KR-20260063688-A - Manufacturing method of eco-friendly shoe insoles containing castor oil

Abstract

The present invention relates to a method for manufacturing eco-friendly shoe insoles using castor oil. More specifically, the invention relates to a method for manufacturing eco-friendly shoe insoles using castor oil that can reduce carbon emissions and energy consumption through the use of eco-friendly materials and resource recycling. To this end, the present invention provides a method for producing an eco-friendly shoe insole using castor oil, comprising: a bio-polyurethane synthesis step (S100) of synthesizing bio-polyurethane by extracting polyol from castor oil; a cutting step (S200) of cutting the bio-polyurethane into a certain size; an adhesive application step (S300) of applying an adhesive to a specific surface of the bio-polyurethane; a fabric bonding step (S400) of bonding a fabric to the surface to which the adhesive is applied; an insole molding step (S500) of molding the bio-polyurethane bonded with the fabric into the shape of an insole by applying pressure using a press device; and a cutting step (S600) of cutting the bio-polyurethane molded into the shape of an insole according to the shape of the insole.

Inventors

• 이효

Assignees

• 주식회사 노바인터내쇼널

Dates

Publication Date

20260507

Application Date

20241031

Claims (3)

1. Biopolyurethane synthesis step (S100) of synthesizing biopolyurethane by extracting polyol from castor oil; A cutting step (S200) for cutting the biopolyurethane into a certain size; An adhesive application step (S300) of applying an adhesive to a specific surface of the biopolyurethane; A fabric bonding step (S400) for bonding a fabric to a surface coated with adhesive; An insole molding step (S500) in which bio-polyurethane with attached fabric is pressed using a press device to form it into the shape of an insole; A cutting step (S600) for cutting the bio-polyurethane molded into the shape of an insole according to the shape of the insole A method for producing eco-friendly shoe insoles using castor oil, including
2. In paragraph 1, The biopolyurethane synthesis step (S100) is Polyol extraction step for extracting polyols from castor oil, A mixing step (S120) of mixing polyol and diisocyanate in a 1:1 ratio, A catalyst addition step (S130) for adding a catalyst to promote foaming and curing of polyurethane, A molding and curing step (S140) in which the material is injected into a mold to form a desired shape and cured. A method for producing eco-friendly shoe insoles using castor oil, including further
3. In paragraph 2, The polyol extraction step is A bond structure conversion step in which peroxide or acetic acid is added to castor oil to convert the double bonds of castor oil into an epoxy bond structure, Hydroxyl amplification step in which glycol is added to epoxy castor oil to amplify the number of hydroxyl groups A method for producing eco-friendly shoe insoles using castor oil that further includes

Description

Manufacturing method of eco-friendly shoe insoles containing castor oil The present invention relates to a method for manufacturing eco-friendly shoe insoles using castor oil. More specifically, the invention relates to a method for manufacturing eco-friendly shoe insoles using castor oil that can reduce carbon emissions and energy consumption through the use of eco-friendly materials and resource recycling. Generally, various types of footwear, such as dress shoes, athletic shoes, and hiking boots, consist of an upper leather forming the exterior of the shoe, an outsole in contact with the ground, a midsole installed above the outsole, and an insole in contact with the sole of the foot (hereinafter referred to as "insole"). The insole is installed on the inner bottom surface of the shoe and is configured to cushion the impact force acting from the ground on the sole of the foot during walking, and to improve comfort and hygiene. Based on research findings indicating that foot health is a critical factor for the human body, various functions are being added to the aforementioned shoe insoles. For instance, many materials are being developed to form ergonomic structures capable of effectively absorbing shock, as well as to enhance sweat absorption, antibacterial properties, and deodorizing functions. Furthermore, technology has recently been proposed that incorporates heating elements to provide a warming function, thereby preventing frostbite during the winter season. Meanwhile, the above insoles are manufactured in the form of foam by foam molding materials such as polyurethane (PU), ethylene-vinyl acetate (EVA), polyethylene (PE), and latex, and are typically bonded to a fabric woven from natural or synthetic fibers using an adhesive or hot melt film. This bonding process has the advantage of reducing processing time and manpower compared to sewing processes by applying a liquid adhesive to the substrate and bonding the fabrics together after the solvent or moisture has evaporated through drying; however, to maximize cost savings, a process using thermoplastic hot-melt film and bonding the fabrics with a heat press is frequently applied instead of using liquid adhesive. The above-mentioned thermoplastic hot melt film is widely used in industrial fields such as footwear, clothing, and bags for purposes such as eco-friendly characteristics, convenience, and cost reduction. It can be manufactured from various types of thermoplastic resin films, including thermoplastic polyurethane (TPU), polyamide, ethylene vinyl acetate (EVA), and polyester. Since these thermoplastic hot melt films have good extrusion workability and high productivity, and are eco-friendly as they do not use solvents, selecting a material that has excellent adhesion and a good touch is suitable for ensuring adhesion to various fabrics. However, conventional thermoplastic hot melt films are typically manufactured with a thickness of 0.2 mm or more to ensure stable adhesion, so when a hot melt film is placed between fabrics and a press (No-Sew Press) is performed, overflow frequently occurs. Additionally, the fabric product becomes heavy overall and feels stiff to the touch, and it has the disadvantage of failing to meet the development trend of becoming increasingly lightweight. The problem with these conventional thermoplastic hot melt films is that they are thicker than 0.2 mm, but when a press is performed while they are inserted between a substrate and a fabric with different tissue densities, the amount of hot melt film is concentrated in the side with lower tissue density or the side with larger fabric weaving holes due to heat and pressure, resulting in no hot melt film being present at the adhesive interface and causing adhesion failure. This phenomenon is also the case with liquid adhesives. Therefore, there is an urgent need to develop a method for manufacturing insoles that can resolve these issues, enhance eco-friendliness, and provide the health benefits of castor oil. Prior Art: KR Registered Patent Publication No. 10-2324512 (Published Nov. 10, 2021) FIG. 1 is a drawing illustrating the manufacturing sequence of an eco-friendly shoe insole manufacturing method using castor oil according to a preferred embodiment of the present invention. FIG. 2 is a diagram illustrating the sequence of synthesizing polyurethane in the polyurethane synthesis step (S100). FIG. 3 is a diagram illustrating the extraction of polyols using castor oil. Figure 4 is a diagram illustrating the addition of glycol to epoxidized castor oil to amplify the number of hydroxyl groups. Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. First, it should be noted that in assigning reference numerals to the components of each drawing, the same components are given the same reference numeral whenever possible, even if they are shown in different drawings. Furthermore, in describing th