Environment-friendly template material for building and preparation method of environment-friendly template material

Abstract

The invention belongs to the technical field of composite materials, and particularly relates to an environment-friendly template material for buildings and a preparation method of the environment-friendly template material. The composite material mainly comprises the following components in parts by weight: 55-65 parts of high-viscosity polypropylene, 10-20 parts of low-viscosity polypropylene, 8-14 parts of carbon fibers, 3-6 parts of hollow glass microspheres and 2-5 parts of nano silicon dioxide. The particle size of the nano silicon dioxide is 100 to 500 nm. The carbon fibers, the nano silicon dioxide and the hollow glass microspheres are introduced into the polypropylene-based composite material at the same time, the good reinforcing and toughening effects of the carbon fibers and the effective filling effect of the nano silicon dioxide and the hollow glass microspheres are played at the same time, and the composite material has the advantages of few gaps, high density, high tensile strength, good toughness and high bearing strength; the application prospect is wide.

Description

Technical Field

[0001] The present invention belongs to the technical field of composite materials, and particularly relates to an environment-friendly formwork material for construction and a preparation method thereof. Background Art

[0002] Construction formworks mainly include plywood formworks, metal formworks and plastic formworks. Plywood formworks mainly include wood plywood and bamboo plywood. Such formworks have large format, are relatively flexible in on-site processing, can meet the concrete pouring of various planar forms, and have the advantage of high strength-to-weight ratio. They are one of the most widely used forms in formwork projects at home and abroad. However, the plywood formworks have limited recycling times, too few recycling times, and low recycling rate, causing great waste of wood resources and being unsuitable for the current situation of scarce forest resources in China.

[0003] Metal formworks include steel formworks and aluminum alloy formworks. The production process of steel formworks is cumbersome, and the production of steel causes certain pollution to the surrounding environment. Therefore, the use of steel formworks is restricted. Compared with steel formworks, aluminum alloy formworks are lighter in self-weight, can be manually carried, reducing the use of tower cranes during construction; and have more turnover times and lower average cost; but aluminum alloy formworks require higher technical levels of installation personnel and have a large upfront investment, and can only show advantages in large-scale group projects or super-high-rise projects; they are not yet suitable for non-standard floors such as basements and transfer floors and corrosive places such as high-salt areas. Therefore, aluminum alloy formworks are still some distance from wide use. With the development of society, the construction industry will inevitably put forward higher and more comprehensive requirements for formwork materials. In the case of the decreasing availability of natural resources, how to use low-quality raw materials to prepare high-performance materials by means of compounding and combination will be one of the important development directions of the composite material industry in the future. In recent years, the research and utilization of resin composite materials for construction formworks have begun to receive attention.

[0004] Resin has many excellent properties, such as small density, great plasticity and ductility, good electrical insulation, etc., enabling it to be widely used in various fields and being closely related to people's lives. Resin materials are more corrosion-resistant than metal materials and can be applied to various corrosive construction sites. Among them, non-polar polyethylene, polypropylene and low-polar polyvinyl chloride, etc., make the surface of the composite material inert and not easily adhere to concrete, and are expected to be widely used in the construction formwork industry, which is of great significance for alleviating the problems of scarce forest resources and environmental pollution caused by waste plastics in China.

[0005] Polypropylene is a general-purpose thermoplastic obtained by polymerization of propylene. The solid polypropylene is colorless and translucent, non-toxic and odorless. Its molecular structure is relatively regular, easy to crystallize, and has a high degree of crystallization, resulting in a high melting point of polypropylene (about 167°C). However, compared with polar resins such as polyamide, polypropylene has low mechanical strength and poor impact resistance, which limits its application in the field of building formwork. The existing technology improves the performance of polypropylene composite materials by adding inorganic reinforcing fillers. Although the mechanical strength of polypropylene composite materials is improved to a certain extent, it is usually accompanied by a decrease in impact toughness. Therefore, how to further improve the toughness of polypropylene on the basis of improving its mechanical strength has become an urgent problem to be solved in polypropylene composite materials for building formwork. Summary of the invention

[0006] In order to solve the technical problem that the strength and toughness of the existing polypropylene materials mentioned in the above background technology are difficult to balance, the present invention provides an environmentally friendly building formwork material, which comprises the following components in parts by weight: 55-65 parts of high viscosity polypropylene, 10-20 parts of low viscosity polypropylene, 8-14 parts of carbon fiber, 3-6 parts of hollow glass microspheres, 2-5 parts of nano silicon dioxide; the nano silicon dioxide particle size is 100-500nm. The nano silicon dioxide particle size can be any value between 100-500nm, specifically 100nm, 150nm, 200nm, 250nm, 300nm, 350nm, 400nm, 450nm, 500nm, etc. In particular, the nano silicon dioxide particle size is 200-300nm; the appropriate particle size can enhance and promote the volume matching between fillers.

[0007] The invention achieves the required performance by compounding polypropylene resins with different viscosities under a specific composite reinforcing filler addition ratio: when a low-viscosity polypropylene resin is used alone or in a high amount, the impact resistance of the polypropylene material decreases, the toughness is insufficient, and the inorganic filler cannot be tightly connected due to insufficient viscosity, resulting in reduced uniformity inside the composite material and easily causing stress concentration; when a high-viscosity polypropylene resin is used alone or in a high amount, the polypropylene material has insufficient fluidity during processing and the filler is unevenly dispersed, which also affects the mechanical properties of the polypropylene composite material.

[0008] Meanwhile, the composite reinforcing filler of the present invention is composed of nano-scale silica, hollow glass microspheres and carbon fibers. The nano-scale silica is a nano-scale filler, while the glass microspheres and carbon fibers are both common micron-scale fillers in the art.

[0009] Among them, the diameter of carbon fiber is generally about 5-10μm, while the diameter of hollow glass microspheres is usually between 30-100μm. Among the above inorganic fillers, carbon fibers with medium diameter play a role in skeleton reinforcement and load transfer, while the polypropylene resin matrix plays a role in connecting the fibers, which can transfer and disperse the stress received, bear the tensile and compressive loads perpendicular to the fibers, and protect the fibers from damage. The volume average particle size D50 of nano-silica is 100-500nm. If the diameter is too large, it cannot play the role of rigid particle reinforcement; if the diameter is too small, not only may there be problems with difficult dispersion, but also it cannot form a volume matching effect with large-diameter hollow glass microspheres and medium-diameter carbon fibers, and cannot form a uniform dense structure, and cannot effectively absorb impact energy, which is not conducive to improving toughness.

[0010] The reason for choosing carbon fiber in the present invention is that compared with high-rigidity fibers such as glass fiber, carbon fiber has good flexibility, and it is easier to undergo elastic deformation during the blending process with glass microspheres and nano-silica, promoting the uniformity of filler dispersion.

[0011] The present invention simultaneously introduces carbon fiber, small-particle-size silica, and large-particle-size hollow glass microspheres into the polypropylene-based composite material, simultaneously exerting the good strengthening and toughening effects of carbon fiber and the effective filling effects of small-particle-size silica and large-particle-size hollow glass microspheres. The prepared multi-scale carbon fiber polypropylene composite material has excellent performance. The fibers, small-particle-size silica, large-particle-size hollow glass microspheres and the polypropylene matrix are tightly combined. There are few voids in the composite material, and the density is high. It has the advantages of large tensile strength, good toughness, and high bearing strength. Carbon fiber, small-particle-size silica, and large-particle-size hollow glass microspheres form a multi-scale composite reinforcement skeleton. Among them, the large-particle-size hollow glass microspheres are dispersed in the skeleton network formed by the resin matrix and carbon fiber. The spherical structure helps to disperse the residual stress on the carbon fiber; the small-particle-size silica fills the voids formed between the glass microspheres and the carbon fiber, forming a ball bearing effect, further dispersing the stress on the matrix, and at the same time improving the uniformity of the density of the composite material and preventing stress concentration. Generally speaking, the stress transfer between the fibers, small-particle-size silica, and large-particle-size hollow glass microspheres is beneficial to dispersing the stress concentration points, so as to achieve the purpose of synergistic strengthening and toughening, and improve the toughness and strength of the composite material.

[0012] Particularly, under the conditions of 230°C / 2.16kg, the melt index of the high-viscosity polypropylene is 5-10g / 10min. Specifically, it can be 5g / 10min, 6g / 10min, 7g / 10min, 8g / 10min, 9g / 10min, 10g / 10min, etc.

[0013] Specifically, the low-viscosity polypropylene has a melt index of 20 - 50 g / 10 min under the conditions of 230 °C / 2.16 kg. Specifically, it can be 20 g / 10 min, 25 g / 10 min, 30 g / 10 min, 35 g / 10 min, 40 g / 10 min, 45 g / 10 min, 50 g / 10 min, etc.

[0014] By compounding polypropylene resins with different viscosities, the bonding and dispersion properties of the filler can be balanced, and the mechanical strength of the composite material can be improved. Further, 57 - 62 parts of high-viscosity polypropylene and 13 - 16 parts of low-viscosity polypropylene. An appropriate amount of low-viscosity polypropylene can balance the roles of dispersion and reinforcement. When the dosage is too small, the melt fluidity is likely to decrease and the processing performance is affected; when the dosage is too large, due to the low density of the hollow microspheres and their "floating" characteristics, uneven dispersion of the hollow-structured microspheres may occur, affecting the mechanical properties of the product.

[0015] Specifically, the carbon fiber is short-cut carbon fiber with a diameter of 5 - 10 μm. There is no particular limitation on the type of carbon fiber, and types such as polyacrylonitrile-based carbon fiber, pitch-based carbon fiber, or rayon-based carbon fiber can all be used. The present invention utilizes the volume matching effect between fillers to improve the dispersion performance of inorganic materials in polypropylene, without the need for complex modification of the carbon fiber, and the process is simpler.

[0016] Specifically, the particle size of the hollow glass microspheres is 30 - 100 μm. Specifically, it can be 30 μm, 40 μm, 50 μm, 60 μm, 70 μm, 80 μm, 90 μm, 100 μm, etc. There is no particular limitation on the wall thickness of the hollow glass microspheres, which is generally between 0.5 - 2 μm. The interior of the hollow glass microspheres is hollow. When applied to the construction industry, it will not only not increase the extra burden on the building structure, but also reduce the possibility of leakage due to excessive structural load. The addition of hollow microspheres will not only reduce the density of the matrix, but also improve the stiffness, strength, and dimensional stability of the matrix. Since the hollow glass microspheres are small spheres, they have better fluidity in the resin than linear carbon fiber fillers, so the mold filling performance is excellent. More importantly, these small microspheres are isotropic, so there will be no problem of inconsistent shrinkage rates in different parts due to orientation, ensuring the dimensional stability of the product and no warping.

[0017] Specifically, the environmentally friendly formwork material for construction also contains additives.

[0018] Specifically, the additive is at least one of an interfacial compatibilizer, a coupling agent, a lubricant, an antioxidant, a flow modifier, and a colorant.

[0019] Specifically, the interfacial compatibilizer is selected from at least one of maleic anhydride grafted polyethylene, maleic anhydride grafted polypropylene, and maleic anhydride grafted ethylene-octene copolymer.

[0020] Specifically, the coupling agent is selected from at least one of titanate coupling agents, silane coupling agents, and aluminate coupling agents; the lubricant is selected from at least one of zinc stearate, paraffin wax, ethylene bisstearamide, modified ethylene bisstearamide, silicone powder, polyethylene wax, polysiloxane, amide wax, oleic acid amide, and erucic acid amide; the antioxidant is selected from at least one of hindered phenol antioxidants and phosphite antioxidants. There are no specific limitations on the types of flow modifiers and colorants, and common types in the art can be used.

[0021] On the other hand, the present invention also provides a preparation method of an environment-friendly formwork material for construction, comprising the following steps: Weigh each component according to the ratio, and add high-viscosity polypropylene, low-viscosity polypropylene, hollow glass microspheres, and nano-silica into a twin-screw extruder through the main feeding port; add carbon fiber into the twin-screw extruder through the side feeding port, and melt and extrude to granulate, thus obtaining the environment-friendly formwork material for construction. Among them, the process parameters of the extruder are not particularly limited, the extrusion temperature can be controlled between 170 - 220 °C, and the screw speed can be controlled between 100 - 600 r / min.

[0022] Beneficial effects: Compared with the existing technology, the environment-friendly formwork material for construction provided by the present invention has an inert surface for the composite material, is not easily adhered to concrete, can greatly meet the performance requirements of the main material for concrete pouring, has high strength and high toughness for the resin composite material, and has excellent comprehensive performance, and can be widely used in the field of construction formwork. Specific embodiments

[0023] The technical solution of the present invention will be further described below through specific embodiments. Those skilled in the art should understand that the embodiments are only for helping to understand the present invention and should not be regarded as specific limitations on the present invention.

[0024] Unless otherwise specified, the types of materials used in the present invention are all the same, and can all be obtained through commercial purchase or prepared by conventional methods.

[0025] Specifically, the types of raw material components in the examples and comparative examples are the same, and the specific components are as follows: The high-viscosity polypropylene has a melt index of 8 g / 10 min under the conditions of 230 °C / 2.16 kg; the low-viscosity polypropylene has a melt index of 30 g / 10 min under the conditions of 230 °C / 2.16 kg; the carbon fiber is short-cut carbon fiber with a length of 6 mm and a diameter of 8 μm; the hollow glass microspheres have a particle size of 50 μm and a wall thickness of 1 μm.

[0026] The preparation methods of the following examples and comparative examples are the same, and specifically include the following steps: Weigh each component according to the ratio, and add high-viscosity polypropylene, low-viscosity polypropylene, hollow glass microspheres, nano-silica, and additives into the twin-screw extruder through the main feeding port; add carbon fiber into the twin-screw extruder through the side feeding port, and melt and extrude to granulate, thus obtaining the environmentally friendly formwork material for construction; the extrusion temperature is 200 °C, and the screw speed is 200 r / min.

[0027] Example 1 An environmentally friendly formwork material for construction, in parts by weight, comprises the following components: 55 parts of high-viscosity polypropylene, 13 parts of low-viscosity polypropylene, 8 parts of carbon fiber, 3 parts of hollow glass microspheres, 2 parts of nano-silica, 1 part of interfacial compatibilizer, 1 part of coupling agent, 0.2 part of lubricant, 0.5 part of antioxidant 1010; the volume average particle size of the nano-silica is 100 nm; the interfacial compatibilizer is maleic anhydride grafted polyethylene; the coupling agent is KH550; the lubricant is zinc stearate.

[0028] Example 2 An environmentally friendly formwork material for construction, in parts by weight, comprises the following components: 65 parts of high-viscosity polypropylene, 16 parts of low-viscosity polypropylene, 14 parts of carbon fiber, 6 parts of hollow glass microspheres, 5 parts of nano-silica, 3 parts of interfacial compatibilizer, 2 parts of coupling agent, 1 part of lubricant, 1 part of antioxidant 1010; the volume average particle size of the nano-silica is 300 nm; the interfacial compatibilizer is maleic anhydride grafted polypropylene; the coupling agent is KH560; the lubricant is paraffin.

[0029] Example 3 An environmentally friendly formwork material for construction, in parts by weight, comprises the following components: 58 parts of high-viscosity polypropylene, 10 parts of low-viscosity polypropylene, 12.5 parts of carbon fiber, 4.5 parts of hollow glass microspheres, 3.5 parts of nano-silica, 1.2 parts of interfacial compatibilizer, 1.4 parts of coupling agent, 1 part of lubricant, 0.7 part of antioxidant 1010; the volume average particle size of the nano-silica is 200 nm; the interfacial compatibilizer is maleic anhydride grafted polyethylene; the coupling agent is KH570; the lubricant is ethylene bis-stearamide.

[0030] Example 4 An environmentally friendly formwork material for construction, in parts by weight, comprises the following components: 55 parts of high-viscosity polypropylene, 16 parts of low-viscosity polypropylene, 8 parts of carbon fiber, 6 parts of hollow glass microspheres, 2 parts of nano-silica, 3 parts of interfacial compatibilizer, 1 part of coupling agent, 1 part of lubricant, 0.5 part of antioxidant 1010; the volume average particle size of the nano-silica is 300 nm; the interfacial compatibilizer is maleic anhydride grafted ethylene-octene copolymer; the coupling agent is KH570; the lubricant is polyethylene wax.

[0031] Example 5 An environmentally friendly formwork material for construction, in parts by weight, comprises the following components: 60 parts of high-viscosity polypropylene, 20 parts of low-viscosity polypropylene, 12 parts of carbon fiber, 5 parts of hollow glass microspheres, 4 parts of nano-silica, 2.1 parts of interfacial compatibilizer, 1.6 parts of coupling agent, 0.7 part of lubricant, 0.8 part of antioxidant 1010; the volume average particle size of the nano-silica is 200 nm; the interfacial compatibilizer is maleic anhydride grafted polypropylene; the coupling agent is KH550; the lubricant is zinc stearate.

[0032] Example 6 An environmentally friendly formwork material for construction, in parts by weight, comprises the following components: 57 parts of high-viscosity polypropylene, 14 parts of low-viscosity polypropylene, 10 parts of carbon fiber, 4 parts of hollow glass microspheres, 3 parts of nano-silica, 1.5 parts of interfacial compatibilizer, 1.3 parts of coupling agent, 0.6 part of lubricant, 0.6 part of antioxidant 1010; the volume average particle size of the nano-silica is 100 nm; the interfacial compatibilizer is maleic anhydride grafted polyethylene; the coupling agent is KH550; the lubricant is ethylene bis-stearamide.

[0033] Example 7 An environmentally friendly formwork material for construction, in parts by weight, comprises the following components: 60 parts of high-viscosity polypropylene, 14 parts of low-viscosity polypropylene, 12 parts of carbon fiber, 5 parts of hollow glass microspheres, 4 parts of nano-silica, 2.1 parts of interfacial compatibilizer, 1.6 parts of coupling agent, 0.7 part of lubricant, 0.8 part of antioxidant 1010; the volume average particle size of the nano-silica is 500 nm; the interfacial compatibilizer is maleic anhydride grafted polypropylene; the coupling agent is KH550; the lubricant is zinc stearate.

[0034] Example 8 An environmentally friendly formwork material for construction, in parts by weight, comprises the following components: 62 parts of high-viscosity polypropylene, 15 parts of low-viscosity polypropylene, 13 parts of carbon fiber, 5 parts of hollow glass microspheres, 4 parts of nano-silica, 2.5 parts of interfacial compatibilizer, 1.8 parts of coupling agent, 0.8 part of lubricant, 0.9 part of antioxidant 1010; the volume average particle size of the nano-silica is 300 nm; the interfacial compatibilizer is maleic anhydride grafted polyethylene; the coupling agent is KH560; the lubricant is zinc stearate.

[0035] Example 9 An environmentally friendly formwork material for construction, by weight, comprises the following components: 59 parts of high-viscosity polypropylene, 15 parts of low-viscosity polypropylene, 11 parts of carbon fiber, 4.5 parts of hollow glass microspheres, 3.5 parts of nano-silica, 1.8 parts of interfacial compatibilizer, 1.3 parts of coupling agent, 0.5 part of lubricant, 0.8 part of antioxidant 1010; the volume average particle size of the nano-silica is 100 nm; the interfacial compatibilizer is maleic anhydride grafted polypropylene; the coupling agent is KH570; the lubricant is paraffin wax.

[0036] Example 10 An environmentally friendly formwork material for construction, by weight, comprises the following components: 64 parts of high-viscosity polypropylene, 15 parts of low-viscosity polypropylene, 10 parts of carbon fiber, 5.5 parts of hollow glass microspheres, 4.5 parts of nano-silica, 2.2 parts of interfacial compatibilizer, 1.2 parts of coupling agent, 0.6 part of lubricant, 0.8 part of antioxidant 1010; the volume average particle size of the nano-silica is 300 nm; the interfacial compatibilizer is maleic anhydride grafted ethylene-octene copolymer; the coupling agent is KH550; the lubricant is polyethylene wax.

[0037] Example 11 An environmentally friendly formwork material for construction, by weight, comprises the following components: 60 parts of high-viscosity polypropylene, 14 parts of low-viscosity polypropylene, 12 parts of carbon fiber, 5 parts of hollow glass microspheres, 4 parts of nano-silica, 2.1 parts of interfacial compatibilizer, 1.6 parts of coupling agent, 0.7 part of lubricant, 0.8 part of antioxidant 1010; the volume average particle size of the nano-silica is 200 nm; the interfacial compatibilizer is maleic anhydride grafted polypropylene; the coupling agent is KH550; the lubricant is zinc stearate.

[0038] Comparative Example 1 An environmentally friendly formwork material for construction, by weight, comprises the following components: 60 parts of high-viscosity polypropylene, 14 parts of low-viscosity polypropylene, 12 parts of carbon fiber, 0 parts of hollow glass microspheres, 9 parts of nano-silica, 2.1 parts of interfacial compatibilizer, 1.6 parts of coupling agent, 0.7 parts of lubricant, 0.8 parts of antioxidant 1010; the volume average particle size of the nano-silica is 200 nm; the interfacial compatibilizer is maleic anhydride grafted polypropylene; the coupling agent is KH550; the lubricant is zinc stearate.

[0039] Comparative Example 2 An environmentally friendly formwork material for construction, in parts by weight, comprises the following components: 60 parts of high-viscosity polypropylene, 14 parts of low-viscosity polypropylene, 12 parts of carbon fiber, 9 parts of hollow glass microspheres, 0 parts of nano-silica, 2.1 parts of interfacial compatibilizer, 1.6 parts of coupling agent, 0.7 parts of lubricant, 0.8 parts of antioxidant 1010; the volume average particle size of the nano-silica is 200 nm; the interfacial compatibilizer is maleic anhydride grafted polypropylene; the coupling agent is KH550; the lubricant is zinc stearate.

[0040] Comparative Example 3 An environmentally friendly formwork material for construction, in parts by weight, comprises the following components: 60 parts of high-viscosity polypropylene, 14 parts of low-viscosity polypropylene, 12 parts of carbon fiber, 5 parts of hollow glass microspheres, 4 parts of nano-silica, 2.1 parts of interfacial compatibilizer, 1.6 parts of coupling agent, 0.7 parts of lubricant, 0.8 parts of antioxidant 1010; the volume average particle size of the nano-silica is 50 nm; the interfacial compatibilizer is maleic anhydride grafted polypropylene; the coupling agent is KH550; the lubricant is zinc stearate.

[0041] Comparative Example 4 An environmentally friendly formwork material for construction, in parts by weight, comprises the following components: 60 parts of high-viscosity polypropylene, 14 parts of low-viscosity polypropylene, 12 parts of carbon fiber, 5 parts of hollow glass microspheres, 8 parts of nano-silica, 2.1 parts of interfacial compatibilizer, 1.6 parts of coupling agent, 0.7 parts of lubricant, 0.8 parts of antioxidant 1010; the volume average particle size of the nano-silica is 200 nm; the interfacial compatibilizer is maleic anhydride grafted polypropylene; the coupling agent is KH550; the lubricant is zinc stearate.

[0042] Performance testing: The materials prepared in Examples 1 - 11 and Comparative Examples 1 - 4 were injection molded into standard specimens, and under the same test conditions, their mechanical properties such as tensile strength (specifically referring to ASTM D638), flexural strength MPa (specifically referring to ASTM D790), and notched impact strength (specifically referring to ISO179) were tested respectively. The test results are shown in Tables 1 - 2 below.

[0043] Table 1 Table 2 It can be seen from the data in Table 1 and Table 2 that when carbon fiber, nano-silica, and hollow glass microspheres with a specific ratio are simultaneously introduced into the polypropylene-based composite material, the good strengthening and toughening effects of carbon fiber and the effective filling effects of nano-silica with small particle size and glass microspheres with large particle size are simultaneously exerted. Stress transfer occurs among the three, which is beneficial to dispersing stress concentration points, thereby achieving the purpose of synergistic strengthening and toughening.

[0044] Compared with Example 11, Comparative Examples 1-2 lack nano-silica or hollow glass microspheres respectively, and cannot effectively form a multi-scale composite reinforcement framework. The uniformity of the composite material becomes worse, and the impact toughness and mechanical strength decrease. It can be seen from Comparative Example 3 that when the particle size of nano-silica is too small, not only may there be problems with its own dispersion difficulties, but also it cannot form a volume matching effect with large-particle-size hollow glass microspheres and medium-diameter carbon fibers, and cannot form a uniform dense structure, and cannot effectively absorb impact energy. Although the tensile strength and flexural strength change little, the impact toughness decreases significantly. It can be seen from Comparative Example 4 that when the amount of nano-silica is too much, due to difficult dispersion, excessive filling occurs, the tensile strength only changes slightly, and the impact strength decreases significantly, which is not conducive to the improvement of mechanical properties.

[0045] The above description of the embodiments is for the convenience of those of ordinary skill in the art in this technical field to understand and apply the present invention. Those who are familiar with the technology in this field can obviously easily make various modifications to the embodiments and apply the general principles of this description to other embodiments without creative labor. Therefore, the present invention is not limited to the embodiments here, and the improvements and modifications made by those skilled in the art without departing from the scope of the present invention according to the disclosure of the present invention should be within the protection scope of the present invention.

Claims

1. An environmentally friendly formwork material for construction, characterized in that, By weight parts, it comprises the following components: 55 - 65 parts of high-viscosity polypropylene, 10 - 20 parts of low-viscosity polypropylene, 8 - 14 parts of carbon fiber, 3 - 6 parts of hollow glass microspheres, 2 - 5 parts of nano-silica; the particle size of the nano-silica is 100 - 500 nm.

2. The environmentally friendly formwork material for construction according to claim 1, characterized in that, The high-viscosity polypropylene has a melt index of 5 - 10 g / 10 min under the conditions of 230 °C / 2.16 kg.

3. The environmentally friendly formwork material for construction according to claim 1, wherein The low-viscosity polypropylene has a melt index of 20 - 50 g / 10 min under the conditions of 230 °C / 2.16 kg.

4. The environmentally friendly formwork material for construction according to claim 1, characterized in that, The carbon fiber is short-cut carbon fiber with a diameter of 5 - 10 μm.

5. An environmentally friendly formwork material for construction according to claim 1, characterized in that, The particle size of the hollow glass microspheres is 30 - 100 μm.

6. The environmentally friendly formwork material for construction according to claim 1, characterized in that, The environmentally friendly formwork material for construction further comprises an additive.

7. An environmentally friendly formwork material for construction according to claim 6, characterized in that, The additive is at least one of an interfacial compatibilizer, a coupling agent, a lubricant, an antioxidant, a flow modifier, and a colorant.

8. An environmentally friendly formwork material for construction according to claim 7, characterized in that, The interfacial compatibilizer is selected from at least one of maleic anhydride grafted polyethylene, maleic anhydride grafted polypropylene, and maleic anhydride grafted ethylene-octene copolymer.

9. An environmentally friendly formwork material for construction as claimed in claim 7, wherein The coupling agent is selected from at least one of titanate coupling agent, silane coupling agent, and aluminate coupling agent; the lubricant is selected from at least one of zinc stearate, paraffin wax, ethylene bis-stearamide, modified ethylene bis-stearamide, silicone powder, polyethylene wax, polysiloxane, amide wax, oleic acid amide, and erucic acid amide; the antioxidant is selected from at least one of hindered phenol antioxidants and phosphite antioxidants.

10. The preparation method of an environmentally friendly formwork material for construction according to claim 1, characterized in that, It includes the following steps: Weigh each component according to the ratio, add the high-viscosity polypropylene, low-viscosity polypropylene, hollow glass microspheres, and nano-silica into the twin-screw extruder through the main feeding port; add the carbon fiber into the twin-screw extruder through the side feeding port, and melt and extrude to granulate, thus obtaining the environmentally friendly formwork material for construction.

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