A method for preparing thermosetting midsole using foamed particles and its application

Abstract

The present application relates to a method for preparing a thermosetting midsole using foamed particles, the method comprising: fusing the foamed particles having graphene oxide on the surface with each other in a midsole mold under the condition of steam heating to form the thermosetting midsole, wherein the body of the foamed particles having graphene oxide on the surface is formed by mixing 60wt% to 95wt% of thermoplastic polyurethane and 5wt% to 40wt% of thermosetting polymer and foaming under non-curing conditions. The thermosetting midsole has high mechanical strength, good thermal stability, good chemical corrosion resistance, good air permeability, and is suitable for outdoor use and extreme environments. The graphene oxide on the surface of the foamed particles prevents the foamed particles from fusing with other foamed particles where the graphene is present, thus naturally leaving a breathable channel. The breathable channel improves the breathability of the shoe and improves the comfort of wearing.

Description

Technical Field

[0001] The present invention relates to a method for preparing a thermosetting midsole and a thermosetting midsole prepared by the method, and in particular to a method for preparing a thermosetting midsole with improved air permeability, wherein the thermosetting midsole optionally has an integrated molding visual effect. Background Art

[0002] The appearance of the popcorn sole is formed by thousands of "popcorns" arranged closely together. The full name of this sole material is polyurethane thermoplastic elastomer, also known as ETPU sole. Its production principle is to increase the volume of the original 0.5mm particle by about 10 times by subjecting each TPU particle to high temperature and pressure, forming elliptical non-cross-linked foamed particles ETPU containing micro-closed bubbles, which are named after their "popcorn" shape. These elliptical non-cross-linked foamed particles with micro-closed bubbles are closely arranged, forming the unique appearance and structure of the popcorn sole.

[0003] Supercritical foaming molding technology has been widely used in shoe materials. This process has gradually become a "black technology" force in the field of shoe materials and is slowly being introduced to the market. TPU shoe materials using supercritical foaming technology have become one of the most high-end shoe materials.

[0004] However, although TPU soles have good tear strength and elasticity, their breathability is relatively poor, which may cause damp, stuffy feet, smelly feet, and even athlete's foot.

[0005] Various soles with ventilation holes are designed in the prior art. However, the strength of the soles will be damaged to a certain extent, and the wearer's sole may feel the ventilation holes of the soles, thereby affecting the wearing comfort.

[0006] Moreover, in the manufacturing process of TPU soles, ventilation holes can generally only be pre-fabricated during the molding process, and it is best not to make ventilation holes after the soles are molded. This is because the manufacture of these ventilation holes will damage the structure of the popcorn unit and affect the strength of the popcorn around the ventilation holes. This is because the epidermis of the popcorn unit usually has the highest strength, and the bubbles inside it are protected by the epidermis. When the epidermis is damaged, the strength around the ventilation holes will deteriorate.

[0007] There is no technology in the prior art that is both breathable and can maintain the good tear strength and elasticity of the existing TPU shoe materials.

[0008] In addition, popcorn soles in the prior art are all made of thermoplastic materials. However, thermoplastic materials have poor thermal stability, support performance and chemical corrosion resistance, and are not suitable for use in occasions that require high thermal stability, chemical corrosion resistance and support performance, such as outdoor sports scenes with extreme conditions. Summary of the invention

[0009] In view of this, the present invention provides a method for preparing a thermosetting midsole using foamed particles. The thermosetting midsole prepared by the method has good air permeability, while still retaining the good tear strength and elasticity of the popcorn midsole shoe material in the prior art, and has good thermal stability, chemical corrosion resistance and support performance.

[0010] Specifically, the present invention provides a method for preparing a thermosetting midsole using foamed particles having graphene oxide on the surface, the method comprising: fusing the foamed particles having graphene oxide on the surface with each other in a midsole mold under the condition of heating with water vapor to form the thermosetting midsole, wherein the body of the foamed particles having graphene oxide on the surface is formed by mixing 60wt% to 95wt% of thermoplastic polyurethane of the body of the foamed particles and 5wt% to 40wt% of thermosetting polymer of the body of the foamed particles and foaming under non-curing conditions.

[0011] Among the foamed particles with graphene oxide on the surface, 5wt% to 40wt% are thermosetting. Thermoplastic polymers are easier to process and reuse, but their thermal stability is poor; while thermosetting polymers are more difficult to process, but have good thermal stability and chemical corrosion resistance. The thermosetting midsole prepared in Implementation 1 has high mechanical strength, good thermal stability, good chemical corrosion resistance, good air permeability, and is suitable for outdoor and extreme environments. Thermosetting midsole has better support performance. In the production of various outdoor shoe materials requiring high support performance, the midsole is required to have higher support performance. The midsole of the present application is particularly suitable for such application scenarios. During the high-temperature fusion process of the graphene oxide on the surface of the foamed particles, the graphene oxide itself also forms a stable chemical bond with the reactive groups on the surface of the foamed particles. The graphene has a multi-layer structure so that the foamed particles where there is graphene cannot be fused with other foamed particles, so a breathable channel is naturally left. Figure 1 This is a schematic diagram of the theoretical ventilation channel.

[0012] In this application, the hydrophilic hydroxyl groups of graphene oxide can react with the reactive groups on polyurethane to form a stable link, while the hydrophobic structure on the other side prevents the foamed particles from merging in some areas, thus leaving a naturally formed air permeable channel on the formed midsole. The channel is mainly formed by graphene. It can not only increase the air permeability of the midsole, but also use the powerful adsorption performance of graphene to achieve deodorization of the sole.

[0013] Furthermore, in the method for preparing a thermosetting midsole using foamed particles having graphene oxide on the surface, the amount of the graphene oxide is 0.05wt% to 2wt% of the body of the foamed particles.

[0014] Since the amount of graphene oxide added is very small, it does not affect the bonding strength between the foamed particles. At the same time, some breathable channels left behind can greatly increase the breathability of the midsole.

[0015] Further, the method for preparing a thermosetting midsole using foamed particles having graphene oxide on the surface, wherein the foamed particles having graphene oxide on the surface are prepared as follows: a mixture of 60wt% to 95wt% of thermoplastic polyurethane and 5wt% to 40wt% of a thermosetting polymer is foamed under non-curing conditions to form a foamed particle body, based on the total weight of the foamed particle body; a suspension of graphene oxide is contacted with the foamed particle body to obtain foamed particles having graphene oxide on the surface.

[0016] Graphene oxide is physically combined with foaming particles in the form of a suspension, and a strong chemical bond is formed during the secondary foaming process.

[0017] Furthermore, the method for preparing a thermosetting midsole using foamed particles having graphene oxide on the surface, wherein the foamed particles having graphene oxide on the surface are prepared as follows: 60wt% to 95wt% of thermoplastic polyurethane and 5wt% to 40wt% of thermosetting polymer are mixed to form a mixture matrix in a molten state; the mixture matrix in a molten state is fully mixed with a foaming agent in a supercritical state (such as carbon dioxide or nitrogen or other gases) to form a single-phase mixed sol;

[0018] The single-phase mixed sol is passed through an extrusion die and enters a normal pressure state, so that a large number of bubble nuclei are precipitated from the foaming agent and expand to obtain hot foaming particles, and powdered graphene oxide is mixed with the hot foaming particles and cooled to form the foaming particles having graphene oxide on the surface. Graphene is combined with the hot foaming particles in the form of solid powder and is easy to adhere.

[0019] The curing agent used in the thermosetting polymer of the present application is not limited, and all curing agents known in the art can be used as long as the performance of the final midsole is not significantly deteriorated.

[0020] Furthermore, in the method for preparing a thermosetting midsole using foamed particles having graphene oxide on the surface, the graphene oxide suspension also contains a binder, which is used to increase the adhesion between the foamed particles.

[0021] Furthermore, in the method for preparing a thermosetting midsole using foamed particles having graphene oxide on the surface, the graphene oxide is sulfonated graphene, the flake diameter of the sulfonated graphene is greater than or equal to 100 microns and less than 1000 microns; the thickness of each sulfonated graphene is 5 to 10 nanometers. In some embodiments, the thickness of the sulfonated graphene is uniformly greater than 90%; the flake diameter of the sulfonated graphene is uniformly greater than 90%.

[0022] Further, the method for preparing a thermosetting midsole using foamed particles having graphene oxide on the surface, wherein the midsole is a midsole with an integrated visual effect, and at least a part of the midsole with an integrated visual effect has an integrated visual effect, that is, there is no popcorn-like pattern in this area, which is called an integrated visual area, is characterized in that the mold is a porous mold, and a plurality of first air holes are provided in a visual part corresponding to the integrated visual area, wherein the area of ​​each of the first air holes is 0.01 square millimeters to 0.25 square millimeters, and the number of the first air holes is greater than 50 per square centimeter, and the method comprises:

[0023] The first step is to place the foamed particles in the mold, and introduce steam at a first temperature into the mold to cause the foamed particles to undergo secondary foaming and fuse with each other to form a midsole precursor;

[0024] The second step is to maintain one or more of the molds in an atmosphere of a second temperature, wherein the second temperature is higher than the first temperature, so that an integrated molding visual effect is formed in the integrated molding visual area of ​​the midsole precursor to form the midsole.

[0025] Dense air holes make it easy to obtain a surface that is more consistent with the surface of the mold. During the high-temperature treatment process, the surface density increases and the tear strength of the visual part is improved. The popcorn pattern disappears, and it has an one-piece molding effect, so that more complex and delicate patterns can be set on its side without being affected by the popcorn pattern.

[0026] Furthermore, the method for preparing a thermosetting midsole using foamed particles having graphene oxide on the surface, wherein the one-piece molding visual effect includes: the one-piece molding visual area does not contain a popcorn-like pattern, and the one-piece molding visual area includes a fine pattern, the fine pattern is a pattern feature with a size of 0.2 mm to 2.0 mm, the pattern feature includes: one or more of protrusions, fine lines, and depressions, and the size of the pattern feature refers to the minimum size of the pattern feature.

[0027] Furthermore, in the method for preparing a thermosetting midsole using foamed particles having graphene oxide on the surface, the thermosetting polymer is selected from: thermosetting phenolic resin, thermosetting urea-formaldehyde resin, thermosetting melamine-formaldehyde resin, thermosetting epoxy resin, thermosetting polyimide, thermosetting polyether nylon elastomer (PEBAX), thermosetting polyester elastomer (TPEE), thermosetting ethylene vinyl acetate polymer (EVA) and thermosetting polyurethane.

[0028] Furthermore, in the method for preparing a thermosetting midsole using foamed particles having graphene oxide on the surface, the one-piece formed visual effect area includes the side of the midsole.

[0029] Furthermore, in the method for preparing a thermosetting midsole using foamed particles having graphene oxide on the surface, a non-visual portion of the mold that does not correspond to the one-piece visual area is provided with a plurality of second air holes, an area of ​​each of the second air holes is greater than 0.3 square millimeters and less than 3 square millimeters, and the number of the second air holes is less than 10 per square centimeter, for example, 0.5 to 3 per square centimeter.

[0030] Large air holes and a small number of distributions keep the appearance of popcorn and a certain degree of roughness, making this shape more suitable for bonding with other materials.

[0031] Furthermore, in the method for preparing a thermosetting midsole using foamed particles having graphene oxide on the surface, the surface of the visual part of the mold has a smaller roughness than the surface of the non-visual part, that is, the non-visual part is rougher.

[0032] Rough edges are easier to bond with other shoe materials such as outsoles, while non-rough visual parts can show better visual effects.

[0033] Furthermore, in the method for preparing a thermosetting midsole using foamed particles having graphene oxide on the surface, the surface of the visual part of the mold is provided with a fine pattern.

[0034] Furthermore, the method for preparing a thermosetting midsole using foamed particles having graphene oxide on the surface, wherein the first temperature is between the softening point temperature of the foamed particles and a temperature 18°C ​​higher than the softening point temperature, the processing time is 1 minute to 5 minutes, and the second temperature is a temperature 20°C to 30°C higher than the first temperature, and the processing time is 1 minute to 5 minutes.

[0035] Further, the polyurethane comprises an aliphatic polyurethane, which is prepared by reacting a liquid composition, wherein the liquid composition comprises: a polyurethane generating component and a reaction catalyst, wherein the polyurethane generating component comprises A) an isocyanate component and B) an isocyanate reactive component, wherein the isocyanate component comprises one or more selected from the following: an aliphatic diisocyanate and an aliphatic polyisocyanate; the isocyanate reactive component comprises: B1) one or more organic polyols with a functionality of 2-3; and B2) a low molecular weight polyvinyl alcohol, wherein the molecular weight of the low molecular weight polyvinyl alcohol is 300 to 10000, wherein the initial viscosity of the liquid composition at 25°C is 50-5000 mPa.s (measured according to DINEN 53019), and the ratio of the number of NCO groups in the isocyanate component to the number of OH groups in the isocyanate reactive component is 1.05:1 – 1.1:1.

[0036] The polyurethane made of the composition has the hydrocarbon skeleton of polyvinyl alcohol, has good biocompatibility, and the polyurethane foam material has at least the effects of temperature resistance and good thermoplasticity, and can realize the stable and controllable molding of the polyurethane foam material under high temperature. The aliphatic isocyanate used in the present application includes hexamethylene diisocyanate, cyclohexylene diisocyanate, isophorone diisocyanate, etc. One or more organic polyols used in the present application include one or more selected from the following: pentaerythritol, ethylene glycol (EG), 1,2-propylene glycol, 1,4-butylene glycol, 1,6-hexanediol, neopentyl glycol (NPG), dipropylene glycol, trimethylolpropane (TMP), glycerol, glycol ether, methyl propylene glycol, polyether polyol, polyether carbonate polyol, polyester polyol, polycarbonate glycol or polyol based on vegetable oil.

[0037] On the other hand, the present application also provides a thermosetting midsole prepared by the method for preparing a thermosetting midsole using foamed particles having graphene oxide on the surface as described above in the present application.

[0038] Furthermore, the thermosetting midsole is a midsole with an integrated visual effect, wherein the midsole with an integrated visual effect is made by subjecting foamed particles to secondary foaming in a mold, and at least a portion of the area has an integrated visual effect, that is, there is no popcorn-like pattern visually in the area, which is called an integrated visual area.

[0039] Furthermore, in the thermosetting midsole, the one-piece molded visual area includes the side of the midsole.

[0040] Furthermore, the thermosetting midsole, wherein the midsole also includes an area visually having a popcorn-like pattern, referred to as a non-integrated visual area, wherein the surface density of the integrally molded visual area is 1.1 times or higher than the surface density of the non-integrated visual area, and the surface density of the integrally molded visual area is 1.3 times or higher than the density of the inner area of ​​the midsole.

[0041] In a specific embodiment, in the non-integrated visual area: the skin density is 0.17 g / cm 3 , the density of the middle part is 0.15g / cm 3 ; In the integrated visual area: skin density 0.195g / cm 3 Left and right, 0.15g / cm in the middle 3 .

[0042] On the other hand, the present application further provides a shoe, which comprises any thermosetting midsole described in the present application.

[0043] On the other hand, the present application also provides a method for preparing a shoe, which comprises preparing a thermosetting midsole according to any method described in the present application.

[0044] In the method of the present application, during the high-temperature fusion process of the graphene oxide on the surface of the foamed particles, the graphene oxide itself also forms a stable chemical bond with the reactive groups on the surface of the foamed particles. The graphene has a multi-layer structure so that the foamed particles where the graphene is present cannot fuse with other foamed particles, thus naturally leaving a breathable channel. In the present application, in many cases, although a through breathable channel cannot be formed, it is believed that even if only some pores are formed, it still has a certain breathable function. Therefore, in the present application, the breathable channel and the pore have the same meaning and can be used interchangeably.

[0045] In the present application, the hydrophilic hydroxyl groups of graphene oxide can react with the reactive groups on the polyurethane to form a stable link, while the hydrophobic structure on the other side prevents the foamed particles from merging in some areas, thus leaving a naturally formed breathable channel on the formed midsole. The channel is mainly formed by graphene oxide.

[0046] Since the amount of graphene oxide added is very small, it does not affect the bonding strength between the foamed particles. At the same time, the air permeable channels left behind can greatly increase the air permeability of the midsole. Due to the presence of graphene, its strong adsorption properties make the midsole have a good deodorizing effect.

[0047] A certain amount of thermosetting polymer is added to the foamed particles in the present application, so that the prepared midsole has better thermal stability, chemical corrosion resistance and support performance, and can be well applied to outdoor sports scenes or production life with extreme conditions.

[0048] The present application also provides a midsole with an integrated visual effect. In the method for manufacturing the midsole, a mold with dense air holes is used. The dense air holes make it easy to obtain a surface that is more consistent with the surface of the mold. During the high-temperature treatment process, the surface density increases, and the tear strength of the visual part is improved. The popcorn pattern disappears, and the midsole has an integrated effect, so that more complex and delicate patterns can be set on its side without being affected by the popcorn pattern. The method still retains the excellent elasticity of the popcorn midsole.

[0049] In addition, the technical solution of the present invention also brings many other advantages, which will be described in detail in the specific implementation manner.

[0050] It is to be understood that the foregoing general description and the following detailed description are exemplary only and are not restrictive of the invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0051] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings of the embodiments will be briefly introduced below. Obviously, the drawings in the following description only relate to some embodiments of the present invention, but are not intended to limit the present invention.

[0052] Figure 1 is a schematic diagram of increased air permeability resulting from the use of graphene oxide;

[0053] Figure 2 It is a photo of the sparse holes of the mold at the non-integrated visual effect;

[0054] Figure 3 This is a photo of the mold's dense holes at the integrated visual effect area. DETAILED DESCRIPTION

[0055] Example embodiments will now be described more fully with reference to the accompanying drawings. However, example embodiments can be implemented in many forms and should not be construed as limited to the embodiments set forth herein; rather, these embodiments are provided so that the present invention will be comprehensive and complete and fully convey the concepts of the example embodiments to those skilled in the art. The same reference numerals in the figures represent the same or similar parts, and thus their repeated description will be omitted.

[0056] In addition, the described features, structures or characteristics may be combined in one or more embodiments in any suitable manner. In the following description, many specific details are provided to provide a full understanding of the embodiments of the present invention. However, those skilled in the art will appreciate that the technical solution of the present invention can be practiced without one or more of the specific details, or other methods, components, devices, steps, etc. may be adopted. In other cases, known methods, devices, implementations or operations are not shown or described in detail to avoid blurring various aspects of the present invention.

[0057] In this application, "wt%" means the percentage by mass / weight.

[0058] Note: In this application, "mass" and "weight" have the same meaning.

[0059] Graphene oxide is an oxide of graphene, generally represented by GO, and its color is brownish yellow. Common products on the market are powder, flake and solution. After oxidation, the number of oxygen-containing functional groups increases, making the properties more active than graphene, and its properties can be improved through various reactions with oxygen-containing functional groups. The graphene oxide described in this application refers to a sheet of graphene having 5 to 30 layers of single-layer graphene (i.e., a thickness of about 1.5 nanometers to 15 nanometers), and the single-layer graphene is connected to a group that can bind to a reactive group. The preferred graphene oxide in this application is sulfonated graphene. WO2015184843A1 discloses a method for preparing sulfonated graphene from organic materials and sulfonated graphene. The graphene prepared by the method may have the following structural characteristics: the sulfonated graphene wherein the sheet diameter of the sulfonated graphene (the plane diameter of the material) is greater than or equal to 100 microns and less than 1000 microns; the thickness of each sulfonated graphene is 5 to 10 nanometers; and the thickness of the sulfonated graphene (the distance in the normal direction of the material plane) is uniformly greater than 90%; the sheet diameter of the sulfonated graphene is uniformly greater than 90%.

[0060] A first aspect of the present application provides a method for preparing a thermosetting midsole using foamed particles having graphene oxide on the surface, the method comprising: fusing the foamed particles having graphene oxide on the surface with each other in a midsole mold under conditions of heating with water vapor to form the thermosetting midsole, wherein the body of the foamed particles having graphene oxide on the surface is formed by mixing 60wt% to 95wt% of a thermoplastic polyurethane and 5wt% to 40wt% of a thermosetting polymer and foaming under non-curing conditions, based on the weight of the body of the foamed particles.

[0061] 5wt% to 40wt% of the foamed particles with graphene oxide on the surface are thermosetting. Thermoplastic polymers are easier to process and reuse, but their thermal stability is poor; while thermosetting polymers are more difficult to process, but have good thermal stability and chemical resistance. The thermosetting midsole prepared in the present application has high mechanical strength, good thermal stability, good chemical resistance, and good air permeability, and is suitable for use in outdoor and extreme environments, such as high temperature weather in the desert, or in a high-temperature production environment. Thermosetting midsole has better support performance. In the production of various outdoor shoe materials requiring high support performance, the midsole is required to have higher support performance. The midsole of the present application is particularly suitable for such application scenarios. In the process of high-temperature fusion of the graphene oxide on the surface of the foamed particles, the graphene oxide itself also forms a stable chemical bond with the reactive groups on the surface of the foamed particles. The graphene has a multi-layer structure so that the foamed particles where there is graphene cannot be fused with other foamed particles, so a breathable channel is naturally left. The breathable channel is made into the midsole of the shoe, and the wearer can fully release the breathability of the midsole by wearing it for about 30,000 steps (different people may have slightly different steps).

[0062] Although the amount of thermosetting polymer used can vary according to the performance required in actual use, the use of thermosetting polymer should not be too high, so as to avoid the hardness of the entire midsole being too high and the resilience being degraded. The resilience described in this application has the meaning generally understood by those skilled in the art, and refers to the performance of the impact object being bounced after the sample is deformed by impact. In some embodiments, the body of the foamed particles with graphene oxide on the surface is formed by mixing 80wt% to 95wt% of thermoplastic polyurethane and 5wt% to 20wt% of thermosetting polymer and foaming under non-curing conditions. In some embodiments, the body of the foamed particles with graphene oxide on the surface is formed by mixing 60wt% to 80wt% of thermoplastic polyurethane and 20wt% to 40wt% of thermosetting polymer and foaming under non-curing conditions. In this application, the conditions for preparing the foamed particles should be carried out under non-curing conditions of the thermosetting polymer, because if it is cured prematurely, the foamed particles form a cured polymer three-dimensional network, and it may not be possible to perform secondary foaming to form the midsole. There is no such limitation in the secondary foaming process, because in the secondary foaming process, the thermosetting polymer is at least partially cured, so that the obtained midsole has high mechanical strength, good thermal stability and good chemical corrosion resistance.

[0063] In the present application, the hydrophilic hydroxyl groups of graphene oxide can react with the reactive groups on polyurethane to form a stable link, while the hydrophobic structure on the other side prevents the foamed particles from merging in some areas, thus leaving a naturally formed breathable channel on the formed midsole. The channel is mainly formed by graphene.

[0064] In addition, due to the presence of graphene, its strong adsorption performance makes the midsole have a good deodorizing effect. In this application, the evaluation of the midsole's air permeability and deodorizing effect is completed in the same experiment. In fact, the air permeability and deodorizing effects are often difficult for the wearer to distinguish. After the shoes are worn, the odor left behind becomes less. Whether it is caused by adsorption or gas flow, it is not necessary for the wearer to distinguish. Therefore, in this application, the deodorizing ability and air permeability of the midsole are evaluated mainly by evaluating the deodorizing property.

[0065] In some embodiments, the method for preparing a midsole using foamed particles, wherein the amount of graphene oxide is 0.05wt% to 2wt% of the foamed particles, that is, the mass / weight of the graphene oxide is 0.05% to 2% of the mass / weight of the foamed particles. Within this range, the amount added can be 0.06wt% to 1wt%, such as 0.07wt% to 0.5wt%, such as 0.08wt% to 0.4wt%, such as 0.09wt% to 0.3wt%, such as 0.1wt% to 0.2wt%.

[0066] Since the amount of graphene oxide added is very small, it does not affect the bonding strength between the foamed particles. At the same time, some breathable channels left behind can greatly increase the breathability of the midsole.

[0067] In some embodiments, the method for preparing a midsole using foamed particles, wherein the foamed particles having graphene oxide on the surface are prepared as follows: a mixture of 60wt% to 95wt% of thermoplastic polyurethane and 5wt% to 40wt% of thermosetting polymer is foamed under non-curing conditions to form a foamed particle body, based on the total weight of the initial foamed particles; a suspension of graphene oxide is contacted with the foamed particle body to obtain foamed particles having graphene oxide on the surface. In these embodiments, the graphene oxide is physically combined with the foamed particles in the form of a suspension, and a strong chemical bond is formed during the secondary foaming process.

[0068] In some embodiments, the method for preparing a midsole using foamed particles, wherein the foamed particles having graphene oxide on the surface are prepared as follows: 60wt% to 95wt% of thermoplastic polyurethane and 5wt% to 40wt% of thermosetting polymer are mixed to form a mixture matrix in a molten state; the mixture matrix in a molten state is fully mixed with a foaming agent in a supercritical state (such as carbon dioxide or nitrogen or other gases) to form a single-phase mixed sol;

[0069] The single-phase mixed sol is passed through an extrusion die to enter a normal pressure state, so that a large number of bubble nuclei are precipitated from the foaming agent and expand to obtain hot foamed particles;

[0070] The powdered graphene oxide is mixed with the hot foamed particles and cooled to form the foamed particles having graphene oxide on the surface.

[0071] In these embodiments, the graphene oxide is combined with hot foamed particles in the form of solid powder, which is easy to adhere to, and the obtained foamed particles with graphene oxide on the surface can be directly used to form the midsole.

[0072] In some embodiments, in the method for preparing a midsole using foamed particles, the graphene oxide suspension further contains a binder. The added binder is used to increase the adhesion between the foamed particles to compensate for the reduced adhesion between the foamed particles that may be caused by the graphene oxide.

[0073] In some embodiments, the method of preparing a midsole using foamed particles, wherein the graphene oxide is sulfonated graphene, the flake diameter of the sulfonated graphene (the plane diameter of the material) is greater than or equal to 100 microns to less than 1000 microns; the thickness of each sulfonated graphene is 5 to 10 nanometers; and the thickness of the sulfonated graphene (the distance in the normal direction of the material plane) is uniformly greater than 90%; the flake diameter of the sulfonated graphene is uniformly greater than 90%.

[0074] The sulfonated graphene specifically used in the present application is a type of graphene oxide, and the oxidation of graphene is achieved by sulfonation, and is prepared according to the specific method in Example 4 disclosed in WO2015184843A1.

[0075] In the method of the present application, when a thermosetting polymer is used, the prepared midsole is a thermosetting midsole. Those skilled in the art should understand that if the body of the foamed particles is replaced with a thermoplastic material such as thermoplastic polyurethane, a thermoplastic midsole can still be obtained, and the midsole still has excellent deodorizing ability and air permeability. Therefore, the midsole described in the present application generally refers to a thermosetting midsole, and the terms "midsole" and "thermosetting midsole" can be used interchangeably; however, when all the polymer materials used in the midsole are thermoplastic materials, it refers to a thermoplastic midsole.

[0076] The method of the present application can also be used to prepare a midsole with an integrally formed visual effect. Usually, a popcorn sole does not have an integrally formed visual effect. On the contrary, the presence of a popcorn visual effect can be clearly seen from the side of the midsole. In some embodiments, the method of preparing a midsole using foamed particles, wherein the midsole is a midsole with an integrally formed visual effect, and at least part of the midsole with an integrally formed visual effect has an integrally formed visual effect, that is, there is no popcorn-like pattern in this area, which is called an integrally formed visual area, and is characterized in that the mold is a porous mold, and a plurality of first air holes are provided in the visual part corresponding to the integrally formed visual area, wherein the area of ​​each of the first air holes is 0.01 square millimeters to 0.25 square millimeters, and the number of the first air holes is greater than 50 / square centimeter, and the method comprises:

[0077] The first step is to place the foamed particles in the mold, and introduce steam at a first temperature into the mold to cause the foamed particles to undergo secondary foaming and fuse with each other to form a midsole precursor;

[0078] The second step is to maintain one or more of the molds in an atmosphere of a second temperature, wherein the second temperature is higher than the first temperature, so that an integrated molding visual effect is formed in the integrated molding visual area of ​​the midsole precursor to form the midsole.

[0079] This embodiment has a special technical effect. The dense air holes can easily obtain a surface that is more consistent with the surface of the mold. During the high-temperature treatment process, the surface density increases and the tear strength of the visual part is improved. The popcorn pattern disappears, and it has an one-piece molding effect, so that more complex and delicate patterns can be set on its surface without being affected by the popcorn pattern.

[0080] In some embodiments, the method of preparing a midsole using foamed particles, wherein the one-piece molding visual effect includes: the one-piece molding visual area does not contain a popcorn-like pattern, and the one-piece molding visual area includes a fine pattern, the fine pattern is a pattern feature with a size of 0.2 mm to 2.0 mm, the pattern feature includes: one or more of protrusions, fine lines, and depressions, and the size of the pattern feature refers to the minimum size of the pattern feature.

[0081] The thermosetting polymer used in this application is not particularly limited, as long as the technical effect of this application can be achieved. In some embodiments, the method of preparing a midsole using foamed particles, wherein the thermosetting polymer is selected from thermosetting phenolic resin, thermosetting urea-formaldehyde resin, thermosetting melamine-formaldehyde resin, thermosetting epoxy resin, thermosetting polyurethane, thermosetting polyimide, thermosetting polyether nylon elastomer (pebax), thermosetting polyester elastomer (TPEE), thermosetting ethylene vinyl acetate polymer (EVA) and thermosetting polyurethane. Thermosetting polymers can generally be obtained by mixing a polymer with a curing agent (e.g., a cross-linking agent) and an optional auxiliary agent (e.g., a co-cross-linking agent). For example, a thermosetting ethylene vinyl acetate polymer is obtained by blending an ethylene vinyl acetate polymer with 0.5 wt% to 0.8 wt% of a cross-linking agent TBEC and 0.6 to 0.8 wt% of a co-cross-linking agent TAIC; a thermosetting polyurethane is obtained by blending an uncapped polyurethane with an amine / alcohol chain extender; and a thermosetting polyether nylon elastomer (pebax) is obtained by blending a polyether nylon elastomer with a chain extender.

[0082] In some embodiments, in the method of preparing a midsole using foamed particles, the integrally formed visual effect area includes the side of the midsole.

[0083] In some embodiments, the method of preparing a midsole using foamed particles, wherein the non-visual portion of the mold that does not correspond to the one-piece visual area is provided with a plurality of second air holes, the area of ​​each of the second air holes is greater than 0.3 square millimeters and less than 3 square millimeters, and the number of the second air holes is less than 10 per square centimeter, for example, 0.5 to 3 per square centimeter.

[0084] In non-visual areas, the mold uses large ventilation holes with a small distribution number, so that the midsole retains the appearance of popcorn and retains some roughness. This shape is more suitable for bonding with other materials.

[0085] In some embodiments, in the method for preparing a midsole using foamed particles, the surface of the visual part of the mold has a smaller roughness than the surface of the non-visual part, that is, the non-visual part is rougher. In this embodiment, the rough edge is easier to bond with other shoe materials such as the outsole. The visual part is not rough and can show a better visual effect.

[0086] In some embodiments, in the method of preparing a midsole using foamed particles, the surface of the visual part of the mold is provided with a fine pattern.

[0087] In some embodiments, the method of preparing a midsole using foamed particles, wherein the first temperature is between the softening point temperature of the foamed particles and a temperature 18°C ​​higher than the softening point temperature, the processing time is 1 minute to 5 minutes, and the second temperature is a temperature 20°C to 30°C higher than the first temperature, and the processing time is 1 minute to 5 minutes.

[0088] In some embodiments, the polyurethane comprises an aliphatic polyurethane, which is prepared by reacting a liquid composition, wherein the liquid composition comprises: a polyurethane generating component and a reaction catalyst, wherein the polyurethane generating component comprises A) an isocyanate component and B) an isocyanate reactive component, wherein the isocyanate component comprises one or more selected from the following: an aliphatic diisocyanate and an aliphatic polyisocyanate; the isocyanate reactive component comprises: B1) one or more organic polyols having a functionality of 2-3; B2) a low molecular weight polyvinyl alcohol, wherein the molecular weight of the low molecular weight polyvinyl alcohol is 300 to 10000, wherein the initial viscosity of the liquid composition at 25°C is 50-5000 mPa.s (measured according to DIN EN 53019), and the ratio of the number of NCO groups in the isocyanate component to the number of OH groups in the isocyanate reactive component is 1.05:1 – 1.1:1.

[0089] The aliphatic polyurethane polymer prepared in this embodiment is particularly suitable for preparing the midsole described in this application. The polyurethane prepared by the composition disclosed in this method has a hydrocarbon skeleton of polyvinyl alcohol and has good biocompatibility. The polyurethane foam material has at least good thermoplasticity and stable mold shrinkage, and can achieve stable and controllable shaping of the polyurethane foam material under high temperature.

[0090] The reaction catalyst is a latent catalyst which catalyzes at a temperature of 60° C. to 100° C. The weight content of the reaction catalyst is 0.01 to 6 parts by weight, calculated based on 100 parts by weight of the polyurethane generating components.

[0091] There is no restriction on the type of catalyst used in the present application, as long as it is suitable for the chemical reaction in the present application. In some embodiments, the reaction catalyst can be one or more of aromatic amines, imidazoles, acid anhydrides, dicyandiamides, organic hydrazide compounds, such as cyanoguanidine, 4,4'-diaminodiphenyl sulfone, N-acyl imidazole compounds, and cyanoacetyl compounds. In a specific embodiment, the catalyst that can be used includes tertiary amines or organotin catalysts, such as N, N-dimethylcyclohexylamine, tetramethylethylenediamine, tetramethylbutylene diamine, N, N'-dimethylpiperazine, triethylenediamine, triethanolamine and dimethylethanolamine, dimethylbenzylamine, N-ethylmorpholine, pentamethyldiethylenetriamine and triethylamine, and the organotin catalyst is such as stannous octoate.

[0092] The liquid composition may further include at least one auxiliary agent selected from the group consisting of a defoamer, a mold release agent, a leveling agent, a durability aid, a flow aid, an organic color powder, an inorganic color powder, and a color paste.

[0093] The present application also provides a midsole prepared by any of the methods described in the present application.

[0094] In some embodiments, the midsole described in the present application is a midsole with an integrated visual effect, wherein the midsole with an integrated visual effect is made by subjecting foamed particles to secondary foaming in a mold, and at least a portion of the area has an integrated visual effect, that is, there is no visually popcorn-like pattern in the area, which is called an integrated visual area.

[0095] In some embodiments, in the midsole described in the present application, the integrally formed visual area includes a side surface of the midsole.

[0096] In some embodiments, the midsole described in the present application further includes an area having a pattern similar to popcorn visually, referred to as a non-integrated visual area, wherein the surface density of the integrally formed visual area is 1.1 times or more of the surface density of the non-integrated visual area, and the surface density of the integrally formed visual area is 1.3 times or more of the density of the inner area of ​​the midsole. In a specific embodiment, in the non-integrated visual area: the surface density is 0.17 g / cm 3 The density of the middle part is 0.15g / cm 3 ; In the integrated visual area: skin density 0.195g / cm 3 The density of the middle part is 0.15g / cm 3The epidermis part mentioned in the present application refers to the part within 2mm thickness of the midsole surface, and the middle part refers to the part greater than or equal to 3mm from the surface. Generally speaking, the density of the epidermis part is higher than that of the middle part. In the present application, the epidermis density of the integrally molded visual area is higher than that of the non-integrated visual area, which further increases the mechanical strength and toughness of the epidermis of the integrally molded visual area and increases the durability of the shoe.

[0097] In some embodiments, the method for preparing a midsole using foamed particles, wherein the thermosetting polymer is selected from thermosetting phenolic resin, thermosetting urea-formaldehyde resin, thermosetting melamine-formaldehyde resin, thermosetting epoxy resin, thermosetting polyurethane, thermosetting polyimide, thermosetting polyether nylon elastomer (pebax), thermosetting polyester elastomer (TPEE), thermosetting ethylene vinyl acetate polymer (EVA) and thermosetting polyurethane.

[0098] In some embodiments, in the midsole described in the present application, the foamed particles contain: 80wt% to 90wt% of at least one of the following polyurethanes: polyester polyurethane, polyether polyurethane, aliphatic polyurethane, or a combination thereof; and 10wt% to 20wt% of the thermosetting polymer.

[0099] In some embodiments, in the midsole described in the present application, the foamed particles contain: 85wt% to 95wt% of at least one of the following polyurethanes: polyester polyurethane, polyether polyurethane, aliphatic polyurethane, or a combination thereof; and 5wt% to 15wt% of the thermosetting polymer.

[0100] The present application also provides a shoe, which comprises the midsole according to the present application.

[0101] The present application also provides a method for preparing shoes, which comprises preparing a midsole according to the method.

[0102] Generally speaking, thermosetting polymers are cured under certain curing conditions, and the main curing conditions include curing time and curing temperature. Taking thermosetting EVA resin as an example, the curing conditions of thermosetting EVA resin mainly include temperature and time. The curing process of thermosetting EVA resin is to generate free radicals in the cross-linking agent in EVA by heating, so that the EVA molecules are cross-linked to form a three-dimensional network structure, thereby completing the curing. This process needs to be carried out at a certain temperature to ensure that the fluidity of the EVA resin is good and to facilitate the formation of a uniform three-dimensional network structure to obtain the required performance. Specifically, the curing conditions of EVA resin include: curing temperature and curing time. At the curing temperature, the EVA resin softens, the foaming agent gas in the resin expands to further expand the foaming particles, and the cross-linking agent in the EVA resin generates free radicals, and the EVA molecules undergo cross-linking reactions to form a three-dimensional network structure. At this time, the fluidity becomes worse and the viscosity increases. The length of the curing time depends on the specific curing conditions and the type of curing agent in the EVA resin. Keep it at an appropriate temperature for a period of time to ensure that the cross-linking reaction is fully carried out and a stable network structure is formed. In the present application, since complete curing is not required, the curing time usually only needs 1-5 minutes.

[0103] It should be noted that during the curing process, excessive heating should be avoided. If the temperature exceeds the curing temperature, the cross-linking agent may decompose and produce gas. At the same time, the cross-linking degree of EVA decreases, and vulcanization, yellowing, shrinkage and other phenomena may occur.

[0104] The present application will be more specifically illustrated by the following examples. Example

[0105] Table 1 Raw materials and sources

[0106]

[0107] Example 1 [Method for preparing aliphatic polyurethane]

[0108] The polyurethane used in the present application is an aliphatic polyurethane, which is prepared by reacting a liquid composition, wherein the liquid composition comprises: a polyurethane generating component and a reaction catalyst, wherein the polyurethane generating component comprises A) an isocyanate component and B) an isocyanate reactive component, wherein the isocyanate component comprises one or more selected from the following: an aliphatic diisocyanate and an aliphatic polyisocyanate; the isocyanate reactive component comprises: B1) one or more organic polyols with a functionality of 2-3; B2) a low molecular weight polyvinyl alcohol, wherein the molecular weight of the low molecular weight polyvinyl alcohol is 300 to 10000, wherein the initial viscosity of the liquid composition at 25°C is 50-5000 mPa.s (measured according to DIN EN53019), and the ratio of the number of NCO groups in the isocyanate component to the number of OH groups in the isocyanate reactive component is 1.05:1 – 1.1:1.

[0109] The reaction catalyst is a latent catalyst which catalyzes at a temperature of 60° C. to 100° C. The weight content of the reaction catalyst is 0.01 to 6 parts by weight, calculated based on 100 parts by weight of the polyurethane generating components.

[0110] Specifically, first, 30 parts by weight of hexamethylene diisocyanate and 30 parts by weight of polyisocyanate are mixed at room temperature to form the isocyanate component as liquid 1, and 0.3 parts by weight of stannous octoate and 0.2 parts by weight of N,N-dimethylcyclohexylamine are added to the liquid 1 as a chemical reaction catalyst, and then 40 parts by weight of polyvinyl alcohol, 19 parts by weight of dipropylene glycol and polyether polyol are added to the liquid 1 and mixed evenly to obtain the liquid composition, and the initial viscosity of the liquid composition at 25°C is measured to be 300 mPa.s (measured according to DIN EN 53019), and the ratio of the number of NCO groups in the isocyanate component to the number of OH groups in the B) isocyanate reactive component is about 1.08: 1. The liquid composition is heated to 70°C under stirring to start the reaction, and the temperature of the reaction system is maintained below 130°C for about 1 hour until the viscosity no longer increases to stop the reaction, and the reaction is cooled and granulated to obtain aliphatic polyurethane in granular form, and its melting point is measured to be 153°C.

[0111] The aliphatic polyurethane polymer prepared in this embodiment is particularly suitable for preparing the midsole described in this application. The polyurethane prepared by the composition disclosed in this method has a hydrocarbon skeleton of polyvinyl alcohol and has good biocompatibility. The polyurethane foam material has at least the effects of temperature resistance, good thermoplasticity, and stable mold shrinkage rate, and can achieve stable and controllable shaping of the polyurethane foam material under high temperature conditions.

[0112] Example 2 [Preparation of foamed particles by one-step foaming of supercritical fluid]

[0113] The granular aliphatic polyurethane obtained in Example 1 was mixed with a thermosetting polymer to prepare a composition, and then foamed particles were prepared by a supercritical fluid foaming method.

[0114] The thermosetting polymer is thermosetting EVA, which is obtained by fully mixing 100 parts by weight of EVA (melting point 70° C.), 0.5 parts by weight of a crosslinking agent TBEC (tert-butyl peroxy-2-ethyl ethyl carbonate), and 0.6 parts by weight of an auxiliary crosslinking agent TAIC (triallyl isocyanurate) at 75° C.

[0115] 85 parts by weight of the polyurethane particles obtained in Example 1 and 15 parts by weight of the thermosetting EVA are mixed at 155° C. to obtain a molten mixture matrix; the molten mixture matrix is ​​fully mixed with a supercritical foaming agent (carbon dioxide, temperature is 65° C., pressure is 200 bar) to form a single-phase mixed sol; the single-phase mixed sol is passed through an extrusion die to enter a normal pressure state, so that the foaming agent precipitates a large number of bubble nuclei and expands to obtain hot foamed particles, wherein the size of a single foamed particle is 0.8 to 1.5 cm, and the density is about 0.16 g / cm 3 .

[0116] Example 3 [Combining graphene oxide powder on the basis of Example 2]

[0117] 0.5 wt% of powdered graphene oxide based on the weight of the polyurethane particles is mixed with the hot foamed particles and cooled to form the foamed particles having graphene oxide on the surface. The foamed particles obtained here are the first type of foamed particles having graphene oxide on the surface.

[0118] In this embodiment, the powdered graphene oxide is combined with the hot foaming particles in the form of solid powder, which is easy to adhere. In this embodiment, the graphene oxide is sulfonated graphene, wherein the sheet diameter (the plane diameter of the material) of the sulfonated graphene is greater than or equal to 100 microns to less than 1000 microns; the thickness of each sulfonated graphene is 5 to 10 nanometers; and the thickness of the sulfonated graphene (the distance in the normal direction of the material plane) is more than 90%; the sheet diameter of the sulfonated graphene is more than 90%.

[0119] Example 4 [Using graphene oxide suspension to set graphene oxide on foamed particles]

[0120] The hot expanded beads obtained in Example 2 were cooled to obtain expanded beads.

[0121] Graphene oxide, sodium dodecyl sulfate and water are prepared together to form a graphene oxide suspension.

[0122] The graphene oxide suspension is mixed with the foamed particles and dried to obtain second foamed particles having graphene oxide on the surface.

[0123] Graphene oxide is physically combined with foaming particles in the form of a suspension, and a strong chemical bond is formed during the secondary foaming process.

[0124] Example 5 [Secondary foaming of water vapor to prepare midsole]

[0125] The (first or second) foamed particles having graphene oxide on the surface are fused with each other in a midsole mold under the condition of heating with water vapor to form the midsole.

[0126] The midsole is a midsole with an integrated visual effect, and at least a part of the midsole with an integrated visual effect has an integrated visual effect, that is, there is no popcorn-like pattern in this area, which is called an integrated visual area. The mold is a porous mold, and a plurality of first air holes are provided in a visual part corresponding to the integrated visual area, wherein the area of ​​each of the first air holes is 0.01 square millimeters to 0.25 square millimeters, and the number of the first air holes is greater than 50 per square centimeter. The method comprises: a first step, placing the foamed particles In the mold, steam at 158°C is introduced into the mold to cause the foamed particles to undergo secondary foaming and fuse with each other to form a midsole precursor. In the second step, one or more of the molds are maintained in an atmosphere at 180°C to form an integrated visual effect in the integrated visual area of ​​the midsole precursor to form the midsole 5-1 and the midsole 5-2, wherein the midsole 5-1 is prepared using the first type of foamed particles having graphene oxide on the surface obtained in Example 3, and the midsole 5-2 is prepared using the second type of foamed particles having graphene oxide on the surface obtained in Example 4.

[0127] In this embodiment, the first temperature is 158°C, which is 5°C higher than the softening point of the foamed particles, and the processing time is 3 minutes. The second temperature is 180°C, which is 22°C higher than the first temperature, and the processing time is 3 minutes.

[0128] Specifically, in this embodiment, foamed particles with an average diameter of 2 mm formed by mixing polyester polyurethane and thermosetting polymer are placed in a 40-yard midsole mold, the mold is a porous mold, the area of ​​the air holes is 0.01 square millimeters, and the number of first air holes is 100 per square centimeter. The mold is provided with a plurality of second air holes in the non-visual part that does not correspond to the one-piece visual area, the area of ​​each second air hole is 0.8 square millimeters, and the number of the second air holes is 3 per square centimeter. The non-visual part of the mold is rougher than the visual part. Figure 2 and Figure 3 are photos of the mold, which are photos of the mold with sparse holes at the non-integrated visual effect area, and photos of the mold with dense holes at the integrated visual effect area.

[0129] During the high-temperature fusion process of graphene oxide on the surface of the foamed particles, the graphene oxide itself forms a stable chemical bond with the reactive groups on the surface of the foamed particles. The graphene has a multi-layer structure, so the foamed particles where there is graphene cannot fuse with other foamed particles, thus naturally leaving a breathable channel.

[0130] In the present application, the hydrophilic hydroxyl groups of graphene oxide can react with the reactive groups on polyurethane to form a stable link, while the hydrophobic structure on the other side prevents the foamed particles from merging in some areas, thus leaving a naturally formed breathable channel on the formed midsole. The channel is mainly formed by graphene.

[0131] Since the amount of graphene oxide added is very small, it does not affect the bonding strength between the foamed particles. At the same time, some breathable channels left behind can greatly increase the breathability of the midsole.

[0132] The technical effect of this embodiment is that the obtained thermosetting midsole has high mechanical strength, good thermal stability and good chemical corrosion resistance. The dense air holes in the midsole mold can easily obtain a surface that is more consistent with the surface of the mold. During the high-temperature treatment, the surface density increases, and the tear strength of the visual part is improved. The popcorn pattern disappears, and it has an integrated molding effect, so that more complex and delicate patterns can be set on its side without being affected by the popcorn pattern. In the non-integrated molding visual area, the surface density is 0.17g / cm 3 , the density of the middle part is 0.15g / cm 3 ; In the integrated visual area, the surface density is 0.195g / cm 3 , the density of the middle part is 0.15g / cm 3 .

[0133] Embodiment 6 [Shoemaking]

[0134] The midsole 5-1 and the midsole 5-2 in Example 5 are made into shoes 5-1 and shoes 5-2 respectively.

[0135] The specific method is to bond the midsole to the rubber outsole, combine it with the upper, and set the insole.

[0136] Example 7 [Using the particles obtained in Example 2, without adding graphene oxide, to directly prepare shoes]

[0137] The hot foamed particles obtained in Example 2 were cooled to obtain foamed particles. The midsole was prepared by the method of Example 5, and the shoe 5-3 was prepared by the method of Example 6. Example

[0138] The method of Example 5 was adopted to prepare the midsole, and the method of Example 6 was adopted to make the shoe, except that commercially available foamed particles (polyester polyurethane-A1, polyether polyurethane-A2, aliphatic polyurethane-A3, modified nylon elastomer Pebax-A4, polyester elastomer TPEE-A5, ethylene-vinyl acetate copolymer EVA-A6) were used to obtain shoes A1, shoes A2, shoes A3, shoes A4, shoes A5, and shoes A6. Example

[0139] The method of Example 4 is adopted to make the surface of the foamed particles have graphene oxide, except that commercially available foamed particles (polyester polyurethane-B1, polyether polyurethane-B2, aliphatic polyurethane-B3, modified nylon elastomer Pebax-B4, polyester elastomer TPEE-B5, ethylene-vinyl acetate copolymer EVA-B6) are used to prepare the foamed particles with graphene oxide on the surface.

[0140] The method of Example 5 was used to prepare the midsole, and the method of Example 6 was used to make the shoe, to obtain shoe B1, shoe B2, shoe B3, shoe B4, shoe B5, and shoe B6.

[0141] Comparative Example 10

[0142] The method of Example 5 is adopted to prepare the midsole, and the method of Example 6 is adopted to make the shoe, except that the following foamed particles are used (foamed particles-5-4 of Example 2, polyester polyurethane-C1, polyether polyurethane-C2, aliphatic polyurethane-C3, modified nylon elastomer Pebax-C4, polyester elastomer TPEE-C5, ethylene-vinyl acetate copolymer EVA-C6), and the second step is not performed, that is, the step of "maintaining one or more of the molds in an atmosphere of the second temperature" is not performed, and the obtained midsole precursor is directly used to make shoes to obtain shoes 5-4, shoes C1, shoes C2, shoes C3, shoes C4, shoes C5, and shoes C6.

[0143] Test [shoes 5-1 to 5-4, A1-A6, B1-B6, C1-C6]

[0144] The obtained shoes were put to the test by wearing them for about 30,000 steps before the test to completely activate the graphene oxide breathable channels.

[0145] Two parallel experiments were performed for each test.

[0146] Parallel test 1 [left foot comparison example 10, right foot implementation example] Exercise for one day, about 30,000 steps.

[0147] Parallel test 2 [right foot comparison example 10, left foot example] Exercise for one day, about 30,000 steps.

[0148] The shoes prepared in each embodiment were compared with the shoes prepared with the same midsole material in Comparative Example 10, and the odor of the two shoes was evaluated, and the results were averaged from the two tests. That is, shoes 5-1 to 5-3 were compared with shoe 5-4 in Comparative Example 10 as a group, and all the test values ​​of shoe 5-4 were averaged, shoes A1 and B1 were compared with C1 in Comparative Example 10 as a group, and all the test values ​​of shoe C1 were averaged, shoes A2 and B2 were compared with C2 in Comparative Example 10 as a group, and all the test values ​​of shoe C2 were averaged, and so on.

[0149] The odor is divided into 11 levels from 0 to 10. Among them, when the odor level is 0, the odor is the least, and when the odor level is 10, the odor is the strongest.

[0150] The increase in surface density and tear strength refers to the increase in the values ​​of the integrated visual effect area of ​​the midsole relative to the values ​​of the non-integrated visual effect area. Specifically, if the surface density of the non-integrated visual area is 0.17 g / cm 3 The skin density in the integrated visual area is 0.195g / cm 3 , the increase in epidermis density is 14.7%. It should be noted that the surface density of the one-piece visual effect area is 1.3 times or higher than the density of the inner area of ​​the midsole. The specific measurement values ​​are not given separately in the table. The tear strength of the sole is tested using the ASTM D-624 standard. First, a sheet with a thickness of 2 mm containing the epidermis is cut from the area to be tested, and then it is punched out with a punch, and the tear strength is tested using a tensile testing machine (in kg / cm). It should be noted that the tear strength of the one-piece visual effect area is important because, under normal circumstances, the one-piece visual effect area is susceptible to external shear forces during movement.

[0151] Heat resistance is measured by measuring the Vicat softening point temperature. Resilience refers to the ability of the sole to bounce back the impacted object after being deformed by impact, and is measured according to DB35∕T 1937-2020.

[0152] In Table 1, the mass / weight proportions of thermoplastic polyurethane and thermosetting polymer are 85% and 15%, respectively.

[0153] Table 2. Test results

[0154]

[0155] The exemplary embodiments of the present disclosure are specifically shown and described above. It should be understood that the present disclosure is not limited to the detailed structures, configurations or implementations described herein; on the contrary, the present disclosure is intended to cover various modifications and equivalent configurations included in the spirit and scope of the appended claims.

Claims

1. A method for preparing a thermosetting midsole using foamed particles, characterized in that: The method comprises: The foamed particles with graphene oxide on the surface are made to fuse with each other in a midsole mold under the condition of heating with water vapor to form the thermosetting midsole, wherein the body of the foamed particles with graphene oxide on the surface is formed by mixing 60wt% to 95wt% of thermoplastic polyurethane and 5wt% to 40wt% of thermosetting polymer in the body of the foamed particles and foaming under non-curing conditions; wherein at least a part of the thermosetting midsole has an integrally formed visual effect, the integrally formed visual effect does not contain a popcorn-like pattern, and the integrally formed visual effect includes a fine pattern, the fine pattern is a pattern feature having a size of 0.2 mm to 2.0 mm, the pattern feature includes one or more of convexities, fine lines, and concavities, and the size of the pattern feature refers to the minimum size of the pattern feature; the midsole mold is a porous mold, which is provided with a plurality of first air holes corresponding to the integrally formed visual effect area, wherein the area of ​​each of the first air holes is 0.01 square millimeters to 0.25 square millimeters, and the number of the first air holes is greater than 50 per square centimeter; and the method comprises: a first step, placing the foaming particles in the midsole mold, and introducing steam at a first temperature into the midsole mold to cause the foaming particles to undergo secondary foaming and fuse with each other to form a midsole precursor; The second step is to maintain one or more of the midsole molds in an atmosphere of a second temperature, wherein the second temperature is higher than the first temperature, so that an integrated visual effect is formed on the midsole precursor to form the midsole.

2. The method for preparing a thermosetting midsole using foamed particles according to claim 1, characterized in that: The amount of the graphene oxide is 0.05wt% to 2wt% of the bulk of the foamed particles.

3. The method for preparing a thermosetting midsole using foamed particles according to claim 1, characterized in that: The foamed particles having graphene oxide on the surface are prepared as follows: a mixture of 60wt% to 95wt% of thermoplastic polyurethane and 5wt% to 40wt% of thermosetting polymer is foamed under non-curing conditions to form a foamed particle body, based on the total weight of the foamed particle body; a suspension of graphene oxide is contacted with the foamed particle body to obtain foamed particles having graphene oxide on the surface.

4. The method for preparing a thermosetting midsole using foamed particles according to claim 2, characterized in that: The graphene oxide is sulfonated graphene, the sheet diameter of the sulfonated graphene is greater than or equal to 100 micrometers and less than 1000 micrometers; the thickness of the sulfonated graphene is 5 to 10 nanometers.

5. The method for preparing a thermosetting midsole using foamed particles according to claim 1, characterized in that: The thermosetting polymer is selected from: Thermosetting phenolic resins, thermosetting urea-formaldehyde resins, thermosetting melamine-formaldehyde resins, thermosetting epoxy resins, thermosetting polyimides, thermosetting polyether nylon elastomers, thermosetting polyester elastomers, thermosetting ethylene vinyl acetate polymers and thermosetting polyurethanes.

6. The method for preparing a thermosetting midsole using foamed particles according to claim 1, characterized in that: The one-piece visual effect area includes the side of the midsole.

7. The method for preparing a thermosetting midsole using foamed particles according to claim 1, characterized in that: The first temperature is between the softening point of the foamed particles and a temperature 18°C ​​higher than the softening point, and the processing time is 1 minute to 5 minutes. The second temperature is a temperature 20°C to 30°C higher than the first temperature, and the processing time is 1 minute to 5 minutes.

8. A thermosetting midsole, characterized in that: It is prepared according to the method for preparing a thermosetting midsole using foamed particles according to any one of claims 1 to 7.

9. The thermosetting midsole according to claim 8, characterized in that: It is a midsole with an integrally molded visual effect, wherein the integrally molded visual effect area includes the side of the midsole, wherein the midsole also includes an area visually having a popcorn-like pattern, called a non-integrated visual effect area, wherein the surface density of the integrally molded visual effect area is 1.1 times or higher than the surface density of the non-integrated visual effect area, and the surface density of the integrally molded visual effect area is 1.3 times or higher than the density of the inner area of ​​the midsole.

10. A shoe comprising the thermosetting midsole according to any one of claims 8 to 9.

11. A method for preparing shoes, comprising preparing a thermosetting midsole by using the method for preparing a thermosetting midsole using foamed particles according to any one of claims 1 to 7.

Images