Polymer foam product, preparation method thereof and shoe material

Abstract

The invention provides a polymer foam product, a preparation method thereof and a shoe material, and belongs to the technical field of 3D printing. The preparation method comprises the following steps: firstly, carrying out melt extrusion on a thermoplastic resin mixed material, and carrying out 3D printing on the obtained thermoplastic resin composite material according to a planned path to obtain a polymer workpiece; the preparation method comprises the following steps: firstly, soaking a polymer workpiece in a solvent, and finally, soaking the soaked polymer workpiece in supercritical fluid, and foaming to obtain a polymer foam product. By adopting the method provided by the invention to prepare the polymer foam product, the polymer foam product with low apparent density, low compression permanent deformation, high rebound resilience and high tensile strength can be obtained.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of 3D printing, in particular to a polymer foam product, 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 adhesive 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 shoe 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 shoe 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 generated or residual substances, which has been used for the preparation of shoe materials. Combining customized 3D printing technology and lightweight foaming technology is expected to realize the preparation of ultra-light shoe soles. However, foaming after forming a polymer part 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 part, resulting in a decrease in the size accuracy of the printed part. 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 solution 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: 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 0.5-5 mm; S2: soaking the polymer part in a solvent, then washing and drying to obtain a pretreated polymer part; 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); S3: foaming the pre-processed polymer piece after supercritical fluid impregnation to obtain a polymer foam product; The thermoplastic resin mixture comprises the following raw materials by weight: 75-90 parts of thermoplastic elastomer resin, 0-5 parts of foaming agent, 1-10 parts of color masterbatch, 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. The Shore hardness of the thermoplastic elastomer resin is 85A-95A.

[0006] In some embodiments, the thickness of the polymer piece lattice is 1-3 mm.

[0007] In some embodiments, the alcohol includes at least one of monohydric alcohol and polyhydric alcohol.

[0008] In some embodiments, the antioxidant is a hindered amine antioxidant.

[0009] In some embodiments, in step S2, the temperature of the soaking is 20-40℃, and the time is 1-30 min.

[0010] In some embodiments, the volume ratio of the alcohol and acetone is (40:60)-(30:70).

[0011] In some embodiments, the temperature of the supercritical fluid impregnation is 10-180℃, the pressure is 10-30 MPa, and the time is 0.3-12 h. In some embodiments, the supercritical fluid includes at least one of CO2 fluid and N2 fluid. In some embodiments, the solubility of the supercritical fluid in the polymer foam product is 0.5-8%.

[0012] In some embodiments, at least one of the following conditions is met: (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; (b) the foaming agent includes at least one of CO2 fluid, N2 fluid, flammable alkane, azodicarbonamide, carbonate, N, N-dinitrosopentamethylenetetramine; (c) the nucleating agent includes at least one of calcium carbonate, talc, mica, montmorillonite, nanosilica, carbon black, and carbon nanotube; (d) the color masterbatch includes organic dye; (e) the matte agent includes at least one of sorbitol monopalmitate and xylitol ester. (f) the lubricant comprises at least one of polyethylene wax, stearic acid, lead stearate, zinc stearate, paraffin wax.

[0013] In a second aspect, there is provided a polymer foam product prepared by the method for preparing a polymer foam product.

[0014] In some embodiments, the polymer foam product has an apparent density of 100-300 kg / m 3 , a resilience of ≥ 60%, and a compression set of ≤ 50%.

[0015] In a third aspect, there is provided a shoe material comprising the polymer foam product.

[0016] Compared with the prior art, the beneficial effects of the present disclosure are: in the process of 3D printing of the present application, the thermoplastic resin composite is in the form of a filament or a particle and is subjected to melt extrusion stacking, and in the process of melt extrusion, the melt containing the foaming agent is subjected to pre-foaming to obtain a pre-foamed polymer part; there are holes and gaps in the lattice units in the polymer part, and by immersing the polymer part in a solvent, the defects in the lattice structure of the polymer part are eliminated while the structure and size of the polymer part are kept stable, the probability of forming surface bubbles in the polymer part after being impregnated with a supercritical fluid is reduced, and the resilience and tensile properties of the polymer foam product are improved while the apparent density and compression set of the polymer foam product are reduced. DETAILED DESCRIPTION

[0017] In order to facilitate the understanding of the present disclosure, the present disclosure will be described more fully below. However, the present disclosure can be implemented in many different forms and is not limited to the embodiments described herein. On the contrary, the purpose of providing these embodiments is to make the disclosure of the present disclosure more thorough and comprehensive.

[0018] As used herein, the term: "prepared from" is synonymous with "comprising". The terms "comprising", "including", "having" "with" or any other similar phrase as used herein, are intended to encompass non-exclusive inclusion. For example, a composition, step, method, article, or apparatus that comprises a list of elements is not necessarily limited to only those elements but can include other elements not expressly listed or inherent to such composition, step, method, article, or apparatus.

[0019] The conjunctive term "comprising", used in the context of describing the chemical components of the compositions of the present application, does not necessarily exclude other components. For example, a jointing including compositions of the present application, can not only be composed of the recited components but also of other components. The term "consisting essentially of to avoid any unrecited elements, steps or components. If used in the claims, this phrase shall have the meaning set forth in the jurisdiction where the claim is filed. When the phrase "consisting essentially of appears in the body of the claims, it defines the scope of the invention with the exclusion of only those elements that are added unrelated to the basic or novel characteristics of the invention. When the phrase "consisting essentially of appears in the introductory clause of a claim, it defines the scope of the invention with the exclusion of unrecited elements, steps or components unless otherwise dictated by the context of the claim.

[0020] When equivalent, concentration, or other value or parameter is expressed in a range, a preferred range, or a series of upper preferred values and lower preferred values, it is to be understood that all ranges formed by any pair of any upper range limit or preferred value and any lower range limit or preferred value, even if the range is not expressly stated, are to be specifically disclosed. For example, where a range "1-5" is disclosed, the disclosure is to be interpreted to include ranges of "1-4", "1-3", "1-2", "1-2 and 4-5", "1-3 and 5", etc. When numerical ranges are disclosed, unless otherwise stated, the range is intended to include both the endpoints and all integers and fractions within that range.

[0021] In these embodiments, the parts and percentages described are by mass, unless otherwise indicated.

[0022] "Mass parts" refers to a basic unit of measurement that represents the proportional relationship of the mass of multiple components, 1 part can represent any unit mass, such as 1 g, 2.689 g, etc. If we say that the mass of component A is a parts and the mass of component B is b parts, it means that the mass ratio of component A to component B is a:b. It should not be misunderstood that unlike the mass percentage, the sum of the mass parts of all components is not limited to 100 parts.

[0023] "and / or" is used to indicate one or both of the stated circumstances can occur, for example, A and / or B includes (A and B) and (A or B).

[0024] In a first aspect of the present application, a method for preparing a polymer foam product is provided, comprising the following steps: S1: melt-extruding a thermoplastic resin mixture into a single-screw extruder to obtain a thermoplastic resin composite; and 3D printing the thermoplastic resin composite to obtain a polymer part; wherein the thickness of the crystal lattice of the polymer part is 0.5-5 mm; S2: soaking the polymer part in a solvent, and then washing and drying to obtain a pretreated polymer part; wherein the solvent is a mixture of alcohol and acetone, the soaking temperature is 10-50°C; and the volume ratio of the alcohol to the acetone is (45:55)-(25:75); S3: after the pretreated polymer product is immersed in the supercritical fluid, foaming is performed to obtain a polymer foam product; The thermoplastic resin mixture comprises the following raw materials in parts by weight: 75-90 parts of thermoplastic elastomer resin, 0-5 parts of foaming agent, 1-10 parts of color masterbatch, 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. The Shore hardness of the thermoplastic elastomer resin is 85A-95A.

[0025] In the process of 3D printing of the present application, the thermoplastic resin composite is melt-extruded and stacked in the form of a filament or a particle. In the process of melt-extrusion, the melt containing the foaming agent is pre-foamed to obtain a pre-foamed polymer product. There are holes and gaps in the crystal lattice unit of the polymer product. By immersing the polymer product in a solvent, the defects in the crystal lattice structure of the polymer product are eliminated while the structure and size of the polymer product are kept stable. The probability of forming surface bubbles in the polymer product after immersion in the supercritical fluid is reduced. The apparent density and compression permanent deformation of the polymer foam product are reduced, and the rebound performance and tensile performance of the polymer foam product are improved. Specifically, the lubricant and the nucleating agent can improve the rebound performance and tensile strength of the polymer foam product, and reduce the apparent density.

[0026] Specifically, the weight parts of the thermoplastic elastomer can be one or a range value between any two of 75 parts, 77 parts, 80 parts, 83 parts, 85 parts, 88 parts, and 90 parts.

[0027] Specifically, the weight parts of the foaming agent can be one or a range value between any two of 1 part, 1.5 parts, 2 parts, 2.5 parts, 3 parts, 4 parts, and 5 parts.

[0028] Specifically, the weight parts of the color masterbatch can be one or a range value between any two of 1 part, 2 parts, 3 parts, 4 parts, 5 parts, 6 parts, 7 parts, 8 parts, 9 parts, and 10 parts.

[0029] Specifically, the weight parts of the matte agent can be one or a range value between any two of 0.1 part, 0.5 part, 1 part, 1.5 part, 2 part, 2.5 part, 3 part, 4 part, 5 part, 6 part, 7 part, 7.5 part, 8 part, 8.5 part, 9 part, 9.5 part, and 10 part.

[0030] Specifically, the weight parts of the lubricant can be one or a range value between any two of 0.1 part, 0.5 part, 1 part, 1.5 part, 2 part, 2.5 part, 3 part, 3.5 part, 4 part, 4.5 part, and 5 part.

[0031] Specifically, the weight parts of the nucleating agent can be in a range between one or any two of 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, 1 part.

[0032] Specifically, the weight parts of the antioxidant can be in a range between one or any two of 0.1 parts, 0.2 parts, 0.3 parts, 0.4 parts, 0.5 parts.

[0033] Specifically, the Shore hardness of the thermoplastic elastomer can be in a range between 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, 95 A; preferably 88 A-90 A.

[0034] In the present application, the Shore hardness of the thermoplastic elastomer affects the performance of the polymer foam product. Specifically, if the Shore hardness of the thermoplastic elastomer is too low, it will cause the appearance uniformity and resilience of the polymer foam product to decrease, and cause the permanent compression set of the resilience to increase; if the Shore hardness of the thermoplastic elastomer is too high, it will cause the temperature to be too high during high-pressure fluid impregnation foaming, resulting in degradation, yellowing and inducing overall performance decay.

[0035] Specifically, the thickness of the crystal lattice of the polymer piece is 0.5-5mm; for example, it can be in a range between one or any two of 0.5mm, 0.7mm, 1mm, 1.5mm, 2mm, 2.5mm, 3mm, 3.5mm, 4mm, 4.5mm, 5mm, preferably 1-3mm.

[0036] In the present application, the thickness of the crystal lattice of the polymer piece within the above range is beneficial to the uniform expansion of the polymer piece during foaming, thereby improving the resilience and tensile strength of the polymer foam product, and reducing the permanent compression set of the polymer foam product.

[0037] In the present application, the crystal lattice refers to a single structure with a specific topological structure, which can be at least one of a cube, a sphere, a honeycomb, and an octahedron, and the thickness of the crystal lattice refers to the height of a single structure with a specific topological structure. The thickness of the crystal lattice of the polymer piece can be obtained by setting during 3D printing.

[0038] Specifically, the temperature of the soaking is 10-50℃, for example, it can be in a range between one or any two of 10℃, 12℃, 15℃, 17℃, 20℃, 23℃, 25℃, 28℃, 30℃, 32℃, 35℃, 37℃, 40℃, 43℃, 45℃, 48℃, 50℃, preferably 20-40℃.

[0039] Specifically, the soaking time is 1-30 min, for example, it can be one of 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 or a range value between any two of them.

[0040] In the present application, the temperature and time of solvent soaking affect the performance of the polymer foam product. Specifically, if the temperature of solvent soaking is too low, the solvent penetration ability is poor, and the treatment effect on the product surface burrs and internal uneven substances is not good. If the temperature of solvent soaking is too high, the interface collapses, causing the mechanical properties to decrease.

[0041] Specifically, the volume ratio of the alcohol and acetone is (45:55)-(25:75); for example, it can be one of 45:55, 40:60, 35:65, 30:70, 25:75 or a range value between any two of them; preferably (40:60)-(30:70).

[0042] In the present application, if the content of acetone is too high, the sample surface will swell excessively, causing the interface adhesion to decrease and the surface to collapse. If the content of alcohol is too high, the solvent will have a poor treatment effect on the surface, and there will be too many burrs on the product surface affecting subsequent foaming. When the volume ratio of alcohol and acetone is (60:40)-(50:50), it is beneficial to adjust the dissolution speed, control the surface treatment speed and the solvent evaporation speed.

[0043] In some embodiments, the antioxidant is a hindered amine stabilizer, for example, it can be N,N-di-sec-butyl-p-phenylenediamine, tris(2,4-di-tert-butylphenyl) phosphite, tetra[β-(3,5-di-tert-butyl-4-hydroxyphenyl) propionic acid] pentaerythritol ester, etc.

[0044] In the present application, the hindered amine antioxidant not only improves the antioxidant performance of the polymer foam product, but also further reduces the apparent density of the polymer foam product.

[0045] In some embodiments, the alcohol includes at least one of monohydric alcohol and / or polyhydric alcohol.

[0046] As specific examples of monohydric alcohol, at least one of ethanol, propanol, butanol, and pentanol can be listed.

[0047] Polyhydric alcohol includes at least one of dihydric alcohol and trihydric alcohol; as specific examples of dihydric alcohol, at least one of ethylene glycol, 1,2-propanediol, 1,4-butanediol, 1,6-hexanediol, neopentyl glycol, and diethylene glycol can be listed; as specific examples of trihydric alcohol, at least one of glycerol and trimethylolpropane can be listed.

[0048] Preferably, the alcohol is a monohydric alcohol; in the present application, the alcohol is a monohydric alcohol, which is beneficial to improve the resilience and tensile strength of the polymer foam product.

[0049] In some embodiments, the thermoplastic elastomer resin has a melt mass-flow rate of 0.2-12 g / 10 min at 210℃, 2.16 kg, for example, it can be one of or a range value between any two of 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.

[0050] In the present application, the thermoplastic elastomer resin has a melt mass-flow rate of 0.2-12 g / 10 min at 210℃, 2.16 kg, which can avoid the lattice collapse deformation of the polymer product during the foaming process, thereby improving the resilience and tensile strength of the polymer foam product.

[0051] In some embodiments, the temperature of the melt extrusion is 100-200℃, preferably 150-190℃.

[0052] In some embodiments, the temperature of the 3D printing is 210-290℃, at which the thermoplastic resin composite can be melted to obtain the polymer product.

[0053] In some embodiments, the temperature of the supercritical fluid impregnation is 10-180℃, for example, it can be one of or a range value between any two of 10℃, 30℃, 50℃, 80℃, 90℃, 100℃, 110℃, 120℃, 130℃, 140℃, 150℃, 160℃, 170℃, 180℃; preferably 100-150℃; the pressure is 10-30 MPa; for example, it can be one of or a range value between any two of 10 MPa, 12 MPa, 15 MPa, 18 MPa, 20 MPa, 23 MPa, 25 MPa, 28 MPa, 30 MPa, preferably 15-25 MPa; the time is 0.3-12 h; for example, it can be one of or a range value between any two of 0.3 h, 0.5 h, 1 h, 2 h, 4 h, 6 h, 8 h, 10 h, 12 h.

[0054] In some embodiments, the supercritical fluid comprises at least one of CO2 fluid, N2 fluid.

[0055] In some embodiments, the supercritical fluid has a solubility in the polymer foam product of 0.5-8%; for example, it can be one 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% or a range between any two of them; preferably, it is 0.8-5%.

[0056] In this application, the solubility of the supercritical fluid in the polymer foam product can be regulated by adjusting the pressure and temperature of the supercritical fluid impregnation. The solubility of the supercritical fluid in the polymer foam product (%) = (m2-m1) x 100% / m1; wherein m1 is the mass of the polymer part, and m2 is the mass of the polymer foam product.

[0057] In the supercritical foaming process, the plasticizing effect of the supercritical fluid can reduce the softening point of the polymer. Long-term supercritical fluid impregnation can cause the polymer part to creep under the action of its own gravity. By controlling the solubility of the supercritical fluid, the temperature and time of the supercritical fluid impregnation, the polymer part can be prevented from creeping during the supercritical fluid impregnation and foaming process, and a polymer foam product with low compression permanent deformation, high tensile strength and high resilience can be obtained.

[0058] As a foaming method, pressure relief foaming or temperature rise foaming can be used; or the temperature rise foaming can be performed by introducing a hot medium, which can be air or hot water vapor.

[0059] Specifically, the pressure relief rate of the pressure relief foaming is 50-100 MPa / s, for example, it can be but is not limited to 50 MPa / s, 60 MPa / s, 70 MPa / s, 80 MPa / s, 90 MPa / s, 100 MPa / s.

[0060] In some embodiments, at least one of the following conditions is met: (a) the thermoplastic elastomer comprises 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), olefin block copolymer (OBC); Specifically, the thermoplastic polyester elastomer refers to a linear block copolymer containing polybutylene terephthalate (PBT) polyester hard segment and aliphatic polyester or polyether soft segment; Specifically, as examples of polyamides, PA6, PA12, PA66, PA610, PA612, PA6I, PA6T, PEBA (polyether amide block copolymer) can be listed; (b) the foaming agent comprises at least one of CO2 fluid, N2 fluid, flammable alkane, azodicarbonamide, carbonate, N, N-dinitrosopentamethylenetetramine; (c) the nucleating agent comprises at least one of calcium carbonate, talcum powder, mica, montmorillonite, nanosilica, carbon black, carbon nanotube; (d) the color masterbatch comprises organic dye; (e) the matting agent comprises at least one of sorbitol monopalmitate, xylitol ester; (f) the lubricant comprises at least one of polyethylene wax, stearic acid, lead stearate, zinc stearate, paraffin wax.

[0061] The production method of the thermoplastic resin mixture material of the present application is not particularly strictly limited, and a blending device such as a mixer is used. The order of addition between components is not particularly strictly limited, and simultaneous addition or addition in a certain order can be adopted, and two or more components can be selected from all components to be pre-mixed, for example, color masterbatch, matting agent and lubricant, etc. can be pre-formed into a masterbatch, and then added to other components in the form of the masterbatch according to the set proportion, and mixed. The resin used in the masterbatch can be the thermoplastic elastomer described in the present application.

[0062] In some embodiments, the planning path of 3D printing comprises at least one of a grid structure, a tetrahedron structure, a straight line structure, a triangular structure, an internal hexagonal structure, a cubic structure, a cubic partition structure, an octagonal structure, a concentric circle structure, a zigzag structure, a cross structure, a cross 3D structure, a helical icosahedron structure, a lightning-shaped structure, and a reinforced frame, wherein the grid structure comprises at least one of an in-plane grid structure and an interlayer grid structure. In the specific embodiments of the present application, the above structures are all structures provided in the 3D printing software.

[0063] In the second aspect of the present application, a polymer foam product is provided, which is prepared by the preparation method of the polymer foam product.

[0064] In some embodiments, the apparent density of the polymer foam product is 100-300 kg / m 3 , the resilience is ≥60%, and the compression permanent set is ≤50%.

[0065] Specifically, the apparent density of the polymer foam product can be 100 kg / m 3 , 130 kg / m 3 , 150 kg / m 3 , 180 kg / m 3 , 200 kg / m 3 , 220 kg / m 3 , 250 kg / m3 270 kg / m 3 300 kg / m 3 a range value between any two of the above values; Specifically, the resilience of the polymer foam product can be a range value between any two of 60%, 62%, 65%, 67%, 70%, 73%, 75%, 77%, 80%.

[0066] Specifically, the compression set of the polymer foam product can be a range value between any two of 5%, 7%, 9%, 11%, 13%, 15%, 20%, 23%, 25%, 27%, 30%, 35%, 40%, 45%, 50%.

[0067] Specifically, the apparent density of the polymer foam product is measured by a densimeter.

[0068] Specifically, the average diameter of the cells in the polymer foam product is observed by a scanning electron microscope.

[0069] Specifically, the expansion ratio (%) of the polymer foam product = (S1-S2) / S2x100%; wherein S1 is the length, width or height of the polymer foam product, and S2 is the length, width or height of the polymer product; taking the length direction as an example, S1 is the length of the polymer foam product, and S2 is the length of the polymer product.

[0070] Specifically, the resilience of the polymer foam product is tested by a resilience tester.

[0071] Specifically, the compression set of the polymer foam product is tested by a compression set tester.

[0072] In a third aspect, the application provides a shoe material comprising the polymer foam product.

[0073] The raw materials used in the examples and comparative examples are described as follows, but are not limited to these materials: Thermoplastic elastomer A: polyether TPU, Shore hardness 85A, WHT-8185, Wanhua Chemical; Thermoplastic elastomer B: polyether TPU, Shore hardness 88A, WHT-8885, Wanhua Chemical; Thermoplastic elastomer C: polyether TPU, Shore hardness 90A, WHT-8190, Wanhua Chemical; Thermoplastic elastomer D: polyether TPU, Shore hardness 95A, WHT-8195, Wanhua Chemical; Thermoplastic elastomer E: polyester TPU, Shore hardness 85A, 385SX, Covestro; Thermoplastic elastomer F: TPEE, Shore hardness 45D, Hytrel 4556, Celenisus, USA; Thermoplastic elastomer G: EVA, Shore hardness 85A, Hytrel 1985A, Celenisus, USA; Thermoplastic elastomer H: Polyether TPU, Shore hardness 80A, WHT-8180, Wanhua Chemical; Thermoplastic elastomer I: Polyether TPU, Shore hardness 64D, WHT-8264, Wanhua Chemical; Foaming agent: sodium bicarbonate, commercially available; Color masterbatch: Polybatc, Clariant, commercially available; Matting agent: Xylitol ester, commercially available Lubricant: Polyethylene wax, commercially available; Antioxidant A: N,N-di-sec-butyl-p-phenylenediamine; Antioxidant B: Tris (2,4-di-tert-butylphenyl) phosphite, commercially available; Antioxidant C: Tetra[β-(3,5-di-tert-butyl-4-hydroxyphenyl) propionic acid] pentaerythritol ester, commercially available.

[0074] Example 1 The present embodiment provides a method for preparing a polymer foam product, comprising the following steps: S1: 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 are added into a mixer, and mixed uniformly to obtain a thermoplastic resin mixture; The thermoplastic resin mixture is added into a single screw extruder for melt extrusion to obtain a wire; the temperature for melt extrusion is 200℃; The obtained wire melt is 3D printed according to a planned path to obtain a polymer part; wherein the thickness of the crystal lattice of the polymer part is 2.5mm, and the parameters for 3D printing are as follows: the printing temperature is 210℃; S2: The polymer part obtained in step S1 is placed in a solvent, soaked at a temperature of 30℃ for 15min, and then washed, dried to obtain a pretreated polymer part; wherein the solvent is a mixture of ethanol and acetone, and the volume ratio of ethanol to acetone is 40:60; S3: The pretreated polymer part is placed in an autoclave and subjected to nitrogen fluid immersion, and the obtained immersed polymer part is subjected to pressure relief foaming within 1s to obtain a polymer foam product, wherein the immersion temperature is 130℃, the pressure is 20MPa, the time is 3h, and the solubility of the nitrogen fluid in the polymer foam product is 1%.

[0075] Example 2 This example provides a method of making a polymer foam product, which differs from Example 1 by using thermoplastic elastomer B in place of thermoplastic elastomer A.

[0076] Example 3 This example provides a method of making a polymer foam product, which differs from Example 1 by using thermoplastic elastomer C in place of thermoplastic elastomer A.

[0077] Example 4 This example provides a method of making a polymer foam product, which differs from Example 1 by using thermoplastic elastomer D in place of thermoplastic elastomer A.

[0078] Example 5 This example provides a method of making a polymer foam product, which differs from Example 1 by using thermoplastic elastomer E in place of thermoplastic elastomer A.

[0079] Example 6 This example provides a method of making a polymer foam product, which differs from Example 1 by using thermoplastic elastomer F in place of thermoplastic elastomer A.

[0080] Example 7 This example provides a method of making a polymer foam product, which differs from Example 1 by using thermoplastic elastomer G in place of thermoplastic elastomer A.

[0081] Example 8 This example provides a method of making a polymer foam product, which differs from Example 1 by using a polymer article having a cell thickness of 3 mm.

[0082] Example 9 This example provides a method of making a polymer foam product, which differs from Example 1 by using a polymer article having a cell thickness of 1 mm.

[0083] Example 10 This example provides a method of making a polymer foam product, which differs from Example 1 by using a polymer article having a cell thickness of 0.5 mm.

[0084] Example 11 This example provides a method of making a polymer foam product, which differs from Example 1 by using a polymer article having a cell thickness of 5 mm.

[0085] Example 12 This example provides a method for preparing a polymer foam product, which is different from Example 1 in that antioxidant B is used instead of antioxidant A.

[0086] Example 13 This example provides a method for preparing a polymer foam product, which is different from Example 1 in that antioxidant C is used instead of antioxidant A.

[0087] Example 14 This example provides a method for preparing a polymer foam product, which is different from Example 1 in that the mass ratio of ethanol and acetone is 30:70.

[0088] Example 15 This example provides a method for preparing a polymer foam product, which is different from Example 1 in that the mass ratio of ethanol and acetone is 25:75.

[0089] Example 16 This example provides a method for preparing a polymer foam product, which is different from Example 1 in that the mass ratio of ethanol and acetone is 45:55.

[0090] Example 17 This example provides a method for preparing a polymer foam product, which comprises the following steps: S1: 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 matte agent, 5 parts by weight of lubricant, 0.1 parts by weight of nucleating agent and 1 parts by weight of antioxidant A are added to a mixer and mixed uniformly to obtain a thermoplastic resin mixture; The thermoplastic resin mixture is added to a single screw extruder for melt extrusion to obtain a wire melt; the temperature for melt extrusion is 200°C; The obtained wire melt is 3D printed according to a planned path to obtain a polymer part; wherein the thickness of the crystal lattice of the polymer part is 2.5 mm, and the parameters for 3D printing are as follows: the printing temperature is 220°C; S2: The polymer part obtained in step S1 is placed in a solvent and soaked at a temperature of 10°C for 30 min, and then washed and dried to obtain a pretreated polymer part; wherein the solvent is a mixture of ethanol and acetone, and the volume ratio of ethanol to acetone is 60:40; S3: The pretreated polymer part is placed in an autoclave and subjected to nitrogen fluid immersion, and the obtained immersed polymer part is subjected to pressure relief foaming within 1 s to obtain a polymer foam product, wherein the immersion temperature is 120°C, the pressure is 30 MPa, the time is 0.5 h, and the solubility of the nitrogen fluid in the polymer foam product is 3%.

[0091] Example 18 The present example provides a method for preparing a polymer foam product, comprising the following steps: S1: 90 parts by weight of thermoplastic elastomer A, 1 part by weight of foaming agent, 10 parts by weight of color masterbatch, 0.1 part by weight of matte agent, 0.1 part by weight of lubricant, 1 part by weight of nucleating agent and 0.1 part by weight of antioxidant A are added into a mixer, mixed uniformly to obtain a thermoplastic resin mixture; The thermoplastic resin mixture is added into a single screw extruder for melt extrusion to obtain a wire melt; the temperature for melt extrusion is 200℃; The obtained wire melt is 3D printed according to a planned path to obtain a polymer part; wherein the parameters for 3D printing are as follows: the thickness of the lattice of the polymer part is 2.5mm, and the printing temperature is 210℃; S2: the polymer part obtained in step S1 is placed in a solvent, soaked at a temperature of 50℃ for 5min, then washed and dried to obtain a pretreated polymer part; wherein the solvent is a mixture of ethanol and acetone, and the volume ratio of ethanol to acetone is 60:40; S3: the pretreated polymer part is placed in an autoclave and subjected to nitrogen fluid impregnation, and the obtained impregnated polymer part is subjected to pressure relief foaming within 1s to obtain a polymer foam product, wherein the impregnation temperature is 40℃, the pressure is 10MPa, the time is 6h, and the solubility of the nitrogen fluid in the polymer foam product is 0.5%.

[0092] Example 19 The present example provides a method for preparing a polymer foam product, which is different from example 1 in that the thermoplastic resin mixture comprises the following raw materials by weight: 85 parts by weight of thermoplastic elastomer A, 5 parts by weight of color masterbatch, 5 parts by weight of matte agent, 2 parts by weight of lubricant, 0.5 parts by weight of nucleating agent and 0.3 parts by weight of antioxidant A, i.e. the thermoplastic resin mixture does not contain a foaming agent.

[0093] Comparative Example 1 The present comparative example provides a method for preparing a polymer foam product, which is different from example 1 in that it does not contain step S2.

[0094] Comparative Example 2 The present comparative example provides a method for preparing a polymer foam product, which is different from example 1 in that in step S1, thermoplastic elastomer H is used instead of thermoplastic elastomer A.

[0095] Comparative Example 3 The present comparative example provides a method for preparing a polymer foam product, which is different from example 1 in that in step S1, thermoplastic elastomer I is used instead of thermoplastic elastomer A.

[0096] Comparative Example 4 This comparative example provides a method for preparing a polymer foam product, which is different from Example 1 in that in step S1, the thickness of the crystal lattice of the polymer part is 0.1 mm.

[0097] Comparative Example 5 This comparative example provides a method for preparing a polymer foam product, which is different from Example 1 in that in step S1, the thickness of the crystal lattice of the polymer part is 6 mm.

[0098] Comparative Example 6 This comparative example provides a method for preparing a polymer foam product, which is different from Example 1 in that the mass ratio of ethanol and acetone is 55:45.

[0099] Comparative Example 7 This comparative example provides a method for preparing a polymer foam product, which is different from Example 1 in that the mass ratio of ethanol and acetone is 15:85.

[0100] Comparative Example 8 This comparative example provides a method for preparing a polymer foam product, which is different from Example 1 in that the temperature of the soaking is 5°C.

[0101] Comparative Example 9 This comparative example provides a method for preparing a polymer foam product, which is different from Example 1 in that the temperature of the soaking is 60°C.

[0102] Comparative Example 10 This comparative example provides a method for preparing a polymer foam product, which is different from Example 1 in that no antioxidant is added.

[0103] Performance Test The polymer parts and polymer foam products obtained in the examples and comparative examples are subjected to performance tests, and the test methods are as follows: (1) Apparent density: obtained by an automatic water density meter; (2) Resilience: measured by a falling ball resilience tester according to GB / T 6670-2008 standard; (3) Tensile strength: measured by a universal material testing machine, stretched to break at a speed of 300 mm / min, and the breaking strength is taken as the tensile strength; (4) Compression permanent set: measured by a compression permanent set tester, after the sample is compressed to 50% strain, placed in a 50°C oven for 3 h, then taken out, and then the sample is placed at room temperature for 1 h, and then the thickness of the recovered sample is measured, and the compression permanent set is obtained by dividing the recovered thickness by the initial thickness; (5) Appearance: visually observed.

[0104] The test results are shown in Table 1.

[0105] Table 1 From the experimental data in Table 1, it can be seen that the apparent density of the polymer foam product of the present application is 100-300 kg / m 3 , the resilience is ≥60%, the tensile strength is ≥10 MPa, and the compression permanent set is ≤35%.

[0106] From the experimental data of Examples 1-4 and Comparative Examples 2-3, it can be seen 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 ≥16 MPa, and the compression permanent set is ≤22.5%, which 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 permanent set.

[0107] From the experimental data of Example 1 and Examples 8-11, it can be seen that when the thickness of the lattice of the polymer piece is 1-3 mm, the resilience of the obtained polymer foam product is ≥63%, the tensile strength is ≥14 MPa, and the compression permanent set is ≤27%, which indicates that when the thickness of the lattice of the polymer piece is 1-3 mm, the resilience and tensile strength of the polymer foam product can be further improved, and the compression permanent set of the polymer foam product is reduced.

[0108] From the experimental data of Example 1 and Examples 12-13, it can be seen that when the antioxidant is a hindered amine antioxidant, the tensile strength of the obtained polymer foam product is ≥15 MPa, and the compression permanent set is ≤25%, which indicates that when the antioxidant is a hindered amine antioxidant, the polymer foam product has higher tensile strength and lower compression permanent set.

[0109] From the experimental data of Example 1, Examples 14-16, and Comparative Examples 6-7, it can be seen that when the volume ratio of alcohol to acetone is (40:60)-(30:70), the resilience of the obtained polymer foam product is ≥62%, the tensile strength is ≥14 MPa, and the compression permanent set is ≤28%, which indicates that when the volume ratio of alcohol to acetone is (40:60)-(30:70), the polymer foam product has higher tensile strength and resilience and lower compression permanent set.

[0110] Finally, it should be noted that the above examples are used to illustrate the technical solutions of the present disclosure and not to limit the protection scope of the present disclosure. Although the present disclosure has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that the technical solutions of the present disclosure can be modified or equivalently replaced without departing from the essence and scope of the technical solutions of the present 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, 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; 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; And / or, the alcohol includes at least one of monohydric alcohols and polyhydric alcohols.

6. 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; And / or, the supercritical fluid includes at least one of CO2 fluid and N2 fluid; And / or, the solubility of the supercritical fluid in the polymer foam product is 0.5-8%.

7. The method for preparing the polymer foam product 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, polyamide, 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.

8. A polymer foam product, prepared by the method for preparing the polymer foam product according to any one of claims 1-7.

9. The polymer foam product as described in claim 8, characterized in that, The apparent density of the polymer foam product is 100-300 kg / m³. 3 Rebound rate ≥60%, compression set ≤50%.

10. A shoe material, characterized in that, Including the polymer foam products as described in claim 8 or 9.

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