A dicyclohexylmethane diisocyanate composition and its application in 3D printing field

Abstract

The present invention relates to a dicyclohexylmethane diisocyanate composition and its application in the field of 3D printing, wherein the dicyclohexylmethane diamine diisocyanate contains 2,4'-dicyclohexylmethane diisocyanate (2,4'-HMDI) and 4,4'-dicyclohexylmethane diisocyanate (4,4'-HMDI) at the same time; wherein the content of the 2,4'-dicyclohexylmethane diisocyanate accounts for 2-20wt%; and the content of the trans-, trans-'-dicyclohexylmethane diisocyanate in the 4,4'-dicyclohexylmethane diisocyanate is 5-30%. The photocurable composition prepared by using the HMDI provided by the present invention has the advantages of low viscosity, shorter single-layer curing time, high printing efficiency, good flexibility of printed samples, etc.

Description

Technical Field

[0001] The present invention belongs to the field of photocuring 3D printing, and specifically relates to a 3D printing photocuring composition, which is especially suitable for 3D printing flexible materials. Background Art

[0002] 3D printing, also known as additive manufacturing, has been widely used in more and more industries due to its simple and convenient molding technology advantages. Photocuring 3D printing technology is the earliest developed rapid prototyping technology. It is based on digital files. By layering the three-dimensional model of the object in one direction, the image information of each layer of the object is obtained, and then the liquid photocurable composition is cured and formed by computer-controlled point light sources in the form of point-by-point scanning or direct projection of surface light sources, and three-dimensional objects are constructed by layer-by-layer curing. Among them, the curing method of direct projection of surface light sources, that is, the common digital light processing (DLP) technology, has a faster molding speed, higher molding accuracy, and better application prospects. In particular, the use of LCD light sources has greatly reduced the price of photocuring printers and increased the application advantages of photocuring 3D printing technology. However, due to its low light source intensity, the curing time of each layer during the printing process is longer, which reduces the printing efficiency.

[0003] Unsaturated photocurable resin is an important component of photocurable composition. The reported method for preparing fast photocurable resin is mainly to increase the unsaturation of the resin, that is, to increase the functionality of double bonds such as acrylate contained in the resin. The photocurable unsaturated resin prepared by this method usually has a higher hardness and a faster reaction speed, but its high crosslinking density also leads to poor flexibility. The product is usually brittle and is not suitable for preparing flexible materials. Photocurable resins with good soft and tough properties are usually monofunctional or difunctional, and their photocuring speed is usually not ideal, and the viscosity is generally high. During use, a large amount of acrylate dilution monomers need to be added for dilution, and a large amount of photoinitiator needs to be added to improve the initiation efficiency, all of which are not conducive to improving the performance of the material. Therefore, the photocurable resin prepared by the above method usually has the disadvantages of poor mechanical strength and poor yellowing resistance when used in flexible 3D printing photocurable compositions.

[0004] Patent CN112876615A provides a 3D printing photocurable composition. Although the composition has the characteristics of high mechanical strength, low viscosity and fast curing speed, according to its implementation effect, the single-layer photocuring time is still more than 3s, while in the current public technology, the single-layer photocuring time is generally more than 4s. This is mainly because when using traditional photocurable compositions, in order to ensure the flowability of the material when entering the printer, relatively non-crystallizable materials are selected in the material composition for the synthesis of the photocurable composition, which requires sufficient photocuring time to ensure the complete curing of the material. Although the single-layer photocuring time of 3-4s is already at a relatively high level, in the formal large-scale production process, the shorter the time required for a single 3D printed product, the higher the efficiency of the machine per unit time and the higher the production capacity. Therefore, reducing the single-layer photocuring time has a great effect on improving production efficiency. Summary of the invention

[0005] In view of the above problems existing in the prior art, the purpose of the present invention is to develop a dicyclohexylmethane diisocyanate composition, which is applied to a 3D printing photocurable composition, having a shorter single-layer photocuring time, excellent mechanical strength and yellowing resistance.

[0006] To achieve the above object, the present invention adopts the following technical solution:

[0007] The present invention provides a dicyclohexylmethane dicyanate (HMDI) composition on one hand, wherein the dicyclohexylmethane dicyanate composition contains isomers 2,4'-dicyclohexylmethane diisocyanate (2,4'-HMDI) and 4,4'-dicyclohexylmethane diisocyanate (4,4'-HMDI) at the same time; wherein the content of the 2,4'-dicyclohexylmethane diisocyanate is 2-20wt%, preferably 4-15wt%, and more preferably 6-12wt%;

[0008] The 4,4'-dicyclohexylmethane diisocyanate includes three isomers of cis, cis'-dicyclohexylmethane diisocyanate (c, c'-HMDI), cis, trans'-dicyclohexylmethane diisocyanate (c, t'-HMDI), and trans, trans'-dicyclohexylmethane diisocyanate (t, t'-HMDI). The mass of the dicyclohexylmethane diisocyanate composition is 100%, wherein the content of trans, trans'-dicyclohexylmethane diisocyanate is 5-30%, preferably 7-25%, and more preferably 8-25%. In addition, the present invention has no special requirements for the content of the two isomers of cis, cis'-dicyclohexylmethane diisocyanate and cis, trans'-dicyclohexylmethane diisocyanate in the composition.

[0009] The preparation method of the dicyclohexylmethane dicyanate composition of the present invention has no specific requirements, and the dicyclohexylmethane dicyanate composition of the composition can be obtained by any achievable method in the prior art, such as the following method can be preferably used:

[0010] Method 1: Prepare the dicyclohexylmethane dicyanate composition of the present invention by regulating the isomer content in the raw materials. The isomers in the HMDI composition are derived from the raw material dicyclohexylmethane diamine (HMDA), or even from the raw material diphenylmethane diamine (MDA) of HMDA. The preparation of the HMDI composition of the present invention can be achieved by regulating the 2,4'-MDA content in MDA and the t,t'-HMDA content in HMDA; the specific operation can refer to the methods disclosed in the prior art, such as the method for regulating 2,4'-HMDA in HMDA disclosed in patent CN101429139A, and the method for regulating t,t'-HMDA is also mentioned in patent CN103265438A.

[0011] Method 2: Existing dicyclohexylmethane dicyanate products with different isomer compositions are used to prepare the dicyclohexylmethane dicyanate composition of the present invention through a separation process. In the subsequent separation process of preparing the HMDI product from HMDA, the content of different isomers in the HMDI composition is adjusted through different separation processes such as crystallization and distillation.

[0012] Method 3: preparing the dicyclohexylmethane dicyanate composition of the present invention by mixing different isomers, for example, by adding corresponding isomers to a conventional HMDI composition.

[0013] The above three methods can be used in combination or individually, and the present invention does not limit the method for obtaining the HMDI composition.

[0014] The content of related isomers in the dicyclohexylmethane diisocyanate composition described in the present invention can be analyzed by gas chromatography. The present invention has no specific requirements. For example, the method used in some specific examples is: the sample is dissolved in a solvent (preferably dichloromethane) and then analyzed by gas chromatography, and detected by a hydrogen ion flame detector (FID). The purity of HMDI is quantitatively calculated by area normalization method.

[0015] The dicyclohexylmethane diisocyanate composition of the present invention can be used in the field of 3D printing, and is suitable for preparing 3D printing photocurable materials, and is particularly suitable for preparing 3D printing flexible materials.

[0016] The isomer composition of HMDI product compositions currently on the market is mainly 4,4'-HMDI, and the content is basically required to be above 99.5%. There is no special requirement for the content of 2,4'-HMDI. For example, Wanhua Chemical Enterprise Standard Q / 0600YPU028-2016 "4,4'-Dicyclohexylmethane Diisocyanate" discloses three dicyclohexylmethane diisocyanate compositions, Wannate HMDI, Wannate H1210, and Wannate H1200. The content of 2,4'-HMDI is not clearly stated in their compositions, and Wannate H1200 also clearly mentions that the content of 4,4'-HMDI is above 99.5%. In addition, the existing products do not further limit the proportion of the three isomers c,c'-HMDI, c,t'-HMDI and t,t'-HMDI contained in 4,4'-HMDI. The above three products also do not mention any specific requirements for the respective contents of cis and trans isomers in 4,4'-HMDI.

[0017] The inventors found in their research on 3D printing materials that, since 2,4'-HMDI has a certain asymmetry compared with 4,4'-HMDI, adding a certain amount of 2,4'-HMDI to the HMDI-based photocurable resin raw material for flexible 3D printing compositions can effectively improve the flexibility of 3D printed products. At the same time, the content of 2,4'-HMDI also needs to be controlled within the scope of the present invention. When the content of 2,4'-HMDI is too high, it will affect the mechanical properties of 3D printed products. The inventors also found that t,t' -HMDI has higher symmetry than other isomers and has better crystallization performance. If the proportion of t,t'-HMDI in the HMDI-based photocurable resin raw material used for flexible 3D printing composition is controlled within a certain range, it can effectively improve the exposure time required for the 3D printing process and greatly improve the 3D printing efficiency. However, the content of t,t'-HMDI also needs to be strictly controlled. When the content of t,t'-HMDI exceeds the specified range of the present invention, it will not only cause the HMDI composition itself to crystallize, but also make the viscosity of the prepared photocurable composition high. The photocurable composition made of HMDI that meets the above-mentioned isomer composition requirements can have the advantages of low viscosity, short single-layer curing time, fast printing speed, high efficiency, and good flexibility of printed samples.

[0018] Another aspect of the present invention further provides a 3D printing photocurable composition, wherein the total mass of the raw materials of the 3D printing photocurable composition is 100%, and the raw material composition thereof comprises:

[0019] 35-75wt% of unsaturated photocurable resin, preferably 45-65%, wherein the unsaturated photocurable resin is prepared from the dicyclohexylmethane dicyanate composition of the present invention;

[0020] 18-54 wt % of an acrylate compound having a (meth)acrylate functional group, preferably 35-50 wt %;

[0021] Photoinitiator 0.5-10wt%, preferably 1-4.5wt%;

[0022] Additives 0.1~3wt%.

[0023] In the 3D printing photocurable composition of the present invention, the unsaturated photocurable resin is prepared by reacting the dicyclohexylmethane diisocyanate composition of the present invention, the active hydrogen-containing polymer, and the acrylamide compound as raw materials; preferably, based on the total mass of the raw materials for preparing the unsaturated photocurable resin as 100%, the raw material composition includes:

[0024] Dicyclohexylmethane diisocyanate composition 7-45%, preferably 12-30%, more preferably 15-25%;

[0025] Contains 45-80% active hydrogen polymer, preferably 55-75%;

[0026] The acrylamide compound is 5 to 15%, preferably 5 to 10%.

[0027] Preferably, the active hydrogen-containing polymer is selected from any one of amino-terminated polypropylene glycol, hydroxyl-terminated polytetrahydrofuran, hydroxyl-terminated polypropylene glycol, polyethylene glycol, polypropylene glycol, polytetrahydrofuran diol, polycaprolactone diol, polylactic acid diol, polyethylene adipate diol, polybutylene adipate diol, polybutadiene diol, 2,2-dihydroxymethylpropionic acid, and N-methyldiethanolamine, or a combination of at least two thereof; preferably amino-terminated polypropylene glycol and / or hydroxyl-terminated polypropylene glycol.

[0028] Preferably, the acrylamide compound is any one of acrylamide, N-isopropyl acrylamide, acrylic acid, methacrylic acid, hydroxyethyl acrylate, hydroxyethyl methacrylate, N-vinyl pyrrolidone, N-hydroxyethyl acrylamide, and N-hydroxypropyl acrylamide, or a combination of at least two thereof, preferably N-hydroxyethyl acrylamide.

[0029] In the 3D printing photocurable composition of the present invention, the acrylate compound with a (meth)acrylate functional group is a mixture of a monofunctional (meth)acrylate and a high-functionality (meth)acrylate, wherein the monofunctional (meth)acrylate comprises any one or a combination of at least two of hydroxyethyl (meth)acrylate, dicyclopentadiene (meth)acrylate, tetrahydrofuran (meth)acrylate, isobornyl (meth)acrylate, trimethylolpropane formal acrylate, and acryloyl morpholine, preferably acryloyl morpholine and / or trimethylolpropane formal acrylate; The high-functionality (meth)acrylate comprises any one or a combination of at least two of cyclohexanedimethanol 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, and ethoxylated pentaerythritol tetra(meth)acrylate, preferably polyethylene glycol di(meth)acrylate and / or tricyclodecane dimethanol diacrylate.

[0030] In the 3D printing photocurable composition of the present invention, the photoinitiator is 2-hydroxy-2-methyl-1-phenyl-1-propanone, 1-hydroxycyclohexyl phenyl ketone, 2-hydroxy-2-methyl-p-hydroxyethyl ether phenyl-1-propanone, 2-benzyl-2-dimethylamino-1-(4-morpholinophenyl)-1-butanone, 2,4,6-trimethylbenzoyl-diphenyl phosphine oxide, 2,4,6-trimethylbenzoyl-ethoxy-phenyl phosphine oxide, bis(2,4,6-trimethylbenzoyl)-phenyl phosphine oxide, isopropylthioxanthene, any one or a combination of at least two thereof, preferably any one or a combination of at least two thereof including 2,4,6-trimethylbenzoyl-diphenyl phosphine oxide, bis(2,4,6-trimethylbenzoyl)-phenyl phosphine oxide, benzophenone, and 2,4-dimethylthioxanthene.

[0031] In the 3D printing photocurable composition of the present invention, the auxiliary agent is any one of a defoamer, an inhibitor, and an optional color paste, or a combination of at least two thereof.

[0032] The present invention also provides a method for preparing the 3D printing photocurable composition, comprising the following steps:

[0033] 1) preparing an unsaturated photocurable resin by polycondensation reaction of raw materials comprising the dicyclohexylmethane dicyanate composition of the present invention;

[0034] 2) The unsaturated photocurable resin obtained in step 1) is mixed with an acrylate compound having a (meth)acrylate functional group, a photoinitiator, and an auxiliary agent, and stirred at high speed in a blender. After being stirred evenly, the mixture is allowed to stand and defoam to obtain a 3D printing photocurable composition.

[0035] In the method of the present invention, the raw materials for the unsaturated photocurable resin reaction in step 1) also include active hydrogen polymers and acrylamide compounds. Preferably, the raw materials have a mass percentage composition of: 7-45% of dicyclohexylmethane diisocyanate composition, preferably 12-30%, more preferably 15-25%; 45-80% of active hydrogen polymers, preferably 55-75%; and 5-15% of acrylamide compounds, preferably 5-10%.

[0036] Preferably, the polycondensation reaction is carried out under a catalyst condition, and the catalyst is selected from any one or a combination of at least two of a tertiary amine catalyst (such as triethylenediamine, bis(dimethylaminoethyl) ether) and an organic metal catalyst (such as stannous octoate, n-butyltin laurate); more preferably, the amount of the catalyst in the polycondensation reaction raw material is 200 to 600 ppm;

[0037] The reaction temperature of the polycondensation reaction is 50-100°C and the reaction time is 1-12h;

[0038] In some specific examples of the present invention, the unsaturated photocurable resin raw material in step 1) is preferably prepared by the following method:

[0039] First, a dicyclohexylmethane diisocyanate composition, an active hydrogen-containing polymer, and a catalyst are mixed and reacted at 50-90° C. for 1-5 hours to obtain a prepolymer terminated with an isocyanate group; then an acrylamide compound is added and reacted at 50-90° C. until the residual NCO content reaches less than 0.25% to obtain an unsaturated photocurable resin.

[0040] In the method of the present invention, in step 2), the mixing process temperature is 25-75° C., the stirring speed is 100-800 r / min, and the stirring time is 0.2-2 h.

[0041] The viscosity of the 3D printing photocurable composition of the present invention may be lower than 3000 CP, preferably 50 to 2500 CP.

[0042] The printing conditions of the 3D printing photocurable composition of the present invention for the 3D printing process are: at a wavelength of 300-450nm, preferably 350-425nm, and an intensity of 200-4000mJ / cm 2 , preferably 400-2000mJ / cm 2 Print under ultraviolet light conditions.

[0043] The 3D printing photocurable composition of the present invention is used in the 3D printing process, and the exposure time (i.e., curing time) of the bottom layer is 1-6s, and the exposure time of each other layer is ≤2s, preferably 0.5-2s.

[0044] The 3D printing photocurable composition of the present invention has a single layer thickness of 0.001-20 mm, preferably 0.01-2 mm.

[0045] The flexibility of the 3D printed light-cured product prepared by the present invention is reflected by the number of bending times, and the product will not break after being bent at least 5,000 times.

[0046] The present invention improves the performance of dicyclohexylmethane diisocyanate by limiting the contents of different isomers in the dicyclohexylmethane diisocyanate, making it more suitable for the field of 3D printing. The 3D printing light-curing material prepared with it as a raw material has the advantages of low viscosity, shorter single-layer curing time, which can be shortened to less than 2S, low viscosity, fast printing speed, high printing efficiency, and good flexibility of printed samples. BRIEF DESCRIPTION OF THE DRAWINGS

[0047] Figure 1 is a gas chromatogram of a dicyclohexylmethane diisocyanate composition;

[0048] The reference numbers in the figure are: 1 is the solvent peak (dichloromethane), 2 is 2,4'-HMDI (four consecutive peaks), 3, 4, and 5 are all 4,4'-HMDI (three consecutive peaks), among which 3 is c,c'-HMDI, 4 is c,t'-HMDI, and 5 is t,t'-HMDI. DETAILED DESCRIPTION

[0049] The technical solution of the present invention is further described below by specific implementation methods. It should be understood by those skilled in the art that the embodiments are only to help understand the present invention and should not be regarded as specific limitations of the present invention.

[0050] In the following examples and comparative examples, the sources of the main raw materials are as follows:

[0051] Hydroxyl-terminated polypropylene glycol (PPG-1000, PPG-2000): Wanhua Chemical, industrial product.

[0052] Amino-terminated polypropylene glycol D2000 (D2000, number average molecular weight 2000): Huntsman, industrial product.

[0053] N-Hydroxyethyl acrylamide: Shanghai Ju Rui, industrial product.

[0054] Acryloylmorpholine: Double Bond Chemical Co., Ltd., industrial product.

[0055] Tricyclodecane dimethanol diacrylate: Sartomer (Guangzhou) Chemical Co., Ltd., industrial product.

[0056] 2,4,6-Trimethylbenzoyl-diphenylphosphine oxide: Double Bond Chemical Co., Ltd., industrial product.

[0057] Bis(2,4,6-trimethylbenzoyl)-phenylphosphine oxide: Double Bond Chemical Co., Ltd., industrial product.

[0058] p-Hydroxyanisole: Aladdin, reagent grade.

[0059] Defoamer: BYK 1790, industrial product;

[0060] Other materials not specifically specified are common commercially available raw materials.

[0061] Product performance testing method in the embodiment of the present invention:

[0062] Viscosity: Tested using the national standard GB / T2794-2013 method.

[0063] Bending test times: Cut the printed product into a 10cm×1cm rectangle with the same thickness as the product. Fold it 180° repeatedly to test the number of times the product needs to bend and break, which is used to evaluate the flexibility of the product.

[0064] The analysis of the related isomers of dicyclohexylmethane diisocyanate in the present invention is carried out according to the method described below:

[0065] Principle of the method: The sample is dissolved in a solvent (dichloromethane) and then analyzed by gas chromatography, detected by a hydrogen ion flame detector (FID), and the content of each isomer is quantitatively calculated by the area normalization method of all HMDI isomer peaks;

[0066]

[0067] Where:

[0068] ω——the content of a specific isomer in the sample;

[0069] A – chromatographic peak area of ​​specific isomer in the sample;

[0070] A i ——Chromatographic peak areas of all HMDI isomers in the sample.

[0071] This method uses the following instruments and equipment: gas chromatograph: with split / splitless inlet and hydrogen ion flame detector (FID) and gas chromatography workstation; chromatographic column: HP-5 (30m×320μm×0.25μm) or chromatographic column with similar stationary phase; general laboratory glass containers;

[0072] The chromatographic conditions were as follows:

[0073] Carrier gas: purified and dried high-purity nitrogen (purity ≥ 99.999%);

[0074] Combustion gas: hydrogen (purity ≥ 99.999%), flow rate 40mL / min;

[0075] Combustion-supporting gas: purified and dried air, with a flow rate of 400 mL / min;

[0076] Tail gas: nitrogen, flow rate 30mL / min;

[0077] Column flow rate: 1.06 mL / min;

[0078] Split ratio: 30:1;

[0079] Column temperature (programmed temperature rise): 140°C for 0 min, increase the temperature to 220°C at 10°C / min, maintain for 1 min, increase the temperature to 260°C at 5°C / min, maintain for 0 min, increase the temperature to 280°C at 10°C / min, maintain for 1 min;

[0080] Inlet temperature: 270°C;

[0081] Detector temperature: 290°C;

[0082] Injection volume: 0.2 μL.

[0083] Example 1

[0084] Preparation of dicyclohexylmethane dicyanate (HMDI) compositions with different isomer contents

[0085] By the method provided in Example 5 and Example 6 of patent CN101429139A, a dicyclohexylmethane diamine composition was prepared, wherein the 2,4'-HMDA content was 14.2% (A / A) and the 4,4'-HMDA content was 85.5%, and then phosgenated according to the method provided in patent CN103319372B to obtain a HMDI composition (sample 0). It should be particularly noted that the isomers do not change during the phosgenation reaction of HMDA to prepare HMDI, and the change in the amount of isomers is mainly due to the removal of impurities during the separation process. The entrainment of part of the isomers.

[0086] The gas chromatography method provided by the present invention is used to analyze the composition of sample 0, which includes 2,4'-HMDI 13.8% (A / A), 4,4'-HMDI 86.2% (A / A), of which t,t'-HMDI is 18% (A / A), c,c'-HMDI content is 23.0% (A / A), and c,t'-HMDI content is 45.2% (A / A).

[0087] The obtained HMDI composition (sample 0) was distilled again, with 25 distillation plates, 0.2 KPa pressure, and a temperature between 160-180° C. The first 10% fraction in the extraction sequence was collected as sample 1, 15-30% fraction in the extraction sequence was collected as sample 2, and 80-90% fraction in the extraction sequence was collected as sample 3. The compositions of samples 1 to 3 were analyzed by gas chromatography:

[0088] The composition of sample 1 includes 2,4'-HMDI 75.4% (A / A), 4,4'-HMDI 24.6% (A / A), of which t,t'-HMDI is 0.1% (A / A), c,c'-HMDI content is 23.2% (A / A), and c,t'-HMDI content is 1.3% (A / A).

[0089] Sample 2, the composition includes 2,4'-HMDI 1.5% (A / A), 4,4'-HMDI 98.5%, of which t,t'-HMDI content is 0.6% (A / A), c,c'-HMDI content is 29.8% (A / A), and c,t'-HMDI content is 68.1% (A / A).

[0090] Sample 3, the composition includes 2,4'-HMDI 0.1% (A / A), 4,4'-HMDI 99.9% (A / A), of which t,t'-HMDI content is 68.1% (A / A), c,c'-HMDI content is 3.1% (A / A), and c,t'-HMDI content is 28.7% (A / A).

[0091] The obtained samples 0, 1, 2, and 3 were blended in a certain ratio to obtain HMDI compositions with different isomer contents, which were named as blended samples 1 to 14, wherein the isomer contents of sample 0 and blended samples 7 to 9 met the requirements of the dicyclohexylmethane dicyanate (HMDI) composition of the present invention, and were used as raw materials of the embodiments of the present invention to prepare the 3D printing photocurable composition of the present invention. The specific blending ratios and the isomer contents of the HMDI compositions after blending are shown in Table 1 below:

[0092] Table 1 Blending ratio and isomer content of HMDI composition samples

[0093]

[0094] Example 2

[0095] Preparation of unsaturated photocurable resin and 3D printing photocurable composition

[0096] Sample 0 and blended samples 7-14 obtained in Example 1, a total of 9 HMDI compositions with different isomer contents, were used to synthesize unsaturated photocurable resins and 3D printing photocurable compositions in the following manners.

[0097] Synthesis of unsaturated light-curable resin: 136g of dicyclohexylmethane diisocyanate composition, 230g of amino-terminated polyether (D2000), 230g of hydroxy-terminated polypropylene glycol (PPG-1000), and 0.3g of catalyst bismuth neodecanoate were added to a reaction bottle equipped with a stirring device and a temperature control device, and an inert protective gas was introduced. The reaction was carried out at 70°C for 1 hour. The NCO content of the prepolymer was measured by n-butylamine titration method to be 2.53wt%. 40g of N-hydroxyethyl acrylamide was added, and the reaction was carried out at 70°C for 3 hours. The residual NCO content was measured to be 0.10wt%. The reaction was stopped to obtain an unsaturated light-curable resin.

[0098] Synthesis of 3D printing photocurable composition: 55 g of the above-mentioned unsaturated photocurable resin, 20 g of acryloylmorpholine, 25 g of tricyclodecane dimethanol diacrylate, 2 g of bis(2,4,6-trimethylbenzoyl)-phenyl phosphine oxide, 1 g of 2,4,6-trimethylbenzoyl-diphenyl phosphine oxide, 0.05 g of p-hydroxyanisole, and 0.7 g of defoamer BYK-1790 were added to a blender. At 30 ° C, the speed was 500 r / min, and the mixture was stirred for 30 min. After stirring evenly, the mixture was allowed to stand for defoaming to obtain a 3D printing photocurable composition.

[0099] Finally, 9 portions of 3D printing photocurable compositions were obtained.

[0100] Comparative Example

[0101] Preparation of unsaturated photocurable resin and photocurable composition for 3D printing

[0102] Samples 1-3 and blended samples 1-6 obtained in Example 1, a total of 9 HMDI compositions with different isomer contents, were used to synthesize unsaturated photocurable resins and 3D printing photocurable compositions according to the method of Example 2. Finally, 9 3D printing photocurable compositions were obtained.

[0103] The 9 parts of 3D printing photocurable compositions prepared in Example 2 and the 9 parts of 3D printing photocurable compositions prepared in the comparative example were used to print test samples on the L120 LCD photocurable printer of Beijing Daye 3D Co., Ltd. The number of printed layers was 80, and the thickness of a single layer was 0.05 mm. Printing was performed under the conditions of a wavelength of 405 nm and a UV lamp power of 80 W. Among them, the exposure time for printing the bottom layer was 6 seconds, and the exposure time for each other layer was adjusted according to different samples, but the exposure time for each layer did not exceed 2 seconds.

[0104] The viscosity of the 3D printing photocurable composition, the forming condition of the printed product, and the number of bends of the formed product were tested. The results are shown in Table 2 below.

[0105] Table 2 Performance test results of 3D printing photocurable compositions

[0106]

[0107] The results in Table 2 show that the viscosity of the 9 groups of photocurable compositions prepared in Example 2 is relatively low, and the curing time of each layer in the 3D printing process is short. The bending test results of the 3D printed products show that they have high flexibility. Although the 9 groups of photocurable compositions prepared in the comparative example have good individual performance indicators, there are certain defects in the overall indicators. At the same time, the single-layer photocuring time in the examples is less than 2S, which is 33% shorter than the normal photocuring time of more than 3S, and the 3D printing production efficiency is increased by 50%.

[0108] The present invention illustrates the detailed method of the present invention through the above-mentioned embodiments, but the present invention is not limited to the above-mentioned detailed method, that is, it does not mean that the present invention must rely on the above-mentioned detailed method to be implemented. Those skilled in the art should understand that any improvement of the present invention, equivalent replacement of various raw materials of the product of the present invention, addition of auxiliary components, selection of specific methods, etc., all fall within the protection scope and disclosure scope of the present invention.

Claims

1. A dicyclohexylmethane dicyanate composition, characterized in that: The dicyclohexylmethane dicyanate composition contains isomers 2,4'-dicyclohexylmethane diisocyanate and 4,4'-dicyclohexylmethane diisocyanate at the same time; wherein the content of the 2,4'-dicyclohexylmethane diisocyanate is 2-20wt%; The 4,4'-dicyclohexylmethane diisocyanate includes three isomers of cis,cis'-dicyclohexylmethane diisocyanate, cis,trans'-dicyclohexylmethane diisocyanate, and trans,trans'-dicyclohexylmethane diisocyanate. Taking the mass of the dicyclohexylmethane diisocyanate composition as 100%, the content of trans,trans'-dicyclohexylmethane diisocyanate is 5-30%.

2. The composition according to claim 1, characterized in that The content of the 2,4'-dicyclohexylmethane diisocyanate is 4 to 15 wt%.

3. The composition according to claim 2, characterized in that The content of the 2,4'-dicyclohexylmethane diisocyanate is 6 to 12 wt%.

4. The composition according to claim 1, characterized in that The content of trans, trans'-dicyclohexylmethane diisocyanate is 7-25%.

5. The composition according to claim 4, characterized in that The content of trans, trans'-dicyclohexylmethane diisocyanate is 8-25%.

6. Application of the dicyclohexylmethane dicyanate composition according to claim 1 in the field of 3D printing.

7. The use according to claim 6, characterized in that: Suitable for preparing 3D printing light-curing materials and 3D printing flexible materials.

8. A 3D printing photocurable composition, characterized in that: Taking the total mass of the raw materials of the 3D printing photocurable composition as 100%, the raw material composition includes: 35-75 wt % of an unsaturated photocurable resin, wherein the unsaturated photocurable resin is prepared from the dicyclohexylmethane dicyanate composition according to any one of claims 1 to 5; 18-54 wt % of an acrylate compound having a (meth)acrylate functional group; Photoinitiator 0.5-10wt%; Additives 0.1~3wt%.

9. The 3D printing photocurable composition according to claim 8, characterized in that: The raw material composition includes: Unsaturated light-curing resin 45-65wt%; 35-50 wt % of an acrylate compound having a (meth)acrylate functional group; Photoinitiator 1-4.5wt%; Additives 0.1~3wt%.

10. The 3D printing photocurable composition according to claim 8, characterized in that: The unsaturated photocurable resin is prepared by reacting the dicyclohexylmethane diisocyanate composition according to any one of claims 1 to 5, a polymer containing active hydrogen, and any one or a combination of at least two selected from acrylamide compounds, acrylic acid, methacrylic acid, hydroxyethyl acrylate, hydroxyethyl methacrylate, and N-vinyl pyrrolidone as raw materials.

11. The 3D printing photocurable composition according to claim 10, characterized in that: Taking the total mass of the raw materials for preparing the unsaturated photocurable resin as 100%, the raw material composition includes: Dicyclohexylmethane diisocyanate composition 7-45%; Contains 45-80% active hydrogen polymer; Acrylamide compound 5-15%.

12. The 3D printing photocurable composition according to claim 11, characterized in that: The raw materials include: 12-30% of dicyclohexylmethane diisocyanate composition; Contains 55-75% active hydrogen polymer; Acrylamide compound 5-10%.

13. The 3D printing photocurable composition according to claim 10, characterized in that: The active hydrogen-containing polymer is selected from any one or a combination of at least two of amino-terminated polypropylene glycol, hydroxyl-terminated polytetrahydrofuran, hydroxyl-terminated polypropylene glycol, polyethylene glycol, polypropylene glycol, polytetrahydrofuran diol, polycaprolactone diol, polylactic acid diol, polyethylene adipate diol, polybutylene adipate diol, polybutadiene diol, 2,2-dimethylol propionic acid, and N-methyldiethanolamine with a molecular weight between 1000 and 2000; The acrylamide compound is acrylamide, any one of N-isopropyl acrylamide, N-hydroxyethyl acrylamide, and N-hydroxypropyl acrylamide, or a combination of at least two thereof.

14. The 3D printing photocurable composition according to claim 8, characterized in that: The acrylate compound with a (meth)acrylate functional group is a mixture of a monofunctional (meth)acrylate and a high-functionality (meth)acrylate, wherein the monofunctional (meth)acrylate comprises any one of hydroxyethyl (meth)acrylate, dicyclopentadiene (meth)acrylate, tetrahydrofuran (meth)acrylate, isobornyl (meth)acrylate, trimethylolpropane formal acrylate, and acryloylmorpholine, or a combination of at least two thereof; the high-functionality (meth)acrylate comprises any one of cyclohexanedimethanol 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, and ethoxylated pentaerythritol tetra(meth)acrylate, or a combination of at least two thereof; The photoinitiator is any one of 2-hydroxy-2-methyl-1-phenyl-1-propanone, 1-hydroxycyclohexyl phenyl ketone, 2-hydroxy-2-methyl-p-hydroxyethyl ether phenyl-1-propanone, 2-benzyl-2-dimethylamino-1-(4-morpholinophenyl)-1-butanone, 2,4,6-trimethylbenzoyl-diphenyl phosphine oxide, 2,4,6-trimethylbenzoyl-ethoxy-phenyl phosphine oxide, bis(2,4,6-trimethylbenzoyl)-phenyl phosphine oxide, isopropyl thioxanthene, benzophenone, and 2,4-dimethyl thioxanthene, or a combination of at least two thereof; The auxiliary agent is any one of a defoamer, an inhibitor, and an optional color paste, or a combination of at least two of them.

15. The 3D printing photocurable composition according to claim 8, characterized in that: The viscosity of the 3D printing photocurable composition is less than 3000 CP; The printing conditions of the 3D printing photocurable composition for the 3D printing process are: a wavelength of 300-450nm, and an ultraviolet light intensity of 200-4000 mJ / cm 2 ; The exposure time for printing the bottom layer is 1-6s, and the exposure time for each other layer is ≤2s; Print single layer thickness 0.001-20mm.

16. The 3D printing photocurable composition according to claim 15, characterized in that: The viscosity of the 3D printing photocurable composition is 50-2500 CP.

17. The 3D printing photocurable composition according to claim 15, characterized in that: The printing conditions of the 3D printing photocurable composition for the 3D printing process are: wavelength of 350-425nm, ultraviolet light intensity of 400-2000mJ / cm 2 .

18. The 3D printing photocurable composition according to claim 15, characterized in that: The exposure time of each other layer is 0.5-2s; Print single layer thickness 0.01-2mm.

19. A method for preparing the 3D printing photocurable composition according to any one of claims 8 to 18, characterized in that: The following steps are involved: 1) preparing an unsaturated photocurable resin by polycondensation reaction of a raw material comprising the dicyclohexylmethane dicyanate composition according to any one of claims 1 to 5; 2) The unsaturated photocurable resin obtained in step 1) is mixed with an acrylate compound having a (meth)acrylate functional group, a photoinitiator, and an auxiliary agent, and stirred at high speed in a blender. After being stirred evenly, the mixture is allowed to stand and defoam to obtain a 3D printing photocurable composition.

20. The preparation method according to claim 19, characterized in that: Step 1) The polycondensation reaction is carried out under a catalyst condition, and the catalyst is selected from any one of a tertiary amine catalyst and an organic metal catalyst, or a combination of at least two of them.

21. The preparation method according to claim 20, characterized in that: The catalyst is selected from any one of triethylenediamine, bis(dimethylaminoethyl)ether, stannous octoate, and n-butyltin laurate, or a combination of at least two thereof.

22. The preparation method according to claim 20, characterized in that: The amount of the catalyst used in the polycondensation reaction raw material is 200 to 600 ppm.

23. The preparation method according to claim 19, characterized in that: Step 1) The reaction temperature of the polycondensation reaction is 50-100° C., and the reaction time is 1-12 hours.

24. The preparation method according to claim 19, characterized in that: The preparation method of the unsaturated light-curable resin raw material in step 1) is: First, a dicyclohexylmethane diisocyanate composition, an active hydrogen-containing polymer, and a catalyst are mixed and reacted at 50-90° C. for 1-5 hours to obtain a prepolymer terminated with an isocyanate group; then an acrylamide compound is added and reacted at 50-90° C. until the residual NCO content reaches less than 0.25% to obtain an unsaturated photocurable resin.

25. The preparation method according to claim 19, characterized in that: In step 2), the mixing process temperature is 25-75° C., the stirring speed is 100-800 r / min, and the stirring time is 0.2-2 h.

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