Polymer foam product and method of making and shoe material

Abstract

The application provides a polymer foam product and a preparation method and a shoe material thereof, and belongs to the technical field of 3D printing. Firstly, a thermoplastic resin mixture is melt-extruded, and the obtained thermoplastic resin composite material is 3D printed according to a planned path to obtain a polymer product; secondly, the polymer product is soaked in a solvent; finally, the polymer product after soaking is impregnated with a supercritical fluid, and then foaming is performed to obtain a polymer foam product. The polymer foam product prepared by the method provided in the application has low apparent density, high compressive permanent set, high resilience and high tensile strength.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of 3D printing, in particular to a polymer foam product and a preparation method thereof and a shoe material. BACKGROUND

[0002] 3D printing is a kind of rapid prototyping technology, which is a technology that uses thermoplastic, nylon, resin, rubber, metal powder and other bondable materials to construct objects through additive printing based on digital model files. 3D printing technology is used for shoe soles, which breaks the shackles of molds, can print various complex-shaped soles, realizes product diversification, improves product competitiveness, and can save processes, and has been favored by shoe enterprises in recent years and has become a research and development direction of shoe enterprises. Although the rapid manufacturing and personalized customization of shoes are realized through 3D printing, the density of the printed soles is generally high, the material is hard, the softness is poor, and the wearing experience is not strong.

[0003] Lightweight of shoe material has been one of the goals pursued by major sports brands. In the field of sports shoes, foam materials are one of the ways to achieve lightweight of shoe materials and are widely used in shoe soles. Among them, supercritical fluid foaming is a green and environmentally friendly foaming technology, and the production process is free of harmful substances and other production or residues. At present, it has been used for the preparation of shoe materials. The combination of customized 3D printing technology and lightweight foaming technology is expected to realize the preparation of ultra-light soles. However, foaming after forming polymer parts will seriously affect the surface quality and expansion uniformity of the final shoe material, resulting in a decrease in its rebound performance and compression deformation performance, and foaming after 3D printing will change the size, shape and other parameters of the obtained parts, resulting in a decrease in the size accuracy of the printed parts. SUMMARY

[0004] The purpose of the present disclosure is to overcome the shortcomings of the prior art and provide a polymer foam product, a preparation method thereof and a shoe material.

[0005] To achieve the above-mentioned purpose, the technical scheme adopted by the present disclosure is as follows: in the first aspect, a preparation method of a polymer foam product is provided, comprising the following steps:

[0006] S1: melt-extruding a thermoplastic resin mixture into a single-screw extruder to obtain a thermoplastic resin composite; 3D printing the thermoplastic resin composite to obtain a polymer part; wherein the thickness of the crystal lattice of the polymer part is 0.5-5mm;

[0007] S2: soaking the polymer piece in a solvent, then washing, drying to obtain a pretreated polymer piece; wherein the solvent is a mixture of alcohol and acetone, the soaking temperature is 10-50℃; the volume ratio of the alcohol and acetone is (45:55)-(25:75);

[0008] S3: after the pretreated polymer piece is immersed in a supercritical fluid, foaming is performed to obtain a polymer foam product;

[0009] The thermoplastic resin mixture includes the following raw materials by weight: 75-90 parts of thermoplastic elastomer resin, 0-5 parts of foaming agent, 1-10 parts of color master, 0.1-10 parts of matte agent, 0.1-5 parts of lubricant, 0.1-1 parts of nucleating agent, and 0.1-0.5 parts of antioxidant.

[0010] The Shore hardness of the thermoplastic elastomer resin is 85A-95A.

[0011] In some embodiments, the thickness of the polymer piece lattice is 1-3mm.

[0012] In some embodiments, the alcohol includes at least one of monohydric alcohol and polyhydric alcohol.

[0013] In some embodiments, the antioxidant is a hindered amine antioxidant.

[0014] In some embodiments, in step S2, the soaking temperature is 20-40℃, and the time is 1-30min.

[0015] In some embodiments, the volume ratio of the alcohol and acetone is (40:60)-(30:70).

[0016] In some embodiments, the supercritical fluid immersion temperature is 10-180℃, the pressure is 10-30MPa, and the time is 0.3-12h.

[0017] In some embodiments, the supercritical fluid includes at least one of CO2 fluid and N2 fluid.

[0018] In some embodiments, the solubility of the supercritical fluid in the polymer foam product is 0.5-8%.

[0019] In some embodiments, at least one of the following conditions is met:

[0020] (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;

[0021] (b) The foaming agent comprises at least one of CO2 fluid, N2 fluid, flammable alkane, azodicarbonamide, carbonate, and N,N-dinitrospentamethylenetetramine;

[0022] (c) The nucleating agent includes at least one of calcium carbonate, talc, mica, montmorillonite, nano silica, carbon black, and carbon nanotubes;

[0023] (d) The color masterbatch includes organic dyes;

[0024] (e) The matte agent comprises at least one of sorbitol monopalmitate and xylitol ester;

[0025] (f) The lubricant includes at least one of polyethylene wax, stearic acid, lead stearate, zinc stearate, and paraffin.

[0026] Secondly, a polymer foam product is provided, which is prepared by the method for preparing the polymer foam product.

[0027] In some embodiments, the apparent density of the polymer foam product is 100-300 kg / m³. 3 Rebound rate ≥60%, compression set ≤50%.

[0028] Thirdly, a footwear material is provided, including the aforementioned polymer foam product.

[0029] Compared with the prior art, the beneficial effects of this disclosure are as follows: In the 3D printing process of this application, the thermoplastic resin composite material is melt-extruded and stacked in the form of filaments or granules. During the melt extrusion process, the melt containing the foaming agent is pre-foamed to obtain a pre-foamed polymer part. There are pores and gaps in the lattice units of the polymer part. By immersing the polymer part in a solvent, the defects in the lattice structure of the polymer part are eliminated while maintaining structural and dimensional stability. This reduces the probability of surface bubbles forming in the polymer part during the foaming process after being impregnated with supercritical fluid. At the same time, it reduces the apparent density and compression set of the polymer foam product while improving the resilience and tensile properties of the polymer foam product. Detailed Implementation

[0030] 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.

[0031] As used in this article:

[0032] "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.

[0033] 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.

[0034] 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.

[0035] In these embodiments, unless otherwise specified, the portions and percentages are all by weight.

[0036] "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.

[0037] "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).

[0038] In a first aspect, this application provides a method for preparing a polymer foam product, comprising the following steps:

[0039] 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 polymer part; wherein the thickness of the polymer part lattice is 0.5-5mm;

[0040] S2: The polymer part is immersed in a solvent, then washed and dried to obtain a pretreated polymer part; 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 (45:55)-(25:75).

[0041] S3: After impregnating the pretreated polymer parts with supercritical fluid, foaming is performed to obtain polymer foam products;

[0042] The thermoplastic resin mixture comprises the following raw materials in parts by weight: 75-90 parts thermoplastic elastomer resin, 0-5 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;

[0043] The thermoplastic elastomer resin has a Shore hardness of 85A-95A.

[0044] In the 3D printing process of this application, thermoplastic resin composite materials are melt-extruded and stacked in the form of filaments or granules. During the melt extrusion process, the melt containing a foaming agent is pre-foamed to obtain a pre-foamed polymer part. The lattice units in the polymer part contain pores and gaps. By immersing the polymer part in a solvent, defects in the lattice structure of the polymer part are eliminated while maintaining structural and dimensional stability. This reduces the probability of surface bubbles forming during the foaming process after supercritical fluid impregnation, thereby reducing the apparent density and compression set of the polymer foam product while improving its resilience and tensile properties. Specifically, lubricants and nucleating agents can improve the resilience and tensile strength of the polymer foam product, as well as reduce its apparent density.

[0045] 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.

[0046] Specifically, the weight of the foaming agent can be one of, or any two of, 1 part, 1.5 parts, 2 parts, 2.5 parts, 3 parts, 4 parts, or 5 parts.

[0047] 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.

[0048] 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.

[0049] 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.

[0050] 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.

[0051] 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.

[0052] Specifically, the Shore hardness of the thermoplastic elastomer can be one or any two of 85 A, 86 A, 87 A, 88 A, 89 A, 90 A, 91 A, 92 A, 93 A, 94 A, and 95 A; preferably 88 A-90 A.

[0053] In this application, the Shore hardness of thermoplastic elastomers affects the performance of polymer foam products. Specifically, if the Shore hardness of thermoplastic elastomers is too low, it will lead to a decrease in the uniformity of the appearance and resilience of polymer foam products, as well as an increase in the permanent compression set. If the Shore hardness of thermoplastic elastomers is too high, it will lead to excessively high temperatures during high-pressure fluid impregnation foaming, resulting in degradation, yellowing, and inducing overall performance degradation.

[0054] Specifically, the thickness of the polymer lattice is 0.5-5 mm; for example, it can be one or any two of 0.5 mm, 0.7 mm, 1 mm, 1.5 mm, 2 mm, 2.5 mm, 3 mm, 3.5 mm, 4 mm, 4.5 mm, and 5 mm, preferably 1-3 mm.

[0055] In this application, the thickness of the lattice of the polymer component is within the above-mentioned range, which is beneficial for the polymer component to expand uniformly during the foaming process, thereby improving the resilience and tensile strength of the polymer foam product, while reducing the compression permanent deformation of the polymer foam product.

[0056] In this application, a lattice refers to a single structure with a specific topology, which can be at least one of a cube, sphere, honeycomb, and octahedron. The thickness of the lattice refers to the height of a single structure with a specific topology. The thickness of the lattice of the polymer part can be obtained by setting it during the 3D printing process.

[0057] 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℃.

[0058] 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, and 30 min.

[0059] In this application, the temperature and time of solvent immersion affect the performance of polymer foam products. Specifically, if the solvent immersion temperature is too low, the solvent penetration will be poor, resulting in poor treatment of burrs on the surface of the product and uneven materials on the inside. If the solvent immersion temperature is too high, the interface will collapse, causing a decrease in mechanical properties.

[0060] Specifically, the volume ratio of the alcohol to acetone is (45:55) to (25:75); for example, it can be one of 45:55, 40:60, 35:65, 30:70, 25:75 or any two of them; preferably (40:60) to (30:70).

[0061] In this application, excessive acetone content can lead to excessive swelling of the sample surface, resulting in decreased interfacial adhesion and surface collapse. Excessive alcohol content can lead to poor solvent surface treatment effect and excessive residual burrs on the product surface, affecting subsequent foaming. A volume ratio of alcohol to acetone of (60:40) to (50:50) is beneficial for adjusting the dissolution rate and controlling the surface treatment rate and solvent evaporation rate.

[0062] In some embodiments, the antioxidant is a hindered amine stabilizer, such as N,N-di-sec-butyl-p-phenylenediamine, tris(2,4-di-tert-butylphenyl) phosphite, pentaerythritol tetrakis[β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate], etc.

[0063] In this application, hindered amine antioxidants can not only improve the antioxidant properties of polymer foam products, but also further reduce the apparent density of polymer foam products.

[0064] In some embodiments, the alcohol includes at least one of a monohydric alcohol and / or a polyhydric alcohol.

[0065] Specific examples of monohydric alcohols include at least one of ethanol, propanol, butanol, and pentanol.

[0066] 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.

[0067] Preferably, the alcohol is a monohydric alcohol; in this application, when the alcohol is a monohydric alcohol, it is beneficial to improve the resilience and tensile strength of the polymer foam product.

[0068] In some embodiments, the melt mass flow rate of the thermoplastic elastomer resin at 210°C and 2.16 kg is 0.2-12 g / 10 min, for example, it can be one or 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, 12 g / 10 min; preferably 6-10 g / 10 min.

[0069] In this application, the melt flow rate of the thermoplastic elastomer resin at 210°C and 2.16 kg is 0.2-12 g / 10 min, which can prevent the polymer parts from undergoing lattice collapse and deformation during foaming, thereby improving the resilience and tensile strength of the polymer foam products.

[0070] In some embodiments, the temperature of the melt extrusion is 100-200°C, preferably 150-190°C.

[0071] In some embodiments, the 3D printing temperature is 210-290°C, at which temperature the thermoplastic resin composite material can be melted to obtain a polymer part.

[0072] In some embodiments, the supercritical fluid impregnation temperature is 10-180°C, for example, it can be a range of one or any two of 10°C, 30°C, 50°C, 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 0.3-12 h; for example, it can be a range of one or any two of 0.3 h, 0.5 h, 1 h, 2 h, 4 h, 6 h, 8 h, 10 h, and 12 h.

[0073] In some embodiments, the supercritical fluid includes at least one of CO2 fluid and N2 fluid.

[0074] In some embodiments, the solubility of the supercritical fluid in the polymer foam product 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%.

[0075] In this application, the solubility of supercritical fluid in polymer foam products can be controlled by adjusting the pressure and temperature of supercritical fluid impregnation. The solubility (%) of supercritical fluid in polymer foam products is (m2-m1)×100% / m1, where m1 is the mass of the polymer part and m2 is the mass of the polymer foam product.

[0076] During supercritical foaming, the plasticizing effect of the supercritical fluid lowers the softening point of the polymer. Prolonged supercritical fluid impregnation can cause the polymer part to creep under its own gravity. By controlling the solubility of the supercritical fluid, the temperature and time of supercritical fluid impregnation, it is possible to prevent creep in the polymer part during supercritical fluid impregnation and foaming, thus obtaining polymer foam products with low compression set, high tensile strength, and high resilience.

[0077] 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.

[0078] 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.

[0079] In some implementations, at least one of the following conditions is met:

[0080] (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);

[0081] Specifically, thermoplastic polyester elastomers refer to linear block copolymers containing polybutylene terephthalate (PBT) polyester hard segments and aliphatic polyester or polyether soft segments.

[0082] Specifically, examples of polyamides include PA6, PA12, PA66, PA610, PA612, PA6I, PA6T, and PEBA (polyether amide block copolymer).

[0083] (b) The foaming agent comprises at least one of CO2 fluid, N2 fluid, flammable alkane, azodicarbonamide, carbonate, and N,N-dinitrospentamethylenetetramine;

[0084] (c) The nucleating agent includes at least one of calcium carbonate, talc, mica, montmorillonite, nano silica, carbon black, and carbon nanotubes;

[0085] (d) The color masterbatch includes organic dyes;

[0086] (e) The matte agent comprises at least one of sorbitol monopalmitate and xylitol ester;

[0087] (f) The lubricant includes at least one of polyethylene wax, stearic acid, lead stearate, zinc stearate, and paraffin.

[0088] The production method of the thermoplastic resin mixture in this application is not particularly strict and can be carried out using blending equipment such as a mixer. The order of addition of components is not particularly strict and can be either simultaneous or in a specific 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 predetermined proportion for mixing. The resin used in the masterbatch can be the thermoplastic elastomer described in this application.

[0089] 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.

[0090] In a second aspect, this application provides a polymer foam product prepared by a method for preparing the polymer foam product.

[0091] In some embodiments, the apparent density of the polymer foam product is 100-300 kg / m³. 3 Rebound rate ≥60%, compression set ≤50%.

[0092] Specifically, the apparent density of polymer foam products can be 100 kg / m³. 3 130kg / m 3 150kg / m 3 180kg / m 3 200kg / m 3 220kg / m 3 250kg / m 3 270kg / m 3 300kg / m 3 The range of values ​​between one or any two of them;

[0093] Specifically, the resilience of polymer foam products can be a range of one or any two of the following: 60%, 62%, 65%, 67%, 70%, 73%, 75%, 77%, and 80%.

[0094] Specifically, the compression set of the polymer foam product can be a range of one or any two of the following: 5%, 7%, 9%, 11%, 13%, 15%, 20%, 23%, 25%, 27%, 30%, 35%, 40%, 45%, and 50%.

[0095] Specifically, the apparent density of the polymer foam product is measured using a densitometer.

[0096] Specifically, the average diameter of the cells in the polymer foam product was obtained by scanning electron microscopy.

[0097] Specifically, the expansion ratio (%) of the polymer foam product is (S1-S2) / S2×100%; where S1 is the length, width or height of the polymer foam product, and S2 is the length, width or height of the polymer component; taking the length direction as an example, S1 is the length of the polymer foam product, and S2 is the length of the polymer component.

[0098] Specifically, the resilience of polymer foam products is obtained by testing with a resilience meter.

[0099] Specifically, the compression set of polymer foam products is obtained by testing with a compression set tester.

[0100] In a third aspect, this application provides a shoe material comprising the aforementioned polymer foam product.

[0101] The raw materials used in the embodiments and comparative examples are described below, but are not limited to these materials:

[0102] Thermoplastic elastomer A: Polyether-type TPU, Shore hardness 85A, WHT-8185, Wanhua Chemical;

[0103] Thermoplastic elastomer B: Polyether-type TPU, Shore hardness 88A, WHT-8885, Wanhua Chemical;

[0104] Thermoplastic elastomer C: Polyether-type TPU, Shore hardness 90A, WHT-8190, Wanhua Chemical;

[0105] Thermoplastic elastomer D: Polyether-type TPU, Shore hardness 95A, WHT-8195, Wanhua Chemical;

[0106] Thermoplastic elastomer E: Polyester-type TPU, Shore hardness 85A, 385SX, Covestro;

[0107] Thermoplastic elastomer F: TPEE, Shore hardness 45D, Hytrel 4556, Celanese, USA;

[0108] Thermoplastic elastomer G: EVA, Shore hardness 85A, 1985A, Celanese, USA;

[0109] Thermoplastic elastomer H: Polyether-type TPU, Shore hardness 80A, WHT-8180, Wanhua Chemical;

[0110] Thermoplastic elastomer I: Polyether-type TPU, Shore hardness 64D, WHT-8264, Wanhua Chemical;

[0111] Foaming agent: Sodium bicarbonate, commercially available;

[0112] Color masterbatch: Polybatc, Clariant, commercially available;

[0113] Matte finish: Xylitol ester, commercially available

[0114] Lubricant: Polyethylene wax, commercially available;

[0115] Antioxidant A: N,N-di-sec-butyl-p-phenylenediamine;

[0116] Antioxidant B: Tris(2,4-di-tert-butylphenyl) phosphite, commercially available;

[0117] Antioxidant C: Pentaerythritol tetrakis[β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionic acid], commercially available.

[0118] Example 1

[0119] This embodiment provides a method for preparing a polymer foam product, including the following steps:

[0120] S1: Add 82 parts by weight of thermoplastic elastomer A, 4 parts by weight of foaming agent, 6 parts by weight of color masterbatch, 4 parts by weight of matting agent, 3 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 a thermoplastic resin mixture.

[0121] Thermoplastic resin mixture is added to a single-screw extruder for melt extrusion to obtain wire; the melt extrusion temperature is 200℃.

[0122] The obtained filament melt was 3D printed according to the planned path to obtain a polymer part; the thickness of the polymer part's lattice was 2.5 mm, and the 3D printing parameters were as follows: printing temperature was 210℃;

[0123] S2: The polymer part obtained in step S1 is placed in a solvent and immersed at 30°C for 15 minutes. Then, after washing and drying, a pretreated polymer part is obtained. The solvent is a mixture of ethanol and acetone, with a volume ratio of ethanol to acetone of 40:60.

[0124] S3: The pretreated polymer parts are placed in an autoclave and impregnated with nitrogen fluid. The impregnated polymer parts are depressurized and foamed within 1 second to obtain a polymer foam product. The impregnation temperature is 130℃, the pressure is 20MPa, the time is 3h, and the solubility of nitrogen fluid in the polymer foam product is 1%.

[0125] Example 2

[0126] This embodiment provides a method for preparing a polymer foam product. The difference between the other embodiments is that thermoplastic elastomer B is used instead of thermoplastic elastomer A.

[0127] Example 3

[0128] This embodiment provides a method for preparing a polymer foam product. The difference between the other embodiments is that thermoplastic elastomer C is used instead of thermoplastic elastomer A.

[0129] Example 4

[0130] This embodiment provides a method for preparing a polymer foam product. The difference between the other embodiments is that thermoplastic elastomer D is used instead of thermoplastic elastomer A.

[0131] Example 5

[0132] This embodiment provides a method for preparing a polymer foam product. The difference between the other embodiments is that thermoplastic elastomer E is used instead of thermoplastic elastomer A.

[0133] Example 6

[0134] This embodiment provides a method for preparing a polymer foam product. The difference between the other embodiments is that thermoplastic elastomer F is used instead of thermoplastic elastomer A.

[0135] Example 7

[0136] This embodiment provides a method for preparing a polymer foam product. The difference between the other embodiments is that thermoplastic elastomer G is used instead of thermoplastic elastomer A.

[0137] Example 8

[0138] This embodiment provides a method for preparing a polymer foam product. The difference between this embodiment and the other embodiment 1 is that the thickness of the polymer lattice is 3 mm.

[0139] Example 9

[0140] This embodiment provides a method for preparing a polymer foam product. The difference between the other embodiments is that the thickness of the polymer lattice is 1 mm.

[0141] Example 10

[0142] This embodiment provides a method for preparing a polymer foam product. The difference between this embodiment and the other embodiment 1 is that the thickness of the polymer lattice is 0.5 mm.

[0143] Example 11

[0144] This embodiment provides a method for preparing a polymer foam product. The difference between this embodiment and the other embodiment 1 is that the thickness of the polymer lattice is 5 mm.

[0145] Example 12

[0146] This embodiment provides a method for preparing a polymer foam product. The difference between the other embodiments is that antioxidant B is used instead of antioxidant A.

[0147] Example 13

[0148] This embodiment provides a method for preparing a polymer foam product. The difference between the other embodiments is that antioxidant C is used instead of antioxidant A.

[0149] Example 14

[0150] This embodiment provides a method for preparing a polymer foam product, which differs from Example 1 in that the mass ratio of ethanol to acetone is 30:70.

[0151] Example 15

[0152] This embodiment provides a method for preparing a polymer foam product, which differs from Example 1 in that the mass ratio of ethanol to acetone is 25:75.

[0153] Example 16

[0154] This embodiment provides a method for preparing a polymer foam product, which differs from Example 1 in that the mass ratio of ethanol to acetone is 45:55.

[0155] Example 17

[0156] This embodiment provides a method for preparing a polymer foam product, including the following steps:

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

[0158] The thermoplastic resin mixture is added to a single-screw extruder for melt extrusion to obtain wire melt; the melt extrusion temperature is 200℃.

[0159] The obtained filament melt was 3D printed according to the planned path to obtain a polymer part; the thickness of the polymer part's lattice was 2.5 mm, and the 3D printing parameters were as follows: printing temperature was 220℃;

[0160] S2: The polymer part obtained in step S1 is placed in a solvent and soaked at 10°C for 30 minutes. Then, after washing and drying, a pretreated polymer part is obtained. The solvent is a mixture of ethanol and acetone, with a volume ratio of ethanol to acetone of 60:40.

[0161] S3: The pretreated polymer parts are placed in an autoclave and impregnated with nitrogen fluid. The impregnated polymer parts are depressurized and foamed within 1 second to obtain a polymer foam product. The impregnation temperature is 120℃, the pressure is 30MPa, the time is 0.5h, and the solubility of nitrogen fluid in the polymer foam product is 3%.

[0162] Example 18

[0163] This embodiment provides a method for preparing a polymer foam product, including the following steps:

[0164] S1: Add 90 parts by weight of thermoplastic elastomer A, 1 part by weight of foaming agent, 10 parts by weight of color masterbatch, 0.1 parts by weight of matting agent, 0.1 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 a thermoplastic resin mixture.

[0165] The thermoplastic resin mixture is added to a single-screw extruder for melt extrusion to obtain wire melt; the melt extrusion temperature is 200℃.

[0166] The obtained filament melt was 3D printed according to the planned path to obtain a polymer part; the 3D printing parameters are as follows: the thickness of the polymer part's lattice is 2.5 mm, and the printing temperature is 210℃.

[0167] S2: The polymer part obtained in step S1 is placed in a solvent and immersed at 50°C for 5 minutes. Then, after washing and drying, a pretreated polymer part is obtained. The solvent is a mixture of ethanol and acetone, with a volume ratio of ethanol to acetone of 60:40.

[0168] S3: The pretreated polymer parts are placed in an autoclave and impregnated with nitrogen fluid. The impregnated polymer parts are depressurized and foamed within 1 second to obtain a polymer foam product. The impregnation temperature is 40℃, the pressure is 10MPa, the time is 6h, and the solubility of nitrogen fluid in the polymer foam product is 0.5%.

[0169] Example 19

[0170] This embodiment provides a method for preparing a polymer foam product, which differs from Embodiment 1 in that: the thermoplastic resin mixture 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 mixture does not contain a foaming agent.

[0171] Comparative Example 1

[0172] This comparative example provides a method for preparing a polymer foam product, which differs from Example 1 in that it does not include step S2.

[0173] Comparative Example 2

[0174] This comparative example provides a method for preparing a polymer foam product, which differs from Example 1 in that: in step S1, thermoplastic elastomer H is used instead of thermoplastic elastomer A.

[0175] Comparative Example 3

[0176] This comparative example provides a method for preparing a polymer foam product, which differs from Example 1 in that: in step S1, thermoplastic elastomer I is used instead of thermoplastic elastomer A.

[0177] Comparative Example 4

[0178] This comparative example provides a method for preparing a polymer foam product, which differs from Example 1 in that: in step S1, the thickness of the polymer lattice is 0.1 mm.

[0179] Comparative Example 5

[0180] This comparative example provides a method for preparing a polymer foam product, which differs from Example 1 in that: in step S1, the thickness of the polymer lattice is 6 mm.

[0181] Comparative Example 6

[0182] This comparative example provides a method for preparing a polymer foam product, which differs from Example 1 in that the mass ratio of ethanol to acetone is 55:45.

[0183] Comparative Example 7

[0184] This comparative example provides a method for preparing a polymer foam product, which differs from Example 1 in that the mass ratio of ethanol to acetone is 15:85.

[0185] Comparative Example 8

[0186] This comparative example provides a method for preparing a polymer foam product, which differs from Example 1 in that the soaking temperature is 5°C.

[0187] Comparative Example 9

[0188] This comparative example provides a method for preparing a polymer foam product, which differs from Example 1 in that the soaking temperature is 60°C.

[0189] Comparative Example 10

[0190] This comparative example provides a method for preparing a polymer foam product, which differs from Example 1 in that no antioxidant is added.

[0191] Performance testing

[0192] The polymer parts and polymer foam products obtained in the examples and comparative examples were subjected to performance tests, and the test methods are as follows:

[0193] (1) Apparent density: obtained by automatic water density meter;

[0194] (2) Rebound rate: According to GB / T 6670-2008 standard, it is measured by a falling ball rebound meter;

[0195] (3) Tensile strength: The tensile strength was measured by using a universal testing machine at a speed of 300 mm / min until the fracture. The fracture strength was taken as the tensile strength.

[0196] (4) Compression permanent deformation: The sample was compressed to 50% strain using a compression permanent deformation tester, placed in a 50℃ oven for 3 hours, and then placed at room temperature for 1 hour before the sample recovered its thickness. The recovered thickness divided by the initial thickness was taken as the compression permanent deformation.

[0197] (5) Appearance: Visual inspection.

[0198] The test results are shown in Table 1.

[0199] Table 1

[0200]

[0201]

[0202] As shown in Table 1, the apparent density of the polymer foam product of this application is 100-300 kg / m³. 3 Resilience ≥60%, tensile strength ≥10MPa, compression set ≤35%.

[0203] The experimental data from Examples 1-4 and Comparative Examples 2-3 show that when the Shore hardness of the thermoplastic elastomer is 88-90A, the resilience of the obtained polymer foam product is ≥67%, the tensile strength is ≥16MPa, and the compression set is ≤22.5%. This indicates that when the Shore hardness of the thermoplastic elastomer is 88-90A, the polymer foam product has higher resilience and tensile strength, and lower compression set.

[0204] The experimental data from Examples 1 and 8-11 show that when the thickness of the polymer lattice is 1-3 mm, the resilience of the obtained polymer foam product is ≥63%, the tensile strength is ≥14 MPa, and the compression set is ≤27%. This indicates that when the thickness of the polymer lattice is 1-3 mm, the resilience and tensile strength of the polymer foam product can be further improved, and the compression set of the polymer foam product can be reduced.

[0205] The experimental data from Examples 1 and 12-13 show that when the antioxidant is a hindered amine antioxidant, the tensile strength of the obtained polymer foam product is ≥15MPa and the compression set is ≤25%, indicating that when the antioxidant is a hindered amine antioxidant, the polymer foam product has higher tensile strength and lower compression set.

[0206] The experimental data from Examples 1, 14-16 and Comparative Examples 6-7 show that when the volume ratio of alcohol to acetone is (40:60) to (30:70), the resulting polymer foam product has a resilience of ≥62%, a tensile strength of ≥14MPa, and a compression set of ≤28%. This indicates that when the volume ratio of alcohol to acetone is (40:60) to (30:70), the polymer foam product has higher tensile strength and resilience, as well as lower compression set.

[0207] 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 a polymer foam product, 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 polymer part; wherein the thickness of the polymer part lattice is 0.5-5mm; S2: The polymer part is immersed in a solvent, then washed and dried to obtain a pretreated polymer part; 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 (45:55)-(25:75). S3: After impregnating the pretreated polymer parts with supercritical fluid, foaming is performed to obtain polymer foam products; The thermoplastic resin mixture comprises the following raw materials in parts by weight: 75-90 parts thermoplastic elastomer resin, 1-5 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 thermoplastic elastomer resin has a Shore hardness of 85A-95A.

2. The method for preparing the polymer foam product as described in claim 1, characterized in that, The thickness of the polymer component lattice is 1-3 mm.

3. The method for preparing the polymer foam product as described in claim 1, characterized in that, The volume ratio of the alcohol to acetone is (40:60) - (30:70).

4. The method for preparing the polymer foam product as described in claim 1, characterized in that, The antioxidant is a hindered amine antioxidant.

5. The method for preparing the polymer foam product 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 the polymer foam product 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 the polymer foam product as described in claim 1, characterized in that, The supercritical fluid impregnation temperature is 10-180℃, the pressure is 10-30MPa, and the time is 0.3-12h.

8. The method for preparing the polymer foam product as described in claim 1, characterized in that, The supercritical fluid includes at least one of CO2 fluid and N2 fluid.

9. The method for preparing the polymer foam product as described in claim 1, characterized in that, The solubility of the supercritical fluid in the polymer foam product is 0.5-8%; the solubility (%) of the supercritical fluid in the polymer foam product is (m2-m1)×100% / m1; where m1 is the mass of the polymer part and m2 is the mass of the polymer foam product.

10. The method for preparing the polymer foam product according to 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.

11. A polymer foam product, prepared by the method for preparing the polymer foam product according to any one of claims 1-10.

12. The polymer foam product as described in claim 11, characterized in that, The apparent density of the polymer foam product is 100-300 kg / m³. 3 Rebound rate ≥60%, compression set ≤50%.

13. A shoe material, characterized in that, Including the polymer foam products as described in claim 11 or 12.

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