Antiskid foamed shoe sole material and its preparation method

Abstract

The application relates to the field of polymer foaming materials, and particularly discloses an antiskid foaming shoe sole material and a preparation method thereof. The antiskid foaming shoe sole material comprises the following raw materials in parts by weight: ethylene-vinyl acetate copolymer 40-60 parts, foaming agent 1-3 parts, crosslinking agent 1-3 parts, butyronitrile rubber 10-20 parts, glass fiber 1-3 parts, nano silicon dioxide 0.5-1 part, coupling agent 0.3-0.5 part, and the content of vinyl acetate in the ethylene-vinyl acetate copolymer is 20-30%. The antiskid foaming shoe sole material disclosed by the application improves the friction between the shoe sole material and the ground by adding glass fiber and nano silicon dioxide, so that the shoe sole material has excellent antiskid performance.

Description

Technical Field

[0001] This application relates to the field of polymer foam materials, specifically to an anti-slip foam shoe sole material and its preparation method. Background Technology

[0002] Ethylene-vinyl acetate copolymer (EVA) material is used in shoe soles because it has good softness and elasticity, as well as good chemical stability. Therefore, EVA soles are widely used in the soles and lining materials of shoes such as hiking shoes and mountaineering shoes.

[0003] Foaming EVA material can make shoe soles lighter, and the elastic EVA sole material provides some cushioning. However, after foaming, the physical properties of EVA material are significantly reduced, its dimensional stability is poor, and it is prone to deformation, resulting in poor anti-slip performance and a severely shortened lifespan of the sole. Summary of the Invention

[0004] To improve the anti-slip performance of foamed EVA material shoe soles, this application provides an anti-slip foamed shoe sole material and its preparation method.

[0005] In a first aspect, this application provides an anti-slip foamed shoe sole material, which adopts the following technical solution:

[0006] A non-slip foamed shoe sole material comprises the following raw materials in parts by weight: 40-60 parts of ethylene-vinyl acetate copolymer, 1-3 parts of foaming agent, 1-3 parts of crosslinking agent, 10-20 parts of nitrile rubber, 1-3 parts of glass fiber, 0.5-1 parts of nano-silica, and 0.3-0.5 parts of coupling agent, wherein the vinyl acetate content in the ethylene-vinyl acetate copolymer is 20-30%.

[0007] By adopting the above technical solution, nitrile rubber and ethylene-vinyl acetate copolymer are compounded as the base material for shoe soles. Nitrile rubber can improve the wear resistance and waterproof performance of shoe soles, while glass fiber can improve the roughness, tensile strength and elongation at break of shoe soles, and increase the friction between shoe soles and the ground, thus making the prepared shoe soles slip-resistant and wear-resistant.

[0008] Nano-silica can increase the roughness of shoe sole materials, enhancing the friction between the manufactured sole and the ground, and improving the anti-slip performance of the sole. Simultaneously, nano-silica has a large specific surface area, allowing it to fully contact the polymer matrix in the shoe sole material system, uniformly improving the anti-slip performance of the sole material. The surface of nano-silica also possesses certain micropores, which can load and activate foaming agents, improving the dispersion of the foaming agent in the shoe sole material system and forming uniform and stable cells, thus improving foaming efficiency. Coupling agents can promote better integration of nano-silica and glass fiber with other components, increasing the degree of cross-linking between the components of the shoe sole material system, thereby improving the strength and anti-slip performance of the shoe sole product.

[0009] Controlling the vinyl acetate content in the ethylene-vinyl acetate copolymer within a suitable range promotes appropriate elasticity and tensile strength in the ethylene-vinyl acetate copolymer matrix. If the vinyl acetate content in the ethylene-vinyl acetate copolymer is too low, the elasticity and flexibility of the prepared shoe sole material will decrease, resulting in the shoe sole product becoming harder and the friction between the shoe sole material and the ground will decrease, further affecting the wear resistance and anti-slip performance of the shoe sole product.

[0010] Preferably, the foaming agent is azodicarbonamide masterbatch.

[0011] By adopting the above technical solution, azodicarbonamide masterbatch has better dispersibility in the sole material system than conventional foaming agent powder. The azodicarbonamide masterbatch forms fine and uniform cells in the sole material system, and has a closed-cell structure. When the sole product is subjected to external impact, the gas in the cells will expand and restore the sole deformation. Azodicarbonamide masterbatch can improve the elasticity and tear strength of the sole material.

[0012] Preferably, the azodicarbonamide masterbatch raw material comprises the following parts by weight: 20-30 parts azodicarbonamide, 15-20 parts ethylene-vinyl acetate copolymer, and 0.5-1 parts polyethylene glycol.

[0013] By employing the above-mentioned technical solution, the azodicarbonamide masterbatch prepared using ethylene-vinyl acetate copolymer as the matrix can improve the compatibility of azodicarbonamide foaming agent in the shoe sole material system. Polyethylene glycol can enhance the dispersibility of azodicarbonamide in the ethylene-vinyl acetate copolymer matrix, further promoting uniform and stable foaming of the shoe sole material, resulting in better elasticity and deformation resistance in the shoe sole product. Simultaneously, polyethylene glycol can react with the silanol groups on the surface of nano-silica in the shoe sole material system, improving the compatibility and dispersibility of nano-silica in the shoe sole material, further enhancing the anti-slip performance and uniformity of the shoe sole product.

[0014] Preferably, the sole material further includes 0.5-2 parts of β-cyclodextrin.

[0015] By adopting the above technical solution, β-cyclodextrin added to the sole material system can better combine with the sole material system matrix, increase the viscosity of the sole material system, and promote the sole products to have better tensile strength and impact resistance.

[0016] β-Cyclodextrin can act as a nucleating agent, increasing the foaming nucleation rate of shoe sole materials. Simultaneously, it can inhibit excessive cell growth and deformation, forming a stable and uniform cell structure within the sole material, maintaining its good elasticity and toughness. β-Cyclodextrin also has the ability to mask odors, effectively masking the ammonia smell released during the foaming process of azodicarbonamide foaming agents, thus improving the texture of shoe sole materials.

[0017] Preferably, the raw material for the sole also includes 0.3-0.5 parts of zinc stearate.

[0018] By adopting the above technical solution, zinc stearate can reduce the decomposition temperature of the foaming agent, improve the foaming efficiency of the foaming agent in the shoe sole material system, and enable the manufactured insole material to have both flexibility and strength.

[0019] Preferably, the glass fiber has a length of 4-8 mm.

[0020] By adopting the above technical solutions, controlling the length of glass fiber within a suitable range is more conducive to improving the tensile strength, wear resistance and anti-slip performance of shoe sole materials. If the glass fiber length is too large, the glass fiber itself is prone to curling, which affects the compatibility between the glass fiber and the components, and will reduce the strength and wear resistance of the shoe sole products.

[0021] Secondly, this application provides a method for preparing an anti-slip foamed shoe sole material, which adopts the following technical solution: A method for preparing an anti-slip foamed shoe sole material includes the following specific steps:

[0022] Ethylene-vinyl acetate copolymer, nitrile rubber, glass fiber, silica and coupling agent are mixed and kneaded to obtain a mixture. Then, foaming agent and crosslinking agent are added to the mixture and kneaded again. The mixture is then sheeted and foamed to obtain the anti-slip foamed shoe sole material.

[0023] Preferably, the foaming temperature is 150-160℃.

[0024] By adopting the above technical solution, the prepared shoe sole material has certain wear resistance and anti-slip properties, while the ethylene-vinyl acetate copolymer material has good flexibility and elasticity after foaming.

[0025] In summary, this application has the following beneficial effects:

[0026] 1. Because this application uses ethylene-vinyl acetate copolymer and nitrile rubber as the matrix, and then adds glass fiber and nano silica, the roughness of the sole material is improved, which makes the sole material have excellent wear resistance and slip resistance.

[0027] 2. In this application, the azodicarbonamide foaming agent masterbatch prepared using ethylene-vinyl acetate copolymer as the matrix is ​​preferred, which promotes better compatibility of the azodicarbonamide foaming agent masterbatch in the shoe sole material system, reduces the agglomeration of traditional azodicarbonamide powder, improves the foaming efficiency of the foaming agent, and promotes better flexibility and elasticity of the shoe sole material. Detailed Implementation

[0028] The present application will be further described in detail below with reference to the embodiments.

[0029] The average particle size of nano-silica is 60 nm.

[0030] The molecular weight of polyethylene glycol is 800.

[0031] Example of preparation of azodicarbonamide masterbatch

[0032] Preparation Example 1

[0033] The azodicarbonamide masterbatch comprises the following raw materials in parts by weight: 25 kg of azodicarbonamide powder, 18 kg of ethylene-vinyl acetate copolymer, and 0.8 kg of polyethylene glycol, wherein the vinyl acetate content in the ethylene-vinyl acetate copolymer is 15%.

[0034] The preparation method of azodicarbonamide masterbatch includes the following specific steps:

[0035] Azodicarbonamide powder, ethylene-vinyl acetate copolymer and polyethylene glycol were mixed and melt-mixed at 90°C for 20 min, and then extruded and granulated to obtain azodicarbonamide masterbatch with an average diameter of 3 mm × 3 mm.

[0036] Preparation Examples 2-3

[0037] The difference between Preparation Example 2-3 and Preparation Example 1 is that the content of each component in the azodicarbonamide masterbatch raw material is different, as shown in Table 1.

[0038] Table 1: Content of each component in preparation examples 1-3

[0039]

[0040] Preparation Example 4

[0041] The difference between Preparation Example 4 and Preparation Example 1 is that polyethylene glycol is not used in the azodicarbonamide masterbatch raw material.

[0042] Example

[0043] Example 1

[0044] This embodiment provides an anti-slip foam insole material, comprising the following raw materials in parts by weight:

[0045] The product composition includes 50 kg of ethylene-vinyl acetate copolymer, 2 kg of foaming agent, 2 kg of crosslinking agent, 15 kg of nitrile rubber, 2 kg of glass fiber, 0.8 kg of nano-silica, and 0.4 kg of coupling agent. The vinyl acetate content in the ethylene-vinyl acetate copolymer is 25%. The foaming agent is DN4 type ADC foaming agent purchased from Baoneng Chemical Co., Ltd., the crosslinking agent is bis-tert-butylperoxyisopropylbenzene, the glass fiber length is 6 mm, and the coupling agent is silane coupling agent KH550.

[0046] The preparation method of anti-slip foam insole material includes the following specific steps:

[0047] Ethylene-vinyl acetate copolymer and nitrile rubber are mixed and kneaded at 105°C for 15 minutes. Then, glass fiber, coupling agent and nano silica are added and kneaded for another 10 minutes to form a mixture. Then, foaming agent and crosslinking agent are added to the mixture and kneaded for another 20 minutes. Then, the mixture is pressed into sheets to form foam sheets. Finally, the foam sheets are vulcanized and foamed at 155°C to obtain anti-slip foam shoe sole material.

[0048] Example 2

[0049] The difference between Example 2 and Example 1 is that the amount of ethylene-vinyl acetate copolymer used in the anti-slip foamed shoe sole material is 40kg, the amount of foaming agent is 1kg, the amount of crosslinking agent is 3kg, the amount of nitrile rubber is 20kg, the amount of glass fiber is 3kg, the amount of nano silica is 0.5kg, the amount of coupling agent is 0.5kg, and the length of glass fiber is 4mm.

[0050] Example 3

[0051] The difference between Example 3 and Example 1 is that the amount of ethylene-vinyl acetate copolymer used in the anti-slip foamed shoe sole material is 60kg, the amount of foaming agent is 3kg, the amount of crosslinking agent is 1kg, the amount of nitrile rubber is 10kg, the amount of glass fiber is 1kg, the amount of nano silica is 1kg, and the amount of coupling agent is 0.3kg, wherein the length of glass fiber is 8mm.

[0052] Example 4

[0053] The difference between Example 4 and Example 1 is that the vinyl acetate content in the ethylene-vinyl acetate copolymer in the anti-slip foam sole material is 20%.

[0054] Example 5

[0055] The difference between Example 5 and Example 1 is that the vinyl acetate content in the ethylene-vinyl acetate copolymer in the anti-slip foam sole material is 30%.

[0056] Example 6

[0057] The difference between Example 6 and Example 1 is that the glass fiber length in the anti-slip foam sole material is 11mm.

[0058] Example 7

[0059] The difference between Example 7 and Example 1 is that the foaming agent in the raw material of the anti-slip foamed shoe sole is azodicarbonamide masterbatch.

[0060] Example 8

[0061] The difference between Example 8 and Example 1 is that the foaming agent used in the raw material of the anti-slip foamed shoe sole material is derived from Preparation Example 1.

[0062] Example 9

[0063] The difference between Example 9 and Example 1 is that the foaming agent used in the raw material of the anti-slip foamed shoe sole material is derived from Preparation Example 2.

[0064] Example 10

[0065] The difference between Example 10 and Example 1 is that the foaming agent used in the raw material of the anti-slip foamed shoe sole material is derived from Preparation Example 3.

[0066] Example 11

[0067] The difference between Example 11 and Example 1 is that the foaming agent used in the raw material of the anti-slip foamed shoe sole material is derived from Preparation Example 4.

[0068] Example 12

[0069] The difference between Example 12 and Example 8 is that the anti-slip foam sole material also includes 0.4 kg of zinc stearate.

[0070] The preparation method of anti-slip foam insole material includes the following specific steps:

[0071] Ethylene-vinyl acetate copolymer and nitrile rubber are mixed and kneaded at 105°C for 15 minutes. Then, glass fiber, zinc stearate, coupling agent and nano silica are added and kneaded for another 10 minutes to form a mixture. Then, foaming agent and crosslinking agent are added to the mixture and kneaded for another 20 minutes. Then, the mixture is pressed into sheets to form foam sheets. Finally, the foam sheets are vulcanized and foamed at 155°C to obtain anti-slip foam shoe sole material.

[0072] Example 13

[0073] The difference between Example 13 and Example 12 is that the amount of zinc stearate used in the anti-slip foam sole material is 0.3 kg.

[0074] Example 14

[0075] The difference between Example 14 and Example 12 is that the amount of zinc stearate used in the anti-slip foam sole material is 0.3 kg.

[0076] Example 15

[0077] The difference between Example 15 and Example 12 is that the anti-slip foamed shoe sole material also includes 1.3 kg of β-cyclodextrin.

[0078] The preparation method of anti-slip foam insole material includes the following specific steps:

[0079] Ethylene-vinyl acetate copolymer and nitrile rubber were mixed and stirred at 105°C for 15 minutes. Then, glass fiber, zinc stearate, coupling agent and nano silica were added and stirred for another 10 minutes to form a mixture. Then, foaming agent, β-cyclodextrin and crosslinking agent were added to the mixture and stirred for another 20 minutes. Then, the mixture was pressed into sheets to form foam sheets. Finally, the foam sheets were vulcanized and foamed at 155°C to obtain anti-slip foam shoe sole material.

[0080] Example 16

[0081] The difference between Example 16 and Example 15 is that the amount of β-cyclodextrin used in the raw material of the anti-slip foam shoe sole is 0.5 kg.

[0082] Example 17

[0083] The difference between Example 17 and Example 15 is that the amount of β-cyclodextrin used in the raw material of the anti-slip foam shoe sole is 2 kg.

[0084] Comparative Example

[0085] Comparative Example 1

[0086] The difference between Comparative Example 1 and Example 1 is that nitrile rubber is not used in the raw materials of the anti-slip foam sole material.

[0087] Comparative Example 2

[0088] The difference between Comparative Example 2 and Example 1 is that nano-silica is not used in the raw materials of the anti-slip foam sole material.

[0089] Comparative Example 3

[0090] The difference between Comparative Example 3 and Example 1 is that the anti-slip foam sole material does not use nano-silica and glass fiber.

[0091] Comparative Example 4

[0092] The difference between Comparative Example 4 and Example 1 is that the vinyl acetate content in the ethylene-vinyl acetate copolymer in the anti-slip foam sole material is 16%.

[0093] Performance testing

[0094] The anti-slip foamed shoe sole materials provided in Examples 1-17 and Comparative Examples 1-4 of this application were subjected to the following performance tests, and the specific test results are shown in Table 2.

[0095] Detection methods

[0096] I. Anti-slip performance

[0097] Referring to GB / T3903.6 "Test Methods for Slip Resistance of Whole Footwear", the static and dynamic friction coefficients of the sole material prepared in this application were determined, with the test interface being the ceramic tile interface.

[0098] II. Mechanical Properties

[0099] Referring to the standard GB / T17200—2008 "Technical Specification for Rubber and Plastic Tensile, Compression and Bending Testing Machine (Constant Speed ​​Drive)", the tensile strength and tear strength of the anti-slip foam shoe sole material prepared in this application were tested under the conditions of room temperature and tensile rate of 500 mm / min.

[0100] III. Elastic Properties

[0101] The elasticity of the anti-slip foamed shoe sole material prepared in this application was tested in accordance with the standard GB / T-10652-2001 "Determination of elasticity of porous polymer elastic materials".

[0102] Table 2: Performance Test Data Table

[0103]

[0104]

[0105] The performance test results show that the anti-slip foamed shoe sole material prepared in this application maintains excellent elasticity while also possessing good anti-slip performance. The usage amounts of each component varied in Examples 1-3, with Example 1 exhibiting the best overall performance. A comparison of the performance test results of Examples 4, 5, and Example 1 reveals that excessively high vinyl acetate content in the ethylene-vinyl acetate copolymer can lead to a decrease in the strength, wear resistance, and anti-slip ability of the shoe sole material. Conversely, excessively low vinyl acetate content can reduce the elasticity and flexibility of the shoe sole material system, resulting in harder shoe soles and reduced friction between the shoe sole and the ground, further affecting the anti-slip performance of the shoe sole. Therefore, Example 1 demonstrates superior overall performance.

[0106] A comparison of the performance of Example 6 and Example 1 shows that when the glass fiber length used in Example 6 is too large, the degree of cross-linking of the sole material system will also be affected. The glass fiber is prone to curling in the ethylene-vinyl acetate copolymer matrix, which ultimately affects the anti-slip performance and strength of the sole material.

[0107] The performance test results of Examples 7 and 1 show that the azodicarbonamide masterbatch used in Example 7 has better overall performance than the conventional azodicarbonamide powder used in Example 1. This further illustrates that the azodicarbonamide masterbatch-type foaming agent can be more uniformly dispersed in the shoe sole material system, resulting in better foaming efficiency of the shoe sole material product.

[0108] A comparison of the performance test results of Examples 8-11 and Example 7 shows that the sole material prepared in Example 8 has superior performance. This is because Example 8 uses azodicarbonamide masterbatch prepared with ethylene-vinyl acetate copolymer as the matrix, which is more compatible with the sole material system, thereby promoting better foaming efficiency of the foaming agent and improving the elasticity and toughness of the sole material. In contrast, Example 11 does not use polyethylene glycol, resulting in decreased dispersibility of the components in the azodicarbonamide masterbatch raw material system. Furthermore, the dispersion effect of polyethylene glycol on nano-silica and glass fibers in the sole material system is also reduced, further affecting the anti-slip performance and foaming effect of the sole material.

[0109] In Examples 12-14, adding different amounts of zinc stearate to the sole material system resulted in sole materials with better anti-slip properties and foaming effects. This is because zinc stearate can lower the foaming temperature of the foaming agent, increase its foaming efficiency, and promote good flexibility in the sole materials. Simultaneously, zinc stearate also acts as a dispersant and lubricant in the sole material system, further promoting the uniform dispersion of nano-silica and glass fibers in the ethylene-vinyl acetate copolymer matrix, thereby further improving the anti-slip properties and strength of the sole materials.

[0110] In Examples 15-17, adding different amounts of β-cyclodextrin to the sole material system further improved the tensile strength and elasticity of the prepared sole materials, further demonstrating that β-cyclodextrin has a significant promoting effect on the foaming effect and strength of the sole material system. Furthermore, in practical use, it was also found that β-cyclodextrin can mask the ammonia odor released during foaming, thus having a masking effect on unpleasant smells.

[0111] A comparison of the performance test results of Comparative Example 1 and Example 1 shows that the tear strength and anti-slip performance of the shoe sole material prepared in Comparative Example 1 are significantly reduced when nitrile rubber is not used, further indicating that the shoe sole material product prepared by compounding nitrile rubber and ethylene-vinyl acetate copolymer has better strength and anti-slip performance.

[0112] Comparing the performance test results of Comparative Examples 2-3 and Example 1, it can be seen that the anti-slip performance of the prepared shoe sole materials decreased even though neither nano-silica was used in Comparative Example 2 nor glass fiber and nano-silica were used in Comparative Example 3. This further illustrates that both glass fiber and nano-silica affect the friction between the shoe sole material and the ground. At the same time, nano-silica also acts as a nucleating agent and can improve the foaming effect of the foaming agent.

[0113] A comparison of the performance test results of Comparative Example 4 and Example 1 shows that the vinyl acetate content in the ethylene-vinyl acetate copolymer used in Comparative Example 4 is too low. The anti-slip performance, strength and elasticity of the prepared shoe sole material will decrease. This further illustrates that an excessively low vinyl acetate content in the ethylene-vinyl acetate copolymer can easily make the shoe sole material too hard, resulting in a decrease in the friction between the shoe sole material and the ground, thereby affecting the protective performance and elasticity of the shoe sole material.

[0114] This specific embodiment is merely an explanation of this application and is not intended to limit it. 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 fall within the scope of the claims of this application.

Claims

1. A non-slip foamed shoe sole material, characterized in that, The raw materials include the following parts by weight: 40-60 parts of ethylene-vinyl acetate copolymer, 1-3 parts of foaming agent, 1-3 parts of crosslinking agent, 10-20 parts of nitrile rubber, 1-3 parts of glass fiber, 0.5-1 part of nano-silica, 0.3-0.5 parts of coupling agent, and 0.5-2 parts of β-cyclodextrin, wherein the vinyl acetate content in the ethylene-vinyl acetate copolymer is 20-30%; The foaming agent is azodicarbonamide masterbatch, and the raw materials of the azodicarbonamide masterbatch include the following parts by weight: 20-30 parts of azodicarbonamide powder, 15-20 parts of ethylene-vinyl acetate copolymer, and 0.5-1 parts of polyethylene glycol.

2. The anti-slip foamed shoe sole material according to claim 1, characterized in that: The raw materials for the sole material also include 0.3-0.5 parts of zinc stearate.

3. The anti-slip foamed shoe sole material according to claim 1, characterized in that: The glass fiber has a length of 4-8 mm.

4. A method for preparing an anti-slip foamed shoe sole material as described in any one of claims 1-3, characterized in that: The specific steps include the following: Ethylene-vinyl acetate copolymer, nitrile rubber, glass fiber, silica and coupling agent are mixed and kneaded to obtain a mixture. Then, foaming agent and crosslinking agent are added to the mixture and kneaded again. The mixture is then sheeted and foamed to obtain the anti-slip foamed shoe sole material.

5. The method for preparing the anti-slip foamed shoe sole material according to claim 4, characterized in that: The foaming temperature is 150-160℃.

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