Environment-friendly degradable fast water-soluble 3D printing support material and preparation method thereof

Abstract

The present application belongs to the field of 3D printing material preparation, and provides an environment-friendly degradable fast water-soluble 3D printing support material and a preparation method thereof. The purpose is to solve the problems of low solubility and difficult processing of the existing 3D printing support wire. The environment-friendly degradable fast water-soluble 3D printing support material comprises lignin sulfonate, polyvinyl alcohol, lubricant, heat stabilizer and lithium chloride. The preparation method is as follows: the raw materials are mixed, and then granulated by double-screw extrusion; then the blended material is added into a single-screw extruder for extrusion and wire drawing to obtain the fast water-soluble 3D printing support wire. The material has excellent room-temperature water-solubility, high strength, solves the problems of difficult processing and room-temperature insolubility of PVA, and after water-solubility, the material becomes a uniform solution, solving the problem of difficult processing of the support material.

Description

TECHNICAL FIELD

[0001] The present application belongs to the field of preparation of 3D printing materials, and particularly relates to an environmentally friendly and degradable fast water-soluble 3D printing support material and a preparation method thereof. BACKGROUND

[0002] The information disclosed in this Background section is for the purpose of increasing the understanding of the background of the present application and therefore it not to be taken as an acknowledgement or any form of suggestion that it forms prior art with respect to the present application.

[0003] 3D printing technology is a method of layer-by-layer accumulation, which can realize the multi-scale design and regulation of materials, and can manufacture products with complex structures to meet different structural and application requirements. However, when printing products with complex shapes, a large amount of support structures need to be printed, and thus the products face the following technical problems: ① it is difficult to remove the support structures of the same printing material, and mechanical removal can easily damage the product quality or leave printing marks; ② the organic solvent support material has problems such as high toxicity and pollution. Therefore, the development of water-soluble 3D printing support materials is the key and the best solution to solve the above problems. Currently, the materials commonly used to prepare support wires mainly include acrylic resin and polyvinyl alcohol. Patent US6790403B1 discloses a 3D printing water-soluble support wire using acrylic resin as the main raw material. The material can be dissolved in an aqueous alkali solution and has high strength. However, the material has poor printing performance, poor water solubility at room temperature, and long dissolution time. Patent WO2015175682A1 discloses introducing styrene monomers into acrylic monomers for polymerization to obtain a 3D printing water-soluble support wire, but the same problem of poor water solubility exists.

[0004] Polyvinyl alcohol is a good water-absorbing material, which can be reused and biodegraded, and has good mechanical strength and ecological value. However, polyvinyl alcohol has a high crystallinity, a large number of intramolecular and intermolecular hydrogen bonds, and a complex molecular chain structure formed by the interaction and interweaving of molecules, resulting in a processing temperature of polyvinyl alcohol higher than its thermal decomposition temperature, so that polyvinyl alcohol is generally decomposed before melting, and has poor processing performance. In addition, polyvinyl alcohol has a large number of carboxylic acid functional groups, which will decompose to produce acidic gas during processing, further promoting the carbonization of polyvinyl alcohol. Polyvinyl alcohol also has the problem of poor water solubility. After the polyvinyl alcohol support material is dissolved in water, it will produce a sticky and turbid state, making it difficult to clean the corners and holes.

[0005] Patent CN107189297A discloses a water-soluble degradable material, a preparation method and a 3D printing support, by adding polyvinyl alcohol with high alcoholysis degree to reduce the carboxylic acid group in the molecular chain, and using glycerol for plasticizing, thereby slowing down the thermal decomposition in the processing process. However, by reducing the carboxylic acid group, the interweaving effect between polyvinyl alcohol molecules and the hydrogen bond between molecular chains cannot be destroyed, and the plasticizing effect cannot be truly achieved. In addition, polyvinyl alcohol with high alcoholysis degree is high in price, which is not conducive to large-scale industrial application. Therefore, the method can alleviate the thermal degradation of polyvinyl alcohol in the processing process, but cannot change the molecular structure and spatial structure of polyvinyl alcohol, and it is difficult to realize water-solubility of the support material at room temperature. SUMMARY

[0006] To solve the above problems, the present application provides a 3D printing support material with normal temperature fast water-solubility and a preparation method thereof. The 3D printing support material has the advantages of fast water-solubility, low dissolution temperature, low solution viscosity after dissolution, good support effect, recyclability, low cost, environmental protection and non-toxicity.

[0007] To achieve the above-mentioned purposes, the present application adopts the following technical solutions:

[0008] In a first aspect of the present application, an environmentally friendly degradable fast water-soluble 3D printing support material is provided, which is composed of the following raw materials by weight: lignin sulfonate 10-60 parts, polyvinyl alcohol 40-90 parts, lubricant 0-10 parts, thermal stabilizer 0-10 parts, and lithium chloride 1-10 parts.

[0009] In some embodiments, the alcoholysis degree of the polyvinyl alcohol is 78%-98%, and the polymerization degree of the polyvinyl alcohol is 1700-2400.

[0010] In some embodiments, the lubricant is selected from at least one of glycerol, water, paraffin, stearic acid, zinc stearate, and calcium stearate.

[0011] In some embodiments, the thermal stabilizer is selected from at least one of dibutyltin dilaurate, dioctyltin dilaurate, dialkyltin maleate, dioctyltin maleate, and dioctyltin bis(mercaptoacetate isooctyl ester).

[0012] In a second aspect of the present application, a preparation method of an environmentally friendly degradable fast water-soluble 3D printing support material is provided, which comprises:

[0013] The lignin sulfonate is heat treated to remove small molecule volatile and degradable substances in the lignin sulfonate;

[0014] The heat-treated lignin sulfonate, polyvinyl alcohol, lubricant, thermal stabilizer and lithium chloride are uniformly mixed to obtain a mixture.

[0015] The mixture is granulated by twin-screw extrusion to obtain a blend;

[0016] The blend is added to a single-screw extruder for extrusion and drawing to obtain the fast water-soluble 3D printing support wire.

[0017] In some embodiments, the heat treatment is performed at 100-200℃ for 0.5-48h.

[0018] In some embodiments, the extrusion temperature for the twin-screw extrusion granulation is 170-240℃, and the screw rotation speed is 30-200rpm.

[0019] In some embodiments, the extrusion temperature for the extrusion and drawing is 170-240℃, and the screw rotation speed is 20-150rpm.

[0020] More specifically, the method comprises:

[0021] 1) heat treatment: the lignin sulfonate is treated at 100-200℃ for 0.5-48h to remove small molecular volatile and degradable substances in the lignin sulfonate;

[0022] 2) the lignin sulfonate, polyvinyl alcohol, lubricant, heat stabilizer and lithium chloride in step 1) are mixed uniformly, wherein the mass fraction ratio of the lignin sulfonate, polyvinyl alcohol, lubricant, heat stabilizer and lithium chloride is 10-60:40-90:0-10:0-10:1-10;

[0023] 3) the mixture in step 2) is granulated by twin-screw extrusion, the extrusion temperature is 170-240℃, and the screw rotation speed is 30-200rpm to obtain a blend;

[0024] 4) the blend obtained in step 3) is added to a single-screw extruder for extrusion and drawing to obtain the fast water-soluble 3D printing support wire, the extrusion temperature is 170-240℃, and the screw rotation speed is 20-150rpm.

[0025] In a third aspect, the application provides the use of the support material described above in 3D printing.

[0026] Advantages of the application

[0027] (1) The lignosulfonate adopted in the present application contains a large amount of sulfonic acid groups, has very strong water absorption, and can improve the water solubility of the 3D printing wire, so that it can be quickly dissolved at room temperature. The lignosulfonate contains a large amount of hydroxyl groups, which can undergo esterification reaction with the carboxylic acid functional groups on the polyvinyl alcohol, shielding the carboxylic acid on the polyvinyl alcohol, thereby slowing down the degradation of the polyvinyl alcohol during processing. In addition, intermolecular hydrogen bonds can also be formed between lignosulfonate and polyvinyl alcohol molecules. The existence of these ester functional groups and hydrogen bonds destroys the interweaving action between polyvinyl alcohol molecular chains, reducing the crystallinity of polyvinyl alcohol. Lignosulfonate plays a certain plasticizing role, thereby improving the processing performance of polyvinyl alcohol. At the same time, lignin is a waste product of the papermaking industry, and its price is low. The use of lignosulfonate to replace part of the polyvinyl alcohol can reduce the cost of the product and promote the efficient and high-value utilization of lignin. Lithium chloride has excellent water absorption performance and can improve the water solubility of the wire. In summary, compared with the existing polyvinyl alcohol or acrylic water-soluble 3D printing support wire, the environmentally friendly and degradable fast water-soluble 3D printing support material of the present application has the advantages of good water solubility, low dissolution temperature, good processing performance, low cost and ecological environmental protection.

[0028] (2) The preparation method of the present application is simple, practical and easy to popularize. BRIEF DESCRIPTION OF DRAWINGS

[0029] The drawings accompanying the specification of the present application serve to provide a further understanding of the present application, and the exemplary embodiments of the present application and the description thereof serve to explain the present application, and do not constitute an improper limitation on the present application.

[0030] Figure 1 The infrared spectrum of the water-soluble 3D printing support wire prepared in Examples 1-3 and Comparative Example 1 of the present application.

[0031] Figure 2 The elongation at break of the water-soluble 3D printing support wire prepared in Examples 1-3 and Comparative Example 1 of the present application.

[0032] Figure 3 The water solubility test chart of the water-soluble 3D printing support wire prepared in Examples 1-3 of the present application.

[0033] Figure 4 The water solubility test chart of the water-soluble 3D printing support wire prepared in Comparative Example 1 of the present application.

[0034] Figure 5 The appearance morphology chart of the water-soluble 3D printing support wire prepared in Examples 1 and Comparative Example 1 of the present application. DETAILED DESCRIPTION

[0035] It should be noted that the following detailed description is exemplary in nature and is intended to provide further description of the application. Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs.

[0036] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs. The terminology used in the description herein is for describing particular embodiments only and is not intended to be limiting of the application. As used herein, the term "and / or" includes any and all combinations of one or more of the associated listed items.

[0037] Specific embodiment one: an environmentally friendly degradable fast water-soluble 3D printing support material prepared from the following raw materials: lignin sulfonate, polyvinyl alcohol, lubricant, thermal stabilizer, lithium chloride, wherein the mass fraction ratio of lignin sulfonate, polyvinyl alcohol, lubricant, thermal stabilizer and lithium chloride is 10-60:40-90:0-10:0-10:1-10.

[0038] Specific embodiment two: different from specific embodiment one, the lubricant is a mixture of one or more of glycerol, water, paraffin, stearic acid, zinc stearate, calcium stearate; the thermal stabilizer is a mixture of one or more of dibutyltin dilaurate, dioctyltin dilaurate, dialkyltin maleate, dioctyltin maleate, dioctyltin bis(mercaptoacetate isooctyl ester).

[0039] Specific embodiment three: a preparation method of an environmentally friendly degradable fast water-soluble 3D printing support material as described in specific embodiment one is carried out according to the following steps:

[0040] 1) heat treatment: lignin sulfonate is treated at 100-200°C for 0.5-48h to remove small molecule volatile and degradable substances in lignin sulfonate;

[0041] 2) mix lignin sulfonate, polyvinyl alcohol, lubricant, thermal stabilizer and lithium chloride in step 1) uniformly, wherein the mass fraction ratio of lignin sulfonate, polyvinyl alcohol, lubricant, thermal stabilizer and lithium chloride is 10-60:40-90:0-10:0-10:1-10;

[0042] 3) granulate the mixture in step 2) by double screw extrusion, the extrusion temperature is 170-240°C, the screw rotation speed is 30-200rpm, and the blended material is obtained;

[0043] 4) The blended material obtained in step 3 is added into a single screw extruder to be extruded into a fast water-soluble 3D printing support wire, the extrusion temperature is 170-240℃, and the screw rotation speed is 20-150 rpm.

[0044] The application will be further described in detail below with reference to specific examples, which are intended to explain but not to limit the application.

[0045] Example 1

[0046] The lignosulfonate is treated at 120℃ for 3h, then 10 parts by mass of the treated lignosulfonate, 85 parts by mass of polyvinyl alcohol and 5 parts by mass of lithium chloride are thoroughly mixed to obtain a premix. The premix is then melt-extruded and granulated by a twin-screw extruder to obtain a masterbatch, the extrusion temperature is 175℃, 185℃, 190℃, 190℃, 200℃ and 200℃ from the feeding section to the die head, and the screw rotation speed is 50 rpm. Then the masterbatch is extruded into a wire by a single screw extruder, the extrusion temperature is 205℃, 200℃ from the feeding section to the die head, and the extrusion rate is 20 rpm. The polyvinyl alcohol has a polymerization degree of 1700 and an alcoholysis degree of 88%.

[0047] Example 2

[0048] The lignosulfonate is treated at 120℃ for 3h, then 20 parts by mass of the treated lignosulfonate, 75 parts by mass of polyvinyl alcohol and 5 parts by mass of lithium chloride are thoroughly mixed to obtain a premix. The premix is then melt-extruded and granulated by a twin-screw extruder to obtain a masterbatch, the extrusion temperature is 175℃, 185℃, 190℃, 190℃, 200℃ and 200℃ from the feeding section to the die head, and the screw rotation speed is 50 rpm. Then the masterbatch is extruded into a wire by a single screw extruder, the extrusion temperature is 205℃, 200℃ from the feeding section to the die head, and the extrusion rate is 20 rpm. The polyvinyl alcohol has a polymerization degree of 1700 and an alcoholysis degree of 88%.

[0049] Example 3

[0050] The lignosulfonate is treated at 120℃ for 3h, then 30 parts by mass of the treated lignosulfonate, 65 parts by mass of polyvinyl alcohol and 5 parts by mass of lithium chloride are thoroughly mixed to obtain a premix. The premix is then melt-extruded and granulated by a twin-screw extruder to obtain a masterbatch, the extrusion temperature is 175℃, 185℃, 190℃, 190℃, 200℃ and 200℃ from the feeding section to the die head, and the screw rotation speed is 50 rpm. Then the masterbatch is extruded into a wire by a single screw extruder, the extrusion temperature is 205℃, 200℃ from the feeding section to the die head, and the extrusion rate is 20 rpm. The polyvinyl alcohol has a polymerization degree of 1700 and an alcoholysis degree of 88%.

[0051] Example 4

[0052] The lignosulfonate was treated at 120°C for 3h, then 10 parts by mass of the treated lignosulfonate, 80 parts by mass of polyvinyl alcohol, 5 parts by mass of glycerol, and 5 parts by mass of lithium chloride were thoroughly mixed to obtain a premix. The premix was then melt-extruded and granulated by a twin-screw extruder to obtain a masterbatch, with the extrusion temperature being 175°C, 185°C, 190°C, 190°C, 200°C, and 200°C from the feeding section to the head, and the screw rotation speed being 50 rpm. Then the masterbatch was extruded into a wire by a single-screw extruder, with the extrusion temperature being 205°C, 200°C from the feeding section to the head, and the extrusion rate being 20 rpm. The polyvinyl alcohol had a degree of polymerization of 1700 and an alcoholysis degree of 88%.

[0053] Example 5

[0054] The lignosulfonate was treated at 120°C for 3h, then 10 parts by mass of the treated lignosulfonate, 75 parts by mass of polyvinyl alcohol, 10 parts by mass of glycerol, and 5 parts by mass of lithium chloride were thoroughly mixed to obtain a premix. The premix was then melt-extruded and granulated by a twin-screw extruder to obtain a masterbatch, with the extrusion temperature being 175°C, 185°C, 190°C, 190°C, 200°C, and 200°C from the feeding section to the head, and the screw rotation speed being 50 rpm. Then the masterbatch was extruded into a wire by a single-screw extruder, with the extrusion temperature being 205°C, 200°C from the feeding section to the head, and the extrusion rate being 20 rpm. The polyvinyl alcohol had a degree of polymerization of 1700 and an alcoholysis degree of 88%.

[0055] Example 6

[0056] The lignosulfonate was treated at 120°C for 3h, then 10 parts by mass of the treated lignosulfonate, 80 parts by mass of polyvinyl alcohol, 5 parts by mass of zinc stearate, and 5 parts by mass of lithium chloride were thoroughly mixed to obtain a premix. The premix was then melt-extruded and granulated by a twin-screw extruder to obtain a masterbatch, with the extrusion temperature being 175°C, 185°C, 190°C, 190°C, 200°C, and 200°C from the feeding section to the head, and the screw rotation speed being 50 rpm. Then the masterbatch was extruded into a wire by a single-screw extruder, with the extrusion temperature being 205°C, 200°C from the feeding section to the head, and the extrusion rate being 20 rpm. The polyvinyl alcohol had a degree of polymerization of 1700 and an alcoholysis degree of 88%.

[0057] Comparative Example 1

[0058] 100 parts by mass of polyvinyl alcohol (pure polyvinyl alcohol) was melt-extruded and pelletized by a twin-screw extruder to obtain a master batch, the extrusion temperature was 175℃, 185℃, 190℃, 190℃, 200℃ and 200℃ from the feeding section to the die head, and the screw rotation speed was 50 rpm. Then it was extruded into a wire by a single-screw extruder, the extrusion temperature was 205℃, 200℃ from the feeding section to the die head, and the extrusion rate was 20 rpm. The degree of polymerization of polyvinyl alcohol was 1700, and the alcoholysis degree was 88%.

[0059] The difference from Example 1 is that the raw material in Comparative Example 1 is only polyvinyl alcohol, and other processing conditions are completely consistent.

[0060] Experimental Example 1

[0061] The performance of the water-soluble 3D printing support wire prepared in the examples and comparative examples was tested, and the results were as follows:

[0062] As shown in Figure 1 , compared with Comparative Example 1, the characteristic absorption vibration peak of lignin can be observed at 1600 cm -1 in Example 1-3 after adding lignin.

[0063] As shown in Figure 2 , compared with Comparative Example 1, the elongation at break of Example 1-3 after adding lignin is obviously improved, because lignin sulfonate crosslinks with polyvinyl alcohol to form a network structure, resulting in increased toughness of the composite material.

[0064] As shown in Figure 3 , Figure 4 , the digital photo of the water-soluble 3D printing support wire prepared in Example 1-3 after soaking in water at room temperature for 30 min shows that the composite material is almost completely dissolved in the aqueous solution, and there is no obvious boundary. The digital photo of Comparative Example 1 after soaking in water at room temperature for 30 min shows that the sample only swells by absorbing water and does not dissolve in the aqueous solution, and there is an obvious boundary.

[0065] As can be observed: Figure 5 , compared with Comparative Example 1, the wire surface becomes smooth after adding lignin in Example 1, and the processability is improved under the same processing conditions.

[0066] The above only describes the preferred embodiments of the present application and is not intended to limit the present application. For those skilled in the art, the present application can have various modifications and changes. Any modification, equivalent replacement, improvement, etc. made within the spirit and principles of the present application shall be included in the protection scope of the present application.

Claims

1. An environmentally friendly, biodegradable, fast water-soluble 3D printing support material, characterized in that, The raw materials are composed of 10-60 parts of lignosulfonate, 40-90 parts of polyvinyl alcohol, 0-10 parts of lubricant, 0-10 parts of heat stabilizer, and 1-10 parts of lithium chloride; The preparation method of the environment-friendly and degradable rapid water-soluble 3D printing support material comprises the following steps: The lignosulfonate is subjected to heat treatment to remove small-molecule volatile and degradable substances in the lignosulfonate; The heat-treated lignosulfonate, polyvinyl alcohol, lubricant, heat stabilizer and lithium chloride are uniformly mixed to obtain a mixture; The mixture is subjected to double-screw extrusion granulation to obtain a blended material; The blended material is added into a single-screw extruder for extrusion and drawing to obtain a rapid water-soluble 3D printing support wire.

2. The environmentally friendly, biodegradable, fast water-soluble 3D printing support material according to claim 1, wherein The alcoholysis degree of the polyvinyl alcohol is 78-98%. Alternatively, the polymerization degree of the polyvinyl alcohol is 1700-2400.

3. The environmentally friendly, biodegradable, fast water soluble 3D printing support material according to claim 1, wherein, The lubricant is at least one selected from glycerol, water, paraffin, stearic acid, zinc stearate and calcium stearate.

4. The environmentally friendly, degradable, fast water-soluble 3D printing support material according to claim 1, wherein The heat stabilizer is at least one selected from dibutyltin dilaurate, dioctyltin dilaurate, dialkyltin maleate, dioctyltin maleate and dioctyltin bis(mercaptoacetic acid isooctyl ester).

5. The environmentally friendly, biodegradable, fast water soluble 3D printing support material as claimed in claim 1, wherein, The heat treatment is performed at 100-200℃ for 0.5-48h.

6. The environmentally friendly, degradable, fast water-soluble 3D printing support material according to claim 1, wherein The extrusion temperature of the double-screw extrusion granulation is 170-240℃, and the screw rotation speed is 30-200rpm.

7. The environmentally friendly, degradable, fast water-soluble 3D printing support material according to claim 1, wherein The extrusion temperature of the extrusion and drawing is 170-240℃, and the screw rotation speed is 20-150rpm.

8. Application of the environment-friendly and degradable rapid water-soluble 3D printing support material in 3D printing according to any one of claims 1-7.

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