阅读说明：本技术 一种3d打印光固化组合物及其制备方法 (3D printing photocuring composition and preparation method thereof ) 是由 程继业 臧圣彪 王洪武 任率祖 孙伟祖 于 2019-11-13 设计创作，主要内容包括：本发明涉及一种3D打印光固化组合物及其制备方法,该光固化组合物按原料重量百分比计包含40-70wt％的不饱和光固化树脂,20-50wt％的带有(甲基)丙烯酸酯基官能团的丙烯酸酯化合物,0.5-7wt％的光引发剂、0.1-3wt％助剂；其中不饱和光固化树脂由包含5-40wt％多异氰酸酯、50-85wt％含有活泼氢聚合物、5～15wt％羟基丙烯酰胺化合物的原料反应得到。本发明的3D打印光固化组合物具有黏度低、打印速度快、打印样品柔韧性好、打印尺寸精度高、样品表面质量佳等优点。(The invention relates to a 3D printing photocuring composition and a preparation method thereof, wherein the photocuring composition comprises 40-70 wt% of unsaturated photocuring resin, 20-50 wt% of acrylate compound with (methyl) acrylate functional group, 0.5-7 wt% of photoinitiator and 0.1-3 wt% of auxiliary agent according to the weight percentage of raw materials; the unsaturated light-cured resin is obtained by reacting raw materials comprising 5-40 wt% of polyisocyanate, 50-85 wt% of polymer containing active hydrogen and 5-15 wt% of hydroxy acrylamide compound. The 3D printing photocuring composition has the advantages of low viscosity, high printing speed, good flexibility of a printed sample, high printing size precision, good surface quality of the sample and the like.)

1. The 3D printing photocuring composition is characterized by comprising 40-70 wt%, preferably 50-65 wt%, of unsaturated photocuring resin, 20-50 wt%, preferably 30-45 wt%, of acrylate compound with (methyl) acrylate functional group, 0.5-7 wt%, preferably 1-5 wt%, of photoinitiator and 0.1-3 wt% of auxiliary agent; wherein the unsaturated light-cured resin is obtained by reacting raw materials comprising 5-40 wt%, preferably 10-30 wt%, more preferably 15-25 wt% of polyisocyanate, 50-85 wt%, preferably 60-80 wt% of active hydrogen-containing polymer and 5-15 wt%, preferably 5-10 wt% of hydroxy acrylamide compound, wherein the percentage is based on the total weight of the raw materials used for preparing the unsaturated light-cured resin.

2. The 3D printing photocurable composition according to claim 1, wherein the polyisocyanate is selected from one or two or more of aliphatic, alicyclic and aromatic polyisocyanates and derivatives of aliphatic, alicyclic and aromatic polyisocyanates, preferably one or two of tetramethylxylylene diisocyanate and isophorone diisocyanate in any ratio.

3. The 3D printing photocurable composition according to claim 1 or 2, wherein the active hydrogen-containing polymer is one or more of amino-terminated polypropylene glycol, hydroxyl-terminated polytetrahydrofuran and hydroxyl-terminated polypropylene glycol in any proportion; preferably, the mixture of the amino-terminated polypropylene glycol with the number average molecular weight of 1000-2000 and one or two of the hydroxyl-terminated polytetrahydrofuran and the hydroxyl-terminated polypropylene glycol in any proportion.

4. The 3D printing photocurable composition according to any of the claims 1-3 characterized in that the hydroxyacrylamide compound is one or a mixture of two of N-hydroxyethyl acrylamide, N-hydroxypropyl acrylamide, preferably N-hydroxyethyl acrylamide.

5. The 3D printing photocurable composition according to any one of claims 1-4, wherein the acrylate compound with (meth) acrylate-based functional group is a mixture of monofunctional (meth) acrylate and high-functional (meth) acrylate, wherein the monofunctional (meth) acrylate comprises one or two or more of hydroxyethyl (meth) acrylate, dicyclopentadiene (meth) acrylate, tetrahydrofuran (meth) acrylate, isobornyl (meth) acrylate, trimethylolpropane formal acrylate, acryloylmorpholine; the high functionality (meth) acrylate comprises one or two or more of cyclohexane dimethanol diacrylate, alkoxylated hexanediol diacrylate, ethoxylated bisphenol A di (meth) acrylate, polyethylene glycol di (meth) acrylate, tricyclodecane dimethanol diacrylate, trimethylolpropane tri (meth) acrylate, ethoxylated trimethylolpropane tri (meth) acrylate, propoxylated trimethylolpropane tri (meth) acrylate, ethoxylated pentaerythritol tetra (meth) acrylate, preferably one or more of dicyclopentadiene (meth) acrylate, trimethylolpropane formal acrylate, acryloyl morpholine, and one or more of polyethylene glycol di (meth) acrylate, tricyclodecane dimethanol diacrylate, and propoxylated trimethylolpropane tri (meth) acrylate in any proportion.

6. The 3D printing photocurable composition according to any one of claims 1-5, wherein the photoinitiator is 2-hydroxy-2-methyl-1-phenyl-1-propanone, 1-hydroxycyclohexyl phenyl ketone, 2-hydroxy-2-methyl-p-hydroxyethyl etherylphenyl-1-propanone, 2-benzyl-2-dimethylamino-1- (4-morpholinylphenyl) -1-butanone, 2,4, 6-trimethylbenzoyl-diphenylphosphorus oxide, 2,4, 6-trimethylbenzoyl-ethoxy-phenylphosphorus oxide, bis (2,4, 6-trimethylbenzoyl) -phenylphosphorus oxide, bis (2-hydroxy-2-methyl-p-hydroxy-2-hydroxyethyl etherylphenyl-1-propanone, At least one of isopropyl thianthrene, preferably 2,4, 6-trimethyl benzoyl-diphenyl phosphorus oxide, bis (2,4, 6-trimethyl benzoyl) -phenyl phosphorus oxide or mixture of two of them in any proportion.

7. The 3D printing photocuring composition according to any one of claims 1-6, wherein the auxiliary agent is one or a mixture of more of a defoaming agent, a polymerization inhibitor and an optional color paste in any proportion.

8. The method for preparing a 3D printing photocurable composition according to any of claims 1-7, characterized in that it comprises the following steps:

1) reacting polyisocyanate and a polymer containing active hydrogen for 1-5 hours at the temperature of 60-90 ℃ in the presence of a catalyst to obtain a prepolymer terminated by isocyanate groups;

2) reacting the prepolymer obtained in the step 1) with a hydroxyl acrylamide compound at 60-90 ℃ until the content of residual NCO reaches below 0.2%, so as to obtain unsaturated light-cured resin;

3) mixing the unsaturated light-cured resin obtained in the step 2) with an acrylate compound with a (meth) acrylate functional group, a photoinitiator and an auxiliary agent, stirring at a high speed in a stirrer, standing for defoaming after stirring uniformly, and obtaining the 3D printing light-cured composition.

9. The method according to claim 8, wherein the catalyst in step 1) is an organic bismuth-based catalyst.

10. The 3D printing photocurable composition according to any one of claims 1-7 or the 3D printing photocurable composition prepared by the preparation method of claim 8 or 9 is used for the preparation of 3D printing flexible materials.

Technical Field

The invention belongs to the field of photocuring 3D printing, and particularly relates to a 3D printing photocuring composition and a preparation method thereof, which are particularly suitable for 3D printing flexible materials.

Background

3D printing, also known as additive manufacturing, is the key direction of "china manufacturing 2025", and is widely used in more and more industries due to its technical advantages of simple and convenient molding. The photocuring 3D printing technology is the fast forming technology developed at the earliest, and is based on a digital file, three-dimensional models of objects are layered in one direction to obtain image information of the objects on each layer, a point light source is controlled by a computer to cure and form the liquid photocuring composition in a point-by-point scanning or surface light source direct projection mode, and a three-dimensional object is constructed by curing and forming layer by layer. The curing mode of the direct projection of the surface light source, namely the common Digital Light Processing (DLP) technology, has the advantages of higher forming speed, higher forming precision and better application prospect. Especially, the use of the LCD light source greatly reduces the price of the photocuring printer, and improves the application advantage of the photocuring 3D printing technology, but because the light source intensity is low, the curing time of each layer in the printing process is long, and the printing efficiency is reduced.

Unsaturated light-cured resin is an important component of light-cured compositions, and the reported method for preparing the rapid light-cured resin mainly improves the unsaturation degree of the resin, namely, improves the functionality degree of double bonds such as acrylate and the like contained in the resin. The photocuring resin with good soft and tough performance is generally monofunctional or bifunctional, the photocuring speed is not ideal generally, the general viscosity is high, a large amount of acrylate diluent monomers are required to be added for dilution in the use process, and a large amount of photoinitiator is required to be added for improving the initiation efficiency, which are not beneficial to improving the performance of the material. Therefore, the photocurable resin prepared by the method has the defects of poor chemical strength and low surface quality when being used for flexible 3D printing of the photocurable composition, and the printing process requires longer exposure time and has lower printing success rate and printing efficiency.

The invention content is as follows:

in order to solve the technical problems, the invention synthesizes an unsaturated light-cured resin which has high mechanical strength and low viscosity and can be rapidly cured, develops a light-cured composition which can be used for light-cured 3D printing based on the synthesized resin, can effectively improve the printing efficiency when used for 3D printing flexible materials, and ensures that printed products have ideal surface quality and mechanical strength.

Another object of the present invention is to provide a method for preparing the above 3D printing photocurable composition.

In order to achieve the purpose, the invention adopts the following technical scheme:

the 3D printing photocuring composition comprises, by weight, 40-70% of unsaturated photocuring resin, 20-50% of acrylate compound with (methyl) acrylate functional groups, 0.5-7% of photoinitiator and 0.1-3% of auxiliary agent. The unsaturated light-cured resin is obtained by reacting raw materials comprising 5-40 wt% of polyisocyanate, 50-85 wt% of polymer containing active hydrogen and 5-15 wt% of hydroxyacrylamide compound, wherein the percentage is based on the total weight of the raw materials used for preparing the unsaturated light-cured resin.

The 3D printing light-cured composition in the invention is prepared from one or two or more of aliphatic, alicyclic and aromatic polyisocyanates and derivatives of aliphatic, alicyclic and aromatic polyisocyanates, such as 1, 6-Hexamethylene Diisocyanate (HDI), dicyclohexylmethane diisocyanate (H)₁₂MDI), isophorone diisocyanate (IPDI), Toluene Diisocyanate (TDI), tetramethylxylylene diisocyanate, (TMXDI), HDI biuret, HDI trimer, IPDI trimer, and the like. The IPDI and the TXMDI have better structure selectivity in the synthetic process of the light-cured resin, the reaction process is easy to control, and the light-cured resin prepared by the IPDI and the TXMDI has lower viscosity and better mechanical property. Therefore, one or a mixture of TMXDI and IPDI in any proportion is preferred. The content of polyisocyanate is 5 to 40 wt%, preferably 10 to 30 wt%, more preferably 15 to 25 wt% based on the weight percentage of the raw material of the unsaturated light-curing resin.

The 3D printing photocuring composition is a mixture of one or more of amino-terminated polypropylene glycol, hydroxyl-terminated polytetrahydrofuran and hydroxyl-terminated polypropylene glycol in any proportion, wherein the polymer containing active hydrogen is the mixture; preferably, the mixture of the amino-terminated polypropylene glycol with the number average molecular weight of 1000-2000 and one or two of the hydroxyl-terminated polytetrahydrofuran and the hydroxyl-terminated polypropylene glycol in any proportion. The active hydrogen-containing polymer accounts for 50-85 wt%, preferably 60-80 wt% of the unsaturated light-cured resin according to the weight percentage of the raw materials.

In the 3D printing photocuring composition, the hydroxy acrylamide compound is one or a mixture of two of N-hydroxyethyl acrylamide and N-hydroxypropyl acrylamide, and N-hydroxyethyl acrylamide is preferred. The hydroxyl acrylamide compound C accounts for 5-15 wt%, preferably 5-10 wt% of the unsaturated light-cured resin according to the weight percentage of the raw materials.

Generally speaking, unsaturated photocuring resins prepared by using hydroxyl-terminated polyether have low viscosity, easy reaction control and good cured sample flexibility, but generally have poor mechanical strength. The amino-terminated polypropylene glycol is used for preparing unsaturated light-cured resin, so that the mechanical strength of the product can be effectively improved, but the reaction is difficult to control, and the viscosity of the product is high. The two components are compounded for use, so that the advantages of the two components can be effectively combined, the resin is ensured to have lower viscosity, and the product after the resin is cured has good mechanical strength. And the hydroxy acrylamide compound is used for replacing the commonly used hydroxy acrylic ester, so that the resin has higher photocuring activity even if only containing lower double bond density, and the lower double bond density is also beneficial to improving the flexibility of the product of the photocuring composition after being cured.

The 3D printing photocuring composition provided by the invention is a mixture of monofunctional (meth) acrylate and high-functionality (meth) acrylate, wherein the monofunctional (meth) acrylate comprises one or two or more of hydroxyethyl (meth) acrylate, dicyclopentadiene (meth) acrylate, tetrahydrofuran (meth) acrylate, isobornyl (meth) acrylate, trimethylolpropane formal acrylate and acryloyl morpholine. The high functionality (meth) acrylate comprises one or two or more of cyclohexane dimethanol diacrylate, alkoxylated hexanediol diacrylate, ethoxylated bisphenol A di (meth) acrylate, polyethylene glycol di (meth) acrylate, tricyclodecane dimethanol diacrylate, trimethylolpropane tri (meth) acrylate, ethoxylated trimethylolpropane tri (meth) acrylate, propoxylated trimethylolpropane tri (meth) acrylate, ethoxylated pentaerythritol tetra (meth) acrylate, preferably mixtures of dicyclopentadiene (meth) acrylate, trimethylolpropane formal acrylate, acryloyl morpholine with one or more of polyethylene glycol di (meth) acrylate, tricyclodecane dimethanol diacrylate, propoxylated trimethylolpropane tri (meth) acrylate in any proportion, the acrylate compound accounts for 20-50 wt%, preferably 30-45 wt% of the total weight of the raw materials of the 3D printing photocuring composition. The acrylate compound having a (meth) acrylate-based functional group has limitations on its single-type performance, such as curing speed, volume shrinkage, hardness, etc., and therefore, it is necessary to use it in combination.

The 3D printing photocurable composition of the invention is prepared by photo-initiation of at least one of 2-hydroxy-2-methyl-1-phenyl-1-acetone, 1-hydroxycyclohexyl phenyl ketone, 2-hydroxy-2-methyl-p-hydroxyethyl etherphenyl-1-acetone, 2-benzyl-2-dimethylamino-1- (4-morpholinylphenyl) -1-butanone, 2,4, 6-trimethylbenzoyl-diphenyl phosphorus oxide, 2,4, 6-trimethylbenzoyl-ethoxy-phenyl phosphorus oxide, bis (2,4, 6-trimethylbenzoyl) -phenyl phosphorus oxide, isopropyl thia-nthrene, preferably 2,4, 6-trimethylbenzoyl-diphenyl phosphorus oxide, One or two of bis (2,4, 6-trimethylbenzoyl) -phenyl phosphorus oxide in any proportion. The photoinitiator accounts for 0.5-7 wt%, preferably 1-5 wt% of the total weight of the raw materials of the 3D printing photocuring composition.

The auxiliary agent of the 3D printing photocuring composition is one or a mixture of a defoaming agent, a polymerization inhibitor and an optional color paste in any proportion, and accounts for 0.1-3 wt% of the total weight of the 3D printing photocuring composition. The polymerization inhibitor can be hydroquinone, hydroxyanisole, 2, 6-di-tert-butyl-4-methylphenol, tetramethylpiperidine oxynitride and the like, and is preferably p-hydroxyanisole.

The preparation method of the 3D printing photocuring composition comprises the following steps:

1) reacting polyisocyanate and a polymer containing active hydrogen for 1-5 hours at the temperature of 60-90 ℃ in the presence of a catalyst to obtain a prepolymer terminated by isocyanate groups;

2) reacting the prepolymer obtained in the step 1) with a hydroxyl acrylamide compound at 60-90 ℃ until the content of residual NCO reaches below 0.2%, so as to obtain the unsaturated light-cured resin.

3) Stirring the unsaturated photocuring resin obtained in the step 1) with an acrylate compound with a (meth) acrylate functional group, a photoinitiator, a polymerization inhibitor, an optional color paste and a defoaming agent at a high speed in a stirrer at a temperature of 30-50 ℃ for 30-60min at a stirring speed of 400-500r/min, uniformly stirring, and standing for defoaming to obtain the 3D printing photocuring composition.

In the invention, the catalyst for the unsaturated light-cured resin synthesis reaction is an organic bismuth catalyst, and the dosage of the organic bismuth catalyst is 0.01-1.0 wt% of the total weight of the raw materials.

The 3D printing photocuring composition can be used for 3D printing consumables, and has the advantages of low viscosity, high printing speed, good flexibility of a printed sample, high printing size precision, good surface quality of the sample and the like through the adjustment of the contents of unsaturated photocuring resin, acrylate diluent monomer, photoinitiator and auxiliary agent.

The specific implementation mode is as follows:

the principles and features of this invention are described below in conjunction with examples which are intended to illustrate the invention and are not intended to limit the scope of the invention.

In the following examples and comparative examples, the sources of the main raw materials are as follows:

tetramethylxylylene diisocyanate (TMXDI): cyanogen special chemical industry and industrial products.

Isophorone diisocyanate (IPDI): wanhua chemical products and industrial products.

Hydroxyl terminated polytetrahydrofuran (PTMEG number average molecular weight 2000): shanxi, three-dimensional, industrial.

Hydroxyl terminated polypropylene glycol (PPG-1000, PPG-2000): wanhua chemical products and industrial products.

Amino terminated polypropylene glycol D2000(D2000, number average molecular weight 2000): hensman, industrial.

N-hydroxyethyl acrylamide: shanghai Polyrui, Industrial product.

Acryloyl morpholine: double bond chemical Limited, Industrial products.

Polyethylene glycol diacrylate: double bond chemical Limited, Industrial products.

Trimethylolpropane formal acrylate: sartomer (guangzhou) chemical limited, industrial.

Tricyclodecane dimethanol diacrylate: sartomer (guangzhou) chemical limited, industrial.

Trimethylolpropane propoxylate triacrylate: sartomer (guangzhou) chemical limited, industrial.

2,4, 6-trimethylbenzoyl-diphenylphosphinic oxide: double bond chemical Limited, Industrial products.

Bis (2,4, 6-trimethylbenzoyl) -phenylphosphoric oxide: double bond chemical Limited, Industrial products.

P-hydroxyanisole: alatin, reagent grade.

Defoaming agent: BYK 1790, Industrial product.

Example 1: preparation of unsaturated light-curing resin

77.2g of tetramethylxylylene diisocyanate (TMXDI), 290g of amino terminated polyether (D2000), 105g of hydroxyl terminated polypropylene glycol (PPG-2000) and 0.3g of bismuth neodecanoate as a catalyst were put into a reaction flask equipped with a stirring device and a temperature control device, an inert protective gas was introduced, the reaction was carried out at 60 ℃ for 1.5 hours, the NCO content of the prepolymer was 2.21% by weight as determined by n-butylamine titration, 27.5g of N-hydroxyethyl acrylamide was added, and the reaction was carried out at 60 ℃ for 4 hours, whereby the residual NCO content was 0.12% by weight as determined. The reaction was stopped to obtain an unsaturated photocurable resin.

Example 2: preparation of unsaturated light-curing resin

89.77g of tetramethylxylylene diisocyanate (TMXDI), 184g of amino terminated polyether (D2000), 184g of hydroxyl terminated polypropylene glycol (PPG-2000) and 0.3g of bismuth neodecanoate serving as a catalyst were put into a reaction flask equipped with a stirring device and a temperature control device, an inert protective gas was introduced, the reaction was carried out at 80 ℃ for 1 hour, the NCO content of the prepolymer was 3.51% by weight as measured by n-butylamine titration, 43g of N-hydroxyethyl acrylamide was added, the reaction was carried out at 80 ℃ for 2.5 hours, and the residual NCO content was 0.08% by weight as measured. The reaction was stopped to obtain an unsaturated photocurable resin.

Example 3: preparation of unsaturated light-curing resin

115g of isophorone diisocyanate (IPDI), 230g of amino terminated polyether (D2000), 230g of hydroxyl terminated polypropylene glycol (PPG-1000) and 0.3g of catalyst bismuth neodecanoate are added into a reaction bottle provided with a stirring device and a temperature control device, inert protective gas is introduced, the reaction is carried out for 1 hour at 70 ℃, the NCO content of the prepolymer is 2.53 wt% measured by n-butylamine titration method, 40g N-hydroxyethyl acrylamide is added, the reaction is carried out for 3 hours at 70 ℃, and the residual NCO content is 0.10 wt% measured. The reaction was stopped to obtain an unsaturated photocurable resin.

Example 4: preparation of unsaturated light-curing resin

131.6g of tetramethylxylylene diisocyanate (TMXDI), 308g of amino-terminated polyether (D2000), 308g of hydroxyl-terminated polytetrahydrofuran (PTMEG-2000) and 0.3g of bismuth neodecanoate as a catalyst were put into a reaction flask equipped with a stirring device and a temperature control device, an inert protective gas was introduced, the reaction was carried out at 80 ℃ for 1 hour, the NCO content of the prepolymer was 3.31% by weight as determined by n-butylamine titration, 52g of N-hydroxyethyl acrylamide was added, the reaction was carried out at 80 ℃ for 3 hours, and the residual NCO content was 0.10% by weight as determined. The reaction was stopped to obtain an unsaturated photocurable resin.

Example 5: preparation of unsaturated light-curing resin

74.5g of isophorone diisocyanate (IPDI), 284g of amine terminated polyether (D2000), 110g of hydroxyl terminated polypropylene glycol (PPG-2000) and 0.3g of catalyst bismuth neodecanoate are added into a reaction bottle provided with a stirring device and a temperature control device, inert protective gas is introduced, the reaction is carried out for 1 hour at 80 ℃, the NCO content of the prepolymer is 2.60 wt% measured by n-butylamine titration method, 32g of N-hydroxyethyl acrylamide is added, the reaction is carried out for 3 hours at 80 ℃, and the residual NCO content is 0.06 wt% measured. The reaction was stopped to obtain an unsaturated photocurable resin.

Example 6: preparation of unsaturated light-curing resin

114.5g of tetramethylxylylene diisocyanate (TMXDI), 130g of amino terminated polyether (D2000), 230g of hydroxyl terminated polypropylene glycol (PPG-2000) and 0.3g of bismuth neodecanoate as a catalyst were put into a reaction flask equipped with a stirring device and a temperature control device, an inert protective gas was introduced, the reaction was carried out at 80 ℃ for 1 hour, the NCO content of the prepolymer was 2.03% by weight as measured by n-butylamine titration, 25g of N-hydroxyethylacrylamide was added, the reaction was carried out at 80 ℃ for 3 hours, and the residual NCO content was 0.04% by weight as measured. The reaction was stopped to obtain an unsaturated photocurable resin.

Example 7: preparation of 3D printing photocurable composition

Adding 55g of the unsaturated light-cured resin synthesized in the example 1, 25g of acryloyl morpholine, 20g of polyethylene glycol diacrylate, 5g of 2,4, 6-trimethyl benzoyl-diphenyl phosphorus oxide, 0.05g of p-hydroxyanisole and 0.7g of defoaming agent BYK-1790 into a stirrer, stirring at the rotation speed of 500r/min at 30 ℃ for 30min, standing for defoaming after uniform stirring, and obtaining the 3D printing light-cured composition.

Example 8: preparation of 3D printing photocurable composition

60g of the unsaturated light-cured resin synthesized in the example 2, 30g of trimethylolpropane formal acrylate, 15g of tricyclodecane dimethanol diacrylate, 3g of bis (2,4, 6-trimethylbenzoyl) -phenyl phosphorus oxide, 0.05g of p-hydroxyanisole and 0.7g of defoaming agent BYK-1790 are added into a stirrer, stirred for 30min at the rotating speed of 500r/min at the temperature of 30 ℃, and after the mixture is uniformly stirred, the mixture is kept stand for defoaming to obtain the 3D printing light-cured composition.

Example 9: preparation of 3D printing photocurable composition

55g of the unsaturated light-cured resin synthesized in example 3, 20g of acryloyl morpholine, 25g of tricyclodecane dimethanol diacrylate, 2g of bis (2,4, 6-trimethylbenzoyl) -phenyl phosphorus oxide, 1g of 2,4, 6-trimethylbenzoyl-diphenyl phosphorus oxide, 0.05g of p-hydroxyanisole and 0.7g of a defoaming agent BYK-1790 are added into a stirrer, stirred at the rotation speed of 500r/min at 30 ℃ for 30min, and kept stand for defoaming after being stirred uniformly to obtain the 3D printing light-cured composition.

Example 10: preparation of 3D printing photocurable composition

65g of the unsaturated photocuring resin synthesized in example 4, 25g of acryloyl morpholine, 10g of propoxyprimethylolpropane triacrylate, 2g of bis (2,4, 6-trimethylbenzoyl) -phenylphosphoric oxide, 2g of 2,4, 6-trimethylbenzoyl-diphenylphosphoric oxide, 0.05g of p-hydroxyanisole and 0.7g of defoamer BYK-1790 are added into a stirrer, stirred at the rotation speed of 500r/min at 30 ℃ for 30min, and after stirring uniformly, the mixture is kept stand for defoaming to obtain the 3D printing photocuring composition.

Example 11: preparation of 3D printing photocurable composition

54g of the unsaturated light-cured resin synthesized in the example 5, 25g of acryloyl morpholine, 20g of tricyclodecane dimethanol diacrylate, 4g of 2,4, 6-trimethyl benzoyl-diphenyl phosphorus oxide, 0.05g of p-hydroxyanisole and 0.7g of defoaming agent BYK-1790 are added into a stirrer, stirred at the temperature of 30 ℃ and the rotating speed of 500r/min for 30min, and after the mixture is uniformly stirred, the mixture is kept stand for defoaming, so that the 3D printing light-cured composition is obtained.

Example 12: preparation of 3D printing photocurable composition

65g of the unsaturated light-curing resin synthesized in example 6, 15g of trimethylolpropane formal acrylate, 20g of tricyclodecane dimethanol diacrylate, 4g of 2,4, 6-trimethylbenzoyl-diphenyl phosphorus oxide, 0.05g of p-hydroxyanisole and 0.7g of defoaming agent BYK-1790 are added into a stirrer, stirred for 30min at the rotating speed of 500r/min at the temperature of 30 ℃, and after being uniformly stirred, the mixture is kept stand for defoaming, so that the 3D printing light-curing composition is obtained.

Comparative example 1:

74.5g of isophorone diisocyanate (IPDI), 384g of poly neopentyl glycol adipate diol (PNA-2000) and 0.3g of catalyst bismuth neodecanoate are added into a reaction bottle provided with a stirring device and a temperature control device, inert protective gas is introduced, the reaction is carried out for 1 hour at 80 ℃, the NCO content of the prepolymer is 2.55 wt% measured by n-butylamine titration method, 32g of hydroxyethyl acrylate is added, the reaction is carried out for 3 hours at 80 ℃, and the residual NCO content is 0.15 wt% measured. The reaction was stopped to obtain an unsaturated photocurable resin. Adding 55g of the synthesized unsaturated light-cured resin, 25g of acryloyl morpholine, 20g of polyethylene glycol diacrylate, 5g of 2,4, 6-trimethyl benzoyl-diphenyl phosphorus oxide, 0.05g of p-hydroxyanisole and 0.7g of defoaming agent BYK-1790 into a stirrer, stirring at the rotation speed of 500r/min at 30 ℃ for 30min, standing for defoaming after uniform stirring, and obtaining the 3D printing light-cured composition.

The 3D printing light-cured compositions prepared in examples 8 to 12 and comparative examples were printed on test samples by an L120 type LCD light-cured printer of Beijing Dayu three-dimensional company, and the viscosity of the 3D printing light-cured compositions, the exposure time required for each layer in the printing process, and the hardness and surface quality of the printed products were tested. The product bending test method is to print a cuboid product of 10cm x 1mm, bend the product by 180 degrees, and test the bending times required by the product bending fracture (generally, a flexible material refers to soft and tough, the soft is reflected by a hardness test, and the tough can be indicated by a bending test). The properties of the photocurable composition prepared in the examples and the printed sample are shown in Table 1. As can be seen from table 1, the 3D printing photocurable composition prepared by the present invention has a low viscosity, a short curing time per layer, and a high surface quality.

TABLE 1 Performance indices of photocurable compositions and printed samples