A buoy for waterborne photovoltaics and a method of making the same

Abstract

The application discloses a composite buoy for water photovoltaics and a preparation method thereof. The buoy comprises a buoy body, the buoy body comprises a supporting framework, a surface layer composite structure and a core material, the supporting framework is made of a high-corrosion-resistant metal material and is provided with a connecting piece, the surface layer composite structure is formed by compounding and curing of a polyurethane-polyurea elastomer and a fiber reinforced material, and the core material is a polyurethane hard foam. The supporting framework is embedded in the core material and is integrally compounded and formed with the surface layer composite structure and the core material. The preparation method comprises the following steps of mold and material preparation, surface layer composite structure preparation, supporting framework setting, core material foaming and mold closing and curing. The buoy has good structural strength, corrosion resistance, weather resistance, impact resistance and long-term use reliability.

Description

Technical Field

[0001] This invention relates to the technical field of pontoons, and in particular to a pontoon for floating photovoltaic applications and its manufacturing method. Background Technology

[0002] With the continuous growth of global demand for renewable energy, floating photovoltaic (PV) systems, as a form of power generation that saves land resources and improves the comprehensive utilization efficiency of water areas, have been increasingly widely used in recent years. Floating PV systems are typically deployed in lakes, reservoirs, and nearshore waters. Their long-term operation relies on the stable bearing and reliable support of floating support components such as pontoons. Therefore, the structural strength, environmental adaptability, and service life of the pontoons directly affect the operational safety and maintenance economy of the entire floating PV system.

[0003] However, the actual operating environment of floating photovoltaic pontoons is usually quite complex. Especially under conditions of high humidity, high salt spray, strong ultraviolet radiation, continuous wind and wave impact, and tidal erosion, the pontoons must not only withstand long-term immersion and natural aging, but also face adverse factors such as external alternating loads and biological erosion. Therefore, high requirements are placed on the pontoon materials and their overall structure. An ideal pontoon should simultaneously possess high strength, light weight, good corrosion resistance, and a long service life to meet the needs of long-term operation of floating photovoltaic systems.

[0004] Currently, most floating pontoons on the market are made of a single material such as concrete, fiberglass, or HDPE. While these existing pontoons can meet basic floating requirements, they still have certain limitations in complex aquatic environments. For example, some materials are prone to water absorption and degradation under high humidity conditions, as well as damp heat aging. Under long-term ultraviolet radiation, they are also prone to powdering and cracking. HDPE materials, in particular, show significant performance degradation under ultraviolet conditions, thus limiting their service life. At the same time, existing pontoons usually lack active antifouling design, making them susceptible to the attachment of aquatic organisms such as algae and shellfish, resulting in buoyancy loss and structural weight increase. In addition, existing single-material pontoons generally suffer from insufficient rigidity and toughness matching, resulting in limited impact resistance and wave resistance, and relatively poor adaptability to wave environments and extreme climates. Summary of the Invention

[0005] In view of this, it is necessary to provide a floating photovoltaic pontoon and its manufacturing method, which at least solves the problems of insufficient structural strength, poor corrosion resistance and weather resistance, easy aging and cracking, serious biological adhesion, short service life and insufficient overall reliability of existing floating photovoltaic pontoons in complex operating environments such as high humidity, salt spray, ultraviolet radiation and wind and wave impact.

[0006] To solve the above-mentioned technical problems, the present invention provides the following technical solution: In a first aspect, the present invention provides a floating pontoon for marine photovoltaic applications, comprising a pontoon body, the pontoon body comprising: A support frame is installed inside the pontoon body. The support frame is made of highly corrosion-resistant metal material and is provided with connectors for connecting to external structures. A surface composite structure is provided on the outside of the float body. The surface composite structure is formed by the composite curing of polyurethane-polyurea elastomer and fiber reinforcement material. The core material is disposed within the internal space formed by the surface composite structure, and the core material is rigid polyurethane foam. The supporting frame is embedded in the core material and together with the surface composite structure and the core material, it forms an integrated composite pontoon structure.

[0007] In a further embodiment, the highly corrosion-resistant metal material is one of 304 stainless steel, 316 stainless steel, 316L stainless steel, 5-series marine-grade aluminum alloy, or 2205 duplex stainless steel. The surface composite structure is a multi-layer composite structure, which includes, from the outside to the inside, a polyurethane-polyurea elastomer layer, a fiber reinforcement layer, a polyurethane-polyurea elastomer layer, a fiber reinforcement layer, and a polyurethane-polyurea elastomer layer. The fiber reinforcement material is one or more of basalt fiber, aramid fiber, carbon fiber or glass fiber; The core material is rigid polyurethane foam formed by molding foaming, and the density of the rigid polyurethane foam is 150-250 kg / m³.

[0008] Secondly, the present invention provides a method for preparing a floating photovoltaic pontoon, comprising the following steps: S1. Prepare the molds and materials; S2. Polyurethane-polyurea elastomer is laid on the inner surface of the mold, and fiber reinforcement material is laid on it, so that the polyurethane-polyurea elastomer and fiber reinforcement material are combined to form a surface composite structure. S3. After the surface composite structure is formed, the pre-formed support frame is placed in a preset position inside the mold. S4. Inject rigid polyurethane foam raw material into the mold to allow it to foam and form the core material; S5. The mold is closed and cured, so that the surface composite structure, the supporting frame and the core material are integrally formed to obtain the floating pontoon for water photovoltaic.

[0009] In a further embodiment, in step S1, a polyurethane-specific coating agent is applied to the inner surface of the float mold and dried. Before the surface composite structure is prepared, the mold temperature is raised to 40-50℃. The prepared polyurethane-polyurea elastomer components A and B are added to the material tank of the two-component polyurethane casting machine, and the temperature of the material tank is controlled at 40-60℃. Vacuum degassing is carried out for later use. At the same time, the fiber reinforcement material is cut according to the mold size for later use. In step S2, components A and B are transported to a high-speed dynamic mixing head at a low pressure according to a mass ratio of A to B of 100:73.5-74. The transport pressure is 0.5-1MPa and the mixing head speed is 2000-3000 rpm. The components are then injected into the inner surface of the mold at multiple points and spread evenly.

[0010] In a further embodiment, in step S2, after the first layer of polyurethane-polyurea elastomer is surface dry, the fiber reinforcement material is laid on the adhesive film and flattened by rollers and brushes so that the fiber reinforcement material is tightly bonded to the polyurethane-polyurea elastomer. Then, inject polyurethane-polyurea elastomer compound at multiple points and spread it evenly to impregnate the fiber reinforcement material. Repeat this process until the specified number of layers and thickness are reached. At the node positions corresponding to the connectors on the pontoon, reinforcement is achieved by laying an additional layer of polyurethane-polyurea elastomer and reinforcing material composite, and the reinforcing material is cut into a circular ring or trihedral shape.

[0011] In a further embodiment, in step S4, the polyurethane rigid foam components A and B are added to the material tanks of the high-pressure foaming machine, and the temperature of the component A material tank is controlled at 40-60℃, and the temperature of the component B material tank is controlled at 25-30℃. Turn on the high-pressure foaming machine and mix components A and B at a mass ratio of 100:75. The mixing pressure is 20-30MPa and the mixing temperature is 45-50℃. The mixed foaming material is then injected into the lower mold cavity of the mold using a multi-point pouring method. In step S5, after pouring to the designed amount, the mold is closed and locked. The internal pressure is controlled at 0.5MPa and the mold temperature is controlled at 60-80℃ for molding and curing.

[0012] In a further embodiment, after molding and curing, the mold temperature is maintained at 70-80℃ and cured for more than 20 minutes before the mold is opened to obtain the product; Place the product in an 80℃ environment for more than 4 hours to mature, and then leave it at room temperature for more than 24 hours. The product is then trimmed, and the parting line, connector positions, and surface defects are sanded. Polyurethane-polyurea elastomer is then applied to the corresponding areas by brushing or rolling, and the finished product is obtained after curing.

[0013] Thirdly, the present invention provides a polyurethane-polyurea elastomer material for floating photovoltaic pontoons: The polyurethane-polyurea elastomer material is made of component A and component B; Component A includes polyaspartic acid ester, active antibacterial filler, and functional additives; Component B is an aliphatic prepolymer with an NCO% of 8-15%, and is prepared by mixing and reacting IPDI or HMDI with polyol resins PTMG and PPG. The R value of the reaction between components A and B is the isocyanate index n(—NCO) / n(—NH) = 1-1.2, and the mass ratio of components A to B is 100:73.5.

[0014] In a further embodiment, component A comprises, by weight, 45-65 parts of polyaspartic acid ester, 0.3-0.8 parts of wetting and dispersing agent, 0.6-2 parts of defoamer, 0.5-1 parts of thixotropic agent, 2-2.5 parts of nano-sized rutile titanium dioxide, 2-3 parts of nano-sized zinc oxide, 20-45 parts of pigments and fillers, 3-8 parts of dehydrating agent, 0-2 parts of colorant, 0.2-0.5 parts of ultraviolet absorber, and 0.3-1 parts of rheology modifier; The B component comprises, by weight, 100 parts of polyol resin, 50-80 parts of aliphatic isocyanate monomer, and a catalyst.

[0015] In a further embodiment, the rigid polyurethane foam material is formed by the reaction and foaming of component A and component B; Component A comprises, by weight, 80-95 parts of polyether, 5-20 parts of phthalic anhydride polyester polyol, 0.2-0.8 parts of crosslinking agent, 0.5-1.2 parts of N,N-dimethylcyclohexylamine, 1-2.5 parts of foam stabilizer, 8-12 parts of physical foaming agent, 0.2-1.0 parts of water, 15-30 parts of liquid flame retardant, and 20-30 parts of flame retardant filler; Component B is polyphenyl polymethylene polyisocyanate; The mass ratio of component A to component B is 158:115-120. Compared with the prior art, the present invention has the following advantages: By incorporating a support frame and connectors made of highly corrosion-resistant metal materials within the pontoon body, and forming a surface composite structure on the outside composed of polyurethane-polyurea elastomer and fiber-reinforced materials, while simultaneously placing a rigid polyurethane foam core within the internal space enclosed by the surface composite structure, the support frame, surface composite structure, and core material are integrally molded. This approach effectively balances the pontoon's internal load-bearing capacity, external weather protection, impact resistance enhancement, and buoyancy support functions. It addresses the issues of existing single-material pontoons being prone to aging and cracking, insufficient corrosion and weather resistance, and poor load-bearing stability in complex aquatic environments such as high humidity, salt spray, ultraviolet radiation, wave impact, and biological adhesion. Furthermore, the corresponding molding composite manufacturing process ensures a stable bond between the surface composite structure, support frame, and core material, reducing the risk of joint cracking, water ingress failure, and structural delamination. Moreover, the formulation design of the polyurethane-polyurea elastomer and rigid polyurethane foam materials further enhances the pontoon's resistance to salt spray, ultraviolet radiation, antibacterial and antifouling properties, flame retardancy, and long-term service performance, thereby reducing maintenance and replacement frequency and making it more suitable for the long-term stable operation of floating photovoltaic systems.

[0016] To make the above and other objects, features and advantages of the present invention more apparent and understandable, preferred embodiments are described below in detail with reference to the accompanying drawings. Attached Figure Description

[0017] in: Figure 1 This is a schematic diagram of the overall structure of the float for the floating photovoltaic system of the present invention; Figure 2 This is a schematic cross-sectional view of the pontoon structure of the present invention; Figure 3 This is a partial layered schematic diagram of the surface composite structure of the present invention; Figure 4 This is a schematic flowchart of the method for preparing the floating photovoltaic pontoon of the present invention.

[0018] Label Explanation: 1. Support frame; 2. Connectors; 3. Surface composite structure; 31. Polyurethane-polyurea elastomer layer; 32. Fiber reinforcement layer; 4. Core material. Detailed Implementation

[0019] To make the objectives, technical solutions, and beneficial effects of this invention clearer, the invention will be further described below with reference to preferred embodiments. It should be understood that the following embodiments are for illustrative purposes only and are not intended to limit the scope of protection of this invention.

[0020] like Figure 1As shown, this invention provides a floating photovoltaic pontoon and its manufacturing method, suitable for floating photovoltaic support scenarios in lakes, reservoirs, and nearshore waters, especially suitable for floating support conditions under long-term high humidity, salt spray, ultraviolet radiation, and wind and wave impact environments. The pontoon adopts a composite structure design, mainly comprising a pontoon body, which consists of an internal support frame 1, an outer surface composite structure 3, and a floating core material disposed within the internal space enclosed by the surface composite structure 3. The support frame 1 is made of highly corrosion-resistant metal material, the surface composite structure 3 is formed by the composite curing of a polyurethane-polyurea elastomer layer 31 and a fiber reinforcement layer 32, and the floating core material is rigid polyurethane foam. The support frame 1 is embedded within the floating core material and integrally composites with the surface composite structure 3 and the floating core material to form the pontoon body. Through this structural design, the pontoon body simultaneously possesses the comprehensive functions of frame load-bearing, outer layer protection reinforcement, and internal buoyancy support, thereby improving the problems of insufficient strength, poor weather resistance, easy aging and cracking, and short service life of traditional single-material pontoons in complex aquatic environments.

[0021] like Figure 2 As shown, in this embodiment, the support frame 1 can be prefabricated into a corresponding frame structure according to the outer dimensions and load-bearing requirements of the pontoon. Besides providing basic support for the pontoon body, it can also serve as a load-bearing foundation for connection to the external floating photovoltaic module installation structure. Connectors 2 for connection to external structures can be provided on the support frame 1. These connectors 2 can be integrally formed with the support frame 1 or subsequently fixedly connected, facilitating connection and assembly of the pontoon with the photovoltaic bracket, connecting beam, or other floating platform structures. The high corrosion-resistant metal material used for the support frame 1 can be one of 304 stainless steel, 316 stainless steel, 316L stainless steel, 5-series marine-grade aluminum alloy, or 2205 duplex stainless steel. Preferably, 2205 duplex stainless steel is used as the material for the support frame 1 and connector 2. A comparison of its main properties with 304 stainless steel, 316L stainless steel, and 5083 marine-grade aluminum alloy is shown in the table below.

[0022]

[0023] As shown in the table above, 2205 duplex stainless steel possesses both high yield strength and tensile strength, as well as excellent corrosion resistance, making it more suitable for the support frame 1 of floating photovoltaic pontoons under high salt spray and high impact conditions. For freshwater environments, 304 stainless steel can also be used as the frame material depending on cost requirements. By setting this type of highly corrosion-resistant support frame 1 inside the pontoon, the pontoon can maintain good structural stability when subjected to photovoltaic module loads, wind and wave impact loads, and long-term alternating stress.

[0024] like Figure 2 and Figure 3As shown, the surface composite structure 3 is wrapped around the outside of the pontoon body, which not only constitutes the external protective layer of the pontoon, but also is an important component of the overall structure of the pontoon. In this embodiment, the surface composite structure 3 is formed by the composite curing of polyurethane-polyurea elastomer and fiber reinforcement material, preferably a multi-layer composite structure, which includes, from the outside to the inside, a polyurethane-polyurea elastomer layer 31, a fiber reinforcement layer 32, another polyurethane-polyurea elastomer layer 31, a fiber reinforcement layer 32, and another polyurethane-polyurea elastomer layer 31, thus forming a multi-layer composite structure of "two fabrics and three coatings". The fiber reinforcement material can be one or more of basalt fiber, aramid fiber, carbon fiber, or glass fiber, preferably alkali-free glass fiber cloth, for example, alkali-free glass fiber cloth with a basis weight of 80-160 g / m², preferably 100 g / m², and a thickness of about 0.1 mm can be used as the reinforcement material.

[0025] Furthermore, the polyurethane-polyurea elastomer can be formed using a two-component system, wherein component A may include polyaspartic acid ester, wetting and dispersing agent, defoamer, thixotropic agent, antifouling and antibacterial filler, pigments, dehydrating agent, color powder, ultraviolet absorber and rheology modifier, etc., and component B may be an aliphatic prepolymer system; wherein the antifouling and antibacterial filler may include one or more of nano-sized titanium dioxide and nano-sized zinc oxide.

[0026] Component A can be prepared by the following steps: S10: Add 20 parts of polyaspartic acid ester resin to the reactor, add 0.6 parts of dispersant and 1.0 part of defoamer in sequence at a speed of 500-600 rpm, then slowly add 0.7 parts of thixotropic agent, increase the speed to 800-1000 rpm, and disperse at high speed until a uniform viscous liquid is formed. No obvious particulate matter is detected by film stretching test.

[0027] S20: Then slowly add 5 parts of antifouling and antibacterial filler (nano-grade titanium dioxide and nano-grade zinc oxide) in sequence, increase the rotation speed to 1000-1200 rpm, and disperse at high speed for more than 20 minutes.

[0028] S30: Then slowly add 32.5 parts of pigment and filler, 3 parts of dehydrating agent, 1 part of color powder, and 0.2 parts of ultraviolet absorber in sequence, and disperse at high speed until the fineness of the slurry is ≤50μm.

[0029] S40: Reduce the rotation speed to 500-700 rpm, slowly add the remaining 35 parts of polyaspartic ester resin, 0.5 parts of defoamer and 0.5 parts of rheology modifier, and mix thoroughly.

[0030] S50: Reduce the rotation speed to 400-500 rpm and gradually increase the temperature to 100-120°C. Turn on the vacuum system and maintain a vacuum of -0.095 MPa for more than 100 minutes until the moisture content is <0.05%. After cooling to 60-80°C, obtain component A.

[0031] Component B can be prepared by the following steps: S100: Dehydrate polyols for later use. Dehydrate the polyol components at 100-120°C under a vacuum of -0.095 MPa until the moisture content is <0.05%, then cool them down for later use.

[0032] S200: Nitrogen gas is introduced into a sealed reactor to replace the air. Then, 65.5 parts of isocyanate monomer (HMDI) are added. The temperature is raised to 50-60°C. At a speed of 400-600 rpm, 100 parts of polyol component and an appropriate amount of catalyst are slowly added.

[0033] S300: After the addition is complete, maintain the temperature at 85-90°C for more than 3 hours until the NCO value reaches the design value. Then, cool down to room temperature to obtain component B, and seal it for later use.

[0034] The performance parameters of the polyurethane-polyurea elastomer formed using the above material system, tested according to the relevant standard T / CWA 204-2021, are shown in the table below:

[0035] The data above shows that the polyurethane-polyurea elastomer itself has high strength, high elongation and good resistance to salt water and weathering, making it suitable as a substrate material for the outer layer of pontoons; it also maintains good flexibility in low-temperature environments, which is beneficial for construction and operation in cold northern regions.

[0036] like Figure 3 As shown, based on the aforementioned elastomer, a surface composite structure 3 is formed by combining it with alkali-free glass fiber cloth through a "two-cloth, three-coat" process, which further improves the overall mechanical properties. The performance of this composite surface layer was compared with that of traditional HDPE materials, and the main data are as follows:

[0037] The data above shows that the fiber-reinforced polyurethane-polyurea elastomer composite surface layer is significantly superior to traditional HDPE materials in terms of tensile strength and impact resistance, thus better enhancing the buoy's resistance to wind and wave impacts and foreign object collisions. Simultaneously, the active nano-scale TiO2 and ZnO in the surface layer can also inhibit the attachment of marine microorganisms. According to GB / T 23763-2009 "Evaluation of Antibacterial Properties of Photocatalytic Antibacterial Materials and Products", the antibacterial properties of this example were compared with those of traditional HDPE float material. Test conditions: light source was a 365nm black lamp (UVA); light intensity: 1.0mW / cm²; illumination time: 8 hours; temperature: 25°C±2°C; relative humidity: 90%; test bacteria: (AS 1.90), Staphylococcus aureus (AS 1.89). The antibacterial performance test results showed that under 365nm ultraviolet light irradiation, the surface material achieved an antibacterial rate of over 99% against both Escherichia coli and Staphylococcus aureus, significantly superior to traditional HDPE material. Furthermore, according to GB / T... In the shallow sea immersion test of the antifouling paint sample according to 5370-2007 "Test Method for Antifouling Paint Samples in Shallow Sea", after 12 months, the biological coverage area of ​​the sample in this embodiment was still less than 12%, while the biological coverage of the HDPE lining exceeded 93%, indicating that it has better antibacterial and antifouling capabilities. The above embodiments mainly illustrate the preferred implementation of the surface composite structure 3 of the present invention in terms of material system and comprehensive performance, and do not constitute a limitation on the scope of protection.

[0038] The floating core material is disposed within the internal space enclosed by the surface composite structure 3, and together with the surface composite structure 3 and the supporting frame 1, forms an integrated composite structure. The floating core material is a rigid polyurethane foam formed by molding and foaming, with a density controllable to 150-250 kg / m³, preferably 180-200 kg / m³. The rigid polyurethane foam can be formed by high-pressure foaming of a mixture of polyether and isocyanate components, and liquid flame retardants and flame-retardant fillers can be added to the system to balance flame retardant performance and structural support capacity. Since the supporting frame 1 is embedded inside the floating core material, the core material, after foaming and curing, can provide a covering and supporting effect on the supporting frame 1, thereby combining the supporting frame 1, the surface composite structure 3, and the floating core material into a stable whole. Compared with common low-density EPS or ordinary polyurethane foam, this type of high-density rigid foam core material has superior compressive strength and flexural load-bearing capacity, making it more suitable for long-term bearing of the load of a floating photovoltaic system.

[0039] like Figure 4As shown, the floating photovoltaic pontoon of the present invention can be manufactured using the following method. First, mold and material preparation are performed. The mold can be set according to the expected external dimensions and structural shape of the pontoon, and the inner surface of the mold is pretreated, for example, by uniformly applying a suitable coating agent or release material to facilitate the subsequent molding of the surface composite structure 3 and demolding of the finished product. Simultaneously, the mold temperature can be preheated to 40-50°C. At the same time, the polyurethane-polyurea elastomer components A and B, and fiber reinforcement materials required to form the surface composite structure 3 are prepared, along with the pre-formed support frame 1 and the polyurethane rigid foam raw material required to form the pontoon core material.

[0040] Subsequently, polyurethane-polyurea elastomer is laid on the inner surface of the mold, and fiber reinforcement material is laid to form a surface composite structure 3. Preferably, the surface composite structure 3 can be formed by repeatedly laying polyurethane-polyurea elastomer and laying fiber reinforcement material. In the actual process, polyurethane-polyurea elastomer components A and B are conveyed to a high-speed dynamic mixing head at a mass ratio of 100:73.5-74 under low pressure. The conveying pressure is controlled at 0.5-1 MPa, and the mixing head speed is controlled at 2000-3000 rpm. After being injected into the inner surface of the mold cavity at multiple points, it is quickly brushed and spread. After the first layer of elastomer is surface dry, alkali-free glass fiber cloth is laid and flattened and bonded. Then, elastomer material is injected again and spread to fully impregnate the fiber cloth. The laying and coating process is repeated until a composite surface layer with the preset number of layers and thickness is formed. For the installation area of ​​the pontoon connector 2, the corner transition area, or other nodes where the stress is relatively concentrated, it can be reinforced by adding a layer of elastomer rubber and local reinforcement material. The local reinforcement material can be cut into a ring shape or a trihedral shape to improve the tear resistance and impact resistance of the area.

[0041] like Figure 4 As shown, after the surface composite structure 3 is formed, the pre-formed support frame 1 is placed in a preset position within the mold. When the support frame 1 is placed into the mold, it can be held in the designed position by a positioning structure, a limiting structure, or a temporary fixing method to ensure that after subsequent foaming and molding, the support frame 1 is located within a predetermined area inside the float body and maintains a reasonable distance from the surface composite structure 3. For support frames 1 equipped with connectors 2, an exposed area or corresponding installation position for the connectors 2 can be reserved so that the connectors 2 can be used to connect to the external photovoltaic support structure after molding.

[0042] After the support frame 1 is positioned, polyurethane rigid foam raw material is injected into the mold to form a floating core material. High-pressure foaming is preferred. Polyurethane rigid foam components A and B are added separately to the high-pressure foaming machine's material tanks. The temperature of component A in the material tank can be controlled at 40-60℃, and the temperature of component B in the material tank can be controlled at 25-30℃. During mixing and pouring, the A:B mass ratio can be controlled at approximately 100:75, the mixing pressure controlled at 20-30MPa, and the mixing temperature controlled at 45-50℃. A multi-point pouring method is used to quickly inject the mixed foam material into the lower mold cavity. After pouring to the designed amount, the mold is quickly closed and locked, with the internal pressure controlled at approximately 0.5MPa and the mold temperature controlled at 60-80℃ for molding and curing. Afterward, the mold temperature can be maintained at 70-80℃ for curing for at least 20 minutes. The mold is then opened to obtain the product, which is then placed in an environment of approximately 80℃ for further curing for at least 4 hours, followed by placement at room temperature for at least 24 hours. After molding, the pontoon can be trimmed, polished and partially repaired. For example, the parting line, the location of the connector 2 or the surface defect area can be re-coated or rolled with an appropriate amount of polyurethane-polyurea elastomer to further improve the appearance integrity and surface protection effect.

[0043] like Figure 1 and Figure 4 As shown, after adopting the above-mentioned structural design and manufacturing method, the float does not rely on a single material to undertake all functions. Instead, it achieves comprehensive performance improvement through the division of labor and cooperation of the supporting frame 1, the surface composite structure 3, and the float core material. Among them, the supporting frame 1 mainly provides overall load-bearing and connection support capabilities, the surface composite structure 3 mainly provides external protection, corrosion resistance, weather resistance, and impact resistance enhancement capabilities, and the float core material mainly provides buoyancy and internal support capabilities. The three are integrated into a composite float with strong integrity after molding. According to the embodiments and test data, this type of composite structure has good comprehensive performance in terms of strength, corrosion resistance, wind and wave impact resistance, flame retardancy, and antifouling and antibacterial properties. It is more suitable for water photovoltaic scenarios that are exposed to high humidity, salt spray, ultraviolet radiation, and wind and wave impact environments for a long time, and reduces the problems of aging, cracking, structural loosening, water ingress failure, and frequent maintenance and replacement that are prone to occur in traditional floats.

[0044] The above is only one of the preferred embodiments of the present invention. Those skilled in the art can make corresponding adjustments or substitutions to the specific shape of the support frame 1, the arrangement of the connectors 2, the number of layers of the surface composite structure 3, the type of fiber reinforcement material, the specific composition of the polyurethane-polyurea elastomer, and the density range of the float core material, without departing from the concept of the present invention. Such equivalent changes or conventional modifications should all fall within the protection scope of the present invention.

Claims

1. A floating pontoon for floating photovoltaic applications, characterized in that, Includes a pontoon body, the pontoon body comprising: A support frame is installed inside the pontoon body. The support frame is made of highly corrosion-resistant metal material and is provided with connectors for connecting to external structures. A surface composite structure is provided on the outside of the float body. The surface composite structure is formed by the composite curing of polyurethane-polyurea elastomer and fiber reinforcement material. The core material is disposed within the internal space formed by the surface composite structure, and the core material is rigid polyurethane foam. The supporting frame is embedded in the core material and together with the surface composite structure and the core material, it forms an integrated composite pontoon structure.

2. The floating pontoon for waterborne photovoltaic applications according to claim 1, characterized in that: The highly corrosion-resistant metal material is one of 304 stainless steel, 316 stainless steel, 316L stainless steel, 5-series marine-grade aluminum alloy, or 2205 duplex stainless steel. The surface composite structure is a multi-layer composite structure, which includes, from the outside to the inside, a polyurethane-polyurea elastomer layer, a fiber reinforcement layer, a polyurethane-polyurea elastomer layer, a fiber reinforcement layer, and a polyurethane-polyurea elastomer layer. The fiber reinforcement material is one or more of basalt fiber, aramid fiber, carbon fiber or glass fiber; The core material is rigid polyurethane foam formed by molding foaming, and the density of the rigid polyurethane foam is 150-250 kg / m³.

3. A method for preparing a floating photovoltaic pontoon as described in claim 1 or 2, characterized in that, Includes the following steps: S1. Prepare the molds and materials; S2. Polyurethane-polyurea elastomer is laid on the inner surface of the mold, and fiber reinforcement material is laid on it, so that the polyurethane-polyurea elastomer and fiber reinforcement material are combined to form a surface composite structure. S3. After the surface composite structure is formed, the pre-formed support frame is placed in a preset position inside the mold. S4. Inject rigid polyurethane foam raw material into the mold to allow it to foam and form the core material; S5. The mold is closed and cured, so that the surface composite structure, the supporting frame and the core material are integrally formed to obtain the floating pontoon for water photovoltaic.

4. The method for preparing a floating photovoltaic pontoon according to claim 3, characterized in that: In step S1, a polyurethane special coating agent is applied to the inner surface of the float mold and dried. Before the surface composite structure is prepared, the mold temperature is raised to 40-50℃. The prepared polyurethane-polyurea elastomer components A and B are added to the material tank of the two-component polyurethane casting machine, and the temperature of the material tank is controlled at 40-60℃. Vacuum degassing is carried out for later use. At the same time, the fiber reinforcement material is cut according to the mold size for later use. In step S2, components A and B are transported to a high-speed dynamic mixing head at a low pressure according to a mass ratio of A to B of 100:73.5-74. The transport pressure is 0.5-1MPa and the mixing head speed is 2000-3000 rpm. The components are then injected into the inner surface of the mold at multiple points and spread evenly.

5. The method for preparing a floating photovoltaic pontoon according to claim 4, characterized in that: In step S2, after the first layer of polyurethane-polyurea elastomer is surface dry, the fiber reinforcement material is laid on the adhesive film and flattened by rollers and brushes so that the fiber reinforcement material and polyurethane-polyurea elastomer are tightly bonded together. Then, inject polyurethane-polyurea elastomer compound at multiple points and spread it evenly to impregnate the fiber reinforcement material. Repeat this process until the specified number of layers and thickness are reached. At the node positions corresponding to the connectors on the pontoon, reinforcement is achieved by laying an additional layer of polyurethane-polyurea elastomer and fiber reinforcement material, with the fiber reinforcement material cut into a ring shape or a trihedral shape.

6. The method for preparing a floating photovoltaic pontoon according to claim 3, characterized in that: In step S4, polyurethane rigid foam components A and B are added to the material tanks of the high-pressure foaming machine, and the temperature of component A in the material tank is controlled at 40-60℃ and the temperature of component B in the material tank is controlled at 25-30℃. Turn on the high-pressure foaming machine and mix components A and B at a mass ratio of 100:

75. The mixing pressure is 20-30MPa and the mixing temperature is 45-50℃. The mixed foaming material is then injected into the lower mold cavity of the mold using a multi-point pouring method. In step S5, after pouring to the designed amount, the mold is closed and locked. The internal pressure is controlled at 0.5MPa and the mold temperature is controlled at 60-80℃ for molding and curing.

7. The method for preparing a floating photovoltaic pontoon according to claim 6, characterized in that: After molding and curing, maintain the mold temperature at 70-80℃ and cure for more than 20 minutes before opening the mold to obtain the product; Place the product in an 80℃ environment for more than 4 hours to mature, and then leave it at room temperature for more than 24 hours. The product is then trimmed, and the parting line, connector positions, and surface defects are sanded. Polyurethane-polyurea elastomer is then applied to the corresponding areas by brushing or rolling, and the finished product is obtained after curing.

8. A polyurethane-polyurea elastomer material for use in the floating photovoltaic pontoon of claim 1 or 2, characterized in that: The polyurethane-polyurea elastomer material is made of component A and component B; Component A includes polyaspartic acid ester, active antibacterial filler, and functional additives; Component B is an aliphatic prepolymer with an NCO% of 8-15%, and is prepared by mixing and reacting IPDI or HMDI with polyol resins PTMG and PPG. The R value of the reaction between components A and B is the isocyanate index n(—NCO) / n(—NH) = 1-1.2, and the mass ratio of components A to B is 100:73.

5.

9. The polyurethane-polyurea elastomer material according to claim 8, characterized in that: Component A, by weight, comprises: 45-65 parts of polyaspartic acid ester, 0.3-0.8 parts of wetting and dispersing agent, 0.6-2 parts of defoamer, 0.5-1 parts of thixotropic agent, 2-2.5 parts of nano-grade rutile titanium dioxide, 2-3 parts of nano-grade zinc oxide, 20-45 parts of pigments and fillers, 3-8 parts of dehydrating agent, 0-2 parts of color powder, 0.2-0.5 parts of ultraviolet absorber, and 0.3-1 parts of rheology modifier; The B component comprises, by mass, 100 parts of polyol resin, 50-80 parts of aliphatic isocyanate monomer, and a catalyst.

10. A rigid polyurethane foam material for use in the floating photovoltaic pontoon as described in claim 1 or 2, characterized in that: The polyurethane rigid foam material is formed by the reaction and foaming of component A and component B. Component A comprises, by weight, 80-95 parts of polyether, 5-20 parts of phthalic anhydride polyester polyol, 0.2-0.8 parts of crosslinking agent, 0.5-1.2 parts of N,N-dimethylcyclohexylamine, 1-2.5 parts of foam stabilizer, 8-12 parts of physical foaming agent, 0.2-1.0 parts of water, 15-30 parts of liquid flame retardant, and 20-30 parts of flame retardant filler; Component B is polyphenyl polymethylene polyisocyanate; The mass ratio of component A to component B is 158:115-120.

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