Manufacturing method of three-dimensional structure body and three-dimensional structure body

Abstract

To provide a manufacturing method of a three-dimensional structure body capable of obtaining a three-dimensional structure body which has excellent dimensional accuracy, water resistance, and impact resistance, is free from coloring, and has good color tone.SOLUTION: Provided is a manufacturing method of a three-dimensional structure body which is a cured product of a photocurable composition, wherein the photocurable composition is a photocurable composition (X) including a polymerizable monomer (A) and a polymerizable monomer (B), a glass-transition temperature TA of a homopolymer of the polymerizable monomer (A) is 40°C or over, and a glass-transition temperature TB of a homopolymer of the polymerizable monomer (B) is under 35°C. The manufacturing method includes the following steps of: irradiating first light to the photocurable composition (X) and light-shaping the photocurable composition (X) to obtain a three-dimensional structure body (Y1) in a first cured state; and irradiating second light to the three-dimensional structure body (Y1) and heating at a temperature TC which is lower than TA and higher than TB at a timing at least one step among before, during, and after irradiating the second light to obtain a three-dimensional structure body (Y2) in a second cured state in which curing has been progressed.SELECTED DRAWING: None

Description

[Technical field]

[0001] The present invention relates to a method for producing a three-dimensional structure and a three-dimensional structure. [Background technology]

[0002] A method for manufacturing a three-dimensional object by repeating the steps of supplying a liquid photocurable resin with light energy controlled to a required energy amount to cure it into a thin layer, supplying liquid photocurable resin onto the thin layer cured product, and then supplying similarly controlled light energy to cure it into a thin layer to laminate multiple thin layer cured products is known as the so-called optical photolithography (photolithography).Photolithography is rapidly becoming popular due to its excellent moldability of complex shapes and the fact that it can produce high-precision three-dimensional objects without relying on the skill of the operator.

[0003] A representative method for optically producing a three-dimensional object is known as liquid vat stereolithography, in which the liquid surface of a liquid photocurable resin composition placed in a container is selectively irradiated with a computer-controlled ultraviolet laser so as to obtain the desired pattern, thereby curing the composition to a predetermined thickness and forming a cured layer, and then one layer of liquid photocurable resin composition is supplied on top of the cured layer, which is similarly irradiated with an ultraviolet laser and cured in the same manner as above to form a continuous cured layer. This lamination process is repeated to produce a three-dimensional object in its final shape. Liquid vat stereolithography has attracted much attention in recent years because it can produce a desired three-dimensional object easily and with high accuracy in a relatively short time, even if the object has a fairly complex shape.

[0004] In particular, in the field of dental materials, dental components such as dental mouthpieces and denture bases have different shapes for each individual patient and are complex in shape, so the application of photolithography, including the above-mentioned liquid vat photolithography, is expected.

[0005] Dental mouthpieces include those that are called dental aligners and are worn on the teeth to correct the alignment of teeth, those that are called dental splints and are worn to correct the jaw position, those that are worn on the teeth while sleeping at night to treat sleep apnea syndrome, those that are worn on the teeth to suppress tooth wear caused by teeth grinding, and those that are worn in the oral cavity to reduce trauma caused by the application of large external forces to the teeth and jawbone during contact sports and to protect the stomatognathic system and the brain. The dental mouthpiece is a dental component that has been rapidly expanding in use in recent years due to its good aesthetics in orthodontics and the fact that it can be worn and removed by the wearer himself. Sleep apnea syndrome is also a case that has attracted attention in medical care, and the dental mouthpiece is also rapidly becoming used as a treatment tool for sleep apnea syndrome.

[0006] A denture base is a dental component used on the gums when wearing dentures due to tooth loss. In recent years, the demand for dentures has increased dramatically with the increase in the elderly population, and the demand for denture bases has also increased sharply.

[0007] These dental mouthpieces and denture bases are required to have physical properties such as adaptability to the dentition or alveolar ridge, strength (in other words, water resistance) under appropriate oral moisture conditions, impact resistance, and color tone, but generally, in stereolithography, the photocurable composition is photocured instantly, resulting in an incomplete polymerization state (usually a state in which several percent to several tens of percent of unpolymerized monomer remains, sometimes referred to as a "semi-cured state"), and the modeled object immediately after stereolithography usually does not satisfy the required physical properties. If a modeling is performed by irradiating a strong light to promote polymerization and complete curing, there is a risk of problems such as distortion of the modeled object after curing or peeling between the layers due to weakened bonds between the modeled layers. Therefore, a second light irradiation is performed after modeling using another light irradiator to drive the polymerization and improve the physical properties. Hereinafter, in this specification, the process of further promoting the polymerization of the stereolithography object by such a second light irradiation or the like may be referred to as a "secondary polymerization process." Note that the "secondary polymerization process" may include not only the second light irradiation but also peripheral processes other than the second light irradiation that are performed in parallel with the second light irradiation or at least one of the stages before and after the second light irradiation.

[0008] However, according to the investigations of the present inventors, it was found that when hardening is advanced by carrying out a secondary polymerization step, the obtained three-dimensional structure may not only be deformed, but also may become discolored or have a change in color tone.

[0009] Patent Document 1 describes a method of obtaining a highly accurate model by irradiating a semi-hardened model with light while fitting it to a corresponding working model. However, in recent years, with technological advances in 3D scanners, it has become possible to obtain modeling data using a 3D scanner and perform photo-modeling according to the modeling data, and therefore a modeling process that does not require a model and can perform modeling with high accuracy is required. In addition, Patent Document 1 does not describe the coloring or color change of the model caused by performing a secondary light irradiation, and does not consider how to avoid these problems. [Prior art documents] [Patent documents]

[0010] [Patent Document 1] JP 2018-83300 A Summary of the Invention [Problem to be solved by the invention]

[0011] An object of the present invention is to provide a method for producing a three-dimensional structure that is capable of producing a three-dimensional structure that is excellent in dimensional accuracy, water resistance, and impact resistance, and is free of coloration and has a good color tone. [Means for solving the problem]

[0012] That is, the present invention includes the following inventions. [1] A method for producing a three-dimensional structure that is a cured product of a photocurable composition, comprising the steps of: The photocurable composition is a photocurable composition (X) containing a polymerizable monomer (A) and a polymerizable monomer (B), Glass transition temperature T of homopolymer of polymerizable monomer (A) A is 40°C or higher, The glass transition temperature T of the homopolymer of the polymerizable monomer (B) B is less than 35°C, A method for producing a three-dimensional structure, comprising the following steps (I) and (II): Step (I): A step of photo-modeling the photo-curable composition (X) by subjecting the photo-curable composition (X) to a first light irradiation to obtain a three-dimensional structure (Y1) in a first cured state. Step (II): A second light irradiation is performed on the three-dimensional structure (Y1) in a first cured state, and T is applied in at least one stage selected from the group consisting of before the second light irradiation, during the second light irradiation, and after the second light irradiation. A Lower T B Higher temperature T C A process of obtaining a three-dimensional structure (Y2) in a second cured state in which curing has progressed more than the first cured state by heating the three-dimensional structure (Y2) in a second cured state. [2] The temperature T C The method for producing a three-dimensional structure according to the above [1], wherein the temperature is 35° C. or higher. [3] The method for producing a three-dimensional structure according to the above [1] or [2], wherein the polymerizable monomer (A) contains a polyfunctional polymerizable monomer (A1). [4] The method for producing a three-dimensional structure according to any one of the above [1] to [3], wherein the polymerizable monomer (B) contains a monofunctional polymerizable monomer (B1). [5] A method for producing a three-dimensional structure according to any one of the above [1] to [4], wherein in the step (I), a plate-shaped three-dimensional structure (Y1) is prepared as a test piece according to the dimensions described in JIS T 6501:2012, and the length L0 of the long side in the above dimensions and the length L2 of the long side of the test piece after the step (II) satisfy the following relationship: {|L0-L2| / L0}×100≦1.0 [6] A three-dimensional structure that is a cured product of a photocurable composition, the photocurable composition contains a polymerizable monomer (A) and a polymerizable monomer (B), Glass transition temperature T of homopolymer of polymerizable monomer (A) A is 40°C or higher, The glass transition temperature T of the homopolymer of the polymerizable monomer (B) B is less than 35°C, A three-dimensional structure that satisfies the following conditions (1) and (2). (1) The yellowness index b* measured under a D65 light source in accordance with JIS Z 8722:2009, condition c is 3.0 or less. (2) According to the dimensions described in JIS T 6501:2012, the photocurable composition is photo-shaped by a first light irradiation to prepare a plate-shaped test piece, and the length L0 of the long side in the dimensions is measured. The test piece is subjected to a second light irradiation, and T is measured at least one stage selected from the group consisting of before the second light irradiation, during the second light irradiation, and after the second light irradiation. A Lower T B Higher temperature T C and the length L2 of the long side of the test piece after the treatment object is heated satisfy the following relationship. (|L0-L2| / L0)×100≦1.0 [7] The three-dimensional structure according to [6] above, which satisfies the following condition (3): (3) A plate-shaped test specimen is prepared according to the dimensions described in JIS T 6501:2012, and the bending strength B1 of the test specimen is measured using a universal testing machine at a crosshead speed of 5 mm / min, and the bending strength B2 of the test specimen after immersion in 37°C warm water for 168 hours is measured using a universal testing machine at a crosshead speed of 5 mm / min, and the bending strength B2 satisfies the following relationship. ([B1-B2] / B1)×100≦5.0 [8] The three-dimensional structure according to [6] or [7] above, further satisfying the following condition (4): (4) A plate-shaped test specimen is prepared according to the dimensions described in JIS T 6501:2012, and a φ5 / 8 inch SUS304 steel ball is allowed to fall freely from a height of 40 cm onto the center of the test specimen; the test specimen does not break. Effect of the Invention

[0013] According to the method for producing a three-dimensional structure of the present invention, it is possible to obtain a three-dimensional structure that is excellent in dimensional accuracy, water resistance, and impact resistance, and is free of coloration and has a good color tone. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0014] [Manufacturing method for 3D structures] The method for producing a three-dimensional structure according to an embodiment of the present invention (hereinafter also referred to as the "method for producing a three-dimensional structure according to the present embodiment") is a method for producing a three-dimensional structure which is a cured product of a photocurable composition, comprising the steps of: The photocurable composition is a photocurable composition (X) containing a polymerizable monomer (A) and a polymerizable monomer (B), Glass transition temperature T of homopolymer of polymerizable monomer (A) A is 40°C or higher, The glass transition temperature T of the homopolymer of the polymerizable monomer (B) B is less than 35°C, The method includes the following steps (I) and (II). Step (I): A step of photo-modeling the photo-curable composition (X) by subjecting the photo-curable composition (X) to a first light irradiation to obtain a three-dimensional structure (Y1) in a first cured state (hereinafter, also referred to as a "photo-modeling step"). Step (II): A second light irradiation is performed on the three-dimensional structure (Y1) in a first cured state, and T is applied in at least one stage selected from the group consisting of before the second light irradiation, during the second light irradiation, and after the second light irradiation. A Lower T B Higher temperature T C by heating the object to be treated to obtain a three-dimensional structure (Y2) in a second cured state in which curing has progressed more than the first cured state (hereinafter also referred to as the "secondary polymerization step"). Hereinafter, the three-dimensional structure (Y1) in the first cured state may be simply referred to as "three-dimensional structure (Y1)". Also, the three-dimensional structure (Y2) in the second cured state may be simply referred to as "three-dimensional structure (Y2)".

[0015] In the above-mentioned method for producing a three-dimensional structure, a photocurable composition (X) containing a polymerizable monomer (A) and a polymerizable monomer (B) is used. The glass transition temperature T A Since the glass transition temperature T B Since the temperature is less than 35° C., a flexible structure is introduced into the photocurable composition (X) containing the polymerizable monomer (B). Then, in step (II), the three-dimensional structure (Y1) in the first cured state obtained in step (I) is subjected to a second light irradiation and T A Lower T B Higher temperature T CIt is presumed that by heating at 30° C., a molecular structure with a high glass transition temperature is maintained in the three-dimensional structure (Y1), so that hardening proceeds while preventing deformation, and a three-dimensional structure (Y2) with high dimensional accuracy and excellent water resistance and impact resistance can be obtained. In addition, it is presumed that by going through step (II), mobility is imparted to the molecular structure with a low glass transition temperature in the three-dimensional structure (Y1), improving polymerization, and the generated radicals are easily consumed in the polymerization reaction, suppressing coloration and color change. Hereinafter, each step of the method for producing a three-dimensional structure according to this embodiment will be described.

[0016] <Process (I): Stereolithography process> In the photo-fabrication process, the photo-curable composition (X) is photo-fabricated by performing a first light irradiation on the photo-curable composition (X) based on the modeling data (STL data) to obtain a three-dimensional structure (Y1) in a first cured state. The modeling data can be created using three-dimensional data acquired by a 3D scanner, and the method for producing a three-dimensional structure according to this embodiment can obtain a three-dimensional structure with high dimensional accuracy. Therefore, there is no need to create a model in the photo-fabrication process. Here, the "first cured state" refers to a state in which the three-dimensional structure has been cured to such an extent that it can at least retain the shape of the target structure. The first cured state is a state in which the degree of curing is lower than the "second cured state" described below. The three-dimensional structure (Y1) in the first cured state may have physical properties such as elastic modulus, surface hardness, and toughness, as well as water resistance and impact resistance described below, lower than those of the three-dimensional structure that is substantially completely cured and is ultimately intended to be obtained. The temperature in carrying out step (I) is preferably less than 35°C. There are no particular limitations on the type of photolithography method, but from the viewpoint of ease of producing highly accurate objects, it is preferable to use liquid vat photolithography, in which a three-dimensional structure is formed by selectively irradiating the liquid surface of the photocurable composition with light to form a hardened layer of a predetermined thickness, and then supplying photocurable composition on top of the hardened layer and irradiating it with light to form the next hardened layer, repeating this process. The wavelength of the light irradiated in the stereolithography may be appropriately selected depending on the type of photocurable composition and the type of photopolymerization initiator used, and may be ultraviolet light or visible light. The intensity of the irradiated light and the irradiation time can be appropriately adjusted according to the structure of the target three-dimensional structure, the required accuracy, and the like.

[0017] (stereolithography device) The optical molding apparatus used in the optical molding process is an apparatus that produces a desired object by irradiating light based on molding data that indicates the shape of the object and curing a photocurable composition. The photolithography device is not particularly limited as long as it can produce the three-dimensional structure (Y1) in the first cured state. A LWAX 020D, Perfactry Vida EnvisionTEC's Perfactry Vida) can be used.

[0018] <Step (II): Secondary polymerization step> In the secondary polymerization step, the three-dimensional structure (Y1) in the first cured state is irradiated with a second light, and T is applied at least one of the steps before the second light irradiation, during the second light irradiation, and after the second light irradiation. A Lower T B Higher temperature T C The three-dimensional structure (Y1) is subjected to secondary polymerization by heating at 400 K, thereby obtaining a three-dimensional structure (Y2) in a second cured state in which curing has progressed more than the first cured state. The "second cured state" is preferably a state in which curing is substantially complete. Here, "a state in which curing is substantially complete" means a state in which curing has progressed sufficiently to a degree that satisfies the physical properties required for practical use. Hereinafter, the step of performing the second light irradiation may be referred to as the "secondary irradiation step," and the step of performing heating may be referred to as the "heating step."

[0019] In other words, the secondary polymerization process includes a secondary irradiation process and a heating process, and the secondary irradiation process and the heating process may be performed in an overlapping manner or separately. Examples of combinations of the secondary irradiation process and the heating process in the secondary polymerization process include the following aspects. In the following aspects, "secondary irradiation process and heating process" means that at least a part of the period of the secondary irradiation process and the heating process are performed in parallel. ·(a):Heating process→secondary irradiation process ·(b): Warming process → Secondary irradiation process → Warming process (c): Heating process → Secondary irradiation process and heating process (d): Heating process → Secondary irradiation process and heating process → Heating process (e): Heating process → secondary irradiation process and heating process → secondary irradiation process ·(f):Second irradiation process → heating process ·(g):Second irradiation process → heating process → second irradiation process (h): Secondary irradiation process → Secondary irradiation process and heating process (i): Secondary irradiation process → Secondary irradiation process and heating process → Heating process (j): Secondary irradiation process → Secondary irradiation process and heating process → Secondary irradiation process (k): Secondary irradiation process and heating process (l): Secondary irradiation process and heating process → Heating process (m): Secondary irradiation process and heating process → Secondary irradiation process

[0020] If the secondary irradiation process and the heating process are carried out in parallel for at least a portion of the period, it becomes easier to promote the consumption of radicals generated by the secondary light irradiation, and also possible to shorten the time required for the entire manufacturing process of the three-dimensional structure (Y2). In addition, when moving from the heating process to the secondary irradiation process, the temperature of the processing object itself and the surrounding materials such as the support material of the processing object remain at T B If their temperatures are higher than T B During the period up to the time point described below, the secondary irradiation step and the heating step are essentially performed in parallel. In the above-mentioned secondary irradiation step, the light irradiation may be performed continuously or in a plurality of separate steps. In the former case, the light irradiation can be easily controlled, and in the latter case, the degree of curing can be easily adjusted.

[0021] In the secondary polymerization step, from the viewpoint of easily ensuring high dimensional accuracy, in the step (I), a plate-like three-dimensional structure (Y1) is prepared according to the dimensions described in JIS T 6501:2012 to form a test piece, and it is preferable that the length L0 of the long side in the above dimensions and the length L2 of the long side of the test piece after the step (II) satisfy the following relationship. {|L0-L2| / L0}×100≦1.0 In order to satisfy the above relationship, for example, the conditions of the second light irradiation and the heating time can be appropriately set. In this specification, |L0-L2| / L0 in the above formula is sometimes referred to as "dimensional accuracy."

[0022] (Second irradiation process) The secondary irradiation step is a step of performing a secondary light irradiation on the three-dimensional structure (Y1) in the first cured state to advance the curing. The wavelength of the light to be irradiated may be appropriately selected depending on the type of photocurable composition and the type of photopolymerization initiator used, and may be ultraviolet light or visible light. The intensity, duration and number of times of irradiation of the light to be irradiated can be appropriately adjusted according to the structure of the three-dimensional structure (Y2) to be obtained, the required accuracy, etc. In this case, it is preferable to set the conditions of the irradiation light within a range in which the dimensional accuracy of the three-dimensional structure (Y2) satisfies the above-mentioned relationship.

[0023] (Light irradiation device) The light irradiation device used in the above-mentioned secondary irradiation step is not particularly limited as long as it can promote the curing of the three-dimensional structure (Y1). For example, the light irradiation device may have a table or container for placing the object of the secondary light irradiation inside the device, and irradiate the object placed on the table or container with light from the up-down and left-right directions. The light irradiation device may have a function of switching between short-wavelength light for curing the surface of the object of light irradiation and long-wavelength light for curing the inside of the object of light irradiation. In addition, the light irradiation device may have at least one of a heating function and a nitrogen filling function. As the light irradiation device, a commercially available light irradiation device (for example, Otoflash (registered trademark) G171 manufactured by EnvisionTEC) can be used.

[0024] (Heating process) As described above, the secondary polymerization step includes a heating step, and T A Lower T B Higher temperature T C The object to be treated is heated by the above method. The heating step is preferably carried out during the second light irradiation, or both before and after the second light irradiation, and more preferably during the second light irradiation. In other words, the above modes (b), (d), (k), (l), and (m) are preferred, and modes (k), (l), and (m) are more preferred.

[0025] T C From the viewpoint of easily improving the water resistance of the three-dimensional structure (Y2), the temperature is preferably 35° C. or higher, more preferably 40° C. or higher, even more preferably 50° C. or higher, and even more preferably 60° C. or higher. Also, from the viewpoint of easily improving the dimensional accuracy, impact resistance, and color tone of the three-dimensional structure (Y2), the temperature is preferably 150° C. or lower, more preferably 120° C. or lower, and even more preferably 90° C. or lower. In other words, T C The heating temperature is preferably 35 to 150°C. TC is T A It is preferably 5° C. or more lower, more preferably 10° C. or more lower, and even more preferably 20° C. or more lower than T C is T B It is preferably 5° C. or more higher, more preferably 10° C. or more higher, and even more preferably 20° C. or more higher than the above temperature.

[0026] In addition, the photocurable composition (X) is T A In the case where the polymerizable monomer (A) contains a plurality of types of polymerizable monomers having different values ​​of T c is the lowest T A In addition, the photocurable composition (X) may be set to T B In the case where the polymerizable monomer (B) contains a plurality of types of polymerizable monomers having different values ​​of T c is the highest of these, T B It should be set to the above.

[0027] The heating time is preferably 3 minutes or more, more preferably 5 minutes or more, even more preferably 7 minutes or more, even more preferably 10 minutes or more, and particularly preferably 15 minutes or more, from the viewpoint of easily suppressing discoloration and color change. There is no particular upper limit to the heating time, but from the viewpoint of avoiding deterioration of the three-dimensional structure and production efficiency, it is, for example, 60 minutes or less. In other words, the heating time is preferably 3 to 60 minutes. When heating is performed in multiple periods, it is preferable that the length of each heating period is the above-mentioned time.

[0028] When the secondary irradiation step is performed after the heating step, it is preferable that the time from the end of the heating step to the start of the secondary irradiation step is as short as possible in terms of shortening the overall manufacturing time. For example, the heating step is stopped as close as possible to the secondary irradiation step, so that the temperature of the processing object itself and the temperature of the surrounding members such as the support member of the processing object are kept at T B The time between the heating step and the secondary irradiation step can be made sufficiently close to each other or can be eliminated by starting the secondary light irradiation within the period until the temperature reaches or below 5 minutes, preferably within 5 minutes, more preferably within 1 minute. In addition, when the heating step is performed after the secondary irradiation step, it is preferable that the time from the end of the secondary irradiation step to the start of the heating step is as short as possible in terms of shortening the overall manufacturing time. For example, the start of heating is brought as close as possible to the secondary irradiation step, or heating is started during the secondary irradiation step to keep the temperature of the processing object itself and the temperature of the surrounding members such as the support member of the processing object at T B By keeping the time period close to 10 minutes, the time between the secondary irradiation step and the heating step can be made sufficiently close to each other or can be eliminated. The time period is preferably within 20 minutes, more preferably within 10 minutes.

[0029] (warming device) The heating device for heating in the secondary polymerization step may be built into the light irradiation device, or may be a commercially available thermostatic device. There are no particular limitations on the method of heating, and the object to be treated may be heated directly using a heater or the like, the object to be treated may be placed in a thermostatic chamber and heated, or a light irradiation device may be installed in a thermostatic chamber and the object to be treated may be heated together with the light irradiation device.

[0030] [3D structure] The three-dimensional structure according to an embodiment of the present invention is a three-dimensional structure that is a cured product of a photocurable composition, The photocurable composition contains a polymerizable monomer (A) and a polymerizable monomer (B), Glass transition temperature T of homopolymer of polymerizable monomer (A) A is 40°C or higher, The glass transition temperature T of the homopolymer of the polymerizable monomer (B) B is less than 35°C, The following conditions (1) and (2) are met. (1) The yellowness index b* measured under a D65 light source in accordance with JIS Z 8722:2009, condition c is 3.0 or less. (2) According to the dimensions described in JIS T 6501:2012, the photocurable composition is photo-shaped by a first light irradiation to prepare a plate-shaped test piece, and the length L0 of the long side in the above dimensions is measured. The test piece is subjected to a second light irradiation, and T is measured at least one stage selected from the group consisting of before the second light irradiation, during the second light irradiation, and after the second light irradiation. A Lower T B Higher temperature T C and the length L2 of the long side of the test piece after the object to be treated is heated satisfy the following relationship. (|L0-L2| / L0)×100≦1.0

[0031] The three-dimensional structure according to this embodiment satisfies the above conditions (1) and (2), and has high dimensional accuracy and excellent color tone. The three-dimensional structure (Y2) that satisfies the above relationship can be produced by the above-mentioned method for producing a three-dimensional structure.

[0032] The three-dimensional structure may also satisfy the following condition (3). (3) A plate-shaped test specimen is prepared according to the dimensions described in JIS T 6501:2012, and the bending strength B1 of the test specimen is measured using a universal testing machine at a crosshead speed of 5 mm / min, and the bending strength B2 of the test specimen after immersion in 37°C warm water for 168 hours is measured using a universal testing machine at a crosshead speed of 5 mm / min, and the bending strength B2 satisfies the following relationship. ([B1-B2] / B1)×100≦5.0 When the three-dimensional structure satisfies condition (3), it has excellent water resistance.

[0033] The three-dimensional structure may also satisfy the following condition (4). (4) A plate-shaped test specimen is prepared according to the dimensions specified in JIS T 6501:2012, and when a φ5 / 8 inch SUS304 steel ball is allowed to fall freely from a height of 40 cm onto the center of the test specimen, the test specimen does not break. When the three-dimensional structure satisfies condition (4), it has excellent impact resistance. The three-dimensional structure (Y2) that satisfies the above conditions (3) and (4) can be produced by the above-mentioned method for producing a three-dimensional structure.

[0034] Next, the photocurable composition (X) used in the method for producing the three-dimensional structure will be described.

[0035] <Photocurable composition (X)> The photocurable composition (X) contains a polymerizable monomer (A) and a polymerizable monomer (B). The glass transition temperature T A is 40°C or higher, and the glass transition temperature T B is less than 35°C.

[0036] <Polymerizable monomer (A)> As described above, the glass transition temperature T A is 40°C or higher. A When the temperature is 40° C. or higher, a rigid structure is introduced into the photocurable composition (X) containing the polymerizable monomer (A), and the dimensional accuracy, strength, and water resistance of the cured product of the photocurable composition (X) tend to be excellent. In addition, when the three-dimensional structure (Y2) is assumed to be used as a dental component, T A is 40°C or higher, the structural portion derived from the polymerizable monomer (A) acts like a constraint point in the structure of the three-dimensional structure (Y2) at the oral temperature of around 37°C, and it becomes easier to obtain good impact resistance and water resistance while maintaining high dimensional accuracy of the three-dimensional structure (Y2).

[0037] T A From the viewpoint of ensuring the above-mentioned physical properties, the temperature is preferably 50° C. or higher, more preferably 60° C. or higher, and even more preferably 70° C. or higher. A The upper limit of T is not particularly limited, but from the viewpoint of availability, it is preferably 250° C. or less, more preferably 200° C. or less, and even more preferably 150° C. or less.A The heating temperature is preferably 40 to 250°C, and more preferably 50 to 250°C. The polymerizable monomer (A) may be used alone or in combination of two or more kinds. T A can be measured by a conventional method using a viscoelasticity measuring device (rheometer) or a differential scanning calorimeter (DSC). For example, a rotational rheometer (TA Instruments, "AR2000") is used to measure the dynamic viscoelasticity of a homopolymer of the polymerizable monomer (A). In this dynamic viscoelasticity measurement, the shear rate is set to 10 Hz, and the temperature at which the loss tangent tan δ reaches its peak is determined as the glass transition temperature T A It is also possible to use known literature values ​​(e.g., POLYMER HANDBOOK OF FOURTH EDITION, Volume 1, VI GLASS TRANSITION TEMPERATURE OF POLYMERS, by J. Brandrup, EH Immergut, and EA Grulke, published by WILEY-INTERSVIENCE). In this specification, the glass transition temperature was measured by the method described in the Examples.

[0038] In this specification, the polymerizable monomer means a compound containing a polymerizable group such as a (meth)acryloyl group, a vinyl group, or a styrene group, and may be a monomer, a dimer, or a polymer as long as it contains a polymerizable group. As the polymerizable monomer (A), at least one of a polyfunctional polymerizable monomer (A1) having two or more polymerizable groups and a monofunctional polymerizable monomer (A2) having one polymerizable group can be used. Among them, from the viewpoint of excellent dimensional accuracy and water resistance of the obtained cured product, it is preferable that the polymerizable monomer (A) contains a polyfunctional polymerizable monomer (A1). In this specification, the term "(meth)acrylic" is used to mean both methacryl and acrylic, and the same applies to similar terms such as "(meth)acryloyl" and "(meth)acrylate".

[0039] Examples of the polyfunctional polymerizable monomer (A1) include aliphatic polyfunctional polymerizable monomers having no cyclic structure and polyfunctional polymerizable monomers having a cyclic structure. The cyclic structure is not particularly limited as long as it exhibits the effects of the present invention, and examples thereof include aromatic monocyclic rings such as a benzene ring, a biphenyl ring, and a triphenylmethyl ring; aromatic condensed bicyclic rings such as a naphthalene ring, a pentalene ring, an indene ring, an indane ring, a tetralin ring, and an azulene ring; condensed tricyclic rings such as an as-indacene ring, an s-indacene ring, an acenaphthylene ring, an acenaphthene ring, a fluorene ring, a phenalene ring, a perinaphthene ring, a phenanthrene ring, and an anthracene ring; saturated hydrocarbon rings such as a norbornane ring, a tetracyclododecanyl ring, an adamantane ring, a norbornene ring, a dicyclopentenyl ring, a tricyclododecanyl ring, a cyclopentane ring, a cyclohexane ring, a cycloheptane ring, a cyclooctane ring, and a cyclodecane ring; unsaturated hydrocarbon rings such as a tetralin ring and a fluorene ring; and rings having one nitrogen atom such as a pyrrolidine ring and a piperidine ring. saturated monocyclic rings having two or more nitrogen atoms, such as a piperazine ring, a methenamine ring, an isocyanurate ring, etc.; unsaturated monocyclic rings having one nitrogen atom, such as a pyrrole ring, a pyridine ring, etc.; unsaturated monocyclic rings having two or more nitrogen atoms, such as an imidazole ring, an indazole ring, an imidazoline ring, a pyrazole ring, a pyrazine ring, a pyrimidine ring, a triazole ring, a triazine ring, a tetrazole ring, etc.; unsaturated polycyclic rings having one nitrogen atom, such as an indole ring, an isoindole ring, a quinoline ring, an isoquinoline ring, a carbazole ring, etc.; heterocyclic rings having only a nitrogen atom, such as unsaturated polycyclic rings having two or more nitrogen atoms, such as a benzimidazole ring, a purine ring, a benzotriazole ring, a choline ring, etc.; heterocyclic rings having both a nitrogen atom and an oxygen atom, such as a morpholine ring, a lactam ring, an oxazole ring, a benzoxazine ring, a hydantoin ring, a phthalocyanine ring, etc.Examples of such heterocycles include those having both a nitrogen atom and a sulfur atom, such as a thiazole ring, a thiazine ring, and a phenothiazine ring. Among these, from the viewpoint of excellent dimensional accuracy and water resistance of the stereolithographic object, preferred are aromatic monocycles, aromatic condensed bicycles, carbocyclic condensed tricycles, saturated hydrocarbon rings, saturated monocycles having one nitrogen atom, saturated monocycles having two or more nitrogen atoms, and heterocycles having both a nitrogen atom and an oxygen atom, more preferred are aromatic monocycles, aromatic condensed bicycles, saturated hydrocarbon rings, unsaturated hydrocarbon rings, and saturated monocycles having one nitrogen atom, and more preferred are aromatic monocycles, saturated hydrocarbon rings, unsaturated hydrocarbon rings, saturated monocycles having one nitrogen atom, and saturated monocycles having two or more nitrogen atoms;

[0040] Examples of the polyfunctional polymerizable monomer (A1) include aliphatic polyfunctional polymerizable monomers such as neopentyl glycol di(meth)acrylate, triethylene glycol di(meth)acrylate, dipropylene glycol di(meth)acrylate, tripropylene glycol di(meth)acrylate, dodecane di(meth)acrylate, trimethylolpropane tri(meth)acrylate, pentaerythritol tri(meth)acrylate, pentaerythritol tetra(meth)acrylate, 2,2,4-trimethylhexamethylenebis(2-carbamoyloxyethyl)dimethacrylate (commonly known as UDMA), 2,4-tolylenebis(2-carbamoyloxyethyl)dimethacrylate, and bishydroxyethyl methacrylate-isophorone diurethane, from the viewpoint of excellent dimensional accuracy and water resistance of the stereolithography product. Monomers: aromatic ring-containing polyfunctional polymerizable monomers such as ethoxylated bisphenol A di(meth)acrylate (ethylene oxide (EO) addition number: 2 to 10 mol%), 2,4-tolylene bis(2-carbamoyloxyethyl) dimethacrylate, N,N'-(2,2,4-trimethylhexamethylene) bis[2-(aminocarboxy)propane-1,3-diol] tetramethacrylate, hexamethylene bis{2-carbamoyloxy-3-phenoxypropyl} diacrylate, and 2,4-tolylene bis(2-carbamoyloxyethyl) hexaacrylate; alicyclic polyfunctional polymerizable monomers such as tricyclodecane dimethanol di(meth)acrylate; and heterocycle-containing polyfunctional polymerizable monomers such as tris(2-hydroxyethyl)isocyanurate tri(meth)acrylate. An example of the ethoxylated bisphenol A di(meth)acrylate is one having an ethylene oxide (EO) addition number of 2.6 mol % (sometimes referred to as D2.6E).

[0041] Examples of the monofunctional polymerizable monomer (A2) include an aromatic ring-containing (meth)acrylic acid ester compound, an alicyclic (meth)acrylic acid ester compound, a nitrogen atom-containing cyclic (meth)acrylic acid ester compound, and a cyclic (meth)acrylamide compound.

[0042] Examples of the (meth)acrylic acid ester compound containing an aromatic ring include o-phenylphenol (meth)acrylate, m-phenylphenol (meth)acrylate, p-phenylphenol (meth)acrylate, methoxylated-o-phenylphenol (meth)acrylate, methoxylated-m-phenylphenol (meth)acrylate, methoxylated-p-phenylphenol (meth)acrylate, phenyl (meth)acrylate, 4-biphenylyl (meth)acrylate, 1-naphthyl (meth)acrylate, 2-naphthyl (meth)acrylate, anthryl (meth)acrylate, o-2-propenylphenyl (meth)acrylate, benzhydrol (meth)acrylate, cumylphenol (meth)acrylate, fluorenyl (meth)acrylate, and fluorenylmethyl (meth)acrylate.

[0043] Examples of alicyclic (meth)acrylic acid ester compounds include 2-(1-adamantyl)propyl (meth)acrylate, 2-methyladamantyl-2-yl (meth)acrylate, 2-ethyladamantyl-2-yl (meth)acrylate, 2-n-propyladamantyl-2-yl (meth)acrylate, 2-isopropyladamantyl-2-yl (meth)acrylate, 1-(adamantan-1-yl)-1-methylethyl (meth)acrylate, 1-(adamantan-1-yl)-1-ethylethyl (meth)acrylate, 1-(adamantan-1-yl)-1-methylpropyl (meth)acrylate, and 1-(adamantan-1-yl)-1-ethylpropyl (meth)acrylate.

[0044] Examples of the nitrogen atom-containing cyclic (meth)acrylic acid ester compound include pentamethylpiperidinyl (meth)acrylate, tetramethylpiperidinyl (meth)acrylate, and 4-(pyrimidin-2-yl)piperazin-1-yl (meth)acrylate.

[0045] Examples of cyclic (meth)acrylamide compounds include N-(meth)acryloylmorpholine, N-(meth)acryloylpyrrolidine, N-(meth)acryloylpiperidine, N-(meth)acryloyl-2-methylpiperidine, and N-(meth)acryloyl-2,2,6,6-tetramethylpiperidine.

[0046] The content of the polymerizable monomer (A1) in the polymerizable monomer (A) is preferably from 70 to 100 mass %, more preferably from 75 to 100 mass %, and further preferably from 80 to 100 mass %, from the viewpoints of strength and water resistance. The content of the polymerizable monomer (A2) in the polymerizable monomer (A) is preferably 0 to 30 mass %, more preferably 0 to 25 mass %, and further preferably 0 to 20 mass %, from the viewpoints of strength and viscosity. The ratio of the polymerizable monomer (A1) to the polymerizable monomer (A2) in the photocurable composition (X), in terms of the mass ratio of (A1) / (A2), is preferably 100 / 0 to 70 / 30, more preferably 100 / 0 to 75 / 25, and even more preferably 100 / 0 to 80 / 20. The polymerizable monomer (A) has a higher Tg than the polymerizable monomer (B) and is a hard component, so it is likely to have a stronger effect on the strength of the three-dimensional structure. In addition, the polymerizable monomer (A1) has a high crosslinking property, so it is easy to increase water resistance. Furthermore, the polymerizable monomer (A2) tends to have a relatively small molecular weight, so it is easy to reduce the viscosity of the polymerizable composition and to improve the dimensional accuracy. Therefore, when the ratio of the polymerizable monomer (A1) to the polymerizable monomer (A2) is within the above range, the two are blended in a balanced manner, so that the strength of the obtained three-dimensional structure is ensured, and it is easy to improve the water resistance and dimensional accuracy.

[0047] <Polymerizable monomer (B)> As described above, the glass transition temperature T B is less than 35°C. B When the temperature is less than 35° C., a flexible structure is introduced into the photocurable composition (X) containing the polymerizable monomer (B), making it easier to increase the impact resistance of the cured product of the photocurable composition (X). In addition, when the three-dimensional structure (Y2) is assumed to be used as a dental component, T B is less than 35°C, the polymerizable monomer (B) can contain a structure that is softened at the oral temperature of around 37°C in the three-dimensional structure (Y2), and the molded object can have excellent impact resistance. The polymerizable monomer (B) may contain a polyfunctional polymerizable monomer (B1), may contain a monofunctional polymerizable monomer (B2), or may contain a polyfunctional polymerizable monomer (B1) and a monofunctional polymerizable monomer (B2). It is preferable to contain both the polyfunctional polymerizable monomer (B1) and the monofunctional polymerizable monomer (B2) because the impact resistance and viscosity tend to be excellent.

[0048] The glass transition temperature T of the homopolymer of the polymerizable monomer (B) B is less than 35°C. B When the temperature is less than 35°C, a flexible structure is introduced into the photocurable composition (X) containing the polymerizable monomer (B), and the dimensional accuracy and impact resistance of the cured product of the photocurable composition (X) tend to be excellent. T B From the viewpoint of ensuring the above-mentioned physical properties, the temperature is preferably 25° C. or lower, more preferably 15° C. or lower, and even more preferably 5° C. or lower. B The lower limit of T is not particularly limited, but from the viewpoint of availability, it is preferably −100° C. or higher, more preferably −80° C. or higher, and even more preferably −60° C. or higher. B is preferably -100 ° C ≦ T B <35°C, and more preferably -100°C to +25°C. The polymerizable monomer (B) may be used alone or in combination of two or more kinds. B is T A can be measured in the same manner.

[0049] Examples of the polyfunctional polymerizable monomer (B1) include polyfunctional polymerizable monomers such as polybutylene glycol di(meth)acrylate, polypropylene glycol di(meth)acrylate, polybutylene glycol di(meth)acrylate, polybutadiene glycol di(meth)acrylate, hydrogenated polybutadiene glycol di(meth)acrylate, polyisoprene glycol di(meth)acrylate, hydrogenated isoprene glycol di(meth)acrylate, and urethane (meth)acrylate oligomers. Examples of the urethane (meth)acrylate oligomer include polyester-based urethane (meth)acrylate oligomers, polycarbonate-based urethane (meth)acrylate oligomers, polyurethane-based urethane (meth)acrylate oligomers, polyether-based urethane (meth)acrylate oligomers, polyconjugated diene-based urethane (meth)acrylate oligomers, and hydrogenated polyconjugated diene-based urethane (meth)acrylate oligomers.

[0050] Examples of the monofunctional polymerizable monomer (B2) include an aromatic ring-containing (meth)acrylic acid ester compound and an aliphatic (meth)acrylic acid ester compound.

[0051] Examples of the (meth)acrylic acid ester compound containing an aromatic ring include ethoxylated-o-phenylphenol (meth)acrylate, ethoxylated-m-phenylphenol (meth)acrylate, ethoxylated-p-phenylphenol (meth)acrylate, propoxylated-o-phenylphenol (meth)acrylate, propoxylated-m-phenylphenol (meth)acrylate, propoxylated-p-phenylphenol (meth)acrylate, butoxylated-o-phenylphenol (meth)acrylate, butoxylated-m-phenylphenol (meth)acrylate, butoxylated-p-phenylphenol (meth)acrylate, o-phenoxybenzyl (meth)acrylate, m- Examples of the acrylates include phenoxybenzyl (meth)acrylate, p-phenoxybenzyl (meth)acrylate, 2-(o-phenoxyphenyl)ethyl (meth)acrylate, 2-(m-phenoxyphenyl)ethyl (meth)acrylate, 2-(p-phenoxyphenyl)ethyl (meth)acrylate, 3-(o-phenoxyphenyl)propyl (meth)acrylate, 3-(m-phenoxyphenyl)propyl (meth)acrylate, 3-(p-phenoxyphenyl)propyl (meth)acrylate, 4-(o-phenoxyphenyl)butyl (meth)acrylate, 4-(m-phenoxyphenyl)butyl (meth)acrylate, and 4-(p-phenoxyphenyl)butyl (meth)acrylate. Examples of the aliphatic (meth)acrylic acid ester compound include undecyl (meth)acrylate, lauryl (meth)acrylate, tridecyl (meth)acrylate, tetradecyl (meth)acrylate, pentadecyl (meth)acrylate, cetyl (meth)acrylate, palmitoleic (meth)acrylate, heptadecyl (meth)acrylate, oleyl (meth)acrylate, and isostearyl (meth)acrylate.

[0052] The content of the polymerizable monomer (B1) in the polymerizable monomer (B) is preferably 0 to 30 mass %, more preferably 0 to 25 mass %, and further preferably 0 to 20 mass %, from the viewpoints of impact resistance and water resistance. The content of the polymerizable monomer (B2) in the polymerizable monomer (B) is preferably 70 to 100 mass%, more preferably 80 to 100 mass%, and even more preferably 90 to 100 mass%, from the viewpoints of impact resistance and viscosity. The ratio of the polymerizable monomer (B1) to the polymerizable monomer (B2) in the photocurable composition (X), in terms of the mass ratio (B1) / (B2), is preferably 30 / 70 to 0 / 100, more preferably 25 / 75 to 0 / 100, and even more preferably 20 / 80 to 0 / 100. The polymerizable monomer (B) has a lower Tg than the polymerizable monomer (A) and is a soft component, so it is likely to have a stronger effect on the flexibility and impact resistance of the three-dimensional structure. In addition, the polyfunctional polymerizable monomer (B1) has high crosslinkability, so it is easy to increase water resistance. Furthermore, the monofunctional polymerizable monomer (B2) tends to have a relatively small molecular weight, so it is easy to reduce the viscosity of the polymerizable composition and to improve the dimensional accuracy. Therefore, when the ratio of the polyfunctional polymerizable monomer (B1) and the monofunctional polymerizable monomer (B2) is within the above range, the two are blended in a balanced manner, so that the impact resistance of the obtained three-dimensional structure is ensured, and the water resistance and dimensional accuracy are easily improved.

[0053] When a polymer is used as the polymerizable monomer (B1), the weight average molecular weight (Mw) thereof is, from the viewpoints of impact resistance and viscosity, preferably 400 to 10,000, more preferably 400 to 7,500, further preferably 600 to 5,000, and particularly preferably 800 to 3,000. In this specification, the weight average molecular weight (Mw) means the weight average molecular weight in terms of polystyrene determined by gel permeation chromatography (GPC).

[0054] <Other polymerizable monomers> The photocurable composition (X) may or may not contain a polymerizable monomer other than the polymerizable monomer (A) and the polymerizable monomer (B). An example of the polymerizable monomer other than the polymerizable monomer (A) and the polymerizable monomer (B) is n-stearyl methacrylate (Tg=38° C.).

[0055] The total content of the polymerizable monomer (A) and the polymerizable monomer (B) in the photocurable composition (X) is preferably 70 parts by mass or more, more preferably 80 parts by mass or more, even more preferably 90 parts by mass or more, and even more preferably 95 parts by mass or more, based on 100 parts by mass of the total amount of the polymerizable monomer (A), the polymerizable monomer (B) and other polymerizable monomers, from the viewpoint of making it easier to enhance each of the above physical properties. There is no particular limit to the upper limit, and it may be 100 parts by mass, or from the viewpoint of ease of production, it may be, for example, 99 parts by mass or less, or 98 parts by mass or less.

[0056] The mass M of the polymerizable monomer (A) contained in the photocurable composition (X) A and the mass M of the polymerizable monomer (B) B The ratio M A / M B From the viewpoint of easily ensuring the above-mentioned physical properties in a well-balanced manner, the ratio is preferably 50 / 50 to 85 / 15, more preferably 55 / 45 to 80 / 20, and even more preferably 60 / 40 to 75 / 25.

[0057] <Photopolymerization initiator (C)> The photocurable composition (X) preferably contains a photopolymerization initiator (C). The photopolymerization initiator (C) can be selected from photopolymerization initiators used in general industry, and among them, photopolymerization initiators used for dental purposes are preferred.

[0058] Examples of the photopolymerization initiator (C) include (bis)acylphosphine oxides, thioxanthones or quaternary ammonium salts of thioxanthones, ketals, α-diketones, coumarins, anthraquinones, benzoin alkyl ether compounds, α-aminoketone compounds, etc. The photopolymerization initiator (C) may be used alone or in combination of two or more kinds.

[0059] Among them, it is preferable to use at least one selected from the group consisting of (bis)acylphosphine oxides and α-diketones, and (bis)acylphosphine oxides are preferable, which provides a photopolymerizable composition that is excellent in photocurability in the ultraviolet and visible light regions and exhibits sufficient photocurability when any of the light sources, such as a laser, a halogen lamp, a light-emitting diode (LED), and a xenon lamp, is used.

[0060] Among the (bis)acylphosphine oxides, examples of the acylphosphine oxides include 2,4,6-trimethylbenzoyldiphenylphosphine oxide, 2,6-dimethoxybenzoyldiphenylphosphine oxide, 2,6-dichlorobenzoyldiphenylphosphine oxide, 2,4,6-trimethylbenzoylmethoxyphenylphosphine oxide, 2,4,6-trimethylbenzoylethoxyphenylphosphine oxide, 2,3,5,6-tetramethylbenzoyldiphenylphosphine oxide, benzoyldi(2,6-dimethylphenyl)phosphonate, 2,4,6-trimethylbenzoylphenylphosphine oxide sodium salt, 2,4,6-trimethylbenzoylphenylphosphine oxide potassium salt, and 2,4,6-trimethylbenzoyldiphenylphosphine oxide ammonium salt. Examples of bisacylphosphine oxides include bis(2,6-dichlorobenzoyl)phenylphosphine oxide, bis(2,6-dichlorobenzoyl)-2,5-dimethylphenylphosphine oxide, bis(2,6-dichlorobenzoyl)-4-propylphenylphosphine oxide, bis(2,6-dichlorobenzoyl)-1-naphthylphosphine oxide, bis(2,6-dimethoxybenzoyl)phenylphosphine oxide, bis(2,6-dimethoxybenzoyl)-2,4,4-trimethylpentylphosphine oxide, bis(2,6-dimethoxybenzoyl)-2,5-dimethylphenylphosphine oxide, bis(2,4,6-trimethylbenzoyl)phenylphosphine oxide, bis(2,5,6-trimethylbenzoyl)-2,4,4-trimethylpentylphosphine oxide, etc. Furthermore, compounds described in JP-A-2000-159621 can be mentioned.

[0061] Among these (bis)acylphosphine oxides, it is particularly preferable to use 2,4,6-trimethylbenzoyldiphenylphosphine oxide, 2,4,6-trimethylbenzoylmethoxyphenylphosphine oxide, bis(2,4,6-trimethylbenzoyl)phenylphosphine oxide, and 2,4,6-trimethylbenzoylphenylphosphine oxide sodium salt as the photopolymerization initiator (C).

[0062] Examples of α-diketones include diacetyl, benzyl, camphorquinone, 2,3-pentadione, 2,3-octadione, 9,10-phenanthrenequinone, 4,4′-oxybenzyl, and acenaphthenequinone. Among these, camphorquinone is particularly preferred when a light source in the visible light range is used.

[0063] The content of the photopolymerization initiator (C) in the photocurable composition (X) is not particularly limited, but from the viewpoint of the curability of the obtained photocurable resin composition, the photopolymerization initiator (C) is preferably 0.01 to 20 parts by mass relative to 100 parts by mass of the total amount of the polymerizable monomer (A), the polymerizable monomer (B) and other polymerizable monomers. If the content of the photopolymerization initiator (C) is 0.01 parts by mass or more, polymerization proceeds sufficiently, and it becomes easy to obtain a photo-shaped object. The content of the photopolymerization initiator (C) is more preferably 0.05 parts by mass or more, further preferably 0.1 parts by mass or more, and particularly preferably 0.5 parts by mass or more relative to the total amount of 100 parts by mass. On the other hand, if the content of the photopolymerization initiator (C) is 20 parts by mass or less, precipitation from the photocurable composition is unlikely to occur even if the solubility of the polymerization initiator itself is low. The content of the photopolymerization initiator (C) is more preferably 15 parts by mass or less, further preferably 10 parts by mass or less, and particularly preferably 5.0 parts by mass or less, relative to the total amount of 100 parts by mass.

[0064] <Other ingredients> The photocurable composition (X) may further contain one or more other components within a range that does not impair the effects of the present invention. For example, a polymerization inhibitor, a sensitizer or chain transfer agent for use in combination with the photopolymerization initiator, an oxygen quencher, etc. may be further blended. In addition, known additives can be blended for the purpose of adjusting the mechanical properties and viscosity of the composition. Examples of such additives include inorganic particles, organic particles, organic solvents, and thickeners. The blending amount of other components is not particularly limited, and from the viewpoint of easily obtaining the required effects, it is preferably 0.01 to 5.0 parts by mass, more preferably 0.05 to 3.0 parts by mass, and even more preferably 0.1 to 2.0 parts by mass, per 100 parts by mass of the photocurable composition (X). EXAMPLES

[0065] Next, the present invention will be described in more detail with reference to examples. However, the present invention is not limited to these examples, and many modifications can be made by those having ordinary skill in the art within the scope of the technical concept of the present invention.

[0066] Each component used in the photocurable composition according to the Examples and Comparative Examples will be explained below together with its abbreviation.

[0067] [T A (A1) a polyfunctional polymerizable monomer having a temperature of 40° C. or higher] UDMA: 2,2,4-trimethylhexamethylenebis(2-carbamoyloxyethyl)dimethacrylate (manufactured by Kyoeisha Chemical Co., Ltd., T A = 95℃) D2.6E: 2,2-bis(4-methacryloyloxypolyethoxyphenyl)propane (average number of moles of ethoxy groups added: 2.6) ("BPE-100" manufactured by Shin-Nakamura Chemical Co., Ltd., T A = 85℃)

[0068] [T A (A2) Monofunctional polymerizable monomer having a temperature of 40° C. or higher] PMPMA: Pentamethylpiperidinyl methacrylate (manufactured by ADEKA Corporation, liquid, T A = 105℃)

[0069] [T B (B2) a monofunctional polymerizable monomer having a temperature of less than 35°C. EPPA: Ethoxylated o-phenylphenol acrylate (Shin-Nakamura Chemical Co., Ltd., A-LEN-10, T B =33℃)

[0070] [Photopolymerization initiator (C)] ·TPO: 2,4,6-trimethylbenzoyldiphenylphosphine oxide BAPO: Bis(2,4,6-trimethylbenzoyl)phenylphosphine oxide

[0071] [Polymerization inhibitor] BHT: 3,5-di-t-butyl-4-hydroxytoluene

[0072] <Synthesis example 1:T B Production of polyfunctional polymerizable monomer (B1)-1 having a polymerization temperature of less than 35° C. Into a 5 L four-neck flask (1) equipped with a stirrer, a temperature controller, a thermometer, and a condenser, 250 g of isophorone diisocyanate and 0.15 g of di-n-butyltin dilaurate were added and heated to 70° C. with stirring. On the other hand, 2,500 g of polyester polyol ("Kuraray Polyol (registered trademark) P-2050" manufactured by Kuraray Co., Ltd.; polyol consisting of sebacic acid and 3-methyl-1,5-pentanediol, weight average molecular weight Mw 2,000) was added to a dropping funnel equipped with a side tube, and the liquid in this dropping funnel was dropped into the flask (1) above. The solution in the flask (1) above was stirred while the internal temperature of the flask was maintained at 65 to 75°C and dropped at a constant rate over 4 hours. After the dropwise addition was completed, the mixture was stirred at the same temperature for 2 hours to react. Next, a solution in which 150 g of 2-hydroxyethyl acrylate and 0.4 g of hydroquinone monomethyl ether had been uniformly dissolved in another dropping funnel was added dropwise at a constant rate over a period of 2 hours while maintaining the internal temperature of the flask at 55-65°C, and then the solution was reacted for 4 hours while maintaining the temperature of the solution in the flask at 70-80°C, thereby obtaining a polyfunctional polymerizable monomer (B1)-1. The weight average molecular weight Mw of the polyfunctional polymerizable monomer (B1)-1 according to GPC analysis was 2,600, and the glass transition temperature T of the homopolymer of the polyfunctional polymerizable monomer (B1)-1 was 1.018. B was -30℃.

[0073] <Measurement of glass transition temperature> A homopolymer of each of the above polymerizable monomers was prepared, and the dynamic viscoelasticity of each homopolymer was measured using a rotational rheometer (TA Instruments, "AR2000") In this dynamic viscoelasticity measurement, the shear rate was set to 10 Hz, and the temperature at which the loss tangent tan δ reached its peak was determined as the glass transition temperature of each homopolymer.

[0074] <Measurement of weight average molecular weight> The weight average molecular weight of the polymerizable monomer was calculated as a polystyrene equivalent value using gel permeation chromatography (GPC).

[0075] <Reference Example 1: Preparation of photocurable composition (X)-1> 650 parts by mass of UDMA, 50 parts by mass of polyfunctional polymerizable monomer (B1)-1, 300 parts by mass of EPPA, 20 parts by mass of TPO, and 5.0 parts by mass of BHT were placed in a 2L brown wide-mouth polyethylene bottle, and a mechanical stirrer was inserted and the mixture was stirred at 50° C. for 6 hours to confirm complete dissolution. The resulting composition was designated photocurable composition (X)-1.

[0076] <Reference Example 2: Preparation of photocurable composition (X)-2> In a 2L brown wide-mouth polyethylene bottle, 650 parts by mass of D2.6E, 50 parts by mass of polyfunctional polymerizable monomer (B1)-1, 300 parts by mass of EPPA, 20 parts by mass of TPO, and 5.0 parts by mass of BHT were placed, and a mechanical stirrer was inserted and the mixture was stirred at 50°C for 6 hours to confirm complete dissolution. The resulting composition was designated photocurable composition (X)-2.

[0077] <Reference Example 3: Preparation of photocurable composition (X)-3> 600 parts by mass of UDMA, 100 parts by mass of PMPMA, 300 parts by mass of EPPA, 20 parts by mass of TPO, and 5.0 parts by mass of BHT were placed in a 2 L brown wide-mouth polyethylene bottle, and a mechanical stirrer was inserted and the mixture was stirred at 50° C. for 6 hours to confirm complete dissolution. The resulting composition was designated photocurable composition (X)-3.

[0078] <Reference Example 4: Preparation of photocurable composition (X)-4> 650 parts by mass of UDMA, 300 parts by mass of EPPA, 20 parts by mass of BAPO, and 5.0 parts by mass of BHT were placed in a 2 L brown wide-mouth polyethylene bottle, and a mechanical stirrer was inserted and the mixture was stirred at 50° C. for 6 hours to confirm complete dissolution. The resulting composition was designated photocurable composition (X)-4. Table 1 shows the compositions of the photocurable compositions (X)-1 to (X)-4.

[0079] [Table 1]

[0080] [Example 1] The photocurable composition (X)-1 was photo-modeled using a photo-modeling machine (DIGITALWAX (registered trademark) 020D manufactured by DWS) according to the dimensional data of the test piece described later. The obtained photo-modeled object was washed with ethanol to remove the unpolymerized polymerizable monomer adhering thereto, and a test piece in a first cured state was obtained. The test piece was placed in a thermostatic chamber at 40°C and heated for 20 minutes, and then immediately removed and irradiated with light 2,000 times for 3.5 minutes at 25°C as the second light irradiation using a light irradiator (Otoflash (registered trademark) G171 manufactured by EnvisionTEC). Then, the test piece was immediately placed in a thermostatic chamber at 40°C and heated for 20 minutes to complete the secondary polymerization process, and a three-dimensional structure was obtained. In this embodiment, the test piece reached 40°C about 10 minutes after being placed in the thermostatic chamber, so the total heating time at 40°C was 20 minutes, which was 10 minutes before the light irradiation plus 10 minutes after the light irradiation.

[0081] [Example 2] A three-dimensional structure was obtained in the same manner as in Example 1, except that the heating temperatures before and after the second light irradiation were both set to 60° C. In this example, the test piece reached 60° C. about 10 minutes after being placed in the thermostatic chamber, so the total heating time at 60° C. was 20 minutes, which was the sum of 10 minutes before light irradiation and 10 minutes after light irradiation.

[0082] [Example 3] A three-dimensional structure was obtained in the same manner as in Example 1, except that the heating temperatures before and after the second light irradiation were both set to 80° C. In this example, the test piece reached 80° C. about 10 minutes after being placed in the thermostatic chamber, and the total heating time at 80° C. was 20 minutes, which was the sum of 10 minutes before light irradiation and 10 minutes after light irradiation.

[0083] [Example 4] A three-dimensional structure was obtained in the same manner as in Example 1, except that the test piece in the first cured state of Example 1 was placed in a 60°C thermostatic chamber, and after 20 minutes had passed, the second light irradiation was started in the thermostatic chamber, and after the second light irradiation was completed, the test piece was immediately removed, thereby simultaneously carrying out heating and the second light irradiation. In this example, the test piece reached 60°C about 10 minutes after being placed in the thermostatic chamber, so the total heating time to 60°C was 13.5 minutes, which was the sum of 10 minutes before light irradiation and 3.5 minutes during light irradiation.

[0084] [Example 5] A three-dimensional structure was obtained in the same manner as in Example 1, except that the heating temperatures before and after the second light irradiation were both set to 60°C, and the photocurable composition (X)-1 was changed to the photocurable composition (X)-2. In this example, the test piece reached 60°C about 10 minutes after being placed in the thermostatic chamber, so the total heating time at 60°C was 20 minutes, which was the sum of 10 minutes before light irradiation and 10 minutes after light irradiation.

[0085] [Example 6] A three-dimensional structure was obtained in the same manner as in Example 1, except that the heating temperatures before and after the second light irradiation were both set to 60°C, and the photocurable composition (X)-1 was changed to the photocurable composition (X)-3. In this example, the test piece reached 60°C about 10 minutes after being placed in the thermostatic chamber, so the total heating time at 60°C was 20 minutes, which was the sum of 10 minutes before light irradiation and 10 minutes after light irradiation.

[0086] [Example 7] A three-dimensional structure was obtained in the same manner as in Example 1, except that heating was performed only before the second light irradiation, and the heating temperature was set to 60° C. In this example, the test piece reached 60° C. about 10 minutes after being placed in the thermostatic chamber, so the heating time to 60° C. was 10 minutes.

[0087] [Example 8] A three-dimensional structure was obtained in the same manner as in Example 1, except that heating was performed only after the second light irradiation, and the heating temperature was set to 60° C. In this example, the test piece reached 60° C. about 10 minutes after being placed in the thermostatic chamber, so the heating time to 60° C. was 10 minutes.

[0088] [Example 9] A three-dimensional structure was obtained in the same manner as in Example 1, except that the photocurable composition (X)-1 was changed to the photocurable composition (X)-4, and the heating temperature was changed to 60° C. In this example, the test piece reached 60° C. about 10 minutes after being placed in the thermostatic chamber, and therefore the total heating time at 60° C. was 20 minutes, which was the sum of 10 minutes before light irradiation and 10 minutes after light irradiation.

[0089] [Comparative Example 1] A three-dimensional structure was obtained in the same manner as in Example 1, except that the heating temperature before and after light irradiation was 30°C, and the photocurable composition (X)-1 was changed to the photocurable composition (X)-3. In this comparative example, the test piece reached 30°C about 10 minutes after being placed in the thermostatic chamber, so the total heating time at 30°C was 20 minutes, which was the sum of 10 minutes before light irradiation and 10 minutes after light irradiation.

[0090] [Comparative Example 2] A three-dimensional structure was obtained in the same manner as in Example 1, except that the heating temperature before and after light irradiation was 120° C. In this comparative example, the test piece reached 120° C. about 10 minutes after being placed in the thermostatic chamber, so the total heating time at 120° C. was 20 minutes, which was the sum of 10 minutes before light irradiation and 10 minutes after light irradiation.

[0091] [Comparative Example 3] A three-dimensional structure was obtained in the same manner as in Example 1, except that the second light irradiation was performed in an environment of 25° C. without heating, and the number of light irradiations was 4,000.

[0092] <Dimensional accuracy> The photocurable compositions of Reference Examples 1 to 4 were subjected to a stereolithography using a stereolithography machine (DIGIT AUsing LWAX (registered trademark) 020D, stereolithography was performed according to the dimensions (length 64.0 mm, width 10.0 mm, thickness 3.3 mm) specified in JIS T 6501:2012 (acrylic resin for denture bases), and five plate-shaped stereolithography objects were produced. The obtained stereolithography objects were washed with ethanol to remove unpolymerized polymerizable monomers, and then secondary polymerization (secondary light irradiation and heating) was performed according to the procedures described in each Example and Comparative Example to obtain test pieces. The dimension (unit: mm) of the long side of the test piece was measured using a vernier caliper, the length of the long side in the dimensions specified in the JIS standard was taken as L0, the measured dimension of the test piece was taken as L2, and the dimensional accuracy was calculated using the following formula. If the value of the dimensional accuracy measured and calculated by this method is 1.0% or less, the dimensional accuracy is excellent, and when a dental mouthpiece, denture base, etc. are formed, they are likely to have excellent compatibility. Dimensional accuracy (%) = (|L0-L2| / L0) x 100

[0093] <Water resistance> Ten test pieces were prepared using the same procedure as in the measurement of dimensional accuracy described above, and five of them were stored in air for one day and then subjected to a bending strength test for evaluation. The bending strength test was performed using a universal testing machine (Shimadzu Corporation, Autograph AG-I 100kN) at a crosshead speed of 5mm / min. The arithmetic average value of the five measured values ​​was taken as the initial value B1. The results are shown in Table 2 as "initial bending strength." The bending strength of the test piece is preferably 70 MPa or more, and more preferably 80 MPa or more. The remaining five test pieces were immersed in 37°C warm water for 168 hours, and then their bending strength was measured. The arithmetic mean value of the five measured values ​​was taken as the bending strength B2 after the water resistance test. The results are shown in Table 2 as "Bending strength after immersion". If the rate of change (decrease rate) of bending strength B2 after 168 hours of immersion in 37°C water relative to the initial bending strength B1 is 5% or less, it can be determined that the three-dimensional structure has excellent water resistance. In Table 2, the rate of change in bending strength calculated by the following formula is shown as "water resistance". Bending strength change rate (decrease rate) (%) = ([B1-B2] / B1) x 100

[0094] <Impact resistance> A test piece was prepared using the same procedure as in the measurement of dimensional accuracy described above. The test piece of the photocurable composition according to each Example and Comparative Example was placed in a universal testing machine in the same manner as in the bending test, and a φ5 / 8 inch SUS304 steel ball was allowed to freely fall from a height of 40 cm to impact the center of the test piece. It is preferable that the test piece does not break in this test. When the cured product did not break, the impact resistance was rated as good "G", and when the cured product broke, the impact resistance was rated as poor "NG".

[0095] <color tone> For the photocurable composition of each Reference Example, a disk-shaped stereolithography object with a diameter of 15.0 mm and a thickness of 1.0 mm was produced using the stereolithography machine. The stereolithography object obtained was washed with ethanol to remove unpolymerized polymerizable monomers, and then a three-dimensional structure was obtained by performing secondary polymerization (secondary light irradiation and heating) using a photoirradiator (Otoflash (registered trademark) G171 manufactured by EnvisionTEC) in the procedure described in each Example and Comparative Example. The obtained three-dimensional structure was polished with silicon carbide paper No. 1000, and then polished with dental wrapping film (manufactured by 3M), and then the yellowness index b was measured using a spectrophotometer (SPECTROPHOTOMETER CM-3610A manufactured by Konica Minolta, Inc., compliant with JIS Z 8722:2009, condition c, D65 light source). * The values ​​were measured and the arithmetic mean values ​​were obtained (n=5). The mean values ​​are shown in Table 2. If the yellowness index b* value is 3.0 or less, when dental components such as dental mouthpieces and denture bases are produced, they are likely to be visually recognized as colorless.

[0096] [Table 2]

[0097] From Table 2, it can be seen that the three-dimensional structures manufactured by the methods of Examples 1 to 9 are excellent in dimensional accuracy, water resistance, impact resistance, and color tone. In particular, the water resistance and color tone of the three-dimensional structures manufactured by the methods of Examples 1 to 9 are excellent at the heating temperature T Cis the glass transition temperature T of the homopolymer of the polymerizable monomer (B) B It is clear that this is superior to the three-dimensional structure produced by the method of Comparative Example 1, which has a lower value. The dimensional accuracy and impact resistance of the three-dimensional structures produced by the methods of Examples 1 to 9 were measured at a heating temperature T C is the glass transition temperature T of the homopolymer of the polymerizable monomer (A). A It is clear that this is superior to the three-dimensional structure produced by the method of Comparative Example 2, which has a higher density. It is also clear that the water resistance, impact resistance, and color tone of the three-dimensional structures produced by the methods of Examples 1 to 9 are superior to those of the three-dimensional structure produced by the method of Comparative Example 3 in which no heating is performed. [Industrial Applicability]

[0098] The method for producing a three-dimensional structure of the present invention can obtain a three-dimensional structure (Y2) that is excellent in dimensional accuracy, water resistance, and impact resistance, and has good color tone without coloring. Therefore, the method is suitable for applications where high accuracy, water resistance, impact resistance, and aesthetics are required for the three-dimensional structure, and can be particularly suitably used for producing dental mouthpieces and denture bases.

Claims

1. A method for producing a three-dimensional structure that is a cured product of a photocurable composition, comprising: the photocurable composition is a photocurable composition (X) containing a polymerizable monomer (A) and a polymerizable monomer (B), The glass transition temperature T of the homopolymer of the polymerizable monomer (A) Ａ is 40°C or higher, The glass transition temperature T of the homopolymer of the polymerizable monomer (B) Ｂ is less than 35°C, A method for producing a three-dimensional structure, comprising the following steps (I) and (II): Step (I): A step of subjecting the photocurable composition (X) to primary light irradiation to stereolithography the photocurable composition (X) to obtain a three-dimensional structure (Y1) in a first cured state. Step (II): The three-dimensional structure (Y1) in the first cured state is subjected to a second light irradiation, and T is applied in at least one stage selected from the group consisting of before the second light irradiation, during the second light irradiation, and after the second light irradiation. Ａ Lower T Ｂ Higher temperature T Ｃ a step of obtaining a three-dimensional structure (Y2) in a second cured state in which curing has progressed more than in the first cured state by heating the mixture at

2. The temperature T Ｃ The method for producing a three-dimensional structure according to claim 1, wherein the temperature is 35°C or higher.

3. The method for producing a three-dimensional structure according to claim 1 or 2, wherein the polymerizable monomer (A) contains a polyfunctional polymerizable monomer (A1).

4. The method for producing a three-dimensional structure according to claim 1 or 2, wherein the polymerizable monomer (B) contains a monofunctional polymerizable monomer (B1).

5. In the step (I), a plate-shaped three-dimensional structure (Y1) is prepared according to the dimensions described in JIS T 6501:2012 to form a test piece, and the length L of the long side in the dimensions is ０ and the length L of the long side of the test piece after the step (II) is performed. ２ The method for manufacturing a three-dimensional structure according to claim 1 or 2, wherein the following relationship is satisfied: {|L ０ -L ２ | / L ０ }×100≦1.0

6. A three-dimensional structure that is a cured product of a photocurable composition, the photocurable composition contains a polymerizable monomer (A) and a polymerizable monomer (B), The glass transition temperature T of the homopolymer of the polymerizable monomer (A) Ａ is 40°C or higher, The glass transition temperature T of the homopolymer of the polymerizable monomer (B) Ｂ is below 35°C, A three-dimensional structure that satisfies the following conditions (1) and (2): (1) The yellowness index b* measured under a D65 light source in accordance with JIS Z 8722:2009, condition c, is 3.0 or less. (2) According to the dimensions described in JIS T 6501:2012, the photocurable composition is subjected to primary light irradiation to produce a plate-shaped test piece, and the length L of the long side in the dimensions is ０ and performing a second light irradiation on the test piece, and performing T in at least one stage selected from the group consisting of before the second light irradiation, during the second light irradiation, and after the second light irradiation. Ａ Lower T Ｂ Higher temperature T Ｃ The length L of the long side of the test piece after heating the object to be treated ２ and satisfy the following relationship: ・(|L ０ -L ２ | / L ０ )×100≦1.0

7. The three-dimensional structure according to claim 6, which satisfies the following condition (3): (3) A plate-shaped test piece was prepared using the photocurable composition according to the dimensions described in JIS T 6501:2012, and the bending strength B of the test piece was measured using a universal testing machine at a crosshead speed of 5 mm / min. １ and the bending strength B of the test piece after immersion in warm water at 37°C for 168 hours, measured using a universal testing machine at a crosshead speed of 5 mm / min. ２ and satisfy the following relationship: ・([B １ -B ２ ] / B １ )×100≦5.0

8. The three-dimensional structure according to claim 6 or 7, further satisfying the following condition (4): (4) A plate-shaped test specimen is prepared using the photocurable composition according to the dimensions described in JIS T 6501:2012, and a φ5 / 8 inch SUS304 steel ball is allowed to freely drop from a height of 40 cm onto the center of the test specimen, but the test specimen does not break.