Transparent UV ink composition suitable for ink-jet 3D printing and preparation method thereof

Abstract

The invention discloses a transparent UV ink composition suitable for ink-jet 3D printing and a preparation method thereof, 100 parts by mass of the transparent UV ink composition comprises the following components by mass: 10-20 parts of a prepolymer resin which is aliphatic acrylate resin with a functionality of 2 or more; 66-77 parts of a diluting monomer, the diluting monomer comprises a monofunctional monomer and a polyfunctional monomer, and the mass part ratio of the monofunctional monomer to the polyfunctional monomer is (1-3): 1; the invention relates to a photocurable resin composition which comprises the following components in parts by weight: 10-16 parts of non-reactive resin, 1-2 parts of a photoinitiator and 0.01-0.1 part of a polymerization inhibitor, and the polymerization inhibitor is a phenolic polymerization inhibitor. The ink composition can be stably jetted at the temperature of 50 DEG C or above, and the jetting performance is good; the transparency of the material is high, and the yellowing is better; the material shrinkage rate is low.

Description

Technical Field

[0001] The present invention relates to the technology of photocuring 3D printing, and particularly to a transparent UV ink composition applicable to inkjet 3D printing and a preparation method thereof. Background Art

[0002] Conventional technical methods of photocuring 3D printing generally mainly include digital light processing technology (DLP), liquid crystal display technology (LCD), and stereolithography (SLA). However, these methods can only print in single color, and for printing colorful models, post-coloring is required, which increases the process. The 3D printing method using an inkjet print head for UV curing can achieve multiple colors simultaneously. Currently, there are not many manufacturers using inkjet UV 3D printing. The main representatives abroad are Stratasys and MIMAKI. However, the material ejection temperature used is relatively high, basically above 70°C. High temperature requires high equipment requirements, is not conducive to the service life of the equipment, and has a high risk of stable printing. At the same time, for inkjet UV 3D printing, since the inkjet printing stacking process is carried out in the air, the oxygen inhibition polymerization of the photosensitive material during the printing process is large, and it is easy to turn yellow. Conventional methods for improving yellowing are likely to cause the material to shrink, which not only affects the light transmittance of the printed model, but also the yellowing will affect the color effect of the colorful model after adding dyes. Summary of the Invention

[0003] To solve the above technical problems, the present invention provides a transparent UV ink composition applicable to inkjet 3D printing and a preparation method thereof. Through the synergistic effect of monofunctional monomers, polyfunctional monomers, and a low content of photoinitiator, and at the same time, in combination with a prepolymer resin with low yellowing and a non-reactive resin filler with good compatibility, the ink can be stably ejected at a temperature of 50°C and above, and has good ejection performance; the material has high transparency and good yellowing; the material shrinkage rate is low, and the shrinkage rate of the material after molding is 5%-7%.

[0004] The present invention adopts the following technical solutions:

[0005] A transparent UV ink composition applicable to inkjet 3D printing, based on 100 parts by mass, comprises the following components in parts by mass:

[0006] 10-20 parts of prepolymer resin, and the prepolymer is an aliphatic acrylate resin with 2 or more functional groups;

[0007] 66-77 parts of diluent monomer, the diluent monomer includes monofunctional monomer and polyfunctional monomer, and the mass ratio of the monofunctional monomer to the polyfunctional monomer is 1-3:1;

[0008] 10-16 parts of non-reactive resin,

[0009] 1-2 parts of photoinitiator,

[0010] 0.01-0.1 part of inhibitor, and the inhibitor is a phenolic inhibitor.

[0011] The prepolymer resin refers to the resin component with a relatively large molecular weight in the formulation. As a structural component of the formulation, it affects the mechanical properties, transparency, aging resistance, etc. of the printed model. In the present invention, an aliphatic acrylate resin with good compatibility and performance matching with the diluent monomer is selected. The performance indexes of the prepolymer include prepolymer functionality and viscosity. The selected prepolymer resin functionality includes bifunctional, trifunctional, and multifunctional (more than trifunctional). Lower functionality results in a slower reaction rate, and the higher the functionality, the more severe the shrinkage of the material after printing.

[0012] Preferably, the prepolymer is a bifunctional aliphatic polyurethane acrylate resin.

[0013] Viscosity is one of the most important indexes in the inkjet 3D printing process. A lower viscosity is beneficial to the spraying performance during printing, but a lower viscosity will result in a relatively low overall molecular weight and poor mechanical properties of the printed model. A higher viscosity is beneficial to the mechanical properties of the model, but it will cause unsmooth spraying during printing. The viscosity range of the selected prepolymer resin at 25 °C is 5000 mPas - 100000 mPas, preferably 10000 - 20000 mPas at 25 °C.

[0014] The selected prepolymer resins include GENOMER*4256, GENOMER*4247, GENOMER*4212, GENOMER*4297, GENOMER*4316, GENOMER*4425, GENOMER*4690 of RAHN Company; BR-952, BR-970 of DYMAX Company; 6112-100, 6113 of Changxing Chemical Industry. The preferred prepolymer resins are GENOMER*4247, GENOMER*4212 of RAHN Company, BR-970 of DYMAX Company, and 6113 of Changxing Chemical Industry.

[0015] The parameters of each prepolymer resin are shown in Table 1:

[0016] Table 1 Parameters of the prepolymer resin used

[0017]

[0018] The diluent monomer is a small molecule containing polymerizable functional groups. The functions of the diluent monomer include dissolving and diluting the prepolymer resin, adjusting the viscosity of the system, and participating in the photocuring reaction process. The diluent monomer affects the photocuring speed of the ink and the properties of the film formed.

[0019] Important indicators of the diluting monomer include the functionality and viscosity of the diluting monomer.

[0020] The functionality of the diluting monomer is a combination of a monofunctional monomer and a polyfunctional monomer. The polyfunctional monomer refers to a monomer with 2 or 3 functionalities. With the monofunctional monomer as the main component, the monofunctional monomer is selected for its fast reaction rate, low shrinkage rate of the system, and easy control of the system viscosity without being too high. Adding a small amount of polyfunctional monomer under the condition of mainly using monofunctional monomer can still maintain a high reaction rate under the condition of low initiator dosage.

[0021] Preferably, the monofunctional monomer is one or more of morpholine acrylate, dimethylacrylamide, tetrahydrofuran acrylate, trimethylolpropane formal acrylate, phenoxyethyl acrylate, 2-ethoxyethyl 2-acrylate, diethylacrylamide, isobornyl acrylate.

[0022] Preferably, the polyfunctional monomer is one or more of tricyclodecane dimethanol diacrylate, dipropylene glycol diacrylate, tripropylene glycol diacrylate, trimethylolpropane triacrylate, (3-propoxy) glycerol triacrylate.

[0023] Furthermore, the mass ratio of the monofunctional monomer to the polyfunctional monomer is preferably 2:1.

[0024] The parameters of the diluting monomer are shown in Table 2:

[0025] Parameters of the diluting monomer used in Table 2

[0026]

[0027] The main function of the non-reactive resin is to reduce shrinkage. Since the proportion of the diluting monomer in the UV inkjet system is large and it contains polyfunctional monomers, the shrinkage rate of the system will be large without adding fillers. Therefore, adding a certain proportion of non-reactive resin can well improve the shrinkage rate of the system. If the proportion of non-reactive resin is too low, the effect is not obvious; if the proportion is too high, it will affect the curing rate. The optimal proportion is 10-16%.

[0028] The selection of the non-reactive resin mainly considers its compatibility with the prepolymer resin and the diluting monomer. At the same time, the non-reactive resin also affects transparency.

[0029] Preferably, the non-reactive resin is a polyacrylic resin with good compatibility with the system.

[0030] More preferably, the non-reactive resin is a polymer of methyl methacrylate and butyl methacrylate, a methyl methacrylate polymer or a methyl isobutyl methacrylate polymer with a relative molecular weight of 60,000-80,000. For example, those of Evonik 64 / 12N, LP 65 / 12 and P 28N, preferably LP 65 / 12.

[0031] The parameters of the selected non-reactive resin are shown in Table 3:

[0032] Parameters of the non-reactive resin used in Table 3

[0033]

[0034] A photoinitiator is a substance that can absorb radiant energy, undergo chemical changes after excitation, and generate active intermediates with the ability to initiate polymerization. It is a key component of UV inks and plays a decisive role in the curing speed of photocurable inks.

[0035] Preferably, the photoinitiator is a free radical type I photoinitiator 819, TPO or TPO-L. More preferably, the photoinitiator is TPO.

[0036] The main function of the inhibitor is to prevent the polymerization of the ink system under non-use conditions. The inhibitor mainly selected in the present invention is a non-yellowing phenolic inhibitor.

[0037] Preferably, the inhibitor is 2,4-dimethyl-6-tert-butylphenol, p-methoxyphenol or piperidine alcohol oxide. More preferably, the inhibitor is p-methoxyphenol.

[0038] Preferably, the transparent UV ink composition further comprises 0.01-0.1 parts of a stabilizer, and the stabilizer is one or two of aerobic inhibition type and anaerobic inhibition type. The main function of the stabilizer is to ensure the stability of the ink during storage. It can be the GENORAD series stabilizers of RAHN company. This series of stabilizers can not only achieve good storage stability, but also increase the transparency of the system, such as GENORAD*16, GENORAD*18 and GENORAD*20. More preferably, it is GENORAD*20.

[0039] Preferably, the transparent UV ink composition further comprises 0.01-0.1 parts of a leveling agent, and the leveling agent is a polyacrylate leveling agent, an organosilicon resin leveling agent or a fluororesin surfactant leveling agent. Preferably, it is an organosilicon resin leveling agent. The main function of the leveling agent is to improve the fluidity of the ink during spraying, so that a flat, smooth and uniform ink layer can be formed on the surface of the ink layer during the jet printing and forming process. The organosilicon leveling agent has good compatibility with the ink system of the present application. The leveling agent can be the leveling agents BYK-333, BYK-371, BYK-377, etc. of BYK Chemie. More preferably, it is BYK377.

[0040] The present invention also provides a method for preparing the transparent UV ink composition suitable for inkjet 3D printing as described above, comprising the following steps:

[0041] Weigh the prepolymer resin, diluent monomer, non-reactive resin, photoinitiator, inhibitor, stabilizer, and leveling agent required by the formula according to the ratio, and then use a high-speed mixer to fully stir at 50-60 °C and 1000-2000 rad / mim for 3-8 hours. After stirring, filter and store it in a dark environment at 15-25 °C for standby.

[0042] Preferably, the filtration device used for filtration is composed of two-stage series connection of 0.22-micron and 1-micron filter elements. The two-stage filtration ensures to a certain extent the phenomenon of unstable inkjet caused by the filtration process parameters.

[0043] Compared with the prior art, the present invention has the following advantages:

[0044] 1. The prepolymer resin with a low addition amount but a high molecular weight is adopted, and at the same time, the dosage of the diluent monomer is coordinated. The viscosity range of the whole system is relatively low. The addition of the non-reactive resin enables the low viscosity not to affect shrinkage, and it can be stably jetted at low temperature with good forming effect. It has good jetting performance at 50 °C and above, especially stably jets at low temperature of 50-60 °C. The temperature is lower than that of competing products, reducing the damage to the whole machine equipment.

[0045] 2. The multifunctional monomer is combined with the non-reactive resin that does not react, and the shrinkage rate is low while maintaining the same stability and reaction rate of the system.

[0046] 3. The prepolymer and diluent monomer with low yellowing are adopted. At the same time, the monofunctional monomer is combined with the multifunctional monomer and the initiator with low molecular weight, resulting in low yellowing without affecting the reaction rate. It is suitable for models that require high transparency and for preparing color inks by adding dyes or pigments based on the transparent UV ink composition to print color models, with little influence on the color of the color system.

[0047] 4. The non-reactive resin component with good compatibility is adopted, so that a low shrinkage rate can be maintained even when multifunctional monomers are added, effectively reducing the shrinkage of the printing material. Specific embodiments

[0048] For the convenience of understanding the technical solution of the present invention, the following is a detailed description in combination with specific embodiments.

[0049] Example 1

[0050] (1) Weigh 15 parts of prepolymer resin GENOMER*4230, diluent monomers: 15 parts of monofunctional ACMO, 21.35 parts of monofunctional CTFA, 11 parts of monofunctional DEEA, 24 parts of multifunctional DCPDA, non-reactive resin LP 65 / 12: 12 parts by mass, photoinitiator TPO: 1.5 parts by mass, inhibitor p-methoxyphenol: 0.05 parts by mass, stabilizer GENORAD*20: 0.05 parts by mass, leveling agent BYK-377: 0.05 parts by mass. All of the above are in parts by mass. Stir well at 60°C and 1500 rad / min with a high-speed mixer for 4 hours.

[0051] (2) Filter the stirred ink through a filtering device composed of two stages in series with 0.22-μm and 1-μm filter elements, and then store the ink in a clean PP-sealed black plastic bottle and store it in a dark place at 15-25°C for standby.

[0052] (3) Thermal stability test

[0053] Take 200 g of the stored standby ink, store it in a metal heating cartridge dedicated to an inkjet 3D printer, and then place the cartridge in an oven at 60°C for 7 days. Compare the viscosity change after seven days. If the viscosity change is less than 3%, then proceed to the next step, the printing test.

[0054] (4) Conduct the printing test. Clean the cartridge and ink path of the inkjet 3D printer, add the filtered support material to the cartridge, pump the support material to fill the ink path, expel the air, adjust the negative pressure to -1.4 kPa, and conduct the ejection test. Only after the ejection is normal can printing be carried out;

[0055] After the ejection test is normal, set the printer light intensity at 8 w / cm2, the printing layer thickness at 10 μm, and the curing time of the curing lamp at 0.2 s;

[0056] After the above preparations are completed, start cyclic printing until the printing is completed;

[0057] After the printing is completed, clean the ink path and nozzle with 90% isopropyl alcohol. After cleaning, apply a moisturizer to the nozzle of the printer and store it in a dry environment to avoid moisture.

[0058] Example 2

[0059] Except that in step (1), 15 parts by mass of the prepolymer resin GENOMER*4247 is weighed, the other formula components and steps are the same as those in Example 1.

[0060] Example 3

[0061] Except that in step (1), 15 parts by mass of the prepolymer resin GENOMER*4212 is weighed, the other formula components and steps are the same as those in Example 1.

[0062] Example 4

[0063] Except that 15 parts of the prepolymer resin in the formulation are weighed as GENOMER*4297 in step (1), the remaining formulation components and steps are the same as those in Example 1.

[0064] Example 5

[0065] Except that 15 parts of the prepolymer resin in the formulation are weighed as GENOMER*4312 in step (1), the remaining formulation components and steps are the same as those in Example 1.

[0066] Example 6

[0067] Except that 15 parts of the prepolymer resin in the formulation are weighed as GENOMER*4425 in step (1), the remaining formulation components and steps are the same as those in Example 1.

[0068] Example 7

[0069] Except that 15 parts of the prepolymer resin in the formulation are weighed as GENOMER*4690 in step (1), the remaining formulation components and steps are the same as those in Example 1.

[0070] Example 8

[0071] Except that 15 parts of the prepolymer resin in the formulation are weighed as BR-952 in step (1), the remaining formulation components and steps are the same as those in Example 1.

[0072] Example 9

[0073] Except that 15 parts of the prepolymer resin in the formulation are weighed as BR-970 in step (1), the remaining formulation components and steps are the same as those in Example 1.

[0074] Example 10

[0075] Except that 15 parts of the prepolymer resin in the formulation are weighed as 6112-100 in step (1), the remaining formulation components and steps are the same as those in Example 1.

[0076] Example 11

[0077] Except that 15 parts of the prepolymer resin in the formulation are weighed as 6113 in step (1), the remaining formulation components and steps are the same as those in Example 1.

[0078] The formulation of step (1) in Examples 12-17 is shown in Table 4, and the remaining steps are the same as those in Example 1.

[0079] Table 4 Formulations of Examples 12-17

[0080]

[0081] The formulation of step (1) in Examples 18 - 23 is shown in Table 5, and the remaining steps are the same as those in Example 1.

[0082] Table 5 Formulation of Examples 18 - 23

[0083]

[0084]

[0085] The formulation of step (1) in Examples 24 - 29 is shown in Table 6, and the remaining steps are the same as those in Example 1.

[0086] Table 6 Formulation of Examples 24 - 29

[0087]

[0088] The formulation of step (1) in Examples 30 - 37 is shown in Table 7, and the remaining steps are the same as those in Example 1.

[0089] Table 7 Formulation of Examples 30 - 37

[0090]

[0091] The formulation of step (1) in Examples 40 - 53 is shown in Table 8, and the remaining steps are the same as those in Example 1.

[0092] Table 8 Formulation of Examples 40 - 53

[0093]

[0094]

[0095]

[0096] The formulation of Comparative Examples 1 - 10 is shown in Table 9, and the remaining steps are the same as those in Example 1.

[0097] Table 9 Formulation of Comparative Examples 1 - 10

[0098]

[0099] The ink performance of the transparent UV ink compositions of Examples 1 - 53 was tested, and the test contents are as follows:

[0100] 1. Viscosity: The viscosity of the ink was tested at 60 °C using a rheometer.

[0101] 2. Surface tension: The surface tension of the ink was measured at 60 °C using a dynamic surface tension measuring instrument.

[0102] 3. Thermal stability. The symbol markings for thermal stability are explained as follows:

[0103]

[0104] 4. Jet fluidity, evaluate the jetting performance of printing. The temperature for jetting performance test is 60°C. The symbol markings for jetting performance are explained as follows:

[0105]

[0106] 5. Printing accuracy, evaluate the printing accuracy of the printed model. The symbol markings for printing accuracy are explained as follows:

[0107]

[0108] 6. The symbol markings for yellowing performance are explained as follows:

[0109] Cured under a mercury lamp for 10 minutes, no obvious yellowing is observed by visual comparison under a white board. ◎

[0110] Cured under a mercury lamp for 10 minutes, slight yellowing is observed by visual comparison under a white board, and the yellowing fades within one day. ○

[0111] Cured under a mercury lamp for 10 minutes, slight or obvious yellowing is observed by visual comparison under a white board, and the yellowing does not fade significantly within 24 hours. △

[0112] Cured under a mercury lamp for 10 minutes, obvious yellowing is observed by visual comparison under a white board, and the yellowing does not fade. ╳

[0113] 7. Surface drying of the printing material, evaluate the surface drying of the printed model. The symbol markings are explained as follows:

[0114]

[0115] 8. Shrinkage rate of the printing material, the test method is as follows:

[0116] Use a solid-liquid density meter to measure the density (P1) of the liquid ink before printing and the density (P2) of the solid model after printing respectively. Calculate the shrinkage rate through the following formula:

[0117] Shrinkage rate (%) = (P2 - P1) / P1 * 100

[0118] The test results of Examples 1-17 are shown in Table 10:

[0119] Table 10 Performance Test Results of Examples 1-17

[0120]

[0121] Examples 1-11 tested the printing performance of different prepolymer materials. Only the types of prepolymers were different, and the other components were the same. Examples 1-7 compared prepolymer resins with the same prepolymer dosage but different viscosities and different functionalities. From the test results, it can be seen that when the viscosity of the prepolymer resin is lower than 10,000 mPas (Examples 4 and 6), the jetting performance is better, indicating that the viscosity and surface tension at this time are more suitable for jetting. However, the disadvantage is that the printing accuracy is low, and the shrinkage rate of the formed material is relatively large. When the viscosity of the prepolymer resin increases to 50,000-80,000 mPas (Examples 5 and 7), the material shrinkage rate decreases, but the accuracy is still not very good. At the same time, the jetting performance becomes very poor. When the viscosity of the prepolymer is in the range of 10,000-30,000 mPas (Examples 2 and 3), the jetting performance and shrinkage of the material are more appropriate. Examples 5-7 compared the effects of multi-functional monomers. It can be seen that the thermal stability shows a tendency to deteriorate with the increase in the functionality of the multi-functional monomer, probably because the probability of crosslinking increases. The prepolymers with a functionality of 2 have good thermal stability at 60 °C (Examples 1-4 and Examples 9-11). It should be noted here that in order to unify the standards when testing the thermal stability and jetting performance, all examples were measured at 60 °C, but this does not mean that their performance at 50 °C, 70 °C and other temperatures is poor. The applicant has tested that when the jetting performance / stability performance is better at 60 °C, the performance is also good when the temperature is appropriately increased or decreased (such as 50 °C, 70 °C). Examples 9-11 tested prepolymers from different manufacturers within the above viscosity range. When the structure and viscosity of the prepolymer are within the same range, the jetting performance, accuracy and shrinkage rate are all better. This shows that when the viscosity of the prepolymer is within this range, not only the viscosity and surface tension of the ink are more suitable, but also the reaction rate of the material is better, there is no obvious surface drying phenomenon, the shrinkage rate is relatively low, basically in the range of 6-7%, the forming effect is good, and the printing accuracy is good. In addition, prepolymers with methyl groups such as 4247 (Example 2) and 4297 (Example 4) are prone to surface drying of thick printing, indicating that prepolymers with methyl groups have a relatively low reaction rate and a relatively large amount of uncured components.

[0122] Examples 12-17 mainly tested the effects of the dosages of prepolymer resins with different viscosities. From the results, it can be seen that when the viscosity of the prepolymer resin is relatively low, such as in Examples 12 and 13, and Examples 14 and 15, within this viscosity range, although the jetting is better when the dosage is about 10%, the accuracy is poor and the shrinkage rate is large. When the dosage is increased to 20%, the shrinkage rate is lower, but the jetting performance is better. Only when the viscosity is in the range of 10,000-30,000 mPas and the dosage is in the range of 10-20% is there a more suitable dosage window.

[0123] The test results of Examples 18-33 are shown in Table 11:

[0124] Table 11 Performance Test Results of Examples 18 - 33

[0125]

[0126] Examples 18 - 33 tested the effects of different single-functional monomers, different amounts of multi-functional monomers, and the ratio of single-functional monomers to multi-functional monomers. Examples 18 - 23 compared several different multi-functional monomers and the effects of single-functional monomers. The feature is that when the single-functional monomer and the multi-functional monomer are proportionally combined within a suitable range, the overall effect is relatively good. Examples 19 - 26 compared the amounts of single-functional monomers and multi-functional monomers. By adjusting the ratio of single-functional monomers to multi-functional monomers, good synergistic effects can be achieved. While maintaining a good reaction rate and surface drying, good molding effects can also be obtained.

[0127] The test results of Examples 34 - 53 are shown in Table 12:

[0128] Table 12 Performance Test Results of Examples 34 - 53

[0129]

[0130]

[0131] Examples 34 - 53 tested the effects of several types of additives. Examples 34 - 37 tested the effects of three non-reactive resins. Fillers with larger molecular weights are not conducive to spraying, but have better shrinkage rates. Examples 38 - 41 tested the effects of different initiators and initiator dosages. In terms of initiator efficiency, photoinitiator 819 is the highest, but it is prone to yellowing. TPO and TPO-L are relatively more balanced. Examples 42 - 45 tested the effects of different inhibitors and inhibitor dosages. The inhibitor p-methoxyphenol has the lowest impact on yellowing and better light transmittance. Examples 46 - 49 tested the effects of different stabilizers. The stabilizer GENORAD*20 has better stabilizing effects and also improves the light transmittance, which is related to the presence of a small amount of whitening agent inside GENORAD*20. Examples 50 - 52 tested the effects of different leveling agents. The leveling agent BYK377 has better effects and there is no surface drying phenomenon.

[0132] By screening prepolymers and monomers with low yellowing, the monomers are combined with mono-functional and multi-functional monomers to maintain low yellowing and high light transmittance while increasing the reaction rate. In this case, to maintain a low shrinkage rate, a well-compatible acrylic resin filler is added to improve the problem of easy shrinkage caused by a large amount of multi-functional monomers. At the same time, a low-usage low-yellowing initiator is selected, which can not only maintain good surface drying but also prevent excessive yellowing and shrinkage. Through the control of prepolymers, mono-functional monomers, multi-functional monomers, well-compatible acrylic resin fillers, and the type and dosage of initiators, the ink prepared has a low viscosity at 60°C, can be stably ejected at a temperature of 60°C, and has good ejection performance; the forming effect is good, the surface drying is good, the transparency of the material is high, and the yellowing is good; the shrinkage rate of the material is low, and the shrinkage rate of the material after forming is 5%-7%.

[0133] The test results of Comparative Examples 1-10 are shown in Table 13 as follows:

[0134] Table 13 Performance Test Results of Comparative Examples 1-10

[0135]

[0136] Comparative Examples 1-2 compared with Example 9, and compared the experimental effects without prepolymers. When all are diluted monomers, the viscosity is low, and the ejection performance is not as good as expected, and there is an ink hanging phenomenon. Comparative Examples 3-4 and Comparative Examples 5-6 are the effects under the conditions of only mono-functional monomers and only bi-functional monomers respectively. When all the diluted monomers are mono-functional, the printing accuracy is relatively low, the reaction rate is slow, and there is a surface drying phenomenon of the material. When all the diluted monomers are bi-functional monomers, the thermal stability becomes poor, the printing accuracy becomes poor, and the shrinkage rate also increases. Comparative Examples 7-8 compared the situation without non-reactive resin. From the experimental results, the shrinkage rate of the material increases a lot, and the thermal stability also becomes poor, indicating that the addition of such components is beneficial to improving the thermal stability to a certain extent. Comparative Examples 9-10 compared the situation of high initiator dosage. When the initiator dosage increases, the yellowing of the material is very serious, and the printing accuracy also becomes poor.

[0137] The above is only the preferred implementation mode of the present invention. The protection scope of the present invention is subject to the scope defined by the claims. Several improvements and refinements made by those skilled in the art without departing from the spirit and scope of the present invention should also be regarded as the protection scope of the present invention.

Claims

1. A transparent UV ink composition suitable for inkjet 3D printing, based on 100 parts by mass, characterized in that Comprising the following components in parts by mass: 10 - 20 of prepolymer resin, and the prepolymer is an aliphatic acrylate resin with 2 functionality or more than 2 functionality; 66 - 77 parts of diluent monomer, the diluent monomer includes monofunctional monomer and polyfunctional monomer, and the mass ratio of the monofunctional monomer to the polyfunctional monomer is 1 - 3:1; 10 - 16 parts of non - reactive resin, 1 - 2 parts of photoinitiator, 0.01 - 0.1 part of inhibitor, and the inhibitor is a phenolic inhibitor.

2. The transparent UV ink composition applicable to inkjet 3D printing according to claim 1, characterized in that: The non - reactive resin is a polyacrylic acid resin; the photoinitiator is a free - radical type class I photoinitiator 819, TPO or TPO - L.

3. The transparent UV ink composition applicable to inkjet 3D printing according to claim 1, characterized in that: The monofunctional monomer is one or more of acryloylmorpholine, dimethylacrylamide, tetrahydrofurfuryl acrylate, trimethylolpropane formal acrylate, phenoxyethyl acrylate, 2 - ethoxyethyl acrylate, diethylacrylamide, isobornyl acrylate; the polyfunctional monomer is one or more of tricyclodecane dimethanol diacrylate, dipropylene glycol diacrylate, dipropylene glycol triacrylate, trimethylolpropane triacrylate, (3 - propoxy) glycerol triacrylate.

4. The transparent UV ink composition applicable to inkjet 3D printing according to claim 1, characterized in that: The prepolymer is a 2 - functionality aliphatic polyurethane acrylate resin, and the viscosity range of the prepolymer at 25℃ is 10000 - 20000 mPas.

5. The transparent UV ink composition applicable to inkjet 3D printing according to claim 1, characterized in that: The non - reactive resin is a polymer of methyl methacrylate and butyl methacrylate, a methyl methacrylate polymer or a methyl isobutyl methacrylate polymer with a relative molecular weight of 60000 - 80000.

6. The transparent UV ink composition applicable to inkjet 3D printing according to claim 1, characterized in that: The inhibitor is 2,4 - dimethyl - 6 - tert - butylphenol, p - methoxyphenol or piperidine alcohol oxide.

7. The transparent UV ink composition applicable to inkjet 3D printing according to claim 1, characterized in that: The transparent UV ink composition further comprises 0.01 - 0.1 part of stabilizer, and the stabilizer is one or two of aerobic inhibition type and anaerobic inhibition type.

8. The transparent UV ink composition applicable to inkjet 3D printing according to claim 1, characterized in that: The transparent UV ink composition further comprises 0.01 - 0.1 part of leveling agent, and the leveling agent is a polyacrylate leveling agent, an organosilicon resin leveling agent or a fluororesin surfactant leveling agent.

9. A method for preparing a transparent UV ink composition suitable for inkjet 3D printing according to any one of claims 1 to 7, characterized in that Comprising the following steps: Weigh the required prepolymer resin, diluent monomer, non - reactive resin, photoinitiator, inhibitor, stabilizer, leveling agent according to the ratio, then use a high - speed stirrer to stir at 50 - 60℃ and 1000 - 2000 rad / min for 3 - 8 hours, filter after stirring, and store in a dark environment at 15 - 25℃ for standby.

10. The preparation method according to claim 9, characterized in that: The filtering device used for filtration is composed of two - stage series connection of 0.22 - micron and 1 - micron filter elements.

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