Two-piece sole structure and shoe thereof

Abstract

The application provides a two-section sole structure and shoes thereof, and belongs to the technical field of shoemaking. The two-section sole structure comprises a front section foamed outsole, a rear section foamed outsole and an intermediate rubber connecting piece connecting the front section foamed outsole and the rear section foamed outsole; the front section foamed outsole and the rear section foamed outsole are provided with a lap joint surface in a lap joint area with the intermediate rubber connecting piece. By optimizing the hardness, thickness and lap joint process of the intermediate rubber connecting piece, the bending resistance and interface bonding durability of the bending area are effectively improved.

Description

Technical Field

[0001] This application belongs to the field of footwear technology, specifically relating to a two-section sole structure and the footwear thereof. Background Technology

[0002] In the footwear industry, foamed material outsoles are widely used in athletic shoes, casual shoes, and women's shoes due to their lightweight, cushioning, and comfort.

[0003] However, traditional one-piece foam outsoles are prone to material fatigue, cracking, or structural breakage in areas that are used for a long time or subjected to repeated bending (such as the metatarsophalangeal joint), which affects the lifespan of the shoes. Summary of the Invention

[0004] In order to solve at least one of the technical problems existing in the background art, this application provides a two-section shoe sole structure, which effectively improves the flexural resistance and interfacial adhesion durability of the bending area by optimizing the hardness, thickness and overlapping process of the middle rubber connecting piece.

[0005] The technical solution adopted in this application is as follows: The first aspect of this application provides a two-section shoe sole structure, including: A front section of foamed outsole, a rear section of foamed outsole, and an intermediate rubber connecting piece connecting the front section of foamed outsole and the rear section of foamed outsole; The front foam outsole and the rear foam outsole have overlapping surfaces in the overlapping area with the middle rubber connecting piece.

[0006] According to the two-section sole structure provided in the first aspect of this application, by segmenting the traditional one-piece foam outsole in the frequently bending metatarsophalangeal region, the stress concentration problem during dynamic stress is effectively decoupled: the front and rear sections use lightweight, highly elastic foam materials (such as EVA or foamed TPU) to ensure the cushioning and overall lightweight of the sole; while the middle connecting area is physically connected by an independent rubber connecting piece. This rubber piece has the flexibility to adapt to bending requirements and tear resistance, and can withstand repeated deformation during each step or movement without easily breaking. The overlapping surface design increases the bonding area between the foam outsole and the rubber connecting piece, providing a structural basis for subsequent interface treatment and firm bonding, which not only improves the feasibility of the assembly process, but also significantly enhances the interlayer bonding strength and durability.

[0007] According to one embodiment of this application, the intermediate rubber connecting piece has a 1.5 mm non-adhesive area reserved at the edge of the bonding area with the front foam outsole and the rear foam outsole.

[0008] According to one embodiment of this application, the overlapping surfaces of the front foam outsole and the rear foam outsole are coated with a treatment agent and a water-based adhesive.

[0009] According to one embodiment of this application, the intermediate rubber connecting piece has a hardness of 40 to 45 Shore A and a thickness of 3 mm.

[0010] According to one embodiment of this application, the overlap width of the overlapping surface is 35 mm.

[0011] A second aspect of this application provides a shoe including a two-section sole structure as described in any of the embodiments of the first aspect. Attached Figure Description

[0012] The accompanying drawings, which are included to provide a further understanding of this application and form part of this application, illustrate exemplary embodiments and are used to explain this application, but do not constitute an undue limitation of this application. In the drawings: Figure 1 This is a schematic diagram of the two-section shoe sole structure provided in the embodiments of this application; in, 11. Front section foam outsole; 12. Rear section foam outsole; 13. Middle rubber connecting piece. Detailed Implementation

[0013] To more clearly illustrate the overall concept of this application, a detailed explanation is provided below with reference to the accompanying drawings.

[0014] Many specific details are set forth in the following description to provide a thorough understanding of this application. However, this application may also be implemented in other ways different from those described herein. Therefore, the scope of protection of this application is not limited to the specific embodiments disclosed below. It should be noted that, unless otherwise specified, the embodiments of this application and the features thereof can be combined with each other.

[0015] Furthermore, it should be understood in the description of this application that the terms "top", "bottom", "inner", "outer", "axial", "radial", "circumferential", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, and are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this application.

[0016] In this application, unless otherwise expressly 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 part; they can refer to a mechanical connection, an electrical connection, or a communication connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components. Those skilled in the art can understand the specific meaning of the above terms in this application according to the specific circumstances.

[0017] In this application, unless otherwise expressly specified and limited, the "above" or "below" of the second feature can mean that the first and second features are in direct contact, or that the first and second features are in indirect contact through an intermediate medium. In the description of this specification, references to terms such as "an embodiment," "some embodiments," "example," "specific example," or "some examples," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of this application. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described can be combined in any suitable manner in one or more embodiments or examples.

[0018] like Figure 1 As shown, a first aspect of this application provides a two-section shoe sole structure, including: Front section foam outsole 11, rear section foam outsole 12, and intermediate rubber connecting piece 13 connecting the front section foam outsole 11 and the rear section foam outsole 12; The front section foam outsole 11 and the rear section foam outsole 12 have overlapping surfaces in the overlapping area with the middle rubber connecting piece 13.

[0019] According to the two-section sole structure provided in the first aspect of this application, by segmenting the traditional one-piece foam outsole in the frequently bending metatarsophalangeal region, the stress concentration problem during dynamic stress is effectively decoupled: the front and rear sections use lightweight, highly elastic foam materials (such as EVA or foamed TPU) to ensure the cushioning and overall lightweight of the sole; while the middle connecting area is physically connected by an independent rubber connecting piece. This rubber piece has the flexibility to adapt to bending requirements and tear resistance, and can withstand repeated deformation during each step or movement without easily breaking. The overlapping surface design increases the bonding area between the foam outsole and the rubber connecting piece, providing a structural basis for subsequent interface treatment and firm bonding, which not only improves the feasibility of the assembly process, but also significantly enhances the interlayer bonding strength and durability.

[0020] In some embodiments of this application, the intermediate rubber connecting piece 13 has a 1.5 mm non-adhesive area reserved at the edge of the bonding area with the front foam outsole 11 and the rear foam outsole 12.

[0021] In actual use, the bonding edges of shoe soles are the areas with the most significant stress concentration, especially during repeated bending. Micro-cracks easily form at the interface between the adhesive layer and different materials and gradually expand, eventually leading to delamination or interface peeling. By proactively reserving a 1.5 mm uncoated area at the edge of the bonding area, it is possible to effectively prevent adhesive overflow during the pressing process, avoiding the formation of thick edges or stress concentration points. It also prevents rigid transitions caused by adhesive buildup at the edges, resulting in smoother and more continuous deformation between materials. Furthermore, this uncoated area reduces the risk of edge lifting caused by adhesive aging, thermal expansion and contraction, or moisture penetration, improving the long-term durability of the interface. From a process perspective, this design helps control the precision of adhesive application, preventing excess adhesive from contaminating the mold or affecting the appearance, and improving production consistency.

[0022] In some embodiments of this application, the overlapping surfaces of the front foam outsole 11 and the rear foam outsole 12 are coated with a treatment agent and a water-based adhesive. Because foam outsoles (such as EVA, TPU, etc.) have poor surface density, high porosity, and contain residual release agents, their surface energy is low, making them prone to insufficient adhesion and easy delamination when directly bonded to rubber. By first coating the overlapping surfaces with a treatment agent, the surface can be effectively cleaned, the release layer removed, and the foam material modified to enhance its wettability and chemical bonding with the adhesive. Subsequently, a water-based adhesive is applied, which is not only environmentally friendly and non-toxic, meeting modern green manufacturing requirements, but also possesses good initial tack, flexibility, and resistance to damp heat aging, enabling it to adapt to dynamic stress changes in complex environments. The water-based polyurethane adhesive also forms a strong and tough adhesive film after curing, firmly connecting the porous foam to the dense rubber material, ensuring no interlayer delamination occurs during repeated bending.

[0023] In some embodiments of this application, the intermediate rubber connecting piece 13 has a hardness of 40 to 45 Shore A and a thickness of 3 mm. This parameter design is a key technical feature for achieving the optimal balance between flexibility, support, and durability in a two-piece sole structure. Controlling the hardness within the Shore A range of 40–45 gives the rubber connecting piece moderate elasticity and softness, allowing it to conform to the natural bending of the foot during walking or exercise, effectively alleviating stress concentration in the metatarsophalangeal joint area and avoiding the risk of cracking due to excessive stiffness. It also provides sufficient structural support to prevent excessive deformation that could lead to material fatigue or collapse. Compared to traditional rigid connectors or high-hardness rubbers (such as those above Shore A 60), this hardness range significantly improves wearing comfort and dynamic fit. Simultaneously, the 3 mm thickness design ensures connection strength and dimensional stability while balancing the overall thinness of the sole and space utilization. This thickness is sufficient to withstand the shear and tensile stresses generated by repeated bending and provides ample bonding volume for the overlapping surfaces, enhancing the reliability of the interface bonding. Practice has shown that when the hardness of the rubber connecting piece exceeds this range or the thickness is less than 2 mm, it is very easy for the material to break or the glue to come undone during the flex test. However, by using a Shore hardness of 40–45 and a thickness of 3 mm, combined with optimized processes, the performance of the finished shoe in 30,000 to 40,000 flex tests can be significantly improved, delaying the formation of cracks and meeting the dual requirements of high-end women's shoes for durability and comfort.

[0024] In some embodiments of this application, the overlap width of the overlapping surfaces is 35 mm. In the two-section sole structure, the forefoot foam outsole 11 and the rearfoot foam outsole 12 are bonded together in the overlapping area by a middle rubber connecting piece 13. The overlap width directly affects the bonding area and the interface load-bearing capacity. An overly narrow overlap width will result in insufficient effective bonding area, making it prone to local peeling or delamination due to stress concentration during repeated bending or dynamic stress. On the other hand, an overly wide design will increase material usage, leading to increased sole weight and potentially limiting bending flexibility, thus affecting wearing comfort. Actual testing and process optimization have shown that when the overlap width is set to 35 mm, it provides sufficient bonding contact surface, allowing stress to be evenly distributed along the bonding interface, significantly improving shear and peel resistance, and also adapting to the spatial layout of the transition area from the forefoot to the midfoot in conventional women's shoes or casual shoes, avoiding structural redundancy. This width, combined with surface treatment, special adhesives, and pressing processes, can effectively support the finished shoe to pass high-frequency flexing tests (such as more than 30,000 times), and no obvious material breakage or delamination was observed during two consecutive months of actual wear testing.

[0025] A second aspect of this application provides a shoe including the two-section sole structure described in any of the first aspects above.

[0026] This shoe effectively solves the technical problems of fatigue cracking and structural breakage that traditional one-piece foam outsoles are prone to during long-term wear or repeated bending by employing a segmented high-performance outsole design. The two-section outsole structure uses lightweight, highly elastic foam material in the forefoot and heel areas for cushioning and weight reduction. Simultaneously, a 3 mm thick intermediate rubber connecting piece with a hardness of 40–45 Shore A is introduced in the metatarsophalangeal flex area, giving this area excellent flexibility and tear resistance. This allows the outsole to conform to the natural flexion of the foot during walking or exercise, significantly reducing localized stress concentration. A 35 mm overlap bonding surface, combined with surface treatment and water-based adhesive bonding technology, ensures a strong and durable interface between the forefoot and rear foam outsole and the rubber connecting piece. The 1.5 mm non-adhesive area reserved at the bonding edge further enhances edge peel resistance, preventing lifting or cracking caused by adhesive layer buildup. Actual wear testing showed that after two months of continuous wear, the sole of the shoe showed normal wear, and there was no glue separation or breakage at the joints, demonstrating excellent structural stability and durability.

[0027] For any parts not mentioned in this application, existing technologies may be used or referenced.

[0028] The various embodiments in this specification are described in a progressive manner. The same or similar parts between the various embodiments can be referred to each other. Each embodiment focuses on describing the differences from other embodiments.

[0029] The above description is merely an embodiment of this application and is not intended to limit this application. Various modifications and variations can be made to this application by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this application should be included within the protection scope of this application.

Claims

1. A two-section shoe sole structure, characterized in that, include: A front section of foamed outsole, a rear section of foamed outsole, and an intermediate rubber connecting piece connecting the front section of foamed outsole and the rear section of foamed outsole; The front section foam outsole and the rear section foam outsole have overlapping surfaces in the overlapping area with the middle rubber connecting piece; The intermediate rubber connecting piece has a 1.5 mm non-adhesive area reserved at the edge of the bonding area with the front foam outsole and the rear foam outsole; The overlapping surfaces of the front and rear foam outsoles are coated with a treatment agent and a water-based adhesive.

2. The two-section sole structure according to claim 1, characterized in that, The intermediate rubber connecting piece has a hardness of 40 to 45 Shore A and a thickness of 3 mm.

3. The two-section sole structure according to claim 1, characterized in that, The overlap width of the overlapping surfaces is 35 mm.

4. A shoe, characterized in that, Includes the two-section sole structure as described in any one of claims 1 to 3.

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