Water-soluble 3D printing support material and preparation method thereof

Abstract

The invention discloses a water-soluble 3D printing support material, which is suitable for being matched with a waxy structure material to print a 3D object, and comprises the following components: 50-80% of polyethylene glycol; 18.5% to 37.5% of super absorbent resin; 1%-10% of polypropylene glycol; and 0.1%-3% of an antioxidant. According to the water-soluble 3D printing supporting material, the consumption of a chemical solvent during model cleaning and the subsequent treatment cost are remarkably reduced, and the water-soluble 3D printing supporting material is more environmentally friendly. The material can provide an effective supporting model suspension part with enough strength in the printing process, and meanwhile, after printing is completed, the supporting material is easily separated from a structure model in the washing process and is rapidly dissolved in water, and the obtained model is clear in details.

Description

Technical Field

[0001] The present invention relates to the field of preparation of 3D printing materials, and in particular to a water-soluble 3D printing support material and a preparation method thereof. Background Art

[0002] With the rapid development of three-dimensional printing technology (3D printing), it has shown great application potential in many fields such as manufacturing, prototyping, artistic creation and personalized customization. Among the many 3D printing technologies, MultiJet Printing (MJP) technology is favored for its high precision, multi-material compatibility and rapid prototyping capabilities. MJP technology builds three-dimensional objects by spraying multiple materials in layers, which is particularly suitable for the manufacture of complex structures and high-detail models. However, when using MJP technology for 3D printing, support materials are usually required to support the suspended parts and ensure the integrity of the model structure.

[0003] The amount of support materials used in MJP technology is considerable, especially when printing models with a large number of suspended structures or fine internal channels. These support structures not only increase the material cost during the printing process, but also need to be removed in the subsequent model processing, further increasing the processing time and complexity. Traditional methods of removing support materials mainly rely on soaking and cleaning with chemical solvents such as ethanol. This step not only consumes a large amount of chemical solvents, increasing the overall printing cost, but the treatment and discharge of chemical solvents may also have an adverse impact on the environment. The industry has also tried to use water-soluble support materials to solve the above problems. For example, patent CN103476570B uses ethoxylated fatty alcohols to prepare water-dispersible support materials, but it can only be water-dispersed. Incomplete support removal will affect the clarity of the structural model. For example, patent CN107868433A uses water-soluble tackifying resin materials to reduce the water dissolution rate. In addition, patent CN115197558B uses alkyl glycols and materials with a higher addition ratio, but the strength is still insufficient during printing.

[0004] Therefore, there is an urgent need for a support material that dissolves quickly in water, has sufficient strength, is easy to remove, and does not affect the clarity of the structural model. Summary of the invention

[0005] In order to solve the above technical problems, the present invention provides a water-soluble 3D printing support material and a preparation method thereof. The water-soluble 3D printing support material of the present invention not only significantly reduces the consumption of chemical solvents and subsequent processing costs during model cleaning, but is also more environmentally friendly. In addition, the material can provide sufficient strength to effectively support the suspended part of the model during the printing process. At the same time, after printing is completed, during the water washing process, the support material is easily detached from the structural model and quickly dissolved in water, and the details of the obtained model are clear.

[0006] The present invention adopts the following technical solutions:

[0007] A water-soluble 3D printing support material is suitable for printing 3D objects in combination with a waxy structural material. The water-soluble 3D printing support material comprises the following components by weight percentage:

[0008]

[0009] In the present invention, the amount of polyethylene glycol can be 50%, 51%, 52%, 54%, 56%, 60%, 64%, 68%, 72%, 76%, 80% and the like based on weight percentage.

[0010] In the present invention, the amount of the super absorbent resin can be 18.5%, 19%, 20%, 22%, 24%, 26%, 28%, 30%, 32%, 34%, 36%, 37.5%, etc. by weight.

[0011] In the present invention, the amount of polypropylene glycol can be 1%, 2%, 3%, 4%, 5%, 6%, 7%, 8%, 9%, 10%, etc., calculated by weight percentage.

[0012] In the present invention, the antioxidant can be used in an amount of 0.1%, 0.2%, 0.5%, 0.8%, 1%, 1.2%, 1.5%, 2%, 2.2%, 2.5%, 3%, etc., based on weight percentage.

[0013] In the present invention, the molecular weight of the polyethylene glycol is 800 to 20000, such as 800, 1000, 1200, 1400, 1600, 2000, 3000, 4000, 5000, 6000, 8000, 12000, 16000, 20000, etc. The polyethylene glycol (PEG) is selected to have high water solubility, and the effect of water dissolution can be achieved. The PEG with a molecular weight of 800-20000 is solid or close to solid at room temperature, and has a suitable melting point after heating, which can better meet the needs of MJP injection.

[0014] Wax structural materials refer to materials that use non-polar aliphatic hydrocarbons as the main component and are used for printing molding models. For example, structural materials are obtained by mixing refined paraffin wax, microcrystalline wax, and non-polar tackifying resin by heating and stirring.

[0015] Furthermore, the molecular weight of the polyethylene glycol is preferably 1000-8000, such as 1000, 1200, 1400, 1600, 2000, 3000, 4000, 5000, 6000, 8000, etc. PEG with a molecular weight of 1000-8000 is preferred, as its melting point and viscosity are better matched with the conditions, and its water dissolution rate is also faster.

[0016] In the present invention, the molecular weight of the polypropylene glycol is 800 to 2000. The selection of polypropylene glycol (PPG) can ensure compatibility with PEG and prepare a support material with a uniform state. PPG with a molecular weight less than 600 is soluble in water, which seems to be beneficial for preparing water-soluble materials, but the present invention selects PPG with a molecular weight greater than or equal to 800. Although the large molecular weight PPG is insoluble in water, it will adhere to the surface of the model material in a small amount during the cleaning of the model. The model will not turn white after cleaning, and the cleaned model will be clearer, and it will help to peel off the structural model after PEG is dissolved.

[0017] Furthermore, it is preferred that the molecular weight of the polypropylene glycol is 800.

[0018] In the present invention, the super absorbent resin includes at least one of alginic acid, alginate, starch acrylate polymer, polyacrylic acid, and polyacrylate.

[0019] Generally speaking, highly absorbent resins such as sodium polyacrylate are soluble in water but insoluble in alcohols such as ethanol. However, the present invention combines high molecular weight polyethylene glycol with highly absorbent resins, so that during the process of mixed preparation of support materials, most of the molecular chains of highly absorbent resins such as sodium polyacrylate remain in a curled state, and during the process of removing the support and dissolving, the highly absorbent resins absorb water, stretch and swell, accelerating the process of removing the support material.

[0020] Preferably, the super absorbent resin comprises sodium polyacrylate with a molecular weight of 1000-10000. The molecular weight of sodium polyacrylate can be 1000, 1200, 1400, 1800, 2000, 3000, 4000, 5000, 6000, 7000, 8000, 9000, 10000, etc.

[0021] Further, the amount and molecular weight of sodium polyacrylate can be controlled, and the degree of expansion and disintegration during the water dissolution process can be controlled so as not to affect the structural model. For example, sodium polyacrylate with a molecular weight of 1000-10000 can be dissolved in water, and within the addition ratio range selected by the present invention, the support removal process will not damage the model details.

[0022] In the present invention, the antioxidant includes at least one of β-(3.5-di-tert-butyl-4-hydroxyphenyl) propionate, tris(2,4-tert-butylphenyl) phosphite, distearyl thiodipropionate, and phenolic 2,6-di-tert-butyl-p-cresol.

[0023] Preferably, the antioxidant is octadecyl β-(3.5-di-tert-butyl-4-hydroxyphenyl) propionate.

[0024] A method for preparing a water-soluble 3D printing support material according to claim 1, the preparation method comprising the following steps:

[0025] Weigh the raw materials of each component according to the proportion, mix the raw materials of each component, heat and stir at 70-150°C, and gradually melt to form a uniformly mixed liquid;

[0026] The mixed liquid is filtered and cooled.

[0027] In the present invention, heating and stirring are carried out at 70-150°C, which can be 70°C, 75°C, 85°C, 95°C, 105°C, 115°C, 125°C, 135°C, 145°C, 150°C, etc.

[0028] Compared with the prior art, the present invention has the following advantages:

[0029] 1. As supporting materials, the selected PEG and super absorbent resin are both polar and incompatible with non-polar waxy structural materials; the melting point of the supporting material of the present invention is higher than that of the supporting material based on hard alcohol commonly used on the market, and it can be quickly cooled during the printing process to avoid mixing with the waxy structural material, so that it is not easy to be miscible with the waxy structural material, and the printed model is easy to clean.

[0030] 2. In the formula combination, most of the molecular chains of the super absorbent resin remain in a curled state, but in the process of removing the support and dissolving, they will absorb water, stretch and swell, accelerating the removal process of the support material.

[0031] 3. Choosing polypropylene glycol can ensure compatibility with the support material and prepare a support material with a uniform state; choosing polypropylene glycol with a molecular weight greater than 800. Although high molecular weight polypropylene glycol is insoluble in water, a small amount of it will adhere to the surface of the model material during cleaning. The model will not turn white after cleaning, and the cleaned model will be clearer. It also helps to dissolve the polyethylene glycol and peel it off from the structural material. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] Figure 1 It is a schematic diagram of the material stability results;

[0033] Figure 2 A schematic diagram of the support collapse of Comparative Example 2;

[0034] Figure 3 This is a detailed picture of the model after the support is washed away in comparative example 5. DETAILED DESCRIPTION

[0035] The present invention will be further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention, rather than to limit the present invention.

[0036] Example 1

[0037] 60% polyethylene glycol with a molecular weight of 1000 (PEG-1000 from Nantong Chenrun Chemical Co., Ltd.);

[0038] 30% of sodium polyacrylate PAA-Na-1200 with a molecular weight of 1200 (Zhongyan New Materials Co., Ltd.);

[0039] 9.9% polypropylene glycol with a molecular weight of 800 (PPG1 from Jiangsu Haian Petrochemical 8 000);

[0040] 0.1% antioxidant β-(3,5-di-tert-butyl-4-hydroxyphenyl) propionate octadecyl alcohol (Antioxidant 1076, Shaoguan Chengfeng Chemical Co., Ltd.);

[0041] Weigh the raw materials of each component according to the proportion, mix the raw materials of each component, heat and stir at 120±5℃, and gradually melt to form a uniformly mixed liquid;

[0042] The evenly mixed liquid is filtered and cooled; after cooling, a water-soluble 3D printing support material is obtained, which is filled into a wax bottle for later use.

[0043] Water dissolution rate test method: Pour the heated and molten support material into a cup-shaped silicone mold, measure 20g, and cool naturally to prepare a round cake-shaped support material. This material 20g is stirred at a constant temperature in 500g of hot water at a temperature of 45 degrees, and the time taken for the material to be completely dissolved is recorded.

[0044] Printing and cleaning model test: Put the wax bottle containing water-soluble 3D printing support material into the wax jet 3D printer (WaxJet 510, Zhejiang Flashcast Group Co., Ltd.) for printing test, use the commercially available Flashcast FFWJ1200 as the wax structure material to print the model structure, use the water-soluble 3D printing support material as the support, print a 20mm wide and 50mm long rectangular model, of which the top 1mm is the printed model of the structural material, and the bottom 10mm is the support material. After printing, use 1L of water to dissolve the support material under heating and stirring at 40℃. After most of the support material is dissolved, replace with new 1L of water, heat and stir at 40℃ to dissolve the remaining support material until the support material is completely dissolved. Get the printed model.

[0045] Material stability test: Take a sample of supporting material larger than 20g, place it in a 50ml open beaker, heat it in an oven at 130℃, and take it out every week to observe the changes in appearance.

[0046] Example 2

[0047] The difference from Example 1 is that the formula is: 60% of polyethylene glycol with a molecular weight of 5000 (PEG-5000 from Nantong Chenrun Chemical Co., Ltd.);

[0048] 30% of sodium polyacrylate PAA-Na-1800 with a molecular weight of 1800 (Zhongyan New Materials Co., Ltd.);

[0049] 9.5% polypropylene glycol with a molecular weight of 1000 (PPG1000 from Haian Petrochemical Company of Jiangsu Province);

[0050] 0.5% antioxidant distearyl thiodipropionate (Shaoguan Chengfeng Chemical Co., Ltd.)

[0051] The rest is the same as in Example 1. -

[0052] Example 3

[0053] The difference from Example 1 is that the formula is: 50% polyethylene glycol with a molecular weight of 800 (PEG-800 from Nantong Chenrun Chemical Co., Ltd.);

[0054] 37.5% sodium alginate (Guangdong Chuanliu Chemical Reagent);

[0055] 9.5% polypropylene glycol with a molecular weight of 800 (PPG800 from Jiangsu Haian Petrochemical);

[0056] 3% antioxidant 1076 (Shaoguan Chengfeng Chemical Co., Ltd.);

[0057] The rest is the same as in Example 1.

[0058] Example 4

[0059] The difference from Example 1 is that the formula is: 70% of polyethylene glycol with a molecular weight of 800 (PEG-800 from Nantong Chenrun Chemical Co., Ltd.);

[0060] 19.5% of sodium polyacrylate PAA-Na-1200 with a molecular weight of 1200 (Zhongyan New Materials Co., Ltd.);

[0061] 10% polypropylene glycol with a molecular weight of 800 (PPG800 from Jiangsu Haian Petrochemical);

[0062] 0.5% antioxidant BHT (Zhengzhou Mingxin Food Ingredients Co., Ltd.);

[0063] The rest is the same as in Example 1.

[0064] Example 5

[0065] The difference from Example 1 is that the formula is: 80% of polyethylene glycol with a molecular weight of 800 (PEG-800 from Nantong Chenrun Chemical Co., Ltd.);

[0066] 18.5% of sodium starch polyacrylate with a molecular weight of 10,000 (MAKIMOUSSE 7 from Guangzhou Qingyi Daily Chemical Co., Ltd.);

[0067] 1% polypropylene glycol with a molecular weight of 2000 (PPG2000 from Jiangsu Haian Petrochemical);

[0068] 0.5% antioxidant 1076 (Shaoguan Chengfeng Chemical Co., Ltd.);

[0069] The rest is the same as in Example 1.

[0070] Example 6

[0071] The difference from Example 1 is that the formula is: 60% of polyethylene glycol with a molecular weight of 20,000 (PEG-20000 from Nantong Chenrun Chemical Co., Ltd.);

[0072] 30% of sodium polyacrylate PAA-Na-1000 with a molecular weight of 1000 (Zhongyan New Materials Co., Ltd.);

[0073] 9.9% polypropylene glycol with a molecular weight of 1000 (PPG1000 from Haian Petrochemical Company of Jiangsu Province);

[0074] 0.1% antioxidant 1076 (Shaoguan Chengfeng Chemical Co., Ltd.);

[0075] The rest is the same as in Example 1.

[0076] Comparative Example 1

[0077] The difference from Example 1 is that the formula is: 70% of polyethylene glycol with a molecular weight of 800 (PEG-800 from Nantong Chenrun Chemical Co., Ltd.);

[0078] 19.5% water-based acrylic resin (Foshan Shangjin Chengzhan New Material Technology Co., Ltd.);

[0079] 10% polypropylene glycol with a molecular weight of 800 (PPG800 from Jiangsu Haian Petrochemical);

[0080] 0.5% antioxidant BHT (Zhengzhou Mingxin Food Ingredients Co., Ltd.);

[0081] The rest is the same as in Example 1.

[0082] Comparative Example 2

[0083] The difference from Example 1 is that the formula is: 80% nonanediol (developed by Shaanxi Shengyuantai Biotechnology);

[0084] 18.5% of sodium starch polyacrylate with a molecular weight of 10,000 (MAKIMOUSSE 7 from Guangzhou Qingyi Daily Chemical Co., Ltd.);

[0085] 1% polypropylene glycol with a molecular weight of 2000 (PPG2000 from Jiangsu Haian Petrochemical);

[0086] 0.5% antioxidant 1076 (Shaoguan Chengfeng Chemical Co., Ltd.);

[0087] The rest is the same as in Example 1.

[0088] Comparative Example 3

[0089] The difference from Example 1 is that the formula is: 60% PVA05-88 (Shengyu New Material Technology (Shanghai) Co., Ltd.), that is, PVA with a polymerization degree of about 500 and an alcoholysis degree of 88%;

[0090] 30% of sodium polyacrylate PAA-Na-1000 with a molecular weight of 1200 (Zhongyan New Materials Co., Ltd.);

[0091] 9.9% polypropylene glycol with a molecular weight of 800 (PPG800 from Haian Petrochemical Company of Jiangsu Province);

[0092] 0.1% antioxidant 1076 (Shaoguan Chengfeng Chemical Co., Ltd.);

[0093] The rest is the same as in Example 1.

[0094] Comparative Example 4

[0095] The difference from Example 1 is that the formula is: 50% polyethylene glycol with a molecular weight of 800 (PEG-800 from Nantong Chenrun Chemical Co., Ltd.);

[0096] 37.5% sodium alginate (Guangdong Chuanliu Chemical Reagent);

[0097] 9.5% polyvinylpyrrolidone (PVPK30 from Qingdao Hivision Biotechnology Co., Ltd.);

[0098] 3% antioxidant 1076 (Shaoguan Chengfeng Chemical Co., Ltd.);

[0099] The rest is the same as in Example 1.

[0100] Comparative Example 5

[0101] The difference from Example 1 is that the formula is: 60% of polyethylene glycol with a molecular weight of 1000 (PEG-1000 from Nantong Chenrun Chemical Co., Ltd.);

[0102] 30% of sodium polyacrylate PAA-Na-1000 with a molecular weight of 1200 (Zhongyan New Materials Co., Ltd.);

[0103] 9.9% PPG with a molecular weight of 400 (PPG400 from Haian Petrochemical Company of Jiangsu Province);

[0104] 0.1% antioxidant 1076 (Shaoguan Chengfeng Chemical Co., Ltd.);

[0105] The rest is the same as in Example 1.

[0106] Comparative Example 6

[0107] The difference from Example 1 is that the formula is: 50% of polyethylene glycol with a molecular weight of 1000 (PEG-1000 from Nantong Chenrun Chemical Co., Ltd.);

[0108] 48% of sodium polyacrylate PAA-Na-1000 with a molecular weight of 1000 (Zhongyan New Materials Co., Ltd.);

[0109] 1.5% PPG with a molecular weight of 800 (PPG800 from Haian Petrochemical Company of Jiangsu Province);

[0110] 0.5% antioxidant 1076 (Shaoguan Chengfeng Chemical Co., Ltd.);

[0111] The rest is the same as in Example 1.

[0112] The water dissolution rate test method, printing and cleaning model test, and printing and cleaning model test were performed on Examples 1-6 and Comparative Examples 1-6. The material stability results are shown in Figure 1 .

[0113] The test results are shown in the following table:

[0114]

[0115] It can be seen from the above performance comparison table that in Example 1 and Example 2, the support dissolution rate, model cleaning effect, material heat resistance and other aspects are relatively good; in Example 3 and Example 5, the support dissolution rate is relatively fast, and the model cleaning effect is relatively good, but the material heat resistance is insufficient, and the color change and yellowing after heating aging are serious, almost brown, which can meet the basic use requirements, but the service life of the material is affected to a certain extent; in Example 4 and Example 6, the support dissolution rate is relatively fast, and the model cleaning effect is relatively good, but the material heat resistance is slightly insufficient, and it is obviously yellowed after heating aging.

[0116] Compared with Example 4, the most significant change in Comparative Example 1 is that water-based acrylic resin is used instead. Generally, acrylic resin is insoluble in water. Water-based acrylic resin is usually modified with hydroxyl groups to obtain water solubility. However, the water solubility of the obtained water-based acrylic resin is not so good, resulting in a significantly slower dissolution rate of the support material obtained in Comparative Example 1 than in Example 1. Compared with Example 5, Comparative Example 2 uses nonanediol instead. On the one hand, nonanediol is a small molecule. On the other hand, nonanediol has a high freezing point. During the printing process, the support material cools down quickly, resulting in insufficient strength of the obtained support material. The support material collapses during the printing process, such as Figure 2 As shown, the printing cannot be actually completed. Compared with Example 1, the biggest change in Comparative Example 3 is the use of PVA, which has a much slower dissolution speed and takes more than 40 minutes to dissolve. It takes 30 minutes to completely dissolve after the water temperature is raised to 70°C. The printed model material cannot be washed with wax at 70 degrees. The wax washing time is very long at low temperatures. Long-term wax washing causes a serious decrease in the strength of the model. Compared with Example 3, Comparative Example 4 uses PVP instead of PPG, but the obtained model turns white after washing, and the wax washing speed is slower than that of Example 3. The viscosity of PVP is very large after it is dissolved in water, which affects the fluidity of the solution and causes the dissolution speed to slow down. Compared with Example 1, Comparative Example 5 uses PPG400. PPG400 can be dissolved in water, and it has no function of separating the support and structural materials during wax washing. The wax washing speed is slightly slower, and the model after wax washing will have a partial whitening phenomenon, such as Figure 3 Comparative Example 6 uses a large proportion of sodium polyacrylate, which causes the sodium polyacrylate to absorb water and swell severely during the process of water dissolving the support material, thus damaging the model details.

[0117] The above are only preferred embodiments of the present invention. The protection scope of the present invention shall be based on the scope defined by the claims. Several improvements and modifications made by those skilled in the art without departing from the spirit and scope of the present invention should also be regarded as the protection scope of the present invention.

Claims

1. A water-soluble 3D printing support material, suitable for printing 3D objects in combination with a waxy structural material, characterized in that: The water-soluble 3D printing support material includes the following components by weight percentage:

2. The water-soluble 3D printing support material according to claim 1, characterized in that: The molecular weight of the polyethylene glycol is 800-20000.

3. The water-soluble 3D printing support material according to claim 1, characterized in that: The molecular weight of the polyethylene glycol is 1000-8000.

4. The water-soluble 3D printing support material according to claim 1, characterized in that: The molecular weight of the polypropylene glycol is 800-2000.

5. The water-soluble 3D printing support material according to claim 1, characterized in that: The highly water-absorbent resin comprises at least one of alginic acid, alginate, starch acrylate polymer, polyacrylic acid, and polyacrylate.

6. The water-soluble 3D printing support material according to claim 1, characterized in that: The antioxidant comprises at least one of β-(3.5-di-tert-butyl-4-hydroxyphenyl) propionate, tris(2,4-tert-butylphenyl) phosphite, distearyl thiodipropionate and phenolic 2,6-di-tert-butyl-p-cresol.

7. The water-soluble 3D printing support material according to claim 1, characterized in that: The super absorbent resin includes sodium polyacrylate with a molecular weight of 1000-10000.

8. The water-soluble 3D printing support material according to claim 1, characterized in that: The antioxidant is β-(3.5-di-tert-butyl-4-hydroxyphenyl) propionate.

9. A method for preparing a water-soluble 3D printing support material according to any one of claims 1 to 8, characterized in that: The preparation method comprises the following steps: Weigh the raw materials of each component according to the proportion, mix the raw materials of each component, heat and stir at 70-150°C, and gradually melt to form a uniformly mixed liquid; The mixed liquid is filtered and cooled.

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