Eva foamed sole and preparation method therefor

Abstract

The present invention provides an EVA foamed sole and a preparation method therefor. The EVA foamed sole is prepared from an EVA composite material by means of mixing and foaming processes, and the EVA composite material comprises the following components A and B in parts by weight; the component A comprises: 25-30 parts of EVA 7360; 25-30 parts of EVA 7470; 15-22 parts of EA 40055; 5-10 parts of thermoplastic polyurethane elastomer rubber; 1-2 parts of a foaming agent; 2-3 parts of zinc oxide; 1.0-1.2 parts of zinc stearate; 3-8 parts of a dispersing agent; 0.3-0.5 parts of an active agent; and 0.5-1 part of a lubricant; and the component B comprises: 20-40 parts of a POE complex. The EVA foamed sole has good shock absorption, elasticity, impact strength and compression set rate, has low size shrinkage rate and moderate hardness, and is comfortable to wear.

Description

A kind of EVA foam sole and preparation method thereof Technical Field

[0001] The present invention relates to the technical field of shoe soles, in particular to an EVA shoe sole foaming method. Background Art

[0002] Ethylene-vinyl acetate copolymer (EVA) foam for footwear is the preferred material for most casual and running shoes from renowned domestic and international sports brands. Its lightweight, impact-resistant, and comfortable soles are highly sought after by consumers.

[0003] Chinese invention patent CN202210609152.6 discloses a highly elastic and fold-resistant EVA foamed environmentally friendly sole and a preparation method thereof. The EVA foamed environmentally friendly sole is composed of the following raw materials: EVA, isoprene rubber, recycled rubber powder, foaming agent, cross-linking agent, accelerator, mica powder, sepiolite powder, wollastonite powder, polyoxyethylene fatty alcohol amine, fatty acid diethanolamine, magnesium oxide, and stearic acid. This application stipulates that EVA, isoprene rubber and recycled rubber powder are mixed with each other, and their performance can be complementary, so that the prepared rubber has good elasticity, folding resistance and wear resistance; by introducing mica powder as a filler, it can also be combined with magnesium oxide to improve the bending strength and internal stress of the prepared EVA foamed sole, prevent the EVA foamed sole from cracking due to bending or expansion deformation, and ensure the folding resistance of the prepared EVA foamed sole. This patent utilizes the interaction of diethylenediamine, zinc acetate, and barium stearate to lower the foaming temperature and regulate the decomposition rate of the foaming agent. Combined with the porous structure of sepiolite powder, during foaming, the decomposed gas can be evenly filled into the overall system through the evenly dispersed sepiolite powder, forming a uniform closed-cell structure. The closed-cell structure is independent of each other, and the bubbles are not connected, ensuring good mechanical properties. This patent solves the problem of eliminating the noise generated by gas when the sole is subjected to stress. However, the use of a large amount of recycled rubber powder in the main gas material increases the hardness and weight of the sole, resulting in reduced overall elasticity, increased weight, increased hardness, and reduced wearing comfort.

[0004] Therefore, if air cells could be formed within the sole, not only would the sole's weight be further reduced, but its shock absorption and elasticity would also be enhanced, further improving wearing comfort. There is a need to develop new EVA soles and their preparation methods to address the heavy weight of existing EVA soles while maintaining their excellent properties, such as elasticity, lightness, a moderate hardness, and comfort.

[0005] Summary of the Invention

[0006] In order to overcome the shortcomings of the existing technology, the present invention provides an EVA sole and a preparation method thereof. By adding polyurethane to the EVA main material and controlling the speed and method of foaming, an air bag wrapped in the sole is formed. This not only solves the problem of the existing EVA sole being heavy, but also ensures that the sole is lightweight, elastic, moderately soft and hard, and comfortable to wear.

[0007] The technical solution of the present invention is as follows: an EVA foam sole is prepared by mixing and foaming an EVA composite material, wherein the EVA composite material comprises the following components A and B in parts by weight:

[0008] Component A includes: EVA7360: 25-30 parts; EVA7470: 25-30 parts; EA40055: 15-22 parts; thermoplastic polyurethane elastomer rubber: 5-10 parts; foaming agent: 1-2 parts; zinc oxide: 2-3 parts; zinc stearate: 1.0-1.2 parts; dispersant: 3-8 parts; active agent: 0.3-0.5 parts; lubricant: 0.5-1 parts.

[0009] Component B includes: POE complex.

[0010] The foaming agent is selected from azo compounds, sulfonylhydrazide compounds or carbonate compounds.

[0011] The foaming agent is azodicarbonamide, 4,4-oxodibenzenesulfonylhydrazide or calcium carbonate.

[0012] The dispersant is selected from terminal polyisobutylene and / or naphthenic oil.

[0013] The lubricant comprises: 0.15-0.5 parts of erucamide; and 0.15-0.5 parts of oxidized polyethylene wax powder.

[0014] The POE complex comprises 10-20 parts of Engage8200 (POE) and 10-20 parts of Engage8003 (POE).

[0015] The preparation method of the EVA foam sole comprises the following steps:

[0016] 1) Weighing the components of the A component and the B component according to the formula, mixing and granulating them in sequence to obtain a foaming composite of the A component and a foaming composite of the B component;

[0017] 2) placing the foamed composite of component A in a sole mold to form a sole, wherein a groove is formed on the sole; forming a groove cover of the foamed composite of component A in one mold, wherein the groove cover matches the notch of the groove; and forming the foamed composite of component B in another mold to form a sheet that can be placed in the groove;

[0018] 3) placing the sheet in the groove of the sole, covering it with the groove cover, placing it in a mold, heating it to 170-190° C., reacting it for 15 minutes to foam it, and cooling it to room temperature;

[0019] 4) taking out the sole blank formed in the sole mold and trimming it to obtain the EVA foam sole.

[0020] In the present invention, the EVA7360 is a chloride-ethylene-vinyl acetate copolymer, which is widely used in foaming shoe materials and has a cross-linking foaming effect.

[0021] The EVA7470 and the EA40055 are ethylene vinyl acetate copolymers, which are thermoplastic resins copolymerized by non-polar ethylene monomers and highly polar vinyl acetate monomers. They are random copolymers with a high degree of branching, good softness and elasticity, and resistance to chemical corrosion and impact.

[0022] The Engage 8003 (POE) ethylene-octene copolymer has excellent flow properties and promotes uniform mixing of the components.

[0023] The thermoplastic polyurethane elastomer rubber has excellent wear resistance, and adding a small amount of thermoplastic polyurethane elastomer rubber can improve the wear resistance of the sole.

[0024] The EVA foam sole of the present invention has a slow foaming speed and low foaming efficiency in its component A, which contains a thermoplastic polyurethane elastomer (TPE) and a foaming agent. In contrast, its component B contains a POE complex, which has a fast foaming speed and produces large and numerous bubbles. After foaming is completed in a sole mold, component A encapsulates component B, so that the bubbles formed by component B are all formed inside the sole, forming a closed cavity. Even if the sole is subjected to stress, the gas in the closed cavity cannot be expelled, thereby achieving good elasticity and shock resistance.

[0025] The EVA foam sole of the present invention further comprises thermoplastic polyurethane elastomer rubber in component A, which is formed on the surface of the sole. The thermoplastic polyurethane elastomer rubber imparts good wear resistance to this part of the material, thereby making the sole have good wear resistance and long service life. DETAILED DESCRIPTION

[0026] In order to make the purpose of the invention, technical solutions and technical effects of the present invention more clear, the present invention will be further described below in conjunction with specific embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention.

[0027] Example 1

[0028] An EVA foamed sole is prepared by mixing and foaming an EVA composite material, wherein the EVA composite material comprises the following components A and B in parts by weight:

[0029] Component A includes: EVA7360: 26 parts; EVA7470: 37 parts; EA40055: 22 parts; thermoplastic polyurethane elastomer rubber: 6 parts; foaming agent: 1 part; zinc oxide: 2 parts; zinc stearate: 1.2 parts; dispersant: 5 parts; active agent: 0.4 parts; lubricant: 0.8 parts;

[0030] Component B is a POE complex, including: Engage8200 (POE): 15 parts; Engage8003 (POE): 15 parts.

[0031] The foaming agent is selected from the azo compound azodicarbonamide. The dispersant is selected from terminal polyisobutylene and naphthenic oil. The lubricant includes: 0.5 parts of erucamide and 0.5 parts of oxidized polyethylene wax powder.

[0032] The preparation method of the EVA foam sole comprises the following steps:

[0033] 1) Weighing the components of the A component and the B component according to the formula, mixing and granulating them in sequence to obtain a foaming composite of the A component and a foaming composite of the B component;

[0034] 2) placing the foamed composite of component A in a sole mold to form a sole, wherein a groove is formed on the sole; forming a groove cover of the foamed composite of component A in one mold, wherein the groove cover matches the notch of the groove; and forming the foamed composite of component B in another mold to form a sheet that can be placed in the groove;

[0035] 3) placing the sheet in the groove of the sole, covering it with the groove cover, placing it in a mold, heating it to 170-190° C., reacting it for 15 minutes to foam it, and cooling it to room temperature;

[0036] 4) taking out the sole blank formed in the sole mold and trimming it to obtain the EVA foam sole.

[0037] Example 2

[0038] An EVA foamed sole is prepared by mixing and foaming an EVA composite material, wherein the EVA composite material comprises the following components A and B in parts by weight:

[0039] Component A includes: EVA7360: 25 parts; EVA7470: 25 parts; EA40055: 20 parts; thermoplastic polyurethane elastomer rubber: 8 parts; foaming agent: 1.5 parts; zinc oxide: 3 parts; zinc stearate: 1.0 parts; dispersant: 3 parts; active agent: 0.4 parts; lubricant: 0.5 parts;

[0040] Component B is a POE complex, including: Engage8200 (POE): 10 parts; Engage8003 (POE): 20 parts.

[0041] The foaming agent is selected from azo compounds, namely azodicarbonamide. The dispersant is selected from terminal polyisobutylene. The lubricant includes: 0.5 parts of erucamide and 0.15 parts of oxidized polyethylene wax powder.

[0042] The preparation method of the EVA foam sole comprises the following steps:

[0043] 1) Weighing the components of the A component and the B component according to the formula, mixing and granulating them in sequence to obtain a foaming composite of the A component and a foaming composite of the B component;

[0044] 2) placing the foamed composite of component A in a sole mold to form a sole, wherein a groove is formed on the sole; forming a groove cover of the foamed composite of component A in one mold, wherein the groove cover matches the notch of the groove; and forming the foamed composite of component B in another mold to form a sheet that can be placed in the groove;

[0045] 3) placing the sheet in the groove of the sole, covering it with the groove cover, placing it in a mold, heating it to 170-190° C., reacting it for 15 minutes to foam it, and cooling it to room temperature;

[0046] 4) taking out the sole blank formed in the sole mold and trimming it to obtain the EVA foam sole.

[0047] Example 3

[0048] An EVA foamed sole is prepared by mixing and foaming an EVA composite material, wherein the EVA composite material comprises the following components A and B in parts by weight:

[0049] Component A includes: EVA7360: 30 parts; EVA7470: 30 parts; EA40055: 15 parts; thermoplastic polyurethane elastomer rubber: 5 parts; foaming agent: 2 parts; zinc oxide: 2.5 parts; zinc stearate: 1.2 parts; dispersant: 5 parts; active agent: 0.3 parts; lubricant: 1 part;

[0050] Component B is a POE complex, including: Engage8200 (POE): 20 parts; Engage8003 (POE): 15 parts.

[0051] The foaming agent is selected from sulfonylhydrazide compounds, namely 4,4-oxodiphenylsulfonylhydrazide. The dispersant is naphthenic oil. The lubricant includes: 0.5 parts of erucamide and 0.15 parts of oxidized polyethylene wax powder.

[0052] The preparation method of the EVA foam sole comprises the following steps:

[0053] 1) Weighing the components of the A component and the B component according to the formula, mixing and granulating them in sequence to obtain a foaming composite of the A component and a foaming composite of the B component;

[0054] 2) placing the foamed composite of component A in a sole mold to form a sole, wherein a groove is formed on the sole; forming a groove cover of the foamed composite of component A in one mold, wherein the groove cover matches the notch of the groove; and forming the foamed composite of component B in another mold to form a sheet that can be placed in the groove;

[0055] 3) placing the sheet in the groove of the sole, covering it with the groove cover, placing it in a mold, heating it to 170-190° C., reacting it for 15 minutes to foam it, and cooling it to room temperature;

[0056] 4) taking out the sole blank formed in the sole mold and trimming it to obtain the EVA foam sole.

[0057] Example 4

[0058] An EVA foamed sole is prepared by mixing and foaming an EVA composite material, wherein the EVA composite material comprises the following components A and B in parts by weight:

[0059] Component A includes: EVA7360: 28 parts; EVA7470: 28 parts; EA40055: 22 parts; thermoplastic polyurethane elastomer rubber: 10 parts; foaming agent: 1 part; zinc oxide: 2 parts; zinc stearate: 1.1 parts; dispersant: 8 parts; active agent: 0.5 parts; lubricant: 0.8 parts;

[0060] Component B is a POE complex, including: Engage8200 (POE): 15 parts; Engage8003 (POE): 10 parts.

[0061] The foaming agent is selected from carbonate compounds, namely calcium carbonate. The dispersant is selected from a mixture of terminal polyisobutylene and naphthenic oil. The lubricant includes: 0.3 parts of erucamide and 0.3 parts of oxidized polyethylene wax powder.

[0062] The preparation method of the EVA foam sole comprises the following steps:

[0063] 1) Weighing the components of the A component and the B component according to the formula, mixing and granulating them in sequence to obtain a foaming composite of the A component and a foaming composite of the B component;

[0064] 2) placing the foamed composite of component A in a sole mold to form a sole, wherein a groove is formed on the sole; forming a groove cover of the foamed composite of component A in one mold, wherein the groove cover matches the notch of the groove; and forming the foamed composite of component B in another mold to form a sheet that can be placed in the groove;

[0065] 3) placing the sheet in the groove of the sole, covering it with the groove cover, placing it in a mold, heating it to 170-190° C., reacting it for 15 minutes to foam it, and cooling it to room temperature;

[0066] 4) taking out the sole blank formed in the sole mold and trimming it to obtain the EVA foam sole.

[0067] The difference between Comparative Example 1 and Example 1 is that component A does not contain thermoplastic polyurethane elastomer rubber and foaming agent.

[0068] The difference between Comparative Example 2 and Example 2 is that component A does not contain thermoplastic polyurethane elastomer rubber and foaming agent.

[0069] The difference between Comparative Example 3 and Example 3 is that component A does not contain thermoplastic polyurethane elastomer rubber and foaming agent.

[0070] The difference between Comparative Example 4 and Example 4 is that component A does not contain thermoplastic polyurethane elastomer rubber and foaming agent.

[0071] The EVA foam soles prepared in Examples 1-4 and the EVA foam soles prepared in Comparative Examples 1-4 were tested. Impact rebound was tested using a GT-7042-RE impact elasticity testing machine; dimensional shrinkage was measured according to ISO 20873:2001; and compression deformation was measured according to HG / T2876 (temperature 50°C, time 6 hours, compression ratio 50%). The following data were obtained, as shown in Table 1:

[0072] Table 1 Test data of Examples 1-4 and Comparative Examples 1-4

[0073] The above analysis shows that adding thermoplastic polyurethane elastomer rubber to component A can improve the impact strength and compression set of the sole, reduce dimensional shrinkage, and add a foaming agent to increase the foaming ratio. The EVA foam sole prepared by the present invention has good elasticity, moderate hardness, and is comfortable to wear.

[0074] The above is a further detailed description of the present invention in conjunction with specific preferred embodiments, and the specific implementation of the present invention should not be considered to be limited to these descriptions. For those skilled in the art of the present invention, without departing from the concept of the present invention, its architecture can be flexible and varied, and a series of products can be derived. Simply making a few simple deductions or substitutions should be considered to fall within the scope of patent protection of the present invention as determined by the submitted claims.

Claims

1. An EVA foamed sole is made from an EVA composite material through mixing and foaming processes. It is characterized in that The EVA composite material comprises the following components A and B in parts by weight: Component A includes: EVA7360: 25-30 parts; EVA7470: 25-30 parts; EA40055: 15-22 parts; thermoplastic polyurethane elastomer rubber: 5-10 parts; foaming agent: 1-2 parts; zinc oxide: 2-3 parts; zinc stearate: 1.0-1.2 parts; dispersant: 3-8 parts; active agent: 0.3-0.5 parts; lubricant: 0.5-1 parts Component B includes: 20-40 parts of POE compound.

2. The EVA foam sole according to claim 1, It is characterized in that The foaming agent is selected from azo compounds, sulfonyl hydrazide compounds or carbonate compounds.

3. The EVA foam sole according to claim 1 or 2, It is characterized in that The foaming agent is azodicarbonamide, 4,4-oxodibenzenesulfonylhydrazide or calcium carbonate.

4. The EVA foam sole according to claim 1, It is characterized in that The dispersant is selected from terminal polyisobutylene and / or naphthenic oil.

5. The EVA foam sole according to claim 1, It is characterized in that The lubricant comprises: 0.15-0.5 parts of erucamide; and 0.15-0.5 parts of oxidized polyethylene wax powder.

6. The EVA foam sole according to claim 1, It is characterized in that Engage8200(POE):10-20 copies; Engage8003(POE):10-20 copies.

7. The method for preparing the EVA foamed sole according to any one of claims 1 to 6, It is characterized in that The steps include: 1) Weighing the components of the A component and the B component according to the formula, mixing and granulating in sequence to obtain a foaming composite of the A component and a foaming composite of the B component; 2) placing the foamed composite of component A in a sole mold to form a sole, and forming a groove on the sole; forming a groove cover of the foamed composite of component A in one mold, wherein the groove cover matches the groove opening of the groove; and forming the foamed composite of component B in another mold to form a sheet that can be placed in the groove; 3) placing the sheet in the groove of the sole, covering it with the groove cover, placing it in a mold, heating it to 170-190° C., reacting for 15 minutes to foam, and cooling it to room temperature; 4) taking out the raw sole formed in the sole mold and trimming it to obtain the EVA foamed sole.

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