Sandwich composite building template and preparation method thereof

Abstract

The invention discloses a sandwich composite building template and a preparation method thereof, and belongs to the technical field of composite building template materials.A surface layer of the sandwich composite building template is prepared from glass fibers recycled from blades of a wind driven generator, high-density polyethylene, a compatilizer, a first lubricant and a first nucleating agent as raw materials; preparing a surface layer of the sandwich composite building template by using the crushed particles of the blades of the wind driven generator, polypropylene, a toughening agent, a second lubricant, a flame retardant, an antioxidant, an ultraviolet absorbent and a second nucleating agent as raw materials; the method comprises the following steps: mixing recycled wind driven generator blade broken particles with polypropylene to obtain a core layer, filling polyethylene with glass fibers recycled from wind driven generator blades to obtain a surface layer, carrying out hot pressing for composite molding, and controlling the thickness to obtain the sandwich composite building template of the wind driven generator blade recycled material. The sandwich composite building template has the advantages of light weight, high deformation resistance, high strength, high modulus and low preparation cost.

Description

Technical Field

[0001] The present invention relates to the technical field of composite building formwork materials, and particularly relates to a sandwich composite building formwork and a preparation method thereof. Background Art

[0002] A building formwork is a model tool used in building construction to form the structural shape and dimensions when pouring concrete. It can shape the concrete components according to the design requirements, such as columns, beams, slabs, walls, etc., and ensure their accurate dimensions. The building formwork can bear the weight and side pressure of concrete pouring and vibration as well as construction loads, ensuring construction safety and component quality. Building formworks include wooden formworks, steel formworks, plastic formworks, and aluminum alloy formworks.

[0003] The rapid development of the construction industry has promoted continuous innovation in the material field. As a commonly used turnover material at the construction site, building formworks have problems such as large usage and high loss rates. Traditional wooden formworks or steel formworks not only have low turnover rates but also high costs. Plastic formworks have the advantages of low price, many turnover times, and easy processing, but their mechanical properties far cannot meet the requirements of building formworks. Summary of the Invention

[0004] In view of the above problems, the present invention provides a sandwich composite building formwork and a preparation method thereof, effectively avoiding the disadvantages of high costs caused by using wooden formworks or steel formworks; solving the technical problem that plastic formworks have poor mechanical properties and cannot meet the requirements of building formworks. The present invention prepares a high-strength and high-modulus glass fiber cloth as the surface layer by filling recycled glass fibers from wind turbine blades into high-density polyethylene, and uses a composite material of recycled wind turbine blade crushed particles and polypropylene as the core layer of the composite board, not only realizing the efficient recycling of wind turbine blades, but also providing a building formwork with excellent performance and environmental protection for the construction industry.

[0005] The first object of the present invention is to provide a sandwich composite building formwork, including a surface layer and a core layer, and the sandwich composite building formwork is stacked in the order of surface layer - core layer - surface layer.

[0006] The surface layer is made of the following raw materials by mass fraction: 10% - 40% of recycled glass fibers, 50% - 75% of polyethylene, 6% - 11% of compatibilizer, 2% - 4% of the first lubricant, and 0.1% - 0.3% of the first nucleating agent, totaling 100%.

[0007] The core layer is made of raw materials with the following mass fractions: 20% - 40% crushed particles, 60% - 80% polypropylene, 1% - 3% toughening agent, 0.2% - 0.5% second lubricant, 0.2% - 0.7% flame retardant, 0.2% - 0.5% antioxidant, 0.2% - 0.5% ultraviolet absorber, and 0.3% - 1.2% second nucleating agent, with a total of 100%.

[0008] The crushed particles contain glass fiber and carbon fiber.

[0009] As a preferred embodiment, the recycled glass fiber has a diameter of 17μm and a length of 1mm - 3mm.

[0010] As a preferred embodiment, the melt flow rate of the polypropylene is 20g / 10min and the grade is BF970MO; the melt flow rate of the polyethylene is 14g / 10min and the density is 0.955g / cm 3 , and the grade is CH1402.

[0011] As a preferred embodiment, the first lubricant is pentaerythritol stearate, and the second lubricant is composed of calcium stearate with a mass concentration of 0.2wt% - 0.4wt% and zinc stearate with a mass concentration of 0.1wt% - 0.3wt% in a mass ratio of 3:2; the first nucleating agent is a PE nucleating agent with the grade of HY - 9902, and the second nucleating agent is a PP nucleating agent with the grade of JYN - 611.

[0012] As a preferred embodiment, the toughening agent is EVA type 565, hydrogenated styrene - butadiene - styrene block copolymer, ethylene - propylene rubber, ethylene - octene copolymer, or ethylene - propylene - diene monomer rubber, the compatibilizer is maleic anhydride grafted polyethylene, and the ultraviolet absorber is UV329.

[0013] As a preferred embodiment, the flame retardant is composed of magnesium hydroxide with a mass concentration of 0.1wt% - 0.3wt% and aluminum hydroxide with a mass concentration of 0.2wt% - 0.4wt% in a mass ratio of 1:1; the antioxidant is composed of type 1010 with a mass concentration of 0.1wt% - 0.3wt%, type 168 with a mass concentration of 0.1wt% - 0.3wt%, and type 1024 with a mass concentration of 0.05wt% - 0.1wt% in a mass ratio of 1:2:2.

[0014] The second object of the present invention is to provide a preparation method of the above - mentioned sandwich composite building formwork, which includes the following steps: Weigh each raw material of the surface layer and the core layer according to the mass fractions of the above - mentioned raw materials.

[0015] Mix broken particles, polypropylene, toughening agent, lubricant, flame retardant, antioxidant, ultraviolet absorber and second nucleating agent, heat the mixture to 175°C - 180°C to plasticize it into a dough-like material, extrude and granulate to obtain composite material particles, and put the composite material particles into the template production line to obtain the core layer.

[0016] Mix the recycled glass fiber evenly with lubricant, compatibilizer, first nucleating agent and polyethylene, extrude and granulate, and perform hot pressing at 165°C - 175°C for the first time to obtain the surface layer.

[0017] Stack them in the order of surface layer - core layer - surface layer, perform secondary hot pressing at 130°C - 190°C and control the thickness to obtain the sandwich composite building formwork.

[0018] As a preferred embodiment, the thickness of the core layer is 15 mm - 18 mm, and the thickness of the surface layer is 0.5 mm - 1 mm.

[0019] As a preferred embodiment, the thickness control is controlled by a thickness control module. During secondary hot pressing, the thickness of the heating section is 16.5 mm - 20.5 mm, and the thickness of the cooling section is 15.5 mm - 19.5 mm.

[0020] As a preferred embodiment, the pressure for the first hot pressing is 10 MPa and the time is 15 min.

[0021] Compared with the prior art, the beneficial effects of the present invention are as follows: The present invention provides a sandwich composite building formwork and its preparation method. The surface layer of the sandwich composite building formwork is made of recycled glass fiber, high-density polyethylene, compatibilizer, first lubricant and first nucleating agent; the surface layer of the sandwich composite building formwork is made of broken particles, polypropylene, toughening agent, second lubricant, flame retardant, antioxidant, ultraviolet absorber and second nucleating agent; the core layer is obtained by mixing broken particles and polypropylene. Since the recycled broken particles contain a large amount of glass fiber and carbon fiber, when they are blended with polypropylene, the mechanical properties of the core layer are greatly improved, and the cost is effectively reduced at the same time; the recycled glass fiber is filled into polyethylene to obtain the surface layer, and the recycled glass fiber is doped into polyethylene, which greatly improves the mechanical properties of the surface layer. Then, through hot pressing and composite molding, the polypropylene of the core layer is fused and adhered to the polyethylene of the surface layer, thereby improving the interfacial bonding force between the surface layer and the core layer of the sandwich composite building formwork, and obtaining a sandwich composite building formwork with better mechanical properties. The sandwich composite building formwork obtained by the present invention has the advantages of light weight, strong anti-deformation ability, high strength, high modulus and low preparation cost. Specific embodiments

[0022] In order to enable those skilled in the art to better understand and implement the technical solution of the present invention, the present invention will be further described below in conjunction with specific embodiments, but the exemplified embodiments shall not be construed as limiting the present invention. The following test methods and detection methods are all conventional methods unless otherwise specified; the reagents and raw materials are all commercially available unless otherwise specified.

[0023] As a commonly used turnover material at the construction site, building formwork has problems such as large consumption and high loss rate. Wooden formwork or steel formwork not only has a low turnover rate, but also has problems of resource waste, high cost, and poor acid and alkali corrosion resistance. Plastic formwork has the advantages of low price, many turnover times, and easy processing, but its mechanical properties far cannot meet the requirements of building formwork. Based on the above problems, the present invention provides a sandwich composite building formwork and its preparation method.

[0024] The technical solution of the present invention will be described in detail below.

[0025] The present invention first provides a first object of the present invention is to provide a sandwich composite building formwork, including a surface layer and a core layer, and the sandwich composite building formwork is stacked in the order of surface layer - core layer - surface layer.

[0026] The surface layer is made of the following raw materials by mass fraction: 10% - 40% of glass fibers recycled from wind turbine blades with a diameter of 17μm and a length of 1mm - 3mm, 50% - 75% of polyethylene, 6% - 11% of compatibilizer, 2% - 4% of the first lubricant, and 0.1% - 0.3% of the first nucleating agent, totaling 100%.

[0027] The core layer is made of the following raw materials by mass fraction: 20% - 40% of crushed particles of wind turbine blades, 60% - 80% of polypropylene, 1% - 3% of toughening agent, 0.2% - 0.5% of the second lubricant, 0.2% - 0.7% of flame retardant, 0.2% - 0.5% of antioxidant, 0.2% - 0.5% of ultraviolet absorber, and 0.3% - 1.2% of the second nucleating agent, totaling 100%.

[0028] In the above technical solution, the core layer is obtained by mixing the recycled crushed particles of wind turbine blades with polypropylene. Since the recycled crushed particles of wind turbine blades contain a large amount of glass fibers and carbon fibers, when they are blended with polypropylene, the mechanical properties of the core layer are greatly improved, and the cost is effectively reduced at the same time; the surface layer is obtained by filling the glass fibers recycled from wind turbine blades into polyethylene. The recycled glass fibers are doped into polyethylene, which greatly improves the mechanical properties of the surface layer. Then, through hot pressing and composite molding, the polypropylene in the core layer is fused and adhered to the polyethylene in the surface layer, thereby improving the interfacial bonding force between the surface layer and the core layer of the sandwich composite building formwork.

[0029] It should be noted that the melt flow rate of the polypropylene is 20 g / 10 min, and the grade is BF970MO; the melt flow rate of the polyethylene is 14 g / 10 min, and the density is 0.955 g / cm 3 , and the grade is CH1402; the first lubricant is pentaerythritol stearate, and the second lubricant is composed of 0.2 wt% - 0.4 wt% of calcium stearate and 0.1 wt% - 0.3 wt% of zinc stearate according to a mass ratio of 3:2; the first nucleating agent is a PE nucleating agent, and the grade is: HY-9902, the second nucleating agent is a PP nucleating agent, and the grade is: JYN-611; the toughening agent is 565-type EVA, hydrogenated styrene-butadiene-styrene block copolymer, ethylene-propylene rubber, ethylene-octene copolymer or ethylene-propylene-diene monomer rubber, the compatibilizer is maleic anhydride grafted polyethylene, and the ultraviolet absorber is UV329.

[0030] It should be emphasized that the flame retardant is composed of 0.1 wt% - 0.3 wt% of magnesium hydroxide and 0.2 wt% - 0.4 wt% of aluminum hydroxide according to a mass ratio of 1:1; the antioxidant is composed of 0.1 wt% - 0.3 wt% of type 1010, 0.1 wt% - 0.3 wt% of type 168, and 0.05 wt% - 0.1 wt% of type 1024 according to a mass ratio of 1:2:2.

[0031] The second object of the present invention is to provide a preparation method of the above sandwich composite building formwork, including the following steps: Weigh each raw material of the surface layer and the core layer according to the mass fraction of the above raw materials.

[0032] Mix the broken particles of the wind turbine blade, polypropylene, toughening agent, lubricant, flame retardant, antioxidant, ultraviolet absorber and the second nucleating agent, heat the mixture to 175°C - 180°C to plasticize it into a dough-like material, extrude and granulate to obtain composite material particles, and put the composite material particles into the formwork production line to obtain the core layer; if the heating temperature is too low, lower than 175°C, the polypropylene cannot be fully melted and mixed evenly, affecting the performance of the core layer board; if the temperature is too high, higher than 180°C, it will cause the degradation of polypropylene, reducing the performance of the material and even generating harmful gases.

[0033] Mix the glass fiber recycled from wind turbine blades evenly with lubricant, compatibilizer, first nucleating agent and polyethylene, extrude and pelletize, and conduct a one-time hot pressing at 165°C to 175°C under a pressure of 10 MPa for 15 minutes to obtain the surface layer; if the heating temperature is too low, below 165°C, polyethylene cannot be fully melted and mixed evenly, affecting the performance of the surface layer board; while if the temperature is too high, above 175°C, it will cause polyethylene degradation, reducing the performance of the material and even generating harmful gases.

[0034] Stack them in the order of surface layer - core layer - surface layer, conduct a secondary hot pressing at 130°C to 190°C and control the thickness to obtain a sandwich composite building formwork.

[0035] In order to make the size of the prepared sandwich composite board reach the standard size for application, when hot pressing and forming, control the thickness of the core layer to be 15 mm to 18 mm, and the thickness of the surface layer to be 0.5 mm to 1 mm.

[0036] In order to further improve the bonding force between the core layer and the surface layer, the thickness control is controlled by a thickness control module. During the secondary hot pressing, the thickness of the heating section is 16.5 mm to 20.5 mm, and the thickness of the cooling section is 15.5 mm to 19.5 mm. It should be noted that the main reason for the thickness of the heating section being higher than that of the cooling section is to prevent large deformation of the core layer caused by hot pressing, and the purpose of reducing the thickness of the cooling section is to make the core layer and the surface layer fit more closely and have better bonding force.

[0037] The following specifically describes the content of the present invention through the following examples and comparative examples.

[0038] Example 1 A sandwich composite building formwork includes a surface layer and a core layer; The surface layer is made of the following raw materials by mass fraction: 10% of glass fiber recycled from wind turbine blades, 75% of polyethylene with a density of 0.955 g / cm 3 The melt flow rate of the polyethylene is 14 g / 10 min, the grade is CH1402, 11% of compatibilizer, 3.7% of first lubricant pentaerythritol stearate and 0.3% of first nucleating agent; the first nucleating agent is a PE nucleating agent, and the grade is: HY-9902.

[0039] The core layer is made of the following raw materials by mass fraction: 20% of crushed particles of wind turbine blades, 76% of polypropylene with a melt flow rate of 20 g / 10 min, the grade is BF970MO, 2% of toughening agent, 0.3% of second lubricant, 0.5% of flame retardant, 0.4% of antioxidant, 0.5% of ultraviolet absorber UV329, 0.3% of second nucleating agent.

[0040] The toughening agent is EVA of type 565; the second lubricant is composed of 0.3 wt% of calcium stearate and 0.2 wt% of zinc stearate according to a mass ratio of 3:2; the second nucleating agent is a PP nucleating agent with the brand number: JYN-611. The flame retardant is composed of 0.2 wt% of magnesium hydroxide and 0.3 wt% of aluminum hydroxide according to a mass ratio of 1:1; the antioxidant is composed of 0.2 wt% of type 1010, 0.2 wt% of type 168, and 0.08 wt% of type 1024 according to a mass ratio of 1:2:2.

[0041] The preparation method of the above sandwich composite building formwork includes the following steps: Weigh each raw material of the surface layer and the core layer according to the mass fraction of the above raw materials.

[0042] Mix the broken particles of wind turbine blades, polypropylene, toughening agent, lubricant, flame retardant, antioxidant, ultraviolet absorber, and second nucleating agent to obtain a mixture. Put the mixture into a mixer and heat it to 180 °C to plasticize it into a dough-like material, then extrude and pelletize to obtain composite material pellets. Put the composite material pellets into the formwork production line to obtain a core layer with a thickness of 15 mm.

[0043] Mix the glass fiber recovered from wind turbine blades, lubricant, compatibilizer, first nucleating agent, and polyethylene evenly, extrude and pelletize, and hot press at 170 °C and 10 MPa for 15 min to obtain a surface layer with a thickness of 1 mm.

[0044] Stack them in the order of surface layer - core layer - surface layer, and hot press at 160 °C for the second time and control the thickness to 17 mm to obtain the sandwich composite building formwork.

[0045] Example 2 A sandwich composite building formwork includes a surface layer and a core layer.

[0046] The surface layer is made of the following raw materials by mass fraction: 20% of the glass fiber recovered from wind turbine blades, 66% of polyethylene with a density of 0.955 g / cm 3 The melt flow rate of the polyethylene is 14 g / 10 min, and the brand number is CH1402, 10% of compatibilizer, 3.7% of the first lubricant pentaerythritol stearate, and 0.3% of the first nucleating agent; the first nucleating agent is a PE nucleating agent with the brand number: HY-9902.

[0047] The core layer is made of the following raw materials by mass fraction: 20% of the broken particles of wind turbine blades, 76% of polypropylene with a melt flow rate of 20 g / 10 min, the brand number is BF970MO, 2% of toughening agent, 0.3% of the second lubricant, 0.5% of flame retardant, 0.4% of antioxidant, 0.5% of ultraviolet absorber UV329, and 0.3% of the second nucleating agent.

[0048] The toughening agent is EVA of type 565; the second lubricant is composed of 0.2 wt% of calcium stearate and 0.1 wt% of zinc stearate according to a mass ratio of 3:2; the second nucleating agent is a PP nucleating agent with the brand number: JYN-611. The flame retardant is composed of 0.1 wt% of magnesium hydroxide and 0.2 wt% of aluminum hydroxide according to a mass ratio of 1:1; the antioxidant is composed of 0.1 wt% of type 1010, 0.1 wt% of type 168, and 0.05 wt% of type 1024 according to a mass ratio of 1:2:2.

[0049] The preparation method of the above sandwich composite building formwork includes the following steps: Weigh each raw material of the surface layer and the core layer according to the mass fraction of the above raw materials.

[0050] Mix the broken particles of wind turbine blades, polypropylene, toughening agent, lubricant, flame retardant, antioxidant, ultraviolet absorber, and second nucleating agent to obtain a mixture. Put the mixture into a mixer and heat it to 180 °C to plasticize it into a dough-like material, then extrude and pelletize to obtain composite material pellets. Put the composite material pellets into the formwork production line to obtain a core layer with a thickness of 15 mm.

[0051] Mix the glass fiber recovered from wind turbine blades, lubricant, compatibilizer, first nucleating agent, and polyethylene evenly, then extrude and pelletize. At 170 °C and 10 MPa, hot press for 15 min for the first time to obtain a surface layer with a thickness of 1 mm.

[0052] Stack them in the order of surface layer - core layer - surface layer, and hot press for the second time at 160 °C and control the thickness to be 17 mm to obtain the sandwich composite building formwork.

[0053] Example 3 A sandwich composite building formwork includes a surface layer and a core layer.

[0054] The surface layer is made of the following raw materials by mass fraction: 30% of the glass fiber recovered from wind turbine blades, 58% of polyethylene with a density of 0.955 g / cm 3 The melt flow rate of the polyethylene is 14 g / 10 min, and the brand number is CH1402, 8% of compatibilizer, 3.7% of the first lubricant pentaerythritol stearate, and 0.3% of the first nucleating agent; the first nucleating agent is a PE nucleating agent with the brand number: HY-9902.

[0055] The core layer is made of raw materials with the following mass fractions: 20% of broken particles of wind turbine blades, 76% of polypropylene with a melt flow rate of 20 g / 10 min, 2% of toughening agent with the brand number BF970MO, 0.3% of second lubricant, 0.5% of flame retardant, 0.4% of antioxidant, 0.5% of ultraviolet absorber UV329, and 0.3% of second nucleating agent.

[0056] The toughening agent is EVA of type 565; the second lubricant is composed of 0.4 wt% of calcium stearate and 0.3 wt% of zinc stearate according to the mass ratio of 3:2; the second nucleating agent is a PP nucleating agent with the brand number: JYN - 611. The flame retardant is composed of 0.3 wt% of magnesium hydroxide and 0.4 wt% of aluminum hydroxide according to the mass ratio of 1:1; the antioxidant is composed of 0.3 wt% of type 1010, 0.3 wt% of type 168, and 0.1 wt% of type 1024 according to the mass ratio of 1:2:2.

[0057] The preparation method of the above sandwich composite building formwork includes the following steps: Weigh each raw material of the surface layer and the core layer according to the mass fractions of the above raw materials.

[0058] Mix the broken particles of wind turbine blades, polypropylene, toughening agent, lubricant, flame retardant, antioxidant, ultraviolet absorber, and second nucleating agent to obtain a mixture. Put the mixture into a mixer and heat it to 180 °C to plasticize it into a dough - like material, then extrude and granulate to obtain composite material particles. Put the composite material particles into the formwork production line to obtain a core layer with a thickness of 15 mm.

[0059] Mix the glass fiber recovered from wind turbine blades, lubricant, compatibilizer, first nucleating agent, and polyethylene evenly, then extrude and granulate. At 170 °C and 10 MPa, hot - press for 15 min for the first time to obtain a surface layer with a thickness of 1 mm.

[0060] Stack them in the order of surface layer - core layer - surface layer, and hot - press for the second time at 160 °C and control the thickness to be 17 mm to obtain the sandwich composite building formwork.

[0061] Example 4 A sandwich composite building formwork includes a surface layer and a core layer.

[0062] The surface layer is made of raw materials with the following mass fractions: 40% of glass fiber recovered from wind turbine blades with a diameter of 17 μm and a length of 1 mm - 3 mm, and polyethylene with a density of 0.955 g / cm 350% of polyethylene, the melt flow rate of the polyethylene is 14 g / 10 min, the grade is CH1402, 6% of compatibilizer, 3.7% of the first lubricant pentaerythritol stearate and 0.3% of the first nucleating agent; the first nucleating agent is a PE nucleating agent, and the grade is: HY-9902.

[0063] The core layer is made of the following raw materials by mass fraction: 20% of broken particles of wind turbine blades, 76% of polypropylene with a melt flow rate of 20 g / 10 min, the grade is BF970MO, 2% of toughening agent, 0.3% of the second lubricant, 0.5% of flame retardant, 0.4% of antioxidant, 0.5% of ultraviolet absorber UV329, 0.3% of the second nucleating agent.

[0064] The toughening agent is EVA of type 565; the second lubricant is composed of 0.2 wt% of calcium stearate and 0.3 wt% of zinc stearate according to the mass ratio of 3:2; the second nucleating agent is a PP nucleating agent, and the grade is: JYN-611. The flame retardant is composed of 0.2 wt% of magnesium hydroxide and 0.4 wt% of aluminum hydroxide according to the mass ratio of 1:1; the antioxidant is composed of 0.2 wt% of type 1010, 0.3 wt% of type 168 and 0.05 wt% of type 1024 according to the mass ratio of 1:2:2.

[0065] The preparation method of the above sandwich composite building formwork includes the following steps: Weigh each raw material of the surface layer and the core layer according to the mass fraction of the above raw materials.

[0066] Mix the broken particles of wind turbine blades, polypropylene, toughening agent, lubricant, flame retardant, antioxidant, ultraviolet absorber and the second nucleating agent to obtain a mixture. Put the mixture into a mixer and heat it to 180 °C to plasticize it into a mass material, extrude and granulate to obtain composite material particles. Put the composite material particles into the formwork production line to obtain a core layer with a thickness of 15 mm.

[0067] Mix the glass fiber recovered from wind turbine blades with the lubricant, compatibilizer, first nucleating agent and polyethylene evenly, extrude and granulate, and hot press it at 170 °C and 10 MPa for 15 min to obtain a surface layer with a thickness of 1 mm.

[0068] Stack them in the order of surface layer - core layer - surface layer, and hot press them at 160 °C for the second time and control the thickness to be 17 mm to obtain the sandwich composite building formwork.

[0069] Example 5 A sandwich composite building formwork, including a surface layer and a core layer.

[0070] The surface layer is made of raw materials with the following mass fractions: 26% of glass fibers recovered from wind turbine blades with a diameter of 17 μm and a length of 1 mm to 3 mm, 62% of polyethylene with a density of 0.955 g / cm 3 , the melt flow rate of the polyethylene is 14 g / 10 min, the grade is CH1402, 7.8% of compatibilizer, 4.0% of the first lubricant pentaerythritol stearate, and 0.2% of the first nucleating agent; the first nucleating agent is a PE nucleating agent, and the grade is: HY-9902.

[0071] The core layer is made of raw materials with the following mass fractions: 20% of crushed particles of wind turbine blades, 76% of polypropylene with a melt flow rate of 20 g / 10 min, the grade is BF970MO, 2% of toughening agent, 0.3% of the second lubricant, 0.5% of flame retardant, 0.4% of antioxidant, 0.5% of ultraviolet absorber UV329, 0.3% of the second nucleating agent, totaling 100%.

[0072] The toughening agent is 565-type EVA; the second lubricant is composed of 0.4 wt% of calcium stearate and 0.1 wt% of zinc stearate according to a mass ratio of 3:2; the second nucleating agent is a PP nucleating agent, and the grade is: JYN-611. The flame retardant is composed of 0.3 wt% of magnesium hydroxide and 0.3 wt% of aluminum hydroxide according to a mass ratio of 1:1; the antioxidant is composed of 0.3 wt% of type 1010, 0.1 wt% of type 168, and 0.1 wt% of type 1024 according to a mass ratio of 1:2:2.

[0073] The preparation method of the above sandwich composite building formwork includes the following steps: Weigh each raw material of the surface layer and the core layer according to the mass fractions of the above raw materials; Mix the crushed particles of wind turbine blades, polypropylene, toughening agent, lubricant, flame retardant, antioxidant, ultraviolet absorber, and the second nucleating agent to obtain a mixture. Put the mixture into a mixer and heat it to 175 °C to plasticize it into a dough-like material, extrude and pelletize it to obtain composite material pellets. Put the composite material pellets into the formwork production line to obtain a core layer with a thickness of 18 mm.

[0074] Mix the glass fibers recovered from wind turbine blades with the lubricant, compatibilizer, the first nucleating agent, and polyethylene evenly, extrude and pelletize it, and perform a primary hot pressing at 165 °C and 10 MPa for 15 min to obtain a surface layer with a thickness of 0.5 mm.

[0075] Stack them in the order of surface layer - core layer - surface layer, perform a secondary hot pressing at 190 °C and control the thickness to be 17 mm to obtain the sandwich composite building formwork.

[0076] Example 6 A sandwich composite building formwork, comprising a surface layer and a core layer.

[0077] The surface layer is made of raw materials with the following mass fractions: 35% of glass fibers recovered from wind turbine blades with a diameter of 17 μm and a length of 1 mm to 3 mm, 53% of polyethylene with a density of 0.955 g / cm 3 ³, the melt flow rate of the polyethylene is 14 g / 10 min, the grade is CH1402, 9.9% of compatibilizer, 2.0% of the first lubricant pentaerythritol stearate, and 0.1% of the first nucleating agent; the first nucleating agent is a PE nucleating agent, and the grade is: HY-9902.

[0078] The core layer is made of raw materials with the following mass fractions: 20% of crushed particles of wind turbine blades, 76% of polypropylene with a melt flow rate of 20 g / 10 min, the grade is BF970MO, 2% of toughening agent, 0.3% of second lubricant, 0.5% of flame retardant, 0.4% of antioxidant, 0.5% of ultraviolet absorber UV329, 0.3% of second nucleating agent, totaling 100%.

[0079] The toughening agent is 565-type EVA; the second lubricant is composed of 0.3 wt% of calcium stearate and 0.2 wt% of zinc stearate according to a mass ratio of 3:2; the second nucleating agent is a PP nucleating agent, and the grade is: JYN-611. The flame retardant is composed of 0.3 wt% of magnesium hydroxide and 0.2 wt% of aluminum hydroxide according to a mass ratio of 1:1; the antioxidant is composed of 0.2 wt% of type 1010, 0.1 wt% of type 168, and 0.06 wt% of type 1024 according to a mass ratio of 1:2:2.

[0080] The preparation method of the above sandwich composite building formwork includes the following steps: Weigh each raw material of the surface layer and the core layer according to the mass fractions of the above raw materials.

[0081] Mix the crushed particles of wind turbine blades, polypropylene, toughening agent, lubricant, flame retardant, antioxidant, ultraviolet absorber, and second nucleating agent to obtain a mixture. Put the mixture into a mixer and heat it to 178 °C to plasticize it into a dough-like material, then extrude and granulate to obtain composite material particles. Put the composite material particles into the formwork production line to obtain a core layer with a thickness of 16 mm.

[0082] Mix the glass fibers recovered from wind turbine blades with the lubricant, compatibilizer, first nucleating agent, and polyethylene evenly, then extrude and granulate, and perform a one-time hot pressing at 175 °C and 10 MPa for 15 min to obtain a surface layer with a thickness of 1 mm.

[0083] Stack them in the order of surface layer - core layer - surface layer, perform secondary hot pressing at 130 °C and control the thickness to 17 mm to obtain a sandwich composite building formwork.

[0084] To further illustrate the effects of the present invention, the present invention also sets a comparative example as follows: Comparative Example 1 Compared with Example 1, the difference is that the mass fraction of the glass fiber recycled from wind turbine blades is decreased from 10% to 5%, and at the same time, the mass fraction of the polyethylene with a density of 0.955 g / cm 3 is increased from 75% to 80%.

[0085] A sandwich composite building formwork includes a surface layer and a core layer.

[0086] The surface layer is made of the following raw materials by mass fraction: 5% of the glass fiber recycled from wind turbine blades, 80% of the polyethylene with a density of 0.955 g / cm 3 The melt flow rate of the polyethylene is 14 g / 10 min, the grade is CH1402, 11% of compatibilizer, 3.7% of the first lubricant pentaerythritol stearate, and 0.3% of the first nucleating agent; the first nucleating agent is a PE nucleating agent, and the grade is: HY-9902.

[0087] The core layer is made of the following raw materials by mass fraction: 20% of the crushed particles of wind turbine blades, 76% of the polypropylene with a melt flow rate of 20 g / 10 min, the grade is BF970MO, 2% of toughening agent, 0.3% of the second lubricant, 0.5% of flame retardant, 0.4% of antioxidant, 0.5% of ultraviolet absorber UV329, and 0.3% of the second nucleating agent.

[0088] The toughening agent is 565-type EVA; the second lubricant is composed of 0.2 wt% - 0.4 wt% of calcium stearate and 0.1 wt% - 0.3 wt% of zinc stearate; the second nucleating agent is a PP nucleating agent, and the grade is: JYN-611. The flame retardant is composed of 0.1 wt% - 0.3 wt% of magnesium hydroxide and 0.2 wt% - 0.4 wt% of aluminum hydroxide; the antioxidant is composed of 0.1 wt% - 0.3 wt% of type 1010, 0.1 wt% - 0.3 wt% of type 168, and 0.05 wt% - 0.1 wt% of type 1024.

[0089] The preparation method of the above sandwich composite building formwork includes the following steps: Weigh each raw material of the surface layer and the core layer according to the mass fraction of the above raw materials.

[0090] Mix the broken particles of wind turbine blades, polypropylene, toughening agent, lubricant, flame retardant, antioxidant, ultraviolet absorber and second nucleating agent to obtain a mixture. Put the mixture into a mixer and heat it to 180 °C to plasticize it into a lump material, then extrude and granulate to obtain composite material particles. Put the composite material particles into a template production line to obtain a core layer with a thickness of 15 mm.

[0091] Mix the glass fibers recycled from wind turbine blades, lubricant, compatibilizer, first nucleating agent and polyethylene evenly, extrude and granulate, and hot press at 170 °C and 10 MPa for 15 min to obtain a surface layer with a thickness of 1 mm.

[0092] Stack them in the order of surface layer - core layer - surface layer, and hot press at 160 °C for the second time and control the thickness to be 17 mm to obtain a sandwich composite building template.

[0093] Comparative Example 2 Compared with Example 4, the difference is that the mass fraction of the glass fibers recycled from wind turbine blades is increased from 40% to 45%, and at the same time, the mass fraction of polyethylene with a density of 0.955 g / cm 3 is reduced from 50% to 45%.

[0094] A sandwich composite building template includes a surface layer and a core layer.

[0095] The surface layer is made of the following raw materials by mass fraction: 45% of the glass fibers recycled from wind turbine blades with a diameter of 17 μm and a length of 1 mm to 3 mm, 45% of polyethylene with a density of 0.955 g / cm 3 The melt flow rate of the polyethylene is 14 g / 10 min, the grade is CH1402, 6% of compatibilizer, 3.7% of the first lubricant pentaerythritol stearate and 0.3% of the first nucleating agent; the first nucleating agent is PE nucleating agent, and the grade is: HY - 9902.

[0096] The core layer is made of the following raw materials by mass fraction: 20% of the broken particles of wind turbine blades, 76% of polypropylene with a melt flow rate of 20 g / 10 min, the grade is BF970MO, 2% of toughening agent, 0.3% of the second lubricant, 0.5% of flame retardant, 0.4% of antioxidant, 0.5% of ultraviolet absorber UV329, 0.3% of the second nucleating agent.

[0097] The toughening agent is EVA of type 565; the second lubricant consists of 0.2wt% - 0.4wt% calcium stearate and 0.1wt% - 0.3wt% zinc stearate; the second nucleating agent is a PP nucleating agent with the brand number: JYN-611. The flame retardant consists of 0.1wt% - 0.3wt% magnesium hydroxide and 0.2wt% - 0.4wt% aluminum hydroxide; the antioxidant consists of 0.1wt% - 0.3wt% type 1010, 0.1wt% - 0.3wt% type 168 and 0.05wt% - 0.1wt% type 1024.

[0098] The preparation method of the above sandwich composite building formwork includes the following steps: Weigh each raw material of the surface layer and the core layer according to the mass fraction of the above raw materials.

[0099] Mix the broken particles of wind turbine blades, polypropylene, toughening agent, lubricant, flame retardant, antioxidant, ultraviolet absorber and the second nucleating agent to obtain a mixture. Put the mixture into a mixer and heat it to 180°C to plasticize it into a dough-like material, then extrude and granulate to obtain composite material particles. Put the composite material particles into the formwork production line to obtain a core layer with a thickness of 15 mm.

[0100] Mix the glass fiber recovered from wind turbine blades with lubricant, compatibilizer, the first nucleating agent and polyethylene evenly, extrude and granulate, and hot press it at 170°C and 10 MPa for 15 minutes to obtain a surface layer with a thickness of 1 mm.

[0101] Stack them in the order of surface layer - core layer - surface layer, and hot press them at 160°C for the second time and control the thickness to be 17 mm to obtain the sandwich composite building formwork.

[0102] Comparative Example 3 Compared with Example 1, the difference is that the mass fraction of the glass fiber recovered from wind turbine blades is decreased from 10% to 0%, and at the same time, the mass fraction of polyethylene with a density of 0.955 g / cm 3 is increased from 75% to 85%.

[0103] A sandwich composite building formwork, including a surface layer and a core layer.

[0104] The surface layer is made of the following raw materials by mass fraction: 0% of the glass fiber recovered from wind turbine blades, 85% of polyethylene with a density of 0.955 g / cm 3 The melt flow rate of the polyethylene is 14 g / 10 min, the brand number is CH1402, 11% of compatibilizer, 3.7% of the first lubricant pentaerythritol stearate and 0.3% of the first nucleating agent; the first nucleating agent is a PE nucleating agent with the brand number: HY-9902.

[0105] The core layer is made of raw materials with the following mass fractions: 20% of broken particles of wind turbine blades, 76% of polypropylene with a melt flow rate of 20 g / 10 min, 2% of toughening agent with the brand BF970MO, 0.3% of second lubricant, 0.5% of flame retardant, 0.4% of antioxidant, 0.5% of ultraviolet absorber UV329, and 0.3% of second nucleating agent.

[0106] The toughening agent is EVA of type 565; the second lubricant is composed of 0.2 wt% - 0.4 wt% of calcium stearate and 0.1 wt% - 0.3 wt% of zinc stearate; the second nucleating agent is a PP nucleating agent with the brand: JYN-611. The flame retardant is composed of 0.1 wt% - 0.3 wt% of magnesium hydroxide and 0.2 wt% - 0.4 wt% of aluminum hydroxide; the antioxidant is composed of 0.1 wt% - 0.3 wt% of type 1010, 0.1 wt% - 0.3 wt% of type 168, and 0.05 wt% - 0.1 wt% of type 1024.

[0107] The preparation method of the above sandwich composite building formwork includes the following steps: Weigh the raw materials of the surface layer and the core layer according to the mass fractions of the above raw materials.

[0108] Mix the broken particles of wind turbine blades, polypropylene, toughening agent, lubricant, flame retardant, antioxidant, ultraviolet absorber, and second nucleating agent to obtain a mixture. Put the mixture into a mixer and heat it to 180°C to plasticize it into a dough-like material, then extrude and pelletize to obtain composite material pellets. Put the composite material pellets into the formwork production line to obtain a core layer with a thickness of 15 mm.

[0109] Mix the glass fiber recovered from wind turbine blades with lubricant, compatibilizer, first nucleating agent, and polyethylene evenly, then extrude and pelletize. At 170°C and 10 MPa, hot press it for 15 min for the first time to obtain a surface layer with a thickness of 1 mm.

[0110] Stack them in the order of surface layer - core layer - surface layer, and hot press them for the second time at 160°C and control the thickness to be 17 mm to obtain the sandwich composite building formwork.

[0111] Detect the performance of the sandwich composite building formwork provided in the above Examples 1 - 6 and Comparative Examples 1 - 3 respectively. The results are shown in Table 1.

[0112] Table 1 Performance test table of the sandwich composite building formwork of the present invention in examples and comparative examples As can be seen from Table 1, the sandwich composite building formwork prepared by the present invention has excellent mechanical properties. The sandwich composite building formworks of Examples 1 to 6 of the present invention all have better flexural strength, flexural modulus of elasticity and impact strength. The flexural strength of the sandwich composite building formwork prepared by the present invention can reach 56.39 MPa, the flexural modulus of elasticity can reach 3193 MPa, and the impact strength can reach 15.95 kJ / m 2 . Comparative Example 1 to Comparative Example 3 are respectively improvements on the solutions based on the examples. In Comparative Example 1, on the basis of Example 1, the mass fraction of the glass fiber recovered from the wind turbine blade was decreased from 10% to 5%, and at the same time, the mass fraction of polyethylene with a density of 0.955 g / cm 3 was increased from 75% to 80%; Comparative Example 2 was based on Example 4, and the mass fraction of the glass fiber recovered from the wind turbine blade was increased from 40% to 45%, and at the same time, the mass fraction of polyethylene with a density of 0.955 g / cm 3 was decreased from 50% to 45%; the difference between Comparative Example 3 and Example 1 is that the mass fraction of the glass fiber recovered from the wind turbine blade was decreased from 10% to 0%, and at the same time, the mass fraction of polyethylene with a density of 0.955 g / cm 3 was increased from 75% to 85%. From the data in Table 1, it can be seen that the mechanical properties of the sandwich composite building formworks prepared in Comparative Example 1 to Comparative Example 3 are not good. The main reasons are as follows:

[0113] In Comparative Example 1, when the filling amount is 5 wt%, as a reinforcing phase, the glass fiber itself has relatively high strength and modulus, much higher than the polyethylene resin matrix. When the material is subjected to external force, the glass fiber can bear a large load, thus reducing the stress borne by the polyethylene matrix and improving the overall strength of the composite material. When the filling amount is too small, the reinforcing effect of the glass fiber cannot be fully exerted.

[0114] In Comparative Example 2, when the filling amount reaches 45 wt%, the performance is almost the same as that of the 40 wt% filling amount in Example 4. This is because when overfilled, the interaction between the glass fibers in the polyethylene resin may increase, resulting in a decrease in the mechanical properties of the polyethylene resin.

[0115] In Comparative Example 3, when the filling amount of the glass fiber is 0%, only polyethylene is used as the surface layer, and its flexural strength and impact strength are greatly reduced. The presence of the glass fiber will limit the movement of the polyethylene molecular chains. When stressed, the slippage and deformation of the polyethylene molecular chains are hindered by the glass fiber, reducing the deformation of the material and increasing the strength and stiffness.

[0116] In summary, in the present invention, glass fibers and carbon fibers contained in the broken particles of wind turbine blades are blended with polypropylene, greatly improving the mechanical properties of the core layer while effectively reducing costs. The surface layer is obtained by filling polyethylene with glass fibers recovered from wind turbine blades. The recovered glass fibers are doped into polyethylene, greatly improving the mechanical properties of the surface layer. Then, through hot pressing and composite molding, the polypropylene in the core layer is fused and attached to the polyethylene in the surface layer, thereby improving the interfacial bonding force between the surface layer and the core layer of the sandwich composite building formwork, and obtaining a sandwich composite building formwork with better mechanical properties.

[0117] Obviously, those skilled in the art can make various changes and deformations to the present invention without departing from the spirit and scope of the present invention. Thus, if these modifications and deformations of the present invention fall within the scope of the claims of the present invention and their equivalent technologies, the present invention also intends to include these modifications and deformations.

Claims

1. A sandwich composite building formwork, characterized in that, It includes a surface layer and a core layer, and the sandwich composite building formwork is stacked in the order of surface layer - core layer - surface layer; The surface layer is made of raw materials with the following mass fractions: 10% - 40% recycled glass fiber, 50% - 75% polyethylene, 6% - 11% compatibilizer, 2% - 4% first lubricant, and 0.1% - 0.3% first nucleating agent, totaling 100%; The core layer is made of raw materials with the following mass fractions: 20% - 40% crushed particles, 60% - 80% polypropylene, 1% - 3% toughening agent, 0.2% - 0.5% second lubricant, 0.2% - 0.7% flame retardant, 0.2% - 0.5% antioxidant, 0.2% - 0.5% ultraviolet absorber, and 0.3% - 1.2% second nucleating agent, totaling 100%; The crushed particles contain glass fiber and carbon fiber.

2. The sandwich composite building formwork according to claim 1, characterized in that, The diameter of the recycled glass fiber is 17μm, and the length is 1mm - 3mm.

3. The sandwich composite building formwork according to claim 1, characterized in that, The melt flow rate of the polypropylene is 20 g / 10 min; the melt flow rate of the polyethylene is 14 g / 10 min, and the density is 0.955 g / cm 3 .

4. The sandwich composite building formwork according to claim 1, characterized in that, The first lubricant is pentaerythritol stearate, and the second lubricant is composed of calcium stearate with a mass concentration of 0.2wt% - 0.4wt% and zinc stearate with a mass concentration of 0.1wt% - 0.3wt% in a mass ratio of 3:2; the first nucleating agent is a PE nucleating agent, and the second nucleating agent is a PP nucleating agent.

5. The sandwich composite building formwork according to claim 1, characterized in that, The toughening agent is EVA type 565, hydrogenated styrene - butadiene - styrene block copolymer, ethylene - propylene rubber, ethylene - octene copolymer, or ethylene - propylene - diene monomer rubber; the compatibilizer is maleic anhydride grafted polyethylene, and the ultraviolet absorber is UV329.

6. The sandwich composite building formwork according to claim 1, characterized in that, The flame retardant is composed of magnesium hydroxide with a mass concentration of 0.1wt% - 0.3wt% and aluminum hydroxide with a mass concentration of 0.2wt% - 0.4wt% in a mass ratio of 1:1; the antioxidant is composed of type 1010 with a mass concentration of 0.1wt% - 0.3wt%, type 168 with a mass concentration of 0.1wt% - 0.3wt%, and type 1024 with a mass concentration of 0.05wt% - 0.1wt% in a mass ratio of 1:2:

2.

7. A method for preparing the sandwich composite building formwork according to any one of claims 1 to 6, characterized in that, It includes the following steps: Weigh each raw material of the surface layer and the core layer according to the mass fractions in claim 1; Mix the crushed particles, polypropylene, toughening agent, lubricant, flame retardant, antioxidant, ultraviolet absorber, and second nucleating agent, heat the mixture to 175°C - 180°C to plasticize it into a dough - like material, extrude and pelletize to obtain composite material particles, and put the composite material particles into the formwork production line to obtain the core layer; Mix the recycled glass fiber evenly with the lubricant, compatibilizer, first nucleating agent, and polyethylene, extrude and pelletize, and perform a one - time hot pressing at 165°C - 175°C to obtain the surface layer; Stack them in the order of surface layer - core layer - surface layer, perform a secondary hot pressing at 130°C - 190°C and control the thickness to obtain the sandwich composite building formwork.

8. The preparation method of the sandwich composite building formwork according to claim 1, characterized in that, The thickness of the core layer is 15mm - 18mm, and the thickness of the surface layer is 0.5mm - 1mm.

9. The preparation method of the sandwich composite building formwork according to claim 1, characterized in that, The thickness control is controlled by a thickness control module. During the secondary hot pressing, the thickness in the heating section is 16.5mm - 20.5mm, and the thickness in the cooling section is 15.5mm - 19.5mm.

10. The preparation method of the sandwich composite building formwork according to claim 1, characterized in that, The pressure for the first hot pressing is 10 MPa and the time is 15 min.

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