Polymerizable liquid for 3D printing, method for preparing three-dimensional object and application

Abstract

The invention provides a polymerizable liquid for 3D printing, a method for preparing a three-dimensional object and application, the polymerizable liquid comprises a closed or reactive closed polyurethane prepolymer, a closed or reactive closed curing agent, a stabilizer and a photoinitiator, the curing agent comprises an active group and a closed group, the active group and the closed group are in one-to-one correspondence, and the photoinitiator is in one-to-one correspondence with the active group and the closed group. The curing agent comprises an active group and a blocking group, the blocking group is used for blocking the active group, the active group can react with an unblocked polyurethane prepolymer, the stabilizer comprises a photocurable group and a stabilizing group, and the stabilizing group can react with the active group which is not completely blocked in the curing agent. Therefore, by adding the stabilizer, all active groups in the curing agent can be sealed, the storage stability of the polymerizable liquid is improved, the storage time of the polymerizable liquid is prolonged, and the waste of materials is effectively avoided. Moreover, the addition of the stabilizer does not affect the final printing performance of the polymerizable liquid.

Description

Technical Field

[0001] The present invention belongs to the field of polymer technology, and in particular relates to a polymerizable liquid for 3D printing and a method for preparing a three-dimensional object. Background Art

[0002] Photocuring 3D printing technology has gained increasing recognition because of its ability to print complex three-dimensional structures efficiently and with high precision.

[0003] 3D printed objects are formed by curing polymerizable liquids, and the curing reaction needs to occur under specific conditions. The polymerizable liquid includes multiple components. In order to avoid premature curing reactions between components when different components are mixed and stored, the active groups of the curing agent need to be capped to control the occurrence time of the curing reaction, so that the curing agent only undergoes curing reactions under specific conditions, ensuring that the curing agent can be stably stored under normal storage conditions and will not undergo curing reactions with other components.

[0004] However, the capping effect of the curing agent in the existing polymerizable liquid is poor, and a part of the active groups in the curing agent are not protected by the capping groups, that is, the existing polymerizable liquid cannot ensure that all the active groups of the curing agent are protected, which will reduce the storage stability of the curing agent, and further reduce the storage stability of the polymerizable liquid used for 3D printing, resulting in waste of materials.

[0005] Therefore, there is a need for improvements in polymerizable liquids. Summary of the invention

[0006] The present invention aims to improve the above technical problems at least to some extent.

[0007] To improve the above technical problems, the present invention provides a polymerizable liquid for 3D printing, the polymerizable liquid comprising: a closed or reactive closed polyurethane prepolymer, a closed or reactive closed curing agent, a stabilizer, and a photoinitiator, wherein the curing agent comprises an active group and a blocking group, the blocking group is used to block the active group, the active group can react with the unblocked polyurethane prepolymer, the stabilizer comprises a photocurable group and a stabilizing group, and the stabilizing group can react with the active group that is not completely blocked in the curing agent. Thus, by adding a stabilizer, it can be ensured that all active groups in the curing agent are blocked, the storage stability of the polymerizable liquid is improved, the storage (shelf) time of the polymerizable liquid is extended, and the waste of materials is effectively avoided. Moreover, the addition of the stabilizer will not affect the curing reaction, and will not affect the final printing performance of the polymerizable liquid.

[0008] According to an embodiment of the present invention, the photocurable group includes at least one of a methacrylate group and an acrylate group; the stabilizing group includes at least one of a carboxylic acid, an anhydride, an acyl chloride, a haloalkyl group, and an epoxy group.

[0009] According to an embodiment of the present invention, the stabilizer includes glycidyl methacrylate.

[0010] According to an embodiment of the present invention, the molar ratio of the stabilizing group to the active group is (0.02-0.1):1.

[0011] According to an embodiment of the present invention, the structural formula of the blocked or reactive blocked polyurethane prepolymer is as shown in formula (I):

[0012]

[0013] Wherein, A and R are independently selected from hydrocarbon groups, R' is NH or O, and Z comprises an epoxy group, an alkenyl group, an alkynyl group or a thiol terminal group.

[0014] According to an embodiment of the present invention, the structural formula of the blocked or reactive blocked curing agent is as shown in formula (II), formula (III), formula (IV), formula (V), formula (VI) or formula (VII):

[0015]

[0016] wherein R1, R2, and R3 are independently selected from unsubstituted, C1-C ... 36 Alkyl or alkylene, alkenyl or alkenylene, aryl or arylene, heteroaryl or heteroarylene, cycloalkyl or cycloalkenyl, cycloalkyl-alkyl-cycloalkyl;

[0017] R4, R5, R6 are independently selected from dialkyl-amino, C3-C 36 aryl or arylene, cycloalkyl or cycloalkenyl;

[0018] Y1 and Y2 are independently selected from protecting groups for protecting amino or hydroxyl groups;

[0019] X includes one of said photocurable groups.

[0020] According to an embodiment of the present invention, Y1 and Y2 are the following groups:

[0021]

[0022] According to an embodiment of the present invention, the polymerizable liquid further includes a reactive diluent.

[0023] The present invention also provides a method for preparing a three-dimensional object, the method comprising: placing the polymerizable liquid described above in a printing area; applying energy in the printing area, causing a polymerization reaction between the various components in the polymerizable liquid, and solidifying to form a three-dimensional object.

[0024] The present invention also provides the use of the aforementioned polymerizable liquid in 3D printing. DETAILED DESCRIPTION

[0025] The embodiments of the present application are described in detail below. The embodiments described below are exemplary and are only used to explain the present application, and should not be construed as limiting the present application. If no specific technology or conditions are indicated in the embodiments, the technology or conditions described in the documents in this area or the product instructions are used. The reagents used are not indicated by the manufacturer, and are all conventional products that can be purchased from the market.

[0026] The present invention provides a polymerizable liquid for 3D printing, the polymerizable liquid includes: a closed or reactive closed polyurethane prepolymer, a closed or reactive closed curing agent, a stabilizer, and a photoinitiator, wherein the curing agent includes an active group and a blocking group, the blocking group is used to block the active group, the active group can react with the unblocked polyurethane prepolymer, the stabilizer includes a photocurable group and a stabilizing group, and the stabilizing group can react with the active group that is not completely blocked in the curing agent. Thus, by adding a stabilizer, it can be ensured that all active groups in the curing agent are blocked, the storage stability of the polymerizable liquid is improved, the storage (shelf) time of the polymerizable liquid is extended, and the waste of materials is effectively avoided. Moreover, the addition of the stabilizer will not affect the curing reaction, and will not affect the final printing performance of the polymerizable liquid. In general, the polymerizable liquid of the present invention can be stably stored under normal storage conditions, and will not undergo a curing reaction with other components, which improves the problem of poor storage stability of the existing polymerizable liquid.

[0027] It should be noted that "blocked or reactive blocked" means that the active center of the compound is protected by a protecting group (or blocking group). Therefore, when different components are mixed, the components will not react prematurely, and the components will only react when the protecting group (or blocking group) is removed.

[0028] According to some embodiments of the present invention, the curing process of the polymerizable liquid for 3D printing includes a first curing process and a second curing process, wherein the first curing process is a photocuring stage, and under specific lighting conditions, some components in the polymerizable liquid can undergo a curing reaction under these conditions to generate an intermediate. Subsequently, under specific conditions of the second curing, the intermediate undergoes a second curing process to generate a three-dimensional object. Furthermore, the second curing process is a thermal curing stage, which can be performed under heating conditions. Among them, a closed or reactive closed polyurethane prepolymer participates in the second curing process, in which the polyurethane prepolymer is unblocked, and the unblocked polyurethane prepolymer reacts with other molecules.

[0029] According to an embodiment of the present invention, the active group of the curing agent includes an amine group, a hydroxyl group or a thiol group.

[0030] According to an embodiment of the present invention, the photocurable group includes at least one of a methacrylate group and an acrylate group; the stabilizing group includes at least one of a carboxylic acid, an acid anhydride, an acyl chloride, a haloalkyl group, and an epoxy group. Thus, the stabilizer can consume the active groups that are not protected by the blocking group to the greatest extent, while not affecting the photocuring reaction and the subsequent second curing reaction. The stabilizer of the present application has a photocurable group, so the stabilizer itself can participate in the photocuring reaction.

[0031] According to an embodiment of the present invention, the stabilizer includes glycidyl methacrylate.

[0032] According to an embodiment of the present invention, the molar ratio of the stabilizing group to the active group is (0.02-0.1):1. Thus, it can be ensured that the active groups in the curing agent that are not protected by the blocking groups are blocked by the stabilizing groups. If the molar ratio of the stabilizing group to the active group is too small, some of the active groups in the curing agent may not be blocked, resulting in the inability to significantly improve the storage stability of the polymerizable liquid. If the molar ratio of the stabilizing group to the active group is too large, when the active groups in the curing agent need to be released, too many stabilizing groups will affect the curing reaction to a certain extent.

[0033] According to an embodiment of the present invention, the structural formula of the blocked or reactive blocked polyurethane prepolymer is as shown in formula (I):

[0034]

[0035] Wherein, A and R are independently selected from hydrocarbon groups, R' is NH or O, and Z comprises an epoxy group, an alkenyl group, an alkynyl group or a thiol terminal group.

[0036] According to an embodiment of the present invention, the structural formula of the blocked or reactive blocked curing agent is as shown in formula (II), formula (III), formula (IV), formula (V), formula (VI) or formula (VII):

[0037]

[0038]

[0039] wherein R1, R2, and R3 are independently selected from unsubstituted, C1-C ... 36 Alkyl or alkylene, alkenyl or alkenylene, aryl or arylene, heteroaryl or heteroarylene, cycloalkyl or cycloalkenyl, cycloalkyl-alkyl-cycloalkyl;

[0040] R4, R5, R6 are independently selected from dialkyl-amino, C3-C 36 aryl or arylene, cycloalkyl or cycloalkenyl;

[0041] Y1 and Y2 are independently selected from protecting groups for protecting amino or hydroxyl groups;

[0042] X includes one of said photocurable groups.

[0043] According to an embodiment of the present invention, Y1 and Y2 are the following groups:

[0044]

[0045] According to an embodiment of the present invention, the polymerizable liquid further includes a reactive diluent.

[0046] According to some embodiments of the present invention, the reactive diluent includes a photocurable group, and the reactive diluent can participate in the photocuring process to improve the mechanical properties of the intermediate.

[0047] According to some embodiments of the present invention, a photoinitiator is used to initiate a photocuring reaction.

[0048] The present invention also provides a method for preparing a three-dimensional object, characterized in that the method comprises: placing the polymerizable liquid described above in a printing area; applying energy in the printing area, causing a polymerization reaction between the various components in the polymerizable liquid, and solidifying to form a three-dimensional object.

[0049] The present invention also provides the use of polymerizable liquid in 3D printing, thereby improving the physical properties of the 3D printed three-dimensional object.

[0050] The present invention is described below with reference to specific embodiments. It should be noted that these embodiments are merely illustrative and do not limit the present invention in any way.

[0051] Example 1

[0052] Preparation of closed or reactive closed polyurethane prepolymer: Add dry polybutylene glycol (PTMG) and 1,6-hexamethylene diisocyanate (HDI) in proportion (molar ratio 1:2) to a reaction vessel, heat and mix for a period of time, then add a certain proportion of di-n-butyltin dilaurate (DBTDL), react at 50-70°C for 2-3h, test the NCO value, then add an inhibitor, stir for 10min, slowly add tert-butylaminoethyl methacrylate (tBAEMA) for end-capping, and the reaction time is 3h. After the reaction is completed, add the inhibitor p-hydroxyanisole (MEHQ), mix well and discharge to obtain the final product.

[0053] Preparation of a closed or reactive closed curing agent: 1,10-decanediamine and an excess of 3,3-dimethyl-4-oxopentyl methacrylate (molar ratio of the substance is 1:2) and a certain amount of n-hexane are placed in a reactor, and the temperature is raised and stirred in an oil bath for reaction. The temperature is raised to 60-90°C to maintain reflux reaction, and the reaction time is 4-8 hours. Subsequently, glycidyl methacrylate (GMA, the molar ratio of the stabilizing group to the active group is (0.02:1)) is added to the reaction solution and reacted under heating conditions for 1-2 hours. After the reaction is completed, the product water and excess 3,3-dimethyl-4-oxopentyl methacrylate are removed by vacuum distillation at 30-70°C for 2-3 hours to obtain a light yellow transparent liquid with a yield of about 85%. After amino titration, the data results show that the amount of free amino groups is 245mg KOH / g.

[0054]

[0055] Prepare a polymerizable liquid: mix phenylbis(2,4,6-trimethylbenzoyl)phosphine oxide (photoinitiator 819), a blocked or reactive blocked polyurethane prepolymer, a blocked or reactive blocked curing agent, and a diluent and place them in a printing area, apply energy to the printing area, and a polymerization reaction occurs between the various components in the polymerizable liquid, which is then cured to form a three-dimensional object.

[0056] Example 2

[0057] Preparation of closed or reactive closed polyurethane prepolymer: Add dry PTMG and HDI in proportion (molar ratio 1:2) to the reaction vessel, heat and mix for a period of time, then add a certain proportion of DBTDL, react at 50-70℃ for 2-3h, test the NCO value, then add the inhibitor, stir for 10min, slowly add tBAEMA for end-capping, and the reaction time is 3h. After the reaction is completed, add the inhibitor MEHQ, mix well and discharge to obtain the final product.

[0058] Preparation of a closed or reactive closed curing agent: 1,10-decanediamine and an excess of 3,3-dimethyl-4-oxopentyl methacrylate (molar ratio of the substance is 1:2) and a certain amount of n-hexane are placed in a reactor, and the temperature is raised and stirred in an oil bath for reaction. The temperature is raised to 60-90°C and the reflux reaction is maintained for 4-8 hours. GMA is then added to the reaction solution, and the molar ratio of the stabilizing group to the active group is (0.1:1), and the reaction is carried out under heating conditions for 1-2 hours. After the reaction is completed, the product water and excess 3,3-dimethyl-4-oxopentyl methacrylate are removed by vacuum distillation at 30-70°C for 2-3 hours to obtain a light yellow transparent liquid with a yield of about 85%. After amino titration, the data results show that the amount of free amino groups is 233mg KOH / g.

[0059] Prepare polymerizable liquid: Mix photoinitiator 819, blocked or reactive blocked polyurethane prepolymer, blocked or reactive blocked curing agent and diluent and place them in the printing area, apply energy in the printing area, and polymerization reaction occurs between the various components in the polymerizable liquid, which is then cured to form a three-dimensional object.

[0060] Example 3

[0061] Preparation of closed or reactive closed polyurethane prepolymer: Add dry PTMG and HDI in proportion (molar ratio 1:2) to a reaction vessel, heat and mix for a period of time, then add a certain proportion of DBTDL, react at 50-70℃ for 2-3h, test the NCO value, then add the inhibitor, stir for 10min, slowly add tBAEMA for end-capping, and the reaction time is 3h. After the reaction is completed, add MEHQ, mix well and discharge to obtain the final product.

[0062] Preparation of a closed or reactive closed curing agent: 1,10-decanediamine and an excess of 3,3-dimethyl-4-oxopentyl methacrylate (molar ratio of the substance is 1:2) and a certain amount of n-hexane are placed in a reactor, and the temperature is raised and stirred in an oil bath for reaction. The temperature is raised to 60-90°C and the reflux reaction is maintained for 4-8 hours. Subsequently, GMA is added to the reaction solution, and the molar ratio of the stable group to the active group is (0.2:1), and the reaction is carried out under heating conditions for 1-2 hours. After the reaction is completed, the product water and excess 3,3-dimethyl-4-oxopentyl methacrylate are removed by vacuum distillation at 30-70°C for 2-3 hours to obtain a light yellow transparent liquid with a yield of about 85%. After amino titration, the data results show that the amount of free amino groups is 224mg KOH / g.

[0063] Prepare a polymerizable liquid: use phenylbis(2,4,6-trimethylbenzoyl)phosphine oxide (photoinitiator 819) as a photoinitiator, mix a closed or reactive closed polyurethane prepolymer, a closed or reactive closed curing agent, a photoinitiator and a diluent, place the prepared polymerizable liquid in a printing area, apply energy to the printing area, and a polymerization reaction occurs between the various components in the polymerizable liquid, which is then cured to form a three-dimensional object.

[0064] Comparative Example 1

[0065] Preparation of closed or reactive closed polyurethane prepolymer: Add dry PTMG and HDI in proportion (molar ratio 1:2) to the reaction vessel, heat and mix for a period of time, then add a certain proportion of DBTDL, react at 50-70℃ for 2-3h, test the NCO value, then add the inhibitor, stir for 10min, slowly add tBAEMA for end-capping, and the reaction time is 3h. After the reaction is completed, add the inhibitor MEHQ, mix well and discharge to obtain the final product.

[0066] Preparation of closed or reactive closed curing agent: 1,10-decanediamine and excess 3,3-dimethyl-4-oxopentyl methacrylate (molar ratio of substance 1:2) and a certain amount of n-hexane are placed in a reactor, and the temperature is raised and stirred in an oil bath for reaction. The temperature is raised to 60-90°C to maintain reflux reaction, and the reaction time is 4-8 hours. After the reaction is completed, 30-70°C is reduced pressure distilled for 2-3h to purify, remove product water and excess 3,3-dimethyl-4-oxopentyl methacrylate, and obtain a light yellow transparent liquid with a yield of about 85%. After amino titration, the data results show that the amount of free amino groups is 312mg KOH / g.

[0067] Prepare polymerizable liquid: Mix photoinitiator 819, blocked or reactive blocked polyurethane prepolymer, blocked or reactive blocked curing agent and diluent and place them in the printing area, apply energy in the printing area, and polymerization reaction occurs between the various components in the polymerizable liquid, which is then cured to form a three-dimensional object.

[0068] Performance test method: The tensile test strips formed by solidification were subjected to tensile test at a test rate of 500 mm / min. The instrument used was a universal electronic tensile tester and the test temperature was 23±2°C. The tensile modulus was defined as the slope of the stress-strain curve within the range of 3-10%, and the tensile strength was defined as the breaking stress.

[0069] The test results of Examples 1 to 3 and Comparative Example 1 are shown in Table 1.

[0070]

[0071] It can be seen from the comparison between Examples 1-3 and Comparative Example 1 that the physical properties of the three-dimensional objects printed out of the polymerizable liquid with the addition of stabilizer are better than the physical properties of the three-dimensional objects printed out of the polymerizable liquid without the addition of stabilizer. The improvement in the physical properties of the three-dimensional objects in Examples 1-3 indicates that the polymerizable liquid has not undergone a curing reaction, indicating that the addition of a stabilizer in the present application improves the storage stability of the polymerizable liquid.

[0072] In the description of this specification, the description with reference to the terms "one embodiment", "some embodiments", "example", "specific example", or "some examples" etc. means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described may be combined in any one or more embodiments or examples in a suitable manner. In addition, those skilled in the art may combine and combine the different embodiments or examples described in this specification and the features of the different embodiments or examples, without contradiction.

[0073] Although the embodiments of the present invention have been shown and described above, it is to be understood that the above embodiments are exemplary and are not to be construed as limitations of the present invention. A person skilled in the art may change, modify, replace and vary the above embodiments within the scope of the present invention.

Claims

1. A polymerizable liquid for 3D printing, characterized in that: The polymerizable liquid includes: a blocked or reactive blocked polyurethane prepolymer, a blocked or reactive blocked curing agent, a stabilizer, and a photoinitiator, wherein the curing agent includes an active group and a blocking group, the blocking group is used to block the active group, and the active group can react with the unblocked polyurethane prepolymer, and the stabilizer includes a photocurable group and a stabilizing group, and the stabilizing group can react with the active group in the curing agent that has not been completely blocked.

2. The polymerizable liquid according to claim 1, characterized in that The photocurable group includes at least one of a methacrylate group and an acrylate group; The stabilizing group includes at least one of carboxylic acid, acid anhydride, acid chloride, halogenated alkyl, and epoxy.

3. The polymerizable liquid according to claim 2, characterized in that The stabilizer includes glycidyl methacrylate.

4. The polymerizable liquid according to claim 1, characterized in that The molar ratio of the stabilizing group to the active group is (0.02-0.1):

1.

5. The polymerizable liquid according to claim 1, characterized in that The structural formula of the blocked or reactive blocked polyurethane prepolymer is shown in formula (I): Wherein, A and R are independently selected from hydrocarbon groups, R' is NH or O, and Z comprises an epoxy group, an alkenyl group, an alkynyl group or a thiol terminal group.

6. The polymerizable liquid according to claim 1, characterized in that The structural formula of the blocked or reactive blocked curing agent is shown in formula (II), formula (III), formula (IV), formula (V), formula (VI) or formula (VII): wherein R1, R2, and R3 are independently selected from unsubstituted, C1-C ... 36 Alkyl or alkylene, alkenyl or alkenylene, aryl or arylene, heteroaryl or heteroarylene, cycloalkyl or cycloalkenyl, cycloalkyl-alkyl-cycloalkyl; R4, R5, R6 are independently selected from dialkyl-amino, C3-C 36 aryl or arylene, cycloalkyl or cycloalkenyl; Y1 and Y2 are independently selected from protecting groups for protecting amino or hydroxyl groups; X includes one of said photocurable groups.

7. The polymerizable liquid according to claim 6, characterized in that The Y1 and Y2 are the following groups:

8. The polymerizable liquid according to claim 7, characterized in that The polymerizable liquid also includes a reactive diluent.

9. A method for preparing a three-dimensional object, characterized in that: The method comprises: Placing the polymerizable liquid according to any one of claims 1 to 8 in a printing area; Energy is applied to the printing area, and a polymerization reaction occurs between the various components in the polymerizable liquid, which is solidified to form a three-dimensional object.

10. Use of the polymerizable liquid according to any one of claims 1 to 8 in 3D printing.

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