EVA shoe sole material and female shoe sole

Abstract

The application relates to shoes, and particularly discloses an EVA shoe sole material and a female shoe sole. The EVA shoe sole material is prepared from the following raw materials in parts by weight: EVA 100-110 parts; HDPE 12-18 parts; a foaming agent 2-4 parts; a filler 8-12 parts; SEBS 8-12 parts; a matching additive 3-5.5 parts; the matching additive is a calcined powder modified by a silane modifier on the surface, the calcined powder is zinc oxide whisker coated with aluminum oxide, and the particle size of the matching additive is 80-200 nm. Thus, the SEBS is matched with the matching additive, the permanent compression deformation of the shoe sole material is reduced without affecting the shaping of the shoe sole material and without increasing the density and hardness of the shoe sole, and the shoe sole prepared from the EVA shoe sole material has the original lightness and softness of the EVA shoe sole, is not prone to being flat and hard after long-term wearing, and has a good use feeling.

Description

Technical Field

[0001] This invention relates to shoes, and more specifically, to an EVA sole material and a women's shoe sole. Background Technology

[0002] EVA is a commonly used shoe sole material. Compared with rubber and PU, EVA is the lightest. Shoe soles made of EVA foam have good shock absorption and cushioning performance, as well as excellent heat insulation, cold protection, and low-temperature performance.

[0003] However, compared to rubber and PU materials, EVA soles have a greater amount of permanent deformation. After prolonged wear, the soles become compressed, hardened, and flattened, affecting the user's wearing experience. Summary of the Invention

[0004] To address the problem that existing EVA soles tend to harden and flatten after prolonged wear, this invention provides an EVA sole material and a sole made therefrom.

[0005] In a first aspect, the present invention provides an EVA shoe sole material, implemented using the following method:

[0006] An EVA shoe sole material is prepared from the following raw materials in parts by weight:

[0007] 100-110 parts of EVA;

[0008] HDPE 12-18 parts;

[0009] 2-4 parts of foaming agent;

[0010] 8-12 parts of filler;

[0011] 8-12 SEBS;

[0012] Add 3 to 5.5 parts of auxiliary agents;

[0013] The compounding agent is a sintered powder with a surface modified by a silane modifier. The sintered powder is zinc oxide whiskers coated with alumina. The particle size of the compounding agent is 80-200 nm.

[0014] EVA soles harden and flatten over time because EVA material has low density and low strength, resulting in large permanent deformation under long-term pressure. If the strength of EVA material is increased indiscriminately, the EVA soles will be harder and heavier when produced, losing the advantages of EVA material soles being lightweight and soft.

[0015] By adopting the above technical solution, the addition of SEBS alone will reduce the hardness of EVA and affect the shaping of EVA material. In this application, in addition to SEBS, a compounding agent is also added.

[0016] The surface of the additives is modified to exhibit good compatibility with EVA and SEBS. Simultaneously, the sintered powder consists of zinc oxide whiskers coated with alumina. Compared to spherical calcium carbonate particles and silica particles, zinc oxide whiskers provide more bonding surfaces when the surrounding material undergoes deformation parallel to the whisker direction, thus offering greater recovery force during deformation recovery. The alumina coating on the zinc oxide enhances its strength, and the varying distribution and degree of alumina on the zinc oxide surface improves surface roughness, further strengthening the adhesion between the additives and EVA and SEBS.

[0017] Therefore, by combining SEBS with additives, a multidimensional stress structure network of EVA / SEBS-additive modified whiskers-(EVA / SEBS)n is formed within the sole material. This reduces the amount of permanent compression deformation of the sole material without affecting its shape or increasing its density or hardness, thus improving the feel of the shoe.

[0018] Preferably, the calcined powder is obtained by calcining zinc oxide whiskers coated with aluminum hydroxide gel.

[0019] By adopting the above technical solution, zinc oxide is coated with aluminum hydroxide gel and then converted into aluminum oxide at high temperature. On the one hand, the firing temperature is reduced, thereby reducing the difficulty of obtaining the firing powder. On the other hand, the zinc oxide whiskers and aluminum oxide are more stably bonded, and aluminum oxide plays a reinforcing role on the zinc oxide whiskers. At the same time, the aluminum oxide has more structural pores, which provides stronger bonding force with EVA and SEBS.

[0020] The preferred method for preparing the calcined powder includes the following steps: adding zinc oxide whiskers to a liquid containing soluble aluminum salts, adjusting the pH of the liquid to convert the soluble aluminum salts into aluminum hydroxide precipitate, and drying, calcining, crushing, and sieving the mixture containing zinc oxide whiskers and aluminum hydroxide to obtain calcined powder.

[0021] By adopting the above technical solution, zinc oxide whiskers are first introduced into an aluminum ion environment, and then the aluminum ions are converted into aluminum hydroxide. Aluminum hydroxide is generated directly between zinc oxide whiskers. Aluminum hydroxide makes it easier to coat zinc oxide whiskers, and at the same time, the mixing of zinc oxide whiskers and aluminum hydroxide is more uniform, resulting in better performance of the compounding agent.

[0022] Preferably, the method for preparing the calcined powder includes the following steps:

[0023] After adding zinc oxide whiskers to a liquid containing soluble aluminum salts, a thickener is added to adjust the liquid viscosity to 350-400 cP. Then, the pH of the liquid is adjusted until the soluble aluminum salts are completely converted and the liquid viscosity is not less than 300 cP.

[0024] Preferably, the liquid viscosity before conversion of soluble aluminum salt is adjusted to 380-390 cP, and the liquid viscosity after conversion of soluble aluminum salt is adjusted to 300-330 cP.

[0025] By adopting the above technical solution, zinc oxide whiskers have a high density and are prone to settling to the bottom. To make the liquid and aluminum hydroxide mix evenly, stirring is required. However, under the action of stirring shear force, aluminum hydroxide in the lower layer is prone to self-densification and agglomeration with other solid particles. Some zinc oxide whiskers are not coated with aluminum hydroxide, while other zinc oxide whiskers form large, spherical particles due to excessive coating and agglomeration with aluminum hydroxide, and no longer have the synergistic effect with SEBS.

[0026] In this application, the viscosity of the liquid before the conversion of soluble aluminum salt is adjusted and the viscosity of the liquid after the conversion of soluble aluminum salt is controlled, which prevents zinc oxide whiskers and aluminum hydroxide from settling during the mixing process. At the same time, zinc oxide whiskers and aluminum hydroxide are fully dispersed in the liquid, greatly reducing the generation of agglomerated particles, thereby making the synergistic effect of the obtained compounding agent better.

[0027] Preferably, the thickener is polyacrylamide.

[0028] By adopting the above technical solution, less polyacrylamide is needed to meet the thickening requirements, while also providing better resistance to interference from metal ions.

[0029] Preferably, the compounding agent is obtained by silane modification of n-octyltriethoxysilane.

[0030] By adopting the above technical solution, the synergistic effect of the silane modification additives in the case of n-octyltriethoxysilane is good.

[0031] Secondly, the present invention provides a women's shoe sole, implemented using the following solution:

[0032] A women's shoe sole, comprising a midsole or outsole made from the aforementioned EVA sole material.

[0033] By adopting the above technical solution, the sole of this application combines the original lightweight and softness of EVA soles, and is not easy to flatten or harden after long-term wear, resulting in a good user experience.

[0034] In summary, the present invention has the following beneficial effects:

[0035] 1. This application forms a multidimensional stress structure network of EVA / SEBS-modified whiskers-(EVA / SEBS)n within the sole material, which reduces the amount of permanent compression deformation of the sole material and improves the feel of the shoe without affecting the shaping of the sole material or increasing the density and hardness of the sole.

[0036] 2. In this application, aluminum hydroxide is coated on zinc oxide whiskers in a thickened aqueous environment, and then the additives are obtained through sintering, crushing, and surface modification. The synergistic effect with SEBS is better.

[0037] 3. The sole of this application combines the original lightweight and softness of EVA soles with the ability to withstand long-term wear without flattening or hardening, resulting in a good user experience. Detailed Implementation

[0038] raw material:

[0039] EVA is Yangzi BASF 5110J;

[0040] The HDPE is TAISOX HDPE 9000 from Taiwan, China.

[0041] SEBS is Baling Petrochemical YH-501;

[0042] The foaming agent is azodicarbonamide;

[0043] The filler is calcium carbonate powder with a particle size of 10–50 μm.

[0044] Preparation Example 1

[0045] The additive is a sintered powder with a surface modified by a silane modifier. The sintered powder is zinc oxide whiskers coated with aluminum oxide.

[0046] The preparation method of the compounding agent is as follows:

[0047] T1: Add zinc oxide whiskers with a particle size of 60±10nm to a 0.5mol / L aluminum chloride solution at a dosage of 77g / L to obtain material K1;

[0048] T2: Thickener, which is polyacrylamide, is added to material K1 while stirring. When the viscosity of the material reaches 370-400 cP, material K2 is obtained.

[0049] T3: While stirring, add a pH adjuster (ammonia water) to adjust the pH of the K2 material. After adjusting the pH to 7.2, test the viscosity of the material. If the viscosity of the material is not less than 300 cP, then the K3 material is obtained.

[0050] T3: Dry K3 material to obtain solid matter, calcine the solid matter to constant weight at 1020±10℃ to obtain calcined matter, crush the calcined matter and sieve it to obtain calcined powder at 80±10nm.

[0051] T3: Immerse the calcined powder in a silane modification solution for 2 hours. Here, the silane modification solution is a 3.5 wt% n-octyltriethoxysilane solution. Then, take out the powder, dry it, and sieve it to 80 ± 10 nm as a compounding agent.

[0052] The viscosity of K2 material is sampled and tested during the preparation process. A viscosity of 370-400 cP is considered acceptable. If the viscosity is too low, thickener is added until it is acceptable.

[0053] Preparation Examples 2-16

[0054] The additives used differ from those used in Preparation Example 1 in terms of raw material parameters or process parameters, as shown in Table 1 below.

[0055] Table 1. Partial parameters of preparation examples 1-16

[0056]

[0057]

[0058] Note: The viscosity of K3 material is sampled and tested during the preparation process. If the viscosity is too high, water and pH adjuster can be added to reduce the viscosity while ensuring that the pH is greater than 7.2.

[0059] Preparation Example 17

[0060] The additives are sintered powders with a surface modified by a silane modifier. The sintered powders are zinc oxide whiskers coated with aluminum oxide.

[0061] The preparation method of the compounding agent is as follows:

[0062] Add a pH adjuster (ammonia water) to a 0.5 mol / L aluminum chloride solution to adjust the pH of the material to 7.2.

[0063] Add zinc oxide whiskers with a particle size of 100±10nm to each L of aluminum chloride solution, and stir to mix evenly.

[0064] The filtered material was dried and calcined at 1020±10℃ to constant weight. The solid material was then crushed and sieved to obtain calcined powder with a particle size of 160±10nm.

[0065] The calcined powder was soaked in a 3.5 wt% n-octyltriethoxysilane solution for 2 hours, and then the powder was dried and sieved to 160 ± 10 nm as a compounding agent.

[0066] Preparation Example 18

[0067] The additives are sintered powders with a surface modified by a silane modifier. The sintered powders are zinc oxide whiskers coated with aluminum oxide.

[0068] The preparation method of the compounding agent is as follows:

[0069] Add a pH adjuster (ammonia water) to a 0.5 mol / L aluminum chloride solution to adjust the pH of the material to 7.2.

[0070] Add thickener until the material viscosity is greater than 300 cP. Here, the thickener is polyacrylamide, and the actual adjusted viscosity is 326 cP.

[0071] Add zinc oxide whiskers with a particle size of 100±10nm to each L of aluminum chloride solution, and stir to mix evenly.

[0072] The filtered material was dried and calcined at 1020±10℃ to constant weight. The solid material was then crushed and sieved to obtain calcined powder with a particle size of 160±10nm.

[0073] The calcined powder was soaked in a 3.5 wt% n-octyltriethoxysilane solution for 2 hours, and then the powder was dried and sieved to 160 ± 10 nm as a compounding agent.

[0074] Preparation Example 19

[0075] The additives are sintered powders with a surface modified by a silane modifier. The sintered powders are zinc oxide whiskers coated with aluminum oxide.

[0076] The preparation method of the compounding agent is as follows:

[0077] T1: Add zinc oxide whiskers with a particle size of 100±10nm to a 0.5mol / L aluminum chloride solution at a dosage of 77g / L to obtain material K1;

[0078] T2: While stirring, add a pH adjuster (ammonia water) to adjust the pH of material K1. After adjusting the pH to 7.2, material K3 is obtained.

[0079] T3: Dry K3 material to obtain solid matter, calcine the solid matter at 1020±10℃ to constant weight to obtain calcined matter, crush the calcined matter and sieve it to obtain calcined powder at 160±10nm.

[0080] T3: The calcined powder is soaked in a 3.5wt% n-octyltriethoxysilane solution for 2 hours, and then the powder is dried and sieved to 160±10nm as a compounding agent.

[0081] Comparative Preparation Example 1

[0082] The additives are powder particles whose surface is modified with a silane modifier. The powder particles are prepared by mixing zinc oxide whiskers and nano-alumina powder.

[0083] The preparation method of the additive is as follows: Alumina powder with a particle size of 10±5nm is added to water at a mass ratio of 1:1 and stirred to form a suspension. Zinc oxide whiskers of 100±10nm are added at a mass ratio of aluminum oxide to zinc oxide of 0.6:1. After mixing evenly, the mixture is filtered. The filtered material is dried and calcined at 1020±10℃ to constant weight to obtain the calcined material. The calcined material is crushed and sieved to obtain powder particles of 160±10nm.

[0084] T3: The powder particles are soaked in a 3.5wt% n-octyltriethoxysilane solution for 2 hours, and then the powder is dried and sieved to 160±10nm as a compounding agent.

[0085] Example 1

[0086] A shoe sole material is prepared from the following raw materials in parts by weight:

[0087] 100kg EVA, 12kg HDPE, 2kg foaming agent, 8kg filler, 8kg SEBS; 3kg compounding agents.

[0088] The compounding agent is the compounding agent obtained in Preparation Example 1.

[0089] The method for preparing the sole material in Example 1 is as follows:

[0090] S1: Weigh out EVA, HDPE, filler, SEBS and compounding agents, mix them together and knead them. After melting, add foaming agent and continue mixing at 186±3℃ for 130min.

[0091] S2: Inject the mixed material into a mold to foam, and obtain the shoe sole material.

[0092] Examples 2-19

[0093] A shoe sole material differs from that of Preparation Example 1 in terms of raw material parameters or process parameters. The differences are shown in Table 2 below.

[0094] Table 2. Partial parameter table for Examples 1-19

[0095]

[0096]

[0097] Comparative Example 1

[0098] A shoe sole material is prepared from the following raw materials in parts by weight: 105 kg of EVA, 15 kg of HDPE, 6 kg of foaming agent, 10 kg of filler, and 4.5 kg of compounding agents.

[0099] The foaming agent is azodicarbonamide;

[0100] The filler is calcium carbonate powder with a particle size of 10–50 μm;

[0101] The compounding agent is the compounding agent obtained in Preparation Example 1.

[0102] The method for preparing the sole material in Example 1 is as follows:

[0103] S1: Weigh out the EVA, HDPE, fillers, and compounding agents, mix them together, melt them, add the foaming agent, and continue mixing at 186±3℃ for 130 min.

[0104] S2: Inject the mixed material into a mold to foam, and obtain the shoe sole material.

[0105] Comparative Example 2

[0106] A shoe sole material is prepared from the following raw materials in parts by weight: 105 kg of EVA, 15 kg of HDPE, 6 kg of foaming agent, 10 kg of filler, and 10 kg of SEBS.

[0107] The foaming agent is azodicarbonamide;

[0108] The filler is calcium carbonate powder with a particle size of 10–50 μm.

[0109] The method for preparing the sole material in Example 1 is as follows:

[0110] S1: Weigh out the EVA, HDPE, fillers, and compounding agents, mix them together, melt them, add the foaming agent, and continue mixing at 186±3℃ for 130 min.

[0111] S2: Inject the mixed material into a mold to foam, and obtain the shoe sole material.

[0112] Comparative Example 3

[0113] A shoe sole material is prepared from the following raw materials in parts by weight: 105 kg of EVA, 15 kg of HDPE, 6 kg of foaming agent, and 10 kg of filler.

[0114] The foaming agent is azodicarbonamide;

[0115] The filler is calcium carbonate powder with a particle size of 10–50 μm.

[0116] The method for preparing the sole material in Example 1 is as follows:

[0117] S1: Weigh out the EVA, HDPE and filler, mix them together and knead them. After melting, add the foaming agent and continue mixing at 186±3℃ for 130min.

[0118] S2: Inject the mixed material into a mold to foam, and obtain the shoe sole material.

[0119] Comparative Example 4

[0120] A shoe sole material, which differs from Example 2 in that the additives are derived from Comparative Preparation Example 1.

[0121] The density, hardness (measured according to the method for measuring the hardness of shoe soles in GB / T 3903.4-2017), and permanent compression set (measured according to HGT 2876) of the sole materials obtained in Examples 1-19 and Comparative Examples 1-4 were tested. The test results are shown in Table 3 below.

[0122]

[0123]

[0124] By comparing Examples 1-5 and Comparative Examples 1-3 with Tables 2 and 3, it can be seen that the hardness and density of the sole materials in Examples 1-5 do not change much, but the permanent compression deformation rate is significantly lower than that in Comparative Examples 1-3. In this application, SEBS is added along with a compounding agent. The SEBS and the compounding agent work synergistically to form a multidimensional stress structure network of EVA / SEBS-compounding agent modified whiskers-(EVA / SEBS)n in the sole material. Without affecting the shaping of the sole material or increasing the density and hardness of the sole, the permanent compression deformation of the sole material is reduced, thus improving the feel of the shoe.

[0125] Comparing Examples 2 and 6-10, it can be seen that the viscosity of the aluminum hydroxide solution before and after conversion during the preparation of the compounding agent has an impact on the synergistic effect of the compounding agent.

[0126] Comparing Examples 6-9, it can be seen that the viscosity of aluminum hydroxide before conversion in Example 8 is significantly lower than that in Examples 6 and 7, and its permanent compression set is greater than that in Examples 6 and 7. In Example 9, the viscosity of aluminum hydroxide before conversion is significantly higher than that in Examples 6 and 7, and its permanent compression set is greater than that in Examples 6 and 7. Therefore, the viscosity of aluminum hydroxide before conversion should be controlled at 370-400 cP during the preparation of the compounding agent.

[0127] In Examples 6, 7 and 10, the liquid after aluminum hydroxide conversion was obtained by adding liquid to the liquid before aluminum hydroxide conversion. In the preparation of the compounding agent in Example 10, the viscosity of the liquid after aluminum hydroxide conversion was significantly lower than 300 cP, and its permanent compression set was greater than that in Examples 6 and 7. In the preparation of the compounding agent, the viscosity of the liquid after aluminum hydroxide conversion should be controlled to be not less than 300 cP.

[0128] As can be seen from Examples 6, 7 and 11-14, it is preferable to control the liquid viscosity of aluminum hydroxide before conversion to 380-390 cP and the liquid viscosity of aluminum hydroxide after conversion to 300-330 cP during the preparation of the additives.

[0129] Comparing Examples 2, 15, and 16, it can be seen that the thickener in this application can also be sodium alginate, and the silane modifier used in conjunction with the additives can also be dimethyldimethoxysilane.

[0130] Comparing Examples 2, 17, and 18, it can be seen that the permanent compression set of Examples 17 and 18 is higher than that of Example 2. In this application, zinc oxide is added to the liquid before aluminum ions are converted into aluminum hydroxide, and then aluminum ions are converted into aluminum hydroxide, which can enhance the synergistic effect of the obtained compounding agent and SEBS.

[0131] Comparing Examples 2 and 19, it can be seen that the permanent compression set of Example 19 is higher than that of Example 2. In this application, the aluminum ions are thickened into a liquid before being converted into aluminum hydroxide, and then the aluminum ions are converted into aluminum hydroxide, which can enhance the synergistic effect between the obtained compounding agent and SEBS.

[0132] This specific embodiment is merely an explanation of the present invention and is not intended to limit the invention. After reading this specification, those skilled in the art can make modifications to this embodiment without contributing any inventive step, but such modifications are protected by patent law as long as they are within the scope of the claims of the present invention.

Claims

1. An EVA shoe sole material, characterized in that: It is prepared from the following raw materials in parts by weight: 100-110 parts of EVA; HDPE 12-18 parts; 2-4 parts of foaming agent; 8-12 parts of filler; 8-12 SEBS; Add 3 to 5.5 parts of auxiliary agents; The compounding agent is a calcined powder with a surface modified by n-octyltriethoxysilane. The calcined powder is zinc oxide whiskers coated with alumina. The particle size of the compounding agent is 80-200 nm. The sintered powder is obtained by coating zinc oxide whiskers with aluminum hydroxide gel and then sintering them. Zinc oxide whiskers were added to an aluminum chloride solution to obtain material K1; While stirring K1 material, thickener is added. When the viscosity of the material reaches 380-390 cP, K2 material is obtained. While stirring, pH adjuster was added to adjust the pH of material K2. After the pH was adjusted to 7.2, the viscosity of the material was tested. The viscosity of the material was 300-330 cP, and material K3 was obtained. The K3 material is dried to obtain a solid, which is then calcined, crushed, and sieved to obtain calcined powder.

2. The EVA sole material according to claim 1, characterized in that: The thickener is polyacrylamide.

3. A women's shoe sole, characterized in that, The midsole or outsole is made from the EVA sole material described in any one of claims 1 to 2.

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