CN-121991398-A - 3D printing supercritical foaming high-support foam sole material and preparation process thereof

CN121991398ACN 121991398 ACN121991398 ACN 121991398ACN-121991398-A

Abstract

The invention discloses a 3D printing supercritical foaming high-support foam sole material and a preparation process thereof in the technical field of high polymer materials, which takes ethylene-vinyl acetate copolymer as a matrix, the composite wire suitable for fused deposition molding is prepared by introducing mesoporous silica coated carbon nanotube hybrid and phosphorus-nitrogen synergistic flame-retardant enhanced titanium dioxide nanorod two functional modifiers and melt blending. And precisely printing a small-size blank by using a fused deposition 3D printing technology, and then performing saturated permeation and controlled foaming by using supercritical nitrogen or carbon dioxide fluid to uniformly expand and shape the blank so as to obtain the foam sole with a fine and dense cell structure. The invention overcomes the defect that the traditional mould pressing foaming is difficult to realize the personalized complex structure, and the obtained product has high support, high rebound resilience, excellent flame retardant property and ultraviolet light stability while realizing remarkable light weight, thereby providing a brand new solution for manufacturing the high-performance personalized sports sole.

Inventors

LU YOULIANG
Zhuo dongxian
LU YOUGUANG
QU BO

Assignees

福建嘉怡新材料科技有限公司

Dates

Publication Date: 20260508
Application Date: 20260318

Claims (10)

1. The preparation process of the 3D printing supercritical foaming high-support foam sole material is characterized by comprising the following steps of: S1, premixing 80-90 parts of ethylene-vinyl acetate copolymer, 5-8 parts of maleic anhydride grafted ethylene-vinyl acetate copolymer, 1-2 parts of ethylene-bis stearamide, 0.3-0.8 part of antioxidant and 2-4 parts of mesoporous silica coated carbon nanotube hybrid and 3-5 parts of phosphorus-nitrogen synergistic flame-retardant reinforced titanium dioxide nanorod by weight parts to obtain premix, feeding the premix into a double-screw extruder, melt blending, extrusion, water cooling and granulating to obtain composite master batch, feeding the composite master batch into a single-screw extruder, plasticizing, stretching by a sizing die head to obtain composite material wires, and printing the composite material wires on an FDM3D printer to obtain a blank; S2, placing the blank body into an autoclave of a supercritical fluid foaming device, sealing, injecting nitrogen or carbon dioxide into the autoclave, heating, pressurizing, releasing pressure, and cooling to room temperature.
2. The process for preparing a 3D printing supercritical foaming high support foam sole material according to claim 1, wherein in the step S1, the melt blending temperature is 130-160 ℃, and the plasticizing temperature is 140-155 ℃.
3. The process for preparing a 3D printing supercritical foaming high support foam sole material according to claim 1, wherein in step S2, the pressure is increased to 15-25MPa.
4. The process for preparing the 3D printing supercritical foaming high-support foam sole material according to claim 1, wherein the preparation method of the mesoporous silica coated carbon nanotube hybrid comprises the following steps: Adding 0.8-1.2 parts of multiwall carbon nanotubes into mixed acid of concentrated sulfuric acid and concentrated nitric acid in parts by weight, performing ultrasonic treatment at 58-62 ℃ to obtain a product, diluting the product with deionized water, washing the product to be neutral, and then performing vacuum drying to obtain acidified carbon nanotubes, dissolving 1.5-2.5 parts of cetyltrimethylammonium bromide into a mixed solution of 300-500 parts of absolute ethyl alcohol and 300-500 parts of deionized water, adding the acidified carbon nanotubes, performing ultrasonic dispersion to obtain a suspension, slowly dropwise adding 8-12 parts of tetraethyl orthosilicate into the suspension under stirring, adjusting the pH value to 8.9-9.1, and performing stirring reaction at 38-42 ℃ to obtain a reaction product; a2, transferring the reaction product into a hydrothermal reaction kettle, performing hydrothermal reaction at 98-102 ℃ to obtain a reaction mixture, performing centrifugal separation and ethanol washing on the reaction mixture, performing vacuum drying at 58-62 ℃ to obtain dried solid, and placing the dried solid into a tube furnace to be calcined at 545-555 ℃ under the protection of nitrogen atmosphere.
5. The process for preparing a 3D printing supercritical foaming high support foam sole material according to claim 4, wherein in the step A1, the ultrasonic treatment is performed at 58-62 ℃ for 4-6h.
6. The process for preparing a 3D printing supercritical foaming high support foam sole material according to claim 4, wherein in the step A2, the calcination time is 5-10h at 545-555 ℃.
7. The process for preparing the 3D printing supercritical foaming high-support foam sole material according to claim 1, wherein the preparation method of the phosphorus-nitrogen synergistic flame-retardant reinforced titanium dioxide nanorod comprises the following steps: Dripping 8-12 parts of tetrabutyl titanate into absolute ethyl alcohol by weight part, stirring to obtain a solution A, mixing 1.8-2.2 parts of glacial acetic acid, 4.5-5.5 parts of deionized water and 25-35 parts of absolute ethyl alcohol to obtain a solution B, dripping the solution B into the solution A under stirring, continuously stirring to obtain a mixed solution, transferring the mixed solution into a high-pressure reaction kettle, carrying out hydrothermal reaction at 175-185 ℃ to obtain a reaction mixture, centrifuging the reaction mixture, washing the reaction mixture with absolute ethyl alcohol and deionized water sequentially, and carrying out vacuum drying at 78-82 ℃ to obtain a titanium dioxide nano rod, dispersing the titanium dioxide nano rod into a mixed solvent of 40-50 parts of ethanol and 2-5 parts of deionized water, adding 0.4-0.6 part of gamma-aminopropyl triethoxysilane, carrying out reflux reaction at 68-72 ℃, carrying out centrifugal separation to obtain a solid, washing the solid with absolute ethyl alcohol, and carrying out vacuum drying to obtain the aminated titanium dioxide nano rod; B2, dispersing the aminated titanium dioxide nano rod in 40-60 parts of 2- (N-morpholino) ethanesulfonic acid buffer solution with the pH value of 5.4-5.6, adding 0.15-0.25 part of 1-ethyl-3- (3-dimethylaminopropyl) carbodiimide hydrochloride and 0.08-0.12 part of N-hydroxysuccinimide, activating at room temperature, adding 0.8-1.2 parts of phytic acid, reacting at room temperature to obtain a product, centrifuging the product, washing the product with deionized water, and drying in vacuum.
8. The process for preparing a 3D printing supercritical foaming high support foam sole material according to claim 7, wherein in the step B1, the time of the reflux reaction is 6-8h at 68-72 ℃.
9. The process for preparing a 3D printing supercritical foaming high support foam sole material according to claim 7, wherein in the step B2, the reaction time is 24-30h at room temperature.
10. A 3D printed supercritical foaming high support foam sole material, characterized in that the 3D printed supercritical foaming high support foam sole material is prepared according to the preparation process of the 3D printed supercritical foaming high support foam sole material of any one of claims 1-9.

Description

3D printing supercritical foaming high-support foam sole material and preparation process thereof Technical Field The invention relates to the technical field of high polymer materials, in particular to a 3D printing supercritical foaming high-support foam sole material and a preparation process thereof. Background Ethylene vinyl acetate copolymer has been widely used for a long time in the manufacture of parts such as athletic shoe midsoles and insoles because of its light weight, softness, excellent cushioning properties and relatively low cost. The main current processing mode in the industry is a compression molding chemical foaming process, namely, an EVA substrate is mixed with auxiliary agents such as a chemical foaming agent, a cross-linking agent and the like and then is placed in a mold for high-temperature and high-pressure vulcanization, so that the foaming agent is decomposed to generate gas, and a cell structure is formed in the sole. However, this conventional process has a number of inherent drawbacks. Firstly, compression molding is highly dependent on a mold, has long development period and high cost, is difficult to realize the personalized sole manufacture with complex curved surfaces, hollowed-out or lattice structures, and cannot meet the requirements of modern consumers on personalized customization and functional structure optimization of sports equipment. Secondly, small molecule byproducts often remain after the decomposition of the chemical foaming agent, which may not only cause burden to the environment, but also make the uniform distribution in the product difficult to control accurately, which easily causes uneven cell size and affects the mechanical property and durability of the sole. In addition, the pure EVA foaming material has relatively limited supporting property, compression deformation resistance and tearing strength, is difficult to provide enough rollover resistance support and long-term stability in high-strength sports such as basketball, and restricts the further application of the pure EVA foaming material in the field of high-performance sports shoes. In recent years, the rapid development of Fused Deposition Modeling (FDM) 3D printing technology has brought new possibilities for footwear manufacturing. The technology forms by stacking thermal fuse materials layer by layer, and has the remarkable advantages of no need of a die, extremely high design freedom degree, capability of rapidly realizing conversion from design to real objects and the like. In the footwear field, FDM technology has been explored for printing customized soles, insoles, etc., that can be precisely adapted according to the individual's foot morphology and movement habits. Meanwhile, the supercritical fluid foaming technology is used as a green physical foaming method, and the high solubility of nitrogen or carbon dioxide to a polymer matrix in a supercritical state and thermodynamic instability caused by rapid pressure relief are utilized to prepare the foam material with uniform foam Kong Ximi and excellent mechanical properties. Currently, supercritical foaming technology is researched to be applied to elastomers such as Thermoplastic Polyurethane (TPU) and the like to prepare high-performance foaming materials, and a new technical path is provided for performance upgrading of the sports shoe soles. Although FDM printing and supercritical foaming techniques each exhibit significant advantages, the efficient combination of the two to produce high performance EVA foam soles still faces key technical challenges. Firstly, FDM printing wires are mostly pure polymers or simple filling modification, and lack of special composite materials designed for a subsequent foaming process, and if a directly printed blank is subjected to supercritical foaming, the problems of insufficient nucleation points of cells, difficult control of foaming multiplying power, coarse or uneven cells and the like often exist. Secondly, sole printed by FDM technology is usually solid structure, and although complex appearance can be realized, the product is thick and heavy, and the special light buffering performance of foaming material is lacking. In addition, how to introduce functional nano reinforcing phase into EVA matrix, ensure good dispersion in printing wire and serve as heterogeneous nucleation point in subsequent foaming process, so as to synchronously realize the light weight, high support, flame retardance, ultraviolet resistance and other additional functions of the sole, which is a difficult problem to be solved in industry. Therefore, the development of an overall technical scheme which can combine the personalized forming capability of FDM3D printing with the high performance advantage of supercritical fluid foaming and overcome the self performance limitation of EVA materials has great significance for promoting the technical progress of manufacturing the sole of high-performance personalized sports s