Asphalt-based waterproof coating and preparation method thereof

Abstract

The present application relates to the technical field of waterproof coatings, and specifically discloses an asphalt-based waterproof coating and a preparation method thereof. The asphalt-based waterproof coating is mainly made of the following raw materials in parts by weight: 40-60 parts of emulsified asphalt, 30-40 parts of acrylic acid-modified polyurethane emulsion, 2-4 parts of ethylene-acrylate-methacrylate glycidyl terpolymer, 1-3 parts of diethylene glycol butyl ether, 20-25 parts of modified titanium dioxide, 1-2 parts of thickener, 0.2-1 parts of dispersant, 0.1-0.5 parts of defoamer, and 0.05-0.15 parts of antioxidant. The asphalt-based waterproof coating, through the mutual coordination between the raw materials, not only has no cracks and no water seepage at -25°C, but also has the advantages of high tensile strength, high tear strength, and high bonding strength, showing excellent comprehensive performance, can adapt to industrial mass production, and has economic value.

Description

Technical Field

[0001] The present application relates to the technical field of waterproof coatings, and more specifically, to an asphalt-based waterproof coating and a preparation method thereof. Background Art

[0002] With the continuous development of the construction industry, people pay more and more attention to the waterproofness of buildings. Waterproof roll is a rollable sheet waterproof material, which needs to be cut according to the shape of the base layer. For complex base layers, multiple waterproof rolls need to be overlapped, and leakage points are prone to occur at the overlaps, affecting the waterproof effect. Based on this, some researchers have proposed asphalt-based waterproof coatings, which are mainly formulated with emulsified asphalt and emulsion. The asphalt-based waterproof coating is directly applied to the surface of the base layer, which can quickly form a dense film layer and has an effect similar to that of rubber roll. At the same time, asphalt-based waterproof coatings have the advantages of seamless connection and high bonding strength, and have received widespread attention and research. Some researchers have also added titanium dioxide to the raw materials to enhance the service life of asphalt-based waterproof coatings in order to improve the aging resistance of asphalt-based waterproof coatings. However, the applicant found in the study that although the addition of titanium dioxide can increase the aging resistance, the tensile strength and tear strength of the asphalt-based waterproof coating are reduced by the influence of titanium dioxide. Summary of the invention

[0003] In order to reduce the influence of titanium dioxide on the tensile strength and tear strength of asphalt-based waterproof coatings, the present application provides an asphalt-based waterproof coating and a preparation method thereof.

[0004] In the first aspect, the present application provides an asphalt-based waterproof coating, which adopts the following technical solution:

[0005] An asphalt-based waterproof coating is mainly made of the following raw materials in parts by weight: 40-60 parts of emulsified asphalt, 30-40 parts of acrylic acid-modified polyurethane emulsion, 2-4 parts of ethylene-acrylate-glycidyl methacrylate terpolymer, 1-3 parts of diethylene glycol butyl ether, 20-25 parts of modified titanium dioxide, 1-2 parts of thickener, 0.2-1 parts of dispersant, 0.1-0.5 parts of defoamer, and 0.05-0.15 parts of antioxidant.

[0006] The asphalt-based waterproof coating of the present application has a tensile strength of >5MPa, a tear strength of >840N, a dry base surface bonding strength of >1.5MPa, and a wet base surface bonding strength of >1.2MPa through the mutual coordination of the raw materials, reducing the influence of titanium dioxide on the asphalt-based waterproof coating, showing the advantages of high tensile strength, high tear strength, and high bonding strength. Moreover, it has no cracks and no water seepage at -25°C, showing excellent comprehensive performance, meeting higher requirements, being adaptable to industrial mass production, and having economic value.

[0007] Acrylic modified polyurethane emulsion is added to emulsified asphalt. Acrylic modified polyurethane emulsion can solidify after losing water, which effectively increases the elasticity and low-temperature flexibility of asphalt-based waterproof coatings. There are no cracks or water seepage at -25°C, which increases the waterproof performance. Titanium dioxide is also added to the raw materials. Titanium dioxide can not only increase the aging resistance of asphalt-based waterproof coatings, but also graft titanium dioxide and introduce a large number of active groups such as boron oxygen, silicon oxygen, ester, and carboxyl groups on the surface of titanium dioxide, increase the types and number of active groups on the surface of titanium dioxide, and the number of side chains, effectively increase the bonding strength between titanium dioxide and raw materials, reduce the impact of titanium dioxide on asphalt-based waterproof coatings, and improve the tensile strength, tear strength, and bonding strength of asphalt-based waterproof coatings.

[0008] Optionally, the modified titanium dioxide is prepared by the following method: adding titanium dioxide to water at a temperature of 70-90°C, ultrasonically treating for 20-40 minutes, then adding methanesulfonic acid, stirring for 20-40 minutes, then adding triallyl borate and 3-(methacryloyloxy)propyltrimethoxysilane, stirring for 3-5 hours, then adding trimethylolpropane triacrylate and maleic anhydride, stirring for 20-40 minutes, then adding an organic initiator, stirring for 3-5 hours, cooling to room temperature, filtering, washing, and drying to obtain modified titanium dioxide.

[0009] Optionally, the weight ratio of the titanium dioxide, methanesulfonic acid, triallyl borate, 3-(methacryloyloxy)propyltrimethoxysilane, trimethylolpropane triacrylate, maleic anhydride, and organic initiator is (10-20):(2-4):(1-3):(1-3):(0.5-1.5):(0.5-1.5):(0.02-0.05).

[0010] By adopting the above technical scheme, titanium dioxide is first dispersed, and then activated with methanesulfonic acid to increase the number of hydroxyl groups on the surface of titanium dioxide, and then grafted with triallyl borate and 3-(methacryloyloxy)propyl trimethoxysilane, and introduced boroxy, siloxy and ester groups on the surface of titanium dioxide. Then, trimethylolpropane triacrylate and maleic anhydride are grafted with an organic initiator, and carboxyl and ester groups are introduced on the surface of titanium dioxide, which greatly increases the types and number of active groups on the surface of titanium dioxide. Since triallyl borate contains three carbon-carbon double bonds and trimethylolpropane triacrylate also contains three carbon-carbon double bonds, the number of side chains on the surface of titanium dioxide is also greatly increased, thereby increasing the use effect of grafted modified nano titanium dioxide and improving the tensile strength, tear strength and bonding strength of asphalt-based waterproof coatings.

[0011] Furthermore, the weight ratio of titanium dioxide to water is (1-2):(8-12). At this time, the amount of water added is limited to facilitate the preparation of modified titanium dioxide.

[0012] The titanium dioxide is rutile titanium dioxide, and the mesh number of the titanium dioxide is 800-1340 mesh. In many embodiments, the mesh number of the titanium dioxide is 1000 mesh, and the mesh number can also be set to 800 mesh, 1340 mesh, etc. as needed.

[0013] Optionally, the organic initiator is one or more of di-tert-butyl peroxide, tert-butyl perbenzoate, and diisopropylbenzene peroxide.

[0014] By adopting the above technical scheme, di-tert-butyl peroxide, tert-butyl perbenzoate and diisopropylbenzene peroxide can all provide free radicals and initiate polymerization reactions. When the organic initiator is selected from di-tert-butyl peroxide, tert-butyl perbenzoate and diisopropylbenzene peroxide, the expected effect can be achieved.

[0015] Optionally, the emulsified asphalt is emulsified asphalt RHLQQ01; and the acrylic modified polyurethane emulsion is acrylic modified polyurethane emulsion X-PU698.

[0016] By adopting the above technical scheme, emulsified asphalt and acrylic modified polyurethane emulsion are limited, which facilitates the selection of emulsified asphalt and acrylic modified polyurethane emulsion and increases the stability of the performance of asphalt-based waterproof coatings.

[0017] Optionally, the thickener is polyacrylamide and cellulose ether, and the weight ratio of polyacrylamide to cellulose ether is (1-3):(2-4).

[0018] Furthermore, the polyacrylamide is anionic polyacrylamide, and the cellulose ether is hydroxyethyl cellulose ether. In multiple embodiments, the weight ratio of polyacrylamide to cellulose ether is 1:2, and the weight ratio can also be set to 1:4, 3:2, 3:4, 1:1, 2:3, etc. as needed.

[0019] Optionally, the dispersant is one or more of dioctyl sodium succinate sulfonate, sodium secondary alkyl sulfonate, and sodium dodecylbenzene sulfonate.

[0020] Optionally, the defoamer is one or more of silicone ether defoamer THIX-299, polyether defoamer THIX-288, and silicone defoamer THIX-278.

[0021] Optionally, the antioxidant is one or more of antioxidant 1010, antioxidant 1024, and antioxidant 1098.

[0022] By adopting the above technical solution, the dispersant, defoamer and antioxidant are limited, which facilitates the selection of the dispersant, defoamer and antioxidant.

[0023] In multiple embodiments, the dispersant is sodium dioctyl succinate sulfonate, and the dispersant can also be set to sodium secondary alkyl sulfonate, sodium dodecylbenzene sulfonate, etc. as needed. In multiple embodiments, the defoamer is THIX-299, a silicone ether defoamer, and the defoamer can also be set to polyether defoamer THIX-288, silicone defoamer THIX-278, etc. as needed. In multiple embodiments, the antioxidant is antioxidant 1010, and the antioxidant can also be set to antioxidant 1024, antioxidant 1098, etc. as needed.

[0024] In a second aspect, the present application provides a method for preparing the above-mentioned asphalt-based waterproof coating, which adopts the following technical solution:

[0025] A method for preparing the above-mentioned asphalt-based waterproof coating comprises the following steps: mixing acrylic modified polyurethane emulsion, ethylene-acrylate-glycidyl methacrylate terpolymer, diethylene glycol butyl ether, a dispersant, and a defoamer, then adding emulsified asphalt to mix, then adding modified titanium dioxide to mix, and then adding a thickener and an antioxidant to mix to obtain an asphalt-based waterproof coating.

[0026] By adopting the above technical solution, the preparation of asphalt-based waterproof coating is facilitated.

[0027] In summary, this application has at least the following beneficial effects:

[0028] 1. The asphalt-based waterproof coating of the present application adds titanium dioxide to the raw materials, and grafts the titanium dioxide to introduce a large number of active groups on the surface of titanium dioxide, which greatly increases the types and number of active groups on the surface of titanium dioxide and the number of branches, reduces the influence of titanium dioxide on the asphalt-based waterproof coating, and improves the tensile strength, tear strength and bonding strength of the asphalt-based waterproof coating. The tensile strength is greater than 5MPa, the tear strength is greater than 840N, the dry base surface bonding strength is greater than 1.5MPa, and the wet base surface bonding strength is greater than 1.2MPa. It shows excellent comprehensive performance, can adapt to industrial mass production, and has economic value.

[0029] 2. In the preparation method of modified titanium dioxide, methanesulfonic acid is first used to activate the surface of titanium dioxide, and then triallyl borate and 3-(methacryloyloxy)propyltrimethoxysilane are grafted, and then trimethylolpropane triacrylate and maleic anhydride are grafted. Since triallyl borate contains three carbon-carbon double bonds and three boroxy groups, 3-(methacryloyloxy)propyltrimethoxysilane contains a carbon-carbon double bond, an ester group, and three siloxy groups, trimethylolpropane triacrylate contains three carbon-carbon double bonds and three ester groups, and maleic anhydride is hydrolyzed in water and contains a carbon-carbon double bond and two carboxyl groups, not only the types and quantities of active groups on the surface of titanium dioxide are greatly increased, but also the polymerization reaction of multiple carbon-carbon double bonds is utilized to greatly increase the number of side chains on the surface of titanium dioxide, thereby enhancing the bonding strength between the modified titanium dioxide and the raw materials, and improving the tensile strength, tear strength and bonding strength of the asphalt-based waterproof coating. DETAILED DESCRIPTION

[0030] In order to make the present application easier to understand, the present application will be further described in detail below in conjunction with the examples, which are merely illustrative and are not intended to limit the scope of application of the present application. The raw materials or components used in the present application can be obtained through commercial routes or conventional methods unless otherwise specified.

[0031] Preparation Example

[0032] Preparation Example 1

[0033] A modified titanium dioxide is prepared by the following method:

[0034] At a temperature of 80°C and a speed of 400r / min, add 15g of titanium dioxide to 100g of water and ultrasonically treat for 30min. Then add 3g of methanesulfonic acid and stir for 40min. Then add 2g of triallyl borate and 2g of 3-(methacryloyloxy)propyltrimethoxysilane and stir for 4h. Then add 1g of trimethylolpropane triacrylate and 1g of maleic anhydride and stir for 30min. Then add 0.04g of di-tert-butyl peroxide and stir for 4h. Cool to 25°C and filter. Wash with water three times, using 50g of water each time. Then dry to obtain modified titanium dioxide.

[0035] Wherein, the titanium dioxide is rutile titanium dioxide with a mesh number of 1000 meshes, and is selected from Hebei Bangti Chemical Co., Ltd.

[0036] Preparation Example 2

[0037] A modified titanium dioxide, which differs from Preparation Example 1 in that the preparation method of the modified titanium dioxide is different, and is prepared by the following method:

[0038] At a temperature of 70°C and a speed of 500r / min, add 10g of titanium dioxide to 120g of water and ultrasonically treat for 20min. Then add 2g of methanesulfonic acid and stir for 40min. Then add 1g of triallyl borate and 3g of 3-(methacryloyloxy)propyltrimethoxysilane and stir for 3h. Then add 0.5g of trimethylolpropane triacrylate and 1.5g of maleic anhydride and stir for 40min. Then add 0.05g of di-tert-butyl peroxide and stir for 3h. Cool to 25°C and filter. Wash with water three times, using 50g of water each time. Then dry to obtain modified titanium dioxide.

[0039] Preparation Example 3

[0040] A modified titanium dioxide, which differs from Preparation Example 1 in that the preparation method of the modified titanium dioxide is different, and is prepared by the following method:

[0041] At a temperature of 90°C and a speed of 300r / min, add 20g of titanium dioxide to 80g of water and ultrasonically treat for 40min. Then add 4g of methanesulfonic acid and stir for 20min. Then add 3g of triallyl borate and 1g of 3-(methacryloyloxy)propyltrimethoxysilane and stir for 5h. Then add 1.5g of trimethylolpropane triacrylate and 0.5g of maleic anhydride and stir for 20min. Then add 0.02g of di-tert-butyl peroxide and stir for 5h. Cool to 25°C and filter. Wash with water three times, using 50g of water each time. Then dry to obtain modified titanium dioxide.

[0042] Example

[0043] Table 1 Content of each raw material of asphalt-based waterproof coating (unit: g)

[0044]

[0045] Example 1

[0046] An asphalt-based waterproof coating, the raw material ratio of which is shown in Table 1.

[0047] Among them, the emulsified asphalt is emulsified asphalt RHLQQ01, and is selected from Shandong Honggu Waterproof Materials Co., Ltd.; the acrylic modified polyurethane emulsion is acrylic modified polyurethane emulsion X-PU698, and is selected from Xinhua New Materials Technology Co., Ltd.; the ethylene-acrylate-methacrylate glycidyl terpolymer is selected from Dongguan Shenghao Plastic Raw Materials Co., Ltd.; the dispersant is dioctyl sodium sulfosuccinate; the defoamer is silicone ether defoamer THIX-299; and the antioxidant is antioxidant 1010.

[0048] The thickeners are polyacrylamide and cellulose ether, and the weight ratio of polyacrylamide to cellulose ether is 1:2. The polyacrylamide is anionic polyacrylamide, and the cellulose ether is hydroxyethyl cellulose ether. Both anionic polyacrylamide and hydroxyethyl cellulose ether are selected from Renqiu Pengyu Chemical Co., Ltd.; the modified titanium dioxide is prepared by Preparation Example 1.

[0049] A method for preparing an asphalt-based waterproof coating comprises the following steps:

[0050] At a speed of 400 r / min, ethylene-acrylate-methacrylate glycidyl ester terpolymer, diethylene glycol butyl ether, dispersant, and defoamer were added to the acrylic modified polyurethane emulsion and stirred for 10 minutes. Then, emulsified asphalt was added and stirred for 60 minutes. Then, modified titanium dioxide was added and stirred for 2 hours. Then, thickener and antioxidant were added and stirred for 20 minutes to obtain an asphalt-based waterproof coating.

[0051] Example 2

[0052] An asphalt-based waterproof coating, which is different from Example 1 in that the raw material ratio of the asphalt-based waterproof coating is different, and the raw material ratio is shown in Table 1.

[0053] Example 3

[0054] An asphalt-based waterproof coating, which is different from Example 1 in that the raw material ratio of the asphalt-based waterproof coating is different, and the raw material ratio is shown in Table 1.

[0055] Example 4

[0056] An asphalt-based waterproof coating, which differs from Example 1 in that the source of the modified titanium dioxide in the raw materials of the asphalt-based waterproof coating is different, and the modified titanium dioxide is prepared using Preparation Example 2.

[0057] Example 5

[0058] An asphalt-based waterproof coating, which differs from Example 1 in that the source of the modified titanium dioxide in the raw materials of the asphalt-based waterproof coating is different, and the modified titanium dioxide is prepared using Preparation Example 3.

[0059] Comparative Example

[0060] Comparative Example 1

[0061] An asphalt-based waterproof coating, which differs from Example 1 in that an equal amount of titanium dioxide is used to replace modified titanium dioxide in the raw materials of the asphalt-based waterproof coating.

[0062] Comparative Example 2

[0063] An asphalt-based waterproof coating, which differs from Example 1 in that, in the raw materials of the asphalt-based waterproof coating, in the preparation method of modified titanium dioxide, an equal amount of triallyl borate is used to replace 3-(methacryloyloxy)propyltrimethoxysilane.

[0064] Comparative Example 3

[0065] An asphalt-based waterproof coating, which differs from Example 1 in that, in the raw materials of the asphalt-based waterproof coating, in the preparation method of modified titanium dioxide, an equal amount of 3-(methacryloyloxy)propyltrimethoxysilane is used to replace triallyl borate.

[0066] Comparative Example 4

[0067] An asphalt-based waterproof coating, which differs from Example 1 in that, in the raw materials of the asphalt-based waterproof coating, in the preparation method of modified titanium dioxide, an equal amount of trimethylolpropane triacrylate is used to replace maleic anhydride.

[0068] Comparative Example 5

[0069] An asphalt-based waterproof coating, which differs from Example 1 in that, in the raw materials of the asphalt-based waterproof coating, in the preparation method of modified titanium dioxide, an equal amount of maleic anhydride is used to replace trimethylolpropane triacrylate.

[0070] Performance Testing

[0071] The asphalt-based waterproof coatings obtained in Examples 1-5 and Comparative Examples 1-5 were taken as samples respectively, and the following performance tests were performed on the samples according to GB / T16777-2008 “Test Methods for Building Waterproof Coatings”. The test results are shown in Table 2.

[0072] Table 2 Test results

[0073]

[0074] As can be seen from Table 2, the asphalt-based waterproof coating of the present application has high tensile strength and tear strength, with a tensile strength of 5.28-5.46MPa and a tear strength of 843-869N, showing high mechanical properties. It also has high bonding strength, with a dry base bonding strength of 1.53-1.68MPa and a wet base bonding strength of 1.26-1.43MPa, showing high bonding stability. At the same time, there are no cracks or water seepage at -25°C, which makes the asphalt-based waterproof coating show excellent comprehensive performance, suitable for industrial mass production, and has economic value.

[0075] Example 1 is compared with Comparative Examples 1-3. The titanium dioxide of Comparative Example 1 is not grafted; in the preparation method of the modified titanium dioxide of Comparative Example 2, triallyl borate is grafted first, and then trimethylolpropane triacrylate and maleic anhydride are grafted; in the preparation method of the modified titanium dioxide of Comparative Example 3, 3-(methacryloyloxy)propyltrimethoxysilane is grafted first, and then trimethylolpropane triacrylate and maleic anhydride are grafted; in the preparation method of the modified titanium dioxide of Example 1, triallyl borate and 3-(methacryloyloxy)propyltrimethoxysilane are grafted first, and then trimethylolpropane triacrylate and maleic anhydride are grafted. It can be seen from this that in the grafting modification of titanium dioxide, the synergistic enhancement between triallyl borate and 3-(methacryloyloxy)propyltrimethoxysilane is used to increase the types and number of surface active groups and the number of branches on titanium dioxide, increase the bonding strength between the modified titanium dioxide and the raw materials, and greatly improve the tensile strength, tear strength and bonding strength of the asphalt-based waterproof coating.

[0076] Example 1 is compared with Comparative Example 1 and Comparative Examples 4-5. The titanium dioxide of Comparative Example 1 is not grafted; in the preparation method of the modified titanium dioxide of Comparative Example 4, triallyl borate and 3-(methacryloyloxy)propyltrimethoxysilane are grafted first, and then trimethylolpropane triacrylate is grafted; in the preparation method of the modified titanium dioxide of Comparative Example 5, triallyl borate and 3-(methacryloyloxy)propyltrimethoxysilane are grafted first, and then maleic anhydride is grafted; in the preparation method of the modified titanium dioxide of Example 1, triallyl borate and 3-(methacryloyloxy)propyltrimethoxysilane are grafted first, and then trimethylolpropane triacrylate and maleic anhydride are grafted. From this, it can be seen that in the grafting modification of titanium dioxide, the synergistic enhancement between trimethylolpropane triacrylate and maleic anhydride increases the types and number of surface active groups of titanium dioxide and the number of branches, which significantly increases the use effect of modified titanium dioxide and makes the asphalt-based waterproof coating show better performance.

[0077] It should be noted that the embodiments described above are only used to explain the present application and do not constitute any limitation to the present application. The present application is described with reference to typical embodiments, but it should be understood that the words used therein are descriptive and explanatory words, rather than restrictive words. The present application may be modified as specified within the scope of the claims of the present application, and the present invention may be revised without departing from the scope and spirit of the present application. Although the present application described therein relates to specific methods, materials and embodiments, it does not mean that the present application is limited to the specific examples disclosed therein. On the contrary, the present application can be extended to all other methods and applications with the same functions.

Claims

1. An asphalt-based waterproof coating, characterized in that: It is mainly made of the following raw materials in parts by weight: 40-60 parts of emulsified asphalt, 30-40 parts of acrylic acid modified polyurethane emulsion, 2-4 parts of ethylene-acrylate-glycidyl methacrylate terpolymer, 1-3 parts of diethylene glycol butyl ether, 20-25 parts of modified titanium dioxide, 1-2 parts of thickener, 0.2-1 parts of dispersant, 0.1-0.5 parts of defoamer, and 0.05-0.15 parts of antioxidant; The modified titanium dioxide is prepared by the following method: adding titanium dioxide to water at a temperature of 70-90° C., ultrasonically treating for 20-40 minutes, then adding methanesulfonic acid, stirring for 20-40 minutes, then adding triallyl borate and 3-(methacryloyloxy)propyltrimethoxysilane, stirring for 3-5 hours, then adding trimethylolpropane triacrylate and maleic anhydride, stirring for 20-40 minutes, then adding an organic initiator, stirring for 3-5 hours, cooling to room temperature, filtering, washing, and drying to obtain the modified titanium dioxide; The weight ratio of the titanium dioxide, methanesulfonic acid, triallyl borate, 3-(methacryloyloxy)propyltrimethoxysilane, trimethylolpropane triacrylate, maleic anhydride and organic initiator is (10-20):(2-4):(1-3):(1-3):(0.5-1.5):(0.5-1.5):(0.02-0.05).

2. The asphalt-based waterproof coating according to claim 1, characterized in that: The organic initiator is one or more of di-tert-butyl peroxide, tert-butyl perbenzoate, and diisopropylbenzene peroxide.

3. The asphalt-based waterproof coating according to claim 1, characterized in that: The thickeners are polyacrylamide and cellulose ether, and the weight ratio of polyacrylamide to cellulose ether is (1-3):(2-4).

4. The asphalt-based waterproof coating according to claim 1, characterized in that: The dispersant is one or more of dioctyl sodium succinate sulfonate, sodium secondary alkyl sulfonate, and sodium dodecylbenzene sulfonate.

5. The asphalt-based waterproof coating according to claim 1, characterized in that: The defoamer is one or more of the silicone ether defoamer THIX-299, the polyether defoamer THIX-288, and the organosilicon defoamer THIX-278.

6. The asphalt-based waterproof coating according to claim 1, characterized in that: The antioxidant is one or more of antioxidant 1010, antioxidant 1024, and antioxidant 1098.

7. A method for preparing an asphalt-based waterproof coating according to any one of claims 1 to 6, characterized in that: The method comprises the following steps: mixing acrylic modified polyurethane emulsion, ethylene-acrylate-glycidyl methacrylate terpolymer, diethylene glycol butyl ether, dispersant and defoamer, then adding emulsified asphalt to mix, then adding modified titanium dioxide to mix, then adding thickener and antioxidant to mix, and obtaining asphalt-based waterproof coating.

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