WO2022181285A1 - Uv radiation sensitive member, microcapsule, microcapsule production method, liquid dispersion for forming uv radiation sensitive layer, and uv radiation sensitive kit - Google Patents

Abstract

The present invention provides: a UV radiation sensitive member that exhibits superior sensitivity to the wavelength of 222 nm; microcapsules; a microcapsule production method; a liquid dispersion for forming a UV radiation sensitive layer; and a UV radiation sensitive kit. A UV radiation sensitive member according to the present invention comprises a UV radiation sensitive layer including microcapsules in which a photoactive agent, a color former, and a solvent have been encapsulated, wherein the capsule walls of the microcapsules include at least one resin selected from the group consisting of polyurea compounds having an aliphatic ring, polyurethane urea compounds having an aliphatic ring, and polyurethane compounds having an aliphatic ring, and the peak area ratio X determined by a peak area ratio calculation method X is 30% or lower.

Description

UV sensing member, microcapsule, microcapsule manufacturing method, dispersion liquid for forming UV sensitive layer, UV sensing kit

The present invention relates to an ultraviolet sensing member, microcapsules, a method for producing microcapsules, a dispersion for forming an ultraviolet sensitive layer, and an ultraviolet sensing kit.

Measurement of the amount of ultraviolet rays is carried out in various fields. Specific examples include measurement of the amount of ultraviolet rays applied to an object to be irradiated during the curing reaction of an ultraviolet curable resin, and measurement of the amount of ultraviolet rays applied to an object to be irradiated during ultraviolet sterilization of foods and the like.
As a method for measuring the amount of ultraviolet rays, an ultraviolet photometer is used.
There are various types of ultraviolet light meters, such as ultraviolet light meters using semiconductor electromotive force and ultraviolet light meters using photochromics. For example, Patent Literature 1 discloses, as an ultraviolet photometer, an ultraviolet sensing member having an ultraviolet sensing layer containing capsules containing a color former and a photo-oxidizing agent.

JP 2014-164125 A

Conventional ultraviolet sensing members are assumed to be used in the wavelength region of 300 nm or more. On the other hand, in recent years, deep ultraviolet rays in the wavelength range of 100 to 280 nm (for example, irradiated using low-pressure mercury lamps, light-emitting diodes, excimer lamps, etc.) have been used more often.
The present inventors studied the ultraviolet sensing member described in Patent Document 1 and found that there is room for improvement in the sensitivity at a wavelength of 222 nm. Specifically, since the wavelength region to be measured is different in the conventional ultraviolet sensing member, when the conventional ultraviolet sensing member is irradiated with light having a wavelength of 222 nm at a predetermined integrated illuminance, it cannot develop a sufficient color. The color density of the part had become low. In other words, the inventors have found that the sensitivity at a wavelength of 222 nm (sensitivity to light with a wavelength of 222 nm) is inferior.

SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide an ultraviolet sensing member having excellent sensitivity at a wavelength of 222 nm.
Another object of the present invention is to provide a microcapsule, a method for producing a microcapsule, a dispersion for forming an ultraviolet sensitive layer, and an ultraviolet sensitive kit.

As a result of intensive studies aimed at solving the above problems, the inventors found that the problems can be solved by the configuration shown below, and completed the present invention.

(1) An ultraviolet sensing member having an ultraviolet sensing layer containing microcapsules encapsulating a photoactive agent, a coloring agent, and a solvent,
The capsule wall of the microcapsules contains one or more resins selected from the group consisting of polyurea having an alicyclic ring, polyurethane urea having an alicyclic ring, and polyurethane having an alicyclic ring,
An ultraviolet sensing member having a peak area ratio X of 30% or less determined by a peak area ratio calculation method X to be described later.
(2) The ultraviolet sensing member according to (1), wherein the photoactive agent contains a compound represented by general formula (6) described below.
(3) The ultraviolet sensing member according to (1) or (2), wherein the capsule wall of the microcapsules has a structure derived from a polyisocyanate having an alicyclic ring.
(4) the photoactive agent is a photooxidant;
The ultraviolet sensing member according to any one of (1) to (3), wherein the color former is a color former that develops color upon oxidation.
(5) the photoactive agent is a photoacid generator;
The ultraviolet sensing member according to any one of (1) to (3), wherein the coloring agent is a coloring agent that develops color under the action of an acid.
(6) The ultraviolet sensing member according to (5), wherein the color former contains a compound having an indolylphthalide structure.
(7) The ultraviolet sensing member according to any one of (1) to (6), which senses ultraviolet rays of 200 to 230 nm.
(8) A microcapsule encapsulating a photoactive agent, a coloring agent, and a solvent,
The capsule wall of the microcapsules contains one or more resins selected from the group consisting of polyurea having an alicyclic ring, polyurethane urea having an alicyclic ring, and polyurethane having an alicyclic ring,
A microcapsule having a peak area ratio Y of 30% or less as determined by a peak area ratio calculation method Y described later.
(9) The microcapsule according to (8), wherein the photoactive agent contains a compound represented by general formula (6) described below.
(10) The microcapsule according to (8) or (9), wherein the capsule wall of the microcapsule has a structure derived from a polyisocyanate having an aliphatic ring.
(11) the photoactive agent is a photooxidant;
The microcapsule according to any one of (8) to (10), wherein the coloring agent is a coloring agent that develops color upon oxidation.
(12) the photoactive agent is a photoacid generator;
The microcapsule according to any one of (8) to (10), wherein the coloring agent is a coloring agent that develops color under the action of an acid.
(13) The microcapsule according to (12), wherein the coloring agent contains a compound having an indolylphthalide structure.
(14) A method for producing a microcapsule according to any one of (8) to (13),
mixing a color former, a photoactive agent, a solvent and an emulsifier in water to prepare an emulsion;
Forming a resin wall around oil droplets containing a color former, a photoactive agent and a solvent in an emulsified liquid for encapsulation to form microcapsules.
(15) A dispersion for forming an ultraviolet-sensitive layer, containing the microcapsules according to any one of (8) to (13).
(16) An ultraviolet sensing kit comprising the ultraviolet sensing member according to any one of (1) to (7).

According to the present invention, it is possible to provide an ultraviolet sensing member with excellent sensitivity to a wavelength of 222 nm.
Further, according to the present invention, it is possible to provide microcapsules, a method for producing microcapsules, a dispersion for forming an ultraviolet sensitive layer, and an ultraviolet sensitive kit.

1 is a schematic cross-sectional view showing an example of an embodiment of an ultraviolet sensing member of the present invention; FIG.

The present invention will be described in detail below.
In addition, although description of the constituent elements described below may be made based on a representative embodiment of the present invention, the present invention is not limited to such an embodiment.
In this specification, a numerical range represented by "to" means a range including the numerical values before and after "to" as lower and upper limits.
Further, in the numerical ranges described stepwise in this specification, the upper limit or lower limit described in a certain numerical range may be replaced with the upper limit or lower limit of the numerical range described in other steps. good. Moreover, in the numerical ranges described in this specification, the upper limit or lower limit described in a certain numerical range may be replaced with the values shown in the examples.
Further, in this specification, the solid content means a component that forms a composition layer formed using the composition, and when the composition contains a solvent (for example, an organic solvent, water, etc.), the solvent is means all ingredients except In addition, as long as it is a component that forms a composition layer, a liquid component is also regarded as a solid content.
Further, in this specification, ultraviolet light means light with a wavelength range of 10 to 400 nm.
Moreover, in this specification, (meth)acryl means "at least one of acryl and methacryl".
Moreover, in this specification, the "boiling point" means the boiling point at standard atmospheric pressure.

[UV Sensing Member]
The UV-sensitive member of the present invention is a UV-sensitive member provided with a UV-sensitive layer containing microcapsules encapsulating a photoactive agent, a coloring agent, and a solvent, wherein the capsule wall of the microcapsules comprises an aliphatic ring. polyurea, polyurethane urea having an alicyclic ring, and polyurethane having an alicyclic ring. 30% or less.

Although the detailed mechanism by which the ultraviolet sensing member of the present invention having such a configuration exhibits excellent sensitivity to a wavelength of 222 nm (sensitivity to light having a wavelength of 222 nm) is not clear, the present inventors presume as follows. .
When the ultraviolet sensitive layer of the ultraviolet sensitive member of the present invention is irradiated with ultraviolet rays when measuring the amount of ultraviolet rays, in the area irradiated with ultraviolet rays (ultraviolet irradiated area), the amount of ultraviolet rays (e.g., integrated illuminance) A colored portion (colored image) is formed with the color density. Developing a color with a color density corresponding to the amount of ultraviolet rays means that the colored image has gradation according to the amount of ultraviolet rays.

The above-mentioned main coloring mechanism of the UV-sensitive layer originates from the microcapsules contained in the UV-sensitive layer. When the UV-sensitive layer is irradiated with UV rays, the coloring agent usually develops color within the microcapsules present in the UV-irradiated region. Specifically, the photoactive agent absorbs ultraviolet rays and is activated to generate an acid and/or radical, and the color former reacts with the acid and/or radical to develop a color. At this time, the amount of acid and/or radicals generated from the photoactive agent varies depending on the amount of irradiated ultraviolet rays. The amount is also different. As a result, in the ultraviolet-irradiated region of the ultraviolet-sensitive layer, the color density varies depending on the amount of ultraviolet rays applied, and a colored portion is formed with a color-developed density corresponding to the amount of ultraviolet rays.

Features of the ultraviolet sensing member of the present invention include that the capsule walls of the microcapsules contain a predetermined resin having an alicyclic ring, and that the peak area ratio X, which will be described later, is a predetermined value or less.
The present inventor has found that the reason why the desired effect cannot be obtained in the conventional ultraviolet sensing member is that, first, the material of the capsule wall of the microcapsule often has an aromatic group, and in such cases, light with a wavelength of 222 nm is absorbed by the capsule wall, and the light cannot reach the photoactive agent, resulting in poor sensitivity. Therefore, in the present invention, the above problem is solved by using a predetermined resin containing an alicyclic ring that has excellent transparency at a wavelength of 222 nm.
In addition, the present inventors have found that the contents of microcapsules tend to leak in conventional ultraviolet sensing members, and as a result, the sensitivity at a wavelength of 222 nm is inferior. Since the color former exists in the liquid phase of the solvent inside the microcapsules, the action of the photoactive agent on the color former is good. It is considered that the effect of the coloring property on the coloring property is deteriorated, and the coloring property is deteriorated. It is speculated that the reason why the inclusions tended to leak in the prior art was that the polymerization of the resin constituting the capsule wall of the microcapsules did not progress sufficiently. Therefore, in the present invention, it has been found that if the peak area ratio X, which will be described later, is within a predetermined range, leakage of inclusions from the microcapsules can be suppressed, and as a result, desired effects can be obtained.
Hereinafter, the more excellent sensitivity of the ultraviolet sensing member to a wavelength of 222 nm is also referred to as "the effect of the present invention is more excellent".

Hereinafter, embodiments of the ultraviolet sensing member of the present invention will be described in detail with reference to the drawings.

[First embodiment]
FIG. 1 is a schematic cross-sectional view of one embodiment of an ultraviolet sensing member.
The UV sensitive member 10 comprises a support 12 and a UV sensitive layer 14 disposed on one surface of the support 12 and containing microcapsules containing a photoactive agent and a color former. In the ultraviolet sensing layer 14 irradiated with ultraviolet rays, a coloring portion (not shown) is formed with a coloring density corresponding to the amount of ultraviolet rays.
Although FIG. 1 shows an embodiment in which the ultraviolet sensing member is sheet-shaped, the ultraviolet sensing member is not limited to this embodiment, and various shapes such as a block shape such as a rectangular parallelepiped and a columnar shape can be used as the shape of the ultraviolet sensing member. is. Among them, a sheet-like ultraviolet sensing member, that is, an ultraviolet sensing sheet is preferably used.
Further, as the shape of the sheet-shaped ultraviolet sensing member, various shapes such as square, rectangle, circle, ellipse, polygon other than quadrangle such as hexagon, and irregular shape can be used. Also, the sheet-like ultraviolet sensing member may be elongated.

As will be described later, the ultraviolet sensitive member 10 only needs to have the ultraviolet sensitive layer 14 and does not have to have the support 12 .
Furthermore, although the ultraviolet sensing member 10 shown in FIG. 1 has a two-layer structure of the support 12 and the ultraviolet sensing layer 14, it is not limited to this aspect, and as described later, other layers than the support 12 and the ultraviolet sensing layer 14 are formed. Other layers (eg, reflective layer, gloss layer, filter layer, etc.) may be provided.

The lower limit of the thickness of the ultraviolet sensing member 10 is preferably 5 μm or more, more preferably 25 μm or more. Also, the upper limit is preferably 1 cm or less, more preferably 2 mm or less.
In the following, first, the peak area ratio, which is a feature of the present invention, will be described in detail, and then each member of the ultraviolet sensing member will be described in detail.

<<Peak area ratio X>>
The peak area ratio X is a value calculated by the peak area ratio calculation method X below. This peak area ratio X is an index of how easily the color former leaks from the microcapsules, and if this value is small, it means that the color former hardly leaks from the microcapsules. More specifically, in the following method X, first, the ultraviolet sensing member is immersed in n-propanol for 7 days, thereby eluting the color former encapsulated in the microcapsules contained in the ultraviolet sensing member into n-propanol. to obtain a first solution containing a color former. This first solution is used as a reference for the second solution described later. Next, by immersing the ultraviolet sensing member in n-propanol for 1 hour, the coloring agent contained in the microcapsules contained in the ultraviolet sensing member is eluted into the n-propanol to obtain a second solution containing the coloring agent. there is When the amount of the coloring agent eluted in the second solution is large (in other words, the peak area ratio X is large) with respect to the amount of the coloring agent eluted in the first solution, the coloring agent encapsulated in the microcapsules is This means that the elution occurred in a short time, and that the color former easily leaked from the microcapsules. On the other hand, when the amount of the coloring agent eluted in the second solution is small relative to the amount of the coloring agent eluted in the first solution (in other words, the peak area ratio X is small), the microcapsules encapsulate This means that the color former is less likely to elute from the microcapsules and that the color former is less likely to leak from the microcapsules.
Peak area ratio calculation method X: Two test pieces of the same size are cut out from the ultraviolet sensing member, and one of the test pieces is immersed in n-propanol for 7 days to obtain a first solution, and the other of the test pieces is n - Perform liquid chromatography measurement of the second solution obtained by immersing in propanol for 1 hour, and measure the ratio of the peak area of the coloring agent in the second solution to the area of the peak of the coloring agent in the first solution. It is calculated as the area ratio X.
The procedure for calculating the peak area ratio X will be described in detail below.

First, two specimens of the same size (circular shape with a diameter of 2 cm) are cut out from the ultraviolet sensing member to be measured.
Next, one of the cut test pieces is immersed in n-propanol (20 ml) at room temperature (20 to 25° C.) for 7 days, and the resulting solution is defined as the first solution. At the time of immersion, the material is left to stand without stirring. Incidentally, the test piece is usually taken out from the first solution after 7 days. Avoid volatilization of n-propanol during immersion.
Also, one of the cut test pieces is immersed in n-propanol (20 ml) at room temperature (20 to 25° C.) for 1 hour, and the resulting solution is used as the second solution. At the time of immersion, the material is left to stand without stirring. In addition, the test piece is usually taken out from the second solution after 1 hour.

Next, the obtained first solution and second solution are subjected to liquid chromatography measurement. It should be noted that the injection amounts of the first solution and the second solution are the same when performing the liquid chromatography measurement.
The conditions for liquid chromatography measurement are as follows.
Apparatus: Nexera manufactured by Shimadzu Corporation
Column: Capcell pak C18 UG-120
Eluent: water/methanol Oven: 40°C
Injection: 5 μL
Detection: Maximum absorption wavelength of color former to be detected Flow rate: 0.2 mL/min

Next, the area of the peak of the coloring agent in the first solution (hereinafter also referred to as "peak area 1") is obtained from the liquid chromatography measurement result of the first solution, and the liquid chromatography measurement result of the second solution is obtained. The peak area of the coloring agent in the second solution (hereinafter also referred to as "peak area 2") is obtained from the above, and the ratio of peak area 2 to peak area 1 {(peak area 2/peak area 1) x 100} A peak area ratio X is calculated.
The peak area ratio X is 30% or less, preferably 20% or less, more preferably 10% or less, from the viewpoint that the effects of the present invention are more excellent. Although the lower limit is not particularly limited, it is preferably 0%, and is often 1% or more.

<<Support>>
The support is a member for supporting the ultraviolet sensitive layer.
If the ultraviolet sensitive layer itself can be handled, the ultraviolet sensitive member may not have a support.

Examples of the support include resin sheets, paper (including synthetic paper), cloth (including woven fabric and non-woven fabric), glass, wood, and metal. The support is preferably a resin sheet or paper, more preferably a resin sheet or synthetic paper, and still more preferably a resin sheet.
Materials for the resin sheet include polyethylene-based resin, polypropylene-based resin, cyclic polyolefin-based resin, polystyrene-based resin, acrylonitrile-styrene copolymer, acrylonitrile-butadiene-styrene copolymer, polyvinyl chloride-based resin, fluorine-based resin, Poly(meth)acrylic resins, polycarbonate resins, polyester resins (polyethylene terephthalate, polyethylene naphthalate, etc.), polyamide resins such as nylon, polyimide resins, polyamideimide resins, polyarylphthalate resins, silicone resins, polysulfone-based resins, polyphenylene sulfide-based resins, polyethersulfone-based resins, polyurethane-based resins, acetal-based resins, and cellulose-based resins.
Synthetic papers include biaxially stretched polypropylene or polyethylene terephthalate or the like to form a large number of microvoids (Yupo, etc.), polyethylene, polypropylene, polyethylene terephthalate, and polyamide, and other synthetic fibers. Examples include a part of paper, a product laminated on one side or both sides of the paper, and the like.

Another preferred embodiment of the resin sheet is a white resin sheet in which a white pigment is dispersed in a resin. Examples of the material of the resin in the white resin sheet include the same materials as those of the resin sheet described above.
The white resin sheet has UV reflectivity. Therefore, when the support is a white resin sheet, the ultraviolet rays irradiated to the ultraviolet sensing member are reflected by the support, so that scattering of the ultraviolet rays inside the ultraviolet sensing member can be suppressed. As a result, the detection accuracy of the amount of ultraviolet rays of the ultraviolet sensing member can be further improved.

As the white pigment, reference can be made to the white pigment described in paragraph 0080 of WO 2016/017701, the contents of which are incorporated herein.
The white resin sheet is preferably, for example, a white polyester sheet, more preferably a white polyethylene terephthalate sheet.
Commercially available white resin sheets include Yupo (manufactured by Yupo Corporation), Lumirror (manufactured by Toray Industries, Inc.), and Crisper (manufactured by Toyobo Co., Ltd.).

The lower limit of the thickness of the support is preferably 5 µm or more, more preferably 25 µm or more, and even more preferably 50 µm or more. The upper limit is preferably 1 cm or less, more preferably 2 mm or less, and even more preferably 500 μm or less.

<<Ultraviolet Sensing Layer>>
The UV-sensitive layer includes microcapsules (hereinafter also referred to as "specific microcapsules") containing a photoactive agent and a color former.
The various components that may be included in the UV-sensitive layer are detailed below.

<Specific microcapsules>
The UV sensitive layer contains specific microcapsules.
The specific microcapsules have a peak area ratio Y of 30% or less, which is obtained by the peak area ratio calculation method Y below.
Peak area ratio calculation method Y: A third solution obtained by mixing a dispersion obtained by mixing specific microcapsules and water with n-propanol and leaving it for 7 days, and specific microcapsules and water Dispersion B obtained by mixing and n-propanol are mixed and allowed to stand for 1 hour to obtain a fourth solution, which is subjected to liquid chromatography measurement. 4 Calculate the ratio of the peak area of the coloring agent in the solution as the peak area ratio Y.
The peak area ratio Y, like the peak area ratio X described above, is an index of how easily the color former leaks from the microcapsules.
The procedure for calculating the peak area ratio Y will be described in detail below.

First, the specific microcapsules to be measured and water are mixed and stirred to prepare a dispersion liquid A having a solid concentration of 20% by mass so that the microcapsules are uniformly dispersed. A small amount of dispersant may be used if desired. The resulting dispersion A (20 mg) and n-propanol (20 mL) are mixed and allowed to stand for 7 days to obtain a third solution. The specific microcapsules are usually removed by filtration from the obtained third solution after 7 days. Avoid volatilization of n-propanol during mixing.
Separately, according to the same procedure as above, the specific microcapsules and water are mixed to prepare dispersion liquid B, mixed with dispersion liquid B (20 mg) and n-propanol (20 mL), and left for 1 hour. The resulting solution is defined as the fourth solution. The specific microcapsules are usually removed by filtration from the obtained fourth solution after 1 hour.
In addition, when the specific microcapsules are in the form of a dispersion liquid, the solid content concentration of the dispersion liquids (dispersion liquid A and dispersion liquid B) may be set to 10 to 30% by mass and the same measurement may be performed.

Next, the obtained third solution and fourth solution are subjected to liquid chromatography measurement. In addition, when performing liquid chromatography measurement, the injection amount of the third solution and the fourth solution is the same.
The conditions for liquid chromatography measurement are as follows.
Apparatus: Nexera manufactured by Shimadzu Corporation
Column: Capcell pak C18 UG-120
Eluent: water/methanol Oven: 40°C
Injection: 5 μL
Detection: Maximum absorption wavelength of color former to be detected Flow rate: 0.2 mL/min

Next, the area of the peak of the coloring agent in the third solution (hereinafter also referred to as "peak area 3") is obtained from the liquid chromatography measurement result of the third solution, and the liquid chromatography measurement result of the fourth solution is obtained. The peak area of the coloring agent in the fourth solution (hereinafter also referred to as "peak area 4") is obtained from the above, and the ratio of peak area 4 to peak area 3 {(peak area 4/peak area 3) × 100} A peak area ratio Y is calculated.
The peak area ratio Y is 30% or less, preferably 20% or less, more preferably 10% or less, from the viewpoint that the effects of the present invention are more excellent. Although the lower limit is not particularly limited, it is preferably 0%, and is often 1% or more.

The materials that make up the specific microcapsules are detailed below.

A specific microcapsule usually has a core portion and a capsule wall for enclosing a core material forming the core portion (something to be encapsulated (hereinafter also referred to as “encapsulation component”)).
The specific microcapsules include a photoactive agent and a coloring agent as core materials (encapsulation components).

One preferred embodiment of the specific microcapsules is that the photoactive agent is a photo-oxidizing agent and the color former is a color former that develops color upon oxidation.
In another preferred embodiment of the specific microcapsules, the photoactive agent is a photoacid generator, and the color former is a color former that develops color under the action of acid.

As the specific microcapsule, it is preferable to prevent contact between substances inside and outside the capsule due to the substance isolation action of the capsule wall at room temperature. Specifically, JP-A-59-190886 and JP-A-60-242094 can be cited, the contents of which are incorporated herein.

(capsule wall)
The capsule wall of the specific microcapsule is made of one or more resins selected from the group consisting of polyurea having an alicyclic ring, polyurethane urea having an alicyclic ring, and polyurethane having an alicyclic ring (hereinafter collectively referred to as (Also referred to as “specific resin”).
It is preferable that the capsule walls of the specific microcapsules are substantially composed of the specific resin. The phrase "substantially composed of a specific resin" means that the content of the specific resin is 90% by mass or more, preferably 100% by mass, relative to the total mass of the capsule wall. In other words, the capsule walls of the specific microcapsules are preferably made of the specific resin.

The aliphatic ring possessed by each specific resin may be a monocyclic structure or a polycyclic structure. The number of rings contained in the polycyclic structure is not particularly limited, and examples include 2-3.
The number of carbon atoms contained in the aliphatic ring is not particularly limited, preferably 6-20, more preferably 6-12.
The aliphatic ring may be either a saturated aliphatic ring or an unsaturated aliphatic ring.
Aliphatic rings include, for example, cycloalkane rings (eg, cyclohexane rings), adamantane rings, and norbornene rings.

Polyurea is a polymer having multiple urea bonds and is preferably a reaction product formed from raw materials including polyamine and polyisocyanate.
It should be noted that polyurea can be synthesized using polyisocyanate without using polyamine by utilizing the fact that a part of polyisocyanate reacts with water to form polyamine.
Polyurethane urea is a polymer having urethane bonds and urea bonds, and is preferably a reaction product formed from raw materials containing polyol, polyamine, and polyisocyanate.
Incidentally, when the polyol and the polyisocyanate are reacted, part of the polyisocyanate may react with water to form a polyamine, resulting in a polyurethane urea.
Polyurethane is a polymer having a plurality of urethane bonds, and is preferably a reaction product formed from raw materials containing polyol and polyisocyanate.

The capsule wall of the microcapsule preferably has a structure derived from polyisocyanate having an alicyclic ring, from the viewpoint that the effects of the present invention are more excellent. Among them, the capsule walls of the microcapsules are polyurea having a structure derived from a polyisocyanate having an aliphatic ring, polyurethane urea having a structure derived from a polyisocyanate having an aliphatic ring, and polyisocyanate having an aliphatic ring. It preferably contains one or more resins selected from the group consisting of structured polyurethanes.

The description of the aliphatic ring contained in the polyisocyanate having an aliphatic ring is as described above.
The number of aliphatic rings contained in the polyisocyanate having an aliphatic ring is not particularly limited, and may be 1 or 2 or more, preferably 1 to 3.
The number of isocyanate groups contained in the polyisocyanate having an aliphatic ring is not particularly limited, and is preferably 2 to 10, more preferably 2 to 5, even more preferably 2 to 3.
Aliphatic polyisocyanates include aliphatic diisocyanates such as trimethylene diisocyanate, hexamethylene diisocyanate, propylene-1,2-diisocyanate, butylene-1,2-diisocyanate, cyclohexylene-1,2-diisocyanate, cyclohexane sylene-1,3-diisocyanate, cyclohexylene-1,4-diisocyanate, dicyclohexylmethane-4,4'-diisocyanate, 1,4-bis(isocyanatomethyl)cyclohexane, 1,3-bis(isocyanatomethyl)cyclohexane, isophorone Diisocyanates, lysine diisocyanate, hydrogenated tolylene diisocyanate and hydrogenated xylylene diisocyanate.

Polyisocyanates also include tri- or higher functional polyisocyanates (eg, tri-functional triisocyanate and tetra-functional tetraisocyanate).
Trifunctional or higher polyisocyanates include adducts (adducts) of alicyclic diisocyanates and compounds having 3 or more active hydrogen groups in one molecule (e.g., trifunctional or higher polyols, polyamines or polythiols). ) (adduct-type tri- or more functional polyisocyanate) and trimers of alicyclic diisocyanates (biuret type or isocyanurate type) are preferable.

The capsule wall of the microcapsules may further have aromatic rings. That is, the capsule wall of the microcapsules is selected from the group consisting of polyurea having an aliphatic ring and an aromatic ring, polyurethane urea having an aliphatic ring and an aromatic ring, and polyurethane having an aliphatic ring and an aromatic ring. It may contain one or more resins.
Examples of aromatic rings include aromatic hydrocarbon rings and aromatic heterocyclic rings, and aromatic hydrocarbons are preferably used.
The above aromatic hydrocarbon ring may be either monocyclic or condensed polycyclic.
The number of carbon atoms in the aromatic hydrocarbon ring is not particularly limited, but is preferably 6-30, more preferably 6-18, and even more preferably 6-10.
Examples of the monocyclic aromatic hydrocarbon ring include a benzene ring.
Examples of condensed polycyclic aromatic hydrocarbon rings include naphthalene rings.

Aromatic polyisocyanates include aromatic diisocyanates such as m-phenylene diisocyanate, p-phenylene diisocyanate, 2,6-tolylene diisocyanate, 2,4-tolylene diisocyanate, naphthalene-1,4-diisocyanate, diphenylmethane-4,4'-diisocyanate, 3,3'-dimethoxy-biphenyl diisocyanate, 3,3'-dimethyldiphenylmethane-4,4'-diisocyanate, xylylene-1,4-diisocyanate, xylylene-1,3-diisocyanate, 4-chloroxylylene-1,3-diisocyanate, 2-methylxylylene-1,3-diisocyanate, 4,4'-diphenylpropane diisocyanate and 4,4'-diphenylhexafluoropropane diisocyanate.

Examples of commercially available polyisocyanates include Takenate (registered trademark) D-102, D-103, D-103H, D-103M2, P49-75S, D-110N, D-120N, D-140N, and D-160N. , D-127N, D-170N, D-170HN, D-172N, D-177N, D-204, D-165N, NP1100 (manufactured by Mitsui Chemicals) Sumidule N3300, Desmodur (registered trademark) L75, UL57SP, N3200, N3600, N3900, Z4470BA (manufactured by Sumika Bayer Urethane), Coronate (registered trademark) HL, HX, L, HK (manufactured by Nippon Polyurethane), P301-75E (manufactured by Asahi Kasei), Duranate (registered trademark) TPA -100, TKA-100, TSA-100, TSS-100, TLA-100, 24A-100, TSE-100 (manufactured by Asahi Kasei) and Barnock (registered trademark) D-750 (manufactured by DIC).

Polyols include, for example, aliphatic or aromatic polyhydric alcohols, hydroxypolyesters, and hydroxypolyalkylene ethers.
Specific examples include polyols described in JP-A-60-049991. Examples include ethylene glycol, 1,3-propanediol, 1,4-butanediol, 1,5-pentanediol, 1, 6-hexanediol, 1,7-hebutanediol, 1,8-octanediol, propylene glycol, 2,3-dihydroxybutane, 1,2-dihydroxybutane, 1,3-dihydroxybutane, 2,2-dimethyl- 1,3-propanediol, 2,4-pentanediol, 2,5-hexanediol, 3-methyl-1,5-pentanediol, 1,4-cyclohexanedimethanol, dihydroxycyclohexane, diethylene glycol, 1,2,6 -trihydroxyhexane, 2-phenylpropylene glycol, 1,1,1-trimethylolpropane, hexanetriol, pentaerythritol, pentaerythritol ethylene oxide adduct, glycerin ethylene oxide adduct, glycerin, 1,4-di(2- hydroxyethoxy)benzene, condensation products of aromatic polyhydric alcohols such as resorcinol dihydroxyethyl ether and alkylene oxides, p-xylylene glycol, m-xylylene glycol, α,α'-dihydroxy-p-diisopropylbenzene, 4 ,4′-dihydroxy-diphenylmethane, 2-(p,p′-dihydroxydiphenylmethyl)benzyl alcohol, ethylene oxide adduct of bisphenol A, and propylene oxide adduct of bisphenol A.
The polyol is preferably used in an amount such that the ratio of hydroxyl groups is 0.02 to 2 mol per 1 mol of isocyanate groups.

Examples of polyamines include ethylenediamine, trimethylenediamine, tetramethylenediamine, pentamethylenediamine, hexamethylenediamine, p-phenylenediamine, m-phenylenediamine, piperazine, 2-methylpiperazine, 2,5-dimethylpiperazine, 2- Hydroxytrimethylenediamine, diethylenetriamine, triethylenetriamine, triethylenetetramine, diethylaminopropylamine, tetraethylenepentamine, and amine adducts of epoxy compounds.

Polyisocyanate can also react with water to form polymeric substances.

Polyisocyanates, polyols, and polyamines include, for example, US Pat. No. 3,281,383, US Pat. No. 3,773,695, US Pat. and Japanese Patent Publication No. 48-084086, the contents of which are incorporated herein.

The average particle diameter of the microcapsules is preferably 0.1 to 100 μm in terms of volume average particle diameter. The lower limit is more preferably 0.3 μm or more, and even more preferably 0.5 μm or more. The upper limit is more preferably 10 µm or less, and even more preferably 5 µm or less. When the average particle size (volume average particle size) of the microcapsules is 0.1 μm or more, the core material in the capsules can be more stably protected. On the other hand, when the average particle size (volume average particle size) of the microcapsules is 100 μm or less, the resolution of the colored image is further improved.
The average particle diameter (volume average particle diameter) of the microcapsules can be measured, for example, with a laser analysis/scattering particle size distribution analyzer LA950 (manufactured by Horiba, Ltd.).
When measuring the average particle diameter of microcapsules contained in the ultraviolet sensing member, the average particle diameter (volume average particle diameter) of the microcapsules can be measured with a scanning electron microscope (SEM). Specifically, the surface of the ultraviolet sensitive layer is observed with an SEM at a magnification of 5000, and the average particle size of all microcapsules present in the observed field of view is determined by image analysis. If microcapsules cannot be observed on the surface, a cross-sectional slice is prepared and measured in the same manner as above.
In addition, the above-mentioned microcapsule means a concept including specific microcapsules and other than specific microcapsules.

(color former)
A specific microcapsule encloses a coloring agent.
"Color coupler" means a compound that colors, changes color or decolors. The term “coloration” means that a substance is colored from a substantially colorless state (colorless or weakly colored state). “Discoloration” means a change in color from a specific color to a color different from the specific color (for example, a color change from yellow to red, etc.). Also, "discoloring" means changing from a specific color to a substantially colorless state (a colorless or weakly colored state). For example, a coloring compound means a compound that develops color from a substantially colorless state (colorless or weakly colored state) by acid and/or radicals generated from a photoactive agent. . A compound that develops color by reaction with an acid and/or a radical generated from a photoactive agent, which will be described later, is preferred.
The coloring agent is preferably a compound that develops color by oxidation or a compound that develops color by the action of an acid, more preferably a leuco dye.
Among them, the leuco dye is a compound that develops color by being oxidized from a substantially colorless state (hereinafter also referred to as "oxidative coloring leuco dye"), or a compound that develops color from a substantially colorless state. A compound that develops color under the action of an acid (hereinafter also referred to as "acid-color-forming leuco dye") is more preferred.
The coloring agents may be used singly or in combination of two or more.

The coloring agent is preferably a coloring agent that dissolves in the solvent encapsulated in the specific microcapsules described later. A coloring agent that dissolves in a solvent means a coloring agent that dissolves in an amount of 20 g or more per liter of the solvent at room temperature (20 to 25° C.).

・Oxidative coloring leuco dyes Examples of oxidative coloring leuco dyes include triarylmethanephthalide-based compounds, fluoran-based compounds, phenothiazine-based compounds, indolylphthalide-based compounds, azaindolylphthalide-based compounds, and leuco auramine. compounds, rhodamine lactam compounds, triarylmethane compounds, diarylmethane compounds, triazene compounds, spiropyran compounds, thiazine compounds, and fluorene compounds.
For details of the above compounds, reference can be made to US Pat.

One aspect of the oxidative coloring leuco dye is preferably a compound having one or two hydrogen atoms that develops color by removing electrons.
Such oxidative chromogenic leuco dyes include, for example, (a) aminotriarylmethane, (b) aminoxanthine, (c) aminothioxanthine, (d) amino -9,10-dihydroacridine, (e) aminophenoxazine, (f) aminophenothiazine, (g) aminodihydrophenazine, (h) aminodiphenylmethane, (i) leukindamine, (j) aminohydrocinnamic acid ( cyanethane, leucomethine), (k) hydrazine, (l) leucoin digoid dye, (m) amino-2,3-dihydroanthraquinone, (n) tetrahalo-p,p'-biphenol, (o) 2-(p- hydroxyphenyl)-4,5-diphenylimidazole and (p)phenethylaniline. Among the above (a) to (p), (a) to (i) are colored by losing one hydrogen atom, and (j) to (p) are colored by losing two hydrogen atoms. develop color.

Among these, aminoarylmethanes are preferred, and aminotriarylmethanes are more preferred.
Aminotriarylmethane is preferably a compound represented by the following general formula (L) or an acid salt thereof.

In general formula (L), Ar ¹ represents a phenyl group with R ¹ R ² N-substituents para to the bond to the methane carbon atom specified in formula (A1). Ar ² is a phenyl group having an R ¹ R ² N-substituent para to the bond to the methane carbon atom specified in formula (A1), or a phenyl group specified in formula (A2) ortho-position to the methane carbon atom, an alkyl group (preferably an alkyl group having 1 to 4 carbon atoms), an alkoxy group (preferably an alkoxy group having 1 to 4 carbon atoms), a fluorine atom, a chlorine atom, and, represents a phenyl group having a substituent selected from the group consisting of bromine atoms; R ¹ and R ² each independently represent a hydrogen atom, an alkyl group having 1 to 10 carbon atoms, a 2-hydroxyethyl group, a 2-cyanoethyl group or a benzyl group.
Ar ³ represents the same group as at least one of Ar ¹ and Ar ² , or represents a group different from Ar ¹ and Ar ² . When Ar ³ represents a group different from Ar ¹ and Ar ² , Ar ³ is (B1) an alkyl group (preferably an alkyl group having 1 to 4 carbon atoms), an alkoxy group (preferably alkoxy group), chlorine atom, diphenylamino group, cyano group, nitro group, hydroxy group, fluorine atom, bromine atom, alkylthio group, arylthio group, thioester group, alkylsulfonic acid group, arylsulfonic acid group, sulfonic acid group, A phenyl group optionally having a substituent selected from the group consisting of a sulfonamide group, an alkylamide group, and an arylamide group, (B2) consisting of an amine group, a di-lower alkylamino group, and an alkylamino group a naphthyl group optionally having a substituent selected from the group, (B3) a pyridyl group optionally having an alkyl group, (B4) a quinolyl group, or (B5) having an alkyl group represents an indolinylidene group.

R ¹ and R ² are preferably hydrogen atoms or alkyls having 1 to 4 carbon atoms.
In general formula (L) above, Ar ¹ , Ar ² and Ar ³ are all R ¹ R ² N-substituted para-positions relative to the bond to the methane carbon atom specified in the formula. It preferably represents a phenyl group with a group, preferably the same group.

Specific examples of oxidation chromogenic leuco dyes include tris(4-dimethylaminophenyl)methane, tris(4-diethylaminophenyl)methane, bis(4-diethylaminophenyl)-(4-diethylamino-2-methylphenyl)methane, Bis(4-diethylamino-2-methylphenyl)-(4-diethylaminophenyl)methane, bis(1-ethyl-2-methylindol-3-yl)-phenylmethane, 2-N-(3-trifluoromethylphenyl )-N-ethylamino-6-diethylamino-9-(2-methoxycarbonylphenyl)xanthene, 2-(2-chlorophenyl)amino-6-dibutylamino-9-(2-methoxycarbonylphenyl)xanthene, 2-di Benzylamino-6-diethylamino-9-(2-methoxycarbonylphenyl)xanthene, benzo[a]-6-N,N-diethylamino-9,2-methoxycarbonylphenylxanthene, 2-(2-chlorophenyl)-amino- 6-dibutylamino-9-(2-methylphenylcarboxamidophenyl)xanthene, 3,6-dimethoxy-9-(2-methoxycarbonyl)-phenylxanthene, benzoyl leucomethylene blue, and 3,7-bis-diethylaminophenoxy and sardines.

• Acid-color-forming leuco dye As one aspect of the acid-color-forming leuco dye, it is preferably a compound that develops color by donating electrons or accepting protons such as acids. Specific examples include compounds having partial skeletons such as lactones, lactams, sultones, spiropyrans, esters, and amides, and these partial skeletons are ring-opened or cleaved upon contact with acids or protons.
Leuco dyes that develop color under the action of acid (acid-color-forming leuco dyes) include, for example, 3,3-bis(2-methyl-1-octyl-3-indolyl)phthalide and 6′-(dibutylamino)-2′. -bromo-3′-methylspiro[phthalido-3,9′-xanthene], 3-(4-diethylamino-2-ethoxyphenyl)-3-(1-ethyl-2-methylindol-3-yl)-4- Azaphthalide, 3-(4-diethylamino-2-ethoxyphenyl)-3-(1-n-octyl-2-methylindol-3-yl)phthalide, 3-[2,2-bis(1-ethyl-2- methylindol-3-yl)vinyl]-3-(4-diethylaminophenyl)-phthalide, 2-anilino-6-dibutylamino-3-methylfluorane, 6-diethylamino-3-methyl-2-(2,6 -xylidino)-fluorane, 2-(2-chloroanilino)-6-dibutylaminofluorane, 3,3-bis(4-dimethylaminophenyl)-6-dimethylaminophthalide, 2-anilino-6-diethylamino-3 -methylfluorane, 9-[ethyl(3-methylbutyl)amino]spiro[12H-benzo[a]xanthene-12,1′(3′H)isobenzofuran]-3′-one, 2′-methyl-6 '-(Np-tolyl-N-ethylamino)spiro[isobenzofuran-1(3H),9'-[9H]xanthen]-3-one, 3',6'-bis(diethylamino)-2- (4-Nitrophenyl)spiro[isoindole-1,9′-xanthene]-3-one, 9-(N-ethyl-N-isopentylamino)spiro[benzo[a]xanthene-12,3′-phthalide ], 2′-anilino-6′-(N-ethyl-N-isopentylamino)-3′-methylspiro[phthalide-3,9′-[9H]xanthene], and 6′-(diethylamino)-1 ',3'-dimethylfluorane can be mentioned.

As the coloring agent, a compound having an indolylphthalide structure is preferable because the effects of the present invention are more excellent.
A compound having an indolylphthalide structure is a compound having an indolylphthalide structure as a partial structure. As described above, the compound having an indolylphthalide structure (indolylphthalide-based compound) and the compound having an azaindolylphthalide structure (azaindolylphthalide-based compound) function as color formers. That is, the above compound corresponds to a coloring agent having an indolylphthalide structure (particularly, an acid coloring agent).

The number of indolylphthalide structures in a compound having an indolylphthalide structure is not particularly limited, and may be one or more. Among them, two or more are preferable, and two are more preferable, because the effects of the present invention are more excellent.

As the compound having an indolylphthalide structure, a compound represented by general formula (A) or a compound represented by general formula (B) is preferable, and a compound represented by general formula (B) is more preferable. .

In general formula (A), R ^a1 and R ^a2 each independently represent a hydrogen atom or an optionally substituted alkyl group.
Although the number of carbon atoms in the alkyl group represented by R ^a1 is not particularly limited, it is preferably 1 to 30, more preferably 1 to 20, even more preferably 1 to 12, further preferably 5 to 10, from the viewpoint of better effects of the present invention. is particularly preferred.
Although the number of carbon atoms in the alkyl group represented by R ^a2 is not particularly limited, it is preferably from 1 to 10, more preferably from 1 to 5, and even more preferably from 1 to 3, from the viewpoint of better effects of the present invention.
Among them, R ^a1 and R ^a2 preferably represent an optionally substituted alkyl group, and more preferably an unsubstituted alkyl group, from the viewpoint that the effects of the present invention are more excellent.

R ^a3 represents a hydrogen atom, an optionally substituted alkyl group, or an optionally substituted aryl group.
The number of carbon atoms in the alkyl group represented by R ^a3 is not particularly limited.
The aryl group represented by R ^a3 may have a monocyclic structure or a multicyclic structure.
Among them, R ^a3 is preferably an optionally substituted aryl group, and more preferably a substituted aryl group, from the viewpoint that the effects of the present invention are more excellent.

X ^a represents -O- or -NR ^a4 -.
Among them, -O- is preferable as X ^a in that the effects of the present invention are more excellent.
R ^a4 represents a hydrogen atom, an optionally substituted alkyl group, or an optionally substituted aryl group.
Although the number of carbon atoms in the alkyl group represented by R ^a4 is not particularly limited, it is preferably 1 to 10, more preferably 1 to 5, from the viewpoint that the effects of the present invention are more excellent.
The aryl group represented by R ^a4 may have a monocyclic structure or a multicyclic structure.

Although the molecular weight of the compound represented by general formula (A) is not particularly limited, it is preferably 300 or more, more preferably 500 or more. Although the upper limit is not particularly limited, it is preferably 2000 or less, more preferably 1000 or less.

In general formula (B), R ^b1 to R ^b4 each independently represent a hydrogen atom or an optionally substituted alkyl group.
The number of carbon atoms in the alkyl groups represented by R ^b1 and R ^b3 is not particularly limited, but is preferably 1 to 30, more preferably 1 to 20, even more preferably 1 to 12, from the viewpoint of better effects of the present invention. 5 to 10 are particularly preferred.
The number of carbon atoms in the alkyl groups represented by R ^b2 and R ^b4 is not particularly limited, but is preferably 1 to 10, more preferably 1 to 5, and even more preferably 1 to 3, from the viewpoint of better effects of the present invention.
Among them, R ^b1 to R ^b4 are preferably an optionally substituted alkyl group, more preferably an unsubstituted alkyl group, from the viewpoint that the effects of the present invention are more excellent.

X ^b represents -O- or -NR ^b5 -.
Among them, -O- is preferable as ^Xb because the effect of the present invention is more excellent.
R ^b5 represents a hydrogen atom, an optionally substituted alkyl group, or an optionally substituted aryl group.
Although the number of carbon atoms in the alkyl group represented by R ^b5 is not particularly limited, it is preferably 1 to 10, more preferably 1 to 5, from the viewpoint that the effects of the present invention are more excellent.
The aryl group represented by R ^b5 may have a monocyclic structure or a multicyclic structure.

Although the molecular weight of the compound represented by general formula (B) is not particularly limited, it is preferably 300 or more, more preferably 500 or more. Although the upper limit is not particularly limited, it is preferably 2000 or less, more preferably 1000 or less.

(photoactivator)
A specific microcapsule encloses a photoactive agent. The photoactive agent is not particularly limited as long as it is a compound that is activated by light, but the photoactive agent that is activated by light preferably acts on a color former to develop color, and is a compound that is activated by ultraviolet light. is preferably The photoactive agent is preferably one or more of a photooxidizing agent and a photoacid generator. When the specific microcapsules contain a color former that develops color by oxidation, the photoactive agent preferably contains a photo-oxidizing agent. Preferably, the agent includes a photoacid generator.

Photo-oxidizing agent The photo-oxidizing agent is a compound that can be activated by ultraviolet rays to generate radicals and/or extract the hydrogen atoms of the coloring agent to color the coloring agent. preferable.
Among them, the photo-oxidizing agent is preferably one or more of a radical generator and an organic halogen compound, and more preferably used in combination with a radical generator and an organic halogen compound. When a radical generator and an organic halogen compound are used in combination, the ratio of the content of the radical generator to the organic halogen compound (radical generator/organic halogen compound (mass ratio)) is such that the gradation of the color-developing portion is more excellent. , preferably 0.1 to 10, more preferably 0.5 to 5.

.. Radical generator The radical generator is not particularly limited as long as it is a compound that is activated by ultraviolet rays to generate radicals.
As the radical generator, a hydrogen abstraction type radical generator is preferred. The hydrogen abstraction type radical generator has the effect of abstracting hydrogen atoms from the color former to promote oxidation of the color former.
Radical generators include, for example, the azide polymer described in the summary of the 1968 Spring Research Presentation Meeting of the Photographic Society of Japan on page 55; 2-azidobenzoxazole, benzoylazide, and 2-azidobenzimidazole described in US Pat. Azide compounds of; 3'-ethyl-1-methoxy-2-pyridothiacyanine perchlorate described in US Pat. No. 3,615,568, and 1-methoxy-2-methylpyridinium p-toluenesulfonate, etc.; benzophenone; p-aminophenyl ketone; polynuclear quinone; thioxanthenone;
Among them, one or more selected from the group consisting of lophine dimers and benzophenones are preferred, and lophine dimers are more preferred.
Rophine dimers include, for example, hexaarylbiimidazole compounds.
As the hexaarylbiimidazole-based compound, the compounds described in paragraph 0047 of International Publication No. 2016/017701 can be considered. The contents of which are incorporated herein.
Among them, 2,2'-bis(2-chlorophenyl)-4,4',5,5'-tetraphenyl-1,2'-biimidazole is preferred. Examples of 2,2′-bis(2-chlorophenyl)-4,4′,5,5′-tetraphenyl-1,2′-biimidazole include “B-IMD” (manufactured by Kurogane Kasei Co., Ltd.), And "B-CIM" (manufactured by Hodogaya Chemical Industry Co., Ltd.) can be used.

As lophine dimers, compounds represented by the following general formula (1) are also preferred.

wherein A, B, and D are each independently a carbocyclic or heteroaryl group that is unsubstituted or substituted with a substituent that does not inhibit the dissociation of the dimer to the imidazolyl group or the oxidation of the coloring agent. represents
B and D are each independently preferably unsubstituted or have 1 to 3 substituents, and A is unsubstituted or has 1 to 4 substituents is preferred.
Knowledge known as lophine dimers and the like can be used for the compounds represented by the general formula (1) and methods for producing them. See, for example, US Pat. No. 3,552,973 at column 4, line 22 and column 6, line 3, the contents of which are incorporated herein.

One type of radical generator may be used alone, or two or more types may be mixed and used.

..Organic halogen compound The organic halogen compound can accelerate the oxidation of the coloring agent.
As the organic halogen compound, a compound in which the number of halogen atoms in the molecule is 3 or more is preferable because the gradation of the color-developing portion is more excellent. The upper limit of the number of halogen atoms is preferably 9 or less. The organic halogen compounds are compounds other than lophine dimers and benzophenones.
An organic halogen compound may be used individually by 1 type, and may be used in mixture of 2 or more types.
Examples of organic halogen compounds include compounds represented by the following general formulas (2) to (7).

P ⁰ -CX ₃ (2)
In the formula, P ⁰ represents a hydrogen atom, a halogen atom, an optionally substituted alkyl group, or an optionally substituted aryl group. Each X independently represents a halogen atom.
Halogen atoms represented by P ⁰ and X include fluorine, chlorine, bromine and iodine atoms, preferably chlorine or bromine.
Examples of substituents that the alkyl group and aryl group represented by P ⁰ may have include a hydroxy group, a halogen atom, an alkyl group having 1 to 6 carbon atoms, a haloalkyl group having 1 to 6 carbon atoms, an acetyl group, and , an alkoxy group having 1 to 6 carbon atoms, and the like.

Examples of compounds represented by the general formula (2) include trichloromethane, tribromomethane, carbon tetrachloride, carbon tetrabromide, p-nitrobenzotribromide, bromotrichloromethane, pensitrichloride, hexabromoethane, iodoform, 1,1,1-tribromo-2-methyl-2-propanol, 1,1,2,2-tetrabromoethane, 2,2,2-tribromoethanol, and 1,1,1-trichloro- 2-methyl-2-propanol can be mentioned.

In the formula, R represents a substituent. x represents an integer of 0 to 5;

Examples of substituents represented by R include a nitro group, a halogen atom, an alkyl group having 1 to 3 carbon atoms, a haloalkyl group having 1 to 3 carbon atoms, an acetyl group, a haloacetyl group, and a group having 1 to 3 carbon atoms. An alkoxy group is mentioned.
In addition, when two or more R exist in a formula, R may mutually be same or different.

0 to 3 are preferable for x.

Examples of compounds represented by general formula (3) include o-nitro-α,α,α-tribromoacetophenone, m-nitro-α,α,α-tribromoacetophenone, p-nitro-α,α ,α-tribromoacetophenone, α,α,α-tribromoacetophenone, and α,α,α-tribromo-3,4-cycloacetophenone.

R ¹ -SO ₂ -X ¹ (4)

In the formula, R ¹ represents an optionally substituted alkyl group or an optionally substituted aryl group. X ¹ represents a halogen atom.

The alkyl group represented by R ¹ is preferably an alkyl group having 1 to 20 carbon atoms, more preferably an alkyl group having 1 to 10 carbon atoms, and even more preferably an alkyl group having 1 to 6 carbon atoms.
The aryl group represented by R ¹ is preferably an aryl group having 6 to 20 carbon atoms, more preferably an aryl group having 6 to 14 carbon atoms, and even more preferably an aryl group having 6 to 10 carbon atoms.
Examples of substituents that the alkyl group and aryl group represented by R ¹ may have include a nitro group, a halogen atom, an alkyl group having 1 to 3 carbon atoms, a haloalkyl group having 1 to 3 carbon atoms, an acetyl group, and a haloacetyl. and alkoxy groups having 1 to 3 carbon atoms.
The halogen atom represented by X ¹ includes a fluorine atom, a chlorine atom, a bromine atom and an iodine atom, preferably a chlorine atom, a bromine atom or an iodine atom, more preferably a chlorine atom or a bromine atom.

Examples of compounds represented by general formula (4) include 2,4-dinitrobenzenesulfonyl chloride, o-nitrobenzenesulfonyl chloride, m-nitrobenzenesulfonyl chloride, 3,3′-diphenylsulfonedisulfonyl chloride, and ethanesulfonyl chloride. , p-bromobenzenesulfonyl chloride, p-nitrobenzenesulfonyl chloride, p-3-benzenesulfonyl chloride, p-acetamidobenzenesulfonyl chloride, p-chlorobenzenesulfonyl chloride, p-toluenesulfonyl chloride, methanesulfonyl chloride, and hensensulfonyl chloride. A bromide is mentioned.

R ² -SX ² (5)

In the formula, R ² represents an optionally substituted alkyl group or an optionally substituted aryl group. ^X2 represents a halogen atom.

The alkyl group optionally having substituent(s) and the aryl group optionally having substituent(s) represented by R ² are the same as R ¹ in general formula (4), and the preferred embodiments are also the same. be.
^The halogen atom represented by X2 includes a fluorine atom, a chlorine atom, a bromine atom and an iodine atom, preferably a chlorine atom, a bromine atom or an iodine atom, more preferably a chlorine atom or a bromine atom.

Examples of compounds represented by general formula (5) include 2,4-dinitrobenzenesulfenyl chloride and o-nitrobenzenesulfenyl chloride.

R ³ -L ¹ -CX ³ X ⁴ X ⁵ (6)

In the formula, R ³ represents an optionally substituted aryl group or an optionally substituted heteroaryl group. L ¹ represents -SO- or SO ₂ -. X ³ , X ⁴ and X ⁵ each independently represent a hydrogen atom or a halogen atom. However, not all of X ³ , X ⁴ and X ⁵ are hydrogen atoms.

The aryl group represented by R ³ is preferably an aryl group having 6 to 20 carbon atoms, more preferably an aryl group having 6 to 14 carbon atoms, and even more preferably an aryl group having 6 to 10 carbon atoms.
The heteroaryl group represented by R ³ is preferably a heteroaryl group having 4 to 20 carbon atoms, more preferably a heteroaryl group having 4 to 13 carbon atoms, and still more preferably a heteroaryl group having 4 to 9 carbon atoms.
Examples of substituents that the aryl group and heteroaryl group represented by R ³ may have include a nitro group, a halogen atom, an alkyl group having 1 to 3 carbon atoms, a haloalkyl group having 1 to 3 carbon atoms, an acetyl group, A haloacetyl group and an alkoxy group having 1 to 3 carbon atoms can be mentioned.

The halogen atoms represented by X ³ , X ⁴ and X ⁵ include, for example, a fluorine atom, a chlorine atom, a bromine atom and an iodine atom, preferably a chlorine atom, a bromine atom or an iodine atom. , a chlorine atom or a bromine atom are more preferred.

Examples of compounds represented by general formula (6) include hexabromodimethylsulfoxide, pentabromodimethylsulfoxide, hexabromodimethylsulfone, trichloromethylphenylsulfone, tribromomethylphenylsulfone (BMPS), trichloro-p- Chlorophenylsulfone, Tribromomethyl-p-nitrophenylsulfone, 2-Trichloromethylbenzothiazolesulfone, 4,6-Cymethylpyrimidine-2-tribromomethylsulfone, Tetrabromodimethylsulfone, 2,4-Dichlorophenyl-trichloromethylsulfone sulfone, 2-methyl-4-chlorophenyltrichloromethylsulfone, 2,5-dimethyl-4-chlorophenyltrichloromethylsulfone, 2,4-dichlorophenyltrimethylsulfone, and tri-p-tolylsulfonium trifluoromethanesulfonate; Trichloromethylphenylsulfone and tribromomethylphenylsulfone (BMPS) are preferred.

R ⁴ CX ⁶ X ⁷ X ⁸ (7)

In the formula, ^R4 represents an optionally substituted heteroaryl group. X ⁶ , X ⁷ and X ⁸ each independently represent a hydrogen atom or a halogen atom. However, not all of X ⁶ , X ⁷ and X ⁸ are hydrogen atoms.

The heteroaryl group represented by R ⁴ is preferably a heteroaryl group having 4 to 20 carbon atoms, more preferably a heteroaryl group having 4 to 13 carbon atoms, and even more preferably a heteroaryl group having 4 to 9 carbon atoms.
Examples of substituents that the heteroaryl group represented by R ⁴ may have include a nitro group, a halogen atom, an alkyl group having 1 to 3 carbon atoms, a haloalkyl group having 1 to 3 carbon atoms, an acetyl group, a haloacetyl group, An alkoxy group having 1 to 3 carbon atoms can be mentioned.
The halogen atoms represented by X ⁶ , X ⁷ and X ⁸ include, for example, a fluorine atom, a chlorine atom, a bromine atom and an iodine atom, preferably a chlorine atom, a bromine atom or an iodine atom. , a chlorine atom or a bromine atom are more preferred.

Examples of the compound represented by the general formula (7) include tribromoquinaldine, 2-tribromomethyl-4-methylquinoline, 4-tribromomethylpyrimidine, 4-phenyl-6-tribromomethylpyrimidine, 2 -trichloromethyl-6-nitrobenzothiazole, 1-phenyl-3-trichloromethylpyrazole, 2,5-ditribromomethyl-3,4-dibromothiophene, 2-trichloromethyl-3-(p-butoxystyryl)-1 ,3,4-oxadiazole, 2,6-didolychloromethyl-4-(p-methoxyphenyl)-triazine, and 2-(4-methylphenyl)-4,6-bis(trichloromethyl)-1 , 3,5-triazines.

Among them, the organic halogen compound is a compound represented by the general formula (3), a compound represented by the general formula (6), or a compound represented by the general formula (7), which is superior in terms of the effect of the present invention. is preferable, and a compound represented by the general formula (6) is more preferable. Although the reason why the effect of the present invention is superior is not clear, it is presumed that the compound represented by the general formula (6) has good compatibility with a wavelength of 222 nm.
The halogen atom contained in the above compound is preferably a chlorine atom, a bromine atom, or an iodine atom, and more preferably a chlorine atom or a bromine atom.

The organic halogen compounds may be used singly or in combination of two or more.

Photo-acid generator The photo-acid generator is preferably a compound that is cleaved by ultraviolet rays to generate an acid, and that can color the color former by the action of the acid.
Examples of the photoacid generator include nonionic photoacid generators and ionic photoacid generators, and nonionic photoacid generators are preferred because the effects of the present invention are more excellent. Examples of nonionic photoacid generators include organic halogen compounds and oxime compounds. Among them, organic halogen compounds are preferred in that the effects of the present invention are more excellent, and compounds represented by the above-described general formula (6). is more preferred.
As the organic halogen compound, a compound having 3 or more halogen atoms in the molecule is preferable because the gradation of the color-developing portion is more excellent. The upper limit of the number of halogen atoms is preferably 9 or less.
An organic halogen compound may be used individually by 1 type, and may be used in mixture of 2 or more types.
Specific examples of the organic halogen compound include the same organic halogen compounds mentioned as the photo-oxidizing agent in the upper section.

Ionic photoacid generators include diazonium salts, iodonium salts, and sulfonium salts, with iodonium salts or sulfonium salts being preferred. Examples of the ionic photoacid generator include compounds described in JP-A-62-161860, JP-A-61-67034, and JP-A-62-050382. is incorporated herein.
The photoacid generator is not particularly limited as long as it is a compound that generates an acid upon exposure to light. Photoacid generators that generate inorganic acids such as hydrogen halide (e.g., hydrochloric acid), sulfuric acid, and nitric acid can be used. It may be a photoacid generator that generates organic acids such as carboxylic acid and sulfonic acid. Among them, a photo-acid generator that generates an inorganic acid is preferable, and a photo-acid generator that generates a hydrogen halide is more preferable, from the viewpoint that the effects of the present invention are more excellent.

Photoacid generators include triarylsulfonium hexafluorophosphate, triarylsulfonium arsenate, triarylsulfonium antimonate, diaryliodonium hexafluorophosphate, diaryliodonium arsenate, diaryliodonium antimonate, dialkylphenacylsulfonium tetrafluoro Borate, dialkylphenacylsulfonium hexafluorophosphate, dialkyl-4-hydroxyphenylsulfonium tetrafluoroborate, dialkyl-4-hydroxyphenylsulfonium hexafluorophosphate, N-bromosuccinimide, tribromomethylphenylsulfone, diphenyliodine, 2 -trichloromethyl-5-(p-butoxystyryl)-1,3,4-oxadiazole and 2,6-ditrichloromethyl-4-(p-methoxyphenyl)-triazine.

The mass ratio of the photoactive agent to the color former (mass of the photoactive agent/mass of the color former) in the specific microcapsules is not particularly limited, but it is preferably 0.1 to 30 from the viewpoint that the effects of the present invention are more excellent. , 0.3 to 20 are more preferred. It is more preferably 0.4 to 3 when the photoactivator is a photooxidant. When the photoactivator is a photoacid generator, it is preferably 3-20, more preferably 10-20.
The content ratio of the photoactive agent to the color former can be obtained by extracting the UV-sensitive layer with methanol, using a mixture of methanol and water as the eluent, performing liquid chromatography analysis, and calculating the ratio at the maximum absorption wavelength of each component. can be analyzed with

(solvent)
A specific microcapsule encloses a solvent.
The type of solvent is not particularly limited, and includes aromatic solvents and non-aromatic solvents.
"Aromatic solvent" means a solvent having an aromatic ring in the molecule. "Non-aromatic solvent" means a solvent that does not have an aromatic ring in its molecule.

The solvent contained in the specific microcapsules is preferably a solvent compatible with n-propanol. The compatible solvent means a solvent that does not cause phase separation when mixed with n-propanol in the same amount.

The aromatic ring contained in the aromatic solvent includes an aromatic hydrocarbon ring and an aromatic heterocyclic ring, and the aromatic hydrocarbon ring is preferable in that the effect of the present invention is superior.
The aromatic hydrocarbon ring may be either a monocyclic ring or a condensed polycyclic ring, but a monocyclic ring is preferred from the standpoint of superior effects of the present invention.
Moreover, the aromatic hydrocarbon ring may have a substituent. When the aromatic hydrocarbon ring has a plurality of substituents, the substituents may bond together to form an alicyclic ring. In other words, the aromatic hydrocarbon ring may contain an alicyclic structure.
The number of carbon atoms in the aromatic hydrocarbon ring is not particularly limited, but is preferably 6-30, more preferably 6-18, and even more preferably 6-10.
A monocyclic aromatic hydrocarbon ring includes, for example, a benzene ring.
Examples of condensed polycyclic aromatic hydrocarbon rings include naphthalene rings.

The aromatic heterocyclic ring may be either monocyclic or condensed polycyclic.
Moreover, the aromatic heterocyclic ring may have a substituent.

The number of aromatic rings in the aromatic solvent is not particularly limited, and may be one or two or more. In the case where two or more aromatic rings are included, the two aromatic rings are formed into a polycyclic structure (including a condensed polycyclic structure) by bonding substituents that may be present on each aromatic ring to each other. not).

The aromatic solvent may or may not have heteroatoms. An aromatic solvent having a heteroatom is preferable because the effect of the present invention is more excellent.
Aromatic solvents having a heteroatom include, for example, aromatic solvents having an aromatic heterocycle in the molecule and aromatic solvents having a heteroatom and an aromatic hydrocarbon ring in the molecule.
The heteroatom in the aromatic solvent having a heteroatom includes atoms other than carbon atoms and hydrogen atoms, preferably a nitrogen atom, an oxygen atom, a sulfur atom, or a phosphorus atom, more preferably an oxygen atom or a phosphorus atom. . The heteroatom-containing aromatic solvent Y includes a carboxylate ester linking group, a sulfonate ester linking group, and a phosphate ester, in terms of ensuring the transmittance at a wavelength of 222 nm, promoting the color-developing reaction, and improving the sensitivity at a wavelength of 222 nm. It preferably contains at least one selected from the group consisting of a linking group, a carbonyl linking group, and a sulfone linking group.
Examples of the aromatic solvent having a heteroatom include substituted or unsubstituted benzenesulfonate esters such as methyl benzenesulfonate, ethyl benzenesulfonate, methyl toluenesulfonate, and ethyl toluenesulfonate, dimethyl phthalate, phthalate Substituted or unsubstituted phthalic acid diesters such as diethyl acid, dibutyl phthalate, dipentyl phthalate, dihexyl phthalate, and dicyclohexyl phthalate, and triphenyl phosphate (TPP), tricresyl phosphate (TCP), trixylene Nyl phosphate (TXP), cresyl diphenyl phosphate (CDP), 2-ethylhexyl diphenyl phosphate (EHDP), t-butylphenyl diphenyl phosphate (t-BDP), bis-(t-butylphenyl) phenyl phosphate (BBDP), tris aromatic phosphates such as -(t-butylphenyl) phosphate (TBDP), isopropylphenyl diphenyl phosphate (IPP), bis-(isopropylphenyl) diphenyl phosphate (BIPP), and tris-(isopropylphenyl) phosphate (TIPP); mentioned.
Aromatic solvents without heteroatoms include aromatic solvents with no atoms other than carbon and hydrogen atoms.
The aromatic solvent having no heteroatom is preferably an aromatic solvent having no polycyclic aromatic hydrocarbon ring, and an aromatic solvent having one or two monocyclic aromatic hydrocarbon rings. is more preferred, and an aromatic solvent having one or two benzene rings is even more preferred.

The non-aromatic solvent may or may not contain heteroatoms. A non-aromatic solvent having a heteroatom is preferred because the effect of the present invention is more excellent.
The non-aromatic solvent having a heteroatom includes one or more solvents selected from the group consisting of aliphatic carboxylic acids, fatty acid esters, ether solvents, alcohol solvents, amide solvents, and ketone solvents. is preferred. Alcohol-based solvents are preferred from the viewpoint of accelerating the color development reaction, but aliphatic carboxylic acids, fatty acid esters, ether-based solvents, amide-based solvents, and ketone-based solvents are preferred from the viewpoint of suitability for the encapsulation reaction.

You may use a solvent individually by 1 type or in mixture of 2 or more types.
The solvent preferably contains one or more solvents having a boiling point of 100°C or higher, and the boiling point of all the solvents contained in the specific microcapsules is 100°C or higher in order to enhance the effects of the present invention. is more preferred. When the boiling point is 100° C. or higher, the solvent tends to remain without being removed from the capsules when the microcapsules are subjected to a heating step such as a reaction.
The boiling point of the solvent is preferably 120° C. or higher, still more preferably 150° C. or higher, and particularly preferably 200° C. or higher, from the viewpoint that the effect of the present invention is more excellent. Although the upper limit of the boiling point is not particularly limited, it is, for example, 500°C or less.
The mass ratio of the solvent to the coloring agent (mass of solvent/mass of coloring agent) in the specific microcapsules is not particularly limited, but is preferably 1 to 100, more preferably 5 to 50, in that the effect of the present invention is more excellent. preferable.

(other ingredients)
In addition to the components described above, the specific microcapsules may optionally include one or more additives such as reducing agents, light stabilizers, waxes, ultraviolet absorbers, and odor inhibitors. Among them, it is preferable to contain a light stabilizer.

(light stabilizer)
The light stabilizer is not particularly limited as long as it is a material that is stabilized by light, but it preferably acts as a so-called free radical trapping substance that traps free radicals of the activated photoactive agent.
A light stabilizer may be used individually by 1 type, and may use 2 or more types.
Light stabilizers include, for example, 2,5-bis(1,1,3,3-tetramethylbutyl)hydroquinone, hydroquinone, catechol, resorcinol, and polyhydric phenols such as hydroxyhydroquinone, and o- and aminophenols such as aminophenol and p-aminephenol.
The content ratio of the light stabilizer to the photoactive agent (light stabilizer/photoactive agent (molar ratio)) is preferably from 0.0001 to 100, more preferably from 0.0005 to 10.

(reducing agent)
The reducing agent has the function of deactivating the photo-oxidizing agent.
When the specific microcapsules contain a reducing agent, a rapid change in the color density of the UV-sensitive layer due to UV irradiation can be suppressed, and the color density can be easily changed according to the amount of UV irradiation. A reducing agent may also function as an antioxidant.
One reducing agent may be used alone, or two or more reducing agents may be used in combination.
Examples of reducing agents include cyclic phenylhydrazide compounds. Specifically, 1-phenylpyrazolidin-3-one, 1-phenyl-4-methylpyrazolidin-3-one, 1-phenyl-4,4-dimethylpyrazolidin-3-one, 3- methyl-1-p-sulfophenyl-2-pyrazolin-5-one, 3-methyl-1-phenyl-2-pyrazolin-5-one, and 4-hydroxymethyl-4-methyl-1-phenyl-3- pyrazolidinone (Dimezone S, manufactured by Daito Kagaku Co., Ltd.) and the like.
As the reducing agent, the reducing agents described in paragraphs 0072 to 0075 of WO 2016/017701 can be considered, the contents of which are incorporated herein.

(Ultraviolet absorber)
The specific microcapsules may enclose an ultraviolet absorber.
Examples of ultraviolet absorbers include benzotriazole compounds (ultraviolet absorbers having a benzotriazole structure), benzophenone compounds, triazine compounds, and benzodithiol compounds.
Among them, it is preferable that the ultraviolet absorber has a small absorption at a wavelength of 222 nm because the sensitivity at a wavelength of 222 nm is more excellent. Specifically, triazine compounds, benzophenone compounds, and benzodithiol compounds are preferably used.
Moreover, it is preferable that the specific microcapsules do not enclose a benzotriazole compound having a large absorption at a wavelength of 222 nm. When the specific microcapsules encapsulate a benzotriazole compound, the content of the benzotriazole compound is preferably 1% by mass or less, more preferably 0.5% by mass or less, relative to the total mass of the photoactive agent. Although the lower limit is not limited, it is, for example, 0.0001% by mass or more.
Moreover, the content of the benzotriazole compound is preferably 1% by mass or less, more preferably 0.5% by mass or less, relative to the total mass of the color former. Although the lower limit is not limited, it is, for example, 0.0001% by mass or more.
Commercially available triazine compounds include, for example, Adekastab LA-F70 (manufactured by Adeka Co., Ltd.), Tinuvin 1577 ED, Tinuvin 1600 (manufactured by BASF), 2,4-Bis(2,4-dimethylphenyl)-6-(2- hydroxy-4-n-octyloxyphenyl)-1,3,5-triazine, 2-(2,4-Dihydroxyphenyl)-4,6-diphenyl-1,3,5-triazine, and Ethylhexyl Triazone (Tokyo Kasei Co., Ltd. ) made).
Examples of commercially available benzophenone compounds include Chimassorb 81 and Chimassorb 81 FL (manufactured by BASF).
Benzodithiol compounds include, for example, compounds described in International Publication No. 2019/159570.

<Method for producing specific microcapsules>
The method for producing the specific microcapsules is not particularly limited, and examples thereof include known methods such as an interfacial polymerization method, an internal polymerization method, a phase separation method, an external polymerization method, and a coacervation method.

As a method for producing the specific microcapsules, for example, a method including an emulsification step and an encapsulation step shown below is exemplified. In addition, in the encapsulation step, it is preferable to form a resin wall (capsule wall) by an interfacial polymerization method.
Emulsification step: A step of mixing a color former, a photoactive agent, a solvent, and an emulsifier in water to prepare an emulsion Encapsulation step: A color former in the emulsion obtained in the emulsification step and a photoactive A process of forming a specific resin wall (capsule wall) around an oil droplet containing an agent and a solvent for encapsulation

The interfacial polymerization method will be described below by taking as an example a method for producing specific microcapsules having a capsule wall made of polyurea, polyurethane or polyurethaneurea.
Specifically, as the interfacial polymerization method, a coloring agent, a photoactive agent, a solvent, a capsule wall material (e.g., polyisocyanate), and an emulsifier are mixed in water to form an emulsion containing an aqueous phase and an oil phase. (emulsification step), polymerizing the capsule wall material around the oil droplets (oil phase) to form a specific resin wall around the oil droplets for encapsulation, color former and photoactive agent and a step of forming microcapsules containing a solvent (encapsulation step).
As the solvent, a solvent containing an aliphatic structure having a boiling point of less than 100° C. (hereinafter also referred to as a “capsule preparation solvent”) may be used.

In the above emulsification step, the capsule-forming solvent is usually a component that can be added for the purpose of improving the solubility of the core material in the solvent. In many cases, the capsule-forming solvent does not contain an aromatic ring in the molecule. In addition, the capsule-forming solvent is removed by a drying treatment in the method for forming an ultraviolet-sensitive layer, which will be described later. Therefore, it is preferable that the microcapsules in the ultraviolet sensing member do not contain a capsule-forming solvent.
The solvent for capsule preparation is not particularly limited, and examples thereof include ethyl acetate (boiling point 77°C), isopropyl acetate (boiling point 89°C), and methylene chloride (boiling point 40°C).
The capsule-forming solvent may be used singly or in combination of two or more.

Also, the type of emulsifier used in the emulsification step is not particularly limited, and examples thereof include dispersants and surfactants.
Dispersants include, for example, known anionic polymers, nonionic polymers, and colloids that protect water-soluble polymers selected from the group consisting of amphoteric polymers. Specifically, polyvinyl alcohol, Gelatin and cellulose derivatives are mentioned, and polyvinyl alcohol is preferred.
The surfactant is preferably an anionic or nonionic surfactant such as alkylbenzenesulfonate (e.g. sodium dodecylbenzenesulfonate, ammonium dodecylbenzenesulfonate), alkylsulfonate (e.g. lauryl sodium sulfate, dioctyl sulfosuccinate sodium salt) and polyalkylene glycols (eg, polyoxyethylene nonylphenyl ether).

The conditions in the encapsulation step are not particularly limited, but it is preferable to carry out a heat treatment in order to increase the reactivity of the capsule wall material and easily obtain specific microcapsules with little leakage of the color former. That is, it is preferable to form the capsule wall in a heated environment.
The heating temperature is preferably 40° C. or higher, more preferably 45° C. or higher, because the effect of the present invention is more excellent. Although the upper limit of the heating temperature is not particularly limited, it is preferably 60°C or lower, more preferably 55°C or lower. The heating time is preferably from 4 to 48 hours, more preferably from 6 to 24 hours, from the standpoint of better effects of the present invention and productivity.

Also, as other methods for producing specific microcapsules, the methods described in the specifications of US Pat. Nos. 3,726,804 and 3,796,696 can be considered. The contents of which are incorporated herein.

Although the content of the specific microcapsules in the UV-sensitive layer is not particularly limited, it is preferably 50-99% by mass, more preferably 60-90% by mass, based on the total mass of the UV-sensitive layer.

The UV-sensitive layer may contain components other than the specific microcapsules described above.
Other ingredients include, for example, polymeric binders, reducing agents, light stabilizers, cross-linking agents, UV absorbers, sensitizers, and surfactants.

Polymeric binders include polyvinyl alcohol, methylcellulose, ethylcellulose, carboxymethylcellulose, hydroxypropylcellulose, gum arabic, gelatin, polyvinylpyrrolidone, casein, styrene-butadiene latex, acrylonitrile-butadiene latex, polyvinyl acetate, polyacrylate, and , ethicine-vinyl acetate copolymer and the like.
The polymeric binder may be crosslinked. In other words, the polymeric binder may be a crosslinked binder.
The cross-linking agent is not particularly limited, and for example, glyoxazole can be used. Also, the cross-linking agent described in paragraph 0079 of JP-A-2017-167155 can be considered. The contents of which are incorporated herein.

As reducing agents, sensitizers, surfactants, etc., JP-A-1-207741, page 9, lower left column to page 10, upper left column, JP-A-2004-233614, paragraphs 0038 to 0039, 0048 to 0059 can be considered, and the contents thereof are incorporated herein.
In addition, as reducing agents, light stabilizers, ultraviolet absorbers, and surfactants, reducing agents, light stabilizers, ultraviolet absorbers, and surfactants that can be contained in specific microcapsules can also be used.

The mass (solid content coating amount) per unit area of the UV-sensitive layer is not particularly limited, but is preferably 0.1 to 30 g/m ² , more preferably 0.5 to 25 g/m ² , more preferably 1 to 10 g/m 2 . m ² is even more preferred.

The thickness of the ultraviolet sensitive layer is preferably 0.1-30 μm, more preferably 0.5-25 μm, and even more preferably 1-10 μm.

<Method for Forming Ultraviolet Sensing Layer>
A method for forming the ultraviolet sensitive layer is not particularly limited, and known methods may be used.
For example, there is a method in which a support is coated with a dispersion for forming an ultraviolet sensitive layer containing specific microcapsules, and the coated film is subjected to a drying treatment, if necessary.
At least the specific microcapsules are preferably contained in the ultraviolet-sensitive layer-forming dispersion. The microcapsule dispersion obtained by the interfacial polymerization method described above may be used as the dispersion for forming the ultraviolet sensitive layer.
The ultraviolet-sensitive layer-forming dispersion may contain other components that may be contained in the ultraviolet-sensitive layer described above.

The method of applying the dispersion for forming the ultraviolet-sensitive layer is not particularly limited, and examples of coating machines used for coating include air knife coaters, rod coaters, bar coaters, curtain coaters, gravure coaters, and extrusion coaters. , die coaters, slide bead coaters, and blade coaters.

After applying the ultraviolet-sensitive layer-forming dispersion onto the support, the coating film may be subjected to a drying treatment, if necessary. Examples of the drying treatment include heat treatment.

In the above, the method of forming the UV-sensitive layer on the support is described, but it is not limited to the above-described mode. For example, after forming the UV-sensitive layer on the temporary support, peeling off the temporary support, A UV sensitive member may be formed comprising a UV sensitive layer.
The temporary support is not particularly limited as long as it is a peelable support.

<<Other Layers>>
The UV sensitive member may have layers other than the support and UV sensitive layer described above.
Other layers include, for example, a reflective layer, a gloss layer, a filter layer, and a sensitivity adjustment layer.

<Reflective layer>
The UV sensitive member may further comprise a reflective layer.
When the ultraviolet sensitive layer has a reflective layer, the ultraviolet rays irradiated to the ultraviolet sensitive member can be reflected by the layer having ultraviolet reflective properties, so that the scattering of ultraviolet rays inside the ultraviolet sensitive member can be suppressed, and the detection accuracy of the amount of ultraviolet rays can be improved. can be improved.
The reflective layer preferably has a reflectance of 10% or more, more preferably 50% or more, for light with a wavelength of 200 to 380 nm. The reflectance can be measured, for example, by diffuse reflectance measurement using an ultraviolet-visible spectrophotometer (UV-2700/Shimadzu Corporation).
When the support is arranged adjacent to the reflective layer, an adhesion layer may be provided between the support and the reflective layer.
As the reflective layer, the adhesion layer, and the production method thereof, the reflective layer, the adhesion layer, and the production method thereof described in paragraphs 0082 to 0091 of WO 2016/017701 can be referred to. The contents of which are incorporated herein.

<Gloss layer>
The UV sensitive member may further comprise a glossy layer.
When the UV-sensitive layer has a gloss layer, front and back visibility can be improved.
As the glossy layer and its production method, the glossy layer and its production method described in paragraphs 0092 to 0094 of WO 2016/017701 can be referred to. The contents of which are incorporated herein.

<Filter layer>
Preferably, the UV sensitive member further comprises a filter layer.
A filter layer is a layer that selectively transmits light of a specific wavelength. Here, "selectively transmit light of a specific wavelength" means to transmit light of a specific wavelength and block other light. The transmittance of light having a wavelength to be transmitted is, for example, preferably 70% or more, more preferably 80% or more, and even more preferably 90% or more. For example, the transmittance of light having a wavelength to be blocked is preferably 30% or less, more preferably 20% or less, and even more preferably 10% or less.
The filter layer is preferably a filter layer that blocks light with a wavelength of 300 nm or more, and more preferably a filter layer that blocks light with a wavelength of over 230 nm.
The spectral characteristics of the filter layer and the sensitivity adjustment layer described later can be measured using, for example, an ultraviolet-visible spectrophotometer (UV-2700/Shimadzu Corporation).
The filter layer preferably contains an ultraviolet absorber in order to block light of wavelengths other than the specific wavelength. A known ultraviolet absorber can be used as the ultraviolet absorber. In order to block light with a wavelength of more than 230 nm, the filter layer preferably contains an ultraviolet absorber that can be contained in the specific microcapsules.

As for the filter layer and its manufacturing method, the filter layer and its manufacturing method described in paragraphs 0016 to 0026 of International Publication No. 2016/017701 can be considered. The contents of which are incorporated herein.

<Sensitivity adjustment layer>
When the ultraviolet sensing member has a filter layer, it may further have a sensitivity adjusting layer on the surface of the filter layer.
As the sensitivity adjusting layer and its manufacturing method, reference can be made to the sensitivity adjusting layer and its manufacturing method described in paragraphs 0095 to 0109 of WO 2016/017701. The contents of which are incorporated herein.

[Other embodiments]
Embodiments of the ultraviolet sensitive sheet are not limited to the embodiments described above.
As other embodiments other than the embodiments described above, for example, the aspects described in FIGS. 1 to 5 of WO 2016/017701 can be considered, and the contents thereof are incorporated herein. Moreover, as another embodiment, it may be in the form of a kit, which will be described later.
Alternatively, the specific microcapsules may be kneaded into a resin to form a molding. Examples of the resin used for producing the molded body include the materials described as the material of the resin sheet exemplified as the support.

[Characteristics and uses of ultraviolet sensing member]
The ultraviolet sensing member of the present invention can be colored according to the amount of ultraviolet rays, and the difference in color density of the colored portion can be visually confirmed. Moreover, when it is in a sheet form, it is possible to measure the amount of ultraviolet rays over a wide area.

In the ultraviolet sensitive sheet, the slope of the straight line obtained by plotting the logarithm of the integrated illuminance of the light with a wavelength of 222 nm irradiated to the ultraviolet sensitive sheet on the horizontal axis and the color density of the ultraviolet sensitive layer on the vertical axis is suitable for the desired application. It can be adjusted accordingly. For example, when the slope is gradual (in other words, when the gradation is gradual), it can be applied to a wide energy range. be able to.
When the slope γ is within the above range, the color gradation suitable for detecting the amount of ultraviolet light is obtained, and the difference in color density of the colored portion can be easily confirmed visually.
In this specification, "integrated illuminance" is integrated illuminance measured at a wavelength of 222 nm, and includes, for example, a value measured with a 222 nm wavelength UV illuminometer.
The "color density" is a numerical value defined by reflection density D=-log ₁₀ ρ (where ρ is reflectance), and can be measured, for example, with a reflection densitometer (X-Rite310, manufactured by X-Rite).

Moreover, the following method may be used as a method for measuring the difference in color density of the coloring portion.
After irradiating the ultraviolet sensitive sheet with a predetermined ultraviolet ray to develop a color, the obtained sheet is scanned with a scanner (eg, GT-F740/GT-X830, manufactured by Epson) or a reading device such as a smartphone. The image obtained by reading is analyzed for the density of the colored portion using a UV light quantity distribution analysis system (FUD-7010J, manufactured by Fuji Film Co., Ltd.). Note that correction processing and calibration processing may be performed as necessary.

The ultraviolet sensing member can be used, for example, to measure the amount of ultraviolet rays irradiated from an ultraviolet irradiation device when manufacturing a sheet while ultraviolet curing resin is ultraviolet-cured in a roll-to-roll manner. It is also possible to routinely measure the amount of ultraviolet rays during the day, for example, in order to grasp the degree of sunburn caused by ultraviolet rays on people and objects.
In recent years, an indoor sterilization device that sterilizes airborne bacteria and viruses in a manned environment and a sterilization device that sterilizes bacteria and viruses adhering to objects by irradiating ultraviolet rays have been developed. The sterilization device performs sterilization by irradiating ultraviolet rays (UV-C: ultraviolet-C) with a wavelength of 200 to 280 nm. Among them, in a manned environment, ultraviolet rays with a wavelength of 200 to 230 nm (in particular, 222 nm UV) is preferably used. It is also possible to measure the UV dose of such devices using the UV sensitive sheet of the present invention.

[Dispersion for forming ultraviolet sensitive layer and method for producing the same]
The present invention also relates to a dispersion liquid for forming an ultraviolet sensitive layer capable of forming the ultraviolet sensitive layer of the ultraviolet sensitive member described above and a method for producing the same.
The dispersion for forming an ultraviolet sensitive layer of the present invention is a dispersion for forming an ultraviolet sensitive layer containing microcapsules encapsulating a photoactive agent and a color former. That is, the dispersion for forming an ultraviolet-sensitive layer of the present invention corresponds to a dispersion containing the specific microcapsules described above.
The composition of the dispersion for forming an ultraviolet sensitive layer of the present invention will be described in detail below.

The dispersion for forming an ultraviolet sensitive layer of the present invention contains specific microcapsules. The specific microcapsules are the same as the specific microcapsules contained in the ultraviolet sensing member, and the preferred embodiments are also the same.
The content of the specific microcapsules in the ultraviolet-sensitive layer-forming dispersion is preferably 50 to 99% by mass, more preferably 60 to 90% by mass, based on the total solid content in the composition. preferable.

The dispersion for forming an ultraviolet sensitive layer of the present invention may contain other components than the specific microcapsules that can be contained in the ultraviolet sensitive layer. Other components include, for example, polymer binders, cross-linking agents (cross-linking agents for forming cross-linked polymer binders (eg, glyoxazole, etc.)), reducing agents, sensitizers, and surfactants. Specific examples of other components are as described above.
When the ultraviolet-sensitive layer-forming dispersion contains a polymeric binder, the content of the polymeric binder is preferably 1 to 50% by weight, preferably 5 to 40% by weight, based on the total solid content in the composition. %, more preferably 10 to 30% by mass.
When the ultraviolet-sensitive layer-forming dispersion contains a surfactant, the content of the surfactant is preferably 0.01 to 10% by mass, and 0.01 to 10% by mass, based on the total solid content in the composition. It is more preferably 1 to 5% by mass, even more preferably 0.2 to 2% by mass.

The method for producing the ultraviolet-sensitive layer-forming dispersion is not particularly limited, and includes, for example, the above-described method for producing the specific microcapsules. In other words, a manufacturing method including the above-described emulsification step and encapsulation step can be mentioned. The dispersion for forming the ultraviolet sensitive layer has a composition obtained by adding an optional component for forming the ultraviolet sensitive layer to the microcapsule dispersion obtained by the production method including the emulsification step and the encapsulation step described above. It is preferably an object.

[Ultraviolet Sensing Kit]
The present invention also relates to a UV sensing kit containing the UV sensing member described above.
The ultraviolet sensing kit includes at least the ultraviolet sensing member described above.
The specific configuration of the ultraviolet sensing kit is not particularly limited. sheet, more preferably a filter sheet that blocks light with a wavelength of more than 230 nm), light shielding bag (ultraviolet cut bag), judgment sample, limit sample (calibration sheet), condensing jigs such as lenses and concave mirrors, and UV sensing members and another element selected from the group consisting of a holding member that holds.
The holding member may have an opening for irradiating the ultraviolet sensing member held with ultraviolet rays, or the holding member and the judgment sample may be integrated.

The present invention will be described in more detail based on examples below.
The materials, amounts used, proportions, processing details, processing procedures, etc. shown in the following examples can be changed as appropriate without departing from the gist of the present invention. Therefore, the scope of the present invention should not be construed as limited by the examples shown below. In the following, "parts" and "%" are based on mass unless otherwise specified.

[Production of UV Sensing Member]
[Example 1]
Mixture 1 having the following composition was added to a 5% by mass polyvinyl alcohol aqueous solution (202 parts), and then emulsified and dispersed at 20° C. to obtain an emulsion having a volume average particle size of 1 μm. Further, the obtained emulsion was kept stirring at 50° C. for 8 hours. After that, the mixture was returned to room temperature and filtered to obtain an aqueous capsule dispersion.

<Composition of mixed liquid 1>
Color former: Leuco Crystal Violet (trade name “LCV”, manufactured by Yamada Chemical Co., Ltd. 2.5 parts Organic halogen compound: Tribromomethylphenylsulfone (manufactured by Sumitomo Seika Co., Ltd.) 1.25 parts Radical generator: Rofein dimer ( 2,2′-bis(2-chlorophenyl)-4,4′,5,5′-tetraphenyl-1,2′-biimidazole, trade name “B-IMD”, manufactured by Kurogane Kasei) 2.5 Part tricresyl phosphate (manufactured by Fujifilm Wako Pure Chemical Industries, Ltd.) 23 parts Nisseki Hisol SA296 (JX Nikko Nisseki Energy) 7 parts Capsule preparation solvent: ethyl acetate (manufactured by Fujifilm Wako Pure Chemical Industries, Ltd.) 50 parts light stabilizer : 2,5-bis (1,1,3,3-tetramethylbutyl) hydroquinone (manufactured by Tokyo Chemical Industry Co., Ltd.) 0.03 parts Capsule wall material: Polyisocyanate (trade name “Takenate D-120N”, Mitsui Chemicals made) 31 copies

Obtained capsule dispersion (20 parts), polyvinyl alcohol 6 mass% aqueous solution (trade name “Denkasize EP-130”, manufactured by Denka Co., Ltd.) (5 parts), glyoxal (manufactured by Daito Kagaku Co., Ltd.) 0.05 part and a 50% by mass aqueous solution of sodium dodecylbenzenesulfonate (manufactured by Daiichi Kogyo Seiyaku Co., Ltd.) (0.09 parts) to prepare a dispersion for forming an ultraviolet sensitive layer (coating liquid for forming an ultraviolet sensitive layer). did.

The obtained dispersion for forming an ultraviolet sensitive layer was applied to a 188 μm thick white polyethylene terephthalate film (trade name “Crisper K1212” manufactured by Toyobo Co., Ltd.) so that the solid content coating amount was 10 g/m ² , and heated to 105°C. It was dried by heating for 1 minute to prepare an ultraviolet sensitive member comprising a support and an ultraviolet sensitive layer. The UV sensitive layer was about 10 μm.

[Example 2]
An ultraviolet sensing member was produced in the same manner as in Example 1, except that mixed solution 1 was changed to mixed solution 2 having the following composition.
<Composition of mixed solution 2>
Color former: 3,3-bis(2-methyl-1-octyl-3-indolyl)phthalide (manufactured by BASF) 2.5 parts Organic halogen compound: tribromomethylphenylsulfone (Sumitomo Seika Co., Ltd.) 1. 25 parts tricresyl phosphate (manufactured by Fujifilm Wako Pure Chemical Industries, Ltd.) 23 parts Nisseki Hisol SA296 (JX Nippon Oil & Energy) 7 parts Solvent for making capsules: ethyl acetate (manufactured by Fujifilm Wako Pure Chemical Industries, Ltd.) 50 parts photostable Agent: 2,5-bis (1,1,3,3-tetramethylbutyl) hydroquinone (BTHQ, manufactured by Tokyo Chemical Industry Co., Ltd.) 0.03 parts Capsule wall material: Polyisocyanate (trade name “Takenate D-120N”, Mitsui Chemicals, Inc.) 31 copies

[Examples 3-6, Comparative Examples 1-2]
Except for changing the materials used and the emulsification conditions as shown in Table 1, the same procedure as in Example 1 was followed to prepare an ultraviolet sensing member.

The components shown in Table 1 are as follows.

[Capsule wall forming material]
D-120N: Polyisocyanate (trade name “Takenate D-120N”, manufactured by Mitsui Chemicals, Inc., adduct of hydrogenated xylylene-1,3-diisocyanate and trimethylolpropane, 75% by mass ethyl acetate solution)
・ D-140N: Polyisocyanate (trade name “Takenate D-140N”, manufactured by Mitsui Chemicals, an adduct of isophorone diisocyanate and trimethylolpropane, 75% by mass ethyl acetate solution)
D-110N: Polyisocyanate (trade name “Takenate D-110N”, manufactured by Mitsui Chemicals, an adduct of xylylene-1,3-diisocyanate and trimethylolpropane, 75% by mass ethyl acetate solution)

[Color former]
・ LCV: Leuco Crystal Violet (trade name “LCV”, manufactured by Yamada Chemical Industry Co., Ltd.)
- Color former A: 3,3-bis (2-methyl-1-octyl-3-indolyl) phthalide (manufactured by BASF)
・RED500: Refer to the following structural formula

・PinkDCF: 3',6'-bis(diethylamino)-2-(4-nitrophenyl)spiro[isoindole-1,9'-xanthene]-3-one (Pink-DCF, manufactured by Hodogaya Chemical Industry Co., Ltd.)

LCV corresponds to a coloring agent that develops color by oxidation, and coloring agents A, RED500 and PinkDCF correspond to coloring agents that develop color by the action of acid.
LCV, color former A, RED500, and PinkDCF were all color formers dissolved in the solvent contained in each microcapsule. The definition of dissolution is given above.
Moreover, the solvent contained in each microcapsule was compatible with n-propanol. The definition of compatible is as described above.
Ethyl acetate, a solvent for preparing capsules used in Examples and Comparative Examples, did not remain in the microcapsules after preparation of the ultraviolet sensing member. In other words, the microcapsules in the ultraviolet sensing member of the present invention did not contain ethyl acetate.

[Measurement and evaluation]
[Peak area ratio X and peak area ratio Y]
Using the ultraviolet sensing members and microcapsules obtained in each example and comparative example, the peak area ratio X and the peak area ratio Y were calculated according to the method described above.

[Sensitivity (wavelength 222 nm)]
Care222 (registered trademark, manufactured by Ushio Corporation) was used to set the wavelength to 222 nm for the UV-sensitive layer of the UV-sensitive member produced in each example and comparative example, and the integrated illuminance was 1 mJ/cm ² or 3 mJ/cm ² . The distance and time were adjusted to irradiate the light.
Next, an image of the obtained sheet is read using an A4 scanner (GT-F740/GT-X830, manufactured by Epson Corporation), and the obtained image is analyzed by a UV light amount distribution analysis system (FUD-7010J, manufactured by Fujifilm Corporation). was used to analyze the density (DA1) of the colored portion formed in the ultraviolet sensitive layer and colored at each integrated illuminance. Then, the difference (DA1-DA0) between the density of the uncolored portion (DA0) and the density of the colored portion (DA1) was obtained and defined as the sensitivity (ΔDA). Sensitivity evaluation was performed based on the following evaluation criteria. When LCV was used as the color former, the OD-C value was used. .

<Evaluation Criteria>
"A": ΔDA is 0.1 or more at an integrated illuminance of 1 mJ/cm ² and ΔDA is 0.1 or more at an integrated illuminance of 3 mJ/cm ² .
"B": ΔDA is less than 0.1 at an integrated illuminance of 1 mJ/cm ² and ΔDA is 0.1 or more at an integrated illuminance of 3 mJ/cm ² .
"C": ΔDA is less than 0.1 at an integrated illuminance of 1 mJ/cm ² and less than 0.1 at an integrated illuminance of 3 mJ/cm ² .

In Table 1, the "aliphatic ring" column indicates "A" when the resin constituting the capsule wall contains an alicyclic ring, and "B" when it does not.

From the results in Table 1, it was confirmed that the ultraviolet sensing member of the present invention has excellent sensitivity at a wavelength of 222 nm.
It was confirmed that the effects of the present invention are more excellent when the photoactive agent is a photoacid generator and the color former is a color former that develops color under the action of acid (comparison with Examples 1 and 2, etc.). .
It was confirmed that the effects of the present invention are more excellent when the color former is a compound having an indolylphthalide structure (comparison with Examples 4 to 6, etc.).

10 UV Sensing Member 12 Support 14 UV Sensing Layer

Claims (16)

An ultraviolet sensing member comprising an ultraviolet sensitive layer containing microcapsules encapsulating a photoactive agent, a coloring agent, and a solvent,
The capsule wall of the microcapsules contains one or more resins selected from the group consisting of polyurea having an alicyclic ring, polyurethane urea having an alicyclic ring, and polyurethane having an alicyclic ring,
An ultraviolet sensing member, wherein the peak area ratio X determined by the peak area ratio calculation method X below is 30% or less.
Peak area ratio calculation method X: A first solution obtained by cutting two test pieces of the same size from the ultraviolet sensing member and immersing one of the test pieces in n-propanol for 7 days, and the test piece The second solution obtained by immersing the other in n-propanol for 1 hour is subjected to liquid chromatography measurement, and the color former in the second solution is compared with the area of the peak of the color former in the first solution. is calculated as the peak area ratio X. The ultraviolet sensing member according to claim 1, wherein the photoactive agent contains a compound represented by general formula (6).
R ³ -L ¹ -CX ³ X ⁴ X ⁵ (6)
In general formula (6), R ³ represents an optionally substituted aryl group or an optionally substituted heteroaryl group. L ¹ represents -SO- or -SO ₂ -. X ³ , X ⁴ and X ⁵ each independently represent a hydrogen atom or a halogen atom. However, the case where all of X ³ , X ⁴ and X ⁵ are hydrogen atoms is excluded. The ultraviolet sensing member according to claim 1 or 2, wherein the capsule wall of the microcapsules has a structure derived from polyisocyanate having an alicyclic ring. the photoactive agent is a photooxidant;
The ultraviolet sensing member according to any one of claims 1 to 3, wherein the coloring agent is a coloring agent that develops color upon oxidation. the photoactive agent is a photoacid generator,
The ultraviolet sensing member according to any one of claims 1 to 3, wherein the coloring agent is a coloring agent that develops color under the action of an acid. The ultraviolet sensing member according to claim 5, wherein the coloring agent contains a compound having an indolylphthalide structure. The ultraviolet sensing member according to any one of claims 1 to 6, which senses ultraviolet rays of 200 to 230 nm. A microcapsule encapsulating a photoactive agent, a color former, and a solvent,
The capsule wall of the microcapsules contains one or more resins selected from the group consisting of polyurea having an alicyclic ring, polyurethane urea having an alicyclic ring, and polyurethane having an alicyclic ring,
A microcapsule having a peak area ratio Y of 30% or less as determined by the following peak area ratio calculation method Y.
Peak area ratio calculation method Y: A third solution obtained by mixing dispersion liquid A obtained by mixing the microcapsules and water with n-propanol and leaving it for 7 days, and the microcapsules and water. Liquid chromatography measurement of the fourth solution obtained by mixing dispersion B obtained by mixing n-propanol and allowing to stand for 1 hour, respectively, and measuring the peak area of the coloring agent in the third solution to the peak area ratio Y of the color former in the fourth solution. 9. Microcapsules according to claim 8, wherein the photoactive agent comprises a compound represented by general formula (6).
R ³ -L ¹ -CX ³ X ⁴ X ⁵ (6)
In general formula (6), R ³ represents an optionally substituted aryl group or an optionally substituted heteroaryl group. L ¹ represents -SO- or -SO ₂ -. X ³ , X ⁴ and X ⁵ each independently represent a hydrogen atom or a halogen atom. However, the case where all of X ³ , X ⁴ and X ⁵ are hydrogen atoms is excluded. The microcapsule according to claim 8 or 9, wherein the capsule wall of the microcapsule has a structure derived from polyisocyanate having an alicyclic ring. the photoactive agent is a photooxidant;
The microcapsules according to any one of claims 8 to 10, wherein the coloring agent is a coloring agent that develops color upon oxidation. the photoactive agent is a photoacid generator,
The microcapsules according to any one of claims 8 to 10, wherein the coloring agent is a coloring agent that develops color under the action of an acid. The microcapsule according to claim 12, wherein the coloring agent contains a compound having an indolylphthalide structure. A method for producing the microcapsules according to any one of claims 8 to 13,
mixing the color former, the photoactive agent, the solvent, and the emulsifier in water to prepare an emulsion;
forming a wall of the resin around the oil droplets containing the color former, the photoactive agent, and the solvent in the emulsified liquid to encapsulate them to form the microcapsules. Production method. A dispersion for forming an ultraviolet sensitive layer containing the microcapsules according to any one of claims 8 to 13. An ultraviolet sensing kit containing the ultraviolet sensing member according to any one of claims 1 to 7.

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