Shoe insole with antimicrobial properties and method of manufacturing the same

Abstract

A method of manufacturing a shoe insole with antimicrobial properties is disclosed. A foam base material is provided. The foam material is heated and a compressive force is applied to shape the foam material to approximately 60-75 percent of its final form dimensions. One or more antimicrobial agents is introduced into the foam material at levels from 1% to 5% by weight of the polyurethane foam while the heat and compressive force are maintained, to ensure thorough integration and uniform distribution of the one or more antimicrobial agents through the foam material, until the foam material reaches its final form. A fabric material is adhered or bonded to the final foam material to create a unified insole structure. The foam base material may be an open-cell, polyurethane foam base material.

Description

CROSS-REFERENCE TO RELATED APPLICATIONS

[0001] This application claims priority under 35 USC § 119(e) of U.S. Provisional Application Ser. No. 63 / 775,073, filed on Mar. 20, 2025, and entitled “SHOE INSOLE WITH ANTIMICROBIAL PROPERTIES AND METHOD OF MANUFACTURING THE SAME,” the entire disclosure of which is incorporated herein by reference.TECHNICAL FIELD

[0002] The present invention is generally directed to a shoe insole, and more particularly to a shoe insole with antimicrobial properties.BACKGROUND OF THE INVENTION

[0003] Insoles are provided on the bottom surface of the shoe in order to provide a cushioning force to the foot portion when the shoe is worn, minimizing stress on the joints and reducing the risk of injury, and to absorb moisture such as sweat discharged through the foot when walking or running.

[0004] However, due to the structural characteristics of the shoe that covers the entire foot, the foot inside the shoe is inevitably blocked from the outside air. Prolonged use of footwear and lack of release for secreted bodily fluids like perspiration from the user's foot may result in an unhygienic environment due to microbial growth within the confined spaces of the shoe, generating foul odors and causing diseases such as athlete's foot.

[0005] What is needed is complete integration of a bio-based antimicrobial agent through a multi-layered shoe insole, creating a unified insole structure that offers enhanced cushioning. moisture management, and comprehensive odor management for prolonged use and athletic performance.SUMMARY OF THE INVENTION

[0006] In accordance with one embodiment of the present invention, a method of manufacturing a shoe insole with antimicrobial properties is disclosed. The method includes providing a foam base material. The method also includes heating the foam material while applying a compressive force to shape the foam material to approximately 60-75 percent of its final foam dimensions. The method further includes introducing one or more antimicrobial agents into the foam material at levels from 1% to 5% by weight of the polyurethane foam while the heat and compressive force are maintained until the foam material reaches its final form. This is to ensure thorough integration and uniform distribution of the one or more antimicrobial agents through the foam material. The method also includes adhering or bonding a fabric material to the final foam material to create a unified insole structure.

[0007] The foam material may be heated at a temperature range ween about 65 ° F to about 75 ° F. In some embodiments, the foam material is heated at a temperature range between about 68 ° F to about 72 ° F. The foam base material may be an open-cell, polyurethane foam base material.

[0008] In some embodiments, heating the foam material while applying the compressive force shapes the foam material to approximately 65-70 percent of its final form dimensions.

[0009] The one or more antimicrobial agents may be, but are not limited to, guava, neem, and mixtures thereof.

[0010] In some embodiments, the antimicrobial agents are up to 3% by weight of the polyurethane foam.

[0011] The fabric material may include, but is not limited to, a polymer or natural fiber.

[0012] In another embodiment of the present invention, a shoe insole with antimicrobial properties is disclosed. The insole includes a top fabric layer and a bottom cushioning layer. The cushioning layer is a foam base material. The foam material is treated with one or more antimicrobial agents at levels from 1% to 5% by weight of the polyurethane foam. The foam material is treated with the one or more antimicrobial agents as the foam material reaches approximately 60-75 percent of its final form dimensions by application of heat and a compressive force. A fabric layer is adhered or bonded to the final foam material to create a unified insole structure.

[0013] In some embodiments, the foam material is treated with the one or more antimicrobial agents as the foam material reaches approximately 65-70 percent of its final form dimensions by application of heat and a compressive force. The heat and compressive force are maintained until the foam material reaches its final form, which ensures thorough integration and uniform distribution of the one or more antimicrobial agents through the foam material. The foam base material may be an open-cell, polyurethane foam base material.BRIEF DESCRIPTION OF THE DRAWINGS

[0014] FIG. 1 is a perspective view of a shoe insole with antimicrobial properties, in accordance with one embodiment of the present invention.

[0015] FIG. 2 is a flowchart representation of an example method of manufacturing a shoe insole with antimicrobial properties, in accordance with one embodiment of the present invention.DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0016] FIG. 1 is a perspective view of a shoe insole with antimicrobial properties, in accordance with one embodiment of the present invention. The shoe insole includes a foam or footbed base material 20 covered by a cushioning layer 25, which may be an open cell, polyurethane foam base material. The cushioning layer 25 is treated with one or more antimicrobial agents at levels from 1% to 5% by weight of the polyurethane foam. A fabric layer 30 is bonded (or adhered) to the antimicrobial treated polyurethane foam material to create a unified insole structure.

[0017] The foam base material 20 may be treated with the one or more antimicrobial agents as the foam material 20 reaches approximately 60-75 percent of its final form dimensions by application of heat and a compressive force. In some embodiments, the foam material 20 is treated with the one or more antimicrobial agents as the foam material 20 reaches approximately 65-70 percent of its final form dimensions by application of heat and a compressive force.

[0018] The heat and compressive force are maintained until the foam material 20 reaches its final form, which ensures thorough integration and uniform distribution of the one or more antimicrobial agents through the foam material 20.

[0019] The foam base material 20 may be heated at a temperature range between about 65 F to about 75 °F. In some embodiments, the foam base material 20 may be heated at a temperature range between about 68 °F to about 72 ° F.

[0020] It should be noted that the insole is not limited to three layers. For example, the insole may comprise fewer than two layers and, in some embodiments, more than three layers. As one example, the insole may include a top fabric layer and a bottom cushioning layer, as a two-layer insole.

[0021] FIG. 2 is a flowchart 100 representation of an example method of manufacturing a shoe insole with antimicrobial properties, in accordance with one embodiment of the present invention.

[0022] In step 110, a foam base material is provided. In some embodiments, the foam base material is an open-cell polyurethane material. The foam material is heated while a compressive force is applied to shape the foam material to approximately 60-75 percent of its final form dimensions, as shown in step 120. The heat and compressive force in step 120 may be applied to shape the foam material to approximately 65-70 percent of its final form dimensions.

[0023] In step 130, one or more antimicrobial agents is introduced into the foam material at levels from 1% to 5% by weight of the polyurethane foam while the heat and compressive are maintained. In some embodiments, the one or more antimicrobial agents may be introduced into the foam material at approximately 3% by weight of the polyurethane foam or, alternatively, up to 3% by weight of the polyurethane foam, while the heat and compressive force are maintained.

[0024] Heat and compressive force are maintained in step 140 to ensure thorough and uniform distribution of the one or more antimicrobial agents through the foam material until the foam material reaches its final form.

[0025] A fabric material is adhered or bonded to the final foam material, in step 150, to create a unified insole structure. The fabric material may comprise a polymer or natural fiber, but it should be understood that other materials may be used for the fabric material.

[0026] In another embodiment of the present invention, a method of manufacturing a three-dimensional composite insole structure engineered to optimize wearer comfort and foot microenvironment management is disclosed. The process in this specific embodiment involves the following sequential method of insole construction:Step 1: Preparation of Polyurethane Foam

[0027] Initially, a high-performance open-cell polyurethane foam base is prepared at a controlled temperature of 70±2 degrees Fahrenheit. During this stage, a compressive pressure force is applied to the material. Thus, the material is heated while applying the compressive force to ensure proper shaping and density. The specific pressure applied is tailored to achieve the desired foam characteristics, although exact figures may vary based on equipment and material specifications.Step 2: Introduction of Antimicrobial Powder

[0028] At a critical stage of the manufacturing process, specifically during the initial compression phase when the foam matrix reaches approximately 65-70% of its final form, 1% to 5% by weight (e.g. 3% by weight) of a specialized bio-based antimicrobial powder is methodically introduced. As such, the antimicrobial material is applied while the compressive force and heat are maintained to ensure thorough integration and uniform distribution. This process targets the elimination of volatile organic compounds (VOCs) and bacterial metabolites responsible for malodorous compounds in athletic footwear.Step 3: Final Compression and Molding

[0029] Following the introduction of the antimicrobial powder, the final compression and molding stages are carried out. This is a continuation of the compressive force and heating, described in the previous step, until the foam material reaches its final form. The top fabric layer is typically added during this stage, where it is bonded to the foam layer to create a seamless structure. The foam matrix refers to the interconnected network of foam cells that provide structural integrity and cushioning.Step 4; Creating a Unified Insole Structure

[0030] The process culminates in creating a unified insole structure, which is the integration of the foam material with the antimicrobial agent and the top fabric layer, resulting in enhanced cushioning, moisture management, and comprehensive odor neutralization for prolonged athletic performance.

[0031] The embodiments of the present invention provides benefits over the prior art in areas of hygiene, comfort, and practicality. The shoe insole with antimicrobial properties integrated therein is designed with hygiene, comfort, and performance in mind, to keep the shoe insole free from odors and bacteria buildup during activity while providing comfort and structural integrity.

[0032] By strategically addressing the biochemical origins of foot odor—primarily deriving from bacterial breakdown of skin lipids and sweat proteins—the insole provides a scientifically advanced solution to foot microbiome management. The antimicrobial properties specifically target gram-positive and gram-negative bacteria responsible for producing trimethylamine, isovaleric acid, and other odoriferous compounds, effectively mitigating the complex olfactory challenges inherent in intense athletic use.

[0033] The present invention has been described in terms of specific embodiments incorporating details to facilitate the understanding of the principles of construction and operation of the invention. As such, references herein to specific embodiments and details thereof are not intended to limit the scope of the claims appended hereto. It will be apparent to those skilled in the art that modifications can be made in the embodiments chosen for illustration without departing from the spirit and scope of the invention.

Claims

1. A method of manufacturing a shoe insole with antimicrobial properties, comprising:a. providing a foam base material;b. heating the foam material while applying a compressive force to shape the foam material to approximately 60-75 percent of its final form dimensions;c. introducing one or more antimicrobial agents into the foam material at levels from 1% to 5% by weight of the polyurethane foam while the heat and compressive force are maintained, to ensure thorough integration and uniform distribution of the one or more antimicrobial agents through the foam material, until the foam material reaches its final form; andd. adhering or bonding a fabric material to the final foam material to create a unified insole structure.

2. The method of claim 1 wherein the foam base material is an open-cell polyurethane foam base material.

3. The method of claim 2 wherein the foam material is heated at a temperature range between approximately 65 °F to approximately 75 ° F.

4. The method of claim 3 wherein the foam material is heated at a temperature range between 68 ° F to 72 ° F.

5. The method of claim 4 wherein heating the foam material while applying the compressive force shapes the foam material to approximately 65-70 percent of its final form dimensions.

6. The method of claim 5 wherein the one or more antimicrobial agents are guava, neem, or mixtures thereof.

7. The method of claim 6 wherein the antimicrobial agents are approximately 3% by weight of the polyurethane foam.

8. The method of claim 7 wherein the fabric material comprises at least one of a polymer or natural fiber9. A shoe insole with antimicrobial properties, comprising:a. a top layer including a fabric layer; andb. a bottom layer including at least one cushioning layer, wherein the cushioning layer is a foam base material, wherein the foam material is treated with one or more antimicrobial agents at levels from 1% to 5% by weight of the polyurethane foam.

10. The shoe insole of claim 9 wherein the foam base material is an open-cell polyurethane foam base material.

11. The shoe insole of claim 10 wherein the foam material is treated with the one or more antimicrobial agents as the foam material reaches approximately 60-75 percent of its final form dimensions by application of heat and a compressive force12. The shoe insole of claim 11 wherein the foam material is treated with the one or more antimicrobial agents as the foam material reaches approximately 65-70 percent of its final form dimensions by application o compressive force.

13. The shoe insole of claim 12 wherein the heat and compressive force are maintained until the foam material reaches its final form, which ensures thorough integration and uniform distribution of the one or more antimicrobial agents through the foam material.

14. The shoe insole of claim 13 wherein the fabric layer is adhered or bonded to the final foam material to create a unified insole structure.

15. The shoe insole of claim 14 wherein the foam material is heated at a temperature range between approximately 65 ° F to approximately 75 ° F.

16. The shoe insole of claim 13 wherein the foam material is heated at a temperature range between about 68 ° F to about 72 ° F.

17. The shoe insole of claim 16 wherein the one or more antimicrobial agents are guava, neem, or mixtures thereof.

18. The shoe insole of claim 17 wherein the one or more antimicrobial agents are approximately 3% by weight of the polyurethane foam.

19. The shoe insole of claim 18 wherein the fabric material comprises at least one of a polymer or natural fiber.

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