3D printing resin and preparation method thereof

Abstract

The invention relates to the technical field of 3D printing materials, and discloses 3D printing resin and a preparation method thereof. The adhesive comprises the following components in percentage by mass: 40-70% of a polyurethane acrylic resin oligomer containing a latent isocyanate group; 15%-50% of a reactive diluent; 3%-8% of a curing agent; 0.5%-10% of a photoinitiator; 0.1%-1.2% of an ultraviolet absorbent; 0.05%-0.2% of a defoaming agent; 0.5%-5% of a dispersant; 0.1%-0.5% of an antioxidant; wherein the curing agent is solid hydrazide of which the surface is modified by a surfactant. The preparation method comprises the following steps: taking a polyurethane acrylic resin oligomer containing a latent isocyanate group, adding the reactive diluent, uniformly stirring, then adding the photoinitiator, the ultraviolet absorbent and the sensitizer, uniformly stirring, then adding the dispersing agent and the curing agent, uniformly stirring, then adding the flatting agent, the defoaming agent and the antioxidant, uniformly stirring, and finally adding the curing agent, the flatting agent and the antioxidant. And finally, rolling and grinding. The 3D printing resin provided by the invention has excellent mechanical properties and long-term weather resistance, and can maintain room temperature storage stability as long as 6 months.

Description

Technical Field

[0001] This invention relates to the field of 3D printing materials technology, specifically to a 3D printing resin and its preparation method. Background Technology

[0002] 3D technology, also known as additive manufacturing, commonly uses resins such as standard resins, high-temperature resins, ABS-like resins, tough resins, and washable resins. Because its curing process is a simple free radical photopolymerization process, it is formed by the rapid polymerization of monomers or oligomers with small molecular weights during the photopolymerization process. This results in a large amount of internal stress. The random polymerization of molecules also leads to poor strength, toughness, elasticity, and tear resistance of the material. At the same time, the product's weather resistance is also very poor, which cannot meet the requirements of consumers for long-term use.

[0003] In recent years, two-component 3D printing resins have been introduced. These two-component resins contain both photocurable groups and end-capped thermocurable groups. Due to the use of highly active chain extenders, the stability after mixing is extremely poor (it usually gels within 24 hours). Customers are required to mix components A and B before use, which increases the complexity of the operation. At the same time, it is necessary to ensure that the resin is consumed quickly after mixing to meet the usage requirements, which greatly limits the scope of application of the resin. In addition, this resin has extremely high requirements for printing equipment, the equipment is expensive, and there is a lot of resin material wasted during use.

[0004] Therefore, how to solve the storage stability of mixed two-component resins is an urgent problem to be solved. Summary of the Invention

[0005] The present invention aims to solve at least one of the technical problems existing in the prior art or related art.

[0006] Therefore, in a first aspect, the present invention provides a 3D printing resin comprising the following components by weight percentage: Polyurethane acrylic resin oligomers containing latent isocyanate groups: 40%-70%; Reactive diluent: 15%-50%; Hardener: 3%-8%; Photoinitiator: 0.5%-10%; UV absorber: 0.1%-1.2%; Defoamer: 0.05%-0.2%; Dispersant: 0.5%-5%; Antioxidant: 0.1%-0.5%; The curing agent is a solid acylhydrazine compound with surface-modified surfactant.

[0007] Optionally, the 3D printing resin comprises the following components by weight percentage: Polyurethane acrylic resin oligomers containing latent isocyanate groups: 40%-70%; Reactive diluent: 15%-50%; Hardener: 3%-5%; Photoinitiator: 2%-4%; UV absorber: 0.1%-0.2%; Defoamer: 0.05%-0.2%; Dispersant: 0.5%-1.5%; Antioxidant: 0.2%-0.4%.

[0008] Optionally, the 3D printing resin further includes the following components in weight percentage: Leveling agent: 0.2%-0.4%; Sensitizer: 0.2%-1.5%.

[0009] Optionally, the polyurethane acrylic resin oligomer containing latent isocyanate groups is prepared by a method comprising: The isocyanate and organotin catalyst were mixed to obtain the first mixture; A polyol was added to the first mixture, and the mixture was reacted at 58℃-62℃ for 1.5h-2.5h to obtain the second mixture. The second mixture was cooled to 30°C-40°C, and a polymerization inhibitor and a capping agent were added to obtain a third mixture; The third mixture is heated to 48℃-52℃ and reacted for 1.5h-2.5h. After the reaction is completed, the mixture is cooled and discharged to obtain the polyurethane acrylic resin oligomer containing latent isocyanate groups.

[0010] Optionally, the 3D printing resin must meet at least one of the following conditions: The isocyanate is a difunctional isocyanate; The polyol is a polyether polyol or a polyester polyol; The organotin catalyst is dibutyltin dilaurate and / or stannous octoate; The polymerization inhibitor is p-hydroxyanisole; The capping agent is tert-butylaminoethyl methacrylate.

[0011] Optionally, the reactive diluent comprises a low molecular weight compound containing acrylate groups and / or methacrylate groups.

[0012] Optionally, the reactive diluent includes one or more of the following: acrylamide, dipropylene glycol diacrylate, tripropylene glycol diacrylate, diethylene glycol dimethacrylate, tri(2-hydroxyethyl) isocyanurate triacrylate, laurate, laurate methacrylate, polyethylene glycol diacrylate, polyethylene glycol dimethacrylate, and isobornyl methacrylate.

[0013] Optionally, the curing agent includes adipamide, heptane dihydrazide, polyethylene glycol dihydrazide, sebacate dihydrazide, isophthalic acid dihydrazide, dodecane dicarboxylic acid dihydrazide, and / or isophthalic acid dihydrazide, which are surface-modified surfactants.

[0014] Optionally, the surfactant is adsorbed onto the surface of the solid hydrazide particles by physical adsorption.

[0015] Optionally, the photoinitiator absorbs ultraviolet and / or visible light to generate free radicals that initiate the polymerization of acrylate groups.

[0016] Optionally, the photoinitiator includes one or more of the following: phenylbis(2,4,6-trimethylbenzoyl)phosphine oxide, ethyl 2,4,6-trimethylbenzoylphosphonate, diphenyl(2,4,6-trimethylbenzoyl)phosphine oxide, 1-hydroxycyclohexylphenyl ketone, 2-isopropylthioxanthraphenone (a mixture of 2,4 isomers), and 2-methyl-1-[4-methylthiophenyl]-2-morpholino-1-propanone.

[0017] Optionally, the ultraviolet absorber includes one or more of benzotriazoles, triazines, anthocyanins, and aniline black.

[0018] Optionally, the defoamer includes one or more of the following: polysiloxane-polyether block copolymer, hydroxyl-terminated polydimethylsiloxane, hydrophobic silica-modified polydimethylsiloxane, polyethylene glycol-polypropylene glycol block copolymer, and mineral oil-based complex. The leveling agent includes one or more of the following: fluorinated polyacrylate, polyether-modified polysiloxane, polyether-modified polydimethylsiloxane, polyester-modified hydroxyl-functionalized polydimethylsiloxane, and organosilicon-acrylate copolymer. The sensitizer includes one or more of 2,4-diethylthioxanthanone, 2-isopropylthioxanthanone, 1-chloro-4-propoxythioxanthanone, and 2,4-bis(2,4-dimethoxyphenyl)-6-(4-methoxyphenyl)-1,3,5-triazine.

[0019] Optionally, the dispersant includes polyester block copolymers and / or polyurethane copolymers.

[0020] Optionally, the polyester block copolymer includes: polyurethane-modified polyester block copolymer and / or acidic polyester block copolymer; the polyurethane copolymer includes: carboxylated polyurethane copolymer, amine-modified polyester polyurethane copolymer and / or phosphate-modified polyurethane block copolymer.

[0021] Optionally, the antioxidant includes one or more of N,N'-bis(3,5-di-tert-butyl-4-hydroxyphenylpropionyl)hexanediamine, dilaurate thiodipropionate, pentaerythritol tetrakis[β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate] and tris(2,4-di-tert-butylphenyl)phosphite compound antioxidants, pentaerythritol tetrakis[β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate], octadecyl β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate, and isooctyl 3,5-di-tert-butyl-4-hydroxyphenylpropionate.

[0022] A second aspect of the present invention provides a method for preparing the above-mentioned 3D printing resin, comprising: The polyurethane acrylic resin oligomer containing latent isocyanate groups is mixed with the reactive diluent to obtain a fourth mixture; The photoinitiator and the ultraviolet absorber are added to the fourth mixture to obtain the fifth mixture; Adding the dispersant and the curing agent to the fifth mixture yields a sixth mixture; Add the defoamer and the antioxidant to the sixth mixture to obtain a resin mixture system; The resin mixture is rolled and milled, and then filtered to obtain the 3D printing resin.

[0023] Compared to existing technologies, it has at least the following beneficial effects: The 3D printing resin provided by this invention is a 3D printing resin that uses a surface-modified solid acyl hydrazine as a curing agent. A surfactant layer is adsorbed onto the surface of the acyl hydrazine through intermolecular forces, isolating the acyl hydrazine chain extender from the resin matrix (a polyurethane acrylic resin oligomer containing latent isocyanate groups). This prevents the acyl hydrazine from reacting with the polyurethane acrylic resin oligomer containing latent isocyanate groups at room temperature. However, when heated to a certain temperature, such as 100℃-120℃, the modified surfactant detaches from the acyl hydrazine surface, and the solid acyl hydrazine melts. This allows the acyl hydrazine to react rapidly with the isocyanate (NCO) groups in the polyurethane acrylic resin oligomer containing latent isocyanate groups. During thermosetting, the acyl hydrazine and NCO chain extend to generate high molecular weight thermoplastic polyurethane (TPU), while during photocuring, a cross-linked acrylate network is formed. This results in a structure within the resin of a photocured cross-linked network and a high molecular weight TPU interpenetrating polymer network (IPN), significantly improving the resin's mechanical properties. Detailed Implementation

[0024] To better understand the above technical solutions, the technical solutions of the present invention will be described in detail below through specific embodiments.

[0025] A first aspect of the present invention provides a 3D printing resin, which comprises the following components by weight percentage: Polyurethane acrylic resin oligomers containing latent isocyanate groups: 40%-70%; Reactive diluent: 15%-50%; Hardener: 3%-8%; Photoinitiator: 0.5%-10%; UV absorber: 0.1%-1.2%; Defoamer: 0.05%-0.2%; Dispersant: 0.5%-5%; Antioxidant: 0.1%-0.5%; The curing agent is a solid acylhydrazine compound with surface-modified surfactant.

[0026] The 3D printing resin provided by this invention can be composed of a mixture of component A (containing a polyurethane acrylic resin oligomer with latent isocyanate groups), an active diluent, a photoinitiator, and other additives, and a curing agent component B. This 3D printing resin can be manufactured with components A and B pre-mixed, eliminating the need for customers to mix components A and B before use, greatly simplifying the process and lowering the barrier to entry. Furthermore, this resin exhibits long-term stability, excellent mechanical properties, good resilience and flexural strength, and long-term weather resistance. Compared to existing two-component resins with a usage time of only 8-24 hours after mixing, the two-component resin of this invention achieves 6 months of room temperature storage stability after mixing, with a viscosity increase of less than 20% after six months at room temperature. This significantly improves printing success rate and eliminates time limitations, while also reducing material waste caused by crosslinking. Statistics show that existing two-component resins have a waste rate as high as 30%, and the gel resin produced by crosslinking easily pollutes soil and water. This invention, by solving the storage stability problem, achieves near 100% material utilization, and its mechanical properties, elasticity, and weather resistance are superior to existing two-component resins. Furthermore, this resin maintains relatively high stability even at 50℃. After two weeks of storage at 50℃, the resin viscosity increases by less than 20%, meeting the requirement of reducing viscosity through heating to increase printing speed. Regarding weather resistance, after two years of accelerated aging tests under simulated normal conditions, the performance retention of samples printed with this resin is significantly better than that of ordinary 3D printing resins: the tensile strength decreases by ≤10%, the elongation at break decreases by ≤15%, and other properties decrease by less than 20%; ordinary 3D printing resins generally experience a decrease of over 60% in tensile strength and elongation at break, and even cracking. In summary, this resin breaks the dependence on printing equipment and can be printed on ordinary DLP, LCD, or SLA photopolymerization printing equipment. Printed products, after heat treatment, exhibit excellent tensile strength, elasticity, and tear resistance. Moreover, due to its good weather resistance, it can meet the needs of various applications such as seat cushions, footwear, and medical supplies. It is understandable that transporting the 3D printing resin in two or more components could further extend its storage time. The separated set of components includes at least a curing agent. Optionally, the curing agent may also be stored mixed with some or all of the reactive diluent as a set of components.

[0027] Optionally, the 3D printing resin also includes the following components in percentage by weight: Leveling agent: 0.2%-0.4%; Sensitizer: 0.2%-1.5%; Preferably, the 3D printing resin comprises the following components by weight percentage: Polyurethane acrylic resin oligomers containing latent isocyanate groups: 40%-70%; Reactive diluent: 15%-50%; Hardener: 3%-5%; Photoinitiator: 2%-4%; UV absorber: 0.1%-0.2%; Defoamer: 0.05%-0.2%; Dispersant: 0.5%-1.5%; Antioxidant: 0.2%-0.4%.

[0028] The curing agent is a solid acyl hydrazine compound with a surface-modified surfactant. The surfactant is adsorbed onto the surface of the solid acyl hydrazine particles through intermolecular forces, forming a coating layer.

[0029] Optionally, the leveling agent in the 3D printing resin has a mass percentage of 0.2%-0.4%, and the sensitizer has a mass percentage of 0.2%-0.4%. Among them, polyurethane acrylic resin oligomers containing latent isocyanate groups are key components of photothermal dual-curing resins, providing basic mechanical properties for the resin. The latent isocyanate groups introduced into the polyurethane acrylic resin oligomers can react with hydrazine curing agents during heating to achieve further chain extension, thereby significantly improving the mechanical properties of the cured material.

[0030] In this embodiment of the invention, excess isocyanate is reacted with polyol to construct a polyurethane backbone, resulting in a polymer containing terminal isocyanate. Then, a polymerization inhibitor is added to suppress polymerization, and then the end-capping agent tert-butylaminoethyl methacrylate (TBAEMA) is added to synthesize a polyurethane acrylic resin oligomer that has both acrylate photocurable groups and latent isocyanate groups.

[0031] Optionally, the polyurethane acrylic resin oligomer containing latent isocyanate groups is prepared by a method comprising: The isocyanate and organotin catalyst were mixed to obtain the first mixture; Add a polyol to the first mixture and react at 58℃-62℃ for 1.5h-2.5h to obtain the second mixture; The second mixture was cooled to 30℃-40℃, and a polymerization inhibitor and a capping agent were added to obtain the third mixture; The third mixture was heated to 48℃-52℃ and reacted for 1.5h-2.5h. After the reaction was completed, the mixture was cooled and discharged to obtain polyurethane acrylic resin oligomers containing latent isocyanate groups.

[0032] The polymerization inhibitor is p-hydroxyanisole (MEHQ), and the end-capping agent is tert-butylaminoethyl methacrylate (TBAEMA).

[0033] The isocyanate is a difunctional isocyanate, preferably including isophorone diisocyanate (IPDI), hexamethylene diisocyanate (HDI), toluene diisocyanate (TDI), 4,4'-dicyclohexylmethane diisocyanate (HMDI), etc.; the polyol is a polyether polyol or a polyester polyol, usually with a molecular weight of 600-10000. The polyols used include: polytetrahydrofuran ether polyol PTMEG series (molecular weight 650, 1000, 2000, 3000, 4000, etc.) and polypropylene glycol PPG series (molecular weight 1000, 2000, 3000, 5000, 8000, etc.). The polyols used in this invention are not limited to these. Theoretically, all polyols containing hydroxyl (OH) can be used to synthesize polyurethane acrylic resin oligomers.

[0034] In the embodiments of this invention, a series of polyurethane acrylic resin oligomers containing latent isocyanate groups were synthesized, and representative examples are shown in Table 1 below: Table 1. List of raw materials for the synthesis of polyurethane acrylic resin oligomers containing latent isocyanate groups.

[0035] Reactive diluents are small molecules containing acrylic acid groups. Their main function is to reduce resin viscosity and adjust the mechanical properties of photosensitive resins. Preferred diluents include one or more of the following: acrylamide (ACMO), dipropylene glycol diacrylate (DPGDA), tripropylene glycol diacrylate (TPGDA), diethylene glycol dimethacrylate (DEGDMA), tri(2-hydroxyethyl) isocyanurate triacrylate (THEICTA), laurate acrylate (LA), laurate methacrylate (LMA), polyethylene glycol diacrylate (PEGDA), polyethylene glycol dimethacrylate (PEGDMA), isobornyl methacrylate (IBOMA), and isobornyl acrylate (IBOA).

[0036] The curing agent is an acylhydrazine compound, which is a type of compound containing an acylhydrazine group. It is a latent curing agent, a solid powder at room temperature, and insoluble in reactive diluents and polyurethane acrylic resin oligomers containing latent isocyanate groups. It does not react with isocyanate groups at room temperature. In this invention, the surface of the acylhydrazine particles is coated with a surfactant, thereby isolating the acylhydrazine from the isocyanate groups and further improving the stability of the resin. The preferred surfactant is a nonionic surfactant, such as a polyether surfactant. When heated to a certain temperature, such as 100℃-120℃, the acyl hydrazine melts and the surfactant desorbs, while the isocyanate protecting group (TBAEMA) desorbs, thereby allowing the acyl hydrazine group to react with the isocyanate group, improving the overall mechanical properties of the resin. Preferred curing agents are one or more compounds with acyl hydrazine groups, such as adipamide (molecular weight 174), heptane dihydrazine (molecular weight 188), polyethylene glycol dihydrazine, sebacyl hydrazine (molecular weight 230), isophthalic acid dihydrazine (molecular weight 194), dodecane dicarboxylic acid dihydrazine (molecular weight 258), and isophthalic acid dihydrazine (molecular weight 194).

[0037] Photoinitiators are photosensitive compounds that can absorb ultraviolet or visible light to generate free radicals, thereby initiating the polymerization of acrylate groups. Preferred photoinitiators include one or more of the following: phenyl bis(2,4,6-trimethylbenzoyl)phosphine oxide, ethyl 2,4,6-trimethylbenzoylphosphonate, diphenyl(2,4,6-trimethylbenzoyl)phosphine oxide, 1-hydroxycyclohexylphenyl ketone, 2-isopropylthioxanthone (a mixture of 2,4 isomers), and 2-methyl-1-[4-methylthiophenyl]-2-morpholino-1-propanone.

[0038] UV absorbers have strong absorption of ultraviolet light, which can rapidly attenuate the light intensity within a thin layer, thereby controlling the cured layer thickness and preventing excessive curing time in the Z-axis direction. Preferred UV absorbers include one or more of the following: benzotriazoles (UV-327, UV-P), triazines (UV-400), anthocyanins, aniline black, and other UV absorbers with strong absorption of ultraviolet light.

[0039] Defoamers primarily function to inhibit and eliminate air bubbles, preventing them from forming during the printing process due to the vertical movement of the printing platform and affecting the quality of the printed product. Preferred defoamers include one or more of the following defoamers that can be used with UV-curable resins: polysiloxane-polyether block copolymers (e.g., UNIQ®FOAM 7032 from UCAR Chemicals), hydroxyl-terminated polydimethylsiloxanes (e.g., TEGO Airex 900 from DIG), hydrophobic silica-modified polydimethylsiloxanes (e.g., TEGO Airex 920 from DIG), polyethylene glycol-polypropylene glycol block copolymers (e.g., BYK-024 from BYK Chemicals), and mineral oil-based complexes (e.g., Defoamex 820N).

[0040] Leveling agents are primarily used to reduce the surface tension of photosensitive resins, thereby accelerating their leveling speed, reducing the waiting time for each layer during printing, and improving printing efficiency. Preferred leveling agents include fluorinated polyacrylates (e.g., KYC-617 from Kyocera Chemicals, South Korea), polyether-modified polysiloxanes (e.g., TEGO Rad 2600 and TEGORad 2700 from Evonik, Germany, and BYK-377 from BYK Chemicals, Germany), polyether-modified polydimethylsiloxanes (e.g., BYK-333 from BYK Chemicals, Germany), polyester-modified hydroxyl-functionalized polydimethylsiloxanes (e.g., BYK-3500 from BYK Chemicals, Germany), silicone-acrylate copolymers (e.g., UNIQFLOW 6057 from Eucalyptus Chemicals, UK), and one or more other leveling agents that can be used with photocurable resins.

[0041] Sensitizers are substances that can absorb light energy and transfer it to photoinitiators, thereby promoting the reaction efficiency of photoinitiators. Preferred sensitizers include one or more of the following: 2,4-diethylthioxanthonone (e.g., UVS-1331 from China Jiuri New Materials), 2-isopropylthioxanthonone (e.g., UVS-1101 from China Jiuri New Materials), 1-chloro-4-propoxythioxanthonone (e.g., UVS-581 from China Jiuri New Materials), and 2,4-bis(2,4-dimethoxyphenyl)-6-(4-methoxyphenyl)-1,3,5-triazine (e.g., UVS-2171 from China Jiuri New Materials).

[0042] The dispersant is mainly used to ensure uniform dispersion of the hydrazine curing agent particles. The organic groups in the dispersant can adsorb onto the hydrazine groups on the surface of the hydrazine particles, thus allowing the dispersant to stably cover the surface of the hydrazine particles. This ensures uniform dispersion of the hydrazine particles while isolating the hydrazine from the isocyanate groups, increasing the system's room temperature stability. Preferred dispersants include polyester block copolymers and / or polyurethane copolymers; wherein, polyester block copolymers include: polyurethane-modified polyester block copolymers (e.g., DIGIC 690), acidic polyester block copolymers (e.g., DIGIC 688), etc.; polyurethane copolymers include: carboxylated polyurethane copolymers (e.g., BYK-111 from BYK Chemie, Germany), amine-modified polyester polyurethane copolymers (e.g., BYK-190 from BYK Chemie, Germany), phosphate-modified polyurethane block copolymers (e.g., BYK-108 from BYK Chemie, Germany), etc.

[0043] Antioxidants are chemical substances with high antioxidant capacity. When they are present in small amounts in a polymer system, they can delay or inhibit the polymer oxidation process, thereby preventing polymer aging and extending its service life, while reducing yellowing caused by heat treatment. The antioxidants preferably include one or more of the following: N,N'-bis(3,5-di-tert-butyl-4-hydroxyphenylpropionyl)hexamethylenediamine (e.g., BASF Lrganox 1098), dilauryl thiodipropionate (e.g., BASF Lrganox PS800), pentaerythritol tetrakis[β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate] and tris(2,4-di-tert-butylphenyl)phosphite (e.g., BASF Lrganox B225), pentaerythritol tetrakis[β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate] (e.g., BASF Lrganox 1010), octadecyl β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate (e.g., BASF Lrganox 1076), and isooctyl 3,5-di-tert-butyl-4-hydroxyphenylpropionate (e.g., BASF Lrganox 1135).

[0044] A second aspect of the present invention provides a method for preparing the above-described 3D printing resin, comprising: A fourth mixture is obtained by mixing a polyurethane acrylic resin oligomer containing latent isocyanate groups with an active diluent. A photoinitiator, an ultraviolet absorber, and a sensitizer were added to the fourth mixture to obtain the fifth mixture. Adding a dispersant and a curing agent to the fifth mixture yields the sixth mixture; Add leveling agent, defoamer and antioxidant to the sixth mixture to obtain a resin mixture system; The resin mixture is rolled and ground, then filtered to obtain 3D printing resin.

[0045] Optionally, the resin mixture is ground using a three-roll mill to control the particle size of the solid particles in the 3D printing resin to be less than 2 micrometers.

[0046] It is understood that in some alternative embodiments, sensitizers and leveling agents may not be used, i.e., the preparation method of the 3D printing resin includes: A fourth mixture is obtained by mixing a polyurethane acrylic resin oligomer containing latent isocyanate groups with an active diluent. A photoinitiator and an ultraviolet absorber were added to the fourth mixture to obtain the fifth mixture; Adding a dispersant and a curing agent to the fifth mixture yields the sixth mixture; Add defoamer and antioxidant to the sixth mixture to obtain a resin mixture system; The resin mixture is rolled and ground, then filtered to obtain 3D printing resin.

[0047] Example 1 (a) A 3D printing resin The following components are included by mass percentage: Polyurethane acrylic resin oligomers containing latent isocyanate groups: 66.67%; Reactive diluent: 24.80%; Hardener: 4.33%; Photoinitiator: 2.00%; UV absorber: 0.20%; Defoamer: 0.10%; Leveling agent: 0.30%; Sensitizer: 0.20%; Dispersant: 1.00%; Antioxidant: 0.40%.

[0048] (II) Preparation method A 3D printing resin, the preparation method of which includes the following steps: (1) Add 1000g of polyurethane acrylic resin oligomer PTMEG-HMDI-2000, 222g of reactive diluent LMA and 150g of reactive diluent PEGDA to a 3000ml three-necked flask, stir for 90min and mix evenly.

[0049] (2) Continue to add 30 g of photoinitiator phenyl bis(2,4,6-trimethylbenzoyl)phosphine oxide, 3 g of ultraviolet absorber UV-400, and 3 g of sensitizer UVS-581 to the above flask, and continue to stir for 40 min until the mixture is homogeneous.

[0050] (3) Continue to add 15g of dispersant BYK-111 and 65g of adipic hydrazide modified by curing agent to the above flask, and continue stirring for 30min to make the hydrazide dispersed evenly.

[0051] (4) Add 4.5 g of leveling agent BYK-3500, 1.5 g of defoamer Defoamex 820N, and 6 g of antioxidant 1010 to the above flask, and continue stirring for 30 min.

[0052] (5) The mixed resin is ground three times using a three-roll mill to better disperse the hydrazide curing agent. Then, the impurities are removed by filtration to obtain the photo-thermal dual-curing 3D printing resin.

[0053] (6) Test the single-layer exposure time and printing speed on the corresponding printing equipment, and print the corresponding mechanical strips. After the strips are printed, they are cleaned and heat-treated before testing their mechanical properties, see Table 2 for details; and test the viscosity change of the resin at 25℃, see Table 3 for details.

[0054] It is understood that the preparation method of 3D printing resin in the embodiments of this application and the subsequent embodiments is only an exemplary illustration. In actual preparation, the reaction vessel can be adjusted as needed, and the weight of the reactants can be increased or decreased proportionally.

[0055] Example 2 (a) A 3D printing resin The following components are included by mass percentage: Polyurethane acrylic resin oligomers containing latent isocyanate groups: 60%; Reactive diluent: 29.73%; Hardener: 5.00%; Photoinitiator: 3.00%; UV absorber: 0.13%; Defoamer: 0.07%; Leveling agent: 0.40%; Sensitizer: 0.20%; Dispersant: 1.20%; Antioxidant: 0.27%.

[0056] (II) Preparation method A 3D printing resin, the preparation method of which includes the following steps: (1) Add 900g of polyurethane acrylic resin oligomer PPG-HMDI-2000, 146g of reactive diluent DEGDMA, and 300g of reactive diluent IBOA to a 3000ml three-necked flask, stir for 90min and mix evenly.

[0057] (2) Continue to add 45g of photoinitiator 2,4,6-trimethylbenzoylphosphonate ethyl ester, 2g of ultraviolet absorber UV-P, and 3g of sensitizer UVS-581 to the above flask, and continue stirring for 40min to mix evenly.

[0058] (3) Continue to add 18 grams of dispersant BYK-190 and 75 grams of curing agent modified surfactant sebacyl hydrazine to the above flask, and continue stirring for 30 minutes to make the hydrazine dispersed evenly.

[0059] (4) Add 6 g of leveling agent BYK-3500, 1 g of defoamer TEGO Airex 900, and 4 g of antioxidant lrganox 1010 to the above flask and continue stirring for 30 min.

[0060] (5) Grind the mixed resin three times using a three-roll mill to better disperse the hydrazide curing agent, and then filter to remove impurities.

[0061] (6) Test the single-layer exposure time and printing speed on the corresponding printing equipment, and print the corresponding mechanical strips. After the strips are printed, they are cleaned and heat-treated before testing their mechanical properties, see Table 2 for details; and test the viscosity change of the resin at 25℃, see Table 3 for details.

[0062] Example 3 (a) A 3D printing resin The following components are included by mass percentage: Polyurethane acrylic resin oligomers containing latent isocyanate groups: 50.00%; Reactive diluent: 40.47%; Hardener: 3.67%; Photoinitiator: 4.00%; UV absorber: 0.13%; Defoamer: 0.13%; Leveling agent: 0.33%; Sensitizer: 0.33%; Dispersant: 0.67%; Antioxidant: 0.27%.

[0063] (II) Preparation method A 3D printing resin, the preparation method of which includes the following steps: (1) Add 750g of polyurethane acrylic resin oligomer PPG-TDI-1000, 150g of reactive diluent ACMO, and 457g of reactive diluent LA to a 3000ml three-necked flask, stir for 90min, and mix evenly.

[0064] (2) Continue to add 60 g of photoinitiator ethyl 2,4,6-trimethylbenzoylphosphonate, 2 g of UV absorber UV-P, and 5 g of sensitizer UVS-1101 to the above flask, and continue stirring for 40 min to mix evenly.

[0065] (3) Continue to add 10 g of dispersant BYK-190 and 55 g of heptane dihydrazide, which is a curing agent and modified surfactant, to the above flask, and continue to stir for 30 min to make the hydrazide dispersed evenly.

[0066] (4) Add 5 g of leveling agent BYK-3500, 2 g of defoamer TEGO Airex 900, and 4 g of antioxidant lrganox PS800 to the above flask, and continue stirring for 30 min.

[0067] (5) Grind the mixed resin three times using a three-roll mill to better disperse the hydrazide curing agent, and then filter to remove impurities.

[0068] (6) Test the single-layer exposure time and printing speed on the corresponding printing equipment, and print the corresponding mechanical strips. After the strips are printed, they are cleaned and heat-treated before testing their mechanical properties, see Table 2 for details; and test the viscosity change of the resin at 25℃, see Table 3 for details.

[0069] Example 4 (a) A 3D printing resin The following components are included by mass percentage: Polyurethane acrylic resin oligomers containing latent isocyanate groups: 70.00%; Reactive diluent: 20.07%; Hardener: 4.67%; Photoinitiator: 3.00%; UV absorber: 0.13%; Defoamer: 0.13%; Leveling agent: 0.20%; Sensitizer: 0.20%; Dispersant: 1.40%; Antioxidant: 0.20%.

[0070] (II) Preparation method A 3D printing resin, the preparation method of which includes the following steps: (1) Add 600g of polyurethane acrylic resin oligomer PTMEG-HMDI-3000, 450g of polyurethane acrylic resin oligomer PPG-IPDI-1000, 120g of reactive diluent DEGDMA, and 181g of reactive diluent LMA to a 3000ml three-necked flask, stir for 90min and mix evenly.

[0071] (2) Continue to add 15 g of photoinitiator 2-isopropylthioxanthone (2,4 isomer mixture), 30 g of ethyl 2,4,6-trimethylbenzoylphosphonate, 2 g of UV absorber UV-400, and 3 g of sensitizer UVS-581 to the above flask, and continue stirring for 40 min until the mixture is homogeneous.

[0072] (3) Continue to add 21 g of dispersant BYK-190 and 70 g of adipic hydrazide (a curing agent modified surfactant) to the above flask, and continue stirring for 30 min to make the hydrazide dispersed evenly.

[0073] (4) Add 3 g of leveling agent BYK-377, 2 g of defoamer UNIQ®FOAM 7032, and 3 g of antioxidant lrganox1076 to the above flask and continue stirring for 30 min.

[0074] (5) Grind the mixed resin three times using a three-roll mill to better disperse the hydrazide curing agent, and then filter to remove impurities.

[0075] (6) Test the single-layer exposure time and printing speed on the corresponding printing equipment, and print the corresponding mechanical strips. After the strips are printed, they are cleaned and heat-treated before testing their mechanical properties, see Table 2 for details; and test the viscosity change of the resin at 25℃, see Table 3 for details.

[0076] Example 5 (a) A 3D printing resin The following components are included by mass percentage: Polyurethane acrylic resin oligomers containing latent isocyanate groups: 48.00%; Reactive diluent: 45.07%; Hardener: 3.00%; Photoinitiator: 2.00%; UV absorber: 0.13%; Defoamer: 0.20%; Leveling agent: 0.20%; Sensitizer: 0.20%; Dispersant: 1.00%; Antioxidant: 0.20%.

[0077] (II) Preparation method A 3D printing resin, the preparation method of which includes the following steps: (1) Add 720g of polyurethane acrylic resin oligomer PTMEG-IPDI-1000, 196g of reactive diluent DEGDMA, 180g of reactive diluent IBOA, and 300g of reactive diluent LMA to a 3000ml three-necked flask and stir for 90min until well mixed.

[0078] (2) Continue to add 30 g of photoinitiator phenyl bis(2,4,6-trimethylbenzoyl)phosphine oxide, 2 g of UV absorber UV-327, and 3 g of sensitizer UVS-1101 to the above flask, and continue stirring for 40 min until the mixture is homogeneous.

[0079] (3) Continue to add 15g of dispersant BYK-190 and 45g of curing agent modified surfactant sebacyl hydrazine to the above flask, and continue stirring for 30min to make the hydrazine dispersed evenly.

[0080] (4) Add 3 g of leveling agent BYK-3500, 3 g of defoamer BYK-024, and 3 g of antioxidant lrganox1098 to the above flask and continue stirring for 30 min.

[0081] (5) Grind the mixed resin three times using a three-roll mill to better disperse the hydrazide curing agent, and then filter to remove impurities.

[0082] (6) Test the single-layer exposure time and printing speed on the corresponding printing equipment, and print the corresponding mechanical strips. After the strips are printed, they are cleaned and heat-treated before testing their mechanical properties, see Table 2 for details; and test the viscosity change of the resin at 25℃, see Table 3 for details.

[0083] Example 6 (a) A 3D printing resin The following components are included by mass percentage: Polyurethane acrylic resin oligomers containing latent isocyanate groups: 66.67%; Reactive diluent: 23.86%; Hardener: 5.00%; Photoinitiator: 2.40%; UV absorber: 0.20%; Defoamer: 0.07%; Leveling agent: 0.20%; Sensitizer: 0.20%; Dispersant: 1.20%; Antioxidant: 0.20%.

[0084] (II) Preparation method A 3D printing resin, the preparation method of which includes the following steps: (1) Add 600g of polyurethane acrylic resin oligomer PPG-HDI-2000, 400g of polyurethane acrylic resin oligomer PTMEG-IPDI-1000, 138g of reactive diluent TEGDMA, and 220g of reactive diluent IBOA to a 3000ml three-necked flask, stir for 90min and mix evenly.

[0085] (2) Continue to add 36 g of photoinitiator ethyl 2,4,6-trimethylbenzoylphosphonate, 3 g of UV absorber UV-P, and 3 g of sensitizer UVS-581 to the above flask, and continue stirring for 40 min until the mixture is homogeneous.

[0086] (3) Continue to add 18 grams of dispersant DIG690 and 75 grams of isophthalic acid dihydrazide modified by curing agent to the above flask, and continue stirring for 30 minutes to make the hydrazide dispersed evenly.

[0087] (4) Add 3 g of leveling agent BYK-3500, 1 g of defoamer TEGO Airex 920, and 3 g of antioxidant lrganox B225 to the above flask, and continue stirring for 30 min.

[0088] (5) Grind the mixed resin three times using a three-roll mill to better disperse the hydrazide curing, and then filter to remove impurities.

[0089] (6) Test the single-layer exposure time and printing speed on the corresponding printing equipment, and print the corresponding mechanical strips. After the strips are printed, they are cleaned and heat-treated before testing their mechanical properties, see Table 2 for details; and test the viscosity change of the resin at 25℃, see Table 3 for details.

[0090] Table 2. Performance of the 3D printing resins prepared in Examples 1-6

[0091] Table 3. Viscosity changes of the 3D printing resins prepared in Examples 1-6 at 25°C.

[0092] As can be seen from Table 2, the 3D printing resins prepared in Examples 1-6 have excellent mechanical strength, elongation at break, resilience and flexural strength.

[0093] As can be seen from Table 3, the viscosity of the 3D printing resins prepared in Examples 1-6 does not change by more than 20% after 180 days at room temperature, which can meet the long-term requirements of 3D printing.

[0094] It will be readily understood by those skilled in the art that the above-described advantageous methods can be freely combined and superimposed without conflict. The above are merely preferred embodiments of this application and are not intended to limit this application. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of this application should be included within the protection scope of this application. The above are merely preferred embodiments of this application. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the technical principles of this application, and these improvements and modifications should also be considered within the protection scope of this application.

Claims

1. A 3D printing resin, characterized in that, It comprises the following components by mass percentage: Polyurethane acrylic resin oligomers containing latent isocyanate groups: 40%-70%; Reactive diluent: 15%-50%; Hardener: 3%-8%; Photoinitiator: 0.5%-10%; UV absorber: 0.1%-1.2%; Defoamer: 0.05%-0.2%; Dispersant: 0.5%-5%; Antioxidant: 0.1%-0.5%; The curing agent is a solid acylhydrazine compound with surface-modified surfactant.

2. The 3D printing resin according to claim 1, characterized in that, The 3D printing resin comprises the following components by weight percentage: Polyurethane acrylic resin oligomers containing latent isocyanate groups: 40%-70%; Reactive diluent: 15%-50%; Hardener: 3%-5%; Photoinitiator: 2%-4%; UV absorber: 0.1%-0.2%; Defoamer: 0.05%-0.2%; Dispersant: 0.5%-1.5%; Antioxidant: 0.2%-0.4%.

3. The 3D printing resin according to claim 1 or 2, characterized in that, The 3D printing resin also includes the following components in weight percentage: Leveling agent: 0.2%-0.4%; Sensitizer: 0.2%-1.5%.

4. The 3D printing resin according to claim 1, characterized in that, The polyurethane acrylic resin oligomer containing latent isocyanate groups is prepared by the following method: The isocyanate and organotin catalyst were mixed to obtain the first mixture; A polyol was added to the first mixture, and the mixture was reacted at 58℃-62℃ for 1.5h-2.5h to obtain the second mixture. The second mixture was cooled to 30°C-40°C, and a polymerization inhibitor and a capping agent were added to obtain a third mixture; The third mixture is heated to 48℃-52℃ and reacted for 1.5h-2.5h. After the reaction is completed, the mixture is cooled and discharged to obtain the polyurethane acrylic resin oligomer containing latent isocyanate groups.

5. The 3D printing resin according to claim 4, characterized in that, The 3D printing resin must meet at least one of the following conditions: The isocyanate is a difunctional isocyanate; The polyol is a polyether polyol or a polyester polyol; The organotin catalyst is dibutyltin dilaurate and / or stannous octoate; The polymerization inhibitor is p-hydroxyanisole; The capping agent is tert-butylaminoethyl methacrylate.

6. The 3D printing resin according to claim 1, characterized in that, The reactive diluent includes low molecular weight compounds containing acrylate groups and / or methacrylate groups.

7. The 3D printing resin according to claim 1 or 6, characterized in that, The active diluent includes one or more of the following: acrylamide, dipropylene glycol diacrylate, tripropylene glycol diacrylate, diethylene glycol dimethacrylate, tri(2-hydroxyethyl) isocyanurate triacrylate, laurate, laurate methacrylate, polyethylene glycol diacrylate, polyethylene glycol dimethacrylate, and isoborneol methacrylate.

8. The 3D printing resin according to claim 1, characterized in that, The curing agent includes surface-modifying surfactants such as adipamide, heptane dihydrazide, polyethylene glycol dihydrazide, sebacate dihydrazide, isophthalic acid dihydrazide, dodecane dicarboxylic acid dihydrazide, and / or isophthalic acid dihydrazide.

9. The 3D printing resin according to claim 1 or 8, characterized in that, The surfactant is adsorbed onto the surface of the solid acylhydrazine particles by physical adsorption.

10. The 3D printing resin according to claim 1, characterized in that, The photoinitiator absorbs ultraviolet and / or visible light to generate free radicals that initiate the polymerization of acrylate groups.

11. The 3D printing resin according to claim 1 or 10, characterized in that, The photoinitiator includes one or more of the following: phenyl bis(2,4,6-trimethylbenzoyl)phosphine oxide, ethyl 2,4,6-trimethylbenzoylphosphonate, diphenyl(2,4,6-trimethylbenzoyl)phosphine oxide, 1-hydroxycyclohexylphenyl ketone, 2-isopropylthioxanthone (a mixture of 2,4 isomers), and 2-methyl-1-[4-methylthiophenyl]-2-morpholino-1-propanone.

12. The 3D printing resin according to claim 1, characterized in that, The ultraviolet absorber includes one or more of benzotriazoles, triazines, anthocyanins, and aniline black.

13. The 3D printing resin according to claim 3, characterized in that, The defoamer includes one or more of the following: polysiloxane-polyether block copolymer, hydroxyl-terminated polydimethylsiloxane, hydrophobic silica-modified polydimethylsiloxane, polyethylene glycol-polypropylene glycol block copolymer, and mineral oil-based complex. The leveling agent includes one or more of the following: fluorinated polyacrylate, polyether-modified polysiloxane, polyether-modified polydimethylsiloxane, polyester-modified hydroxyl-functionalized polydimethylsiloxane, and organosilicon-acrylate copolymer. The sensitizer includes one or more of 2,4-diethylthioxanthanone, 2-isopropylthioxanthanone, 1-chloro-4-propoxythioxanthanone, and 2,4-bis(2,4-dimethoxyphenyl)-6-(4-methoxyphenyl)-1,3,5-triazine.

14. The 3D printing resin according to claim 1, characterized in that, The dispersant includes polyester block copolymers and / or polyurethane copolymers.

15. The 3D printing resin according to claim 14, characterized in that, The polyester block copolymers include: polyurethane-modified polyester block copolymers and / or acidic polyester block copolymers; the polyurethane copolymers include: carboxylated polyurethane copolymers, amine-modified polyester polyurethane copolymers, and / or phosphate-modified polyurethane block copolymers.

16. The 3D printing resin according to claim 1, characterized in that, The antioxidants include one or more of N,N'-bis(3,5-di-tert-butyl-4-hydroxyphenylpropionyl)hexamethylenediamine, dilaurate thiodipropionate, pentaerythritol tetrakis[β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate] and tris(2,4-di-tert-butylphenyl)phosphite, pentaerythritol tetrakis[β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate], octadecyl β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate, and isooctyl 3,5-di-tert-butyl-4-hydroxyphenylpropionate.

17. A method for preparing a 3D printing resin, characterized in that, The method for preparing the 3D printing resin according to any one of claims 1-16 includes: The polyurethane acrylic resin oligomer containing latent isocyanate groups is mixed with the reactive diluent to obtain a fourth mixture; The photoinitiator and the ultraviolet absorber are added to the fourth mixture to obtain the fifth mixture; Adding the dispersant and the curing agent to the fifth mixture yields a sixth mixture; Add the defoamer and the antioxidant to the sixth mixture to obtain a resin mixture system; The resin mixture is rolled and milled, and then filtered to obtain the 3D printing resin.

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