Process for manufacturing surface-modified 3D articles by additive manufacturing, 3D articles having modified surfaces, and their use.

Abstract

A process for producing a surface-modified three-dimensional article, comprising the steps of providing a radiation-curable composition, building up the three-dimensional article by radiation-curing the radiation-curable composition, preferably by using a stereolithography or digital light processing unit, partially removing the radiation-curable composition adhering to the surface of the three-dimensional article, treating with particles only the part of the surface of the three-dimensional article to which the radiation-curable composition adheres, and applying an additional curing step to the three-dimensional article, preferably by applying heat and / or radiation. Three-dimensional articles obtainable by such a process, and kits of parts comprising such three-dimensional articles.

Description

[Technical Field]

[0001] This invention relates to a process for manufacturing surface-modified articles by additive manufacturing, articles having modified surfaces, and the use thereof.

[0002] This process can be used to manufacture dental or orthodontic restorations, in particular, that can be more easily fixed to the tooth surface. [Background technology]

[0003] In various technological fields, physical objects or mechanical workpieces are increasingly being manufactured using additive manufacturing processes.

[0004] Such additive manufacturing processes typically allow for the construction of an object into a desired individual shape by continuously adding material to create its form, for example, by the layer-by-layer curing of radiation-curable compositions. Stereolithography (SLA) and digital light processing (DLP) are examples of techniques in which objects are built up layer by layer. These processes are often referred to as "3D printing."

[0005] After the radiation curing process is complete, the 3D printed object is removed from the printing vat, resulting in the presence of uncured printing resin on the surface of the resulting 3D printed object.

[0006] The uncured resin must be removed afterward. Otherwise, the desired surface accuracy cannot be obtained. Removal of the uncured resin can be achieved in various ways by applying a cleaning process.

[0007] For example, International Publication No. 2019 / 023120 (A1) (3M) describes a method of fabricating a physical object by additive manufacturing, the method including: a) providing a curable primary material and building up the object; and c) moving the object to generate a mass inertial force on the excess material, thereby cleaning the object from the excess material.

[0008] International Publication No. 2018 / 222395 (A1) (3M) describes the use of a cleaning composition for removing uncured printing resin from a 3D printed article, the cleaning composition including, either alone or in combination, the following components: dibasic esters of carboxylic acids, tribasic esters of carboxylic acids.

[0009] A system that can be used to clean a 3D printed object is described in International Publication No. 2019 / 111208 (A1) (3M). Typically, a post-curing process is applied to ensure that the 3D printed article obtained after the cleaning process is in its fully cured state and has the desired mechanical properties.

[0010] Post-curing is typically performed by applying radiation to the 3D printed article, for example, by using a radiation curing unit.

[0011] The additive manufacturing process can also be used in the dental industry to manufacture so-called dental composite crowns, i.e., crowns made by radiation curing of layers of a radiation curable composition.

[0012] For example, International Publication No. 2018 / 231583 (A1) (3M) relates to a curable composition including a resin matrix, a filler matrix, and an initiator system that can be used for 3D printing of dental composite crowns.

[0013] The fixation or cementation of dental composite crowns is not straightforward and typically requires a series of steps, including the use of appropriate dental cement.

[0014] To enhance retention or fixation, the inner surface of a dental composite crown is typically roughened, for example, by sandblasting.

[0015] Sandblasting the inner surface of a dental composite crown typically provides mechanical retention to the dental cement. In addition to chemical bonding, mechanical retention is considered a crucial aspect of achieving sufficient bonding strength between the dental composite crown and the tooth surface.

[0016] Therefore, a higher surface roughness, a surface with a greater ability to chemically bond with cement, and / or a more robust cementation process for 3D-printed dental composite crowns may be desirable.

[0017] A process for smoothing surfaces manufactured using stereolithography is also provided.

[0018] U.S. Patent No. 5,234,636 (Hull et al.) describes a method for coating a stereolithography component with a material that can become less viscous when heated, thereby smoothing over characteristic surface discontinuities having alternating recesses and peaks, and heating the material to allow the material to flow into the recesses of the surface.

[0019] International Publication No. 2019 / 102304(A1)(3M) describes a method for fabricating a physical object by additive manufacturing, comprising the steps of providing a photo-solidifiable primary material, building up an object, coating at least a portion of the object with a fluid coating, and irradiating the coated object with light.

[0020] International Publication No. 2019 / 190902(A1) (Carbon Inc.) describes a method for producing a functionally coated object, the method comprising: producing a raw intermediate object by stereolithography from a double-cured polymerizable resin containing an uncured polymerizable material; coating at least one surface portion of the object with a particulate material; and heating the object, wherein the coating and / or heating steps are performed under conditions in which the uncured polymerizable material penetrates or seeps out of the surface of the object, the uncured polymerizable material polymerizes in contact with the particulate material, and bonds the particulate material to the surface of the object. [Overview of the Initiative]

[0021] In general, there is a need for processes that enable easy surface modification of three-dimensional articles, particularly three-dimensional articles obtained or obtainable using additive manufacturing processes.

[0022] More precisely, there is a need for a process that enables the manufacture of three-dimensional articles, particularly three-dimensional articles having the shape of dental or orthodontic articles that can be more easily fixed to a surface, such as the surface of a tooth.

[0023] Ideally, it should be possible to fix a three-dimensional article obtained or obtainable by such a process to a surface using dental cement.

[0024] One or more of the above objectives are addressed by the present invention.

[0025] In one embodiment, the present invention is characterized by a process for manufacturing a surface-modified three-dimensional article, the process being A step of providing a radiation-curable composition, A process of building up a three-dimensional article by radiation-curing a radiation-curable composition layer by layer, preferably by using stereolithography or a digital light processing unit. A step of partially removing a radiation-curable composition adhering to the surface of a three-dimensional article, A step of treating at least a portion of the surface of a three-dimensional article to which a radiation-curable composition is attached with particles, The process includes applying an additional curing step to a three-dimensional article, preferably by applying heat and / or radiation.

[0026] In another embodiment, the present invention relates to a three-dimensional article obtained or obtainable by such a process.

[0027] Further embodiments of the present invention aim at a kit of parts, including a three-dimensional article and dental cement, which can be used to fix the three-dimensional article to a tooth surface.

[0028] The present invention also relates to a kit of parts comprising a radiation-curable composition, particles, and an additive manufacturing apparatus, the radiation-curable composition, particles, and additive manufacturing apparatus as described herein.

[0029] Unless otherwise defined, the following terms have the meanings set forth below in this specification.

[0030] The terms "compound" or "component" refer to a chemical substance having a specific molecular identity, or a chemical substance made from such a substance, for example, a mixture of polymeric substances.

[0031] A "hardenable, curable, or polymerizable component" is any component that can be cured or solidified by radiation-induced polymerization in the presence of a photoinitiator. A hardenable component may contain one, two, three, or more polymerizable groups. Typical examples of polymerizable groups include unsaturated carbon groups such as vinyl groups present in (methyl)acrylate groups.

[0032] As used herein, "(meth)acrylic" is an abbreviation for "acrylic" and / or "methacrylic". For example, "(meth)acrylicoxy" group is an abbreviation for either an acrylicoxy group (i.e., CH2=CH-C(O)-O-) and / or a methacrylicoxy group (i.e., CH2=C(CH3)-C(O)-O-).

[0033] As used herein, “solidification” or “curing” of a composition is interchangeable and refers to polymerization and / or crosslinking reactions, including, for example, photopolymerization and chemical polymerization techniques (e.g., ionic or chemical reactions that form radicals effective for polymerizing ethylenically unsaturated compounds), in which one or more materials contained in the composition are involved.

[0034] A "photoinitiator" is a substance that can initiate or start the curing process of a solidifying composition in the presence of radiation, particularly light (wavelengths of 300 nm to 700 nm).

[0035] "Dental articles" specifically refer to articles used in the manufacture of dental restorations.

[0036] "Dental restorations" refer to dental items used to repair missing tooth structures.

[0037] Examples of dental restorations include crowns, bridges, inlays, onlays, veneers, veneeres, copings, crown-bridge frameworks, implants, piercing teeth, monolithic dental restorations, and their components.

[0038] Dental articles must not contain any components that are harmful to the patient's health, and therefore must not contain any harmful or toxic components that may transfer from dental or orthodontic articles.

[0039] "Additive manufacturing" or "3D printing" refers to a process that involves creating an object layer by layer from digital data. Articles can be almost any shape or form and are made from a three-dimensional model or other electronic data source. For the purposes of this specification, the term "additive manufacturing" is understood to mean "3D printing."

[0040] Many 3D printing technologies exist, one of which is tank polymerization, which uses radiation curing processes to create three-dimensional objects.

[0041] Examples of tank polymerization techniques include stereolithography (SLA) and digital photolithography (DLP).

[0042] Stereolithography is an example of additive manufacturing technology that typically uses two motors to cure the printing resin by aiming a laser beam across the entire printing area. This process breaks down the design into a series of points, layer by layer.

[0043] In stereolithography, light is generally used to solidify radiation-curable resins. Data based on computer-aided design and / or computer-aided manufacturing (CAD / CAM) is used to project a light pattern onto a layer of radiation-curable resin. The radiation-curable resin typically hardens as a result of exposure to light, forming layers of hardened resin according to the pattern. A three-dimensional object is created by continuously layering these resins. Therefore, the pattern is controlled according to the desired shape of the three-dimensional object.

[0044] "Digital light processing" is another example of additive manufacturing technology, typically involving the use of a digital projector screen to flash an image of each layer across the build platform of the additive manufacturing unit. The image is typically composed of square pixels, resulting in layers formed from small rectangular bricks called voxels.

[0045] Typically, layers have a specific thickness along the build axis. The build axis typically extends to the dimension in which layers are stacked on top of each other. In the dimension perpendicular to the build axis, each layer typically has a shape derived from the entire three-dimensional geometry of the object. Typically, layers are obtained by virtually slicing a three-dimensional computer model of an object into a number of virtual layers. These virtual layers are then used to build up physical layers that correspond to the virtual layers in terms of thickness and geometry.

[0046] The phrase "light suitable for solidifying radiation-curable materials" preferably refers to light with a wavelength of 450 nm to 495 nm (blue light), or light with a wavelength of 330 nm to 445 nm, preferably 383 nm (ultraviolet light). The light used in the methods described herein can be selected depending on the radiation-curable material used to build up the object.

[0047] "Glass ionomer cement" typically refers to a dental cement that hardens through a reaction between acid-reactive glass and polyacid in the presence of a retarder and water. Glass ionomer cement typically contains the following components: acid-reactive filler, polyacid, water, and complexing agent, but does not contain radiation-curing components.

[0048] "Resin-modified glass ionomer cement" refers to a hardening dental material containing acid-reactive glass, polyacid, water, polymerizable components, and initiators. Resin-modified glass ionomer cement undergoes a double hardening reaction: a glass ionomer acid-base based cementation reaction and polymerization of typically (meth)acrylate monomers.

[0049] "Adhesive resin cement" refers to a hardening dental material that cures through radical polymerization of polymerizable components (but not through the glass ionomer cement reaction). Adhesive resin cement requires pretreatment of a hard tooth surface to achieve adhesion. In contrast to resin-modified glass ionomer cement, adhesive resin cement does not contain additional water.

[0050] Self-adhesive resin cement is an adhesive resin cement that further contains acidic components and therefore does not require pretreatment of a hard tooth surface to achieve adhesion. In contrast to resin-modified glass ionomer cement, adhesive resin cements and self-adhesive resin cements typically harden only by polymerization reactions.

[0051] "Temporary cement" refers to a cement composition based on the hardening reaction between a zinc component (e.g., ZnO) and a phosphate, polycarboxylate, or eugenol component. These cements are known as zinc phosphate cement, zinc oxide eugenol cement, and zinc polycarboxylate cement, respectively.

[0052] "Glass" refers to an inorganic, nonmetallic, amorphous material that is a thermodynamically supercooled and solidified molten material. Glass is a hard, brittle, transparent solid. Typical examples include soda-lime glass and borosilicate glass. Glass is an inorganic product of a fusion that has been cooled to a rigid state without crystallization. Most glasses contain silica as their main component and a certain amount of glass-forming agent.

[0053] A "particle" refers to a solid substance that has a geometrically measurable shape. Its shape may be regular or irregular. Particles can typically be analyzed in terms of, for example, particle size and particle size distribution.

[0054] The average particle size of a powder is obtained from the integration curve of the particle size distribution and is defined as the arithmetic mean of the measured particle sizes of a particular powder mixture. Each measurement can be performed using a commercially available particle size analyzer (e.g., CILAS Laser Diffraction Particle Size Analysis Instrument).

[0055] "Ambient conditions" means the conditions to which the compositions described herein are typically exposed during storage and handling. Ambient conditions may be, for example, a pressure of 900 mbar to 1,100 mbar, a temperature of 10°C to 40°C, and a relative humidity of 10% to 100%. In a dental laboratory, ambient conditions are typically adjusted to 20°C to 25°C and 1000 mbar to 1025 mbar (at sea level).

[0056] If a composition does not contain a particular component as an essential feature, the composition is "essentially or substantially free" of that component. Therefore, this component is not intentionally added to the composition, either by itself or in combination with other components or ingredients containing other components. A composition that is essentially free of a particular component usually contains that component entirely. However, it may be unavoidable that small amounts of this component may be present, for example, due to impurities in the raw materials used.

[0057] As used herein, “a,” “an,” “the,” “at least one,” and “one or more” are interchangeable. Furthermore, in this specification, a numerical range described by endpoints includes all numbers contained within that range (for example, 1 to 5 includes 1, 1.5, 2, 2.75, 3, 3.80, 4, 5, etc.).

[0058] Adding "(s)" to a term means that the term should include both singular and plural forms. For example, the term "additive(s)" means one additive and two or more additives (e.g., two, three, four, etc.).

[0059] Unless otherwise indicated, all numbers used in this specification and in the claims to represent the quantity of a substance, measured physical properties, etc., such as those listed below, should be understood to be modified in all examples by the term “approximately”.

[0060] The terms “contains” or “includes” and their variations shall not be limited in meaning when used herein and in the claims. “Essentially consists of” means that certain further components may be present, i.e., components that do not substantially affect the essential properties of the article or composition. “Consists of” means that further components should not be present. The term “contains” also includes the terms “essentially consists of” and “consists of.” [Brief explanation of the drawing]

[0061] [Figure 1] A schematic diagram of the process steps according to the present invention is shown. [Modes for carrying out the invention]

[0062] The processes described herein have been found to have several advantageous characteristics.

[0063] The process described herein enables easy surface modification of 3D printed articles obtained or obtainable by additive manufacturing techniques involving layer-by-layer radiation curing of radiation-curable compositions.

[0064] After curing the radiation-curable composition layer by layer and removing the resulting 3D-printed article from the remaining radiation-curable composition, a thin, uncured layer of the radiation-curable composition still remains on the surface of the three-dimensional article.

[0065] The layer of this radiation-curable composition can be used, at least partially, in a surface modification process that involves treating, modifying, or embedding particles in the layer.

[0066] The particles are embedded in this layer before the final curing process takes place.

[0067] Not all particles are completely embedded; some are only partially embedded. This results in an increase in surface roughness.

[0068] In addition, the surface of a 3D-printed article is modified in that the surface typically contains additional particles that have different physical and / or chemical properties from the material from which the 3D-printed article is made.

[0069] Therefore, by selecting particles and processing conditions, the surface roughness and / or surface properties of 3D printed articles can be easily modified.

[0070] For example, one possible embodiment for cleaning the surface of a 3D printed article is the use of a so-called "spin cleaning process," which allows for easy adjustment of the thickness of the non-cured radiation-curable composition layer.

[0071] Higher surface roughness is often considered advantageous because it allows for more retaining elements to be available on the surface.

[0072] This typically allows for better and more robust adhesion when 3D printed articles are bonded to a surface by using a suitable adhesive composition or cement.

[0073] The final curing of a 3D printed article results in a 3D printed article having a surface in which particles are then incorporated and fixed.

[0074] The additional surface roughening process for three-dimensional objects is no longer required.

[0075] The processes described herein can be used not only to manufacture 3D printed articles on an industrial scale, but also to manufacture individualized single 3D printed articles, for example, to manufacture 3D printed dental composite crown chairsides, or in dental laboratories.

[0076] Since the particles are typically only partially embedded on the surface, the rest of the particles are available for further interaction with different media, such as adhesive compositions or cement.

[0077] Depending on the particles used, the processes described herein enable surface modification of the surface of 3D printed articles in various aspects.

[0078] For example, particles that can chemically interact with components present in a composition or cement used to fix a 3D printed article to a surface can be used.

[0079] This opens up opportunities to use a variety of different adhesive compositions or cements for fixing 3D printed articles to surfaces, including tooth surfaces, including the use of glass ionomer cement.

[0080] It is also possible to use particles that help improve or modify the mechanical properties of 3D printed articles.

[0081] This represents a groundbreaking advance in the field of dentistry, because until now, dental composite crowns could not be bonded at all with, for example, glass ionomer cement.

[0082] The option of having a readily available process that allows dentists to use glass ionomer cement to fix 3D-printed dental composite crowns to the tooth surface is advantageous for several reasons.

[0083] Glass ionomer cements are typically less expensive than self-adhesive resin cements. Furthermore, they are typically more moisture-resistant and easier to apply.

[0084] This invention relates to a process for surface modification of three-dimensional materials, particularly for manufacturing 3D printed articles.

[0085] This process involves a series of steps. Typically, a radiation-curable composition is provided first.

[0086] The properties and chemical composition of the radiation-curable composition are not particularly limited, as long as they do not make the radiation-curable composition unsuitable for its intended use.

[0087] Radiation-curable compositions typically have the following characteristics: It must be curable by radiation having wavelengths in the range of 350nm to 600nm or 350nm to 420nm. Viscosity: 1s -1 At a shear rate of 23°C, 1 Pa * s~400Pa * s, or 5 Pa * s~200Pa * s, or 5 Pa * s~100Pa * Being s, pH value: When in contact with moistened pH-sensitive paper, it should be 5-9 or 6-8. It can be characterized by one or a combination of these.

[0088] If desired, the characteristics can be measured as described in the Examples section.

[0089] In certain embodiments, a combination of the following features: a) and b), or a), b) and c) may be desirable.

[0090] In a particular embodiment, the following characteristics are observed: It is curable by radiation with wavelengths in the range of 350 nm to 420 nm. Viscosity: 1 s -1 at a shear rate of -1 and 5 Pa at 23 °C * s ~ 100 Pa * s, and pH value: when contacted with wetted pH-sensitive paper, it should be 6 - 8, it is sometimes preferable to use a radiation-curable composition having .

[0091] The curable composition described herein is radiation-curable within the wavelength range typically used in commercially available additive manufacturing devices.

[0092] Furthermore, the curable composition described herein typically has a viscosity that enables processing of the composition in SLA or DLP processes. A lower viscosity may be sometimes preferable as it may enable better printing quality, particularly with regard to surface accuracy.

[0093] Since the curable composition typically does not contain acidic components, the pH value of the composition is in the neutral range.

[0094] The resin material used in the additive manufacturing process typically includes a (meth)acrylate component and a photoinitiator suitable for initiating the curing reaction of the radiation-curable composition.

[0095] It may be advantageous if the radiation-curable composition contains a radiation-curable (meth)acrylate component containing at least one urethane moiety.

[0096] The molecular weight of the (meth)acrylate is typically at least 170, or at least 200, or at least 300 g / mol. The molecular weight (Mw) of the (meth)acrylate is typically in the range of 170 g / mol - 3,000 g / mol, or 200 g / mol - 2,500 g / mol, or 300 g / mol - 2,000 g / mol.

[0097] (Meth)acrylate has free radical active functional groups and includes monomers, oligomers, and polymers having two or more ethylenically unsaturated groups.

[0098] Such free radical polymerizable materials include di- or polyacrylates and methacrylates, for example, glycerol diacrylate, glycerol triacrylate, ethylene glycol diacrylate, diethylene glycol diacrylate, triethylene glycol dimethacrylate, 1,3-propanediol diacrylate, 1,3-propanediol dimethacrylate, trimethylolpropane triacrylate, 1,2,4-butanetriol trimethacrylate, 1,4-cyclo-hexanediol diacrylate, pentaerythritol triacrylate, pentaerythritol tetraacrylate, penta-erythritol Examples include tetramethylmethacrylate, sorbitol hexaacrylate, bis[1-(2-acrylooxy)]-p-ethoxyphenyldimethylmethane, bis[1-(3-acrylooxy-2-hydroxy)]-p-propoxyphenyl-dimethylmethane, bisacrylates and bis-methacrylates of polyethylene glycol with molecular weights of 200 to 500, copolymerizable mixtures of acrylic monomers such as those specified in U.S. Patent No. 4,652,274, and acrylic oligomers such as those specified in U.S. Patent No. 4,642,126; and vinyl compounds, such as diallyl phthalate, divinyl succinate, divinyl adipate, and divinyl phthalate.

[0099] Preferred ethylenically unsaturated monomers include methacrylate and acrylate monomers such as di(meth)acrylates of propanediol, butanediol, hexanediol, octanediol, nonanediol, decanediol, and eicosanediol; di(meth)acrylates of ethylene glycol, polyethylene glycol, and polypropylene glycol; di(meth)acrylates of ethoxylated bisphenol A, e.g., 2,2'-bis(4-(meth)-acrylooxytetraethoxyphenyl)propane; and (meth)acrylamide. The monomers used may further be esters of [alpha]-cyanoacrylic acid, crotonic acid, cinnamic acid, and sorbic acid.

[0100] (Meth)acrylic esters, e.g., bis[3[4]-methacryl-oxymethyl-8(9)-tricyclo[5.2.1.0 2,6 Decylmethyl triglycolate can also be used. Particularly preferred are 2,2-bis-4(3-methacrylate-oxy-2-hydroxypropoxy)phenylpropane (Bis-GMA), 2,2-bis-4(3-methacrylate-oxypropoxy)phenylpropane, triethylene glycol dimethacrylate (TEGDMA), and bishydroxymethyl-tricyclo(5.2.1.0 2,6 It is a di(meth)acrylate of decane. A suitable methacrylate ester is also described in European Patent No. 0235826(A1) (ESPE).

[0101] It has been found that using (meth)acrylate, more specifically the above-mentioned components, can be beneficial in providing a solidified composition with sufficient mechanical strength, as it can function as a type of crosslinking agent useful in improving the mechanical properties of the hardened dental composition.

[0102] If present, the (meth)acrylate component is typically present in the following amounts: Lower limit: at least 40, or at least 45, or at least 50% by weight, Maximum amount: up to 85% by weight, or up to 80% by weight, or up to 70% by weight. Range: 40% to 85% by weight, or 45% to 80% by weight, or 50% to 70% by weight. It exists as follows. The weight percentage here is relative to the weight of the radiation-curable composition.

[0103] The radiation-curable compositions described herein typically include initiator systems, particularly photoinitiator systems.

[0104] The initiator system is typically present in amounts of 0.1% to 5% by weight, 0.2% to 4% by weight, or 0.5% to 3% by weight.

[0105] Initiator systems typically include a photoinitiator and an organic dye.

[0106] Initiator systems contribute to the efficient curing of curable compositions, control light transmittance and light scattering, and therefore can affect mechanical and aesthetic properties.

[0107] A photoinitiator should be able to initiate or cause to initiate the curing or solidification reaction of radiation-curable components present in a radiation-curable composition.

[0108] Photoinitiators typically exhibit a light absorption band in the wavelength range of 300 nm to 450 nm, preferably in the range of 350 nm to 420 nm.

[0109] A preferred example of a photoinitiator typically contains a phosphine oxide moiety.

[0110] Examples of photocuring initiator components include, for example, acylphosphine oxides, such as those described in U.S. Patent No. 4,737,593 (Elrich et al.).

[0111] Such acylphosphine oxides have the general formula (R 9 )2-P(=O)-C(=O)-R 10 (In the formula, each R 9 Each of these may be a hydrocarbyl group such as alkyl, cycloalkyl, aryl, and aralkyl, and any of them may be substituted with a halo-, alkyl-, or alkoxy group, or two R 9 The group can bond and form a ring with the phosphorus atom, R 10 This is a hydrocarbyl group, an S-, O-, or N-containing 5 or 6-membered heterocyclic group, or -ZC(=O)-P(=O)-(R 9 ) There are two groups (wherein Z represents a divalent hydrocarbyl group such as alkylene or phenylene having 2 to 6 carbon atoms).

[0112] A preferred acylphosphine oxide is R9 and R 10 The group is phenyl, or a lower alkyl- or lower alkoxy-substituted phenyl. "Lower alkyl" and "lower alkoxy" refer to such groups having 1 to 4 carbon atoms.

[0113] A tertiary amine reducing agent may be used in combination with an acylphosphine oxide. Examples of tertiary amines include ethyl 4-(N,N-dimethylamino)benzoate and N,N-dimethylaminoethyl methacrylate.

[0114] Commercially available phosphine oxide photoinitiators capable of initiating free radicals when irradiated at wavelengths exceeding 400 nm and up to 1200 nm include: a 25:75 weight ratio mixture of bis(2,6-dimethoxybenzoyl)-2,4,4-trimethylpentylphosphine oxide and 2-hydroxy-2-methyl-1-phenylpropan-1-one (IRGACURE® 1700, formerly known as Ciba Specialty Chemicals); 2-benzyl-2-(N,N-dimethylamino)-1-(4-morpholinophenyl)-1-butanone (IRGACURE® 369, formerly known as Ciba Specialty Chemicals); and bis(η5-2,4-cyclopentadien-1-yl)-bis(2,6-difluoro-3-(1H-pyrrole-1-yl)phenyl) titanium (IRGACURE® 784 DC, Ciba Specialty Chemicals). Examples include bis(2,4,6-trimethylbenzoyl)phenylphosphine oxide and 2-hydroxy-2-methyl-1-phenylpropan-1-one in a 1:1 weight ratio mixture (DAROCUR® 4265, previously known as Ciba Specialty Chemicals), ethyl-2,4,6-trimethylbenzylphenylphosphine (LUCIRIN® LR8893X, BASF Corp., Charlotte, NC), and 2,4,6-trimethylbenzoyldiphenylphosphine oxide (LUCIRIN® TPO).

[0115] Examples of UV initiators include 1-hydroxycyclohexylbenzophenone (formerly known as "IRGACURE 184" from Ciba Specialty Chemicals Corp., (Tarrytown, NY)), 4-(2-hydroxyethoxy)phenyl-(2-hydroxy-2-propyl)ketone (formerly known as "IRGACURE 2529" from Ciba Specialty Chemicals Corp.), 2-hydroxy-2-methylpropiophenone (formerly known as "DAROCURE D111" from Ciba Specialty Chemicals Corp.), and bis(2,4,6-trimethylbenzoyl)-phenylphosphine oxide (formerly known as "IRGACURE 819" from Ciba Specialty Chemicals Corp.). The most preferred acylphosphine oxide is bis(2,4,6-trimethylbenzoyl)phenylphosphine oxide (OMNIRAD® 819, IGM Resin BV, Waalwijk, NL).

[0116] The photoinitiator is typically used in the following amounts: Lower limit: at least 0.01% by weight, or at least 0.05% by weight, or at least 0.1% by weight. Maximum amount: up to 3% by weight, or up to 2% by weight, or up to 1.5% by weight. Range: 0.01% by weight to 3% by weight, or 0.05% by weight to 2% by weight, or 0.1% by weight to 1.5% by weight. It exists as follows. The weight percentage here is relative to the weight of the radiation-curable composition.

[0117] The polymerizable compositions described herein typically also include one or more organic dyes.

[0118] The properties and structure of organic dyes are not particularly limited, as long as the desired results can be achieved.

[0119] It has been found that the radiation-absorbing ability of the polymerizable compositions described herein can be improved by adding organic dyes.

[0120] Furthermore, the addition of organic dyes has been found to contribute to suppressing or reducing the transmittance of scattered light in polymerizable compositions. This often helps to improve the surface accuracy or fine detail resolution of three-dimensional articles obtained from additive manufacturing processes.

[0121] In a particular embodiment, the organic dye has the following parameters: a) Having an optical absorption band in the wavelength range of 350 nm to 420 nm. b) It does not have an optical absorption band in the wavelength range of 400 nm to 800 nm. c) Includes the terephthalate portion. It may feature at least one, or more, of all of them.

[0122] A combination of parameters a) and b) may be preferable.

[0123] Suitable organic dyes include those containing a terephthalate group and / or an aromatic (heterocyclic) ring, or a moiety selected from other systems having delocalized π electrons. In particular, dyes useful for coloring food have been found to be useful.

[0124] Suitable dyes include Lumilux® Blue, Lumilux® Yellow (Honeywell), and mixtures thereof.

[0125] If organic dyes are present, use the following amounts: Lower limit: at least 0.001% by weight, or at least 0.002% by weight, or at least 0.005% by weight. Maximum amount: up to 0.5% by weight, or up to 0.2% by weight, or up to 0.1% by weight. Range: 0.001% by weight to 0.5% by weight, or 0.002% by weight to 0.2% by weight, or 0.005% by weight to 0.1% by weight. It exists as follows. The weight percentage here is relative to the weight of the radiation-curable composition.

[0126] The radiation-curable compositions described herein typically include a filler matrix.

[0127] The filler matrix is ​​typically present in the radiation-curable composition in an amount of 5% to 45% by weight, or 10% to 40% by weight.

[0128] The amount of filler used may affect the viscosity of the radiation-curable composition, the wear resistance of the cured composition, or both.

[0129] The packing matrix may contain fumed silica.

[0130] The specific surface area (BET) of fumed silica is typically 100 m². 2 / g~300m 2 / g, or 150m 2 / g~250m 2 It is within the range of / g.

[0131] If desired, a mixture of different fumed silica can be used.

[0132] For example, a mixture of fumed silica whose surface is treated with a hydrophobic surface treatment agent and fumed silica whose surface is treated with a hydrophilic surface treatment agent may be used.

[0133] A suitable hydrophobic surface treatment agent is -OSiR3 (wherein R is C 1~4 It contains alkyl, preferably methyl, and mixtures thereof.

[0134] Hydrophobic fumed silica is also marketed under the trade names HDK, particularly HDK-H(trademark)2000(Wacker), or Aerosil(trademark)R812(Evonik).

[0135] It has been found that using fumed silica whose surface is treated with a surface treatment agent containing polymerizable moieties such as (meth)acrylsilane can result in undesirable thickening of the curable composition, which can make the curable composition less suitable as a processing material in additive manufacturing processes.

[0136] Accordingly, according to one embodiment, the curable compositions described herein typically do not contain fumed silica surface-treated with a surface treatment agent containing a polymerizable moiety such as (meth)acrylsilane in amounts exceeding 2% by weight, 1.5% by weight, or 1% by weight relative to the weight of the radiation-curable composition.

[0137] If present, fumed silica is typically present in the following amounts: Lower limit: at least 0.5% by weight, or at least 1% by weight, or at least 1.5% by weight. Maximum amount: up to 8, or up to 7, or up to 5% by weight. Range: 0.5% by weight to 8% by weight, or 1% by weight to 7% by weight, or 1.5% by weight to 5% by weight. It exists in one of the following states. The weight percentage here is relative to the weight of the radiation-curable composition.

[0138] The filler matrix may also contain nanoclusters.

[0139] One or more different types of nanoclusters can exist.

[0140] Compared to other fillers using nanoclusters, it has been found that this can be beneficial because it allows for the formulation of compositions with higher filler content, typically resulting in better mechanical properties, such as abrasion resistance or wear resistance, and higher aesthetics.

[0141] Nanoclusters typically have the following characteristics: Specific surface area (BET): 30m 2 / g~400m 2 / g, or 60m2 / g~300m 2 / g, or 80m 2 / g~250m 2 It is / g Containing particles of SiO2, ZrO2, Al2O3, and mixtures thereof; Characterized by at least one or all of the following:

[0142] If desired, the specific surface area can be determined according to the Brunauer-Emmett-Teller (BET) formula using a device available from Quantachrome (Monosorb®).

[0143] Suitable nanofillers containing aggregated nano-sized particles can be manufactured, for example, by following the process described in U.S. Patent No. 6,730,156 (Preparation Example A).

[0144] Useful nanofillers containing aggregated nano-sized particles can be prepared from a suitable sol and one or more oxygen-containing heavy metal compound solution precursors, which may be salts, sols, solutions, or nano-sized particles, of which sols are preferred.

[0145] If desired, the surface of the filler particles can be surface-treated. Surface treatment can be achieved according to the process described in U.S. Patent No. 6,730,156 (Windisch et al.) or U.S. Patent No. 6,730,156 (Wu et al.). The contents of these references are incorporated herein by reference.

[0146] When dispersed in the resin, the filler remains in the aggregated state. That is, during the dispersion process, the particles are not broken down into discrete (i.e., individual) particles and non-aggregated (i.e., non-aggregated) particles.

[0147] If present, nanoclusters are typically found in the following quantities: Lower limit: at least 5% by weight, or at least 10% by weight, or at least 15% by weight. Maximum amount: up to 40, or up to 38, or up to 35% by weight. Range: 5% to 40% by weight, or 10% to 38% by weight, or 15% to 35% by weight. It exists in one of the following states. The weight percentage here is relative to the weight of the radiation-curable composition.

[0148] Radiation-curable compositions can be obtained by mixing their respective components, preferably under savelight conditions.

[0149] Typical radiation-curable compositions include the following components: (Meth)acrylate component: 40% to 85% by weight, Photoinitiator: 0.01% to 3% by weight, Filler: 5% to 45% by weight, Organic dye: 0.001% to 0.5% by weight, It may include. The weight percentages here refer to the weight of the radiation-curable composition.

[0150] Suitable radiation-curable resin materials are also, It is a resin matrix, Polymerizable (meth)acrylate that does not contain urethane, and Contains polymerizable urethane (meth)acrylate, A resin matrix in which polymerizable (meth)acrylate without the urethane portion is used in excess of polymerizable urethane (meth)acrylate, A filler matrix, Nanoclusters, and Optionally, containing less than 8% by weight of fumed silica, Typically, the packing matrix is ​​present in an amount of 5% to 45% by weight, It is an initiator system, Photoinitiator, and An initiator system containing an organic dye, Radiation-curable composition, 23°C and 1 s -1 At a shear rate of 100 Pa * It can be characterized as having a viscosity of s or less.

[0151] Suitable radiation-curable resin materials are also described in International Publication No. 2018 / 231583(A1)(3M). The contents of these references are incorporated herein by reference.

[0152] Suitable radiation-curable compositions are also commercially available, such as SHERAprint®-cast or SHERAprint®-model or Prodways PLASTCure®-Cast200 or Prodways PLASTCure®-Model300.

[0153] The process of the present invention further includes a step of building up a three-dimensional article by radiation-curing a radiation-curable composition layer by layer.

[0154] The build-up of three-dimensional objects by layer-by-layer additive manufacturing is a well-known technique. This technique is often also called stereolithography or digital light processing.

[0155] According to one embodiment, the additive manufacturing process is A step of providing a layer of radiation-curable composition on a surface, A process of radiation-curing a layer of a radiation-curable composition that will become part of a three-dimensional article to be manufactured, A step of providing a further layer of radiation-curable composition in contact with the radiation-cured surface of the previous layer, This includes a step of repeating the previous step until a three-dimensional object is obtained.

[0156] Such a process involves applying radiation to the surface of a radiation-curable material, where the radiation is applied only to the surface portion that will later form part of the article being manufactured.

[0157] Radiation can be applied, for example, by using a laser beam or by projecting a mask image. The use of a stereolithography process based on mask image projection (MIP-SL) is sometimes preferred because it allows for faster manufacturing of the article.

[0158] The MIP-SL process can be described as follows: i. Prepare a 3D digital model of the item to be manufactured. ii. Slice the 3D digital model using a series of horizontal planes. iii. Convert each thin slice into a two-dimensional mask image. iv. Next, the mask image is projected onto the surface of the radiation-curable material placed on the build platform (for example, having the shape of a bat) using a radiation source. v. Radiation-curable materials are cured only within the exposed area. vi. Move a build platform containing a layer of radiation-curable material or a cured material relative to a radiation source to provide a new layer of radiation-curable material in contact with the layer of cured material produced in the previous step. vii. Repeat steps (iv) to (vi) until the desired article is formed.

[0159] The projection of the mask image onto the radiation-curable material can be performed either downwards or upwards, relative to the orientation of the bat.

[0160] Using upward techniques may be beneficial because it requires less radiation-curable material.

[0161] In this process, a radiation-cured layer is formed on the bottom of a transparent tray.

[0162] The radiation-curable compositions described herein have been found to be particularly useful for processing in mask image projection stereolithography processes using upward projection techniques.

[0163] Suitable process parameters for the SLA process include radiation wavelength: 350 nm to 420 nm, curing time: 0.5 seconds to 20 seconds, and layer thickness: 1 μm to 100 μm.

[0164] The available technologies and equipment are commercially available from companies such as 3Shape, Rapid Shape, Formlabs, Lithoz, Prodways, Stratasys, and EnvisionTec.

[0165] Additive manufacturing devices typically operate at a specific radiation wavelength within the range of 350 nm to 420 nm. Additive manufacturing devices can also be characterized by the resolution they can achieve. Preferred resolutions are typically in the range of 5 μm to 100 μm, 10 μm to 80 μm, or 20 μm to 60 μm.

[0166] The process described herein further includes a step of partially removing a radiation-curable composition that is fixed or adhered to the surface of a three-dimensional article.

[0167] During the additional build-up process, the 3D article is constructed layer by layer, and the 3D article remains in contact with the radiation-curable composition from which the 3D article is fabricated.

[0168] This is a result of some of the uncured radiation-curable composition remaining on the surface of the three-dimensional article.

[0169] Furthermore, before use, any remaining radiation-curable composition is typically completely removed to ensure better surface quality and precision of the desired three-dimensional article.

[0170] However, it has been found that partial removal can be beneficial because the radiation-curable composition still remaining on the surface of the three-dimensional article can be used to further modify the surface of the three-dimensional article, for example, by absorbing or fixing additional particles on the surface of the three-dimensional article to obtain a surface-modified three-dimensional article.

[0171] Therefore, after partial removal of the radiation-curable composition, some of the radiation-curable composition remains on the surface of the three-dimensional article. This remaining radiation-curable composition forms a layer on the surface.

[0172] The amount of residual radiation-curable composition typically depends on the structure and shape of the three-dimensional article, as well as the viscosity of the radiation-curable composition used to construct the article.

[0173] For example, in the case of a three-dimensional object having the shape of a rectangular parallelepiped (25mm x 10mm x 5mm), 5 Pa * s~100Pa * Viscosity in the range of s (at 23°C and 1 s) -1 The amount of residual radiation-curable composition having a shear rate of is typically in the range of 0.05% to 20% by weight, or 0.1% to 10% by weight, or 0.2% to 5% by weight.

[0174] The thickness of the layer formed by the remaining radiation-curable composition is typically in the range of 1 μm to 500 μm, 5 μm to 200 μm, or 10 μm to 100 μm.

[0175] Different techniques can be used for the removal or partial removal of radiation-curable compositions.

[0176] One technique that can be used involves the process of moving or rotating a three-dimensional object. By doing so, a mass inertial force is generated.

[0177] The term "mass inertial force," when referred to herein, may be defined as force per unit mass, and therefore, in units of m / s². 2 It can be defined as follows. Furthermore, the mass inertial force can be expressed by the G force, which is an element of gravitational acceleration. For the purposes of this specification, the gravitational acceleration is 9.81 m / s². 2 Therefore, for example, 9.81 m / s 2 The inertial force of the mass can be expressed as 1G.

[0178] Accelerating forces or mass inertial forces are induced by moving an object, for example, by rotating it.

[0179] The centrifugal force on a particle on the surface of a three-dimensional object depends on the rotational speed and the radius at which the particle is located relative to the axis of rotation.

[0180] By adjusting various parameters such as the speed of movement or rotation, its duration, and / or the axis of rotation, this technology allows for the adjustment of the amount and thickness of the radiation-curable composition remaining on the surface of a three-dimensional article.

[0181] In the embodiment, the mass inertial force generated in step (c) corresponds to a G force of at least 100 G. A mass inertial force of 100 G has been proven suitable for removing medium-to-high viscosity radiation-curable materials. Those skilled in the art will recognize that the mass inertial force required for cleaning step (c) may be lower for lower viscosity materials and higher for higher viscosity materials.

[0182] The following parameters were found to be useful: [Table 1]

[0183] Such processes or techniques are described, for example, in International Publication No. 2019 / 023120(A1)(3M). The contents of this reference are incorporated herein by reference.

[0184] Another technique that can be used involves treating a three-dimensional article with a cleaning composition.

[0185] Depending on the amount of cleaning composition used and the processing time, the amount of radiation-curable composition remaining on the surface and the thickness of the layer can be adjusted.

[0186] A suitable cleaning composition contains an alcohol such as ethanol or isopropanol.

[0187] Particularly useful are cleaning compositions containing, either alone or in combination, the following components: dibasic esters and / or tribasic esters of carboxylic acids.

[0188] Particularly preferred are cleaning compositions comprising a dibase ester of a carboxylic acid in an amount of 25% to 100% by weight, a tribase ester of a carboxylic acid in an amount of 1% to 25% by weight, and a solvent having a boiling point above 100°C in an amount of 1% to 75% by weight.

[0189] Such cleaning compositions are described in International Publication No. 2018 / 222395(A1)(3M). The contents of this reference are incorporated herein by reference.

[0190] If necessary, the cleaning composition may be used in combination with a cleaning apparatus, for example, the apparatus described in International Publication No. 2019 / 111208(A1)(3M). The contents of that reference are incorporated herein by reference.

[0191] Radiation-curable compositions can also be simply removed by using gravity.

[0192] A three-dimensional article containing a radiation-curable composition on its surface is simply stored or placed in a manner that allows the radiation-curable composition to fall or flow off the surface due to its own weight.

[0193] Alternatively, or in addition, the radiation-curable composition can be partially removed by applying or using a gas stream (e.g., air or nitrogen).

[0194] The process described herein further includes the step of treating only a portion of the surface of a three-dimensional article to which a radiation-curable composition is attached with particles.

[0195] In other words, it is not necessary to treat the entire surface of a three-dimensional object. If only a portion of the surface of the three-dimensional object is treated with particles, that may already be sufficient. However, if necessary, it is also possible to treat the entire surface of the three-dimensional object.

[0196] The preferred portion or part of the surface of the three-dimensional article to be processed is typically in the range of 10% to 80%, 20% to 70%, or 30% to 60%.

[0197] The particle processing steps can be adjusted, for example, to achieve a surface roughness of a three-dimensional article within the range of 1 μm (Ra) to 20 μm (Ra) or 2 μm (Ra) to 10 μm (Ra).

[0198] Surface roughness within this range may be beneficial for facilitating the bonding or adhesion of other materials or compositions to the surface of a three-dimensional article.

[0199] Adjusting the processing steps typically involves selecting suitable particles with desired particle size and parameters (e.g., applied pressure, duration, particle flow rate) that are suitable for processing these particles. Pre-selection of suitable parameters is often already provided by the device used in the surface roughening process.

[0200] The particles can be applied by various means to a layer of radiation-curable composition located on the surface of a three-dimensional article.

[0201] A preferred method is the use of a gas stream. Such a processing step can be considered a type of sandblasting or powder jetting.

[0202] Devices that can be used to apply particles to a surface under pressure are commercially available, such as Rocatec® (3M Oral Care), Basic Classic (Renfert), and Airflow® (EMS).

[0203] When particles are applied in a gaseous flow, the preferred operating pressure is typically in the range of 0.5 kPa to 500 kPa (5 bar) or 1 kPa to 300 kPa.

[0204] The preferred particle flow rates are typically in the range of 0.01 g / ~10 g / sec or 0.02 g / ~6 g / sec (e.g., at an operating pressure of 2 bar).

[0205] When applied in a gas flow, the particles are typically applied for a sufficient amount of time to achieve the desired surface roughness.

[0206] 1 cm to be processed 2 A time range of 0.1 to 10 seconds, 1 to 5 seconds, or 1 to 2 seconds per surface area is considered sufficient.

[0207] Alternatively, the sandblasting or powder spraying device may be vibrated during the processing step to avoid unwanted clumping of particles used in particle processing.

[0208] The particles may also be applied by other means, such as a coating process.

[0209] In such processes, particles are typically applied without the use of a gas flow, but if necessary, they are applied by using coating equipment such as a powder feeding unit combined with rollers.

[0210] For example, the coating process can be carried out by lightly pressing the uncured surface of a three-dimensional article with particles.

[0211] In contrast to the processes described herein, sandblasting of a cleaned and fully cured surface of a three-dimensional article for the purpose of surface roughening does not result in the incorporation or embedding of particles into the surface of the three-dimensional article.

[0212] The presence of particles on the surface of a three-dimensional object can be determined by various techniques, such as microscopy or XRF analysis.

[0213] According to a further embodiment, the particles are simply placed on the surface of the three-dimensional article to be processed, for example, by scattering or injection.

[0214] If the three-dimensional article has, for example, a concave surface area (e.g., the inside of a dental crown), the concave area can be filled with particles in the first step. In a further step, the three-dimensional article is rotated so that particles that do not adhere to the radiation-curable composition located on the surface simply fall off.

[0215] The properties and chemical composition of the particles used in the processing steps are not particularly limited, as long as the particles do not become unsuitable for their intended use.

[0216] The preferred particles have the following characteristics: Average particle size: 1μm~150μm, Density: 2g / cm 3 ~6g / cm 3 , It can be characterized by one or a combination of these.

[0217] The following features: Average particle size: 1μm~50μm, Density: 2g / cm 3 ~6g / cm 3 , Particles having the following properties can also be used.

[0218] Particle sizes within the above range are often beneficial because larger particles can typically be more readily embedded in radiation-curable compositions.

[0219] Furthermore, handling and processing particles with larger particle sizes is often not very complicated.

[0220] It may also be preferable that the size of the particles used in the processing is greater than the thickness of the layer of radiation-curable composition on the surface of the three-dimensional article. In such cases, it can be easily ensured that the particles are only partially embedded in the layer of radiation-curable composition. The unembedded portions of the particles can then protrude from the surface and approach the periphery.

[0221] It may also be beneficial to use particles with a particle size larger than the resolution of the additive manufacturing device used to build up the 3D object.

[0222] For three-dimensional articles having a thin layer of residual radiation-curable composition on their surface, it is possible to ensure that the surface roughness of the three-dimensional article increases due to the resolution that can be achieved by the additive manufacturing device.

[0223] Depending on the properties and / or chemical composition of the particles, they may be used as connectors or reaction partners for other compositions subsequently applied to the surface of a three-dimensional article.

[0224] Using particles with densities within the above range is considered beneficial because such particles are typically easier to process. For example, when these particles are processed in a sandblasting device, they have greater impact or momentum. 2 g / cm³ 3 Particles with a density exceeding a certain level are often composed of inorganic components.

[0225] Examples of particles that can be used include glass powder, metal oxides, or hydroxide powders, and mixtures thereof.

[0226] The glass powder includes, for example, so-called acid-reactive glass commonly used to produce glass ionomer cement compositions.

[0227] Acid-reactive glass is known in the art and is commercially available, for example, from Schott.

[0228] The use of acid-reactive glass may be beneficial when three-dimensional articles are intended to be bonded and fixed to a surface (e.g., a tooth surface) with dental cement, particularly glass ionomer cement.

[0229] Typical acid-reactive glasses include aluminosilicate glasses, particularly fluoroalumina-silicate ("FAS") glass. FAS glass is sometimes preferred.

[0230] Glass can be produced from a molten material containing fluoride, silica, alumina, and other glass-forming materials using techniques well known to those skilled in the art of FAS glass manufacturing technology.

[0231] Suitable FAS glass is well known to those skilled in the art and is available from a wide variety of commercial suppliers, and is often found in currently available glass ionomer cements, such as those marketed under trade names Ketac®-Molar or Ketac®-Fil Plus (3M Oral Care), and FUJIT M IX (GC).

[0232] Fluoroaluminosilicate glass can be prepared by melting a mixture of silica, alumina, cryolite, and fluorite.

[0233] Examples of metal oxide or hydroxide powders that can be used include oxides or hydroxides of Al, Si, Zr, Ba, Sr, Ca, Mg, Ag, and Zn, as well as mixtures thereof.

[0234] When the surface of a three-dimensional article needs to be more hydrophilic, the use of metal oxide powder can be beneficial. If necessary, the particles may be surface-treated, for example, with silane.

[0235] To improve particle processing and transport in sandblasting or powder spraying devices, the addition of free-flowing or anti-caking agents may be advantageous.

[0236] Suitable free-flow or anti-caking agents include silica powder (e.g., Aerosil™ from Evonik containing OX50, 130, 150, and 200; HDK™ from Wacker containing H15, H2O, and H200), silicate powder, or talcum powder, and mixtures thereof.

[0237] These free-flow or anti-caking agents typically have an average particle size in the range of 10 nm to 500 nm, or 10 nm to 200 nm.

[0238] When a free-flowing or anti-caking agent is used, the processing step is carried out with a particle mixture, i.e., a particle composition containing large and small particles.

[0239] A suitable particle composition may include particles having an average particle size of 1 μm to 150 μm, and particles having an average particle size of 10 nm to 500 nm.

[0240] When a free-flowing or anti-caking agent is used, it is typically present in the particulate composition in an amount of 0.05% to 5% by weight, or 0.1% to 3% by weight, relative to the amount of the particulate composition.

[0241] The process of the present invention further includes an additional curing step for a three-dimensional article.

[0242] This additional curing process can be carried out by heat, radiation, or a combination of both.

[0243] By applying an additional curing step, any remaining radiation-curable composition located on the surface of the three-dimensional article is cured. This fixes the particles embedded in the layer of radiation-curable composition, firmly bonding them to the three-dimensional article.

[0244] The post-curing process has the following characteristics: Applying radiation at wavelengths of 350nm to 450nm, Applying a heating process at 30°C to 120°C, or 40°C to 80°C, and can be characterized by at least one or all of them.

[0245] Devices that can be used to post-cure three-dimensional articles obtained by additive manufacturing are commercially available, for example, from Rapidsimple, 3Shape, EnvisonTEC, Formlabs, etc.

[0246] The process described herein is for manufacturing surface-modified three-dimensional articles, particularly 3D printed articles.

[0247] The present invention also aims at three-dimensional articles that can be obtained or are obtainable by such a process.

[0248] If necessary, the three-dimensional article has the following characteristics: Flexural strength: Measured in accordance with ISO 4049:2009 using a test bar having dimensions of 6 * 4 * 25 mm (6 mm being the width of the test bar), and being 50 MPa to 200 MPa, or 80 MPa to 150 MPa, Modulus of elasticity: Measured in accordance with DIN EN 843-2:2007 using the flexural strength method, and being 1,000 MPa to 4,000 MPa (the calculation of the modulus of elasticity is performed within the range of 20% and 50% of the maximum force of the sample), Impact strength: Measured in accordance with DIN 53453:175-05, and being 5 kJ / m 2 ~15 kJ / m 2 and can be characterized by the sole or combined presence thereof.

[0249] Sufficient flexural strength can be beneficial as the material of the three-dimensional article does not break easily.

[0250] Sufficiently low modulus of elasticity can be beneficial as the material of the three-dimensional article has sufficient flexibility.

[0251] Since the material of a three-dimensional object has high toughness and can resist fracture, sufficient impact strength can be beneficial.

[0252] The shape and dimensions of the three-dimensional article are not particularly limited.

[0253] Depending on the size and dimensions of the additive manufacturing process used, the size and dimensions of the three-dimensional object may also vary.

[0254] The processes described herein can be used to manufacture all kinds of three-dimensional articles that need to be modified by embedding or fixing particles on their surface.

[0255] Because this process is based on the use of additive manufacturing technology, it is particularly useful for three-dimensional articles with complex dimensions that cannot otherwise be easily manufactured by processes such as molding or grinding.

[0256] The x, y, and z dimensions of a three-dimensional object are typically less than 100 mm for each dimension, for example, between 1 mm and 50 mm for two dimensions, or between 2 mm and 30 mm.

[0257] The processes described herein are particularly useful in the dental and orthodontic fields because dental and orthodontic articles typically have complex structures, and may require specific surface treatments and fixation of the dental or orthodontic articles to the tooth surface.

[0258] As an example, the process described herein can be used to manufacture dental restorations, particularly dental restorations having the shape of a dental crown or bridge.

[0259] Dental or orthodontic articles can often be characterized by having an outer surface and an inner surface. The outer surface is the surface that remains visible after the dental article is fixed to the tooth structure, while the inner surface is the surface that is intended to be fixed to the tooth structure.

[0260] In one embodiment, the three-dimensional article has the shape of a dental restoration having an outer surface and an inner surface, and only the inner surface of the three-dimensional article contains particles partially embedded therein.

[0261] The three-dimensional article is typically composed of a composition containing a cured (meth)acrylate component and a filler, and the maximum particle size of the filler is typically less than 1 μm.

[0262] The three-dimensional article further includes a section or layer of a cured radiation-curable component on its inner surface that contains particles having an average particle size greater than 1 μm, for example, in the range of 2 μm to 100 μm.

[0263] As described above, the thickness of the layer of the cured radiation-curable component can be in the range of 1 μm to 500 μm, or 5 μm to 200 μm, or 10 μm to 100 μm.

[0264] Such a three-dimensional article can also be produced by a process comprising providing a three-dimensional article (e.g., a dental or orthodontic article having an outer surface and an inner surface), applying a layer of a radiation-curable composition on the inner surface of the three-dimensional article, treating at least a part of the surface of the three-dimensional article to which the radiation-curable composition is attached with particles, and applying a curing process to the three-dimensional article, preferably by applying heat and / or radiation, wherein each component or particle is as described herein. According to a preferred embodiment, the dental article has the shape of a dental composite crown.

[0265]

[0266] The shape of the dental composite crown is typically characterized by the following.

[0267] ​​​​The crown has an upper surface, a dependent buccal surface, and palatal surfaces, respectively, the labial, mesial, distal, and lingual surfaces.

[0268] The lateral surfaces are connected to each other, forming the crown neck. The lower region of the crown neck forms the crown margin or crown rim.

[0269] A dental composite crown has an outer surface and an inner surface. The inner surface is the surface that is attached to the prepared dental tooth.

[0270] The crown wall thickness at the crown neck (at a distance of 1 mm from the crown margin) is in the range of 0.8 mm or less, or 0.7 mm or less, or 0.6 mm or less, or 0.1 mm to 0.8 mm, or 0.1 mm to 0.7 mm, or 0.1 mm to 0.6 mm, or 0.1 mm to 0.5 mm.

[0271] The wall thickness of the upper surface (occlusal and / or distal) of a preformed crown is typically in the range of 0.15 mm to 1.5 mm, or 0.4 mm to 1.0 mm.

[0272] At least two of the opposing sides and hanging surfaces of a dental composite crown may have a concave shape, preferably the buccal and lingual sides. That is, the side walls of the crown may have a curved shape and thus provide an undercut in the crown neck region.

[0273] The lateral wall thickness of the crown is typically 0.7 mm, 0.6 mm, 0.5 mm, or 0.4 mm or less.

[0274] According to one embodiment, the side wall thickness of the preformed crown is in the range of 0.1 mm to 0.7 mm. According to another embodiment, the side wall thickness of the preformed crown is in the range of 0.1 mm to 0.6 mm. According to yet another embodiment, the side wall thickness of the preformed crown is in the range of 0.1 mm to 0.5 mm. According to a further embodiment, the side wall thickness of the preformed crown is in the range of 0.1 mm to 0.4 mm.

[0275] The present invention also aims to provide three-dimensional articles described herein, preferably for use in methods of restoring or treating teeth in a patient's mouth.

[0276] This method includes, for example, providing a three-dimensional article having the shape of a dental restoration (particularly a dental crown or bridge) as described herein, and fixing the three-dimensional article to the surface of a tooth to be treated or restored by using dental cement.

[0277] The surface of a three-dimensional article, primarily composed of cured (meth)acrylate components and fillers, is typically quite hydrophobic.

[0278] Dental articles that have a crown shape and contain hardened (meth)acrylate components and fillers are often called "dental composite crowns."

[0279] Fixing a three-dimensional object with a hydrophobic surface to a fairly hydrophilic surface (e.g., the surface of hard dental tissue) is not a simple matter.

[0280] The fixation of dental composite crowns typically requires additional steps, such as surface roughening of the tooth and / or inner surface of the dental composite crown, to provide a retaining element for the dental cement.

[0281] Alternatively, or in addition, so-called self-etching dental adhesives may be used, which contain components that can interact with the surface of the composite crown on the one hand and with the surface of the tooth on the other.

[0282] Using the three-dimensional articles described herein, the surface of the three-dimensional article has particles embedded within it, which can simplify the fixation process to facilitate the fixation process.

[0283] The particles may either act as retaining elements or / or chemically interact with reactive components present in the dental cement.

[0284] In general, different cement fixation techniques are available for the fixation of dental crowns and bridges.

[0285] These can be divided into groups such as temporary cement fixation (e.g., RelyX® TempNE / E, 3M Oral Care), conventional cement fixation (e.g., Ketac® CEM or Ketac® CEM Plus, 3M Oral Care), self-adhesive resin cement fixation (e.g., RelyX® Unicem, 3M Oral Care), or adhesive resin cement fixation (e.g., RelyX® Ultimate, 3M Oral Care).

[0286] Generally, cement fixation needs to be durable over the service life of the adaptation, which can be achieved by either chemical bonding, mechanical retention, or a combination thereof.

[0287] Therefore, the choice of cement to be used for a specific application, or the general cement fixing technique, is influenced by the restoration material, the application itself, and the preparation technique, but cost and aesthetics also play a role.

[0288] For pre-formed crowns, such as those used in pediatric dentition, a quick and easy chairside workflow is desired, and a fast and easy cementation technique is preferred. In this regard, different types of dental cements can be used.

[0289] Suitable dental cements include glass ionomer cement (GIZ), resin-modified glass ionomer cement (RM-GIZ), adhesive resin cement, self-adhesive resin cement, and temporary cement.

[0290] Glass ionomer cement is typically supplied as a parts kit containing both liquid and powder components. The two components must be mixed before use.

[0291] Powdered parts typically contain acid-reactive inorganic fillers (e.g., fluoroaluminosilicate glass, FAS glass).

[0292] The liquid component typically comprises a polyacid, water, and a complexing agent (e.g., tartaric acid).

[0293] Glass ionomer cement is commercially available (e.g., Ketac® Cem; 3M Oral Care).

[0294] Glass ionomer cement may also be supplied as a parts kit, including two pastes A and B that are mixed before use.

[0295] Resin-modified glass ionomer cement typically contains the following components: acid-reactive filler, polyacid, water, complexing agent, radiation-curable component, and initiator.

[0296] Suitable radiation-curable components typically contain a (meth)acrylate moiety.

[0297] Resin-modified glass ionomer cement is available in either powder / liquid or paste / paste form, and also as a parts kit.

[0298] The powder components typically include an acid-reactive inorganic filler (e.g., fluoroaluminosilicate glass, FAS glass) and an initiator component.

[0299] The liquid component typically contains a polyacid, water, (meth)acrylate, and an initiator component.

[0300] Resin-modified glass ionomer cements are commercially available (e.g., Ketac® Cem Plus; 3M Oral Care).

[0301] Self-adhesive resin cements typically contain acidic (meth)acrylate monomers, non-acidic (meth)acrylate monomers, fillers (including acid-reactive fillers), initiators, stabilizers, and solvents.

[0302] Adhesive resin cements are also commercially available (for example, RelyX® Ultimate Adhesive Resin Cement; 3M Oral Care).

[0303] This invention can also be used as individual parts: At least one three-dimensional article described herein, in particular a three-dimensional article having the shape of a dental restoration (e.g., a dental crown or dental bridge), The aim is also to provide kits of parts that include dental cement, particularly glass ionomer cement or resin-modified glass ionomer cement.

[0304] Such kits are particularly useful in methods for restoring or treating teeth.

[0305] The present invention also aims to provide a kit or system of parts for manufacturing the surface-modified three-dimensional articles described herein, the kit or system of parts as individual parts: The radiation-curable compositions described herein, Particles for treating the surface of a three-dimensional article as described herein, This specification includes an additive manufacturing apparatus for processing a radiation-curable composition described herein to obtain a three-dimensional article.

[0306] A useful additive manufacturing apparatus includes a 3D printing device (particularly an SLA or DLP printer), a build platform, bottles or cartridges for storing and / or delivering radiation-curable compositions, and instructions for use to describe the process steps outlined herein.

[0307] Further exemplary embodiments of the present invention are shown below.

[0308] Embodiment 1 A three-dimensional article having the shape of a dental restoration (e.g., a crown or bridge) for use in a method of restoring or treating teeth in a patient's mouth, A three-dimensional article has an outer surface and an inner surface, the inner surface containing partially embedded particles, The partially embedded particles have an average particle size in the range of 1 μm to 100 μm. Selected from glass particles, metal oxides or hydroxide particles, or a combination thereof, or containing thereof, The method is The process of providing a 3D object, The process includes fixing a three-dimensional object to the surface of a tooth using dental cement, A three-dimensional article comprising dental cement selected from or including glass ionomer cement, resin cement, adhesive cement, self-adhesive cement, resin-modified glass ionomer cement, or temporary cement.

[0309] Embodiment 2 It is a process, a) A step of providing a radiation-curable composition, b) A step of building up a three-dimensional article by radiation-curing a radiation-curable composition layer by layer, preferably by using stereolithography or digital light processing, c) A step of partially removing a radiation-curable composition adhering to the surface of a three-dimensional article, d) A step of treating at least a portion of the surface of a three-dimensional article to which a radiation-curable composition is attached with particles, e) A step of applying an additional curing step to a three-dimensional article, preferably by applying heat and / or radiation, A radiation-hardening composition (Meth)acrylate components, photoinitiators, fillers, and optionally dyes, wherein the fillers do not contain particles larger than 5 μm in size. At 23℃, 1 mPa * s~100mPa * Having a viscosity in the range of s, The particles used in the processing step are Having an average particle size in the range of 1 μm to 100 μm, Selected from glass powder, metal oxide, or hydroxide powder, and mixtures thereof, A process in which the x, y, and z dimensions of a 3D object are less than 100 mm for each dimension.

[0310] Figure 1 shows a schematic diagram of the process described herein that results in a surface-modified 3D-printed three-dimensional article.

[0311] In Section 1, the surface is shown consisting of two regions: a light gray region and a dark gray region.

[0312] The light gray areas represent the surface portion of the fully cured composition (e.g., containing cured (meth)acrylate components). The fully cured composition may be part of a dental composite crown.

[0313] The dark gray areas represent surface portions of radiation-curable compositions (e.g., those containing (meth)acrylate components) that have not yet cured and are adhering to the surface of fully cured compositions.

[0314] The particles shown on the left side of Section 1 are applied to the dark light region (for example, by using a gas stream or by dropping the particles onto a surface).

[0315] In Section 2, the particles are partially embedded in the radiation-hardening composition (dark gray area).

[0316] Section 3 shows the surface area after the curing process has been applied, with partially embedded particles. The previously dark gray area has become light gray.

[0317] Radiation-curable compositions intended for use in the manufacture of dental or orthodontic articles must not contain any components that are harmful to the patient's health.

[0318] Radiation-curable compositions typically do not contain components that can dissolve particles applied to the surface of a three-dimensional article, such as strong acids (e.g., hydrochloric acid, sulfuric acid, phosphoric acid).

[0319] Furthermore, radiation-curable compositions typically do not contain epoxy resins.

[0320] The curable compositions described herein, and in particular the components used in the manufacture of dental articles, must be sufficiently biocompatible; that is, the compositions must not cause toxic, adverse, or immune reactions in living tissues.

[0321] All disclosures of patents, patent documents, and publications cited herein are incorporated by reference as if each were incorporated individually. Various modifications and changes to the present invention will be apparent to those skilled in the art without departing from the scope and spirit of the invention. The above specification, examples, and data provide a description of the preparation and use of the compositions of the present invention and the methods thereof. The present invention is not limited to the embodiments disclosed herein. Those skilled in the art will recognize that many alternative embodiments of the present invention can be made without departing from the spirit and scope of the invention. The present invention encompasses the following aspects. (1) A process for manufacturing a surface-modified three-dimensional article, wherein the process is A step of providing a radiation-curable composition, The process involves building up a three-dimensional article by radiation-curing the radiation-curable composition layer by layer, preferably using stereolithography or a digital light processing unit. A step of partially removing a radiation-curable composition adhering to the surface of the three-dimensional article, wherein the remaining radiation-curable composition forms a layer on the surface of the three-dimensional article. A step of treating only a portion of the surface of the three-dimensional article to which the radiation-curable composition is attached with particles such that at least a portion of the particles are partially embedded in the radiation-curable composition remaining on the surface of the three-dimensional article, The process includes, preferably, applying an additional curing step to the three-dimensional article by applying heat and / or radiation, A process in which the processing step is adjusted to achieve a surface roughness Ra of 1 μm to 20 μm. (2) The process according to item 1, wherein the thickness of the layer formed by the remaining radiation-curable composition is in the range of 1 μm to 500 μm. (3) The additional curing step has the following characteristics: Applying radiation having wavelengths of 350 nm to 450 nm, and / or Apply a heating process between 30°C and 120°C. The processes described in item 1 or 2, characterized by either one or a combination thereof. (4) The particles have the following characteristics: a) The average particle size is 1 μm to 150 μm. b) Density is 2 g / cm³ 3 ~6g / cm 3 A process described in any of items 1-3, characterized by being, alone or in combination with, being. (5) The process according to any one of items 1 to 4, wherein the material of the particles is selected from glass powder, metal oxide, or hydroxide powder, and mixtures thereof. (6) The radiation-curable composition has the following characteristics: a) Viscosity at 23°C and 1s -1 At a shear rate of 1 Pa * s~400Pa * Being s, b) comprising (meth)acrylate components, photoinitiators, optionally dyes, and optionally fillers, A process described in any of items 1-5, characterized by one or a combination of the above. (7) The processing steps are as follows: a) A step of applying the particles in a gas flow, preferably at an operating pressure in the range of 0.5 kPa to 500 kPa and / or at a particle flow rate in the range of 0.01 g / to 10 g / second. b) A step of applying the particles by coating, The process described in any of items 1-6, including either one or a combination thereof. (8) The partial removal of the radiation-curable composition is carried out in the following process steps: a) A step of moving the three-dimensional object, preferably rotating the three-dimensional object, thereby generating a mass inertial force. b) Steps using the cleaning composition, c) A step of storing the three-dimensional article for a sufficient amount of time to allow the radiation-curable composition to fall off or flow from the surface of the three-dimensional article. d) Steps to apply gas flow, The process described in any of items 1-7, which is carried out by applying either one or a combination of the above. (9) The above process is as follows: The radiation-curable composition is The material comprises a (meth)acrylate component, a photoinitiator, a filler, and optionally a dye, wherein the filler preferably does not contain particles having a size greater than 1 μm. 23℃ and 1s -1 At a shear rate of 5 Pa * s~100Pa * Having a viscosity in the range of s, The particles used in the processing step described above are It has an average particle size in the range of 1 μm to 150 μm. Selected from glass powder, metal oxide powder, hydroxide powder, and mixtures thereof, The x, y, and z dimensions of the aforementioned three-dimensional article are in the range of 1 mm to 100 mm for each dimension. A process described in any of items 1-8, characterized by the above. (10) A three-dimensional article obtained or obtainable by any of the processes described in items 1 to 9. (11) A three-dimensional article according to item 10, having the shape of a dental or orthodontic article, wherein the dental or orthodontic article preferably has an outer surface and an inner surface. (12) The three-dimensional article according to item 11, wherein the three-dimensional article has the shape of a dental restoration having an outer surface and an inner surface, and the inner surface includes partially embedded particles. (13) For use in restoring or treating teeth in a patient's mouth, The method described above is The process of providing the three-dimensional article, The three-dimensional article according to item 11 or 12, comprising the step of fixing the three-dimensional article to the surface of the tooth to be treated or restored by using dental cement, particularly glass ionomer cement, resin-modified glass ionomer cement, resin cement, adhesive cement, self-adhesive cement, or temporary cement. (14) A kit of parts, and the individual parts At least one three-dimensional article as described in any of items 11-13, A kit of parts including dental cement, particularly glass ionomer cement, resin cement, adhesive cement, self-adhesive cement, resin-modified glass ionomer cement, or temporary cement. (15) A kit or system of parts for manufacturing a surface-modified three-dimensional article, wherein the individual parts are Radiation-hardening composition and Particles and Includes an additive manufacturing device, A kit or system of parts, wherein the radiation-curable composition, the particles, and the additive manufacturing apparatus are as described in any of items 1 to 14.

[0322] The following examples are given to illustrate the present invention. [Examples]

[0323] Unless otherwise specified, all parts and percentages are based on weight, all water is deionized water, and all molecular weights are weight-average molecular weights. Furthermore, unless otherwise specified, all experiments were conducted under ambient conditions (23°C, 10¹³ mbar).

[0324] method viscosity If desired, viscosity can be measured at 23°C under a controlled shear rate using a Physica MCR301 rheometer (Anton Paar, Graz, Austria) with a plate / plate configuration. The diameter is 15 mm, and the separation gap between plates is 0.5 mm. The shear rate is 1,000 s. -1 ~0.001s -1 It will rise to that point.

[0325] Particle size (suitable for micro-sized particles) If desired, the particle size distribution, including the average particle size, can be determined using a Cilas 1064 (FA.Quantacrome) particle size detector. During measurement, the sample is typically dispersed accurately using ultrasound.

[0326] Particle size (suitable for nano-sized particles) If desired, particle size measurements can be performed using a light scattering type particle size analyzer with a red laser wavelength of 633 nm (available from Malvern Instruments Inc., Westborough, MA, under the trade name "ZETA SIZER-Nano Series, Model ZEN3600"). Each sample is analyzed in a 1 square centimeter polystyrene sample cuvette. The sample is diluted 1:100; for example, 1 g of sample is added to 100 g of deionized water and mixed. Approximately 1 gram of the diluted sample is filled into the sample cuvette. The sample cuvette is then placed in the apparatus and equilibrated at 25°C. The apparatus parameters are set as follows: refractive index of the dispersant 1.330, viscosity of the dispersant 0.8872 mPa. *The material has a refractive index of 1.43 and an adsorption value of 0.00 units. Next, the automated particle size measurement procedure is performed. The instrument automatically adjusts the laser beam position and attenuator settings to obtain the best possible particle size measurement.

[0327] Light scattering particle size analyzers irradiate a sample with a laser and analyze the intensity fluctuations of the light scattered from the particles at a 173-degree angle. To calculate particle size, the instrumental photon correlation spectroscopy (PCS) method can be used. PCS uses the fluctuating light intensity to measure the Brownian motion of particles in a liquid. The particle size is then calculated as the diameter of a sphere moving at the measured velocity.

[0328] The intensity of light scattered by a particle is proportional to the sixth power of the particle diameter. The Z-mean particle size, or cumulant mean, is an average calculated from the intensity distribution, and the calculation is based on the assumption that the particles are unimodal, monodispersive, and spherical. The relevant functions calculated from the fluctuating light intensity are the intensity distribution and its mean. The mean of the intensity distribution is calculated based on the assumption that the particles are spherical. Both the Z-mean particle size and the mean of the intensity distribution are more sensitive to larger particles than to smaller particles.

[0329] The volume distribution represents the percentage of the total volume of particles corresponding to a given size range. The volume-average particle size is the particle size corresponding to the average of the volume distribution. Since the volume of a particle is proportional to the cube of its diameter, this distribution is less sensitive to larger particles than the Z-average particle size. Therefore, the volume average is typically smaller than the Z-average particle size. Within the scope of this literature, the Z-average size is referred to as the "average particle size."

[0330] pH value If desired, the pH value can be determined as follows: Disperse 1.0 g of the component (e.g., packing material) in 10 mL of deionized water and stir for approximately 5 minutes. Immerse the calibrated pH electrode in the suspension and determine the pH value while stirring.

[0331] elemental composition If desired, the elemental composition can be measured using an X-ray fluorescence spectrometer (XRF), for example, a Rigaku ZSX Primus II. This method is particularly suitable for the analysis of solid materials, such as zirconia ceramics or glass materials.

[0332] Bending strength (FS) If desired, the bending strength can be measured by performing a three-point bending strength test according to ISO 4049:2019 using a test specimen with dimensions of 4*6*25 mm. The bending strength is given in [MPa].

[0333] Modulus of elasticity (EM) If desired, the modulus of elasticity can be determined according to DIN EN843-2:2007 using a test rod with dimensions of 6*4*25 mm (6 mm being the width of the specimen). The modulus of elasticity is determined to be within the range of 20% to 50% of the maximum force applied to the specimen. The modulus of elasticity is given in [GPa].

[0334] Impact strength (IS) If desired, impact strength can be measured according to DIN 53453:1975-05 (Charpy) using a Zwick 5102 pendulum set to 0.5J, with a span of 42mm, using a test specimen having dimensions of 4*6*50mm. Impact strength is [kJ / m 2 It is given by ].

[0335] Shear bond strength (SBS) A stainless steel cylinder with a diameter of 4 mm and a height of 2 mm was surface-roughened (Rocatec® Plus, 3M Deutschland GmbH) and silane-treated (3M ESPE Sil®, 3M Oral Care). The cylinder was cemented onto a substrate using RMGI cement (RelyX® luting plus cement, 3M Deutschland GmbH). This applied cement between the substrate and the cylinder. 240 g was loaded into the cylinder, excess cement was removed, and the load was kept constant for 10 minutes at a temperature of 36°C. The load was removed, and the material was stored for 22 hours at 36°C and 100% relative humidity. SBS is given in MPa.

[0336] For shear bond strength, the substrate was placed in a shearing device and a stainless steel cylinder was sheared at a crosshead speed of 0.75 mm / min. The resulting MPa bond strength was calculated by dividing the shear force [N] by the surface of the cylinder base [mm²]. For each group, n=6 samples were tested.

[0337] Surface roughness (Ra) The surface roughness Ra was determined using a Mahr S2 surface profile analyzer (Mahr GmbH) in accordance with EN ISO 4287:2010-07 and EN ISO 4288:1998-04. Surface roughness is given in μm.

[0338] material [Table 2]

[0339] The compositions outlined in Table 2 were prepared. The amounts of the components are given in parts by weight (pbw) within a preferred range: [Table 3]

[0340] The ingredients were provided and mixed using a kneader to obtain a homogeneous paste.

[0341] Additive manufacturing process: I poured the paste into the work tray of a commercially available DLP printer (Rapidshape, Heimsheim, Germany).

[0342] The pre-processed data (STL file; 3D rectangular object; 25mm x 10mm x 5mm) was loaded into the printer.

[0343] The following printing conditions can be applied: curing light wavelength: 383nm~460nm, curing light intensity: 50W / m 2 ~200W / m 2 Exposure time: 1 to 11 seconds, layer thickness: 50 μm.

[0344] 3D article A three-dimensional article to be surface-treated was manufactured as follows: A composition described in the embodiment of the present invention was prepared. This composition was placed in the vat of an additive manufacturing device. The three-dimensional article was manufactured layer by layer using the parameters described above in the additive manufacturing process. The three-dimensional article had the shape of a rectangular parallelepiped (dimensions: 25 mm × 10 mm × 5 mm). The three-dimensional article was removed from the vat of the additive manufacturing device.

[0345] Cleaning process: Cleaning of the 3D articles from excess material was carried out as described in International Publication No. 2019 / 023120(A1)(3M), using the parameters described in the text above.

[0346] Light curing process For the final curing of 3D articles, 50 mW / cm² 2 ~500mW / cm 2 A photocuring device capable of emitting light in the range of 383nm to 460nn was used.

[0347] Photocuring to completely harden the sample was performed under reduced pressure (in the range of 1 mbar to 100 mbar).

[0348] Process for surface modification The following process parameters were used for sandblasting the surface of a 3D object.

[0349] Processing parameters: Device: Renfert Basic Quattro, Pressure: 2.0 bar ~ 4.0 bar

[0350] Sandblasting process 1: The rectangular specimens, printed and cleaned as described, are sandblasted using the parameters described above before the final photocuring process.

[0351] Sandblasting process 2: The rectangular specimens, printed and cleaned as described, are sandblasted using the parameters described above after the final photocuring process. [Table 4]

Claims

1. A process for manufacturing a surface-modified three-dimensional article having the shape of a dental or orthodontic article, wherein the process comprises: A step of providing a radiation-curable composition containing a (meth)acrylate component and a photoinitiator, A process of building up a three-dimensional article by radiation-curing the radiation-curable composition layer by layer using stereolithography or a digital light processing unit, A step of partially removing a radiation-curable composition adhering to the surface of the three-dimensional article, wherein the remaining radiation-curable composition forms a layer on the surface of the three-dimensional article. A step of treating only a portion of the surface of the three-dimensional article to which the radiation-curable composition is attached with particles such that at least a portion of the particles are partially embedded in the radiation-curable composition remaining on the surface of the three-dimensional article, The process includes applying an additional curing step to the three-dimensional article by applying radiation, A process in which the processing step is adjusted to achieve a surface roughness Ra of 1 μm to 20 μm.

2. The process according to claim 1, wherein the three-dimensional article has an outer surface and an inner surface.

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