A three-layer composite shoe sole without adhesive

Abstract

This utility model relates to the field of shoe sole technology, specifically disclosing a glue-free three-layer composite shoe sole and its manufacturing method, comprising an insole, a midsole, and an outsole stacked sequentially from top to bottom; the insole is composed of thermoplastic polyurethane elastomer beads to maintain the arch support shape of the sole; the midsole is composed of polyurethane material; the outsole is composed of polyurethane foam material for wear resistance; the density of the outsole is greater than that of the midsole, and the volume of the outsole is smaller than the sum of the volumes of the other parts of the sole; the midsole is directly bonded to both the insole and the outsole without adhesive. This utility model, through the glue-free composite of three layers of materials with different properties, allows each layer to complement each other's advantages: the outsole provides wear resistance, the midsole provides lightweight support, and the insole provides softness and comfort. The entire structure requires no adhesive, avoiding delamination and contamination, while simultaneously achieving a synergistic effect of lightweight, comfort, and wear resistance.

Description

Technical Field

[0001] This utility model relates to the field of shoe sole technology, and in particular to a three-layer composite shoe sole that does not require adhesive bonding. Background Technology

[0002] The sole is the core component of footwear that directly bears the weight of the human body, contacts the ground, and affects wearing comfort. To meet different functional needs, current soles are typically designed with a multi-layered structure, such as consisting of three layers: the outsole (contacts the ground, providing abrasion resistance and slip resistance), the midsole (provides cushioning and support), and the insole (contacts the sole of the foot, providing softness and comfort). The performance requirements for materials differ significantly between the different layers: the outsole needs high abrasion resistance and high slip resistance, the midsole needs to be lightweight, highly resilient, and provide good support, and the insole needs to be soft, breathable, and conform to the body.

[0003] However, a single material often cannot simultaneously meet the requirements of multiple properties mentioned above. For example, traditional rubber outsoles are wear-resistant but have a high density and are heavy; polyurethane (PU) midsoles are lightweight but lack wear resistance; and ordinary foam insoles are soft but lack support. To combine materials with different properties into one piece, current technologies generally use adhesives for interlayer bonding. However, adhesives have many drawbacks: first, the adhesive contains volatile organic compounds such as formaldehyde, which are not environmentally friendly and are harmful to health; second, the adhesive layer is prone to aging and delamination under long-term use or in humid environments, leading to sole delamination, cracking, and a shortened lifespan; third, the adhesive application process increases production costs and process complexity, and the adhesive layer itself changes the weight and rigidity of the sole, weakening the lightweight and comfortable effect. Utility Model Content

[0004] In view of this, the purpose of this utility model is to propose a glue-free three-layer composite sole to solve the problems of existing three-layer soles being prone to delamination and environmentally unfriendly due to the use of adhesives, and the difficulty of achieving wear resistance, lightness and comfort in a single layer material.

[0005] To achieve the above objectives, this utility model provides a glue-free three-layer composite sole, comprising, from top to bottom, layers of:

[0006] The insole is made of thermoplastic polyurethane elastomer beads and is used to maintain the arch support shape of the shoe sole.

[0007] The midsole is made of polyurethane foam.

[0008] The outsole is molded from polyurethane material for wear resistance;

[0009] The density of the outsole is greater than that of the midsole, and the volume of the outsole is less than the sum of the volumes of the other parts of the sole. The midsole is directly bonded to the insole and the outsole without any adhesive.

[0010] Furthermore, the density of the inner bottom is 0.08 g / cm³.

[0011] Furthermore, the foaming temperature of the midsole is 45℃-55℃, and the molding temperature is 60℃-65℃.

[0012] A method for preparing a glue-free three-layer composite shoe sole, used in the production of the aforementioned glue-free three-layer composite shoe sole, includes the following steps:

[0013] First, the polyurethane material for the outsole is injected into the mold and pre-cured to obtain a thin layer of the outsole;

[0014] Secondly, the inner bottom is obtained by steam molding (foaming) of thermoplastic polyurethane elastomer beads.

[0015] Then, the outsole is fixed to the bottom surface of the lower mold cavity of the mold, and the insole is fixed to the top surface of the upper mold cavity of the mold. After the mold is closed, polyurethane foam material is injected into the space between the two, and the foam is heated to form the insole, which is then directly bonded to the outsole and insole.

[0016] Finally, the material is cooled and demolded to obtain a three-layer composite sole without adhesive bonding.

[0017] The beneficial effects of this utility model are as follows: Compared with the prior art, this utility model overcomes the shortcomings of a single material not being able to simultaneously meet multiple performance requirements such as wear resistance, support, lightness, and comfort by using a glue-free composite of three layers of materials with different properties: the outsole uses high-density polyurethane to provide wear resistance, the midsole uses low-density polyurethane foam to achieve lightweight support, and the insole uses high-resilience foamed thermoplastic elastomer to enhance softness and comfort. The three materials complement each other and produce synergistic effects. At the same time, the midsole directly bonds to the outsole and insole during the foaming process using its own adhesiveness, without the need for adhesives, thus avoiding the problems of glue aging and delamination and environmental pollution. Attached Figure Description

[0018] To more clearly illustrate the technical solutions in this utility model or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only for this utility model. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0019] Figure 1 This is a schematic diagram of the overall structure of an embodiment of the present utility model;

[0020] Figure 2 This is one of the schematic diagrams showing the disassembled structure of an embodiment of this utility model;

[0021] Figure 3This is the second schematic diagram of the disassembled structure of this utility model embodiment;

[0022] Figure 4 for Figure 3 Side view.

[0023] The diagram is marked as follows:

[0024] 1. Insole; 10. Raised section; 2. Midsole; 20. Groove; 3. Outsole. Detailed Implementation

[0025] To make the objectives, technical solutions, and advantages of this utility model clearer, the present utility model will be further described in detail below with reference to specific embodiments.

[0026] It should be noted that, unless otherwise defined, the technical or scientific terms used in this utility model should have the ordinary meaning understood by one of ordinary skill in the art to which this utility model pertains. The terms "first," "second," and similar terms used in this utility model do not indicate any order, quantity, or importance, but are merely used to distinguish different components. Terms such as "comprising" or "including" mean that the element or object preceding the word encompasses the elements or objects listed following the word and their equivalents, without excluding other elements or objects. Terms such as "connected" or "linked" are not limited to physical or mechanical connections, but can include electrical connections, whether direct or indirect. Terms such as "upper," "lower," "left," and "right" are used only to indicate relative positional relationships; when the absolute position of the described object changes, the relative positional relationship may also change accordingly.

[0027] like Figures 1-4 As shown, this utility model provides a glue-free three-layer composite shoe sole, comprising an insole 1, a midsole 2, and an outsole 3 stacked sequentially from top to bottom.

[0028] The insole 1 is formed by molding thermoplastic polyurethane elastomer beads. In this embodiment, the insole 1 uses expanded thermoplastic polyurethane (ETPU) foam beads, which are formed into a highly resilient layered structure through a molding process. The density of the insole 1 is preferably 0.08 g / cm³. This density of foam beads makes the insole 1 soft and comfortable, maintains the arch support shape of the shoe sole, conforms to the contour of the foot, and provides good cushioning and breathability.

[0029] Preferably, the midsole 2 is made of polyurethane foam. The midsole 2 uses thermosetting polyurethane foam or cast polyurethane foam, with a foaming temperature of 45℃-55℃ and a molding temperature of 60℃-65℃. The polyurethane material can fully foam, thereby giving the midsole 2 suitable hardness, weight and elasticity to support the insole 1, maintain the shape of the insole 1 and disperse the impact force during walking.

[0030] In this embodiment, as Figure 2 and Figure 3 As shown, the lower part of the insole 1 is provided with a protrusion 10, and the upper part of the midsole 2 is provided with a groove 20. The protrusion 10 and the groove 20 are matched in shape. When the insole 1 and the midsole 2 are combined, it is equivalent to the protrusion 10 being inserted into the groove 20, thereby increasing the reliability of the combination of the insole 1 and the midsole 2.

[0031] Preferably, the outsole 3 is molded from polyurethane material for wear resistance. The outsole 3 also uses polyurethane material, but its density is greater than that of the insole 2. Specifically, the density of the outsole 3 is 0.60 g / cm³ to 1.20 g / cm³, while the density of the insole 2 is 0.10 g / cm³ to 0.30 g / cm³. Simultaneously, the volume of the outsole 3 is smaller than the sum of the volumes of the other parts, and its thickness is thinner. This "dual-density, same-material" structure ensures the wear resistance of the outsole 3 while achieving overall lightweighting through the large-volume, low-density design of the insole 2 and the inner sole 1.

[0032] In a specific preparation example of this utility model, the following steps are adopted:

[0033] Step 1: Inject the polyurethane raw material of the outsole 3 into the mold and pre-cur it at 80°C for 2 minutes to obtain a thin layer of outsole 3;

[0034] Step 2: Fill the mold with thermoplastic elastomer beads (ETPU) for inner bottom 1, and then heat it with high-temperature and high-pressure steam. During heating, the surface of the beads melts and fuses together under pressure. After cooling water is introduced, the mold cools and solidifies, thus obtaining inner bottom 1 (density after foaming: 0.08 g / cm³).

[0035] Step 3: Fix the completed outsole 3 to the bottom surface of the lower mold cavity of the mold, and fix the insole 1 to the top surface of the upper mold cavity of the mold. After closing the mold, inject liquid polyurethane foam raw material into the space between the outsole 3 and the insole 1 at the foaming temperature (45℃-55℃), raise the temperature to 60℃, keep it at the temperature for 5 minutes, and foam to form the midsole 2, which is simultaneously combined with the outsole 3 and the insole 1.

[0036] Step 4: Cool and demold to obtain a glue-free three-layer composite sole.

[0037] It is understood that this utility model is not limited to the specific values ​​and materials mentioned above. The foamed thermoplastic elastomer of the insole 1 can also be foamed polyamide elastomer (PEBA), foamed ethylene-vinyl acetate copolymer (EVA), etc.; the polyurethane materials of the midsole 2 and outsole 3 can be thermoplastic polyurethane (TPU) or thermosetting polyurethane, as long as they meet the requirements that "the density of the outsole 3 is greater than the density of the midsole 2", "direct bonding without glue", and "the volume of the outsole 3 is less than the sum of the volumes of other parts of the sole". The molding temperature of the midsole 2, 60℃-65℃, can be adjusted according to the actual material system, as long as the midsole 2 has sufficient surface tack during the molding process to bond the insole 1 and the outsole 3.

[0038] This utility model is intended to cover all such substitutions, modifications, and variations that fall within the broad scope of the appended claims. Therefore, any omissions, modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this utility model should be included within the protection scope of this utility model.

Claims

1. A three-layer composite sole without adhesive bonding, characterized in that, Including those stacked from top to bottom: The insole (1) is made of thermoplastic polyurethane elastomer beads by compression molding, which is used to maintain the arch support shape of the shoe sole; The midsole (2) is made of polyurethane foam. Outsole (3) is molded from polyurethane material for wear resistance; The density of the outsole (3) is greater than that of the midsole (2), the volume of the outsole (3) is less than the sum of the volumes of the other parts of the sole, and the midsole (2) is directly bonded to the insole (1) and the outsole (3) respectively without adhesive.

2. The adhesive-free three-layer composite sole according to claim 1, characterized in that, The density of the inner bottom (1) is 0.08 g / cm³.

3. The adhesive-free three-layer composite sole according to claim 1, characterized in that, The foaming temperature of the midsole (2) is 45℃-55℃, and the molding temperature is 60℃-65℃.

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