Method for manufacturing an insole and insole

Abstract

The application provides a preparation method of an insole and the insole. The preparation method of the insole comprises the following steps: a hot melt adhesive film of a surface cloth is arranged correspondingly to a base material; S1, the surface cloth and the base material are placed in a cavity of a mold for first molding, the cavity is communicated with the outside environment during the first molding, and the first molding is kept at a first temperature and for a first time; S2, the surface cloth and the base material are subjected to second molding, the second molding is kept at a second temperature and for a second time; S3, the surface cloth and the base material are subjected to third molding, the third molding is kept at a third temperature and for a third time; and S4, the surface cloth and the base material are subjected to fourth molding, the fourth molding is kept at a fourth temperature and for a fourth time, so that the insole is prepared; the pressure of the second molding is greater than that of the first molding, the third molding and the fourth molding, the pressure of the third molding is greater than that of the fourth molding, and the second temperature is greater than the first temperature, the third temperature and the fourth temperature. The insole can reduce the air bubbles, cavities, deformation and insufficient resilience of the insole to a certain extent.

Description

Technical Field

[0001] This invention relates to the field of insole technology, specifically to a method for preparing an insole and an insole itself. Background Technology

[0002] Ultra-thin insoles are increasingly becoming key components in high-end footwear due to their lightweight nature, conformability to the foot's contours, and excellent cushioning performance. Current technology involves bonding a fabric surface to a foamed, low-density thermoplastic elastomer substrate, followed by molding. However, insoles produced using this technology often suffer from defects such as air bubbles, voids, deformation, and insufficient resilience, affecting product strength, consistency, and resilience. Summary of the Invention

[0003] The purpose of this invention is to improve the above-mentioned defects of insoles in the prior art to a certain extent, and to provide a method for preparing an insole and an insole. Compared with the insoles in the prior art, this invention can reduce problems such as air bubbles, voids, deformation, and failure to meet preset requirements in the insole.

[0004] Through continuous observation, analysis, and experimentation, the applicant aims to identify the causes of the aforementioned problems in the insoles of the prior art. The applicant discovered that in the manufacturing process of ultra-thin insoles in the prior art, firstly, the foamed low-density thermoplastic elastomer substrate contains a large number of micropores containing air. During the molding process, the mold closes rapidly, quickly forming a sealed space in the cavity, preventing the effective expulsion of air from the micropores of the substrate, resulting in defects such as bubbles and voids in the insole. Secondly, during the molding process, continuous application of high pressure and temperature to the fabric and substrate causes the micropore structure of the substrate to collapse, damaging the micropore structure and thus reducing the insole's resilience. During the mold opening process, rapid depressurization from the high pressure allows air to quickly enter the micropore structure, causing instantaneous imbalance and collapse, further damaging the micropore structure and further reducing resilience. Thirdly, a certain amount of internal stress remains inside the molded insole. The prior art does not employ appropriate processes to release this internal stress after molding, leading to insole deformation.

[0005] The aforementioned defects in the background technology were first discovered by the applicant. Based on this, and in order to improve upon the defects in the background technology and achieve the purpose of this invention, the applicant adopts the following technical solution to solve the problem: A method for preparing an insole, using a surface fabric and a substrate, wherein the surface fabric is provided with a hot melt adhesive film, and the hot melt adhesive film of the surface fabric is correspondingly disposed with the substrate, comprising the following steps: S1. The face fabric and the substrate are placed in the cavity of the mold for the first molding. During the first molding, the cavity is connected to the external environment. The first molding is maintained at a first temperature and for a first time. S2. The face fabric and the substrate are subjected to a second molding process, and the second molding process is maintained at a second temperature and a second time. S3. The face fabric and the substrate are subjected to a third molding process, wherein the third molding process is maintained at a third temperature and a third time. S4. The fabric and the substrate are subjected to a fourth molding process, wherein the fourth molding process is maintained at a fourth temperature and a fourth time to prepare the insole. The pressure of the second molding is greater than the pressure of the first molding, the third molding, and the fourth molding, and the pressure of the third molding is greater than the pressure of the fourth molding; the second temperature is greater than the first temperature, the third temperature, and the fourth temperature.

[0006] Furthermore, by controlling the distance between the upper and lower molds of the mold, the volume of the cavity is adjusted, thereby adjusting the pressure of the first molding, the second molding, the third molding, and the fourth molding.

[0007] Furthermore, the substrate is PEBA material prepared by supercritical foaming.

[0008] Furthermore, in step S1, the pressure of the first molding is 2-3 MPa, the temperature is 80-100°C, and the time is 2-3 s; in step S2, the pressure of the second molding is 15-25 MPa, the temperature is 180-220°C, and the time is 15-30 s; in step S3, the pressure of the third molding is 8-12 MPa, the temperature is 100-120°C, and the time is 30-90 s; and in step S4, the pressure of the fourth molding is 1-2 MPa, the temperature is 90-110°C, and the time is 5-8 s.

[0009] Furthermore, the thickness of the face fabric is 0.5-1.5 mm, the thickness of the substrate is 2-5 mm, and the distance between the upper and lower molds in step S4 is 2-3 mm larger than the distance between the upper and lower molds in step S3; the density of the substrate is 0.12-0.20 g / cm³. 3 .

[0010] Furthermore, the edges of the insole are trimmed using ultrasonic cutting.

[0011] Furthermore, the preparation of the fabric includes the following steps: S100. The fabric is treated using plasma treatment technology. S200: Coat the fabric treated in step S100 with molten hot melt adhesive, and then cool it. S300: Cut the fabric cooled in step S200 to obtain the face fabric.

[0012] Furthermore, in step S100, the fabric is fed at a speed of 5-20 m / min using a plasma processor, the working gas pressure of the plasma processor is 0.3-0.6 MPa, and the discharge power is 1-5 kW. In step S200, within 3-8 seconds after the plasma treatment, the fabric is coated with molten hot melt adhesive at a temperature of 80-120°C and a pressure of 0.5-2 MPa.

[0013] Furthermore, the hot melt adhesive is EVA hot melt adhesive or TPU hot melt adhesive.

[0014] An insole comprising a face fabric and a substrate; the face fabric and the substrate are prepared by any one of the insole preparation methods described above.

[0015] As can be seen from the above description of the present invention, compared with the prior art, the present invention has the following beneficial effects: In the first technical solution, the fabric and substrate are placed inside the mold cavity, with the hot melt adhesive film of the fabric corresponding to the substrate and in direct contact. In step S1, the cavity is connected to the external environment during the first molding process. During this step, the microporous structure in the substrate is compressed, allowing air within the microporous structure to escape through the connection between the cavity and the external environment. Compared to existing technologies, this step prevents defects such as air bubbles and voids from forming in the insole. In step S2, the pressure and temperature of the second molding are both at their maximum values. During this step, the substrate softens, completing the formation of the insole's curvature, hardness, and surface texture. In step S3, the pressure of the third molding is lower than that of the second molding, and the third temperature is lower than that of the second temperature. This prevents the collapse of the microporous structure of the substrate due to continuous high pressure and high temperature, while allowing the substrate to initially solidify under controlled conditions. It also effectively prevents the microporous structure from being destroyed by rapid pressure release after high-pressure molding, ensuring cushioning and rebound performance. In step S4, the pressure of the third molding is greater than that of the fourth molding, allowing for the initial release of residual internal stress within the insole. Furthermore, the continued pressure prevents the insole from deforming uncontrollably during stress release. Compared to existing technologies, this solution can, to some extent, reduce issues such as air bubbles, voids, deformation, and failure to meet preset resilience requirements in insoles.

[0016] The second technical solution adjusts the cavity volume by controlling the distance between the upper and lower molds, thereby regulating the pressure of the first, second, third, and fourth molding processes. Decreasing the distance between the upper and lower molds reduces the cavity volume and increases the molding pressure; conversely, increasing the distance increases the cavity volume and decreases the molding pressure. In step S1, during the first molding process, the distance between the upper and lower molds allows the fabric and substrate to be subjected to molding pressure, while maintaining a gap between them to allow the cavity to communicate with the external environment. In step S2, by controlling the distance between the upper and lower molds to be less than that in step S1, the cavity volume is reduced, thereby adjusting the pressure of the second molding process to be greater than the pressure of the first molding process, and ensuring that the pressure of the second molding process is greater than the pressure of the third and fourth molding processes. In step S3, by controlling the distance between the upper and lower molds to be greater than the distance between the upper and lower molds in step S2, the volume of the cavity is increased, thereby adjusting the pressure of the second molding press to be greater than the pressure of the third molding press, meaning the pressure of the third molding press is less than the pressure of the second molding press. In step S4, by controlling the distance between the upper and lower molds to be greater than the distance between the upper and lower molds in step S3, the volume of the cavity is increased, thereby adjusting the pressure of the third molding press to be greater than the pressure of the fourth molding press, meaning the pressure of the fourth molding press is less than the pressure of the third molding press. The increased distance between the upper and lower molds in step S4 increases the cavity volume, allowing the residual internal stress inside the insole to be released, and allowing the insole to initially release stress within the confined space.

[0017] The third technical solution uses PEBA (polyether block amide) as the base material, which is produced by supercritical foaming. PEBA is a high-performance thermoplastic elastomer. The soft segments in its molecular structure provide elasticity, while the hard segments provide strength. The supercritical foaming process improves the resilience, lightweight, and durability of the insole.

[0018] The fourth technical solution further reduces problems such as air bubbles, voids, deformation, and failure to meet preset requirements in insoles by further limiting the temperature, pressure, and time in steps S1-S4.

[0019] The fifth technical solution utilizes a low-density, moderately thick base material combined with a thin outer fabric. This ensures both rebound and cushioning performance while achieving overall weight reduction in the insole, thus improving wearing comfort. By adjusting the outer fabric thickness to 0.5-1.5mm, the base material thickness to 2-5mm, and ensuring the spacing between the upper and lower molds in step S4 is 2-3mm larger than that in step S3, suitable space is provided for the release of internal stress, further preventing deformation of the insole due to stress release.

[0020] The sixth technical solution uses ultrasonic cutting to trim the edges, which, compared to the existing technology that uses heated blades, can prevent the edges of the insole from melting, deforming, or becoming deformed due to high temperatures.

[0021] The seventh technical solution involves treating the fabric with plasma treatment technology before applying the hot melt adhesive. Plasma treatment activates the fabric, enhancing its surface energy and allowing the hot melt adhesive to fully wet, spread, and penetrate the fiber surface, forming a dual bonding mechanism of physical anchoring and chemical bonding. This effectively prevents quality defects such as separation of the upper fabric from the substrate and glue failure during insole use.

[0022] The eighth technical solution involves ensuring the fabric adheres tightly to the hot melt adhesive at its highest surface energy state after activation, thereby improving the bonding strength between the hot melt adhesive and the fabric. Furthermore, by further restricting the fabric preparation process, the bonding strength between the fabric and the substrate is further enhanced.

[0023] The ninth technical solution improves the connection between the upper fabric and the substrate by limiting the use of hot melt adhesive, further avoiding quality defects such as separation of the upper fabric and the substrate or glue failure during the use of the insole.

[0024] The tenth technical solution is that the insole is made by any of the above-mentioned insole preparation methods. Compared with the prior art, this insole can reduce problems such as air bubbles, voids, deformation, and failure to meet the preset requirements of elasticity to a certain extent. Detailed Implementation

[0025] The technical solutions of the present invention will be clearly and completely described below with reference to the embodiments of the present invention. Obviously, the described embodiments are preferred embodiments of the present invention and should not be considered as excluding other embodiments. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative effort are within the scope of protection of the present invention.

[0026] Unless otherwise expressly defined, the use of terms such as "first," "second," or "third" in the claims and description of this invention is for distinguishing different objects, not for describing a specific order.

[0028] Unless otherwise expressly defined, the terms "fixed connection" or "fixed connection" used in the claims, description and contents of this invention shall be interpreted broadly to refer to any connection in which there is no displacement or relative rotation relationship between the two parties, that is, including non-removable fixed connection, detachable fixed connection, integral connection and fixed connection by other means or components.

[0029] In the claims and description of this invention, the terms "comprising," "having," and variations thereof are used to mean "including but not limited to."

[0030] Example 1 An insole includes a base material and a surface fabric laminated on the base material. The surface fabric is positioned corresponding to the foot area, and the surface fabric is laminated to the base material using a hot melt adhesive film. The base material has a thickness of 3 mm and a density of 0.16 g / cm³. 3 The fabric thickness is 1.0mm. The hot melt adhesive film is EVA hot melt adhesive film.

[0031] The preparation method of the insole includes the following steps: Step 1, Preparation of the face fabric, includes the following steps: S100. The raw material fabric is cut into rolls and treated using plasma treatment technology. The fabric is introduced into the plasma processor. During plasma treatment, the fabric feed speed is 10m / min, the working gas is compressed air, the working gas pressure of the plasma processor is 0.4MPa, the discharge power is 2.5kW, and the surface energy of the fabric increases from approximately 30 dyne / cm before treatment to 40 dyne / cm.

[0032] The S200 plasma-treated fabric enters the upper film composite roller within 5 seconds, aligning and overlapping the EVA hot melt adhesive with the activated fabric. The coating temperature of the upper film composite roller is 100℃ and the coating pressure is 1.0MPa, so that the molten hot melt adhesive can fully wet, spread and penetrate the surface of the activated fabric. The hot melt adhesive is then cooled and shaped by the cooling roller to form a hot melt adhesive film, and then it is wound up.

[0033] S300. The fabric after film treatment is fed into an electro-engraving device, and the corresponding outline is engraved according to the required size specifications. The shape and size of the fabric are then determined to obtain the face fabric.

[0034] Step Two S10. Cut the supercritical foamed PEBA material according to the size requirements to prepare the substrate, and the size of the substrate corresponds to the size of the fabric. S20. Position and hang the face fabric and the base material together. The hot melt adhesive film of the face fabric contacts the base material. The front and back, left and right sizes match one by one. The whole is flat and smooth, without misalignment, offset, or hollowness.

[0035] Step 3 S1. The face fabric and substrate are placed in the cavity of the mold for the first molding. The pressure of the first molding is 2.5 MPa, the first temperature is 90°C, and the first time is 2.5 s. During the first molding, the face fabric and substrate are subjected to the molding pressure of the mold. There is a gap between the parting surfaces of the upper and lower molds, so that the cavity is connected to the external environment. The first molding allows the air in the micropores of the substrate in the cavity to be discharged from the parting surface of the mold to the external environment.

[0036] S2. The fabric and substrate are subjected to a second molding process. After the first molding, the distance between the upper and lower molds is controlled to be less than the distance between the upper and lower molds in step S1, reducing the cavity volume. This allows the pressure of the second molding to be greater than the pressure of the first molding. The pressure of the second molding is 20 MPa, the second temperature is maintained at 200°C, and the second time is 20 seconds. The second molding fully softens the substrate and fills the mold cavity, completing the shaping of the insole's curvature, hardness, and surface texture.

[0037] S3. Perform a third molding process on the fabric and substrate. This third molding is performed after the second molding, by controlling the distance between the upper and lower molds to be greater than the distance between the upper and lower molds in step S2. This increases the volume of the cavity, thereby adjusting the pressure of the third molding to be less than the pressure of the second molding. The pressure of the third molding is 10 MPa, the temperature is maintained at 110°C, and the time is 60 seconds. This protects the internal microporous structure of the substrate and prevents the micropores from collapsing due to continuous high pressure and high temperature.

[0038] S4. The fabric and substrate are subjected to a fourth molding process. After the third molding, the distance between the upper and lower molds is controlled to be greater than the distance between the upper and lower molds in step S3, increasing the cavity volume. Therefore, the pressure of the fourth molding is less than the pressure of the third molding. The distance between the upper and lower molds in step S4 is 2.5 mm greater than the distance between the upper and lower molds in step S3. The pressure of the fourth molding is 1.5 MPa, the fourth temperature is maintained at 100°C, and the fourth time is 6 seconds. The insole is thus prepared.

[0039] Step Four The edges of the insoles, which retain residual heat, are trimmed using ultrasonic cutting, with the ultrasonic high-frequency vibrating cold cutter vibrating at a frequency of 24,000 times per minute. Then, they are sorted, inspected for defects such as glue separation, deformation, air bubbles, correct sizing, and clean appearance. Qualified insoles are then packaged and stored.

[0040] Example 2 The difference from Example 1 is as follows: In step S100, the fabric feeding speed is 8 m / min, the working gas is oxygen, the gas pressure is 0.5 MPa, the discharge power is 3.0 kW, and the surface energy of the treated fabric reaches 42 dyne / cm.

[0041] In step S200, the plasma-treated fabric enters the upper film composite roller within 4 seconds. The hot melt adhesive film is a TPU hot melt adhesive film. The coating temperature of the upper film composite roller is 110℃ and the coating pressure is 1.2MPa.

[0042] In step S1, the pressure of the first molding is 3MPa, the first temperature is 100℃, and the first time is 3s.

[0043] In step S2, the pressure of the second molding is 25 MPa, the temperature is 220°C, and the time is 25 s.

[0044] In step S3, the pressure of the third molding is 12 MPa, the temperature is 100℃, and the time is 80 s.

[0045] In step four, the ultrasonic high-frequency vibration cold cutting blade vibrates at a frequency of 30,000 times per minute.

[0046] Example 3 The difference between Example 3 and Example 1 is that: In step S100, the fabric feeding speed is 18 m / min, the gas pressure is 0.35 MPa, the discharge power is 4.0 kW, and the surface energy of the treated fabric reaches 38 dyne / cm.

[0047] In step S200, the hot melt adhesive film is a TPU hot melt adhesive film, the coating temperature of the upper film composite roller is 115℃, and the coating pressure is 0.8MPa.

[0048] In step S2, the pressure of the second molding is 18 MPa, the temperature is 190°C, and the time is 15 s.

[0049] In step S3, the pressure of the third molding is 9 MPa, the temperature is 115°C, and the time is 40 s.

[0050] In step four, the ultrasonic high-frequency vibration cold cutting blade vibrates at a frequency of 18,000 times per minute.

[0051] Example 4 The difference from Example 1 is as follows: The substrate thickness is 2mm and the density is 0.2g / cm³. 3 The fabric thickness is 0.5mm.

[0052] In step S1, the pressure of the first molding is 2MPa, the first temperature is 80℃, and the first time is 2s.

[0053] In step S2, the pressure of the second molding is 15 MPa, the temperature is 180°C, and the time is 15 s.

[0054] In step S3, the pressure of the third molding is 8 MPa, the temperature is 120°C, and the time is 30 seconds.

[0055] Example 5 The difference from Example 1 is as follows: The substrate thickness is 5mm and the density is 0.12g / cm³. 3 The fabric thickness is 1.5mm.

[0056] In step S1, the pressure of the first molding is 3MPa, the first temperature is 100℃, and the first time is 3s.

[0057] In step S2, the pressure of the second molding is 25 MPa, the temperature is 220°C, and the time is 30 s.

[0058] In step S3, the pressure of the third molding is 12 MPa, the temperature is 100℃, and the time is 90 s.

[0059] Comparative Example Step 1, Preparation of the face fabric, includes the following steps: A100. Cut the entire roll of raw fabric into pieces.

[0060] A200: The fabric is fed into the upper film laminating roller, and the EVA hot melt adhesive film is aligned and overlapped with the fabric. The coating temperature of the upper film laminating roller is 100℃, the coating pressure is 1.0MPa, and then the fabric is cooled and shaped by the cooling roller before being wound up.

[0061] A300. The fabric after film treatment is fed into the cutting equipment and cut out the corresponding outline according to the required size specifications to prepare the face fabric.

[0062] Step Two A10. Cut the foamed TPF material according to the size requirements to prepare the base material, and the size of the base material corresponds to the size of the face fabric. A20. Manually position the fabric and the substrate.

[0063] Step 3 A1. Place the fabric and substrate into the mold cavity. After the mold is closed, the molding pressure is 15MPa, the mold temperature is 200℃, and the duration is 60s. This softens the TPF material and fills the mold cavity, completing the shaping of the insole's curvature and surface texture.

[0064] A2. Turn off the heating power and open the exhaust valve to quickly depressurize the internal pressure of the mold from 15MPa to atmospheric pressure (0.1MPa) in one go. The depressurization time is about 2-3 seconds. While depressurizing, the mold remains closed and the surface temperature of the product drops to about 80°C by natural cooling to obtain the insole.

[0065] Step Four The edges of the insoles are cut and trimmed using heated cutting tools, and then sorted to ensure they are free of glue separation, deformation, air bubbles, and are of standard size and clean appearance. Qualified insoles are then packaged and put into storage.

[0066] The insoles prepared in Examples 1-5 and the comparative examples were subjected to performance tests. The test results are shown in Table 1. The bubble defect rate was determined by visual inspection. The finished insoles were placed under a standard light source (illuminance not less than 1000 lx), and inspectors checked the surface and interior of each insole for visible bubbles (closed bubble defects with a diameter ≥ 0.5 mm). The bubble defect rate was calculated using the following formula: Bubble defect rate = (number of insoles with bubble defects / total number of insoles inspected) × 100%. The demolding warpage rate was determined by the plate measurement method. The finished insoles were placed on a standard horizontal platform, and the maximum gap between the bottom of the insole and the platform was measured. A maximum gap exceeding 1.0 mm is considered warping deformation, and the demolding warping deformation rate is calculated using the following formula: Demolding warping deformation rate = (Number of insoles with warping deformation / Total number of insoles inspected) × 100%; The peel strength between the upper fabric and the sole material is determined according to GB / T 3903.8-2022 "Test Methods for Insoles of Footwear - Interlayer Peel Strength"; The resilience rate is determined according to GB / T6670-2008 "Determination of Rebound Performance of Flexible Foam Polymer Materials by Falling Ball Method"; The compression set is determined according to GB / T6669-2008 "Determination of Compression Set of Flexible Foam Polymer Materials".

[0067] Table 1 Performance Test Table

[0068] As shown in the table above, the bubble defect rate is less than 0.2% and the demolding warpage rate is less than 0.5%, both significantly better than the comparative examples. Example 2, using oxygen plasma treatment and TPU hot melt adhesive film, achieved a peel strength of 11.5 N / cm and a resilience of 75%, making it the best example. Examples 1-5 showed no delamination defects between the fabric and the substrate, while the comparative examples exhibited obvious problems such as bubbles and warpage.

[0069] In this embodiment, the fabric and substrate are placed inside the mold cavity, with the hot melt adhesive film of the fabric corresponding to the substrate and in direct contact with it. In step S1, the cavity is connected to the external environment during the first molding process. During this step, the microporous structure in the substrate is compressed, allowing air within the microporous structure to escape through the connection between the cavity and the external environment. Compared to existing technologies, this step prevents defects such as bubbles and voids from forming in the insole. In step S2, the pressure and temperature of the second molding are both at their maximum values. During this step, the substrate softens, completing the formation of the insole's curvature, hardness, and surface texture. In step S3, the pressure of the third molding is lower than that of the second molding, and the third temperature is lower than that of the second temperature. This prevents the continuous high pressure and high temperature from causing the microporous structure of the substrate to collapse. Simultaneously, it allows the substrate to initially solidify under controlled conditions and effectively prevents rapid pressure release after high-pressure molding, which could damage the microporous structure and ensure cushioning and rebound performance. In step S4, the pressure of the third molding is greater than that of the fourth molding, allowing for the initial release of residual internal stress within the insole. Furthermore, the continued pressure prevents the insole from deforming uncontrollably during stress release. Compared to existing technologies, this embodiment can, to a certain extent, reduce issues such as air bubbles, voids, deformation, and failure to meet preset resilience requirements in the insole.

[0070] In this embodiment, the volume of the cavity is adjusted by controlling the distance between the upper and lower molds, thereby adjusting the pressure of the first, second, third, and fourth molding processes. Decreasing the distance between the upper and lower molds reduces the cavity volume and increases the molding pressure; conversely, increasing the distance increases the cavity volume and decreases the molding pressure. In step S1, during the first molding process, the distance between the upper and lower molds allows the fabric and substrate to be subjected to molding pressure, while maintaining a gap between them to allow the cavity to communicate with the external environment. In step S2, by controlling the distance between the upper and lower molds to be less than the distance in step S1, the cavity volume is reduced, thereby adjusting the pressure of the second molding process to be greater than the pressure of the first molding process, and ensuring that the pressure of the second molding process is greater than the pressure of the third and fourth molding processes. In step S3, by controlling the distance between the upper and lower molds to be greater than the distance between the upper and lower molds in step S2, the volume of the cavity is increased, thereby adjusting the pressure of the second molding press to be greater than the pressure of the third molding press, meaning the pressure of the third molding press is less than the pressure of the second molding press. In step S4, by controlling the distance between the upper and lower molds to be greater than the distance between the upper and lower molds in step S3, the volume of the cavity is increased, thereby adjusting the pressure of the third molding press to be greater than the pressure of the fourth molding press, meaning the pressure of the fourth molding press is less than the pressure of the third molding press. The increased distance between the upper and lower molds in step S4 increases the cavity volume, allowing the residual internal stress inside the insole to be released, and allowing the insole to initially release stress within the confined space.

[0071] In this embodiment, the substrate is PEBA obtained through supercritical foaming. PEBA (polyether block amide) is a high-performance thermoplastic elastomer. The soft segments in its molecular structure provide elasticity, and the hard segments provide strength. The substrate is obtained through supercritical foaming, which improves the resilience, lightweight and durability of the insole.

[0072] In this embodiment, by further limiting the temperature, pressure and time in steps S1-S4, problems such as air bubbles, voids, deformation and failure to meet preset requirements in the insole are further reduced.

[0073] In this embodiment, by using a substrate with low density and moderate thickness, combined with a thin outer fabric, the overall weight of the insole is reduced while ensuring rebound and cushioning performance, thus improving wearing comfort. The corresponding settings—0.5-1.5mm for the outer fabric thickness, 2-5mm for the substrate thickness, and a 2-3mm larger gap between the upper and lower molds in step S4 compared to step S3—provide suitable space for the release of internal stress, further preventing the insole from deforming due to the release of internal stress.

[0074] In this embodiment, ultrasonic cutting is used to trim the edges, which, compared to the existing technology that uses heated blades, can prevent the edges of the insole from being melted, deformed, or altered by high temperatures.

[0075] In this embodiment, the fabric is treated with plasma technology before applying the hot melt adhesive. Plasma treatment activates the fabric, increasing its surface energy. This allows the hot melt adhesive to fully wet, spread, and penetrate the fiber surface of the activated fabric, forming a dual bonding mechanism of physical anchoring and chemical bonding. This effectively prevents quality defects such as separation of the upper fabric from the substrate and glue failure during the use of the insole.

[0076] In this embodiment, the hot melt adhesive is tightly bonded to the fabric when the surface energy is at its highest after activation, thus improving the bonding strength between the hot melt adhesive and the fabric. Furthermore, by further restricting the fabric preparation process, the bonding strength between the fabric and the substrate is further improved.

[0077] In this embodiment, the bonding effect between the upper fabric and the substrate is improved by limiting the use of hot melt adhesive, which further avoids quality defects such as separation of the upper fabric and the substrate or glue failure during the use of the insole.

[0078] In this embodiment, the insole is prepared using any of the above-mentioned insole preparation methods. Compared with the prior art, this insole can reduce problems such as air bubbles, voids, deformation, and failure to meet preset requirements in the insole to a certain extent.

[0079] The foregoing description of the specifications and embodiments is intended to explain the scope of protection of this invention, but does not constitute a limitation on the scope of protection of this invention. Modifications, equivalent substitutions, or other improvements to the embodiments of this invention or a portion thereof that can be obtained by those skilled in the art through logical analysis, reasoning, or limited experimentation, based on the teachings of this invention or the foregoing embodiments, in conjunction with common knowledge, general technical knowledge, and / or existing technology, should all be included within the scope of protection of this invention.

Claims

1. A method for preparing an insole, characterized in that, Using a face fabric and a substrate, wherein the face fabric is provided with a hot melt adhesive film, and the hot melt adhesive film of the face fabric is correspondingly disposed with the substrate, the method includes the following steps: S1. The face fabric and the substrate are placed in the cavity of the mold for the first molding. During the first molding, the cavity is connected to the external environment. The first molding is maintained at a first temperature and for a first time. S2. The face fabric and the substrate are subjected to a second molding process, and the second molding process is maintained at a second temperature and a second time. S3. The face fabric and the substrate are subjected to a third molding process, wherein the third molding process is maintained at a third temperature and a third time. S4. The fabric and the substrate are subjected to a fourth molding process, wherein the fourth molding process is maintained at a fourth temperature and a fourth time to prepare the insole. The pressure of the second molding is greater than the pressure of the first molding, the third molding, and the fourth molding, and the pressure of the third molding is greater than the pressure of the fourth molding; the second temperature is greater than the first temperature, the third temperature, and the fourth temperature.

2. The method for preparing an insole as described in claim 1, characterized in that, The volume of the cavity is adjusted by controlling the distance between the upper and lower molds of the mold, thereby adjusting the pressure of the first molding, the second molding, the third molding, and the fourth molding.

3. The method for preparing an insole as described in claim 2, characterized in that, The substrate is made of PEBA material through supercritical foaming.

4. The method for preparing an insole as described in claim 3, characterized in that, In step S1, the pressure of the first molding is 2-3 MPa, the temperature is 80-100°C, and the time is 2-3 s; in step S2, the pressure of the second molding is 15-25 MPa, the temperature is 180-220°C, and the time is 15-30 s; in step S3, the pressure of the third molding is 8-12 MPa, the temperature is 100-120°C, and the time is 30-90 s; in step S4, the pressure of the fourth molding is 1-2 MPa, the temperature is 90-110°C, and the time is 5-8 s.

5. The method for preparing an insole as described in claim 4, characterized in that, The thickness of the face fabric is 0.5-1.5 mm, the thickness of the substrate is 2-5 mm, and the distance between the upper and lower molds in step S4 is 2-3 mm larger than the distance between the upper and lower molds in step S3; the density of the substrate is 0.12-0.20 g / cm³. 3 .

6. The method for preparing an insole as described in claim 1, characterized in that, The edges of the insole are trimmed using ultrasonic cutting.

7. A method for preparing an insole according to any one of claims 1-5, characterized in that, The preparation of the fabric includes the following steps: S100. The fabric is treated using plasma treatment technology. S200: Coat the fabric treated in step S100 with molten hot melt adhesive, and then cool it. S300: Cut the fabric cooled in step S200 to obtain the face fabric.

8. The method for preparing an insole as described in claim 7, characterized in that, In step S100, the fabric is fed at a speed of 5-20 m / min using a plasma processor, the working gas pressure of the plasma processor is 0.3-0.6 MPa, and the discharge power is 1-5 kW. In step S200, within 3-8 seconds after plasma treatment, the fabric is coated with molten hot melt adhesive at a temperature of 80-120°C and a pressure of 0.5-2 MPa.

9. The method for preparing an insole as described in claim 7, characterized in that, The hot melt adhesive is EVA hot melt adhesive or TPU hot melt adhesive.

10. An insole, characterized in that, It includes a face fabric and a substrate; the face fabric and the substrate are prepared by the insole preparation method according to any one of claims 1-9.

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