JP7468974B2 - Method for generating modeling data, method for manufacturing artificial nails, and system for manufacturing artificial nails - Google Patents

Description

The present invention relates to a photocurable composition, an artificial nail, a method for generating modeling data for an artificial nail, a method for manufacturing an artificial nail, and a system for manufacturing an artificial nail.

Nail art, which involves the care, makeup, and decoration of fingernails and toenails, such as nail care, manicures, and pedicures, is widespread. In recent years, nail art, such as nail tips, sculptures, and tip overlays using decorated false nails (i.e., artificial nails), has become increasingly popular.

Nail art is makeup and decoration applied to the nails of the hands and feet. The stores that do nail art are called nail salons, and the technicians who do it are called manicurists. There are various nail art supplies on the market, and many women do their own nail art that rivals that of professionals.
Lacquer paint for automobiles was invented in the United States in the 19th century, and this technology was applied to the development of the nail polish that is used today.
However, while nail polish using lacquer paint is still widely used today, it has a problem of poor adhesion to natural nails and peels off and falls off shortly after application. For this reason, artificial nail materials using dental self-polymerizing resin were developed.

Compared to nail polish that uses lacquer paint, artificial nail materials are stronger and more durable, and have been accepted by some professional manicurists. However, they have not been widely used by general manicurists due to the irritation caused by the acrylic monomers, the irritating odor, and poor usability during application.
However, gel nails that have improved odor and irritation of artificial nail materials and ease of application have recently become the main market. Gel nails currently on the market are high-viscosity liquid materials whose main components are (meth)acrylic monomers and photopolymerization initiators, and are hardened by applying them to bare nails and irritating them with ultraviolet light. Compared to the artificial nail materials that were first developed, these commercially available gel nails have less odor and skin irritation and are easy to apply, so they are accepted by many general manicurists.
Japanese Patent Application Laid-Open No. 2010-37330 discloses an artificial nail composition having improved curability, which is characterized by using a specific photopolymerization initiator.

Japanese Patent Laid-Open Publication No. 2010-110451 proposes an artificial nail having a multi-layer structure that includes an outer layer having a nail shape and an inner layer attached directly or indirectly to the outer layer, as an artificial nail that not only has an excellent fit but also a natural appearance that is adapted to each individual nail, and in which the outer layer and the inner layer work together to form a cross section perpendicular to the longitudinal central axis of the artificial nail as a whole into a desired curved state.
In addition, JP 2015-209375 A describes an artificial nail raw material composition that hardens when irradiated with light, as an artificial nail raw material composition that allows the artificial nail to be easily removed from a natural nail.

In recent years, three-dimensional modeling devices known as 3D printers have been developed and are being used in a variety of fields. When applying 3D printers to the field of nail art, the artificial nails produced are required to have a certain degree of hardness, and a hardening process is necessary for the production of artificial nails. However, during the hardening process, deformation occurs in the artificial nail due to hardening shrinkage, which causes a decrease in manufacturing accuracy and a problem of not being able to obtain a good fit when the artificial nail is worn.

The present invention has been made in consideration of the above facts, and aims to provide a photocurable composition, an artificial nail, a method for generating modeling data that enables the manufacture of an artificial nail with high accuracy, a method for manufacturing an artificial nail, and a system for manufacturing an artificial nail.

In recent years, three-dimensional printers (i.e., 3D printers) have been developed and are being applied to various fields. When applying 3D printers to the field of nail art, it is assumed that conventional curable resins for gel nails are used by directly applying them to bare nails and curing them, and they are not suitable for use in creating nail tips by stereolithography, and have problems with the bending strength, bending modulus, bending resistance, tensile strength, elongation, etc. of the cured product.
When a photo-modeled object, preferably an artificial nail, is produced using a 3D printer, taking into consideration practicality, the photocurable composition after photocuring is required to have excellent flexural strength (i.e., flexural strength), flexural modulus, flexural resistance, tensile strength and elongation.

That is, an object of one embodiment of the present invention is to provide a photocurable composition that can be used in photopolymerization and that, after photocuring, has excellent bending strength and bending modulus, and further has excellent bending resistance, tensile strength and elongation.
Another object of one embodiment of the present invention is to provide an artificial nail which is a cured product of the above-mentioned photocurable composition, and which has excellent flexural strength and flexural modulus, as well as excellent flexural resistance, tensile strength and elongation.

Means for Solving the Problems The present inventors have conducted extensive research and have found that a photocurable composition containing a specific combination of monomer species has excellent bending strength and bending modulus after photocuring, as well as excellent bending resistance, tensile strength and elongation, and is particularly suitable for producing artificial nails by stereolithography, thereby completing the present invention.
That is, the specific means for solving the above problems are as follows.

[1] A photocurable composition for use in stereolithography, comprising: (X) at least one di(meth)acrylic monomer having no hydroxyl or carboxyl group in one molecule, two aromatic rings, and two (meth)acryloyloxy groups, and having a weight average molecular weight of 400 or more and 800 or less; (D) at least one (meth)acrylic monomer having at least one ring structure and one (meth)acryloyloxy group in one molecule, and having a weight average molecular weight of 130 or more and 350 or less; and a photopolymerization initiator.
[2] The photocurable composition according to [1], wherein at least one of the di(meth)acrylic monomers constituting the (meth)acrylic monomer (X) has an ether bond in one molecule.
[3] The photocurable composition according to [1] or [2], wherein at least one of the di(meth)acrylic monomers constituting the (meth)acrylic monomer (X) has 1 to 10 ether bonds in one molecule.

[4] The photocurable composition according to any one of [1] to [3], wherein at least one of the di(meth)acrylic monomers constituting the (meth)acrylic monomer (X) is a compound represented by the following general formula (x-1):



[In general formula (x-1), R ^1x , R ^2x , R ^11x , and R ^12x each independently represent a hydrogen atom or a methyl group. R ^3x and R ^4x each independently represent a linear or branched alkylene group having 2 to 4 carbon atoms. mx and nx each independently represent 0 to 10, provided that 1≦(mx+nx)≦10 is satisfied.]

[5] The photocurable composition according to any one of [1] to [4], wherein at least one of the di(meth)acrylic monomers constituting the acrylic monomer (X) is a compound represented by the following general formula (x-2):



[In general formula (x-2), R ^5x , R ^6x , R ^7x , R ^8x , R ^11x , and R ^12x each independently represent a hydrogen atom or a methyl group; mx and nx each independently represent an integer from 0 to 10, provided that 1≦(mx+nx)≦10 is satisfied.]

[6] The photocurable composition according to any one of [1] to [5], wherein at least one of the (meth)acrylic monomers constituting the (meth)acrylic monomer (D) is a compound represented by the following general formula (d-1):



[In general formula (d-1), R ^1d represents a hydrogen atom or a methyl group. R ^2d represents a single bond, or a linear or branched alkylene group having 1 to 5 carbon atoms. R ^3d represents a single bond, an ether bond (-O-), an ester bond (-O-(C=O)-), or -C ₆ H ₄ -O-. ^{A 1d} represents an aromatic ring which may have a substituent. nd represents 1 or 2.]

[7] The photocurable composition according to [6], wherein at least one of the (meth)acrylic monomers constituting the (meth)acrylic monomer (D) is a compound represented by the following general formula (d-2):



[In formula (d-2), R ^1d , R ^4d and R ^5d each independently represent a hydrogen atom or a methyl group. ^{A 2d} represents an aromatic ring which may have a substituent. nd represents 1 or 2.]

[8] The photocurable composition according to any one of [1] to [5], wherein at least one of the (meth)acrylic monomers constituting the (meth)acrylic monomer (D) is a compound represented by the following general formula (d-3):



[In general formula (d-3), R ^6d represents a hydrogen atom or a methyl group, R ^7d represents a single bond or a methylene group, and ^{A 3d} represents at least one ring structure other than an aromatic ring.]

[9] The photocurable composition according to [8], wherein the ring structure other than an aromatic ring is a ring structure having a dicyclopentenyl skeleton, a dicyclopentanyl skeleton, a cyclohexane skeleton, a tetrahydrofuran skeleton, a morpholine skeleton, an isobornyl skeleton, a norbornyl skeleton, a dioxolane skeleton, or a dioxane skeleton.
[10] The photocurable composition according to any one of [1] to [5], wherein at least one of the (meth)acrylic monomers constituting the (meth)acrylic monomer (D) is a (meth)acrylic monomer having at least one ring structure, one hydroxyl group, and one (meth)acryloyloxy group in one molecule.
[11] The photocurable composition according to any one of [1] to [6], wherein the (meth)acrylic monomer (D) is an o-phenylphenol EO-modified acrylate.
[12] The photocurable composition according to any one of [1] to [6], wherein the (meth)acrylic monomer (D) is 3-phenoxybenzyl acrylate.

[13] The photocurable composition according to any one of [1] to [12], wherein the content of the acrylic monomer (X) is 200 parts by mass or more per 1,000 parts by mass of the total content of the (meth)acrylic monomer components.
[14] The photocurable composition according to any one of [1] to [13], wherein the content of the acrylic monomer (D) is 30 parts by mass to 800 parts by mass per 1,000 parts by mass of the total content of the (meth)acrylic monomer components.
[15] The photocurable composition according to any one of [1] to [14], wherein the photopolymerization initiator is at least one selected from the group consisting of alkylphenone compounds and acylphosphine oxide compounds.
[16] The photocurable composition according to any one of [1] to [15], wherein the content of the photopolymerization initiator is 1 part by mass to 50 parts by mass per 1,000 parts by mass of the total content of the (meth)acrylic monomer components.

[17] The photocurable composition according to any one of [1] to [16], having a viscosity of 20 mPa·s to 3,000 mPa·s at 25°C and 50 rpm measured using an E-type viscometer.
[18] The photocurable composition according to any one of <1> to <17>, which is used for producing an artificial nail by stereolithography.
[19] An artificial nail which is a cured product of the photocurable composition according to [18].

Specific aspects of the method for generating modeling data that allows for highly accurate production of an artificial nail, the method for producing an artificial nail, and the system for producing an artificial nail are as follows.
<1> A receiving step of receiving shape information capable of identifying a three-dimensional external shape of an artificial nail to be formed;
a prediction step of predicting, based on predetermined prediction information, a shrinkage state that will occur in a model that has been photo-modeled by a three-dimensional modeling device based on the three-dimensional modeling data and predetermined modeling information and then photo-cured by a curing device under predetermined curing conditions;
a generating step of correcting three-dimensional shape data of the artificial nail to be formed, obtained from the shape information, based on the prediction result of the predicting step, to generate three-dimensional modeling data for optically modeling a model of the artificial nail to be formed by the three-dimensional modeling device;
an output step of outputting the modeling data generated by the generating step;
A method for generating modeling data, comprising:

<2> The method for generating modeling data according to <1>, wherein the prediction information includes modeling information indicating modeling conditions including the three-dimensional modeling device and a photo-modeling material used for photo-modeling in the three-dimensional modeling device, and curing information indicating the curing conditions.
<3> The method for generating modeling data according to <1> or <2>, wherein the prediction information includes shape data of the artificial nail manufactured in advance, modeling data generated from the shape data, and three-dimensional post-curing data indicating an outer shape of a modeled object after curing that has been photo-modeled and photo-cured based on the modeling data.

<4> An acquisition step of acquiring three-dimensional post-curing data indicating an outer shape after curing of a model that has been photo-modeled and photo-cured based on the modeling data;
an updating step of updating the prediction information based on the after-curing data acquired in the acquiring step, shape data of the artificial nail to be formed corresponding to the after-curing data, a prediction result predicted in the predicting step for the shape data, and the modeling data generated based on the prediction result;
A method for generating modeling data according to any one of <1> to <3>,

<5> The method for generating modeling data according to any one of <1> to <4>, further comprising a synthesis step of synthesizing the modeling data of a plurality of the artificial nails to be formed so that the plurality of the artificial nails to be formed are arranged on a substrate and integrally formed by the three-dimensional modeling device.
<6> The method for generating modeling data according to <5>, wherein the synthesizing step includes providing data on the substrate that includes identification information for identifiably specifying each of the plurality of artificial nails to be formed.
<7> The method for generating modeling data according to <5> or <6>, wherein the combining step combines the modeling data so that a plurality of the substrates, each of which has a plurality of the artificial nails to be formed arranged thereon, are photo-modeled in parallel by the three-dimensional modeling device.

<8> A receiving step of receiving shape information capable of identifying a three-dimensional external shape of the artificial nail to be formed;
a prediction step of predicting, based on predetermined prediction information, a shrinkage state that will occur in a model that has been photo-modeled by a three-dimensional modeling device based on the three-dimensional modeling data and predetermined modeling information and then photo-cured by a curing device under predetermined curing conditions;
a generating step of correcting three-dimensional shape data of the artificial nail to be formed, obtained from the shape information, based on the prediction result of the predicting step, to generate three-dimensional modeling data for optically modeling a model of the artificial nail to be formed by the three-dimensional modeling device;
a modeling step of generating a modeled object by the three-dimensional modeling device based on the modeling data generated by the generating step;
a curing step of further photo-curing the object modeled in the modeling step;
A method for producing an artificial nail comprising the steps of:

<9> an acquiring step of acquiring three-dimensional post-curing data indicating an outer shape of the object from the object photo-cured in the curing step;
an evaluation step of evaluating the hardened object by comparing the hardened data with shape data of the artificial nail to be formed;
The method for producing an artificial nail according to <8>, comprising:
<10> The method for producing an artificial nail according to <9>, further comprising: an updating step of updating the prediction information based on an evaluation result of the evaluation step.
<11> The method for manufacturing an artificial nail according to any one of <8> to <10>, further comprising a cleaning step of removing, prior to the curing step, an excess of the photo-molding material used in the photo-molding of the object from the object photo-molded in the modeling step.

<12> A three-dimensional modeling device that optically models a three-dimensional object based on input three-dimensional modeling data;
a curing device that photo-cures the object photo-modeled by the three-dimensional modeling device;
a modeling design device including: a receiving unit that receives shape information capable of identifying a three-dimensional outer shape of the artificial nail to be formed; a prediction unit that predicts, based on predetermined and stored prediction information, a contraction state that will occur in a model that has been photo-modeled by the three-dimensional modeling device based on the three-dimensional modeling data and predetermined modeling information and then photo-cured by the curing device under predetermined curing conditions; a generation unit that corrects the three-dimensional shape data of the artificial nail to be formed obtained from the shape information based on the prediction result of the prediction unit, and generates three-dimensional modeling data for photo-modeling the model of the artificial nail to be formed by the three-dimensional modeling device; and an output unit that outputs the modeling data to the three-dimensional modeling device;
A system for manufacturing an artificial nail comprising:

<13> The artificial nail manufacturing system according to <12>, wherein the prediction information includes the three-dimensional printing device, modeling information indicating modeling conditions including a photo-lithography material used for modeling in the three-dimensional printing device, and curing information indicating the curing conditions.
<14> The artificial nail manufacturing system according to <12> or <13>, wherein the prediction information stored in the modeling design device includes shape data of the artificial nail manufactured in advance, modeling data generated from the shape data, and three-dimensional post-curing data indicating an outer shape of a modeled object after curing that has been photo-modeled based on the modeling data and photo-cured.
<15> The modeling design device,
an acquisition unit that acquires three-dimensional post-curing data indicating an outer shape after curing of a model that has been photo-modeled and photo-cured based on the modeling data;
an update unit that updates the prediction information based on the hardened data acquired by the acquisition unit, shape data of the artificial nail to be formed based on the hardened data, a prediction result predicted by the prediction unit based on the shape data, and the modeling data generated based on the prediction result;
A manufacturing system for an artificial nail according to any one of <12> to <14>,

<16> The modeling design device,
The artificial nail manufacturing system according to any one of <12> to <15>, further comprising a synthesis unit that synthesizes the modeling data of the plurality of artificial nails to be formed so that the plurality of artificial nails to be formed are arranged on a substrate and integrally formed by the three-dimensional modeling device.
<17> The artificial nail manufacturing system according to <16>, wherein the synthesis unit of the shape design device includes data for forming on the substrate identification information that identifiably specifies each of the plurality of artificial nails to be formed.
<18> The artificial nail manufacturing system according to <16> or <17>, wherein the synthesis unit of the modeling design device synthesizes the modeling data so that a plurality of the substrates, each of which has a plurality of the artificial nails to be formed arranged thereon, are modeled in parallel by the three-dimensional modeling device.

<19> The artificial nail manufacturing system according to any one of <12> to <18>, including an evaluation device having an acquisition unit that acquires three-dimensional post-curing data indicating an external shape of the hardened object from the hardened object photo-cured by the curing device, and an evaluation unit that evaluates the hardened object by comparing the post-curing data with shape data of the artificial nail to be formed.
<20> The artificial nail manufacturing system according to <19>, wherein the shape design device includes an update unit that updates the prediction information based on an evaluation result of the evaluation unit of the evaluation device.

As described above, according to one embodiment of the present invention, modeling data that allows for highly accurate production of artificial nails can be obtained. Furthermore, according to one embodiment of the present invention, artificial nails can be produced with high accuracy.

According to one embodiment of the present invention, there is provided a photocurable composition which is used for stereolithography and which, after photocuring, has excellent flexural strength and flexural modulus, as well as excellent flexural resistance and elongation.
According to one embodiment of the present invention, there is provided an artificial nail which is a cured product of the above photocurable composition, and which has excellent flexural strength and flexural modulus, as well as excellent flexural resistance and elongation.

3 is a flow chart showing a manufacturing process of the artificial nail according to the present embodiment. FIG. 2 is a perspective view showing an outline of the artificial nail to be formed and the artificial nail after hardening. 1 is a block diagram showing a configuration of a modeling design system according to an embodiment of the present invention; 1 is a flow chart illustrating a process for manufacturing an artificial nail. FIG. 2 is a perspective view showing an example of a modeled object produced by optical shaping;

In this specification, a numerical range expressed using "to" means a range that includes the numerical values before and after "to" as the lower and upper limits.
In addition, in this specification, an "ether bond" refers to a bond connecting two hydrocarbon groups via an oxygen atom (i.e., a bond represented by -O-), as is normally defined. Therefore, the "-O-" in an ester bond (i.e., -C(=O)-O-) does not fall under the category of an "ether bond".
In this specification, the term "(meth)acrylic monomer" is a concept that encompasses both acrylic monomers and methacrylic monomers.
In this specification, the term "(meth)acrylate" is a concept that encompasses both acrylate and methacrylate.
In this specification, the term "(meth)acryloyloxy group" is a concept that encompasses both an acryloyloxy group and a methacryloyloxy group.

[Photocurable composition]
A photocurable composition according to one embodiment of the present invention is a photocurable composition used for stereolithography, and contains: (X) at least one kind selected from di(meth)acrylic monomers having no hydroxyl group or carboxy group in one molecule, two aromatic rings and two (meth)acryloyloxy groups, and having a weight average molecular weight of 400 or more and 800 or less; (D) at least one kind selected from (meth)acrylic monomers having at least one ring structure and one (meth)acryloyloxy group in one molecule, and having a weight average molecular weight of 130 or more and 350 or less; and a photopolymerization initiator.

The photocurable composition of one embodiment of the present invention contains a combination of the acrylic monomer (X) and the (meth)acrylic monomer (D) and, after photocuring, is excellent in flexural strength and flexural modulus, and further, is excellent in flexural resistance and elongation.
Therefore, a photo-molded object, preferably an artificial nail, produced by photo-molding using the photo-curable composition of this embodiment has excellent bending strength and bending modulus, and also has excellent bending resistance and elongation. Furthermore, the photo-curable composition of this embodiment has a viscosity suitable for producing an artificial nail or the like by photo-molding (i.e., an example of a preferred form of a photo-molded object, the same applies below), and after photo-curing, the bending strength, bending modulus, bending resistance, tensile strength and elongation are within the range suitable for an artificial nail. In other words, the photo-curable composition of this embodiment can be a photo-curable artificial nail composition.

In this specification, the term "(meth)acrylic monomer component" refers to all (meth)acrylic monomers contained in the photocurable composition.
The "(meth)acrylic monomer component" includes at least the (meth)acrylic monomer (X) and the (meth)acrylic monomer (D).
The "(meth)acrylic monomer component" may contain other (meth)acrylic monomers.

In the photocurable composition of this embodiment, the inclusion of (meth)acrylic monomer (X) improves the bending strength and bending modulus after photocuring, compared to a case in which a (meth)acrylic monomer having no hydroxyl group or carboxy group in one molecule and one aromatic ring and one (meth)acryloyloxy group is included instead of (meth)acrylic monomer (X).

In the photocurable composition of this embodiment, by including (meth)acrylic monomer (X), the phenomenon of the monomer becoming too crystalline is suppressed and the viscosity of the photocurable composition is reduced, compared to when a di(meth)acrylic monomer having no hydroxyl group or carboxy group in one molecule and one aromatic ring and two (meth)acryloyloxy groups is included instead of (meth)acrylic monomer (X).

In the photocurable composition of this embodiment, the (meth)acrylic monomer (X) is contained, and thus the viscosity of the photocurable composition is reduced compared to the case where a (meth)acrylic monomer having no hydroxyl group or carboxy group and three or more aromatic rings in one molecule is used instead of the (meth)acrylic monomer (X).

In the photocurable composition, the inclusion of (meth)acrylic monomer (X) improves the bending resistance, tensile strength, and elongation percentage after photocuring, compared to a case where a (meth)acrylic monomer having no hydroxyl group or carboxy group and three or more (meth)acryloyloxy groups in one molecule is used instead of (meth)acrylic monomer (X).

The upper limit of the weight average molecular weight of the (meth)acrylic monomer (X), 800, is set from the viewpoint of the bending strength and bending modulus after photocuring.
The lower limit of the weight average molecular weight of the (meth)acrylic monomer (X), 400, is a lower limit set from the viewpoint of ease of production or availability of the monomer.

Furthermore, in the photocurable composition of the present embodiment, the inclusion of the (meth)acrylic monomer (D) improves the bending resistance after photocuring. In addition, the inclusion of the (meth)acrylic monomer (D) provides a well-balanced and excellent bending strength, bending modulus, bending resistance, tensile strength, and elongation after photocuring.
Although the reason is not clear, it is considered that the (meth)acrylic monomer (D) has at least one ring structure, which strengthens the intermolecular force between the ring structure of the (meth)acrylic monomer (X) and the ring structure of the (meth)acrylic monomer (D) and between the ring structures of the (meth)acrylic monomer (D), thereby improving the bending resistance.
The upper limit of the weight average molecular weight of the (meth)acrylic monomer (D) is 350, which is an upper limit set from the viewpoint of the bending strength and bending modulus after photocuring.
The lower limit of the weight average molecular weight of the (meth)acrylic monomer (D), 130, is a lower limit set from the viewpoint of ease of production or availability of the monomer.

From the viewpoint of practicality of the resulting artificial nail and the like, the photocurable composition of this embodiment preferably satisfies the following flexural strength (flexural strength) and flexural modulus after photocuring.
That is, the photocurable composition of this embodiment is shaped into a shape measuring 80 mm × 10 mm × 4 mm thick, and the resulting shape is irradiated with ultraviolet light at 5 J/ ^cm2 to photocure it into a photomolded object (i.e., a cured product; the same applies below). When the flexural strength (flexural strength) is measured in accordance with ISO178 (or JIS K7171), it is preferable that this flexural strength (flexural strength) be 10 MPa or more, more preferably 40 MPa or more, and even more preferably 60 MPa or more.
Furthermore, the photocurable composition of this embodiment is shaped into a structure measuring 80 mm × 10 mm × 4 mm thick, and the resulting structure is irradiated with ultraviolet light at 5 J/ ^cm2 to photocure it into a photopolymerized object. When the flexural modulus is measured in accordance with ISO 178 (or JIS K7171), the flexural modulus is preferably 400 MPa or more, more preferably 1500 MPa or more, and even more preferably 2000 MPa or more.

From the viewpoint of practicality of the resulting artificial nail and the like, the photocurable composition of this embodiment preferably satisfies the following bending resistance after photocuring.
That is, the photocurable resin composition is shaped using a 3D printer to have an outer diameter of 8 mm, an inner diameter of 7.5 mm (thickness of 0.5 mm), a circumference of 90°, and a length of 15 mm, and then irradiated with ultraviolet light of 365 nm wavelength at 5 J/ ^cm2 to fully cure the composition to produce a photo-modeled object. Five of the resulting objects are placed one under a metal cube of 50 mm length, 50 mm width, and 50 mm height, and a load of 20 kg is applied from above. When the object is visually inspected to see if it has cracked, it is preferable that the five objects retain their shape without cracking.

Furthermore, the photocurable resin composition of this embodiment is shaped using a 3D printer to have an outer diameter of 8 mm, an inner diameter of 7 mm (thickness of 1.0 mm), a circumference of 90°, and a length of 15 mm, and is then fully cured by irradiating it with ultraviolet light having a wavelength of 365 nm at 5 J/ ^cm2 to form a photo-molded object. Five of the resulting objects are placed under a metal cube having a length of 50 mm, a width of 50 mm, and a height of 50 mm, and a load of 20 kg is applied from above. When the object is visually inspected to see if it has cracked, it is preferable that the five objects retain their shape without cracking.

From the viewpoint of practicality of the resulting artificial nail and the like, the photocurable composition of this embodiment preferably satisfies the following tensile strength and elongation after photocuring.
That is, the photocurable resin composition is shaped to a size of 30 mm x 10 mm x 0.5 mm thick using a 3D printer, and then irradiated with ultraviolet light having a wavelength of 365 nm at 5 J/cm ² to effect main curing to produce a photo-modeled object, and the resulting object (i.e., a tensile test piece) is measured using a tensile tester under conditions of a chuck distance of 20 mm and a tensile speed of 5 mm/min, and the tensile strength at the time the tensile test piece breaks is preferably 15 MPa or more, and more preferably 40 MPa or more. In addition, the elongation at the time the tensile test piece breaks is preferably 10% or more, and more preferably 20% or more.

The glass transition temperature (Tg) of the photocurable composition of this embodiment after photocuring is not particularly limited, but from the viewpoint of the balance of flexural strength, flexural modulus, flexural resistance, tensile strength, and elongation, the glass transition temperature (Tg) after photocuring is preferably 20 to 100°C, and more preferably 40 to 80°C.

In this embodiment, "stereolithography" is one of the three-dimensional modeling methods using a 3D printer.
Examples of photolithography methods include a stereo lithography apparatus (SLA) method, a digital light processing (DLP) method, and an inkjet method.
The photocurable composition of this embodiment is particularly suitable for stereolithography by the SLA method or DLP method.

In one embodiment of the present invention, "photo-fabrication" refers to the fabrication of a three-dimensional image using a photo-fabrication material (manufacturing a model). In addition, in this embodiment, "photo-curing" refers to further curing a model obtained by photo-fabrication with light.
The stereolithography in this embodiment is one type of three-dimensional modeling method using a three-dimensional modeling device (hereinafter, referred to as a 3D printer). Specific stereolithography methods include a stereolithography apparatus (SLA) method, a digital light processing (DLP) method, and an inkjet method.

The SLA method includes a method in which a photocurable composition is irradiated with spot-shaped ultraviolet laser light to obtain a three-dimensional object.
When producing an artificial nail or the like by the SLA method, for example, a liquid photocurable composition is stored in a container, and the liquid surface of the liquid photocurable composition is selectively irradiated with spot-like ultraviolet laser light so as to obtain a desired pattern, thereby curing the photocurable composition and forming a cured layer of a desired thickness on a modeling table, and then the modeling table is moved (i.e., raised or lowered), and one layer of liquid photocurable composition is supplied on top of the cured layer, which is similarly cured, and the lamination operation is repeated to obtain successive cured layers.

The DLP method includes a method of obtaining a three-dimensional object by irradiating a photocurable composition with planar light. For a method of obtaining a three-dimensional object by the DLP method, for example, the descriptions in Japanese Patent No. 5111880 and Japanese Patent No. 5235056 can be appropriately referred to.
When producing a molded object such as an artificial nail or a dental prosthesis by the DLP method, for example, a lamp that emits light other than laser light, such as a high-pressure mercury lamp, an ultra-high-pressure mercury lamp, or a low-pressure mercury lamp, or an LED, is used as a light source, and a planar drawing mask having a plurality of digital micromirror shutters arranged in a planar manner is placed between the light source and the molded surface of the photocurable composition, and light is irradiated through the planar drawing mask to the molded surface of the photocurable composition to sequentially laminate cured layers having a predetermined shape pattern.

An example of the inkjet method is a method in which droplets of a photocurable composition are continuously discharged from an inkjet nozzle onto a substrate, and the droplets attached to the substrate are irradiated with light to obtain a three-dimensional object.
When producing an artificial nail or the like by the inkjet method, for example, a photocurable composition is ejected from the inkjet nozzle onto a substrate while a head equipped with an inkjet nozzle and a light source is scanned within a plane, and the ejected photocurable composition is irradiated with light to form a cured layer, and these operations are repeated to sequentially stack the cured layers.

From the viewpoint of suitability for producing artificial nails and the like by photolithography, the photocurable composition of this embodiment has a viscosity measured at 25°C and 50 rpm using an E-type viscometer of preferably 20 mPa·s to 3000 mPa·s, more preferably 20 mPa·s to 1500 mPa·s, and particularly preferably 20 to 1200 mPa·s. The lower limit of the viscosity range is more preferably 30 mPa·s, and particularly preferably 40 mPa·s.

The viscosity of the photocurable composition at 25° C. and 50 rpm may be adjusted depending on the type of stereolithography.
For example, when artificial nails or the like are produced by the SLA method, the viscosity is preferably 20 mPa·s to 3000 mPa·s, more preferably 20 mPa·s to 1500 mPa·s, and particularly preferably 30 mPa·s to 1200 mPa·s.
For example, when artificial nails or the like are produced by the DLP method, the viscosity is preferably 50 mPa·s to 500 mPa·s, and more preferably 50 mPa·s to 250 mPa·s.
For example, when artificial nails or the like are produced by an inkjet method, the viscosity is preferably from 20 mPa·s to 500 mPa·s, and more preferably from 20 mPa·s to 100 mPa·s.

Next, the components of the photocurable composition of this embodiment will be described.

<(Meth)acrylic monomer (X)>
The (meth)acrylic monomer component in the photocurable composition of this embodiment includes a (meth)acrylic monomer (X).
The (meth)acrylic monomer (X) is at least one selected from di(meth)acrylic monomers having no hydroxyl group or carboxy group in one molecule, and having two aromatic rings and two (meth)acryloyloxy groups, and has a weight average molecular weight of 400 or more and 800 or less.
In the photocurable composition of this embodiment, the (meth)acrylic monomer (X) mainly contributes to improving the flexural strength and flexural modulus after photocuring.

The (meth)acrylic monomer (X) may be a di(meth)acrylic monomer having no hydroxyl or carboxyl groups in one molecule and two aromatic rings and two (meth)acryloyloxy groups, or may be a mixture of two or more di(meth)acrylic monomers.

At least one of the di(meth)acrylic monomers constituting the (meth)acrylic monomer (X) preferably has an ether bond in one molecule, from the viewpoint of further improving the fracture toughness after photocuring.
In detail, at least one of the di(meth)acrylic monomers constituting the (meth)acrylic monomer (X) has an ether bond in one molecule, which increases the degree of freedom of molecular motion and imparts flexibility to the cured product after photocuring, thereby improving toughness, and as a result, the fracture toughness of the cured product (i.e., the fracture toughness of the photocurable composition after photocuring) is improved.

At least one of the di(meth)acrylic monomers more preferably has 1 to 10 ether bonds in one molecule.
When at least one of the di(meth)acrylic monomers has 10 or less ether bonds in one molecule, the flexural strength and flexural modulus after photocuring are further improved.
From the viewpoint of further improving the bending strength and bending modulus after photocuring, the number of ether bonds in one molecule is more preferably from 2 to 6, and particularly preferably from 2 to 4.

At least one of the di(meth)acrylic monomers is more preferably a compound represented by the following general formula (x-1), from the viewpoint of reducing the viscosity of the photocurable composition and further improving the fracture toughness, bending strength, and bending modulus after photocuring.

In the general formula (x-1), R ^1x , R ^2x , R ^11x , and R ^12x each independently represent a hydrogen atom or a methyl group. R ^3x and R ^4x each independently represent a linear or branched alkylene group having 2 to 4 carbon atoms. mx and nx each independently represent 0 to 10, provided that 1≦(mx+nx)≦10 is satisfied.

When a plurality of R ^3x are present in the general formula (x-1), the plurality of R ^3x may be the same or different. The same applies to R ^4x .

In the general formula (x-1), R ^1x and R ^2x are preferably methyl groups.
Furthermore, R ^3x and R ^4x each independently preferably represent an ethylene group, a trimethylene group, a tetramethylene group, a 1-methylethylene group, a 1-ethylethylene group, or a 2-methyltrimethylene group, and more preferably an ethylene group or a 1-methylethylene group.
Furthermore, both of R ^3x and R ^4x are preferably an ethylene group, a trimethylene group, a tetramethylene group, a 1-methylethylene group or a 2-methyltrimethylene group, and more preferably an ethylene group or a 1-methylethylene group.
Furthermore, mx+nx is from 1 to 10, and is particularly preferably from 2 to 6 from the viewpoint of further improving the bending strength and bending modulus after photocuring.

At least one of the di(meth)acrylic monomers constituting the (meth)acrylic monomer (X) is more preferably a compound represented by the following general formula (x-2), from the viewpoint of reducing the viscosity of the photocurable composition and further improving the fracture toughness, flexural strength, and flexural modulus after photocuring.

In formula (x-2), R ^5x , R ^6x , R ^7x , R ^8x , R ^11x and R ^12x each independently represent a hydrogen atom or a methyl group, and mx and nx each independently represent an integer from 0 to 10, provided that 1≦(mx+nx)≦10 is satisfied.

When a plurality of R ^5x are present in general formula (x-2), the plurality of R ^5x may be the same or different. The same applies to each of R ^6x , R ^7x , and R ^8x .

In general formula (x-2), it is preferred that one of R ^5x and R ^6x is a methyl group and the other is a hydrogen atom, and that one of R ^7x and R ^8x is a methyl group and the other is a hydrogen atom.
In general formula (x-2), it is particularly preferable that R ^5x and R ^8x are both methyl groups, and R ^6x and R ^7x are both hydrogen atoms.

In addition, mx+nx is 1 to 10, but from the viewpoint of further improving the bending strength and bending modulus after photocuring, it is particularly preferable that it is 2 to 6.

Specific examples of the (meth)acrylic monomer (X) include ethoxylated bisphenol A di(meth)acrylate (EO=2 mol, 2.2 mol, 2.6 mol, 3 mol, 4 mol, or 10 mol), propoxylated bisphenol A di(meth)acrylate (PO=2 mol, 3 mol, 4 mol, or 8 mol), and ethoxylated bisphenol F di(meth)acrylate (EO=2 mol, 2.2 mol, 2.6 mol, 3 mol, 4 mol, or 10 mol).
As examples, the structural formulae of ethoxylated bisphenol A di(meth)acrylate and ethoxylated bisphenol A dimethacrylate are shown below.

In the photocurable composition of this embodiment, the content of the (meth)acrylic monomer (X) is, from the viewpoint of reducing the viscosity of the composition and improving the flexural strength and flexural modulus after photocuring, preferably 200 parts by mass or more, more preferably 300 parts by mass or more, even more preferably 400 parts by mass or more, even more preferably 500 parts by mass or more, and even more preferably 550 parts by mass or more, per 1000 parts by mass of the total content of the (meth)acrylic monomer components.
In addition, the content of the (meth)acrylic monomer (X) is not particularly limited as long as it is less than 1000 parts by mass relative to 1000 parts by mass of the total content of the (meth)acrylic monomer components. From the viewpoint of fracture toughness after photocuring, however, it is preferably 950 parts by mass or less, more preferably 900 parts by mass or less, and even more preferably 850 parts by mass or less.

<(Meth)acrylic monomer (D)>
The photocurable composition of this embodiment contains a (meth)acrylic monomer (D).
The (meth)acrylic monomer (D) is at least one selected from (meth)acrylic monomers having at least one ring structure and one (meth)acryloyloxy group in one molecule, and has a weight average molecular weight of 130 or more and 350 or less.
When the (meth)acrylic monomer component contains the (meth)acrylic monomer (D), the bending resistance after photocuring is significantly improved.
The (meth)acrylic monomer (D) may consist of only one type of (meth)acrylic monomer having at least one ring structure and one (meth)acryloyloxy group in one molecule, or may be a mixture of two or more types of the (meth)acrylic monomers.

From the viewpoint of further improving bending resistance after photocuring, it is preferable that at least one of the (meth)acrylic monomers constituting (D) is a compound represented by the following general formula (d-1):

In general formula (d-1), R ^1d represents a hydrogen atom or a methyl group. R ^2d represents a single bond, or a linear or branched alkylene group having 1 to 5 carbon atoms. R ^3d represents a single bond, an ether bond (-O-), an ester bond (-O-(C=O)-), or -C ₆ H ₄ -O-. ^{A 1d} represents an aromatic ring which may have a substituent. nd represents 1 or 2. In addition, general formula (d-1) preferably contains 1 or 2 ether bonds or ester bonds (excluding those contained in an acryloyloxy group).

Examples of the substituent on the aromatic ring in A ^1d include an alkyl group (for example, a methyl group, an ethyl group, a propyl group, or a butyl group), an aryl group, an alkylaryl group, and an aryloxy group.
Examples of the aromatic ring in A ^1d which may have a substituent include a phenyl group, a phenyl ether group, a biphenyl group, a terpenyl group, a benzhydryl group, a diphenylamino group, a benzophenone group, a naphthyl group, an anthracenyl group, a phenanthrenyl group, a tolyl group, a xylyl group, a mesityl group, a cumyl group, a styryl group, and a nonylphenyl group.
The aromatic ring in A ^1d is preferably a phenyl group, a phenyl ether group, a biphenyl group, a naphthyl group, a cumyl group or a nonylphenyl group.

Examples of the linear or branched alkylene group having 1 to 5 carbon atoms for R ^2d include a methylene group, an ethylene group, an n-propylene group, an isopropylene group, an n-butylene group, an isobutylene group, a sec-butylene group, a tert-butylene group, an n-pentylene group, an isopentylene group, a neopentylene group, a sec-pentylene group, a tert-pentylene group, and a 3-pentylene group. ^{R 2d} is preferably a single bond, a methylene group, or an ethylene group.
R ^3d is preferably an ether bond or an ester bond.

Specific examples of the (meth)acrylic monomer represented by general formula (d-1) include, for example, phenoxyethylene glycol (meth)acrylate, 3-phenoxybenzyl (meth)acrylate, o-phenylphenol EO-modified (meth)acrylate, o-phenylphenol (meth)acrylate, p-cumylphenol (meth)acrylate, p-nonylphenol (meth)acrylate, p-methylphenol (meth)acrylate, neopentyl glycol-(meth)acrylic acid-benzoic acid ester, benzyl (meth)acrylate, acrylate, phenyl (meth)acrylate, phenyl glycidyl ether (meth)acrylic acid adduct, phenoxyethylene glycol (meth)acrylate, phenoxydiethylene glycol (meth)acrylate, neopentyl glycol (meth)acrylic acid benzoate, naphthoxy EO-modified (meth)acrylate, 2-hydroxyethyl methacrylate, EO-modified p-cumylphenol (meth)acrylate, or nonylphenol EO-modified (meth)acrylate (preferably, EO=1 to 2 mol).
Among these, the (meth)acrylic monomer represented by general formula (d-1) is particularly preferably o-phenylphenol EO-modified (meth)acrylate or 3-phenoxybenzyl (meth)acrylate, where "EO-modified" means having an ethylene oxide unit (i.e., -CH ₂ -CH ₂ -O-) structure.
The structural formulae of phenoxyethylene glycol (meth)acrylate, 3-phenoxybenzyl (meth)acrylate, o-phenylphenol EO-modified (meth)acrylate (EO=1 mol), phenyl glycidyl ether (meth)acrylic acid adduct, and 2-hydroxyethyl methacrylate are shown below.

From the viewpoint of further improving the bending resistance, tensile strength, and elongation percentage after photocuring, it is more preferable that at least one of the (meth)acrylic monomers constituting (D) is a compound represented by the following general formula (d-2).

In general formula (d-2), R ^1d , R ^4d and R ^5d each independently represent a hydrogen atom or a methyl group. ^{A 2d} represents at least one aromatic ring which may have a substituent. nd represents 1 to 2. Examples of the aromatic ring in A ^2d and preferred examples of the aromatic ring are the same as those exemplified for A ^1d .

When a plurality of R ^4d are present in general formula (d-2), the plurality of R ^4d may be the same or different. The same applies to R ^5d .
The weight average molecular weight of the (meth)acrylic monomer (D) is 130 or more and 350 or less, preferably 150 or more and 300 or less, and more preferably 150 or more and 280 or less.

From the viewpoint of further improving the bending resistance and elongation percentage after photocuring, it is also preferable that at least one of the (meth)acrylic monomers constituting the (meth)acrylic monomer (D) is a compound represented by the following general formula (d-3).

In formula (d-3), R ^6d represents a hydrogen atom or a methyl group, R ^7d represents a single bond or a methylene group, and ^{A 3d} represents at least one ring structure other than an aromatic ring.
The ring structure other than the aromatic ring is not particularly limited, and may be a monocyclic structure or a polycyclic structure. The number of ring members of the ring structure other than the aromatic ring is not limited, but a 5- to 12-membered ring is preferable. In addition, the ring structure other than the aromatic ring is preferably an alicyclic structure or a heterocyclic structure. Examples of heteroatoms in the heterocyclic structure include O, S and/or N.

Examples of ring structures other than aromatic rings include a dicyclopentenyl skeleton, a dicyclopentanyl skeleton, a cyclohexane skeleton, a tetrahydrofuran skeleton, a morpholine skeleton, an isobornyl skeleton, a norbornyl skeleton, a dioxolane skeleton or a dioxane skeleton, a cyclopropane skeleton, a cyclobutane skeleton, a cyclopentane skeleton, a cycloheptane skeleton, a cyclooctane skeleton, a cyclopropene skeleton, a cyclobutene skeleton, a cyclopentene skeleton, a cyclohexene skeleton, a cycloheptene skeleton, a cyclooctene skeleton, and a cyclohexadiene skeleton. skeleton, cyclooctadiene skeleton, norbornene skeleton, norbornadiene skeleton, norbornane skeleton, ethyleneimine skeleton, ethylene oxide skeleton, ethylene sulfide skeleton, azacyclobutane skeleton, oxetane skeleton, thietane skeleton, pyrrolidine skeleton, imidazolidine skeleton, pyrazolidine skeleton, tetrahydrothiophene skeleton, piperidine skeleton, piperazine skeleton, tetrahydropyran skeleton, tetrahydrothiopyran skeleton, azepane skeleton, oxepane skeleton, thiepane skeleton, or imidazoline skeleton.

In addition, at least one of the (meth)acrylic monomers represented by general formula (d-3) is preferably a compound not containing an imide structure, from the viewpoint of suppressing water absorption.
That is, from the viewpoint of further improving the bending strength and bending modulus after photocuring, the (meth)acrylic monomer represented by general formula (d-3) is more preferably a compound represented by the following general formula (d-4):

In general formula (d-4), R ^6d represents a hydrogen atom or a methyl group, R ^7d represents a single bond or a methylene group, and ^{A 4d} represents a ring structure having a dicyclopentenyl skeleton, a dicyclopentanyl skeleton, a cyclohexane skeleton, a tetrahydrofuran skeleton, a morpholine skeleton, an isobornyl skeleton, a norbornyl skeleton, a dioxolane skeleton, or a dioxane skeleton.
In general formula (d-4), the ring structure represented by A ^4d may have a substituent such as an alkyl group (eg, a methyl group, an ethyl group, a propyl group, a butyl group, etc.).

The weight average molecular weight of the (meth)acrylic monomer represented by general formula (d-4) is 130 or more and 350 or less, preferably 150 or more and 240 or less, and more preferably 180 or more and 230 or less.

Examples of the (meth)acrylic monomer represented by general formula (d-4) include isobornyl (meth)acrylate, norbornyl (meth)acrylate, dicyclopentenyl (meth)acrylate, dicyclopentanyl (meth)acrylate, cyclohexyl (meth)acrylate, tetrahydrofurfuryl (meth)acrylate, (meth)acryloylmorpholine, 4-tert-butylcyclohexanol (meth)acrylate, cyclohexanedimethanol di(meth)acrylate, (2-methyl-2-ethyl-1,3-dioxolan-4-yl)methyl acrylate, cyclic trimethylolpropane formal acrylate, and the like.

In the photocurable composition of this embodiment, the content of the (meth)acrylic monomer (D) is preferably 30 parts by mass to 800 parts by mass, and more preferably 50 parts by mass to 700 parts by mass, per 1000 parts by mass of the total content of the (meth)acrylic monomer components.

The (meth)acrylic monomer component in the photocurable composition of this embodiment may contain at least one other (meth)acrylic monomer than the above-mentioned (meth)acrylic monomer (X) and (meth)acrylic monomer (D), as long as the effects of the invention are achieved.
However, the total content of the (meth)acrylic monomer (X) and the (meth)acrylic monomer (D) in the (meth)acrylic monomer component is preferably 60% by mass or more, more preferably 80% by mass or more, and even more preferably 90% by mass or more, based on the total amount of the (meth)acrylic monomer component. This total content may be 100% by mass based on the total amount of the (meth)acrylic monomer component.

<Photopolymerization initiator>
The photocurable composition of this embodiment contains a photopolymerization initiator.
The photopolymerization initiator is not particularly limited as long as it generates radicals when irradiated with light, but it is preferable that the photopolymerization initiator generates radicals at the wavelength of light used in stereolithography.
The wavelength of light used in stereolithography is generally 365 nm to 500 nm, but in practice, it is preferably 365 nm to 430 nm, and more preferably 365 nm to 420 nm.

Examples of photopolymerization initiators that generate radicals at the wavelength of light used in stereolithography include alkylphenone compounds, acylphosphine oxide compounds, titanocene compounds, oxime ester compounds, benzoin compounds, acetophenone compounds, benzophenone compounds, thioxanthone compounds, α-acyloxime ester compounds, phenylglyoxylate compounds, benzyl compounds, azo compounds, diphenyl sulfide compounds, organic dye compounds, iron-phthalocyanine compounds, benzoin ether compounds, and anthraquinone compounds.
Among these, from the viewpoint of reactivity and the like, alkylphenone compounds and acylphosphine oxide compounds are preferred.

An example of the alkylphenone compound is 1-hydroxy-cyclohexyl-phenyl-ketone (Irgacure 184: manufactured by BASF).
Examples of the acylphosphine oxide compound include bis(2,4,6-trimethylbenzoyl)-phenylphosphine oxide (Irgacure 819: manufactured by BASF Corporation), 2,4,6-trimethylbenzoyl-diphenyl-phosphine oxide (Irgacure TPO: manufactured by BASF Corporation), and the like.
The structural formulae of bis(2,4,6-trimethylbenzoyl)-phenylphosphine oxide (Irgacure 819: manufactured by BASF Corporation) and 2,4,6-trimethylbenzoyl-diphenyl-phosphine oxide (Irgacure TPO: manufactured by BASF Corporation) are shown below.

The photocurable composition of this embodiment may contain only one type of photopolymerization initiator, or may contain two or more types of photopolymerization initiators.
The content of the photopolymerization initiator in the photocurable composition of this embodiment (the total content when two or more types are used) is preferably 1 part by mass to 50 parts by mass, more preferably 2 parts by mass to 30 parts by mass, and even more preferably 3 parts by mass to 25 parts by mass, relative to 1000 parts by mass of the total content of the (meth)acrylic monomer components.

<Other ingredients>
The photocurable composition of this embodiment may contain at least one other component other than the (meth)acrylic monomer component and the photopolymerization initiator, as necessary.
However, the total content of the (meth)acrylic monomer component and the photopolymerization initiator is preferably 60 mass % or more, more preferably 80 mass % or more, and even more preferably 90 mass % or more, based on the total amount of the photocurable composition.

The other components include coloring materials.
For example, when the photocurable composition of this embodiment is used to prepare an artificial nail, the photocurable composition may contain a coloring material to color it to a desired color tone from the viewpoint of aesthetics.
Examples of the coloring material include pigments, dyes, coloring materials, etc. More specifically, examples of the coloring material include synthetic tar coloring materials, aluminum lakes of synthetic tar coloring materials, inorganic pigments, and natural coloring materials.

Other components include other curable resins other than the above (meth)acrylic monomer components (for example, other curable monomers other than the above (meth)acrylic monomer components, etc.).

Other components include a thermal polymerization initiator.
When the photocurable composition of the present embodiment contains a thermal polymerization initiator, photocuring and thermal curing can be performed in combination. Examples of the thermal polymerization initiator include a thermal radical generator and an amine compound.

Other components include additives such as coupling agents such as silane coupling agents (e.g., 3-acryloxypropyltrimethoxysilane), rubber agents, ion trapping agents, ion exchange agents, leveling agents, plasticizers, and defoamers.

The method for preparing the photocurable composition of this embodiment is not particularly limited, and examples thereof include a method of mixing the acrylic monomer (X), the (meth)acrylic monomer (D), and the photopolymerization initiator (and other components as necessary).
The means for mixing the components is not particularly limited, and examples thereof include ultrasonic dissolution, a twin-arm mixer, a roll mixer, a twin-screw extruder, a ball mill mixer, and a planetary mixer.
The photocurable composition of this embodiment may be prepared by mixing the components, filtering the mixture through a filter to remove impurities, and then subjecting the mixture to a vacuum degassing treatment.

[Photocured product]
When photocuring is performed using the photocurable composition of the present embodiment, there is no particular limitation, and any of the known methods and devices can be used. For example, a method of laminating multiple cured layers by repeating a process of forming a thin film made of the photocurable composition of the present embodiment and a process of irradiating the thin film with light to obtain a cured layer multiple times to produce a photocured product of a desired shape can be mentioned. The obtained photocured product may be used as it is, or may be used after further performing post-cure by light irradiation, heating, etc. to improve its mechanical properties, shape stability, etc.

[Artificial nails]
As the cured product (i.e., photo-modeled product) of the photocurable composition of this embodiment, an artificial nail is particularly preferred. The artificial nail, which is the cured product of the photocurable composition of this embodiment, has excellent bending strength, bending modulus, bending resistance, tensile strength, and elongation.
The size of the artificial nail of this embodiment is not particularly limited, and an artificial nail of a desired size can be manufactured. The artificial nail of this embodiment may be a set.
Moreover, the artificial nail of the present embodiment may be produced either partially using the photocurable composition of the present embodiment or entirely using the photocurable composition of the present embodiment.

An example of an embodiment of the present invention will be described in detail below with reference to the drawings. In the following description, an "apparatus" (i.e., a device) may be any device having a predetermined function, and may exist as an independent device or as a part of a device having other functions. For example, a three-dimensional modeling device, a curing device, a photocuring device, a modeling design device, a three-dimensional shape measuring device, and an evaluation device may exist in any form as long as they have the functions described in the respective descriptions. For example, a photocuring device may be a device having a light irradiation function incorporated in a 3D printer, or may be a device independent of the 3D printer.
1 shows an outline of the manufacturing process of the artificial nail according to the present embodiment. The manufacturing process of the artificial nail according to the present embodiment includes a shape acquisition process 80 as a receiving section, a design process 82 as a design section, a modeling process 84 as a modeling section, a cleaning process 86, and a hardening process 88 as a hardening section. The artificial nail is manufactured as a plain artificial nail without decoration or the like through the shape acquisition process 80, the design process 82, the modeling process 84, the cleaning process 86, and the hardening process 88. In the present embodiment, the cleaning process 86 may be included in the modeling process 84 as a post-processing of the modeling process 84, or the cleaning process 86 may be included in the hardening process 88 as a pre-processing of the hardening process 88.

In this embodiment, a rapid prototype method is applied to create a three-dimensional image (i.e., a three-dimensional model, hereinafter also referred to as a molded object) of an artificial nail based on three-dimensional data (hereinafter also referred to as molding data). As a molding method, any of the following may be applied: binder jetting, directed energy volumetric imaging, material extraction, material jetting, powder bed fusion, sheet lamination, liquid vat photopolymerization, as well as additive manufacturing, photolithography, powder modeling, fused deposition modeling, and inkjet printing.

In the modeling process 84 according to this embodiment, a photocurable composition is used as the photo-modeling material, and a model to be an artificial nail is produced by photo-modeling. The method of photo-modeling and the viscosity of the photocurable composition are as described above.

In the modeling process 84 according to this embodiment, a 3D printer using any of the SLA method, DLP method, and inkjet method is used, and the 3D printer operates based on three-dimensional data (hereinafter, modeling data) to manufacture a model. Note that the 3D printer may use a method other than the SLA method, DLP method, and inkjet method.

In the cleaning process 86, excess photocurable composition is washed off and removed from the object produced by stereolithography using the photocurable composition in the modeling process 84. In other words, uncured photocurable composition adhering to the object is removed.

In the curing step 88 according to this embodiment, the photocurable composition is further photocured to finish the artificial nail. In the curing step 88, the shaped object is photocured based on preset photocuring conditions. The curing conditions include designation of a photocuring device and designation of operating conditions of the photocuring device. In the curing step 88, the artificial nail is manufactured by photocuring the shaped object using the photocuring device designated in the curing conditions and based on the operating conditions set in the curing conditions.
In this embodiment, the light (e.g., laser light) used for photo-modeling and photo-curing can be light of any wavelength, but light of a wavelength that can provide relatively high light energy is preferable, and for example, a wavelength of 320 nm to 420 nm is more preferable. This can improve the energy efficiency during photo-modeling and photo-curing, and photo-modeling and photo-curing can be performed effectively.

The shape acquisition process 80 receives shape information related to the shape and dimensions of the artificial nail to be formed. The shape information related to the shape and dimensions of the artificial nail to be formed preferably includes information that can specify the three-dimensional shape of the artificial nail to be formed, including the external shape, length, width, thickness, degree of warping in the length direction (i.e., curvature), and degree of warping in the width direction. Such shape information of the artificial nail applies information that includes at least three-dimensional data indicating the shape of the surface (hereinafter referred to as the back surface of the artificial nail) that contacts the surface of the human nail (hereinafter referred to as the bare nail), and the thickness at each position of the back surface of the artificial nail to be formed. In other words, the shape information of the artificial nail includes three-dimensional data (hereinafter referred to as shape data) that can specify the three-dimensional shape (i.e., external shape) of the artificial nail to be formed, or data that can generate shape data. Note that the back surface of the artificial nail includes a surface that is outside the bare nail (for example, a surface that protrudes from the tip of the nail, etc.).

The shape acquisition process 80 may not only receive shape information regarding the shape and dimensions of the artificial nail to be formed, but may also read and acquire shape information regarding the shape and dimensions of the artificial nail to be formed using a three-dimensional shape measuring device (i.e., a 3D scanner).
The shape information of the artificial nail acquired in the shape acquisition step 80 preferably includes information identifying the client and the target of the artificial nail to be formed. That is, the shape information of the artificial nail to be formed preferably includes information identifying whose fingernail the artificial nail is intended to be attached to or the customer who requested the formation of the artificial nail (e.g., customer information). In addition, the shape information preferably includes at least information indicating which finger or toe the artificial nail is to be attached to, and information indicating which of the first finger (i.e., thumb), second finger (i.e., index finger), third finger (i.e., middle finger), fourth finger (i.e., ring finger), and fifth finger (i.e., little finger) the artificial nail is to be attached to (i.e., target information).

In the shape acquisition step 80, information specifying the client and the person on whom the artificial nail is to be formed is input, and the input information is accepted as shape information of the artificial nail.
Furthermore, the shape information acquired in the shape acquisition process 80 may include a photo-lithography material used for photo-lithography of the artificial nail (e.g., a photocurable composition or a component contained in the photocurable composition), a designation of a 3D printer used for photo-lithography, and a designation of curing conditions. In this case, in the shape acquisition process 80, a designation of a photo-lithography material, a designation of a 3D printer, and a designation of curing conditions are input, and the input designation is accepted as shape information of the artificial nail.

In the design process 82, three-dimensional shape data of the artificial nail to be formed is generated from the shape information of the artificial nail. Also, in the design process 82, modeling data to be used in the modeling process 84 is generated from the generated shape data.
Furthermore, the design process 82 sets modeling conditions in the modeling process 84. The modeling conditions include settings (or designation) of a 3D printer as a three-dimensional modeling device used in the modeling process 84 to manufacture a model, and settings of the wavelength of light (e.g., central wavelength or wavelength band), light intensity, irradiation time, etc. when operating the 3D printer. The modeling conditions also include a photocurable composition used in photomodeling.

If the shape information of the artificial nail to be formed includes a specification of a 3D printer and a specification of modeling conditions, in the design process 82, the 3D printer and modeling conditions are specified based on the shape information of the artificial nail to be formed. Also, if the shape information of the artificial nail to be formed does not include a specification of a 3D printer and a specification of modeling conditions, in the design process 82, the 3D printer and modeling conditions are specified by input, or are selected from a preset combination and specified.

Furthermore, the design process 82 specifies the curing conditions in the curing process 88. The curing conditions include the specification of a light curing device to be used to light-cure the model in the curing process 88, and the wavelength (i.e., central wavelength or wavelength band) of the light (e.g., laser light) when operating the light curing device, the light intensity, the light irradiation time, etc. The curing conditions are set based on the shape information of the artificial nail to be formed if the shape information of the artificial nail to be formed includes the specification of a light curing device and the specification of the curing conditions. Furthermore, if the shape information of the artificial nail to be formed does not include the specification of a light curing device and the specification of the curing conditions, the design process 82 specifies the curing conditions in the same manner as the modeling conditions.

In the design process 82, when generating modeling data from shape data, the dimensions and shape of the artificial nail as a modeled object after hardening are predicted based on the modeling conditions, curing conditions, and pre-set prediction information, and modeling data is generated so that the predicted dimensions and shape of the artificial nail match the dimensions and shape of the artificial nail to be formed (however, this also includes a state in which they can be considered to be approximately the same).
As a result, in the modeling step 84, a modeled object is manufactured by photo-modeling based on the modeling data and modeling conditions generated in the design step 82, and in the curing step 88, the modeled object is photo-cured based on the curing conditions specified in the design step 82. By manufacturing an artificial nail by further photo-curing the photo-modeled object, it is possible to obtain an artificial nail having excellent bending strength and bending elasticity.

Meanwhile, in the manufacturing process of the artificial nail in this embodiment, an evaluation step 90 is provided. In the evaluation step 90, it is evaluated whether an artificial nail of the same size (dimensions) and shape as the artificial nail to be formed has been manufactured. In this case, in the evaluation step 90, post-curing data as three-dimensional data of the shaped object after curing (e.g., after photo-curing in the curing step 88) is obtained, and shape data and shaping data of the artificial nail to be formed are obtained from the design step 82. In the evaluation step 90, the post-curing data is collated (or compared) with the shape data to evaluate the manufactured artificial nail.
If the dimensions and shape of the manufactured artificial nail are evaluated to be similar to the dimensions and shape of the artificial nail to be formed in the evaluation step 90, the manufactured artificial nail is delivered to the customer as a product.

Figure 2 also shows an outline of an artificial nail in a perspective view, with the artificial nail 10 represented by the shape data shown in a two-dot chain line, and the artificial nail (i.e., the hardened molded object) 12 represented by the post-molding data shown in a solid line. Note that in Figure 2, the X, Y, and Z axes are shown with the base side (i.e., the side opposite the fingertip) of the artificial nails 10 and 12 being the origin side of the Z axis.

Generally, when a model is cured, the length, width, thickness, and volume of the cured model shrink more or less than the uncured model. Models produced by photo-modeling using a photocurable composition also shrink during photo-modeling and after photo-curing compared to the uncured model. That is, the model shrinks when photo-modeling is performed in the modeling process 84 based on the modeling data, and shrinks more or less when photo-curing in the curing process 88.
The shrinkage of a modeled object during photo-modeling and photo-curing is affected by the photocurable composition used in photo-modeling, modeling conditions, curing conditions, etc. In addition, the shrinkage of a modeled object during photo-modeling and photo-curing is also considered to be affected by the environmental conditions (e.g., temperature and humidity) when the modeled object is photo-cured and cured.
The artificial nail is formed to be thin and has a warp in at least one of the length and width directions so that the surface that comes into contact with the surface of the bare nail (hereinafter also referred to as the back surface of the artificial nail) is concave. Therefore, slight shrinkage of the artificial nail 12 after hardening changes the warp, and the fit of the artificial nail 10 when actually worn on the nail changes.

In this embodiment, the predicted information is based on at least the photocurable composition (or components of the photocurable composition) used in the modeling, the modeling conditions, and the curing conditions, and the shrinkage state of the modeled object after curing is predicted. The predicted information may also include environmental information such as temperature and humidity in each of the modeling environment and the curing environment. The predicted shrinkage state includes dimensions such as length, width, thickness, and volume, as well as changes in warping due to the thickness of the artificial nail, etc.

In the design process 82 according to this embodiment, when generating modeling data to be used in photo-fabrication from the shape data of the artificial nail, the shrinkage state (e.g., shrinkage amount or shrinkage rate, change in warping, etc.) that will occur in the model after hardening is predicted, and the shape data is corrected based on the predicted shrinkage state to generate modeling data for the artificial nail. The modeling data is generated so that the artificial nail 12 after hardening will have the same length, width, thickness, and volume as the artificial nail 10 to be formed, and so that the warping that occurs in the artificial nail 12 will be similar to the warping of the artificial nail 10.

Furthermore, in the design process 82, the prediction information is updated using the post-curing data of the artificial nail 10 acquired in the evaluation process 90 and the shaping conditions and curing conditions for manufacturing the artificial nail 10. Furthermore, it is more preferable that the update of the prediction information includes environmental information.
In addition, if it is evaluated in the evaluation process 90 that there is a difference in dimensions, shape, etc. between the artificial nail represented by the shape data and the artificial nail represented by the post-cured data after curing (for example, if the manufactured artificial nail 12 cannot be considered to be the artificial nail 10), the prediction information is updated, and the shape data of the corresponding artificial nail is re-corrected based on the updated prediction information to regenerate the modeling data, and the artificial nail 12 is remodeled (i.e., remanufactured) based on the regenerated modeling data.

Figure 3 shows a block diagram of the schematic configuration of the molding design system 20 according to this embodiment. The molding design system 20 according to this embodiment uses a CAD (Computer Aided Design) system, which performs the processing function in the design process 82. The molding design system 20 preferably includes a configuration that performs at least the processing function in the evaluation process 90, and may also include a configuration that performs the processing function in the shape acquisition process 80. Furthermore, the molding design system 20 may include a configuration that performs the processing functions of each of the molding process 84 and the hardening process 88. The molding design system 20 according to this embodiment includes, as an example, a configuration that performs the processing mechanisms in the shape acquisition process 80, the molding process 84, the hardening process 88, and the evaluation process 90, so that the molding design system 20 also functions as a manufacturing system for the artificial nail 10.

The modeling design system 20 is configured by a computer including a calculation processing unit 22 equipped with a CPU, a main memory unit 24, an input unit 26, an output unit 28, an auxiliary memory unit 30, and an interface unit 32, and the calculation processing unit 22, the main memory unit 24, the input unit 26, the output unit 28, the auxiliary memory unit 30, and the interface unit 32 are interconnected via a bus 34.

The main memory unit 24 stores the operation program (OS) of the calculation processing unit 22, and the modeling design system 20 operates when the calculation processing unit 22 reads and executes the operation program from the main memory unit 24. The input unit 26 is provided with input devices such as a keyboard, mouse, and tablet, and the output unit 28 is provided with output devices such as a display and printer.

The interface unit 32 of the modeling design system 20 is connected to a three-dimensional measuring device (i.e., a 3D scanner) 36 used as a reading unit when the modeling design system 20 functions as a shape acquisition process 80 and an evaluation process 90, a three-dimensional modeling device (i.e., a 3D printer) 38 used in the modeling process 84, and a light curing device 40 used as a curing device in the curing process 88.
As the 3D printer 38, for example, a desktop 3D printer Form2 (manufactured by Formlabs) or the like is used.

In addition, in this embodiment, an environmental sensor 42 is provided to detect environmental information such as temperature and humidity during modeling in the modeling process 84 (e.g., the installation environment of the 3D printer 38), and an environmental sensor 44 is provided to detect environmental information such as temperature and humidity during curing in the curing process 88 (e.g., the installation environment of the light curing device 40). Each of the environmental sensors 42 and 44 is connected to the modeling design system 20.

The modeling design system 20 may preferably have the interface unit 32 connected to a dedicated communication line network such as a LAN (Local Area Network) or a public communication line network such as the Internet. In this case, the 3D scanner 36, the 3D printer 38, the light curing device 40, and the environmental sensors 42, 44 can be connected to the modeling design system 20 by being able to transmit and receive data (or information) to and from each other via a dedicated communication line network or a public communication line network. As a result, even if the 3D scanner 36, the 3D printer 38, the light curing device 40, and the modeling design system 20 are installed in different locations (e.g., remote locations), the modeling design system 20 can control the 3D scanner 36, the 3D printer 38, and the light curing device 40, and the modeling design system 20 can be connected to one or more 3D scanners 36, 3D printers 38, and light curing devices 40, thereby forming an artificial nail manufacturing system.

The auxiliary memory unit 30 of the modeling design system 20 is, for example, a non-volatile storage medium such as a hard disk device on which information can be rewritten. A modeling design program 50, for example, commercially available CAD software (e.g., 3D CAD software), is installed in the auxiliary memory unit 30. The auxiliary memory unit 30 also stores a shape acquisition program 52, a modeling program 54, a light curing program 56, an evaluation program 58, and the like. Furthermore, the auxiliary memory unit 30 has a database 60 of prediction information formed therein, and also stores a prediction program 62 and a learning program 64.

The arithmetic processing unit 22 reads out and executes the modeling design program 50 and the shape acquisition program 52 from the auxiliary memory unit 30, and the modeling design system 20 functions as a design unit that handles the design process 82 and a reception unit that handles the shape acquisition process 80. By functioning as a reception unit and a design unit, the modeling design system 20 receives shape information of the artificial nail and generates shape data from the received shape information. In addition, the modeling design system 20 generates modeling data from the shape data and sets modeling conditions and curing conditions.

In the modeling design system 20, the interface unit 32 functions as an output unit, so that the modeling data, modeling information, and curing information can be output.
In addition, when the calculation processing unit 22 executes the modeling program 54, the modeling design system 20 functions as an output unit and also as a modeling unit that is responsible for the modeling process 84, and controls the operation of the 3D printer 38 to photo-model the artificial nail.
Furthermore, the calculation processing unit 22 reads out and executes the light curing program 56 and the evaluation program 58, so that the modeling design system 20 functions as a curing unit that performs the curing process 88 and an evaluation unit that performs the evaluation process 90. As a result, the modeling design system 20 controls the operation of the light curing device 40 to perform light curing of the artificial nail to form the artificial nail 12. In addition, the modeling design system 20 controls the operation of the 3D scanner 36 to obtain post-curing data from the artificial nail 12 and evaluate the obtained post-curing data.

When the calculation processing unit 22 reads and executes the learning program 64, the modeling design system 20 functions as a learning unit and builds (or updates) the database 60. Also, when the calculation processing unit 22 reads and executes the prediction program 62, the modeling design system 20 functions as a prediction unit that predicts post-hardening data for shape data or modeling data from the prediction information stored in the database 60. Also, when the modeling design system 20 functions as a prediction unit, the modeling design system 20 generates modeling data in which the shape data has been corrected based on the prediction results.

The database 60 stores, as prediction information, shape information of the artificial nail in association with shaping information and hardening information. The shape information of the artificial nail stored in the database 60 includes shape data indicating at least the dimensions and shape of the artificial nail to be formed.
The modeling information associated with the shape information of the artificial nail includes at least the modeling data applied to the photo-lithography, information specifying the 3D printer used for the photo-lithography based on the modeling data, and information specifying the photocurable composition used for the photo-lithography. In other words, the modeling information can include designation of modeling conditions.

The curing information associated with the shape information of the artificial nail includes at least information identifying the light curing device 40 used for light curing, the wavelength of the light used for light curing, the light irradiation time, and the curing environment (e.g., temperature and humidity). That is, the curing information can include specification of the curing conditions. The curing information is also associated not only with the shape information of the artificial nail, but also with the shaping information associated with the shape information of the artificial nail.

Furthermore, the database 60 includes evaluation information of the manufactured artificial nail 12, and the evaluation information is associated with the shape information, shaping information, and curing information of the artificial nail. The evaluation information includes at least the post-curing data, and also includes information indicating the contraction state as a difference between the shaping data of the shaping information associated with the shape data and the post-curing data. The information indicating the contraction state includes the amount of contraction (or may be the contraction rate) and shape change (for example, change in warpage) occurring in the artificial nail 12.
Furthermore, the shape information of the artificial nail may include information about the customer who requested the manufacture of the artificial nail 10, and by making it possible to identify the person who will wear the artificial nail to be formed based on the customer information, the artificial nail can be manufactured based on the customer information stored in the database 60.

The molding information may include the environmental conditions (e.g., temperature and humidity) when the artificial nail is molded. In addition, since the hardening speed, etc. may change depending on the environmental conditions (e.g., temperature and humidity) when the molded artificial nail is hardened, it is preferable that the hardening information includes the environmental conditions (e.g., temperature and humidity) when the molded artificial nail is hardened.

The modeling design system 20 functions as a learning unit, acquiring each of the shape information, modeling information, hardening information, and evaluation information of the artificial nail, storing each of the shape information, modeling information, hardening information, and evaluation information of the artificial nail in association with each other in the database 60, and constructing and updating the database 60.

As a result, when the modeling design system 20 functions as a prediction unit, the modeling information and hardening information are set, the shrinkage state is predicted, and modeling data is generated so that the hardened data is similar to the shape data. Note that the initial value of the prediction information stored in advance in the database 60 may be an arbitrarily set initial value (e.g., a default value), or the evaluation result when modeling average shape information (e.g., model data, average data, or reference data) about fingernails using the reference modeling information and hardening information may be used.

Next, with reference to FIG. 4, a description will be given of the manufacture of an artificial nail by the modeling design system 20 (i.e., modeling system) according to this embodiment.
In the manufacture of the artificial nail according to the present embodiment, a photocurable composition is used as a photo-molding material. The photocurable composition applied to the present embodiment is not particularly limited as long as it can be used for photo-molding, but a photocurable composition containing at least one (meth)acrylic monomer selected from the di(meth)acrylic monomers having no hydroxyl group or carboxy group in one molecule and two aromatic rings and two (meth)acryloyloxy groups (hereinafter referred to as (meth)acrylic monomer (X)) with a weight average molecular weight of 400 to 800, at least one (meth)acrylic monomer selected from the (meth)acrylic monomers having at least one ring structure and one (meth)acryloyloxy group in one molecule and a weight average molecular weight of 130 to 350 (hereinafter referred to as di(meth)acrylic monomer (D)), and a photopolymerization initiator is preferable.

It is preferable that the wavelength of the light (e.g., laser light) used for photo-modeling in the 3D printer 38 and the wavelength of the light (e.g., laser light) used for photo-curing in the photo-curing device 40 are matched to the wavelength of the photopolymerization initiator.

As shown in FIG. 4, in the manufacture of the artificial nail 10 (or the artificial nail 12 to be used as the artificial nail 10), in the first step 100, shape information of the artificial nail 10 to be formed is acquired. To acquire the shape information, for example, if there is a sample of the artificial nail 10 to be formed (which may be, for example, a person's hand with an actual nail), the sample is attached to a 3D scanner 36 and the surface shape of the nail is read three-dimensionally (i.e., stereoscopically). This provides a three-dimensional image of the sample, and shape data 0 of the artificial nail 10 can be constructed from the three-dimensional image of the sample. Such a three-dimensional image may be input to the modeling design system 20 via a dedicated communication line network or a public communication line network.

The shape information of the artificial nail 10 preferably includes customer information and information regarding the finger to which the artificial nail 10 is to be applied. In addition, when manufacturing a set of 10 artificial nails 10, assuming that they will be worn on each finger of both hands of one person, information specifying the finger on which each of the 10 artificial nails 10 is to be worn is also acquired for each of the 10 artificial nails 10. In the modeling design system 20, as an example, a description will be given of manufacturing a set of 10 artificial nails 10 (i.e., artificial nails to be worn on the nails of each of a person's fingers on both the left and right hands).

If the photocurable composition used to manufacture the artificial nail 10 is specified, the specified photocurable composition (for example, the components contained in the photocurable composition, the ratio of the components contained, or the product name of the photocurable composition) is accepted in step 100. In addition, if the shaping conditions or curing conditions for manufacturing the artificial nail 10 are specified, these specifications are accepted in step 100.

In the next step 102, shape data is generated based on the acquired shape information of the artificial nail 10. Commercially available 3D CAD software or the like is used to generate the shape data, and the shape data can be created from the shape information (e.g., a three-dimensional image of a sample, etc.).

Once the shape data is created, in step 104, the shrinkage state that will occur in the artificial nail 12 when the artificial nail 12 is manufactured by photo-modeling and then photo-curing is predicted. At this time, if the photocurable composition, modeling conditions, and curing conditions are specified in the shape information, the shrinkage state is read (or predicted) from the prediction information (e.g., database 60) based on the photocurable composition, modeling conditions, and curing conditions specified in the shape information. Also, if at least one of the photocurable composition, modeling conditions, and curing condition resin is not specified in the shape information, the unspecified conditions are set to match the 3D printer 38 and photocuring device 40 connected to the modeling design system 20.

In addition, when predicting the shrinkage state, it is more preferable to detect environmental information (e.g., temperature and humidity) of the installation environment of the 3D printer 38 used for photopolymerization and environmental information (e.g., temperature and humidity) of the installation environment of the photocuring device 40 used for photocuring by the environmental sensors 42, 44, and predict the shrinkage state including the detected environmental information.
Thereafter, in step 106, the shape data is corrected based on the predicted contraction state, thereby generating modeling data.

Here, an example of generation of modeling data according to this embodiment will be described with reference to FIG. 5. Note that FIG. 5 shows an oblique view of an image of a model to be optically modeled, which is represented by the modeling data.

In this embodiment, when manufacturing one set of artificial nails 10, modeling data is generated so that two units 70L and 70R are photo-modeled, one for each hand, with five units each. In units 70L and 70R, artificial nails 72A, 72B, 72C, 72D, and 72E are arranged from artificial nail 72A on the thumb side to artificial nail 72E on the little finger side.

In this embodiment, a 3D printer 38 to which the SLA method is applied is used, and a roughly rectangular flat base 74 is provided on the platform side of the 3D printer 38, and five stands 76 are provided on the base 74, and the artificial nails 72A to 72E are set to be formed on the stands 76. The artificial nails 72A to 72E are also arranged so that the side opposite the fingertip side is in contact with the stands 76.

On the other hand, the base 74 is provided with an ID 78 as an identification code for identifying the artificial nails 72A-72E. Any code capable of identifying the artificial nails 72A-72E in each of the units 70L and 70R can be used as this ID 78. Furthermore, the ID 78 is set so that it is different between the units 70L and 70R, and so that it is clearly identifiable that the units 70L and 70R are a set (i.e., one set).

In this embodiment, an alphabetical arrangement corresponding to the customer's name is used as an example of ID78. Furthermore, ID78L, which includes a code indicating that it corresponds to the nails on the left hand, is used as ID78 for unit 70L, and ID78R, which includes a code indicating that it corresponds to the nails on the right hand, is used as ID78 for unit 70R.

Specifically, the code for identifying the thumb (i.e., thumb nail) is "0" and the code for identifying the little finger (i.e., little finger nail) is "4". In the unit 70L, an ID 78L including a code L0 indicating the artificial nail 72A of the thumb of the left hand, a code L4 indicating the artificial nail 72E of the little finger, and an arrow indicating the arrangement direction from the artificial nail 72A of the thumb to the artificial nail 72E of the little finger are formed. In addition, in the unit 70R, an ID 78R including a code R0 indicating the artificial nail 72A of the thumb of the left hand, a code R4 indicating the artificial nail 72E of the little finger, and an arrow indicating the arrangement direction from the artificial nail 72A of the thumb to the artificial nail 72E of the little finger are formed.
The three-dimensional data file (e.g., STL file) of the modeling data thus formed contains shape data of each artificial nail as modeling data corrected based on the prediction information. In the STL file, data is generated so that the artificial nail is photo-modeled from the base 74 side in the 3D printer 38.

In addition, when multiple sets of artificial nails 10 are photo-fabricated in parallel, an STL file is generated as composite data in which data is arranged so that the units 70L and 70R of each set are photo-fabricated side by side on a single platform.
When the STL file is generated in this manner, the process proceeds to step 108, where a photo-fabrication process is performed. In the photo-fabrication process, a photocurable composition set in the modeling conditions is used in the 3D printer 38. This results in a photo-fabricated object in which the photocurable composition is laminated in layers (e.g., layers with a thickness of 100 μm). This photo-fabricated object is formed by forming each set of artificial nails on each stand 76 of the base 74, and performing photo-fabrication on one or more sets. The modeling design system 20 detects the environmental conditions (e.g., environmental temperature and environmental humidity) of the installation environment of the 3D printer 38 during modeling using the environmental sensor 42, and stores the detected environmental conditions in the database 60 to include them in the prediction information.

The time required for photo-fabrication in 3D printer 38 is the time it takes for the platform to move up and down and the time it takes for light (e.g., laser light) to be emitted at each moving position. If the platform of 3D printer 38 is large enough to photo-fabricate, for example, 16 sets, even if the time required for photo-fabrication of two sets of artificial nails is 60 minutes, the time required for photo-fabrication of 16 sets of artificial nails, which is eight times as many as two sets, will be about 120 minutes, which is twice as long. Also, each set is assigned an ID 78 to units 70L and 70R. Therefore, even if multiple sets are photo-fabricated in parallel, each of the photo-fabricated artificial nails can be identified without mistake.

The manufacturing process for artificial nails applied by the modeling design system 20 includes a cleaning process 86. Immediately after photofabrication, uncured liquid (i.e., liquid photocurable composition) adheres to the surfaces of the units 70L and 70R. Therefore, when the platform is removed from the 3D printer 38, the uncured liquid adhering to the photofabricated object on the platform is scraped off.

In the cleaning process 86, the uncured liquid that has not been scraped off and remains on each of the stereolithography objects (i.e., units 70L and 70R) is removed. The cleaning process 86 is performed on the artificial nail that has been removed from the platform (i.e., the artificial nail unit that is attached to the base 74 via the stand 76). In the cleaning process 86, for example, an ultrasonic cleaner using ethanol (EtOH), isopropyl alcohol (IPA), or the like, is used as the cleaning liquid.

As shown in Fig. 4, in step 110, the artificial nail units 70L, 70R after the cleaning process are subjected to a photo-curing process using the photo-curing device 40. The photo-curing process is performed with light of a wavelength (e.g., laser light), light intensity, and light irradiation time designated by the curing conditions. In this way, the artificial nail 12 is manufactured by photo-molding the artificial nail 10.
The modeling design system 20 stores the installation environment of the light curing device 40 acquired by the environmental sensor 44 in the database 60 as predicted information associated with the shape information of the artificial nail 10 .

Thereafter, in step 112, each of the units 70L, 70R of the hardened artificial nail 12 is attached to the 3D scanner 36 and read, thereby obtaining hardened data, which is three-dimensional data of each of the artificial nails 12 formed in the units 70L, 70R.
In steps 114 and 116, the artificial nail 12 is evaluated against the artificial nail 10 by comparing the post-curing data and the shape data for each artificial nail 12. At this time, the dimensions (e.g., length, width, thickness, volume, etc.) and outer shape (e.g., warping in each of the length and width directions) of the artificial nail 12 indicated by the post-curing data are compared with those of the artificial nail 10, and if each artificial nail 12 matches or can be considered to match the artificial nail 10 in terms of dimensions and shape (i.e., if it is within an error range set as acceptable), it is evaluated as good and a positive determination is made in step 116.

If the determination in step 116 is affirmative, the process proceeds to step 118, where the post-curing data of the artificial nail 12 is stored in the database 60 in association with the shape information of the artificial nail 10. At this time, the post-curing data is stored in the database 60 together with shrinkage information, including the shrinkage state of the post-curing data relative to the modeling data of the artificial nail 10.

On the other hand, if at least one of the dimensions and shape of the artificial nail 12 indicated by the post-curing data differs from that of the artificial nail 10 indicated by the shape data (for example, if one of the dimensions and shape of the artificial nail 12 with respect to the artificial nail 10 exceeds a preset error range), the artificial nail 12 is evaluated as defective and a negative judgment is made in step 116.
If a negative judgment is made in step 116, the process proceeds to step 120. In step 120, the difference between the post-curing data and the shaping data (e.g., the amount of shrinkage or shrinkage rate, the degree of warping) is calculated, and is stored in the database 60 in association with each of the shape data (or shape information), the shaping data (or shaping information), and the curing information. At the same time, in step 120, the prediction information for the artificial nail 10 is updated.

Then, the process proceeds to step 104, where the shape data of the artificial nail 10 is corrected (or re-corrected) based on the updated prediction information to generate modeling data, and the artificial nail 10 is remade. This may be done on a set basis, but in this embodiment, each of the units 70L and 70R is provided with an ID 78 that can identify the other units, so that the artificial nail can be remanufactured on a unit basis. As a result, if the manufactured artificial nail 12 is evaluated as being good, the manufactured artificial nail 12 is delivered (or manufactured) as the artificial nail 10.

In this way, when generating modeling data from the shape data of the artificial nail 10, the modeling design system 20 predicts the state of shrinkage after hardening and generates modeling data based on the prediction result. This makes it possible to manufacture the artificial nail 12 that will become the artificial nail 10 with high accuracy. This results in an artificial nail 10 that fits well.

The prediction information used for prediction includes the photocurable composition based on photo-modeling, modeling information according to the modeling conditions, and curing information according to the curing conditions, so that it is possible to predict with high accuracy not only the shrinkage state for each photo-modeling, but also the shrinkage state after photo-curing. It is preferable that the prediction information includes environmental information during photo-modeling and environmental information during photo-curing, so that, for example, changes in the shrinkage state caused by slight changes in the curing speed (for example, differences in environmental information) can be predicted with high accuracy.

Furthermore, it is preferable that the prediction information includes customer information that identifies the artificial nail 10, so that when a similar artificial nail is requested (or requested) to be manufactured, the requested artificial nail 10 can be manufactured easily and with high accuracy.

Furthermore, the modeling design system 20 acquires post-curing data and updates (or learns) the prediction information by associating the shrinkage information including the acquired post-curing data with the shape information. Therefore, as the number of artificial nails 10 to be formed increases, the shrinkage state after photo-curing can be predicted with higher accuracy, making it possible to manufacture artificial nails 10 with higher accuracy.
Furthermore, the modeling design system 20 manufactures a set of artificial nails 10 for one person and each set of artificial nails 10 and each artificial nail 10 in the set can be identified, so that it is easy to manufacture a large number of artificial nails 12 and it is also possible to clearly indicate which artificial nail 10 each artificial nail 12 corresponds to.

In this embodiment, the modeling design system 20 has processing functions for the shape acquisition process 80, the modeling process 84, the hardening process 88, and the evaluation process 90, but this is not limited to the above. A computer for control may be provided separately from the modeling design system 20 for the shape acquisition process 80, the modeling process 84, the hardening process 88, and the evaluation process 90. In this case, it is preferable that the computers provided for each of the shape acquisition process 80, the modeling process 84, the hardening process 88, and the evaluation process 90 are connected to the modeling design system 20 via a dedicated communication line network or a public communication line network, etc., so that data can be transmitted and received. This makes it easy to carry out the process from accepting the artificial nail 10 to be formed to manufacturing the artificial nail 12 that will be used as the artificial nail 10. Moreover, the artificial nail 12 that will be used as the artificial nail 10 can be manufactured efficiently and with high precision.

The present invention will be described in detail below with reference to examples, but the present invention is not limited to these examples.

[Examples 1 to 30, Comparative Examples 1 to 7]
<Preparation of Photocurable Composition>
The components shown in Tables 1 to 4 below were mixed to obtain photocurable compositions.
<Measurement and Evaluation>
The photocurable compositions thus obtained were subjected to the following measurements and evaluations. The results are shown in Tables 1 to 4.

(Viscosity of Photocurable Composition)
The viscosity of the photocurable composition was measured using an E-type viscometer at 25° C. and 50 rpm.

(Bending strength and bending modulus of elasticity of stereolithography)
The photocurable composition thus obtained was shaped into a shape having a size of 80 mm × 10 mm × thickness of 4 mm using a 3D printer (Form Lab, Form2) to obtain a shaped object. The shaped object thus obtained was irradiated with ultraviolet light having a wavelength of 365 nm at 5 J/ ^cm2 for main curing to obtain a photo-molded object.
The bending strength and bending modulus of the test pieces were measured in accordance with ISO 178 (or JIS K 7171). These measurements were performed using a tensile testing device (manufactured by Intesco Corporation) under conditions of a punch radius of 5 mm, a support radius of 5 mm, a support distance of 64 mm, and a pressing speed of 2 mm/min.

When the photocurable composition is used for producing an artificial nail or the like, the bending strength is preferably 10 MPa or more, and more preferably 40 MPa or more.
In this case, the flexural modulus is preferably 400 MPa or more, and more preferably 1500 MPa or more.

(Bending resistance of photolithography (0.5 mm thickness))
The obtained photocurable resin composition was shaped using a 3D printer (FormLab, Form2) to have an outer diameter of 8 mm, an inner diameter of 7.5 mm (however, the thickness was 0.5 mm), a circumference of 90°, and a length of 15 mm. The composition was then fully cured by irradiating it with ultraviolet light having a wavelength of 365 nm at 5 J/ ^cm2 to obtain a photo-molded object.

One of the resulting shaped objects (hereinafter referred to as "artificial nail 1") was placed under a metal cube measuring 50 mm in length, 50 mm in width, and 50 mm in height, and a load of 20 kg was applied from above, after which it was visually inspected to see if it had cracked. A total of five artificial nails 1 were evaluated, and five that had not cracked and maintained their shape were rated "A," two to four that had not cracked and maintained their shape were rated "B," and zero to one that had not cracked and maintained their shape were rated "C."

(Bending resistance of photolithography (1.0 mm thickness))
The obtained photocurable resin composition was shaped using a 3D printer (FormLab, Form2) to have an outer diameter of 8 mm, an inner diameter of 7 mm (however, the thickness was 1.0 mm), a circumference of 90°, and a length of 15 mm. The composition was then fully cured by irradiating it with ultraviolet light having a wavelength of 365 nm at 5 J/ ^cm2 to obtain a photomolded object.

One of the resulting shaped objects (hereinafter referred to as "artificial nail 2") was placed under a metal cube measuring 50 mm in length, 50 mm in width, and 50 mm in height, and a load of 20 kg was applied from above, after which it was visually inspected to see if it had cracked. A total of five artificial nails 2 were evaluated, and five that had not cracked and maintained their shape were rated "A," two to four that had not cracked and maintained their shape were rated "B," and zero to one that had not cracked and maintained their shape were rated "C."

(Tensile strength and elongation of stereolithography)
The obtained photocurable resin composition was shaped into a size of 30 mm x 10 mm x 0.5 mm thick using a 3D printer (FormLab, Form2), and then irradiated with ultraviolet light having a wavelength of 365 nm at 5 J/ ^cm2 for full curing to obtain a photo-molded object.

In accordance with the method described in ISO 527-1 (or JIS K7161), the obtained molded object (hereinafter referred to as the "tensile test piece") was measured using a tensile testing device (manufactured by Intesco Co., Ltd.) under conditions of a chuck distance of 20 mm and a tensile speed of 5 mm/min, and the tensile strength (unit: MPa) and elongation (unit: %) at the time when the tensile test piece broke were obtained.

(Tg (glass transition temperature) of stereolithography object)
The tensile test specimens were measured with a differential scanning calorimeter (DMS) (DMS6100 dynamic viscoelasticity measuring device manufactured by Hitachi High-Tech Science Corporation) at a heating rate of 5° C./min to obtain Tg (i.e., glass transition temperature).

In Tables 1 to 4, the numbers in the "Photocurable composition composition" column for each example and comparative example are expressed in parts by mass.

In Tables 1 to 4, the structures of the (meth)acrylic monomers (X) are as follows:
Here, ABE-300, A-BPE-4, and A-BPE-10 are acrylic monomers manufactured by Shin-Nakamura Chemical Co., Ltd., BP-4PA is an acrylic monomer manufactured by Kyoeisha Chemical Co., Ltd., and BP-2EM is a methacrylic monomer manufactured by Kyoeisha Chemical Co., Ltd.

In Tables 1 to 4, the structures of the (meth)acrylic monomers (D) are as follows:
Here, PO-A, POB-A, M-600A and 4EG-A are acrylic monomers manufactured by Kyoeisha Chemical Co., Ltd., PO is a methacrylic monomer manufactured by Kyoeisha Chemical Co., Ltd., A-LEN-10 and APG-200 are manufactured by Shin-Nakamura Chemical Co., Ltd., THFA and AIB are manufactured by Osaka Organic Chemical Industry Co., Ltd., FA511AS is manufactured by Hitachi Chemical Co., Ltd., and CHDMMA is an acrylic monomer manufactured by Nippon Kasei Co., Ltd.

In Tables 1 to 4, the structures of the photopolymerization initiators are as follows:
Here, Irg819 is "Irgacure 819" (an acylphosphine oxide compound) manufactured by BASF, Irg184 is "Irgacure 184" (an alkylphenone compound) manufactured by BASF, and TPO is "Irgacure TPO" (an acylphosphine oxide compound) manufactured by BASF.

As shown in Tables 1 to 4, in Examples 1 to 30 containing the (meth)acrylic monomer (X) and the (meth)acrylic monomer (D), stereolithography was able to obtain objects having particularly excellent bending resistance. In addition, the bending strength, bending modulus, bending resistance, tensile strength, and elongation were well-balanced.
The viscosities and glass transition temperatures (ie, Tg) of the photocurable compositions of Examples 1 to 30 were in ranges suitable for stereolithography.
From the above, it was confirmed that the photocurable compositions of Examples 1 to 30 are particularly suitable for producing artificial nails by stereolithography.

The disclosures of Japanese Patent Applications Nos. 2017-066067 and 2017-084814 are incorporated herein by reference in their entirety. All documents, patent applications, and technical standards described herein are incorporated herein by reference to the same extent as if each individual document, patent application, and technical standard was specifically and individually indicated to be incorporated by reference. The foregoing description of exemplary embodiments of the present invention has been provided for purposes of illustration and description, and is not intended to be exhaustive or to limit the invention to the precise forms disclosed. Obviously, many modifications and variations will be apparent to those skilled in the art. The above embodiments have been selected and described in order to best explain the principles and practical application of the invention and to enable others skilled in the art to understand the invention with various embodiments and various modifications as suited to the particular use envisaged. It is intended that the scope of the present invention be defined by the following claims and their equivalents.

Claims (16)

a receiving step of receiving shape information capable of identifying a three-dimensional external shape of the artificial nail to be formed;
a prediction step of predicting, based on predetermined prediction information, a shrinkage state including a change in warpage that occurs in a model that has been photo-modeled by a three-dimensional modeling device based on the three-dimensional modeling data and predetermined modeling information and then photo-cured by a curing device under predetermined curing conditions;
a generating step of correcting three-dimensional shape data of the artificial nail to be formed, obtained from the shape information, based on the prediction result of the predicting step, to generate three-dimensional modeling data for optically modeling a model of the artificial nail to be formed by the three-dimensional modeling device;
an output step of outputting the modeling data generated by the generating step;
Including,
the prediction information is a database in which shape data of the artificial nail, three-dimensional cured data indicating an outer shape of a modeled object obtained by photolithography and photo-curing after curing, modeling information indicating modeling conditions including the three-dimensional modeling device and a photolithography material used for photolithography in the three-dimensional modeling device, and applied modeling data , and curing information indicating the curing conditions are stored in association with each other;
How to generate modeling data. an acquiring step of acquiring three-dimensional post-curing data indicating an outer shape of a modeled object after curing, the modeled object being photo-cured based on the modeling data;
an updating step of updating the prediction information based on the after-curing data acquired in the acquiring step, shape data of the artificial nail to be formed corresponding to the after-curing data, a prediction result predicted in the predicting step for the shape data, and the modeling data generated based on the prediction result;
The method for generating modeling data according to claim 1 , further comprising: The method for generating modeling data according to claim 1 or 2, further comprising a synthesis step of synthesizing the modeling data of the plurality of artificial nails to be formed so that the plurality of artificial nails to be formed are arranged on a substrate and integrally formed by the three-dimensional modeling device. The method for generating modeling data according to claim 3, wherein the synthesis step includes providing data to be formed on the substrate with identification information that identifiably specifies each of the multiple artificial nails to be formed. The method for generating modeling data according to claim 3 or 4, wherein the synthesis step synthesizes the modeling data so that a plurality of the substrates, each of which has a plurality of the artificial nails to be formed arranged thereon, are photo-modeled in parallel by the three-dimensional modeling device. a receiving step of receiving shape information capable of identifying a three-dimensional external shape of the artificial nail to be formed;
a prediction step of predicting, based on predetermined prediction information, a shrinkage state including a change in warpage that occurs in a model that has been photo-modeled by a three-dimensional modeling device based on the three-dimensional modeling data and predetermined modeling information and then photo-cured by a curing device under predetermined curing conditions;
a generating step of correcting three-dimensional shape data of the artificial nail to be formed, obtained from the shape information, based on the prediction result of the predicting step, to generate three-dimensional modeling data for optically modeling a model of the artificial nail to be formed by the three-dimensional modeling device;
a modeling step of generating a modeled object by the three-dimensional modeling device based on the modeling data generated by the generating step;
a curing step of further photo-curing the object modeled in the modeling step;
Including,
the prediction information is a database in which shape data of the artificial nail, three-dimensional cured data indicating an outer shape of a modeled object obtained by photolithography and photo-curing after curing, modeling information indicating modeling conditions including the three-dimensional modeling device and a photolithography material used for photolithography in the three-dimensional modeling device, and applied modeling data , and curing information indicating the curing conditions are stored in association with each other;
A method for producing artificial nails. an acquiring step of acquiring three-dimensional post-curing data indicating an outer shape of the object from the object photo-cured in the curing step;
an evaluation step of evaluating the hardened object by comparing the hardened data with shape data of the artificial nail to be formed;
7. The method of claim 6, further comprising: The method for manufacturing an artificial nail according to claim 7, further comprising an update step for updating the prediction information based on the evaluation results of the evaluation step. The method for manufacturing an artificial nail according to any one of claims 6 to 8, further comprising a cleaning step, prior to the curing step, of removing excess photo-molding material used in the photo-molding of the object from the object photo-molded in the molding step. a three-dimensional modeling device that optically models a three-dimensional object based on input three-dimensional modeling data;
a curing device that photo-cures the object photo-modeled by the three-dimensional modeling device;
a modeling design device including: a receiving unit that receives shape information capable of identifying a three-dimensional external shape of the artificial nail to be formed; a prediction unit that predicts, based on predetermined and stored prediction information, a shrinkage state including a change in warp that occurs in a model that is photo-modeled by the three-dimensional modeling device based on the three-dimensional modeling data and predetermined modeling information and then photo-cured by the curing device under predetermined curing conditions; a generation unit that corrects the three-dimensional shape data of the artificial nail to be formed obtained from the shape information based on the prediction result of the prediction unit, and generates three-dimensional modeling data for photo-modeling the model of the artificial nail to be formed by the three-dimensional modeling device; and an output unit that outputs the modeling data to the three-dimensional modeling device;
having
the prediction information is a database in which shape data of the artificial nail, three-dimensional post-curing data indicating an outer shape of a modeled object obtained by photo-modeling and photo-curing after curing, modeling information indicating modeling conditions including the three-dimensional modeling device and a photo-modeling material used for photo-modeling in the three-dimensional modeling device, and applied modeling data , and curing information indicating the curing conditions are stored in association with each other;
Artificial nail manufacturing system. The modeling design device is
an acquisition unit that acquires three-dimensional post-curing data indicating an outer shape after curing of a model that has been photo-modeled and photo-cured based on the modeling data;
an update unit that updates the prediction information based on the hardened data acquired by the acquisition unit, shape data of the artificial nail to be formed based on the hardened data, a prediction result predicted by the prediction unit based on the shape data, and the modeling data generated based on the prediction result;
11. The system for manufacturing an artificial nail according to claim 10, comprising: The modeling design device is
The artificial nail manufacturing system according to claim 10 or 11, further comprising a synthesis unit that synthesizes the modeling data of the plurality of artificial nails to be formed so that the plurality of artificial nails to be formed are arranged on a substrate and integrally formed by the three-dimensional modeling device. The artificial nail manufacturing system according to claim 12, wherein the synthesis unit of the modeling design device includes providing data on the substrate that identifies each of the multiple artificial nails to be formed in an identifiable manner. The artificial nail manufacturing system according to claim 12 or 13, wherein the synthesis unit of the modeling design device synthesizes the modeling data so that a plurality of the substrates, each of which has a plurality of the artificial nails to be formed arranged thereon, are modeled in parallel by the three-dimensional modeling device. The artificial nail manufacturing system according to any one of claims 10 to 14, further comprising an evaluation device having an acquisition unit that acquires three-dimensional post-curing data indicating the external shape of the object after curing from the object after curing light-cured by the curing device, and an evaluation unit that evaluates the object after curing by comparing the post-curing data with shape data of the artificial nail to be formed. The artificial nail manufacturing system according to claim 15, wherein the modeling design device includes an update unit that updates the prediction information based on the evaluation results of the evaluation unit of the evaluation device.