A 3D printing method of a heat pre-cured two-component 3D printing photosensitive resin composition

Abstract

The application provides a 3D printing method of a heat pre-cured two-component 3D printing photosensitive resin composition, the composition comprising the following components by mass percentage: photocurable resin monomer and / or oligomer: 20-40%; photoinitiator: 3-10%; resin prepolymer containing a heat curing component: 40-70%; chain extender: 7-10%; the 3D printing method comprises the following steps: step (1): weighing each component according to the formula, adding into a mixing container, stirring uniformly to obtain a mixture; step (2): placing the mixture obtained in step (1) into an oven, and heat treating at 70-120 DEG C for 10-30 minutes to perform heat pre-curing, thereby obtaining a solid printing piece; step (3): performing 3D printing on the solid printing piece obtained in step (2) under ultraviolet light irradiation; and step (4): heat curing the solid printing piece in step (3) to obtain a 3D printing product.

Description

Technical Field

[0001] This invention relates to the field of 3D printing technology, and more specifically, to a 3D printing method for a thermally pre-cured two-component 3D printing photosensitive resin composition. Background Technology

[0002] 3D printing is a rapid prototyping technology that uses photosensitive resin to solidify and form a specific shape. It can quickly, accurately, and cost-effectively obtain workpieces with various structures, and has advantages such as high printing accuracy, high surface smoothness, and fast forming speed.

[0003] US2015 / 036902 discloses a multi-curing photosensitive resin material, which is a high-performance 3D printing material obtained by curing end-capped polyurethane under ultraviolet light, then decapsulating and heating to rearrange it.

[0004] CN112724605 discloses a dual-phase separation type continuous 3D printing high-precision photosensitive resin composition. This invention abandons the concept of layers; in photopolymerization 3D printing, continuous irradiation with ultraviolet light causes the liquid photosensitive resin to transform into a solid. However, due to the limited penetration of ultraviolet light, the parts that cannot be penetrated by ultraviolet light will not solidify, resulting in uneven curing of the product, which is particularly noticeable for thicker samples. In addition, while ultraviolet light initiates the polymerization reaction, it also destroys the carbon-carbon double bonds in the material, causing material aging and degradation. These defects limit the promotion and application of photopolymerization technology.

[0005] CN106947034A discloses a heat-curable photosensitive resin for 3D printing, its preparation method, and its applications. The photosensitive resin comprises: a prepolymer, a diluent, a photoinitiator, and a thermal initiator, wherein the thermal initiator has a decomposition temperature greater than or equal to 100°C when its half-life is one hour; the weight parts of each component are as follows: prepolymer 50-70 parts, diluent 30-50 parts, photoinitiator 1-5 parts, and thermal initiator 0.5-5 parts. After photocuring and 3D printing, the photosensitive resin of this invention can be heat-cured in a stable constant-temperature oven, such as an oven. Summary of the Invention

[0006] To overcome the shortcomings of existing technologies, this invention provides a 3D printing method for a thermally pre-cured two-component photosensitive resin composition. The method involves first heating the resin in an oven for thermal pre-curing, then using photocuring to form a solid printed part, followed by supplementary photocuring, and finally thermal curing to obtain the product. The introduction of the first-step thermal pre-curing process improves the printing success rate of the photocuring step.

[0007] The technical solution of the present invention is as follows: A 3D printing method for a thermally precured two-component 3D printing photosensitive resin composition, wherein the thermally precured two-component 3D printing photosensitive resin composition comprises the following components in the indicated mass percentages:

[0008] Photocurable resin monomers and / or oligomers: 20%-40%;

[0009] Photoinitiator: 3%-10%;

[0010] Resin prepolymers containing thermosetting components: 40%-70%;

[0011] Chain extender: 7%-10%;

[0012] The resin prepolymer containing thermosetting components is a polyether urethane acrylate with active end groups blocked by a nucleophilic reagent, and its side chains are 2, 3 or multifunctional; the nucleophilic reagent is a small molecule reagent containing active amino or hydroxyl groups.

[0013] The 3D printing method includes the following steps:

[0014] Step (1): Weigh each component according to the formula, add them to a mixing container, stir evenly to obtain a mixture;

[0015] Step (2): Place the mixture obtained in step (1) into an oven and keep it at 70-120℃ for 10-30 minutes to perform heat pre-curing and obtain a liquid resin that has been heat pre-cured.

[0016] Step (3): The liquid resin obtained in step (2) after heat pre-curing is 3D printed under ultraviolet light to obtain a sample;

[0017] Step (4): The sample obtained in step (3) is subjected to additional ultraviolet light curing to obtain a solid-state printed part;

[0018] Step (5): Immerse the solid-state printed part described in step (4) in a heat transfer medium at 90-130℃ for 90-180 minutes to perform heat curing treatment and obtain the 3D printed product.

[0019] The photocurable resin monomers and / or oligomers are acrylate monomers and / or their oligomers.

[0020] The photocurable resin monomer contains one or any mixture of hydroxyethyl methacrylate, hydroxypropyl methacrylate, isobornyl methacrylate, and caprolactone acrylate.

[0021] The chain extender is a diol, diamine, or alkanolamine with a molecular weight of less than 800.

[0022] The thermal initiator is preferably one or more of dicumyl peroxide, di-tert-butyl peroxide, tert-butyl peroxide, cumyl hydroperoxide, and tert-butyl hydroperoxide.

[0023] The photoinitiator is one or more of 1-hydroxycyclohexylphenyl ketone, 2,4,6-trimethylbenzoyl-phosphorus dioxide, and 2-ethyloctyl-4-dimethylaminobenzoate.

[0024] Step (4) further includes cleaning the solid-state printed part in ethanol, isopropanol or 70% ethanol aqueous solution.

[0025] In step (4), the thermosetting process involves immersing the solid printed part obtained in step (3) in a heat transfer medium at 90-130°C for 90-180 minutes.

[0026] The heat transfer medium is selected from one or any mixture of methyl silicone oil, ethyl silicone oil, phenyl silicone oil, methyl hydrogen silicone oil, ethyl hydrogen silicone oil, methyl ethoxy silicone oil, and methyl trifluoropropyl silicone oil.

[0027] In this invention, the thermosetting two-component 3D printing photosensitive resin composition comprises photocurable resin monomers and / or oligomers, a photoinitiator, and resin oligomers containing thermosetting components and chain extenders. The thermosetting resin prepolymer is a polyether urethane acrylate with active end groups blocked by a nucleophilic reagent, and the photocurable resin monomers and / or oligomers are acrylate monomers and / or their oligomers, acting as a diluent.

[0028] In this invention, the thermally pre-cured two-component 3D printing photosensitive resin composition is first thermally pre-cured at 70-120℃ for 10-30 minutes, allowing the chain extender to precede the modified acrylate component and the acrylate chain agent, forming a loose network structure. Then, 3D printing is performed under ultraviolet light irradiation. Under ultraviolet light irradiation, the photocurable resin monomers and / or oligomers and the resin prepolymer containing the thermally curable component, i.e., the double bonds in the acrylic resin component and the modified acrylic resin component, are broken, initiating a polymerization reaction to form a tight network structure, transforming the composition from a liquid to a solid state. Then, heating curing is performed. During this process, the chain extender further connects the side chain groups of the modified acrylic resin component and the acrylic component, thereby further polymerization to form a denser and tighter photo-thermal interpenetrating polymer network structure. Compared to traditional photocurable products, the thermal pre-curing treatment before heating improves the success rate of part production and increases the reaction conversion rate of the thermal curing step.

[0029] The present invention relates to a thermally pre-cured two-component 3D printing photosensitive resin composition and its 3D printing method. In the present invention, the immersion liquid is introduced into the thermal curing process to assist curing, which not only improves the thermal curing conditions and increases the thermal curing reaction conversion rate, but also improves the deformation caused by the thermal curing process and avoids the deformation of complex structure samples due to gravity factors. Detailed Implementation

[0030] To make the objectives, technical solutions, and effects of this invention clearer, the invention will be further described below in conjunction with specific embodiments. It should be understood that the specific embodiments described herein are for illustrative purposes only and are not intended to limit the scope of the invention.

[0031] Example 1: A thermosetting two-component 3D printing photosensitive resin composition, comprising the following components by weight percentage: photocurable resin monomers and / or oligomers: 24%; photoinitiator: 6.5%; resin prepolymer containing thermosetting components: 40%-70%; chain extender: 10%; wherein the resin prepolymer containing thermosetting components is a polyether urethane acrylate with active end groups blocked by a nucleophilic reagent. The photocurable resin monomer is an acrylate monomer. The photocurable resin monomer is selected from hydroxyethyl methacrylate. The polyether urethane acrylate has a functionality of 2; the nucleophilic reagent is a small molecule reagent containing active amino or hydroxyl groups. The chain extender is a diamine with a molecular weight less than 800. The thermosetting initiator is preferably dicumyl peroxide. The photoinitiator is 1-hydroxycyclohexylphenyl ketone.

[0032] The 3D printing method for the above-mentioned thermally precured two-component 3D printing photosensitive resin composition includes the following steps:

[0033] The 3D printing method includes the following steps:

[0034] Step (1): Weigh each component according to the formula, add them to a mixing container, stir evenly to obtain a mixture;

[0035] Step (2): Place the mixture obtained in step (1) into an oven and keep it at 70-120℃ for 10-30 minutes to perform heat pre-curing and obtain a liquid resin that has been heat pre-cured.

[0036] Step (3): The liquid resin obtained in step (2) after heat pre-curing is 3D printed under ultraviolet light to obtain a sample;

[0037] Step (4): The sample obtained in step (3) is subjected to additional ultraviolet light curing to obtain a solid-state printed part;

[0038] Step (5): The solid printed part described in step (4) is heat-cured, that is, immersed in the heat transfer medium methyl silicone oil and methyl ethoxy silicone oil at 120°C for 120 minutes to obtain the 3D printed product.

[0039] Example 2: A thermosetting two-component 3D printing photosensitive resin composition, comprising the following components by weight percentage: photocurable resin monomers and / or oligomers: 20%; photoinitiator: 8%; resin prepolymer containing thermosetting components: 64%; chain extender: 8%; wherein the resin prepolymer containing thermosetting components is a polyether urethane acrylate with active end groups blocked by a nucleophilic reagent. The photocurable resin monomer oligomer is an acrylate monomer oligomer. The photocurable resin monomer is selected from a mixture of hydroxypropyl methacrylate and caprolactone acrylate. The polyether urethane acrylate has a functionality of 3; the nucleophilic reagent is a small molecule reagent containing active amino or hydroxyl groups. The chain extender is a diol with a molecular weight less than 800. The thermosetting initiator is preferably a mixture of di-tert-butyl peroxide and tert-butyl peroxide. The photoinitiator is 1-hydroxycyclohexylphenyl ketone.

[0040] The 3D printing method for the above-mentioned thermally precured two-component 3D printing photosensitive resin composition includes the following steps:

[0041] The 3D printing method includes the following steps:

[0042] Step (1): Weigh each component according to the formula, add them to a mixing container, stir evenly to obtain a mixture;

[0043] Step (2): Place the mixture obtained in step (1) into an oven and keep it at 120°C for 10 minutes to perform heat pre-curing and obtain a liquid resin that has been heat pre-cured.

[0044] Step (3): The liquid resin obtained in step (2) after heat pre-curing is 3D printed under ultraviolet light to obtain a sample;

[0045] Step (4): The sample obtained in step (3) is subjected to additional ultraviolet light curing to obtain a solid-state printed part;

[0046] Step (5): The solid printed part described in step (4) is heat-cured, that is, immersed in methyl ethoxy silicone oil at 130°C for 90 minutes to obtain the 3D printed product.

[0047] Example 3: A thermosetting two-component 3D printing photosensitive resin composition, comprising the following components by weight percentage: photocurable resin monomers and / or oligomers: 40%; photoinitiator: 6.5%; resin prepolymer containing thermosetting components: 46.5%; chain extender: 7%; wherein the resin prepolymer containing thermosetting components is a polyether urethane acrylate with active end groups blocked by a nucleophilic reagent. The photocurable resin monomer is an acrylate monomer. The photocurable resin monomer is selected from a mixture of hydroxyethyl methacrylate and caprolactone acrylate. The polyether urethane acrylate has a functionality of 2; the nucleophilic reagent is a small molecule reagent containing active amino or hydroxyl groups. The chain extender is an alkanolamine with a molecular weight less than 800. The thermosetting initiator is preferably dicumyl peroxide. The photoinitiator is 1-hydroxycyclohexylphenyl ketone.

[0048] The 3D printing method for the above-mentioned thermally precured two-component 3D printing photosensitive resin composition includes the following steps:

[0049] The 3D printing method includes the following steps:

[0050] Step (1): Weigh each component according to the formula, add them to a mixing container, stir evenly to obtain a mixture;

[0051] Step (2): Place the mixture obtained in step (1) into an oven and keep it at 70°C for 30 minutes to perform heat pre-curing and obtain a liquid resin that has been heat pre-cured.

[0052] Step (3): The liquid resin obtained in step (2) after heat pre-curing is 3D printed under ultraviolet light to obtain a sample;

[0053] Step (4): The sample obtained in step (3) is subjected to additional ultraviolet light curing to obtain a solid-state printed part;

[0054] Step (5): The solid-state printed part described in step (4) is heat-cured, that is, immersed in methyl trifluoropropyl silicone oil at 100°C for 120 minutes to obtain the 3D printed product.

[0055] Example 4: A thermosetting two-component 3D printing photosensitive resin composition, comprising the following components by weight percentage: photocurable resin monomers and / or oligomers: 30%; photoinitiator: 6%; resin prepolymer containing thermosetting components: 55%; chain extender: 9%; wherein the resin prepolymer containing thermosetting components is a polyether urethane acrylate with active end groups blocked by a nucleophilic reagent. The photocurable resin monomer is an acrylate monomer. The photocurable resin monomer is selected from a mixture of hydroxypropyl methacrylate and isobornyl methacrylate. The polyether urethane acrylate has a functionality of 2; the nucleophilic reagent is a small molecule reagent containing active amino or hydroxyl groups. The chain extender is a diol with a molecular weight less than 800. The thermosetting initiator is preferably dicumyl peroxide. The photoinitiator is 1-hydroxycyclohexylphenyl ketone.

[0056] The 3D printing method for the above-mentioned thermally precured two-component 3D printing photosensitive resin composition includes the following steps:

[0057] The 3D printing method includes the following steps:

[0058] Step (1): Weigh each component according to the formula, add them to a mixing container, stir evenly to obtain a mixture;

[0059] Step (2): Place the mixture obtained in step (1) into an oven and keep it at 100°C for 20 minutes to perform heat pre-curing and obtain a liquid resin that has been heat pre-cured.

[0060] Step (3): The liquid resin obtained in step (2) after heat pre-curing is 3D printed under ultraviolet light to obtain a sample;

[0061] Step (4): The sample obtained in step (3) is subjected to additional ultraviolet light curing to obtain a solid-state printed part;

[0062] Step (5): The solid printed part described in step (4) is heat-cured, that is, immersed in phenyl silicone oil at 90°C for 180 minutes to obtain the 3D printed product.

[0063] Example 5: A thermosetting two-component 3D printing photosensitive resin composition, comprising the following components by weight percentage: photocurable resin monomers and / or oligomers: 20%; photoinitiator: 3%; resin prepolymer containing thermosetting components: 70%; chain extender: 7%; wherein the thermocurable resin prepolymer is a polyether urethane acrylate with active end groups blocked by a nucleophilic reagent, having a functionality of 2; the nucleophilic reagent is a small molecule reagent containing active amino or hydroxyl groups. The photocurable resin monomer oligomer is an acrylate monomer oligomer. The photocurable resin monomer is selected from hydroxyethyl methacrylate. The chain extender is a diamine with a molecular weight less than 800. The thermosetting initiator is preferably dicumyl peroxide. The photoinitiator is 1-hydroxycyclohexylphenyl ketone.

[0064] The 3D printing method for the above-mentioned thermally precured two-component 3D printing photosensitive resin composition includes the following steps:

[0065] The 3D printing method includes the following steps:

[0066] Step (1): Weigh each component according to the formula, add them to a mixing container, stir evenly to obtain a mixture;

[0067] Step (2): Place the mixture obtained in step (1) into an oven and keep it at 120°C for 10 minutes to perform heat pre-curing and obtain a liquid resin that has been heat pre-cured.

[0068] Step (3): The liquid resin obtained in step (2) after heat pre-curing is 3D printed under ultraviolet light to obtain a sample;

[0069] Step (4): The sample obtained in step (3) is subjected to additional ultraviolet light curing to obtain a solid-state printed part;

[0070] Step (5): The solid printed part described in step (4) is heat-cured, that is, immersed in a heat transfer medium at 100°C for 180 minutes to obtain the 3D printed product.

[0071] Example 6: A thermally precured two-component 3D printing photosensitive resin composition, comprising the following components by weight percentage: photocurable resin monomers and / or oligomers: 40%; photoinitiator: 5%; thermal initiator: 5%; resin prepolymer containing thermally curable components: 40%; chain extender: 10%; wherein the resin prepolymer containing thermally curable components is a polyether urethane acrylate with active end groups blocked by a nucleophilic reagent, and its functionality is 2; the nucleophilic reagent is a small molecule reagent containing active amino or hydroxyl groups. The photocurable resin monomer oligomer is an acrylate monomer oligomer. The photocurable resin monomer is selected from hydroxyethyl methacrylate. The chain extender is a diamine with a molecular weight less than 800. The thermal initiator is preferably dicumyl peroxide. The photoinitiator is 1-hydroxycyclohexylphenyl ketone.

[0072] The 3D printing method for the above-mentioned thermally precured two-component 3D printing photosensitive resin composition includes the following steps:

[0073] The 3D printing method includes the following steps:

[0074] Step (1): Weigh each component according to the formula, add them to a mixing container, stir evenly to obtain a mixture;

[0075] Step (2): Place the mixture obtained in step (1) into an oven and keep it at 70°C for 30 minutes to perform heat pre-curing and obtain a liquid resin that has been heat pre-cured.

[0076] Step (3): The liquid resin obtained in step (2) after heat pre-curing is 3D printed under ultraviolet light to obtain a sample;

[0077] Step (4): The sample obtained in step (3) is subjected to additional ultraviolet light curing to obtain a solid-state printed part;

[0078] Step (5): The solid printed part described in step (4) is heat-cured, that is, immersed in ethyl silicone oil at 130°C for 90 minutes to obtain the 3D printed product.

[0079] Comparative Examples 1-3

[0080] The thermally precured two-component 3D printing photosensitive resin compositions described in Examples 1-3 were respectively printed using the following 3D printing methods:

[0081] Step (1): Weigh each component according to the formula, add them to a mixing container, stir evenly to obtain a mixture;

[0082] Step (2): The mixture obtained in step (1) is photocured using a photocuring 3D printing device to form a solid printed part;

[0083] Step (3): Clean the surface of the solid print obtained in step (2) with ethanol solution.

[0084] To further test the performance of the thermally precured two-component 3D printing photosensitive resin composition described in this invention, the performance of the thermally precured two-component 3D printing photosensitive resin compositions prepared in Examples 1-3 and Comparative Examples 1-3 was tested.

[0085] The success rates of the packaging of Comparative Examples 1-3 and Comparative Examples 1-3 are recorded in Table 1.

[0086]

[0087] Viscosity was tested according to GB / T10248-2008 Viscosity Measurement Method; monomer residue was tested according to gas chromatography-mass spectrometry in SN_T3342-2012 Determination of Residual Monomer Content in Acrylic Resins; Vickers hardness was tested according to the test methods in Part 1 of GB / T 4340.1-2009 Vickers Hardness; flexural modulus and flexural strength were tested according to YY0710-2009 Dental Polymer-Based Crown and Bridge Materials.

[0088] The test results are shown in Table 1:

[0089]

[0090] The above description, in conjunction with specific preferred embodiments, provides a further detailed explanation of the present invention and should not be construed as limiting the specific implementation of the invention to these descriptions. For those skilled in the art, the architectural form of this invention can be flexibly varied without departing from its conceptual framework, leading to the derivation of a series of products. Any simple deductions or substitutions should be considered as falling within the patent protection scope defined by the submitted claims.

Claims

1. A 3D printing method for a thermally pre-cured two-component 3D printing photosensitive resin composition, characterized in that, The thermally precured two-component 3D printing photosensitive resin composition comprises the following components by weight percentage: Photocurable resin monomers and / or oligomers: 20%-40%; Photoinitiator: 3%-10%; Resin prepolymers containing thermosetting components: 40%-70%; Chain extender: 7%-10%; The resin prepolymer containing thermosetting components is a polyether urethane acrylate with active end groups blocked by a nucleophilic reagent, and its side chains are 2, 3 or multifunctional; the nucleophilic reagent is a small molecule reagent containing active amino or hydroxyl groups. The 3D printing method includes the following steps: Step (1): Weigh each component according to the formula, add them to a mixing container, stir evenly to obtain a mixture; Step (2): Place the mixture obtained in step (1) into an oven and keep it at 70-120℃ for 10-30 minutes to perform heat pre-curing and obtain a liquid resin that has been heat pre-cured. Step (3): The liquid resin obtained in step (2) after heat pre-curing is 3D printed under ultraviolet light to obtain a sample; Step (4): The sample obtained in step (3) is subjected to additional ultraviolet light curing to obtain a solid-state printed part; Step (5): Immerse the solid-state printed part described in step (4) in a heat transfer medium at 90-130℃ for 90-180 minutes to perform heat curing treatment and obtain the 3D printed product.

2. The 3D printing method of the thermally pre-cured two-component 3D printing photosensitive resin composition according to claim 1, characterized in that: The photocurable resin monomers and / or oligomers are acrylate monomers and / or their oligomers.

3. The 3D printing method of the thermally pre-cured two-component 3D printing photosensitive resin composition according to claim 2, characterized in that: The photocurable resin monomer contains one or any mixture of hydroxyethyl methacrylate, hydroxypropyl methacrylate, isobornyl methacrylate, and caprolactone acrylate.

4. The 3D printing method of the thermally pre-cured two-component 3D printing photosensitive resin composition according to claim 1, characterized in that: The chain extender is a diol, diamine, or alkanolamine with a molecular weight of less than 800.

5. The 3D printing method of the thermally pre-cured two-component 3D printing photosensitive resin composition according to claim 1, characterized in that: The photoinitiator is one or more of 1-hydroxycyclohexylphenyl ketone, 2,4,6-trimethylbenzoyl-phosphorus dioxide, and 2-ethyloctyl-4-dimethylaminobenzoate.

6. The 3D printing method of the thermally pre-cured two-component 3D printing photosensitive resin composition according to claim 1, characterized in that: Step (4) further includes cleaning the solid-state printed part in ethanol, isopropanol or 70% ethanol aqueous solution.

7. The 3D printing method of the thermally pre-cured two-component 3D printing photosensitive resin composition according to claim 1, characterized in that: The heat transfer medium is selected from one or any mixture of methyl silicone oil, ethyl silicone oil, phenyl silicone oil, methyl hydrogen silicone oil, ethyl hydrogen silicone oil, methyl ethoxy silicone oil, and methyl trifluoropropyl silicone oil.

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