Weather-resistant polyurethane waterproof coating and preparation method thereof

Abstract

The invention belongs to the technical field of polyurethane coatings, and particularly discloses a weather-resistant polyurethane waterproof coating and a preparation method thereof. The polyurethane waterproof coating comprises a component A and a component B, wherein the component A is prepared from the following raw materials: diphenylmethane diisocyanate and polyether glycol; and the component B is prepared from the following raw materials: polyether triol, water, a catalyst, a nano metal oxide, a coupling agent and a pigment filler. The polyurethane waterproof coating is safe and environment-friendly, the cured waterproof coating has excellent weather resistance and mechanical property, the preparation process is simple, the construction stability is high, the polyurethane waterproof coating is suitable for waterproof engineering in constructional engineering, the engineering quality can be improved, and the later maintenance cost can be reduced. The invention also provides a preparation method and application of the polyurethane waterproof coating.

Description

Technical Field

[0001] The invention relates to the technical field of polyurethane coatings, and in particular to a weather-resistant polyurethane waterproof coating and a preparation method thereof. Background Art

[0002] Polyurethane, also known as polyurethane (PU), is a polymer material formed by the polycondensation reaction of hydroxyl compounds and isocyanates. It has good mechanical properties and stable chemical properties. As a waterproof coating, it has excellent comprehensive performance and is widely used in the field of building waterproof engineering. With the continuous development of the construction industry and the continuous improvement of environmental protection requirements, the requirements for waterproof coatings are gradually increasing. However, traditional polyurethane waterproof coatings still have defects such as containing volatile or toxic and harmful components, insufficient weather resistance, construction stability or mechanical properties, and there is still much room for improvement.

[0003] Therefore, it is necessary to further improve the polyurethane waterproof coating so that it can meet environmental protection requirements while having excellent weather resistance, construction stability, mechanical properties and other properties. Summary of the invention

[0004] The present invention aims to solve at least one of the technical problems existing in the prior art. To this end, the present invention provides a polyurethane waterproof coating. The polyurethane waterproof coating of the present invention has good environmental protection, good weather resistance and mechanical strength, high construction stability, and is suitable for waterproofing projects in construction projects.

[0005] The invention also provides a method for preparing the polyurethane waterproof coating.

[0006] The invention also provides application of the polyurethane waterproof coating.

[0007] A first aspect of the present invention provides a polyurethane waterproof coating, comprising component A and component B;

[0008] Wherein, the raw materials for preparing the A component include, by weight: 30 to 45 parts of diphenylmethane diisocyanate and 55 to 70 parts of polyether diol;

[0009] The raw materials for preparing the B component include, by weight: 40-60 parts of polyether triol, 4-10 parts of water, 0.5-2 parts of catalyst, 8-11 parts of nano metal oxide, 5-8 parts of coupling agent and 22-27 parts of pigment and filler.

[0010] According to a specific embodiment of the present invention, the polyurethane waterproof coating provided by the present invention has at least the following beneficial effects:

[0011] The polyurethane waterproof coating of the present invention is a two-component coating, wherein the diphenylmethane diisocyanate (MDI) and the polyether diol of the A component are raw materials for synthesizing polyurethane. The present invention uses MDI to replace the traditional TDI, thereby avoiding the toxicity and irritating odor of the product; the two functional groups of the isocyanate (-NCO) of MDI react with the hydroxyl (-OH) of the polyether diol to produce a carbamate structure:

[0012]

[0013] In the solution of the present invention, an excess amount of MDI is used in component A. When component A is mixed with component B, in the presence of a catalyst, the excess MDI further reacts with the polyether triol in component B to produce a cross-linked network structure:

[0014]

[0015] The excess MDI in component A can also react with the water in component B to produce a polymer with cross-linking ability. Therefore, in the scheme of the present invention, there is no need to use an additional cross-linking agent such as 3,3′-dichloro-4,4′-diaminodiphenylmethane (MOCA), further avoiding the presence of toxic and harmful substances in the prepared polyurethane waterproof coating. Among them, the reaction process of MDI and water is abbreviated as: nONC-R-NCO+2nH2O→nHOOCNH-R-NHCOOH→nH2N-R-NH2+2nCO2; nONC-R-NCO+nH2N-R-NH2→(NH-R-NHCONH-R-NHCO)n; since the reaction of -NH2 and -NCO is faster than that of water, the above reaction can be written as: 2nONC-R-NCO+2nH2O→(NH-R-NHCONH-R-NHCO)n+2nCO2; therefore, the polyurethane waterproof coating of the present invention has a more complex polymer structure, and the complex cross-linked network structure provides better mechanical strength properties for the coating obtained by curing the coating.

[0016] The scheme of the present invention further dopes an appropriate amount of nano metal oxide particles in the polyurethane waterproof coating, and the nano metal particles are dispersed and combined in the polymer structure of the coating, and cooperate with the polymer to improve the stability of the cross-linked network structure, and can improve the coating's resistance to ultraviolet radiation, chemical corrosion and oxidation resistance, greatly improve the weather resistance of the waterproof coating, and extend the working life of the waterproof coating. In addition, the scheme of the present invention uses a relatively excessive amount of coupling agent in component B, which can play a role in appropriate surface modification of the nano metal oxide, so that it is better combined and dispersed in the polyurethane waterproof coating.

[0017] According to some embodiments of the present invention, the mass ratio of the component A to the component B in the polyurethane waterproof coating is 2:3-5.

[0018] According to some embodiments of the present invention, the raw materials for preparing component A include, by mass, 35 to 40 parts of diphenylmethane diisocyanate and 60 to 65 parts of polyether diol.

[0019] According to some embodiments of the present invention, the raw materials for preparing component B include, by mass, 45-55 parts of polyether triol, 5-8 parts of water, 1-1.5 parts of catalyst, 9-10 parts of nano metal oxide, 6-7 parts of coupling agent and 23-26 parts of pigment filler.

[0020] The present invention explores and finds that the nano metal oxide added to the polyurethane waterproof coating needs to be within a suitable range. Too little nano metal oxide will hardly improve the weather resistance of the polyurethane waterproof coating, while too much nano metal oxide will affect the mechanical properties of the coating to a certain extent, which will also have an adverse effect on the weather resistance and increase the cost of the coating.

[0021] According to some embodiments of the present invention, the nano metal oxide includes nano titanium dioxide and nano zinc oxide.

[0022] According to some embodiments of the present invention, the mass ratio of nano titanium dioxide to nano zinc oxide in the nano metal oxide is 1:0.5-2.

[0023] The present invention finds that the combination of titanium dioxide and zinc oxide has the effect of better improving the weather resistance of the polyurethane waterproof coating. The two nano-oxides are used together to expand the UV resistance range and synergistically improve the chemical resistance and oxidation resistance of the coating. In addition, they can also play an antibacterial role to a certain extent, further improving the service life of the coating.

[0024] According to some embodiments of the present invention, the average particle size of the nano titanium dioxide is in the range of 5 to 20 nm.

[0025] According to some embodiments of the present invention, the average particle size of the nano zinc oxide is in the range of 20 to 30 nm.

[0026] The invention uses nano titanium dioxide and nano zinc oxide in different particle size ranges, so that the nano metal oxide can be better dispersed and play a role in the complex network structure of the polyurethane coating.

[0027] According to some embodiments of the present invention, the component A further comprises 4 to 6 parts by weight of a first plasticizer.

[0028] According to some embodiments of the present invention, the pigments and fillers of component B include color paste, silicon dioxide, talc, calcium carbonate and calcium hydroxide.

[0029] In the scheme of the present invention, the color paste in the color filler is used to adjust the color of the coating to meet more market demands; the silicon dioxide is nano silicon dioxide, which helps to improve the wear resistance of the coating; calcium carbonate and talcum powder are used as filling materials, which also help to improve the strength of the coating and reduce costs; calcium hydroxide can also play a filling role and absorb CO2 generated during the curing and molding process to reduce the generation of bubbles.

[0030] According to some embodiments of the present invention, the component B further comprises 14 to 18 parts by weight of an auxiliary agent.

[0031] According to some embodiments of the present invention, the auxiliary agent of component B includes a second plasticizer, a dispersant and a defoaming agent.

[0032] According to some embodiments of the present invention, the coupling agent is a silane coupling agent.

[0033] In the scheme of the present invention, a relatively excessive amount of coupling agent is used, so that it can not only modify part of the filler and end-cap the polyurethane prepolymer, thereby improving the bonding performance of the coating, but also modify the surface of the nano metal oxide so that it is fully dispersed and combined with the polymer in the coating, thereby better playing its role in improving the weather resistance of the polyurethane waterproof coating.

[0034] The second aspect of the present invention provides a method for preparing the polyurethane waterproof coating according to the first aspect of the present invention, comprising the following steps:

[0035] S1, heating the preparation raw materials except diphenylmethane diisocyanate in the A component, adding diphenylmethane diisocyanate, and stirring to obtain the A component;

[0036] S2, mixing the raw materials except the catalyst, nano metal oxide, coupling agent and pigment filler in the B component, adding the remaining raw materials, stirring, and obtaining the B component;

[0037] S3, mixing the component A with the component B to obtain the polyurethane waterproof coating.

[0038] The solution of the present invention has a simple preparation process and good construction performance, and can be conveniently and quickly applied in waterproofing of construction projects.

[0039] According to some embodiments of the present invention, the heating temperature in step S1 is 70-90°C.

[0040] According to some embodiments of the present invention, the stirring in step S1 is to maintain the temperature at 70 to 90° C. and stir for 30 to 90 minutes.

[0041] According to some embodiments of the present invention, the stirring time of step S2 is greater than 90 min.

[0042] According to some embodiments of the present invention, the step S3 is specifically to mix the component A and the component B in a mass ratio of 2:3-5.

[0043] The third aspect of the present invention provides the use of the polyurethane waterproof coating described in the first aspect of the present invention in waterproofing of construction projects.

[0044] The coating formed by curing the polyurethane waterproof coating of the present invention has good weather resistance, can greatly extend the working life of the waterproof coating, improve project quality, reduce project costs, and has broad application prospects in waterproofing of construction projects.

[0045] Other features and advantages of the present invention will be set forth in the description which follows, and in part will be apparent from the description, or may be learned by practice of the present invention. DETAILED DESCRIPTION

[0046] The following will be combined with the embodiments to clearly and completely describe the concept of the present invention and the technical effects produced, so as to fully understand the purpose, characteristics and effects of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of them. Based on the embodiments of the present invention, other embodiments obtained by those skilled in the art without creative work are all within the scope of protection of the present invention.

[0047] If the specific conditions are not specified in the examples, the experiments were carried out under conventional conditions or conditions recommended by the manufacturer. If the manufacturers of the reagents or instruments are not specified, they are all conventional products that can be purchased commercially.

[0048] The polyether diol used in the specific embodiment is DL-2000D polyether polyol purchased from Bluestar Dongda Chemical Co., Ltd., with a molecular weight of 2000, a functionality of 2, and a hydroxyl value of 54.5-57.5; the polyether triol is EP-330N polyether polyol purchased from Bluestar Dongda Chemical Co., Ltd., with a molecular weight of 5000, a functionality of 3, and a hydroxyl value of 32.5-35.5; diphenylmethane diisocyanate (MDI) is T-50 purchased from Wanhua Chemical; the catalyst is FT13 catalyst purchased from Suzhou Feite Brothers New Materials Co., Ltd. and AUCAT-F1 catalyst purchased from Guangzhou Yourun Synthetic Materials Co., Ltd.; the silicon dioxide is purchased from Jiangsu Tianxing New Materials Co., Ltd. TSP-H10 nano-silicon dioxide; titanium dioxide is ZKKY-T10 nano-titanium dioxide purchased from Zhongke Keyou, with an average particle size of 10nm; zinc oxide is PZT-30 nano-zinc oxide purchased from Nanjing Baoket New Materials Co., Ltd., with an average particle size of 25nm; the plasticizer is an environmentally friendly plasticizer purchased from BASF Co., Ltd.; the silane coupling agent is KH-550 silane coupling agent purchased from Guangzhou Zhongjie New Materials Co., Ltd.; the dispersant is FT201 dispersant purchased from Suzhou Feite Brothers New Materials Co., Ltd.; the defoamer is FT302 defoamer purchased from Suzhou Feite Brothers New Materials Co., Ltd.; and the talc is 1250 mesh talc purchased from Guangxi Guilin Shenghe Mineral Powder Co., Ltd.

[0049] Example 1

[0050] This embodiment provides a polyurethane waterproof coating and a preparation method thereof.

[0051] The polyurethane waterproof coating of this embodiment contains component A and component B. The constituent raw materials of the two components and their mass fractions are as follows:

[0052] Component A: 35 parts of diphenylmethane diisocyanate (MDI), 65 parts of polyether diol, and 5 parts of plasticizer;

[0053] Component B: 50 parts of polyether triol, 1 part of catalyst, 5 parts of water, 3 parts of silicon dioxide, 4 parts of titanium dioxide, 5 parts of zinc oxide, 15 parts of plasticizer, 6 parts of silane coupling agent, 1 part of dispersant, 0.5 parts of defoamer, 2 parts of color paste, 8 parts of talc, 8 parts of calcium carbonate, 4 parts of calcium hydroxide;

[0054] The catalysts are 0.5 parts of FT13 catalyst and AUCAT-F1 catalyst, respectively.

[0055] The preparation steps of the polyurethane waterproof coating of this embodiment are as follows:

[0056] 1) Component A: According to the mass proportions of the above raw materials, first mix the polyether diol and the plasticizer, stir evenly, heat to 80°C, then add MDI, keep stirring at 80°C for 60 minutes, and discharge to obtain component A;

[0057] 2) Component B: firstly mix the polyether triol, water, plasticizer and dispersant according to the mass fractions of the above raw materials, stir for 20 minutes, then add the catalyst, silicon dioxide, titanium dioxide, zinc oxide, silane coupling agent, defoamer, color paste, talcum powder, calcium carbonate and calcium hydroxide, stir for 120 minutes, and obtain component B;

[0058] 3) Before use, mix component A and component B in a mass ratio of 1:2 and stir evenly to obtain a polyurethane waterproof coating.

[0059] Example 2

[0060] This embodiment provides a polyurethane waterproof coating and a preparation method thereof.

[0061] The polyurethane waterproof coating of this embodiment contains component A and component B. The constituent raw materials of the two components and their mass fractions are as follows:

[0062] Component A: 40 parts of diphenylmethane diisocyanate (MDI), 60 parts of polyether diol, and 5 parts of plasticizer;

[0063] Component B: 55 parts of polyether triol, 1.5 parts of catalyst, 7 parts of water, 4 parts of silicon dioxide, 5 parts of titanium dioxide, 4 parts of zinc oxide, 14 parts of plasticizer, 6 parts of silane coupling agent, 1.5 parts of dispersant, 0.5 parts of defoamer, 2 parts of color paste, 8 parts of talc, 6 parts of calcium carbonate, 4 parts of calcium hydroxide;

[0064] The catalysts are 0.75 parts of FT13 catalyst and AUCAT-F1 catalyst, respectively.

[0065] The preparation steps of the polyurethane waterproof coating of this embodiment are as follows:

[0066] 1) Component A: According to the mass proportions of the above raw materials, first mix the polyether diol and the plasticizer, stir evenly, heat to 80°C, then add MDI, keep stirring at 80°C for 60 minutes, and discharge to obtain component A;

[0067] 2) Component B: firstly mix the polyether triol, water, plasticizer and dispersant according to the mass fractions of the above raw materials, stir for 20 minutes, then add the catalyst, silicon dioxide, titanium dioxide, zinc oxide, silane coupling agent, defoamer, color paste, talcum powder, calcium carbonate and calcium hydroxide, stir for 120 minutes, and obtain component B;

[0068] 3) Before use, mix component A and component B in a mass ratio of 1:2 and stir evenly to obtain a polyurethane waterproof coating.

[0069] Example 3

[0070] This embodiment provides a polyurethane waterproof coating and a preparation method thereof.

[0071] The polyurethane waterproof coating of this embodiment contains component A and component B. The constituent raw materials of the two components and their mass fractions are as follows:

[0072] Component A: 40 parts of diphenylmethane diisocyanate (MDI), 60 parts of polyether diol, and 5 parts of plasticizer;

[0073] Component B: 40 parts of polyether triol, 1 part of catalyst, 8 parts of water, 4 parts of silicon dioxide, 5 parts of titanium dioxide, 5 parts of zinc oxide, 14 parts of plasticizer, 7 parts of silane coupling agent, 1.5 parts of dispersant, 0.5 parts of defoamer, 2 parts of color paste, 8 parts of talc, 6 parts of calcium carbonate, 4 parts of calcium hydroxide;

[0074] The catalysts are 0.5 parts of FT13 catalyst and AUCAT-F1 catalyst, respectively.

[0075] The preparation steps of the polyurethane waterproof coating of this embodiment are as follows:

[0076] 1) Component A: According to the mass proportions of the above raw materials, first mix the polyether diol and the plasticizer, stir evenly, heat to 80°C, then add MDI, keep stirring at 80°C for 60 minutes, and discharge to obtain component A;

[0077] 2) Component B: firstly mix the polyether triol, water, plasticizer and dispersant according to the mass fractions of the above raw materials, stir for 20 minutes, then add the catalyst, silicon dioxide, titanium dioxide, zinc oxide, silane coupling agent, defoamer, color paste, talcum powder, calcium carbonate and calcium hydroxide, stir for 120 minutes, and obtain component B;

[0078] 3) Before use, mix component A and component B in a mass ratio of 1:2 and stir evenly to obtain a polyurethane waterproof coating.

[0079] Comparative Example 1

[0080] This comparative example provides a polyurethane waterproof coating and a preparation method thereof.

[0081] The polyurethane waterproof coating of this comparative example contains component A and component B. The constituent raw materials of the two components and their mass fractions are as follows:

[0082] Component A: 40 parts of diphenylmethane diisocyanate (MDI), 60 parts of polyether diol, and 5 parts of plasticizer;

[0083] Component B: 55 parts of polyether triol, 1.5 parts of catalyst, 7 parts of water, 4 parts of silicon dioxide, 5 parts of titanium dioxide, 4 parts of zinc oxide, 14 parts of plasticizer, 2 parts of silane coupling agent, 1.5 parts of dispersant, 0.5 parts of defoamer, 2 parts of color paste, 10 parts of talc, 7 parts of calcium carbonate, 5 parts of calcium hydroxide;

[0084] The catalysts are 0.75 parts of FT13 catalyst and AUCAT-F1 catalyst, respectively.

[0085] The preparation steps of the polyurethane waterproof coating of this comparative example are as follows:

[0086] 1) Component A: According to the mass proportions of the above raw materials, first mix the polyether diol and the plasticizer, stir evenly, heat to 80°C, then add MDI, keep stirring at 80°C for 60 minutes, and discharge to obtain component A;

[0087] 2) Component B: firstly mix the polyether triol, water, plasticizer and dispersant according to the mass fractions of the above raw materials, stir for 20 minutes, then add the catalyst, silicon dioxide, titanium dioxide, zinc oxide, silane coupling agent, defoamer, color paste, talcum powder, calcium carbonate and calcium hydroxide, stir for 120 minutes, and obtain component B;

[0088] 3) Before use, mix component A and component B in a mass ratio of 1:2 and stir evenly to obtain a polyurethane waterproof coating.

[0089] Comparative Example 2

[0090] This comparative example provides a polyurethane waterproof coating and a preparation method thereof.

[0091] The polyurethane waterproof coating of this comparative example contains component A and component B. The constituent raw materials of the two components and their mass fractions are as follows:

[0092] Component A: 40 parts of diphenylmethane diisocyanate (MDI), 60 parts of polyether diol, and 5 parts of plasticizer;

[0093] Component B: 55 parts of polyether triol, 1.5 parts of catalyst, 7 parts of water, 4 parts of silicon dioxide, 2 parts of titanium dioxide, 2 parts of zinc oxide, 14 parts of plasticizer, 6 parts of silane coupling agent, 1.5 parts of dispersant, 0.5 parts of defoamer, 2 parts of color paste, 10 parts of talc, 8 parts of calcium carbonate, 5 parts of calcium hydroxide;

[0094] The catalysts are 0.75 parts of FT13 catalyst and AUCAT-F1 catalyst, respectively.

[0095] The preparation steps of the polyurethane waterproof coating of this comparative example are as follows:

[0096] 1) Component A: According to the mass proportions of the above raw materials, first mix the polyether diol and the plasticizer, stir evenly, heat to 80°C, then add MDI, keep stirring at 80°C for 60 minutes, and discharge to obtain component A;

[0097] 2) Component B: firstly mix the polyether triol, water, plasticizer and dispersant according to the mass fractions of the above raw materials, stir for 20 minutes, then add the catalyst, silicon dioxide, titanium dioxide, zinc oxide, silane coupling agent, defoamer, color paste, talcum powder, calcium carbonate and calcium hydroxide, stir for 120 minutes, and obtain component B;

[0098] 3) Before use, mix component A and component B in a mass ratio of 1:2 and stir evenly to obtain a polyurethane waterproof coating.

[0099] Comparative Example 3

[0100] This comparative example provides a polyurethane waterproof coating and a preparation method thereof.

[0101] The polyurethane waterproof coating of this comparative example contains component A and component B. The constituent raw materials of the two components and their mass fractions are as follows:

[0102] Component A: 40 parts of diphenylmethane diisocyanate (MDI), 60 parts of polyether diol, and 5 parts of plasticizer;

[0103] Component B: 55 parts of polyether triol, 1.5 parts of catalyst, 7 parts of water, 4 parts of silicon dioxide, 2 parts of titanium dioxide, 2 parts of zinc oxide, 14 parts of plasticizer, 2 parts of silane coupling agent, 1.5 parts of dispersant, 0.5 parts of defoamer, 2 parts of color paste, 12 parts of talc, 9 parts of calcium carbonate, 6 parts of calcium hydroxide;

[0104] The catalysts are 0.75 parts of FT13 catalyst and AUCAT-F1 catalyst, respectively.

[0105] The preparation steps of the polyurethane waterproof coating of this comparative example are as follows:

[0106] 1) Component A: According to the mass proportions of the above raw materials, first mix the polyether diol and the plasticizer, stir evenly, heat to 80°C, then add MDI, keep stirring at 80°C for 60 minutes, and discharge to obtain component A;

[0107] 2) Component B: firstly mix the polyether triol, water, plasticizer and dispersant according to the mass fractions of the above raw materials, stir for 20 minutes, then add the catalyst, silicon dioxide, titanium dioxide, zinc oxide, silane coupling agent, defoamer, color paste, talcum powder, calcium carbonate and calcium hydroxide, stir for 120 minutes, and obtain component B;

[0108] 3) Before use, mix component A and component B in a mass ratio of 1:2 and stir evenly to obtain a polyurethane waterproof coating.

[0109] Comparative Example 4

[0110] This comparative example provides a polyurethane waterproof coating and a preparation method thereof.

[0111] The polyurethane waterproof coating of this comparative example contains component A and component B. The constituent raw materials of the two components and their mass fractions are as follows:

[0112] Component A: 40 parts of diphenylmethane diisocyanate (MDI), 60 parts of polyether diol, and 5 parts of plasticizer;

[0113] Component B: 55 parts of polyether triol, 1.5 parts of catalyst, 7 parts of water, 4 parts of silicon dioxide, 7 parts of titanium dioxide, 7 parts of zinc oxide, 14 parts of plasticizer, 6 parts of silane coupling agent, 1.5 parts of dispersant, 0.5 parts of defoamer, 2 parts of color paste, 6 parts of talc, 5 parts of calcium carbonate, 2 parts of calcium hydroxide;

[0114] The catalysts are 0.75 parts of FT13 catalyst and AUCAT-F1 catalyst, respectively.

[0115] The preparation steps of the polyurethane waterproof coating of this comparative example are as follows:

[0116] 1) Component A: According to the mass proportions of the above raw materials, first mix the polyether diol and the plasticizer, stir evenly, heat to 80°C, then add MDI, keep stirring at 80°C for 60 minutes, and discharge to obtain component A;

[0117] 2) Component B: firstly mix the polyether triol, water, plasticizer and dispersant according to the mass fractions of the above raw materials, stir for 20 minutes, then add the catalyst, silicon dioxide, titanium dioxide, zinc oxide, silane coupling agent, defoamer, color paste, talcum powder, calcium carbonate and calcium hydroxide, stir for 120 minutes, and obtain component B;

[0118] 3) Before use, mix component A and component B in a mass ratio of 1:2 and stir evenly to obtain a polyurethane waterproof coating.

[0119] Comparative Example 5

[0120] This comparative example provides a polyurethane waterproof coating and a preparation method thereof.

[0121] The polyurethane waterproof coating of this comparative example contains component A and component B. The constituent raw materials of the two components and their mass fractions are as follows:

[0122] Component A: 40 parts of diphenylmethane diisocyanate (MDI), 60 parts of polyether diol, and 5 parts of plasticizer;

[0123] Component B: 55 parts of polyether triol, 1.5 parts of catalyst, 7 parts of water, 4 parts of silicon dioxide, 9 parts of titanium dioxide, 14 parts of plasticizer, 6 parts of silane coupling agent, 1.5 parts of dispersant, 0.5 parts of defoamer, 2 parts of color paste, 8 parts of talc, 6 parts of calcium carbonate, 4 parts of calcium hydroxide;

[0124] The catalysts are 0.75 parts of FT13 catalyst and AUCAT-F1 catalyst, respectively.

[0125] The preparation steps of the polyurethane waterproof coating of this comparative example are as follows:

[0126] 1) Component A: According to the mass proportions of the above raw materials, first mix the polyether diol and the plasticizer, stir evenly, heat to 80°C, then add MDI, keep stirring at 80°C for 60 minutes, and discharge to obtain component A;

[0127] 2) Component B: firstly mix the polyether triol, water, plasticizer and dispersant according to the mass fractions of the above raw materials, stir for 20 minutes, then add the catalyst, silicon dioxide, titanium dioxide, zinc oxide, silane coupling agent, defoamer, color paste, talcum powder, calcium carbonate and calcium hydroxide, stir for 120 minutes, and obtain component B;

[0128] 3) Before use, mix component A and component B in a mass ratio of 1:2 and stir evenly to obtain a polyurethane waterproof coating.

[0129] Comparative Example 6

[0130] This comparative example provides a polyurethane waterproof coating and a preparation method thereof.

[0131] The polyurethane waterproof coating of this comparative example contains component A and component B. The constituent raw materials of the two components and their mass fractions are as follows:

[0132] Component A: 40 parts of diphenylmethane diisocyanate (MDI), 60 parts of polyether diol, and 5 parts of plasticizer;

[0133] Component B: 55 parts of polyether triol, 1.5 parts of catalyst, 7 parts of water, 4 parts of silicon dioxide, 9 parts of zinc oxide, 14 parts of plasticizer, 6 parts of silane coupling agent, 1.5 parts of dispersant, 0.5 parts of defoamer, 2 parts of color paste, 8 parts of talc, 6 parts of calcium carbonate, 4 parts of calcium hydroxide;

[0134] The catalysts are 0.75 parts of FT13 catalyst and AUCAT-F1 catalyst, respectively.

[0135] The preparation steps of the polyurethane waterproof coating of this comparative example are as follows:

[0136] 1) Component A: According to the mass proportions of the above raw materials, first mix the polyether diol and the plasticizer, stir evenly, heat to 80°C, then add MDI, keep stirring at 80°C for 60 minutes, and discharge to obtain component A;

[0137] 2) Component B: firstly mix the polyether triol, water, plasticizer and dispersant according to the mass fractions of the above raw materials, stir for 20 minutes, then add the catalyst, silicon dioxide, titanium dioxide, zinc oxide, silane coupling agent, defoamer, color paste, talcum powder, calcium carbonate and calcium hydroxide, stir for 120 minutes, and obtain component B;

[0138] 3) Before use, mix component A and component B in a mass ratio of 1:2 and stir evenly to obtain a polyurethane waterproof coating.

[0139] The amounts of the raw materials used in components A and B of the polyurethane waterproof coatings of the embodiments and comparative examples are shown in Table 1, wherein the auxiliary agent of component B is a combination of a catalyst, a silane coupling agent, a dispersant and a defoamer, and the color filler is a combination of color paste, talcum powder, calcium carbonate and calcium hydroxide.

[0140] Table 1. Table of the dosage of raw materials in the examples and comparative examples

[0141]

[0142] Performance Test:

[0143] The polyurethane waterproof coatings prepared in Examples 1 to 3 and Comparative Examples 1 to 6 were compared with a certain brand of commercially available two-component polyurethane waterproof coatings, and performance tests were carried out in accordance with the standards of GB / T 19250-2013 "Polyurethane Waterproof Coatings" and TBT / 2965-2018 "Railway Bridge Concrete Deck Waterproof Layer". The test results are shown in Table 2.

[0144] Table 2 Performance test results of various embodiments and comparative examples and commercially available polyurethane waterproof coatings

[0145]

[0146]

[0147] From the above test results, it can be seen that the polyurethane waterproof coating prepared using the scheme of the present invention has good tensile strength, elongation at break, peel strength and impermeability, and after artificial weather aging treatment, heat treatment, acid treatment and alkali treatment, it has relatively higher tensile strength retention rate and elongation at break than the polyurethane waterproof coating on the market, indicating that the polyurethane waterproof coating prepared by the invention scheme has better weather resistance, better construction stability, extends the life of building products, and reduces maintenance costs.

[0148] It can be seen from the test results of Comparative Examples 1, 2 and 3 that when the amount of silane coupling agent or nano metal oxide is reduced compared with the solution of the present invention, the mechanical properties of the polyurethane waterproof coating are not greatly affected, but the tensile strength retention rate and elongation at break of the waterproof coating after artificial weathering treatment, heat treatment, acid treatment and alkali treatment will decrease to varying degrees, and the degree of decrease is significantly increased compared with the embodiment, showing worse weather resistance. The analysis shows that by introducing a suitable amount of metal oxide nanoparticles, nano titanium dioxide and nano zinc oxide, in the invention scheme, the stability of the polymer cross-linked network structure in the polyurethane waterproof coating can be appropriately improved. The dispersed nano metal particles support the cross-linked network and rigid segments in the polymer. In addition, the anti-ultraviolet radiation and antibacterial effects of nano titanium dioxide and nano zinc oxide improve the chemical resistance and oxidation resistance of the coating, which can further enhance the weather resistance of the waterproof coating. Combined with the use of excessive silane coupling agent, the nano metal oxide particles can be appropriately surface modified, and with longer stirring and dispersion, they can be better combined and dispersed in the waterproof coating mixture. In addition, the addition of a suitable amount of metal nano oxides can also help to improve the viscosity of the polyurethane waterproof coating, thereby improving the flexibility of the coating after molding, and helping to improve the durability of the coating in some specific use scenarios. In comparative example 4, when the amount of nano metal oxide is too much, it will affect the mechanical properties of the polyurethane waterproof coating to a certain extent, and it will not help much to improve its durability.

[0149] It can be seen from Comparative Examples 5 and 6 that the nano-metal oxide in the scheme of the present invention uses a combination of nano-titanium dioxide and nano-zinc oxide to provide a wider range of UV resistance, synergistically improve the chemical resistance and oxidation resistance of the coating, and due to the difference in particle size between the two, the nano-metal oxide particles are better dispersed in the polyurethane coating and play a role, thereby comprehensively improving the weather resistance of the coating.

[0150] The above is a detailed description of the embodiments of the present invention, but the present invention is not limited to the above embodiments. Various changes can be made within the knowledge of ordinary technicians in the relevant technical field without departing from the purpose of the present invention. In addition, the embodiments of the present invention and the features in the embodiments can be combined with each other without conflict.

Claims

1. A polyurethane waterproof coating, characterized in that: It includes component A and component B; The raw materials for preparing the component A include, by weight: 30 to 45 parts of diphenylmethane diisocyanate and 55 to 70 parts of polyether diol; The raw materials for preparing the B component include, by weight: 40-60 parts of polyether triol, 4-10 parts of water, 0.5-2 parts of catalyst, 8-11 parts of nano metal oxide, 5-8 parts of coupling agent and 22-27 parts of pigment and filler.

2. The polyurethane waterproof coating according to claim 1, characterized in that: The nano metal oxide includes nano titanium dioxide and nano zinc oxide.

3. The polyurethane waterproof coating according to claim 2, characterized in that: The mass ratio of nano titanium dioxide to nano zinc oxide in the nano metal oxide is 1:0.5-2; Preferably, the average particle size of the nano titanium dioxide is in the range of 5 to 20 nm, and the average particle size of the nano zinc oxide is in the range of 20 to 30 nm.

4. The polyurethane waterproof coating according to claim 1, characterized in that: The coupling agent is a silane coupling agent.

5. The polyurethane waterproof coating according to claim 1, characterized in that: The component A further comprises 4 to 6 parts by weight of a first plasticizer.

6. The polyurethane waterproof coating according to claim 1, characterized in that: The B component also includes 14 to 18 parts by weight of an auxiliary agent; Preferably, the auxiliary agent includes a second plasticizer, a dispersant and a defoaming agent.

7. A method for preparing the polyurethane waterproof coating according to any one of claims 1 to 6, characterized in that: The following steps are involved: S1, heating the preparation raw materials except diphenylmethane diisocyanate in the A component, adding diphenylmethane diisocyanate, and stirring to obtain the A component; S2, mixing the raw materials except the catalyst, nano metal oxide, coupling agent and pigment filler in the B component, adding the remaining raw materials, stirring, and obtaining the B component; S3, mixing the component A with the component B to obtain the polyurethane waterproof coating.

8. The preparation method according to claim 7, characterized in that: The heating temperature in step S1 is 70-90°C.

9. The preparation method according to claim 7, characterized in that: The stirring time of step S2 is greater than 90 minutes.

10. Use of the polyurethane waterproof coating according to any one of claims 1 to 6 in waterproofing of construction projects.

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