High-elastic damping foaming material and preparation method thereof

Abstract

The invention discloses a high-elastic damping foaming material and a preparation method thereof. The foaming material comprises the following components in percentage by mass: 15-27% of an ethylene-vinyl acetate copolymer; 8% to 22% of a polyolefin elastomer; 20% to 30% of an olefin block copolymer; 15% to 27% of a hydrogenated styrene-butadiene-styrene block copolymer; 5%-17% of ethylene propylene diene monomer; 0.1% to 1.6% of talcum powder; 0.3% to 0.6% of stearic acid; 0.5% to 1.0% of zinc stearate; 1% to 2% of zinc oxide; 3.5% to 4.5% of titanium dioxide; 0.3% to 1.0% of an odorless bridging agent; 3%-8% of a foaming agent; wherein a molecular chain of the hydrogenated styrene-butadiene-styrene block copolymer comprises a random chain link formed by a styrene structural unit and a hydrogenated butadiene structural unit and a polystyrene micro-block, the glass transition temperature of the hydrogenated styrene-butadiene-styrene block copolymer is in a range of-36.6 DEG C to-34.6 DEG C, and the loss factor at a test frequency of 1 Hz is in a range of 0.95 to 0.98. According to the foaming material, the damping G value can be reduced, and meanwhile, the elasticity of the material is considered.

Description

Technical Field

[0001] The present invention relates to the technical field of foam materials, and in particular to a high-elasticity shock-absorbing foam material and a preparation method thereof. Background Art

[0002] Ethylene-vinyl acetate copolymer (EVA) is a rubber-like thermoplastic. Compared to polyethylene, it offers superior flexibility, low-temperature flexibility, elasticity, stress crack resistance, and good plasticity and processability, leading to its widespread application. EVA has a wide range of applications. EVA foam, with its softness, elasticity, and chemical resistance, is used in the soles and interior trims of mid- to high-end travel shoes, hiking boots, slippers, and sandals.

[0003] Current sports insoles generally use foam materials to provide cushioning and comfort. Peak Gravity (G-value) is a key indicator of shock absorption performance in insoles. The lower the value, the greater the material's ability to absorb and disperse impact, and the better the joint protection. However, existing sports insoles, while reducing G-value, struggle to maintain the same elasticity due to the physical properties of the foam material, resulting in reduced wearing comfort. Summary of the Invention

[0004] The purpose of the present invention is to overcome the above-mentioned defects or problems existing in the background technology and to provide a high-elastic shock-absorbing foam material and a preparation method thereof, which can reduce the shock-absorbing G value while taking into account the elasticity of the material.

[0005] To achieve the above object, the present invention adopts the following technical solutions:

[0006] Technical Solution 1: A high-elastic shock-absorbing foam material, which comprises the following components by mass percentage: 15% to 27% ethylene-vinyl acetate copolymer; 8% to 22% polyolefin elastomer; 20% to 30% olefin block copolymer; 15% to 27% hydrogenated styrene-butadiene-styrene block copolymer; 5% to 17% EPDM rubber; 0.1% to 1.6% talc; 0.3% to 0.6% stearic acid; 0.5% to 1.0% zinc stearate; and 1% zinc oxide. to 2%; titanium dioxide 3.5% to 4.5%; odorless bridging agent 0.3% to 1.0%; foaming agent 3% to 8%; wherein the molecular chain of the hydrogenated styrene-butadiene-styrene block copolymer comprises randomized chain segments formed by styrene structural units and hydrogenated butadiene structural units and polystyrene microblocks, and its glass transition temperature is between -36.6°C and -34.6°C, and the loss factor at a test frequency of 1 Hz is between 0.95 and 0.98.

[0007] Technical Solution 2 based on Technical Solution 1: The glass transition temperature of the hydrogenated styrene-butadiene-styrene block copolymer is -35.6°C, and the loss factor at a test frequency of 1 Hz is 0.966.

[0008] Technical solution three based on technical solution two: the content of vinyl acetate in the ethylene-vinyl acetate copolymer is 20% to 30% by mass.

[0009] Technical solution 4 based on technical solution 3: the polyolefin elastomer is an ethylene-octene copolymer.

[0010] Technical solution 5 based on technical solution 4: the olefin block copolymer is an ethylene-octene block copolymer.

[0011] Technical solution six based on technical solution five: the EPDM rubber is an ethylene-propylene-diene terpolymer with ethylidene norbornene as the third monomer.

[0012] Technical solution seven based on technical solution six: the titanium dioxide is rutile titanium dioxide.

[0013] Technical solution eight based on technical solution seven: the odorless bridging agent is an organic peroxide bridging agent.

[0014] Technical solution nine based on technical solution eight: the foaming agent is an azodicarbonamide foaming agent.

[0015] In addition, the present invention also provides Technical Solution 10: a method for preparing a high-elastic shock-absorbing foam material, which is based on the components of a high-elastic shock-absorbing foam material described in any one of Technical Solutions 1 to 9 and is prepared by the following steps:

[0016] Step 1: Weigh and mix the components according to the weight percentages, and then melt-blend and knead them in a mixer at a temperature of 110° C. to 140° C. for 8 to 15 minutes to form a homogeneous blended material;

[0017] Step 2: mixing the homogeneous blended material uniformly through an open mixing device;

[0018] Step 3: Granulate the material after milling to obtain granular plastic rice;

[0019] Step 4: The granular plastic rice is kept at a temperature of 170° C. to 190° C. for 100 to 150 seconds and foamed by a foaming device to obtain a foam material sheet;

[0020] Step 5: Cool the foam material sheet to set the shape, and let it stand at 25°C for maturation.

[0021] From the above description of the present invention, it can be seen that compared with the prior art, the present invention has the following beneficial effects:

[0022] When designing high-shock-absorbing foam materials, those skilled in the art often face an inherent cognitive dilemma: significantly improving the damping properties of the material (to absorb impact energy) will inevitably lead to a significant decrease in the material's rebound performance, making the material "dead" and lacking the proper "feel"; at the same time, introducing polymers with special functions (such as high damping), especially at higher concentrations, may also cause compatibility issues with the matrix resin, leading to processing difficulties, deterioration of mechanical properties, or uneven pore structure. In addition, constructing a complex blend system containing multiple polymers and expecting it to exhibit synergistic enhancement rather than performance antagonism is itself highly technically challenging. Those skilled in the art often tend to adopt simpler formulas to ensure controllability.

[0023] The high-elasticity shock-absorbing foam material provided by the present invention is formed by compounding a hydrogenated styrene-butadiene-styrene block copolymer having specific molecular structures and physical properties with four polymers, namely, ethylene-vinyl acetate copolymer, polyolefin elastomer, olefin block copolymer, and EPDM rubber, as well as auxiliary components such as talc, stearic acid, zinc stearate, zinc oxide, titanium dioxide, an odorless bridging agent, and a foaming agent, within a specified mass percentage range, thereby forming an organic overall technical solution. The core of this solution lies in the introduction and function of a specific hydrogenated styrene-butadiene-styrene block copolymer. The randomized segments formed by styrene and hydrogenated butadiene units in its molecular chain impart excellent physical compatibility with other main ingredients, such as ethylene-vinyl acetate copolymer, laying the foundation for a uniform and stable blend system, allowing the performance of each component to be effectively utilized rather than weakening each other. Furthermore, the presence of a small number of polystyrene microblocks in its molecular chain forms physical crosslinks during processing and use. This not only helps to improve the material's strength in the molten state, which is crucial for the stability of the cell structure during the subsequent foaming process, but also imparts excellent dimensional stability to the final foamed material, effectively suppressing shrinkage and deformation. More importantly, the specific glass transition temperature (between -36.6°C and -34.6°C) and high loss factor (between 0.95 and 0.98 at a test frequency of 1Hz) of this hydrogenated styrene-butadiene-styrene block copolymer give it excellent impact energy absorption and dissipation capabilities. When impact force acts on the material, this component can efficiently convert mechanical energy into heat energy and dissipate it, which is the physical basis for the material to achieve good shock absorption performance.

[0024] Those skilled in the art would generally expect that the addition of such a high content of high-damping material would seriously sacrifice the material's resilience. However, the present invention produces an unexpected synergistic effect between the specific hydrogenated styrene-butadiene-styrene block copolymer and the polyolefin elastomer (8% to 22%) and olefin block copolymer (20% to 30%) within a limited content range. The polyolefin elastomer, as a highly efficient elasticity modifier, provides excellent elasticity and toughness; while the olefin block copolymer, with its outstanding elastic recovery ability and resistance to permanent compression set, effectively compensates for the elastic loss that may be caused by the high-damping component. This synergistic effect enables the entire material system to maintain good rebound performance while achieving an extremely low shock absorption G value (efficient energy dissipation).

[0025] Among them, ethylene-vinyl acetate copolymer, as the base polymer of the system, provides the necessary softness, good elasticity and processing fluidity within the specified content range. The addition of polyolefin elastomer further significantly enhances the overall elasticity and toughness of the entire material system, improves the mechanical properties of the material in low-temperature environments, and synergizes with the specific hydrogenated styrene-butadiene-styrene block copolymer to jointly enhance the energy absorption capacity of the material. Olefin block copolymers, with their excellent elastic recovery ability and resistance to permanent compression deformation, promote the dimensional stability of the specific hydrogenated styrene-butadiene-styrene block copolymer, ensuring that the foam material can maintain its original shape and cushioning performance after repeated pressure. The introduction of EPDM rubber provides the entire high-performance blend system with excellent weather resistance, ozone resistance and heat aging resistance, ensuring the long-term stability of the insole's shock absorption performance in long-term complex use environments. Auxiliary components such as talc, stearic acid, zinc stearate, zinc oxide, titanium dioxide, odorless bridging agent and foaming agent are within the specified content range, which respectively ensures the uniform and fine pore structure during the foaming process, the smooth processing process, the effective formation of the cross-linking network and the ideal appearance and performance of the final product.

[0026] Therefore, this technical solution effectively solves the technical problems in the existing technology that the shock absorption performance of insole foam materials is difficult to significantly improve, especially the difficulty in stably controlling the shock absorption G value at a low value, while it is difficult to take into account the material elasticity and wearing comfort through the precise coordination and synergy between the above-mentioned components.

[0027] The glass transition temperature of the specific hydrogenated styrene-butadiene-styrene block copolymer is precisely defined at -35.6°C, and its loss factor at a test frequency of 1Hz is precisely defined at 0.966. This more precise parameter definition optimizes the energy dissipation characteristics of the core shock-absorbing component, ensuring that the foam material achieves a more stable and excellent shock-absorbing effect.

[0028] The vinyl acetate content in ethylene-vinyl acetate copolymer is limited to 20% to 30% by mass. As the flexible segment in the ethylene-vinyl acetate copolymer molecular chain, the content of vinyl acetate units directly affects the polymer's softness, elasticity, polarity, and compatibility with other polymers. Controlling the vinyl acetate content within this specific range of 20% to 30% enables the ethylene-vinyl acetate copolymer to exhibit optimal flexibility and elasticity, while also better matching its polarity with other components such as the specific hydrogenated styrene-butadiene-styrene block copolymer, thereby promoting the uniformity and stability of the blend system, which is particularly important for forming a regular cell structure and achieving excellent overall mechanical properties.

[0029] The polyolefin elastomer is limited to ethylene-octene copolymer. As a high-performance polyolefin elastomer, ethylene-octene copolymer is known for its excellent elasticity, toughness, tear strength, and low-temperature performance. Introducing a specific type of ethylene-octene copolymer based on the optimized ethylene-vinyl acetate copolymer in claim 3 can more effectively improve the dynamic mechanical properties and fatigue resistance of the entire foam material, allowing the insole to maintain good rebound and cushioning effects even after long-term repeated stress.

[0030] The olefin block copolymer is limited to ethylene-octene block copolymer. Ethylene-octene block copolymer has a unique molecular structure, with microphase separation of its hard and soft segments forming a physically crosslinked network, endowing the material with excellent elastic recovery, low compression set, and good high-temperature performance. Introducing the ethylene-octene block copolymer into a system already containing specific ethylene-vinyl acetate copolymer and ethylene-octene copolymer can synergize with the physical crosslinks of the specific hydrogenated styrene-butadiene-styrene block copolymer, further enhancing the structural stability and creep resistance of the entire material system, ensuring that the insole maintains its designed shape and shock absorption performance under long-term load-bearing and temperature fluctuations.

[0031] EPDM rubber is defined as an ethylene-propylene-diene terpolymer with ethylidene norbornene as the third monomer. EPDM rubber with ethylidene norbornene as the third monomer exhibits a rapid vulcanization rate and a high crosslink density, capable of forming a highly efficient crosslinked network with an organic peroxide-based bridging agent (as defined in claim 8). In a complex system comprising the aforementioned multiple optimized polymer components, the use of this specific type of EPDM rubber ensures that the entire blend forms a more robust and durable three-dimensional network structure during the foaming and crosslinking processes, thereby significantly improving the foamed material's heat resistance, aging resistance, and tear strength.

[0032] Titanium dioxide is limited to rutile titanium dioxide. Compared to other crystal forms of titanium dioxide, rutile titanium dioxide has a higher refractive index, stronger UV absorption, and superior chemical stability. Using rutile titanium dioxide in foaming materials not only gives the product a whiter, brighter appearance but also significantly improves the material's resistance to UV radiation, thereby delaying the material's aging and degradation caused by light, further enhancing the insole's weather resistance and color durability.

[0033] Odorless bridging agents are limited to organic peroxide-based bridging agents. Organic peroxide-based bridging agents can effectively initiate crosslinking reactions at processing temperatures on double bonds that may exist in ethylene-vinyl acetate copolymers, polyolefin elastomers, EPDM rubber, and certain hydrogenated styrene-butadiene-styrene block copolymers, forming a stable chemical crosslinking network. The formation of this crosslinking network is crucial for improving the elasticity, strength, heat resistance, and compression set resistance of foamed materials. In systems containing multiple specific polymers and rutile titanium dioxide, the use of organic peroxide-based bridging agents ensures the formation of an efficient and uniform crosslinking structure, thereby maximizing the synergistic effects of the various polymer components and ensuring the structural integrity of the foamed material under high temperatures and stresses.

[0034] The foaming agent is limited to azodicarbonamide foaming agents. Azodicarbonamide foaming agents are commonly used chemical foaming agents. Their decomposition temperature, gas production, and other properties can be adjusted through formulation to suit different processing techniques and material systems. In a system that already includes specific polymers, additives, and organic peroxide bridging agents, the use of azodicarbonamide foaming agents, along with precise control of their dosage and processing conditions, allows for a well-matched foaming and cross-linking process, resulting in a uniform, dense, and highly closed-cell foam structure. This optimized foam structure is the physical foundation for achieving lightweight materials, high resilience, and excellent shock absorption properties.

[0035] The present invention also provides a method for preparing the highly elastic shock-absorbing foam material. Based on any of the components described above, the method achieves effective control of the material's microstructure and macroscopic properties through a specific combination of process steps. Step 1 involves weighing, mixing, and melt blending and kneading at a temperature of 110°C to 140°C for 8 to 15 minutes using a banbury mixer. This ensures that the polymer components and additives are fully melted, dispersed, and form a homogeneous blend, which is a prerequisite for the subsequent synergistic effect. Step 2 involves further uniform mixing using an open mixer, enhancing the dispersion of the components. Step 3, granulation, provides a well-formed, easily processable raw material for subsequent foaming and molding. Step 4 involves foaming the granular plastic rice at a temperature of 170°C to 190°C for 100 to 150 seconds. This specific temperature and time window allows for optimal synchronization of foaming and cross-linking, resulting in a foamed structure with an ideal cell density and wall thickness, and imparting a preliminary shape and properties to the material sheet. Step five of cooling and shaping and aging at 25°C helps to release the internal stress generated in the material during processing, stabilize the pore structure, and optimize the final performance of the material. DETAILED DESCRIPTION

[0036] The following is a clear and complete description of the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are preferred embodiments of the present invention and should not be considered as excluding other embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making any creative efforts are within the scope of protection of the present invention.

[0037] In the claims and description of the present invention, if the terms "include", "have" and their variations are used, they are intended to mean "including but not limited to".

[0038] The present invention relates to a high-elasticity shock-absorbing foam material and a preparation method thereof. The high-elasticity shock-absorbing foam material is particularly suitable for use in the preparation of insole products, and comprises the following components in terms of mass percentage:

[0039] Ethylene-vinyl acetate copolymer 15% to 27%; polyolefin elastomer 8% to 22%; olefin block copolymer 20% to 30%; hydrogenated styrene-butadiene-styrene block copolymer 15% to 27%; EPDM rubber 5% to 17%; talc 0.1% to 1.6%; stearic acid 0.3% to 0.6%; zinc stearate 0.5% to 1.0%; zinc oxide 1% to 2%; titanium dioxide 3.5% to 4.5%; odorless bridging agent 0.3% to 1.0%; blowing agent 3% to 8%;

[0040] The molecular chain of the hydrogenated styrene-butadiene-styrene block copolymer comprises randomized chain segments formed by styrene structural units and hydrogenated butadiene structural units, as well as polystyrene microblocks. The glass transition temperature thereof is in the range of -36.6°C to -34.6°C, and the loss factor at a test frequency of 1 Hz is in the range of 0.95 to 0.98.

[0041] Furthermore, as a preferred embodiment, the hydrogenated styrene-butadiene-styrene block copolymer has a glass transition temperature of -35.6°C and a loss factor of 0.966 at a test frequency of 1 Hz.

[0042] The vinyl acetate content of the ethylene-vinyl acetate copolymer is 20% to 30% by mass. The polyolefin elastomer is an ethylene-octene copolymer. The olefin block copolymer is an ethylene-octene block copolymer. The EPDM rubber is an ethylene-propylene-diene terpolymer containing ethylidene norbornene as the third monomer. The titanium dioxide is rutile titanium dioxide. The odorless bridging agent is an organic peroxide bridging agent. The foaming agent is an azodicarbonamide foaming agent.

[0043] In addition, the preparation method of the high-elastic shock-absorbing foam material involved in the present invention is based on the components of the above-mentioned high-elastic shock-absorbing foam material and is prepared by the following steps:

[0044] Step 1: Weigh and mix the components according to the weight percentages, and then melt-blend and knead them in a mixer at a temperature of 110° C. to 140° C. for 8 to 15 minutes to form a homogeneous blended material;

[0045] Step 2: mixing the homogeneous blended material uniformly through an open mixing device;

[0046] Step 3: Granulate the material after milling to obtain granular plastic rice;

[0047] Step 4: The granular plastic rice is kept at a temperature of 170° C. to 190° C. for 100 to 150 seconds and foamed by a foaming device to obtain a foam material sheet;

[0048] Step 5: Cool the foam material sheet to set the shape, and let it stand at 25°C for maturation.

[0049] The high-elastic shock-absorbing foam material and its preparation method involved in the present invention specification are formed by compounding a hydrogenated styrene-butadiene-styrene block copolymer having specific molecular structure and physical properties with four polymers including ethylene-vinyl acetate copolymer, polyolefin elastomer, olefin block copolymer and EPDM rubber, as well as auxiliary components such as talc, stearic acid, zinc stearate, zinc oxide, titanium dioxide, odorless bridging agent and foaming agent within a specified mass percentage range to form an organic overall technical solution. The core of this solution lies in the introduction and function of a specific hydrogenated styrene-butadiene-styrene block copolymer. The randomized segments formed by styrene and hydrogenated butadiene units in its molecular chain impart excellent physical compatibility with other main ingredients, such as ethylene-vinyl acetate copolymer, laying the foundation for a uniform and stable blend system, allowing the performance of each component to be effectively utilized rather than weakening each other. Furthermore, the presence of a small number of polystyrene microblocks in its molecular chain forms physical crosslinks during processing and use. This not only helps to improve the material's strength in the molten state, which is crucial for the stability of the cell structure during the subsequent foaming process, but also imparts excellent dimensional stability to the final foamed material, effectively suppressing shrinkage and deformation. More importantly, the specific glass transition temperature (between -36.6°C and -34.6°C) and high loss factor (between 0.95 and 0.98 at a test frequency of 1Hz) of this hydrogenated styrene-butadiene-styrene block copolymer give it excellent impact energy absorption and dissipation capabilities. When impact force acts on the material, this component can efficiently convert mechanical energy into heat energy and dissipate it, which is the physical basis for the material to achieve good shock absorption performance.

[0050] Those skilled in the art would generally expect that the addition of such a high content of high-damping material would seriously sacrifice the material's resilience. However, the present invention produces an unexpected synergistic effect between the specific hydrogenated styrene-butadiene-styrene block copolymer and the polyolefin elastomer (8% to 22%) and olefin block copolymer (20% to 30%) within a limited content range. The polyolefin elastomer, as a highly efficient elasticity modifier, provides excellent elasticity and toughness; while the olefin block copolymer, with its outstanding elastic recovery ability and resistance to permanent compression set, effectively compensates for the elastic loss that may be caused by the high-damping component. This synergistic effect enables the entire material system to maintain good rebound performance while achieving an extremely low shock absorption G value (efficient energy dissipation).

[0051] Among them, ethylene-vinyl acetate copolymer, as the base polymer of the system, provides the necessary softness, good elasticity and processing fluidity within the specified content range. The addition of polyolefin elastomer further significantly enhances the overall elasticity and toughness of the entire material system, improves the mechanical properties of the material in low-temperature environments, and synergizes with the specific hydrogenated styrene-butadiene-styrene block copolymer to jointly enhance the energy absorption capacity of the material. Olefin block copolymers, with their excellent elastic recovery ability and resistance to permanent compression deformation, promote the dimensional stability of the specific hydrogenated styrene-butadiene-styrene block copolymer, ensuring that the foam material can maintain its original shape and cushioning performance after repeated pressure. The introduction of EPDM rubber provides the entire high-performance blend system with excellent weather resistance, ozone resistance and heat aging resistance, ensuring the long-term stability of the insole's shock absorption performance in long-term complex use environments. Auxiliary components such as talc, stearic acid, zinc stearate, zinc oxide, titanium dioxide, odorless bridging agent and foaming agent are within the specified content range, which respectively ensures the uniform and fine pore structure during the foaming process, the smooth processing process, the effective formation of the cross-linking network and the ideal appearance and performance of the final product.

[0052] Therefore, this technical solution effectively solves the technical problems in the existing technology that the shock absorption performance of insole foam materials is difficult to significantly improve, especially the difficulty in stably controlling the shock absorption G value at a low value, while it is difficult to take into account the material elasticity and wearing comfort through the precise coordination and synergy between the above-mentioned components.

[0053] In order to further illustrate the superiority of the high-elasticity shock-absorbing foam material of the present invention in terms of performance compared with the prior art, the following examples and comparative examples are designed.

[0054] Raw material description:

[0055] Ethylene-vinyl acetate copolymer (EVA): brand EVA7470 (vinyl acetate content 28%, purchased from Polymer Chemicals Co., Ltd.) or the VA content is adjusted according to the examples.

[0056] Polyolefin elastomer (POE): brand POE8150 (ethylene-octene copolymer, purchased from The Dow Chemical Company).

[0057] Olefin block copolymer (OBC): brand OBC9107 (ethylene-octene block copolymer, purchased from The Dow Chemical Company).

[0058] Hydrogenated styrene-butadiene-styrene block copolymer (SEBS-YH): Model SEBS YH530 (glass transition temperature -35.6°C, dissipation factor 0.966 at a test frequency of 1 Hz, molecular chain comprising randomized segments formed by styrene and hydrogenated butadiene structural units, as well as polystyrene microblocks).

[0059] Conventional hydrogenated styrene-butadiene-styrene block copolymer (SEBS-conventional): Commercially available conventional SEBS, such as brand G1650 (available from Kraton), has a loss factor much lower than 0.95.

[0060] Ethylene propylene diene monomer (EPDM): brand EPDM3092 (with ethylidene norbornene as the third monomer, purchased from Mitsui Chemicals).

[0061] Talc: Brand BH818 (purchased from Haicheng Talc Factory).

[0062] Stearic acid: industrial grade.

[0063] Zinc stearate: industrial grade.

[0064] Zinc oxide: indirect method, purity ≥99.7%.

[0065] Titanium dioxide: brand R103 (rutile type, purchased from Chemours).

[0066] Odorless bridging agent: Brand 14S (organic peroxides, such as dicumyl peroxide DCP, purchased from Arkema).

[0067] Foaming agent: Brand AC-3000F (azodicarbonamide, purchased from Yongli Fine Chemical Co., Ltd.).

[0068] Example 1

[0069] The components and their mass percentages are as follows: ethylene-vinyl acetate copolymer (EVA7470, VA content 28%) 21%; polyolefin elastomer (POE8150) 15%; olefin block copolymer (OBC9107) 25%; specific hydrogenated styrene-butadiene-styrene block copolymer (SEBS YH530) 21%; ethylene propylene diene monomer rubber (EPDM3092) 11%; talc (BH818) 0.8%; stearic acid 0.45%; zinc stearate 0.75%; zinc oxide 1.5%; titanium dioxide (R103) 4.0%; odorless bridging agent (14S) 0.65%; foaming agent (AC-3000F) 5.5%.

[0070] Example 2

[0071] The components and their mass percentages are as follows: ethylene-vinyl acetate copolymer (VA content 25%) 27%; polyolefin elastomer (POE8150) 22%; olefin block copolymer (OBC9107) 20%; specific hydrogenated styrene-butadiene-styrene block copolymer (SEBS YH530) 15%; ethylene propylene diene monomer rubber (EPDM3092) 5%; talc (BH818) 0.1%; stearic acid 0.3%; zinc stearate 0.5%; zinc oxide 1.0%; titanium dioxide (R103) 3.5%; odorless bridging agent (14S) 0.3%; and foaming agent (AC-3000F) 3.0%.

[0072] Example 3

[0073] The components and their mass percentages are as follows: 15% ethylene-vinyl acetate copolymer (VA content 22%); 8% polyolefin elastomer (POE8150); 30% olefin block copolymer (OBC9107); 27% specific hydrogenated styrene-butadiene-styrene block copolymer (SEBS YH530); 17% ethylene propylene diene monomer rubber (EPDM3092); 1.6% talc (BH818); 0.6% stearic acid; 1.0% zinc stearate; 2.0% zinc oxide; 4.5% titanium dioxide (R103); 1.0% odorless bridging agent (14S); and 8.0% foaming agent (AC-3000F).

[0074] Example 4

[0075] The components and their mass percentages are as follows: ethylene-vinyl acetate copolymer (VA content 28%) 25%; polyolefin elastomer (POE8150) 18%; olefin block copolymer (OBC9107) 20%; specific hydrogenated styrene-butadiene-styrene block copolymer (SEBS YH530) 20%; ethylene propylene diene monomer rubber (EPDM3092) 10%; the mass percentages of auxiliary materials are: talc (BH818) 0.8%; stearic acid 0.45%; zinc stearate 0.75%; zinc oxide 1.5%; titanium dioxide (R103) 4.0%; odorless bridging agent (14S) 0.65%; and foaming agent (AC-3000F) 5.5%.

[0076] Example 5

[0077] The components and their mass percentages are as follows: ethylene-vinyl acetate copolymer (VA content 20%) 18%; polyolefin elastomer (POE8150) 22%; olefin block copolymer (OBC9107) 23%; specific hydrogenated styrene-butadiene-styrene block copolymer (SEBS YH530) 18%; ethylene propylene diene monomer rubber (EPDM3092) 12%; the mass percentages of auxiliary materials are: talc (BH818) 0.8%; stearic acid 0.45%; zinc stearate 0.75%; zinc oxide 1.5%; titanium dioxide (R103) 4.0%; odorless bridging agent (14S) 0.65%; and foaming agent (AC-3000F) 5.5%.

[0078] Comparative Example 1

[0079] The components and their mass percentages are as follows: ethylene-vinyl acetate copolymer (EVA7470, VA content 28%) 21%; polyolefin elastomer (POE8150) 15%; olefin block copolymer (OBC9107) 25%; conventional hydrogenated styrene-butadiene-styrene block copolymer (SEBS-conventional, G1650) 21%; ethylene propylene diene monomer rubber (EPDM3092) 11%; the mass percentages of auxiliary materials are: talc (BH818) 0.8%; stearic acid 0.45%; zinc stearate 0.75%; zinc oxide 1.5%; titanium dioxide (R103) 4.0%; odorless bridging agent (14S) 0.65%; foaming agent (AC-3000F) 5.5%.

[0080] Comparative Example 2

[0081] The components and their mass percentages are as follows: ethylene-vinyl acetate copolymer (EVA7470, VA content 28%) 37%; polyolefin elastomer (POE8150) 15%; olefin block copolymer (OBC9107) 25%; specific hydrogenated styrene-butadiene-styrene block copolymer (SEBS YH530) 5%; ethylene propylene diene monomer rubber (EPDM3092) 11%; the mass percentages of auxiliary materials are: talc (BH818) 0.8%; stearic acid 0.45%; zinc stearate 0.75%; zinc oxide 1.5%; titanium dioxide (R103) 4.0%; odorless bridging agent (14S) 0.65%; foaming agent (AC-3000F) 5.5%.

[0082] Comparative Example 3

[0083] The components and their weight percentages are as follows: ethylene-vinyl acetate copolymer (EVA7470, 28% VA content) 50%; specific hydrogenated styrene-butadiene-styrene block copolymer (SEBS YH530) 33%; ethylene propylene diene monomer (EPDM3092) 10%; the weight percentages of the auxiliary materials (the total amount may be adjusted to the proportion of the main material or maintained in absolute amounts. The example here uses absolute amounts, but please note that the total does not exceed 100% and should be adjusted proportionally if necessary): talc (BH818) 0.8%; stearic acid 0.45%; zinc stearate 0.75%; zinc oxide 1.5%; titanium dioxide (R103) 4.0%; odorless bridging agent (14S) 0.65%; and foaming agent (AC-3000F) 5.5%. To ensure the total is 100%, the auxiliary materials are adjusted. For example, if the main material accounts for 93%, the auxiliary materials should total 7%, following the original proportions.

[0084] Comparative Example 4

[0085] The components and their mass percentages are as follows: 80% ethylene-vinyl acetate copolymer (EVA7470, VA content 28%); 10% ethylene propylene diene monomer rubber (EPDM3092); 1.0% talc; 0.5% stearic acid; 0.8% zinc stearate; 1.5% zinc oxide; 2.0% titanium dioxide; 0.7% odorless bridging agent; and 3.5% foaming agent.

[0086] Preparation method of foaming material:

[0087] The foaming materials of Examples 1-5 and Comparative Examples 1-4 were prepared using the same method as follows:

[0088] Step 1: Accurately weigh all components according to the mass percentages given in the Examples or Comparative Examples, and briefly premix the powdered additives. Then, add all the main ingredients and premixed additives to an internal mixer, melt blend, and knead at 120°C for 10 minutes to form a homogeneous blend.

[0089] Step 2: The homogeneous blended material obtained in step 1 is transferred to a two-roll mill, further mixed at a roll temperature of 80-100° C., and pressed into sheets.

[0090] Step 3: After the flaky material is cooled after milling, it is granulated by a pelletizer to obtain granular plastic rice.

[0091] Step 4: Take an appropriate amount of the granular plastic and place it in the mold of a flat vulcanizer preheated to 180°C (the mold size is determined according to the test specimen specifications), and foam it for 120 seconds under a pressure of 15 MPa to obtain a foamed material sheet.

[0092] Step 5: Take the foamed material sheet out of the mold, cool it down at room temperature (25°C) to set it in shape, and let it stand at 25°C for 48 hours before performing a performance test.

[0093] Performance testing:

[0094] The following performance tests were performed on the foamed material sheets obtained in the above examples and comparative examples:

[0095] Shock absorption G value: tested in accordance with GB / T 30907-2014 "Test method for shock absorption performance of rubber shoes and sports shoes".

[0096] Hardness: Tested using a Shore C durometer in accordance with GB / T 531.1-2008 "Rubber, vulcanized or thermoplastic — Test method for indentation hardness — Part 1: Shore durometer method (Shore hardness)".

[0097] Rebound resilience: Tested using a pendulum rebound tester in accordance with GB / T 1681-2009 “Determination of rebound resilience of vulcanized rubber”.

[0098] Tensile strength and elongation at break: Tested using standard dumbbell-shaped specimens prepared using a tensile testing machine in accordance with GB / T 528-2009 “Rubber, vulcanized or thermoplastic — Determination of tensile stress-strain properties”.

[0099] Tear strength: Tested in accordance with GB / T 529-2008 “Rubber, vulcanized or thermoplastic — Determination of tear strength (trouser-shaped, right-angled and crescent-shaped test specimens)” (e.g., using a right-angled test specimen).

[0100] Compression set: Tested in accordance with GB / T 7759.1-2015 "Rubber, vulcanized or thermoplastic — Determination of compression set — Part 1: At room and elevated temperatures" (e.g., Method B, 22 hours @ 70°C, 25% compression).

[0101] Test results and analysis:

[0102] Table 1 below lists the performance test results of the foam materials prepared in Examples 1-5 and Comparative Examples 1-4:

[0103]

[0104]

[0105] The above test results show that:

[0106] Compared with Comparative Examples 1, 2, 3, and 4, Examples 1-5 show significant advantages in shock absorption G value, and the G value can reach a lower level (for example, the G value of Example 1 can reach about 8, while the G value of the comparative example is much higher than this).

[0107] The shock absorption G value of Comparative Example 1 (using conventional SEBS) is significantly higher than that of Example 1, which proves the key role of the specific SEBS YH530 used in the present invention in improving the shock absorption performance.

[0108] The shock absorption G value of Comparative Example 2 (significantly reducing the specific SEBS YH530 content) is significantly increased, further confirming the importance of the specific SEBS YH530 content in achieving excellent shock absorption.

[0109] Although Comparative Example 3 (lacking OBC and POE) has a certain shock-absorbing effect due to the presence of the specific SEBS YH530, it is inferior to the examples in terms of resilience, dimensional stability or comprehensive mechanical properties, reflecting the synergistic effect of OBC and POE in the formula.

[0110] The shock absorption G value of Comparative Example 4 (simple EVA system) is higher, but other comprehensive performances cannot be compared with those of the embodiments of the present invention, which highlights the superiority of the five-component main material blending system of the present invention.

[0111] Between Examples 1-5, due to the adjustment of the component content, there are slight changes in the various performance indicators, but they can all be maintained at an excellent level, which proves the universality and stability of the formula of the present invention within a certain range.

[0112] The preparation and performance comparison of the above-mentioned embodiments and comparative examples fully demonstrate that the high-elastic shock-absorbing foam material provided by the present invention, through its unique component selection and scientific proportioning, especially the introduction of hydrogenated styrene-butadiene-styrene block copolymer with specific molecular structure and physical properties, and its effective compounding with a variety of polymers, effectively takes into account the shock-absorbing performance and rebound performance of the foam material. Its application in insole products can bring a good user experience.

[0113] The above description and embodiments are intended to explain the scope of protection of the present invention, but do not constitute a limitation thereto. Modifications, equivalent substitutions, or other improvements to the embodiments of the present invention or portions thereof that can be obtained by a person of ordinary skill in the art through logical analysis, reasoning, or limited experimentation based on the teachings of the present invention or the above embodiments, combined with common knowledge, ordinary technical knowledge in the field, and / or prior art, should all be included within the scope of protection of the present invention.

Claims

1. A high-elastic shock-absorbing foam material, characterized in that: According to mass percentage, it includes the following components: Ethylene-vinyl acetate copolymer 15% to 27%; polyolefin elastomer 8% to 22%; olefin block copolymer 20% to 30%; hydrogenated styrene-butadiene-styrene block copolymer 15% to 27%; EPDM rubber 5% to 17%; talc 0.1% to 1.6%; stearic acid 0.3% to 0.6%; zinc stearate 0.5% to 1.0%; zinc oxide 1% to 2%; titanium dioxide 3.5% to 4.5%; odorless bridging agent 0.3% to 1.0%; blowing agent 3% to 8%; The molecular chain of the hydrogenated styrene-butadiene-styrene block copolymer comprises randomized chain segments formed by styrene structural units and hydrogenated butadiene structural units, as well as polystyrene microblocks. The glass transition temperature thereof is in the range of -36.6°C to -34.6°C, and the loss factor at a test frequency of 1 Hz is in the range of 0.95 to 0.

98.

2. A lightweight, high-gloss, shock-absorbing material as claimed in claim 1, characterized in that: The hydrogenated styrene-butadiene-styrene block copolymer has a glass transition temperature of -35.6° C. and a loss factor of 0.966 at a test frequency of 1 Hz.

3. The lightweight, high-gloss shock-absorbing material according to claim 2, characterized in that: The content of vinyl acetate in the ethylene-vinyl acetate copolymer is 20% to 30% by mass.

4. The lightweight, high-gloss shock-absorbing material according to claim 3, characterized in that: The polyolefin elastomer is ethylene-octene copolymer.

5. The lightweight, high-gloss, shock-absorbing material according to claim 4, characterized in that: The olefin block copolymer is an ethylene-octene block copolymer.

6. The lightweight, high-gloss shock-absorbing material according to claim 5, characterized in that: The EPDM rubber is an ethylene-propylene-diene terpolymer with ethylidene norbornene as the third monomer.

7. The lightweight, high-gloss, shock-absorbing material according to claim 6, characterized in that: The titanium dioxide is rutile titanium dioxide.

8. The lightweight, high-gloss, shock-absorbing material according to claim 7, characterized in that: The odorless bridging agent is an organic peroxide bridging agent.

9. The lightweight, high-gloss, shock-absorbing material according to claim 8, characterized in that: The foaming agent is an azodicarbonamide foaming agent.

10. A method for preparing a high-elastic shock-absorbing foam material, characterized in that: The components of a high-elastic shock-absorbing foam material according to any one of claims 1 to 9 are prepared by the following steps: Step 1: Weigh and mix the components according to the weight percentages, and then melt-blend and knead them in a mixer at a temperature of 110° C. to 140° C. for 8 to 15 minutes to form a homogeneous blended material; Step 2: mixing the homogeneous blended material uniformly through an open mixing device; Step 3: Granulate the material after milling to obtain granular plastic rice; Step 4: The granular plastic rice is kept at a temperature of 170° C. to 190° C. for 100 to 150 seconds and foamed by a foaming device to obtain a foam material sheet; Step 5: Cool the foam material sheet to set the shape, and let it stand at 25°C for maturation.

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