A photoinitiator, its preparation method, compositions comprising the same, and their applications.

Abstract

This invention provides a photoinitiator, its preparation method, compositions containing the same, and their applications. By optimizing the structural formula of the photoinitiator, the problems of yellowing and low initiation efficiency of commercially available initiators during photopolymerization can be solved, and the density of the organic-inorganic dual-network structure can be improved, thereby obtaining a high-density dual-network printed composite ceramic crown bridge composition, achieving higher strength, hardness, and molding precision in the product, with broad application prospects.

Description

Technical Field

[0001] This invention relates to the field of dental restoration technology, and more particularly to a photoinitiator, its preparation method, compositions comprising the same, and their applications. Background Technology

[0002] 3D printing technology, as a manufacturing technology with significant digital characteristics, has not only become a link in the digital dental processing chain, but also connects dental diagnosis, design, and production processes through data flow, forming a fully digital process for dental product processing. In recent years, mainstream dental processing plants have been undergoing digital transformation, which has driven the development of 3D printed dental materials.

[0003] 3D-printed composite ceramic materials can be used to fabricate crowns, bridges, veneers, inlays, and other restorations. Due to their low production cost and short production time, they are considered an ideal alternative to CAD / CAM resin-based ceramic materials. 3D-printed composite ceramic materials are typically organic-inorganic composite materials formed by mixing organic resin as the matrix, inorganic ceramic fillers as reinforcements, and adding photoinitiators and other additives.

[0004] Due to the higher content of inorganic fillers, the photo-initiated polymerization in 3D printed composite ceramic materials is less intense compared to the thermally initiated polymerization of CAD / CAM resin-based ceramic materials. This results in a looser organic-inorganic dual-network structure after polymerization, making it easier for water from saliva to enter the organic network. This releases incompletely polymerized resin monomers and some chemical components from the material into the oral environment, leading to risks such as marginal microleakage causing secondary caries, restoration fractures and detachment due to decreased material mechanical properties, reduced molding precision after water absorption leading to decreased wearing comfort, and even decreased resistance to food pigment staining resulting in poor aesthetics.

[0005] Furthermore, commercially available photoinitiators for the 385 / 405nm wavelength band generally contain large conjugated structures (chromophores) to achieve good light absorption. However, when the amount of photoinitiator used is low, the degree of polymerization is low, the organic-inorganic dual-network structure is loose, and the product's strength, hardness, and molding precision are poor. While increasing the amount of photoinitiator improves the density of the dual network, the large conjugated structure leads to poor solubility of the photoinitiator in the monomer, resulting in poor color stability and color difference values ​​that do not meet clinical requirements.

[0006] Therefore, the key to whether 3D printed composite ceramic materials can replace CAD / CAM resin-based ceramic materials lies in how to improve the density of the organic-inorganic dual-network structure while ensuring safety, aesthetics, and comfort. Summary of the Invention

[0007] In view of the shortcomings of the prior art, the present invention aims to provide a photoinitiator, a method for preparing the same, a composition containing the same, and its application. By optimizing the structure of the initiator, the problems of easy yellowing and low initiation efficiency in the prior art are avoided. Furthermore, by compounding the components of the composition, the strength, hardness, and molding precision of the product are improved.

[0008] To achieve this objective, the present invention adopts the following technical solution:

[0009] In a first aspect, the present invention provides a photoinitiator, the structural formula of which is shown in formula (1):

[0010]

[0011] In formula (1), X is a halogen element or hydrogen, R1 and R2 are each independently any one of the substituted and / or substituted phenyl and / or hydrocarbon groups, for example, any one or a combination of at least two of the hydrocarbon groups, tolyl, ethylphenyl, phenyl or propanyl groups with 1 to 15 carbon atoms, wherein the number of carbon atoms can be, for example, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14 or 15, etc., and Y1 and Y2 are each independently a branched or straight-chain hydrocarbon group.

[0012] Compared to existing commercially available photoinitiators, the photoinitiator provided by this invention has an α-carbonyl structure, thus it not only has the advantages of easy compatibility with resin systems and high initiation efficiency, but also, due to the short initiation efficiency of the photoinitiator provided by this invention, it can increase the degree of polymerization reaction, thereby ultimately increasing the density of dental restorative materials; preferably, it does not have a phenyl-phosphorus chemical bond structure, thus it has biocompatibility and can be used as a dental material.

[0013] Preferably, X in formula (1) includes any one of fluorine, bromine, chlorine or iodine, and is preferably fluorine.

[0014] Preferably, R1 and R2 are each independently a substituted and / or substituted phenyl group, preferably p-methylphenyl.

[0015] The present invention preferably uses p-methylphenyl, which has a biosafety effect. That is, after the free radical initiation is completed, benzoic acid and its derivatives are generated, which are easily excreted by the human body and there is no problem of toxic residue. It can be well applied in the field of dental materials.

[0016] Preferably, Y1 and Y2 are each independently an alkane group having 1 to 5 carbon atoms, for example, 1, 2, 3, 4 or 5, preferably methyl.

[0017] In a second aspect, the present invention provides a method for preparing the photoinitiator described in the first aspect, the method comprising:

[0018] Oxaloyl chloride and halobenzene undergo a first reaction to prepare p-halobenzoyl ester; the p-halobenzoyl ester undergoes a second reaction with the structure shown in formula (2) to prepare a photoinitiator of the structure of formula (1).

[0019]

[0020] R3 in formula (2) is an aromatic hydrocarbon group.

[0021] The preparation process provided by this invention can realize the preparation of the photoinitiator in formula (1). The preparation process has the advantages of simple operation and green environmental protection, and has broad application prospects.

[0022] Preferably, the oxaloyl chloride ester is oxaloyl chloride formate.

[0023] Preferably, the p-halobenzoyl ester is a p-halobenzoyl carboxylate.

[0024] Preferably, R3 in the structure shown in formula (2) is any one or a combination of at least two of the substituted phenyl, benzyl or phenethyl.

[0025] Preferably, the mass ratio of oxaloyl chloride to halobenzene is 1.02 to 1.6:1, for example, it can be 1.02:1, 1.09:1, 1.15:1, 1.22:1, 1.28:1, 1.35:1, 1.41:1, 1.48:1, 1.54:1 or 1.6:1, but is not limited to the listed values. Other unlisted values ​​within this range are also applicable.

[0026] Preferably, the mass ratio of the structure shown in formula (2) to the p-halobenzoyl ester is 2.3 to 3.2:1, for example, it can be 2.3:1, 2.4:1, 2.5:1, 2.6:1, 2.7:1, 2.8:1, 2.9:1, 3:1, 3.1:1 or 3.2:1, but is not limited to the listed values. Other unlisted values ​​within this range are also applicable.

[0027] Preferably, the first reaction is carried out under the catalysis of a catalyst.

[0028] Preferably, the catalyst comprises aluminum trichloride.

[0029] Preferably, the mass ratio of aluminum trichloride to halobenzene is 1.4 to 1.75:1, for example, it can be 1.40:1, 1.44:1, 1.48:1, 1.52:1, 1.56:1, 1.6:1, 1.64:1, 1.68:1, 1.72:1 or 1.75:1, but is not limited to the listed values. Other unlisted values ​​within this range are also applicable.

[0030] Preferably, the first reaction comprises: mixing halobenzene, aluminum trichloride, and a first solvent to obtain a first mixture; mixing oxaloyl chloride and a second solvent to obtain a second mixture; and adding the second mixture dropwise to the first mixture while simultaneously stirring to carry out a first stage reaction. After the addition is complete, the temperature is raised and the second stage reaction continues.

[0031] Preferably, the first solvent comprises dichloromethane.

[0032] Preferably, the second solvent comprises dichloromethane.

[0033] Preferably, the dripping rate of the second mixture is 4 to 5 mL / s, for example, it can be 4 mL / s, 4.2 mL / s, 4.3 mL / s, 4.4 mL / s, 4.5 mL / s, 4.6 mL / s, 4.7 mL / s, 4.8 mL / s, 4.9 mL / s or 5 mL / s, but is not limited to the listed values. Other unlisted values ​​within this range are also applicable.

[0034] Preferably, the reaction time of the second stage is 3 to 5 hours, for example, it can be 3 hours, 3.3 hours, 3.5 hours, 3.7 hours, 3.9 hours, 4.2 hours, 4.4 hours, 4.6 hours, 4.8 hours or 5 hours, but is not limited to the listed values. Other unlisted values ​​within this range are also applicable.

[0035] Preferably, the temperature of the first stage reaction is 2 to 10°C, for example, it can be 2°C, 3°C, 4°C, 5°C, 6°C, 7°C, 8°C, 9°C or 10°C, but is not limited to the listed values. Other unlisted values ​​within this range are also applicable.

[0036] Preferably, the temperature of the second stage reaction is 20 to 35°C, for example, it can be 20°C, 22°C, 24°C, 25°C, 27°C, 29°C, 30°C, 32°C, 34°C or 35°C, but is not limited to the listed values. Other unlisted values ​​within this range are also applicable.

[0037] Preferably, after the first reaction, the preparation method further includes: separating, washing and drying the material after the first reaction.

[0038] Preferably, the separation includes: mixing and stirring the material after the first reaction with water and performing liquid-liquid phase separation to obtain a first aqueous phase and a first organic phase. The organic matter in the first aqueous phase is extracted with dichloromethane, and the resulting second extracted organic phase is mixed with the first organic phase to obtain an organic product.

[0039] Preferably, the washing includes washing the organic products with a saturated sodium chloride solution.

[0040] Preferably, the drying process includes drying the organic product with anhydrous sodium sulfate.

[0041] Preferably, the second reaction comprises: directly mixing the organic product with the structure shown in formula (2), and removing the solvent and purifying to obtain the photoinitiator of the structure of formula (1).

[0042] Preferably, the solvent removal includes distillation, preferably vacuum distillation.

[0043] Preferably, the purification includes purification using a silica gel chromatography column.

[0044] Thirdly, the present invention provides a composition comprising the photoinitiator described in the first aspect, and / or a photoinitiator prepared by the method described in the second aspect.

[0045] The composition provided by the present invention contains the above-mentioned photoinitiator, which not only prevents yellowing during photopolymerization, but also has high initiation efficiency and can significantly improve the compactness of the organic-inorganic dual network structure.

[0046] Preferably, the composition further includes oligomers, monomers, and fillers.

[0047] Preferably, the oligomer content in the composition is 5% to 20%, for example, it can be 5%, 7%, 9%, 10%, 12%, 14%, 15%, 17%, 19% or 20%, etc., but is not limited to the listed values, and other unlisted values ​​within this range are also applicable.

[0048] In addition to monomers, oligomers are preferably added to the composition provided by the present invention. The presence of oligomers can combine the various components of the product together, giving it plasticity and curing properties, and enhancing its mechanical properties.

[0049] Preferably, the monomer content in the composition is 12% to 30%, for example, it can be 12%, 14%, 16%, 18%, 20%, 22%, 24%, 26%, 28% or 30%, etc., but is not limited to the listed values, and other unlisted values ​​within this range are also applicable.

[0050] Preferably, the photoinitiator in the composition is 0.01% to 4% by mass, for example, 0.01%, 0.46%, 0.9%, 1.34%, 1.79%, 2.23%, 2.67%, 3.12%, 3.56%, or 4%, but is not limited to the listed values. Other unlisted values ​​within this range are also applicable.

[0051] In this invention, it is preferable to control the amount of photoinitiator added within the above-mentioned range. This can prevent the cured parts from yellowing easily and causing aesthetic problems due to poor color stability and stain resistance, while avoiding the problems of low polymerization degree and loose double network leading to poor strength and hardness performance.

[0052] Preferably, the filler in the composition is 42% to 80% by mass, for example, 42%, 47%, 51%, 55%, 59%, 64%, 68%, 72%, 76%, or 80%, but is not limited to the listed values. Other unlisted values ​​within this range are also applicable.

[0053] Preferably, the composition further includes additives.

[0054] Preferably, the additive in the composition is 1 to 4% by mass, for example, 1%, 1.1%, 1.2%, 1.3%, 1.34%, 1.79%, 2.23%, 2.67%, 3.12%, 3.56%, or 4%, but is not limited to the listed values. Other unlisted values ​​within this range are also applicable.

[0055] Preferably, the oligomer comprises a low polyacrylate derivative.

[0056] Preferably, the oligomer comprises any one or a combination of at least two of polyurethane acrylate, epoxy acrylate, urethane dimethacrylate, bisphenol A-dimethacrylate, ethoxybisphenol A dimethacrylate, or bisphenol A glycerol dimethacrylate, wherein typical but non-limiting combinations are combinations of polyurethane acrylate and epoxy acrylate, combinations of urethane dimethacrylate and epoxy acrylate, combinations of polyurethane acrylate and urethane dimethacrylate, and combinations of phenol A-dimethacrylate and epoxy acrylate.

[0057] Preferably, the monomer comprises a radical acrylate monomer having at least one functional group. More preferably, it comprises any one or a combination of at least two of monofunctional, difunctional, or trifunctional radical acrylate monomers, wherein typical but non-limiting combinations are combinations of monofunctional and difunctional radical acrylate monomers, combinations of trifunctional and difunctional radical acrylate monomers, and combinations of monofunctional and trifunctional radical acrylate monomers.

[0058] Preferably, the monofunctional free radical acrylate monomer comprises any one or a combination of at least two of cyclotrimethylolpropane acrylate, laurate acrylate, acrylomorpholine, dicyclopentenyl acrylate, isobornyl acrylate, ethoxyphenoxy acrylate, or ethoxynonylphenol acrylate. Typical but non-limiting combinations include the combination of cyclotrimethylolpropane acrylate and laurate acrylate, the combination of acrylomorpholine and laurate acrylate, the combination of cyclotrimethylolpropane acrylate and acrylomorpholine, the combination of dicyclopentenyl acrylate and laurate acrylate, the combination of isobornyl acrylate and laurate acrylate, and the combination of ethoxynonylphenol acrylate and isobornyl acrylate.

[0059] Preferably, the bifunctional radical acrylate monomer comprises any one or a combination of at least two of ethoxybisphenol A dimethacrylate, tetraethylene glycol dimethacrylate, 1,6-hexanediol dimethacrylate, triethylene glycol dimethacrylate, tripropylene glycol dimethacrylate, tricyclodecanediethanol dimethacrylate, or dipropylene glycol dimethacrylate. Typical but non-limiting combinations include the combination of ethoxybisphenol A dimethacrylate and tetraethylene glycol dimethacrylate, the combination of 1,6-hexanediol dimethacrylate and tetraethylene glycol dimethacrylate, the combination of ethoxybisphenol A dimethacrylate and tripropylene glycol dimethacrylate, and the combination of tricyclodecanediethanol dimethacrylate and tripropylene glycol dimethacrylate.

[0060] Preferably, the trifunctional radical acrylate monomer comprises any one or a combination of at least two of the following: trimethylolpropane triacrylate, propoxylated glycerol triacrylate, trimethylolpropane trimethacrylate, tri(2-hydroxyethyl) isocyanurate triacrylate, pentaerythritol triacrylate, or ethoxylated trimethylolpropane triacrylate. Typical but non-limiting combinations include the combination of trimethylolpropane triacrylate and propoxylated glycerol triacrylate, the combination of trimethylolpropane trimethacrylate and propoxylated glycerol triacrylate, the combination of tri(2-hydroxyethyl) isocyanurate triacrylate and trimethylolpropane trimethacrylate, the combination of trimethylolpropane triacrylate and tri(2-hydroxyethyl) isocyanurate triacrylate, and the combination of pentaerythritol triacrylate and propoxylated glycerol triacrylate.

[0061] Preferably, the packing material comprises inorganic packing material.

[0062] Preferably, the inorganic filler is a silane-modified filler.

[0063] Preferably, the inorganic components in the inorganic filler include any one or a combination of at least two of barium glass powder, feldspar powder, quartz powder, sodium aluminum silicate powder, or zirconium dioxide powder. Typical but non-limiting combinations include the combination of barium glass powder and feldspar powder, the combination of quartz powder and feldspar powder, the combination of barium glass powder and quartz powder, the combination of sodium aluminum silicate powder and feldspar powder, and the combination of barium glass powder and zirconium dioxide powder.

[0064] Preferably, the additive includes any one or a combination of at least two of the following: polymerization inhibitor, defoamer, fluorescent agent, indicator, viscosity modifier, or pigment. Typical but non-limiting combinations include a combination of polymerization inhibitor and defoamer, a combination of indicator and defoamer, a combination of polymerization inhibitor and indicator, a combination of viscosity modifier and defoamer, and a combination of polymerization inhibitor and pigment.

[0065] Preferably, the preparation of the composition includes: mixing the raw materials of the composition and stirring them under light-protected conditions to obtain the composition.

[0066] Preferably, the stirring speed is 1000-3000 rpm, for example, it can be 1000 rpm, 1220 rpm, 1440 rpm, 1660 rpm, 1880 rpm, 2110 rpm, 2330 rpm, 2550 rpm, 2770 rpm or 3000 rpm, but is not limited to the listed values, other unlisted values ​​within this range are also applicable.

[0067] Preferably, the mixing time is 0.5 to 2 hours, for example, 0.5 hours, 0.7 hours, 0.9 hours, 1 hour, 1.2 hours, 1.4 hours, 1.5 hours, 1.7 hours, 1.9 hours or 2 hours, but is not limited to the listed values. Other unlisted values ​​within this range are also applicable.

[0068] Preferably, the raw materials of the mixed composition include: first mixing monomers and photoinitiators, and then sequentially adding oligomers and fillers.

[0069] Preferably, an additive is added between the oligomer and the filler in the raw materials of the mixed composition.

[0070] Fourthly, the present invention provides the application of the composition described in the first aspect in dental restorative materials.

[0071] Preferably, the composition is used to prepare ceramic crown bridge materials.

[0072] It is worth noting that the composition of the composite ceramic crown bridge composition achieves a high degree of polymerization, resulting in high strength, hardness, and molding precision; the low water absorption and stain resistance color difference value can meet the requirements of printed composite ceramic crown bridges for clinical wear.

[0073] Preferably, the preparation includes: curing the composition to obtain a ceramic crown / bridge material.

[0074] Preferably, the curing includes 3D printing photocuring.

[0075] Preferably, the light source wavelength used in the 3D printing photopolymerization is 385nm and / or 405nm.

[0076] Preferably, the temperature of the printing chamber in the 3D printing photopolymerization process is 20 to 40°C, for example, it can be 20°C, 23°C, 25°C, 27°C, 29°C, 32°C, 34°C, 36°C, 38°C or 40°C, but is not limited to the listed values. Other unlisted values ​​within this range are also applicable.

[0077] Preferably, the curing process further includes a secondary curing process following the photocuring of 3D printing.

[0078] Preferably, the secondary curing includes: curing the 3D-printed material at a light power of 50–200 mw / cm². 2 Secondary curing is performed under certain conditions, for example, 50 mw / cm². 2 67mw / cm 2 84mw / cm 2 100mw / cm 2 117mw / cm 2 134mw / cm 2 150mw / cm 2 167mw / cm 2 184mw / cm 2 Or 200mw / cm 2 This includes, but is not limited to, the listed values; other unlisted values ​​within this range also apply.

[0079] Preferably, the secondary curing time is 10 to 20 minutes, for example, it can be 10 minutes, 12 minutes, 13 minutes, 14 minutes, 15 minutes, 16 minutes, 17 minutes, 18 minutes, 19 minutes or 20 minutes, but is not limited to the listed values. Other unlisted values ​​within this range are also applicable.

[0080] Compared with the prior art, the present invention has at least the following beneficial effects:

[0081] (1) The photoinitiator provided by the present invention can reduce the problems of yellowing and low initiation efficiency of commercially available initiators during photopolymerization, and improve the compactness of the organic-inorganic dual network structure;

[0082] (2) The composition provided by this invention is a high-density dual-network printing composite ceramic crown and bridge composition. Through the combination of specific proportions of oligomers, monomers, photoinitiators, and inorganic powders, the resulting composite ceramic crown and bridge composition exhibits a high degree of polymerization reaction, high strength, hardness, and molding precision. Specifically, under preferred conditions, the flexural strength is above 200 MPa, the flexural modulus is above 8.5 GPa, the fracture toughness is above 2.51 MPa·m1 / 2, and the Vickers hardness is above 33.88 HV; it also has low water absorption and stain resistance color difference values, with a water absorption of only 17.08 μg / mm. 3 Within this range, the solubility value is only 1.71 μg / mm. 3 Within 1.8, the staining difference is within 1.8, indicating strong staining resistance. This meets the clinical requirements for printed composite ceramic crowns and bridges, and has broad application prospects. Attached Figure Description

[0083] Figure 1 This is the infrared spectrum of photoinitiator A in this invention.

[0084] Figure 2 This is the mass spectrum of photoinitiator A in this invention. Detailed Implementation

[0085] To facilitate understanding of the present invention, the following embodiments are provided. Those skilled in the art should understand that these embodiments are merely illustrative and should not be construed as limiting the scope of the invention.

[0086] It should be understood that the terms "first," "second," etc., are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Therefore, a feature defined with "first," "second," etc., may explicitly or implicitly include one or more of that feature. In the description of this invention, unless otherwise stated, "a plurality of" means two or more.

[0087] The structural formula of photoinitiator A is shown in formula (3):

[0088]

[0089] The preparation method of photoinitiator A includes the following steps:

[0090] 26.88 g of fluorobenzene and 46.69 g of aluminum trichloride were dissolved in 1.5 L of dichloromethane to obtain a first mixture, which was then placed in a water bath at 5 °C. 27.44 g of oxaloyl chloroformate was dissolved in 0.7 L of dichloromethane to obtain a second mixture. The second mixture was added dropwise to the first mixture at a rate of 4.5 mL / s while simultaneously stirring at 300 rpm to initiate the first stage of the reaction. After the addition was complete, the mixture was brought to room temperature (25 °C) and the second stage of the reaction was continued for 4 hours. After the first reaction was completed, the mixture was poured into 7 L of deionized water at 5 °C and stirred to separate the aqueous and organic layers. The aqueous layer was then extracted with dichloromethane, and the organic layers were combined, washed with saturated brine, and dried with anhydrous sodium sulfate to obtain the organic product. The organic product was uniformly mixed with 62.16 g of (2,4,6-trimethylbenzoyl)bis(p-tolyl)phosphine oxide, the solvent was removed by vacuum distillation, and the product was purified by silica gel column chromatography to obtain a pale yellow solid p-fluorobenzoylcarbamate-acylphosphine oxide, with a total yield of 61.9% by mass fraction.

[0091] The infrared spectrum and mass spectrum of the photoinitiator A prepared above are as follows: Figures 1-2 As shown, from Figure 1 It can be seen that the infrared (IR) value is at 3085 cm⁻¹. -1 3066cm -1 and 3030cm -1 =CH stretching vibration absorption at 1495cm -1 and 1450cm -1 The benzene ring skeletal vibration at 3000 cm⁻¹ indicates the presence of a benzene ring in the analyte; the CH stretching vibration of saturated carbon at 3000 cm⁻¹ and at 1430 cm⁻¹... -1 and 1320cm -1 The absorption peak at 1770-1720 cm⁻¹ indicates that the analyte contains -CH₃; -1 A broad and strong peak appears, which is the characteristic absorption peak of the ester group; 1740 cm⁻¹ -1 and 1690cm -1 The symmetrical double-shoulder peaks are two adjacent C=O characteristic absorption peaks; 1210 cm⁻¹ -1 and 1030cm -1 The absorption peak is the COC stretching vibration absorption peak; from Figure 2 As can be seen from the MS mass spectrometry, m / z 105 is the characteristic peak of C6H5CO+, m / z 39, 51, and 77 peaks indicate the presence of a benzene ring in the analyte, m / z 28 indicates the presence of a carbonyl group, and m / z 15 indicates the presence of a methyl group. This confirms that the obtained pale yellow solid is indeed p-fluorobenzoylcarbamate-acylphosphine oxide.

[0092] The structural formula of photoinitiator B is shown in formula (3):

[0093]

[0094] The preparation method of photoinitiator B includes the following steps:

[0095] 31.42 g of fluorobenzene and 46.69 g of aluminum trichloride were dissolved in 1.5 L of dichloromethane to obtain a first mixture, which was then placed in a water bath at 2 °C. 49.05 g of oxaloyl chloroformate was dissolved in 0.7 L of dichloromethane to obtain a second mixture. The second mixture was added dropwise to the first mixture at a rate of 4 mL / s while simultaneously stirring at 350 rpm to initiate the first stage of the reaction. After the addition was complete, the mixture was brought to room temperature (35 °C) and the second stage of the reaction was continued for 5 hours. After the first reaction was completed, the mixture was poured into 7 L of deionized water at 5 °C and stirred to separate the aqueous and organic layers. The aqueous layer was then extracted with dichloromethane, and the organic layers were combined, washed with saturated brine, and dried with anhydrous sodium sulfate to obtain the organic product. The organic product was uniformly mixed with 77.13 g of (2,4,6-trimethylbenzoyl)bis(p-tolyl)phosphine oxide, the solvent was removed by vacuum distillation, and the product was purified by silica gel column chromatography to obtain a pale yellow solid p-fluorobenzoylcarbamate-acylphosphine oxide, with a total yield of 60.85% by mass fraction.

[0096] The structural formula of photoinitiator C is shown in formula (3):

[0097]

[0098] The preparation method of the photoinitiator C includes the following steps:

[0099] 26.88 g of fluorobenzene and 46.69 g of aluminum trichloride were dissolved in 1.5 L of dichloromethane to obtain a first mixture, which was then placed in a 10 °C water bath. 27.44 g of oxaloyl chloroformate was dissolved in 0.7 L of dichloromethane to obtain a second mixture. The second mixture was added dropwise to the first mixture at a rate of 5 mL / s while simultaneously stirring at 300 rpm to initiate the first stage of the reaction. After the addition was complete, the mixture was brought to room temperature (20 °C) and the second stage of the reaction was continued for 3 hours. After the first reaction was completed, the mixture was poured into 7 L of deionized water at 5 °C and stirred to separate the aqueous and organic layers. The aqueous layer was then extracted with dichloromethane, and the organic layers were combined, washed with saturated brine, and dried with anhydrous sodium sulfate to obtain the organic product. The organic product was uniformly mixed with 84.79 g of (2,4,6-trimethylbenzoyl)bis(p-tolyl)phosphine oxide, the solvent was removed by vacuum distillation, and the product was purified by silica gel column chromatography to obtain a pale yellow solid p-fluorobenzoylcarbamate-acylphosphine oxide, with a total yield of 63.47% by mass fraction.

[0100] The structural formula of photoinitiator D is shown in formula (4):

[0101]

[0102] The preparation process of photoinitiator D was the same as that of photoinitiator A, except that fluorobenzene was replaced with an equimolar amount of chlorobenzene. The overall yield by mass fraction was 58.64%.

[0103] The structural formula of photoinitiator E is shown in formula (5):

[0104]

[0105] The preparation process of photoinitiator E is the same as that of photoinitiator A, except that fluorobenzene is replaced with an equimolar amount of benzene. The total yield by mass fraction is 60.27%.

[0106] The structural formula of photoinitiator F is shown in formula (6):

[0107]

[0108] The preparation of photoinitiator F was the same as that of photoinitiator A, except that (2,4,6-trimethylbenzoyl)bis(p-tolyl)phosphine oxide was replaced with an equimolar amount of (2,4,6-trimethylbenzoyl)bis(phenyl)phosphine oxide. The overall yield by mass fraction was 63.18%.

[0109] The structural formula of photoinitiator G is shown in formula (7):

[0110]

[0111] The preparation process of photoinitiator G was the same as that of photoinitiator A, except that fluorobenzene was replaced with an equimolar amount of iodobenzene. The overall yield by mass fraction was 56.97%.

[0112] Generally, this invention does not have special requirements for the selection of pigments; any pigment known to those skilled in the art for use in 3D printing ceramic compositions can be used. For ease of experimental comparison, the pigments used in the following examples and comparative examples are 45 wt% titanium dioxide, 23 wt% iron oxide yellow, 27 wt% iron oxide red, and 5 wt% iron oxide black. The fillers used in the following examples and comparative examples are all silane-modified fillers; specifically, the silane modification method is KH570 hydrolysis silanization modification. The specific composition of the barium glass powder is 27% barium oxide, 50% silicon dioxide, 10% boron oxide, 10% aluminum oxide, and 3% fluoride.

[0113] Example 1

[0114] This embodiment provides a composition comprising, based on a total weight of 100 parts: 18 parts of urethane dimethacrylate (oligomer), 6 parts of acryloylmorpholine (monofunctional radical acrylate monomer), 10 parts of tripropylene glycol diacrylate (bifunctional radical acrylate monomer), 3 parts of photoinitiator A, 60 parts of barium glass powder (filler), 2.5 parts of colorant (additive), and 0.5 parts of p-hydroxyanisole (additive).

[0115] This embodiment also provides a method for preparing the composition, the specific steps of which include: mixing each raw material component according to the formula amount and mass fraction ratio, wherein the raw materials of the mixed composition include: first mixing monomers and photoinitiators, then adding oligomers, additives and fillers in sequence, and then stirring at 1500 rpm for 1.5 h at room temperature in the dark to obtain the composition.

[0116] Example 2

[0117] This embodiment provides a composition comprising, based on a total weight of 100 parts: 15 parts epoxy acrylate (oligomer), 10 parts triethylene glycol dimethacrylate (bifunctional radical acrylate monomer), 10 parts trimethylolpropane trimethacrylate (trifunctional radical acrylate monomer), 4 parts photoinitiator B, 58 parts feldspar powder (filler), 2.5 parts colorant (additive), and 0.5 parts p-hydroxyanisole (additive).

[0118] This embodiment also provides a method for preparing the composition, the specific steps of which include: mixing each raw material component according to the formula amount and mass fraction ratio, wherein the raw materials of the mixed composition include: first mixing monomers and photoinitiators, then adding oligomers, additives and fillers in sequence, and then stirring at 1000 rpm for 2 hours at room temperature in the dark to obtain the composition.

[0119] Example 3

[0120] This embodiment provides a composition comprising, based on a total weight of 100 parts: 16 parts bisphenol A-dimethacrylate glycidyl ester (oligomer), 16 parts isobornyl acrylate (monofunctional free radical acrylate monomer), 2.5 parts photoinitiator C, 32.5 parts sodium aluminum silicate powder (filler), 30 parts barium glass powder (filler), 2.5 parts colorant (additive), and 0.5 parts p-hydroxyanisole (additive).

[0121] This embodiment also provides a method for preparing the composition, the specific steps of which include: mixing each raw material component according to the formula amount and mass fraction ratio, wherein the raw materials of the mixed composition include: first mixing monomers and photoinitiators, then adding oligomers, additives and fillers in sequence, and then stirring at 3000 rpm for 0.5 h at room temperature in the dark to obtain the composition.

[0122] Example 4

[0123] This embodiment provides a composition comprising, based on a total weight of 100 parts: 20 parts bisphenol A-dimethacrylate glycidyl ester (oligomer), 30 parts isobornyl acrylate (monofunctional free radical acrylate monomer), 4 parts photoinitiator C, 42 parts barium glass powder (filler), 3 parts colorant (additive), and 1 part p-hydroxyanisole (additive). The preparation method is the same as in Example 1.

[0124] Example 5

[0125] This embodiment provides a composition comprising, based on a total weight of 100 parts: 5 parts urethane dimethacrylate (oligomer), 12 parts isobornyl acrylate (monofunctional free radical acrylate monomer), 1 part photoinitiator A, 79.01 parts barium glass powder (filler), 2 parts colorant (additive), and 0.99 parts p-hydroxyanisole (additive). The preparation method is the same as in Example 1.

[0126] Example 6

[0127] This embodiment provides a composition, which is the same as in Example 1 except that the weight of photoinitiator A is 5 parts and the weight of other components is reduced proportionally. It will not be described again here.

[0128] Example 7

[0129] This embodiment provides a composition that is identical to that of Example 1 except that no oligomers are added and the mass fractions of the oligomers are proportionally distributed to the other components. It will not be repeated here.

[0130] Example 8

[0131] This embodiment provides a composition that is identical to that in Example 1 except that photoinitiator A is replaced with photoinitiator D, and will not be described again here.

[0132] Example 9

[0133] This embodiment provides a composition that is identical to that in Example 1 except that photoinitiator A is replaced with photoinitiator E, and will not be described again here.

[0134] Example 10

[0135] This embodiment provides a composition that is identical to that in Example 1 except that photoinitiator A is replaced with photoinitiator F, and will not be described again here.

[0136] Example 11

[0137] This embodiment provides a composition that is identical to that in Example 1 except that photoinitiator A is replaced with photoinitiator G, and will not be described again here.

[0138] Comparative Example 1

[0139] This comparative example provides a composition that is identical to that in Example 1, except that photoinitiator A is replaced with (2,4,6-trimethylbenzoyl)bis(p-tolyl)phosphine oxide, and will not be described again here.

[0140] Comparative Example 2

[0141] This comparative example provides a composition that is identical to that of Example 1 except that photoinitiator A is replaced with bis(4-methylphenyl)phosphine oxide, and will not be described again here.

[0142] Application Example 1

[0143] This application example provides an application of the composition in 3D printing composite ceramics, the application including:

[0144] 3D printing was performed using the composition provided in Example 1. The 3D printing was conducted at a wavelength of 405nm. The printing chamber was heated, and hot air was circulated internally by a 33°C hot air blower to complete the first curing. The second curing was a post-processing step using a 405nm wavelength light source, with an optical power of 150mw / cm² in the curing chamber. 2 The secondary curing time was 15 minutes, resulting in a highly dense dual-network printed composite ceramic crown bridge material.

[0145] Application Example 2

[0146] This application example provides an application of the composition in 3D printing composite ceramics, the application including:

[0147] 3D printing was performed using the composition provided in Example 1. The 3D printing was conducted at a wavelength of 405nm. The printing chamber was heated, and hot air was circulated internally by a 40°C hot air blower to complete the first curing step. The second curing step involved post-processing using a 405nm wavelength light source, with the curing chamber having an optical power of 200mw / cm². 2 The secondary curing time was 10 minutes, resulting in a highly dense dual-network printed composite ceramic crown bridge material.

[0148] Application Example 3

[0149] This application example provides an application of the composition in 3D printed composite ceramics, the application including:

[0150] 3D printing was performed using the composition provided in Example 1. The 3D printing was conducted at a wavelength of 385nm. The printing chamber was heated, and hot air was circulated internally by a 20°C hot air blower to complete the first curing. The second curing was a post-processing step using a 385nm wavelength light source, with an optical power of 50mw / cm² in the curing chamber. 2 The secondary curing time was 20 minutes, resulting in a highly dense dual-network printed composite ceramic crown bridge material.

[0151] Application Examples 4-11 and Comparative Examples 1-2

[0152] Application Examples 4-11 and Comparative Examples 1-2 provide an application of the composition in 3D printed composite ceramics. The application of the composition in 3D printed composite ceramics is the same as that in Application Example 1, except that the compositions in Examples 4-11 and Comparative Examples 1-2 are used respectively, and will not be described again here.

[0153] Test method:

[0154] Flexural strength: ISO 10477-YY0710 "Dental Science - Polymer-based Crown and Bridge Materials"

[0155] Flexural modulus: ISO 10477-YY0710 "Dental Science - Polymer-based Crown and Bridge Materials"

[0156] Fracture toughness: 20795-2-YY0270.2 《Dental Base Polymers Part 2: Orthodontic Base Polymers》

[0157] Vickers Hardness: ISO 6507.1 - GB / T 4340.1 "Metallic materials - Vickers hardness test - Part 1: Test method"

[0158] Water absorption value: ISO4049-YY1042 "Polymer-based restorative materials in dentistry"

[0159] Solubility value: ISO 4049-YY1042 "Polymer-based restorative materials in dentistry"

[0160] Stain resistance: YY / T1932—2024 "Dentistry - Membrane-type Alignerless Orthodontic Appliances"

[0161] The test results of the above application examples and application comparison examples are shown in Table 1.

[0162] Table 1

[0163]

[0164] The following points can be observed from Table 1:

[0165] (1) As can be seen from the comprehensive application examples 1-4, the photoinitiator provided by the present invention has excellent mechanical properties when used as a dental restorative material. Specifically, its flexural strength is above 200 MPa, its flexural modulus is above 8.5 GPa, its fracture toughness is above 2.51 MPa·m1 / 2, its Vickers hardness is above 33.88 HV, and its water absorption is low, only 17.08 μg / mm². 3 Within this range, the solubility value is only 1.71 μg / mm. 3 Within 1.8, the difference in anti-staining value is within 1.8, indicating strong anti-staining ability.

[0166] (2) Combining Application Example 1 and Application Example 6, it can be seen that the addition of 3 parts of photoinitiator in Application Example 1, compared with the use of 5 parts of photoinitiator in Application Example 6, results in better color stability and anti-dyeing performance of the product in Application Example 1. This indicates that the present invention preferably controls the amount of photoinitiator added within a reasonable range, which can better improve product performance.

[0167] (3) Combining Application Example 1 and Application Example 7, it can be seen that in Application Example 7, without the addition of oligomers, the mechanical properties of the product deteriorate, and the strength and hardness decrease significantly.

[0168] (4) Compared with Comparative Examples 1 to 2, the application examples 8 to 11 of photoinitiators D, E, F, and G with different structures also have certain mechanical and aesthetic properties, but they are worse than those of application example 1. Specifically, X is chlorine in application example 8, iodine in application example 11, and no X in application example 9, while X is fluorine in application example 1. The F bond in application example 1 has a similar effect to low surface energy, which has a better anti-staining effect and significantly better mechanical properties. Application example 10 contains phenyl-phosphorus chemical bonds, which poses a biosafety risk and is difficult to apply in dental materials. Moreover, its mechanical and anti-staining properties are relatively worse.

[0169] The present invention has been illustrated with the above embodiments to illustrate its detailed features, but the present invention is not limited to the above detailed features, that is, it does not mean that the present invention must rely on the above detailed features to be implemented. Those skilled in the art should understand that any improvements to the present invention, equivalent substitutions for the selected technical features, additions of auxiliary technical features, and selection of specific methods, etc., all fall within the protection scope and disclosure scope of the present invention.

Claims

1. A photoinitiator characterized by, The structure of the photoinitiator is shown as formula (1): Formula (1); In formula (1), X is halogen element or hydrogen, R1 and R2 are each independently any one of tolyl, ethylbenzene, phenyl or propylbenzene or a combination of at least two, Y1 and Y2 are each independently alkyl with carbon number of 1-5.

2. Photoinitiator according to claim 1, characterized in that In formula (1), X includes any one of fluorine, bromine, chlorine or iodine.

3. Photoinitiator according to claim 1 or 2, characterized in that R1 and R2 are each independently p-methylphenyl.

4. Photoinitiator according to claim 1 or 2, characterized in that Y1 and Y2 are each independently methyl.

5. A process for the preparation of a photoinitiator according to any one of claims 1 to 4, characterized in that The preparation method comprises: oxalyl chloride ester and halobenzene are subjected to a first reaction to prepare p-halobenzoyl ester; the p-halobenzoyl ester is subjected to a second reaction with a structure shown as formula (2) to prepare the photoinitiator of formula (1); Formula (2); In formula (2), R3 is aromatic hydrocarbon group.

6. The preparation method according to claim 5, characterized in that, The oxalyl chloride ester is oxalyl chloride formate.

7. The preparation method according to claim 5, characterized in that, The p-halobenzoyl ester is p-halobenzoyl formate.

8. The preparation method according to claim 5, characterized in that, In the structure shown as formula (2), R3 is any one of substituted phenyl, benzyl or phenethyl or a combination of at least two.

9. The preparation method according to claim 5, characterized in that, The mass ratio of the oxalyl chloride ester and halobenzene is 1.02-1.6:

1.

10. The method of claim 5, wherein, The mass ratio of the structure shown as formula (2) and the p-halobenzoyl ester is 2.3-3.2:

1.

11. The preparation method according to claim 5, characterized in that, The first reaction is performed under catalysis of a catalyst.

12. The method of claim 11, wherein, The catalyst includes aluminum trichloride.

13. The method of claim 12, wherein, The mass ratio of the aluminum trichloride and halobenzene is 1.4-1.75:

1.

14. A composition characterized in that, The composition includes the photoinitiator of any one of claims 1-4 and / or the photoinitiator prepared by the preparation method of any one of claims 5-13.

15. The composition of claim 14, wherein, The composition further includes oligomer, monomer and filler.

16. The composition of claim 14, wherein, The mass fraction of the oligomer in the composition is 5-20%.

17. The composition of claim 15, wherein, The mass fraction of the monomer in the composition is 12-30%.

18. The composition of claim 15, wherein, The mass fraction of the photoinitiator in the composition is 1-4%.

19. The composition of claim 15, wherein, The mass fraction of the filler in the composition is 42-80%.

20. The composition of claim 15, wherein, The oligomer includes oligomeric acrylate derivative.

21. The composition of claim 7, wherein, The monomer includes free radical acrylate monomer with at least one functional group.

22. Use of the composition of any one of claims 14-21 in dental restorative material.

23. The use according to claim 22, characterized in that, The composition is used for preparing ceramic crown and bridge material.

24. The use according to claim 23, characterized in that, The preparation comprises curing the composition to obtain ceramic crown and bridge material.

25. The use according to claim 24, characterized in that, The curing comprises 3D printing light curing.

26. The use according to claim 25, characterized in that, The curing further comprises secondary curing after 3D printing light curing.

27. The use according to claim 26, characterized in that, The secondary solidification includes: the material after 3D printing light solidification is subjected to secondary solidification in the condition that the light power is 50-200 mW / cm 2 .

Images