A supercritical foaming midsole material with high rebound response speed and preparation method thereof

Abstract

This invention provides a supercritical foam midsole material with high rebound response speed and its preparation method, belonging to the field of footwear products. The supercritical foam midsole material is formed from formulated raw materials through supercritical foaming. The formulated raw materials include the following components by mass fraction: more than 98% polycaprolactone-type polyurethane; 0.1-0.3% anti-hydrolysis agent; 0.1-0.5% ultraviolet absorber; and 0.1-0.5% antioxidant. While ensuring the lightweight nature of the midsole material, this invention achieves extreme rebound efficiency and rapid deformation recovery capability, thereby effectively cushioning the ground reaction force during exercise, reducing the potential damage to the feet and joints from sports impacts, and bringing unprecedented comfort and protection to sports enthusiasts.

Description

Technical Field

[0001] This invention belongs to the field of footwear products, and particularly relates to a supercritical foamed midsole material with high rebound response speed and its preparation method. Background Technology

[0002] In the rapidly developing field of modern sports, the performance of sports equipment has a crucial impact on athletes' performance and the experience of ordinary sports enthusiasts. For footwear, traditional sports equipment materials such as EVA (ethylene-vinyl acetate copolymer), while meeting basic requirements for comfort and durability to a certain extent, still have significant shortcomings in rebound speed, responsiveness, and lightweighting. With continuous technological advancements and increasingly higher consumer demands for quality, developing higher-performance sports equipment sole materials has become an urgent need in the industry.

[0003] As a cutting-edge materials processing method, supercritical physical foaming technology has attracted widespread attention in recent years in fields such as sports equipment materials. This technology utilizes the unique properties of supercritical fluids (such as high solubility and low viscosity) to form a uniform and dense microporous structure within the material, thereby endowing footwear materials with excellent properties such as lightweight, high resilience, sound insulation, heat insulation, and shock absorption. Compared with traditional chemical foaming technology, supercritical physical foaming technology is more environmentally friendly and efficient, and can better control the cell structure, improving the overall performance of the material.

[0004] Chinese patent document CN 112120351 A discloses a method for producing one-piece molded footwear. This method involves impregnating and saturating thermoplastic elastomer particles with a supercritical gas, followed by depressurization. This process forms a foamed midsole component while simultaneously bonding the various footwear components. The shoe last is then removed to obtain the complete shoe. This method utilizes supercritical physical technology and offers high production efficiency; however, the rebound response speed of the foamed midsole component still needs further improvement. Summary of the Invention

[0005] In view of this, the present invention provides a supercritical foamed midsole material with high rebound response speed and its preparation method. The present invention strives to achieve extreme rebound efficiency and rapid deformation recovery ability while ensuring the lightweight of the midsole material, thereby effectively buffering the ground reaction force during exercise, reducing the potential damage to the feet and joints caused by sports impact, and bringing an unprecedented comfort and protection experience to sports enthusiasts.

[0006] This invention provides a supercritical foam midsole material with high rebound response speed. The supercritical foam midsole material is formed from formulated raw materials through supercritical foaming, and the formulated raw materials include the following components by mass fraction:

[0007] Over 98% of polycaprolactone-based polyurethanes;

[0008] 0.1-0.3% anti-hydrolysis agent;

[0009] 0.1-0.5% ultraviolet absorber;

[0010] 0.1-0.5% antioxidants.

[0011] In an embodiment of the present invention, the monomers for synthesizing the polycaprolactone-type polyurethane include: 63-64 wt% polycaprolactone diol, 23-24 wt% HDI, 9-10 wt% butanediol and 3-4 wt% neopentyl glycol.

[0012] In an embodiment of the present invention, the anti-hydrolysis agent is a polycarbodiimide-based anti-hydrolysis agent, and the mass fraction of the anti-hydrolysis agent is 0.1-0.2%.

[0013] In an embodiment of the present invention, the ultraviolet absorber is N-(2-ethoxyphenyl)-N'-(2-ethylphenyl)-ethylenediamide, and the mass fraction of the ultraviolet absorber is 0.2-0.3%.

[0014] In an embodiment of the present invention, the antioxidant is antioxidant XH-245, and the mass fraction of the antioxidant is 0.2-0.3%.

[0015] In an embodiment of the present invention, the compression recovery rate of the supercritical foamed midsole material is 750-770 mm / s.

[0016] In an embodiment of the present invention, the hardness of the supercritical foamed midsole material is 36-42C.

[0017] This invention provides a method for preparing the supercritical foamed midsole material as described above, comprising the following steps:

[0018] Using supercritical fluid as a foaming agent, the foaming agent is dissolved in the formulation raw materials under supercritical conditions, and then expansion is induced through a decompression process to obtain the supercritical foamed midsole material.

[0019] The raw materials in the formulation include the following components by mass fraction:

[0020] Over 98% of polycaprolactone-based polyurethanes;

[0021] 0.1-0.3% anti-hydrolysis agent;

[0022] 0.1-0.5% ultraviolet absorber;

[0023] 0.1-0.5% antioxidants.

[0024] In embodiments of the present invention, the supercritical fluid is carbon dioxide or nitrogen.

[0025] The continuous advancement of materials science has provided strong support for the research and development of high-performance sports equipment materials. This invention, by integrating advanced materials science and supercritical physical foaming technology, has pioneered the development of a high-performance supercritical foamed midsole material. The formulation of this supercritical foamed midsole material includes: over 98 wt% polycaprolactone-type polyurethane; 0.1-0.3 wt% anti-hydrolysis agent; 0.1-0.5 wt% ultraviolet absorber; and 0.1-0.5% antioxidant. Firstly, this invention employs a special formulation and supercritical physical foaming technology, enabling the material to rapidly and fully absorb energy when subjected to external forces and recover its deformation in a very short time. This instant rebound performance greatly enhances the wearer's athletic experience and reduces fatigue during exercise. Secondly, the midsole material of this invention has an extremely fast response speed, initiating the rebound process almost simultaneously with impact. This rapid response helps to more effectively disperse and mitigate the impact of exercise, thereby protecting the wearer's feet and joints and reducing the risk of sports injuries. Finally, the high rebound response speed of the midsole material of this invention ensures that it maintains stable performance even after repeated use, and is not prone to aging or performance degradation, thus guaranteeing the long-term durability of the midsole material. In summary, the high rebound response speed midsole material of this invention provides a solution for higher-performance products in related fields. Detailed Implementation

[0026] To provide a clearer understanding of the technical features, objectives, and effects of the present invention, the technical solution of the present invention will now be described in detail with reference to specific embodiments. The described embodiments are only some embodiments of the present invention, and not all embodiments.

[0027] This invention provides a supercritical foamed midsole material with high rebound response speed, which is formed by supercritical foaming of formulated raw materials, wherein the formulated raw materials include the following components by mass fraction:

[0028] Over 98% of polycaprolactone-based polyurethanes;

[0029] 0.1-0.3% anti-hydrolysis agent;

[0030] 0.1-0.5% ultraviolet absorber;

[0031] 0.1-0.5% antioxidants.

[0032] The midsole material described in this invention is a novel supercritical foamed midsole material that integrates high rebound, rapid response, and durability. It can solve the shortcomings of traditional sports equipment materials in terms of rebound speed, response sensitivity, and long-term durability, thereby significantly improving the wearing comfort and protective performance of sports shoes and other sports equipment.

[0033] The midsole material described in this invention is a foamed material formed by supercritical foaming of the formulated raw materials. The main component of the formulated raw materials is polycaprolactone-type polyurethane, and its mass content is more than 98%, preferably greater than or equal to 99%, and further 99.1-99.7%, such as 99.2%, 99.3%, 99.4%, 99.5%, etc.

[0034] Polyurethane is short for polyurethane resin, abbreviated as PU in English. Its synthesis mainly involves the reaction of isocyanate and polyol. Cast polyurethane elastomer, abbreviated as CPU, is widely used; thermoplastic polyurethane elastomer, abbreviated as TPU, is another type. In the unique raw material formulation design of this invention, polycaprolactone-type polyurethane, a polyester thermoplastic polyurethane elastomer, is used as the base material. Special additives such as anti-hydrolysis agents and antioxidants are added in a scientifically proportioned manner to form a unique composite system. This formulation optimizes the physical properties and chemical stability of the midsole material, ensuring the effective arrangement and cross-linking of molecular chains during supercritical foaming, laying the foundation for the material's excellent resilience.

[0035] Preferably, the monomers used in the synthesis of the polycaprolactone-type polyurethane include: 63-64 wt% polycaprolactone diol, 23-24 wt% HDI, 9-10 wt% butanediol, and 3-4 wt% neopentyl glycol. More specifically, the monomers used are: 63.8% polycaprolactone diol, 23.5% HDI, 9.2% butanediol, and 3.5% neopentyl glycol. HDI is an aliphatic isocyanate, which is beneficial for obtaining polyurethane elastomers with good weather resistance and flexibility. The polycaprolactone-type polyurethane can be a commercially available product, such as Guangzhou Shunli Company's H793 model, with a melt index of 5-10 g / 10 min (test conditions: 190℃, 2.16 kg weight).

[0036] In embodiments of the present invention, the formulation raw materials include 0.1-0.3% by mass of an anti-hydrolysis agent, preferably 0.1-0.2% by mass. The anti-hydrolysis agent is preferably a polycarbodiimide-based anti-hydrolysis agent, specifically having a melting point of 70-90°C and a density of approximately 1.05 g / cm³. 3 Solid content ≥99%, commercially available products are acceptable.

[0037] Furthermore, the raw material formulation includes the following components by mass fraction: 0.1-0.5% ultraviolet absorber and 0.1-0.5% antioxidant. The ultraviolet absorber is preferably N-(2-ethoxyphenyl)-N'-(2-ethylphenyl)-ethylenediamide, also known as ultraviolet absorber UV-312, with the chemical structure shown below; the mass fraction of the ultraviolet absorber is preferably 0.2-0.3%, and it possesses characteristics such as good thermal stability.

[0038]

[0039] In a preferred embodiment of the present invention, the antioxidant is antioxidant XH-245, and the mass fraction of the antioxidant is 0.2-0.3%. The chemical name of antioxidant XH-245 is triethylene glycol ether-di(3-tert-butyl-4-hydroxy-5-methylphenyl)propionate, which is mainly used to extend the lifespan of polymer materials and inhibit or delay oxidative degradation. This embodiment of the present invention refines the molecular chain structure of the midsole material, optimizing the molecular structure to ensure that the molecular chains maintain an appropriate balance of flexibility and rigidity during foaming. This optimization not only improves the material's rebound speed and response sensitivity but also significantly enhances the material's fatigue resistance and long-term stability.

[0040] This invention, through the scientifically proportioned ratio of polymers and special additives, allows for precise control of the molecular structure and physical properties of the midsole material, achieving optimal material performance. This refined control not only helps improve the rebound speed and responsiveness of the midsole material but also significantly enhances its durability, extending the lifespan of sports equipment. In this invention, the high-rebound-response supercritical foamed midsole material not only effectively improves the wearing comfort and protective performance of sports shoes and other sports equipment but also brings revolutionary innovative solutions to the sporting goods industry, driving the sustainable development of the entire industry.

[0041] This invention provides a method for preparing the supercritical foamed midsole material as described above, comprising the following steps:

[0042] Using a supercritical fluid (such as carbon dioxide or nitrogen) as a foaming agent, the foaming agent is dissolved in the above-mentioned formulation raw materials under supercritical conditions, and then expansion is induced through a decompression process to obtain the supercritical foamed midsole material.

[0043] The components in the raw material formulation are as described above; in this embodiment of the invention, the formulated raw materials are placed in a supercritical foaming processing device, and a foaming agent such as carbon dioxide or nitrogen is dissolved in the material under supercritical conditions. The process conditions for dissolving the supercritical fluid foaming agent include: pressure of 40-50 MPa, temperature of 130-160℃, and time of 60-150 min.

[0044] Subsequently, in this embodiment of the invention, expansion is induced through a decompression process to obtain the supercritical foamed midsole material. This embodiment of the invention, through precise control of the material's molecular structure and supercritical material foaming technology, prepares a novel supercritical foamed midsole material with excellent immediate rebound performance, rapid response, and the ability to recover its deformation in a very short time, significantly improving the wearer's athletic experience and comfort.

[0045] In some embodiments of the present invention, the compression recovery rate of the supercritical foamed midsole material is 750-770 mm / s. Furthermore, the hardness of the supercritical foamed midsole material can be 36-42C (room temperature test). This invention, through the organic combination of unique formulated raw materials and supercritical physical foaming technology, has successfully developed a novel supercritical foamed midsole material with significant high rebound response speed, excellent resilience and durability, bringing a revolutionary innovative solution to the sporting goods industry, and possessing enormous market potential and application prospects.

[0046] To further understand the present invention, the following detailed description is provided in conjunction with embodiments. The scope of protection of the present invention is not limited to the following embodiments. Furthermore, experimental methods not specifying specific experimental conditions are conventional methods and conditions well known in the art.

[0047] The monomers used in the synthesis of the polycaprolactone-type polyurethane include: 63.8 wt% (molar ratio 7.3%) of polycaprolactone diol, 23.5 wt% of HDI (molar ratio 50.0%), 9.2 wt% of butanediol (molar ratio 30.6%), and 3.5 wt% (molar ratio 12.1%) of neopentyl glycol; it is model H793 from Guangzhou Shunli Company, with a melt index of 5-10 g / 10 min (test conditions 190℃, 2.16 kg weight).

[0048] Example 1

[0049] The preparation method of the supercritical foamed midsole material includes the following steps:

[0050] Using supercritical fluid as a foaming agent, carbon dioxide is dissolved in the formulation raw materials under supercritical conditions, and then expansion is induced through a decompression process to obtain the supercritical foamed midsole material. The process conditions for dissolving the supercritical fluid foaming agent include: pressure of 40-50 MPa, temperature of 140-150℃, and time of 120 min.

[0051] The raw materials in the formulation include the following components by mass fraction:

[0052] 99.4% polycaprolactone-based polyurethane;

[0053] 0.2% anti-hydrolysis agent;

[0054] 0.2% UV absorber;

[0055] 0.2% antioxidant.

[0056] The anti-hydrolysis agent is a polycarbodiimide-based anti-hydrolysis agent with a melting point of 70-90℃ and a density of approximately 1.05 g / cm³. 3 Solid content ≥99%.

[0057] The ultraviolet absorber is N-(2-ethoxyphenyl)-N'-(2-ethylphenyl)-ethylenediamide; the antioxidant is antioxidant XH-245.

[0058] The performance of the supercritical foamed midsole sample from Example 1 was tested, and the results are as follows.

[0059] Table 1. Performance test results of the midsole sample from Example 1

[0060]

[0061]

[0062] Abrasion resistance test: GB / T 3903.2-2017 (peeled). Various impact damping tests: J4003; Rebound and damping performance test: J4004; Fatigue compression performance test: J4011 1.3KN, 3.8Hz, 100,000 cycles. Color fastness test: J52, Method B is UV lamp, continuous irradiation for 3 hours; Method C is spotlight, irradiation distance 0.5m, continuous irradiation for 72 hours. Aging resistance test: J53 Method A, 70℃, 95%RH, 72 hours. Hardness test: J56 Ascar C; some tests are conducted immediately after low-temperature (0~15℃, 2 hours) pretreatment, with low-temperature hardness (left and right, MD upper and MD lower): 41~47. Strength test: J57 Method C; Compression deformation test: J59 Method A, 50℃, 6 hours. Density test: J60 Method A; Shrinkage performance test: J64 Method B, 70℃, 20min. Delamination tear strength test: J83; Rebound rate test: J86.

[0063] In addition, the sole samples were tested with both left and right feet; some also had a two-layer MD structure.

[0064] Table 2 Comparative Study Data on Rebound Response Speed ​​of Supercritical Foamed Midsole Materials

[0065]

[0066] The national standard method code is GB / T30907. The test is performed 30 times, and the average value of the last 5 test data is taken.

[0067] Example 2

[0068] Similar to Example 1, the preparation method of the supercritical foamed midsole material includes the following steps:

[0069] Using supercritical fluid as a foaming agent, carbon dioxide is dissolved in the formulation raw materials under supercritical conditions, and then expansion is induced by a decompression process to obtain the supercritical foamed midsole material.

[0070] The raw materials in the formulation include the following components by mass fraction:

[0071] 99.3% polycaprolactone-based polyurethane;

[0072] 0.1% anti-hydrolysis agent;

[0073] 0.3% UV absorber;

[0074] 0.3% antioxidant.

[0075] As can be seen from the above embodiments, the supercritical foamed midsole material prepared in the embodiments of the present invention has broad application prospects in sports shoes and other fields, and can effectively reduce the impact of sports and protect the feet and joints. The embodiments of the present invention, by optimizing the molecular structure and foaming process of the midsole material, achieve a perfect combination of its rebound performance and durability, providing a high-performance material solution for related fields.

[0076] The above examples are only used to illustrate the technical features and implementation process of the present invention, and are not intended to limit the technical solutions of the present invention. It should be noted that those skilled in the art can still make modifications or equivalent substitutions to the present invention without departing from the principle of the present invention, and all such modifications or substitutions are covered by the protection of the present invention.

Claims

1. A supercritical foamed midsole material with high rebound response speed, characterized in that, The supercritical foamed midsole material is formed from formulated raw materials through supercritical foaming, and the formulated raw materials include the following components by mass fraction: Over 98% of polycaprolactone-based polyurethanes; 0.1-0.3% anti-hydrolysis agent; 0.1-0.5% ultraviolet absorber; 0.1-0.5% antioxidant; The sum of the mass fractions of all components in the formula raw materials is 100%; The monomers for synthesizing the polycaprolactone-type polyurethane include: 63-64 wt% polycaprolactone diol, 23-24 wt% HDI, 9-10 wt% butanediol, and 3-4 wt% neopentyl glycol.

2. The supercritical foamed midsole material according to claim 1, characterized in that, The anti-hydrolysis agent is a polycarbodiimide-based anti-hydrolysis agent, and the mass fraction of the anti-hydrolysis agent is 0.1-0.2%.

3. The supercritical foamed midsole material according to claim 1, characterized in that, The ultraviolet absorber is N-(2-ethoxyphenyl)-N'-(2-ethylphenyl)-ethylenediamide, and the mass fraction of the ultraviolet absorber is 0.2-0.3%.

4. The supercritical foamed midsole material according to claim 1, characterized in that, The antioxidant is antioxidant XH-245, and the mass fraction of the antioxidant is 0.2-0.3%.

5. The supercritical foamed midsole material according to any one of claims 1-4, characterized in that, The compression recovery rate of the supercritical foamed midsole material is 750-770 mm / s.

6. The supercritical foamed midsole material according to claim 5, characterized in that, The hardness of the supercritical foamed midsole material is 36-42C.

7. A method for preparing the supercritical foamed midsole material according to any one of claims 1-6, comprising the following steps: Using supercritical fluid as a foaming agent, the foaming agent is dissolved in the formulation raw materials under supercritical conditions, and then expansion is induced through a decompression process to obtain the supercritical foamed midsole material. The raw materials in the formulation include the following components by mass fraction: Over 98% of polycaprolactone-based polyurethanes; 0.1-0.3% anti-hydrolysis agent; 0.1-0.5% ultraviolet absorber; 0.1-0.5% antioxidant; The sum of the mass fractions of all components in the formula is 100%.

8. The preparation method according to claim 7, characterized in that, The supercritical fluid is carbon dioxide or nitrogen.

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