Environment-friendly degradable rapid water-soluble 3D printing supporting material and preparation method thereof

Abstract

The invention belongs to the field of preparation of 3D printing materials, and provides an environment-friendly degradable rapid water-soluble 3D printing supporting material and a preparation method thereof. The purpose is to solve the problems that an existing 3D printing supporting wire is low in solubility and difficult to process. The environment-friendly degradable rapid water-soluble 3D printing supporting material is prepared from lignosulfonate, polyvinyl alcohol, a lubricating agent, a heat stabilizer and lithium chloride. The preparation method comprises the following steps: mixing the raw materials, and carrying out twin-screw extrusion granulation; and then adding the co-mixture into a single-screw extruder for extrusion and wire drawing to obtain the rapid water-soluble 3D printing support wire. The material has excellent room-temperature water solubility and relatively high strength, and solves the problems of difficulty in processing and insolubility at room temperature of PVA (Polyvinyl Alcohol); the material is a uniform solution after being dissolved in water, and the problem that the supporting material is difficult to treat is solved.

Description

Technical Field

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

[0002] The information disclosed in this background technology section is only intended to enhance the understanding of the overall background of the invention, and should not necessarily be regarded as an admission or any form of suggestion that the information constitutes the prior art already known to a person skilled in the art.

[0003] 3D printing technology can achieve multi-scale design and regulation of materials through a layer-by-layer stacking method, and can produce products with complex structures to meet different structural and application requirements. However, when printing complex-shaped products, a large number of support structures need to be printed. In this way, the product faces the following technical difficulties: ① It is difficult to remove the support structure of the same printing material, and mechanical removal is likely to damage the product quality or leave printing traces; ② Organic solvent support materials have problems such as high toxicity and pollution. Therefore, the development of water-soluble 3D printing support materials is the key and best solution to solve the above problems. At present, the materials commonly used to prepare support wires are mainly acrylic resin and polyvinyl alcohol. Patent US6790403B1 discloses a 3D printing water-soluble support wire with acrylic resin as the main raw material. The material can be dissolved in an alkaline aqueous solution and has high strength. However, the material has poor printing performance, poor water solubility at room temperature, and a long dissolution time. Patent WO2015175682A1 discloses that styrene monomers are introduced into acrylic monomers for polymerization to obtain 3D printing water-soluble support wires, but there is also a problem of poor water solubility.

[0004] Polyvinyl alcohol is a good water-absorbing material that can be reused and biodegraded, and has good mechanical strength and ecological value. However, polyvinyl alcohol has a high degree of crystallinity, a large number of hydrogen bonds within and between molecules, and the molecules interact and interweave to form an intricate molecular chain structure, which causes the processing temperature of polyvinyl alcohol to be higher than its thermal decomposition temperature, so that polyvinyl alcohol generally decomposes before melting, and the processing performance is poor. In addition, there are more carboxylic acid functional groups on polyvinyl alcohol, which will decompose and produce acidic gases during processing, further promoting the carbonization of polyvinyl alcohol. Polyvinyl alcohol also has the problem of poor water solubility. After being dissolved in water, the polyvinyl alcohol support material will produce a sticky and turbid state, making it difficult to clean corners and holes. This is because polyvinyl alcohol has poor water solubility at room temperature and can only swell but not dissolve.

[0005] Patent CN107189297A discloses a water-soluble degradable material, a preparation method and a 3D printing support, which reduces the carboxylic acid groups in the molecular chain by adding polyvinyl alcohol with a high alcoholysis degree, and uses propylene glycol for plasticization, thereby slowing down the thermal decomposition during processing. However, reducing the carboxylic acid groups cannot destroy the interweaving effect between polyvinyl alcohol molecules and reduce the hydrogen bonding between molecular chains, and cannot really play a plasticizing role. In addition, polyvinyl alcohol with a high alcoholysis degree is relatively expensive, which is not conducive to large-scale industrial applications. Therefore, this method can alleviate the thermal degradation of polyvinyl alcohol during processing, but it cannot change the molecular structure and spatial structure of polyvinyl alcohol, and it is difficult to achieve water dissolution of the support material at room temperature. Summary of the invention

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

[0007] In order to achieve the above object, the present invention adopts the following technical solution:

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

[0009] In some embodiments, the alcoholysis degree of the polyvinyl alcohol is 78% to 98%, and the polymerization degree of the polyvinyl alcohol is 1700 to 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 heat stabilizer is selected from at least one of dibutyltin dilaurate, dioctyltin dilaurate, dialkyltin maleate, dioctyltin maleate, and dioctyltin bis(isooctyl mercaptoacetate).

[0012] The second aspect of the present invention provides a method for preparing an environmentally friendly, degradable, fast-water-soluble 3D printing support material, comprising:

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

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

[0015] The mixture is extruded and granulated by a twin-screw extruder to obtain a blended material;

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

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

[0018] In some embodiments, the extrusion temperature of the twin-screw extrusion granulation is 170-240° C., and the screw speed is 30-200 rpm.

[0019] In some embodiments, the extrusion temperature of the extrusion wire drawing is 170-240° C., and the screw speed is 20-150 rpm.

[0020] More specifically, they include:

[0021] 1) Heat treatment: treating the lignin sulfonate at 100-200°C for 0.5-48h to remove small molecule volatile and degradable substances in the lignin sulfonate;

[0022] 2) mixing the lignin sulfonate, polyvinyl alcohol, lubricant, heat stabilizer and lithium chloride in step 1) 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) extruding the mixture in step 2) through a twin-screw extruder to obtain a blended material at a temperature of 170 to 240° C. and a screw speed of 30 to 200 rpm;

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

[0025] The third aspect of the present invention provides the use of the above-mentioned support material in 3D printing.

[0026] Beneficial Effects of the Invention

[0027] (1) The lignin sulfonate used in the present invention contains a large number of sulfonic acid groups and has very strong water absorption, which can improve the water solubility of 3D printing wires and enable them to dissolve quickly at room temperature. Lignin sulfonate contains a large number of hydroxyl groups, which can undergo esterification reaction with the carboxylic acid functional groups on polyvinyl alcohol, shielding the carboxylic acid on polyvinyl alcohol, thereby slowing down the degradation of polyvinyl alcohol during processing. In addition, intermolecular hydrogen bonds can be formed between lignin sulfonate and polyvinyl alcohol molecules. The presence of these ester functional groups and hydrogen bonds destroys the interweaving effect between polyvinyl alcohol molecular chains and reduces the crystallinity of polyvinyl alcohol. Lignin sulfonate plays a certain plasticizing role, thereby improving the processing properties of polyvinyl alcohol. At the same time, lignin is a waste product of the papermaking industry and is cheap. Using lignin sulfonate to replace part of polyvinyl alcohol can reduce product costs and promote efficient and high-value utilization of lignin. Lithium chloride has excellent water absorption properties and can improve the water solubility of wires. In summary, compared with the existing polyvinyl alcohol or acrylic water-soluble 3D printing support wires, the environmentally friendly and degradable fast water-soluble 3D printing support material of the present invention 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 invention is simple, practical and easy to promote. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] The accompanying drawings constituting a part of the present invention are used to provide a further understanding of the present invention, and the exemplary embodiments of the present invention and their description are used to explain the present invention and do not constitute improper limitations on the present invention.

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

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

[0032] Figure 3 This is a water solubility test diagram of the water-soluble 3D printing support wire prepared in Examples 1-3 of the present invention.

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

[0034] Figure 5 The following are appearance morphology images of the water-soluble 3D printing support wires prepared in Example 1 and Comparative Example 1 of the present invention. DETAILED DESCRIPTION

[0035] It should be noted that the following detailed descriptions are exemplary and are intended to provide further explanation of the present invention. Unless otherwise specified, all technical and scientific terms used in the present invention have the same meanings as those commonly understood by those skilled in the art to which the present invention belongs.

[0036] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as those generally understood by those skilled in the art of the present invention. The terms used herein in the specification of the present invention are only for the purpose of describing specific embodiments and are not intended to limit the present invention. The term "and / or" used herein includes any and all combinations of one or more related listed items.

[0037] Specific implementation method 1: An environmentally friendly, degradable, fast-water-soluble 3D printing support material in this implementation method is mainly prepared from the following raw materials: lignin sulfonate, polyvinyl alcohol, lubricant, thermal stabilizer, and 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 2: This embodiment is different from specific embodiment 1 in that the lubricant is one or a mixture of glycerol, water, paraffin, stearic acid, zinc stearate, and calcium stearate; the heat stabilizer is one or a mixture of dibutyltin dilaurate, dioctyltin dilaurate, dialkyltin maleate, dioctyltin maleate, and dioctyltin di(isooctyl thioglycolate).

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

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

[0041] 2) mixing the lignin sulfonate, polyvinyl alcohol, lubricant, heat stabilizer and lithium chloride in step 1) 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;

[0042] 3) extruding the mixture in step 2) through a twin-screw extruder to obtain a blended material at a temperature of 170 to 240° C. and a screw speed of 30 to 200 rpm;

[0043] 4) The blend obtained in step 3 is added to a single screw extruder for extrusion and drawing to obtain a fast water-soluble 3D printing support wire, the extrusion temperature is 170-240° C., and the screw speed is 20-150 rpm.

[0044] The present invention will be further described in detail below in conjunction with specific embodiments. It should be noted that the specific embodiments are intended to explain the present invention rather than to limit it.

[0045] Example 1

[0046] The lignin sulfonate was treated at 120°C for 3h, and then 10 parts by mass of the treated lignin sulfonate, 85 parts by mass of polyvinyl alcohol and 5 parts by mass of lithium chloride were fully mixed to obtain a premix. The premix was then melt-extruded and granulated by a twin-screw extruder to obtain a masterbatch. The extrusion temperatures from the feed section to the die were 175°C, 185°C, 190°C, 190°C, 200°C and 200°C, respectively, and the screw speed was 50rpm. Then, a single screw was used to extrude the wire. The extrusion temperatures from the feed section to the die were 205°C and 200°C, respectively, and the extrusion rate was 20rpm. The degree of polymerization of polyvinyl alcohol was 1700, and the degree of alcoholysis was 88%.

[0047] Example 2

[0048] The lignin sulfonate was treated at 120°C for 3h, and then 20 parts by mass of the treated lignin sulfonate, 75 parts by mass of polyvinyl alcohol and 5 parts by mass of lithium chloride were fully mixed to obtain a premix. The premix was then melt-extruded and granulated by a twin-screw extruder to obtain a masterbatch. The extrusion temperatures from the feed section to the die were 175°C, 185°C, 190°C, 190°C, 200°C and 200°C, respectively, and the screw speed was 50rpm. Then, a single screw was used to extrude the wire. The extrusion temperatures from the feed section to the die were 205°C and 200°C, respectively, and the extrusion rate was 20rpm. The degree of polymerization of polyvinyl alcohol was 1700, and the degree of alcoholysis was 88%.

[0049] Example 3

[0050] The lignin sulfonate was treated at 120°C for 3h, and then 30 parts by mass of the treated lignin sulfonate, 65 parts by mass of polyvinyl alcohol and 5 parts by mass of lithium chloride were fully mixed to obtain a premix. The premix was then melt-extruded and granulated by a twin-screw extruder to obtain a masterbatch. The extrusion temperatures from the feed section to the die were 175°C, 185°C, 190°C, 190°C, 200°C and 200°C, respectively, and the screw speed was 50rpm. Then, a single screw was used to extrude the wire. The extrusion temperatures from the feed section to the die were 205°C and 200°C, respectively, and the extrusion rate was 20rpm. The degree of polymerization of polyvinyl alcohol was 1700, and the degree of alcoholysis was 88%.

[0051] Example 4

[0052] The lignin sulfonate was treated at 120°C for 3h, and then 10 parts by mass of the treated lignin sulfonate, 80 parts by mass of polyvinyl alcohol, 5 parts by mass of glycerol, and 5 parts by mass of lithium chloride were fully mixed to obtain a premix. The premix was then melt-extruded and granulated by a twin-screw extruder to obtain a masterbatch. The extrusion temperatures from the feed section to the die were 175°C, 185°C, 190°C, 190°C, 200°C, and 200°C, respectively, and the screw speed was 50rpm. Then, a single screw was used to extrude the wire. The extrusion temperatures from the feed section to the die were 205°C and 200°C, respectively, and the extrusion rate was 20rpm. The degree of polymerization of polyvinyl alcohol was 1700, and the degree of alcoholysis was 88%.

[0053] Example 5

[0054] The lignin sulfonate was treated at 120°C for 3h, and then 10 parts by mass of the treated lignin sulfonate, 75 parts by mass of polyvinyl alcohol, 10 parts by mass of glycerol, and 5 parts by mass of lithium chloride were fully mixed to obtain a premix. The premix was then melt-extruded and granulated by a twin-screw extruder to obtain a masterbatch. The extrusion temperatures from the feed section to the die were 175°C, 185°C, 190°C, 190°C, 200°C, and 200°C, respectively, and the screw speed was 50rpm. Then, a single screw was used to extrude the wire. The extrusion temperatures from the feed section to the die were 205°C and 200°C, respectively, and the extrusion rate was 20rpm. The degree of polymerization of polyvinyl alcohol was 1700, and the degree of alcoholysis was 88%.

[0055] Example 6

[0056] The lignin sulfonate was treated at 120°C for 3h, and then 10 parts by mass of the treated lignin sulfonate, 80 parts by mass of polyvinyl alcohol, 5 parts by mass of zinc stearate, and 5 parts by mass of lithium chloride were fully mixed to obtain a premix. The premix was then melt-extruded and granulated by a twin-screw extruder to obtain a masterbatch. The extrusion temperatures from the feed section to the die were 175°C, 185°C, 190°C, 190°C, 200°C, and 200°C, respectively, and the screw speed was 50rpm. Then, a single screw was used to extrude the wire. The extrusion temperatures from the feed section to the die were 205°C and 200°C, respectively, and the extrusion rate was 20rpm. The degree of polymerization of polyvinyl alcohol was 1700, and the degree of alcoholysis was 88%.

[0057] Comparative Example 1

[0058] 100 parts by mass of polyvinyl alcohol (pure polyvinyl alcohol) was melt-extruded and granulated through a twin-screw extruder to obtain a masterbatch, and the extrusion temperatures from the feed section to the die were 175°C, 185°C, 190°C, 190°C, 200°C and 200°C, respectively, and the screw speed was 50rpm. Then, a single screw was used to extrude the wire, and the extrusion temperatures from the feed section to the die were 205°C and 200°C, respectively, and the extrusion rate was 20rpm. The degree of polymerization of the polyvinyl alcohol was 1700, and the degree of alcoholysis 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 the same.

[0060] Experimental Example 1

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

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

[0063] Depend on Figure 2 It can be seen that compared with Comparative Example 1, after adding lignin in Examples 1-3, the elongation at break is significantly improved. This is because lignin sulfonate and polyvinyl alcohol are cross-linked to form a network structure, which increases the toughness of the composite material.

[0064] Depend on Figure 3 , Figure 4 It can be seen that the digital photos of the water-soluble 3D printing support wires prepared in Examples 1-3 after being immersed in water at room temperature for 30 minutes show that the composite material is almost completely dissolved in the aqueous solution without obvious boundaries. However, the digital photos of Comparative Example 1 after being immersed in water at room temperature for 30 minutes show that the sample only absorbs water and swells but does not dissolve in the aqueous solution, with obvious boundaries.

[0065] Depend on Figure 5 It can be observed that compared with Comparative Example 1, the surface of the wire becomes smooth after adding lignin in Example 1, and the processing performance is improved under the same processing conditions.

[0066] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. An environmentally friendly, degradable, fast water-soluble 3D printing support material, characterized in that: The invention is composed of the following raw materials in parts by weight: 10-60 parts of lignin sulfonate, 40-90 parts of polyvinyl alcohol, 0-10 parts of lubricant, 0-10 parts of heat stabilizer and 1-10 parts of lithium chloride.

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

3. The environmentally friendly, degradable, fast water-soluble 3D printing support material according to claim 1, characterized in that: The lubricant is selected from at least one of glycerin, 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, characterized in that: The heat stabilizer is selected from at least one of dibutyltin dilaurate, dioctyltin dilaurate, dialkyltin maleate, dioctyltin maleate and dioctyltin bis(isooctyl mercaptoacetate).

5. A method for preparing an environmentally friendly, degradable, fast-dissolving water-soluble 3D printing support material, characterized in that: include: The lignin sulfonate is subjected to heat treatment to remove small molecule volatile and degradable substances in the lignin sulfonate; The heat-treated lignin sulfonate, polyvinyl alcohol, lubricant, heat stabilizer and lithium chloride are uniformly mixed to obtain a mixture; The mixture is extruded and granulated by a twin-screw extruder to obtain a blended material; The blended material is added into a single screw extruder for extrusion and drawing to obtain a fast water-soluble 3D printing support wire.

6. The method for preparing the environmentally friendly, degradable, fast water-soluble 3D printing support material according to claim 5, characterized in that: The heat treatment conditions are: treatment at 100-200° C. for 0.5-48 hours.

7. The method for preparing the environmentally friendly, degradable, fast water-soluble 3D printing support material according to claim 5, characterized in that: The extrusion temperature of the twin-screw extrusion granulation is 170-240° C., and the screw speed is 30-200 rpm.

8. The method for preparing the environmentally friendly, degradable, fast water-soluble 3D printing support material according to claim 5, characterized in that: The extrusion temperature of the extrusion wire drawing is 170-240° C., and the screw speed is 20-150 rpm.

9. An environmentally friendly, degradable, fast water-soluble 3D printing support material prepared by the method according to any one of claims 5 to 8.

10. Use of the environmentally friendly, degradable, fast-water-soluble 3D printing support material according to any one of claims 1 to 4 and 9 in 3D printing.

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