Polyolefin waterproof rolling material having high dimensional stability and preparation method therefor

Abstract

A polyolefin waterproof rolling material having high dimensional stability and a preparation method therefor. The waterproof rolling material comprises a first polyolefin elastomer layer (1), a reinforcing layer (2) and a second polyolefin elastomer layer (3) which are sequentially stacked, wherein the raw material formulas of the first polyolefin elastomer layer (1) and the second polyolefin elastomer layer (3) each independently comprise a polyolefin elastomer and polypropylene, the viscosity of the polyolefin elastomer is 8000 mPa•s or less, and the melt flow rate of the polypropylene at 230°C and 2.16 kg is 1000 g / 10 min or more. The low-viscosity polyolefin elastomer and the high-melt-flow-rate polypropylene are used in cooperation, so that the overall processing fluidity of the polyolefin elastomer layers is improved, the polyolefin elastomer layers can fully infiltrate the reinforcing layer during extrusion lamination, the situation that the mechanical properties of the polyolefin waterproof rolling material are reduced due to excessive extrusion is avoided, and the prepared polyolefin waterproof rolling material has good mechanical properties while having high dimensional stability.

Description

A polyolefin waterproofing membrane with high dimensional stability and preparation method thereof Technical Field

[0001] The present invention belongs to the technical field of waterproof coiled materials, and in particular relates to a polyolefin waterproof coiled material with high dimensional stability and a preparation method thereof. Background Art

[0002] Polyolefin waterproofing membranes are primarily made from polyolefin elastomers, with fillers and other additives added. However, due to internal stress during production, high temperatures during construction, and exposure to sunlight during use, polyolefin waterproofing membranes are prone to dimensional changes, resulting in surface warping and bulging.

[0003] Chinese patent CN113681996A discloses a TPO waterproofing membrane with reduced shrinkage and its preparation method. The membrane comprises a non-woven fabric, a lower TPO layer, a reinforcement structure, and an upper TPO layer stacked in sequence. The reinforcement structure comprises a glass fiber mat placed horizontally between the lower and upper TPO layers. While this TPO waterproofing membrane is reinforced with glass fiber, which can reduce its shrinkage, the inventors discovered during actual membrane production that while this glass fiber mat-reinforced polyolefin waterproofing membrane reduces shrinkage, its mechanical properties are significantly degraded.

[0004] Summary of the Invention

[0005] Purpose of the invention: In order to solve the problem in the prior art that the mechanical properties of glass fiber mat reinforced polyolefin waterproof membranes are greatly reduced, the present invention provides an improved polyolefin waterproof membrane, which has high dimensional stability and good mechanical properties.

[0006] Technical solution: In order to solve the above technical problems, the present invention adopts the following technical solution:

[0007] A polyolefin waterproofing membrane comprises a first polyolefin elastomer layer, a reinforcement layer, and a second polyolefin elastomer layer stacked in sequence. The raw material formulas of the first polyolefin elastomer layer and the second polyolefin elastomer layer independently include a polyolefin elastomer and polypropylene, the sum of the masses of the polyolefin elastomer and the polypropylene accounts for more than 75% of the total mass of the raw materials of the first polyolefin elastomer layer or the second polyolefin elastomer layer, and the mass ratio of the polyolefin elastomer to the polypropylene is 1:0.3-0.7. The viscosity of the polyolefin elastomer is less than 8000 mPa·s; and the melt flow rate of the polypropylene at 230°C and 2.16 kg is greater than 1000 g / 10 min.

[0008] According to some implementation aspects of the present invention, the viscosity of the polyolefin elastomer is 500 to 8000 mPa·s.

[0009] According to some implementation aspects of the present invention, the elongation at break of the polyolefin elastomer is greater than 800%.

[0010] In the present invention, the polyolefin elastomer refers to a thermoplastic polyolefin elastomer.

[0011] In some specific embodiments, the polyolefin elastomer is selected from propylene-based elastomers, and the propylene-based elastomer is a copolymer of propylene and C2-C8 olefins.

[0012] Furthermore, the polyolefin elastomer is a copolymer of propylene and one or more of ethylene, isobutylene, 1-butene, 1-hexene, 1-octene, 2-methyl-1-butene, 2-methyl-2-butene, 3-methyl-1-butene, 1-pentene, 1-heptene, and 4-methyl-1-pentene.

[0013] Preferably, the polyolefin elastomer is a copolymer of propylene and ethylene, and the ethylene content is not less than 5 wt%.

[0014] The polyolefin elastomer is selected from ExxonMobil Chemical's Vistamaxx 8880 (viscosity of 1200 mPa·s, elongation at break of 1237%, Shore hardness of 53C, and ethylene content of 6 wt%); ExxonMobil Chemical's Vistamaxx 8380 (viscosity of 7570 mPa·s, elongation of 960%, and ethylene content of 12 wt%).

[0015] In the present invention, the viscosity of the polyolefin elastomer is the viscosity tested at 190°C.

[0016] According to some implementation aspects of the present invention, the melt flow rate of the polypropylene is 1000 to 4000 g / 10 min.

[0017] In some embodiments, the polypropylene is prepared by degradation of homopolypropylene using a peroxide initiator.

[0018] In some embodiments, the homopolypropylene has a melt flow rate of 2 to 50 g / 10 min (ASTM 1238) at 230° C. and 2.16 kg, and the peroxide is a combination of one or more of 1,3-bis(tert-butylperoxyisopropyl)benzene (BIBP) and diisopropylbenzene peroxide (DCP).

[0019] The homopolymer polypropylene is selected from T30S (melt flow rate is 3g / 10min) and Z03S (melt flow rate is 25g / 10min) produced by Maoming Petrochemical.

[0020] In some specific embodiments, the polypropylene is prepared by stirring and degrading dried homopolypropylene, a peroxide initiator, and a polymerization inhibitor at a temperature of 50-70° C., and then melt-blending and granulating them in a twin-screw extruder.

[0021] The polymerization inhibitor is a common polymerization inhibitor, such as hydroquinone.

[0022] According to some embodiments of the present invention, the first polyolefin elastomer layer and the second polyolefin elastomer layer have the same or different raw material formulations, and the first polyolefin elastomer layer and the second polyolefin elastomer layer have substantially the same layer thickness ratio.

[0023] According to some implementation aspects of the present invention, the raw material formulas of the first polyolefin elastomer layer and the second polyolefin elastomer layer further independently include fillers, and the mass ratio of the polyolefin elastomer to the filler is 1:0.1-0.3.

[0024] In some specific embodiments, the filler is one or a combination of calcium carbonate, titanium dioxide, and kaolin.

[0025] In some specific embodiments, the raw material formulas of the first polyolefin elastomer layer and the second polyolefin elastomer layer further independently include masterbatches, which are titanium dioxide masterbatches and antioxidant masterbatches, or a combination of several of them.

[0026] In some specific embodiments, the raw material formulas of the first polyolefin elastomer layer and the second polyolefin elastomer layer respectively include the following components:

[0027] In some specific embodiments, the reinforcement layer is a glass fiber mat reinforcement layer with a gram weight of 35 to 50 g / m 2 .

[0028] In some specific embodiments, the polyolefin waterproof membrane further includes an adhesive layer and a release layer sequentially laminated on the first polyolefin elastomer layer.

[0029] Furthermore, the adhesive layer is a styrene-isoprene-styrene block copolymer-based hot-melt pressure-sensitive adhesive layer; and the anti-sticking layer is an anti-sticking particle layer.

[0030] The second technical solution adopted by the present invention is: a method for preparing the above-mentioned polyolefin waterproof membrane, comprising melt-extruding the raw material of the first polyolefin elastomer layer and hot-pressing and compounding it with the reinforcement layer, cooling and shaping to obtain a composite sheet, and then melt-extruding the raw material of the second polyolefin elastomer layer and hot-pressing and compounding it with the composite sheet, cooling and shaping to obtain it.

[0031] In some specific embodiments, the raw material of the first polyolefin elastomer layer and the raw material of the second polyolefin elastomer layer are respectively fed into a single-screw extruder, and the screw temperature of each single-screw extruder is 180-200°C and the mold temperature is 190-200°C.

[0032] Due to the application of the above technical solution, the present invention has the following advantages compared with the prior art:

[0033] The main raw materials of the polyolefin elastomer layer of the polyolefin waterproof membrane of the present invention are a combination of low-viscosity polyolefin elastomer and high-melt flow rate polypropylene, which helps to improve the overall processing fluidity of the olefin elastomer layer, so that the polyolefin elastomer layer can fully infiltrate the reinforcing layer during extrusion and compounding, reducing excessive extrusion of the polyolefin elastomer layer during calendering due to insufficient fluidity, resulting in invalid orientation, avoiding the reduction of mechanical properties of the polyolefin waterproof membrane due to excessive extrusion, and ensuring that the prepared polyolefin waterproof membrane has good mechanical properties while having high dimensional stability. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] FIG1 is a schematic structural diagram of a polyolefin waterproof membrane according to Example 1;

[0035] FIG2 is a process flow chart for preparing a reinforced TPO sheet in Example 1;

[0036] In Figures 1 and 2: 1. First polyolefin elastomer layer; 2. Reinforcement layer; 3. Second polyolefin elastomer layer; 4. Hot-melt pressure-sensitive adhesive layer; 5. Anti-sticking layer; 6. First single-screw extruder; 7. Second single-screw extruder; 8. First calendering composite roller group; 9. First cooling roller group; 10. Second calendering composite roller group; 11. Second cooling roller group.

[0037] FIG3 is a comparison diagram of the polyolefin waterproof membranes of Example 1 and Comparative Example 5 after being exposed to sunlight outdoors for several days. DETAILED DESCRIPTION

[0038] The inventors of the present application have conducted in-depth research on the reasons for the decline in mechanical properties of polyolefin waterproof membranes reinforced with glass fiber mats through a large number of experiments. They found that if polyolefin elastomers with a conventional low melt flow rate and polypropylene with a conventional melt flow rate are used, the tensile strength and elongation at break of the waterproof membrane after glass fiber mat reinforcement are greatly reduced. The reason is that when compounding the glass fiber mat, the molten material of the polyolefin elastomer layer needs to be extruded. In the molten state of the polyolefin elastomer, if its own fluidity is low, the glass fiber will be embedded in the crystallization process of the polyolefin elastomer, causing excessive extrusion. The polyolefin elastomer is not subjected to normal crystallization orientation, resulting in a significant reduction in the transverse tensile strength and longitudinal elongation at break, affecting the overall performance of the waterproof membrane.

[0039] In order to change this phenomenon, the inventors of the present application adopted a combination of high melt flow rate polypropylene and low viscosity polyolefin elastomer in a certain mass ratio, that is, after being extruded from the mold, it still has high fluidity and can quickly infiltrate and spread on the surface of the glass fiber mat, avoiding unnecessary extrusion, thereby maintaining good crystal orientation of the polyolefin elastomer and avoiding a significant decrease in the mechanical properties of the polyolefin waterproof membrane. The obtained polyolefin waterproof membrane not only retains the high dimensional stability of the glass fiber mat reinforced polyolefin waterproof membrane, but also has good mechanical properties.

[0040] The technical solutions of the present invention are described in detail below in conjunction with specific embodiments so that those skilled in the art can better understand and implement the technical solutions of the present invention, but the present invention is not limited to the scope of the examples.

[0041] Example 1

[0042] The polyolefin waterproof roll with high dimensional stability provided in this embodiment, as shown in FIG1 , comprises a first polyolefin elastomer layer 1, a reinforcing layer 2, a second polyolefin elastomer layer 3, a hot melt pressure sensitive adhesive layer 4 and a release layer 5 stacked in sequence, wherein the first polyolefin elastomer layer 1 and the second polyolefin elastomer layer 3 adopt the same formulation; the reinforcing layer 2 has a gram weight of 45 g / m 2 The glass fiber felt reinforcement layer was purchased from Changzhou Wujin Lantian Glass Fiber Material Factory.

[0043] In this example, the raw material formula of the first polyolefin elastomer layer 1 is shown in Table 1, wherein the polyolefin elastomer is Vistamaxx 8880 from ExxonMobil Corporation, with a tensile strength of 6.2 MPa, an elongation at break of 1237%, and a viscosity of 1200 mPa·s; and the calcium carbonate is Omyacarb 2T from Omya Corporation.

[0044] In this example, polypropylene was obtained by the following method: 100 parts of fully dried homopolymer polypropylene T30S, 0.3 parts of initiator BIBP, and 0.1 parts of inhibitor were stirred at a low speed for 30 minutes in a stirred tank maintained at a constant temperature of 60°C to obtain a mixture that fully absorbed the initiator and inhibitor. The mixture was then added to a twin-screw extruder for thorough melt blending, extruded into granules, and obtained polypropylene particles with a melt flow rate of approximately 1500 g / 10 min. The particles were then dried and set aside.

[0045] In this example, titanium dioxide masterbatch is obtained by the following method: titanium dioxide, polyolefin elastomer, and polypropylene are added into a twin-screw extruder in a mass ratio of 2:1:1, melt-extruded, and underwater stranded and pelletized to obtain titanium dioxide masterbatch, wherein titanium dioxide is rutile titanium dioxide R105 from Chemours, the screw aspect ratio is 48:1, the screw temperature is 180°C, and the pelletizing speed is 9 m / min.

[0046] In this example, the antioxidant masterbatch is obtained by the following method: adding the antioxidant, polyolefin elastomer, and polypropylene in a mass ratio of 1:1:1 into a twin-screw extruder, melt-extruding, underwater stranding and pelletizing to obtain the antioxidant masterbatch, wherein the antioxidant is BASF's Irganox 1010, the screw aspect ratio is 48:1, the screw temperature is 180°C, and the pelletizing speed is 9 m / min.

[0047] The polyolefin waterproof membrane with high dimensional stability in this example is prepared by the following method:

[0048] (1) The first polyolefin elastomer layer 1 and the second polyolefin elastomer layer 3 are dry-blended in a mixer according to the formulations in Table 1 to obtain a mixture. The dry-blending temperature is controlled within 40°C. If the temperature is higher than this, the material may easily stick to the stirring paddle and the inner wall of the mixer. The mixtures of the first and second polyolefin elastomer layers are then fed into a single-screw extruder and composited with the reinforcement layer 2 with reference to the process in FIG2 . Specifically, the formula mixture of the first polyolefin elastomer layer 1 is melt-extruded in the first single-screw extruder 6, and is hot-pressed and compounded with the glass fiber felt reinforcement layer 2 in a molten state through the first calendering composite roller group 8, and then is cooled and shaped by the first cooling roller group 9 to obtain a composite sheet; the formula mixture of the second polyolefin elastomer layer 3 is then melt-extruded in the second single-screw extruder 7, and is hot-pressed and compounded with the composite sheet in a molten state through the second calendering composite roller group 10, and then is cooled and shaped by the second cooling roller group 11, and is wound to obtain a reinforced TPO sheet, wherein the total thickness is controlled to be 1.2 mm, and the melt extrusion thickness of the first polyolefin elastomer layer 1 and the second polyolefin elastomer layer 3 is controlled to be consistent; the screw temperature of the first twin-screw extruder 6 and the second twin-screw extruder 7 are 190°C, and the mold temperature is 200°C; the compound temperature of the first calendering composite roller group 8 and the second calendering composite roller group 10 are 60°C; the cooling temperature of the first cooling roller group 9 and the second cooling roller group 11 are 25°C, respectively.

[0049] (2) According to the combination of SIS rubber, cyclohexane oil and hydrogenated C5 petroleum resin in a mass ratio of 25:25:50, and then 0.3% and 0.5% of the total weight of the hot melt pressure sensitive adhesive respectively, the mixture was mixed by a twin-screw extruder and extrusion coated on one side of the reinforced TPO sheet to form a hot melt pressure sensitive adhesive layer with a thickness of 0.25 mm, wherein the extruder feeding speed was 20 RPM, the screw speed was 110 RPM, and the extruder temperature was set as follows: room temperature in the feeding section, 90-100°C in the compression section, 120-140°C in the metering section, and the coating temperature was 140-150°C.

[0050] (3) Modified sand particles are evenly sprinkled on the hot melt pressure sensitive adhesive layer, and an anti-sticking layer is formed by rolling with a rubber roller to finally obtain a polyolefin waterproof membrane.

[0051] Example 2

[0052] The high dimensional stability polyolefin waterproof membrane of this embodiment has a structure similar to that of Example 1, except that the raw material formulas of the first polyolefin elastomer layer and the second polyolefin elastomer layer are as shown in Table 1.

[0053] Example 3

[0054] The high dimensional stability polyolefin waterproof membrane of this embodiment has a structure similar to that of Example 1, except that the raw material formulas of the first polyolefin elastomer layer and the second polyolefin elastomer layer are as shown in Table 1.

[0055] Example 4

[0056] The high dimensional stability polyolefin waterproof membrane of this embodiment has a structure similar to that of Example 1, except that the raw material formulas of the first polyolefin elastomer layer and the second polyolefin elastomer layer are as shown in Table 1.

[0057] In this case, the polyolefin elastomer is Vistamaxx 8380;

[0058] Polypropylene particles with a melt flow rate of 1000 g / 10 min were prepared using T30S.

[0059] Example 5

[0060] The high dimensional stability polyolefin waterproof membrane of this embodiment has a structure similar to that of Example 1, except that the raw material formulas of the first polyolefin elastomer layer and the second polyolefin elastomer layer are as shown in Table 1.

[0061] In this example, polypropylene Z30S is used to prepare polypropylene particles with a melt flow rate of 4000 g / 10 min.

[0062] Comparative Example 1

[0063] The structure of the polyolefin waterproof membrane of this comparative example is basically the same as that of Example 1, except that the raw material formulas of the first polyolefin elastomer layer and the second polyolefin elastomer layer are as shown in Table 1.

[0064] Comparative Example 2

[0065] The structure of the polyolefin waterproof membrane of this comparative example is basically the same as that of Example 1, except that the raw material formulas of the first polyolefin elastomer layer and the second polyolefin elastomer layer are as shown in Table 1.

[0066] Comparative Example 3

[0067] The structure of the polyolefin waterproof membrane of this comparative example is basically the same as that of Example 1, except that the polypropylene in the first polyolefin elastomer layer and the second polyolefin elastomer layer is replaced by T30S.

[0068] Comparative Example 4

[0069] The structure of the polyolefin waterproof membrane of this comparative example is basically the same as that of Example 1, except that the polyolefin elastomer and polypropylene in the first polyolefin elastomer layer and the second polyolefin elastomer layer are different from those in Example 1.

[0070] In this example, the polyolefin elastomer used is Vistamaxx 6102 from ExxonMobil, with a tensile strength of >7.6 MPa, an elongation at break >800%, and a melt flow rate (MFR 230°C, 2.16 kg) of 3 g / 10 min. However, its viscosity is too high, far exceeding 8000 mPa·s, and cannot be measured.

[0071] Polypropylene uses T30S.

[0072] Comparative Example 5

[0073] The polyolefin waterproof membrane of this comparative example does not contain a glass fiber felt reinforcement layer in its structure, and the rest is the same as in Example 1.

[0074] Table 1 Raw material formula of the first polyolefin elastomer layer and the second polyolefin elastomer layer in Examples 1 to 5 and Comparative Examples 1 to 2 (parts by weight)

[0075] The polyolefin waterproof membranes of Examples 1 to 5 and Comparative Examples 1 to 5 were tested in accordance with T / CBMF 43-2019. The test results are shown in Tables 2 and 3.

[0076] Table 2 Performance test results of polyolefin waterproof membranes of Examples 1 to 5

[0077] Table 3 Performance test results of polyolefin waterproof membranes of Comparative Examples 1 to 5

[0078] It can be seen from the above that the dimensional change rate of the polyolefin waterproof membrane reinforced with glass fiber felt is significantly lower, and the polyolefin waterproof membranes of Example 1 and Comparative Example 5 were respectively subjected to outdoor exposure tests (exposure dates were June 26, 2023 to July 13, 2023). The results are shown in Figure 3. The polyolefin waterproof membrane of Comparative Example 5 has serious bulging and warping on the surface; while the surface of the polyolefin waterproof membrane of Example 1 is still in contact with the concrete base after many days of outdoor exposure, which helps to reduce the risks of water seepage and leakage caused by the release of internal stress caused by temperature during construction, and greatly improves the stability of the construction quality of the waterproof membrane.

[0079] Comparison of Example 1 and Comparative Examples 1-2 shows that the amounts of polyolefin elastomer and polypropylene must be stabilized within a certain range. Exceeding this range does not significantly improve the tensile strength and elongation at break, but instead affects the puncture resistance and surface hardness. Increasing the mass ratio of polypropylene helps to improve the puncture resistance, but significantly increases the surface Shore hardness and decreases the softness, affecting the convenience during construction.

[0080] Comparing Example 1 with Comparative Examples 3-4, it can be seen that the mechanical properties (such as tensile strength and elongation at break) of the polyolefin waterproofing membrane prepared in Comparative Example 4, which uses a conventional polyolefin elastomer with a low melt flow rate and polypropylene with a conventional melt flow rate, show a significant decrease. Furthermore, even in Comparative Example 3, which uses a low-viscosity polyolefin elastomer and polypropylene with a conventional melt flow rate, the mechanical properties of the polyolefin waterproofing membrane still show a significant decrease.

[0081] The above embodiments are intended only to illustrate the technical concepts and features of the present invention. Their purpose is to enable those skilled in the art to understand the contents of the present invention and implement them accordingly. They are not intended to limit the scope of protection of the present invention. Any equivalent changes or modifications made in accordance with the spirit of the present invention are intended to be covered by the scope of protection of the present invention.

[0082] The endpoints of the ranges and any values ​​disclosed herein are not limited to the precise ranges or values, and these ranges or values ​​should be understood to include values ​​close to these ranges or values. For numerical ranges, the endpoints of each range, the endpoints of each range and individual point values, and the individual point values ​​can be combined with each other to obtain one or more new numerical ranges, which should be considered to be specifically disclosed herein.

Claims

1. A polyolefin waterproofing coiled material, comprising a first polyolefin elastomer layer, a reinforcing layer and a second polyolefin elastomer layer stacked in sequence, characterized in that: The raw material formulas of the first polyolefin elastomer layer and the second polyolefin elastomer layer independently include polyolefin elastomer and polypropylene, the sum of the mass of the polyolefin elastomer and the polypropylene accounts for more than 75% of the total mass of the raw materials of the first polyolefin elastomer layer or the second polyolefin elastomer layer, the mass ratio of the polyolefin elastomer to the polypropylene is 1:0.3-0.7, wherein the viscosity of the polyolefin elastomer is less than 8000 mPa·s; the melt flow rate of the polypropylene at 230°C and 2.16 kg is more than 1000 g / 10min; The viscosity of the polyolefin elastomer is the viscosity tested at 190°C; The reinforcement layer is a glass fiber felt reinforcement layer.

2. A polyolefin waterproofing roll, comprising a first polyolefin elastomer layer, a reinforcing layer and a second polyolefin elastomer layer stacked in sequence, characterized in that: The raw material formulas of the first polyolefin elastomer layer and the second polyolefin elastomer layer independently include polyolefin elastomer and polypropylene, the sum of the masses of the polyolefin elastomer and the polypropylene accounts for more than 75% of the total mass of the raw materials of the first polyolefin elastomer layer or the second polyolefin elastomer layer, and the mass ratio of the polyolefin elastomer to the polypropylene is 1:0.3-0.7, wherein the viscosity of the polyolefin elastomer is less than 8000 mPa·s; and the melt flow rate of the polypropylene at 230°C and 2.16 kg is more than 1000 g / 10 min.

3. The polyolefin waterproofing membrane according to claim 2, characterized in that: The viscosity of the polyolefin elastomer is 500 to 8000 mPa·s; and / or the elongation at break of the polyolefin elastomer is greater than 800%.

4. The polyolefin waterproofing membrane according to claim 2, characterized in that: The polyolefin elastomer is selected from propylene-based elastomers, and the propylene-based elastomer is a copolymer of propylene and C2-C8 olefins.

5. The polyolefin waterproofing membrane according to claim 4, characterized in that: The polyolefin elastomer is a copolymer of propylene and one or more of ethylene, isobutylene, 1-butene, 1-hexene, 1-octene, 2-methyl-1-butene, 2-methyl-2-butene, 3-methyl-1-butene, 1-pentene, 1-heptene, and 4-methyl-1-pentene.

6. The polyolefin waterproofing membrane according to claim 5, characterized in that: The polyolefin elastomer is a copolymer of propylene and ethylene, and the ethylene content is not less than 5wt%.

7. The polyolefin waterproofing membrane according to claim 2, characterized in that: The melt flow rate of the polypropylene is 1000-4000 g / 10 min.

8. The polyolefin waterproofing membrane according to claim 7, characterized in that: The polypropylene is prepared by degradation of homopolypropylene by using a peroxide initiator.

9. The polyolefin waterproofing membrane according to claim 8, characterized in that: The homopolypropylene has a melt flow rate of 2-50 g / 10 min at 230° C. and 2.16 kg; and / or the peroxide is a combination of one or more of 1,3-bis(tert-butylperoxyisopropyl)benzene and diisopropylbenzene peroxide.

10. The polyolefin waterproofing membrane according to claim 8, characterized in that: The polypropylene is prepared by mixing and degrading dried homopolymerized polypropylene, a peroxide initiator and a polymerization inhibitor at a temperature of 50-70° C., and then placing the mixture in a twin-screw extruder for melt blending and granulation.

11. The polyolefin waterproofing membrane according to claim 2, characterized in that: The first polyolefin elastomer layer and the second polyolefin elastomer layer have the same or different raw material formulations.

12. The polyolefin waterproofing membrane according to any one of claims 2 to 11, characterized in that: The raw material formulas of the first polyolefin elastomer layer and the second polyolefin elastomer layer further independently include fillers, and the mass ratio of the polyolefin elastomer to the filler is 1:0.1-0.

3.

13. The polyolefin waterproofing membrane according to claim 12, characterized in that: The filler is one or a combination of calcium carbonate, titanium dioxide, and kaolin; and / or the raw material formula of the first polyolefin elastomer layer and the second polyolefin elastomer layer also independently includes masterbatch, and the masterbatch is one or a combination of titanium dioxide masterbatch and antioxidant masterbatch.

14. The polyolefin waterproofing membrane according to claim 12, characterized in that: The raw material formulas of the first polyolefin elastomer layer and the second polyolefin elastomer layer respectively include the following components:

15. The polyolefin waterproofing membrane according to claim 2, characterized in that: The reinforcing layer is a glass fiber felt reinforcing layer, and its gram weight is 35-50g / m 2 .

16. The polyolefin waterproofing membrane according to claim 2, characterized in that: The polyolefin waterproof membrane further includes an adhesive layer and a release layer sequentially laminated on the first polyolefin elastomer layer.

17. The polyolefin waterproofing membrane according to claim 16, characterized in that: The adhesive layer is a styrene-isoprene-styrene block copolymer-based hot-melt pressure-sensitive adhesive layer; the anti-sticking layer is an anti-sticking particle layer.

18. A method for preparing the polyolefin waterproofing membrane according to any one of claims 2 to 16, characterized in that: The preparation method comprises the steps of melt-extruding the raw material of the first polyolefin elastomer layer, hot-pressing and compounding it with the reinforcing layer, cooling and shaping to obtain a composite sheet, and then melt-extruding the raw material of the second polyolefin elastomer layer, hot-pressing and compounding it with the composite sheet, cooling and shaping to obtain the composite sheet.

19. The method for preparing a polyolefin waterproofing membrane according to claim 18, characterized in that: The raw material of the first polyolefin elastomer layer and the raw material of the second polyolefin elastomer layer are respectively fed into single-screw extruders. The screw temperature of each single-screw extruder is 180-200°C and the die temperature is 190-200°C.

Images