A plant oil-based ultraviolet light-curing resin oligomer and its preparation method and ultraviolet light-curing composition

Abstract

The present invention discloses a method for preparing a plant oil-based UV-curable resin oligomer, which uses epoxy soybean oil as a base, adds acrylic acid or methacrylic acid to undergo a catalytic ring-opening reaction under the action of a catalyst, and obtains a plant oil-based UV-curable resin oligomer. The composition of the synthesized plant oil-based UV-curable resin oligomer, reactive diluent and photoinitiator is further used for photocuring 3D printing. The plant oil-based UV-curable resin oligomer with a specific structure of the present invention is not only green and environmentally friendly and belongs to renewable energy, but also enables the objects produced by photocuring 3D to have high toughness, high hydrophobicity and good thermal stability. Moreover, the synthesized plant oil-based UV-curable resin oligomer has good compatibility with the reactive diluent, and can improve the cross-linking density of each compound in the photocuring 3D process, thereby allowing the firmware printed by photocuring 3D to have higher precision.

Description

Technical Field

[0001] The invention belongs to the technical field of photosensitive resins, and in particular relates to a green and environmentally friendly vegetable oil-based ultraviolet light-curing resin oligomer, a preparation method thereof, and an ultraviolet light-curing composition. Background Art

[0002] UV curing technology is an industrial technology with 5E characteristics, namely, efficient, economical, energy saving, enabling and environmentally friendly. It is an ideal curing method and has developed rapidly since its emergence in the 1960s. It is mainly used in technical fields such as coatings, inks and adhesives.

[0003] At present, there are relatively few types of photosensitive resins available for 3D printing on the market, and most of them are prepared and produced based on the free radical photocuring mechanism. These cured resins become hard and brittle, resulting in poor bending and tensile properties. At the same time, the printed firmware has poor precision and shrinkage, which seriously limits their application. Most of the traditional photocurable resins are produced from petroleum-based raw materials. With the increasing popularity of the concept of sustainable development and the continuous popularization of green environmental protection concepts, it is urgent to seek efficient, low-cost and renewable alternative raw materials to prepare green polymer materials. As the research on green polymer materials in the world has made great progress, the development of plant oil-based polymers has also quickly entered the field of vision of researchers. Soybean oil is one of the most common renewable green resources in human society. Epoxidized soybean oil can be quickly synthesized by epoxidation of soybean oil with an oxidant. The process is simple and the yield is high. In addition, the non-volatility, excellent thermal stability and light stability of epoxidized soybean oil and good miscibility with resin materials make it have important research significance in the field of resin synthesis. Compared with other photocurable resins, this type of resin prepared by epoxidizing soybean oil is cheap, green and environmentally friendly, has low viscosity and good flexibility. In summary, it is urgent to develop a green, environmentally friendly, renewable plant oil-based resin for photocurable 3D printing. Summary of the invention

[0004] The invention provides a vegetable oil-based photocurable resin oligomer and a preparation method thereof and an ultraviolet light-curable composition, so as to solve the defects of poor mechanical properties, large shrinkage, poor printing accuracy and the like of printed firmware in a traditional photocurable system, and save energy and be renewable.

[0005] To solve the above problems, the present invention is implemented through the following technical solutions:

[0006] The present invention first provides a method for preparing a plant oil-based ultraviolet light-curable resin oligomer, comprising the following steps:

[0007] (1) Under an inert atmosphere, a certain amount of epoxidized soybean oil and an inhibitor are mixed and dispersed (mechanically stirred at 180-250 r / min) at 80-100°C (oil bath) to form a uniform solution A;

[0008] (2) Add a certain amount of catalyst to the monomer and disperse it at 20-40°C to form a uniform solution B;

[0009] (3) Under an inert atmosphere, the solution B is slowly added dropwise into the solution A. After the solution B is completely added dropwise, the temperature of the reaction system is adjusted to 110-130° C. and the mixture is evenly dispersed (the mechanical stirring rate is adjusted to 400-500 r / min). After reacting for 5-6 hours, a vegetable oil-based UV-curable resin oligomer is obtained.

[0010] Furthermore, the chemical structure of the epoxidized soybean oil is as follows: ) as shown:

[0011]

[0012] Mode( ).

[0013] Furthermore, in step (1), the amount of the polymerization inhibitor used is 0.1 wt% to 0.2 wt% of the amount of the epoxidized soybean oil used.

[0014] Furthermore, in step (1), the polymerization inhibitor is selected from at least one of hydroquinone, p-methoxyphenol, o-methylhydroquinone and 2,6-di-tert-butyl-4-methylphenol; in step (2), the catalyst is selected from at least one of phosphine, triphenylphosphine, bis(triphenylphosphine)palladium diacetate, iodine and potassium iodide.

[0015] Furthermore, in step (2), the monomer is at least one of acrylic acid and methacrylic acid.

[0016] Furthermore, in step (2), the amount of the catalyst used is 1wt% to 2wt% of the amount of the epoxidized soybean oil used in step (1); and the molar ratio between the carboxyl group in the monomer used and the epoxy group in the epoxidized soybean oil used in step (1) is 1:1.05-1.25.

[0017] Another object of the present invention is to provide a plant oil-based ultraviolet light-curable resin oligomer prepared by the above method.

[0018] The present invention also provides an ultraviolet light curing composition, comprising the above-mentioned vegetable oil-based ultraviolet light curing resin oligomer, a reactive diluent and a photoinitiator.

[0019] Furthermore, the raw materials are included in the following weight percentages: 45-50% of the plant oil-based UV-curable resin oligomer, 48-53% of the active diluent, and 1-3% of the photoinitiator.

[0020] Furthermore, the active diluent is selected from at least one of acryloyl morpholine (ACMO), trimethylolpropane triacrylate (TMPTA), 1,6-hexanediol diacrylate (HDDA), polyethylene glycol diacrylate (PEGDA), isobornyl acrylate (IBOA), and pentaerythritol triacrylate (PETA); and the photoinitiator is selected from at least one of Irgacure 819, Irgacure 261, and TPO.

[0021] Since the triglycerides in the vegetable oil-based UV-curable resin oligomers will increase the viscosity of the oligomers, a large proportion of acrylate monomers or other monomers are required in the photocuring active diluent selection. During the photocuring process, the triglycerides in the epoxidized soybean oil react with the acrylates in the active diluents in the photocuring system to form heat-cured crosslinks, and a resin material with better flexibility, thermal stability, light stability and printing accuracy is formed through the light-heat dual curing method.

[0022] The present invention has the following positive and beneficial effects:

[0023] (1) The vegetable oil-based UV-curable resin of the present invention is a vegetable oil-based acrylate synthesized by an open-chain reaction of acrylic acid or methacrylic acid as a monomer and epoxidized soybean oil, which can be used as a main resin. The triglyceride and other acrylate active diluents undergo cross-linking reaction through the exothermic temperature rise during the curing and cross-linking process during the photocuring process, and finally a tight cross-linking structure is formed, thereby greatly improving the flexibility, light and heat stability and printing resolution of the material.

[0024] (2) The plant oil-based UV-curable resin of the present invention can be directly used as a prepolymer of a photocurable resin. After reacting it with a reactive diluent, it can enhance multiple mechanical properties of the photocurable 3D printing resin, thereby making up for the shortcomings of the existing resins such as high shrinkage, brittle and easy-to-break printing firmware, and poor printing accuracy, making 3D printing materials easier to obtain. At the same time, the plant oil-based UV-curable resin of the present invention can gradually replace traditional petroleum-based photocurable resins, thereby reducing the cost of 3D printing materials and energy waste.

[0025] (3) The vegetable oil-based UV-curable resin of the present invention has a higher viscosity due to the addition of triglyceride, and is more suitable for dilution and mixing with an active diluent having good dilution performance. It has very good compatibility with a variety of resins or monomers, and the cured product has excellent properties. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 It is the FTIR spectrum analysis diagram of Example 1 and Comparative Example 1;

[0027] Figure 2 is a SEM image of the epoxy soybean oil acrylate vegetable oil-based resin composition of Example 1;

[0028] Figure 3 is a contact angle diagram of the epoxy soybean oil acrylate vegetable oil-based resin composition of Example 1;

[0029] Figure 4 This is a photocurable 3D printing sample image of the epoxy soybean oil acrylate vegetable oil-based resin composition of Example 1. DETAILED DESCRIPTION

[0030] The following examples further describe the present invention in detail, but the embodiments of the present invention are not limited to these examples. Unless otherwise specified, the reagents used in the examples of the present invention are all conventional raw materials or reagents, and the experimental methods used are all conventional methods in the art unless otherwise specified.

[0031] Example 1

[0032] As the formula ( ) 50.00g of epoxy soybean oil with the structure shown in Figure 2 and 0.1g of inhibitor hydroquinone were added to a four-necked flask equipped with a thermometer, condenser, dropping funnel and stirring paddle, and mixed and stirred for 15 minutes in a 90℃ oil bath and 200 r / min mechanical stirring conditions until solution A was completely uniform. 12.87g of acrylic acid was weighed in a beaker and 0.75g of catalyst triphenylphosphine was added. The beaker was placed in a 60℃ constant temperature water bath for magnetic stirring to form a homogeneous solution B. Then, solution B was slowly dripped into solution A. After the dripping was completed, the reaction temperature was raised to 120℃ and the mechanical stirring rate was increased to 450 r / min. After the reaction for 5.5 hours, an oligomer epoxy soybean oil acrylate with a molar ratio of carboxyl groups in acrylic acid to epoxy groups in epoxy soybean oil of 1:1.05 was obtained.

[0033] The epoxy soybean oil acrylate vegetable oil-based resin obtained above is added with a reactive diluent, a reactive diluent and a photoinitiator to prepare an epoxy soybean oil acrylate vegetable oil-based photocurable composition. The specific weight percentage ratio is: 48% of the above epoxy soybean oil acrylate vegetable oil-based photocurable resin, 30% of acryloyl morpholine (ACMO), 20% of 1,6 hexanediol diacrylate (HDDA), and 2% of photoinitiator 819; the above raw materials are stirred and mixed evenly to obtain a material for photocurable 3D printing.

[0034] Example 2

[0035] As the formula ( ) 50.00g of epoxy soybean oil with the structure shown in Figure 2 and 0.1g of inhibitor hydroquinone were added to a four-necked flask equipped with a thermometer, condenser, dropping funnel and stirring paddle, and mixed and stirred for 15 minutes in a 90℃ oil bath and 200 r / min mechanical stirring conditions until solution A was completely uniform. 12.28g of acrylic acid was weighed in a beaker and 0.75g of catalyst triphenylphosphine was added. The beaker was placed in a 60℃ constant temperature water bath for magnetic stirring to form a homogeneous solution B. Then, solution B was slowly dripped into solution A. After the dripping was completed, the reaction temperature was raised to 120℃ and the mechanical stirring rate was increased to 450 r / min. After the reaction for 5.5 hours, an oligomer epoxy soybean oil acrylate with a molar ratio of carboxyl groups in acrylic acid to epoxy groups in epoxy soybean oil of 1:1.10 was obtained.

[0036] The epoxy soybean oil acrylate vegetable oil-based resin obtained above is added with a reactive diluent, a reactive diluent and a photoinitiator to prepare an epoxy soybean oil acrylate vegetable oil-based photocurable composition. The specific weight percentage ratio is: 48% of the above epoxy soybean oil acrylate vegetable oil-based photocurable resin, 30% of acryloyl morpholine (ACMO), 20% of 1,6 hexanediol diacrylate (HDDA), and 2% of photoinitiator 819; the above raw materials are stirred and mixed evenly to obtain a material for photocurable 3D printing.

[0037] Example 3

[0038] As the formula ( ) 50.00g of epoxy soybean oil with the structure shown in Figure 2 and 0.1g of inhibitor hydroquinone were added to a four-necked flask equipped with a thermometer, condenser, dropping funnel and stirring paddle, and mixed and stirred for 15min in a 90℃ oil bath and 200 r / min mechanical stirring conditions until solution A was completely uniformly formed. 11.75g ​​of acrylic acid was weighed in a beaker and 0.75g of catalyst triphenylphosphine was added. The beaker was placed in a 60℃ constant temperature water bath for magnetic stirring to form a homogeneous solution B. Then, solution B was slowly dripped into solution A. After the dripping was completed, the reaction temperature was raised to 120℃ and the mechanical stirring rate was increased to 450 r / min. After the reaction for 5.5 hours, an oligomer epoxy soybean oil acrylate with a molar ratio of carboxyl groups in acrylic acid to epoxy groups in epoxy soybean oil of 1:1.15 was obtained.

[0039] The epoxy soybean oil acrylate vegetable oil-based resin obtained above is added with a reactive diluent, a reactive diluent and a photoinitiator to prepare an epoxy soybean oil acrylate vegetable oil-based photocurable composition. The specific weight percentage ratio is: 48% of the above epoxy soybean oil acrylate vegetable oil-based photocurable resin, 30% of acryloyl morpholine (ACMO), 20% of 1,6 hexanediol diacrylate (HDDA), and 2% of photoinitiator 819; the above raw materials are stirred and mixed evenly to obtain a material for photocurable 3D printing.

[0040] Example 4

[0041] As the formula ( ) 50.00g of epoxy soybean oil with the structure shown in Figure 2 and 0.1g of inhibitor hydroquinone were added to a four-necked flask equipped with a thermometer, condenser, dropping funnel and stirring paddle, and mixed and stirred for 15min in a 90℃ oil bath and 200 r / min mechanical stirring conditions until solution A was completely uniformly formed. 11.26g of acrylic acid was weighed into a beaker and 0.75g of catalyst triphenylphosphine was added. The beaker was placed in a 60℃ constant temperature water bath for magnetic stirring to form a homogeneous solution B. Then, solution B was slowly dripped into solution A. After the dripping was completed, the reaction temperature was raised to 120℃ and the mechanical stirring rate was increased to 450 r / min. After the reaction for 5.5 hours, an oligomer epoxy soybean oil acrylate with a molar ratio of carboxyl groups in acrylic acid to epoxy groups in epoxy soybean oil of 1:1.20 was obtained.

[0042] The epoxy soybean oil acrylate vegetable oil-based resin obtained above is added with a reactive diluent, a reactive diluent and a photoinitiator to prepare an epoxy soybean oil acrylate vegetable oil-based photocurable composition. The specific weight percentage ratio is: 48% of the above epoxy soybean oil acrylate vegetable oil-based photocurable resin, 30% of acryloyl morpholine (ACMO), 20% of 1,6 hexanediol diacrylate (HDDA), and 2% of photoinitiator 819; the above raw materials are stirred and mixed evenly to obtain a material for photocurable 3D printing.

[0043] Example 5

[0044] As the formula ( ) 50.00g of epoxy soybean oil with the structure shown in Figure 2 and 0.1g of inhibitor hydroquinone were added to a four-necked flask equipped with a thermometer, condenser, dropping funnel and stirring paddle, and mixed and stirred for 15 minutes in a 90℃ oil bath and 200 r / min mechanical stirring conditions until solution A was completely uniform. 10.81g of acrylic acid was weighed in a beaker and 0.75g of catalyst triphenylphosphine was added. The beaker was placed in a 60℃ constant temperature water bath for magnetic stirring to form a homogeneous solution B. Then, solution B was slowly added dropwise to solution A. After the addition was completed, the reaction temperature was raised to 120℃ and the mechanical stirring rate was increased to 450 r / min. After the reaction for 5.5 hours, an oligomer epoxy soybean oil acrylate with a molar ratio of carboxyl groups in acrylic acid to epoxy groups in epoxy soybean oil of 1:1.25 was obtained.

[0045] The epoxy soybean oil acrylate vegetable oil-based resin obtained above is added with a reactive diluent, a reactive diluent and a photoinitiator to prepare an epoxy soybean oil acrylate vegetable oil-based photocurable composition. The specific weight percentage ratio is: 48% of the above epoxy soybean oil acrylate vegetable oil-based photocurable resin, 30% of acryloyl morpholine (ACMO), 20% of 1,6 hexanediol diacrylate (HDDA), and 2% of photoinitiator 819; the above raw materials are stirred and mixed evenly to obtain a material for photocurable 3D printing.

[0046] Example 6

[0047] 50.00 g of epoxy soybean oil with the structure shown in formula (I) and 0.1 g of inhibitor hydroquinone were added to a four-necked flask equipped with a thermometer, a condenser, a dropping funnel and a stirring paddle, and mixed and stirred for 15 min in a 90°C oil bath and 200 r / min mechanical stirring conditions until a completely uniform solution A was formed. 15.37 g of methacrylic acid was weighed in a beaker and 0.75 g of catalyst triphenylphosphine was added. The beaker was placed in a 60°C constant temperature water bath and magnetically stirred to form a homogeneous solution B. Then, solution B was slowly dripped into solution A. After the dripping was completed, the reaction temperature was raised to 120°C and the mechanical stirring rate was increased to 450 r / min. After the reaction for 5.5 h, an oligomer epoxy soybean oil methacrylate with a molar ratio of carboxyl groups in methacrylic acid to epoxy groups in epoxy soybean oil of 1:1.05 was obtained.

[0048] The epoxy soybean oil methacrylate vegetable oil-based resin obtained above is added with active diluent, active diluent and photoinitiator to prepare an epoxy soybean oil methacrylate vegetable oil-based photocurable composition. The specific weight percentage ratio is: 48% of the above epoxy soybean oil methacrylate vegetable oil-based photocurable resin, 30% of acryloyl morpholine (ACMO), 20% of 1,6 hexanediol diacrylate (HDDA), and 2% of photoinitiator 819; the above raw materials are stirred and mixed evenly to obtain a material for photocurable 3D printing.

[0049] Example 7

[0050] 50.00 g of epoxy soybean oil with the structure shown in formula (I) and 0.1 g of inhibitor hydroquinone were added to a four-necked flask equipped with a thermometer, a condenser, a dropping funnel and a stirring paddle, and mixed and stirred for 15 min in a 90°C oil bath and 200 r / min mechanical stirring conditions until a completely uniform solution A was formed. 14.67 g of methacrylic acid was weighed in a beaker and 0.75 g of the catalyst triphenylphosphine was added. The beaker was placed in a 60°C constant temperature water bath and magnetically stirred to form a homogeneous solution B. Then, solution B was slowly dripped into solution A. After the dripping was completed, the reaction temperature was raised to 120°C and the mechanical stirring rate was increased to 450 r / min. After the reaction for 5.5 h, an oligomer epoxy soybean oil methacrylate with a molar ratio of carboxyl groups in methacrylic acid to epoxy groups in epoxy soybean oil of 1:1.10 was obtained.

[0051] The epoxy soybean oil methacrylate vegetable oil-based resin obtained above is added with active diluent, active diluent and photoinitiator to prepare an epoxy soybean oil methacrylate vegetable oil-based photocurable composition. The specific weight percentage ratio is: 48% of the above epoxy soybean oil methacrylate vegetable oil-based photocurable resin, 30% of acryloyl morpholine (ACMO), 20% of 1,6 hexanediol diacrylate (HDDA), and 2% of photoinitiator 819; the above raw materials are stirred and mixed evenly to obtain a material for photocurable 3D printing.

[0052] Example 8

[0053] 50.00 g of epoxy soybean oil with the structure shown in formula (I) and 0.1 g of inhibitor hydroquinone were added to a four-necked flask equipped with a thermometer, a condenser, a dropping funnel and a stirring paddle, and mixed and stirred for 15 min in a 90°C oil bath and 200 r / min mechanical stirring conditions until a completely uniform solution A was formed. 14.03 g of methacrylic acid was weighed in a beaker and 0.75 g of the catalyst triphenylphosphine was added. The beaker was placed in a 60°C constant temperature water bath and magnetically stirred to form a homogeneous solution B. Then, solution B was slowly dripped into solution A. After the dripping was completed, the reaction temperature was raised to 120°C and the mechanical stirring rate was increased to 450 r / min. After the reaction for 5.5 h, an oligomer epoxy soybean oil methacrylate with a molar ratio of carboxyl groups in methacrylic acid to epoxy groups in epoxy soybean oil of 1:1.15 was obtained.

[0054] The epoxy soybean oil methacrylate vegetable oil-based resin obtained above is added with active diluent, active diluent and photoinitiator to prepare an epoxy soybean oil methacrylate vegetable oil-based photocurable composition. The specific weight percentage ratio is: 48% of the above epoxy soybean oil methacrylate vegetable oil-based photocurable resin, 30% of acryloyl morpholine (ACMO), 20% of 1,6 hexanediol diacrylate (HDDA), and 2% of photoinitiator 819; the above raw materials are stirred and mixed evenly to obtain a material for photocurable 3D printing.

[0055] Example 9

[0056] 50.00 g of epoxy soybean oil with the structure shown in formula (I) and 0.1 g of inhibitor hydroquinone were added to a four-necked flask equipped with a thermometer, a condenser, a dropping funnel and a stirring paddle, and mixed and stirred for 15 min in a 90°C oil bath and 200 r / min mechanical stirring conditions until a completely uniform solution A was formed. 13.45 g of methacrylic acid was weighed in a beaker and 0.75 g of the catalyst triphenylphosphine was added. The beaker was placed in a 60°C constant temperature water bath and magnetically stirred to form a homogeneous solution B. Then, solution B was slowly dripped into solution A. After the dripping was completed, the reaction temperature was raised to 120°C and the mechanical stirring rate was increased to 450 r / min. After the reaction for 5.5 h, an oligomer epoxy soybean oil methacrylate with a molar ratio of carboxyl groups in methacrylic acid to epoxy groups in epoxy soybean oil of 1:1.20 was obtained.

[0057] The epoxy soybean oil methacrylate vegetable oil-based resin obtained above is added with active diluent, active diluent and photoinitiator to prepare an epoxy soybean oil methacrylate vegetable oil-based photocurable composition. The specific weight percentage ratio is: 48% of the above epoxy soybean oil methacrylate vegetable oil-based photocurable resin, 30% of acryloyl morpholine (ACMO), 20% of 1,6 hexanediol diacrylate (HDDA), and 2% of photoinitiator 819; the above raw materials are stirred and mixed evenly to obtain a material for photocurable 3D printing.

[0058] Example 10

[0059] 50.00 g of epoxy soybean oil with the structure shown in formula (I) and 0.1 g of inhibitor hydroquinone were added to a four-necked flask equipped with a thermometer, a condenser, a dropping funnel and a stirring paddle, and mixed and stirred for 15 min in a 90°C oil bath and 200 r / min mechanical stirring conditions until a completely uniform solution A was formed. 12.91 g of methacrylic acid was weighed in a beaker and 0.75 g of catalyst triphenylphosphine was added. The beaker was placed in a 60°C constant temperature water bath and magnetically stirred to form a homogeneous solution B. Then, solution B was slowly dripped into solution A. After the dripping was completed, the reaction temperature was raised to 120°C and the mechanical stirring rate was increased to 450 r / min. After the reaction for 5.5 h, an oligomer epoxy soybean oil methacrylate with a molar ratio of carboxyl groups in methacrylic acid to epoxy groups in epoxy soybean oil of 1:1.25 was obtained.

[0060] The epoxy soybean oil methacrylate vegetable oil-based resin obtained above is added with active diluent, active diluent and photoinitiator to prepare an epoxy soybean oil methacrylate vegetable oil-based photocurable composition. The specific weight percentage ratio is: 48% of the above epoxy soybean oil methacrylate vegetable oil-based photocurable resin, 30% of acryloyl morpholine (ACMO), 20% of 1,6 hexanediol diacrylate (HDDA), and 2% of photoinitiator 819; the above raw materials are stirred and mixed evenly to obtain a material for photocurable 3D printing.

[0061] The performance test of the materials obtained in the above examples is as follows:

[0062] (1) Viscosity test: The viscosity of the synthesized epoxy soybean oil-based acrylate product was measured using a NDJ-5S rotational viscometer with a No. 2 rotor. The rotational viscometer was equipped with a constant temperature water bath and the test temperature was 25°C.

[0063] (2) Esterification rate test: The determination of monomer esterification rate is carried out in accordance with the standard GB 2895-1982, where c is the concentration of KOH ethanol solution, V is the volume of KOH ethanol solution consumed, and the mass of the sample taken is recorded as m 1, the amount of monomer added to the reaction is recorded as n, and the total mass of the reactants is recorded as m 0 , then the esterification rate of the monomer in the reaction system is calculated as follows: ES (%) = (1-(c × V × m 1 ×m 0 ) / (n×1000))×100%.

[0064] (3) Gel rate test: Use a 405nm LED UV curing lamp to irradiate the liquid resin in the sample tank, take 0.8-1.0g of the cured resin sample, and record the weight of the sample as W. 1 , put the sample into Soxhlet extractor, extract with acetone for 12h, take out the remaining solidified resin after extraction, put it into drying oven to dry until the sample has constant weight, and the mass of the sample is recorded as W 2 The formula for calculating the gel fraction (GC) of the resin is: GC (%) = W 2 / W 1 ×100%.

[0065] (4) Infrared test: AVATAR 360ESP Fourier transform infrared spectrometer was used to characterize the infrared absorption peak of the resin.

[0066] (5) SEM test of resin composition: The 3D printed bending test specimens of the vegetable oil-based UV-curable resin were frozen in liquid nitrogen and then dried and gold-sprayed. The cross-sectional morphology was observed using an EVO 18 scanning electron microscope. The test conditions were 25°C, an accelerating voltage of 20 kV, and a magnification of 1000-5000 times.

[0067] (6) Contact angle test: At 25°C, the contact angle test of the cured resin 3D printed disc was carried out using an OCA-20 contact angle meter. The wetting medium was deionized water, and the sessile drop method was used.

[0068] Table 1 Related test results

[0069]

[0070] From the viscosity test results in Table 1, it can be seen that the oligomer of the vegetable oil-based UV-curable resin obtained by the above embodiment has good viscosity and is very suitable for UV-curable 3D printing.

[0071] From the remaining esterification rate and gel rate test results in Table 1, it can be seen that as the molar ratio of epoxy group to carboxyl group increases, the esterification rate of acrylic acid gradually increases. After the molar ratio of epoxy group to carboxyl group is greater than 1.15, the esterification rate does not change much; and as the molar ratio of epoxy group to carboxyl group increases, the viscosity of epoxy soybean oil acrylate also gradually increases, and the growth rate also gradually increases. The overall esterification rate and gel rate of Examples 1-5 are higher than those of Examples 6-10. As the molar ratio of epoxy group in epoxy soybean oil to carboxyl group in acrylic acid increases, the gel rate also increases.

[0072] from Figure 1 From the FTIR spectrum analysis chart of infrared test, we can see that Figure 1 Curves (a) and (b) are the infrared spectra of acrylic acid and methacrylic acid, respectively. Curve (c) is the infrared spectrum of epoxidized soybean oil. Curves (d) and (e) are the infrared spectra of the products synthesized using acrylic acid and methacrylic acid as reaction monomers. -1 There are multiple absorption peaks in the range of 1629cm -1 The stretching vibration peak of the carbon-carbon double bond is at 1629cm, which has obvious absorption peaks in curves (a) and (b), and can also be observed in curves (d) and (e). -1 The absorption peak of curves (c) to (e) is at 1739 cm -1 The characteristic peak that appears nearby is the carbonyl absorption peak of acrylate, indicating that the monomer has successfully reacted to acrylate the epoxy soybean oil. The product contains acrylate groups, and the carbon-carbon double bonds therein make the reaction product also suitable for LCD 3D printing based on free radical photocuring reaction.

[0073] from Figure 2 From the SEM test results, it can be seen that a typical peak morphology can be observed in the cross-section of the vegetable oil-based photocurable resin sample, which shows the propagation and accelerated diffusion of tensile cracks, indicating that the energy of the cured resin is dispersed during the stretching process and has an obvious layered structure, indicating that the cured network of the cured resin is dense and has good toughness.

[0074] from Figure 3 The contact angle test results show that the contact angle of the surface of the vegetable oil-based photocurable resin sample is 91°, indicating that the triglyceride groups provided in the UV vegetable oil-based oligomer synthesized in the present invention will make the 3D printed firmware have better hydrophobic properties.

[0075] from Figure 4It can be seen from the printed sample pictures that the two resins have high molding accuracy and high model resolution, which means that the epoxy soybean oil-based photocurable resin of this system is also suitable for LCD printing of high-precision and high-complexity models, and can meet the material requirements of DLP or LCD printers on the market.

[0076] This shows that in the reaction process with epoxidized soybean oil, the product obtained by using acrylic acid as a monomer is more suitable for photocurable 3D printing than that obtained by using methacrylic acid as a monomer. As the molar ratio of epoxy groups in epoxidized soybean oil to carboxyl groups in acrylic acid increases, the curing rate of the vegetable oil-based photocurable resin also increases. This is because the more acrylate groups on the epoxidized soybean oil, the better the curing and crosslinking degree of the resin under ultraviolet irradiation. At the same time, due to the characteristics of epoxidized soybean oil containing triglycerides, a 3D printing firmware with high toughness, high hydrophobicity and good thermal stability can be obtained in the end.

[0077] The above examples and comparative examples are used to explain the embodiments of the present invention and do not exceed the scope of the subject matter of the present invention. The protection scope of the present invention is not limited by the examples. Unless otherwise specified, the materials and reagents used in the present invention can be obtained from commercial products in the field.

Claims

1. A UV-curable composition for 3D printing, It is characterized in that The invention comprises the following raw materials in percentage by weight: 48% of vegetable oil-based ultraviolet light-curable resin oligomer, 30% of acryloyl morpholine, 20% of 1,6-hexanediol diacrylate, and 2% of photoinitiator 819; The vegetable oil-based UV-curable resin oligomer is prepared by the following steps: (1) The epoxy soybean oil of the structure shown in formula (I) and the inhibitor hydroquinone are mixed and stirred for 15 minutes in an oil bath at 90°C and mechanically stirred at 200 r / min until a solution A is completely uniformly formed, wherein the amount of the inhibitor is 0.2 wt% of the amount of the epoxy soybean oil; (2) Weigh acrylic acid and add triphenylphosphine catalyst, place in a 60°C constant temperature water bath and stir magnetically to form a homogeneous solution B, wherein the molar ratio between the carboxyl group in the acrylic acid and the epoxy group in the epoxidized soybean oil is 1:1.1; the amount of the catalyst used is 1.5 wt% of the amount of the epoxidized soybean oil used in step (1); (3) Solution B was slowly added dropwise into solution A. After the addition was completed, the reaction temperature was raised to 120°C, the mechanical stirring rate was increased to 450 r / min, and after reacting for 5.5 h, a plant oil-based UV-curable resin oligomer was obtained; The chemical structure of the epoxidized soybean oil is shown in formula (I): Formula (I).

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