Pickleball paddle based on composite construction and manufacturing process thereof

Abstract

The application discloses a pick-up racket based on a composite structure and relates to the technical field of pick-up rackets.The racket face body of the pick-up racket is provided with a plurality of composite layers which are stacked from inside to outside, and is provided with a carbon fiber face plate and a carbon fiber bottom plate which are attached to the upper and lower parts of the racket face body, so that a rigid-flexible integrated overall structure is formed.The EPP closed-cell foam layer of the core layer stores and releases impact energy in the process of hitting a ball by virtue of the closed-cell foaming structure, provides sufficient elastic rebounding basis, and improves the problem that the rebounding is poor due to the rigidity of the racket face in the prior art.The high-modulus modified polypropylene (MPP) transition layer which is attached to the outer side of the core layer guarantees the rigid transmission of hitting force by virtue of the high-modulus characteristic, reduces the loss in the energy transmission process, cooperates with the EPP core layer to realize efficient energy conversion, improves the ball control feeling and the holding comfort, optimizes the hitting sweet spot and the fault tolerance, and finally guarantees the structural strength of the racket while taking into account the rebounding performance, the ball control performance and the long-term use reliability.

Description

Technical Field

[0001] This invention relates to the field of Peak racket technology, specifically to Peak rackets based on composite structures and their manufacturing process. Background Technology

[0002] A Peak racket is a specialized hitting instrument for the sport of Peakball. It generally consists of a racket face and a handle connected to the side of the racket face. The layered structure and material configuration of the racket face directly determine the ball rebound performance, ball control feel, and structural durability, and are the core components that determine the overall performance of the racket.

[0003] As described in the published patent CN119818920A, pickleball is a racket-based sport that combines features of badminton, tennis, and table tennis. The pickle racket is a key tool used in pickleball, and its material, weight, and grip all affect a player's performance. Choosing the right pickle racket is crucial for improving shot quality and enjoying the sport.

[0004] Peak rackets currently offer a variety of material options, including lightweight yet strong carbon fiber plates, cost-effective fiberglass, EVA, PE, honeycomb paper, and hybrid materials. These different materials vary in weight, durability, and feel, allowing players to choose according to their needs and preferences. Furthermore, the manufacturing processes for different materials also differ.

[0005] Based on their characteristics, Peak rackets can be divided into control rackets and power rackets. Control rackets primarily function to allow players to control the ball at the net, utilizing the longer the ball stays on the racket face to give the player time to adjust the racket angle and guide the ball to its desired destination. The racket's manufacturing requirements dictate that the racket face is neither too stiff nor too soft, allowing the ball to feel rested on the face, giving the player time to adjust the racket angle and control the ball's trajectory. This is what is meant by a control racket. Power rackets are mainly used for attacking or quickly returning the ball to the opponent, with the faster the return, the better. A fast return makes it difficult for the opponent to see the ball's trajectory, leaving them with no chance to retaliate. These rackets require high overall strength and rigidity, as well as good racket face elasticity and moderate stiffness. The player's arm doesn't need to exert much force to hit the ball quickly, resulting in a hitting speed twice as fast as a control racket, yet requiring less effort. This is what is meant by a power racket.

[0006] To improve the elasticity of the Peak racket face, elastic materials, such as foam, are filled inside the racket face during the manufacturing process. In existing technology, the structure of a Peak racket filled with foam includes a foam core, a carbon fiber faceplate, and a carbon fiber backplate. The carbon fiber faceplate and backplate are respectively glued to the top and bottom surfaces of the foam core, filling the entire racket face. The advantage of this structure is its overall lightness and good overall resilience. However, its disadvantages are also significant. Because the foam core is relatively soft, it lacks a supporting structure inside the racket face, resulting in a lack of support for the entire racket face. The racket face will collapse and deform after prolonged use, rendering the entire Peak racket unusable. Furthermore, the manufacturing process for this type of Peak racket is relatively simple. Foam material is directly foamed into the shape of the racket face using a foaming mold. Then, the carbon fiber faceplate and backplate are glued to the top and bottom surfaces of the foam core, followed by pressing and curing. Finally, edge strips and grip tape are wrapped around the racket. The traditional manufacturing process for producing Peak rackets filled with foam has the following drawbacks: the foam core material is pre-made and pre-formed. During the sealing and pressing process of bonding the carbon fiber faceplate and carbon fiber base plate, gaps are easily left inside the racket face. This results in the foam core material not completely filling the entire internal cavity of the racket face. Due to the gaps left in the manufacturing process, hollowness or abnormal noise may occur, making it difficult to guarantee product quality.

[0007] In summary, most existing Peak rackets use a simple composite structure with a hard surface layer and a single core layer, which raises the question of whether the racket's structural strength and rebound can be balanced. Summary of the Invention

[0008] To overcome the shortcomings mentioned above, the present invention aims to provide a technical solution that can solve the above problems.

[0009] To achieve the above objectives, the present invention provides the following technical solution: The Peak racket based on a composite structure includes a racket face body and a handle connected to the side of the racket face body. The racket face body includes a multi-layer composite structure stacked from the inside to the outside, a carbon fiber panel attached to the upper surface of the multi-layer composite structure, and a carbon fiber base plate attached to the lower surface of the multi-layer composite structure. The multi-layer composite structure includes a core layer, a transition layer, an outer layer, and an edge protection structure. The core layer includes an EPP closed-cell foam layer; The transition layer includes a high-modulus modified polypropylene (MPP) layer, which is attached to the outside of the core layer. The outer layer includes a TPE elastomer layer, which is attached to the outside of the transition layer and extends toward the handle; The edge protection structure includes a foamed buffer strip arranged circumferentially along the outer layer.

[0010] As a further aspect of the present invention: a preset gap is arranged on both sides of the core layer, and the width of the preset gap is 2mm.

[0011] As a further aspect of the present invention: the core layer includes a 9P type EPP closed-cell foam layer with a density range of 20kg / m³ to 200kg / m³, a resilience greater than 90%, and a compressive strength of 0.5MPa to 2MPa under 10% strain conditions.

[0012] As a further aspect of the present invention: the transition layer comprises an 80KG type high modulus modified polypropylene MPP layer.

[0013] As a further aspect of the present invention: the core layer is arranged in the shape of a regular square, and the corners of the core layer of the regular square are provided with rounded corner structures.

[0014] As a further aspect of the present invention: the transition layer extends toward the handle with a first tapered extension, and the outer layer includes a second tapered extension that covers the first tapered extension.

[0015] As a further aspect of the present invention: the handle is made of polypropylene (PP) material, and the handle is rigidly connected to the outer layer; The handle is honeycomb-shaped, and the honeycomb holes are arranged with the front and back surfaces facing each other. The edge protection structure extends and covers the outside of the handle; The carbon fiber panel and carbon fiber base plate extend to cover the handle.

[0016] The Peak racket manufacturing process based on a composite structure, used to prepare the aforementioned Peak racket, includes the following steps: S1, Core material prefabrication and activation: A 9P type EPP closed-cell foam core layer with a square shape and rounded corners is prepared by compression molding and foaming. 2mm thick peelable spacers are symmetrically attached to the core layer at the set positions on both sides. Then, the outer surface of the core layer is activated by low-temperature plasma etching to improve the surface interface bonding energy. S2, In-mold co-melting composite transition layer: The activated core layer is positioned in the cavity of the temperature-controlled composite mold. Molten 80KG high-modulus modified polypropylene MPP is injected into the outer side of the core layer and the conical area extending towards the handle. The mold temperature is controlled to cause the surface of the EPP core layer to undergo micro-melting, forming a molecular-level fusion interface with the MPP melt. The transition layer covering the core layer and the first conical extension extending towards the handle are integrally formed. After cooling and solidification, the side partitions are removed, forming a preset gap with a width of 2mm between the core layer and the outer layer. S3, Co-extruded integral outer layer and protective structure: The core material component with the transition layer is placed into the co-extrusion injection mold. Using a dual-material co-extrusion process, TPE thermoplastic elastomer is injection molded on the outer surface of the transition layer and the outer side of the first conical extension to form an outer layer. Simultaneously, foamed buffer strips are continuously extruded in the circumferential direction of the outer layer, so that a second conical extension is formed at the position of the outer layer corresponding to the first conical extension. The circumferential foamed buffer strip is integrally fused with the outer layer and extends towards the handle to form a continuous edge shock absorption and protection structure. S4, Injection Molded Honeycomb Handle: The racket face body with the outer layer composite is placed into the handle molding mold as an insert, so that the second conical extension extends into the handle cavity, and polypropylene (PP) melt is injected. The honeycomb handle is formed by forming holes through the removable mold core along the front and rear racket face directions, so that the PP handle and the outer layer form a rigid integral connection. At the same time, the edge shock absorption and protection structure is simultaneously covered on the outer surface of the handle. S5, segmented hot-pressed carbon fiber surface layer: carbon fiber prepreg is laid on the upper and lower end faces of the multi-layer composite structure and the handle area, and placed into a hot-press mold. The process of segmented heating and gradient pressure is used to cure and form the carbon fiber panel and carbon fiber base plate, so that the carbon fiber panel and carbon fiber base plate are tightly bonded to the upper and lower end faces of the multi-layer composite structure, and extend towards the handle to form a continuous reinforcing layer. After cooling and demolding, a complete composite structure Peak racket is obtained.

[0017] Compared with the prior art, the beneficial effects of the present invention are as follows: The Peak racket of this invention features a multi-layered composite structure on its racket face, stacked sequentially from the inside out. This, combined with upper and lower carbon fiber panels and a carbon fiber base plate, creates a balanced and flexible overall design. The core layer, an EPP closed-cell foam layer, stores and releases impact energy during impact, providing ample elastic rebound and addressing the problem of poor rebound caused by an overly stiff racket face in existing technologies. The high-modulus modified polypropylene (MPP) transition layer, bonded to the outside of the core layer, ensures rigid transmission of striking power due to its high modulus properties, reducing energy loss during transmission. This, along with the EPP core layer, further enhances the racket's rigidity. The synergistic design achieves efficient energy conversion; the TPE elastomer outer layer, which adheres to the outside of the transition layer and extends towards the handle, effectively attenuates vibrations generated by the shot, improving ball control and grip comfort; the foamed buffer strips set along the circumference of the outer layer serve as an edge protection structure, which can not only buffer the impact of bumps on the edge of the racket face, but also improve the overall durability and service life of the racket by combining the fatigue resistance of EPP and the high modulus properties of MPP, but also help dissipate racket face vibrations, further optimizing the sweet spot and margin of error, ultimately ensuring the structural strength of the racket while taking into account rebound performance, ball control performance and long-term reliability. Attached Figure Description

[0018] Figure 1 This is a three-dimensional structural view of the present invention; Figure 2This is an exploded view of the structure of the present invention; Figure 3 This is another exploded view of the structure of the present invention; Figure 4 This is a front view of the internal structure of the present invention; Figure 5 yes Figure 4 A partial view at point A in the middle; The reference numerals and names in the figure are as follows: Core layer - 100, transition layer - 200, outer layer - 300, edge protection structure - 400, carbon fiber panel - 500, carbon fiber base plate - 600, handle - 700, preset gap - 800. Detailed Implementation

[0019] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0020] Please see Figure 1-5 The Peak racket based on a composite structure includes a racket face body and a handle 700 connected to the side of the racket face body. The racket face body includes a multi-layer composite structure stacked from the inside to the outside, a carbon fiber panel 500 attached to the upper surface of the multi-layer composite structure, and a carbon fiber base plate 600 attached to the lower surface of the multi-layer composite structure. The multi-layer composite structure includes a core layer 100, a transition layer 200, an outer layer 300, and an edge protection structure 400. The core layer includes an EPP closed-cell foam layer; The transition layer includes a high-modulus modified polypropylene (MPP) layer, which is attached to the outside of the core layer. The outer layer includes a TPE elastomer layer, which is attached to the outside of the transition layer and extends toward the handle; The edge protection structure includes a foamed buffer strip arranged along the outer circumferential direction; like Figure 1 and 2 As shown, the main body of the Peak racket's face adopts a multi-layer composite structure that is stacked from the inside out, forming a rigid and flexible overall structure with the upper and lower carbon fiber panels and carbon fiber base plate. Among them, the carbon fiber panel and carbon fiber base plate on the surface can provide a high rigidity hitting surface, ensuring the stability of the racket face shape at the moment of impact, avoiding power loss and deviation of the hitting direction caused by excessive deformation of the racket face. At the same time, it forms a "hard shell and soft core" combination with the internal multi-layer soft structure, which improves the technical problems of insufficient elasticity and weak rebound of existing pure hard racket faces from the structural root. The core layer of EPP closed-cell foam relies on its own independent and closed cell structure. When the ball is impacted, the kinetic energy of the impact is converted into elastic potential energy through the compression deformation of the cells. After the impact load disappears, the cells quickly reset and release the stored energy, realizing active elastic rebound and significantly improving the ball ejection effect. At the same time, the closed-cell foam structure has excellent fatigue resistance. It is not easy to experience elastic decay and structural collapse after repeated hits. In addition, the closed-cell structure does not absorb water, which can prevent the racket weight from increasing and the performance from decreasing in humid environments, thus improving the stability of use in different humidity scenarios. The high-modulus modified polypropylene MPP transition layer, which is attached to the outside of the core layer, serves as a modulus gradient transition structure to bridge the modulus difference between the soft EPP core and the outer layer structure. This avoids delamination and delamination problems caused by inconsistent deformation amplitude at the soft and hard interface, thus improving the reliability of the interlayer bonding. On the other hand, relying on its own high modulus properties, it evenly distributes the impact force of the shot to the entire racket face, preventing local stress concentration from causing damage to the foam layer. At the same time, it ensures the linearity of power transmission, reduces the internal loss of energy during the transmission process, and allows the swing power to be efficiently transferred to the hitting point, improving the controllability and output efficiency of the hitting power. The TPE elastomer outer layer, which is attached to the outside of the transition layer and extends towards the handle, effectively reduces the vibration amplitude and the vibration transmitted to the hand due to the high damping properties of the material itself, thereby improving grip comfort and ball control accuracy. The structure that extends towards the handle allows the vibration to continue to decay along the path of transmission to the handle, further weakening the residual vibration at the handle and improving the stability of the feel during long-term shots. At the same time, the good toughness of the TPE material can form a protective wrap around the internal composite structure, reducing the damage to the internal layers caused by scratches during daily use. The foamed buffer strips arranged along the outer circumference serve as an edge protection structure. When the racket edge is bumped or accidentally lands, the foamed buffer strips can absorb the impact energy through their own compression deformation, preventing the carbon fiber layer and composite layer at the edge from being directly impacted and cracking or delaminating. This improves the edge's impact resistance and the overall lifespan of the racket. At the same time, when the hitting point is close to the edge of the racket face, the foamed buffer strips can help absorb the impact vibration, reduce the difference in rebound between the edge area and the center sweet spot, expand the effective hitting sweet spot, and improve the hit tolerance. In addition, the circumferentially arranged buffer structure can balance the circumferential stiffness distribution of the racket face, reduce racket face torsion during the hit, and improve the stability of the hitting direction. In summary, the main body of the Peak racket of this invention adopts a multi-layered composite structure stacked sequentially from the inside out, and together with the upper and lower carbon fiber panels and carbon fiber base plate, it forms an overall configuration that combines rigidity and flexibility. The core layer, an EPP closed-cell foam layer, stores and releases impact energy during impact through its closed-cell foam structure, providing a sufficient foundation for elastic rebound and improving the problem of poor rebound caused by an overly stiff racket face in existing technologies. The high-modulus modified polypropylene (MPP) transition layer, attached to the outside of the core layer, ensures the rigid transmission of hitting power with its high modulus characteristics, reducing energy loss during transmission, and complementing the EPP core... The core layer works synergistically to achieve efficient energy conversion; the TPE elastomer outer layer, which adheres to the outside of the transition layer and extends towards the handle, effectively attenuates vibrations generated by the shot, improving ball control and grip comfort; the foamed buffer strips set along the circumference of the outer layer serve as an edge protection structure, which can not only buffer the impact of bumps on the edge of the racket face, but also improve the overall durability and service life of the racket by combining the fatigue resistance of EPP and the high modulus properties of MPP, but also help dissipate racket face vibrations, further optimizing the sweet spot and margin of error, ultimately ensuring the structural strength of the racket while taking into account rebound performance, ball control performance and long-term reliability.

[0021] In this embodiment of the invention, a preset gap is arranged on both sides of the core layer, and the width of the preset gap is 2mm; like Figure 3 and 5 As shown, a 2mm wide pre-set gap is set on both sides of the core layer. By reserving an independent buffer space between the core layer and the outer structure, and taking advantage of the low stress transmission characteristics of the air medium, when the core layer is subjected to the impact of the ball and generates compression deformation and internal stress, it provides a release margin for the radial deformation of the core layer. At the same time, it partially blocks the direct rigid transmission path of stress waves and vibrations from the core layer to the outer layer, weakening the stress amplitude transmitted outward. It can reduce the vibration energy transmitted to the outer layer and handle through stress isolation, reduce hand vibration during hitting, improve comfort and ball control stability during long-term holding, and give the core layer more deformation, further release the elastic rebound potential of EPP closed-cell foam, optimize the rebound performance of hitting the ball, and at the same time alleviate the interfacial stress caused by the difference in modulus between the core layer and the outer heterogeneous material layers, reduce the probability of interlayer debonding failure, optimize the overall stiffness distribution of the racket face, expand the effective sweet spot, and improve the tolerance of hitting the ball.

[0022] In this embodiment of the invention, the core layer includes a 9P type EPP closed-cell foam layer with a density range of 20kg / m³ to 200kg / m³, a resilience greater than 90%, and a compressive strength of 0.5MPa to 2MPa under 10% strain conditions. like Figure 2As shown, the core layer uses a 9P type EPP closed-cell foam layer with a density range of 20kg / m³ to 200kg / m³, a resilience greater than 90%, and a compressive strength of 0.5MPa to 2MPa under 10% strain. During operation, relying on the material's uniform and independent closed-cell structure, the cells undergo controllable elastic compressive deformation under the impact of the ball, converting the impact kinetic energy into stored elastic potential energy. After the impact load disappears, the stored energy is quickly restored and released due to the high resilience of over 90%. Furthermore, the compressive strength of 0.5MPa to 2MPa under 10% strain ensures that the deformation remains within the elastic range under normal ball-hitting conditions, avoiding plastic collapse and permanent performance degradation. The density range of 20kg / m³ to 200kg / m³ strikes a balance between lightweight design and structural support, controlling the overall weight of the racket and reducing the user's swing burden. It also provides stable internal support for the upper and lower carbon fiber layers, preventing the racket face from denting and deforming. The rebound rate of more than 90% effectively improves the energy return efficiency of the shot and enhances the rebound performance of the racket face. It specifically addresses the problems of excessively stiff racket faces and insufficient rebound in existing technologies. The compressive strength of 0.5MPa to 2MPa makes the racket face deformation moderate and controllable, balancing clear elastic feedback and precise ball control. At the same time, the stable material performance parameters ensure the consistency of racket performance during mass production. Combined with the excellent fatigue resistance and impact resistance of the 9P type EPP closed-cell foam, it can effectively extend the service life of the racket. In one embodiment, 9P type EPP closed-cell foam is a high-resilience foamed polypropylene sub-brand product optimized for sports equipment such as Peak rackets. It belongs to the closed-cell thermoplastic engineering foam material and is the core functional substrate of the racket's core layer. "9P type" is a common "number + P" specification naming method in the EPP foamed polypropylene industry, used to distinguish material categories with different densities and resilience levels. The number usually corresponds to the material's density level and performance grade, and P stands for polypropylene foam series. This series belongs to high-resilience modified EPP, and by adjusting the foaming ratio, it can cover the density range of 20kg / m³ to 200kg / m³, thereby adapting to different requirements for resilience, support rigidity, and lightweighting.

[0023] In this embodiment of the invention, the transition layer comprises an 80KG type high modulus modified polypropylene MPP layer; like Figure 3As shown, the transition layer uses an 80KG type high modulus modified polypropylene MPP layer. During operation, relying on its own 80KG type corresponding high modulus structural characteristics, it forms a stiffness gradient transition interface between the soft EPP core layer and the TPE outer layer. During the hit, it bears the local impact stress transmitted by the core layer and evenly diffuses the concentrated hitting force to the entire racket face structure. While ensuring the uniform release of rebound energy, it maintains the linearity of force transmission with its own rigidity, reduces the energy loss between layers, and can also bridge the modulus difference between the core layer and the outer layer, weakening the shear stress caused by the difference in deformation amplitude at the soft and hard interface. The high modulus property provides stable rigid support for the racket face, preventing excessive flexible deformation during impact and ensuring precise control of the direction and power output of the shot. This effectively improves the efficiency of power transmission. At the same time, the gradient transition configuration strengthens the reliability of the interlayer bonding and reduces the risk of delamination and cracking that can easily occur when soft and hard materials are directly bonded. Combined with the excellent impact resistance and creep resistance of modified polypropylene, it can maintain stable support and transmission performance after long-term repeated hitting, extending the service life of the racket structure.

[0024] In this embodiment of the invention, the core layer is arranged in the shape of a regular square, and the corners of the core layer of the regular square are provided with rounded corner structures; like Figure 3 As shown, the core layer is arranged in a regular square shape with rounded corners. The square core material shape is compatible with the outline of the Peak racket face, which can evenly fill the effective hitting area inside the racket face. This allows the elastic support and rebound performance of the core layer to cover the entire hitting surface as much as possible, so that the impact stress generated during the hitting process can be evenly transmitted and diffused along the core material plane. The rounded corner structure can change the stress transmission path, so that the stress that would normally accumulate at the right angle tip can be smoothly dispersed along the arc interface, avoiding local stress peaks from exceeding the material's bearing capacity limit. The regular quadrilateral layout maximizes the effective support area of ​​the core layer, ensuring uniform rebound feedback and support stiffness in different areas of the racket face. This improves the stability of the hitting feel and the controllability of the landing point. The rounded corner structure effectively eliminates the stress concentration problem at right-angle corners, reducing the probability of cracking, collapse, and interlayer interface delamination at the corners of the core material under long-term repeated impacts. This improves the fatigue resistance of the core layer and the service life of the overall structure. At the same time, the smooth rounded corner transition allows for a tighter and smoother fit between the core layer and the outer transition layer and edge shock absorption structure, reducing assembly gaps and interface defects, and strengthening the overall integrity of the multi-layer structure.

[0025] In this embodiment of the invention, the transition layer extends toward the handle with a first tapered extension, and the outer layer includes a second tapered extension that covers the first tapered extension; like Figure 3 and 4As shown, the transition layer extends towards the handle to form a first conical extension, and the outer layer covers the second conical extension along the first conical extension. Relying on the high modulus property of the first conical extension, a gradually narrowing rigid transmission skeleton is constructed between the racket face and the handle, which smoothly transmits the force and vibration generated by the racket face hitting the ball to the handle along the conical cross section. The gradual change of the cross section avoids stress concentration caused by sudden changes in stiffness. The second conical extension covering the outside of the first conical extension, with the high damping characteristics of TPE material, forms a continuous attenuation effect throughout the transmission of vibration to the grip area. At the same time, the double-conical gradual configuration allows the connection contour from the throat to the handle to achieve a smooth transition. The first tapered extension continues the rigid support of the transition layer, ensuring efficient transmission of hitting power and rebound energy from the racket face to the handle, reducing energy loss at the connection point, and improving the overall consistency and clarity of force feedback. The wrap-around damping structure of the second tapered extension can gradually reduce the vibration amplitude transmitted to the hand, reduce grip vibration, and improve hand comfort and ball control stability during long-term hitting. The gradient tapered shape can disperse the alternating stress at the connection point between the racket face and the handle, reducing the probability of delamination and breakage in the connection area after repeated hitting, improving the fatigue resistance and service life of the overall structure. At the same time, the smooth transition contour can optimize the grip fit, and the outer elastomer can also increase grip friction and enhance grip stability.

[0026] In this embodiment of the invention, the handle is made of polypropylene (PP) material, and the handle is rigidly connected to the outer layer; The handle is honeycomb-shaped, and the honeycomb holes are arranged with the front and back surfaces facing each other. The edge protection structure extends and covers the outside of the handle; The carbon fiber panel and carbon fiber base plate extend and cover the handle; like Figure 2 As shown, the PP material handle, with its moderate rigidity and toughness, forms a continuous rigid transmission path with the outer layer, ensuring that the hitting force is smoothly transmitted between the racket face and the handle. The honeycomb holes arranged along the front and back racket face can maintain stable structural support in the direction of the hitting force by taking advantage of the axial load-bearing characteristics of the honeycomb structure. At the same time, the micro-deformation of the hole wall absorbs some of the impact energy. The extended edge protection structure can continue the shock absorption path of the racket face and perform secondary attenuation of the vibration transmitted to the handle. The carbon fiber panel and base plate extending to the handle can strengthen the structural integrity of the connection area and improve the bending and torsional stiffness of the handle. The PP material handle has good moldability and controllable cost. The rigid connection design reduces energy loss at the joint, improves the overall power transmission and feedback clarity. The honeycomb structure effectively reduces the weight while ensuring the structural strength of the handle, optimizing the overall weight balance of the racket. The holes are set along the direction of force to maximize the structural load-bearing efficiency and prevent the handle from bending and deforming under heavy hits. The extended edge protection structure can not only cushion the impact of the handle and improve the structural durability, but also enhance the grip friction, reduce hand vibration, and improve the comfort and grip stability of long-term hitting. The extended carbon fiber surface further strengthens the anti-torsion performance of the handle joint, making the power transmission more direct and accurate. At the same time, the wear-resistant properties of carbon fiber can improve the service life of the handle surface.

[0027] The Peak racket manufacturing process based on a composite structure, used to prepare the aforementioned Peak racket, includes the following steps: S1, Core material prefabrication and activation: A 9P type EPP closed-cell foam core layer with a square shape and rounded corners is prepared by compression molding and foaming. 2mm thick peelable spacers are symmetrically attached to the core layer at the set positions on both sides. Then, the outer surface of the core layer is activated by low-temperature plasma etching to improve the surface interface bonding energy. S2, In-mold co-melting composite transition layer: The activated core layer is positioned in the cavity of the temperature-controlled composite mold. Molten 80KG high-modulus modified polypropylene MPP is injected into the outer side of the core layer and the conical area extending towards the handle. The mold temperature is controlled to cause the surface of the EPP core layer to undergo micro-melting, forming a molecular-level fusion interface with the MPP melt. The transition layer covering the core layer and the first conical extension extending towards the handle are integrally formed. After cooling and solidification, the side partitions are removed, forming a preset gap with a width of 2mm between the core layer and the outer layer. S3, Co-extruded integral outer layer and protective structure: The core material component with the transition layer is placed into the co-extrusion injection mold. Using a dual-material co-extrusion process, TPE thermoplastic elastomer is injection molded on the outer surface of the transition layer and the outer side of the first conical extension to form an outer layer. Simultaneously, foamed buffer strips are continuously extruded in the circumferential direction of the outer layer, so that a second conical extension is formed at the position of the outer layer corresponding to the first conical extension. The circumferential foamed buffer strip is integrally fused with the outer layer and extends towards the handle to form a continuous edge shock absorption and protection structure. S4, Injection Molded Honeycomb Handle: The racket face body with the outer layer composite is placed into the handle molding mold as an insert, so that the second conical extension extends into the handle cavity, and polypropylene (PP) melt is injected. The honeycomb handle is formed by forming holes through the removable mold core along the front and rear racket face directions, so that the PP handle and the outer layer form a rigid integral connection. At the same time, the edge shock absorption and protection structure is simultaneously covered on the outer surface of the handle. S5, segmented hot-pressed carbon fiber surface layer: carbon fiber prepreg is laid on the upper and lower end faces of the multi-layer composite structure and the handle area, and placed into a hot-press mold. The process of segmented heating and gradient pressure is used to cure and form the carbon fiber panel and carbon fiber base plate, which are tightly bonded to the upper and lower end faces of the multi-layer composite structure and extend towards the handle to form a continuous reinforcing layer. After cooling and demolding, a complete composite structure Peak racket is obtained. The process is carried out in sequence according to the following steps: core material pre-activation, in-mold co-melting composite transition layer, co-extrusion integral molding of outer layer and protective structure, injection molding of honeycomb handle, and segmented hot-pressing coating of carbon fiber surface layer. During the operation, a 9P type EPP closed-cell foam core layer with rounded corner structure is first obtained by compression molding foaming. 2mm thick peelable spacers are attached to both sides of the core layer to reserve gaps. Then, the surface interface energy of the core material is improved by low-temperature plasma etching to provide a basis for high-strength bonding between layers. Then, the activated core material is placed into a zoned temperature-controlled composite mold and molten 80KG of high-modulus modified polypropylene MPP is injected. Through precise temperature control, the surface of the EPP core layer is micro-melted to form a molecular-level fusion interface with the MPP melt. The transition layer covering the core layer and the first conical extension extending to the handle are integrally molded. After cooling and shaping, the spacers are removed to form a precisely 2mm pre-set gap, which replaces the traditional adhesive method and fundamentally improves the interfacial bonding strength of soft and hard materials. Subsequently, a dual-material co-extrusion process is used to injection mold TPE thermoplastic elastomer onto the outer surface of the transition layer and the outer side of the first conical extension to form an outer layer. Simultaneously, a foamed buffer strip is continuously extruded circumferentially on the outer layer, forming a covered second conical extension at the position corresponding to the first conical extension. The circumferential foamed buffer strip is fused integrally with the outer layer and extends towards the handle to form a continuous edge damping and protection structure, ensuring the integrity and continuity of the damping and shock absorption path. Then, the racket body with the completed outer layer composite is placed as an insert into the handle molding mold. Polypropylene (PP) melt is injected and honeycomb-shaped handles are formed along the front and rear racket surfaces through the holes formed by the removable mold core, so that the PP handle and the outer layer form a rigid integral connection. At the same time, the edge damping and protection structure is simultaneously covered on the outside of the handle to continue the damping and protection effect. Finally, carbon fiber prepreg is laid on the upper and lower end faces of the multi-layer composite structure and the handle area. A hot pressing process with segmented heating and gradient pressure is used to complete the curing and molding, so that the carbon fiber panel is tightly bonded to the base plate and extends towards the handle to form a continuous reinforcing layer, strengthening the bending and torsional resistance of the overall structure. A combination of in-mold co-melting, co-extrusion, injection molding, and segmented hot pressing processes achieves high-strength bonding of multi-layered heterogeneous materials, effectively reducing the risk of delamination and debonding after repeated long-term impacts. Simultaneously, the structural and functional features of each layer are integrally molded, ensuring high dimensional accuracy and consistent performance. This reduces subsequent manual assembly processes and errors, guaranteeing synergistic performance in racket surface rebound, shock absorption, ball control, and durability, while also improving mass production efficiency and product yield. Plasma activation pretreatment and molecular-level fusion further strengthen the interfacial bonding of the heterogeneous materials, while the segmented hot pressing process reduces internal stress accumulation during curing, improving the bonding quality of the carbon fiber surface layer and the long-term structural stability. In one embodiment, when multiple heterogeneous materials are simultaneously hot-pressed and cured, the difference in thermal expansion coefficients will still form residual internal stress after cooling. Under long-term alternating loads, there is a potential risk of interface failure. Therefore, after the multilayer composite structure is formed, it needs to stand still for a period of time before the carbon fiber surface layer and carbon fiber bottom layer are coated to fully release the internal stress.

[0028] It will be apparent to those skilled in the art that the present invention is not limited to the details of the exemplary embodiments described above, and that the invention can be implemented in other specific forms without departing from its spirit or essential characteristics. Therefore, the embodiments should be considered in all respects as exemplary and non-limiting, and the scope of the invention is defined by the appended claims rather than the foregoing description. Thus, all variations falling within the meaning and scope of equivalents of the claims are intended to be included within the present invention. No reference numerals in the claims should be construed as limiting the scope of the claims.

Claims

1. A Peak racket based on a composite structure, characterized in that, The racket includes a racket face body and a handle connected to the side of the racket face body. The racket face body includes a multi-layer composite structure stacked from the inside to the outside, a carbon fiber panel attached to the upper end of the multi-layer composite structure, and a carbon fiber base plate attached to the lower end of the multi-layer composite structure. The multi-layer composite structure includes a core layer, a transition layer, an outer layer, and an edge protection structure. The core layer includes an EPP closed-cell foam layer; The transition layer includes a high-modulus modified polypropylene (MPP) layer, which is attached to the outside of the core layer. The outer layer includes a TPE elastomer layer, which is attached to the outside of the transition layer and extends toward the handle; The edge protection structure includes a foamed buffer strip arranged circumferentially along the outer layer.

2. The Peak racket based on a composite structure according to claim 1, characterized in that, The core layer has pre-set gaps extending from both sides, and the width of the pre-set gaps is 2mm.

3. The Peak racket based on a composite structure according to claim 2, characterized in that, The core layer includes a 9P type EPP closed-cell foam layer with a density range of 20kg / m³ to 200kg / m³, a resilience of more than 90%, and a compressive strength of 0.5MPa to 2MPa under 10% strain conditions.

4. The Peak racket based on a composite structure according to claim 3, characterized in that, The transition layer comprises an 80KG type high modulus modified polypropylene MPP layer.

5. The Peak racket based on a composite structure according to claim 4, characterized in that, The core layer is arranged in the shape of a regular square, and the corners of the core layer are rounded.

6. The Peak racket based on a composite structure according to claim 5, characterized in that, The transition layer extends toward the handle with a first tapered extension, and the outer layer includes a second tapered extension that covers the first tapered extension.

7. The Peak racket based on a composite structure according to claim 6, characterized in that, The handle is made of polypropylene (PP) material and is rigidly connected to the outer layer. The handle is honeycomb-shaped, and the honeycomb holes are arranged with the front and back surfaces facing each other. The edge protection structure extends and covers the outside of the handle; The carbon fiber panel and carbon fiber base plate extend to cover the handle.

8. A manufacturing process for Peak rackets based on a composite structure, characterized in that, The method for preparing the Peak racket according to any one of claims 1-7 comprises the following steps: S1, Core material prefabrication and activation: A 9P type EPP closed-cell foam core layer with a square shape and rounded corners is prepared by compression molding and foaming. 2mm thick peelable spacers are symmetrically attached to the core layer at the set positions on both sides. Then, the outer surface of the core layer is activated by low-temperature plasma etching to improve the surface interface bonding energy. S2, In-mold co-melting composite transition layer: The activated core layer is positioned in the cavity of the temperature-controlled composite mold. Molten 80KG high-modulus modified polypropylene MPP is injected into the outer side of the core layer and the conical area extending towards the handle. The mold temperature is controlled to cause the surface of the EPP core layer to undergo micro-melting, forming a molecular-level fusion interface with the MPP melt. The transition layer covering the core layer and the first conical extension extending towards the handle are integrally formed. After cooling and solidification, the side partitions are removed, forming a preset gap with a width of 2mm between the core layer and the outer layer. S3, Co-extruded integral outer layer and protective structure: The core material component with the transition layer is placed into the co-extrusion injection mold. Using a dual-material co-extrusion process, TPE thermoplastic elastomer is injection molded on the outer surface of the transition layer and the outer side of the first conical extension to form an outer layer. Simultaneously, foamed buffer strips are continuously extruded in the circumferential direction of the outer layer, so that a second conical extension is formed at the position of the outer layer corresponding to the first conical extension. The circumferential foamed buffer strip is integrally fused with the outer layer and extends towards the handle to form a continuous edge shock absorption and protection structure. S4, Injection Molded Honeycomb Handle: The racket face body with the outer layer composite is placed into the handle molding mold as an insert, so that the second conical extension extends into the handle cavity, and polypropylene (PP) melt is injected. The honeycomb handle is formed by forming holes through the removable mold core along the front and rear racket face directions, so that the PP handle and the outer layer form a rigid integral connection. At the same time, the edge shock absorption and protection structure is simultaneously covered on the outer surface of the handle. S5, segmented hot-pressed carbon fiber surface layer: carbon fiber prepreg is laid on the upper and lower end faces of the multi-layer composite structure and the handle area, and placed into a hot-press mold. The process of segmented heating and gradient pressure is used to cure and form the carbon fiber panel and carbon fiber base plate, so that the carbon fiber panel and carbon fiber base plate are tightly bonded to the upper and lower end faces of the multi-layer composite structure, and extend towards the handle to form a continuous reinforcing layer. After cooling and demolding, a complete composite structure Peak racket is obtained.

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