Anti-sagging polyurethane waterproof coating with high efficiency fusion with asphalt roll material, preparation method and application thereof

Abstract

The present application relates to a kind of with asphalt coiled material high-efficiency fusion anti sagging polyurethane waterproof coating and its preparation method and application.The coating includes the following components: maleic anhydride modified polyurethane, silane modified powder, maleic anhydride modified gum and solvent;Maleic anhydride modified polyurethane is obtained by the reaction of raw materials including polyol, maleic anhydride, isocyanate and catalyst;Silane modified powder is obtained by the reaction of raw materials including silane coupling agent and powder;Gum is selected from the combination of one or more of petroleum resin, asphalt, rosin resin, terpene resin, butyl benzene glue and butyl glue;Maleic anhydride modified gum is obtained by the reaction of raw materials including maleic anhydride, gum, initiator and plasticizer.The compatibility and bonding performance between the polyurethane waterproof coating and asphalt coiled material are good, and the two are not easy to delaminate and peel off, and the waterproof coating can be used as the primer of concrete substrate, with high adhesion strength to substrate, while excellent sagging resistance.

Description

Technical Field

[0001] This invention relates to an anti-sagging polyurethane waterproof coating that can be efficiently integrated with asphalt rolls, its preparation method, and its application. Background Technology

[0002] When traditional asphalt roofing membranes are used in roofing, underground structures, and bridges, waterproofing treatment is required, typically by coating their surface with polyurethane waterproofing coatings. However, traditional asphalt roofing membranes are non-polar materials, while polyurethane waterproofing coatings are highly polar. This significant difference in polarity often leads to insufficient interfacial adhesion. Prolonged exposure to extreme environments or delamination of the asphalt roofing membrane can cause delamination and peeling, affecting the overall waterproofing effect. Conventional polyurethane is produced using polyether and isocyanate as raw materials, often with the addition of plasticizers, powder materials, additives, and solvents. Its high polarity results in poor adhesion to non-polar self-adhesive asphalt roofing membranes, particularly in systems like sidewalls and sloping roofs, where poor bonding easily leads to interfacial damage and loss of adhesion, causing the membrane to detach during backfilling. Furthermore, traditional polyurethane waterproofing coatings do not offer sufficient resistance to sag. Summary of the Invention

[0003] The technical problem to be solved by this invention is to address the shortcomings and deficiencies of existing technologies by providing an anti-sagging polyurethane waterproof coating that can be efficiently integrated with asphalt roofing membranes. This polyurethane waterproof coating exhibits good compatibility and adhesion with asphalt roofing membranes, preventing delamination and peeling. Furthermore, this waterproof coating can be used as a primer for substrates such as concrete, demonstrating high adhesion strength and excellent anti-sagging properties.

[0004] An anti-sagging polyurethane waterproof coating comprises the following components: maleic anhydride-modified polyurethane, silane-modified powder, maleic anhydride-modified adhesive, and solvent; the maleic anhydride-modified polyurethane is obtained by reacting raw materials including polyol, maleic anhydride, isocyanate, and catalyst; the silane-modified powder is obtained by reacting raw materials including silane coupling agent and powder; the adhesive is selected from one or more combinations of petroleum resin, asphalt, rosin resin, terpene resin, styrene-butadiene rubber, and butyl rubber; the maleic anhydride-modified adhesive is obtained by reacting raw materials including maleic anhydride, adhesive, initiator, and plasticizer.

[0005] In this invention, the anti-sagging polyurethane waterproof coating refers to a polyurethane waterproof coating that can pass the 1mm non-flow test.

[0006] Traditional polyurethane waterproof coatings are highly polar, while asphalt waterproof membranes are non-polar. This difference in polarity results in insufficient adhesion when they are bonded together, making it easy for the polyurethane waterproof coating to peel off from the membrane. The inventors of this application have discovered through research that by adding maleic anhydride-modified polyurethane, silane-modified powder, and maleic anhydride-modified adhesive to the polyurethane waterproof coating, the matrix adhesive in the maleic anhydride-modified adhesive is non-polar, which facilitates adhesion with the non-polar asphalt waterproof membrane. Furthermore, the adhesive itself typically acts as a tackifier, increasing bond strength. The silane coupling agent component in the silane-modified powder improves the compatibility between the asphalt waterproof membrane and the polyurethane, as well as the compatibility between the powder and the polyurethane matrix. Moreover, the maleic anhydride-modified polyurethane, maleic anhydride-modified adhesive, and silane-modified powder react further after mixing, further improving the polarity of the polyurethane chain segments. This application utilizes a compounding process involving maleic anhydride-modified polyurethane, maleic anhydride-modified adhesive, and silane-modified powder to achieve full microphase fusion of polar and non-polar materials. This improves the sustained adhesion between traditional polyurethane waterproof coatings and asphalt membranes, as well as their adhesion to substrates such as concrete, making them less prone to peeling.

[0007] In some embodiments, the mass ratio of the maleic anhydride-modified polyurethane, silane-modified powder, maleic anhydride-modified adhesive, and solvent is 20-40:30-60:15-35:5-10.

[0008] In some embodiments, the polyol is selected from polyether polyols or polyester polyols.

[0009] The polyether polyol can be one or more of the following: 2000d, 1000d, 3050d, and 330Nd from Dongda Chemical Co., Ltd.

[0010] In some embodiments, the isocyanate is selected from one or more combinations of toluene diisocyanate (TDI), diphenylmethane diisocyanate (MDI), hexamethylene diisocyanate (HDI), isophorone diisocyanate (IPDI), and 4,4'-dicyclohexylmethane diisocyanate (HMDI).

[0011] In some embodiments, the silane coupling agent is selected from one or more combinations of WD50, KH550, KH560, KH570 and propyltriethoxysilane (IPTS).

[0012] In some embodiments, the catalyst is selected from one or more combinations of organotin NEOSTANN U-303, butyltin dilaurate, stannous octoate, zinc isooctanoate, bismuth isooctanoate, bismuth neodecanoate, and zinc neodecanoate. Organotin NEOSTANN U-303 is manufactured by Nitto Chemical Corporation and is composed of the reaction product of tetraethyl silicate and bis(acetyloxy)dibutyltinane.

[0013] In some embodiments, the initiator is selected from azo initiators or organic peroxide initiators. An example of an organic peroxide initiator is dicumyl peroxide.

[0014] In some embodiments, the powder is selected from one or more combinations of heavy calcium carbonate, talc, kaolin, and light calcium carbonate.

[0015] In some embodiments, the plasticizer is selected from one or more combinations of chlorinated paraffin, diisononyl phthalate (DINP), methyl palmitate, diisodecyl phthalate (DIDP), and diisononyl cyclohexane 1,2-dicarboxylate (DINCH).

[0016] In some embodiments, the plasticizer is selected from one or more combinations of chlorinated paraffin, diisononyl phthalate (DINP), methyl palmitate, diisodecyl phthalate (DIDP), and diisononyl cyclohexane-1,2-dicarboxylate (DINCH). The addition of a plasticizer can improve the flexibility of the polyurethane waterproof coating.

[0017] In some embodiments, the mass ratio of the polyol, maleic anhydride, isocyanate and catalyst in the raw materials of the maleic anhydride-modified polyurethane is 60-70:2-6:22-40:0.01-0.05.

[0018] In some embodiments, the mass ratio of the silane coupling agent to the powder in the raw materials of the silane-modified powder is 0.3-1:99-100.

[0019] In some embodiments, the mass ratio of maleic anhydride, gum, and initiator in the raw material of the maleic anhydride modified gum is 15-25:75-85:0.05-0.15.

[0020] In some embodiments, the anti-sagging polyurethane waterproof coating also includes a catalyst.

[0021] In some embodiments, the mass ratio of the maleic anhydride-modified polyurethane to the catalyst is 20-40:0.05-0.1.

[0022] In some embodiments, the anti-sagging polyurethane waterproof coating further includes a dispersant, a defoamer, a dehydrating agent, and a catalyst.

[0023] In some embodiments, the mass ratio of the maleic anhydride-modified polyurethane, silane-modified powder, maleic anhydride-modified adhesive, solvent, dispersant, defoamer, dehydrating agent, and catalyst is 20-40:30-60:15-35:5-10:0.1-0.3:0.1-0.3:1-3:0.05-0.1.

[0024] In some embodiments, the dispersant is selected from one or both of F108 coating dispersant and 9250 dispersant.

[0025] In some embodiments, the defoamer is selected from one or more combinations of BYK-066N defoamer, 5500 defoamer, and silicone defoamer.

[0026] In some embodiments, the dehydrating agent is selected from vinyltrimethoxysilane A-171.

[0027] In some embodiments, the catalyst is selected from one or more combinations of organotin NEOSTANN U-303, butyltin dilaurate, stannous octoate, zinc isooctanoate, bismuth isooctanoate, bismuth neodecanoate, and zinc neodecanoate.

[0028] The present invention further provides a method for preparing the above-mentioned anti-sagging polyurethane waterproof coating, the method comprising the step of mixing and dispersing the maleic anhydride modified polyurethane, silane modified powder, maleic anhydride modified adhesive and other raw materials to obtain the anti-sagging polyurethane waterproof coating.

[0029] In some embodiments, the mixing and dispersion can be carried out in a twin-screw extruder. In the waterproofing field, polyurethane waterproof coatings have high solid content requirements; the solid content of single-component polyurethane waterproof coatings is typically above 85%. Twin-screw extruders facilitate smooth mixing, dispersion, and discharge.

[0030] In some embodiments, the method further includes the step of preparing the maleic anhydride-modified polyurethane: adding the polyol to a reaction vessel, heating to dehydrate, then adding maleic anhydride and a catalyst, and adding isocyanate dropwise to react, testing the NCO content of the system, and when the NCO content of the system is less than 6.1%, the reaction is complete, and the maleic anhydride-modified polyurethane is obtained.

[0031] In some embodiments, the dripping time is 10-40 minutes.

[0032] In some implementations, the temperature is heated to 80-130°C.

[0033] In some implementations, the water content is reduced to less than 0.05% by mass.

[0034] In some embodiments, the method further includes the step of preparing the silane-modified powder: adding the powder to a dryer, then adding a solution of silane coupling agent to react, and dehydrating to obtain the silane-modified powder.

[0035] In some embodiments, the dripping time is 10-40 minutes.

[0036] In some implementations, the temperature is heated to 80-130°C.

[0037] In some implementations, the water content is reduced to less than 0.05% by mass.

[0038] In some embodiments, the method further includes the step of preparing the maleic anhydride-modified gum: adding the gum and plasticizer to a reaction vessel, heating and then adding maleic anhydride and initiator to carry out the reaction, thereby obtaining the maleic anhydride-modified gum.

[0039] The present invention further provides the use of the aforementioned anti-sagging polyurethane waterproof coating for bonding asphalt rolls.

[0040] This invention further provides the use of the aforementioned anti-sagging polyurethane coating as a primer for concrete substrates. The anti-sagging polyurethane coating of this application can also be used as a primer, and it has very good adhesion to concrete substrates, even damp surfaces. The bond strength between the coating formed by the anti-sagging polyurethane waterproof coating and the concrete substrate is higher than 2.0 MPa.

[0041] Furthermore, the aforementioned anti-sagging polyurethane waterproof coating is used to bond asphalt roofing membranes and concrete substrates.

[0042] The present invention further provides a waterproof laminate comprising a substrate layer, an anti-sagging polyurethane waterproof coating layer, and an asphalt membrane layer, wherein the anti-sagging polyurethane waterproof coating layer is formed by the aforementioned anti-sagging polyurethane waterproof coating.

[0043] Preferably, the bitumen membrane is selected from SBS waterproof membrane or APP waterproof membrane. These two types of waterproof membranes do not have a release liner and can be directly bonded to an anti-sagging polyurethane waterproof coating.

[0044] Preferably, the bitumen waterproof membrane is selected from wet-laid waterproof membranes or self-adhesive polymer-modified bitumen waterproof membranes. Both types of waterproof membranes have a release liner on their surface. This release liner needs to be removed to expose the adhesive layer before it is bonded to the anti-sagging polyurethane waterproof coating.

[0045] Furthermore, the substrate layer is a building surface.

[0046] Preferably, the building surface is a roof, a garage roof, or a basement side wall.

[0047] Due to the application of the above technical solution, the present invention has the following advantages compared with the prior art:

[0048] This application utilizes a compound of maleic anhydride-modified polyurethane, maleic anhydride-modified adhesive, and silane-modified powder to create a polyurethane with both soft and hard grafting modifications. This significantly enhances the bond strength between traditional polyurethane waterproof coatings and asphalt waterproof membranes, ensuring that traditional polyurethane waterproof coatings maintain excellent waterproofing and sealing properties even in complex and variable environments.

[0049] The anti-sagging polyurethane waterproof coating of this application has excellent continuous adhesion to substrates such as concrete and color steel roofs, and also has very good adhesion to damp substrates. After immersion in water, the bonding strength reaches more than 80%. It can be used for roll-coating composite waterproofing in underground engineering and is suitable for waterproofing applications on various substrates and complex substrates.

[0050] The anti-sagging polyurethane waterproof coating of this application can form a high-strength chemical bond with asphalt membrane and is suitable for long-term exposure.

[0051] The anti-sagging polyurethane waterproof coating of this application solves the problems of poor adhesion, easy peeling, and poor weather resistance between asphalt membrane and polyurethane waterproof coating in the prior art. It can improve the overall durability and sealing performance of the composite waterproof layer and can be widely used in waterproof sealing treatment of roofs, underground structures and bridges. Detailed Implementation

[0052] The technical solutions of the present invention will be described in detail below with reference to 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 described.

[0053] Unless otherwise specified, all raw materials in the following examples were commercially available or prepared using conventional methods in the art. TDI, MDI, HMDI, and IPDI were purchased from Wanhua Chemical; polyether 2000, polyether 1000, 330N, and 3050 were purchased from Shandong Lanxing and Dongda Chemical, respectively; the defoamer was BYK Chemical 066N; the dispersant was 9250; the catalyst was butyltin dilaurate; the dehydrating agent was vinyltrimethoxysilane A-171; and No. 70 asphalt, butyl rubber, and rosin resin were purchased from Sinopec.

[0054] Example 1

[0055] This example provides an anti-sagging polyurethane waterproof coating, the raw material composition (parts by weight) of which is shown in Table 1, and the preparation method is as follows:

[0056] 1) Preparation of maleic anhydride modified polyurethane: Polyether polyol polyether 2000 was added to the reactor and heated to 110℃ for more than 2 hours to dehydrate. The moisture content was tested until it was below 0.05%. Then the reactor was cooled to 80℃, and maleic anhydride and catalyst butyltin dilaurate were added at once. The mixture was stirred for 20 minutes. Then TDI was added dropwise to the reactor within 20 minutes. The mixture was stirred and kept at the temperature for 2 hours. The NCO content was tested by di-n-butylamine titration. When it reached 5.5%, the reaction was considered complete. Stirring was stopped and the material was discharged.

[0057] The mass ratio of polyether polyol, isocyanate TDI, maleic anhydride and catalyst is 65:22:3:0.01.

[0058] 2) Preparation of silane-modified powder: Add powder (heavy calcium carbonate, talc, and kaolin mixed in a 1:2:1 mass ratio) to a vertical nitrogen-fixing powder dryer with baghouse dust collection. While heating and stirring, spray a mixed ethanol solution of coupling agents KH550, KH560, and KH570. The temperature should not exceed 80℃. After stirring, drying, modifying, and dispersing for approximately 1 hour, turn on the nitrogen-fixing equipment and heat to 130℃ for deep moisture processing and drying for 3 hours. Once the moisture content is tested to be below 0.05%, the powder can be discharged to a cooling chamber for later use. Powder material ratio: KH550:KH560:KH570 = 10:0.01:0.02:0.03.

[0059] 3) Preparation of maleic anhydride modified rubber: Add No. 70 asphalt, butyl rubber and plasticizer (a mixture of chlorinated paraffin and DINP) to a kneader, then heat to 90℃, add maleic anhydride and initiator dicumyl peroxide, dehydrate and knead and react under vacuum of -0.1MPa for 2-4 hours until the moisture content is below 0.1%, stir for 30 minutes and discharge.

[0060] The mass ratio of chlorinated paraffin, DINP, No. 70 bitumen, butyl rubber, maleic anhydride and initiator is 10:10:50:25:20:0.1.

[0061] 4) Add the raw materials in Table 1 to a twin-screw extruder, mix, degas, disperse, react, and extrude to obtain an anti-sagging polyurethane waterproof coating.

[0062] Examples 2-5

[0063] This example provides an anti-sagging polyurethane waterproof coating, which is basically the same as Example 1, except that its raw material composition is different from that of Example 1. Its specific composition is shown in Table 1.

[0064] Example 6

[0065] This example provides an anti-sagging polyurethane waterproof coating, which is basically the same as Example 1, except that the type of powder in step 2) is replaced with a mixture of heavy calcium carbonate and talc powder in a mass ratio of 1:1.

[0066] Example 7

[0067] This example provides an anti-sagging polyurethane waterproof coating, which is basically the same as Example 1, except that the butyl rubber in step 3) is replaced with rosin resin.

[0068] Comparative Example 1

[0069] This example provides a polyurethane waterproof coating, which is basically the same as Example 1, except that the powder in step 2) is not modified with silane, that is, no silane coupling agent is added in step 2).

[0070] Comparative Example 2

[0071] This example provides a polyurethane waterproof coating, which is basically the same as Example 1, except that the polyurethane in step 1) is not modified with maleic anhydride, that is, maleic anhydride is not added in step 1).

[0072] Comparative Example 3

[0073] This example provides a polyurethane waterproof coating, which is basically the same as Example 1, except that the adhesive in step 3) is not modified with maleic anhydride, that is, maleic anhydride and initiator are not added in step 3).

[0074] Table 1. Raw material composition of anti-sagging polyurethane waterproof coatings in each embodiment.

[0075]

[0076]

[0077] Performance tests were conducted on the polyurethane waterproof coatings of Examples 1-7 and Comparative Examples 1-3. The test methods were in accordance with the standards GB / T19250-2013 Polyurethane Waterproof Coatings and Q / 320584PBT046 Polyurethane Waterproof Coatings for Adhesive Bituminous Membrane Rolls. The test results are shown in Table 2.

[0078] Table 2 Performance results of polyurethane waterproof coatings in each example and comparative example

[0079]

[0080] The peel strength of the asphalt roofing membrane may be slightly improved after immersion and heat treatment compared to the untreated membrane. This is because the water pressure during immersion and the heat melting effect during heat treatment promote better adhesion between the two materials, thus increasing the peel strength.

[0081] As can be seen from Table 2, this application significantly enhances the peel strength between traditional anti-sagging polyurethane waterproof coatings and asphalt waterproof membranes by compounding maleic anhydride-modified polyurethane, maleic anhydride-modified adhesive and silane-modified powder, and also increases its bonding strength with concrete substrates.

[0082] The above embodiments are only for illustrating the technical concept and features of the present invention, and are intended to enable those skilled in the art to understand the content of the present invention and implement it accordingly. They are not intended to limit the scope of protection of the present invention. All equivalent changes or modifications made in accordance with the spirit and essence of the present invention should be covered within the scope of protection of the present invention.

[0083] The endpoints and any values ​​of the ranges 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 endpoint values ​​of the various ranges, the endpoint values ​​of the various ranges and individual point values, and individual point values ​​can be combined with each other to obtain one or more new numerical ranges, which should be considered as specifically disclosed herein.

Claims

1. A sagging-resistant polyurethane waterproof coating, characterized in that: The anti-sagging polyurethane waterproof coating comprises the following components: maleic anhydride-modified polyurethane, silane-modified powder, maleic anhydride-modified adhesive, and solvent; the maleic anhydride-modified polyurethane is obtained by reacting raw materials including polyol, maleic anhydride, isocyanate, and catalyst; the silane-modified powder is obtained by reacting raw materials including silane coupling agent and powder; the adhesive is selected from one or more combinations of petroleum resin, asphalt, rosin resin, terpene resin, styrene-butadiene rubber, and butyl rubber; the maleic anhydride-modified adhesive is obtained by reacting raw materials including maleic anhydride, adhesive, initiator, and plasticizer. The mass ratio of the maleic anhydride-modified polyurethane, silane-modified powder, maleic anhydride-modified adhesive, and solvent is 20-40:30-60:15-35:5-10. In the raw materials of the maleic anhydride-modified polyurethane, the mass ratio of the polyol, maleic anhydride, isocyanate and catalyst is 60-70:2-6:22-40:0.01-0.

05. In the raw materials of the silane-modified powder, the mass ratio of the silane coupling agent to the powder is 0.3-1:99-100; In the raw materials of the maleic anhydride modified gum, the mass ratio of maleic anhydride, gum, initiator and plasticizer is 15-25:75-85:0.05-0.15:10-20.

2. The anti-sagging polyurethane waterproof coating according to claim 1, characterized in that: The polyol is selected from polyether polyols or polyester polyols; and / or, the isocyanate is selected from one or more combinations of toluene diisocyanate (TDI), diphenylmethane diisocyanate (MDI), hexamethylene diisocyanate (HDI), isophorone diisocyanate (IPDI), and 4,4'-dicyclohexylmethane diisocyanate (HMDI).

3. The anti-sagging polyurethane waterproof coating according to claim 1, characterized in that: The silane coupling agent is selected from one or more combinations of WD50, KH550, KH560, KH570 and propyltriethoxysilane (IPTS); and / or, the catalyst is selected from one or more combinations of organotin NEOSTANN U-303, butyltin dilaurate, stannous octoate, zinc isooctanoate, bismuth isooctanoate, bismuth neodecanoate, and zinc neodecanoate; and / or, the initiator is selected from azo initiators or organic peroxide initiators; and / or, the powder is selected from one or more combinations of heavy calcium carbonate, talc, kaolin, and light calcium carbonate.

4. The anti-sagging polyurethane waterproof coating according to claim 1, characterized in that: The solvent is selected from one or more combinations of aromatic hydrocarbons, dimethyl carbonate and butyl acetate; and / or, the plasticizer is selected from one or more combinations of chlorinated paraffin, diisononyl phthalate (DINP), methyl palm oil chloride, diisodecyl phthalate (DIDP), and diisononyl cyclohexane 1,2-dicarboxylate (DINCH).

5. The anti-sagging polyurethane waterproof coating according to claim 1, characterized in that: The anti-sagging polyurethane waterproof coating also includes dispersants, defoamers, dehydrating agents, and catalysts.

6. The anti-sagging polyurethane waterproof coating according to claim 5, characterized in that: The mass ratio of the maleic anhydride modified polyurethane, silane modified powder, maleic anhydride modified adhesive, solvent, dispersant, defoamer, dehydrating agent and catalyst is 20-40:30-60:15-35:5-10:0.1-0.3:0.1-0.3:1-3:0.05-0.

1.

7. The anti-sagging polyurethane waterproof coating according to claim 5, characterized in that: The dispersant is selected from one or both of F108 coating dispersant and 9250 dispersant; and / or, the defoamer is selected from one or more of BYK-066N defoamer, 5500 defoamer and organosilicon defoamer; and / or, the dehydrating agent is selected from vinyltrimethoxysilane A-171; and / or, the catalyst is selected from one or more of organotin NEOSTANN U-303, butyltin dilaurate, stannous octoate, zinc isooctanoate, bismuth isooctanoate, bismuth neodecanoate and zinc neodecanoate.

8. A method for preparing the anti-sagging polyurethane waterproof coating according to any one of claims 1-7, characterized in that: The method includes the step of mixing and dispersing the maleic anhydride-modified polyurethane, silane-modified powder, maleic anhydride-modified adhesive and other raw materials to obtain the anti-sagging polyurethane waterproof coating.

9. The method according to claim 8, characterized in that: The method further includes the step of preparing the maleic anhydride-modified polyurethane: adding the polyol to a reaction vessel, heating for dehydration, then adding maleic anhydride and a catalyst, and adding isocyanate dropwise for reaction, testing the NCO content of the system, and when the NCO content of the system is less than 6.1%, the reaction is complete, and the maleic anhydride-modified polyurethane is obtained; and / or, the method further includes the step of preparing the silane-modified powder: adding the powder to a dryer, then adding a solution of silane coupling agent for reaction, and dehydrating to obtain the silane-modified powder; and / or, the method further includes the step of preparing the maleic anhydride-modified gel: adding the gel and plasticizer to a reaction vessel, heating to a higher temperature, then adding maleic anhydride and an initiator for reaction, and obtaining the maleic anhydride-modified gel.

10. The use of the anti-sagging polyurethane waterproof coating according to any one of claims 1-7 for bonding asphalt rolls.

11. The use of the anti-sagging polyurethane waterproof coating according to any one of claims 1-7 as a primer for concrete substrates.

12. A waterproof laminate, comprising a substrate layer, an anti-sagging polyurethane waterproof coating layer, and an asphalt membrane layer, characterized in that: The anti-sagging polyurethane waterproof coating layer is formed by the anti-sagging polyurethane waterproof coating as described in any one of claims 1 to 7.

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