3D printing foamed mesh and its preparation method and shoe upper

Abstract

The application provides a 3D printing foamed mesh and a preparation method and a vamp thereof, and belongs to the technical field of 3D printing. Firstly, a thermoplastic resin mixture containing a foaming agent is melt-extruded, and the obtained thermoplastic resin composite material is 3D printed according to a planned path to obtain a 3D printing mesh. Secondly, the 3D printing mesh is soaked in a solvent. Finally, the soaked 3D printing mesh is impregnated with a supercritical fluid and then foamed to obtain a 3D printing foamed mesh. The method provided by the application is used to prepare the 3D printing foamed mesh, so that a structure of double-diameter pores is formed in the lines of the 3D printing foamed mesh, and the tensile strength and tear strength of the 3D printing foamed mesh are improved.

Description

Technical Field

[0001] This application relates to the field of 3D printing technology, specifically to a 3D printed foamed mesh fabric, its preparation method, and a shoe upper. Background Technology

[0002] Mesh fabric, with its advantages of high strength, good breathability, and wovenability, has been widely used in many fields such as footwear, apparel, and sports protection. Atmospheric pressure mesh materials are made from fibers such as polyester, and weaving methods include knitting and weaving. Thermoplastic elastomer yarns, with their high abrasion resistance and transparency, are also used in mesh weaving. The process of making shoe upper mesh involves dozens of steps, including fiber spinning, dyeing, weaving structure design, weaving, and die-cutting. From submitting a request to receiving a sample, it takes more than a month, which limits the development of rapid prototyping for shoe upper mesh fabrics.

[0003] 3D printing is an additive manufacturing technology that creates solid objects by adding materials layer by layer based on 3D CAD data. Through 3D structural design, it allows for greater design freedom and larger internal voids. FDM-3D printing, characterized by extruding polymer melts, can print linear structures and simultaneously achieve online welding and weaving of these lines. FDM printing of thermoplastic elastomers has already been used in the rapid manufacturing of shoe uppers. However, existing FDM printing technology is not suitable for manufacturing low-hardness thermoplastic elastomer materials. The resulting 3D-printed shoe uppers suffer from high hardness, large weight, and lack of flexibility, limiting the application of 3D printing technology in the shoe upper field.

[0004] Patent CN119408151A discloses the use of thermoplastic elastomer particles containing foaming agents as materials for 3D printing to prepare 3D printed foamed shoe uppers with foamed structures and low hardness. However, the foaming stage of patent CN119408151A occurs above the viscosity flow temperature of the polymer. The foaming agent will diffuse rapidly at high temperatures, and the residual heat in the stacked parts will promote the rapid growth of nucleated cells, resulting in a large diameter of the cell structure in the 3D printed foamed parts. This makes it difficult to achieve both low density and high mechanical properties in the printed foamed parts. Summary of the Invention

[0005] The purpose of this disclosure is to overcome the shortcomings of the prior art and to provide a 3D printed foamed mesh fabric, its preparation method, and a shoe upper.

[0006] To achieve the above objectives, the technical solution adopted in this disclosure is as follows: Firstly, a method for preparing 3D printed foamed mesh fabric is provided, comprising the following steps:

[0007] S1: Add the thermoplastic resin mixture to a single-screw extruder for melt extrusion to obtain a thermoplastic resin composite material; 3D print the thermoplastic resin composite material to obtain a 3D printed mesh; wherein the number of stacked layers in the 3D printing is 1-4 layers;

[0008] S2: Immerse the 3D printed mesh in a solvent, then wash and dry it to obtain a pretreated 3D printed mesh; wherein the solvent is a mixture of alcohol and acetone, and the immersion temperature is 10-50℃; the volume ratio of the alcohol and acetone is (70:30)-(50:50).

[0009] S3: After impregnating the pretreated 3D printed mesh with supercritical fluid, it is foamed to obtain 3D printed foamed mesh.

[0010] The thermoplastic resin mixture comprises the following raw materials in parts by weight: 75-90 parts thermoplastic elastomer, 0.1-10 parts foaming agent, 1-10 parts color masterbatch, 0.1-10 parts matting agent, 0.1-5 parts lubricant, 0.1-1 part nucleating agent, and 0.1-0.5 parts antioxidant;

[0011] The Shore hardness of the thermoplastic elastomer is 50A-80A.

[0012] In some implementations, the number of stacked layers in the 3D printing is 2-3.

[0013] In some embodiments, the volume ratio of the alcohol to acetone is (65:35) to (55:45).

[0014] In some embodiments, the antioxidant is a phosphite antioxidant.

[0015] In some embodiments, in step S2, the soaking temperature is 20-40°C and the soaking time is 1-30 minutes.

[0016] In some embodiments, the alcohol includes at least one of monohydric alcohols and polyhydric alcohols.

[0017] In some embodiments, the actual density of the 3D printed mesh is 0.7-1.1 g / cm³. 3 .

[0018] In some embodiments, the supercritical fluid impregnation temperature is 80-180°C, the pressure is 10-30 MPa, and the time is 0.1-1.0 h.

[0019] In some embodiments, the supercritical fluid includes at least one of CO2 fluid and N2 fluid.

[0020] In some embodiments, the solubility of the supercritical fluid in the 3D printed foamed mesh is 0.5-8%.

[0021] In some implementations, at least one of the following conditions is met:

[0022] (a) The thermoplastic elastomer includes at least one of thermoplastic polyurethane, thermoplastic polyester elastomer, polyamide, hydrogenated styrene-butadiene block copolymer, ethylene-vinyl acetate copolymer, polyolefin elastomer, and olefin block copolymer;

[0023] (b) The foaming agent comprises at least one of CO2 fluid, N2 fluid, flammable alkane, azodicarbonamide, carbonate, and N,N-dinitrospentamethylenetetramine;

[0024] (c) The nucleating agent includes at least one of calcium carbonate, talc, mica, montmorillonite, nano silica, carbon black, and carbon nanotubes;

[0025] (d) The color masterbatch includes organic dyes;

[0026] (e) The matte agent comprises at least one of sorbitol monopalmitate and xylitol ester;

[0027] (f) The lubricant includes at least one of polyethylene wax, stearic acid, lead stearate, zinc stearate, and paraffin wax;

[0028] (g) The melt mass flow rate of the thermoplastic elastomer at 210°C and 2.16 kg is 0.2-12 g / 10 min.

[0029] Secondly, a 3D printed foamed mesh fabric is provided, which is prepared by the method for preparing the 3D printed foamed mesh fabric.

[0030] In some embodiments, the areal density of the 3D printed foamed mesh is 100-800 g / m². 2 The tensile strength is ≥10kgf and the tear strength is ≥5kgf. The lines of the 3D printed foamed mesh have large-diameter cells and small-diameter cells. The average diameter of the large-diameter cells is 50-100μm and the average diameter of the small-diameter cells is 1-30μm.

[0031] Thirdly, a shoe upper is provided, comprising the aforementioned 3D-printed foamed mesh.

[0032] Compared with the prior art, the beneficial effects of this disclosure are as follows: In the 3D printing process of this application, a thermoplastic resin composite material containing a foaming agent is melt-extruded. During the melt extrusion process, the filament melt is pre-foamed. The filament melt is stacked to build the designed planar shape to obtain a pre-foamed 3D printed mesh. By immersing the 3D printed mesh in a solvent, defects in the lattice structure of the 3D printed mesh are eliminated while maintaining structural and diameter stability. This reduces the probability of surface bubbles forming during the foaming process after supercritical fluid impregnation, and forms a double-diameter cell structure in the lines of the 3D printed foamed mesh, thereby improving the tensile strength and tear strength of the 3D printed foamed mesh. Attached Figure Description

[0033] Figure 1 This is a schematic diagram of a 3D printed mesh fabric according to this application;

[0034] Figure 2 This is an appearance diagram of the 3D printed foamed mesh fabric of Example 1;

[0035] Figure 3 This is a diagram showing the appearance of the 3D printed foam mesh fabric in Comparative Example 1. Detailed Implementation

[0036] To facilitate understanding of this disclosure, a more complete description will be provided below. However, this disclosure may be implemented in many different forms and is not limited to the embodiments described herein. Rather, these embodiments are provided to provide a more thorough and complete understanding of the disclosure.

[0037] As used in this article:

[0038] "Prepared from" is synonymous with "comprising". The terms "comprising", "including", "having", "containing", or any other variations thereof as used herein are intended to cover non-exclusive inclusion. For example, a composition, step, method, article, or apparatus that includes the listed elements is not necessarily limited to those elements, but may include other elements not expressly listed or elements inherent to such composition, step, method, article, or apparatus.

[0039] The conjunction "composed of..." excludes any unspecified elements, steps, or components. If used in a claim, this phrase makes the claim closed, excluding materials other than those described, except for associated conventional impurities. When the phrase "composed of..." appears in a clause of the body of a claim rather than immediately following it, it limits only the elements described in that clause; other elements are not excluded from the claim as a whole.

[0040] When a quantity, concentration, or other value or parameter is expressed as a range, a preferred range, or a range defined by a series of upper and lower preferred values, this should be understood as specifically disclosing all ranges formed by any pair of any upper or preferred value with any lower or preferred value, regardless of whether the range is disclosed individually. For example, when the range “1-5” is disclosed, the described range should be interpreted as including ranges “1-4”, “1-3”, “1-2”, “1-2 and 4-5”, “1-3 and 5”, etc. When numerical ranges are described herein, unless otherwise stated, the range is intended to include its endpoints and all integers and fractions within that range.

[0041] In these embodiments, unless otherwise specified, the portions and percentages are all by weight.

[0042] "Parts by mass" refers to the basic unit of measurement that expresses the mass ratio of multiple components. One part can represent any unit mass, such as 1g or 2.689g. If we say that component A has 'a' parts by mass and component B has 'b' parts by mass, it means that the mass ratio of component A to component B is a:b. It is important to understand that, unlike mass percentage content, the sum of the mass parts of all components is not limited to 100 parts.

[0043] "And / or" is used to indicate that one or both of the described situations may occur, for example, A and / or B includes (A and B) and (A or B).

[0044] In a first aspect, this application provides a method for preparing 3D printed foamed mesh fabric, comprising the following steps:

[0045] S1: As Figure 1 As shown, a thermoplastic resin mixture is added to a single-screw extruder for melt extrusion to obtain a thermoplastic resin composite material; the thermoplastic resin composite material is then 3D printed to obtain a 3D printed mesh; wherein the number of stacked layers in the 3D printing is 1-4 layers;

[0046] S2: Immerse the 3D printed mesh in a solvent, then wash and dry it to obtain a pretreated 3D printed mesh; wherein the solvent is a mixture of alcohol and acetone, and the immersion temperature is 10-50℃; the volume ratio of the alcohol and acetone is (70:30)-(50:50).

[0047] S3: After impregnating the pretreated 3D printed mesh with supercritical fluid, it is foamed to obtain 3D printed foamed mesh.

[0048] The thermoplastic resin mixture comprises the following raw materials in parts by weight: 75-90 parts thermoplastic elastomer, 0.1-10 parts foaming agent, 1-10 parts color masterbatch, 0.1-10 parts matting agent, 0.1-5 parts lubricant, 0.1-1 part nucleating agent, and 0.1-0.5 parts antioxidant;

[0049] The Shore hardness of the thermoplastic elastomer is 50A-80A.

[0050] In this application, a thermoplastic resin mixture containing a foaming agent is melt-extruded. During the melt extrusion process, the melt undergoes pre-foaming. The melt is stacked to build a designed planar shape, resulting in a pre-foamed 3D printed mesh. By immersing the 3D printed mesh in a solvent, defects in the lattice structure of the 3D printed mesh are eliminated while maintaining structural and pore diameter stability. This reduces the probability of surface bubbles forming during the foaming process after supercritical fluid impregnation, resulting in a double-diameter pore structure within the lines of the 3D printed foamed mesh, thereby improving its tensile and tear strength. The pre-foaming degree of the 3D printed mesh is higher than 1.1 g / cm³. 3 At this time, the 3D printed mesh will have an open structure inside, which will cause the 3D printed mesh to no longer expand during the supercritical fluid autoclave foaming process.

[0051] Specifically, the pre-foaming degree of the 3D printed mesh is characterized by its actual density, which is 0.7-1.1 g / cm³. 3 For example, it can be 0.7 g / cm³. 3 0.75 g / cm 3 0.8 g / cm 3 0.85 g / cm 3 0.9 g / cm 3 0.95 g / cm 3 1.0 g / cm 3 1.5 g / cm 3 1.1 g / cm 3 The range of values ​​consisting of one or both of these. This application obtains 3D printed mesh fabrics of different true densities by adjusting the temperature of the melt extrusion.

[0052] Specifically, the weight parts of the thermoplastic elastomer can be one of 75 parts, 77 parts, 80 parts, 83 parts, 85 parts, 88 parts, or 90 parts, or any value between two of them.

[0053] Specifically, the weight parts of the foaming agent can be one or any two of the following: 0.1 parts, 0.5 parts, 1 part, 1.5 parts, 2 parts, 2.5 parts, 3 parts, 4 parts, 5 parts, 6 parts, 7 parts, 7.5 parts, 8 parts, 8.5 parts, 9 parts, 9.5 parts, and 10 parts.

[0054] Specifically, the weight of the color masterbatch can be one or any two of the following: 1, 2, 3, 4, 5, 6, 7, 8, 9, or 10 parts.

[0055] Specifically, the weight parts of the matte agent can be one or any two of the following: 0.1 parts, 0.5 parts, 1 part, 1.5 parts, 2 parts, 2.5 parts, 3 parts, 4 parts, 5 parts, 6 parts, 7 parts, 7.5 parts, 8 parts, 8.5 parts, 9 parts, 9.5 parts, and 10 parts.

[0056] Specifically, the weight parts of the lubricant can be one of, or any two of, 0.1 parts, 0.5 parts, 1 part, 1.5 parts, 2 parts, 2.5 parts, 3 parts, 3.5 parts, 4 parts, 4.5 parts, or 5 parts.

[0057] Specifically, the weight of the nucleating agent can be one or any two of the following: 0.1 parts, 0.2 parts, 0.3 parts, 0.4 parts, 0.5 parts, 0.6 parts, 0.7 parts, 0.8 parts, 0.9 parts, and 1 part.

[0058] Specifically, the antioxidant can be in the range of 0.1 parts, 0.2 parts, 0.3 parts, 0.4 parts, 0.5 parts by weight, or any combination thereof.

[0059] Specifically, the Shore hardness of the thermoplastic elastomer can be one of 50 A, 55 A, 60 A, 65 A, 70 A, 75 A, 80 A or any two of them; preferably 60-70 A.

[0060] In this application, the Shore hardness of thermoplastic elastomers affects the performance of 3D printed foamed mesh. Specifically, if the Shore hardness of the thermoplastic elastomer is too low, the sample surface will become sticky and the tensile and tear strength will decrease rapidly. If the Shore hardness of the thermoplastic elastomer is too high, the supercritical foaming temperature will be too high, the material will be prone to degradation and yellowing, and the tensile and tear strength will decrease rapidly.

[0061] Specifically, the number of stacked layers in the 3D printing is 1-4 layers; for example, it can be one of 1, 2, 3, or 4 layers or any value between two or more, preferably 2-3 layers.

[0062] In this application, the number of stacked layers in 3D printing affects the expansion behavior of 3D printed mesh in supercritical fluid. When the number of stacked layers in 3D printing is 1-4, it is beneficial for cell nucleation and uniform foaming, resulting in 3D printed foamed mesh with high tensile and tear strength, and large-diameter cells (average diameter of 50-100μm) and small-diameter cells (average diameter of 1-30μm) in the lines. When the number of stacked layers in 3D printing is 2-3, the 3D printed mesh will preferentially expand in the thickness direction during the foaming process, reducing the expansion in the length and width directions, thereby improving the tensile and tear strength of the 3D printed foamed mesh.

[0063] Specifically, the soaking temperature is 10-50℃, for example, it can be a range of one or any two of 10℃, 12℃, 15℃, 17℃, 20℃, 23℃, 25℃, 28℃, 30℃, 32℃, 35℃, 37℃, 40℃, 43℃, 45℃, 48℃, and 50℃, preferably 20-40℃.

[0064] Specifically, the soaking time is 1-30 min, for example, it can be one or any two of the following: 1 min, 3 min, 5 min, 7 min, 9 min, 11 min, 13 min, 15 min, 17 min, 19 min, 21 min, 23 min, 25 min, 28 min, 30 min.

[0065] In this application, the temperature and time of solvent immersion affect the performance of 3D printed foamed mesh. Specifically, if the solvent immersion temperature is too low, more surface defects will remain on the sample surface, affecting the subsequent foaming process and further causing a rapid decrease in tensile and tear strength. If the solvent immersion temperature is too high, the interfacial bonding performance will decrease, resulting in a rapid decrease in tensile and tear strength.

[0066] In some embodiments, the volume ratio of the alcohol to acetone is (70:30) to (50:50); for example, it can be a range of one or any two of 70:30, 65:35, 60:40, 55:45, and 50:50; preferably (65:35) to (55:45).

[0067] In this application, an excessively high acetone content will cause the surface of the 3D printed foamed mesh to collapse and the interface to delaminate severely. When the volume ratio of alcohol to acetone is (65:35) to (55:45), it is beneficial to adjust the dissolution effect, improve the interface adhesion of the 3D printed foamed mesh, and thus improve the tensile strength and tear strength of the 3D printed foamed mesh.

[0068] In some embodiments, the antioxidant is a phosphite antioxidant, such as tris(2,4-di-tert-butylphenyl) phosphite, bis[2-methyl-4,6-bis(1,1'-dimethylethyl)phenol] ethyl phosphate, tetrakis(2,4-di-tert-butyloctakoxy-4,4-biphenyl) phosphate, bis(2,4-di-tert-butylphenyl) pentaerythritol diphosphite, (2,4,6-tri-tert-butylphenyl-2- At least one of the following: butyl-2-ethyl)-1,3-propanediol phosphite, di(2,4-di-p-isopropylphenyl)pentaerythritol bisphosphite, 2,2'-ethylidene bis(4,6-di-tert-butylphenyl) fluorophosphite, tetrakis(2,4-di-tert-butylphenyl-4,4-biphenyl) bisphosphite, spiroethylene glycol di[2,2'-methylene bis(4,6-di-tert-butylphenyl)] phosphite, and trinonylphenyl phosphite.

[0069] In this application, phosphite stabilizers can reduce the probability of oxidative decomposition of elastomer materials during repeated heat processing, thereby improving the mechanical properties of 3D printed foamed mesh fabric.

[0070] In some embodiments, the alcohol includes at least one of a monohydric alcohol and / or a polyhydric alcohol.

[0071] Specific examples of monohydric alcohols include at least one of ethanol, propanol, butanol, and pentanol.

[0072] Polyols include at least one of diols and triols; specific examples of diols include at least one of ethylene glycol, 1,2-propanediol, 1,4-butanediol, 1,6-hexanediol, neopentyl glycol, and diethylene glycol; specific examples of triols include at least one of glycerol and trimethylolpropane.

[0073] Preferably, the alcohol is a monohydric alcohol; in this application, when the alcohol is a monohydric alcohol, it is beneficial to improve the tensile strength and tear strength of the 3D printed foam mesh.

[0074] In some embodiments, the actual density of the 3D printed mesh is 0.7-1.1 g / cm³. 3 For example, it could be 0.7 g / cm³. 3 0.75 g / cm 3 0.8 g / cm 3 0.85 g / cm 3 0.9 g / cm 3 0.95 g / cm 3 1 g / cm 3 1.05 g / cm 3 1.1 g / cm 3 The range of values ​​between one or any two of them.

[0075] In this application, the actual density of the 3D printed mesh affects the performance of the 3D printed foamed mesh. If the actual density of the 3D printed mesh is too low, it will cause a rapid decrease in tensile and tear strength. If the actual density of the 3D printed mesh is too high, it will cause poor interfacial adhesion and a rapid decrease in tear strength.

[0076] In some embodiments, the melt extrusion temperature is 90-190°C; melt extrusion at this temperature ensures that the foaming agent in the thermoplastic resin mixture will not foam.

[0077] In some embodiments, the 3D printing temperature is 200-230°C. 3D printing at this temperature allows the thermoplastic resin composite material to melt, expand, and foam, resulting in a pre-foamed 3D printed mesh.

[0078] In some embodiments, the supercritical fluid impregnation temperature is 80-180°C, for example, it can be a range of one or any two of 80°C, 90°C, 100°C, 110°C, 120°C, 130°C, 140°C, 150°C, 160°C, 170°C, and 180°C; preferably 100-150°C; the pressure is 10-30 MPa, for example, it can be a range of one or any two of 10 MPa, 12 MPa, 15 MPa, 18 MPa, 20 MPa, 23 MPa, 25 MPa, 28 MPa, and 30 MPa, preferably 15-25 MPa; the time is 0.3-1 h, for example, it can be a range of one or any two of 0.1 h, 0.2 h, 0.3 h, 0.4 h, 0.5 h, 0.6 h, 0.7 h, 0.8 h, 0.9 h, and 1 h; preferably 0.2-0.8 h.

[0079] In some embodiments, the supercritical fluid includes at least one of CO2 fluid and N2 fluid.

[0080] In some embodiments, the solubility of the supercritical fluid in the 3D printed foamed mesh is 0.5-8%; for example, it can be a range of one or any two of 0.5%, 0.8%, 1%, 1.2%, 1.5%, 1.7%, 2%, 3%, 4%, 5%, 6%, 7%, 7.3%, 7.5%, 7.8%, 8%; preferably 0.8-5%.

[0081] In this application, the solubility of the supercritical fluid in the 3D printed foamed mesh can be controlled by adjusting the pressure and temperature of the supercritical fluid impregnation. The solubility (%) of the supercritical fluid in the 3D printed foamed mesh is (m2-m1)×100% / m1, where m1 is the mass of the 3D printed mesh and m2 is the mass of the 3D printed foamed mesh.

[0082] During supercritical foaming, the plasticizing effect of the supercritical fluid lowers the softening point of the polymer. Prolonged supercritical fluid immersion can cause the 3D printed mesh to creep under its own gravity. By controlling the solubility of the supercritical fluid, the temperature and time of supercritical fluid immersion, the 3D printed mesh can be prevented from creeping during supercritical fluid immersion and foaming, resulting in 3D printed foamed mesh with good tensile strength, tear strength, and uniform foaming.

[0083] As a foaming method, foaming can be carried out by depressurization foaming or heating foaming; it can also be carried out by introducing a heat medium, which can be air or hot water steam.

[0084] Specifically, the depressurization rate of the depressurization foam is 50-100 MPa / s, for example, but not limited to 50 MPa / s, 60 MPa / s, 70 MPa / s, 80 MPa / s, 90 MPa / s, and 100 MPa / s.

[0085] In some implementations, at least one of the following conditions is met:

[0086] (a) The thermoplastic elastomer includes at least one of polyurethane (TPU), thermoplastic polyester elastomer (TPEE), polyamide, hydrogenated styrene-butadiene block copolymer (SEBS), ethylene-vinyl acetate copolymer (EVA), polyolefin elastomer (POE), and olefin block copolymer (OBC);

[0087] Specifically, thermoplastic polyester elastomers refer to linear block copolymers containing polybutylene terephthalate (PBT) polyester hard segments and aliphatic polyester or polyether soft segments.

[0088] Specifically, examples of polyamides include PA6, PA12, PA66, PA610, PA612, PA6I, PA6T, and PEBA (polyether amide block copolymer).

[0089] (b) The foaming agent comprises at least one of CO2 fluid, N2 fluid, flammable alkane, azodicarbonamide, carbonate, and N,N-dinitrospentamethylenetetramine;

[0090] (c) The nucleating agent includes at least one of calcium carbonate, talc, mica, montmorillonite, nano silica, carbon black, and carbon nanotubes;

[0091] (d) The color masterbatch includes organic dyes;

[0092] (e) The matte agent comprises at least one of sorbitol monopalmitate and xylitol ester;

[0093] (f) The lubricant includes at least one of polyethylene wax, stearic acid, lead stearate, zinc stearate, and paraffin wax;

[0094] (g) The melt mass flow rate of the thermoplastic elastomer at 210°C and 2.16 kg is 0.2-12 g / 10 min; for example, it can be one of or between any two of the following values: 0.2 g / 10 min, 0.5 g / 10 min, 1 g / 10 min, 2 g / 10 min, 3 g / 10 min, 4 g / 10 min, 5 g / 10 min, 6 g / 10 min, 7 g / 10 min, 8 g / 10 min, 9 g / 10 min, 10 g / 10 min, 11 g / 10 min, and 12 g / 10 min.

[0095] The production method of the thermoplastic resin composite material of this application is not particularly strictly limited, and blending equipment such as a mixer is used. The order of addition of components is not particularly strictly limited; they can be added simultaneously or in a certain order. Two or more components can be selected from all components for pre-mixing. For example, color masterbatch, matting agent, and lubricant can be pre-formed into masterbatch, and then added to other components in a set proportion for mixing. The resin used in the masterbatch can be the thermoplastic elastomer described in this application.

[0096] In some embodiments, the 3D printing planning path includes at least one of the following: mesh structure, tetrahedral structure, linear structure, triangular structure, internal hexagonal structure, cube structure, cube partitioned structure, octagonal structure, concentric circle structure, zigzag structure, intersecting structure, intersecting 3D structure, spiral icosahedral structure, lightning bolt structure, and reinforced border. The mesh structure includes at least one of in-plane mesh structure and interlayer mesh structure. In the specific embodiments of this application, the above structures are all structures included in the 3D printing software.

[0097] This application aims to fabricate planar three-dimensional parts suitable for shoe uppers, but since molten filaments are extruded, stacking of these filaments is necessary. When the molten filaments are stacked using an in-plane mesh structure to form a plane, it improves breathability, and the connection points between the molten filaments also enhance the tensile strength of the entire part. Furthermore, since 3D printing is essentially a layer-by-layer stacking process, setting up a mesh structure between layers in the planned printing path further improves breathability and reduces true density.

[0098] In a second aspect, this application provides a 3D printed foamed mesh fabric, which is prepared by the method for preparing the 3D printed foamed mesh fabric.

[0099] In some embodiments, the areal density of the 3D printed foamed mesh is 100-800 g / m². 2 The tensile strength is ≥10kgf and the tear strength is ≥5kgf. The lines of the 3D printed foamed mesh have large-diameter cells and small-diameter cells. The average diameter of the large-diameter cells is 50-100μm and the average diameter of the small-diameter cells is 1-30μm.

[0100] Specifically, the areal density of the 3D printed foamed mesh can be 100 g / m². 2 200g / m 2 300g / m 2 400g / m 2 500g / m 2 600g / m 2 700g / m 2 800g / m 2 The range of values ​​between one or any two of them;

[0101] Specifically, the tensile strength of the 3D printed foamed mesh can be one of 10 kgf, 12 kgf, 15 kgf, 17 kgf, 20 kgf, 23 kgf, 25 kgf or any two of these values.

[0102] Specifically, the tear strength of the 3D printed foamed mesh can be a value in the range of one or any two of 5 kgf, 7 kgf, 9 kgf, 11 kgf, 13 kgf, and 15 kgf.

[0103] Specifically, the average diameter of the large-diameter cells in the lines of the 3D printed foamed mesh can be one of 50μm, 60μm, 70μm, 80μm, 90μm, 100μm or any value between two of them.

[0104] Specifically, the average diameter of the large-diameter cells in the lines of the 3D printed foamed mesh can be a value in the range of one or any two of 1μm, 5μm, 10μm, 15μm, 20μm, 25μm, and 30μm.

[0105] Specifically, the areal density of the 3D printed foamed mesh is tested using the following method: A 3D printed foamed mesh with a length and width of 20cm is weighed, and the weight per unit area, i.e., the areal density (g / m²), is obtained by dividing the weight by the area. 2 ).

[0106] Specifically, the tensile strength and tear strength of the 3D printed foamed mesh fabric were tested using the following methods: 1. Tensile strength test - The mesh fabric was cut into strips with a length and width of 15cm and 2cm respectively, clamped on a fixture with a spacing of 75cm, and stretched at a speed of 300mm / min until the sample broke. The maximum force during the test was recorded as the tensile strength (kgf); 2. Tear strength test - The mesh fabric was cut into a trouser-shaped tear sample with a length and width of 21cm and 75cm respectively, and a notch length of 75cm. The two sides of the notch were clamped on the upper and lower sides of the fixture respectively, and then stretched at a test speed of 200mm / min until the notch extended to the remaining 1 / 3 position. The maximum force during the test was recorded as the tear strength (kgf).

[0107] Specifically, the average diameter of the cells in the lines of the 3D printed foamed mesh is obtained by the following method: the micromorphology of the cells in the cross-section of the lines is observed by scanning electron microscopy, and the average diameter of the cells is obtained by statistically analyzing the distribution of cell diameters and then using Gaussian fitting.

[0108] In a third aspect, this application provides a shoe upper comprising the aforementioned 3D-printed foamed mesh fabric.

[0109] The raw materials used in the embodiments and comparative examples are described below, but are not limited to these materials:

[0110] Thermoplastic elastomer A: Polyether-type TPU, Shore hardness 80A, WHT-8180, Wanhua Chemical;

[0111] Thermoplastic elastomer B: Polyether-type TPU, Shore hardness 70A, WHT-8170, Wanhua Chemical;

[0112] Thermoplastic elastomer C: Polyether-type TPU, Shore hardness 60A, 1160 A 13 P000, BASF, Germany;

[0113] Thermoplastic elastomer D: Polyether-type TPU, Shore hardness 50A, SP1150 A 19P, BASF, Germany;

[0114] Thermoplastic elastomer E: Polyester-type TPU, Shore hardness 60A, WHT-1560, Wanhua Chemical;

[0115] Thermoplastic elastomer F: TPEE, Shore hardness 80A, Arnitel EL150, DSM Netherlands;

[0116] Thermoplastic elastomer G: EVA, Shore hardness 60A, 40L-03, Dow Chemical;

[0117] Thermoplastic elastomer H: Polyether-type TPU, Shore hardness 45A, SP 1145 A 12PU, BASF, Germany;

[0118] Thermoplastic elastomer I: Polyether-type TPU, Shore hardness 90A, WHT-8190, Wanhua Chemical;

[0119] Foaming agent: Sodium bicarbonate, commercially available;

[0120] Color masterbatch: Polybatc, Clariant, commercially available;

[0121] Matte finish: Sorbitol monopalmitate, commercially available

[0122] Lubricant: Zinc stearate, commercially available;

[0123] Antioxidant: Tris(2,4-di-tert-butylphenyl) phosphite, commercially available.

[0124] Example 1

[0125] This embodiment provides a method for preparing 3D printed foamed mesh fabric, including the following steps:

[0126] S1: Add 80 parts by weight of thermoplastic elastomer A, 5 parts by weight of foaming agent, 5 parts by weight of color masterbatch, 5 parts by weight of matting agent, 2 parts by weight of lubricant, 0.5 parts by weight of nucleating agent and 0.3 parts by weight of antioxidant A into a mixer and mix evenly to obtain thermoplastic resin composite material.

[0127] The thermoplastic resin composite material is added to a single-screw extruder for melt extrusion to obtain filaments; the melt extrusion temperature is 190℃.

[0128] The obtained filament material is 3D printed according to the planned path to obtain 3D printed mesh fabric; the 3D printing parameters are as follows: 2 stacked layers, printing temperature 220℃;

[0129] S2: The 3D printed mesh obtained in step S1 is placed in a solvent and soaked at 20°C for 10 minutes. After washing and drying, a pretreated 3D printed mesh is obtained. The solvent is a mixture of ethanol and acetone, with a volume ratio of ethanol to acetone of 65:35.

[0130] S3: The pretreated 3D printing mesh is placed in an autoclave and impregnated with nitrogen fluid. The resulting impregnated 3D printing mesh is depressurized and foamed within 1 second to obtain a 3D printed foamed mesh. The impregnation temperature is 140℃, the pressure is 18MPa, the time is 0.5h, and the solubility of nitrogen fluid in the 3D printed foamed mesh is 1%.

[0131] Example 2

[0132] This embodiment provides a method for preparing 3D printed foamed mesh fabric. The difference between the other embodiments is that thermoplastic elastomer B is used instead of thermoplastic elastomer A.

[0133] Example 3

[0134] This embodiment provides a method for preparing 3D printed foamed mesh fabric. The difference between the other embodiments is that thermoplastic elastomer C is used instead of thermoplastic elastomer A.

[0135] Example 4

[0136] This embodiment provides a method for preparing 3D printed foamed mesh fabric. The difference between the other embodiments is that thermoplastic elastomer D is used instead of thermoplastic elastomer A.

[0137] Example 5

[0138] This embodiment provides a method for preparing 3D printed foamed mesh fabric. The difference between the other embodiments is that thermoplastic elastomer E is used instead of thermoplastic elastomer A.

[0139] Example 6

[0140] This embodiment provides a method for preparing 3D printed foamed mesh fabric. The difference between the other embodiments is that thermoplastic elastomer F is used instead of thermoplastic elastomer A.

[0141] Example 7

[0142] This embodiment provides a method for preparing 3D printed foamed mesh fabric. The difference between the other embodiments is that thermoplastic elastomer G is used instead of thermoplastic elastomer A.

[0143] Example 8

[0144] This embodiment provides a method for preparing 3D printed foamed mesh fabric. The difference between this embodiment and the other embodiment 1 is that the number of stacked layers in the 3D printing is 1.

[0145] Example 9

[0146] This embodiment provides a method for preparing 3D printed foamed mesh fabric. The difference between this embodiment and the other embodiment 1 is that the number of stacked layers in the 3D printing is 3.

[0147] Example 10

[0148] This embodiment provides a method for preparing 3D printed foamed mesh fabric. The difference between this embodiment and the other embodiment 1 is that the number of stacked layers in the 3D printing is 4.

[0149] Example 11

[0150] This embodiment provides a method for preparing 3D printed foamed mesh fabric, which differs from Example 1 in that the mass ratio of ethanol to acetone is 55:45.

[0151] Example 12

[0152] This embodiment provides a method for preparing 3D printed foamed mesh, which differs from Example 1 in that the mass ratio of ethanol to acetone is 50:50.

[0153] Example 13

[0154] This embodiment provides a method for preparing 3D printed foamed mesh fabric, which differs from Example 1 in that the mass ratio of ethanol to acetone is 70:30.

[0155] Example 14

[0156] This embodiment provides a method for preparing 3D printed foamed mesh fabric, including the following steps:

[0157] S1: Add 75 parts by weight of thermoplastic elastomer A, 0.1 parts by weight of foaming agent, 10 parts by weight of color masterbatch, 0.1 parts by weight of matting agent, 5 parts by weight of lubricant, 1 part by weight of nucleating agent and 0.1 parts by weight of antioxidant A into a mixer and mix evenly to obtain thermoplastic resin composite material.

[0158] The thermoplastic resin composite material is added to a single-screw extruder for melt extrusion to obtain filaments; the melt extrusion temperature is 190℃.

[0159] The obtained filament material is 3D printed according to the planned path to obtain 3D printed mesh fabric; the 3D printing parameters are as follows: 2 stacked layers, printing temperature 220℃;

[0160] S2: The 3D printed mesh obtained in step S1 is placed in a solvent and soaked at 10°C for 10 minutes. Then it is washed and dried to obtain a pretreated 3D printed mesh. The solvent is a mixture of ethanol and acetone, with a volume ratio of 70:30.

[0161] S3: The pretreated 3D printing mesh is placed in an autoclave and impregnated with nitrogen fluid. The resulting impregnated 3D printing mesh is depressurized and foamed within 1 second to obtain a 3D printed foamed mesh. The impregnation temperature is 150℃, the pressure is 18MPa, the time is 0.2h, and the solubility of nitrogen fluid in the 3D printed foamed mesh is 1.2%.

[0162] Example 15

[0163] This embodiment provides a method for preparing 3D printed foamed mesh fabric, including the following steps:

[0164] S1: Add 90 parts by weight of thermoplastic elastomer A, 10 parts by weight of foaming agent, 1 part by weight of color masterbatch, 10 parts by weight of matting agent, 0.1 parts by weight of lubricant, 0.1 parts by weight of nucleating agent and 0.5 parts by weight of antioxidant A into a mixer and mix evenly to obtain thermoplastic resin composite material.

[0165] The thermoplastic resin composite material is added to a single-screw extruder for melt extrusion to obtain filaments; the melt extrusion temperature is 190℃.

[0166] The obtained filament melt was 3D printed according to the planned path to obtain a 3D printed mesh; the 3D printing parameters are as follows: 2 stacked layers, printing temperature 220℃;

[0167] S2: The 3D printed mesh obtained in step S1 is placed in a solvent and soaked at 50°C for 10 minutes. Then it is washed and dried to obtain a pretreated 3D printed mesh. The solvent is a mixture of ethanol and acetone, with a volume ratio of 70:30.

[0168] S3: The pretreated 3D printing mesh is placed in an autoclave and impregnated with nitrogen fluid. The resulting impregnated 3D printing mesh is depressurized and foamed within 1 second to obtain a 3D printed foamed mesh. The impregnation temperature is 100℃, the pressure is 18MPa, the time is 1h, and the solubility of nitrogen fluid in the 3D printed foamed mesh is 0.6%.

[0169] Comparative Example 1

[0170] This comparative example provides a method for preparing 3D printed foamed mesh fabric, which differs from Example 1 in that it does not include step S2.

[0171] Comparative Example 2

[0172] This comparative example provides a method for preparing 3D printed foamed mesh, which differs from Example 1 in that: in step S1, thermoplastic elastomer H is used instead of thermoplastic elastomer A.

[0173] Comparative Example 3

[0174] This comparative example provides a method for preparing 3D printed foamed mesh, which differs from Example 1 in that: in step S1, thermoplastic elastomer I is used instead of thermoplastic elastomer A.

[0175] Comparative Example 4

[0176] This comparative example provides a method for preparing 3D printed foamed mesh fabric, which differs from Example 1 in that: the thermoplastic resin composite material includes the following raw materials in parts by weight: 85 parts by weight of thermoplastic elastomer A, 5 parts by weight of color masterbatch, 5 parts by weight of matting agent, 2 parts by weight of lubricant, 0.5 parts by weight of nucleating agent and 0.3 parts by weight of antioxidant A, that is, the thermoplastic resin composite material does not contain foaming agent.

[0177] Comparative Example 5

[0178] This comparative example provides a method for preparing 3D printed foamed mesh, which differs from Example 1 in that: in step S1, the number of stacked layers in 3D printing is 5.

[0179] Comparative Example 6

[0180] This comparative example provides a method for preparing 3D printed foamed mesh fabric, which differs from Example 1 in that the mass ratio of ethanol to acetone is 80:20.

[0181] Comparative Example 7

[0182] This comparative example provides a method for preparing 3D printed foamed mesh fabric, which differs from Example 1 in that the mass ratio of ethanol to acetone is 40:60.

[0183] Comparative Example 8

[0184] This comparative example provides a method for preparing 3D printed foamed mesh fabric, which differs from Example 1 in that the soaking temperature is 5°C.

[0185] Comparative Example 9

[0186] This comparative example provides a method for preparing 3D printed foamed mesh fabric, which differs from Example 1 in that the soaking temperature is 60°C.

[0187] Performance testing

[0188] The 3D printed mesh and 3D printed foamed mesh obtained in the examples and comparative examples were subjected to performance tests, and the test methods are as follows:

[0189] (1) True density: obtained by testing with a densitometer;

[0190] (2) Thickness: obtained by thickness gauge;

[0191] (3) Surface density: Take a 10cm×10cm square piece, weigh it and calculate the surface density (g / m³). 2 );

[0192] (4) Average diameter of the bubble: The average diameter of the bubble was obtained by scanning electron microscopy. The diameters of 100 large bubbles and 100 small bubbles were counted and the average value was calculated.

[0193] (5) Tensile strength: The tensile strength was determined by using a universal testing machine and stretching the material at a speed of 300 mm / min until it broke. The maximum force tested was taken as the tensile strength.

[0194] (6) Tear strength: Using a universal testing machine, the trouser-shaped tear sample was stretched at a speed of 200 mm / min until 1 / 3 of the notch remained, and the maximum force was taken as the tear strength;

[0195] (7) Appearance: Visual inspection.

[0196] The test results are shown in Table 1.

[0197] Table 1

[0198]

[0199] As shown in Table 1, the actual density of the 3D-printed foamed mesh fabric in this application is ≤0.9 g / cm³. 3 Thickness ≤ 1.3mm, surface density ≤ 800g / m³ 2 The tensile strength is ≥10kgf and the tear strength is ≥5kgf. The lines of the 3D printed foamed mesh have large-diameter and small-diameter cells. The average diameter of the large-diameter cells is 50-100μm and the average diameter of the small-diameter cells is 1-30μm.

[0200] The experimental data from Examples 1-5 and Comparative Examples 2-3 show that when the Shore hardness of the thermoplastic elastomer is 60A-70A, the tensile strength of the obtained 3D printed foamed mesh is ≥17kgf and the tear strength is ≥7kgf. This indicates that when the Shore hardness of the thermoplastic elastomer is 60A-70A, the tensile strength and tear strength of the 3D printed foamed mesh can be improved.

[0201] Experimental data from Examples 1, 8-10, and Comparative Example 5 show that when the number of stacked layers in 3D printing is 2-3, the tensile strength of the resulting 3D printed foamed mesh is ≥15.2 kgf, and the tear strength is ≥6.4 kgf. This indicates that having 2-3 stacked layers in 3D printing can improve the tensile and tear strength of the 3D printed foamed mesh.

[0202] Experimental data from Examples 1, 11-13, and Comparative Examples 6-7 show that when the volume ratio of monohydric alcohol to acetone is (65:35)-(55:45), the tensile strength of the resulting 3D printed foamed mesh is ≥15kgf and the tear strength is ≥6kgf. This indicates that when the volume ratio of monohydric alcohol to acetone is (65:35)-(55:45), the tensile strength and tear strength of the 3D printed foamed mesh can be improved.

[0203] The experimental data from Example 1 and Comparative Examples 8-9 show that when the solvent immersion temperature is less than 10°C or greater than 50°C, the tensile strength of the obtained 3D printed foamed mesh is ≤8kgf and the tear strength is ≤4.2kgf. This indicates that the solvent immersion temperature must be between 10-50°C to obtain 3D printed foamed mesh with high tensile and tear strength.

[0204] Figure 2 This is an appearance diagram of the 3D printed foamed mesh fabric of Example 1; Figure 3 This is an image showing the appearance of the 3D-printed foamed mesh fabric in Comparative Example 1. From... Figure 2 and Figure 3 As can be seen from the above, the surface of the 3D printed foamed mesh prepared in this application is uniform, while the surface of the 3D printed foamed mesh prepared in Comparative Example 1 is rough and has many bulges.

[0205] Finally, it should be noted that the above embodiments are used to illustrate the technical solutions of this disclosure and not to limit the scope of protection of this disclosure. Although this disclosure has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can be made to the technical solutions of this disclosure without departing from the substance and scope of the technical solutions of this disclosure.

Claims

1. A method for preparing 3D printed foamed mesh fabric, characterized in that, Includes the following steps: S1: Add the thermoplastic resin mixture to a single-screw extruder for melt extrusion to obtain a thermoplastic resin composite material; 3D print the thermoplastic resin composite material to obtain a 3D printed mesh; wherein the number of stacked layers in the 3D printing is 1-4 layers; S2: Immerse the 3D printed mesh in a solvent, then wash and dry it to obtain a pretreated 3D printed mesh; wherein the solvent is a mixture of alcohol and acetone, and the immersion temperature is 10-50℃; the volume ratio of the alcohol and acetone is (70:30)-(50:50). S3: After impregnating the pretreated 3D printed mesh with supercritical fluid, it is foamed to obtain 3D printed foamed mesh. The thermoplastic resin mixture comprises the following raw materials in parts by weight: 75-90 parts thermoplastic elastomer, 0.1-10 parts foaming agent, 1-10 parts color masterbatch, 0.1-10 parts matting agent, 0.1-5 parts lubricant, 0.1-1 part nucleating agent, and 0.1-0.5 parts antioxidant; The Shore hardness of the thermoplastic elastomer is 50A-80A.

2. The method for preparing 3D printed foamed mesh fabric as described in claim 1, characterized in that, The 3D printing process involves stacking 2-3 layers.

3. The method for preparing 3D printed foamed mesh fabric as described in claim 1, characterized in that, The volume ratio of the alcohol to acetone is (65:35) to (55:45).

4. The method for preparing 3D printed foamed mesh fabric as described in claim 1, characterized in that, The antioxidant is a phosphite antioxidant.

5. The method for preparing 3D printed foamed mesh fabric as described in claim 1, characterized in that, In step S2, the soaking temperature is 20-40℃ and the soaking time is 1-30 minutes.

6. The method for preparing 3D printed foamed mesh fabric as described in claim 1, characterized in that, In step S2, the alcohol includes at least one of monohydric alcohols and polyhydric alcohols.

7. The method for preparing 3D printed foamed mesh fabric as described in claim 1, characterized in that, In step S2, the actual density of the 3D printed mesh is 0.7-1.1 g / cm³. 3 .

8. The method for preparing 3D printed foamed mesh fabric as described in claim 1, characterized in that, The supercritical fluid impregnation temperature is 80-180℃, the pressure is 10-30MPa, and the time is 0.1-1.0h.

9. The method for preparing 3D printed foamed mesh fabric as described in claim 1, characterized in that, The supercritical fluid includes at least one of CO2 fluid and N2 fluid.

10. The method for preparing 3D printed foamed mesh fabric as described in claim 1, characterized in that, The solubility of the supercritical fluid in the 3D printed foamed mesh is 0.5-8%; the solubility (%) of the supercritical fluid in the 3D printed foamed mesh is (m2-m1)×100% / m1; where m1 is the mass of the 3D printed mesh and m2 is the mass of the 3D printed foamed mesh.

11. The method for preparing 3D printed foamed mesh fabric as described in claim 1, characterized in that, At least one of the following conditions must be met: (a) The thermoplastic elastomer includes at least one of thermoplastic polyurethane, thermoplastic polyester elastomer, polyether amide block copolymer, hydrogenated styrene-butadiene block copolymer, ethylene-vinyl acetate copolymer, polyolefin elastomer, and olefin block copolymer; (b) The foaming agent comprises at least one of CO2 fluid, N2 fluid, flammable alkane, azodicarbonamide, carbonate, and N,N-dinitrospentamethylenetetramine; (c) The nucleating agent includes at least one of calcium carbonate, talc, mica, montmorillonite, nano silica, carbon black, and carbon nanotubes; (d) The color masterbatch includes organic dyes; (e) The matte agent comprises at least one of sorbitol monopalmitate and xylitol ester; (f) The lubricant includes at least one of polyethylene wax, stearic acid, lead stearate, zinc stearate, and paraffin wax; (g) The melt mass flow rate of the thermoplastic elastomer at 210°C and 2.16 kg is 0.2-12 g / 10 min.

12. A 3D-printed foamed mesh fabric, characterized in that, It is prepared by the method for preparing 3D printed foamed mesh fabric according to any one of claims 1-11.

13. The 3D printed foamed mesh fabric as described in claim 12, characterized in that, The areal density of the 3D printed foamed mesh is 100-800 g / m². 2 The tensile strength is ≥10kgf and the tear strength is ≥5kgf. The lines of the 3D printed foamed mesh have large-diameter cells and small-diameter cells. The average diameter of the large-diameter cells is 50-100μm and the average diameter of the small-diameter cells is 1-30μm.

14. A shoe upper, characterized in that, Includes the 3D printed foamed mesh fabric as described in claim 12 or 13.

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