected according to the purpose and the like.
The thickness of the color former layer (when the microcapsule diameter is larger than the layer thickness, excluding the microcapsules exposed from the layer surface) is preferably 0.01 μm to 0.10 μm, more preferably 0.02 μm to 0.07 μm.

[Second material]
The pressure measurement material of the present disclosure includes a second material in which a color developer layer containing an electron-accepting compound is disposed on a second substrate.
The second material includes a second base material and a color developer layer disposed on the second base material.

[Second substrate]
As the second base material, the same as the first base material can be used.
In the pressure measurement material of the present disclosure, the material of the first base material and the material of the second base material may be the same or different.

[Developer layer]
The color developer layer contains at least an electron-accepting compound as a color developer, and may contain other components such as a binder, a pigment, and an additive, if necessary. The developer here does not include the developer encapsulated in the microcapsules.

Examples of the electron-accepting compound include an inorganic compound and an organic compound.
Specific examples of the inorganic compound include acid clay, activated clay, attapulgite, zeolite, bentonite, and clay materials such as kaolin.
Specific examples of the organic compound include a metal salt of an aromatic carboxylic acid, a phenol formaldehyde resin, and a metal salt of a carboxylated temper phenol resin.
Among them, acid clay, activated clay, zeolite, kaolin, a metal salt of an aromatic carboxylic acid, and a metal salt of a carboxylated temper phenol resin are preferable, and acid clay, activated clay, kaolin, and a metal salt of an aromatic carboxylic acid are preferred. More preferred.

  Preferred specific examples of the metal salt of an aromatic carboxylic acid include 3,5-di-t-butylsalicylic acid, 3,5-di-t-octylsalicylic acid, 3,5-di-t-nonylsalicylic acid, 3,5 -Di-t-dodecylsalicylic acid, 3-methyl-5-t-dodecylsalicylic acid, 3-t-dodecylsalicylic acid, 5-t-dodecylsalicylic acid, 5-cyclohexylsalicylic acid, 3,5-bis (α, α-dimethylbenzyl) ) Salicylic acid, 3-methyl-5- (α-methylbenzyl) salicylic acid, 3- (α, α-dimethylbenzyl) -5-methylsalicylic acid, 3- (α, α-dimethylbenzyl) -6-methylsalicylic acid, -(Α-methylbenzyl) -5- (α, α-dimethylbenzyl) salicylic acid, 3- (α, α-dimethylbenzyl) -6-ethylsalicylic acid, 3-phenyl-5 Zinc salts, nickel salts, aluminum, etc., such as (α, α-dimethylbenzyl) salicylic acid, carboxy-modified terpene phenolic resin, salicylic acid resin which is a reaction product of 3,5-bis (α-methylbenzyl) salicylic acid and benzyl chloride And calcium salts.

  As the color developer contained in the color developer layer, among the specific organic compounds that can be included in the microcapsule B, a compound that can function as a color developer may be used.

Content in the developer layer of the electron-accepting compound (weight case of applying the coating) ^{is, 0.1g / m 2 ~30g / m} 2 is preferable in dry weight. More preferably, in the case of the inorganic compound was ^{3g / m 2 ~20g / m 2} , in the case of organic compounds was ^{0.1g / m 2 ~5g / m 2} , more preferably, in the case of inorganic compound 5g / ^m is 2 to 15 g / ^{m 2,} in the case of organic compound is 0.2 g ^/ m 2 to 3 g / ^{m 2.}

The developer layer can be formed by preparing a developer for forming a developer layer and forming a film. The color developer layer may be formed, for example, by applying a preparation solution for forming a color developer layer on a support by a method such as coating and drying.
The preparation liquid for forming the color developer layer may be a dispersion liquid in which an electron-accepting compound is dispersed in water or the like.
When the electron-accepting compound is an inorganic compound, the dispersion liquid in which the electron-accepting compound is dispersed can be prepared by mechanically dispersing the inorganic compound in water. In some cases, it can be prepared by mechanically dispersing an organic compound in water or dissolving it in an organic solvent.
For details, the method described in JP-A-8-207435 can be referred to.

  The obtained dispersion liquid of the electron-accepting compound may be used as a preparation liquid (for example, a coating liquid) for forming a color-developing agent layer for forming a color-developing agent layer containing the electron-accepting compound.

  The developer layer may contain, in addition to the above-described electron accepting compound, a binder, a pigment, and additives such as a fluorescent whitening agent, an antifoaming agent, a penetrant, and a preservative.

The developer layer also preferably contains the microcapsules B described above.
The specific polar organic compound contained in the microcapsules B contained in the color developer layer may be a compound having a sensitizing ability or a compound having a coloring ability. One of the preferable embodiments is an embodiment in which the microcapsule B contains a compound having a sensitizing ability as the specific polar organic compound.

  The details of the microcapsules B contained in the developer layer are as described above, and the preferred ranges are also the same.

  When the color developer layer contains the microcapsules B, the content of the microcapsules B in the color developer layer (the amount of coating in the case of coating) is 5% based on the total solid content mass of the color developer layer. It is preferably from 30% by mass to 30% by mass, and more preferably from 10% by mass to 25% by mass.

  Examples of the binder include styrene-butadiene copolymer latex, vinyl acetate-based latex, acrylate-based latex, polyvinyl alcohol, polyacrylic acid, maleic anhydride-styrene-copolymer, starch, casein, gum arabic, and gelatin. , Carboxymethylcellulose, methylcellulose, and other synthetic or natural polymer substances.

  Examples of the pigment include kaolin, calcined kaolin, kaolin aggregates, heavy calcium carbonate, and light calcium carbonate in various forms (rice grain, horn, spindle, iga, sphere, aragonite column, amorphous, etc.). , Talc, rutile type, or anatase type titanium dioxide.

  In the case of forming a color developer layer by applying a preparation solution for color developer layer formation, the coating can be performed by a known coating method, and the same coating method as in the case of forming the color former layer described above. Can be applied.

[Easy adhesion layer]
The first base material or the second base material may be a base material having an easily adhesive layer.
It is preferable that the first material has a first base material, and an easy-adhesion layer and a color-forming agent layer arranged from the first base material side. The easy-adhesion layer is preferably provided to improve the adhesion between the first base material and the color former layer.
In addition, when the composition containing microcapsules is applied to the easy-adhesion layer and dried, the effect of suppressing the microcapsules from interacting with the easy-adhesion layer electrostatically (for example, hydrogen bonding) and aggregating. There is. This improves the effect that the microcapsules are broken by a minute pressure when measuring the pressure.

  The easily adhesive layer may be a layer containing a urethane polymer and / or a blocked isocyanate.

The thickness of the easily adhesive layer is not particularly limited, and can be selected according to the purpose and the like.
The thickness of the easily adhesive layer is preferably from 0.005 μm to 0.2 μm, more preferably from 0.01 μm to 0.1 μm.

<Mono-sheet type pressure measuring material>
When the pressure-measuring material of the present disclosure is a mono-sheet type (that is, the pressure-measuring material B), the pressure-measuring material B is a material that contains an electron-accepting compound on a substrate sequentially from the substrate side. It is preferable that the laminated structure including a coloring agent layer and a coloring agent layer containing microcapsules A is provided, and at least one layer included in the laminated structure contains microcapsules B.
The layer having a laminated structure containing the microcapsules B may be any of a color former layer, a developer layer, and another layer other than the color former layer and the developer layer.

  Examples of the configuration of the layer containing the microcapsules B in the pressure measurement material B include, but are not limited to, the following embodiments 1B to 5B. In addition, each embodiment may further include another arbitrary layer (for example, an easy-adhesion layer).

~ Aspect 1B ~
An embodiment in which a color former layer containing microcapsules A and B and a color developer layer containing a color developer are sequentially arranged on a substrate from the substrate side.
-Aspect 2B
An embodiment in which a developer layer containing a developer, another layer containing microcapsules B, and a color former layer containing microcapsules A are sequentially arranged on a substrate from the substrate side.
-Aspect 3B-
An embodiment in which a color developer layer containing a color developer and microcapsules B and a color former layer containing microcapsules A are sequentially arranged on a substrate from the substrate side.
-Aspect 4B-
An embodiment in which a developer layer containing a developer and a color former layer containing microcapsules A and B are sequentially arranged on a substrate from the substrate side.
-Aspect 5B-
A mode in which a color developer layer containing a color developer, a color former layer containing microcapsules A, and another layer containing microcapsules B are sequentially arranged on a substrate from the substrate side.

One preferred embodiment of the monosheet type pressure measuring material B is a mode in which a developer layer containing a developer contains microcapsules B containing a specific polar organic compound having a sensitizing ability. is there.
In addition, an embodiment in which the microcapsules A and B are in the same layer is also preferable because it is expected that the diffusivity and compatibility of the compound contributing to the color-forming reaction can be improved.

As the substrate in the material for pressure measurement B, the same substrate as the first substrate in the material for pressure measurement A can be used.
The details of the microcapsules A and B in the pressure measurement material B are as described above, and the preferred embodiments are also the same.
The details of each layer such as the color-forming agent layer, the color-developing agent layer, and the separate layer containing the microcapsule B included in the pressure-measuring material B are described in detail below. This is the same as the matter described as each layer such as another layer containing B.
Further, the production of the pressure measurement material B is the same as the production of the pressure measurement material A, except that each layer such as a color former layer and a color developer layer is formed on a single base material. it can.

  Hereinafter, the present invention will be described more specifically with reference to examples. However, the present invention is not limited to the following examples unless it exceeds the gist of the present invention. Unless otherwise specified, “%” and “parts” are based on mass.

[Example 1]
<Preparation of liquid containing microcapsule A1>
A solution A was obtained by dissolving 20 parts of the following compound (A), which is an electron-donating dye precursor, in 57 parts of linear alkylbenzene (JX Energy, grade alkene L).
The resulting solution A was stirred, and 15 parts of synthetic isoparaffin 1 (Idemitsu Kosan Co., Ltd., IP Solvent 1620) and N, N, N ', N'-tetrakis dissolved in 1.2 parts of ethyl acetate were added thereto. (2-Hydroxypropyl) ethylenediamine (ADEKA Corporation, Adeka Polyether EDP-300) 0.2 part was added to obtain a solution B.
The obtained solution A was stirred, and 1.2 parts of a trimethylolpropane adduct of tolylene diisocyanate (DIC Co., Ltd., Vernock D-750) dissolved in 3 parts of ethyl acetate was added thereto. I got
Next, the above solution C was added to a solution in which 9 parts of polyvinyl alcohol (PVA-205, Kuraray Co., Ltd.) was dissolved in 140 parts of water, and emulsified and dispersed. 340 parts of water was added to the obtained emulsion, and the mixture was heated to 70 ° C. with stirring, stirred for 1 hour, and cooled. Water was further added to the cooled liquid to adjust the solid content concentration.
As described above, a liquid containing microcapsules A1 (solids concentration: 19.6%) containing microcapsules A1 containing an electron-donating dye precursor was obtained. The microcapsule A1 is included in the microcapsule A in the present disclosure.

The microcapsule A1 contained in the liquid containing microcapsules A1 has a volume standard median diameter (D50A) of 30 μm, a number average wall thickness of 0.054 μm, and δ ^A / D50A of 1.8. × 10 ⁻³ .

The median diameter (D50A) and the number average wall thickness of the microcapsules A1 were calculated as follows.
First, a liquid containing microcapsules A1 was applied on a polyethylene terephthalate (PET) sheet having an adhesive layer having a thickness of 75 μm (Toyobo Co., Ltd., Cosmoshine (registered trademark) A4300) and dried to obtain a coating film.
The D50A of the microcapsule A1 was photographed at a magnification of 150 times with a light microscope on the surface of the obtained coating film, and the diameters of all the microcapsules A1 in a range of 2 cm × 2 cm were measured. Based on the obtained results, Calculated.
The number average wall thickness of the microcapsules A1 is determined by preparing a section of the coating film, selecting five microcapsules A1 from the cross section, and measuring the thickness (μm) of each capsule wall with a scanning electron microscope (SEM). The calculated values were calculated by simple averaging.

<Preparation of liquid (1) containing microcapsule B1>
15 parts of synthetic isoparaffin 1 (Idemitsu Kosan Co., Ltd., IP Solvent 1620, specific solvent, pour point: <-70 ° C.) and N, N, N ′, N′-tetrakis (2- Hydroxypropyl) ethylenediamine (Adeka Co., Ltd., Adeka polyether EDP-300) (0.4 parts) was stirred with an aromatic oil (Hisol (registered trademark) SAS296 (1-phenyl-1-xylylethane and 1-phenyl). Solution D was obtained by adding 78 parts of a mixture with -1-ethylphenylethane, Nippon Oil Corporation, specific solvent, pour point: <-47.5 ° C.
The obtained solution D was stirred, and 3 parts of trimethylolpropane adduct of tolylene diisocyanate (DIC Co., Ltd., Burnock D-750) dissolved in 107 parts of ethyl acetate and stearamide (Nippon Kasei) Solution A was obtained by adding 5 parts of Amid AP-1, a specific polar organic compound, melting point: 101 ° C.).
Next, the above solution E was added to a solution in which 69 parts of polyvinyl alcohol (PVA-205, Kuraray Co., Ltd.) was dissolved in 140 parts of water, and emulsified and dispersed. 340 parts of water was added to the obtained emulsion, and the mixture was heated to 70 ° C. with stirring, stirred for 1 hour, and cooled. Water was further added to the cooled liquid to adjust the concentration.

As described above, a liquid containing microcapsules B1 (solids) containing microcapsules B1 encapsulating aromatic oil and isoparaffin as the specific solvent and stearic acid amide as the specific polar organic compound and not including the electron-donating dye precursor. Partial concentration of 19.6%). The microcapsule B1 is included in the microcapsule B in the present disclosure. The specific solvent in the microcapsule B1 contains an aromatic oil as a main solvent.
Stearamide is a specific polar organic compound that functions as a sensitizer.

The microcapsule B1 had a volume standard median diameter (D50B) of 55 μm, a number average wall thickness of 0.10 μm, and δB / D50B of 1.8 × 10 ⁻³ .
The method for measuring the D50B and the number average wall thickness of the microcapsule B1 was the same as the method for measuring the D50A and the number average wall thickness of the microcapsule A1, respectively.

<Preparation of coating solution (1) for forming colorant layer>
18 parts of the liquid containing microcapsules A1 obtained above, 2 parts of the liquid containing microcapsules B1 obtained above, 63 parts of water, 1.8 parts of colloidal silica (Nissan Chemical Co., Ltd., Snowtex (registered trademark) 30), 1.8 parts of a 10% aqueous solution of carboxymethyl cellulose Na (Daiichi Kogyo Seiyaku Co., Ltd., cellogen 5A), 30 parts of a 1% aqueous solution of carboxymethyl cellulose Na (Daiichi Kogyo Seiyaku Co., Ltd., cellogen EP), sodium alkylbenzene sulfonate 0.3 part of a 15% aqueous solution of (Daiichi Kogyo Seiyaku Co., Ltd., Neogen T) and 0.8 parts of a 1% aqueous solution of Neugen LP70 (Daiichi Kogyo Seiyaku Co., Ltd.) are mixed and stirred for 2 hours. Thus, a coating solution (1) for forming a color former layer was obtained.

<Preparation of first material>
The obtained coating solution (1) for forming a colorant layer is coated on a polyethylene terephthalate (PET) sheet having a thickness of 75 μm with an easily adhesive layer (Toyobo Co., Ltd., Cosmoshine (registered trademark) A4300, first base material). Was applied with a bar coater so that the mass after drying was 2.8 g / m ^2, and dried to form a color former layer.
Thus, a first material in which the color former layer containing the microcapsules A1 and B1 was disposed on the first base material was obtained.

<Preparation of coating solution (1) for forming developer layer>
Using a sand grinder, 10 parts of zinc 3,5-di-α-methylbenzylsalicylate, 100 parts of calcium carbonate, 1 part of sodium hexametaphosphate, and 200 parts of water, which are electron-accepting compounds, were subjected to an average particle diameter of all particles. Was 2 μm to obtain a dispersion.
By adding 100 parts of a 10% aqueous solution of polyvinyl alcohol (PVA-203, Kuraray Co., Ltd.), 10 parts of a styrene-butadiene latex as a solid content, and 450 parts of water to the obtained dispersion, an electron accepting property is obtained. A coating solution (1) for forming a developer layer containing a compound was prepared.

<Preparation of second material>
The developer solution forming coating liquid (1) obtained above was coated on a polyethylene terephthalate (PET) sheet (second base material) having a thickness of 75 μm so that the solid content was 4.0 g / m ^2. And dried to form a color developer layer.
As described above, a second material in which a color developer layer containing zinc 3,5-di-α-methylbenzylsalicylate, which is an electron accepting compound, was disposed on the second base material was obtained.

  Thus, a two-sheet type pressure measurement material (1) including the first material and the second material was obtained.

[Example 2]
Example 1 was repeated except that 5 parts of stearamide was changed to 5 parts of zinc 3,5-di-α-methylbenzylsalicylate (melting point: 125 ° C.) in the preparation of the liquid containing microcapsules B1 in Example 1. In the same manner as described above, a two-sheet type pressure measuring material (2) was produced.

[Example 3]
In the preparation of the liquid containing microcapsules B1 of Example 1, except that 5 parts of stearamide was changed to 5 parts of 2,4-dihydroxydiphenyl sulfone (melting point: 184 ° C.), A two-sheet type pressure measuring material (3) was produced.

[Example 4]
Example 1 was repeated except that 5 parts of stearic acid amide was changed to 5 parts of 4-hydroxy-4′-isopropoxydiphenyl sulfone (melting point: 128 ° C.) in the preparation of the microcapsule B1-containing liquid of Example 1. Similarly, a two-sheet type pressure measuring material (4) was produced.

[Example 5]
<Preparation of coating solution (2) for forming colorant layer>
In the preparation of the coating solution (1) for forming a colorant layer in Example 1, except that 2 parts of the liquid containing microcapsules B1 was not used, the colorant layer was formed in the same manner as the coating solution (1) for forming a colorant layer. A coating liquid for formation (2) was prepared.

<Preparation of first material>
The coating solution (2) for forming a colorant layer obtained above was coated on a 75 μm-thick polyethylene terephthalate (PET) sheet having an easily adhesive layer (Toyobo Co., Ltd., Cosmoshine (registered trademark) A4300, first base material). It was applied on the top with a bar coater so that the mass after drying was 2.6 g / m ^2, and dried to form a color former layer.
As described above, a first material in which the color former layer including the microcapsules A and not including the microcapsules B was disposed on the first base material was obtained.

<Preparation of second material>
In the preparation of the developer layer-forming coating liquid (1) of Example 1, the same procedure as in Example 1 was followed, except that 40 parts of the microcapsule B1-containing liquid was further added. 2) was prepared. A second material was prepared in the same manner as in Example 1, except that the coating solution (2) for forming a developer layer was used instead of the coating solution (1) for forming a developer layer.

  Thus, a two-sheet type pressure measuring material (5) including the first material and the second material was obtained.

[Example 6]
The same coating liquid as the coating liquid (1) for the color developer layer and the coating liquid (1) for the color developing layer prepared in Example 1 were prepared.
The coating amount of the developer layer coating solution (1) was coated on a 75 μm-thick polyethylene terephthalate (PET) sheet with an easy-adhesion layer (Toyobo Co., Ltd., Cosmoshine® A4300, base material) Was applied with a bar coater at 4.0 g / m ² to form a color developer layer. Next, the color former layer coating solution (1) was applied by a bar coater at a solid content of 2.8 g / m ² on the developer layer to form a color former layer.
As described above, a mono-sheet type pressure measuring material (6) in which two layers of a color developer layer and a color former layer were sequentially laminated on the substrate in order from the substrate side was obtained.

  Thus, a mono-sheet type pressure measuring material (6) having a color former layer and a color developer layer was obtained.

[Example 7]
Microcapsules B2 containing microcapsules B2 were prepared in the same manner as in Example 1 except that the emulsification conditions were changed so that the capsule particle diameter was 30 μm in the preparation of the liquid (1) containing microcapsules B1 in Example 1. A containing solution (solid content concentration: 19.6%) was prepared.
The microcapsule B2 contained in the microcapsule B2-containing liquid has a volume standard median diameter (D50A) of 30 μm, a number average wall thickness of 0.054 μm, and δ ^A / D50A of 1.8. × 10 ⁻³ .

Same as Example 1 except that 2 parts of microcapsule B2 containing liquid was used instead of 2 parts of microcapsule B1 containing liquid (1) in preparation of coating solution (1) for forming a color former layer of Example 1. Thus, a coating solution (3) for forming a color former layer was prepared.
A first material and a second material were prepared in the same manner as in Example 1 except that the coating solution (3) for forming a colorant layer was used instead of the coating solution (1) for forming a colorant layer. did.

  Thus, a two-sheet type pressure measuring material (7) including the first material and the second material was obtained.

Example 8
In the preparation of the liquid (1) containing the microcapsule B1 in Example 1, synthetic isoparaffin 2 (Idemitsu Kosan Co., Ltd., IP Solvent 2835, specific solvent, pour point: <−60 ° C.) was used instead of synthetic isoparaffin 115 parts. A microcapsule B1-containing liquid (2) containing microcapsules B2 was prepared in the same manner as in Example 1 except that the amount was changed to 15 parts.

Example 1 was repeated except that 2 parts of the microcapsule B1-containing liquid (2) was used instead of 2 parts of the microcapsule B1-containing liquid (1) in the preparation of the coating solution (1) for forming a colorant layer in Example 1. In the same manner as in Example 1, a coating solution (4) for forming a color former layer was prepared.
The first material and the second material were prepared in the same manner as in Example 1 except that the coating solution (4) for forming a colorant layer was used instead of the coating solution (1) for forming a colorant layer. did.

  As described above, a two-sheet type pressure measuring material (8) including the first material and the second material was obtained.

[Comparative Example 1]
<Preparation of microcapsule B3 containing liquid>
In the preparation of the microcapsule B1-containing liquid of Example 1, a microcapsule B3-containing liquid containing the microcapsule B3 was prepared in the same manner as the preparation of the microcapsule B1-containing liquid except that 5 parts of stearamide was not used. (Solids concentration 19.6%).

<Preparation of coating solution (C1) for forming color former layer>
In the preparation of the coating solution (1) for forming a colorant layer in Example 1, except that 2 parts of the liquid containing microcapsules B1 was changed to 2 parts of the liquid containing microcapsules B3, the coating solution (1) for forming a colorant layer was used. In the same manner as in the above, a coating solution (C1) for forming a color former layer was prepared.

<Preparation of first material>
The coating solution (C1) for forming a colorant layer obtained above was coated on a 75 μm-thick polyethylene terephthalate (PET) sheet with an easily adhesive layer (Toyobo Co., Ltd., Cosmoshine® A4300, first base material). A color coat layer was formed on the top by a bar coater so that the weight after drying was 2.8 g / m ² , followed by drying.
As described above, a first material in which the color former layer containing the microcapsules A1 and the microcapsules B3 containing no specific organic compound was disposed on the first base material was obtained.

<Preparation of second material>
The second material was manufactured in the same manner as in Example 1.

  Thus, a two-sheet type comparative pressure measurement material (9) including the first material and the second material was obtained.

[Comparative Example 2]
<Preparation of first material>
In the preparation of the first material of Example 5, the first material was formed in the same manner as in Example 5, except that the color former layer was formed on the first substrate using the color former layer forming coating liquid (2). Was prepared.

  The second material was manufactured in the same manner as in Example 1.

  As described above, a two-sheet type comparative pressure measurement material (10) including the first material and the second material was obtained.

[Comparative Example 3]
In the preparation of the first material of Example 6, except that the specific polar organic compound was not used, in the same manner as in Example 6, two layers of a color developer layer and a color former layer were sequentially formed from the substrate side. A laminated mono-sheet type pressure measuring material (11) was obtained.

<Measurement and evaluation>
The following measurements and evaluations were performed using the obtained pressure measurement materials (1) to (11).
Hereinafter, the pressure measurement materials (1) to (11) are abbreviated as evaluation samples (1) to (11), respectively.

(1) Color gradation (density difference: ΔD1)
For each evaluation sample, the gradation of color development was evaluated based on the density difference between the color density obtained when a pressure of 0.05 MPa was applied and the color density obtained when a pressure of 0.04 MPa was applied. The evaluation method and evaluation criteria are as follows.
In the following evaluation criteria, the larger the numerical value of the evaluation rank, the better the color gradation. The evaluation rank having the best color tone gradation is "5".
Table 1 shows the results.

-Evaluation method-
The two-sheet type pressure measurement materials (1) to (4) and (6) to (10) were cut into a first material and a second material each having a size of 5 cm × 5 cm, and used as evaluation samples.
The evaluation sample was overlaid so that the surface of the colorant layer of the first material and the surface of the colorant layer of the second material were in contact with each other. The superposed first material and second material are placed on a desk between two glass plates having a smooth surface, and then a weight is placed on the two glass plates to form two glass plates. A pressure of 0.04 MPa or 0.05 MPa was applied to the first material and the second material sandwiched between the plates for 120 seconds to develop color.
After pressing, the first material and the second material are peeled off, and the density of the color forming region formed in the color developer layer of the second material is measured using a reflection densitometer RD-19I (manufactured by Gretag Macbeth). did.

The mono-sheet type pressure measuring materials (5) and (11) were cut into a size of 5 cm × 5 cm to obtain a sample for evaluation.
For the mono-sheet type pressure measuring material, the prepared evaluation sample is placed between two glass plates having smooth surfaces and placed on a desk, and then a weight is placed on the two glass plates. A pressure of 0.04 MPa or 0.05 MPa was applied to the sheet sandwiched between the two glass plates for 120 seconds to develop color.
After pressurization, the density of the color-developing region formed in the developer layer of the evaluation sample was measured using a reflection densitometer RD-19I (manufactured by Gretag Macbeth).

  For each evaluation sample whose density in the color-developing region was measured as described above, the density of the color-developing region when a color was applied by applying a pressure of 0.04 MPa from the density of the color-developing region when a pressure of 0.05 MPa was applied. The density was subtracted to calculate the density difference (ΔD1).

-Evaluation criteria-
5: ΔD1 is 0.20 or more.
4: ΔD1 is 0.15 or more and less than 0.20.
3: ΔD1 is 0.12 or more and less than 0.15.
2: ΔD1 is 0.10 or more and less than 0.12.
1: ΔD1 is less than 0.10.

(2) Suppression of color development due to rubbing (density difference: ΔD2)
For each evaluation sample, the suppression of color development due to rubbing was evaluated. The evaluation method and evaluation criteria are as follows. Table 1 shows the results.

~ 2 sheet type ~
-Evaluation method-
The two-sheet type pressure measuring materials (1) to (4) and (6) to (10) were cut into a first material and a second material each having a size of 10 cm × 15 cm, and used as evaluation samples.
The color former layer of the first material and the color developer layer of the second material of the evaluation sample were brought into contact with each other and superimposed, and the first material was repeatedly moved 20 times with respect to the second material in the superimposed state. And scraped.
After the rubbing, the density of the coloring region formed in the color developer layer of the evaluation sample was measured using a reflection densitometer RD-19I (manufactured by Gretag Macbeth).

~ Mono sheet type ~
-Evaluation method-
The mono-sheet type pressure measuring materials (5) and (11) were cut into a size of 10 cm × 15 cm, respectively, to obtain a sample for evaluation.
For each of the pressure-measuring materials (5) and (11), two evaluation samples were prepared. When one of the two evaluation samples is used as an evaluation sample A and the other is used as an evaluation sample B, the base material side of the evaluation sample A is brought into contact with the colorant layer side of the evaluation sample B. The evaluation sample B was repeatedly moved 20 times with respect to the evaluation sample A, and was scraped against the evaluation sample A in the superimposed state.
After the rubbing, the density of the coloring region formed on the coloring agent layer of the evaluation sample B was measured using a reflection densitometer RD-19I (manufactured by Gretag Macbeth).

The density difference (ΔD2) was calculated by subtracting the initial density before rubbing from the color density after rubbing.
It is acceptable that ΔD2 is less than 0.02, preferably 0.01 or less, and more preferably 0.00 (that is, no color development).

  In Table 1, the description of "-" indicates that the corresponding component is not contained or that the corresponding measurement or evaluation is not performed.

The details of the specific solvent described in Table 1 are summarized below.
-Synthetic isoparaffin 1 (Idemitsu Kosan Co., Ltd., IP Solvent 1620, synthetic isoparaffin, pour point: <-70 ° C)
・ Synthetic isoparaffin 2 (Idemitsu Kosan Co., Ltd., IP Solvent 2835, pour point: <−60 ° C.)
-Aromatic oil (mixture of 1-phenyl-1-xylylethane and 1-phenyl-1-ethylphenylethane, Hisol (registered trademark) SAS296: a specific solvent, Nippon Oil Corporation, pour point: <-47. 5 ℃))

As shown in Table 1, in the pressure measuring material of the example, the density difference (ΔD1) of the color development is visible or readable at a small pressure difference (0.01 MPa) between 0.05 MPa and 0.04 MPa. 0.12 or more (evaluation rank 3, 4 or 5), excellent color gradation at a very small pressure of 0.05 MPa or less, and color development due to abrasion is a density difference (ΔD2) Was suppressed to less than 0.02, and it was confirmed that coloring due to rubbing was also suppressed.
On the other hand, the pressure measurement material of Comparative Example 1, which includes the microcapsules A and the microcapsules containing no specific polar organic compound and does not contain the microcapsules B, suppresses the color development due to abrasion, but has a lower color development level. The tonality was inferior in comparison with the materials for pressure measurement of each example.
The pressure-measuring material of Comparative Example 2, which contained only microcapsules A and no microcapsules B, was inferior in both the color gradation and the suppression of color formation due to rubbing.
The pressure-measuring material of Comparative Example 3 of the monosheet type including the microcapsules A and the microcapsules containing no specific polar organic compound and not containing the microcapsules B suppresses the color development due to abrasion, but has the gradation of the color development. The properties were inferior in comparison with the pressure measuring materials of the examples.

The disclosure of Japanese Patent Application No. 2017-129235 filed on June 30, 2017 is incorporated herein by reference in its entirety.
All documents, patent applications, and technical standards mentioned herein are to the same extent as if each individual document, patent application, and technical standard were specifically and individually stated to be incorporated by reference. Incorporated herein by reference.

Claims (7)

  Microcapsules A containing an electron-donating dye precursor, and microcapsules B containing a solvent having a melting point or pour point of 30 ° C. or less and a polar organic compound having a melting point of more than 30 ° C. and not containing an electron-donating dye precursor. And a material for pressure measurement containing.   The pressure measurement material according to claim 1, wherein the polar organic compound having a melting point of more than 30 ° C is a compound having an alkyl group having 12 or more carbon atoms and an amide bond.   The pressure according to claim 1, wherein the polar organic compound having a melting point of more than 30 ° C is at least one selected from the group consisting of salicylic acid compounds, salts of salicylic acid compounds, phenol compounds and sulfonamide compounds. Materials for measurement.   The pressure measurement material according to any one of claims 1 to 3, wherein the volume standard median diameter D50B of the microcapsule B is larger than the volume standard median diameter D50A of the microcapsule A. A first material in which a color former layer containing the microcapsules A is disposed on a first base material;
A second material in which a developer layer containing an electron-accepting compound is disposed on a second substrate;
With
The pressure measurement material according to any one of claims 1 to 4, wherein at least one of the first material and the second material contains the microcapsule B.   On the color former layer of the first material, a color developer layer of the second material having the same area as the color former layer of the first material is brought into contact with the color former layer of the first material and overlapped. The density difference obtained by subtracting the density before rubbing from the color density after rubbing the first material with the second material by repeating the motion 20 times with respect to the second material is less than 0.02. Pressure measuring material.   The density difference obtained by subtracting the density after applying a pressure at 0.04 MPa and the density after applying a pressure at 0.05 MPa to the density after applying a pressure at 0.05 MPa is 0.20 or more. The material for pressure measurement according to any one of the above.