Dual-curable polyoxazolidinone prepolymer and resin composition for 3D printing

Abstract

The invention provides a dual-curable polyoxazolidinone prepolymer and a resin composition for 3D printing, and particularly relates to the technical field of 3D printing materials. The dual-curable polyoxazolidinone prepolymer is prepared by the following steps: carrying out first reaction on dihydric alcohol and diisocyanate to generate an isocyanate-terminated polyurethane prepolymer; carrying out second reaction on the polyoxazolidinone and epoxy resin to generate polyoxazolidinone with isocyanate at two ends; and finally, carrying out third reaction on the polyoxazolidinone and a sealing agent to obtain the dual-cured polyoxazolidinone prepolymer. And the sealing agent is an aminomethacrylate compound. The polyoxazolidinone prepolymer provided by the invention provides excellent toughness through a polyurethane part synthesized by dihydric alcohol, and photo-thermal dual curing is realized through metacrylic acid ester end capping. The dual-curing mode not only improves the crosslinking density and uniformity, but also significantly enhances the mechanical properties, including strength, toughness and durability, of the material, so that the material can be efficiently cured under illumination or heating conditions to form a uniform three-dimensional network structure.

Description

Technical Field

[0001] The invention relates to the technical field of 3D printing materials, and in particular to a dual-curable polyoxazolidone prepolymer and a resin composition for 3D printing. Background Art

[0002] 3D printing resin, as the core material of light-curing 3D printing technology, plays an important role in medical, jewelry design, dentistry and other fields with extremely high precision requirements due to its high precision, smooth surface and rapid prototyping. These resin materials can not only achieve fine printing details and complex geometric structures, but also provide a variety of physical properties such as high strength, elasticity, transparency, high temperature resistance, etc. to meet different application requirements.

[0003] However, 3D printing resins also have some technical defects. For example, some resin materials are prone to breakage when impacted or twisted, which limits their application in long-term load-bearing or harsh environments. In addition, the weather resistance of resin materials is relatively poor, and long-term exposure to ultraviolet light may gradually degrade, affecting their physical properties and appearance color. Although there are a variety of resin formulations on the market, compared with other 3D printing technologies, the material types of photosensitive resins are still limited, and some functional resins such as high-temperature resins and elastic resins are more expensive. In order to improve the mechanical properties of 3D printing resins and meet specific application requirements, material scientists are constantly developing new resin formulations to improve the toughness, hardness, high temperature resistance and other properties of the resin.

[0004] In view of this, the present invention is proposed. Summary of the invention

[0005] One of the purposes of the present invention is to provide a dual-curable polyoxazolidone prepolymer, aiming to solve at least one of the above-mentioned technical problems in the prior art.

[0006] A second object of the present invention is to provide a resin composition for 3D printing.

[0007] A third object of the present invention is to provide a method for using the resin composition for 3D printing.

[0008] In order to solve the above technical problems, the present invention particularly adopts the following technical solutions:

[0009] The first aspect of the present invention provides a dual-curable polyoxazolidone prepolymer, which is prepared by a first reaction between a diol and a diisocyanate to form an isocyanate-terminated polyurethane prepolymer; the isocyanate-terminated polyurethane prepolymer is then reacted with an epoxy resin to form a polyoxazolidone having isocyanate at both ends; and finally the polyoxazolidone having isocyanate at both ends is reacted with a blocking agent to form a dual-curable polyoxazolidone prepolymer.

[0010] Wherein, the blocking agent is an aminomethyl acrylate compound.

[0011] Furthermore, the aminomethylacrylate compound includes at least one of tert-butylaminoethyl methacrylate, tert-amylaminoethyl methacrylate, tert-hexylaminoethyl methacrylate and tert-butylaminopropyl methacrylate.

[0012] Preferably, the diol comprises a polyether diol and / or a polyester diol.

[0013] Preferably, the polyether diol includes at least one of polyethylene glycol, polypropylene glycol and polytetramethylene glycol.

[0014] Preferably, the polyester diol comprises polycaprolactone diol.

[0015] Further, the diisocyanate includes at least one of hexamethylene diisocyanate, isophorone diisocyanate, 4,4'-dicyclohexylmethane diisocyanate and toluene diisocyanate.

[0016] Preferably, the epoxy resin includes at least one of bisphenol A diglycidyl ether, bisphenol F diglycidyl ether, 1,4-cyclohexanedicarboxylic acid diglycidyl ester, terephthalic acid diglycidyl ester and polypropylene glycol diglycidyl ether.

[0017] Furthermore, the temperature of the first reaction is 70-90° C., and the time is 2-5 hours.

[0018] Preferably, the catalyst used in the first reaction includes dibutyltin dilaurate.

[0019] Preferably, the temperature of the second reaction is 150-170° C., and the time is 2-5 hours.

[0020] Preferably, the catalyst used in the second reaction comprises lithium chloride.

[0021] Preferably, the temperature of the third reaction is 70-90° C., and the time is 0.5-2 h.

[0022] Preferably, a polymerization inhibitor is added in the third reaction.

[0023] Preferably, the polymerization inhibitor comprises p-hydroxyanisole.

[0024] Preferably, the molar ratio of diol, diisocyanate, epoxy resin and blocking agent is 0.5-0.8:1.6:0.25-0.5:0.5-1.2.

[0025] The second aspect of the present invention provides a resin composition for 3D printing, which comprises, by mass percentage, 30-60% of a dual-curable polyoxazolidone prepolymer, 25-50% of a photocurable diluent monomer, 10-20% of a curing agent, and 0.5-2% of a photoinitiator;

[0026] Wherein, the dual-curable polyoxazolidone prepolymer is the dual-curable polyoxazolidone prepolymer described in the first aspect.

[0027] Further, the photocurable diluent monomer has at least one functionality.

[0028] Preferably, the photocurable diluent monomer comprises isobornyl acrylate, isobornyl methacrylate, 1,3-propylene glycol diacrylate, 1,3-propylene glycol dimethacrylate, 1,4-butylene glycol diacrylate, 1,4-butylene glycol dimethacrylate, 1,5-pentanediol diacrylate, 1,5-pentanediol dimethacrylate, 1,6-hexanediol diacrylate, 1,6-hexanediol dimethacrylate, 1,7-heptanediol diacrylate, 1,7-heptanediol dimethacrylate, 1,8-octanediol diacrylate, 1,8-octanediol diacrylate. At least one of dimethacrylate, trimethylolpropane triol triacrylate, trimethylolpropane triol trimethacrylate, ethoxylated trimethylolpropane triol triacrylate, ethoxylated trimethylolpropane triol trimethacrylate, neopentyl glycol diacrylate, neopentyl glycol dimethacrylate, tripropylene glycol diacrylate, tripropylene glycol dimethacrylate, pentaerythritol triacrylate, pentaerythritol trimethacrylate, tricyclohexane dimethanol diacrylate, tricyclohexane dimethanol dimethacrylate and dimethylacrylamide.

[0029] Preferably, the curing agent includes at least one of an aromatic amine, an alicyclic amine and an aliphatic amine.

[0030] Preferably, the aromatic amine comprises 4,4-methylenebis(2,6-diethylaniline).

[0031] Preferably, the alicyclic amine includes 3,3-dimethyl-4,4-diaminodicyclohexylmethane.

[0032] Preferably, the aliphatic amine comprises a polyetheramine.

[0033] Preferably, the grades of the polyetheramine include D230 and / or T403.

[0034] Preferably, the photoinitiator comprises at least one of benzoin ether, dialkyl acetophenone, acylphosphine oxide and benzoylphosphine oxide.

[0035] Furthermore, the resin composition for 3D printing also includes a color paste with a mass percentage of 0.1 to 0.5%.

[0036] The third aspect of the present invention provides a method for using the resin composition, which is to load the resin composition into a 3D light-curing printer, perform light-curing printing to obtain a preliminary molding material; then thermally cure the preliminary molding material to obtain a 3D printed model.

[0037] Furthermore, in the light-curing printing, the wavelength of the light source is 360-400 nm, the temperature is 20-35° C., the humidity is 34-45%, and the film thickness is 50-100 μm.

[0038] Preferably, the thermal curing process is: firstly keep the temperature at 80-100°C for 2-4 hours, and then increase the temperature to 140-160°C and keep the temperature for 4-6 hours.

[0039] Compared with the prior art, the present invention has at least the following beneficial effects:

[0040] The polyoxazolidone prepolymer of dual curing provided by the present invention contains a polyurethane part synthesized by a diol, and provides good toughness for the prepolymer; the prepolymer is capped by a pyrolyzable methacrylate at the same time, and this capping mode not only gives the prepolymer the ability of light curing, but also enables it to further enhance its performance by thermal curing. Therefore, the polyoxazolidone prepolymer has the characteristics of dual curing, and can not only initiate a curing reaction by illumination, but also complete the curing process under heated conditions. The ability of this dual curing enables the polyoxazolidone prepolymer to form a three-dimensional network structure with higher crosslinking density and uniformity after curing. The realization of this structure significantly improves the mechanical properties of the prepolymer, including its strength, toughness and durability.

[0041] In the resin composition for 3D printing provided by the present invention, the polyoxazolidone prepolymer gives the resin composition excellent toughness and strength, ensuring the durability and stability of the printed part during use. The photocurable diluent monomer optimizes the fluidity and printing accuracy of the resin composition, making the printing of complex structures smoother and reducing blockages and defects during the printing process; the curing agent improves the cross-linking density of the printed part and enhances the mechanical properties and thermal stability of the resin composition. The photoinitiator enables the resin composition to cure rapidly under light, shortens the printing time, and improves production efficiency. The resin composition not only improves the physical properties of the printed part through a dual curing mechanism, but also optimizes the printing process, and has broad application prospects, especially in the field of 3D printing that requires high strength and high precision.

[0042] The method of use provided by the present invention is to load a resin composition into a 3D light-curing printer and use light-curing technology to accurately construct a preliminary molding material layer by layer. This step can not only achieve rapid prototyping of complex designs, but also ensure the fineness and surface quality of the printed parts. Subsequently, through thermal curing treatment, the cross-linking density and mechanical properties of the preliminary molding material are further enhanced, thereby obtaining a 3D printed model with stable structure and strong durability. This dual curing process combining light curing and thermal curing effectively improves the accuracy and performance of the printed parts, making it widely applicable in a variety of engineering and industrial applications. BRIEF DESCRIPTION OF THE DRAWINGS

[0043] In order to more clearly illustrate the specific implementation methods of the present invention or the technical solutions in the prior art, the drawings required for use in the specific implementation methods or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are some implementation methods of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0044] Figure 1 It is a reaction diagram of dual curing;

[0045] Figure 2 This is the wear model obtained from Examples 8 to 11 and Comparative Examples 1 to 2. DETAILED DESCRIPTION

[0046] In order to make the purpose, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below in combination with the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. The components of the embodiments of the present invention described and shown herein can be arranged and designed in various different configurations.

[0047] The first aspect of the present invention provides a dual-curable polyoxazolidone prepolymer, which is prepared by a first reaction between a diol and a diisocyanate to form an isocyanate-terminated polyurethane prepolymer; the isocyanate-terminated polyurethane prepolymer is then reacted with an epoxy resin to form a polyoxazolidone having isocyanate at both ends; and finally the polyoxazolidone having isocyanate at both ends is reacted with a blocking agent to form a dual-curable polyoxazolidone prepolymer.

[0048] Wherein, the blocking agent is an aminomethyl acrylate compound.

[0049] The polyoxazolidone prepolymer of dual curing provided by the present invention contains a polyurethane part synthesized by a diol, and provides good toughness for the prepolymer; the prepolymer is capped by a pyrolyzable methacrylate at the same time, and this capping mode not only gives the prepolymer the ability of light curing, but also enables it to further enhance its performance by thermal curing. Therefore, the polyoxazolidone prepolymer has the characteristics of dual curing, and can not only initiate a curing reaction by illumination, but also complete the curing process under heated conditions. The ability of this dual curing enables the polyoxazolidone prepolymer to form a three-dimensional network structure with higher crosslinking density and uniformity after curing. The realization of this structure significantly improves the mechanical properties of the prepolymer, including its strength, toughness and durability.

[0050] Furthermore, the aminomethylacrylate compound includes at least one of tert-butylaminoethyl methacrylate, tert-amylaminoethyl methacrylate, tert-hexylaminoethyl methacrylate and tert-butylaminopropyl methacrylate.

[0051] Taking tert-butylaminoethyl methacrylate as an example, the reaction process of the obtained methacrylate-blocked polyoxazolidone prepolymer is as follows:

[0052]

[0053] Among them, R1 is the omitted group in the diol; R2 is the omitted group in the diisocyanate; R3 is the omitted group in the epoxy resin.

[0054] Preferably, the diol includes polyether diol and / or polyester diol, and the diol is dehydrated before use to reduce the water content therein and improve the purity of the prepolymer.

[0055] Preferably, the polyether diol includes at least one of polyethylene glycol, polypropylene glycol and polytetramethylene glycol.

[0056] Preferably, the polyester diol comprises polycaprolactone diol.

[0057] Further, the diisocyanate includes at least one of hexamethylene diisocyanate, isophorone diisocyanate, 4,4'-dicyclohexylmethane diisocyanate and toluene diisocyanate.

[0058] Preferably, the epoxy resin includes at least one of bisphenol A diglycidyl ether, bisphenol F diglycidyl ether, 1,4-cyclohexanedicarboxylic acid diglycidyl ester, terephthalic acid diglycidyl ester and polypropylene glycol diglycidyl ether.

[0059] Furthermore, the temperature of the first reaction is 70-90° C., and the time is 2-5 hours.

[0060] Typically but not limiting, the temperature of the first reaction can be 70°C, 75°C, 80°C, 85°C or 90°C, or any value within the range of 70°C to 90°C; the time of the first reaction can be 2 hours, 3 hours, 4 hours or 5 hours, or any value within the range of 2 hours to 5 hours.

[0061] Preferably, the catalyst used in the first reaction includes dibutyltin dilaurate.

[0062] Preferably, the temperature of the second reaction is 150-170° C., and the time is 2-5 hours.

[0063] Typically but not limiting, for the second reaction, the temperature can be 150°C, 155°C, 160°C, 165°C or 170°C, and can also be any temperature in the range of 150°C to 170°C; the time of the second reaction can be 2 hours, 3 hours, 4 hours or 5 hours, and can also be any time in the range of 2 hours to 5 hours.

[0064] Preferably, the catalyst used in the second reaction comprises lithium chloride.

[0065] Preferably, the temperature of the third reaction is 70-90° C., and the time is 0.5-2 h.

[0066] Typically but not limiting, the temperature of the third reaction can be 70°C, 75°C, 80°C, 85°C or 90°C, and can be any value in the range of 70°C to 90°C; the time of the third reaction can be 30 minutes, 1 hour, 1.5 hours, or any time in the range of 0.5 hour to 2 hours.

[0067] Preferably, a polymerization inhibitor is added in the third reaction.

[0068] Preferably, the polymerization inhibitor comprises p-hydroxyanisole.

[0069] Preferably, the molar ratio of diol, diisocyanate, epoxy resin and blocking agent is 0.5-0.8:1.6:0.25-0.5:0.5-1.2.

[0070] Typically but not limiting, the molar ratio of diol, diisocyanate, epoxy resin and blocking agent can be, for example, 0.5:1.6:0.25:1, 0.6:1.6:0.3:1, 0.7:1.6:0.35:1, 0.8:1.6:0.4:1, 0.5:1.6:0.25:1.2, 0.6:1.6:0.3:1.2, 0.7:1.6:0.35:1.2, 0.8:1.6:0.4:1.2, or any value within the range of 0.5-0.8:1.6:0.25-0.5:0.5-1.2.

[0071] The second aspect of the present invention provides a resin composition for 3D printing, which comprises, by mass percentage, 30-60% of a dual-curable polyoxazolidone prepolymer, 25-50% of a photocurable diluent monomer, 10-20% of a curing agent, and 0.5-2% of a photoinitiator;

[0072] Wherein, the dual-curable polyoxazolidone prepolymer is the dual-curable polyoxazolidone prepolymer described in the first aspect.

[0073] In the resin composition for 3D printing provided by the present invention, the polyoxazolidone prepolymer gives the resin composition excellent toughness and strength, ensuring the durability and stability of the printed part during use. The photocurable diluent monomer optimizes the fluidity and printing accuracy of the resin composition, making the printing of complex structures smoother and reducing blockages and defects during the printing process; the curing agent improves the cross-linking density of the printed part and enhances the mechanical properties and thermal stability of the resin composition. The photoinitiator enables the resin composition to cure rapidly under light, shortens the printing time, and improves production efficiency. The resin composition not only improves the physical properties of the printed part through a dual curing mechanism, but also optimizes the printing process, and has broad application prospects, especially in the field of 3D printing that requires high strength and high precision.

[0074] Typically but not limiting, the mass percentage of the polyoxazolidone prepolymer can be 30%, 35%, 40%, 45%, 50%, 55% or 60%, or any value within the range of 30% to 60%; the proportion of the photocurable diluent monomer can be 25%, 30%, 35%, 40%, 45%, 48% or 50%, or any value within the range of 25% to 50%, which helps to adjust the viscosity and processing properties of the resin. The proportion of the curing agent can be 10%, 12%, 14%, 16%, 18% or 20%, or any value within the range of 10% to 20%, to ensure that the resin has appropriate reactivity and curing speed during the photocuring process. The proportion of the photoinitiator can be 0.5%, 1%, 1.5% or 2%, or any value within the range of 0.5% to 2%, which is responsible for initiating the rapid polymerization reaction of the resin under light.

[0075] Furthermore, the photocurable diluent monomer has at least one functionality. Here, functionality refers to the type of active functional groups in the photocurable diluent monomer. A photocurable diluent monomer having at least one functionality means that the monomer molecule contains at least one functional group that can participate in the photocuring reaction. Monofunctional monomers mainly play a diluting role in the photocuring process to generate linear polymers, which helps to improve the flexibility of the material. Multifunctional monomers (such as trimethylolpropane triol triacrylate) not only act as a diluent, but also as a crosslinking agent, which can significantly increase the curing speed and crosslinking density, thereby enhancing the hardness, scratch resistance and other properties of the cured film.

[0076] Preferably, the photocurable diluent monomer comprises isobornyl acrylate, isobornyl methacrylate, 1,3-propylene glycol diacrylate, 1,3-propylene glycol dimethacrylate, 1,4-butylene glycol diacrylate, 1,4-butylene glycol dimethacrylate, 1,5-pentanediol diacrylate, 1,5-pentanediol dimethacrylate, 1,6-hexanediol diacrylate, 1,6-hexanediol dimethacrylate, 1,7-heptanediol diacrylate, 1,7-heptanediol dimethacrylate, 1,8-octanediol diacrylate, 1,8-octanediol diacrylate. At least one of dimethacrylate, trimethylolpropane triol triacrylate, trimethylolpropane triol trimethacrylate, ethoxylated trimethylolpropane triol triacrylate, ethoxylated trimethylolpropane triol trimethacrylate, neopentyl glycol diacrylate, neopentyl glycol dimethacrylate, tripropylene glycol diacrylate, tripropylene glycol dimethacrylate, pentaerythritol triacrylate, pentaerythritol trimethacrylate, tricyclohexane dimethanol diacrylate, tricyclohexane dimethanol dimethacrylate and dimethylacrylamide.

[0077] Preferably, the curing agent includes at least one of an aromatic amine, an alicyclic amine and an aliphatic amine.

[0078] Preferably, the aromatic amine comprises 4,4-methylenebis(2,6-diethylaniline).

[0079] Preferably, the alicyclic amine includes 3,3-dimethyl-4,4-diaminodicyclohexylmethane.

[0080] Preferably, the aliphatic amine comprises a polyetheramine.

[0081] Preferably, the grades of the polyetheramine include D230 and / or T403.

[0082] Preferably, the photoinitiator comprises at least one of benzoin ether, dialkyl acetophenone, acylphosphine oxide and benzoylphosphine oxide.

[0083] Furthermore, the resin composition for 3D printing also includes a color paste with a mass percentage of 0.1 to 0.5%.

[0084] Typically but not limiting, the color paste ratio may be 0.1%, 0.2%, 0.3%, 0.4% or 0.5%, or any value within the range of 0.1-0.5%.

[0085] The third aspect of the present invention provides a method for using the resin composition, which is to load the resin composition into a 3D light-curing printer, perform light-curing printing to obtain a preliminary molding material; then thermally cure the preliminary molding material to obtain a 3D printed model.

[0086] The method of use provided by the present invention is to load a resin composition into a 3D light-curing printer and use light-curing technology to accurately construct a preliminary molding material layer by layer. This step can not only achieve rapid prototyping of complex designs, but also ensure the fineness and surface quality of the printed parts. Subsequently, through thermal curing treatment, the cross-linking density and mechanical properties of the preliminary molding material are further enhanced, thereby obtaining a 3D printed model with stable structure and strong durability. This dual curing process combining light curing and thermal curing effectively improves the accuracy and performance of the printed parts, making it widely applicable in a variety of engineering and industrial applications.

[0087] Taking methacrylate-blocked polyoxazolidinone prepolymer as an example, the reactions that occur during the process are as follows: Figure 1 As shown, the dual curing process of light curing and thermal curing improves the mechanical properties of the material.

[0088] Furthermore, in the light-curing printing, the wavelength of the light source is 360-400 nm, the temperature is 20-35° C., the humidity is 34-45%, and the film thickness is 50-100 μm.

[0089] Typically but not limiting, the wavelength of the light source used in the photocuring printing process can be 360nm, 365nm, 370nm, 375nm, 380nm, 385nm, 390nm, 395nm, 400nm, or any value in the range of 360nm to 400nm, to ensure that the photoinitiator can effectively absorb light energy and initiate polymerization. The temperature in the photocuring printing process can be 20°C, 22°C, 24°C, 26°C, 28°C, 30°C, 32°C, 34°C or 35°C, or any temperature in the range of 20°C to 35°C, to ensure the fluidity and reactivity of the resin during the curing process. The humidity can be 34%, 36%, 38%, 40%, 42%, 44% or 45%, or any humidity in the range of 34% to 45%, to control the reaction of water molecules in the resin during the curing process. The film thickness can be 50 μm, 60 μm, 70 μm, 80 μm, 90 μm or 100 μm, or any value within the range of 50 μm to 100 μm to ensure that the printed part has uniform curing depth and mechanical properties.

[0090] Preferably, the thermal curing process is: firstly keeping the temperature at 80-100° C. for 2-4 hours, and then heating to 140-160° C. for 4-6 hours.

[0091] Preferably, the thermal curing process can first be kept at 80°C, 85°C, 90°C, 95°C or 100°C for 2 hours, 3 hours or 4 hours, or any temperature within the range of 80°C to 100°C and any time within the range of 2 hours to 4 hours, to promote the initial curing of the resin. Subsequently, the temperature is raised to 140°C, 145°C, 150°C or 160°C and kept for 4 hours, 5 hours or 6 hours, or any temperature within the range of 140°C to 160°C and any time within the range of 4 hours to 6 hours, to complete the deep curing of the resin and improve the crosslinking density and thermal stability of the printed part.

[0092] In the following, some embodiments of the present invention are described in detail in conjunction with the embodiments. In the absence of conflict, the following embodiments and the features in the embodiments can be combined with each other. The raw materials used in the present invention can be obtained by commercial purchase unless otherwise specified.

[0093] Example 1

[0094] This embodiment provides a dual-curable polyoxazolidone prepolymer, the preparation method of which is as follows:

[0095] 1. First, add 100g PTMG-650 (BASF) into a four-necked flask equipped with a stirring paddle, a thermometer, a nitrogen introduction system, and a condenser reflux tube, dehydrate at 110°C for 1h, then cool to 60°C, add 0.05g catalyst dibutyltin dilaurate and 82g isophorone diisocyanate (Wanhua Chemical), and after the temperature stabilizes, keep the temperature at 80°C for 3h to obtain an isocyanate-terminated polyurethane prepolymer.

[0096] 2. Under nitrogen protection, the above-mentioned isocyanate-terminated polyurethane prepolymer, 25g of bisphenol A epoxy resin GY6010 (Huntsman) and 0.3g of LiCl were added to a reactor, heated to 160°C for reaction for 3h, then cooled to 80°C, 0.2g of p-hydroxyanisole inhibitor and 18.5g of tert-butylaminoethyl methacrylate (TBAEMA) were added respectively, and the reaction was continued for 1h to finally obtain a dual-curable polyoxazolidone prepolymer with a viscosity of 43000mPa.s (50°C).

[0097] Example 2

[0098] This embodiment provides a dual-curable polyoxazolidone prepolymer, the preparation method of which is as follows:

[0099] 1. First, add 100g PTMG-650 (BASF) into a four-necked flask equipped with a stirring paddle, a thermometer, a nitrogen introduction system, and a condenser reflux tube, dehydrate at 110°C for 1h, then cool to 60°C, add 0.05g catalyst dibutyltin dilaurate and 96g 4,4'-dicyclohexylmethane diisocyanate (Wanhua Chemical), and after the temperature stabilizes, keep the temperature at 80°C for 3h to obtain an isocyanate-terminated polyurethane prepolymer.

[0100] 2. Under nitrogen protection, the above-mentioned isocyanate-terminated polyurethane prepolymer, 38g of polypropylene glycol diglycidyl ether SM632 (Jiangsu Sanmu) and 0.5g of LiCl were added to a reactor, heated to 160°C for reaction for 3h, then cooled to 80°C and 0.2g of p-hydroxyanisole inhibitor and 18.5g of tert-butylaminoethyl methacrylate (TBAEMA) were added respectively, the reaction was continued for 1h, and finally a dual-curable polyoxazolidone prepolymer with a viscosity of 33000mpa.s (50°C) was obtained.

[0101] Example 3

[0102] This embodiment provides a dual-curable polyoxazolidone prepolymer, the preparation method of which is as follows:

[0103] 1. First, add 100g PCL-2053 (Hunan Juren Chemical) into a four-necked flask equipped with a stirring paddle, a thermometer, a nitrogen introduction system, and a condensing reflux tube, dehydrate at 110°C for 1h, then cool to 60°C, add 0.05g catalyst dibutyltin dilaurate and 92g isophorone diisocyanate (Wanhua Chemical), and after the temperature stabilizes, keep the temperature at 80°C for 3h to obtain an isocyanate-terminated polyurethane prepolymer.

[0104] 2. Under nitrogen protection, the above-mentioned isocyanate-terminated polyurethane prepolymer, 25g of bisphenol A epoxy resin GY6010 (Huntsman) and 0.3g of LiCl were added to a reactor, heated to 160°C for reaction for 3h, then cooled to 80°C, 0.2g of p-hydroxyanisole inhibitor and 18.5g of tert-butylaminoethyl methacrylate (TBAEMA) were added respectively, and the reaction was continued for 1h to finally obtain a dual-curable polyoxazolidone prepolymer with a viscosity of 45000mPa.s (50°C).

[0105] Example 4

[0106] This embodiment provides a dual-curable polyoxazolidone prepolymer, the preparation method of which is as follows:

[0107] 1. First, add 100g PCL-2053 (Hunan Juren Chemical) into a four-necked flask equipped with a stirring paddle, a thermometer, a nitrogen introduction system, and a condensing reflux tube, dehydrate at 110°C for 1h, then cool to 60°C, add 0.05g catalyst dibutyltin dilaurate and 92g isophorone diisocyanate (Wanhua Chemical), and after the temperature stabilizes, keep the temperature at 80°C for 3h to obtain an isocyanate-terminated polyurethane prepolymer.

[0108] 2. Under nitrogen protection, the above-mentioned isocyanate-terminated polyurethane prepolymer, 15g bisphenol A epoxy resin GY6010 (Huntsman), 14g polypropylene glycol diglycidyl ether SM632 (Jiangsu Sanmu) and 0.3g LiCl were added to a reactor, heated to 160°C for reaction for 3h, then cooled to 80°C, 0.2g p-hydroxyanisole inhibitor and 18.5g tert-butylaminoethyl methacrylate (TBAEMA) were added respectively, and the reaction was continued for 1h to finally obtain a dual-curable polyoxazolidone prepolymer with a viscosity of 36000mPa.s (50°C).

[0109] Example 5

[0110] This embodiment provides a dual-curable polyoxazolidone prepolymer, which is different from the embodiment 3 in that in step 2, tert-butylaminoethyl methacrylate (TBAEMA) is replaced with tert-amylaminoethyl methacrylate, and the remaining raw materials and methods are the same as those in the embodiment 3, which are not described here. The viscosity of the dual-curable polyoxazolidone prepolymer is 43000mpa.s (50°C).

[0111] Example 6

[0112] This embodiment provides a dual-curable polyoxazolidone prepolymer, which is different from the embodiment 3 in that in step 2, tert-butylaminoethyl methacrylate (TBAEMA) is replaced with tert-hexylaminoethyl methacrylate, and the remaining raw materials and methods are the same as those in the embodiment 3, which are not described here. The viscosity of the dual-curable polyoxazolidone prepolymer is 42000mpa.s (50°C).

[0113] Example 7

[0114] This embodiment provides a dual-curable polyoxazolidone prepolymer, which is different from the embodiment 3 in that in step 2, tert-butylaminopropyl methacrylate is used to replace tert-butylaminoethyl methacrylate (TBAEMA), and the remaining raw materials and methods are the same as those in the embodiment 3, which are not described here. The viscosity of the dual-curable polyoxazolidone prepolymer is 45000mpa.s (50°C).

[0115] Embodiments 8 to 14

[0116] These embodiments provide a resin composition for 3D printing, which includes 50 parts of the dual-curable polyoxazolidone prepolymer provided in Examples 1 to 7, 30 parts of tricyclohexane dimethanol dimethacrylate, 18 parts of 3,3-dimethyl-4,4-diaminodicyclohexylmethane, 1.8 parts of diphenyl-(2,4,6-trimethylbenzoyl)phosphine oxide, and 0.2 parts of black paste.

[0117] These resin compositions are obtained by uniformly mixing the above raw materials and stirring at 25° C. for 60 minutes to obtain a uniform liquid.

[0118] Comparative Example 1

[0119] This comparative example provides a resin composition for 3D printing, including 25 parts of bisphenol A epoxy resin GY6010, 30 parts of tricyclohexane dimethanol dimethacrylate, 25 parts of isobornyl methacrylate, 18 parts of 3,3-dimethyl-4,4-diaminodicyclohexylmethane, 1.8 parts of diphenyl-(2,4,6-trimethylbenzoyl)phosphine oxide and 0.2 parts of black paste.

[0120] The above raw materials were mixed uniformly, and stirred at 25° C. for 60 min to obtain a uniform liquid, thereby obtaining a resin composition.

[0121] Comparative Example 2

[0122] This comparative example provides a resin composition for 3D printing, including 25 parts of bisphenol A epoxy resin GY6010, 22 parts of tricyclohexane dimethanol dimethacrylate, 25 parts of isobornyl methacrylate, 18 parts of 3,3-dimethyl-4,4-diaminodicyclohexylmethane, 8 parts of ABS liquid toughener, 1.8 parts of diphenyl-(2,4,6-trimethylbenzoyl)phosphine and 0.2 parts of black paste.

[0123] The above raw materials were mixed uniformly, and stirred at 25° C. for 60 min to obtain a uniform liquid, thereby obtaining a resin composition.

[0124] Test Case

[0125] The resin compositions for 3D printing of Examples 8 to 14 and Comparative Examples 1 to 2 were 3D printed respectively, and each resin composition was printed 3 times to obtain tensile specimens, heat deformation temperature specimens and wear models respectively.

[0126] The wavelength of the light source was set to 385 nm, the 3D printing temperature was set to 30 °C, the humidity was set to 40%, and the film thickness was set to 100 μm to obtain a preliminary molding material; after the surface of the preliminary molding material was cleaned, it was placed in a stainless steel tray and covered with salt, and then placed in an oven, and the oven heating program was set as follows: keep warm at 90 °C for 3 hours, then increase the temperature to 150 °C and continue to keep warm for 5 hours, and finally, the salt on the surface of the material was cleaned with water to obtain tensile splines, heat deformation temperature splines and wear models.

[0127] The wear models obtained in Examples 8 to 11 and Comparative Examples 1 to 2 are as follows: Figure 2 As shown. Figure 2 It can be seen that the model in comparative example 1 cracks severely, while the other models are relatively good. This indicates that the single epoxy resin is relatively brittle after thermal curing and is prone to cracking.

[0128] The obtained tensile specimens were subjected to a tensile test: the test standard was carried out in accordance with the provisions of ASTM D638, and the test equipment was a test tensile machine.

[0129] The obtained heat deformation temperature specimens were subjected to a heat deformation temperature test: the test standard was carried out in accordance with the provisions of ASTM D648, and the test equipment was a heat deformation temperature tester.

[0130] The obtained wear model is subjected to a wear test: the test standard is carried out in accordance with the provisions of ASTM D4060; the test equipment is an abrasion tester.

[0131] The results are shown in Table 1 below.

[0132] Table 1

[0133]

[0134] Note: No data can be measured in Comparative Example 1 due to material cracking.

[0135] As can be seen from Table 1, the 3D printing materials prepared from the resin compositions provided in Examples 8-14 exhibit excellent mechanical and thermodynamic properties. This is mainly because the dual-curable polyoxazolidone prepolymer has a brand-new polymer structure and is combined with a special light-heat dual-curing process to solve the problem of easy cracking of the material while improving the material performance, and has broad application prospects in the field of industrial plastics.

[0136] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or replace some or all of the technical features therein with equivalents. However, these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A dual-curable polyoxazolidone prepolymer, characterized in that: A diol and a diisocyanate are reacted through a first reaction to generate an isocyanate-terminated polyurethane prepolymer; the isocyanate-terminated polyurethane prepolymer is reacted with an epoxy resin through a second reaction to generate a polyoxazolidone having isocyanate at both ends; and finally the polyoxazolidone having isocyanate at both ends is reacted with a blocking agent through a third reaction to obtain a dual-curable polyoxazolidone prepolymer; Wherein, the blocking agent is an aminomethyl acrylate compound.

2. The dual-curable polyoxazolidone prepolymer according to claim 1, characterized in that The aminomethylacrylate compound includes at least one of tert-butylaminoethyl methacrylate, tert-amylaminoethyl methacrylate, tert-hexylaminoethyl methacrylate and tert-butylaminopropyl methacrylate; Preferably, the diol comprises a polyether diol and / or a polyester diol; Preferably, the polyether diol comprises at least one of polyethylene glycol, polypropylene glycol and polytetramethylene glycol; Preferably, the polyester diol comprises polycaprolactone diol.

3. The dual-curable polyoxazolidone prepolymer according to claim 1, characterized in that The diisocyanate includes at least one of hexamethylene diisocyanate, isophorone diisocyanate, 4,4'-dicyclohexylmethane diisocyanate and toluene diisocyanate; Preferably, the epoxy resin includes at least one of bisphenol A diglycidyl ether, bisphenol F diglycidyl ether, 1,4-cyclohexanedicarboxylic acid diglycidyl ester, terephthalic acid diglycidyl ester and polypropylene glycol diglycidyl ether.

4. The dual-curable polyoxazolidone prepolymer according to any one of claims 1 to 3, characterized in that The temperature of the first reaction is 70-90°C and the time is 2-5h; Preferably, the catalyst used in the first reaction includes dibutyltin dilaurate; Preferably, the temperature of the second reaction is 150-170°C and the time is 2-5h; Preferably, the catalyst used in the second reaction comprises lithium chloride; Preferably, the temperature of the third reaction is 70-90° C., and the time is 0.5-2 h.

5. The dual-curable polyoxazolidone prepolymer according to any one of claims 1 to 3, characterized in that Adding a polymerization inhibitor in the third reaction; Preferably, the inhibitor comprises p-hydroxyanisole; Preferably, the molar ratio of diol, diisocyanate, epoxy resin and blocking agent is 0.5-0.8:1.6:0.25-0.5:0.5-1.

2.

6. A resin composition for 3D printing, characterized in that: According to the percentage by mass, it comprises 30-60% of a dual-curable polyoxazolidone prepolymer, 25-50% of a photocurable diluent monomer, 10-20% of a curing agent and 0.5-2% of a photoinitiator; Wherein, the dual-curable polyoxazolidone prepolymer is the dual-curable polyoxazolidone prepolymer according to any one of claims 1 to 5.

7. The resin composition according to claim 6, characterized in that The photocurable diluent monomer has at least one functionality; Preferably, the photocurable diluent monomer comprises isobornyl acrylate, isobornyl methacrylate, 1,3-propylene glycol diacrylate, 1,3-propylene glycol dimethacrylate, 1,4-butylene glycol diacrylate, 1,4-butylene glycol dimethacrylate, 1,5-pentanediol diacrylate, 1,5-pentanediol dimethacrylate, 1,6-hexanediol diacrylate, 1,6-hexanediol dimethacrylate, 1,7-heptanediol diacrylate, 1,7-heptanediol dimethacrylate, 1,8-octanediol diacrylate, 1,8-octanediol diacrylate. At least one of dimethacrylate, trimethylolpropane triol triacrylate, trimethylolpropane triol trimethacrylate, ethoxylated trimethylolpropane triol triacrylate, ethoxylated trimethylolpropane triol trimethacrylate, neopentyl glycol diacrylate, neopentyl glycol dimethacrylate, tripropylene glycol diacrylate, tripropylene glycol dimethacrylate, pentaerythritol triacrylate, pentaerythritol trimethacrylate, tricyclohexane dimethanol diacrylate, tricyclohexane dimethanol dimethacrylate and dimethylacrylamide; Preferably, the curing agent comprises at least one of an aromatic amine, an alicyclic amine and an aliphatic amine; Preferably, the aromatic amine comprises 4,4-methylenebis(2,6-diethylaniline); Preferably, the alicyclic amine comprises 3,3-dimethyl-4,4-diaminodicyclohexylmethane; Preferably, the aliphatic amine comprises a polyetheramine; Preferably, the grades of the polyetheramine include D230 and / or T403; Preferably, the photoinitiator comprises at least one of benzoin ether, dialkyl acetophenone, acylphosphine oxide and benzoylphosphine oxide.

8. The resin composition according to claim 6 or 7, characterized in that The invention also comprises a color paste with a mass percentage of 0.1 to 0.5%.

9. A method for using the resin composition according to any one of claims 6 to 8, characterized in that: The resin composition according to any one of claims 6 to 8 is loaded into a 3D light-curing printer, and light-curing printing is performed to obtain a preliminary molding material; then the preliminary molding material is thermally cured to obtain a 3D printed model.

10. The method of use according to claim 9, characterized in that: In the light-curing printing, the wavelength of the light source is 360-400 nm, the temperature is 20-35° C., the humidity is 34-45%, and the film thickness is 50-100 μm; Preferably, the thermal curing process is: firstly keep the temperature at 80-100°C for 2-4 hours, and then increase the temperature to 140-160°C and keep the temperature for 4-6 hours.

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