Photocuring composition, preparation method thereof, three-dimensional printed part and application of three-dimensional printed part

Abstract

The invention provides a photocuring composition, a preparation method thereof, a three-dimensional printed part and application of the three-dimensional printed part, and belongs to the technical field of three-dimensional printing. The photocuring composition comprises the following components in parts by weight: 10-40 parts of acrylic resin; 30 to 70 parts of a reactive diluent; 0.5 to 25 parts of pigment; and 0.2 to 15 parts of a photoinitiator. Wherein the active diluent comprises an oxetane compound.

Description

Technical Field

[0001] This invention relates to the field of 3D printing technology, specifically to a photocurable composition and its preparation method, 3D printed parts and their applications. Background Technology

[0002] The core principle of ultraviolet (UV) light curing 3D inkjet printing technology is: ultraviolet light radiation triggers a photocuring reaction, and the photosensitive inkjet material is formed into droplets and atomized through the printhead. After being sprayed onto the surface of the substrate, it is cured into a film under the action of ultraviolet light, and then a three-dimensional entity is formed by printing layer by layer and stacking layers.

[0003] In recent years, the market has gradually increased its requirements for printing accuracy and performance. However, due to the limitations of the printhead operating conditions, inkjet materials are prone to problems such as printhead clogging, droplet oblique spraying, and poor droplet formation quality.

[0004] Especially in the field of color 3D inkjet printing, the color photosensitive resin used as inkjet material contains pigments and other particles. If the viscosity is too high, the pigments will easily agglomerate after dispersion, and the material will easily solidify, causing the printhead to become clogged. This not only affects the normal operation of the printhead and reduces printing efficiency, but also increases printing costs.

[0005] Currently, the industry commonly uses the method of adding low-viscosity diluents to reduce resin viscosity. However, while these diluents achieve the goal of reducing viscosity, they also significantly reduce the mechanical properties of 3D molded products, thereby affecting printing stability.

[0006] In summary, how to reduce the viscosity of color photosensitive resin, maintain high printing stability, and ensure that 3D molded products have good mechanical properties has become a pressing technical problem to be solved in this field. Summary of the Invention

[0007] To address the aforementioned technical problems, this invention provides a photocurable composition and its preparation method, a three-dimensional printed part and its application, aiming to at least partially solve the above-mentioned technical problems. The specific technical solutions provided by this invention are as follows.

[0008] As a first aspect of the present invention, a photocurable composition is provided, comprising, by weight: 10-40 parts of an acrylic resin; 30-70 parts of an reactive diluent; 0.5-25 parts of a pigment; and 0.2-15 parts of a photoinitiator. The reactive diluent includes oxetane compounds.

[0009] As a second aspect of the present invention, a method for preparing the above-mentioned photocurable composition is provided, comprising: mixing and grinding a pigment and an active diluent to obtain a color paste; adding an acrylic resin and a photoinitiator to the color paste and mixing under yellow light or in a dark room to obtain a photocurable composition.

[0010] As a third aspect of the present invention, a three-dimensional printed part is provided, which is obtained by photocuring the above-described photocurable composition.

[0011] As a fourth aspect of the present invention, an application of the above-mentioned three-dimensional printed parts is provided in aerospace, automotive, precision instruments, jewelry design and manufacturing, art sculpture creation, orthodontic appliances, surgical guides, and bone implants.

[0012] In this embodiment of the invention, by optimizing the proportions and structure of the photocurable composition, the viscosity of the composition is reduced while maintaining the mechanical properties of the 3D printed parts, improving the dispersion performance of the pigments and preventing printer nozzle clogging. The oxobutane compounds in the reactive diluent, with their low viscosity, help to uniformly disperse the pigments, reducing nozzle problems caused by agglomeration. Their high reactivity also allows for synergistic polymerization with acrylic resins, ensuring that the mechanical properties of the parts do not decrease. This composition is suitable for 3D inkjet and other processes, balancing printing smoothness and part strength. It can meet the core requirements of aerospace, medical, and other fields for the precision and reliability of customized parts, improving printing efficiency and reducing production costs. Detailed Implementation

[0013] The embodiments of the present invention will now be described. However, it should be understood that these descriptions are exemplary only and are not intended to limit the scope of the invention. In the following detailed description, numerous specific details are set forth for ease of explanation to provide a full understanding of the embodiments of the invention. However, it will be apparent that one or more embodiments may be practiced without these specific details. Furthermore, descriptions of well-known structures and techniques are omitted in the following description to avoid unnecessarily obscuring the concept of the invention.

[0014] The terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the invention. The terms “comprising,” “including,” etc., as used herein indicate the presence of the stated features, steps, operations, and / or components, but do not exclude the presence or addition of one or more other features, steps, operations, or components.

[0015] All terms used herein (including technical and scientific terms) have the meanings commonly understood by those skilled in the art, unless otherwise defined. It should be noted that the terms used herein are to be interpreted in a manner consistent with the context of this specification, and not in an idealized or overly rigid way.

[0016] When using expressions such as "at least one of A, B and C", they should generally be interpreted in accordance with the meaning that is commonly understood by those skilled in the art (e.g., "a system having at least one of A, B and C" should include, but is not limited to, a system having A alone, a system having B alone, a system having C alone, a system having A and B, a system having A and C, a system having B and C, and / or a system having A, B and C, etc.).

[0017] In this invention, C a -C b The expression indicates that the group has a number of carbon atoms of ab. Unless otherwise specified, this number of carbon atoms generally does not include the number of carbon atoms of the substituents.

[0018] In this invention, the term "alkyl" may include a branched or straight-chain saturated aliphatic monovalent hydrocarbon group having a specified number of carbon atoms. Examples of C1-C5 alkyl groups include: methyl, ethyl, n-propyl, isopropyl, n-butyl, sec-butyl, isobutyl, tert-butyl, n-pentyl, isopentyl, and various isomers thereof.

[0019] In this invention, the term "haloalkyl" may include a branched or straight-chain saturated aliphatic monovalent hydrocarbon group having a specified number of carbon atoms, wherein one or more hydrogen atoms in the hydrocarbon group are substituted with halogen atoms (selected from one or more of fluorine, chlorine, bromine, and iodine). Examples of C1-C5 haloalkyl groups include: fluoromethyl, chloromethyl, bromomethyl, iodomethyl, difluoromethyl, trifluoromethyl, 1-fluoroethyl, 2-fluoroethyl, 1-chloroethyl, 2-chloroethyl, 1,1-difluoroethyl, 2,2,2-trifluoroethyl, 1-fluoropropyl, 2-fluoroisopropyl, 3-chloropropyl, 2-bromoisobutyl, 3-iodotert-butyl, 1-fluoropentyl, 3-chloroisopentyl, and various isomers thereof.

[0020] In this invention, the term "alkoxy" can include branched or straight-chain saturated aliphatic alkoxy groups (i.e., alkyl-O-structures) having a specified number of carbon atoms, wherein the alkyl portion is a branched or straight-chain saturated aliphatic monovalent hydrocarbon group having the corresponding number of carbon atoms. Examples of C1-C5 alkoxy groups include: methoxy, ethoxy, n-propoxy, isopropoxy, n-butoxy, sec-butoxy, isobutoxy, tert-butoxy, n-pentoxy, isopentoxy, neopentoxy, and their various isomers.

[0021] In this invention, the term "hydroxyalkyl" may include a branched or straight-chain saturated aliphatic monovalent hydrocarbon group having a specified number of carbon atoms, wherein one or more hydrogen atoms in the hydrocarbon group are replaced by hydroxyl groups (-OH). Examples of C1-C5 hydroxyalkyl groups include: hydroxymethyl, 1-hydroxyethyl, 2-hydroxyethyl, 1-hydroxy-n-propyl, 2-hydroxyisopropyl, 3-hydroxy-n-propyl, 1-hydroxy-n-butyl, 2-hydroxy-sec-butyl, 3-hydroxyisobutyl, 4-hydroxy-tert-butyl, 1-hydroxypentyl, 3-hydroxyisopentyl, 2,3-dihydroxypropyl, 1,2-dihydroxypentyl, and various isomers thereof.

[0022] Unless otherwise defined, all technical and scientific terms used in this invention have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains; the terminology used in this invention is for the purpose of describing particular embodiments only and is not intended to limit the invention; the terms "comprising" and "having," and any variations thereof, in the specification and claims of this invention are intended to cover non-exclusive inclusion. Unless otherwise stated, the terms used in this invention have the commonly known meanings understood by one of ordinary skill in the art. Unless otherwise stated, the numerical values ​​of the parameters mentioned in this invention can be measured using various measurement methods commonly used in the art (e.g., they can be tested according to the methods given in embodiments of this invention).

[0023] In the process of realizing the concept of this invention, it was found that the photosensitive resin for color UV curing three-dimensional inkjet printing needs to simultaneously meet the requirements of low viscosity (to be compatible with printhead spraying), stable pigment dispersion, and excellent mechanical properties of the parts. However, in the prior art, the pigment-containing resin system is prone to pigment agglomeration and printhead clogging due to excessive viscosity. Conventional reactive diluents reduce viscosity but significantly weaken the mechanical strength of the parts, and it is difficult to balance curing rate and printing stability.

[0024] Based on this, the present invention provides a photocurable composition comprising an acrylic resin, a reactive diluent, a pigment, a photoinitiator, a dispersant, and optional additives. The reactive diluent includes oxetane compounds. The photocurable composition of the present invention optimizes the system's flowability through the low viscosity characteristics of oxetane compounds, and their high reactivity allows for synergistic polymerization with the acrylic resin. This significantly improves the mechanical properties and curing efficiency of the parts while avoiding pigment agglomeration and ensuring smooth printing, thus meeting the requirements of high-precision color 3D inkjet printing.

[0025] As a first aspect of the present invention, a photocurable composition is provided, comprising, by weight: 10-40 parts of an acrylic resin; 30-70 parts of an reactive diluent; 0.5-25 parts of a pigment; and 0.2-15 parts of a photoinitiator. The reactive diluent includes oxetane compounds.

[0026] In this embodiment of the invention, by optimizing the ratio of the photocurable composition and the structure of the reactive diluent, and using oxocyclobutane compounds as the core component of the reactive diluent, the viscosity of the composition is significantly reduced, the uniformity of pigment dispersion is improved, and nozzle clogging is effectively avoided. Furthermore, due to its high reactivity, it synergistically polymerizes with acrylic resins to ensure that the 3D printed parts maintain excellent mechanical properties and meet the high-efficiency and stable molding requirements of processes such as 3D inkjet printing.

[0027] In some embodiments, oxobutane compounds have the structure shown in formula (I):

[0028] Formula (I);

[0029] Wherein, A is selected from any one of hydrogen, hydroxyl, halogen, C1-C5 haloalkyl, C1-C5 alkyl, C1-C5 alkoxy, and C1-C5 hydroxyalkyl;

[0030] n is an integer between 0 and 5.

[0031] For example, A can be selected from hydrogen, hydroxyl, fluorine, chlorine, bromine, iodine; fluoromethyl, chloromethyl, bromomethyl, iodomethyl, difluoromethyl, trifluoromethyl, 1-fluoroethyl, 2-fluoroethyl, 1-chloroethyl, 2-chloroethyl, 1,1-difluoroethyl, 2,2,2-trifluoroethyl, 1-fluoro-n-propyl, 2-fluoroisopropyl, 3-chloro-n-propyl, 2-bromoisobutyl, 3-iodo-tert-butyl, 1-fluoropentyl, 3-chloroisopentyl and their various isomers; methyl, ethyl, n-propyl, isopropyl, n-butyl, sec-butyl, isobutyl, tert-butyl, n-pentyl, isopentyl and their various isomers; methoxy, ethoxy, n-propoxy, isopropoxy, n-butoxy, sec-butoxy, isobutoxy, tert-butoxy, n-pentoxy, isopentoxy, neopentoxy and their various isomers; hydroxymethyl, 1-hydroxyethyl, 2-hydroxyethyl, 1-hydroxyn-propyl, 2-hydroxyisopropyl, 3-hydroxyn-propyl, 1-hydroxyn-butyl, 2-hydroxysec-butyl, 3-hydroxyisobutyl, 4-hydroxytert-butyl, 1-hydroxypentyl, 3-hydroxyisopentyl, 2,3-dihydroxypropyl, 1,2-dihydroxypentyl and their various isomers.

[0032] In some embodiments, A is selected from any one of hydrogen, C1-C5 haloalkyl, C1-C5 alkyl, and C1-C5 alkoxy.

[0033] n is an integer between 0 and 3.

[0034] For example, A may be selected from hydrogen; fluoromethyl, chloromethyl, bromomethyl, iodomethyl, difluoromethyl, trifluoromethyl, 1-fluoroethyl, 2-fluoroethyl, 1-chloroethyl, 2-chloroethyl, 1,1-difluoroethyl, 2,2,2-trifluoroethyl, 1-fluoro-n-propyl, 2-fluoroisopropyl, 3-chloro-n-propyl, 2-bromoisobutyl, 3-iodo-tert-butyl, 1-fluoropentyl, 3-chloroisopentyl and their various isomers; methyl, ethyl, n-propyl, isopropyl, n-butyl, sec-butyl, isobutyl, tert-butyl, pentyl, isopentyl and their various isomers; methoxy, ethoxy, n-propoxy, isopropoxy, n-butoxy, sec-butoxy, isobutoxy, tert-butoxy, pentoxy, isopentoxy, neopentoxy and their various isomers.

[0035] In some embodiments, the oxetane compounds have structures as shown in formulas (I-1) to (I-7):

[0036] Formula (I-1), Formula (I-2),

[0037] Formula (I-3),

[0038] Formula (I-4),

[0039] Formula (I-5),

[0040] Formula (I-6),

[0041] Formula (I-7).

[0042] In some embodiments, the reactive diluent further includes at least one of free radical reactive diluents and other cationic reactive diluents other than oxoheterobutane compounds.

[0043] In some embodiments, the free radical reactive diluent includes monofunctional acrylates, difunctional acrylates, polyfunctional acrylates, vinyl compounds, and vinyl ether compounds.

[0044] For example, the free radical reactive diluent may be selected from cyclotrimethylolpropane methyl acetal acrylate (CTFA), hydroxyethyl methacrylate (HEMA), isobornyl acrylate (IBOA), 2-ethylhexyl acrylate (2-EHA), lauryl acrylate (LA), N-vinylpyrrolidone (NVP), β-carboxyethyl acrylate (BCEA), 1,6-hexanediol diacrylate (HDDA), dipropylene glycol diacrylate (DPGDA), tripropylene glycol diacrylate (TPGDA), tricyclodecanediethanol diacrylate (TCDDA), trimethylolpropane triacrylate (TMPTA), pentaerythritol triacrylate (PETA), di-trimethylolpropane tetraacrylate (DTMPTTA), ethoxylated trimethylolpropane triacrylate (ETPTA), and propoxylated trimethylolpropane triacrylate (PTMPTA).

[0045] In some embodiments, other cationic reactive diluents besides oxadiazon compounds include epoxy compounds, tetrahydrofuran compounds, and oxazolidinone compounds.

[0046] For example, other cationic reactive diluents besides oxadiazon compounds may be selected from 3,4-epoxycyclohexylmethyl-3',4'-epoxycyclohexane carboxylate (TTA21), 1,2-epoxycyclohexane (1,2-ECH), 3-methyltetrahydrofuran (3-MTHF), 1,4-butanediol di(tetrahydrofuranyl) ether (BDBTE), and 3-ethyl-2-oxazolidinone (EOZ).

[0047] In some embodiments, the photocurable composition further includes: 0.1-10 parts of an additive. The additive is selected from at least one of a sensitizer, leveling agent, dispersant, surfactant, defoamer, and storage enhancer.

[0048] Preferably, the photocurable composition comprises, by weight: 10-40 parts of acrylic resin; 30-70 parts of reactive diluent; 0.5-25 parts of pigment; 0.2-15 parts of photoinitiator; and optionally, 0.1-10 parts of additives.

[0049] In some embodiments, the sensitizer can extend the UV absorption range of the photoinitiator, improve the photosensitive response efficiency, adapt to UV-LED light sources, reduce curing energy requirements, shorten curing time, and without affecting the low viscosity of the photocurable composition and the mechanical properties of the parts.

[0050] For example, the sensitizer may be selected from 2-isopropylxanthoxanone (IX), 2-chloroxanthoxanone (CX), 2,3-dichloroanthraquinone (DCAQ), 1-chloroanthraquinone (CAQ), ethyl 4-dimethylaminocinnamate (EDAB), and isooctyl p-dimethylaminobenzoate (EHA).

[0051] In some embodiments, the leveling agent can reduce the surface tension of the photocurable composition, promote the uniform spreading of printing droplets, eliminate surface defects such as pinholes and orange peel, and has excellent compatibility with the system, without affecting the viscosity and mechanical properties of the part, thus ensuring the accuracy of the 3D printed appearance.

[0052] For example, the leveling agent is selected from at least one of silicone leveling agents, acrylic leveling agents, and fluorinated leveling agents. Silicone leveling agents include polyether-modified polysiloxane (BYK-333), polyester-modified polysiloxane (BYK-310), and alkyl-modified polysiloxane (BYK-322); acrylic leveling agents include acrylate copolymers (BYK-358N) and fluorinated acrylate copolymers (BYK-361N); and fluorinated leveling agents include perfluoropolyether-modified leveling agents (BYK-348) and fluoroalkyl-modified polysiloxanes (EFKA-3600).

[0053] In some embodiments, the dispersant can effectively improve the dispersion of each component in the photocurable composition, prevent sedimentation or agglomeration, and make the components more evenly distributed.

[0054] For example, the dispersant is selected from at least one of polyether block copolymers, polyurethane block copolymers, polyester block copolymers, marinic acid block copolymers, acrylic block copolymers, and organically modified polysiloxanes. Specifically, the dispersant may be Lubrizol Solsperse 36000, Lubrizol Solsperse 32000, Degussa Disperse 685, Degussa Disperse 655, BYK Disperbyk 2200, or BYK Disperbyk 2205.

[0055] In some embodiments, surfactants can improve the compatibility and dispersion stability of pigments and acrylic resins in the photocurable composition, reduce the surface tension of the system, assist in leveling, prevent pigment agglomeration and surface pinholes, and do not affect the viscosity of the system or the curing reaction, thus ensuring smooth printing and the appearance accuracy of the parts.

[0056] For example, the surfactant may be selected from polyoxyethylene octylphenyl ether (OP-10), polyoxyethylene nonylphenyl ether (NP-10), polyoxyethylene sorbitan monolaurate (Tween-20), polyoxyethylene sorbitan monooleate (Tween-80), lauryl polyoxyethylene ether (AEO-9), and cetyl polyoxyethylene ether (C16-18 AEO-12).

[0057] In some embodiments, the defoamer can quickly break up the bubbles generated during the preparation and printing of the photocurable composition, inhibit bubble regeneration, avoid defects such as pinholes and pits in the parts, and has excellent compatibility with the system, without affecting viscosity, curing efficiency and mechanical properties of the parts, thus ensuring printing stability.

[0058] For example, the defoamer is selected from at least one of silicone defoamers, polymer defoamers, and mineral oil defoamers. Preferably, the defoamer specifically includes one or more of BYK017, BYK018, BYK019, BYK021, BYK022, BYK023, BYK024, BYK025, BYK026, BYK044, BYK065, BYK066, BYK077, BYK088, BYK094, BYK011, BYK012, BYK015, BYK016, BYK052, BYK055, BYK057, BYK035, BYK037, BYK038, and BYK039.

[0059] In some embodiments, the storage enhancer can inhibit self-polymerization, oxidation and yellowing of the photocurable composition during storage, maintain the viscosity and pigment dispersion stability of the system, avoid performance degradation during storage, and not affect the subsequent photocuring efficiency and mechanical properties of the parts, thereby extending the shelf life of the photocurable composition.

[0060] For example, the storage enhancer is selected from at least one of polymerization inhibitors, antioxidants, and ultraviolet absorbers. The polymerization inhibitor may be selected from p-methoxyphenol (MEHQ), hydroquinone (HQ), tert-butylhydroquinone (TBC), p-benzoquinone (BQ), methylhydroquinone (MHQ), diphenylamine (DPA), and phenyl-β-naphthylamine (PBN). The antioxidant may be selected from 2,6-di-tert-butyl-4-methylphenol (BHT), pentaerythritol tetrakis[β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate] (1010), tris(2,4-di-tert-butylphenyl) phosphite (168), and triphenyl phosphite (TPP). The ultraviolet absorber can be selected from 2-(2'-hydroxy-5'-methylphenyl)benzotriazole (UV-P), 2-(2'-hydroxy-3',5'-di-tert-butylphenyl)benzotriazole (UV-327), 2,4-dihydroxybenzophenone (UV-0), and 2-hydroxy-4-methoxybenzophenone (UV-9).

[0061] In some embodiments, the acrylic resin is selected from at least one of polyurethane acrylic resin, epoxy acrylic resin, and polyester acrylic resin, preferably aliphatic polyurethane acrylic resin. The polyurethane acrylic resin may be one or more of CN8881NS, CN9001NS, CN 8887NS, CN8888NS, CN9021NS, CN9167, CN9782, CN959, CN964NS, CN980NS, CN981NS, CN983NS, CN9245, CN989NS, CN8000NS, CN9010NS, and CN9013NS manufactured by Sartomer. The epoxy acrylic resin may be one or more of CN115 NS, CN120 N, CN120C80, and CN2003 manufactured by Sartomer. The polyester acrylic resin may be one or more of CN2254NS, CN2303, and CN299 manufactured by Sartomer.

[0062] In some embodiments, the pigment is selected from at least one of organic pigments and inorganic pigments. The pigments of the present invention, as colorants, have no special requirements and can be selected from the prior art.

[0063] In some embodiments, the pigment is 0.5-25 parts by weight, such as 1.2 parts, 1.8 parts, 2.5 parts, 3.5 parts, 4.5 parts, 5.5 parts, 6.5 parts, 7.5 parts, 8.5 parts, 10 parts, 12 parts, 14 parts, 16 parts, or 18 parts. Preferably, it is 2-15 parts, which can better balance the color and curing performance of the photocurable composition.

[0064] The pigments mentioned above can be any color, such as black, blue, brown, cyan, green, white, purple, magenta, red, orange, and yellow, as well as spot colors of their mixtures.

[0065] For example, organic pigments are selected from one or more of the following: phthalocyanine pigments (e.g., phthalocyanine green, phthalocyanine blue), cyanine pigments (e.g., Cy3, Cy5, and Cy7), naphthalene phthalocyanine pigments, nitroso pigments, azo pigments, diazo pigments, diazo condensation pigments, basic dye pigments, basic blue pigments, indigo pigments, root bark red pigments, quinacridone pigments, isoindolinone pigments, dioxazine pigments, carbazolium dioxazine violet pigments, alizarin lake pigments, phthalamide pigments, carmine lake pigments, tetrachloroisoindolinone pigments, violet ketone pigments, anthraquinone pigments, and quinophthalone pigments. Inorganic pigments are selected from one or more of the following: titanium oxides (e.g., titanium dioxide, conductive titanium dioxide), iron oxides (e.g., red iron oxide, yellow iron oxide, black iron oxide, and transparent iron oxide), aluminum oxides, silicon oxides, carbon black pigments, metal sulfides, and metal chlorides.

[0066] In some embodiments, the photoinitiator is selected from at least one cationic photoinitiator and at least one radical photoinitiator. The present invention does not impose any particular limitation on the type of photoinitiator. The cationic photoinitiator is preferably 0.1-10 parts by weight, more preferably 0.5-5 parts by weight. The radical photoinitiator is preferably 0.1-10 parts by weight, more preferably 0.5-5 parts by weight.

[0067] For example, the cationic photoinitiator is selected from at least one of iodonium salt cationic photoinitiators, thionium salt cationic photoinitiators, and arylferrocene salt cationic photoinitiators.

[0068] More preferably, the anionic moiety of the above-mentioned iodonium salt and thionium salt photoinitiator can be: Cl - ,Br - PF6 - SbF6 - AsF6 - BF4 - C4F9SO3-, B(C6H5)4-, C8F 17 SO3-, CF3SO3 - Al[OC(CF3)3]4 - (CF3CF2)2PF4 - (CF3CF2)3PF3 - [(CF3)2CF2]2PF4 - [(CF3)2CF2]3PF3 - [(CF3)2CFCF2]2PF4 - (CF3)2CFCF2]3PF3 - For example, thioonium salt cationic photoinitiators include triarylhexafluoroantimony thioonium salt (PAG201).

[0069] Commercially available cationic photoinitiators with similar structures can also be used in the photocurable compositions of the present invention, such as (but not limited to): PAG201, PAG202, PAG30201, PAG30101, etc. produced by Changzhou Qiangli Electronic New Materials Co., Ltd., and Irgacure250, etc. produced by BASF GmbH, Germany.

[0070] For example, free radical photoinitiators may include 1-hydroxycyclohexylphenyl ketone (184), benzophenone-based free radical photoinitiators such as benzophenone, alkyl-substituted benzophenone, alkoxy-substituted benzophenone, benzoin-based free radical photoinitiators (e.g., benzoin, benzoin ethers (e.g., benzoin methyl ether, benzoin ethyl ether, benzoin isopropyl ether, benzoin phenyl ether), benzoin acetate), acetophenone-based free radical photoinitiators (e.g., acetophenone, 2,2-dimethoxyacetophenone, 4-(phenylthio)acetophenone and 1,1-dichloroacetophenone), benzoin, benzoin ketal (e.g., benzoin dimethyl ketal and benzoin diethyl ketal), anthraquinone-based free radical photoinitiators (e.g., 2-methylanthraquinone, 2-ethylanthraquinone, 2-tert-butylanthraquinone, 1-chloroanthraquinone and 2-ethylanthraquinone), and 2-methylanthraquinone, 2-ethylanthraquinone, 2-tert-butylanthraquinone, 1-chloroanthraquinone and 2-ethylanthraquinone), benzoin, benzoin ketal (e.g., benzoin dimethyl ketal and benzoin diethyl ketal), and anthraquinone-based free radical photoinitiators (e.g., 2-methylanthraquinone, 2-ethylanthraquinone, 2-tert-butylanthraquinone, 1-chloroanthraquinone and 2-ethylanthraquinone), benzoin, benzoin ketal (e.g., benzoin dimethyl ketal and benzoin diethyl ketal), benzoin ketal (e.g., 2-methylanthraquinone, 2-ethyl -Pentylanthraquinone), triphenylphosphine, benzoylphosphine oxide radical photoinitiators (e.g., 2,4,6-trimethylbenzoyldiphenylphosphine oxide), thioxanone, tonone, acridine derivatives, phenazine derivatives, quinoline derivatives, 1-phenyl-1,2-propanedione-2-O-benzoyl oxime, 1-aminobenzophenone radical photoinitiators, 1-hydroxybenzophenone radical photoinitiators (e.g., 1-hydroxycyclohexylphenyl ketone, phenyl(1-hydroxyisopropyl) ketone, 4-isopropylphenyl(1-hydroxyisopropyl) ketone), triazine compound radical photoinitiators (e.g., 4′″-methylthiophenyl-1-di(trichloromethyl)-3,5-S-triazine, S-triazine-2-(stilbene)-4,6-bis(dichloromethyl) and p-methoxystyryltriazine).

[0071] As a second aspect of the present invention, a method for preparing the above-mentioned photocurable composition is provided, comprising: mixing and grinding a pigment and an active diluent to obtain a color paste; adding an acrylic resin and a photoinitiator to the color paste and mixing under yellow light or in a dark room to obtain a photocurable composition.

[0072] In this embodiment of the invention, a uniform color paste is formed by pre-grinding the pigment and reactive diluent, effectively ensuring the stability of pigment dispersion; a yellow light or dark room environment can prevent premature activation of the photoinitiator, prevent self-aggregation of the system, and ensure the stability of the composition during storage and use. The resulting photocurable composition has a viscosity suitable for the requirements of 3D inkjet printing, and the cured part has a smooth surface, uniform color, and no defects, with excellent mechanical properties, combining the technical advantages of high-efficiency production and stable quality.

[0073] Specifically, when an additive is added to the photocurable composition, the preparation method is as follows.

[0074] Step 1: Mix the pigment, reactive diluent, and first additive, and add zirconium beads to a grinder. Grind and mix the ingredients in the grinder to obtain a color paste. The first additive includes at least one of a dispersant and a storage enhancer. Grinding refines the pigment particle size, resulting in a more uniform color distribution of the photocurable composition during inkjet printing. Optionally, the maximum particle size of the ground pigment is less than 1 μm. In some embodiments, the quality of the color paste can be improved by filtering the ground color paste to remove excessively large pigment particles and other impurities.

[0075] Step 2: Mix the acrylate resin, photoinitiator, and second additive with the color paste under yellow light or in a dark room, and stir until homogeneous to obtain a photocurable composition. The second additive includes at least one of a sensitizer, defoamer, leveling agent, and surfactant.

[0076] As a third aspect of the present invention, a three-dimensional printed part is provided, which is obtained by photocuring the above-described photocurable composition.

[0077] In some embodiments, the photopolymerization molding process includes any one of three-dimensional inkjet printing and stereolithography. Optionally, other rapid prototyping technologies, such as digital light processing, continuous liquid interface manufacturing, two-photon polymerization, and polymer jetting, may also be used, and the present invention is not limited thereto.

[0078] In some embodiments, the electromagnetic radiation used for curing in the preparation process is selected from any one of ultraviolet light, visible light, and laser beam. Considering curing efficiency, ease of operation, and technological maturity, ultraviolet (UV) radiation is the preferred type of electromagnetic radiation.

[0079] In 3D inkjet printing, a photocurable composition can be precisely applied to the target area of ​​a substrate in the form of continuous droplets using an inkjet printhead such as a piezoelectric inkjet printhead. The applied liquid photocurable composition is then exposed to electromagnetic radiation for radiation curing, causing the photocurable composition to rapidly cross-link and solidify, ultimately creating a 3D printed part with the desired shape. The substrate can be selected from a variety of materials, including paper, fabric, ceramic tile, printing plate, wallpaper, plastic, and paste.

[0080] As a fourth aspect of the present invention, an application of the above-mentioned three-dimensional printed parts is provided in aerospace, automotive, precision instruments, jewelry design and manufacturing, art sculpture creation, orthodontic appliances, surgical guides, and bone implants.

[0081] In summary, the core objective of this invention is to provide a photocurable composition and its preparation method, a 3D printed part and its application, aiming to solve the technical problem of high viscosity of color photosensitive resin in the prior art, which easily causes printer nozzle clogging, and simultaneously improve pigment dispersion performance. Its beneficial effects are reflected in that, by optimizing the formulation and structural design of the photocurable composition, while ensuring that the mechanical properties of the 3D printed part are not reduced, the viscosity of the photocurable composition system is effectively reduced, and the pigment dispersion stability is improved, thereby completely avoiding the nozzle clogging problem and adapting to the process requirements of 3D inkjet printing.

[0082] The present invention will be described in more detail below through embodiments, but the present invention is not limited to the following embodiments. In the following description, unless otherwise stated, "%" means "mass %" and "parts" means parts by mass.

[0083] Examples 1-5 and Comparative Examples 1-3

[0084] The embodiments and comparative examples of the present invention provide a photocurable composition for three-dimensional inkjet printing. The specific components and corresponding weight parts of the photocurable composition in each embodiment and comparative example are detailed in Table 1.

[0085] Table 1

[0086]

[0087] A1-A5: Prepared according to the preparation method in Chinese Patent Application No. CN202510339486.X, wherein A1-A5 are respectively oxobutane compounds represented by formulas (I-1)-(I-5).

[0088] CTFA: Cyclotrimethylolpropane methyl acetal acrylate (Guangdong Lankeluo New Materials Co., Ltd.);

[0089] TTA21: 3,4-epoxycyclohexylmethyl-3',4'-epoxycyclohexane carboxylate (Jiangsu Taiter New Material Technology Co., Ltd.);

[0090] PETA: Pentaerythritol triacrylate (Changzhou Taihan Chemical Technology Co., Ltd.);

[0091] HDDA: 1,6-hexanediol diacrylate (Sartoma Chemicals Ltd.);

[0092] CN983NS: Polyurethane acrylate (Sartoma Chemical Co., Ltd.);

[0093] CN9013NS: Polyurethane acrylate (Sartoma Chemical Co., Ltd.);

[0094] PAG201: Triarylhexafluoroantimony sulfonium salt (Changzhou Qiangli Electronic New Materials Co., Ltd.);

[0095] 184: 1-Hydroxy-cyclohexyl-phenyl ketone (Changzhou Qiangli Electronic New Materials Co., Ltd.);

[0096] BYK052: Defoamer (BYK Chemicals Ltd.);

[0097] Solsperse 36000: Dispersant (Lubrizol Specialty Chemicals Manufacturing Co., Ltd.)

[0098] Furthermore, the photocurable composition was prepared according to the components and corresponding weight parts recorded in Table 1 above, and three-dimensional inkjet printing was carried out based on the prepared photocurable composition.

[0099] 1. Preparation of the light-curing composition

[0100] Step 1: Using a disperser, stir the reactive diluent and dispersant at 300 rpm for 30 minutes until the system is uniform. Then add the pigment, adjust the speed to 450 rpm and continue stirring for about 1 hour to initially achieve the pre-dispersion of the pigment.

[0101] Step 2: Use a grinding mill with a zirconia rotor for coarse grinding. The coarse grinding time is controlled to be 1.5 hours to reduce the particle size of pigment agglomerates.

[0102] Step 3: Grind the above material using a grinder with a separator for 2 hours, and then filter it through 1μm PP filter paper to remove large particles of impurities that are not fully dispersed.

[0103] Step 4: Add the remaining components of the photocurable composition to the system after fine grinding and filtration, and stir at high speed of 1500 rpm for 30 minutes in a yellow light chamber until the mixture is uniform. Finally, use a microporous filter membrane with a filtration accuracy of 1-3 μm for terminal filtration to obtain a uniformly dispersed photocurable composition suitable for 3D inkjet printing.

[0104] 2. Inkjet printing

[0105] The photocurable composition is fed into the ink cartridge of the 3D printing experimental machine. The printing model and parameters are established, and printing begins. The printer prints the 2D graphic layer by layer and cures each layer to obtain the 3D color original. Printing parameters: layer thickness 50μm, spacing 50μm, light source 365nm.

[0106] 3. Performance Testing

[0107] The formulation viscosity, flexural strength, tensile strength, heat distortion temperature, and clogging resistance of the photocurable compositions of each embodiment and comparative example were compared and tested, and the results are shown in Table 2.

[0108] (1) Viscosity test was performed using a rotational viscometer (25°C) according to standard ASTM D445.

[0109] (2) The tensile strength and flexural strength were tested in accordance with the standard ASTM D638.

[0110] (3) The heat distortion temperature (HDT) test is conducted in accordance with the standard ASTM D648.

[0111] (4) Clog resistance evaluation: Before printing, test the nozzle for clogging, then print the part, and perform another nozzle test after printing. The printing stability of the photocurable composition is detected by the clogging status of the nozzle.

[0112] The printhead usage of each embodiment and comparative example was observed before and after printing, and the evaluation criteria are as follows:

[0113] A: No nozzle blockage;

[0114] B: There is a problem with the nozzle being clogged.

[0115] (5) Color representation:

[0116] A: The surface color is uniform and glossy, and the pigment dispersion is good;

[0117] B: The surface color is slightly uneven, and the pigment dispersion is poor;

[0118] C: The surface color is obviously uneven, and the pigment dispersion is poor.

[0119] Table 2

[0120]

[0121] The viscosity of 3D inkjet printing ink is usually between 200-2,000 mPa·s (at 25-30℃). Without reducing mechanical properties and printing effect, the lower the viscosity, the less likely it is to clog high-precision printheads, and the more suitable it is for high-resolution inkjet printing.

[0122] As shown in Table 2, the performance of the 3D printed parts prepared in Comparative Examples 1-3 did not fully meet the requirements. While Comparative Example 1 did not experience nozzle clogging, the printed part had low strength and exhibited slight peeling. Although the printed parts in Comparative Examples 2-3 had high hardness, their high viscosity led to reduced color reproduction and nozzle clogging, resulting in poor printing stability.

[0123] The photocurable compositions provided in Examples 1-5 of this invention have suitable viscosity (200-300 mPa·s), and there is no nozzle clogging during printing. The printing results are clear and complete, thus exhibiting good printing stability. Their mechanical properties are relatively good, possessing high hardness and toughness (tensile strength ≥40 MPa, flexural strength ≥80 MPa), and a high heat distortion temperature (HDT ≥60℃), as well as excellent color performance, demonstrating superior overall performance.

[0124] The specific embodiments described above further illustrate the purpose, technical solution, and beneficial effects of the present invention. It should be understood that the above descriptions are merely specific embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A photocurable composition, characterized in that, The photocurable composition comprises, by weight: Acrylic resin, 10-40 parts; Reactive diluent, 30-70 parts; Pigment, 0.5-25 parts; and Photoinitiator, 0.2-15 parts; The active diluent includes oxobutane compounds.

2. The photocurable composition according to claim 1, characterized in that, The oxobutane compounds have the structure shown in formula (I): Equation (I); Wherein, A is selected from any one of hydrogen, hydroxyl, halogen, C1-C5 haloalkyl, C1-C5 alkyl, C1-C5 alkoxy, and C1-C5 hydroxyalkyl; n is an integer between 0 and 5.

3. The photocurable composition according to claim 2, characterized in that, A is selected from any one of hydrogen, C1-C5 haloalkyl, C1-C5 alkyl, and C1-C5 alkoxy. n is an integer between 0 and 3.

4. The photocurable composition according to claim 3, characterized in that, The oxobutane compounds have structures as shown in formulas (I-1) to (I-7): Equation (I-1), Equation (I-2), Equation (I-3), Equation (I-4), Equation (I-5), Equation (I-6), Equation (I-7).

5. The photocurable composition according to claim 1, characterized in that, The reactive diluent also includes at least one of the following: a free radical reactive diluent and a cationic reactive diluent other than the oxobutane compounds; The free radical reactive diluents include monofunctional acrylates, difunctional acrylates, polyfunctional acrylates, vinyl compounds, and vinyl ether compounds. Other cationic reactive diluents besides the oxacyclobutane compounds include epoxy compounds, tetrahydrofuran compounds, and oxazolidinone compounds.

6. The photocurable composition according to claim 1, characterized in that, The photocurable composition further includes: Additives, 0.1-10 parts; The additive is selected from at least one of sensitizers, leveling agents, dispersants, surfactants, defoamers, and storage enhancers.

7. The photocurable composition according to claim 1, characterized in that, The acrylic resin is selected from at least one of polyurethane acrylic resin, epoxy acrylic resin, and polyester acrylic resin; The pigment is selected from at least one of organic pigments and inorganic pigments; The photoinitiator is selected from at least one of cationic photoinitiators and at least one of free radical photoinitiators.

8. A method for preparing a photocurable composition as described in any one of claims 1-7, characterized in that, include: Pigments and reactive diluents are mixed and ground to obtain a color paste; Acrylic resin and photoinitiator are added to the color paste and mixed under yellow light or in a dark room to obtain a photocurable composition.

9. A three-dimensional printed part, characterized in that, The three-dimensional printed part is obtained by photocuring the photocurable composition according to any one of claims 1-7.

10. The three-dimensional printed part according to claim 9, characterized in that, The photopolymerization molding process includes any one of three-dimensional inkjet printing or stereolithography. The electromagnetic radiation used for curing in the preparation process is selected from any one of ultraviolet light, visible light, and laser beam.

11. The application of a three-dimensional printed part as described in claim 9 or 10 in aerospace, automotive, precision instrument, jewelry design and manufacturing, art sculpture creation, orthodontic appliances, surgical guides, and bone implants.

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