Weather-resistant polyurethane waterproof coating and preparation method thereof

Abstract

The application 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 component A and component B;the preparation raw materials of the component A comprise diphenylmethane diisocyanate and polyether dihydric alcohol; and the preparation raw materials of the component B comprise polyether trihydric alcohol, water, a catalyst, a nano metal oxide, a coupling agent and a pigment and filler.The polyurethane waterproof coating is safe and environmentally friendly, the waterproof coating formed by curing has excellent weather resistance and mechanical properties, the preparation process is simple, the construction stability is high, and the polyurethane waterproof coating is suitable for waterproof engineering in building engineering, can improve the engineering quality and reduce the maintenance cost in the later period.The application further provides a preparation method and application of the polyurethane waterproof coating.

Description

TECHNICAL FIELD

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

[0002] Polyurethane, referred to as PU for short, is a high polymer material formed by polycondensation reaction of hydroxyl compounds and isocyanate, and has the characteristics of good mechanical properties and stable chemical properties, and is widely used in the field of building waterproof engineering due to its excellent comprehensive performance as a waterproof coating. With the continuous development of the construction engineering industry and the continuous improvement of environmental protection requirements, the requirements for waterproof coatings are gradually increasing. However, the traditional polyurethane waterproof coating still has defects such as containing volatile or toxic and harmful components, insufficient weather resistance, construction stability or mechanical properties, and still has a large room for improvement.

[0003] Therefore, it is necessary to further improve the polyurethane waterproof coating so that it has excellent weather resistance, construction stability and mechanical properties while meeting environmental protection requirements. SUMMARY

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

[0005] The present application also provides a preparation method of the polyurethane waterproof coating.

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

[0007] In a first aspect of the present application, a polyurethane waterproof coating is provided, comprising component A and component B.

[0008] The preparation raw materials of the component A include, by mass fraction, diphenylmethane diisocyanate 30-45 parts and polyether diol 55-70 parts.

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

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

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

[0012]

[0013] And in the present application, an excess of MDI is used in the A component, when the A component is mixed with the B component, in the presence of a catalyst, the excess of MDI further reacts with the polyether triol in the B component to produce a cross-linked network structure:

[0014]

[0015] The excess of MDI in the A component can also react with water in the B component to produce a polymer with cross-linking ability, so in the present application, there is no need to use a cross-linking agent such as 3,3'-dichloro-4,4'-diamino diphenyl methane (MOCA) additionally, further avoiding the presence of toxic and harmful substances in the prepared polyurethane waterproof coating. The reaction process of MDI with water is briefly written 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 with -NCO is faster than 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 application has a more complex polymer structure, and the complex cross-linked network structure provides better mechanical strength performance for the coating layer obtained by curing the coating.

[0016] The present application further dopes a proper amount of nano metal oxide particles in the polyurethane waterproof coating, the nano metal particles are dispersed and combined in the polymer structure in the coating, cooperate with the polymer, improve the stability of the cross-linked network structure, and can improve the properties of ultraviolet radiation resistance, chemical corrosion resistance and oxidation resistance of the coating, greatly improve the weather resistance of the waterproof coating, and prolong the service life of the waterproof coating. In addition, the present application uses a relatively excessive coupling agent in the B component, which can play a proper surface modification effect on 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 application, the mass ratio of the A component and the B component in the polyurethane waterproof coating is 2:3-5.

[0018] According to some embodiments of the present application, the raw materials for preparing the A component include, in terms of mass fraction, 35-40 parts of diphenyl methane diisocyanate and 60-65 parts of polyether diol.

[0019] According to some embodiments of the present application, the raw materials for preparing the B component include, in terms of mass fraction, 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 color filler.

[0020] The present application explores that the nano metal oxide added in the polyurethane waterproof coating needs to be within a suitable range, too little nano metal oxide is difficult to improve the weather resistance of the polyurethane waterproof coating, and too much nano metal oxide will affect the mechanical properties of the coating to a certain extent, thereby also adversely affecting the weather resistance, and increasing the cost of the coating.

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

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

[0023] The present application finds that the combination of titanium dioxide and zinc oxide has a better effect of improving the weather resistance of the polyurethane waterproof coating, and the use of two kinds of nano oxides can expand the ultraviolet resistance range, synergistically improve the chemical resistance and oxidation resistance of the coating, and further improve the service life of the coating.

[0024] According to some embodiments of the present application, the average particle size of the nano titanium dioxide ranges from 5 to 20 nm.

[0025] According to some embodiments of the present application, the average particle size of the nano zinc oxide ranges from 20 to 30 nm.

[0026] The present application uses nano titanium dioxide and nano zinc oxide with different particle size ranges, which can make the nano metal oxide better dispersed and play a role in the complex network structure of the polyurethane coating.

[0027] According to some embodiments of the present application, the A component further includes 4-6 parts of a first plasticizer.

[0028] According to some embodiments of the present application, the color filler of the B component includes color paste, silicon dioxide, talc, calcium carbonate and calcium hydroxide.

[0029] The color paste in the color filler is used for adjusting the color of the paint, more market demands are met, the silicon dioxide is nano silicon dioxide, the wear resistance of the coating is improved, the calcium carbonate and the talcum powder are used as the filling materials, the strength of the coating is improved, and the cost is reduced, and the calcium hydroxide can also be used for filling, and the CO2 generated in the curing process is absorbed, and the bubble generation is reduced.

[0030] According to some embodiments of the present application, the B component further comprises an auxiliary agent in a mass fraction of 14-18 parts.

[0031] According to some embodiments of the present application, the auxiliary agent of the B component comprises a second plasticizer, a dispersant and an antifoaming agent.

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

[0033] In the present application, a relatively excessive coupling agent is used, which can modify part of the filler, end-cap the polyurethane prepolymer, improve the binding performance of the paint, modify the surface of the nano metal oxide, make it fully dispersed in the paint, and better play the role of improving the weather resistance of the polyurethane waterproof coating.

[0034] In the second aspect of the present application, a method for preparing the polyurethane waterproof coating of the first aspect of the present application is provided, comprising the following steps:

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

[0036] S2, mixing the raw materials for preparation except for the catalyst, the nano metal oxide, the coupling agent and the color filler in the B component, then adding the remaining raw materials for preparation, and stirring to obtain the B component;

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

[0038] The preparation process of the present application is simple, the construction performance is good, and the polyurethane waterproof coating can be conveniently and quickly applied in building engineering waterproofing.

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

[0040] According to some embodiments of the present application, the stirring in step S1 is stirring for 30-90min under the condition that the temperature is kept at 70-90℃.

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

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

[0043] In a third aspect, the present application provides an application of the polyurethane waterproof coating in the waterproofing of construction engineering.

[0044] The polyurethane waterproof coating of the present application has good weather resistance, can greatly prolong the service life of the waterproof coating, improve the engineering quality, reduce the engineering cost, and has a broad application prospect in the waterproofing of construction engineering.

[0045] Other features and advantages of the present application will be set forth in the following description, and in part will become apparent to those skilled in the art upon examination of the following or can be learned by practice of the present application. DETAILED DESCRIPTION

[0046] The concept and the technical effects of the present application will be described clearly and completely in the following embodiments, so as to fully understand the purpose, features and effects of the present application. Obviously, the described embodiments are only some of the embodiments of the present application, but not all the embodiments. Based on the embodiments of the present application, other embodiments obtained by those skilled in the art without creative labor are within the protection scope of the present application.

[0047] The specific conditions not mentioned in the embodiments are carried out according to the conventional conditions or the conditions suggested by the manufacturers. The reagents or instruments not mentioned by the manufacturers are all conventional products that can be purchased in the market.

[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; the diphenyl methane diisocyanate (MDI) is T-50 purchased from Wanhua Chemical; the catalysts are FT13 catalyst purchased from Suzhou Fite Brother New Material Co., Ltd. and AUCAT-F1 catalyst purchased from Guangzhou Yourun Synthetic Material Co., Ltd.; the silicon dioxide is TSP-H10 nano silicon dioxide purchased from Jiangsu Tianxing New Material Co., Ltd.; the titanium dioxide is ZKKY-T10 nano titanium dioxide purchased from Zhongke Keye, with an average particle size of 10 nm; the zinc oxide is PZT-30 nano zinc oxide purchased from Nanjing Baokete New Material Co., Ltd., with an average particle size of 25 nm; the plasticizer is environmentally friendly plasticizer purchased from BASF Co., Ltd.; the silane coupling agent is KH-550 silane coupling agent purchased from Guangzhou Zhongjie New Material Co., Ltd.; the dispersant is FT201 dispersant purchased from Suzhou Fite Brother New Material Co., Ltd.; the defoaming agent is FT302 defoaming agent purchased from Suzhou Fite Brother New Material Co., Ltd.; and the talc powder is 1250-mesh talc powder purchased from Guangxi Guilin Shenghe Mineral Powder Co., Ltd.

[0049] Example 1

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

[0051] The polyurethane waterproof coating of the present embodiment contains component A and component B, and the compositions of the raw materials and the mass fractions of the two components are shown as follows:

[0052] Component A: diphenyl methane diisocyanate (MDI) 35 parts, polyether diol 65 parts, plasticizer 5 parts;

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

[0054] Among them, the catalysts are FT13 catalyst and AUCAT-F1 catalyst, each 0.5 part.

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

[0056] 1) Component A: according to the mass fractions of the above raw materials, first mix the polyether diol and the plasticizer, stir uniformly, heat to 80℃, then add MDI, keep stirring at 80℃ for 60 min, and discharge to obtain component A;

[0057] 2) B component: according to the mass fraction of each raw material above, first mix the polyether triol, water, plasticizer and dispersant, stir for 20 min, then add the catalyst, silicon dioxide, titanium dioxide, zinc oxide, silane coupling agent, defoaming agent, color paste, talc, calcium carbonate and calcium hydroxide, stir for 120 min, to obtain the B component;

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

[0059] Example 2

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

[0061] The polyurethane waterproof coating of the present embodiment contains an A component and a B component, and the composition of the two components and the mass fraction of each raw material are as follows:

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

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

[0064] Among them, the catalyst is FT13 catalyst and AUCAT-F1 catalyst, each 0.75 parts.

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

[0066] 1) A component: according to the mass fraction of each raw material above, first mix the polyether diol and the plasticizer, stir uniformly, heat to 80℃, then add the MDI, keep stirring at 80℃ for 60 min, and discharge to obtain the A component;

[0067] 2) B component: according to the mass fraction of each raw material above, first mix the polyether triol, water, plasticizer and dispersant, stir for 20 min, then add the catalyst, silicon dioxide, titanium dioxide, zinc oxide, silane coupling agent, defoaming agent, color paste, talc, calcium carbonate and calcium hydroxide, stir for 120 min, to obtain the B component;

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

[0069] Example 3

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

[0071] The polyurethane waterproof coating of the embodiment comprises component A and component B, and the component A and the component B are composed of the following raw materials and the mass fractions of the raw materials.

[0072] The component A comprises 40 parts of diphenylmethane diisocyanate (MDI), 60 parts of polyether diol and 5 parts of plasticizer.

[0073] The component B comprises 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 part of defoaming agent, 2 parts of color paste, 8 parts of talc, 6 parts of calcium carbonate and 4 parts of calcium hydroxide.

[0074] The catalyst comprises 0.5 part of FT13 catalyst and 0.5 part of AUCAT-F1 catalyst.

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

[0076] 1) The component A: according to the mass fractions of the raw materials, the polyether diol and the plasticizer are mixed and stirred uniformly, and then heated to 80 DEG C; then the MDI is added, and stirring is kept at 80 DEG C for 60 min; and then the component A is obtained.

[0077] 2) The component B: according to the mass fractions of the raw materials, the polyether triol, the water, the plasticizer and the dispersant are mixed and stirred for 20 min; then the catalyst, the silicon dioxide, the titanium dioxide, the zinc oxide, the silane coupling agent, the defoaming agent, the color paste, the talc, the calcium carbonate and the calcium hydroxide are mixed and stirred for 120 min; and then the component B is obtained.

[0078] 3) Before use, the component A and the component B are mixed according to the mass ratio of 1:2, and then stirred uniformly; and then the polyurethane waterproof coating is obtained.

[0079] Comparative Example 1

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

[0081] The polyurethane waterproof coating of the comparative example comprises component A and component B, and the component A and the component B are composed of the following raw materials and the mass fractions of the raw materials.

[0082] The component A comprises 40 parts of diphenylmethane diisocyanate (MDI), 60 parts of polyether diol and 5 parts of plasticizer.

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

[0084] The catalyst is FT13 catalyst and AUCAT-F1 catalyst, each 0.75 parts.

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

[0086] 1) Group A: according to the mass fraction of each raw material described above, first mix the polyether diol with the plasticizer, stir uniformly, heat to 80℃, then add MDI, keep stirring at 80℃ for 60 min, and then discharge to obtain Group A;

[0087] 2) Group B: according to the mass fraction of each raw material described above, first mix the polyether triol, water, plasticizer and dispersant, stir for 20 min, then mix the catalyst, silicon dioxide, titanium dioxide, zinc oxide, silane coupling agent, defoamer, color paste, talc, calcium carbonate and calcium hydroxide, stir for 120 min, and then obtain Group B;

[0088] 3) Before use, mix Group A and Group B according to the mass ratio of 1:2, stir uniformly, and then obtain the polyurethane waterproof coating.

[0089] Comparative Example 2

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

[0091] The polyurethane waterproof coating of the present comparative example contains Group A and Group B, and the composition of the raw materials and the mass fraction of the two groups are as follows:

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

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

[0094] The catalyst is FT13 catalyst and AUCAT-F1 catalyst, each 0.75 parts.

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

[0096] 1) A component: according to the mass fraction of each raw material above, first mix the polyether diol and plasticizer, stir uniformly, heat to 80°C, then add MDI, keep stirring at 80°C for 60 min, discharge to obtain the A component;

[0097] 2) B component: according to the mass fraction of each raw material above, first mix the polyether triol, water, plasticizer and dispersant, stir for 20 min, then add the catalyst, silica, titanium dioxide, zinc oxide, silane coupling agent, defoaming agent, color paste, talc, calcium carbonate and calcium hydroxide, stir for 120 min to obtain the B component;

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

[0099] Comparative Example 3

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

[0101] The polyurethane waterproof coating of the present comparative example contains A component and B component, and the composition of the two components and the mass fraction of each raw material are as follows:

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

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

[0104] Among them, the catalyst is FT13 catalyst and AUCAT-F1 catalyst, each 0.75 parts.

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

[0106] 1) A component: according to the mass fraction of each raw material above, first mix the polyether diol and plasticizer, stir uniformly, heat to 80°C, then add MDI, keep stirring at 80°C for 60 min, discharge to obtain the A component;

[0107] 2) B component: according to the mass fraction of each raw material above, first mix the polyether triol, water, plasticizer and dispersant, stir for 20 min, then add the catalyst, silica, titanium dioxide, zinc oxide, silane coupling agent, defoaming agent, color paste, talc, calcium carbonate and calcium hydroxide, stir for 120 min to obtain the B component;

[0108] 3) Before use, mix A component and B component according to mass ratio 1:2, stir uniformly, and the polyurethane waterproof coating is obtained.

[0109] Comparative Example 4

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

[0111] The polyurethane waterproof coating of the present comparative example contains A component and B component, and the composition of raw materials and the mass fraction of the two components are as follows:

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

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

[0114] Among them, the catalyst is FT13 catalyst and AUCAT-F1 catalyst, each 0.75 parts.

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

[0116] 1) A component: according to the mass fraction of each raw material above, first mix polyether diol and plasticizer, stir uniformly, heat to 80℃, then add MDI, keep stirring at 80℃ for 60 min, and the A component is obtained;

[0117] 2) B component: according to the mass fraction of each raw material above, first mix polyether triol, water, plasticizer and dispersant, stir for 20 min, then mix catalyst, silicon dioxide, titanium dioxide, zinc oxide, silane coupling agent, defoamer, color paste, talc, calcium carbonate and calcium hydroxide, stir for 120 min, and the B component is obtained;

[0118] 3) Before use, mix A component and B component according to mass ratio 1:2, stir uniformly, and the polyurethane waterproof coating is obtained.

[0119] Comparative Example 5

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

[0121] The polyurethane waterproof coating of the present comparative example contains A component and B component, and the composition of raw materials and the mass fraction of the two components are as follows:

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

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

[0124] Among them, the catalyst is FT13 catalyst and AUCAT-F1 catalyst, each 0.75 parts.

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

[0126] 1) Group A: according to the mass fraction of each raw material above, first mix the polyether diol with the plasticizer, stir uniformly, heat to 80℃, then add MDI, keep stirring at 80℃ for 60min, and then discharge to obtain Group A;

[0127] 2) Group B: according to the mass fraction of each raw material above, first mix the polyether triol, water, plasticizer and dispersant, stir for 20min, then mix the catalyst, silicon dioxide, titanium dioxide, zinc oxide, silane coupling agent, defoamer, color paste, talc, calcium carbonate and calcium hydroxide, stir for 120min, and then obtain Group B;

[0128] 3) Before use, mix Group A and Group B according to the mass ratio of 1:2, stir uniformly, and then obtain the polyurethane waterproof coating.

[0129] Comparative Example 6

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

[0131] The polyurethane waterproof coating of the present comparative example contains Group A and Group B, and the composition raw materials and their mass fractions of the two groups are as follows:

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

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

[0134] Among them, the catalyst is FT13 catalyst and AUCAT-F1 catalyst, each 0.75 parts.

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

[0136] 1) A component: according to the mass fraction of each raw material above, first mix the polyether diol and plasticizer, stir uniformly, heat to 80℃, then add MDI, keep stirring at 80℃ for 60 min, discharge to obtain A component;

[0137] 2) B component: according to the mass fraction of each raw material above, first mix the polyether triol, water, plasticizer and dispersant, stir for 20 min, then mix the catalyst, silicon dioxide, titanium dioxide, zinc oxide, silane coupling agent, defoaming agent, color paste, talc, calcium carbonate and calcium hydroxide, stir for 120 min to obtain B component;

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

[0139] The mass fraction of each raw material of A and B components of the polyurethane waterproof coating of each example and comparative example is shown in Table 1, wherein the auxiliary agent of B component is the combination of catalyst, silane coupling agent, dispersant and defoaming agent, and the pigment and filler is the combination of color paste, talc, calcium carbonate and calcium hydroxide.

[0140] Table 1: Mass fraction of raw materials of examples and comparative examples

[0141]

[0142] Performance test:

[0143] The polyurethane waterproof coating prepared by examples 1-3 and comparative examples 1-6 and a brand of commercially available two-component polyurethane waterproof coating were compared and tested, and the performance test was carried out according to the standards of GB / T 19250-2013 “Polyurethane Waterproof Coating” and TBT / 2965-2018 “Waterproof Layer of Railway Bridge Concrete Bridge Deck”, and the test results are shown in Table 2.

[0144] Table 2: Performance test results of each example and comparative example and commercially available polyurethane waterproof coating

[0145]

[0146]

[0147] From the above test results, it can be seen that the polyurethane waterproof coating prepared by the scheme of the present application has good tensile strength, elongation at break, peel strength and water impermeability, and after artificial climate aging treatment, heat treatment, acid treatment and alkali treatment, the tensile strength retention rate and elongation at break are relatively higher than those of the polyurethane waterproof coating on the market, which shows that the polyurethane waterproof coating prepared by the scheme of the present application has more excellent weather resistance, better construction stability, prolongs the service life of building products and reduces maintenance cost.

[0148] From the test results of Comparative Examples 1, 2 and 3, it can be seen that when the amount of silane coupling agent or nano metal oxide is reduced compared to the present application, 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 climate aging treatment, heat treatment, acid treatment and alkali treatment are decreased to different degrees, and the decrease is obviously increased compared to the examples, showing poorer weather resistance. It is believed that in the present application, by introducing a suitable amount of metal oxide nanoparticles, nano titanium dioxide and nano zinc oxide, the stability of the crosslinked network structure of the polymer in the polyurethane waterproof coating can be appropriately improved, the dispersed nano metal particles support the crosslinked network and rigid segments in the polymer, and 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; in combination with the use of excess silane coupling agent, the nano metal oxide particles can be appropriately surface modified, and longer stirring and dispersion can make them better combined and dispersed in the waterproof coating mixture; in addition, the incorporation of a suitable amount of metal nano oxide also helps to improve the viscosity of the polyurethane waterproof coating, thereby improving the flexibility of the coating after forming, which helps 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 high, the mechanical properties of the polyurethane waterproof coating will be affected to some extent, and the improvement of its durability is not helpful.

[0149] As can be seen from Comparative Examples 5 and 6, the combination of nano titanium dioxide and nano zinc oxide in the present application can provide a wider range of anti-ultraviolet radiation, synergistically improve the chemical resistance and oxidation resistance of the coating, and due to the difference in particle size, the nano metal oxide particles can be better dispersed in the polyurethane coating to improve the weather resistance of the coating.

[0150] The above embodiments of the present application have been described in detail, but the present application is not limited to the above embodiments, and various changes can be made within the scope of knowledge possessed by those skilled in the art without departing from the purpose of the present application. In addition, the embodiments of the present application and the features in the embodiments can be combined with each other without conflict.

Claims

1. A polyurethane waterproofing coating, characterized in that, The polyurethane waterproof coating comprises an A component and a B component. The A component is prepared from 30-45 parts by mass of diphenylmethane diisocyanate and 55-70 parts by mass of polyether diol. The B component is prepared from 40-60 parts by mass of polyether triol, 4-10 parts by mass of water, 0.5-2 parts by mass of catalyst, 8-11 parts by mass of nano metal oxide, 5-8 parts by mass of coupling agent and 22-27 parts by mass of pigment and filler. The nano metal oxide is composed of nano titanium dioxide and nano zinc oxide, and the mass ratio of the nano titanium dioxide to the nano zinc oxide is 1:0.5-2. The average particle size of the nano titanium dioxide ranges from 5 nm to 20 nm, and the average particle size of the nano zinc oxide ranges from 20 nm to 30 nm.

2. The polyurethane waterproofing coating according to claim 1, characterized in that, The coupling agent is a silane coupling agent.

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

4. The polyurethane waterproofing coating according to claim 3, characterized in that, The B component further comprises 14-18 parts by mass of an auxiliary agent.

5. A method for preparing the polyurethane waterproof coating according to any one of claims 1 to 4, characterized in that, The auxiliary agent comprises a second plasticizer, a dispersant and an antifoaming agent. The polyurethane waterproof coating comprises the following steps: S1, heating the raw materials for preparing the A component except for the diphenylmethane diisocyanate, and then adding the diphenylmethane diisocyanate and stirring to obtain the A component; S2, mixing the raw materials for preparing the B component except for the catalyst, the nano metal oxide, the coupling agent and the pigment and filler, and then adding the remaining raw materials and stirring to obtain the B component; 6. The method of claim 5, wherein, S3, mixing the A component and the B component to obtain the polyurethane waterproof coating.

7. The method of claim 5, wherein, The heating temperature in the step S1 is 70-90℃. The stirring time in the step S2 is greater than 90 min.

8. The polyurethane waterproof coating according to any one of claims 1-4 for use in waterproofing of building engineering.

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