Method for manufacturing a three-dimensional shaped object

Abstract

The present application provides a method for manufacturing a three-dimensional shaped object, which includes: a molding step of obtaining a molded body having a shape corresponding to a shape of a target object and containing an effective amount of a photopolymerization initiator inside, by a vat photopolymerization method using a liquid photocurable composition containing a radical polymerizable monomer, an inorganic filler, a photopolymerization initiator, an activated light absorber, and a polymerization inhibitor; and a post-polymerization step of causing un-polymerized components contained in the molded body to polymerize after irradiating the molded body with activated light having an irradiation intensity of 10 to 10,000 mW / cm 2 at a temperature of 50°C or higher and less than 110°C. In addition, provided is a method for manufacturing a dental restoration by the method for manufacturing a three-dimensional shaped object.

Description

Technical Field

[0001] This invention relates to a method for manufacturing three-dimensional objects. Background Technology

[0002] The technique of creating three-dimensional objects using photocurable resins and curing them by irradiation with light is known as photoforming. Widely known photoforming methods include: liquid bath photopolymerization, which involves irradiating photocurable resin filled in a flat, disc-shaped container with light to create the shape; and material jetting, which involves irradiating the irradiated photocurable resin while simultaneously ejecting it using an inkjet printer. In the manufacture of three-dimensional objects using such photoforming methods, to shorten the modeling time, photoforming is typically performed with short periods of light irradiation, resulting in a molded body with insufficient polymerization and low interlayer strength (also known as the "modeling stage" or "molding process"). This body is then cleaned and finally cured by additional light irradiation and / or heating.

[0003] In dentistry, dental restorations such as dentures and crowns require high-precision manufacturing to create unique shapes that correspond to the specific conditions of each patient's oral cavity. If light modeling is used based on CAD (Computer-Aided Design) data obtained from digital data such as intraoral scans, it is easy to manufacture three-dimensional models that accurately reproduce the designed shape. Because dental restorations used intraorally require such high precision for fitting into each patient's mouth, thorough curing is necessary during final curing. However, due to the deformation caused by polymerization shrinkage during this process, and the resulting stress between the modeling layers during light modeling, cracking can easily occur internally and / or on the surface of the three-dimensional model.

[0004] Therefore, technologies for suppressing these problems have been studied. For example, Patent Document 1 describes a "method for manufacturing dental three-dimensional models, wherein the dental three-dimensional model obtained by modeling using a dental photo-modeling three-dimensional printing material and under recommended conditions of any photo-modeling three-dimensional printing machine does not require final curing based on a light and / or heat-type post-curing device, wherein the dental photo-modeling three-dimensional printing material is a dental photo-modeling three-dimensional printing material, characterized in that it comprises: at least one or more monofunctional acrylate monomers having an aromatic ring (a); and a photopolymerization initiator (b), wherein the electronegativity difference between covalently adjacent atoms constituting the monofunctional acrylate monomer (a) having an aromatic ring is less than 1.00."

[0005] In addition, Patent Document 2 describes a suitable composition for manufacturing artificial teeth and denture bases using a three-dimensional (3D) printing method, which is characterized by comprising a photocurable adhesive mixture, wherein, relative to the total weight of the composition, the photocurable adhesive mixture comprises 0 to 50% by weight of a solution of polymeric poly(methyl methacrylate) dissolved in a methyl methacrylate monomer solvent, 5 to 20% by weight of at least one multifunctional aliphatic (meth)acrylate, 5 to 40% by weight of at least one aliphatic urethane (meth)acrylate oligomer, 25 to 65% by weight of at least one difunctional bisphenol A dimethacrylate, 0.1 to 5% by weight of at least one photoinitiator, 0.05 to 2% by weight of at least one light stabilizer, and 0.1 to 3% by weight of a coloring pigment.

[0006] Furthermore, not specifically limited to the dental field, as a technique for suppressing polymerization shrinkage during final curing, Patent Document 3 describes a "composition for optical stereoscopic modeling, comprising: (A) an aromatic cationic polymerizable compound having two or more aromatic rings and three or more glycidyl ether structures; (B) an aliphatic cationic polymerizable compound having one or more alcoholic hydroxyl groups and two or more glycidyl ether structures and / or a cationic polymerizable compound having an oxetyl group; (C) a free radical polymerizable compound having one or more alcoholic hydroxyl groups and two or more methacryloyl groups and / or acryloyl groups; (D) a sulfonium compound or a bis(alkyl) compound." (A) A cationic polymerization initiator of phenyl iodonium compounds; (E) a free radical polymerization initiator; and (F) a sensitizer, wherein the initiator comprises 10-50% by mass of the aromatic cationic polymerizable compound of (A) above, 1-30% by mass of the aliphatic cationic polymerizable compound of (B) above and / or a cationic polymerizable compound having an oxetyl group, 10-40% by mass of the free radical polymerizable compound of (C) above, 0.1-20% by mass of the cationic polymerization initiator of (D) above, 0.1-20% by mass of the free radical polymerization initiator of (E) above, and 0.05-5% by mass of the sensitizer of (F) above.

[0007] Existing technical documents

[0008] Patent documents

[0009] Patent Document 1: Japanese Patent Application Publication No. 2020-158417

[0010] Patent Document 2: Japanese Patent Application Publication No. 2016-525150

[0011] Patent Document 3: Japanese Patent Application Publication No. 2018-76455 Summary of the Invention

[0012] The problem that the invention aims to solve

[0013] According to the technology described in Patent Document 1, it is believed that by achieving a high degree of polymerization during the modeling stage (molding process) of manufacturing dental three-dimensional objects such as dental repairs using a 3D printer, dental three-dimensional objects with excellent dimensional accuracy can be obtained. However, the photolithography method actually used in Patent Document 1 is a material jetting method using inkjet printing. The dental photolithography three-dimensional printing material used does not contain inorganic filler materials, or even if it does, its content is extremely small. Therefore, when using this technology to manufacture dental repairs, it is difficult to achieve high mechanical strength that will not cause breakage or cracking even under biting pressure during use.

[0014] Furthermore, in the composition described in Patent Document 2, by incorporating polymeric poly(methyl methacrylate), specifically polymethyl methacrylate with a molecular weight of 10,000 or higher, shrinkage during photoforming is reduced, and cracking of the internal and surface of the three-dimensional model is suppressed. However, when such a polymer component is incorporated into the composition, there is a tendency for a decrease in the strength of the three-dimensional model. In addition, since the viscosity of the composition tends to increase, when inorganic fillers are incorporated to achieve high strength, the viscosity increases significantly, making it difficult to handle.

[0015] Furthermore, in the optical stereolithography composition described in Patent Document 3, polymerization shrinkage is reduced by using both free radical polymerizable monomers and cationic polymerizable monomers. However, the cationic polymerization system is easily affected by moisture, making molding difficult due to the storage environment of the composition and the environment during molding. In addition, when inorganic fillers are added to achieve high strength, molding becomes difficult due to the interaction with the inorganic fillers.

[0016] Therefore, the objective of this invention is to provide a method for manufacturing three-dimensional objects, wherein the three-dimensional objects are formed from a cured body of a photocurable resin composition containing a large amount of inorganic fillers for high strength, and the method can suppress deformation associated with polymerization shrinkage and the resulting internal cracking of the objects, thereby enabling the manufacture of three-dimensional objects with high precision and high strength.

[0017] Methods for solving problems

[0018] The specific means for solving the above-mentioned problems include the following implementation methods.

[0019] <1> Methods for manufacturing three-dimensional objects include:

[0020] In the molding process, the height direction of the three-dimensional object is digitized and serialized based on three-dimensional shape data representing the shape of the three-dimensional object, and two-dimensional shape data representing the cross-sectional shape of the three-dimensional object at each serialized height is generated. Using a liquid bath photopolymerization method, the liquid photocurable resin composition is selectively cured at a predetermined location by irradiating it with activation light (ultraviolet or visible light) held in a tank. Based on the two-dimensional shape data, molding layers with shapes corresponding to the two-dimensional shapes at each height are sequentially formed and stacked according to the serialized sequence, thereby obtaining a molded body formed from the cured liquid photocurable resin composition with a shape corresponding to the shape of the three-dimensional object; and

[0021] The post-polymerization process polymerizes the unpolymerized components contained in the molded article.

[0022] The above-mentioned liquid photocurable resin composition comprises:

[0023] (a) Free radical polymerizable monomer: 100 parts by weight

[0024] (b) Inorganic fillers: 5.0–400 parts by weight

[0025] (c) A photopolymerization initiator that absorbs the above-mentioned activation light to generate free radicals: 0.05–10.0 parts by weight

[0026] (d) An activated light absorber that absorbs the above-mentioned activated light: 0.01–2.7 parts by weight, and

[0027] (e) Polymerization inhibitor: 0.01–5.0 parts by weight,

[0028] In the above molding process, a molded article containing an effective amount of the above photopolymerization initiator is obtained.

[0029] Irradiate the above-mentioned molded body at 10–10,000 mW / cm 2 After the activation light of the above intensity is applied, the molded body irradiated with the activation light is heated at a temperature of 50°C or higher and less than 110°C to carry out the above post-polymerization process.

[0030] <2> like <1> The method for manufacturing the three-dimensional model, wherein the above-mentioned liquid bath photopolymerization method includes:

[0031] In the first step, based on the two-dimensional shape data at the height of the initial serialization sequence, the activation light is irradiated onto a predetermined position of the liquid photocurable resin composition held in the above-mentioned tank to cure it, thereby forming a molding layer having a shape corresponding to the above-mentioned two-dimensional shape data, and the molding layer is used as the bonding layer.

[0032] In the second step, the bonding layer is moved upward or downward, and the liquid photocurable resin composition is supplied to the bonding layer directly above or directly below it in the tank.

[0033] In the third step, based on the two-dimensional shape data at the height of the next sequence in the previous step's serialization sequence, the activation light is irradiated onto a predetermined position of the liquid photocurable resin composition supplied directly above or below the aforementioned bonded layer to cure it, thereby forming a new shaping layer having a shape corresponding to the aforementioned two-dimensional shape data. This new shaping layer is then bonded to the aforementioned bonded layer to obtain a laminate having the new shaping layer as the new bonded layer; and

[0034] In the fourth step, the laminate is moved upward or downward to supply the liquid photocurable resin composition directly above or below the new bonded layer in the tank.

[0035] The new layer to be joined is used as the layer to be joined in the third step. The cycle consisting of the third step and the fourth step is repeated. In the final third step, a new modeling layer is formed based on the two-dimensional shape data at the height of the final serialization order, resulting in a stacked body.

[0036] <3> like <1> or <2> The method for manufacturing a three-dimensional object includes a cleaning step of cleaning the molded body after the molding step and before the post-polymerization step.

[0037] <4> like <1> ~ <3> The method for manufacturing a three-dimensional model according to any one of the above-mentioned methods, wherein, by using a liquid photocurable resin composition in which the amount of the activated light absorber (d) is 20 to 90% by mass relative to the amount of the photopolymerization initiator (c) and the amount of the polymerization inhibitor (e) is 5 to 150% by mass relative to the amount of the photopolymerization initiator (c), the above-mentioned molded body containing an effective amount of the photopolymerization initiator (c) is obtained in the above-mentioned molding process.

[0038] <5> Methods for manufacturing dental restorations, wherein, utilizing <1> ~ <4> The method for manufacturing a three-dimensional model as described in any one of the above statements is used to manufacture dental restorations.

[0039] Invention Effects

[0040] According to the manufacturing method of the present invention, it is possible to manufacture three-dimensional objects with excellent mechanical strength, good shape accuracy, and no internal cracks. Detailed Implementation

[0041] The inventors of this application believed that if liquid bath photopolymerization is used as the photomodeling method, and the amount of polymerization shrinkage in the post-polymerization process is considered when designing CAD data, it is possible to obtain a three-dimensional model of the desired shape using a photocurable resin composition containing a large amount of inorganic filler, and conducted research on this. However, when using free radical polymerizable monomers such as (meth)acrylate monomers, which are commonly used as raw materials for dental restorations, as polymerizable monomers, it is impossible to avoid cracking caused by rapid polymerization shrinkage in the post-polymerization process. Therefore, methods to suppress the occurrence of rapid polymerization shrinkage in the post-polymerization process were thoroughly studied. As a result, it was found that by adding a specific amount of activating light absorber and polymerization inhibitor to a photocurable resin composition containing free radical polymerizable monomers, inorganic fillers, and a photopolymerization initiator (which functions through irradiation by activating light), and by leaving an effective amount of the photopolymerization initiator in the molding process without exhausting it, cracking can be prevented by using specific conditions in the post-polymerization process, thus completing the present invention.

[0042] That is, in the manufacturing method of the three-dimensional model involved in this embodiment, it is important to satisfy the following conditions 1 to 3.

[0043] [Condition 1] The liquid photocurable resin composition comprises (a) 100 parts by weight of a free radical polymerizable monomer, (b) 5.0 to 400 parts by weight of an inorganic filler, (c) 0.05 to 10.0 parts by weight of a photopolymerization initiator that absorbs activation light to generate free radicals, (d) 0.01 to 2.7 parts by weight of an activation light absorber that absorbs activation light, and (e) 0.01 to 5.0 parts by weight of a polymerization inhibitor.

[0044] [Condition 2] In the molding process, a molded body containing an effective amount of photopolymerization initiator is obtained.

[0045] [Condition 3] Irradiate the molded body at 10–10,000 mW / cm 2 After being irradiated with activation light of a certain intensity, the molded body irradiated with the activation light is heated at a temperature of 50°C or higher and less than 110°C to carry out the post-polymerization process.

[0046] While the reason why satisfying these conditions can suppress the generation of cracks in the post-polymerization process is unclear, the inventors of this application speculate as follows: It is believed that in the molding process, at the joints of continuous molding layers, or at the boundaries of the irradiated area when the irradiation position is changed sequentially while irradiating with activation light, there exist portions with low polymerization rates (low polymerization rate portions). These low polymerization rate portions are destroyed by shrinkage during the post-polymerization process, resulting in cracking. Therefore, if the polymerization activity in the molding process is increased, the strength of the low polymerization rate portions is increased, and the generation of cracks can be suppressed. On the other hand, if the polymerization activity in the molding process is too high, an effective amount of photopolymerization initiator will not remain in the molded body, and the polymerization rate cannot be sufficiently increased in the post-polymerization process, thus the mechanical strength of the resulting three-dimensional model becomes insufficient. To address this, it is speculated that by setting a manufacturing method that satisfies conditions 1 to 3 above, it is possible to obtain a three-dimensional model that is substantially free of cracks and has high mechanical strength.

[0047] As described above, the method for manufacturing three-dimensional objects according to this embodiment is characterized by satisfying conditions 1 to 3 in the liquid bath photopolymerization method. Therefore, the liquid bath photopolymerization method and conditions 1 to 3 will be described in detail below. It should be noted that in this specification, unless otherwise specified, expressions such as "x to y" using numerical values ​​x and y mean "x or more and y or less". When only the numerical value y is assigned a unit in this expression, that unit also applies to the numerical value x. In addition, in this specification, the term "(meth)acrylate" refers to both "acrylate" and "methacrylate". Similarly, the term "(meth)acryloyl" refers to both "acryloyl" and "methacryloyl".

[0048] <About liquid bath photopolymerization, molding process, and post-polymerization process>

[0049] As described above, in the method for manufacturing a three-dimensional object according to this embodiment, a so-called "liquid bath photopolymerization method" is employed. Here, the liquid bath photopolymerization method refers to the method of digitizing and serializing the height direction of a three-dimensional object based on three-dimensional shape data representing the shape of the three-dimensional object, generating two-dimensional shape data representing the cross-sectional shape of the three-dimensional object at each serialized height, and irradiating a predetermined position of a liquid photocurable resin composition held in a tank with activation light, which is ultraviolet or visible light, thereby selectively curing the liquid photocurable resin composition present at that position.

[0050] In liquid bath photopolymerization, by scanning the outer front of an article with a target three-dimensional shape or the inner surface of a mold of the article using a 3D scanner or a 3D digitizer, three-dimensional shape data of the specified molded body shape can be easily obtained in the form of digital data. Alternatively, three-dimensional shape digital data created using CAD or similar methods can also be used. For example, in the case of manufacturing dental restorations for specific patients, three-dimensional shape (digital) data obtained by 3D scanning with an intraoral scanner can be appropriately used.

[0051] The resulting three-dimensional shape (digital) data, for example through CAD, is discontinuously segmented (digitized) in the height direction of the three-dimensional object at specified fine intervals (height range), typically tens to hundreds of μm, and serialized in the height direction to generate two-dimensional shape data representing the cross-sectional shape of the three-dimensional object at each serialized height.

[0052] Then, using a light-forming device that has a tank for storing the liquid photocurable resin composition and a light source for irradiating activation light, activation light is irradiated onto positions determined based on the two-dimensional shape data of the liquid photocurable resin composition, selectively curing the irradiated portions to obtain a molded body (molding process) formed from the cured liquid photocurable resin composition. That is, based on the two-dimensional shape data, modeling layers with shapes corresponding to the two-dimensional shapes at each height are sequentially formed and stacked in a serialized order, thereby obtaining a molded body formed from the cured liquid photocurable resin composition with a shape corresponding to the shape of a three-dimensional object.

[0053] The molding process will be described in more detail. First, based on the two-dimensional shape data at the height of the initial sequence, activation light is irradiated onto a predetermined position of the liquid photocurable resin composition held in the tank to cure it, thereby forming a molding layer having a shape corresponding to the aforementioned two-dimensional shape data. This molding layer serves as the bonded layer (Step 1). Next, the bonded layer is moved upward or downward, and the liquid photocurable resin composition is supplied to the area directly above or below the bonded layer in the tank (Step 2). Next, based on the two-dimensional shape data at the height of the next sequence in the previous step, activation light is irradiated onto a predetermined position of the liquid photocurable resin composition supplied directly above or below the bonded layer to cure it, thereby forming a new molding layer having a shape corresponding to the aforementioned two-dimensional shape data. This new molding layer is then bonded to the bonded layer to obtain a laminate having this new molding layer as the new bonded layer (Step 3). Then, the laminate is moved up or down, and the liquid photocurable resin composition is supplied to the top or bottom of the new bonded layer in the tank (step 4). The new bonded layer is used as the bonded layer in step 3. The cycle consisting of step 3 and step 4 is repeated. In the final step 3, a new shaping layer is formed based on the two-dimensional shape data at the height of the final serialization sequence to obtain the laminate. The obtained laminate becomes the molded body.

[0054] Depending on the light irradiation method, known liquid bath photopolymerization methods include StereoLithography (SLA), Digital Light Processing (DLP), and Liquid Column Display (LCD). In the method for manufacturing three-dimensional models according to this embodiment, these methods can be used without particular limitation. The light modeling apparatus is also only required for liquid bath photopolymerization; there are no particular limitations, and any apparatus can be used depending on the method employed. It should be noted that the activation light for irradiation can be monochromatic light with a specific single wavelength peak or light with a narrow wavelength distribution, and these peak wavelengths can be irradiated multiple times. Especially from the viewpoint of obtaining more refined and higher-intensity three-dimensional models, an SLA-based light modeling apparatus is preferred.

[0055] The resulting molded body is then cleaned as needed, and the unpolymerized components contained in the molded body are polymerized by additional light irradiation and / or heating (post-polymerization process).

[0056] <Regarding Condition 1>

[0057] In the method for manufacturing a three-dimensional object according to this embodiment, the liquid photocurable resin composition used in the molding process needs to include the following liquid photocurable resin composition:

[0058] (a) Free radical polymerizable monomer: 100 parts by weight;

[0059] (b) Inorganic fillers: 5.0–400 parts by weight;

[0060] (c) Photopolymerization initiator that absorbs and activates light to generate free radicals: 0.05–10.0 parts by weight;

[0061] (d) Activated light absorber for absorbing activated light: 0.01–2.7 parts by weight; and

[0062] (e) Polymerization inhibitor: 0.01 to 5.0 parts by weight.

[0063] It should be noted that, in order to achieve high-precision molding of the molded body and prevent air bubbles from being incorporated into the interior, the liquid photocurable resin composition preferably has a low viscosity. On the other hand, there is a tendency for the strength of the cured body to decrease if the viscosity of the resin composition before curing is too low. For this reason, the viscosity of the liquid photocurable resin composition at 25°C is preferably 5 to 50,000 mPa·s, particularly 10 to 30,000 mPa·s.

[0064] The following describes the composition and dosage of the liquid photocurable resin composition.

[0065] [(a) Free radical polymerizable monomers]

[0066] As a (a) free radical polymerizable monomer, monomers with free radical polymerizable properties can be used without particular restrictions. However, (meth)acrylate monomers are preferred because of their fast curing speed and the excellent strength of the resulting three-dimensional model.

[0067] As (meth)acrylate monomers, any of monofunctional (meth)acrylates, difunctional (meth)acrylates, and polyfunctional (meth)acrylates with three or more functions can be used. To manufacture three-dimensional models with higher strength, based on the total mass of all free radical polymerizable monomers, it is preferable that 50% by mass or more, particularly 80% by mass, be polyfunctional (meth)acrylates with two or more functions. The proportion of polyfunctional (meth)acrylates with two or more functions is more preferably 95% by mass.

[0068] Preferred polyfunctional (meth)acrylates with two or more functions include, for example, (meth)acrylates containing a bisphenol A backbone such as 2,2'-bis{4-[3-(meth)acryloyloxy-2-hydroxypropoxy]phenyl}propane, 2,2'-bis[4-(meth)acryloyloxyphenyl]propane, and 2,2'-bis[4-(meth)acryloyloxypolyethoxyphenyl]propane; and ethylene glycol-based (meth)acrylates such as triethylene glycol dimethacrylate and ethylene glycol dimethacrylate. Acrylates; aliphatic di(meth)acrylates such as 1,3-propanediol di(meth)acrylate and 1,9-nonanediol dimethacrylate; (meth)acrylates containing urethane groups such as 1,6-bis(methacryloyloxy-2-ethoxycarbonylamino)-2,2,4-trimethylhexane; trifunctional (meth)acrylates such as trimethylolpropane trimethacrylate; (meth)acrylates containing an isocyanate backbone such as tri(2-methacryloyloxyethyl)isocyanurate; and so on. Among these, 2,2'-bis[4-(meth)acryloyloxyphenyl]propane, 2,2'-bis[4-(meth)acryloyloxypolyethoxyphenyl]propane, triethylene glycol dimethacrylate, and tri(2-methacryloyloxyethyl)isocyanurate are preferred due to their low viscosity and excellent strength of the resulting three-dimensional shapes.

[0069] In addition, examples of monofunctional (meth)acrylates suitable for use with polyfunctional (meth)acrylates with two or more functions include methyl (meth)acrylate, ethyl (meth)acrylate, isopropyl (meth)acrylate, hydroxyethyl (meth)acrylate, tetrahydrofurfuryl (meth)acrylate, and glycidyl (meth)acrylate.

[0070] It should be noted that these free radical polymerizable monomers can be used alone or in combination with two or more.

[0071] [(b) Inorganic packing]

[0072] In the case of liquid photocurable resin compositions, in order to improve the rigidity and other mechanical strength of the obtained three-dimensional models, it is necessary to contain 5 to 400 parts by mass of (b) inorganic filler relative to 100 parts by mass of (a) free radical polymerizable monomer. If the content of (b) inorganic filler is too high, the viscosity of the liquid photocurable resin composition becomes too high. On the other hand, if the content of (b) inorganic filler is too low, the mechanical strength of the obtained three-dimensional models becomes insufficient. Therefore, the content of (b) inorganic filler is preferably 10 to 300 parts by mass relative to 100 parts by mass of (a) free radical polymerizable monomer, more preferably 20 to 200 parts by mass.

[0073] (b) There are no particular restrictions on the material of the inorganic filler; for example, any material used as a filling material in dental restorative materials can be used. Specifically, examples include: elemental metals; metal oxides or metal composite oxides; metal salts such as fluorides, carbonates, sulfates, silicates, hydroxides, chlorides, sulfites, and phosphates; complexes of these metal salts; and so on. Preferred materials include metal oxides such as amorphous silica, quartz, alumina, titanium dioxide, zirconium oxide, barium oxide, yttrium oxide, lanthanum oxide, and ytterbium oxide; silica-based composite oxides such as silica-zirconium oxide, silica-titanium oxide, silica-titanium oxide-barium oxide, and silica-titanium oxide-zirconium oxide; glasses such as borosilicate glass, aluminosilicate glass, and fluoroaluminosilicate glass; metal fluorides such as barium fluoride, strontium fluoride, yttrium fluoride, lanthanum fluoride, and ytterbium fluoride; inorganic carbonates such as calcium carbonate, magnesium carbonate, strontium carbonate, and barium carbonate; metal sulfates such as magnesium sulfate and barium sulfate; and so on. In the manufacture of dental restorations, silica-zirconia, silica-titanium oxide, silica-titanium oxide-barium oxide, and silica-titanium oxide-zirconia particles are preferred due to their strong X-ray imaging properties. From the viewpoint of the wear resistance of the cured body, silica-zirconia particles are the most preferred.

[0074] (b) There is no particular limitation on the average particle size of the inorganic filler. Fillers with an average particle size of 0.01 to 100 μm (preferably 0.01 to 10 μm), which are commonly used as dental restorative materials, can be used appropriately depending on the purpose. Furthermore, various combinations of these fillers can be used, as well as combinations of fillers with different average particle sizes. In addition, (b) inorganic fillers can also be used as so-called organic-inorganic composite fillers.

[0075] It should be noted that, considering the improvement of compatibility with polymerizable monomers, the enhancement of mechanical strength, and water resistance, it is preferable to treat (b) the inorganic filler with a surface treatment agent, such as a silane coupling agent. The surface treatment can be performed using any known method. As a silane coupling agent, preferred options include methyltrimethoxysilane, methyltriethoxysilane, methyltrichlorosilane, dimethyldichlorosilane, trimethylchlorosilane, vinyltrichlorosilane, vinyltriethoxysilane, vinyltri(β-methoxyethoxy)silane, γ-methacryloyloxypropyltrimethoxysilane, methacryloyloxyoctyl-8-trimethoxysilane, γ-chloropropyltrimethoxysilane, γ-glycidoxypropylmethoxysilane, and hexamethyldisilazane.

[0076] [(c) Photopolymerization initiator that absorbs the activating light irradiated during the molding process]

[0077] (c) The photopolymerization initiator has the function of generating free radicals by means of activation light, specifically ultraviolet or visible light, irradiated by a light source mounted on a light modeling device, thereby enabling (a) free radical polymerizable monomers to undergo free radical polymerization. Therefore, (c) the photopolymerization initiator needs to absorb the light (wavelength) used (hereinafter also referred to as the "polymerization initiation wavelength") and generate free radicals.

[0078] (c) If the content of photopolymerization initiator is too high, burrs and other defects will appear in the resulting three-dimensional model, resulting in poor modeling accuracy. On the other hand, if the content of (c) photopolymerization initiator is too low, modeling will not be possible during the molding process. Therefore, the content of (c) photopolymerization initiator needs to be 0.05 to 10.0 parts by mass relative to 100 parts by mass of (a) free radical polymerizable monomer. In order to more effectively retain an effective amount of photopolymerization initiator in the molded body, the content of (c) polymerization initiator is preferably 0.3 to 5.0 parts by mass relative to 100 parts by mass of (a) free radical polymerizable monomer, and more preferably 0.5 to 3.0 parts by mass.

[0079] It should be noted that when the activation light irradiated in the post-polymerization process is of a different wavelength than the activation light irradiated in the molding process, the liquid photocurable resin composition preferably contains, in addition to (c) a photopolymerization initiator that absorbs the activation light irradiated in the molding process, a photopolymerization initiator that absorbs the activation light irradiated in the post-polymerization process. In this case, relative to 100 parts by weight of the free radical polymerizable monomer (a), the content of the photopolymerization initiator (c') is preferably 0.05 to 5.0 parts by weight, more preferably 0.1 to 3.0 parts by weight, and even more preferably 0.3 to 1.0 parts by weight.

[0080] As a photopolymerization initiator, a substance that satisfies the above conditions can be appropriately selected from known photopolymerization initiators. There are no particular limitations on the photopolymerization initiator that can be selected; for example, cleavage-type photopolymerization initiators, 2-molecule hydrogen-abstraction type photopolymerization initiators, photoacid-producing agents, and combinations thereof can be mentioned. Furthermore, these photopolymerization initiators can be used in combination with photosensitive pigments, electron-donating compounds, etc.

[0081] Examples of preferred pyrolysis-type photopolymerization initiators include, for example, acylphosphine oxide compounds such as diphenyl(2,4,6-trimethylbenzoyl)phosphine oxide and phenylbis(2,4,6-trimethylbenzoyl)phosphine oxide; benzo[a]ketal compounds, benzoyne compounds, α-aminoacetophenone compounds, α-hydroxyacetophenone compounds, titanoceramethylene compounds, acyl oxime compounds; and so on. Examples of photoacid generators include, for example, iodonium salt compounds such as p-isopropylphenyl-p-methylphenyliodonium tetra(pentafluorophenyl)borate; sulfonium salt compounds such as dimethylbenzoylmethylsulfonium hexafluoroantimonate; halomethyl-substituted triazine compounds such as 2,4,6-tris(trichloromethyl)-s-triazine; and so on. Examples of photosensitive pigments include ketone compounds, coumarin pigments, anthocyanin pigments, thiazide pigments, acridine pigments, xanthones, squaric acid pigments, pyranonium salt pigments, fused polycyclic aromatic compounds (anthracene, perylene, etc.), and thioxanone compounds. Examples of electron-donating compounds include 4-dimethylaminobenzoate, 4-dimethylaminotoluene, p-dimethoxybenzene, 1,2,4-trimethoxybenzene, and thiophene compounds.

[0082] Considering that the wavelength of the activation light irradiated from the light source mounted on a conventional light modeling device is 350 to 420 nm, assuming that the molding process is carried out using a light modeling device with such a light source and the activation light with a wavelength of 450 to 490 nm is irradiated in the post-polymerization process, it is preferable to use phenyl bis(2,4,6-trimethylbenzoyl)phosphine oxide as (c) photopolymerization initiator and camphorquinone and amine as (c') photopolymerization initiator.

[0083] [(d) Activation light absorber for activating light irradiated during the molding process]

[0084] To prevent excessive transmission of activation light from the photoforming device, which could reduce the shaping accuracy of the molded body, the liquid photocurable resin composition needs to contain an activation light absorber (d) that absorbs the activation light from the photoforming device.

[0085] (d) If the content of the activated light absorber is too high, the activated light generated from the light source of the light modeling device in the molding process cannot pass through the liquid photocurable resin composition, making it impossible to manufacture a three-dimensional model. On the other hand, if the content of (d) the activated light absorber is too low, the modeling accuracy of the obtained three-dimensional model will decrease. Therefore, the content of (d) the activated light absorber needs to be 0.01 to 2.7 parts by mass relative to 100 parts by mass of (a) the free radical polymerizable monomer. The content of (d) the activated light absorber is preferably 0.04 to 3.0 parts by mass relative to 100 parts by mass of (a) the free radical polymerizable monomer, more preferably 0.08 to 2.0 parts by mass, and even more preferably 0.25 to 1.0 parts by mass.

[0086] Since both (d) the activating light absorber and (c) the photopolymerization initiator absorb the activation light irradiated from the photoforming device, the greater the amount of (d) the activating light absorber, the less free radicals are generated from (c) the photopolymerization initiator, and the greater the amount of (c) the photopolymerization initiator remaining in the molded body after photoforming. As described above, in the method for manufacturing three-dimensional objects according to this embodiment, free radicals are generated from the remaining (c) photopolymerization initiator by additional light irradiation after photoforming, and these free radicals contribute to increasing the polymerization rate during the additional heat treatment. Therefore, in the method for manufacturing three-dimensional objects according to this embodiment, the relationship between the amount of (c) the photopolymerization initiator and the amount of (d) the activating light absorber is very important in improving the mechanical strength of the final three-dimensional object.

[0087] The inventors of this application conducted in-depth research and found that, in order to leave residual photopolymerization initiator after photoforming in the molding process and generate a sufficient amount of free radicals when additional light irradiation is applied in the subsequent polymerization process, the content of (d) activated light absorber is preferably 20 to 90% by mass, more preferably 30 to 80% by mass, and even more preferably 40 to 70% by mass, relative to the content of (c) photopolymerization initiator.

[0088] As (d) activated light absorber, any compound that absorbs activated light irradiated by a light source mounted on a light modeling device is acceptable, without particular limitation. Examples include triazole compounds such as 2-(hydroxy-5-methylphenyl)-2H-benzotriazole and 2-(3-tert-butyl-2-hydroxy-5-methylphenyl)-5-chloro-2H-benzotriazole; benzophenone compounds such as 2,4-dihydroxybenzophenone and 2-hydroxy-4-methoxybenzophenone; and so on.

[0089] [(e) Polymerization inhibitors]

[0090] In the case of liquid photocurable resin compositions, in order to improve the storage stability of the liquid photocurable resin composition and prevent unnecessary partial curing caused by the diffusion of free radicals generated by activation light during the molding process to the required extent, it is necessary to include (e) a polymerization inhibitor.

[0091] If the content of (e) inhibitor is too high, the curing of the liquid photocurable resin composition in the molding process becomes insufficient, resulting in poor shaping. On the other hand, if the amount of (e) inhibitor is too low, the storage stability of the liquid photocurable resin composition decreases, and the shaping accuracy of the molded article decreases. Therefore, the content of (e) inhibitor needs to be 0.01 to 5.0 parts by weight relative to 100 parts by weight of (a) free radical polymerizable monomer. The content of (e) inhibitor is preferably 0.03 to 3.0 parts by weight relative to 100 parts by weight of (a) free radical polymerizable monomer, and more preferably 0.05 to 2.0 parts by weight.

[0092] As described above, in the manufacturing method of the three-dimensional model according to this embodiment, the residual (c) polymerization initiator in the molded body generates free radicals, thereby increasing the polymerization rate in the subsequent polymerization process. Therefore, if the amount of (e) polymerization inhibitor is too large relative to the amount of (c) photopolymerization initiator, the free radicals generated in the molded body react with the polymerization inhibitor during additional light irradiation, and the polymerization rate cannot be sufficiently increased during subsequent additional heating. Conversely, if the amount of (e) polymerization inhibitor is too small relative to the amount of (c) photopolymerization initiator, the consumption of (c) photopolymerization initiator in the molding process increases, and therefore insufficient free radicals are generated during additional light irradiation in the subsequent polymerization process, resulting in insufficient increase in the polymerization rate. Therefore, the content of (e) polymerization inhibitor is preferably 5 to 150% by mass, more preferably 8 to 120% by mass, and even more preferably 12 to 120% by mass, relative to the content of (c) photopolymerization initiator.

[0093] As an inhibitor of polymerization (e), any compound that reacts with free radicals generated in the liquid photocurable resin composition and deactivates the free radicals is acceptable, without particular limitation. Examples include di-tert-butyl-p-cresol and 4-methoxyphenol.

[0094] [Any other ingredients]

[0095] The liquid photocurable resin composition may include other components such as chain transfer agents as needed. Examples of chain transfer agents include α-methylstyrene dimer. By incorporating chain transfer agents, the generation of deformation and cracks caused by polymerization shrinkage tends to be suppressed. On the other hand, if the content of chain transfer agent is too high, the polymerization rate in the molding process decreases, and it may be impossible to obtain a molded article by light irradiation using a photoforming device. Therefore, the content of chain transfer agent is preferably 1.0 parts by mass or less, more preferably 0.5 parts by mass or less, and even more preferably 0.3 parts by mass or less, relative to 100 parts by mass of (a) free radical polymerizable monomer.

[0096] <Regarding condition 2>

[0097] In the manufacturing method of the three-dimensional model involved in this embodiment, as described above, it is important that there is no unreacted (c) photopolymerization initiator remaining in the molded body immediately after the molding process and that there is no (c) photopolymerization initiator remaining in the three-dimensional model after the post-polymerization process.

[0098] (c) Whether the photopolymerization initiator remains can be confirmed by any method. For example, when using a (c) photopolymerization initiator such as phenyl bis(2,4,6-trimethylbenzoyl)phosphine oxide, which has absorption in the visible light region, the yellow color is confirmed because phenyl bis(2,4,6-trimethylbenzoyl)phosphine oxide remains in the molded body immediately after the molding process, and the color fades after the subsequent polymerization process. Alternatively, the presence of (c) photopolymerization initiator residue can be confirmed by pulverizing a portion of the obtained three-dimensional model, extracting it with any organic solvent, and analyzing it using known analytical methods (e.g., high performance liquid chromatography, gas chromatography, etc.).

[0099] The molded body immediately after the molding process only needs to have a polymerization rate sufficient to maintain the shape of the target three-dimensional object. The polymerization rate of the molded body is preferably 55% or more, more preferably 60% or more, and even more preferably 65% ​​or more. On the other hand, if the polymerization rate of the molded body is too high, the shaping accuracy of the resulting three-dimensional object may decrease. Therefore, the polymerization rate of the molded body is preferably 95% or less, more preferably 90% or less, and even more preferably 85% or less.

[0100] <Regarding condition 3>

[0101] In the method for manufacturing three-dimensional objects according to this embodiment, it is preferable to use an organic solvent to clean the molded body obtained in the molding process. There are no particular limitations on the organic solvent; examples include alcohol-based solvents such as ethanol, methanol, and isopropanol; ketone-based solvents such as acetone and methyl ethyl ketone; ether-based solvents such as diethyl ether, diisopropyl ether, and tetrahydrofuran; amide-based solvents such as N-methylpyrrolidone and dimethylacetamide; halogen-based solvents such as dichloromethane and chloroform; and so on. From the viewpoint of high cleaning efficiency and low environmental impact, alcohol-based solvents are preferred.

[0102] In the manufacturing method of the three-dimensional model involved in this embodiment, as a post-polymerization process, it is necessary to irradiate and heat the molded body.

[0103] Regarding the wavelength of the additional light irradiation in the post-polymerization process, there is no particular limitation as long as it is the wavelength at which the residual (c) photopolymerization initiator in the molded body absorbs light and generates free radicals. As for the irradiation intensity, to ensure that the residual (c) photopolymerization initiator in the molded body generates a sufficient amount of free radicals, 5 mW / cm² is preferred. 2The above, more preferably 10mW / cm 2 The above is further optimized to 30mW / cm 2 That's all. On the other hand, if the intensity of the additional light irradiation is too high, the molded body will be overheated, causing cracks in the three-dimensional model. Therefore, the irradiation intensity is preferably 10,000 mW / cm². 2 The duration of the additional light irradiation is not particularly limited, but is preferably 1 minute or more, more preferably 3 minutes or more, and even more preferably 5 minutes or more.

[0104] Heating the molded body simultaneously with the light irradiation added in the post-polymerization process is also suitable. This heating promotes the decomposition of residual (c) photopolymerization initiator in the molded body and increases the efficiency of free radical generation. On the other hand, if the heating temperature is too high, the post-polymerization proceeds violently, and cracking may occur in the three-dimensional molded object. Therefore, the lower limit of the heating temperature when heating simultaneously with light irradiation is preferably 37°C or higher (particularly preferably 39°C or higher), and the upper limit is preferably 50°C or lower (particularly preferably 45°C or lower).

[0105] In the post-polymerization process, after additional light irradiation of the molded body, a final curing based on heat is required. It is believed that during this heating, free radicals generated during the additional light irradiation react, thereby increasing the polymerization rate of the resulting three-dimensional model. Therefore, from the viewpoint of more effectively increasing the polymerization rate, prolonged heating at high temperatures is preferred. On the other hand, if the heating temperature is too high, cracks may occur inside the three-dimensional model due to polymerization shrinkage and deformation accompanying the rapid increase in polymerization rate. Furthermore, a decrease in work efficiency can also occur with prolonged heating. Therefore, controlling the heating temperature in the post-polymerization process is crucial to effectively obtain high-strength three-dimensional models without cracking.

[0106] As for temperature control, it is preferable to perform temperature conditions 1, 2, and 3 as shown below in sequence, with a total heating time preferably of 5 minutes or more.

[0107] Temperature condition 1: Above 50℃ and below 75℃

[0108] Temperature condition 2: Above 75℃ and below 90℃

[0109] Temperature condition 3: Above 90℃ and below 110℃

[0110] Temperature condition 1 is preferably 55°C or higher and less than 70°C. Temperature condition 2 is preferably 75°C or higher and less than 85°C. Temperature condition 3 is preferably 90°C or higher and less than 100°C. Furthermore, the heating time in temperature condition 1 is preferably 3 to 120 minutes, more preferably 5 to 60 minutes. The heating time in temperature condition 2 is preferably 3 to 120 minutes, more preferably 5 to 60 minutes. The heating time in temperature condition 3 is preferably 3 to 120 minutes, more preferably 5 to 60 minutes.

[0111] It should be noted that if the combined heating time of temperature conditions 1 and 2 is more than 10 minutes, temperature condition 3 can be omitted. If the heating time of temperature condition 1 is more than 15 minutes, temperature conditions 2 and 3 can be omitted.

[0112] In the manufacturing method of the three-dimensional model according to this embodiment, the polymerization rate of the three-dimensional model is increased by subjecting the molded body to additional light irradiation and additional heating, thereby increasing the mechanical strength of the obtained three-dimensional model. Therefore, a high polymerization rate of the three-dimensional model is preferable. The polymerization rate of the three-dimensional model is preferably 80% or more, more preferably 85% or more, and even more preferably 88% or more.

[0113] <On the Manufacturing Methods of Dental Restorative Materials>

[0114] The resulting three-dimensional model exhibits high polymerization rate and is virtually free of internal and surface cracks, resulting in high mechanical strength. Therefore, the obtained three-dimensional model can be used for various applications and is also suitable for dental restorative materials. Examples of preferred dental restorative materials include denture materials and crown restoration materials. From the viewpoint of suppressing crack formation, smaller sizes of the three-dimensional model are more advantageous, making it particularly preferred for use as a crown restoration material.

[0115] Example

[0116] The present invention will be described in more detail below through embodiments, but the present invention is not limited to these embodiments.

[0117] The following shows the compounds used in the examples and comparative examples, and their abbreviations.

[0118] (a) Photopolymerizable monomers

[0119] D-2.6E: Bisphenol A ethylene glycol (EO) adduct dimethacrylate (EO adduct number: average 2.6)

[0120] UDMA: Carbamate dimethacrylate

[0121] 3G: Triethylene glycol dimethacrylate

[0122] (b) Inorganic fillers

[0123] F-1: γ-methacryloyloxypropyltrimethoxysilane-treated spherical silica-zirconia particles (average particle size: 0.5 μm)

[0124] γ-methacryloxypropyltrimethoxysilane-treated spherical silica-zirconia particles (average particle size: 0.08 μm)

[0125] (c) Photopolymerization initiator

[0126] BAPO: Diacylphosphine oxide

[0127] (d) Activated light absorber

[0128] SS3: 2-(3-tert-butyl-2-hydroxy-5-methylphenyl)-5-chloro-2H-benzotriazole

[0129] (e) Polymerization inhibitors

[0130] BHT: Butylated hydroxytoluene

[0131] HQME: Hydroquinone methyl ether

[0132] <Example 1>

[0133] A liquid photocurable resin composition was prepared by adding each of the components shown in Table 1 in the amounts shown in Table 1 relative to 100 parts by mass of polymerizable monomer (mixing mass ratio: D-2.6E / UDMA / 3G=30 / 50 / 20), stirring under red light until homogeneous, and then degassing.

[0134] [Table 1]

[0135]

[0136] ※ {(d) parts by weight / (c) parts by weight} × 100 (%) or {(e) parts by weight / (c) parts by weight} × 100 (%)

[0137] Next, using the obtained liquid photocurable resin composition, a molded body of a specified shape (formed from the cured liquid photocurable resin composition) was obtained using a 3D printer (DWS Corporation: DW029D). After cleaning, it was then subjected to post-polymerization under the conditions shown in Table 2 to produce bending test pieces (cured bodies of rectangular blocks measuring 2.05mm × 2.05mm × 25.05mm) and test pieces for polymerization rate determination and crack evaluation. A circular cured body with a thickness of 1.0 mm.

[0138] The obtained test pieces were used to perform flexural strength testing, polymerization rate testing, and crack evaluation as shown below. The evaluation results are shown in Table 3.

[0139] (1) Bending strength test

[0140] The cured body, which was made into a bending test piece, was trimmed into a prism shape of 2mm×2mm×25mm using #800 water-resistant abrasive paper. The test piece was installed on a testing machine (Autograph AG5000D, manufactured by Shimadzu Corporation) and the 3-point bending failure strength was measured under the conditions of a 20mm distance between the support points and a crosshead speed of 1mm / min.

[0141] (2) Polymerization rate determination

[0142] For the cured body used to make test pieces for polymerization rate determination and crack evaluation, the polymerization rate is calculated by measuring near-infrared spectroscopy using the transmission method, as shown below.

[0143] Near-infrared spectroscopy (NIR) measurements were performed on both the pre-porimation paste (BP) and the final molded product (MP). From the obtained spectra, the wavenumber at 6165 cm⁻¹, which corresponds to the double bond, was determined. -1 The peak areas of the absorption peaks of =CH appearing nearby are S(HSP2)BP and S(HSP2)MP. Additionally, the wavenumber 4920 cm⁻¹ attributable to the -NH⁻ group in the urethane bond present in the polymerizable monomer is calculated. -1 The peak areas of the absorption peaks appearing nearby are: S(NH)BP and S(NH)MP. Then, the polymerization rate R (%) is calculated according to the following formula.

[0144] R(%)=100-100×{S(HSP2 / NH)MP} / {S(HSP2 / NH)BP}

[0145] S(HSP2 / NH)BP={S(HSP2)BP} / {S(NH)BP}

[0146] S(HSP2 / NH)MP={S(HSP2)MP} / {S(NH)MP}

[0147] It should be noted that, for NIR measurements, the Perkin Elmer Spectrum One was used as the measuring device, with a cumulative count of 4 times and a resolution of 4 cm. -1 It is carried out under the following conditions.

[0148] In addition, similar to the test pieces used for polymerization rate determination and crack evaluation, the polymerization rate was also determined on the molded body after rigid molding.

[0149] (3) Evaluation of cracks

[0150] The cured body, used as a test piece for polymerization rate determination and crack evaluation, was observed under a microscope to evaluate the presence of cracks on its surface. Additionally, the cured body was ground to a depth of 100–500 μm, and its surface was observed under a microscope every 100 μm to evaluate the presence of internal cracks. The evaluation criteria for crack evaluation are as follows.

[0151] -Evaluation Criteria-

[0152] A: There are no cracks on the surface or inside of the cured body.

[0153] B: Cracks were observed only on the surface of the cured body.

[0154] C: Cracks exist on the surface and inside of the cured body.

[0155] <Examples 2-11 and Comparative Examples 1-2>

[0156] Except for changing the post-polymerization process conditions to those shown in Table 2, test pieces were prepared and evaluated in the same manner as in Example 1. The results are shown in Table 3.

[0157] [Table 2]

[0158]

[0159] [Table 3]

[0160]

[0161] As shown in Table 3, for Examples 1 to 11, which were subjected to heat treatment after light irradiation in the post-polymerization process, the polymerized bodies and three-dimensional models had high polymerization rates, excellent mechanical strength, and no cracks were observed inside the three-dimensional models.

[0162] In contrast, for Comparative Example 1, which only underwent heat treatment in the post-polymerization process, and Comparative Example 2, which only underwent light irradiation in the post-polymerization process, the polymerization rate of the three-dimensional model was lower than that of Examples 1-11, resulting in poor mechanical strength. Furthermore, in Comparative Example 1, cracks were present inside and on the surface of the three-dimensional model.

[0163] <Examples 12-22 and Comparative Examples 3-6>

[0164] Except for changes to the composition shown in Table 4, a liquid photocurable resin composition was prepared in the same manner as in Example 1. Then, using the obtained liquid photocurable resin composition, test pieces were prepared and evaluated in the same manner as in Example 1. The results are shown in Table 5.

[0165] [Table 4]

[0166]

[0167] [Table 5]

[0168]

[0169] As shown in Table 5, in Examples 12-22, with appropriate adjustments to the addition amounts of activating light absorber (SS3) and polymerization inhibitors (HQME, BHT), the moldings and three-dimensional shapes exhibited high polymerization rates, excellent mechanical strength, and no cracks were observed inside or on the surface of the three-dimensional shapes.

[0170] In contrast, in Comparative Example 3, which had a higher amount of activated light absorber (SS3), and in Comparative Example 5, which had a higher amount of polymerization inhibitors (HQME, BHT), the polymerization rates of the molded articles and three-dimensional shapes were lower than those of Examples 12-22, resulting in poor mechanical strength. Furthermore, in Comparative Example 4, which had a lower amount of activated light absorber (SS3), and in Comparative Example 6, which had a lower amount of polymerization inhibitors (HQME, BHT), although the polymerization rate of the molded articles was high, the polymerization rate of the three-dimensional shapes was lower than that of Examples 12-22, resulting in poor mechanical strength. In addition, in Comparative Example 6, cracks were present both inside and on the surface of the three-dimensional shape.

Claims

1. A method for manufacturing a three-dimensional model, the method comprising: In the molding process, the height direction of the three-dimensional object is digitized and serialized based on three-dimensional shape data representing the shape of the three-dimensional object, and two-dimensional shape data representing the cross-sectional shape of the three-dimensional object at each serialized height is generated. Using a liquid bath photopolymerization method, the liquid photocurable resin composition is selectively cured at a predetermined location by irradiating it with activation light (ultraviolet or visible light) held in a tank. Based on the two-dimensional shape data, molding layers with shapes corresponding to the two-dimensional shapes at each height are sequentially formed and stacked according to the serialized order, thereby obtaining a molded body formed from the cured liquid photocurable resin composition with a shape corresponding to the shape of the three-dimensional object; and The post-polymerization process polymerizes the unpolymerized components contained in the molded body. The liquid photocurable resin composition comprises: (a) Free radical polymerizable monomer: 100 parts by weight (b) Inorganic fillers: 20-200 parts by weight (c) A photopolymerization initiator that absorbs the activation light to generate free radicals: 0.05–10.0 parts by weight (d) An activated light absorber that absorbs the activated light: 0.01 to 2.7 parts by weight, and (e) Polymerization inhibitor: 0.01–5.0 parts by weight, In the molding process, a molded article containing an effective amount of the photopolymerization initiator is obtained. Irradiate the molded body with 10 to 10,000 mW / cm 2 After the activation light is applied to the irradiation intensity, the molded body irradiated with the activation light is heated at a temperature of 50°C or higher and less than 110°C to carry out the post-polymerization process.

2. The method for manufacturing a three-dimensional object as described in claim 1, wherein, The liquid bath photopolymerization method includes: In the first step, based on the two-dimensional shape data at the height of the initial serialization sequence, the activation light is irradiated onto a predetermined position of the liquid photocurable resin composition held in the tank to cure it, thereby forming a molding layer having a shape corresponding to the two-dimensional shape data, and the molding layer is used as the bonding layer. In the second step, the bonded layer is moved up or down, and the liquid photocurable resin composition is supplied to the area directly above or below the bonded layer in the tank. In the third step, based on the two-dimensional shape data at the height of the next sequence in the previous step's serialization sequence, the activation light is irradiated onto a predetermined position of the liquid photocurable resin composition supplied directly above or below the bonded layer to cure it, thereby forming a new shaping layer with a shape corresponding to the two-dimensional shape data. This new shaping layer is then bonded to the bonded layer to obtain a laminate having this new shaping layer as the new bonded layer; and In the fourth step, the laminate is moved upward or downward to supply the liquid photocurable resin composition directly above or below the new bonded layer in the tank. The new layer to be bonded is used as the layer to be bonded in the third step, and the cycle consisting of the third step and the fourth step is repeated. In the final third step, a new modeling layer is formed based on the two-dimensional shape data at the height of the final serialization order, resulting in a stacked body.

3. The method for manufacturing a three-dimensional object as described in claim 1 or 2, wherein, The process includes a cleaning process that cleans the molded body after the molding process and before the post-polymerization process.

4. The method for manufacturing a three-dimensional object as described in claim 1 or 2, wherein, By using a liquid photocurable resin composition in which the amount of the activated light absorber (d) is 20 to 90% by mass relative to the amount of the photopolymerization initiator (c) and the amount of the polymerization inhibitor (e) is 5 to 150% by mass relative to the amount of the photopolymerization initiator (c), the molded article containing an effective amount of the photopolymerization initiator (c) is obtained in the molding process.

5. A method for manufacturing dental restorations, wherein, A dental restoration is manufactured using the manufacturing method of any one of claims 1 to 4 for a three-dimensional model.

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