Universal light-cured resin preparation method

Abstract

The invention provides a universal light-cured resin preparation method, and relates to the technical field of light-cured resin preparation, and the method comprises the following steps: S1, preparation of microcrystalline wax-LMA; s2, preparing an acrylic resin matrix; s3, adding microcrystalline wax-LMA and other fillers into the acrylic resin matrix, and stirring and mixing; s4, then adding a diluent and other additives, and stirring and mixing; and S5, adding a compound photoinitiator, and stirring and mixing to obtain a finished product. Through the compound photoinitiator, the surface and the deep layer of the material are synchronously cured, and almost no curing stress exists, so that the material can be cured into a sheet layer without any buckling deformation in a sunken DLP (Digital Light Processing); and secondly, the microcrystalline wax-LMA forms a microphase separation structure in the material, so that the shrinkage and cracking of the material are greatly reduced, and the effects of improving the strength and the toughness can be achieved.

Description

Technical Field

[0001] The invention relates to the technical field of photocurable resin preparation, in particular to a general photocurable resin preparation method. Background Art

[0002] 3D printing printers that use a wavelength of 405 nm are generally divided into LCD printing and DLP printing. DLP stands for digital light processing, which uses a digital projector to project the image of an entire layer onto the resin tank at once, so each layer cures quickly. LCD light curing may refer to a technology that uses an LCD as a mask. It selectively transmits light through the LCD screen, allowing ultraviolet rays to pass through specific areas to cure the resin. Therefore, LCDs are cheap, have relatively slow curing speeds, weak light intensity, and low light uniformity. DLP is the opposite.

[0003] However, the photosensitive resin materials used in existing LCD and DLP printing are usually highly specialized and have the problem of limited versatility. In addition, the photosensitive resin will shrink in volume during the curing process, especially under deep curing conditions. This phenomenon is particularly obvious. The shrinkage not only causes deviations in the size of the finished product, but may also cause internal stress concentration, ultimately causing cracking or deformation. Summary of the Invention

[0004] The present invention aims to address the shortcomings of the background technology and provide a method for preparing a universal photocurable resin, which solves the problems of poor versatility and easy shrinkage and cracking of the material. Microcrystalline wax (LMA) forms a microphase separation structure in the material, greatly reducing the shrinkage and cracking of the material, and can achieve the effect of improving strength and toughness.

[0005] To achieve the above object, the present invention provides the following technical solution: a method for preparing a universal photocurable resin, comprising:

[0006] S1. Preparation of microcrystalline wax-LMA;

[0007] S2, preparing an acrylic resin matrix;

[0008] S3, adding microcrystalline wax-LMA and other fillers into the above acrylic resin matrix, stirring and mixing;

[0009] S4, then add diluent and other additives, stirring and mixing;

[0010] S5. Add a composite photoinitiator, stir and mix to obtain a finished product.

[0011] The specific steps of S1 are as follows:

[0012] S11, preparing microcrystalline wax (BASF A wax) and lauryl acrylate (LMA), wherein the ratio of microcrystalline wax (BASF A wax) to lauryl acrylate (LMA) is 15% and the ratio of LMA to microcrystalline wax is 85%.

[0013] S12, then mixing the microcrystalline wax with LMA, and stirring at 105° C. at a speed of 300-500 rpm for 10 minutes;

[0014] S13. After the stirring is completed, the mixture is cooled to 8°C-10°C to form a stable microcrystalline wax-LMA.

[0015] The specific steps of S2 are as follows:

[0016] S21, prepare 35-50 parts of acrylic resin, composed of 5-20 parts of epoxy acrylate and 15-45 parts of polyurethane acrylate, wherein preferably 50 parts of acrylic resin, 20 parts of epoxy acrylate, and 30 parts of polyurethane acrylate;

[0017] S22, 0.3 parts of dispersant, which is a BYK dispersant, including one or more of BYK 2205, DISPERBYK-2013, BYK-1811, and BYK-110;

[0018] S23, then mixing and stirring at 60°C at a speed of 2000-2500 rpm for 30 minutes.

[0019] The specific steps of S3 are as follows:

[0020] S31, prepare 0.1-3 parts of microcrystalline wax-LMA, preferably 2.5 parts of microcrystalline wax-LMA, 5 parts of LMA and 2 parts of active calcium;

[0021] S32, gradually adding the above materials to the acrylic resin matrix prepared in step S23;

[0022] S33, stirring at 100°C and 500 rpm for 5 minutes, and then cooling to 50°C.

[0023] The specific steps of S4 are as follows:

[0024] S41, prepare 25 parts of DPGDA, 15 parts of 3EOTMPTA, 10 parts of ACMO and 0.3 parts of color paste;

[0025] S42. Add the above materials at 50°C and stir at a low speed of 500 rpm for 30 minutes.

[0026] Among them, the specific steps of S5 are as follows;

[0027] S51. Prepare a composite photoinitiator, comprising 0.3-1.5 parts of TPO, 0.05-0.3 parts of ITX, and 0.5-2 parts of EDAB, preferably 1.2 parts of TPO, 0.15 parts of ITX, and 1 part of EDAB;

[0028] S52. Add the above materials at 50°C and stir at 500 rpm for 30 minutes to ensure that the photoinitiator is fully mixed to obtain the finished product.

[0029] The present invention provides a method for preparing a universal photocurable resin, which has the following beneficial effects:

[0030] The advantages of the present invention are that the composite photoinitiator can simultaneously cure the surface and deep layers of the material, with almost no curing stress, so that even in a sinking DLP, it can be cured into a sheet without any warping or deformation.

[0031] Secondly, microcrystalline wax - LMA, forms a microphase separation structure in the material, greatly reducing the shrinkage and cracking of the material, and can achieve the effect of improving strength and toughness. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] Figure 1 It is a flow chart of the preparation method of the present invention.

[0033] Figure 2 This is a specific flow chart of step S1 of the present invention.

[0034] Figure 3 This is a specific flow chart of step S2 of the present invention.

[0035] Figure 4 This is a specific flow chart of step S3 of the present invention.

[0036] Figure 5 This is a specific flow chart of step S4 of the present invention.

[0037] Figure 6 This is a specific flow chart of step S5 of the present invention.

[0038] Figure 7 Schematic diagram of the standard precision test piece of the present invention. DETAILED DESCRIPTION

[0039] The following will be combined with the drawings in the embodiments of the present application to clearly and completely describe the technical solutions in the embodiments of the present application. Obviously, the embodiments described are only part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without making creative efforts are within the scope of protection of this application.

[0040] The disclosure below provides many different embodiments or examples for realizing different structures of the present application. In order to simplify the disclosure of the present application, the components and settings of specific examples are described below. Of course, they are merely examples and are not intended to limit the present application. In addition, the present application may repeat reference numbers and / or reference letters in different examples, and such repetition is for the purpose of simplicity and clarity, and does not itself indicate the relationship between the various embodiments and / or settings discussed. In addition, the present application provides examples of various specific processes and materials, but those of ordinary skill in the art will appreciate the application of other processes and / or the use of other materials.

[0041] The present invention provides a method for preparing a universal photocurable resin, which is described in detail below. It should be noted that the order in which the following embodiments are described is not intended to limit the preferred order of the embodiments.

[0042] The following describes the present application in detail with reference to the accompanying drawings and specific implementation methods. Figure 1-7 In this embodiment, a general method for preparing a photocurable resin is provided, comprising:

[0043] S1. Preparation of microcrystalline wax-LMA;

[0044] S2, preparing an acrylic resin matrix;

[0045] S3, adding microcrystalline wax-LMA and other fillers into the above acrylic resin matrix, stirring and mixing;

[0046] S4, then add diluent and other additives, stirring and mixing;

[0047] S5. Add a composite photoinitiator, stir and mix to obtain a finished product.

[0048] The specific steps of S1 are as follows:

[0049] S11, preparing microcrystalline wax (BASF A wax) and lauryl acrylate (LMA), wherein the ratio of microcrystalline wax (BASF A wax) to lauryl acrylate (LMA) is 15% and the ratio of LMA to microcrystalline wax is 85%.

[0050] S12. Then mix the microcrystalline wax with LMA and stir at 105°C at a speed of 300-500 rpm for 10 minutes. During the stirring process, ensure that the temperature is evenly distributed to avoid local overheating that may cause decomposition of components. At the same time, the stirring speed should not be too high to avoid introducing bubbles. If undissolved particles are found in the mixture, it may be due to insufficient temperature or stirring time. The heating time and stirring time can be appropriately extended.

[0051] S13. After stirring, cool the mixture to 8℃-10℃. A cooling water bath or refrigerator can be used to form a stable microcrystalline wax-LMA. Slow cooling helps to form a more stable microphase separation structure. Rapid cooling may lead to incomplete crystallization. If incomplete crystallization occurs, it may be caused by too fast cooling. At this time, the cooling rate can be adjusted or the cooling time can be extended.

[0052] The specific steps of S2 are as follows:

[0053] S21, prepare 35-50 parts of acrylic resin, composed of 5-20 parts of epoxy acrylate and 15-45 parts of polyurethane acrylate, wherein preferably the acrylic resin is 50 parts, the epoxy acrylate is 20 parts, and the polyurethane acrylate is 30 parts;

[0054] S22, 0.3 parts of dispersant, which is a BYK dispersant, including one or more of BYK 2205, DISPERBYK-2013, BYK-1811, and BYK-110. The dispersant can promote the stability of the microphase separation structure when microcrystalline wax is added later;

[0055] S23, then mixing and stirring at 60°C at a speed of 2000-2500 rpm for 30 minutes to build a resin base and ensure uniform dispersion of subsequent ingredients;

[0056] During the stirring process, ensure that the temperature is controlled at around 60°C. A temperature that is too high will accelerate the reaction and affect the final performance. Also, pay attention to whether there are bubbles when stirring. If a large number of bubbles are found during the stirring process, reduce the stirring speed to reduce the bubbles.

[0057] The specific steps of S3 are as follows:

[0058] S31, preparing 0.1-3 parts of microcrystalline wax-LMA, preferably 2.5 parts of microcrystalline wax-LMA, 5 parts of LMA and 2 parts of active calcium, and the synergistic effect of microcrystalline wax-LMA and active calcium further reduces the shrinkage rate of the material and reduces the risk of cracking;

[0059] S32, gradually adding the above materials to the acrylic resin matrix prepared in step S23 to avoid agglomeration caused by adding a large amount at one time;

[0060] S33, stirring at 500 rpm for 5 minutes at 100°C. During the stirring process, the temperature must be kept constant to prevent local overheating or overcooling from affecting the solubility of the components. If it is found that some components are not fully dissolved, check whether the temperature meets the requirements and increase the stirring time appropriately;

[0061] Then cool to 50℃, and the cooling process should be smooth to avoid sudden temperature changes causing component separation;

[0062] Among them, after the microcrystalline wax is dissolved at high temperature, it can be evenly dispersed with the active calcium in the acrylic resin and LMA monomer liquid. At the same time, due to the steric hindrance effect of the dispersant, they maintain a stable suspended dispersion state. In addition, since the active calcium is modified, it contains hydrogen bonds (which can form a network structure by itself). Although the active calcium has a relatively high specific gravity, the microcrystalline wax has a low specific gravity. The two are organically combined through the connection of the dispersant to form a more stable network structure.

[0063] For the final product, it can reduce shrinkage (5% to 0.2%) and cracking, and the lubrication and low surface tension of the wax promote the smoothness of the surface. The low wax content and the presence of hydrogen bonds in the components do not affect the adhesion between layers. At the same time, the wax has a certain oxygen inhibition effect.

[0064] The specific steps of S4 are as follows:

[0065] S41, prepare 25 parts of DPGDA, 15 parts of 3EOTMPTA, 10 parts of ACMO and 0.3 parts of color paste to adjust the resin viscosity;

[0066] S42. Add the above materials at 50°C and stir at a low speed of 500 rpm for 30 minutes to ensure that the diluent and additives are evenly mixed while maintaining the established network structure. At the same time, check the state of the mixture regularly during the stirring process to ensure that there is no precipitation or stratification.

[0067] Among them, the specific steps of S5 are as follows;

[0068] S51. Prepare a composite photoinitiator, comprising 0.3-1.5 parts of TPO, 0.05-0.3 parts of ITX, and 0.5-2 parts of EDAB, preferably 1.2 parts of TPO, 0.15 parts of ITX, and 1 part of EDAB, to achieve a balance between surface and deep curing and improve curing efficiency. The photoinitiator is light-sensitive and should be operated in a dark environment to avoid premature activation of the photoinitiator.

[0069] S52. Add the above materials at 50°C and stir at 500 rpm for 30 minutes to ensure that the photoinitiator is fully mixed to obtain the finished product;

[0070] Among them, the compounding of TPO and ITX can promote the balanced curing of the deep layer and surface of the material. At the same time, because ITX has a higher absorption peak at the wavelength of 405, it will rob some of the light energy required by TPO. Moreover, with the help of amine accelerators such as EDAB, ITX is more active, so the content of ITX is much lower than that of TPO.

[0071] After testing, the ITX content is 1 / 5-1 / 10 of TPO, which will greatly reduce the robbing of light energy. A small amount of amine accelerator has little effect on TPO. When it is greater than 0.5%, it can accelerate curing and have a positive effect on ITX.

[0072] The photoinitiator with this compound ratio can make ITX and TPO perform their respective functions, promote the balanced curing of the deep layer and surface of the material, and the overall amount of photoinitiator used is relatively small, which will not cause large stress accumulation, which also solves the problem of material printing and molding on different equipment.

[0073] To facilitate understanding of the uniqueness and innovation of the present invention, the following examples are provided according to the above-mentioned preparation method:

[0074] Among them, the content of each component of the formula must meet the following conditions:

[0075] Polyurethane acrylate and epoxy acrylate resin: 35-50 parts;

[0076] Acrylic resin monomer: 30-50 parts;

[0077] Microcrystalline wax-LMA: 0.1-3 parts;

[0078] TPO: 0.3-1.5 parts;

[0079] ITX: 0.05-0.3 parts;

[0080] EDAB: 0.5-2 parts

[0081]

[0082]

[0083] The molding effect is verified on different printers as follows: The test samples are: standard precision test pieces such as Figure 7 :

[0084]

[0085]

[0086] In the above embodiments, the description of each embodiment has its own focus. For parts that are not described in detail in a certain embodiment, reference can be made to the relevant descriptions of other embodiments.

[0087] In order to verify the uniqueness and innovation of the present invention, the following comparative examples are set for comparison:

[0088]

[0089]

[0090] Among them, Comparative Examples 1 and 2 removed the microcrystalline wax-LMA. It can be observed that the effect of this ingredient on printing molding is to improve the smoothness and somewhat reduce the phenomenon of surface shrinkage and warping.

[0091] Comparative Example 3: The microcrystalline wax-LMA was increased beyond the formulation range, resulting in obvious delamination in the printing. This is because the microcrystalline wax reduced the surface tension of the material too much, affecting the layer adhesion.

[0092] Comparative Example 4, in which ITX and EDAB were removed, exhibited significant edge warping in the sink-down printer. This was due to the lack of a combination of these two initiators, resulting in uneven curing speeds from top to bottom during single-layer exposure. The lack of pressure coverage in the sink-down printer caused the material to shrink and warp.

[0093] In Comparative Example 5, the TPO ratio was lowered and the ITX ratio was increased. However, the material only worked in lift-off DLP printing, with delamination. This was due to energy competition between ITX and TPO. The ITX-induced curing efficiency was higher, accelerating the curing of shallow layers while hindering the curing of deeper layers. This resulted in the material failing to meet the requirements of LCD exposure, which uses relatively low light energy. Furthermore, in sink-down DLP printing, layer shrinkage was exacerbated, leading to print failure.

[0094] In Comparative Example 6, when the ACMO content was increased to 20 parts, the material exhibited significant edge warping during submerged DLP printing. This was due to the excessively high overall monomer content, which increased the shrinkage of the material.

[0095]

[0096]

[0097] The above is a detailed introduction to a general photocurable resin preparation method provided in the embodiments of the present application. Specific examples are used herein to illustrate the principles and implementation methods of the present application. The description of the above embodiments is only used to help understand the technical solutions and core ideas of the present application. Ordinary technicians in this field should understand that they can still modify the technical solutions recorded in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein. These modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present application.

Claims

1. A method for preparing a universal light-curing resin, characterized in that: include: S1. Preparation of microcrystalline wax-LMA; S2, preparing an acrylic resin matrix; S3, adding microcrystalline wax-LMA and other fillers into the acrylic resin matrix, stirring and mixing; S4, then add diluent and other additives, stirring and mixing; S5. Add a composite photoinitiator, stir and mix to obtain a finished product.

2. The method for preparing a universal photocurable resin according to claim 1, wherein: The specific steps of S1 are as follows: S11, preparing microcrystalline wax (BASF A wax) and lauryl acrylate (LMA), wherein the ratio of microcrystalline wax (BASF A wax) to lauryl acrylate (LMA) is 15% and the ratio of LMA to microcrystalline wax is 85%. S12, then mixing the microcrystalline wax with LMA, and stirring at 105° C. at a speed of 300-500 rpm for 10 minutes; S13. After the stirring is completed, the mixture is cooled to 8°C-10°C to form a stable microcrystalline wax-LMA.

3. The method for preparing a universal photocurable resin according to claim 1, wherein: The specific steps of S2 are as follows: S21, prepare 35-50 parts of acrylic resin, composed of 5-20 parts of epoxy acrylate and 15-45 parts of polyurethane acrylate, wherein preferably 50 parts of acrylic resin, 20 parts of epoxy acrylate, and 30 parts of polyurethane acrylate; S22, 0.3 parts of dispersant, which is a BYK dispersant, including one or more of BYK 2205, DISPERBYK-2013, BYK-1811, and BYK-110; S23, then mixing and stirring at 60°C at a speed of 2000-2500 rpm for 30 minutes.

4. The method for preparing a universal photocurable resin according to claim 1, wherein: The specific steps for S3 are as follows: S31, prepare 0.1-3 parts of microcrystalline wax-LMA, preferably 2.5 parts of microcrystalline wax-LMA, 5 parts of LMA and 2 parts of active calcium; S32, gradually adding the above materials to the acrylic resin matrix prepared in step S23; S33, stirring at 100°C and 500 rpm for 5 minutes, and then cooling to 50°C.

5. The method for preparing a universal photocurable resin according to claim 1, wherein: The specific steps of S4 are as follows: S41, prepare 25 parts of DPGDA, 15 parts of 3EOTMPTA, 10 parts of ACMO and 0.3 parts of color paste; S42. Add the above materials at 50°C and stir at a low speed of 500 rpm for 30 minutes.

6. The method for preparing a universal photocurable resin according to claim 1, wherein: The specific steps of S5 are as follows; S51. Prepare a composite photoinitiator, comprising 0.3-1.5 parts of TPO, 0.05-0.3 parts of ITX, and 0.5-2 parts of EDAB, preferably 1.2 parts of TPO, 0.15 parts of ITX, and 1 part of EDAB; S52. Add the above materials at 50°C and stir at 500 rpm for 30 minutes to ensure that the photoinitiator is fully mixed to obtain the finished product.

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