Weather-resistant polymer composite tarpaulin with gradient density structure and forming process of weather-resistant polymer composite tarpaulin

Abstract

The invention relates to the technical field of composite tarpaulin production, in particular to weather-resistant polymer composite tarpaulin with a gradient density structure and a forming process of the weather-resistant polymer composite tarpaulin. The material comprises the following raw materials: styrene-butadiene rubber, thermoplastic polyolefin, a compatibilizer and an additive, the compatibilizer adopts maleic anhydride grafted thermoplastic polyolefin; the comprehensive performance of the tarpaulin is improved through the ratio of the raw materials and the preparation process, the binding force and compatibility between the styrene-butadiene rubber and the thermoplastic polyolefin are enhanced through the compatibilizer, a mixed system is more uniform and stable, oxidation of a high polymer material is effectively delayed through the antioxidant, and the service life of the tarpaulin is prolonged. The ultraviolet light absorber is used for preventing tarpaulin aging; and in the forming process, the materials can be more fully and uniformly mixed to form a stable gradient density structure, so that the overall density and uniformity of the tarpaulin are effectively improved, and the structural integrity and stability are improved, thereby enhancing the weather resistance and protection property of the tarpaulin and prolonging the service life of the tarpaulin.

Description

Technical Field

[0001] The present invention relates to the technical field of composite tarpaulin production, and specifically, to a weather-resistant polymer composite tarpaulin with a gradient density structure and its forming process. Background Art

[0002] In modern industry and daily life, as an important covering and protective material, tarpaulins are widely used in many fields such as construction, goods transportation, and warehousing. With the change of the global environment, the increase in extreme weather, and the increasingly harsh outdoor environmental conditions, extremely high requirements are put forward for the comprehensive performance of tarpaulins, such as weather resistance, strength, and flexibility.

[0003] Traditional tarpaulin materials have frequent problems in complex outdoor environments. After long-term exposure to ultraviolet radiation, frequent temperature fluctuations, and wind and rain attacks, they are extremely prone to aging, embrittlement, and even damage, greatly shortening their service life. Thermoplastic polyolefin (TPO), as a high-quality thermoplastic plastic, combines the advantages of rubber and plastic, has good weather resistance, chemical corrosion resistance, high elasticity, and excellent processing performance. However, a tarpaulin made of a single thermoplastic polyolefin (TPO) material has limited structural stability and anti-deformation ability when facing mechanical stress in extreme environments, such as in strong winds, heavy snow, and other harsh weather conditions, which is likely to affect the integrity and protective function of the tarpaulin. Moreover, during the long-term outdoor use of TPO tarpaulins, scratches and abrasions are likely to occur on their surfaces, resulting in a decline in their weather resistance and affecting their service life.

[0004] In addition, for some tarpaulins with a multi-layer structure, for example, Chinese Patent Publication No. CN114670524A discloses a composite tarpaulin with high peel strength and its production method. Both the woven mesh cloth and the TPU film are coated with PUR glue layers, and the two PUR glue layers can be perfectly melt-bonded together during bonding, making the entire composite tarpaulin have high peel strength performance and not being easily torn apart. However, the bonding parts between the layers of the tarpaulin are prone to becoming stress concentration points, and when subjected to external force impacts, they are likely to start to be damaged from the bonding parts, affecting the overall service life of the tarpaulin. At the same time, due to the differences in physical properties such as density and hardness between the materials of each layer of this multi-layer structure tarpaulin, the overall weight distribution is uneven, which will increase the difficulty of installation and fixation during use. Moreover, the wear degrees of different layer materials are inconsistent, and the softer or thinner layers are prone to wear first, resulting in a decline in the overall protective performance of the tarpaulin, thereby reducing the overall performance and service life of the tarpaulin. Summary of the Invention

[0005] The purpose of the present invention is to provide a weather-resistant polymer composite tarpaulin with a gradient density structure and its forming process to solve the problems raised in the above background art.

[0006] To achieve the above object, on the one hand, the present invention provides a forming process for a weather-resistant polymer composite tarpaulin with a gradient density structure, comprising the following steps:

[0007] S1. Raw material preparation: styrene-butadiene rubber, thermoplastic polyolefin, compatibilizer and additives, wherein the compatibilizer is used to enhance the bonding force and compatibility between the styrene-butadiene rubber and the thermoplastic polyolefin;

[0008] S2. Blending: Add the styrene-butadiene rubber, thermoplastic polyolefin, compatibilizer and additives into a high-speed mixer for preliminary mixing, and then transfer them into a twin-screw extruder for mixing and melting to obtain a material. At this time, the compatibilizer can undergo a nucleophilic addition reaction with the styrene-butadiene rubber to form chemical bonds for stabilizing the generation of the gradient density structure;

[0009] S3. Gradient density structure construction: Use a mold with a gradient structure, and extrude the uniformly mixed material into the interior of the mold at a speed of 5 kg / h - 9 kg / h and a pressure of 13 MPa - 17 MPa through a twin-screw extruder;

[0010] S4. Forming: After the material forms a stable gradient density structure, use a flat extrusion method or a blow molding extrusion method for extrusion to obtain a tarpaulin;

[0011] S5. Post-treatment: Place the formed tarpaulin in a heat treatment device for treatment, and then take it out and cool it naturally to obtain the finished tarpaulin.

[0012] As a further improvement of this technical solution, in S1, the compatibilizer adopts maleic anhydride grafted thermoplastic polyolefin.

[0013] As a further improvement of this technical solution, in S2, the preliminary mixing speed of the high-speed mixer is 800 r / min - 120 r / min, and the preliminary mixing time of the high-speed mixer is 6 min - 10 min.

[0014] As a further improvement of this technical solution, in S2, the twin-screw extruder adopts a parallel co-rotating twin-screw extruder, the temperature of the twin-screw extruder is controlled at 190°C - 220°C, the screw speed is 210 r / min - 240 r / min, and the material is fully mixed and melted in the extruder for 15 min - 20 min.

[0015] As a further improvement of this technical solution, in S3, the mold with a gradient structure can adopt a multi-layer co-extrusion mold, the number of flow channels of the mold is 5 - 8 layers, the temperature at the inlet of the mold is 220°C - 230°C, and the temperature at the outlet of the mold is 180°C - 190°C.

[0016] As a further improvement of this technical solution, in S5, the heat treatment temperature of the heat treatment equipment is 105°C - 115°C, and the heat treatment time of the heat treatment equipment is 40 min - 50 min.

[0017] On the other hand, the present invention provides a weather-resistant polymer composite tarpaulin with a gradient density structure, comprising the following raw materials:

[0018] The dosage of styrene-butadiene rubber accounts for 24% - 30% of the total mass;

[0019] The dosage of thermoplastic polyolefin accounts for 50% - 60% of the total mass;

[0020] The dosage of compatibilizer accounts for 7% - 12% of the total mass;

[0021] The dosage of additive accounts for 5% - 10% of the total mass.

[0022] As a further improvement of this technical solution, the additive includes an antioxidant, an ultraviolet absorber, and a filler, wherein:

[0023] The dosage of the antioxidant accounts for 0.8% - 1.8% of the total mass;

[0024] The dosage of the ultraviolet absorber accounts for 0.8% - 1.8% of the total mass;

[0025] The dosage of the filler accounts for 4% - 7% of the total mass.

[0026] As a further improvement of this technical solution, the antioxidant is a hindered phenol antioxidant; the ultraviolet absorber is a benzophenone ultraviolet absorber; the filler includes at least calcium carbonate and talc powder.

[0027] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0028] 1. In the weather-resistant polymer composite tarpaulin with a gradient density structure and its preparation method, through the raw material ratio and preparation process, the comprehensive performance of the tarpaulin is improved. Not only does the compatibilizer enhance the bonding force and compatibility between styrene-butadiene rubber and thermoplastic polyolefin, making the mixed system more uniform and stable, but also the antioxidant effectively delays the oxidation of the polymer material, and the ultraviolet absorber prevents the tarpaulin from aging; moreover, during the forming process, the materials can be more fully and evenly mixed to form a stable gradient density structure, effectively improving the overall density and uniformity of the tarpaulin, thereby enhancing the tear resistance and deformation resistance of the tarpaulin in extreme environments, improving the structural integrity and stability, and thus enhancing the weather resistance, protection performance, and service life of the tarpaulin.

[0029] 2. In the weather-resistant polymer composite tarpaulin with a gradient density structure and its preparation method, the control and coordinated operation of each link are as follows: The high-speed mixer preliminarily mixes the raw materials at a specified speed and time, making the full melting and compatibilization of the materials in the subsequent twin-screw extruder more uniform; The multi-layer co-extrusion die promotes the formation of a stable gradient density structure of the materials by controlling the number of flow channels, temperature, extrusion speed, and pressure, effectively improving the structural stability of the tarpaulin; The heat treatment after forming can completely eliminate the residual stress inside the tarpaulin, improving its stability and mechanical properties, while the weather-resistant coating on the surface further enhances the protective performance of the tarpaulin, enabling it to better resist external erosion such as ultraviolet rays, abrasion, and pollution, thereby improving the quality and practicality of the tarpaulin. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] Figure 1 It is a flow chart of the preparation method of the weather-resistant polymer composite tarpaulin with a gradient density structure of the present invention. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0031] Next, the technical solutions in the embodiments of the present invention will be clearly and completely described in conjunction with the drawings in the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments in the present invention, all other embodiments obtained by those skilled in the art without creative efforts belong to the protection scope of the present invention.

[0032] The embodiment of the present invention provides a weather-resistant polymer composite tarpaulin with a gradient density structure, including the following raw materials:

[0033] The dosage of styrene-butadiene rubber (SBR) accounts for 24%-30% of the total mass. Styrene-butadiene rubber has good flexibility and elasticity;

[0034] The dosage of thermoplastic polyolefin (TPO) accounts for 50%-60% of the total mass;

[0035] The dosage of compatibilizer accounts for 7%-12% of the total mass. The compatibilizer can enhance the bonding force and compatibility between styrene-butadiene rubber and thermoplastic polyolefin;

[0036] The dosage of additives accounts for 5%-10% of the total mass. The additives include antioxidants, ultraviolet absorbers, and fillers, where:

[0037] The dosage of antioxidant accounts for 0.8%-1.8% of the total mass. The antioxidant adopts hindered phenol antioxidants, which can effectively delay the oxidation of polymer materials during processing and use;

[0038] The dosage of the ultraviolet absorber accounts for 0.8%-1.8% of the total mass. The ultraviolet absorber adopts benzophenone ultraviolet absorbers, which can absorb ultraviolet rays and prevent the tarpaulin from aging.

[0039] The dosage of the filler accounts for 4%-7% of the total mass. The filler includes at least calcium carbonate and talcum powder, which can not only reduce the cost, but also improve the rigidity and dimensional stability of the tarpaulin.

[0040] According to Figure 1 As shown, the embodiment of the present invention also provides a forming process for preparing the above-mentioned weather-resistant polymer composite tarpaulin with a gradient density structure, including the following steps:

[0041] S1. Raw material preparation: styrene-butadiene rubber, thermoplastic polyolefin, compatibilizer and additives. The compatibilizer adopts maleic anhydride grafted thermoplastic polyolefin (TPO-g-MAH).

[0042] S2. Blending: Add styrene-butadiene rubber, thermoplastic polyolefin, compatibilizer and additives into a high-speed mixer. The initial mixing speed of the high-speed mixer is 800r / min - 120r / min, and the initial mixing time is 6min - 10min, so that each component moves fully and is evenly distributed in the mixer to achieve the effect of initial uniform mixing. Then, transfer the preliminarily mixed material to a twin-screw extruder. The twin-screw extruder adopts a parallel co-rotating twin-screw extruder. The two screws of the parallel co-rotating twin-screw extruder are parallel and rotate in the same direction. Its mixing and shearing effects can promote the uniform dispersion of each component, and can also make the material reach the molten state and undergo a compatibilization reaction. The temperature of the twin-screw extruder is controlled at 190℃ - 220℃, and the screw speed is 210r / min - 240r / min, so that the material is fully mixed and melted in the extruder for 15min - 20min to obtain a uniformly mixed material.

[0043] S3. Gradient density structure construction: Use a mold with a gradient structure. The mold with a gradient structure can adopt a multi-layer co-extrusion mold. The number of flow channels of the mold is 5 - 8 layers. The temperature at the inlet of the mold is 220℃ - 230℃, and the temperature at the outlet of the mold is 180℃ - 190℃. At this time, extrude the uniformly mixed material into the interior of the mold through the twin-screw extruder. The extrusion speed of the twin-screw extruder is 5kg / h - 9kg / h, and the extrusion pressure is 13MPa - 17MPa, so that the material can flow and form uniformly and stably in the mold.

[0044] S4. Forming: When the material forms a stable gradient density structure in the mold with a gradient structure, use a flat extrusion method or a blow molding extrusion method for extrusion, so that the material with a gradient density structure is extruded from the die orifice of the mold to obtain a tarpaulin.

[0045] S5. Post-treatment: Put the formed tarpaulin into a heat treatment device for heat treatment. The heat treatment temperature of the heat treatment device is 105°C - 115°C, and the heat treatment time of the heat treatment device is 40 min - 50 min to eliminate the residual stress inside the tarpaulin, improve its stability and mechanical properties, and make the tarpaulin more durable during use. After heat treatment, take out the tarpaulin from the heat treatment device and let it cool naturally. Then, evenly coat a layer of weather-resistant coating on the surface of the tarpaulin by spraying to form a protective film, which can effectively improve the anti-ultraviolet, anti-wear and anti-pollution capabilities of the tarpaulin, and then a weather-resistant polymer composite tarpaulin with a gradient density structure can be obtained.

[0046] In the invention, firstly, by the dosage ratios of styrene-butadiene rubber (SBR), thermoplastic polyolefin (TPO), maleic anhydride grafted thermoplastic polyolefin (TPO-g-MAH) compatibilizer and additives composed of antioxidant, ultraviolet absorber and filler, not only can the compatibilizer enhance the bonding force and compatibility between styrene-butadiene rubber and thermoplastic polyolefin, but also the antioxidant can effectively delay the oxidation of the polymer material during processing and use, and the ultraviolet absorber can absorb ultraviolet rays to prevent the tarpaulin from aging, thereby improving the comprehensive performance of the tarpaulin. At the same time, the raw material ratios enable the materials to be more fully and evenly mixed in the high-speed mixer and twin-screw extruder during the blending stage in the subsequent forming process. Furthermore, during the construction of the gradient density structure, the flow of the materials in the multi-layer coextrusion die with 5 - 8 flow channels is more stable, forming a gradient density structure, which can also effectively improve the overall density and uniformity of the tarpaulin, further enhancing its anti-tearing and anti-deformation capabilities in extreme environments such as strong wind, heavy snow, high temperature and high humidity, improving the structural integrity and stability of the tarpaulin, and thus enhancing the weather resistance, protection performance and service life of the tarpaulin.

[0047] When styrene-butadiene rubber (SBR), thermoplastic polyolefin (TPO), and maleic anhydride-grafted thermoplastic polyolefin (TPO-g-MAH) are mixed, it can enhance the bonding force and compatibility between SBR and TPO, make the mixed system uniform and stable, improve the comprehensive performance of the tarpaulin, and enhance the structural stability and anti-deformation ability of the tarpaulin in extremely harsh environments such as strong winds and heavy snow, reduce surface scratches and wear, and improve weather resistance and service life. The reaction mechanism is as follows: Under high temperature and the shearing action of a twin-screw extruder, the maleic anhydride group in TPO-g-MAH undergoes a nucleophilic addition reaction with active sites such as double bonds on the SBR molecular chain to form new chemical bonds and achieve chemical bonding; at the same time, TPO-g-MAH and TPO are closely connected through physical interactions such as van der Waals forces, hydrogen bonds, and mutual diffusion and entanglement of some chain segments due to their similar molecular structures; Taking the reaction between TPO-g-MAH and the double bond in SBR as an example, the chemical reaction formula is: TPO-g-MAH + SBR (containing double bond) → -C-C-O-CO- (addition product), that is, the anhydride ring of maleic anhydride opens and undergoes an addition reaction with the double bond on the SBR molecular chain, thereby achieving the compatibilization effect.

[0048] In addition, under high temperature and the shearing action of a twin-screw extruder, the maleic anhydride group in TPO-g-MAH undergoes a nucleophilic addition reaction with the double bond on the SBR molecular chain to form a new addition product containing ester groups and other structures. Taking the reaction between the 1,3-butadiene structural unit and maleic anhydride as an example, the chemical reaction formula can be expressed as: CH2=CH-CH=CH2 + C4H2O3 → CH2-CH(COO-)-CH2-C(=O)-O- (Note: In the actual reaction, the SBR molecular chain is a long-chain structure, which is simplified to the 1,3-butadiene structural unit here to represent the reaction principle). The newly formed chemical bond enables a chemical bond to form between SBR and TPO-g-MAH. Coupled with the close connection between TPO-g-MAH and TPO through physical interactions, this not only makes the mixed system more uniform and stable but also enhances the structural strength inside the tarpaulin; on the one hand, it allows the materials to be more fully and evenly mixed in a high-speed mixer and a twin-screw extruder, facilitating the formation of a stable gradient density structure and improving the overall density and uniformity of the tarpaulin; on the other hand, the synergy of this chemical bonding and physical interaction effectively enhances the mechanical properties of the tarpaulin, such as tear resistance and anti-deformation ability.

[0049] The maleic anhydride groups in its molecule can undergo nucleophilic addition reactions with active sites such as double bonds on the molecular chains of styrene-butadiene rubber (SBR) to form new chemical bonds, achieving chemical bonding. At the same time, due to the similar molecular structures of TPO-g-MAH and thermoplastic polyolefin (TPO), they are closely connected through physical interactions such as van der Waals forces, hydrogen bonds, and the mutual diffusion and entanglement of some chain segments between molecules. These direct effects make the mixed system more uniform and stable, which helps the materials to be more fully and evenly mixed in the high-speed mixer and twin-screw extruder, and flow more stably in the multi-layer coextrusion die, facilitating the formation of a gradient density structure.

[0050] By adjusting the raw material ratio and preparation process, the effect of improving the comprehensive performance of the tarpaulin is not only achieved by enhancing the bonding force and compatibility between styrene-butadiene rubber and thermoplastic polyolefin through the compatibilizer, making the mixed system more uniform and stable, but also by effectively delaying the oxidation of the polymer material through the antioxidant and preventing the tarpaulin from aging by using the ultraviolet absorber. Moreover, during the forming process, the materials can be more fully and evenly mixed to form a stable gradient density structure, effectively improving the overall density and uniformity of the tarpaulin, thereby enhancing the tear resistance and deformation resistance of the tarpaulin in extreme environments, improving the structural integrity and stability, and thus enhancing the weather resistance, protection performance and service life of the tarpaulin.

[0051] Through the control and coordinated operation of each link, the high-speed mixer preliminarily mixes the raw materials at a specified speed and time, making the subsequent melting and compatibilization of the materials in the twin-screw extruder more uniform; the multi-layer coextrusion die promotes the formation of a stable gradient density structure of the materials by controlling the number of flow channels, temperature, extrusion speed and pressure, effectively improving the structural stability of the tarpaulin; the heat treatment after forming can completely eliminate the residual stress inside the tarpaulin and improve its stability and mechanical properties, while the weather-resistant coating on the surface further enhances the protection performance of the tarpaulin, enabling it to better resist external erosion such as ultraviolet rays, abrasion and pollution, thereby improving the quality and practicality of the tarpaulin.

[0052] According to different raw material dosages, the weather-resistant polymer composite tarpaulin with a gradient density structure provided by the present invention is further described through the following specific embodiments.

[0053] Example 1

[0054] Raw material ratio: The dosage of styrene-butadiene rubber accounts for 24% of the total mass; the dosage of thermoplastic polyolefin accounts for 59% of the total mass; the dosage of compatibilizer accounts for 10% of the total mass; the dosage of additives accounts for 7% of the total mass, among which the dosage of antioxidant accounts for 1% of the total mass, the dosage of ultraviolet absorber accounts for 1% of the total mass, and the dosage of filler accounts for 5% of the total mass.

[0055] Forming process: Add the raw materials into a high-speed mixer and mix them preliminarily at a speed of 800 r / min for 6 min. Then transfer them into a co-rotating twin-screw extruder, control the temperature at 190 °C, and the screw speed at 210 r / min to fully mix and melt the materials for 15 min. Use a multi-layer co-extrusion die with a gradient structure (the number of flow channels is 5 layers), the temperature at the die inlet is 220 °C, and the temperature at the die outlet is 180 °C. Extrude the materials through the twin-screw extruder at a speed of 6 kg / h, and the extrusion pressure is 13 MPa. Adopt a flat extrusion method to extrude and obtain the tarpaulin. Put the tarpaulin into a heat treatment device and treat it at 105 °C for 40 min. After natural cooling, spray a weather-resistant coating on the surface of the tarpaulin.

[0056] Example 2

[0057] Raw material ratio: The dosage of styrene-butadiene rubber accounts for 28% of the total mass; the dosage of thermoplastic polyolefin accounts for 52% of the total mass; the dosage of compatibilizer accounts for 12% of the total mass; the dosage of additives accounts for 8% of the total mass, among which the dosage of antioxidant accounts for 1.1% of the total mass, the dosage of ultraviolet absorber accounts for 1.1% of the total mass, and the dosage of filler accounts for 5.8% of the total mass.

[0058] Forming process: Add the raw materials into a high-speed mixer and mix them preliminarily at a speed of 1000 r / min for 8 min. Then transfer them into a co-rotating twin-screw extruder, control the temperature at 205 °C, and the screw speed at 225 r / min to fully mix and melt the materials for 18 min. Use a multi-layer co-extrusion die with a gradient structure (the number of flow channels is 6 layers), the temperature at the die inlet is 225 °C, and the temperature at the die outlet is 185 °C. Extrude the materials through the twin-screw extruder at a speed of 9 kg / h, and the extrusion pressure is 17 MPa. Adopt a blow molding extrusion method to extrude and obtain the tarpaulin. Put the tarpaulin into a heat treatment device and treat it at 110 °C for 45 min. After natural cooling, spray a weather-resistant coating on the surface of the tarpaulin.

[0059] Example 3

[0060] Raw material ratio: The dosage of styrene-butadiene rubber accounts for 30% of the total mass; the dosage of thermoplastic polyolefin accounts for 56% of the total mass; the dosage of compatibilizer accounts for 8% of the total mass; the dosage of additives accounts for 6% of the total mass, among which the dosage of antioxidant accounts for 0.8% of the total mass, the dosage of ultraviolet absorber accounts for 0.8% of the total mass, and the dosage of filler accounts for 4.4% of the total mass.

[0061] Forming process: Add the raw materials into a high-speed mixer and mix them preliminarily at a speed of 1200 r / min for 10 min. Then transfer them into a co-rotating twin-screw extruder, control the temperature at 220 °C, and the screw speed at 240 r / min to fully mix and melt the materials for 20 min. Use a multi-layer co-extrusion die with a gradient structure (8 layers of flow channels), the temperature at the die inlet is 230 °C, and the temperature at the outlet is 190 °C. Extrude the materials through the twin-screw extruder at a speed of 7 kg / h, and the extrusion pressure is 16 MPa. Adopt a flat extrusion method to obtain the tarpaulin. Put the tarpaulin into a heat treatment device and treat it at 115 °C for 50 min. After natural cooling, spray weather-resistant coating on the surface of the tarpaulin.

[0062] Table 1 Raw material dosages of Examples 1 - 3

[0063] Example 1 Example 2 Example 3 Styrene-butadiene rubber (%) 24 28 30 Thermoplastic polyolefin (%) 59 52 56 Compatibilizer (%) 10 12 8 Additive (%) 7 8 6

[0064] In order to verify that the weather-resistant polymer composite tarpaulin prepared in the examples of the present invention has good weather resistance and mechanical properties, the following test examples are used to illustrate the weather-resistant polymer composite tarpaulin with a gradient density structure provided in the examples of the present invention.

[0065] Test examples

[0066] The purpose of this test group is to explore the influence of different component ratios on the weather-resistant polymer composite tarpaulin with a gradient density structure, and to detect the weather resistance, tear resistance, anti-deformation ability, structural stability, protection, density and uniformity of the weather-resistant polymer composite tarpaulin with a gradient density structure of the present invention.

[0067] Test objectives: Test groups A, B, and C respectively adopt the component ratios of the weather-resistant polymer composite tarpaulins with a gradient density structure provided in Examples 1 - 3; the control examples adopt control groups A, B, C, and D, where:

[0068] Control group A

[0069] Raw material ratio: The same as that in Example 1, but without adding a compatibilizer;

[0070] Forming process: The same as that in Example 1, but remove the step of adding a compatibilizer, and the number of flow channels of the multi-layer co-extrusion die with a gradient structure is 9 layers.

[0071] Control group B

[0072] Raw material ratio: The dosage of thermoplastic polyolefin (TPO) accounts for 100% of the total mass;

[0073] Forming process: Directly pass the TPO raw material through an extrusion molding device. Carry out molding according to the conventional extrusion temperature of 180°C and an extrusion speed of 3 kg / h. Use a multi-layer co-extrusion die with a gradient structure. The number of flow channels is 3 layers. The temperature at the die inlet is 200°C, and the temperature at the outlet is 170°C. The extrusion pressure of the twin-screw extruder is set at 10 MPa. Obtain the tarpaulin by using a flat extrusion method.

[0074] Control group C

[0075] Raw material composition: Woven grid cloth, TPU film, PUR glue layer. The dosage of the woven grid cloth accounts for 40% of the total mass, the dosage of the TPU film accounts for 50% of the total mass, and the dosage of the PUR glue layer accounts for 10% of the total mass;

[0076] Forming process: Coat the PUR glue layer on the woven grid cloth and the TPU film respectively; Carry out melt bonding on the woven grid cloth and the TPU film coated with the glue layer. Use a traditional twin-screw extruder. Set the extrusion temperature at 160°C, the extrusion speed at 4 kg / h, and the extrusion pressure at 8 MPa to form a composite tarpaulin.

[0077] Control group D

[0078] Raw material ratio: The same as in Example 3;

[0079] Forming process: Add the raw materials into a high-speed mixer and mix them preliminarily at a speed of 1200 r / min for 10 min. Then transfer them into a co-rotating twin-screw extruder. Control the temperature at 220°C and the screw speed at 240 r / min to fully mix and melt the materials for 20 min; Use a multi-layer co-extrusion die with a gradient structure (the number of flow channels is 8 layers). The temperature at the die inlet is 230°C, and the temperature at the outlet is 190°C. Extrude the materials at a speed of 12 kg / h through the twin-screw extruder. The extrusion pressure of the twin-screw extruder is 10 MPa. Carry out extrusion by using a flat extrusion method to obtain the tarpaulin; Put the tarpaulin into a heat treatment device and treat it at 115°C for 50 min. After natural cooling, spray weather-resistant coating on the surface of the tarpaulin.

[0080] Test method: Conduct tests respectively according to the weather resistance, tear resistance, anti-deformation ability, structural stability, protection, density and uniformity of the weather-resistant polymer composite tarpaulin with a gradient density structure of the present invention. The specific test methods are as follows:

[0081] Weather resistance test method: Place the tarpaulin samples of experimental groups A, B, C and control groups A, B, C, D in a weather resistance test chamber respectively; Set the environmental parameters in the test chamber: The ultraviolet radiation intensity is 600 W / m 2, the temperature cyclically varies between -30°C and 70°C (one cycle every 3 h, with the high temperature of 70°C maintained for 1.5 h and the low temperature of -30°C maintained for 1.5 h), the humidity is kept at 85% ± 5%, and at the same time, there is periodic rain (once every 3 h, lasting for 1 h each time) and wind blowing (wind speed of 12 m / s, once every 5 h, lasting for 1.5 h each time); the test duration is 1200 h. Samples are taken out every 120 h for appearance inspection, and the surface fading degree (using the gray scale standard, level 1 means no fading, and level 5 means severe fading), the number and length of cracks (the number of cracks per square centimeter and the longest crack length), and the powdering situation (evaluated visually, divided into none, slight, moderate, and severe) are recorded. At the same time, its tensile strength and elongation at break are measured (tested according to relevant standards), and the change rate is calculated by comparing with the initial value to comprehensively evaluate the weather resistance of the tarpaulin.

[0082] Table 2 Weather Resistance Detection Indexes

[0083]

[0084] Tear Resistance Test Method: Specimens with dimensions of 250 mm × 120 mm are respectively cut from the tarpaulin samples of experimental groups A, B, C and control groups A, B, C, D. An electronic universal testing machine is used for the tear resistance test. One end of the specimen is fixed on the fixture of the testing machine, and a tensile force perpendicular to the edge of the specimen is applied at the other end. The tensile speed is set at 60 mm / min; when the specimen is torn, the maximum tensile force value (unit: N) is recorded. To reduce errors, each sample is tested 7 times repeatedly, and the average value is taken as the final tear resistance force to measure the tear resistance performance of the tarpaulin. The larger the value, the better the tear resistance.

[0085] Table 3 Tear Resistance Detection Indexes

[0086] Test Group A Test Group B Test Group C Control Group A Control Group B Control Group C Control Group D Tear resistance (N) 300 340 370 160 210 230 260

[0087] Deformation Resistance Test Method: The tarpaulin samples of experimental groups A, B, C and control groups A, B, C, D are subjected to deformation tests simulating actual use; the tarpaulin samples are fixed on an adjustable frame, and a uniformly distributed pressure is applied on the surface of the tarpaulin to simulate strong wind or heavy object pressing; the pressure size is set at 600 Pa. After maintaining the pressure for 1.5 h, a high-precision measuring instrument (such as a 3D scanner) is used to measure the maximum deformation amount (unit: mm) on the surface of the tarpaulin; at the same time, after removing the pressure, the time (unit: min) required for the tarpaulin to return to its original shape is recorded, and the recovery degree (the ratio of the recovered size to the original size) is calculated to evaluate the deformation resistance ability of the tarpaulin.

[0088] Table 4 Deformation Resistance Detection Indexes

[0089] Test Group A Test Group B Test Group C Control Group A Control Group B Control Group C Control Group D Maximum deformation (mm) 4 2 1 12 9 8 6 Recovery time (min) 8 6 4 25 18 16 12 Recovery degree (%) 92 96 98 60 75 82 88

[0090] Structural stability test method: Use a vibration test device to conduct structural stability tests on the tarp samples of test groups A, B, C and control groups A, B, C, D; fix the tarp samples on the vibration table, set the vibration frequency to 12 Hz, the amplitude to 6 mm, and the vibration time to 2.5 h; during the vibration process, use a high-speed camera to observe the structural changes of the tarp in real time, and pay special attention to whether cracks and delaminations occur at the edges, seams and inside of the tarp; after the vibration ends, check the overall structural integrity of the tarp, and record the number and length of cracks (unit: mm) and the delamination area (unit: cm 2 ), and use this to evaluate the structural stability of the tarp.

[0091] Table 5 Structural stability detection indicators

[0092] Test Group A Test Group B Test Group C Control Group A Control Group B Control Group C Control Group D Number of cracks (pcs) 1 0 0 7 5 4 3 Crack length (mm) 1 0 0 4 3 2.5 2 <![CDATA[Delamination area (cm 2 )]]> 0 0 0 8 5 4 2

[0093] Protective test method: Cover the tarp samples of test groups A, B, C and control groups A, B, C, D on the same simulated protected object respectively (such as a metal plate with a special coating on the surface, and the coating can change color when eroded to indicate the protection effect), simulating the actual use scenario; conduct different types of external erosion simulations on the protected object: use a high-pressure water gun to spray water to simulate heavy rain scouring (water pressure 6 MPa, lasting 40 min), and use sand grains ejected by a grinding wheel to simulate sandstorm erosion (sand grain diameter 0.6 mm, ejection speed 35 m / s, lasting 20 min); after a series of erosions, check the color change of the surface of the protected object, calculate the degree of color change (using a color difference measuring instrument, unit: ΔE), and use this to evaluate the protection effect of the tarp on the object. The smaller the color difference, the better the protection.

[0094] Table 6 Protective detection indicators

[0095]

[0096] Density test method: Use a density measuring instrument to conduct density tests on the tarp samples of test groups A, B, C and control groups A, B, C, D; cut small samples with a size of 60 mm×60 mm from different parts of the tarp samples (center, edge, four corners, a total of 6 parts), measure the mass of each small sample (unit: g) and volume (measured by the drainage method, unit: cm 3 ); calculate the density of each small sample by the ratio of mass to volume (unit: g / cm 3 ), and then calculate the average value of the densities of all small samples as the average density of the tarp. Let the densities of n (here (n = 6)) small samples cut from different parts of the tarp sample be ρ1, ρ2,..., ρn , the average density The calculation formula is: At the same time, calculate the standard deviation of the density of each small sample. The standard deviation S is used to measure the degree of dispersion of a set of data. For the densities ρ1, ρ2,..., ρ of the above n small samples n , the calculation formula of its standard deviation S is: Among them, is the average value of the densities of these n small samples, ρ i is the density of the i-th small sample, and n is the number of small samples; the smaller the standard deviation, the more uniform the density of the tarpaulin and the higher the density.

[0097] Table 7 Density detection index

[0098]

[0099] Uniformity test method: Use an optical microscope to observe the microstructure of the tarpaulin samples of experimental groups A, B, C and control groups A, B, C, D; Cut thin samples with a size of 12mm×12mm from different parts (at least 6 different positions) of the tarpaulin samples, place the samples under the microscope, and the magnification is 250 times; Observe the internal fiber distribution and the microstructure of particle arrangement, and process the observed images through image analysis software to measure the fiber spacing (unit: μm) and particle concentration (unit: pieces / mm 2 ); Calculate the coefficient of variation of these microstructure parameters (coefficient of variation = standard deviation / average value). The smaller the coefficient of variation, the more uniform the microstructure of the tarpaulin and the better the overall uniformity.

[0100] Table 8 Uniformity detection index

[0101]

[0102] According to Table 2 - Table 8, the summary of the above comparison data is as follows:

[0103] In terms of weather resistance: The weather resistance of the tarpaulins in experimental groups A, B, and C is higher than that in control groups A, B, C, and D. There are basically no fading, cracking, and powdering phenomena in experimental groups B and C. Experimental group A also shows good performance, and the change rates of tensile strength and elongation at break are relatively small. This is mainly due to the raw material ratio of the tarpaulins in the experimental groups. The compatibilizer enhances the combination of styrene-butadiene rubber and thermoplastic polyolefin, the antioxidant delays oxidation, the ultraviolet absorber prevents aging, and at the same time, a stable gradient density structure is formed during the molding process, improving the overall density and uniformity of the tarpaulin, thereby effectively resisting the erosion of the external environment. Compatibilizer is not added in control group A, resulting in poor bonding force and compatibility between styrene-butadiene rubber and thermoplastic polyolefin. Under the action of external environmental factors, the two materials are prone to separation, delamination, etc., leading to more cracks and serious powdering on the surface of the tarpaulin, and at the same time, the change rates of tensile strength and elongation at break are large, and the weather resistance is significantly reduced; only thermoplastic polyolefin is used in control group B, with single performance, and the tarpaulin is prone to damage when facing a complex external environment; traditional raw materials and processes are used in control group C, with limited protective performance, and the extrusion speed and pressure are low. Due to different materials for each layer, the tightness and overall stability of the internal structure of the tarpaulin are reduced, resulting in a decline in its weather resistance. Although the raw material ratio in control group D is the same as that in Example 3, the process parameters of extrusion speed and pressure are different, which will affect the mixing uniformity and densification degree of the material during the molding process, resulting in a decline in the density and uniformity of the internal structure of the tarpaulin.

[0104] Tear resistance: The tear resistance of the tarpaulins in experimental groups A, B, and C is significantly higher than that in control groups A, B, C, and D. Among the experimental groups, the maximum tear force in experimental group C is 370 N, and those in experimental groups A and B are 300 N and 340 N respectively. The tear forces of control groups A, B, C, and D are all lower than those in the experimental groups, and the tear force in control group A is only 160 N. The specific principle is that compatibilizer is not added in control group A, and the bonding force between styrene-butadiene rubber and thermoplastic polyolefin is insufficient. When being torn by external force, the two materials are easy to separate, resulting in poor tear resistance of the tarpaulin; only thermoplastic polyolefin is used in control group B, lacking the synergistic strengthening effect of other materials, and the toughness and strength of the material itself are limited, with poor tear resistance; traditional raw materials and processes are used in control group C, and the bonding effect between the woven grid cloth, TPU film, and PUR glue layer is limited, and the extrusion speed and pressure are low, making the internal structure of the tarpaulin not tight enough and prone to tearing along the bonding interface when stressed; although the raw material ratio in control group D is the same as that in Example 3, the extrusion speed of the twin-screw extruder is too fast (12 kg / h) and the pressure is low (10 MPa), which affects the mixing uniformity and densification degree of the material during the molding process, resulting in an insufficiently dense and non-uniform internal structure of the tarpaulin and a decline in tear resistance.

[0105] Anti-deformation ability: The tarpaulins of experimental groups A, B, and C are superior to those of control groups A, B, C, and D in terms of anti-deformation ability. The maximum deformation of experimental group C is the smallest, only 1 mm, the recovery time is the shortest, 4 min, and the recovery degree is the highest, reaching 98%; experimental groups A and B also perform well. The maximum deformation of control group A is 12 mm, the recovery time is 25 min, and the recovery degree is only 60%. The situations of other control groups are similar and all are inferior to the experimental groups. The specific principle is that since no compatibilizer is added to control group A, the bonding between materials is unstable. When under pressure, it is easy to produce large deformations and is difficult to recover; the single thermoplastic polyolefin material in control group B lacks elasticity and toughness and cannot effectively resist deformation; for control group C, due to traditional raw materials and processes, the internal structure of the tarpaulin is not tight enough, and the bonding parts are prone to deformation and damage under pressure, and the low extrusion speed and pressure result in insufficient density of the tarpaulin; for control group D, the extrusion speed is too fast and the pressure is low, resulting in uneven mixing of materials, a decrease in the density of the internal structure of the tarpaulin, and a weakening of the anti-deformation ability.

[0106] Structural stability: The tarpaulins of experimental groups B and C have the best structural stability, without cracks and delamination. There is only 1 crack in experimental group A and no delamination; while in control groups A, B, C, and D, different degrees of cracks and delamination occur. Control group A has the largest number of cracks, 7, and the largest delamination area, 8 cm 2 . The specific principle lies in that since no compatibilizer is added to control group A, the bonding force between materials is weak. Under the action of vibration, relative displacement is likely to occur between different materials, resulting in cracks and delamination; the structural stability of the single material in control group B is limited and cannot effectively resist the influence brought by vibration; for control group C, due to traditional raw materials, low extrusion speed, and low pressure, the stability of the internal structure of the tarpaulin is insufficient, and the bonding parts are prone to separation under vibration; although the raw material ratio of control group D is the same as that of Example 3, the extrusion speed of the twin-screw extruder is too fast (12 kg / h) and the pressure is low (10 MPa). This will lead to a shortened residence time of the material in the twin-screw extruder, making it difficult to fully melt and mix evenly within a limited time, resulting in uneven distribution of each component inside the tarpaulin. During the vibration process, these uneven component distributions and tiny gaps will become weak points, causing stress concentration, leading to cracks more easily generated at the edges, seams, and inside of the tarpaulin. Moreover, due to the weak bonding between layers, under the external force of vibration, relative displacement is extremely likely to occur between each layer, thus resulting in delamination.

[0107] Protection: The protective performance of the tarpaulins in the test groups A, B, and C is better than that in the control groups A, B, C, and D. The test group C has the best protection, with the smallest color difference of 370, and the test groups A and B are also relatively small; while the color difference of the control groups A, B, C, and D is large, and the color difference of the control group A is 160, and the protective effect is poor. The specific principle is that the control group A did not add a volume expander, and the tarpaulin was easily separated from the materials under external erosion. The multi-layer co-extrusion mold had 9 layers of flow channels, but the structure was easily destroyed, and it could not effectively block the corrosive substances, and the protective performance decreased; the control group B had a single thermoplastic polyolefin material with limited protective function, and the multi-layer co-extrusion mold had 3 layers of flow channels, which made it difficult to achieve uniform compaction and fusion through the adjustment and distribution of more flow channels when the material flowed in the mold, resulting in the internal structure of the tarpaulin not being dense enough, with many pores and weak areas, and external corrosive substances could easily invade through these parts, thus affecting the overall performance of the tarpaulin. The protective performance of the control group C is good; the traditional raw materials and the lower extrusion speed and pressure make the tarpaulin structure not tight enough, with gaps, which make it easy for external corrosive substances to enter and affect the protective effect; the control group D has an overly fast extrusion speed and low pressure, which leads to the inability to fully mix and compact the materials during the molding process, resulting in insufficient density and uniformity of the internal structure of the tarpaulin, and there are many gaps and uneven structural areas. These gaps and uneven areas become channels for external corrosive substances to enter the interior of the tarpaulin, thereby reducing the tarpaulin's ability to protect the protected objects and failing to effectively prevent damage to the protected objects by external factors.

[0108] Density: The density of the tarpaulins in the test groups A, B, and C is higher than that in the control groups A, B, C, and D. The average density of the test group C is the highest, which is 1.32g / cm 3, the standard deviation is the smallest, which is 0.025, and the density is the most uniform; experimental groups A and B also perform well; while the average densities of control groups A, B, C, and D are relatively low, the standard deviations are relatively large, and the density is relatively poor. The specific principle is that no compatibilizer is added to control group A, and the materials are not evenly mixed. The number of flow channels in the multi-layer co-extrusion die is 9 layers, which seems complex. However, due to the lack of the action of the compatibilizer, it is difficult for the materials to be fully fused, resulting in a loose internal structure and many voids during the forming process of the tarpaulin, thus causing the density to decrease; control group B uses a single material. During the forming process, the parameter settings such as temperature and speed are not reasonable enough, and the performance advantages of the material cannot be fully exerted. At the same time, the number of flow channels in the multi-layer co-extrusion die is only 3 layers, which makes the material lack sufficient layer interleaving and close packing during the flow and forming processes, further affecting the density of the tarpaulin; control group C uses traditional raw materials and a relatively low extrusion speed and pressure, making the internal structure of the tarpaulin not tight enough and having many voids, resulting in a decrease in density; although the raw material ratio of control group D is the same as that in some cases of the experimental group, the extrusion speed is too fast, making the residence time of the material in the twin-screw extruder too short to be fully mixed; at the same time, the pressure is relatively low and cannot effectively compact the material. The combined action of these two factors causes the material to not be fully mixed and compacted during the forming process, and then makes the density of the internal structure of the tarpaulin uneven, and the density difference between different parts is relatively large.

[0109] Uniformity: The microstructural uniformity of the tarpaulins in experimental groups A, B, and C is superior to that in control groups A, B, C, and D. The coefficient of variation of experimental group C is the smallest, at 0.07, indicating the most uniform microstructure; those of experimental groups A and B are also relatively small; while the coefficients of variation of control groups A, B, C, and D are relatively large, with the coefficient of variation of control group A being 0.28, showing poor uniformity. The specific principle is as follows: In control group A, due to the absence of a compatibilizer, there is a lack of effective connection and compatibilization mechanisms between styrene-butadiene rubber and thermoplastic polyolefins. Although the number of flow channels in the multi-layer coextrusion die is 9 layers, due to the poor compatibility between materials, different materials cannot be fully fused during the blending and extrusion processes, resulting in a chaotic distribution of fibers and particle arrangement in the microstructure, severely damaging the uniformity. Control group B uses only a single thermoplastic polyolefin material, and its microstructure is relatively simple, lacking the complementary and optimization effects brought about by the synergistic action of multiple materials. Moreover, the number of flow channels in the multi-layer coextrusion die is only 3 layers, and the materials cannot be more finely regulated and distributed through multi-layer coextrusion, further exacerbating the non-uniformity of the microstructure. Control group C uses traditional raw materials, and the interaction and combination methods between these raw materials are relatively limited. At the same time, the low extrusion speed and pressure prevent the materials from being sufficiently sheared and dispersed during the forming process, making it difficult for molecular chains and particles to achieve a uniform arrangement and distribution. Although the raw material ratio in control group D is the same as that in a certain situation in the experimental group, due to the too-fast extrusion speed and low pressure, the residence time of the materials in the twin-screw extruder is insufficient, and the mixing process is not sufficient, making it impossible to achieve uniform dispersion and interaction of each component. This results in the microstructure of the tarpaulin being difficult to reach a uniform state during the subsequent forming process, leading to a decrease in microstructural uniformity.

[0110] In summary, through the selection and proportioning of raw materials, the compatibilizer enhances the bonding force and compatibility between styrene-butadiene rubber and thermoplastic polyolefin. The antioxidant effectively delays the oxidation of polymer materials. The ultraviolet absorber prevents the tarpaulin from aging. The filler improves the rigidity and dimensional stability of the tarpaulin. At the same time, the proportion of raw materials enables the materials to be more fully and evenly mixed during the molding process, forming a stable gradient density structure, effectively improving the overall density and uniformity of the tarpaulin, thereby enhancing the weather resistance, tear resistance, anti-deformation ability, structural stability, protection performance, etc. of the tarpaulin. And, during the preparation process, the extrusion speed (5-9 kg / h) and pressure (13-17 MPa) of the twin-screw extruder are restricted, enabling the materials to be fully mixed and melted, forming a uniform and stable structure, avoiding structural defects caused by too fast speed or improper pressure, and further improving the performance of the tarpaulin. In addition, from the test results, the optimal proportion is the proportion of Example 3 (the dosage of styrene-butadiene rubber accounts for 30% of the total mass; the dosage of thermoplastic polyolefin accounts for 56% of the total mass; the dosage of compatibilizer accounts for 8% of the total mass; the dosage of additives accounts for 6% of the total mass, among which, the dosage of antioxidant accounts for 0.8% of the total mass, the dosage of ultraviolet absorber accounts for 0.8% of the total mass, and the dosage of filler accounts for 4.4% of the total mass).

[0111] The above shows and describes the basic principles, main features and advantages of the present invention. Those skilled in the art should understand that the present invention is not limited by the above embodiments. The above embodiments and the descriptions in the specification are only preferred examples of the present invention and are not used to limit the present invention. Without departing from the spirit and scope of the present invention, the present invention will have various changes and improvements, and these changes and improvements all fall within the scope of the present invention claimed. The scope of protection claimed by the present invention is defined by the appended claims and their equivalents.

Claims

1. A molding process for a weather-resistant polymer composite tarpaulin with a gradient density structure, characterized in that: The following steps are involved: S1. Raw material preparation: styrene-butadiene rubber, thermoplastic polyolefin, compatibilizer and additives, wherein the compatibilizer is used to enhance the bonding force and compatibility between styrene-butadiene rubber and thermoplastic polyolefin; S2, blending: adding styrene-butadiene rubber, thermoplastic polyolefin, compatibilizer and additives into a high-speed mixer for preliminary mixing, and then transferring to a twin-screw extruder for mixing and melting to obtain a material. At this time, the compatibilizer can react with the styrene-butadiene rubber to form a chemical bond for stabilizing the generation of a gradient density structure; S3, gradient density structure construction: using a mold with a gradient structure, the uniformly mixed material is extruded into the mold through a twin-screw extruder at a speed of 5kg / h-9kg / h and a pressure of 13MPa-17MPa; S4, molding: After the material forms a stable gradient density structure, it is extruded by flat extrusion or blow extrusion to obtain a tarpaulin; S5. Post-processing: Place the formed tarpaulin in a heat treatment device for processing, then take it out for natural cooling to obtain the finished tarpaulin.

2. The molding process of the weather-resistant polymer composite tarpaulin with gradient density structure according to claim 1, characterized in that: In the above S1, the compatibilizer is maleic anhydride grafted thermoplastic polyolefin.

3. The molding process of the weather-resistant polymer composite tarpaulin with gradient density structure according to claim 1, characterized in that: In S2, the high-speed mixer performs preliminary mixing at a speed of 800 r / min-120 r / min for 6 min-10 min.

4. The molding process of the weather-resistant polymer composite tarpaulin with gradient density structure according to claim 1, characterized in that: In S2, the twin-screw extruder is a parallel co-rotating twin-screw extruder, the temperature of the twin-screw extruder is controlled at 190°C-220°C, the screw speed is 210r / min-240r / min, and the time for the material to be fully mixed and melted in the extruder is 15min-20min.

5. The molding process of the weather-resistant polymer composite tarpaulin with gradient density structure according to claim 1, characterized in that: In S3, the mold with a gradient structure can be a multi-layer co-extrusion mold, the number of flow channels of the mold is 5-8 layers, the temperature at the inlet of the mold is 220°C-230°C, and the temperature at the outlet of the mold is 180°C-190°C.

6. The molding process of the weather-resistant polymer composite tarpaulin with gradient density structure according to claim 1, characterized in that: In S5, the heat treatment equipment performs heat treatment at a temperature of 105° C. to 115° C. for 40 min to 50 min.

7. A weather-resistant polymer composite tarpaulin with a gradient density structure prepared by the molding process of the weather-resistant polymer composite tarpaulin with a gradient density structure according to any one of claims 1 to 6, characterized in that: Including the following ingredients: The amount of the styrene-butadiene rubber accounts for 24%-30% of the total mass; The amount of the thermoplastic polyolefin accounts for 50%-60% of the total mass; The amount of the compatibilizer is 7%-12% of the total mass; The additive dosage accounts for 5%-10% of the total mass.

8. The weather-resistant polymer composite tarpaulin with gradient density structure according to claim 7, characterized in that: The additives include antioxidants, ultraviolet absorbers and fillers, wherein: The amount of the antioxidant is 0.8%-1.8% of the total mass; The amount of the ultraviolet absorber is 0.8%-1.8% of the total mass; The amount of the filler is 4%-7% of the total mass.

9. The weather-resistant polymer composite tarpaulin with gradient density structure according to claim 8, characterized in that: The antioxidant is a hindered phenol antioxidant; the ultraviolet absorber is a benzophenone ultraviolet absorber; and the filler includes at least calcium carbonate and talcum powder.

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