A 3D printed foamed part and its preparation method and its application in the field of foamed shoe materials

Abstract

The present invention discloses a 3D printed foamed part, its preparation method and application in the field of foamed shoe materials, relating to the technical field of processing of thermoplastic elastomer foaming materials. The preparation method of the 3D printed foamed part provided by the present invention first obtains a foamed filament melt through a specific extrusion process, controls the diameter of the filament melt during the extrusion process, and then makes it controllably stacked under the drive of a 3D printing device, and adjusts the parameters during the stacking process. By using the method provided by the present invention to prepare the 3D printed foamed part, a grid structure can be formed through controllable stacking, a part with a planar shape can be prepared, the obtained part has moderate cell size, the tensile fracture strength is as high as more than 35 N, the true density is as low as below 0.7 g / cm<supgt;3< / supgt;, it is applicable to the field of shoe materials, and the extrusion process of the obtained part is stable, the dimensional error is below 35 μm, and it has higher dimensional accuracy.

Description

Technical Field

[0001] The present invention relates to the technical field of thermoplastic elastomer foam material processing, and in particular to a 3D printed foamed part and a preparation method thereof and application in the field of foamed shoe materials. Background Art

[0002] Elastomer foam material is currently an important raw material for preparing foamed shoe materials such as insoles and uppers. When preparing foamed shoe materials, the molding methods include PU infusion, molded foaming, steam molding, etc. The above molding processes all require the use of molds to construct the curved surface structure of the shoe material and the pattern structure on the curved surface. Using mold processing and molding not only prolongs the preparation process, but also costs a lot of processing costs.

[0003] 3D printing technology can achieve mold-free molding and free structural design, and has become an important processing method for polymer materials. At present, reports have shown that 3D printing technology has been applied to the manufacture of shoe materials and has received widespread attention. However, the current 3D printed shoe parts are all solid structures. Although the structure is rich in shape, the true density is too high and the texture is too heavy, which limits its wide application.

[0004] In order to reduce the density and weight of 3D printed shoe parts, foaming the parts after 3D printing to obtain shoe materials is a feasible way. However, if foaming is performed after the 3D printed parts are formed, the thickness and defects of the parts will seriously affect the surface quality and expansion uniformity of the final shoe materials, resulting in a decrease in their tensile strength. In addition, foaming after 3D printing will change the size, shape and other parameters of the obtained parts, resulting in a decrease in the dimensional accuracy of the printed parts. For this reason, it is urgent to find a new process for preparing 3D printed foamed parts so that they can be applied to the requirements of the shoe material field, with a lighter density and higher dimensional accuracy and tensile strength. Summary of the invention

[0005] In order to solve the shortcomings of the prior art, the present invention provides a method for preparing a 3D printed foamed part. First, polymer particles containing a foaming agent are prepared, and then the polymer particles are injected into a 3D printing device for extrusion foaming and foaming melt stacking molding. By controlling parameters such as the diameter and stacking speed of the foaming wire melt during the 3D printing process, a 3D printed foamed part with high tensile strength, high dimensional accuracy and low density is obtained, which is suitable for use in the field of shoe materials.

[0006] Another object of the present invention is to provide a 3D printed foamed part prepared by the above preparation method.

[0007] Another object of the present invention is to provide an application of a 3D printed foamed product in the field of foamed shoe materials.

[0008] The above-mentioned purpose of the present invention is achieved through the following technical solutions:

[0009] A method for preparing a 3D printed foamed part comprises the following steps:

[0010] S1. Melt-extrude thermoplastic elastomer particles containing a foaming agent to obtain a foamed filament melt; the diameter of the foamed filament melt is 0.2-1.0 mm; the melt extrusion is performed by a single-screw extruder, and the single-screw extruder sequentially includes a first heating section, a second heating section, and a third heating section, the temperature of the first heating section is 0-30°C, the temperature of the second heating section is 150-300°C, and the temperature of the third heating section is 200-320°C;

[0011] S2. The foamed filament melt obtained in step S1 is 3D printed according to the planned path to obtain a 3D printed foamed part; wherein the stacking speed of the 3D printing is 80-120 mm / s and the printing temperature is 200-320°C.

[0012] In a specific embodiment of the present invention, the above-mentioned preparation method is carried out in a 3D printing device in which the wire extrusion unit is an extruder, so that the foamed wire melt obtained in step S1 is stacked according to the planned path to realize 3D printing.

[0013] The preparation method of the 3D printed foamed product provided by the present invention first extrude and foam a thermoplastic elastomer containing a foaming agent to obtain a foamed filament melt, and the obtained foamed filament melt is stacked and formed according to a planned path to obtain a 3D printed foamed product; by controlling the temperature during the extrusion process and the diameter, stacking speed and printing temperature of the foamed filament melt during the stacking process, a 3D printed foamed product with high tensile strength, high dimensional accuracy and low density is obtained, and the 3D printed foamed product has broad application prospects in the field of foamed shoe materials.

[0014] Specifically, in the preparation method provided by the present invention, the reason why the above parameters need to be controlled is that the temperature of the extrusion process, the stacking speed, the diameter of the foamed filament melt and the printing temperature (i.e., the temperature of the foamed molten material when stacked) will affect the degree of forming of the product. In the present invention, the extrusion die head of the 3D printing equipment (i.e., the extrusion die head of the extruder) extrude the filament melt, which needs to be constructed into a designed plane shape by stacking. The wire melt will foam at the moment of extrusion, so the inventor of this application has made special adjustments to the temperature of the three sections (feeding section, compression section and metering section) of the extruder in step S1 after a large number of experimental verifications, to ensure that the thermoplastic elastomer particles containing the foaming agent do not foam and expand when passing through the feeding section, i.e., the first heating section, to achieve stable transportation, and then melt in the screw of the compression section (second heating section) and be compacted by the screw structure to achieve densification between the particle structures and prevent the escape of the foaming agent; continue to melt and foam in the screw of the metering section (third heating section), and the foaming melt is stably transported to the die of the extruder through the metering properties of the screw structure. Generally speaking, the temperature of the feeding section of the extruder is usually not less than 100°C, but in the present invention, the temperature of the feeding section is higher than 30°C, which will cause excessive loss of the foaming agent in the raw material particles of step S1, thereby causing a decrease in the degree of foaming. In order to ensure the foaming agent content in the raw material particles, the temperature of the feeding section is controlled to 0-30°C, but the rapid glass transition and smooth extrusion of the raw materials can also be achieved without affecting the compression and melt foaming of the latter two sections in the extruder.

[0015] The parameters of the 3D printing process in step S2 and the extrusion process in step S1 jointly affect the dimensional accuracy and other properties of the obtained product. If the stacking speed of the foamed filament melt extruded in step S2 is too fast and the diameter of the foamed filament melt is too high, it is easy to cause a decrease in dimensional accuracy; if the stacking speed is too slow, the temperature of the filament melt is insufficient when stacking, which may cause loose adhesion, a decrease in tensile fracture strength, or even material damage. If the diameter of the foamed filament melt extruded by the extrusion die is too low, the bubbles formed during the extrusion process will be damaged, and the obtained product will not only have a decrease in tensile fracture strength and a greatly increased density, but may even be unable to be formed.

[0016] In a specific embodiment of the present invention, the printing temperature in step S2 is the temperature of the extruder die, and the temperature of the extruder die is consistent with the chamber temperature of the 3D printing device. The printing temperature determines the morphology of the foamed filament melt during the 3D printing process. If the printing temperature is too high, the bubbles formed during the extrusion process will be severely broken, and no effective bubbles can be observed in the final product. At the same time, the filament melt will be severely adhered during the extrusion stacking process, the density will increase, and it will be difficult to form; if the printing temperature is too low, it will also make it difficult to form, and the tensile fracture strength will decrease, because the stratification between the filament melts is serious during the stacking process.

[0017] In a specific embodiment of the present invention, the diameter of the foaming filament melt is controlled to be 0.2-1.0 mm by controlling the die size of the extrusion unit in the 3D printing device. More specifically, the die size of the extrusion unit is 0.3-2.0 mm. In the present invention, the die size of the extrusion unit is ≥ the diameter of the foaming filament melt.

[0018] In a specific embodiment of the present invention, the temperature of the first heating section is controlled to be 0-30° C. by connecting the first heating section screw to a cold air system.

[0019] In a specific embodiment of the present invention, the loss rate of the blowing agent of the thermoplastic elastomer containing the blowing agent is less than 10%, preferably less than or equal to 5%, when passing through the feeding section.

[0020] In a specific embodiment of the present invention, the residence time of the thermoplastic elastomer containing the foaming agent passing through the second heating section and / or the third heating section is 0.1 to 1.5 s, preferably 0.2 to 1.0 s, and more preferably 0.3 to 0.8 s.

[0021] In a specific embodiment of the present invention, the screw speed of the single screw extruder in step S1 is 20-50 rpm.

[0022] Preferably, the diameter of the foamed wire melt in step S1 is 0.3-0.5 mm.

[0023] In a specific embodiment of the present invention, the diameter of the foamed filament melt is controlled to be 0.3-0.5 mm by controlling the die size of the extrusion unit in the 3D stacking device to be 0.5-1.2 mm.

[0024] In a specific embodiment of the present invention, the extrusion speed of the melt extrusion in step S1 is 0.5-5 kg / h.

[0025] In a specific embodiment of the present invention, the thermoplastic elastomer particles containing a foaming agent in step S1 have a flow point of 130-250°C.

[0026] Preferably, the stacking speed of the 3D printing in step S2 is 90-110 mm / s.

[0027] Preferably, the printing temperature of the 3D printing in step S2 is 90-120°C.

[0028] Within a certain range, the higher the stacking temperature of 3D printing, the better the performance of the 3D printed parts. However, too high a temperature will cause the bubbles formed by extrusion foaming to rupture, which will in turn lead to a decrease in the performance of the 3D printed parts.

[0029] More preferably, the temperature control accuracy of the printing temperature during the 3D printing in step S2 is 0.5~5°C, preferably 1~3°C.

[0030] In a specific embodiment of the present invention, the rotation angle of the 3D printing in step S2 is ≥10°.

[0031] In a specific embodiment of the present invention, the rotational angular velocity of the 3D printing in step S2 is 0-60 rad / s, preferably 0-30 rad / s.

[0032] Preferably, the 3D printed foamed part includes the following raw materials by weight: 80-100 parts of thermoplastic elastomer, 0.08-20 parts of foaming agent, 0-10 parts of nucleating agent, 0-1 part of chain extender, 0-0.5 parts of antioxidant, and 0-2 parts of antistatic agent.

[0033] More preferably, the mass fraction of the foaming agent is 0.08 to 8 parts.

[0034] More preferably, the mass fraction of the foaming agent is 0.4 to 6.4 parts.

[0035] More preferably, the thermoplastic elastomer includes at least one of thermoplastic polyurethane, polyester elastomer, nylon elastomer, ethylene / vinyl acetate copolymer blend system, polyolefin elastomer, styrene elastomer, natural rubber and synthetic rubber.

[0036] More preferably, the foaming agent includes at least one of CO2 fluid, N2 fluid, combustible alkane, azodicarbonamide (AC foaming agent), carbonate, and N,N-dinitrosopentamethylenetetramine (H foaming agent).

[0037] In a specific embodiment of the present invention, the combustible alkane includes at least one of n-pentane, isopentane, butane and freon.

[0038] In a specific embodiment of the present invention, the thermoplastic elastomer particles containing a foaming agent in step S1 are prepared by blending a thermoplastic elastomer with a foaming agent. When the foaming agent is a fluid (at least one of a CO2 fluid, a N2 fluid, and a combustible alkane), the thermoplastic elastomer and the foaming agent are blended by impregnation.

[0039] In a specific embodiment of the present invention, the thermoplastic elastomer particles containing a foaming agent in step S1 may be in at least one of a circular, elliptical, and wedge-shaped shape, the diameter of the particles is 0.5-5.0 mm, the fluctuation range of the average diameter is 0.5-1 mm, and the hardness range of the particles is Shore A10-Shore D85.

[0040] More preferably, the nucleating agent includes at least one of calcium carbonate, talc, mica, montmorillonite, nano-silica, carbon black, and carbon nanotubes.

[0041] More preferably, the chain extender comprises at least one of a difunctional acid derivative, an isocyanate, an anhydride, and an epoxide.

[0042] More preferably, the antioxidant includes at least one of an amine antioxidant and a phosphorus antioxidant.

[0043] More preferably, the particle size of the nucleating agent is 0.05-5 μm.

[0044] More preferably, the antistatic agent includes a hydrophobic antistatic auxiliary agent.

[0045] In a specific embodiment of the present invention, the thermoplastic elastomer particles containing a blowing agent are prepared by blending a blowing agent with thermoplastic elastomer particles.

[0046] Preferably, the planning path of the 3D printing in step S2 includes at least one of a grid structure, a tetrahedron structure, a straight line structure, a triangular structure, an inner hexagonal structure, a cube structure, a cube partition structure, an octagonal structure, a concentric circle structure, a zigzag structure, a cross structure, a cross 3D structure, a spiral icosahedron structure, a lightning-shaped structure, and a reinforced frame, and the grid structure includes at least one of an in-plane grid structure and an interlayer grid structure. In a specific embodiment of the present invention, the above structures are all structures that come with the 3D printing software.

[0047] The present invention is expected to prepare a planar three-dimensional product suitable for the field of shoe materials, but what is extruded is a wire melt, which requires stacking between the wire melts. When the wire melts are stacked to form a plane through an in-plane grid structure, it is more conducive to air permeability, and the connection points between the wire melts and the wire melts can also improve the tensile fracture strength of the entire product. At the same time, since the 3D printing process is actually a process of stacking layer by layer, it is set in the planned printing path so that the grid structure is also stacked between the layers, which is also more conducive to air permeability and the reduction of true density.

[0048] The principle of including a reinforced border in the 3D printing planning path is similar to that of "locking the edge" of clothes, and the purpose is also to improve the strength of the product.

[0049] More preferably, the number of lines of the reinforced border is 1-10, preferably 2-8, and more preferably 3-6.

[0050] More preferably, the distance between two adjacent parallel wire melts in the in-plane grid structure is 0.5-3.0 mm, more preferably 0.8-2.0 mm.

[0051] More preferably, the spacing between two adjacent layers in the interlayer grid structure is 0.5-2.0 mm.

[0052] The present invention also protects a 3D printed foamed part prepared by the above preparation method.

[0053] In a specific embodiment of the present invention, the above-mentioned 3D printed foamed product can be at least one of a foamed upper product, a foamed insole product, a foamed midsole product, and a foamed midsole product.

[0054] In a specific embodiment of the present invention, the actual density of the 3D printed foamed product is 0.1-0.9 g / cm 3 , preferably 0.2~0.7g / cm 3 , more preferably 0.3 to 0.6 g / cm 3 .

[0055] In a specific embodiment of the present invention, the cell size distribution range inside the above-mentioned 3D printed foamed part is 8-35 μm.

[0056] The present invention also protects an application of the above-mentioned 3D printed foamed product in the field of foamed shoe materials.

[0057] Foamed shoe materials are subjected to repeated stretching, bending, and compression in a long-term service environment. At the same time, the structural stability, comfort, and elasticity of the foamed shoe materials significantly affect the wearer's athletic performance. Therefore, the application field of shoe materials has very high requirements for the tensile strength, ball rebound, compression permanent deformation, and cyclic compression fatigue of the foamed materials. The foamed material provided by the present invention has high tensile strength, high dimensional accuracy, and low density. The low density means high foaming rate, high elasticity, and high comfort. The high tensile strength means that the shoe material has strong durability. Therefore, the foamed material provided by the present invention has broad application prospects in the field of foamed shoe materials.

[0058] Compared with the prior art, the present invention has the following beneficial effects:

[0059] The method provided by the present invention is used to prepare 3D printed foam products, which can produce three-dimensional products with a planar shape, a reinforced frame structure and a grid structure. The tensile strength of the obtained products is as high as 35N or more, and the true density is as low as 0.7g / cm 3 The following is applicable to the field of shoe materials, and the obtained parts have a smooth extrusion process, moderate pore size, a dimensional error of less than 35 μm, and higher dimensional accuracy. BRIEF DESCRIPTION OF THE DRAWINGS

[0060] Figure 1~Figure 2 This is a schematic diagram of a 3D printed foamed part obtained in Example 1 of the present invention.

[0061] Figure 3 This is a schematic diagram of part of the 3D printing planning path in the 3D printing software used in the present invention. DETAILED DESCRIPTION

[0062] The present invention is further described below in conjunction with specific embodiments, but the embodiments do not limit the present invention in any form. Unless otherwise specified, the raw materials and reagents used in the embodiments of the present invention are conventionally purchased raw materials and reagents. The raw material information used in each embodiment and comparative example is as follows (the part involving hardness refers to Shore hardness):

[0063] Thermoplastic elastomer A: polyurethane TPU, hardness 60A, BASF, Germany.

[0064] Thermoplastic elastomer B: TPEE, hardness 80A, DuPont, USA.

[0065] Thermoplastic elastomer C: EVA, hardness 40A, Tosoh, Japan.

[0066] Nucleating agent: calcium carbonate, average particle size 1 μm, commercially available.

[0067] Chain extender: Epoxy chain extender, commercially available.

[0068] Antioxidant: Hindered phenol antioxidant, commercially available.

[0069] Antistatic agent: hydrophobic antistatic agent, commercially available.

[0070] Embodiments 1 to 9

[0071] This embodiment provides a series of methods for preparing 3D printed foamed parts with different processing parameters, including the following steps:

[0072] S1. A blowing agent and thermoplastic elastomer particles are blended at room temperature to prepare thermoplastic elastomer particles containing a blowing agent, and the thermoplastic elastomer particles containing a blowing agent are put into a single-screw extruder for melt extrusion to obtain a foamed filament melt, wherein the extrusion rate of the foamed filament melt is 3.2 kg / h; the blowing agent loss rate of the thermoplastic elastomer containing a blowing agent is less than 5% when passing through the feeding section, and the residence time after passing through the second heating section and the third heating section is 0.5 s; the screw speed is 30 rpm;

[0073] S2. The foamed filament melt obtained in step S1 is 3D printed according to the planned path to obtain a 3D printed foamed part; wherein the rotation angle of 3D printing is ≥10°, the rotation angular velocity is 15 rad / s, and the temperature control accuracy of the printing temperature is 2°C; the planned path of 3D printing includes a grid structure and a reinforced frame, such as Figure 1~Figure 2As shown; in this embodiment, the number of lines of the reinforced frame is 3, and the grid structure is an in-plane grid structure, in which the distance between two adjacent parallel wire melts is 1.5 mm.

[0074] In this embodiment, the following components are included by weight: 85 parts of thermoplastic elastomer, 10 parts of foaming agent, 5 parts of nucleating agent, 0.3 parts of chain extender, 0.2 parts of antioxidant, and 1 part of antistatic agent.

[0075] The specific processing parameters in this embodiment are shown in Table 1 below:

[0076] Table 1. Specific processing parameters in Examples 1 to 9

[0077]

[0078] Comparative Example 1

[0079] A method for preparing a 3D printed foamed part, which differs from Example 1 only in that:

[0080] The stacking speed of the 3D printing in step S2 is 150 mm / s.

[0081] Comparative Example 2

[0082] A method for preparing a 3D printed foamed part, which differs from Example 1 only in that:

[0083] The stacking speed of the 3D printing in step S2 is 50 mm / s.

[0084] Comparative Example 3

[0085] A method for preparing a 3D printed foamed part, which differs from Example 1 only in that:

[0086] The diameter of the foamed wire melt in step S1 is 1.5 mm.

[0087] Comparative Example 4

[0088] A method for preparing a 3D printed foamed part, which differs from Example 1 only in that:

[0089] The diameter of the foamed wire melt in step S1 is 0.1 mm.

[0090] Comparative Example 5

[0091] A method for preparing a 3D printed foamed part, which differs from Example 1 only in that:

[0092] The printing temperature of the 3D printing in step S2 is 350°C.

[0093] Comparative Example 6

[0094] A method for preparing a 3D printed foamed part, which differs from Example 1 only in that:

[0095] The printing temperature of the 3D printing in step S2 is 60°C.

[0096] Comparative Example 7

[0097] A method for preparing a 3D stacked foamed product, which differs from Example 1 only in that:

[0098] The temperature of the feeding section in step S1 is 100°C.

[0099] Performance Testing

[0100] Tensile breaking strength test: measured by a tensile testing machine.

[0101] Foaming behavior, stacking condition: measured by visual observation.

[0102] Dimension error measurement: measured by caliper.

[0103] Measurement of pore size and distribution: Observe the pore distribution and pore size under a microscope.

[0104] True density test: tested by density meter.

[0105] The specific test data are shown in Table 2 below:

[0106] Table 2. Performance test data of 3D printed foamed parts obtained in Examples and Comparative Examples

[0107]

[0108]

[0109]

[0110]

[0111] From the above table 2 and Figure 1~Figure 2 It can be seen that the method provided by the present invention can be used to prepare 3D printed foam parts, and a planar material containing a reinforced frame structure and a grid structure can be obtained. The tensile fracture strength of the obtained parts is as high as 35N and the true density is as low as 0.7g / cm 3The following is applicable to the field of shoe materials, and the extrusion process of the obtained product is stable, the bubble size is moderate, the dimensional error is below 35μm, and it has higher dimensional accuracy. Among them, according to the data of Examples 5 to 7 in Table 2, when the stacking speed in the 3D printing process is within the preferred range of 90 to 110 mm / s of the present invention (Example 5), the error range of the obtained product is smaller (the maximum error does not exceed 35μm), the tensile breaking strength is higher, and the true density is also lower. According to the data of Examples 5, 9 and Comparative Example 5, it can be seen that within the temperature range of 90 to 150°C, the performance of the product will actually be improved to a certain extent as the temperature rises, but when the temperature is too high (Comparative Example 5), the bubbles formed by extrusion foaming will rupture during the printing process, which will lead to a decrease in the performance of the product.

[0112] According to the data of Comparative Examples 1 and 2 in Table 2 above, it can be seen that if the stacking speed of 3D printing in step S2 is too high or too low, the performance of the obtained product will be reduced. When the stacking speed is too high (Comparative Example 1), the actual density of the obtained 3D printed foamed product is 0.7 g / cm 3 , there is no obvious problem with the internal pore distribution, but the stacking accuracy is poor due to the excessively fast stacking speed, the shape of the obtained thermoplastic elastomer 3D printed foamed part is not accurate enough, and the poor stacking accuracy leads to stacking deviation, which in turn causes the part to break easily during the stretching process, and the part has a low tensile strength at break of 20N; when the stacking speed is too slow (Comparative Example 2), there are also no obvious problems with the true density and pore distribution of the obtained part, but the stacking speed is too slow, resulting in insufficient temperature of the wire melt during stacking, loose adhesion, poor stacking strength, and inability to effectively form an integral part, resulting in a low tensile strength at break of 22N.

[0113] According to the data of Comparative Examples 3 to 4 in Table 2 above, it can be seen that the diameter of the foamed wire melt in step S1 is too high or too low, which will also lead to the performance degradation of the obtained product. When the diameter of the wire melt is too low (Comparative Example 4), the product cannot even be formed. This is because the diameter of the wire melt is too high (Comparative Example 3), the internal heating is insufficient, and it is difficult to effectively form bubbles. At the same time, the diameter of the wire melt is too thick to achieve accurate stacking during the stacking process, and the error is large. Although the product in Comparative Example 3 has excellent tensile properties due to its dense structure, its dimensional error range is as high as 200μm or more, and the material with dense structure is heavy and not suitable for use as a shoe material; the diameter of the wire melt is too low (Comparative Example 4), the wire melt has bubble damage during the extrusion process, so effective bubbles cannot be observed in the finished product, and to reduce the diameter of the wire melt means that the diameter of the extrusion die must also be reduced. The size of the extrusion die is too low to make it impossible to extrude continuously, but the stacking progress continues to progress, so Comparative Example 4 cannot form a complete product, and ultimately the breaking tensile strength of the product is only 18N.

[0114] According to the data of Comparative Examples 5-6 in Table 2 above, it can be seen that the temperature of the printing process in step S2 also has a key influence on the performance of the obtained product. If the printing temperature is too high (Comparative Example 5), the cells will be severely broken during the foaming process and effective cells cannot be formed. In addition, if the temperature of the extruded filament melt is too high, it is easy to stick together, and the product precision is poor, which ultimately leads to a tensile strength of 20N at break of the product. If the printing temperature is too low (Comparative Example 6), the stacking process cannot be adhered and stacked, and it is easy to delaminate, resulting in a significant decrease in strength. The tensile strength of the product at break is 17N.

[0115] According to the data of Comparative Example 7 in Table 2 above, it can be seen that the conventional extrusion process for the melt extrusion foaming in the present invention can easily lead to uneven mixing of raw materials and loss of foaming agent due to the excessively high temperature in the feeding section, resulting in the inability to form a product.

[0116] Finally, it should be noted that the above embodiments are only used to illustrate the technical solution of the present invention rather than to limit the scope of protection of the present invention. Although the present invention has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that the technical solution of the present invention can be modified or replaced by equivalents without departing from the essence and scope of the technical solution of the present invention.

Claims

1. A method for preparing a 3D printed foamed part, characterized in that: The steps include: S1. Melt-extrude thermoplastic elastomer particles containing a foaming agent to obtain a foamed filament melt; the diameter of the foamed filament melt is 0.2-1.0 mm; the melt extrusion is performed by a single-screw extruder, and the single-screw extruder sequentially includes a first heating section, a second heating section, and a third heating section, the temperature of the first heating section is 0-30°C, the temperature of the second heating section is 150-300°C, and the temperature of the third heating section is 200-320°C; S2. The foamed filament melt obtained in step S1 is 3D printed according to the planned path to obtain a 3D printed foamed part; wherein the stacking speed of the 3D printing is 80-120 mm / s and the printing temperature is 200-320°C.

2. The method for preparing a 3D printed foamed part according to claim 1, characterized in that: The diameter of the foamed wire melt in step S1 is 0.3-0.5 mm.

3. The method for preparing a 3D printed foamed part according to claim 1, characterized in that: The flow point of the thermoplastic elastomer particles containing a foaming agent in step S1 is 130-250°C.

4. The method for preparing a 3D printed foamed part according to claim 1, characterized in that: The stacking speed of the 3D printing in step S2 is 90-110 mm / s.

5. The method for preparing a 3D printed foamed part according to claim 1, characterized in that: The 3D printed foamed component includes the following preparation raw materials by weight: 80-100 parts of thermoplastic elastomer, 0.08-20 parts of foaming agent, 0-10 parts of nucleating agent, 0-1 part of chain extender, 0-0.5 parts of antioxidant, and 0-2 parts of antistatic agent.

6. The method for preparing a 3D printed foamed part according to claim 5, characterized in that: Include at least one of the following (a) to (g): (a) the thermoplastic elastomer comprises at least one of thermoplastic polyurethane, polyester elastomer, nylon elastomer, ethylene / vinyl acetate copolymer, polyolefin elastomer, styrene elastomer, natural rubber and synthetic rubber; (b) the foaming agent comprises at least one of CO2 fluid, N2 fluid, combustible alkane, azodicarbonamide, carbonate, and N,N-dinitrosopentamethylenetetramine; (c) the nucleating agent comprises at least one of calcium carbonate, talc, mica, montmorillonite, nano-silica, carbon black and carbon nanotubes; (d) the chain extender comprises at least one of a difunctional acid derivative, an isocyanate, an anhydride, and an epoxide; (e) the antioxidant comprises at least one of an amine antioxidant and a phosphorus antioxidant; (f) the particle size of the nucleating agent is 0.05-5 μm; (g) The antistatic agent includes a hydrophobic antistatic auxiliary agent.

7. The method for preparing a 3D printed foamed part according to claim 1, characterized in that: In step S2, the planned path of 3D printing includes at least one of a grid structure and a reinforced frame, and the grid structure includes at least one of an in-plane grid structure and an inter-layer grid structure.

8. The method for preparing a 3D printed foamed part according to claim 7, characterized in that: Include at least one of the following (a) to (c): (a) The number of lines of the reinforced border is 1 to 10; (b) The spacing between two adjacent parallel wire melts in the in-plane grid structure is 0.5-3.0 mm; (c) The spacing between two adjacent layers in the interlayer grid structure is 0.5~2.0 mm.

9. A 3D printed foamed part prepared by the preparation method according to any one of claims 1 to 8.

10. Application of the 3D printed foamed product according to claim 9 in the field of foamed shoe materials.

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