Integrally-formed hollow-structure pike racket and preparation method thereof

Abstract

The invention relates to an integrally-formed hollow-structure Pick racket and a preparation method thereof, and belongs to the technical field of Pick rackets. The hollow cavity shell is filled with the foam core layer, an opening is formed in the hollow cavity shell, and the foam core layer is obtained by conducting heat treatment foaming on a foaming raw material; the method further comprises the following steps that an integrally-formed hollow cavity shell with an opening is obtained through a blow molding technology; the hollow cavity shell is filled with foaming raw materials; the filled hollow cavity shell is subjected to heat treatment, so that the foaming raw materials are foamed, expanded and fused in the shell, and a foam core layer tightly combined with the shell is formed; according to the Pick racket, an adhesive interface existing in a traditional spliced racket is structurally and thoroughly eliminated, the risk of adhesive failure and layering after long-term use or damp is fundamentally avoided, the structural integrity of the racket is greatly improved, and the durable life of the racket is greatly prolonged.

Description

Technical Field

[0001] This invention belongs to the field of Peak racket technology, specifically relating to a one-piece molded hollow structure Peak racket and its manufacturing method. Background Technology

[0002] Most mainstream Peak rackets currently employ a "sandwich" composite structure, where a fiber-reinforced composite panel (such as carbon fiber or glass fiber) is bonded to a polymer core (such as polymer honeycomb or foam material) using adhesives. However, under long-term, repeated impact loads and changes in environmental temperature and humidity, the adhesive interface between the panel and the core is prone to stress concentration, leading to adhesive aging, delamination, and even separation. This compromises the racket's structural integrity and significantly shortens its lifespan. Furthermore, the bonding process requires high production precision, making it difficult to ensure consistent performance across all rackets. To address these technical shortcomings, this invention provides a one-piece molded hollow structure Peak racket and its manufacturing method. Summary of the Invention

[0003] The purpose of this invention is to provide a one-piece molded hollow structure Peak racket and its manufacturing method, in order to solve the problems mentioned in the background art.

[0004] The objective of this invention can be achieved through the following technical solutions:

[0005] A one-piece molded hollow structure Peak racket includes a hollow cavity shell and a foam core layer filled inside the hollow cavity shell. The hollow cavity shell has an opening, and the foam core layer is obtained by foaming raw materials through heat treatment.

[0006] As a further technical solution of the present invention: the opening on the outer shell is located at the connection of the handle.

[0007] As a further technical solution of the present invention: the foaming raw material includes expanded polystyrene, expanded polypropylene, or expanded polyurethane.

[0008] As a further technical solution of the present invention: the foamed polyurethane comprises the following raw materials in parts by weight: 100 parts polyether polyol, 80-120 parts polyisocyanate, 5-10 parts modified hollow glass microspheres, 1.5-3.5 parts water, 5-15 parts foaming agent, 1-3 parts foam stabilizer, and 0.5-2.5 parts catalyst. The modified hollow glass microspheres are prepared by the following steps: S1. A silane coupling agent is grafted onto the surface of hollow glass microspheres to obtain hollow glass microspheres with double bonds. S2. Reactive hollow glass microspheres are obtained by reacting hollow glass microspheres with diethanolamine through a Michael addition reaction. S3. Modified hollow glass microspheres are obtained by reacting reactive hollow glass microspheres with chlorinated fatty acids in a quaternary ammonium salt reaction.

[0009] As a further technical solution of the present invention: the silane coupling agent structure contains at least one double bond.

[0010] As a further technical solution of the present invention: the heat treatment foaming conditions are heat treatment at a temperature of 70-90℃ for 40-120 minutes.

[0011] A method for manufacturing a one-piece hollow structure Peak racket includes the following steps: A hollow cavity shell with an opening is obtained through blow molding process; The foaming material is filled into the hollow cavity shell; The hollow cavity shell after filling is heat-treated to cause the foaming material to foam, expand and fuse inside the shell, forming a foam core layer that is tightly bonded to the shell.

[0012] As a further technical solution of the present invention: the raw materials for the hollow blow-molded shell include one or more of polypropylene, polyethylene, polycarbonate, polyamide, and polyethylene terephthalate.

[0013] As a further technical solution of the present invention: the polycarbonate is bisphenol A polycarbonate.

[0014] As a further technical solution of the present invention: the polyamide is one of nylon 6 and nylon 66.

[0015] The beneficial effects of this invention are: 1) This invention utilizes a hollow shell made of materials such as polypropylene, polyethylene, polycarbonate, polyamide, or polyethylene terephthalate, prepared by blow molding. This shell inherently possesses excellent impact resistance and rigidity. Based on this, a polyurethane foam core layer is directly filled and reacted within the shell, forming a dense, integrated structure between the shell and the core layer. This structure completely eliminates the adhesive interface present in traditional spliced ​​rackets, fundamentally avoiding the risks of delamination and separation after long-term use or exposure to moisture, thus greatly improving the structural integrity and lifespan of the racket.

[0016] 2) This invention modifies the hollow glass microspheres in the foaming raw material. After modification, the hollow glass microspheres have multiple hydroxyl groups grafted on their surface. During the foaming process, these hydroxyl groups can react with the isocyanate groups in the polyisocyanate to form stable chemical bonds, which significantly improves the interfacial bonding force between the hollow glass microspheres and the polyurethane foam, enhances the stress transmission and dispersion effect of the filler-modified hollow glass microspheres, and improves the compressive strength and modulus of the foam core layer.

[0017] 3) This invention modifies the hollow glass microspheres in the foaming raw material. The modified hollow glass microspheres have both carboxyl and quaternary ammonium salt structures on their surface. The carboxyl and quaternary ammonium salt structures can form weak ionic bonds. When subjected to impact (such as hitting a ball), these ionic bonds can first undergo reversible breakage and recombination with the covalent bonds of the main chain, actively absorbing and dissipating a large amount of impact energy, significantly improving the impact toughness and fatigue resistance of the foam core layer, and reducing the vibration felt when hitting the racket. Detailed Implementation

[0018] The technical solution of the present invention will be clearly and completely described below with reference to the embodiments of the present invention. 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 of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0019] It should be understood that the expression “one or more of…” individually includes each of the objects described after the expression, as well as various different combinations of two or more of the described objects, unless otherwise understood from the context and usage. The expression “and / or” combined with three or more described objects should be understood to have the same meaning, unless otherwise understood from the context.

[0020] It should be understood that the use of “including,” “having,” or “containing,” including its grammatical synonyms, should generally be understood as open-ended and non-restrictive, for example, not excluding other unstated elements or steps, unless otherwise specifically stated or understood from the context.

[0021] It should be understood that the order of the steps or the order in which certain actions are performed is not important as long as the invention remains operational. Furthermore, two or more steps or actions can be performed simultaneously.

[0022] Furthermore, the numerical ranges and parameters used to define the present invention are approximate values, and the relevant values ​​in the specific embodiments have been presented as precisely as possible. However, any value inevitably contains standard deviations due to individual test methods. Therefore, unless explicitly stated otherwise, it should be understood that all ranges, quantities, values, and percentages used in this disclosure are modified with the word "approximately". Here, "approximately" generally means that the actual value is within plus or minus 10%, 5%, 1%, or 0.5% of a specific value or range.

[0023] Example 1 A one-piece molded hollow structure Peak racket includes a hollow cavity shell and a foam core layer filled inside the hollow cavity shell. The hollow cavity shell has an opening located at the end of the handle, and the opening can be closed by a sealing screw plug. The foam core layer is obtained by heat treatment and foaming of a foaming raw material, and the foaming raw material includes the following parts by weight: 100 parts polyether polyol, 80 parts polyisocyanate, 5 parts modified hollow glass microspheres, 1.5 parts water, 5 parts foaming agent, 1 part foam stabilizer, and 0.5 parts catalyst.

[0024] The polyether polyol is polyethylene glycol 6000, the polyisocyanate is diphenylmethane diisocyanate, the blowing agent is hydrofluoroolefin blowing agent HFO-1234ze, the foam stabilizer is DK-580DG, the catalyst is dibutyltin dilaurate, and the modified hollow glass microspheres are prepared by the following steps: S1. By mass fraction, 1 part allyltriethoxysilane, 5 parts hollow glass microspheres, and 20 parts 40% ethanol aqueous solution are mixed in a reaction vessel. After stirring, the mixture is reacted at 40°C for 5 hours. After the reaction is completed, the solid is separated by filtration and the obtained solid is washed with anhydrous ethanol and deionized water in sequence and then dried to obtain hollow glass microspheres with double bonds. S2. By mass, 5 parts of hollow glass microspheres with double bonds, 0.54 parts of diethanolamine, 0.14 parts of 7-methyl-1,5,7-triazabicyclo[4.4.0]dec-5-ene, and 20 parts of acetonitrile were mixed in a reaction vessel. After turning on the magnetic stirrer, the reaction was carried out at 50°C for 8 hours. After the reaction was completed, the solid was separated by filtration and the obtained solid was washed with anhydrous ethanol and deionized water in sequence and then dried to obtain reactive hollow glass microspheres. S3. By mass, 5 parts of reactive hollow glass microspheres, 0.75 parts of 3-chloropropionic acid, and 20 parts of acetonitrile are mixed in a reaction vessel. After magnetic stirring is turned on, the mixture is stirred at 45°C for 20 hours. After the reaction is completed, the solid is separated by filtration and the obtained solid is washed with anhydrous ethanol and deionized water in sequence and then dried to obtain modified hollow glass microspheres.

[0025] A method for manufacturing a one-piece hollow structure Peak racket includes the following steps: Step 1: Mix 60 parts polycarbonate, 40 parts polyamide, 10 parts glass fiber, 2 parts compatibilizer, 0.3 parts antioxidant, and 0.5 parts lubricant by weight and melt extrude them. The melt extrusion temperature conditions are 180℃ in zone 1, 220℃ in zone 2, 240℃ in zone 3, and 230℃ in zone 4. Then, place the preform obtained by melt extrusion into a mold at 60℃ and blow mold it under a blow molding pressure of 1.2MPa to obtain a hollow cavity shell. The second step is to mix the foaming material and fill it into the hollow cavity shell, filling it to 70% of the volume of the hollow cavity mold. Then, the foaming material is heat-treated at 70℃ for 120 minutes and then cured at 50℃ for 8 hours to obtain the foam core layer. After that, the hollow cavity shell is sealed with a sealing screw plug, and anti-slip straps are wrapped around the handle of the sealed hollow cavity shell to obtain a one-piece hollow structure Peak racket.

[0026] In this embodiment, the polycarbonate used is bisphenol A polycarbonate, the polyamide used is nylon 6, the compatibilizer used is styrene-maleic anhydride copolymer, the antioxidant used is a mixture of 0.25 parts antioxidant 1010 and 0.05 parts antioxidant 168, and the lubricant used is calcium stearate.

[0027] Example 2 A one-piece molded hollow structure Peak racket includes a hollow cavity shell and a foam core layer filled inside the hollow cavity shell. The hollow cavity shell has an opening located at the end of the handle, and the opening can be closed by a sealing screw plug. The foam core layer is obtained by heat treatment and foaming of a foaming raw material, and the foaming raw material contains the following parts by weight: 100 parts polyether polyol, 100 parts polyisocyanate, 7.5 parts modified hollow glass microspheres, 2.5 parts water, 10 parts foaming agent, 2 parts foam stabilizer, and 1.5 parts catalyst.

[0028] Wherein, the polyether polyol is polyethylene glycol 4500, the polyisocyanate is isophorone diisocyanate, the blowing agent is hydrofluoroolefin blowing agent HFO-1336mzz, the foam stabilizer is BD-2104, the catalyst is stannous octoate, and the modified hollow glass microspheres are prepared by the following steps: S1. By mass fraction, 1.5 parts of methacryloyloxypropyltrimethoxysilane, 7.5 parts of hollow glass microspheres, and 30 parts of 60% ethanol aqueous solution were mixed in a reaction vessel. After stirring, the mixture was reacted at 50°C for 3.5 hours. After the reaction was completed, the solid was separated by filtration and the obtained solid was washed with anhydrous ethanol and deionized water in sequence and then dried to obtain hollow glass microspheres with double bonds. S2. By mass, 7.5 parts of hollow glass microspheres with double bonds, 0.66 parts of diethanolamine, 0.18 parts of 7-methyl-1,5,7-triazabicyclo[4.4.0]dec-5-ene, and 30 parts of acetonitrile were mixed in a reaction vessel. After turning on the magnetic stirrer, the mixture was reacted at 65°C for 5.5 h. After the reaction was completed, the solid was separated by filtration and the obtained solid was washed with anhydrous ethanol and deionized water in sequence and then dried to obtain reactive hollow glass microspheres. S3. By mass, 7.5 parts of reactive hollow glass microspheres, 0.68 parts of 3-chloropropionic acid, and 30 parts of acetonitrile were mixed in a reaction vessel. After magnetic stirring was turned on, the mixture was stirred at 60°C for 14 hours. After the reaction was completed, the solid was separated by filtration and the obtained solid was washed with anhydrous ethanol and deionized water in sequence and then dried to obtain modified hollow glass microspheres.

[0029] A method for manufacturing a one-piece hollow structure Peak racket includes the following steps: Step 1: Mix 50 parts polypropylene, 50 parts polyethylene, 15 parts glass fiber, 3.5 parts compatibilizer, 0.55 parts antioxidant, and 1 part lubricant by weight and melt extrude them. The melt extrusion temperature conditions are 190℃ in zone 1, 230℃ in zone 2, 250℃ in zone 3, and 240℃ in zone 4. Then, place the preform obtained by melt extrusion into a mold at a temperature of 75℃ and blow mold it under a blow molding pressure of 0.9MPa to obtain a hollow cavity shell. The second step is to mix the foaming material and fill it into the hollow cavity shell, filling it to 60% of the volume of the hollow cavity mold. Then, the foaming material is heat-treated at 80℃ for 80 minutes and then cured at 45℃ for 12 hours to obtain the foam core layer. After that, the hollow cavity shell is sealed with a sealing screw plug, and anti-slip straps are wrapped around the handle of the sealed hollow cavity shell to obtain a one-piece hollow structure Peak racket.

[0030] In this embodiment, the compatibilizer used is a styrene-maleic anhydride copolymer, the antioxidant used is a mixture of 0.5 parts antioxidant 1035 and 0.05 parts antioxidant 168, and the lubricant used is zinc stearate.

[0031] Example 3 A one-piece molded hollow structure Peak racket includes a hollow cavity shell and a foam core layer filled inside the hollow cavity shell. The hollow cavity shell has an opening located at the end of the handle, and the opening can be closed by a sealing screw plug. The foam core layer is obtained by heat treatment and foaming of a foaming raw material, and the foaming raw material contains the following parts by weight: 100 parts polyether polyol, 120 parts polyisocyanate, 10 parts modified hollow glass microspheres, 3.5 parts water, 15 parts foaming agent, 3 parts foam stabilizer, and 2.5 parts catalyst.

[0032] Wherein, the polyether polyol is polyethylene glycol 3000, the polyisocyanate is hexamethylene diisocyanate, the blowing agent is cyclopentane, the foam stabilizer is TEGOSTAB® B 8523, the catalyst is stannous octoate, and the modified hollow glass microspheres are prepared by the following steps: S1. By mass fraction, 2 parts of vinyltriethoxysilane, 10 parts of hollow glass microspheres, and 40 parts of 80% ethanol aqueous solution are mixed in a reaction vessel. After stirring, the mixture is reacted at 60°C for 2 hours. After the reaction is completed, the solid is separated by filtration and the obtained solid is washed with anhydrous ethanol and deionized water in sequence and then dried to obtain hollow glass microspheres with double bonds. S2. By mass, 10 parts of hollow glass microspheres with double bonds, 1.2 parts of diethanolamine, 0.24 parts of 7-methyl-1,5,7-triazabicyclo[4.4.0]dec-5-ene, and 40 parts of acetonitrile were mixed in a reaction vessel. After turning on the magnetic stirrer, the mixture was reacted at 80°C for 3 hours. After the reaction was completed, the solid was separated by filtration and the obtained solid was washed with anhydrous ethanol and deionized water in sequence and then dried to obtain reactive hollow glass microspheres. S3. By mass, 10 parts of reactive hollow glass microspheres, 1.2 parts of 3-chloropropionic acid, and 40 parts of acetonitrile are mixed in a reaction vessel. After magnetic stirring is turned on, the mixture is stirred at 80°C for 6 hours. After the reaction is completed, the solid is separated by filtration and the obtained solid is washed with anhydrous ethanol and deionized water in sequence and then dried to obtain modified hollow glass microspheres.

[0033] A method for manufacturing a one-piece hollow structure Peak racket includes the following steps: Step 1: By weight, mix 60 parts polyethylene terephthalate, 40 parts polyamide, 20 parts glass fiber, 5 parts compatibilizer, 0.8 parts antioxidant, and 1.5 parts lubricant and melt extrude them. The melt extrusion temperature conditions are 200℃ in zone 1, 240℃ in zone 2, 260℃ in zone 3, and 250℃ in zone 4. Then, place the preform obtained by melt extrusion into a mold at a temperature of 90℃ and blow mold it under a blow molding pressure of 0.6MPa to obtain a hollow cavity shell. The second step is to mix the foaming material and fill it into the hollow cavity shell, filling it to 50% of the volume of the hollow cavity mold. Then, the foaming material is heat-treated at 90℃ for 40 minutes and then cured at 40℃ for 16 hours to obtain the foam core layer. After that, the hollow cavity shell is sealed with a sealing screw plug, and anti-slip straps are wrapped around the handle of the sealed hollow cavity shell to obtain a one-piece hollow structure Peak racket.

[0034] In this embodiment, the polyamide used is nylon 66, the compatibilizer used is styrene-maleic anhydride copolymer, the antioxidant used is a mixture of 0.7 parts antioxidant 1076 and 0.1 parts antioxidant 168, and the lubricant used is ethylene bis-stearamide.

[0035] Based on the above embodiments 1-3, the present invention also provides a hollow structure Peak racket prepared by using expanded polystyrene or expanded polypropylene as foaming raw material.

[0036] Comparative Example 1 The difference between this comparative example and Example 3 is that the hollow glass microspheres are not modified. Instead, an equal amount of unmodified hollow glass is used to replace the hollow glass microspheres in the raw materials, while the other conditions and the mass fractions of the raw materials remain unchanged.

[0037] A one-piece molded hollow structure Peak racket includes a hollow cavity shell and a foam core layer filled inside the hollow cavity shell. The hollow cavity shell has an opening located at the end of the handle, and the opening can be closed by a sealing screw plug. The foam core layer is obtained by heat treatment and foaming of a foaming raw material, and the foaming raw material contains the following parts by weight: 100 parts polyether polyol, 120 parts polyisocyanate, 10 parts hollow glass microspheres, 3.5 parts water, 15 parts foaming agent, 3 parts foam stabilizer, and 2.5 parts catalyst.

[0038] The polyether polyol is polyethylene glycol 3000, the polyisocyanate is hexamethylene diisocyanate, the foaming agent is cyclopentane, the foam stabilizer is TEGOSTAB® B 8523, and the catalyst is stannous octoate.

[0039] A method for manufacturing a one-piece hollow structure Peak racket includes the following steps: Step 1: Mix 60 parts polycarbonate, 40 parts polyamide, 20 parts glass fiber, 5 parts compatibilizer, 0.8 parts antioxidant, and 1.5 parts lubricant by weight and melt extrude them. The melt extrusion temperature conditions are 200℃ in zone 1, 240℃ in zone 2, 260℃ in zone 3, and 250℃ in zone 4. Then, place the preform obtained by melt extrusion into a mold at a temperature of 90℃ and blow mold it under a blow molding pressure of 0.6MPa to obtain a hollow cavity shell. The second step is to mix the foaming material and fill it into the hollow cavity shell, filling it to 50% of the volume of the hollow cavity mold. Then, the foaming material is heat-treated at 90℃ for 40 minutes and then cured at 40℃ for 16 hours to obtain the foam core layer. After that, the hollow cavity shell is sealed with a sealing screw plug, and anti-slip straps are wrapped around the handle of the sealed hollow cavity shell to obtain a one-piece hollow structure Peak racket.

[0040] In this embodiment, the polycarbonate used is bisphenol A polycarbonate, the polyamide used is nylon 66, the compatibilizer used is styrene-maleic anhydride copolymer, the antioxidant used is a mixture of 0.7 parts antioxidant 1076 and 0.1 parts antioxidant 168, and the lubricant used is ethylene bis-stearamide.

[0041] Experimental Example 1 The performance of the Peak rackets obtained in Examples 1-3 and Comparative Example 1 was tested. The compressive strength and compressive modulus of the foam core layer in each component sample were tested according to the national standard GB / T8813-2020 "Determination of Compressive Properties of Rigid Foamed Plastics". The rebound rate of the foam core layer in each component sample was tested according to the national standard GB / T 6670-2008 "Determination of Rebound Performance of Flexible Foamed Polymer Materials by Falling Ball Method". The impact absorption energy of the foam core layer in each component sample was tested according to the national standard GB / T 18941-2003 "Determination of Impact Fatigue of Porous Polymer Materials under Constant Load". The falling ball impact fatigue life of each component racket was also tested. A 500g steel ball was dropped freely from 0.5m above the impact sweet spot of the racket until visible cracks appeared on the racket surface. The number of impacts at which visible cracks appeared on the racket surface was recorded. A higher number of impacts indicates better dynamic fatigue performance of the racket. The test results are shown in Table 1. Table 1

[0042] As shown in Table 1, unmodified hollow glass microspheres are prone to agglomeration, resulting in numerous unevenly distributed weak areas. These weak areas lead to a significant decrease in the performance of the foam core layer. Furthermore, due to the poor interfacial bonding between the unmodified hollow glass microspheres and the polyurethane foam core layer, these weak interfacial areas become stress concentration points after repeated shots, leading to the initial formation of microcracks. This results in a decrease in the fatigue resistance of the foam core layer, ultimately causing it to lose its supporting effect on the racket shell and resulting in racket breakage.

[0043] This article uses specific examples to illustrate the principles and implementation methods of the present invention. The descriptions of the above embodiments are only for the purpose of helping to understand the method and core ideas of the present invention, including the best mode, and also to enable any person skilled in the art to practice the present invention, including manufacturing and using any device or system, and implementing any combined method. It should be noted that for those skilled in the art, several improvements and modifications can be made to the present invention without departing from the principles of the present invention, and these improvements and modifications also fall within the protection scope of the claims of the present invention.

Claims

1. A one-piece molded hollow structure Peak racket, characterized in that, It includes a hollow cavity shell and a foam core layer filled inside the hollow cavity shell, wherein the hollow cavity shell has an opening, and the foam core layer is obtained by foaming raw material through heat treatment.

2. The hollow structure Peak racket according to claim 1, characterized in that, An opening is provided on the outer casing at the connection point of the handle.

3. The hollow structure Peak racket according to claim 1, characterized in that, The foaming raw materials include expanded polystyrene, expanded polypropylene, or expanded polyurethane.

4. The hollow structure Peak racket according to claim 3, characterized in that, The foamed polyurethane comprises the following raw materials in parts by weight: 100 parts polyether polyol, 80-120 parts polyisocyanate, 5-10 parts modified hollow glass microspheres, 1.5-3.5 parts water, 5-15 parts foaming agent, 1-3 parts foam stabilizer, and 0.5-2.5 parts catalyst. The modified hollow glass microspheres are prepared by the following steps: S1. A silane coupling agent is grafted onto the surface of hollow glass microspheres to obtain hollow glass microspheres with double bonds. S2. Reactive hollow glass microspheres are obtained by reacting hollow glass microspheres with diethanolamine through a Michael addition reaction. S3. Modified hollow glass microspheres are obtained by reacting reactive hollow glass microspheres with chlorinated fatty acids in a quaternary ammonium salt reaction.

5. The hollow structure Peak racket according to claim 4, characterized in that, The silane coupling agent contains at least one double bond in its structure.

6. The hollow structure Peak racket according to claim 1, characterized in that, The heat treatment foaming conditions are as follows: heat treatment at 70-90℃ for 40-120 minutes.

7. A method for manufacturing a one-piece molded hollow structure Peak racket as described in claim 1, characterized in that, Includes the following steps: A hollow cavity shell with an opening is obtained through blow molding process; The foaming material is filled into the hollow cavity shell; The hollow cavity shell after filling is heat-treated to cause the foaming material to foam, expand and fuse inside the shell, forming a foam core layer that is tightly bonded to the shell.

8. The method for preparing a one-piece molded hollow structure Peak racket according to claim 7, characterized in that, The raw materials for hollow blow-molded shells include one or more of polypropylene, polyethylene, polycarbonate, polyamide, and polyethylene terephthalate.

9. The method for preparing a one-piece molded hollow structure Peak racket according to claim 8, characterized in that, The polycarbonate is bisphenol A polycarbonate.

10. The method for preparing a one-piece molded hollow structure Peak racket according to claim 8, characterized in that, The polyamide is one of nylon 6 and nylon 66.

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