Water-based polyurethane waterproof coating and preparation method thereof

Abstract

The present application relates to a kind of water-based polyurethane waterproof coating applied with waterproofing membrane, including by mass fraction: polyether polyol 50~250 parts, diisocyanate 10~60 parts, modified crosslinking agent 1~10 parts, 1,4-butanediol 1~20 parts, ethylenediamine 2~10 parts, trimethylolpropane 2~10 parts, catalyst 2~10 parts, triethylamine 2~10 parts, organic solvent 30~100 parts, rutile titanium dioxide 10~100 parts, filler 100~800 parts, environmental protection type film forming aid 10~100 parts, other auxiliary agent 6.6~45 parts, the rest is water;The modified crosslinking agent is prepared by trifunctional aziridine, trishydroxymethyl aminomethyl methane, ethylene glycol di (3-mercaptopropionate), methyl methacrylate trifluoroethyl ester and 3-(2,3-epoxypropoxy) propyl methyl diethoxysilane, N,N-dimethylformamide and p-benzenesulfonic acid.The present application introduces modified crosslinking agent in water-based polyurethane system, so that the adhesion of coating and waterproofing membrane is firm and the peel strength is significantly improved, and the durability of the waterproof effect of coating and roll composite layer is improved.

Description

Technical Field

[0001] This invention relates to the field of waterproof coating technology, and in particular to a water-based polyurethane waterproof coating for composite application with waterproof membranes and its preparation method. Background Technology

[0002] During building construction, roofs and slabs are often used as transfer and storage areas for construction materials, making them prone to structural cracking due to frequent vibrations or excessive loads. Therefore, flexible waterproofing materials are needed to construct a reliable and durable defense. The "coating-roll composite waterproofing technology," developed in recent years, overcomes the shortcomings of traditional waterproofing construction processes and has achieved excellent application results. Specifically, it involves combining asphalt-based or polymer-based waterproofing rolls with waterproof coatings to achieve a waterproofing effect.

[0003] Water-based polyurethane waterproof coatings use water as the main dispersion medium. They not only retain some of the excellent properties of traditional solvent-based polyurethane, but also have advantages such as low production cost, safety and non-flammability, no environmental pollution, no damage to the coated surface, and easy operation. They are suitable for waterproofing projects in various scenarios such as roofs, exterior walls, interiors, roads and bridges.

[0004] However, in actual use, water-based polyurethane waterproof coatings and asphalt-based or polymer waterproof membranes have problems such as poor adhesion and easy peeling and detachment, which reduces the waterproof effect of the coating-mesh composite waterproof layer.

[0005] Therefore, it is necessary to provide a new type of water-based polyurethane waterproof coating that can be adapted to waterproof membranes so that a strong composite waterproof layer can be formed when the two are combined. Summary of the Invention

[0006] The technical problem to be solved by the present invention is: the present invention provides a water-based polyurethane waterproof coating for composite application with waterproof membrane and its preparation method. The prepared water-based polyurethane waterproof coating has high adhesion to the waterproof membrane and is not easy to peel off, effectively improving the waterproof effect of the coating-membrane composite layer. Moreover, no protective layer is required in the actual construction process, which greatly shortens the construction period and reduces material costs.

[0007] To solve the above-mentioned technical problems, the technical solution adopted by the present invention is as follows:

[0008] This invention provides a water-based polyurethane waterproof coating for composite application with waterproof membranes, comprising, by weight:

[0009] The composition includes: 50-250 parts polyether polyol, 10-60 parts diisocyanate, 1-10 parts modified crosslinking agent, 1-20 parts 1,4-butanediol, 2-10 parts ethylenediamine, 2-10 parts trimethylolpropane, 2-10 parts catalyst, 2-10 parts triethylamine, 30-100 parts organic solvent, 10-100 parts rutile titanium dioxide, 100-800 parts filler, 10-100 parts environmentally friendly film-forming aid, 6.6-45 parts other additives, and the balance being water.

[0010] The modified crosslinking agent is prepared by means of trifunctional aziridine, trihydroxymethylaminomethane, ethylene glycol di(3-mercaptopropionate), trifluoroethyl methacrylate, 3-(2,3-epoxypropoxy)propylmethyldiethoxysilane, N,N-dimethylformamide and p-benzenesulfonic acid.

[0011] This invention proposes a waterborne polyurethane waterproof coating for composite application with waterproof membranes. By introducing a modified crosslinking agent into the waterborne polyurethane system, the adhesion strength and peel strength between the coating and the waterproof membrane are significantly improved, thus enhancing the durability of the waterproof effect of the coating-membrane composite layer. The modified crosslinking agent of this invention first forms a backbone through the reaction of trifunctional aziridine and tris(hydroxymethyl)aminomethane, then reacts with ethylene glycol di(3-mercaptopropionate) to generate flexible segments, thereby forming a dendritic backbone compound. This compound is then polymerized and grafted with the double bonds in trifluoroethyl methacrylate. Furthermore, the introduction of 3-(2,3-epoxypropoxy)propylmethyldiethoxysilane results in a final dendritic hyperbranched oligomer crosslinking agent with a unique cavity structure. On the one hand, the modified crosslinking agent contains silicon-oxygen bonds within its cavity, which can encapsulate inorganic particles, resulting in a tight bond between them and the waterproof coating. On the other hand, the modified crosslinking agent's side chains contain various active groups such as carbonyl and ether groups, which can form hydrogen bonds with organic molecular chains, making the entanglement between organic molecular chains tighter and improving the reactivity between the dissolved waterproof membrane surface and the coating film. Furthermore, the presence of fluorine segments in the modified crosslinking agent's molecular chains further enhances the coating's hydrophobicity and toughness. In addition, the waterborne polyurethane waterproofing prepared by this invention also possesses excellent comprehensive properties such as mechanical properties, weather resistance, and low-temperature flexibility, making it highly suitable for waterproofing exposed roofs and slabs.

[0012] Preferably, the preparation method of the modified crosslinking agent includes the following steps:

[0013] Dissolve 10-20 parts of trifunctional aziridine and 10-20 parts of tris(hydroxymethyl)aminomethane in ethanol, and control the reaction temperature at 50-60℃. Then add 1-10 parts of ethylene glycol di(3-mercaptopropionate), 1-10 parts of trifluoroethyl methacrylate, and 1-20 parts of 3-(2,3-epoxypropoxy)propylmethyldiethoxysilane. React for 1-2 hours, raise the temperature to 70-80℃, add 1-30 parts of N,N-dimethylformamide and 1-20 parts of p-benzenesulfonic acid, and react for 2-3 hours. Cool down and discharge the product.

[0014] Preferably, the environmentally friendly film-forming aid is at least one of sucrose fatty acid polyester, isosorbide, tributyl citrate, epoxidized linseed oil, and epoxidized fatty acid methyl ester.

[0015] As described above, the present invention uses bio-based compounds such as sucrose fatty acid polyester as film-forming aids. During the process of coating and waterproof membrane compounding, these compounds can slightly dissolve the PE film of asphalt-based waterproof membrane and the surface layer of polymer waterproof membrane without damaging the membrane itself. This allows the coating and waterproof membrane to naturally fuse into a whole, avoiding the problem of easy peeling between water-based polyurethane waterproof coating and waterproof membrane due to poor bonding ability.

[0016] Preferably, the polyether polyol is at least one selected from polypropylene glycol, polycarbonate polyol, and polyester diol;

[0017] The diisocyanate is toluene diisocyanate;

[0018] The catalyst is at least one of dibutyltin dilaurate and stannous isooctanoate;

[0019] The organic solvent is acetone;

[0020] The filler is at least one of quartz powder, wollastonite powder, calcium carbonate, barium sulfate, and metakaolin.

[0021] Preferably, the other additives comprise, by weight:

[0022] Dispersant 1-10 parts, defoamer 4-10 parts, pH adjuster 0.5-5 parts, preservative 1-10 parts, polyurethane rheology modifier 0.1-10 parts.

[0023] Preferably, the dispersant is at least one selected from polyacrylate, polyphosphate, polycarboxylate, cellulose derivative, fatty acid polyethylene glycol ester, and sodium dodecyl sulfate;

[0024] The defoamer is at least one of polydimethylsiloxane, polyoxyethylene polyoxypropylene pentaerythritol ether, polyoxyethylene polyoxypropylene alcohol ether, and polyoxypropylene polyoxyethylene glycerol ether.

[0025] The pH adjuster is at least one of ammonia, dimethylethanolamine, 2-amino-2-methyl-1-propanol and triethanolamine;

[0026] The preservative is at least one of octyl-isothiazolinone, benzimidazole carbamate, and ethylene bis(dithiocarbamate) ammonium;

[0027] The polyurethane rheology modifier is at least one of hydrophobic group-modified ethoxy polyurethane polymer and polyurethane associative polymer.

[0028] Another aspect of the present invention provides a method for preparing the above-mentioned coating, comprising the following steps:

[0029] S1. The dehydrated polyether polyol, diisocyanate and catalyst are reacted at 68~72℃ for 0.8~1.2h under nitrogen protection;

[0030] S2. Cool to 48~50℃, then continue to add organic solvent, environmentally friendly film-forming aid and modified crosslinking agent and stir for at least 0.5h;

[0031] S3. Heat to 68~72℃, then add 1,4-butanediol and trimethylolpropane, reflux under condensation, and react for 1.5~2.5h.

[0032] S4. Cool to 23~27℃, add triethylamine, and stir for at least 0.5h;

[0033] S5. Prepare a solution of ethylenediamine and add it to the reaction solution of step S4. Emulsify and disperse for at least 0.5 h, then remove the organic solvent by rotary evaporation.

[0034] S6. Cool down to 30℃, add some water, stir for 3 minutes, then add rutile titanium dioxide, filler, other additives and the remaining water, and stir until well mixed.

[0035] Preferably, in step S4, the stirring speed is 550~650 rpm; in step S5, the stirring speed is 1400~1600 rpm, the rotary evaporation temperature is 35~45℃, and the rotary evaporation time is 3.5~4.5 h; in step S6, the stirring speed is 500 rpm. Attached Figure Description

[0036] Figure 1 The effects of Example 1 and Comparative Example 4 before peeling off different waterproof membranes: (a) Polymer waterproof membrane / Example 1, (b) Polymer waterproof membrane / Comparative Example 4, (c) SBS bitumen waterproof membrane / Example 1, (d) SBS bitumen waterproof membrane / Comparative Example 4.

[0037] Figure 2The effects of peeling off different waterproof membranes after combining Example 1 and Comparative Example 4 are shown: (a) Polymer waterproof membrane / Example 1, (b) Polymer waterproof membrane / Comparative Example 4, (c) SBS bitumen waterproof membrane / Example 1, (d) SBS bitumen waterproof membrane / Comparative Example 4. Detailed Implementation

[0038] To better understand the above technical solutions, exemplary embodiments of the present invention will be described in more detail below with reference to the accompanying drawings. Although exemplary embodiments of the present invention are shown in the drawings, it should be understood that the present invention can be implemented in various forms and should not be limited to the embodiments set forth herein. Rather, these embodiments are provided so that the present invention can be understood more clearly and thoroughly, and that the scope of the present invention can be fully conveyed to those skilled in the art.

[0039] Example 1

[0040] A water-based polyurethane waterproof coating for composite application with waterproof membranes, comprising, by weight:

[0041] 130 parts of polyether polyol (polypropylene glycol), 30 parts of diisocyanate (toluene diisocyanate), 5 parts of modified crosslinking agent, 10 parts of 1,4-butanediol, 5 parts of ethylenediamine, 5 parts of trimethylolpropane, 5 parts of catalyst (dibutyltin dilaurate), 5 parts of triethylamine, 40 parts of organic solvent (acetone), 30 parts of rutile titanium dioxide, 400 parts of filler (barium sulfate), 20 parts of environmentally friendly film-forming aid (sucrose fatty acid polyester), 12 parts of other additives, and the balance is water;

[0042] The modified crosslinking agent is prepared by means of trifunctional aziridine, trihydroxymethylaminomethane, ethylene glycol di(3-mercaptopropionate), trifluoroethyl methacrylate, 3-(2,3-epoxypropoxy)propylmethyldiethoxysilane, N,N-dimethylformamide and p-benzenesulfonic acid.

[0043] The other additives include, by weight:

[0044] Dispersant (sodium polyacrylate) 2 parts, defoamer (polyoxypropylene polyoxyethylene glycerol ether) 5 parts, pH adjuster (triethanolamine) 1 part, preservative (octyl-isothiazolinone) 2 parts, polyurethane rheology modifier (polyurethane associative polymer) 2 parts.

[0045] The preparation method of the modified crosslinking agent includes the following steps:

[0046] Dissolve 15 parts of trifunctional aziridine and 15 parts of trihydroxymethylaminomethane in ethanol, and control the reaction temperature at 50-60℃. Then add 6 parts of ethylene glycol di(3-mercaptopropionate), 5 parts of trifluoroethyl methacrylate, and 10 parts of 3-(2,3-epoxypropoxy)propylmethyldiethoxysilane. React for 1-2 hours, raise the temperature to 70-80℃, add 10 parts of N,N-dimethylformamide and 5 parts of p-benzenesulfonic acid, and react for 2-3 hours. Cool down and discharge the product.

[0047] It is prepared by the following method, including the following steps:

[0048] S1. The dehydrated polyether polyol, diisocyanate and catalyst are reacted at 68~72℃ for 0.8~1.2h under nitrogen protection;

[0049] S2. Cool to 48~50℃, then continue to add organic solvent, environmentally friendly film-forming aid and modified crosslinking agent and stir for at least 0.5h;

[0050] S3. Heat to 68~72℃, then add 1,4-butanediol and trimethylolpropane, reflux under condensation, and react for 1.5~2.5h.

[0051] S4. Cool to 23~27℃, add triethylamine, and stir at 550~650 rpm for at least 0.5 hours;

[0052] S5. Prepare an ethylenediamine aqueous solution with a volume ratio of 1:20 to water, and add it to the reaction solution in step S4. Adjust the rotation speed to 1400~1600 rpm, emulsify and disperse for at least 0.5 h, and then rotary evaporate at 35~45℃ for 3.5~4.5 h to remove organic solvents.

[0053] S6. Cool down to 30℃, add some water, stir at 500rpm for 3 minutes, then add rutile titanium dioxide, filler, other additives and the remaining water, and stir until well mixed.

[0054] Example 2

[0055] The main difference between this embodiment and Embodiment 1 is that the amount of modified crosslinking agent used is different; its mass part is 1 part.

[0056] The main difference between this embodiment and Embodiment 1 is that the amount of the environmentally friendly film-forming aid is different, and its mass part is 10 parts.

[0057] Comparative Example 1

[0058] The difference between this comparative example and Example 1 is that it does not contain modified crosslinking agents and environmentally friendly film-forming aids.

[0059] Comparative Example 2

[0060] The difference between this comparative example and Example 1 is that it does not contain environmentally friendly film-forming aids.

[0061] Comparative Example 3

[0062] The difference between this comparative example and Example 1 is that it does not contain a modified crosslinking agent.

[0063] Comparative Example 4

[0064] This comparative example uses commercially available conventional water-based polyurethane waterproof coating products.

[0065] The waterproof coatings prepared in Examples 1-3 and Comparative Examples 1-3 were subjected to performance tests, and the results are recorded in Tables 1 and 2.

[0066] Table 1 Performance Test Results

[0067]

[0068] Table 1 shows that the water-based polyurethane waterproof coating prepared in Examples 1-3 of this invention, when used in conjunction with waterproof membranes, not only possesses excellent weather resistance, stain resistance, and tensile properties, but also exhibits good peel performance with both polymer waterproof membranes and asphalt waterproof membranes. This meets the requirements for direct composite use with waterproof membranes and is suitable for waterproofing exposed roofs and slabs, reducing the need for protective layers and saving construction time and costs. In contrast, the waterproof coatings prepared in Comparative Example 2 (without environmentally friendly film-forming aids) and Comparative Example 3 (without modified crosslinking agents) failed to meet the standard peel performance requirements with waterproof membranes.

[0069] Table 2 Results of Hazardous Substance Content Tests

[0070] project VOC / (g / L) Comparative Example 1 Comparative Example 2 Comparative Example 3 Example 1 Example 2 Example 3 VOC / (g / L) ≤30 5 6 6 4 6 5 Benzene + Toluene + Ethylbenzene + Xylene / (mg / kg) ≤20 Not detected Not detected Not detected Not detected Not detected Not detected Formaldehyde content (mg / kg) ≤50 Not detected Not detected Not detected Not detected Not detected Not detected Ammonia (mg / kg) ≤300 Not detected Not detected Not detected Not detected Not detected Not detected

[0071] As shown in Table 2, the waterborne polyurethane waterproof coating prepared according to the present invention for composite application with waterproof membrane has low VOC content, meets the Class A standard requirements, and is environmentally friendly and long-lasting.

[0072] The composite performance of the waterborne polyurethane waterproof coatings of Example 1 and Comparative Example 4 with waterproof membranes was tested, and the results were recorded in [the relevant documentation]. Figure 1 and 2 As shown.

[0073] like Figure 1 and 2 As shown, conventional water-based polyurethane waterproof coatings (Comparative Example 4) cannot reliably bond with non-polar materials (polymer waterproof membranes and bitumen waterproof membranes), are easily peeled off, and cannot be firmly bonded; while the coating product prepared by the present invention has high adhesion performance to waterproof membranes and cannot be easily peeled off from the waterproof membranes.

[0074] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A water-based polyurethane waterproof coating for composite application with waterproof membranes, comprising the following raw materials in parts by weight: The composition includes: 50-250 parts polyether polyol, 10-60 parts diisocyanate, 1-10 parts modified crosslinking agent, 1-20 parts 1,4-butanediol, 2-10 parts ethylenediamine, 2-10 parts trimethylolpropane, 2-10 parts catalyst, 2-10 parts triethylamine, 30-100 parts organic solvent, 10-100 parts rutile titanium dioxide, 100-800 parts filler, 10-100 parts environmentally friendly film-forming aid, 6.6-45 parts other additives, and the balance being water. The modified crosslinking agent is prepared by means of trifunctional aziridine, tris(hydroxymethyl)aminomethane, ethylene glycol di(3-mercaptopropionate), trifluoroethyl methacrylate, 3-(2,3-epoxypropoxy)propylmethyldiethoxysilane, N,N-dimethylformamide, and p-benzenesulfonic acid, specifically including the following steps: Dissolve 10-20 parts of trifunctional aziridine and 10-20 parts of tris(hydroxymethyl)aminomethane in ethanol by weight, control the reaction temperature at 50-60℃, then add 1-10 parts of ethylene glycol di(3-mercaptopropionate), 1-10 parts of trifluoroethyl methacrylate and 1-20 parts of 3-(2,3-epoxypropoxy)propylmethyldiethoxysilane, react for 1-2 hours, raise the temperature to 70-80℃, then add 1-30 parts of N,N-dimethylformamide and 1-20 parts of p-benzenesulfonic acid, react for 2-3 hours, cool down and discharge the material; The environmentally friendly film-forming aid is at least one of sucrose fatty acid polyester, isosorbide, tributyl citrate, epoxidized linseed oil, and epoxidized fatty acid methyl ester.

2. The water-based polyurethane waterproof coating for composite application with waterproof membrane as described in claim 1, characterized in that, The polyether polyol is at least one of polypropylene glycol, polycarbonate polyol and polyester diol; The diisocyanate is toluene diisocyanate; The catalyst is at least one of dibutyltin dilaurate and stannous isooctanoate; The organic solvent is acetone; The filler is at least one of quartz powder, wollastonite powder, calcium carbonate, barium sulfate, and metakaolin.

3. The water-based polyurethane waterproof coating for composite application with waterproof membrane as described in claim 1, characterized in that, The other additives include, by weight: Dispersant 1-10 parts, defoamer 4-10 parts, pH adjuster 0.5-5 parts, preservative 1-10 parts, polyurethane rheology modifier 0.1-10 parts.

4. The water-based polyurethane waterproof coating for composite application with waterproof membrane as described in claim 3, characterized in that, The dispersant is at least one selected from polyacrylate, polyphosphate, polycarboxylate, cellulose derivative, fatty acid polyethylene glycol ester, and sodium dodecyl sulfate; The defoamer is at least one of polydimethylsiloxane, polyoxyethylene polyoxypropylene pentaerythritol ether, polyoxyethylene polyoxypropylene alcohol ether, and polyoxypropylene polyoxyethylene glycerol ether. The pH adjuster is at least one of ammonia, dimethylethanolamine, 2-amino-2-methyl-1-propanol and triethanolamine; The preservative is at least one of octylisothiazolinone, benzimidazole carbamate and ethylenebis(dithiocarbamate) ammonium; The polyurethane rheology modifier is at least one of hydrophobic group-modified ethoxy polyurethane polymer and polyurethane associative polymer.

5. A method for preparing a water-based polyurethane waterproof coating for composite application with waterproof membranes as described in any one of claims 1-4, comprising the following steps: S1. The dehydrated polyether polyol, diisocyanate and catalyst are reacted at 68~72℃ for 0.8~1.2h under nitrogen protection; S2. Cool to 48~50℃, then continue to add organic solvent, environmentally friendly film-forming aid and modified crosslinking agent and stir for at least 0.5h; S3. Heat to 68~72℃, then add 1,4-butanediol and trimethylolpropane, reflux under condensation, and react for 1.5~2.5h. S4. Cool to 23~27℃, add triethylamine, and stir for at least 0.5h; S5. Prepare a solution of ethylenediamine and add it to the reaction solution of step S4. Emulsify and disperse for at least 0.5 h, then remove the organic solvent by rotary evaporation. S6. Cool down to 30℃, add some water, stir for 3 minutes, then add rutile titanium dioxide, filler, other additives and the remaining water, and stir until well mixed.

6. The preparation method according to claim 5, characterized in that, In step S4, the stirring speed is 550~650 rpm; in step S5, the rotary evaporation temperature is 35~45℃ and the rotary evaporation time is 3.5~4.5h; in step S6, the stirring speed is 500 rpm.

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