Multi-color multi-density sole

Abstract

This invention relates to the field of shoe sole technology, specifically to a multi-color, multi-density shoe sole. The sole is formed by molding foam beads A, B, and C using a shoe sole mold. Magnetic responsive fibers are dispersed within foam beads B and C. A first foaming agent is dispersed within foam beads B, and color-developing microparticles are dispersed within foam beads C. These color-developing microparticles are composed of a mixture of photochromic material and pigment. Magnetic responsive fibers are distributed within the color-developing microparticles, and a second foaming agent is distributed within the magnetic responsive fibers. Through a combination of physical and chemical foaming, under the influence of an external magnetic field, different areas of the shoe sole exhibit regular density changes, allowing the sole to better conform to the foot and improve wearing comfort. Furthermore, based on the penetration of magnetic responsive fibers into adjacent foam beads, combined with the three-stage foaming process, the bonding strength between adjacent foam beads is improved, effectively solving the technical problems of existing bead-foamed shoe soles being prone to tearing along the weld interface and having low tear resistance.

Description

Technical Field

[0001] This invention relates to the field of shoe soles, and more particularly to a multi-color, multi-density shoe sole. Background Technology

[0002] Supercritical foaming technology is widely used in high-end sports shoes. By converting N2 / CO2 into supercritical gas and injecting it into the sole material for full diffusion, and then rapidly depressurizing to generate a pressure drop, the gas can be released to form a large number of bubble nuclei, which can produce countless tiny and uniform pores in the sole. Because gas is used as a foaming agent, there are few chemical residues, which is very environmentally friendly.

[0003] The production process of bead-foamed shoe soles mainly includes two steps: first, TPU granules are foamed using supercritical fluid extraction to create popcorn-sized ETPU beads; then, the beads are filled into a shoe sole mold, and heated to fuse their surfaces, ultimately forming the shape of the shoe sole. Currently, bead-foamed shoe soles have several drawbacks: Firstly, because the beads are connected by welding and are not an integrated structure, the sole is prone to tearing and cracking along the welding interface. This is the main reason why the tear strength and toughness of bead foam soles are not ideal. The movement of the beads is uncontrollable during the second bead foaming process. If the functionality of the sole is to be improved, it is usually necessary to carve grooves and combine them with other shoe materials with different foaming rates. Thirdly, foamed soles typically use coatings to create patterns and colors on the sole surface. However, these coatings are easily peeled off due to friction, which can affect the appearance of the sole. The purpose of this invention is to propose a new sole structure to solve the above-mentioned technical problems. Summary of the Invention

[0004] The purpose of this invention is to provide a multi-color, multi-density shoe sole to solve the problems mentioned in the background art.

[0005] To achieve the above objectives, the present invention provides the following technical solution: a multi-color, multi-density shoe sole, wherein the shoe sole is formed by molding foam beads A, foam beads B, and foam beads C using a shoe sole mold. Foam beads A, B, and C are prepared by foaming the same polymer. Using the same material helps to improve the compatibility between foam beads A, B, and C, and inhibits tearing and cracking of the shoe sole. A first foaming agent is dispersed in foam beads B, and micron-sized color-developing microparticles are dispersed in foam beads C. The color-developing microparticles are composed of a mixture of photochromic material and pigment. Magnetic responsive fibers are distributed within foam beads B and the color-developing microparticles. The magnetic responsive fibers are composed of nano-γ-Fe2O3 dispersed within PP fibers. A second foaming agent is distributed within the magnetic responsive fibers. Here, the terms "first" and "second" of the first and second foaming agents are only used to indicate the order and have no practical significance. The specific composition of the foaming agent is not the technical content to be protected by the inventor, and therefore will not be further disclosed.

[0006] Magnetic responsive fiber, also known as magnetic fiber, refers to a type of chemical fiber in which magnetic substances are dispersed and the fiber possesses magnetic properties. Its preparation process and working principle are known to those skilled in the art, so they will not be explained further. In specific implementation, technicians can adjust the parameters of the magnetic responsive fiber (such as fineness, length, strength, resilience, crimp, etc.) according to actual needs. The Curie point temperature of γ-Fe2O3 is mainly concentrated around 645℃ (about 918K), which is much higher than the temperature of the foaming system. This ensures that the magnetic responsive fiber can be attracted by the magnetic field, and γ-Fe2O3 can be induced and heated by the alternating magnetic field, thereby initiating the second and third foaming of the first and second foaming agents. The response temperature of the second foaming agent is higher than that of the first foaming agent, and the response temperature of the first foaming agent is higher than that of the reaction system. Through the corresponding temperature difference between the first and second foaming agents, the synchronous response of the first and second foaming agents is avoided.

[0007] In addition, the present invention also discloses a preparation process for preparing the above-mentioned multi-color multi-density shoe sole, which includes the following steps; S1. Polymer particles and supercritical gas are mixed in a high-pressure reactor, allowing the supercritical gas to penetrate into the interior of the polymer particles. Then, the pressure is rapidly released to obtain foamed particles A. S2. The polymer particles of magnetic responsive fibers mixed with the second foaming agent, the first foaming agent and supercritical gas are mixed in a high-pressure reactor, so that the supercritical gas penetrates into the interior of the polymer particles, and then the pressure is quickly released to obtain foamed particles B. S3. Polymer particles containing a second foaming agent, photochromic material microparticles, magnetic responsive fibers, and supercritical gas are mixed in a high-pressure reactor, allowing the supercritical gas to penetrate into the interior of the polymer particles, and then the pressure is rapidly released to obtain foamed particles C. Steps S1 to S3 involve bead foaming using supercritical foaming technology, a process known to those skilled in the art. Since the specific process parameters are not described further, this will not lead to any ambiguity in the technical solution. Technical personnel can adjust the process according to production needs during implementation. S4. Foam beads A, B and C are placed into the preset part of the shoe sole mold, and water vapor is introduced to melt the surface of foam beads A, B and C. S5. An external local magnetic field is applied to attract and concentrate foam beads B and C at a preset location; S6. An externally applied alternating magnetic field is used to induction heat the magnetic response fiber, causing the first foaming agent in foamed bead B to respond and complete the second foaming. Then, the magnetic response fiber is induction heated to cause the second foaming agent to respond and complete the third foaming. S7. Cool the shoe sole mold and demold to obtain the multi-color, multi-density shoe sole.

[0008] As an improvement to the aforementioned technical solution: the supercritical gas is either CO2 or N2, CO 2、 Nitrogen (N2) is non-toxic, non-flammable, non-explosive, widely present in the air, and readily available, enabling excellent foaming effects at low cost.

[0009] Furthermore: In step S5, ultrasonic vibration is applied externally to the shoe sole mold. By contacting the transducer of the external ultrasonic vibration device with the shoe sole mold, ultrasonic vibration is applied to foam beads A, B, and C, which helps foam beads B and C to be attracted by the external magnetic field and concentrated in the magnetic field coverage area.

[0010] Furthermore, the shoe sole mold is made of non-metallic material, which can be high-strength industrial ceramics or high-temperature resistant epoxy resin. The purpose is to avoid the influence of metal materials on the shoe sole molding caused by magnetic fields or alternating magnetic fields. In specific implementation, technicians can also set a polytetrafluoroethylene anti-stick coating on the mold surface to reduce the adhesion between the shoe sole and the mold and facilitate demolding.

[0011] Furthermore: the photochromic material is specifically a diarylethylene polymer. When mixed with pigments, it not only changes color but also achieves a richer range of color changes than a single pigment / photochromic material. It exhibits excellent fatigue resistance, high contrast, and excellent high-temperature resistance. Under light, it induces an electrocyclization reaction, altering the conjugated molecular structure. The specific principle is as follows: The structure of diarylethene polymers includes a central olefin bridge (C=C) and aromatic heterocycles connecting the two ends of the central olefin bridge. In its natural state, the electrons within the molecule are not fully interconnected, therefore it does not absorb visible light and appears colorless and transparent. When irradiated with ultraviolet light of a specific wavelength (typically around 300 nm), the energy excites a concerted electrocyclization reaction in the aromatic rings at both ends of the central olefin bridge, similar to two rings rapidly closing like a snap fastener, forming a novel six-membered ring structure (closed ring). This new structure allows the entire molecule to form a large conjugated system, where electrons can flow freely over a wider range, thus increasing the absorption spectrum of the molecule from ultraviolet to... The outer region is significantly red-shifted into the visible light region, thereby absorbing light of a specific color, and macroscopically presenting a bright color (such as blue, red, etc.). The biggest difference from the color-developing principle of ordinary shoe soles is that existing supercritical foamed shoe soles use coatings to adhere to the surface of the sole to make the surface of the sole present patterns and color changes. Due to wear and tear from daily wear, the coating is easy to peel off and the sole fades. However, the composite shoe sole provided by this invention contains magnetically responsive fibers in the color-developing particles. Therefore, by applying an external magnetic field, the color-developing particles can be attracted to concentrate on the surface of the sole, so that the sole presents a preset color in a preset area. In addition, the pigment is evenly distributed in the color-developing particles and will not fade due to wear.

[0012] As can be seen from the above description of the structure of the present invention, compared with the prior art, the present invention has the following advantages: a. By combining physical foaming with chemical foaming, and under the influence of an external magnetic field, the sole exhibits regular density changes in different areas, which allows the sole to better fit the foot and improve wearing comfort; b. Based on the penetration of magnetic response fibers into adjacent foam beads, the combination with three-stage foaming can improve the bonding of adjacent foam beads, effectively solving the technical problem that existing bead foam soles are prone to tearing along the fusion interface and have low tear resistance. c. By controlling the concentration of color-developing microparticles on the sole surface through a magnetic field, the sole can display patterns and rich color variations. At the same time, the patterns and colors are highly integrated with the sole and are not easily damaged by wear on the sole surface. Attached Figure Description

[0013] The accompanying drawings, which form part of this application, are used to provide a further understanding of the invention. The illustrative embodiments of the invention and their descriptions are used to explain the invention and do not constitute an undue limitation of the invention. In the drawings: Figure 1 This is a schematic diagram of the front structure of the present invention (Example 1); Figure 2 This is a schematic diagram of the front structure of the present invention (Example 2); Figure 3 This is a schematic diagram of the magnetic response fiber connection structure; Figure 4 This is a schematic diagram of the side structure of the sole of the shoe according to the present invention; In the diagram: Foamed beads A-100, Foamed beads B-200, Foamed beads C-300. Detailed Implementation

[0014] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention. Example 1

[0015] Please see Figure 1 and Figure 3 This invention provides a multi-color, multi-density shoe sole, which is formed by molding foam beads A100, B200, and C300 using a shoe sole mold. Foam beads B200 are distributed in the forefoot area and the heel area of ​​the shoe sole, while foam beads C300 are distributed on the left and right sides of the shoe sole. Foam beads A100, B200, and C300 are prepared by foaming the same polymer. A first foaming agent is dispersed within foam beads B200, and color-developing microparticles are dispersed within foam beads C300. The color-developing microparticles are composed of a mixture of photochromic material and pigment. Magnetic responsive fibers are distributed within foam beads B200 and color-developing microparticles. The magnetic responsive fibers are composed of γ-Fe2O3 dispersed within PP fibers. A second foaming agent is distributed within the magnetic responsive fibers. The response temperature of the second foaming agent is higher than that of the first foaming agent, and the response temperature of the first foaming agent is higher than that of the reaction system temperature. Example 2

[0016] Please see Figure 2 and Figure 3 This invention provides a multi-color, multi-density shoe sole, which is formed by molding foam beads A100, B200, and C300 using a shoe sole mold. Foam beads B200 are distributed in the forefoot area, heel area, and arch area of ​​the shoe sole, while foam beads C300 are distributed on the left and right sides of the shoe sole. Foam beads A100, B200, and C300 are prepared by foaming the same polymer. A first foaming agent is dispersed within foam beads B200, and color-developing microparticles are dispersed within foam beads C300. The color-developing microparticles are composed of a mixture of photochromic material and pigment. Magnetic responsive fibers are distributed within foam beads B200 and color-developing microparticles. The magnetic responsive fibers are composed of γ-Fe2O3 dispersed within PP fibers. A second foaming agent is distributed within the magnetic responsive fibers. The response temperature of the second foaming agent is higher than that of the first foaming agent, and the response temperature of the first foaming agent is higher than that of the reaction system temperature.

[0017] Furthermore, this invention also discloses the preparation process of the multi-color, multi-density shoe soles of Examples 1 and 2, the preparation process of which includes the following steps: S1. TPU particles and supercritical CO2 gas are mixed in a high-pressure reactor (140℃, 25MPa) for 130 minutes to allow the supercritical gas to penetrate into the TPU particles. Then, the pressure is quickly released to obtain foamed particles A. S2. TPU particles containing magnetically responsive fibers mixed with a second foaming agent, a first foaming agent, and supercritical gas CO2 are mixed in a high-pressure reactor (140℃, 25MPa) for 130 minutes to allow the supercritical gas to penetrate into the interior of the TPU particles. Then, the pressure is quickly released to obtain foamed particles B. S3. TPU particles containing a second foaming agent, photochromic material microparticles, magnetically responsive fibers, and supercritical CO2 gas are mixed in a high-pressure reactor (140℃, 25MPa) for 130 minutes. The photochromic material is a diarylethylene polymer (particle size 80-140 micrometers). The supercritical gas is then allowed to penetrate into the interior of the TPU particles, and the mixture is then rapidly depressurized to obtain foamed particles C. S4. Foam beads A100, B200 and C300 are placed into a pre-set part of a non-metallic shoe sole mold, and water vapor is introduced to melt the surface of foam beads A100, B200 and C300. S5. An external local magnetic field (electromagnet or magnet can be used) is applied to attract and concentrate foam beads B200 and C300 at a preset position. During the process, ultrasonic vibration is applied to the shoe sole mold. S6. An externally applied alternating magnetic field is used to induction heat the magnetic response fiber, causing the first foaming agent in the foamed bead B200 to respond and complete the second foaming. Then, the magnetic response fiber is induction heated to cause the second foaming agent to respond and complete the third foaming. S7. Cool the shoe sole mold and demold to obtain the multi-color, multi-density shoe sole.

[0018] Working principle: In preparation step S5, foamed beads A100, B200, and C300 are placed into a predetermined position in the shoe sole mold. Subsequently, a local magnetic field is applied to the outside of the shoe sole mold (the coverage area of ​​the local magnetic field can be referenced). Figure 1 , Figure 2In the process of making foamed beads, the magnetic response fibers can be attracted by a magnetic field. Under the influence of the magnetic field, the magnetic response fibers can concentrate the foamed beads B200 and C300 in the magnetic field area, thereby achieving accurate distribution of the foamed beads in the shoe sole mold. Since the surfaces of foamed beads A100, B200 and C300 are melted in the preparation step S4, the flexibility of the magnetic response fibers located on the outside of the foamed beads is improved. Under the attraction of the magnetic field, the magnetic response fibers can be attracted to puncture the surface of adjacent beads. After the shoe sole cools and solidifies, the magnetic response fibers can connect adjacent foamed beads, which can improve the bonding strength between the foamed beads. This can solve the technical problem that existing beaded foamed shoe soles are prone to tearing and cracking along the bead fusion interface, and help improve the tear strength and overall toughness of beaded foamed shoe soles.

[0019] In preparation step S6, the first foaming agent is excited by the magnetic response fiber through alternating magnetic field induction heating, causing the foam beads B200 to complete secondary foaming. Due to the different foaming rates, a density difference is generated between the foam beads B200 and the foam beads A100. In Example 1, the foam beads B200 are concentrated in the forefoot and heel areas of the sole. These two areas are the main contact areas between the metatarsals and calcaneus and the sole. This distribution design aims to make the sole fit the metatarsals and calcaneus better during actual wear, thereby improving wearing comfort. In Example 2, the foam beads B200 are concentrated in the forefoot, heel, and arch areas of the sole. This distribution matches the force distribution of the foot on the sole, which helps to improve the fit of the sole to the foot.

[0020] After the second foaming in step S6 is completed, induction heating continues to raise the temperature and activate the second foaming agent, causing the magnetic response fiber to complete the third foaming. The third foaming can form cavities on the surface of the magnetic response fiber (see...). Figure 3 This cavity structure can improve the bonding between the magnetic response fiber and the bead, prevent the magnetic response fiber from detaching or peeling off from the bead, and help improve the tear strength and overall toughness of the sole.

[0021] In preparation step S5, under the influence of a local magnetic field, the foamed beads are concentrated at a predetermined location. The magnetically responsive fibers drive the photochromic microparticles to approach the magnetic field, thus concentrating them on the outer side of the sole, causing the sole surface to display patterns and colors. Without light, the photochromic microparticles exhibit pigment colors; with light, they exhibit a composite color of photochromic material and pigment (see...). Figure 4 This allows the sole to display a rich variety of colors. Furthermore, since the patterns and colors are not applied to the sole surface using paint spraying, even if the sole surface is worn, it will not affect the rich color variation.

[0022] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of this invention, "a plurality of" means two or more, unless otherwise explicitly specified.

[0023] In this invention, unless otherwise explicitly specified and limited, the terms "installation," "connection," "linking," and "fixing," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0024] Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions described in the foregoing embodiments or make equivalent substitutions for some of the technical features. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A multi-color, multi-density shoe sole, characterized in that: The sole is made by molding foam beads A (100), foam beads B (200) and foam beads C (300), which are prepared by foaming the same polymer. A first foaming agent is dispersed in foamed bead B (200), and color-developing microparticles are dispersed in foamed bead C (300). The color-developing microparticles are composed of a mixture of photochromic material and pigment. Magnetic response fibers are distributed in foamed bead B (200) and color-developing microparticles. The magnetic response fibers are composed of γ-Fe2O3 dispersed in PP fibers. A second foaming agent is distributed in the magnetic response fibers. The response temperature of the second foaming agent is greater than that of the first foaming agent, and the response temperature of the first foaming agent is greater than that of the reaction system temperature.

2. The multi-color, multi-density sole according to claim 1, characterized in that, Its preparation process includes the following steps: S1. Polymer particles and supercritical gas are mixed in a high-pressure reactor, allowing the supercritical gas to penetrate into the interior of the polymer particles. Then, the pressure is rapidly released to obtain foamed particles A. S2. The polymer particles of magnetic responsive fibers mixed with the second foaming agent, the first foaming agent and supercritical gas are mixed in a high-pressure reactor, so that the supercritical gas penetrates into the interior of the polymer particles, and then the pressure is quickly released to obtain foamed particles B. S3. Polymer particles containing a second foaming agent, photochromic material microparticles, magnetic responsive fibers, and supercritical gas are mixed in a high-pressure reactor, allowing the supercritical gas to penetrate into the interior of the polymer particles, and then the pressure is rapidly released to obtain foamed particles C. S4. Foamed beads A (100), foamed beads B (200) and foamed beads C (300) are placed into the preset part of the shoe sole mold, and water vapor is introduced to melt the surface of foamed beads A (100), foamed beads B (200) and foamed beads C (300); S5. An external local magnetic field is applied to attract and concentrate the foamed beads B (200) and C (300) at a predetermined location; S6. An externally applied alternating magnetic field is used to induce heating of the magnetic response fiber, causing the first foaming agent in the foamed bead B (200) to respond and complete the second foaming. Then, the magnetic response fiber is induced to heat the second foaming agent and complete the third foaming. S7. Cool the shoe sole mold and demold to obtain the multi-color, multi-density shoe sole.

3. The multi-color, multi-density shoe sole according to claim 2, characterized in that: The supercritical gas can be either CO2 or N2.

4. A multi-color, multi-density shoe sole according to claim 2, characterized in that: In step S5, ultrasonic vibration is applied externally to the shoe sole mold.

5. A multi-color, multi-density shoe sole according to claim 2, characterized in that: The shoe sole mold is made of non-metallic material.

6. A multi-color, multi-density shoe sole according to claim 2, characterized in that: The photochromic material is specifically a diarylethylene polymer.

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