A non-Newtonian fluid shoe midsole material and its preparation method

Abstract

The present invention discloses a non-Newtonian fluid shoe midsole material and a preparation method thereof. A non-Newtonian fluid shoe midsole material is prepared by kneading, foaming and granulating materials. The materials, by mass parts, include: 35-50 parts of paraffin oil, 20-40 parts of starch, 10-20 parts of hydrogenated styrene-butadiene block copolymer, 5-10 parts of silicon dioxide, 20-30 parts of ethylene-vinyl acetate copolymer, 1-2 parts of crosslinking agent, and 3-5 parts of foaming agent. The present invention provides a non-Newtonian fluid shoe midsole material and a preparation method thereof, which meet the requirements of sports shoes for mechanics and density and also maintain the characteristics of a good non-Newtonian fluid.

Description

Technical Field

[0001] The present invention relates to the field of sports shoe sole materials, and in particular to a non-Newtonian fluid shoe midsole material and a preparation method thereof. Background Art

[0002] As we all know, non-Newtonian fluid materials are materials that work on the principle of anti-Newtonian fluids. They possess unique dynamic mechanical properties. When the shear force acting on the fluid changes, its viscosity also changes. Simply put, the relationship between the material and the impact force is that it becomes stronger when it is strong and weaker when it is weak. This characteristic can meet the dual dynamic and static needs of consumers during exercise. During running, the downward impact force is large, so the sole has stronger support and rebound. During daily walking, the downward impact force is small, so the sole is softer and more comfortable. The application of non-Newtonian fluid materials in the midsoles of sports shoes has greatly improved the cushioning performance of the midsoles, but it has also significantly increased the weight of the soles. Published patents and literature often feature materials with densities greater than or close to 1.0 g / cm³, which exhibit non-Newtonian fluid characteristics. These materials not only fail to meet the lightweight and density requirements of athletic shoes, but also impose a significant weight burden on consumers while running, limiting their widespread adoption in the athletic shoe industry. Alternatively, materials with non-Newtonian fluid properties are added to other formula components, resulting in the final product essentially losing its non-Newtonian fluid characteristics. This is because non-Newtonian fluids have a unique molecular structure, and if this structure is disrupted, the non-Newtonian fluid properties are effectively lost. Therefore, finding a cushioning material that possesses both non-Newtonian fluid characteristics and a mechanical and density structure that meets the requirements of athletic shoes is an urgent issue facing the athletic shoe industry. Summary of the Invention

[0003] The purpose of the present invention is to overcome the above-mentioned defects or problems existing in the background technology and provide a non-Newtonian fluid shoe midsole material and a preparation method thereof, which can meet the mechanical and density requirements of sports shoes while maintaining good non-Newtonian fluid characteristics.

[0004] To achieve the above object, the present invention adopts the following technical solutions:

[0005] The first technical solution relates to a non-Newtonian fluid shoe midsole material, which is made by mixing, foaming and granulating materials; the materials include, by mass: 35-50 parts of paraffin oil, 20-40 parts of starch, 10-20 parts of hydrogenated styrene-butadiene block copolymer, 5-10 parts of silica, 20-30 parts of ethylene-vinyl acetate copolymer, 1-2 parts of a crosslinking agent, and 3-5 parts of a foaming agent.

[0006] The second technical solution is based on the first technical solution. Among them, the paraffin oil selected has a kinematic viscosity of less than 45 mm2 / s at 100 °C and a product number of 15-45.

[0007] The third technical solution is based on the first technical solution. Among them, the starch selected is one or several of cassava starch, corn starch, and potato starch; among them, the fineness of the starch is more than 400 mesh, and the starch content exceeds 99%.

[0008] The fourth technical solution is based on the first technical solution. Among them, the hydrogenated styrene-butadiene block copolymer selected is a product with a hard segment content of 13% to 33%.

[0009] The fifth technical solution is based on the first technical solution. Among them, the silica selected is a product prepared by the precipitation method with a fineness of more than 800 mesh.

[0010] The sixth technical solution is based on the first technical solution. Among them, the ethylene-vinyl acetate copolymer selected is a product with a vinyl acetate content exceeding 40%.

[0011] The seventh technical solution is based on the first technical solution. Among them, the cross-linking agent selected is the odorless peroxide cross-linking agent bis(tert-butylperoxy) diethylbenzene.

[0012] The eighth technical solution is based on the first technical solution. Among them, the foaming agent selected is the dinitrosopentamethylenetetramine foaming agent added with the auxiliary agent urea fat, and its decomposition temperature is 120 °C to 125 °C.

[0013] The ninth technical solution is based on the preparation method of a non-Newtonian fluid shoe midsole material according to any one of the first to eighth technical solutions, including the following steps: Step 1, weighing materials: Weigh the first group of materials and the second group of materials according to parts by weight. The first group of materials is ethylene-vinyl acetate copolymer, starch, silica, and foaming agent, and the second group of materials is paraffin oil and hydrogenated styrene-butadiene block copolymer; Step 2, kneading: Let the second group of materials stand for 4 to 6 hours. After the paraffin oil is dissolved in the hydrogenated styrene-butadiene block copolymer, pour the first group of materials into the kneading machine. When the temperature rises to between 55-65 degrees, pour the second group of materials. When the temperature rises to 70-80 degrees, pour out the kneaded materials; Step 3, foaming: Pour the kneaded materials into a single-screw foaming machine. The temperatures of the first zone, the second zone, and the third zone are adjusted to 90 degrees, 100 degrees, and 120 degrees respectively. Among them, the screw speed is adjusted to 15-20 revolutions per minute; Step 4, pelletizing: Pour the foamed materials into a pelletizing machine. The temperatures of the first zone, the second zone, the third zone, and the fourth zone are adjusted to 75 degrees, 80 degrees, 85 degrees, and 90 degrees respectively. Among them, the screw speed is adjusted to 40-50 revolutions per minute, and the cutting speed is adjusted to 15-20 revolutions per minute.

[0014] As can be seen from the above description of the present invention, compared with the prior art, the present invention has the following beneficial effects:

[0015] 1. Materials with a "linear molecular structure" are easily prepared into non-Newtonian fluid materials when mixed with an appropriate amount of liquid; this formulation selects two common materials with a "linear molecular structure" in daily life, one is linear molecular paraffin oil, and the other is amylose; since linear molecular paraffin oil is itself a liquid, it can be used as both a linear material and a liquid mixing agent. Since linear molecular materials usually have poor fracture and tensile mechanics, a certain degree of fracture and tensile mechanics is required in the sports shoe industry. To solve the problem of poor fracture and tensile mechanics of linear molecular materials in the preparation, a hydrogenated styrene-butadiene block copolymer (SEBS) material that is completely compatible with paraffin oil is selected to improve the fracture and tensile mechanics of the preparation and meet the tensile mechanics required for sports shoes; at the same time, to prevent the easy accumulation and precipitation of amylose, an appropriate amount of silica is added during the preparation to prevent starch accumulation and precipitation; secondly, to reduce the density of this preparation, an ethylene-vinyl acetate copolymer (EVA) with a high vinyl acetate (VA) content is added in an appropriate amount, and a low-temperature foaming agent and a crosslinking agent are proportioned for crosslinking and foaming, so that the density of this preparation is reduced to 0.14 - 0.5 g / cm3.

[0016] 2. This formulation uses paraffin oil as the fluid of the non-Newtonian fluid material. Compared with using silicone oil as the fluid, it not only has a lower cost advantage but is also easier to operate during the preparation process; at the same time, since linear molecular paraffin oil is itself a liquid, it can be used as both a linear material and a liquid mixing agent; the paraffin oil selected has a kinematic viscosity of less than 45 mm2 / s at 100 °C and is easily compatible with other components.

[0017] 3. Starch is a high-molecular carbohydrate and can be compatible with a variety of organic and inorganic compounds. In the formula of this patent, starch is dispersed in the mixture in a certain proportion. When the dispersion is subjected to an external impact force, the starch molecules will suddenly aggregate together and become hard, possessing solid characteristics. When there is no impact force on the surface, it is very soft, and it is the key material for the composition to form non-Newtonian fluid characteristics. Starch with a fineness mesh number greater than 400 is selected. The larger the mesh number, the more uniform the dispersion.

[0018] 4. Hydrogenated styrene-butadiene block copolymer, with the full English name Styrene Ethylene Butylene Styrene, abbreviated as SEBS, is a linear triblock copolymer with a polystyrene end segment and an ethylene-butene copolymer obtained by hydrogenating polybutadiene as the middle elastic block; styrene is the hard segment of SEBS, which has strong rigidity and has the most important influence on the properties of SEBS; as the styrene content increases, the hardness and strength of the elastomer will increase, but the elasticity will decrease; a hard segment content of 13-33% meets the requirements of both hardness and elasticity. Since linear molecular materials usually have poor fracture and tensile mechanics, a certain degree of fracture and tensile mechanics is required in the sports shoe industry. To solve the problem of poor fracture and tensile mechanics of linear molecular materials in the preparation, a hydrogenated styrene-butadiene block copolymer (SEBS) material that is completely compatible with paraffin oil is selected to improve the fracture and tensile mechanics of the preparation and meet the tensile mechanics required for sports shoes.

[0019] 5. To prevent the easy accumulation and precipitation of amylose, an appropriate amount of silica is added during the preparation to prevent starch from accumulating and precipitating; the silica selected is a product prepared by the precipitation method with a fineness of more than 800 mesh. The larger the mesh number, the more uniform the dispersion.

[0020] 6. Ethylene-vinyl acetate copolymer, with the full English name Ethylene-vinyl Acetate, abbreviated as EVA. The high vinyl acetate (VA) content determines the flexibility and elasticity of EVA. A product with 40% high vinyl acetate (VA) is more flexible and has better elasticity. An appropriate amount of ethylene-vinyl acetate copolymer (EVA) with a high vinyl acetate (VA) content is added, and a foaming agent and a crosslinking agent are proportioned for crosslinking and foaming. Not only does it maintain the softness of the material, but it also reduces the density of this preparation to 0.14 - 0.5 g / cm3. Finally, the density of the material is greatly reduced, and it has a lower cost advantage, thus enabling it to meet the requirements for large-area use in the sports shoe field.

[0021] 7. A crosslinking agent is a substance that can bridge between linear molecules, causing multiple linear molecules to bond to each other to form a network structure, promoting or regulating the formation of covalent bonds or ionic bonds between polymer molecules. In this patent, the odorless peroxide crosslinking agent bis(tert-butylperoxy) diethylbenzene is used to crosslink the various component materials in the formula to form a network structure material, improving the comprehensive mechanical properties of the material.

[0022] 8. The blowing agent used is dinitrosopentamethylenetetramine, abbreviated as blowing agent H, and an auxiliary agent, urea ester component, abbreviated as "H + urea ester", is added thereto; the urea ester is a carbamide ester obtained by the reaction of urea and organic acid and is pulverized and classified by an air jet mill, which solves the problem of production instability caused by the hygroscopicity of urea; since the decomposition temperature of blowing agent H is high and the residue after foaming has an odor, it cannot be used alone; after adding the urea ester auxiliary agent, the decomposition temperature of blowing agent H can be effectively reduced by 120°C to 125°C, and the odor remaining after the decomposition of blowing agent H can be effectively removed.

[0023] 9. This preparation method is simple in operation and easy to implement. The process equipment used is the existing traditional equipment in the midsole industry of sports shoes. Therefore, the preparation of this product can be completed by using the existing equipment in the midsole industry, and no additional equipment is required for mass production. Detailed implementation mode

[0024] Next, the technical solutions in the embodiments of the present invention will be clearly and completely described in conjunction with the embodiments of the present invention. Obviously, the described embodiments are the preferred embodiments of the present invention and should not be regarded as excluding other embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present invention.

[0025] In the claims and the specification of the present invention, unless otherwise clearly defined, when using terms such as "first", "second", or "third", etc., they are all used to distinguish different objects and are not used to describe a specific order.

[0026] In the claims and the specification of the present invention, unless otherwise clearly defined, for orientation words, when using terms such as "center", "horizontal", "longitudinal", "level", "vertical", "top", "bottom", "inner", "outer", "upper", "lower", "front", "rear", "left", "right", "clockwise", "counterclockwise", etc. to indicate the orientation or position relationship, it is only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation or be constructed and operated in a specific orientation, so it cannot be understood as limiting the specific protection scope of the present invention.

[0027] In the claims, the specification and the drawings of the present invention, unless otherwise clearly defined, when using terms such as "fixed connection" or "fixedly connected", it should be understood in a broad sense, that is, any connection method without displacement relationship and relative rotation relationship between the two, that is, including non-detachable fixed connection, detachable fixed connection, being integrally connected, and being fixedly connected through other devices or elements.

[0028] In the claims and the specification of the present invention, when terms such as "comprising", "having" and their variants are used, they are intended to mean "including but not limited to".

[0029] An embodiment of the present invention provides a non-Newtonian fluid shoe midsole material, which is prepared by kneading, foaming and granulating materials; the materials, by mass, include: 35-50 parts of paraffin oil, 20-40 parts of starch, 10-20 parts of hydrogenated styrene-butadiene block copolymer, 5-10 parts of silica, 20-30 parts of ethylene-vinyl acetate copolymer, 1-2 parts of crosslinking agent, and 3-5 parts of foaming agent; wherein, paraffin oil and starch are two common materials with "linear molecular structure" in daily life, and are easy to be prepared into non-Newtonian fluid materials when mixed with an appropriate amount of liquid.

[0030] Specifically, the paraffin oil selected has a kinematic viscosity less than 45 mm2 / s at 100 °C and a grade of 15-45; preferably, the selected varieties are paraffin oils No. 15, No. 26 and No. 45 produced by Sinopec; in this embodiment, the paraffin oil selected is paraffin oil No. 26 produced by Sinopec. This formulation uses paraffin oil as the fluid of the non-Newtonian fluid material. Compared with using silicone oil as the fluid, it not only has a lower cost advantage, but is also easier to operate during the preparation process; at the same time, since the linear molecular paraffin oil itself is a liquid, it can be used both as a linear material and as a liquid mixing agent; the paraffin oil selected has a kinematic viscosity less than 45 mm2 / s at 100 °C and is easily compatible with other components.

[0031] The starch is selected from one or more of tapioca starch, corn starch and potato starch; wherein, the fineness of the starch is more than 400 mesh and the starch content exceeds 99%; in this embodiment, corn starch is selected and any commercially available variety can be used; starch is a common material with "linear molecular structure" and is easy to be made into non-Newtonian fluid materials. Starch is a high molecular carbohydrate and can be compatible with a variety of organic and inorganic compounds. In the formula of this patent, starch is dispersed in the mixture in a certain proportion. When the dispersion is subjected to an external impact force, the starch molecules will suddenly aggregate together and become hard, showing solid characteristics. When there is no impact force on the surface, it is very soft. It is the key material for the composition to form non-Newtonian fluid characteristics. Starch with a fineness of more than 400 mesh is selected. The larger the mesh number, the more uniform the dispersion.

[0032] The hydrogenated styrene-butadiene block copolymer used is a product with a hard segment content of 13% to 33%; the hydrogenated styrene-butadiene block copolymer, with the full English name Styrene Ethylene Butylene Styrene, abbreviated as SEBS, is a linear triblock copolymer with a polystyrene end segment and an ethylene-butene copolymer obtained by hydrogenating polybutadiene as the middle elastic block; styrene is the hard segment of SEBS and has strong rigidity, which has the most important impact on the performance of SEBS; as the styrene content increases, the hardness and strength of the elastomer will increase, but the elasticity will decrease; a hard segment content of 13-33% meets the requirements of both hardness and elasticity. Since linear molecular materials usually have poor fracture and tensile mechanics, and a certain degree of fracture and tensile mechanics is required in the sports shoe industry, in order to solve the problem of poor fracture and tensile mechanics of linear molecular materials in the preparation, a hydrogenated styrene-butadiene block copolymer (SEBS) material that is completely compatible with paraffin oil is selected to improve the fracture and tensile mechanics of the preparation and meet the tensile mechanics required for sports shoes. Specifically, SEBS can be selected as YH503T and YH688 produced by Yueyang Petrochemical; in this example, SEBS selected is YH503T produced by Yueyang Petrochemical.

[0033] The precipitated silica used is a product with a fineness of more than 800 mesh; in order to prevent the problem of easy accumulation and precipitation of amylose, an appropriate amount of precipitated silica is added during the preparation to prevent the starch from accumulating and precipitating; precipitated silica with a fineness of more than 800 mesh is selected, and the larger the mesh number, the more uniform the dispersion. Specifically, the precipitated silica can be selected as CL-178 produced by Hunan Zhuzhou Silica Factory or Degussa VN3; in this example, the precipitated silica can be selected as CL-178 produced by Hunan Zhuzhou Silica Factory.

[0034] The ethylene-vinyl acetate copolymer used is a product with a vinyl acetate content exceeding 40%; the ethylene-vinyl acetate copolymer, with the full English name Ethylene-vinyl Acetate, abbreviated as EVA, a high vinyl acetate (VA) content determines the flexibility and elasticity of EVA, and a product with 40% high vinyl acetate (VA) is more flexible and has better elasticity. An appropriate amount of ethylene-vinyl acetate copolymer (EVA) with a high vinyl acetate (VA) content is added, and a foaming agent and a crosslinking agent are proportioned for crosslinking and foaming, which not only maintains the softness of the material, but also reduces the density of this preparation to 0.14 - 0.5 g / cm3. Finally, the density of the material is greatly reduced, and it has a lower cost advantage, so that it can meet the requirements for large-area use in the sports shoe field; specifically, EVA can be selected as Dupont 40W or Arkema 40-50; in this example, the selected EVA is Dupont 40W.

[0035] The crosslinking agent selected is the odorless peroxide crosslinking agent bis(tert-butylperoxy) diisopropylbenzene. A crosslinking agent is a substance that can bridge between linear molecules, enabling multiple linear molecules to bond with each other to form a network structure, promoting or regulating the formation of covalent bonds or ionic bonds between polymer molecules. In this patent, the odorless peroxide crosslinking agent bis(tert-butylperoxy) diisopropylbenzene is used to crosslink the various constituent materials in the formulation to form a network structure material, enhancing the comprehensive mechanical properties of the material. Specifically, the crosslinking agent can be selected from Aksa 14L-FS or Arkema F-FLAKES; in this embodiment, the crosslinking agent selected is Aksa 14L-FS.

[0036] The blowing agent selected is the dinitrosopentamethylenetetramine blowing agent with the additive urea ester, and its decomposition temperature is 120°C to 125°C. The blowing agent selected is dinitrosopentamethylenetetramine, abbreviated as blowing agent H, with the additive urea ester component added, abbreviated as "H + urea ester". Urea ester is a carbonamide ester obtained by the reaction of urea with organic acids and is pulverized and classified by an air jet mill, solving the problem of production instability caused by the hygroscopicity of urea. Since the decomposition temperature of blowing agent H is high and the residue after foaming has an odor and cannot be used alone, adding the urea ester additive can effectively reduce the decomposition temperature of blowing agent H to 120°C to 125°C and effectively remove the odor remaining after the decomposition of blowing agent H. Specifically, the blowing agent can be selected from 130B or 130A produced by Fujian Honghai Fine Chemicals; in this embodiment, the blowing agent selected is Fujian Honghai Fine Chemicals 130B.

[0037] The preparation method of the low-density non-Newtonian fluid shoe midsole material specifically includes the following steps:

[0038] Step 1, weighing: Weigh the first group of materials and the second group of materials according to parts by weight. The first group of materials is ethylene-vinyl acetate copolymer, starch, silica, and blowing agent, and the second group of materials is paraffin oil and hydrogenated styrene-butadiene block copolymer;

[0039] Step 2, kneading: Let the second group of materials stand for 4 to 6 hours to allow the paraffin oil to dissolve in the hydrogenated styrene-butadiene block copolymer, then pour the first group of materials into a kneader. When the temperature rises to between 55 - 65 degrees, pour in the second group of materials. When the temperature rises to 70 - 80 degrees, pour out the kneaded materials;

[0040] Step 3, foaming: Pour the kneaded materials into a single-screw foaming machine, and adjust the temperatures of the first zone, the second zone, and the third zone to 90 degrees, 100 degrees, and 120 degrees respectively. Among them, the screw speed is adjusted to 15 - 20 revolutions per minute;

[0041] Step 4, material manufacturing: Pour the foamed material into the material manufacturing machine, and adjust the temperatures of the first zone, second zone, third zone, and fourth zone to 75 °C, 80 °C, 85 °C, and 90 °C respectively. Among them, adjust the screw rotation speed to 40 - 50 revolutions per minute, and adjust the cutting speed to 15 - 20 revolutions per minute.

[0042] This preparation method is simple to operate and easy to implement. The process equipment used is the existing traditional equipment in the midsole industry of sports shoes. Therefore, the preparation of this product can be completed using the existing equipment in the midsole industry, without the need for additional investment in equipment to achieve mass production.

[0043] The material with a "linear molecular structure" in this formula is most easily prepared into a non-Newtonian fluid material when mixed with an appropriate amount of liquid. This formula selects two common materials with a "linear molecular structure" in daily life, one is linear molecular paraffin oil, and the other is linear starch. Since linear molecular paraffin oil is itself a liquid, it can be used as both a linear material and a liquid mixing agent. Since linear molecular materials usually have poor fracture and tensile mechanics, a certain degree of fracture and tensile mechanics is required in the sports shoe industry. To solve the problem of poor fracture and tensile mechanics of linear molecular materials in the preparation, a hydrogenated styrene-butadiene block copolymer (SEBS) material that is completely compatible with paraffin oil is selected to improve the fracture and tensile mechanics of the preparation and meet the tensile mechanics required for sports shoes. At the same time, to prevent the easy accumulation and precipitation of linear starch, an appropriate amount of silica is added during the preparation to prevent starch accumulation and precipitation. Secondly, to reduce the density of this preparation, an ethylene-vinyl acetate copolymer (EVA) with a high vinyl acetate (VA) content is added in an appropriate amount, and a low-temperature foaming agent and a crosslinking agent are proportioned for crosslinking and foaming to maintain an appropriate softness and at the same time reduce the density of the product of this preparation to meet the requirements of sports shoes.

[0044] Specifically, the present invention will specifically introduce a preparation of a non-Newtonian fluid midsole material provided by the present application through the following examples. Table 1 shows the mass fractions of the components of the four examples. The preparation is carried out according to the above-mentioned preparation method of a non-Newtonian fluid midsole material. After the preparation is completed, the physical properties of the non-Newtonian fluid midsole materials prepared in each example are detected respectively, and the detection results shown in Table 2 are given, and a comparison is made with the original sample of the non-Newtonian fluid material in Patent CN110951258A from Andafu Company, which is hereinafter referred to as the Andafu comparison sample in Table 2.

[0045] Table 1 Mass fractions of the component compositions of Example 1, Example 2, Example 3, and Example 4

[0046]

[0047]

[0048] Among them, paraffin oil: is the No. 26 paraffin white oil produced by Sinopec;

[0049] Starch: is corn starch, with a fineness mesh number greater than 400 and a starch content exceeding 99%, and any commercially available variety can be used;

[0050] SEBS: is the SEBS503T variety produced by Yueyang Petrochemical;

[0051] EVA: is DuPont 40W;

[0052] Blowing agent: is Fujian Honghai Fine Chemicals 130B;

[0053] Crosslinking agent: is AkzoNobel 14L-FS;

[0054] Silica: is CL-178 produced by Hunan Zhuzhou Silica Factory;

[0055] The preparation method is carried out according to the above steps of weighing materials, kneading, foaming and pelletizing.

[0056] Table 2 Comparison of the physical property test results of the products prepared in Example 1, Example 2, Example 3 and Example 4 with the comparative sample

[0057]

[0058] Note: The data in Table 2 are obtained according to the national standard test method.

[0059] Comparing the densities measured in Comparative Examples 1 to 4, the density of the non-Newtonian fluid prepared by the present invention is only between 0.14 - 0.52 g / cm3, which is 50 - 80% lighter than the density of the comparative sample.

[0060] Comparing the hardnesses measured in Comparative Examples 1 to 4, 39C to 50C is exactly the softness requirement range of the sports shoe industry, and the hardness is increased by 39 - 78% compared with the comparative sample.

[0061] Comparing the rebounds measured in Comparative Examples 1 to 4, which are 40% to 55%, the present invention has better resilience compared with the comparative sample.

[0062] Comparing the delamination tears measured in Comparative Examples 1 to 4, which are 1.5 - 2 N / CM, the present invention has better tear resistance compared with the comparative sample.

[0063] It can be seen that, compared with the existing non-Newtonian fluid midsole materials, the present invention incorporates an ethylene-vinyl acetate copolymer (EVA) with a moderate high vinyl acetate (VA) content in the formulation, and proportions a low-temperature foaming agent and a cross-linking agent for cross-linking and foaming. Not only does it maintain the softness of the material, but also makes the density of the material much lower than that of the existing non-Newtonian fluid comparison samples. Ultimately, the density of the material is greatly reduced, while maintaining the characteristics of a good non-Newtonian fluid. Moreover, the preparation process uses existing process equipment, and the preparation method is simple to operate and easy to implement, with a lower cost advantage, thus enabling the large-scale use requirements in the sports shoe field to be achieved.

[0064] In summary, the present invention provides a non-Newtonian fluid midsole material and a preparation method thereof, which meet the requirements of sports shoes for mechanics and density, and also maintain the characteristics of a good non-Newtonian fluid.

[0065] The above description of the specification and embodiments is used to explain the protection scope of the present invention, but does not constitute a limitation on the protection scope of the present invention. Through the inspiration of the present invention or the above embodiments, those of ordinary skill in the art, in combination with common general knowledge, ordinary technical knowledge in the art, and / or existing technologies, can obtain modifications, equivalent replacements, or other improvements to the embodiments of the present invention or some of its technical features through logical analysis, reasoning, or limited experiments, and all should be included within the protection scope of the present invention.

Claims

1. A non-Newtonian fluid shoe midsole material, characterized in that, It is prepared from materials through kneading, foaming and granulation; the materials, by mass parts, include: 35 - 50 parts of paraffin oil, 20 - 40 parts of starch, 10 - 20 parts of hydrogenated styrene-butadiene block copolymer, 5 - 10 parts of silicon dioxide, 20 - 30 parts of ethylene-vinyl acetate copolymer, 1 - 2 parts of crosslinking agent, and 3 - 5 parts of foaming agent; wherein, the paraffin oil is a straight-chain molecular paraffin oil, the starch is amylose, the hydrogenated styrene-butadiene block copolymer is a product with a hard segment content of 13 - 33%, the ethylene-vinyl acetate copolymer is a product with a vinyl acetate content exceeding 40%, and the foaming agent is a dinitrosopentamethylenetetramine foaming agent added with an auxiliary agent urea resin.

2. The non-Newtonian fluid shoe midsole material according to claim 1, characterized in that, The kinematic viscosity of the paraffin oil at 100 °C is less than 45 mm 2 / s.

3. The non-Newtonian fluid shoe midsole material according to claim 1, characterized in that, The starch is selected from one or more of tapioca starch, corn starch and potato starch; wherein, the fineness of the starch is more than 400 mesh, and the starch content exceeds 99%.

4. The non-Newtonian fluid insole material according to claim 1, characterized in that, The silicon dioxide is a product prepared by the precipitation method with a fineness of more than 800 mesh.

5. The non-Newtonian fluid insole material according to claim 1, characterized in that, The crosslinking agent is an odorless peroxide crosslinking agent bis(tert-butylperoxy) diethylbenzene.

6. The non-Newtonian fluid shoe midsole material according to claim 1, characterized in that, The decomposition temperature of the foaming agent is 120°C to 125°C.

7. A preparation method of a non-Newtonian fluid shoe midsole material as described in any one of claims 1 to 6, characterized in that, It includes the following steps: Step 1, weighing materials: Weigh the first group of materials and the second group of materials respectively according to the weight parts. The first group of materials is ethylene-vinyl acetate copolymer, starch, silicon dioxide and foaming agent, and the second group of materials is paraffin oil and hydrogenated styrene-butadiene block copolymer. Step 2, kneading: Let the second group of materials stand for 4 to 6 hours. After the paraffin oil is dissolved in the hydrogenated styrene-butadiene block copolymer, pour the first group of materials into a kneader. When the temperature rises to between 55 - 65 degrees, pour in the second group of materials. When the temperature rises to 70 - 80 degrees, pour out the kneaded materials. Step 3, foaming: Pour the kneaded materials into a single-screw foaming machine. The temperatures of the first zone, the second zone and the third zone are adjusted to 90 degrees, 100 degrees and 120 degrees respectively. Among them, the screw speed is adjusted to 15 - 20 revolutions per minute. Step 4, granulating: Pour the foamed materials into a granulator. The temperatures of the first zone, the second zone, the third zone and the fourth zone are adjusted to 75 degrees, 80 degrees, 85 degrees and 90 degrees respectively. Among them, the screw speed is adjusted to 40 - 50 revolutions per minute, and the cutting speed is adjusted to 15 - 20 revolutions per minute.

Images