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WO2025164130A1 - Composition durcissable pour stéréolithographie tridimensionnelle, son procédé de production, procédé de production d'un produit stéréolithographique tridimensionnel et procédé de production d'un article de restauration dentaire - Google Patents

Composition durcissable pour stéréolithographie tridimensionnelle, son procédé de production, procédé de production d'un produit stéréolithographique tridimensionnel et procédé de production d'un article de restauration dentaire

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Publication number
WO2025164130A1
WO2025164130A1 PCT/JP2024/044729 JP2024044729W WO2025164130A1 WO 2025164130 A1 WO2025164130 A1 WO 2025164130A1 JP 2024044729 W JP2024044729 W JP 2024044729W WO 2025164130 A1 WO2025164130 A1 WO 2025164130A1
Authority
WO
WIPO (PCT)
Prior art keywords
inorganic filler
light
composite
inorganic
mass
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Pending
Application number
PCT/JP2024/044729
Other languages
English (en)
Japanese (ja)
Inventor
英武 坂田
慶 中島
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Tokuyama Dental Corp
Original Assignee
Tokuyama Dental Corp
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Tokuyama Dental Corp filed Critical Tokuyama Dental Corp
Publication of WO2025164130A1 publication Critical patent/WO2025164130A1/fr
Pending legal-status Critical Current
Anticipated expiration legal-status Critical

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Classifications

    • A—HUMAN NECESSITIES
    • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61K—PREPARATIONS FOR MEDICAL, DENTAL OR TOILETRY PURPOSES
    • A61K6/00—Preparations for dentistry
    • A61K6/15—Compositions characterised by their physical properties
    • A61K6/16—Refractive index
    • A—HUMAN NECESSITIES
    • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61K—PREPARATIONS FOR MEDICAL, DENTAL OR TOILETRY PURPOSES
    • A61K6/00—Preparations for dentistry
    • A61K6/15—Compositions characterised by their physical properties
    • A61K6/17—Particle size
    • A—HUMAN NECESSITIES
    • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61K—PREPARATIONS FOR MEDICAL, DENTAL OR TOILETRY PURPOSES
    • A61K6/00—Preparations for dentistry
    • A61K6/60—Preparations for dentistry comprising organic or organo-metallic additives
    • A61K6/62—Photochemical radical initiators
    • A—HUMAN NECESSITIES
    • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61K—PREPARATIONS FOR MEDICAL, DENTAL OR TOILETRY PURPOSES
    • A61K6/00—Preparations for dentistry
    • A61K6/70—Preparations for dentistry comprising inorganic additives
    • A61K6/71—Fillers
    • A—HUMAN NECESSITIES
    • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61K—PREPARATIONS FOR MEDICAL, DENTAL OR TOILETRY PURPOSES
    • A61K6/00—Preparations for dentistry
    • A61K6/70—Preparations for dentistry comprising inorganic additives
    • A61K6/71—Fillers
    • A61K6/76—Fillers comprising silicon-containing compounds
    • A—HUMAN NECESSITIES
    • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61K—PREPARATIONS FOR MEDICAL, DENTAL OR TOILETRY PURPOSES
    • A61K6/00—Preparations for dentistry
    • A61K6/70—Preparations for dentistry comprising inorganic additives
    • A61K6/71—Fillers
    • A61K6/77—Glass
    • A—HUMAN NECESSITIES
    • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61K—PREPARATIONS FOR MEDICAL, DENTAL OR TOILETRY PURPOSES
    • A61K6/00—Preparations for dentistry
    • A61K6/80—Preparations for artificial teeth, for filling teeth or for capping teeth
    • A61K6/884—Preparations for artificial teeth, for filling teeth or for capping teeth comprising natural or synthetic resins
    • A—HUMAN NECESSITIES
    • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61K—PREPARATIONS FOR MEDICAL, DENTAL OR TOILETRY PURPOSES
    • A61K6/00—Preparations for dentistry
    • A61K6/80—Preparations for artificial teeth, for filling teeth or for capping teeth
    • A61K6/884—Preparations for artificial teeth, for filling teeth or for capping teeth comprising natural or synthetic resins
    • A61K6/887—Compounds obtained by reactions only involving carbon-to-carbon unsaturated bonds
    • A—HUMAN NECESSITIES
    • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61K—PREPARATIONS FOR MEDICAL, DENTAL OR TOILETRY PURPOSES
    • A61K6/00—Preparations for dentistry
    • A61K6/80—Preparations for artificial teeth, for filling teeth or for capping teeth
    • A61K6/884—Preparations for artificial teeth, for filling teeth or for capping teeth comprising natural or synthetic resins
    • A61K6/891—Compounds obtained otherwise than by reactions only involving carbon-to-carbon unsaturated bonds
    • A61K6/893—Polyurethanes
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
    • B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
    • B29C64/00—Additive manufacturing, i.e. manufacturing of three-dimensional [3D] objects by additive deposition, additive agglomeration or additive layering, e.g. by 3D printing, stereolithography or selective laser sintering
    • B29C64/30—Auxiliary operations or equipment
    • B29C64/307—Handling of material to be used in additive manufacturing
    • B29C64/314—Preparation
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B33—ADDITIVE MANUFACTURING TECHNOLOGY
    • B33Y—ADDITIVE MANUFACTURING, i.e. MANUFACTURING OF THREE-DIMENSIONAL [3-D] OBJECTS BY ADDITIVE DEPOSITION, ADDITIVE AGGLOMERATION OR ADDITIVE LAYERING, e.g. BY 3-D PRINTING, STEREOLITHOGRAPHY OR SELECTIVE LASER SINTERING
    • B33Y70/00—Materials specially adapted for additive manufacturing
    • B33Y70/10—Composites of different types of material, e.g. mixtures of ceramics and polymers or mixtures of metals and biomaterials
    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08F—MACROMOLECULAR COMPOUNDS OBTAINED BY REACTIONS ONLY INVOLVING CARBON-TO-CARBON UNSATURATED BONDS
    • C08F2/00—Processes of polymerisation
    • C08F2/44—Polymerisation in the presence of compounding ingredients, e.g. plasticisers, dyestuffs, fillers
    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08F—MACROMOLECULAR COMPOUNDS OBTAINED BY REACTIONS ONLY INVOLVING CARBON-TO-CARBON UNSATURATED BONDS
    • C08F2/00—Processes of polymerisation
    • C08F2/46—Polymerisation initiated by wave energy or particle radiation
    • C08F2/48—Polymerisation initiated by wave energy or particle radiation by ultraviolet or visible light
    • C08F2/50—Polymerisation initiated by wave energy or particle radiation by ultraviolet or visible light with sensitising agents
    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08F—MACROMOLECULAR COMPOUNDS OBTAINED BY REACTIONS ONLY INVOLVING CARBON-TO-CARBON UNSATURATED BONDS
    • C08F20/00—Homopolymers and copolymers of compounds having one or more unsaturated aliphatic radicals, each having only one carbon-to-carbon double bond, and only one being terminated by only one carboxyl radical or a salt, anhydride, ester, amide, imide or nitrile thereof
    • C08F20/02—Monocarboxylic acids having less than ten carbon atoms, Derivatives thereof
    • C08F20/10—Esters
    • C08F20/20—Esters of polyhydric alcohols or polyhydric phenols, e.g. 2-hydroxyethyl (meth)acrylate or glycerol mono-(meth)acrylate

Definitions

  • This disclosure relates to a curable composition for three-dimensional stereolithography and a method for producing the same, a method for producing a three-dimensional stereolithography object, and a method for producing a dental restoration.
  • the technology of forming a three-dimensional object by irradiating a photocurable composition also called a photocurable resin or photocurable resin composition
  • a photocurable composition also called a photocurable resin or photocurable resin composition
  • a photopolymerization initiator activates the photopolymerization initiator (activating light) to harden the composition
  • stereolithography There are several stereolithography methods, of which the liquid vat photopolymerization method is widely used because the equipment is relatively inexpensive and it can produce objects with smooth surfaces with high precision.
  • the three-dimensional object to be manufactured is generally obtained as follows. First, the height direction of the three-dimensional object is digitized and ranked from 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 ranked height is generated. Next, activation light is irradiated onto the liquid photocurable composition held in the vat at predetermined positions determined based on the two-dimensional shape data, selectively curing the liquid photocurable composition present at those positions to form a modeling layer with the cross-sectional shape.
  • modeling layers with the cross-sectional shapes at each height are sequentially formed and stacked in the ranked order to obtain a laminate with a shape corresponding to the shape of the three-dimensional object.
  • the laminate is then washed with an organic solvent as needed, and then secondary curing is performed to obtain the desired product.
  • dental restorations such as dentures and crown prostheses must be manufactured with high precision in unique shapes tailored to the oral conditions of each individual patient. For this reason, the production of dental restorations using stereolithography, a liquid vat photopolymerization method, is being considered, based on CAD (Computer Aided Design) data designed using digital data obtained from intraoral scans, etc.
  • CAD Computer Aided Design
  • Dental prostheses used in the oral cavity require not only the high dimensional (shape) accuracy described above, but also high mechanical strength sufficient to withstand the loads exerted during mastication.
  • an inorganic filler when incorporated into a photocurable composition, polymerization shrinkage, which is one of the causes of reduced accuracy, can be reduced, and the mechanical strength and surface hardness of the cured product can be improved.
  • stereolithography of dental prostheses it is believed that liquid vat photopolymerization using a photocurable composition containing an inorganic filler is suitable, and curable compositions for three-dimensional stereolithography containing such inorganic fillers have also been proposed.
  • Patent Document 1 discloses a composition for optical 3D modeling that exhibits excellent molding precision, mechanical properties, and transparency, and is particularly suitable for dental materials.
  • the composition contains a polymerizable monomer (a), ultraviolet-absorbing inorganic particles (b), and a photopolymerization initiator (c).
  • Patent Document 2 discloses a resin composition capable of producing cured products (3D objects) with excellent design potential, the composition containing a translucent resin and two or more types of translucent particles with different refractive indices and Abbe numbers.
  • Patent Document 3 discloses a resin composition for optical 3D modeling that can produce 3D objects with high strength, elasticity, and excellent abrasion resistance.
  • the composition contains a urethane-modified (meth)acrylic compound (a), a (meth)acrylamide compound (b), a photopolymerization initiator (c), and spherical inorganic particles (d) with an average particle size of 0.75 to 10 ⁇ m, with the spherical inorganic particles (d) contained in an amount of 50 to 400 parts by mass per 100 parts by mass of the total amount of polymerizable monomers.
  • Patent Document 4 discloses that an organic-inorganic composite filler containing inorganic agglomerated particles formed by agglomerating inorganic primary particles with an average particle size of 10 to 1,000 nm, an organic resin phase containing a polymerized and cured product of a polymerizable monomer that covers the surface of each inorganic primary particle and bonds each inorganic primary particle to each other, and a water-absorbent resin is added to a dental curable composition, with the aim of reducing the viscosity of the paste, improving workability, suppressing polymerization shrinkage during curing, and improving the mechanical strength of the cured product while maintaining the surface smoothness of the cured product.
  • Patent Documents 1 to 3 use compositions in which inorganic fillers are added to polymerizable monomers, making it possible to obtain molded objects with excellent mechanical strength, elastic modulus, and abrasion resistance.
  • the optical 3D modeling composition described in Patent Document 1 has low fluidity, which may limit the shapes of the objects that can be manufactured.
  • the resin composition described in Patent Document 2 may experience settling of the translucent particles (glass filler, etc.) contained in the composition when left stationary for an extended period of time.
  • the optical 3D modeling resin composition described in Patent Document 3 often causes fine cracks on the surface of the molded object that are difficult to detect with the naked eye (see Figure 4). When a molded object with such fine cracks is used as a dental prosthesis, this poses a problem because it may become the starting point for fracture of the dental prosthesis within the oral cavity.
  • the objective of this disclosure is to provide a technology that enables the production of high-precision, high-strength three-dimensional objects without generating cracks on the surface when producing three-dimensional objects by liquid vat photopolymerization using a curable composition for three-dimensional stereolithography that contains a certain amount of inorganic filler to increase strength.
  • a first aspect of the present disclosure provides a three-dimensional optically shaped object produced in a liquid tank photopolymerization method in which a predetermined position of a liquid photocurable composition held in a tank is irradiated with activating light (hereinafter also referred to as "specific activating light") containing light of a specific wavelength ⁇ (nm) in the ultraviolet or visible light region to selectively cure the liquid photocurable composition present at that position, the method comprising:
  • the composition contains 100 parts by mass of a polymerizable monomer component (A), 40 to 400 parts by mass of an inorganic filler (B) composed of a single type or multiple types of inorganic powder or particles, 0.01 to 5 parts by mass of a photopolymerization initiator (C) having a function of initiating photopolymerization upon irradiation with specific activating light, and 0.01 to 2.5 parts by mass of an activating light absorber (D) having a function of absorbing the specific activating light but not having photopolymerization
  • the polymerizable monomer component (A), the non-composite inorganic filler (B1), and the organic-inorganic composite filler (E) are When a composition consisting of only the polymerizable monomer component (A), the non-composite inorganic filler (B1), and the organic-inorganic composite filler (E), in which the compositional ratio of these components is the same as that of the curable composition for three-dimensional stereolithography of the present disclosure, is used as a base composition, a 0.5 mm thick sample made of the base composition is measured using a goniophotometer that irradiates the sample perpendicularly with measurement light that includes light of the specific wavelength ⁇ (nm), is mainly composed of light within a range of ⁇ 50 (nm), and exhibits the
  • a second aspect of the present disclosure is a method for producing a curable composition for three-dimensional optical fabrication according to the present disclosure, comprising: The method includes a mixing step of mixing a polymerizable monomer component (A), a non-composite inorganic filler (B1), an organic-inorganic composite filler (E), a photopolymerization initiator (C), and an activated light absorber (D),
  • the refractive index of the polymerizable monomer component (A) at 25°C to the D line and the refractive index of the specific activating light at 25°C are respectively n (D)M and n (AL)M
  • the light scattering index determined by the above formula: Sc (%) is 10 (%) or less; This is a method for producing a curable composition for three-dimensional stereolithography, in which a composition that has been confirmed to satisfy all of the above requirements is used.
  • a third aspect of the present disclosure is a method for producing a three-dimensional optically shaped object by irradiating a predetermined position of a liquid photocurable composition held in a tank with specific activating light to selectively cure the liquid photocurable composition present at the predetermined position, the method comprising: a molding process in which, from three-dimensional shape data representing the shape of a three-dimensional object, the height direction of the three-dimensional object is digitized and ranked, and two-dimensional shape data representing the cross-sectional shape of the three-dimensional object at each ranked height is generated; specific activating light is applied to a liquid photocurable composition held in a tank at a predetermined position determined in advance based on the two-dimensional shape data, thereby selectively and primarily curing the liquid photocurable composition present at that position to form a modeling layer having the cross-sectional shape; and modeling layers having the cross-sectional shapes at each height are sequentially formed and stacked in the ranked order to obtain a laminate having a shape corresponding to the shape of the
  • a fourth aspect of the present disclosure is a method for manufacturing a dental restoration, which includes manufacturing a dental restoration using the method for manufacturing a three-dimensional optically shaped object of the present disclosure.
  • the disclosed curable composition for three-dimensional stereolithography contains a certain amount of inorganic filler to increase strength, yet has the fluidity to allow it to be modeled using a three-dimensional stereolithography device.
  • the disclosed method for manufacturing a three-dimensional stereolithography object using this curable composition for three-dimensional stereolithography makes it possible to manufacture a three-dimensional stereolithography object with excellent mechanical strength and shape precision while preventing cracks from occurring on the surface.
  • FIG. 10 is a diagram showing an optical microscope image (magnification: 50 times) of the surface of the three-dimensional optically shaped object obtained in Reference Example 7 (evaluation: A0).
  • FIG. 11 is a diagram showing an optical microscope image (magnification: 50 times) of the surface of the three-dimensional optically shaped object obtained in Reference Example 11 (evaluation B).
  • FIG. 1 is a diagram showing an optical microscope image (magnification: 50 times) of the surface of the three-dimensional optically shaped object obtained in Reference Comparative Example 1 (evaluation D).
  • FIG. 10 is a diagram showing an optical microscope image (magnification: 50 times) of the surface of the three-dimensional optically shaped object obtained in Reference Comparative Example 9 (evaluation C).
  • FIG. 1 is a graph showing the wavelength distribution of measurement light used when measuring the light scattering index Sc in Examples and Reference Examples.
  • FIG. 2 is a diagram showing an optical microscope image (magnification: 50 times) of the surface of the three-dimensional optically shaped object obtained in Example 1 (evaluation A1).
  • the curable composition for three-dimensional stereolithography of the present disclosure (hereinafter also simply referred to as the "curable composition for stereolithography") is a composition used as a liquid photocurable composition when producing a three-dimensional object using a liquid vat photopolymerization method, i.e., a curable composition for three-dimensional stereolithography by a liquid vat photopolymerization method.
  • the liquid vat photopolymerization method refers to a process that includes the steps of: digitizing and ranking the height direction of a three-dimensional object from three-dimensional shape data that indicates the shape of the three-dimensional object; generating two-dimensional shape data that indicates the cross-sectional shape of the three-dimensional object at each ranked height; irradiating a liquid photocurable composition held in a vat with activating light at predetermined positions determined in advance based on the two-dimensional shape data, thereby selectively (primarily) curing the liquid photocurable composition present at those positions to form modeling layers with the cross-sectional shape; and sequentially forming and stacking modeling layers with the cross-sectional shapes at each height in the ranked order to obtain a laminate with a shape corresponding to the shape of the three-dimensional object (hereinafter also referred to as the "molding process").
  • a cleaning process with an organic solvent hereinafter also referred to as the "cleaning process” or a secondary curing process (hereinafter also referred to as the “secondary curing process”) is performed to obtain a three-dimensional photo-fabricated object with a shape corresponding to the shape of the three-dimensional object.
  • photocurable compositions that contain a certain amount of inorganic filler to improve the mechanical strength and surface hardness of the cured product can suffer from problems such as reduced fluidity and particle settling during storage. Furthermore, when a model is produced using the liquid tank photopolymerization method using the stereolithography resin composition described in Patent Document 3, fine cracks that are difficult to detect with the naked eye often occur on the surface of the model (although this is not recognized in Patent Document 3).
  • the inventors have confirmed that cracks occur when uncured curable composition adhering to the surface of a laminate obtained using a stereolithography device is washed with an organic solvent. Furthermore, the inorganic filler contained in the curable composition for stereolithography contains many particles with particle sizes that cause scattering (specifically, Mie scattering or Reyleigh scattering) when irradiated with activating light. This generates weak activating light (sideward scattered light) that is scattered off the optical axis of the irradiation spot, resulting in an extremely shallow cure depth. This is thought to be one of the causes of cracks.
  • the organic solvent penetrates the interlayer low crosslink density region during washing, causing the region to swell, widening the molecular spacing of the polymer chains that make up the molded product and temporarily reducing its strength. It is thought that this is when internal stress remaining in the molded product during the molding process destroys the weakened portion, resulting in cracks in the region.
  • the inventors have discovered that these problems can be solved by controlling the particle size of the particles that make up the inorganic filler and by setting the transmittance of the specific activating light in the composition before curing to a specific range, and have proposed a novel curable composition for three-dimensional stereolithography (Japanese Patent Application No. 2023-018503). Furthermore, as a preferred embodiment, they have proposed a curable composition for three-dimensional stereolithography (hereinafter also referred to as the "already proposed curable composition”) that has the following features 1 to 4.
  • Feature 1 Contains 100 parts by mass of polymerizable monomer component (A), 40 to 400 parts by mass of inorganic filler (B) composed of a single type or multiple types of inorganic powder and granules, 0.01 to 5 parts by mass of photopolymerization initiator (C) that has the function of initiating photopolymerization upon irradiation with specific activating light, and 0.01 to 2.5 parts by mass of activating light absorber (D) that has the function of absorbing specific activating light but does not have the ability to initiate photopolymerization.
  • A polymerizable monomer component
  • B inorganic filler
  • C photopolymerization initiator
  • D activating light absorber
  • Feature 2 In the particle size distribution of inorganic filler (B) measured by microscopy using a scanning microscope, 80% or more of all primary particles constituting said inorganic filler (B) have a particle diameter of 0.05 to 5.0 ⁇ m.
  • Feature 3 The transmittance of a specific activating light measured on a 0.5 mm thick sample made of the curable composition for three-dimensional optical fabrication is 1 to 50%.
  • the proposed curable composition by containing a polymerizable monomer component and an inorganic filler in a quantitative ratio that satisfies the condition set forth in Feature 1, it is possible to increase the strength and surface hardness of the cured body that will become the three-dimensional optically shaped object that is the target of manufacture. Furthermore, by having the particles that make up the inorganic filler satisfy the condition set forth in Feature 2 in terms of particle size, it is possible to reduce the risk of an increase in viscosity of the composition and particle settling during storage. Furthermore, by satisfying the conditions set forth in Feature 3 and 4, it is possible to achieve the effects of high strength, prevention of cracking, and high precision.
  • the inventors investigated applying the technology disclosed in Patent Document 4 to incorporate part of the inorganic filler (B) as an organic-inorganic composite filler composed of particles made of a composite in which inorganic powder particles are dispersed in a resin matrix. As a result, they found that while it was possible to improve the fluidity, the crack prevention effect, which is a characteristic of the previously proposed curable composition, could be impaired.
  • the curable composition for stereolithography disclosed herein has the following characteristics [1] to [5], due to the organic-inorganic composite filler being an essential component.
  • the fluidity of the composition is further improved while maintaining the characteristics of previously proposed curable compositions, namely, "there is little risk of a decrease in fluidity or sedimentation of the inorganic filler, and the occurrence of cracks on the surface is prevented, while allowing the production of three-dimensional stereolithography objects with excellent mechanical strength and good shape precision.”
  • Feature [1] (same as feature 1 above): Contains 100 parts by mass of polymerizable monomer component (A), 40 to 400 parts by mass of inorganic filler (B) composed of a single type or multiple types of inorganic powder and granules, 0.01 to 5 parts by mass of photopolymerization initiator (C) that has the function of initiating photopolymerization upon irradiation with specific activating light, and 0.01 to 2.5 parts by mass of activating light absorber (D) that has the function of absorbing specific activating light but does not have the ability to initiate photopolymerization.
  • A polymerizable monomer component
  • B inorganic filler
  • C photopolymerization initiator
  • D activating light absorber
  • Feature [2] (same as feature 2 above): In the particle size distribution of inorganic filler (B) measured by microscopy using a scanning microscope, 80% or more of all primary particles constituting said inorganic filler (B) have a particle diameter of 0.05 to 5.0 ⁇ m.
  • organic-inorganic composite filler (E) consisting of particles formed from a composite material of the inorganic filler (B) and a resin (R).
  • inorganic filler (B) that is not composited with the resin (R) is defined as a non-composite inorganic filler (B1) and inorganic filler included as the organic-inorganic composite filler (E) is defined as a composite inorganic filler (B2)
  • both the non-composite inorganic filler (B1) and the composite inorganic filler (B2) satisfy the condition of feature [2].
  • compositions and particle size distributions of the non-composite inorganic filler (B1) and the composite inorganic filler (B2) may be the same or different.
  • inorganic powder particles prepared as inorganic filler (B) or prepared by mixing multiple types of inorganic powder particles
  • it is preferable that the composition, particle size distribution, and average primary particle diameter of both are the same or substantially the same.
  • Feature [4] (corresponding to the above-mentioned feature 4):
  • Feature [5] (same as feature 3 above): The transmittance to specific activating light measured on a 0.5 mm thick sample made of the curable composition for three-dimensional optical fabrication is 1 to 50%.
  • the curable composition for stereolithography disclosed herein contains 100 parts by mass of a polymerizable monomer component (A), 40 to 400 parts by mass of an inorganic filler (B) composed of a single type or multiple types of inorganic powder or particles, 0.01 to 5 parts by mass of a photopolymerization initiator (C) that has the function of initiating photopolymerization upon irradiation with specific activating light, and 0.01 to 2.5 parts by mass of an activating light absorber (D) that has the function of absorbing the specific activating light but does not have the ability to initiate photopolymerization.
  • A polymerizable monomer component
  • B inorganic filler
  • C photopolymerization initiator
  • D an activating light absorber
  • the polymerizable monomer component (A) It is preferable to use a (meth)acrylate monomer as the polymerizable monomer component (A) because it has a fast curing rate and the strength of the resulting shaped object is excellent. In order to produce a shaped object with even higher strength, it is preferable that 50% by mass or more, preferably 80% by mass or more, and more preferably 95% by mass or more of the polymerizable monomers be a bifunctional or higher polyfunctional (meth)acrylate, based on the total mass of all radically polymerizable monomers.
  • Suitable examples of difunctional or higher polyfunctional (meth)acrylates include (meth)acrylates containing a bisphenol A skeleton, 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.
  • bisphenol A skeleton 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)acryloyloxypolyethoxy
  • Suitable acrylates include aliphatic di(meth)acrylates such as 1,3-propanediol di(meth)acrylate and 1,9-nonanediol dimethacrylate; urethane group-containing (meth)acrylates such as 1,6-bis(methacryloyloxy-2-ethoxycarbonylamino)-2,2,4-trimethylhexane; trifunctional (meth)acrylates such as trimethylolpropane trimethacrylate; and isocyanate skeleton-containing (meth)acrylates such as tris(2-methacryloyloxyethyl)isocyanurate.
  • aliphatic di(meth)acrylates such as 1,3-propanediol di(meth)acrylate and 1,9-nonanediol dimethacrylate
  • urethane group-containing (meth)acrylates such as 1,6-bis(methacryloyloxy-2-ethoxycarbonylamin
  • 2,2'-bis[4-(meth)acryloyloxyphenyl]propane, 2,2'-bis[4-(meth)acryloyloxypolyethoxyphenyl]propane, triethylene glycol dimethacrylate, and tris(2-methacryloyloxyethyl)isocyanurate are preferred due to their low viscosity and high strength.
  • examples of monofunctional (meth)acrylates suitable for use in combination with difunctional or higher polyfunctional (meth)acrylates include hydroxyethyl methacrylate, methyl (meth)acrylate, ethyl (meth)acrylate, isopropyl (meth)acrylate, hydroxyethyl (meth)acrylate, tetrahydrofurfuryl (meth)acrylate, and glycidyl (meth)acrylate.
  • polymerizable monomer component (A) one of these (meth)acrylates may be used alone, or multiple types may be used in combination.
  • the curable composition for stereolithography contains 40 to 400 parts by mass of the inorganic filler (B) per 100 parts by mass of the polymerizable monomer component (A). If the content of the inorganic filler (B) is too high, the viscosity of the composition will be too high. On the other hand, if the content of the inorganic filler (B) is too low, the mechanical strength will be insufficient. For this reason, the content of the inorganic filler (B) is preferably 50 to 350 parts by mass, more preferably 60 to 300 parts by mass, per 100 parts by mass of the polymerizable monomer component (A).
  • the particle size distribution of inorganic filler (B) measured by microscopy using a scanning microscope must be such that 80% or more (preferably 90% or more, more preferably 95% or more) of all primary particles constituting inorganic filler (B) have a particle diameter of 0.05 to 5.0 ⁇ m.
  • the fact that 80% or more of all primary particles constituting the inorganic filler (B) have a particle diameter of 0.05 to 5.0 ⁇ m can be confirmed by the particle size distribution of the inorganic filler (B) measured by microscopy using a scanning microscope. That is, the inorganic filler (B) is photographed using a scanning electron microscope, and the number n (of all primary particles) (50 or more) observed within a unit field of view of the photograph is measured, and the primary particle diameter (maximum diameter): Xi (nm) of each particle is measured for all particles, thereby determining the particle size distribution.
  • i in the above Xi is a natural number from 1 to n, and represents the number of each measured primary particle.
  • the average primary particle diameter of the inorganic filler (B) is preferably 0.07 to 3 ⁇ m, and more preferably 0.08 to 1 ⁇ m.
  • inorganic filler (B) By including inorganic filler (B) having such a particle size distribution in the above-mentioned ratio, it is possible to increase the strength and surface hardness of the cured body that will become the three-dimensional photo-fabricated object, which is the target product. Furthermore, by having the particles constituting inorganic filler (B) satisfy the above-mentioned particle diameter conditions, it is possible to suppress an increase in viscosity of the composition and the risk of particle settling during storage. To further suppress an increase in viscosity, the lower limit of the particle diameter of particles that account for 80% or more of inorganic filler (B) is preferably 0.08 ⁇ m, and more preferably 0.1 ⁇ m. To further suppress settling, the upper limit of the particle diameter of particles that account for 80% or more of inorganic filler (B) is preferably 2.0 ⁇ m, and more preferably 1.0 ⁇ m.
  • Inorganic filler (B) may be contained as aggregated particles formed by aggregation of primary particles. As long as the particle size distribution of the primary particles satisfies the above conditions, the particle size distribution of the aggregated particles is not particularly limited. However, in order to suppress sedimentation of inorganic filler (B), it is preferable that the number of aggregated particles of inorganic filler (B) contained in the curable composition for stereolithography of the present disclosure be small.
  • the average particle size of inorganic filler (B) including aggregated particles of primary particles measured by laser diffraction/scattering is typically 0.05 to 100 ⁇ m, preferably 0.05 to 50 ⁇ m, and more preferably 0.05 to 30 ⁇ m.
  • inorganic filler (B) is divided into non-composite inorganic filler (B1) that is blended in as is without being composited with resin (R), and composite inorganic filler (B2) that is blended as organic-inorganic composite filler (E), and therefore the above blending amount of inorganic filler (B) means the combined blending amount of non-composite inorganic filler (B1) and composite inorganic filler (B2) per 100 parts by mass of polymerizable monomer component (A).
  • the inorganic filler (B) is composite inorganic filler (B2), and the remainder is non-composite inorganic filler (B1). If the proportion of composite inorganic filler (B2) in the inorganic filler (B) is too high, fluidity will be significantly reduced. On the other hand, if the proportion of composite inorganic filler (B2) in the inorganic filler (B) is too low, it will be difficult to achieve the fluidity-improving effect achieved by adding organic-inorganic composite filler (E). For this reason, the proportion of composite inorganic filler (B2) in the inorganic filler (B) is preferably 20 to 80 mass%, and more preferably 30 to 70 mass%.
  • the non-composite inorganic filler (B1) and the composite inorganic filler (B2) 80% or more (preferably 90% or more, more preferably 95% or more) of all the primary particles that make up the filler are particles with a particle diameter of 0.05 to 5.0 ⁇ m.
  • the compositions and particle size distributions of the non-composite inorganic filler (B1) and the composite inorganic filler (B2) may be the same or different, but since inorganic powder particles prepared as inorganic filler (B) (or prepared by mixing multiple types of inorganic powder particles, etc.) are typically used separately, it is preferable that the composition, particle size distribution, and average primary particle diameter of both fillers be the same or substantially the same. Note that "substantially the same” basically means that the difference is within the range of measurement error.
  • inorganic powders and granules used as inorganic fillers in dental restorative materials can be used without particular restrictions, provided that they satisfy the conditions set forth in characteristic point [5] and also satisfy the conditions set forth in characteristic point [4]. Because these prerequisites are easily met, inorganic powders and granules composed of particles of amorphous silica; silica-based composite oxides such as silica-zirconia, silica-titania, silica-titania-barium oxide, and silica-titania-zirconia; and glasses such as borosilicate glass, aluminosilicate glass, and fluoroaluminosilicate glass are preferred.
  • silica-based composite oxides such as silica-zirconia, silica-titania, silica-titania-barium oxide, and silica-titania-zirconia.
  • silica-zirconia particles from the standpoint of the abrasion resistance of the cured body, it is even more preferred to use particles composed of silica-zirconia particles.
  • any surface treatment agent such as a silane coupling agent
  • any surface treatment agent such as a silane coupling agent
  • silane coupling agents include methyl trimoxysilane, methyl triethoxysilane, methyl trichlorosilane, dimethyl dichlorosilane, trimethyl chlorosilane, vinyl trichlorosilane, vinyl triethoxysilane, vinyl tris( ⁇ -methoxyethoxy)silane, ⁇ -methacryloyloxypropyl trimethoxysilane, methacryloyloxyoctyl-8-trimethoxysilane, ⁇ -chloropropyl trimethoxysilane, ⁇ -glycidoxypropyl methoxysilane, and hexamethyldisilazane.
  • the photopolymerization initiator (C) must have the ability to generate radicals and radically polymerize the polymerizable monomer component when exposed to specific activating light, including light of a specific wavelength ⁇ (nm) in the ultraviolet or visible light region, irradiated from a light source installed in the stereolithography device.
  • the photopolymerization initiator (C) must absorb light of a specific wavelength ⁇ (nm) to generate radicals.
  • the specific wavelength ⁇ as long as it is in the ultraviolet or visible light region, may be appropriately determined depending on the wavelength of the activating light used in the stereolithography device.
  • Examples of general-purpose stereolithography devices include SLA-type stereolithography devices that irradiate semiconductor laser light as the activating light, DLP-type stereolithography devices that irradiate projector light, and LCD-type stereolithography devices that irradiate liquid crystal panel light, and the like.
  • Light sources with activating light wavelengths of 405 nm or 385 nm are often used.
  • the specific wavelength ⁇ is preferably 405 nm or 385 nm
  • the optical shaping apparatus is preferably an SLA type, a DLP type, or an LCD type.
  • the amount of photopolymerization initiator (C) to be blended should be 0.05 to 5.0 parts by mass per 100 parts by mass of polymerizable monomer component (A). If the amount of photopolymerization initiator (C) to be blended is too high, burrs and other imperfections will appear on the resulting molded object, resulting in poor precision. On the other hand, if the amount of photopolymerization initiator (C) to be blended is too low, it will be impossible to form a shape in the molding process. For this reason, the amount of photopolymerization initiator (C) to be blended should preferably be 0.3 to 4.0 parts by mass, and more preferably 0.5 to 3.0 parts by mass, per 100 parts by mass of polymerizable monomer component (A).
  • the photopolymerization initiator (C) may be appropriately selected from known photopolymerization initiators that satisfy the above conditions. There are no particular restrictions on the photopolymerization initiator to be selected, and examples include self-cleavage photopolymerization initiators, bimolecular hydrogen abstraction photopolymerization initiators, photoacid generators, and combinations of these. These photopolymerization initiators may also be used in combination with photosensitizing dyes, electron-donating compounds, etc.
  • Suitable self-cleaving photopolymerization initiators include acylphosphine oxide compounds such as diphenyl(2,4,6-trimethylbenzoyl)phosphine oxide and phenylbis(2,4,6-trimethylbenzoyl)phosphine oxide; benzoketal compounds, benzyne compounds, ⁇ -aminoacetophenone compounds, ⁇ -hydroxyacetophenone compounds, titanocene compounds, and acyloxime compounds.
  • Photoacid generators include iodonium salt compounds such as p-isopropylphenyl-p-methylphenyliodonium tetrakispentafluorophenylborate salt; sulfonium salt compounds such as dimethylphenacylsulfonium hexafluoroantimonate salt; and halomethyl-substituted triazine compounds such as 2,4,6-tris(trichloromethyl)-s-triazine.
  • iodonium salt compounds such as p-isopropylphenyl-p-methylphenyliodonium tetrakispentafluorophenylborate salt
  • sulfonium salt compounds such as dimethylphenacylsulfonium hexafluoroantimonate salt
  • halomethyl-substituted triazine compounds such as 2,4,6-tris(trichloromethyl)-s-triazine.
  • Photosensitizing dyes include ketone compounds, coumarin dyes, cyanine dyes, merocyanine dyes, thiazine dyes, azine dyes, acridine dyes, xanthene dyes, squarium dyes, pyrylium salt dyes, condensed polycyclic aromatic compounds (anthracene, perylene, etc.), and thioxanthone compounds.
  • Electron donors include 4-dimethylaminobenzoic acid esters, 4-dimethylaminotoluene, p-dimethoxybenzene, 1,2,4-trimethoxybenzene, and thiophene compounds.
  • Activating Light Absorber (D) When a molded product such as a dental prosthesis is produced with high precision using the curable composition for stereolithography of the present disclosure, in order to prevent excessive transmission of the activating light irradiated from the stereolithography device, which would result in a decrease in the modeling precision of the molded product, 0.01 to 2.5 parts by mass of an activating light absorber (D) that has the function of absorbing the activating light irradiated from the stereolithography device but does not function as a photopolymerization initiator is blended per 100 parts by mass of the polymerizable monomer component.
  • the amount of activated light absorber (D) is preferably 0.04 to 2.5 parts by mass, more preferably 0.08 to 2.0 parts by mass, and even more preferably 0.25 to 1.0 parts by mass, per 100 parts by mass of the polymerizable monomer component.
  • the activated light absorber (D) is not particularly limited as long as it is a compound that absorbs light irradiated from a light source installed in the stereolithography device, and 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 the like.
  • Organic-inorganic composite powder/particle (E) As described in characteristic point [3], the composite inorganic filler (B2) occupies 10 to 90 mass %, preferably 20 to 80 mass %, more preferably 30 to 70 mass % of the inorganic filler (B) and is blended as the organic-inorganic composite filler (E).
  • the organic-inorganic composite filler refers to a powder or granule composed of particles formed from a composite material of a composite inorganic filler (B2) and a resin (R).
  • the composite material include a first form in which the composite inorganic filler (B2) is uniformly dispersed in a matrix of the resin (R); and a second form in which the surface of each inorganic primary particle forming the composite inorganic filler (B2) is covered with a resin and the inorganic primary particles are bonded to each other by the resin to form (microporous) aggregated particles.
  • the content of the composite inorganic filler (B2) and the resin (R) in the composite material is preferably 50 to 99% by mass, and more preferably 70 to 95% by mass.
  • the average particle diameter of the organic-inorganic composite filler (E), specifically, the average particle diameter measured by laser diffraction/scattering, is preferably 0.5 to 100 ⁇ m, more preferably 1 to 50 ⁇ m, and even more preferably 2 to 30 ⁇ m.
  • the organic-inorganic composite fillers of the first and second forms can be produced using inorganic powder and particles and a polymerizable monomer component that serves as a raw material for the resin (R), and the organic-inorganic composite filler (E) can also be produced using a composite inorganic filler (B2) and a polymerizable monomer component that serves as a raw material for the resin (R).
  • the polymerizable monomer component is preferably one of those exemplified as the polymerizable monomer component (A), but it does not have to be the same as the polymerizable monomer component (A).
  • a polymerization inhibitor is preferably blended in the range of 0.01 to 5.0 parts by mass relative to 100 parts by mass of the polymerizable monomer component (A). If the blended amount of polymerization inhibitor is too high, the composition will not cure sufficiently during the molding process. On the other hand, if the blended amount of polymerization inhibitor is too low, the storage stability and molding accuracy will decrease. For this reason, the blended amount of polymerization inhibitor is preferably 0.01 to 5.0 parts by mass, more preferably 0.03 to 4.0 parts by mass, and even more preferably 0.05 to 2.5 parts by mass relative to 100 parts by mass of the polymerizable monomer component (A).
  • the polymerization inhibitor can be a compound that reacts with radicals generated in the curable composition for stereolithography to deactivate the radicals, such as di-tert-butyl-p-cresol and 4-methoxyphenol.
  • the curable composition for stereolithography may contain a chain transfer agent in an amount ranging from 0.00001 to 1.0 part by mass per 100 parts by mass of the polymerizable monomer component (A) for the purposes of reducing shrinkage stress during stereolithography and improving modeling accuracy. If the amount of chain transfer agent is too large, the polymerization reaction of the curable composition for stereolithography will be suppressed more than necessary, whereas if the amount of chain transfer agent is too small, the effect of adding the chain transfer agent will not be obtained.
  • chain transfer agents examples include thiol compounds such as butanethiol, thiophenol, mercaptoethanol, octylthiol, and lauryl mercaptan; ⁇ -alkylstyrene compounds such as 2,4-diphenyl-4-methyl-1-pentene ( ⁇ -methylstyrene dimer) and 2-phenyl-1-propene ( ⁇ -methylstyrene); and halogenated hydrocarbons substituted with at least one halogen atom, such as carbon tetrachloride and ethylene bromide. Of these, it is preferable to use ⁇ -alkylstyrene compounds, especially ⁇ -methylstyrene dimer, because of their high crack suppression effect.
  • thiol compounds such as butanethiol, thiophenol, mercaptoethanol, octylthiol, and lauryl mercaptan
  • ⁇ -alkylstyrene compounds such as 2,
  • the curable composition for stereolithography according to the present disclosure may contain a thermal polymerization initiator as a polymerization initiator for secondary curing.
  • a thermal polymerization initiator with a 10-hour half-life temperature of 50 to 130°C, as it does not function during primary curing and remains effectively in the laminate.
  • Suitable thermal polymerization initiators include organic peroxides such as tert-butyl peroxylaurate and benzoyl peroxide; azo compounds such as azobutyronitrile and azobis(dimethylvaleronitrile); and the like.
  • the amount of thermal polymerization initiator added is typically 0.001 to 1.0 part by mass, preferably 0.005 to 0.3 part by mass, and more preferably 0.01 to 0.1 part by mass, per 100 parts by mass of polymerizable monomer component (A).
  • the stereolithography curable composition of the present disclosure may contain a coloring substance within the range satisfying the conditions described in Features [4] and [5].
  • a coloring substance may be a pigment or a dye.
  • pigments include inorganic pigments such as titanium oxide, zinc oxide, zirconium oxide, zinc sulfide, aluminum silicate, calcium silicate, carbon black, iron oxide, copper chromite black, chromium oxide green, chrome green, violet, chrome yellow, lead chromate, lead molybdate, cadmium titanate, nickel titanium yellow, ultramarine blue, cobalt blue, bismuth vanadate, cadmium yellow, and cadmium yellow; and organic pigments such as monoazo pigments, diazo pigments, diazo condensation pigments, perylene pigments, and anthraquinone pigments.
  • inorganic pigments such as titanium oxide, zinc oxide, zirconium oxide, zinc sulfide, aluminum silicate, calcium silicate, carbon black, iron oxide, copper chromite black, chromium oxide green, chrome green, violet, chrome yellow, lead chromate, lead molybdate, cadmium titanate, nickel titanium yellow, ultramarine blue, cobalt blue, bismut
  • the composition is characterized by employing a combination of polymerizable monomer component (A), non-composite inorganic filler (B1), and organic-inorganic composite filler (E) that results in a light scattering index Sc within a specific range.
  • curable composition for photopolymerization With the curable composition for photopolymerization disclosed herein, light scattering by the inorganic filler in directions off the optical axis is suppressed, and by setting the transmittance for specific activating light (before photocuring) within a specific range, cracking can be prevented and, in some cases, modeling precision can be further improved.
  • the conditions set forth in features [4] and [5] define the conditions to be satisfied by the polymerizable monomer component (A), inorganic filler (B), photopolymerization initiator (C), activating light absorber (D), and organic-inorganic composite filler (E).
  • the transmittance defined in feature [5] corresponds to the "transmittance of the curable composition for photolithography of the present disclosure to specific activating light before photocuring," and serves as an indicator of the depth of cure when the curable composition for photolithography of the present disclosure is irradiated with specific activating light.
  • Sc defined in feature [4] defines the "scattering state of light when the curable composition for photolithography of the present disclosure is irradiated with specific activating light," specifically, the state of side-scattered light, and ultimately serves as an indicator of the extent of the interlayer low-crosslink density region formed thereby.
  • the cure depth and the state of side-scattered light are important in achieving the effects of the curable composition for photolithography of the present disclosure, and are determined by the combination of the components used.
  • the physical properties of each component that affect transmittance and Sc are not only diverse but also influenced by their relationships with the physical properties of other components, it is virtually impossible to directly define a specific combination of substances that satisfies these conditions.
  • the curable composition for stereolithography disclosed herein is defined as one that simultaneously satisfies the conditions set forth in features [4] and [5]. As such, it is virtually impossible to define the curable composition for stereolithography disclosed herein solely by its composition, such as the components that make it up and their blending amounts. It must be defined either by the parameters set forth in features [4] and [5], or as a curable composition for stereolithography obtained by the manufacturing method disclosed herein.
  • Feature [4] It is generally known that when light is irradiated onto fine particles with a particle size suitable for a stereolithography resin composition, i.e., fine particles with a particle size of 0.05 to 5.0 ⁇ m, phenomena such as light blocking, diffraction, Mie scattering, and Rayleigh scattering occur. Among these, when Mie scattering and/or Rayleigh scattering occurs, the scattered light spreads not only forward but also to the sides and rear. Furthermore, the scattered light that spreads to the sides (sideward scattered light) reduces the transmittance of the specific activation light in Feature [5], which is thought to cause cracks and further reduce the molding accuracy of the molded product.
  • the spread and intensity of side-scattered light i.e., the intensity distribution of scattered light with respect to the scattering direction (angle) are affected not only by the particle size of the particles, but also by the refractive index of the particles and the polymerizable monomer components present around the particles (as a dispersion medium).
  • a dispersion system in which particles are dispersed in a polymerizable monomer component as a powder with a particle size distribution, particularly in a dispersion system composed of multiple types of particles with different refractive indices, it is virtually impossible to grasp the scattering behavior of each particle; it is necessary to grasp the scattering behavior of the entire system.
  • the disclosed curable composition for photolithography when used in the manufacture of dental prosthetic materials, the greater the average "intensity of activation light scattered sideways" of the entire system, the lower the modeling accuracy, and further the transmittance of specific activation light, raising concerns about the occurrence of cracks due to an increase in interlayer low-crosslink density regions.
  • the combination of polymerizable monomers, non-composite inorganic fillers, and organic-inorganic composite fillers used in the curable composition for stereolithography of the present disclosure is indirectly defined using the light scattering index Sc (%) defined by the above formula in the base composition (a homogeneous base composition consisting only of polymerizable monomers, non-composite inorganic fillers, and organic-inorganic composite fillers in a specified quantitative ratio) that forms the base of the curable composition for stereolithography of the present disclosure.
  • Measuring the refracted light passing through a sample using a goniophotometer is used to evaluate the optical properties of materials that require light diffusion, such as lighting fixture covers and projector screens.
  • it is also used as an index for evaluating the optical texture of dental filling and restorative materials, specifically to determine the degree of diffusion D.
  • measurements using a goniophotometer to determine the light scattering index Sc can be performed as follows. First, a portion of the base composition (for raw materials) prepared during the preparation process of the curable composition for stereolithography disclosed herein is sampled, or a base composition (for measurement) prepared by separate preparation is used to prepare a measurement sample with a thickness of 0.5 mm in the same manner as for transmittance measurement.
  • the sample is placed in a three-dimensional goniophotometer (e.g., GP-200, manufactured by Murakami Color Research Laboratory Co., Ltd.), and measurement light containing light of a specific wavelength: ⁇ (nm), primarily composed of light within a range of ⁇ ⁇ 50 (nm), and exhibiting maximum intensity within that range is irradiated perpendicularly onto the sample, and the intensity of the transmitted light at each exit angle is measured.
  • a three-dimensional goniophotometer e.g., GP-200, manufactured by Murakami Color Research Laboratory Co., Ltd.
  • an interference filter for example, an interference filter for the GP-200, manufactured by Murakami Color Research Laboratory Co., Ltd.
  • light within the ⁇ 50 (nm) range is the main component means that in the spectrum showing the wavelength distribution (relative spectral distribution) of the measurement light, the integrated value of the intensity of light with wavelengths of ⁇ 50 (nm) is 90% or more of the integrated value of the intensity of the entire measurement light.
  • the light scattering index Sc of the base composition exceeds 10%, the formation of interlayer low crosslink density regions that cause cracks due to side scattered light is unavoidable.
  • the light scattering index Sc of the base composition is preferably 5.0% or less, and more preferably 3.0% or less. The lower the light scattering index Sc, the better, with the lower limit being 0.0%.
  • the light scattering index Sc of the base composition is affected by the blending ratio of the polymerizable monomer component (A), non-composite inorganic filler (B1), and organic-inorganic composite filler (E). However, when these ratios are constant, it can be controlled to some extent by adjusting the particle size distribution of the non-composite inorganic filler (B1) and the composite inorganic filler (B2) in the organic-inorganic composite filler (E), the refractive index (or type) of the particles that make up the inorganic powder or granules, as well as the refractive index of the polymerizable monomer component as a whole and the refractive index of the resin (R) in the organic-inorganic composite filler (E).
  • particle size parameter ⁇ that serves as an index of the scattering and scattering intensity of light caused by particles.
  • Many dental inorganic fillers have particle sizes smaller than this value, so the scattering occurs and cracks are likely to occur.
  • the inorganic filler (B) used i.e., the non-composite inorganic filler (B1) and the composite inorganic filler (B2), satisfy the following condition 1.
  • Condition 1 When the particle diameter of each primary particle constituting the inorganic filler (B) is x (nm) and pi is ⁇ , in the particle size distribution of the inorganic filler (B) measured by microscopy using a scanning microscope, the total number of particles having a particle diameter x (nm) within the range of 0.7 ⁇ / ⁇ to 4 ⁇ / ⁇ (nm) accounts for 40% or more, preferably 60% or more, and more preferably 80% or more of the total number of primary particles constituting the inorganic filler (B).
  • the proportion of particles in the inorganic filler (B) with particle diameters in which the particle diameter parameter ⁇ is in the range of 1.0 to 3.0 (129 to 386 nm when the wavelength of the activating light is 405 nm) is preferably 50% or more, and more preferably 60% or more, and the proportion of particles with particle diameters in which the particle diameter parameter ⁇ is in the range of 1.8 to 2.8 (231 to 360 nm when the wavelength of the activating light is 405 nm) is even more preferably 45% or more, and particularly preferably 50% or more.
  • the total number of particles having a particle diameter in the range of 85 to 535 nm preferably accounts for 40% or more of the total number of primary particles constituting the inorganic filler (B), more preferably 60% or more, and even more preferably 80% or more.
  • a more preferred particle diameter range is 121 to 400 nm, and an even more preferred particle diameter range is 218 to 375 nm.
  • the total number of particles having a particle diameter in the range of 218 to 375 nm accounts for 80% or more of the total number of primary particles constituting the inorganic filler (B).
  • the refractive index of the inorganic filler and the polymerizable monomer component used in dentistry it is preferable to adopt a combination of inorganic filler (B) and polymerizable monomer component (A) that satisfies the following conditions 2 to 4.
  • the inorganic powder particles constituting the inorganic filler (B) when an inorganic powder particle consisting of an aggregate of a single type of inorganic particles having a refractive index at 25°C to the (sodium) D line: n (D)F in the range of 1.500 to 1.550 is defined as a specific inorganic powder particle (b1), and an inorganic powder particle consisting of an aggregate of a single type of inorganic particles having a refractive index outside the above range is defined as a non-specific inorganic powder particle (b2), the non-composite inorganic filler (B1) and the composite inorganic filler (B2) are respectively (1) Consisting of a single type of specific inorganic powder or particle (b1), (2) It is composed of multiple types of specific inorganic powder and granules (b1), and at least one of the multiple types of specific inorganic powder and granules (b1) accounts for 10 mass% or more of the total mass of the non-
  • n (D)M The refractive index of the polymerizable monomer component (A) at 25° C. with respect to the D line: n (D)M is in the range of 1.490 to 1.550.
  • Condition 4 When the refractive index at 25°C of at least one specific inorganic powder or particle (b1) that accounts for 10 mass% or more of the total mass of each of the non-composite inorganic filler (B1) and the composite inorganic filler (B2) is n (D)F , and the refractive index that has the largest difference from n( D )M is n(D)Fh , the absolute value of the difference between n (D)Fh and n (D)M :
  • is 0.035 or less.
  • the refractive index at 25°C of the inorganic filler (B) (non-composite inorganic filler (B1) and composite inorganic filler (B2)) to the D line: n (D)F , and the refractive index at 25°C of the polymerizable monomer component to the D line: n (D)M can be measured as follows.
  • the refractive index of the polymerizable monomer component: n (D)M can be measured using an Abbe refractometer (for example, Digital Abbe refractometer DR-A1-PLUS, manufactured by Atago Co., Ltd.) by placing the prepared monomer composition on a prism, looking into the sample through an eyepiece, and reading the value on the display when the boundary line and the cross line intersect (this value is the refractive index).
  • an Abbe refractometer for example, Digital Abbe refractometer DR-A1-PLUS, manufactured by Atago Co., Ltd.
  • the refractive index of the inorganic powder particles constituting the inorganic filler: n (D)F can be determined by mixing toluene or ethanol with bromonaphthalene to prepare solutions with refractive indices varying in increments of 0.001, mixing each inorganic powder particle with each solution with a different refractive index, shaking the mixture, and determining the refractive index of the solution that appears most transparent as the refractive index of that inorganic powder particle.
  • the curable composition for stereolithography of the present disclosure must have a transmittance of 1 to 50% for specific activating light measured on a 0.5 mm thick sample. This transmittance serves as an indicator of the depth of cure. If the transmittance is lower than the lower limit of 1%, sufficient cure depth cannot be achieved, making stereolithography difficult. Even if stereolithography is possible, cracks are likely to occur in the model. Furthermore, in systems containing 40 parts by mass or more of inorganic filler (B) per 100 parts by mass of polymerizable monomer component (A) and containing a polymerization initiator in an amount sufficient for stereolithography, it is difficult to achieve a transmittance significantly exceeding the upper limit of 50%.
  • the transmittance is preferably 2 to 30%, and more preferably 5 to 20%.
  • the curable composition for stereolithography disclosed herein contains a photopolymerization initiator, there are concerns that curing may progress due to light irradiation during measurement.
  • a transmittance measurement method using a color difference meter as described below, it is possible to measure the transmittance of specific activating light before curing progresses.
  • the transmittance of the disclosed photocurable composition for stereolithography to activating light can be measured as follows. First, a 0.5 mm thick measurement sample is prepared by filling a resin mold (25 mm x 25 mm x 0.5 mm thick) with the disclosed photocurable resin composition, pressing the top and bottom surfaces with glass slides, reducing the thickness to 0.5 mm, and then removing the glass slide.
  • a resin mold 25 mm x 25 mm x 0.5 mm thick
  • this measurement sample is placed in a color difference meter (e.g., the SE7700 spectrophotometer manufactured by Nippon Denshoku Industries Co., Ltd.), and the transmittance of specific activating light (e.g., 405 nm wavelength light or 385 nm wavelength light) is measured by transmittance measurement using measurement light from a halogen lamp (measurement wavelength: 380-780 nm).
  • a color difference meter e.g., the SE7700 spectrophotometer manufactured by Nippon Denshoku Industries Co., Ltd.
  • the transmittance of specific activating light e.g., 405 nm wavelength light or 385 nm wavelength light
  • the above transmittance tends to be higher as the light transmittance of the resin (R) constituting the polymerizable monomer component (A), inorganic filler (B), and organic-inorganic composite filler (E) itself increases.
  • the transmittance also tends to be higher as the difference between the refractive index of the inorganic filler (B) to the specific activating light and the refractive index of the polymerizable monomer component (A) to the specific activating light, the difference between the refractive index of the resin (R) to the specific activating light and the refractive index of the polymerizable monomer component (A) to the specific activating light, and the difference between the refractive index of the inorganic filler (B) to the specific activating light and the refractive index of the resin (R) to the specific activating light are smaller.
  • the blending ratio affects the transmittance.
  • the transmittance of polymerizable monomer components and resins is significantly higher than 5%, so as long as the amount of inorganic filler blended is within the specified range, using a translucent inorganic filler and reducing the refractive index difference makes it possible to not only achieve a transmittance of 1% or more, but also 3% or 5% or more.
  • the polymerizable monomer component (A), inorganic filler (B), and resin (R) satisfy the following condition 5.
  • Condition 5 The refractive index of at least one specific inorganic powder or particle (b1) at 25°C to specific activating light: n (AL)F , the refractive index of the polymerizable monomer component (A) at 25°C to specific activating light: n(AL) M , and the refractive index of the resin (R) at 25°C to specific activating light: n (AL)R satisfy the following (i) to (iii): -0.015 ⁇ (n (AL)F -n (AL)M ) ⁇ 0.025 (i) -0.015 ⁇ (n (AL)R -n (AL)M ) ⁇ 0.030 (ii) -0.020 ⁇ (n (AL)F -n (AL)R ) ⁇ 0.020 (iii) All the conditions shown in are satisfied.
  • Condition 5 is the following (ia) to (iiia): -0.012 ⁇ (n (AL)F -n (AL)M ) ⁇ 0.022 (ia) -0.010 ⁇ (n (AL)R -n (AL)M ) ⁇ 0.022 (iia) -0.020 ⁇ (n (AL)F -n (AL)R ) ⁇ 0.017 (iiia) It is preferable that all of the conditions shown in (1) and (2) are satisfied.
  • the disclosed method for producing a curable composition for stereolithography is characterized by using a combination of polymerizable monomer component (A), inorganic filler (B), photopolymerization initiator (C), activated light absorber (D), and organic-inorganic composite filler (E) that satisfies the above conditions, and by employing this production method, the disclosed curable composition for stereolithography can be easily produced.
  • the method for producing a curable composition for stereolithography according to the present disclosure is a method for producing a curable composition for stereolithography according to the present disclosure, which comprises the steps of:
  • the method includes a mixing step of mixing a polymerizable monomer component (A), a non-composite inorganic filler (B1), an organic-inorganic composite filler (E), a photopolymerization initiator (C), and an activated light absorber (D),
  • the polymerizable monomer component (A), the non-composite inorganic filler (B1), and the organic-inorganic composite filler (E) satisfy all of the above-mentioned conditions 1 to 5, and when a composition consisting only of the polymerizable monomer component (A), the non-composite inorganic filler (B1), and the organic-inorganic composite filler (E) is used as a base composition, in which the compositional ratio of these components is the same as that of the curable composition for stereolith
  • the components are preferably mixed using a stirrer at room temperature in the dark, under light that activates the photopolymerization initiator, for example, under red light, until uniform, and after mixing, it is preferable to perform a degassing treatment.
  • the method for producing a three-dimensional stereolithography object according to the present disclosure is a method for producing a three-dimensional object by liquid vat photopolymerization, which includes the above-described molding step, washing step, and secondary curing step, and is characterized in that the curable composition for stereolithography according to the present disclosure is used as the liquid photocurable composition supplied to the tank of the liquid vat photopolymerization device.
  • the method for producing a three-dimensional stereolithography object according to the present disclosure uses the curable composition for stereolithography according to the present disclosure, it is possible to produce a three-dimensional stereolithography object that has high mechanical strength and is free of cracks on its actual surface.
  • the molding step includes: a first step of irradiating a predetermined position of a liquid photocurable composition held in a tank with activating light based on two-dimensional shape data at the height of the initial ranking order, thereby curing the composition, thereby forming a modeling layer having a shape corresponding to the two-dimensional shape data, and using the modeling layer as a bonding layer; a second step of supplying a liquid photocurable composition directly above or directly below the bonded layer in the tank by moving the bonded layer up or down; a third step of applying activation light to a predetermined position of the liquid photocurable composition supplied just above or just below the bonded layer based on the two-dimensional shape data at the next highest level in the ranking order in the previous step, thereby curing the composition, thereby forming a new modeling layer having a shape corresponding to the two-dimensional shape data, and bonding the new modeling layer to the bonded layer, thereby obtaining
  • the new bonded layer is used as the bonded layer in the third step, and the cycle consisting of the third step and the fourth step is repeated, and in the final third step, a new modeling layer is formed based on the two-dimensional shape data at the height of the final ranking order to obtain a laminate.
  • liquid vat photopolymerization method which includes a molding process, can be suitably carried out using commercially available liquid vat photopolymerization devices known as 3D printers.
  • the resulting laminate is washed with an organic solvent (a washing step is performed), and then the laminate is subjected to additional irradiation with activating light, heat treatment, or both for secondary curing (a secondary curing step is performed).
  • Organic solvents used in the cleaning process include alcohol-based solvents such as ethanol, methanol, and isopropyl alcohol; ketone-based solvents such as acetone and methyl ethyl ketone; ether-based solvents such as diethyl ether, diisopropyl ether, tripropylene glycol monomethyl ether, and tetrahydrofuran; amide-based solvents such as N-methylpyrrolidone and dimethylacetamide; and halogen-based solvents such as methylene chloride and chloroform.
  • alcohol-based solvents and ether-based solvents are preferred due to their high cleaning efficiency, and alcohol-based solvents are more preferred due to their low environmental impact.
  • the wavelength of the additional activating light irradiation in the secondary curing step is not particularly limited, as long as it is a wavelength that can be absorbed by the photopolymerization initiator remaining in the laminate to generate radicals.
  • the irradiation intensity of the additional activating light irradiation is preferably 5 mW/cm 2 or more, more preferably 10 mW/cm 2 or more, and even more preferably 30 mW/cm 2 or more , so that the photopolymerization initiator remaining in the laminate generates a sufficient amount of radicals.
  • the irradiation time 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.
  • the irradiation intensity during the additional activating light irradiation is too high, the molded object may be overheated, causing cracks in the molded object. Therefore, the irradiation intensity is preferably 10,000 mW/cm 2 or less.
  • thermal polymerization initiator when blended into the curable composition for stereolithography disclosed herein, this can be used to carry out secondary curing by heating.
  • the heating temperature in this case is preferably 45 to 120°C, more preferably 50 to 90°C, and even more preferably 55 to 80°C.
  • the disclosed method for manufacturing dental restorations is characterized by manufacturing dental restorations such as inlays, onlays, crowns, and dentures using the disclosed method for manufacturing three-dimensional optically shaped objects.
  • CAD data designed based on digital data obtained by scanning the intraoral shape of an individual patient or an intraoral model created for each individual patient can be used as three-dimensional shape data indicating the shape of the dental restoration (three-dimensional object) used in the molding process.
  • the disclosed method for manufacturing dental restorations makes it possible to manufacture dental restorations that have high mechanical strength and are free of cracks on their actual surfaces.
  • UDMA urethane dimethacrylate
  • 3G triethylene glycol dimethacrylate
  • D-2.6E bisphenol A ethylene glycol (EO) adduct dimethacrylate (average number of EOs added: 2.6)
  • ACMO Acryloylmorpholine 8FHD: Octafluorooctanediol dimethacrylate
  • the monomer compositions used were monomer compositions A1 to A15 prepared by mixing the above monomer compounds according to the compositions shown in Table 1.
  • the values in parentheses in Table 1 indicate the content (mass%) of each monomer compound.
  • the refractive index of each monomer composition with respect to the D-line at 25°C: n (D)M and the refractive index of each monomer composition with respect to activation light having a wavelength of 405 nm at 25°C: n (AL)M were measured for each sample by placing the sample on the prism of a digital Abbe refractometer (DR-M2, manufactured by Atago Co., Ltd.), using an interference filter that selectively transmits the measurement light (D-line or light with a wavelength of 405 nm), looking into the sample through an eyepiece, and reading the value on the display when the boundary line and the cross line intersect.
  • D-M2 digital Abbe refractometer
  • Inorganic filler (B) The inorganic powders and granules shown below were used as they were or in combination with a plurality of types thereof to form inorganic fillers B-1 to B-8 so as to obtain the compositions shown in Table 2.
  • SZ-3 Spherical silica-zirconia (surface treated with ⁇ -methacryloyloxypropyltri
  • the refractive indices n (D)F and n (AL)F of each inorganic powder and granule were measured by the following method. Specifically, ethanol or toluene was mixed with bromonaphthalene to prepare solutions with refractive indices varying in increments of 0.001. Then, each inorganic powder and granule was mixed with each solution with a different refractive index to prepare an inorganic powder and granule mixed solution, and the solution in which the mixed solution was observed to be the most transparent was measured in the same manner as in the measurement of the refractive index of the monomer composition, and this refractive index was designated as the refractive index n (D)F of the inorganic powder and granule.
  • the mixed solution was irradiated with activating light (light with a wavelength of 405 nm), and the solution in which the activating light was observed most clearly was measured in the same manner as in the measurement of the refractive index of the monomer composition, and this refractive index was designated as the refractive index n (AL)F of the inorganic powder and granule.
  • the content of particles having a particle diameter of 0.05 to 5.0 ⁇ m relative to the total particles constituting each inorganic filler was measured from the particle size distribution determined by microscopy using a scanning microscope (referred to as the "specific particle content” in Table 2). Furthermore, for each inorganic filler, the content of particles having a (primary) particle diameter within a specific range of particle diameter parameter ⁇ (referred to as the " ⁇ -sufficient particle content” in Table 2) was determined from the particle size distribution determined by microscopy using a scanning microscope.
  • the content of particles having a particle diameter parameter ⁇ in the range of 0.7 to 4.0: R1 (%), the content of particles having a particle diameter parameter ⁇ in the range of 1.0 to 3.0: R2 (%), and the content of particles having a particle diameter parameter ⁇ in the range of 1.8 to 2.8: R3 (%) were determined.
  • the results are also shown in Table 2.
  • the particle size distribution was determined by measuring the number of all particles (50 or more) observed within a unit field of view in a scanning electron microscope photograph of each inorganic filler: n (number of particles), and the primary particle diameter (maximum diameter): Xi (nm) of all particles.
  • Organic-inorganic composite fillers CF1 to CF9 were prepared in the same manner as in Example 1 of Patent Document 4 (WO 2013/039169), except that the inorganic powder and granules shown in Table 3 below and the monomer composition having the composition shown in Table 3 below were used as the polymerizable monomer components serving as raw materials for the composite inorganic filler (B2) and resin (R) constituting the organic-inorganic composite filler.
  • the numbers in parentheses in Table 3 below indicate the content (% by mass) of each monomer compound.
  • the cured product of the monomer composition becomes the resin (R), which covers the surfaces of the inorganic primary particles that become the composite inorganic filler (B2) and bonds the inorganic primary particles to each other to form a composite.
  • the refractive index n (AL)R in Table 3 is a value measured by placing a 0.1 mm thick cured product of the monomer composition on the prism of a digital Abbe refractometer (DR-M2, manufactured by Atago Co., Ltd.), using an interference filter that selectively transmits measurement light (light with a wavelength of 405 nm), looking into the sample through an eyepiece, and reading the value on the display when the boundary line and the intersection of the cross lines are aligned.
  • D-M2 digital Abbe refractometer
  • Photopolymerization initiator BAPO: phenylbis(2,4,6-trimethylbenzoyl)phosphine oxide (generates radicals when irradiated with activation light at a wavelength of 405 nm)
  • TPO 2,4,6-trimethylbenzoyl-diphenylphosphine oxide
  • CQ camphorquinone DMBE: dimethyl p-ethoxybenzoate
  • Activated Light Absorber SS3 2-(3-tert-butyl-2-hydroxy-5-methylphenyl)-5-chloro-2H-benzotriazole
  • Coloring substance Titanium oxide (average primary particle diameter: 200 ⁇ m)
  • the curable composition for stereolithography disclosed herein belongs to the category of previously proposed curable compositions.
  • the previously proposed curable compositions have the advantage of enabling the production of three-dimensional stereolithography objects with excellent mechanical strength and shape accuracy while minimizing the risk of decreased fluidity and sedimentation of inorganic fillers and preventing the occurrence of cracks on the surface. Therefore, this point will be explained first with reference to the following Reference Examples and Comparative Examples.
  • ⁇ Reference Example 1> Preparation of base composition for Sc evaluation and curable composition for stereolithography To 100 parts by mass of a polymerizable monomer component consisting of monomer composition A1 (UDMA: 50 parts by mass, 3G: 20 parts by mass, D-2.6E: 30 parts by mass), 150 parts by mass of B-1 as a non-composite inorganic filler (B1) was added, and the mixture was stirred and mixed until homogeneous, followed by degassing to prepare a base composition for Sc evaluation.
  • a polymerizable monomer component consisting of monomer composition A1 (UDMA: 50 parts by mass, 3G: 20 parts by mass, D-2.6E: 30 parts by mass)
  • B-1 a non-composite inorganic filler
  • a raw material base composition was prepared in the same manner, to which was added 1.4 parts by mass of a photopolymerization initiator consisting of BAPO, 0.7 parts by mass of an activated light absorber consisting of SS3, and a total of 0.2 parts by mass of a polymerization inhibitor consisting of 0.1 parts by mass of HQME and 0.1 parts by mass of BHT (all blend amounts are relative to 100 parts by mass of polymerizable monomer components).
  • the mixture was stirred and mixed under red light until uniform, and then degassed to prepare a liquid curable composition for stereolithography.
  • the stereolithography curable resin composition obtained in (1) above was filled into a PTFE resin mold (25 mm x 25 mm x 0.5 mm thick). The top and bottom surfaces were pressed with glass slides to adjust the thickness of the composition to 0.5 mm, and then the glass slides were removed to obtain a resin composition with a thickness of 0.5 mm.
  • the transmittance of this resin composition at a wavelength of 405 nm was measured using a color difference meter (Spectrophotometer SE7700, manufactured by Nippon Denshoku Industries Co., Ltd.). The result was a transmittance of 5.3%.
  • the stereolithography curable composition obtained in (1) above was supplied to the resin tray (tank) of a 3D printer (DWS, DW029D; wavelength: 405 nm, irradiation intensity: 83 mW), and a molding process was performed using 10 mm x 10 mm x 25 mm rectangular parallelepiped stereolithography data (hereinafter abbreviated as "stl data").
  • stl data 10 mm x 10 mm x 25 mm rectangular parallelepiped stereolithography data
  • the obtained molded body was immersed in a plastic container filled with ethanol for 15 minutes, gently shaken, and washed, then dried, and further irradiated with additional light (secondary curing) using a UV CURING UNIT UVIS-2 (DWS) for 30 minutes to produce a three-dimensional stereolithography object.
  • DWS UV CURING UNIT UVIS-2
  • the surface of the evaluation sample was observed with an optical microscope (50x magnification), and the evaluation sample was also coated with platinum to a thickness of 5 nm and then observed with a scanning microscope (1000x magnification).
  • the number and width of cracks observed on one surface of the evaluation sample, measuring 10 mm x 25 mm, were confirmed and evaluated according to the following evaluation criteria. As a result, the crack evaluation result was "A1".
  • A1 The number of cracks observed on the surface of the cured body was 5 or less, and the width of each crack was 10 ⁇ m or less, which is within the acceptable range.
  • A2 The number of cracks observed on the surface of the cured body was 10 or less, and the width of each crack was 10 ⁇ m or less, which is within the acceptable range.
  • A3 The number of cracks observed on the surface of the cured body was 20 or less, and the width of each crack was 10 ⁇ m or less, which is within the acceptable range.
  • B The number of cracks observed on the surface of the cured body was 20 or less, and the crack width was 10 to 40 ⁇ m.
  • C 20 or more cracks with widths of 10 to 40 ⁇ m are observed on the surface of the cured body.
  • D A large number of cracks with widths of 40 ⁇ m or more are observed on the surface of the cured body.
  • a curable composition for stereolithography was prepared according to the method described in Example 1 of Patent Document 3. Specifically, the polymerizable monomer component (A) and inorganic filler (B) shown in Table 5 were used in the blending ratios shown in Table 5, and 3.0 parts by mass of a polymerization initiator consisting of TPO and 0.05 parts by mass of a polymerization inhibitor consisting of BHT (all blending amounts are relative to 100 parts by mass of the polymerizable monomer component) were added to prepare a curable composition for stereolithography. A three-dimensional object was then manufactured and evaluated using the resulting curable composition for stereolithography in the same manner as in Reference Example 1.
  • a base composition for Sc evaluation and an uncured composition (for transmittance evaluation) were also prepared in the same manner as in Reference Example 1, and each composition was evaluated in the same manner as in Reference Example 1.
  • the evaluation results are shown in Table 7.
  • An optical microscope image (magnification: 50x) taken during crack evaluation of Reference Comparative Example 9 (Evaluation C) is shown in Figure 4.
  • the curable compositions for stereolithography of Reference Examples 1 to 14 had a small light scattering index Sc and a high activation light transmittance, resulting in high modeling accuracy and reduced cracking.
  • the stereolithography curable compositions of Reference Comparative Examples 1 to 3 had a high light scattering index Sc and a low activation light transmittance, resulting in low modeling accuracy and cracking. Furthermore, the stereolithography curable compositions of Reference Comparative Examples 4 to 7 had a low light scattering index Sc but a low activation light transmittance, resulting in cracking. The stereolithography curable composition of Reference Comparative Example 8 had a high light scattering index Sc, resulting in low modeling accuracy and cracking.
  • the stereolithography curable composition of Reference Comparative Example 9 was prepared in accordance with the method described in Patent Document 3, and had a low activation light transmittance, resulting in cracking.
  • Example 1 Preparation of base composition for Sc evaluation and photocurable composition
  • the polymerizable monomer component (A) consisting of the monomer composition A7 (UDMA: 35 parts by mass, 3G: 27 parts by mass, D-2.6E: 38 parts by mass)
  • 60 parts by mass of B-1 as a non-composite inorganic filler (B1) and 90 parts by mass of CF1 as an organic-inorganic composite filler (E) were added, and the mixture was stirred and mixed until uniform, followed by degassing to prepare a base composition for Sc evaluation.
  • a raw material base composition was prepared in the same manner, to which was added 1.4 parts by mass of a photopolymerization initiator consisting of BAPO, 0.7 parts by mass of an activated light absorber consisting of SS3, and a total of 0.2 parts by mass of a polymerization inhibitor consisting of 0.1 parts by mass of HQME and 0.1 parts by mass of BHT (all blend amounts are relative to 100 parts by mass of polymerizable monomer components).
  • the mixture was stirred and mixed under red light until uniform, and then degassed to prepare a liquid curable composition for stereolithography.
  • the light-scattering index Sc and activation light transmittance of the obtained base composition for Sc evaluation and curable composition for stereolithography were measured in the same manner as in Reference Example 1. As a result, the light-scattering index Sc was 0.5%, and the activation light transmittance was 6.9%.
  • stereolithography curable composition of Example 1 500 g was supplied to the resin tray (tank) of a 3D printer (DWS, DW029D; wavelength: 405 nm, irradiation intensity: 83 mW), and a molding process was carried out using stereolithography data (stl data) of a rectangular parallelepiped shape of 150 mm x 150 mm x 200 mm, and a molded body (laminate) having a laminated structure (composed of a cured product of the stereolithography curable composition) was produced.
  • stereolithography data stereolithography data
  • the obtained molded body was immersed in a plastic container filled with ethanol for 15 minutes, gently shaken to perform a washing process, then dried, and further subjected to additional light irradiation (secondary curing) for 30 minutes using a UV CURING UNIT UVIS-2 (DWS) to produce a three-dimensional stereolithography object.
  • additional light irradiation secondary curing
  • DWS UV CURING UNIT UVIS-2
  • the resulting 150mm x 150mm x 200mm rectangular 3D photofabricated object was observed visually and with an optical microscope (50x magnification) to evaluate whether there were any defects in the rectangular shape. As a result, there were no defects either visually or with an optical microscope (50x magnification), confirming that the object had high fluidity (Evaluation result: A).
  • Examples 2 to 20 and Comparative Examples 1 to 6> The base composition for Sc evaluation and the curable composition for stereolithography were prepared in the same manner as in Example 1, except that the components and amounts used when preparing the base composition for Sc evaluation and the curable composition for stereolithography in Example 1 were changed as shown in Tables 8 and 9. Thereafter, the resulting compositions were evaluated in the same manner as in Example 1, and three-dimensional stereolithography objects were produced and evaluated using the resulting curable compositions for stereolithography in the same manner as in Example 1. The evaluation results are shown in Tables 10 and 11.
  • the curable compositions for stereolithography of Examples 1 to 20 had a small light scattering index Sc and a high activation light transmittance, resulting in high modeling accuracy and reduced cracking.
  • the photopolymerization curable composition of Comparative Example 1 had a large difference in refractive index for 405 nm light between the composite inorganic filler (B2) and resin (R) constituting the organic-inorganic composite filler (E), resulting in low transmittance for 405 nm light, and therefore increased cracking.
  • the photopolymerization curable composition of Comparative Example 2 had a large difference in refractive index for 405 nm light between the polymerizable monomer component (A) and composite inorganic filler (B2) constituting the organic-inorganic composite filler (E), resulting in low transmittance for 405 nm light, and therefore increased cracking.
  • the photopolymerization curable composition of Comparative Example 3 had a large difference in refractive index for 405 nm light between the polymerizable monomer component (A) and resin (R) constituting the organic-inorganic composite filler (E), resulting in low transmittance for 405 nm light, and therefore increased cracking.
  • the curable compositions for stereolithography in Comparative Examples 4 to 6 had a large difference in refractive index for 405 nm light between the polymerizable monomer component (A) and the composite inorganic filler (B2) and resin (R) that make up the organic-inorganic composite filler (E), resulting in low transmittance for 405 nm light and increased cracking.
  • Examples 21 to 32 and Comparative Examples 7 to 10> In Examples 1, 14, and 18, and Comparative Example 1, three-dimensional stereolithography objects were manufactured and evaluated in the same manner as in Examples 1, 14, and 18, and Comparative Example 1, except that the 3D printer used to manufacture the three-dimensional stereolithography objects was changed as shown in Tables 12 and 13. The evaluation results are shown in Tables 12 and 13. Tables 12 and 13 also show the evaluation results for Examples 1, 14, and 18, and Comparative Example 1.
  • the stereolithography curable composition used in Examples 21 to 24 has the same composition as the stereolithography curable composition used in Example 1.
  • the stereolithography curable composition used in Examples 25 to 29 has the same composition as the stereolithography curable composition used in Example 14.
  • the stereolithography curable composition used in Examples 29 to 32 has the same composition as the stereolithography curable composition used in Example 18.
  • the stereolithography curable composition used in Comparative Examples 7 to 10 has the same composition as the stereolithography curable composition used in Comparative Example 1.
  • 3DP1 to 3DP5 in Tables 12 and 13 refer to the following 3D printers, respectively.
  • ⁇ 3DP2 SEGA 3D (DLP method, wavelength: 405 nm), manufactured by 3BFAB
  • ⁇ 3DP4 Manufactured by Phrozen
  • Smapri Sonic 8K (LCD method, wavelength: 405 nm)

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Abstract

L'invention propose : une composition durcissable pour stéréolithographie tridimensionnelle, qui contient 100 parties en masse d'un composant monomère polymérisable (A), 40 à 400 parties en masse d'une charge minérale (B), 0,01 à 5 parties en masse d'un photoinitiateur (C), et 0,01 à 2,5 parties en masse d'un absorbeur de lumière d'activation (D), et dans laquelle 10 à 90 % en masse de la charge minérale (B) est contenue en tant que charge composite organique-minérale (E), la valeur de l'indice de diffusion Sc servant d'indice de la proportion de lumière diffusée latéralement lorsqu'elle est irradiée avec une lumière d'activation est inférieure ou égale à 10 %, et le taux de transmission pour la lumière d'activation dans un état avant qu'il soit optiquement durci est de 1 à 50 % ; et un procédé de production de la composition durcissable pour stéréolithographie tridimensionnelle. La présente invention propose également un procédé de production d'un produit stéréolithographique tridimensionnel et un procédé de production d'un article de restauration dentaire, pour lesquels ladite composition durcissable pour stéréolithographie tridimensionnelle est utilisée.
PCT/JP2024/044729 2024-01-31 2024-12-18 Composition durcissable pour stéréolithographie tridimensionnelle, son procédé de production, procédé de production d'un produit stéréolithographique tridimensionnel et procédé de production d'un article de restauration dentaire Pending WO2025164130A1 (fr)

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WO2013039169A1 (fr) * 2011-09-15 2013-03-21 株式会社トクヤマデンタル Charge composite organique-inorganique et procédé pour sa production
JP2021165375A (ja) * 2020-04-07 2021-10-14 キヤノン株式会社 立体造形用の光硬化性樹脂組成物
WO2023008233A1 (fr) * 2021-07-30 2023-02-02 株式会社トクヤマデンタル Procédé de fabrication d'objets moulés tridimensionnels
WO2023210328A1 (fr) * 2022-04-25 2023-11-02 株式会社トクヤマデンタル Composition de résine photodurcissable pour photoformage tridimensionnel
WO2024166632A1 (fr) * 2023-02-09 2024-08-15 株式会社トクヤマデンタル Composition durcissable pour stéréolithographie tridimensionnelle, son procédé de production, procédé de production d'un modèle stéréolithographique tridimensionnel et procédé de production d'une restauration dentaire

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WO2013039169A1 (fr) * 2011-09-15 2013-03-21 株式会社トクヤマデンタル Charge composite organique-inorganique et procédé pour sa production
JP2021165375A (ja) * 2020-04-07 2021-10-14 キヤノン株式会社 立体造形用の光硬化性樹脂組成物
WO2023008233A1 (fr) * 2021-07-30 2023-02-02 株式会社トクヤマデンタル Procédé de fabrication d'objets moulés tridimensionnels
WO2023210328A1 (fr) * 2022-04-25 2023-11-02 株式会社トクヤマデンタル Composition de résine photodurcissable pour photoformage tridimensionnel
WO2024166632A1 (fr) * 2023-02-09 2024-08-15 株式会社トクヤマデンタル Composition durcissable pour stéréolithographie tridimensionnelle, son procédé de production, procédé de production d'un modèle stéréolithographique tridimensionnel et procédé de production d'une restauration dentaire

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