A polyurethane waterproof coating and a preparation method thereof

Abstract

The application discloses polyurethane waterproof paint and a preparation method thereof, the polyurethane waterproof paint comprises A component and B component; the A component comprises the following components in parts by weight: polyneopentyl glycol adipate diol 40-65 parts, isoflurone diisocyanate 20-35 parts, chain extender 5-10 parts, viscosity regulator 3-8 parts, perfluorooctyl triethoxysilane 2-5 parts, zinc chloride 1-3 parts, defoaming agent 1-2 parts, solvent 5-10 parts, filler 3-5 parts and stabilizer 2-5 parts; wherein the chain extender is 1,4-butanediol and dimethylol propionic acid or 2,2-dimethylol butyric acid; the B component is an isocyanate curing agent, and the mass ratio of the B component to the polyneopentyl glycol adipate diol in the A component is 1:(5-8). The polyurethane prepolymer is grafted by carboxyl silane to form a polyfluorosilane@zinc chloride system, the system can increase the roughness of the coating surface and increase the water contact angle, and then the waterproof effect of the coating is improved.

Description

Technical Field

[0001] This invention relates to a polyurethane waterproof coating and its preparation method, belonging to the technical field of waterproof coatings and their preparation. Background Technology

[0002] Polyurethane waterproof coatings typically consist of polyurethane resin, solvents or diluents, fillers, and additives. Polyurethane resin is the main component, providing the coating's basic structure and properties. It possesses excellent weather resistance, chemical resistance, and abrasion resistance, making it a key component of waterproof coatings. Solvents or diluents are used to dilute the polyurethane resin, making it easier to apply. After application, the solvent or diluent evaporates, leaving the polyurethane resin to form a robust coating. Fillers are typically used to increase the coating's volume, improve its rheological properties, and enhance its abrasion resistance and durability. Common fillers include silica sand and powdered quartz. Additives are used to adjust the coating's properties; for example, thickeners adjust the viscosity, and antioxidants and UV absorbers improve weather resistance. Furthermore, polyurethane coatings cure at room temperature, requiring no high temperatures or special curing conditions. The coating reacts with moisture in the air to form a strong, tough polyurethane film. This curing method is relatively simple, contributing to improved construction efficiency and reduced costs.

[0003] Polyurethane waterproof coatings are commonly used for waterproofing roofs, walls, and floors of buildings. Their main applications include: roof waterproofing (applied to platforms, roofs, and ceilings to effectively prevent rainwater penetration); basement waterproofing (used to waterproof basement walls and floors to prevent groundwater seepage and dampness); water tank waterproofing (used to waterproof swimming pools, water tanks, and storage tanks to ensure leak-proof construction); pipe waterproofing (used to waterproof pipes and pipe connections to prevent leaks); and industrial facility waterproofing (used to waterproof roofs, walls, and floors of industrial facilities to protect them from moisture damage).

[0004] In the prior art, some crosslinked polyurethane materials can be effectively applied to waterproof coatings. For example, Non-Patent Literature 1 describes the synthesis and characterization of fluorinated polyurethane (FPU) films for waterproof coatings, prepared by reacting fluorinated diols with diisocyanates and polyols. The addition of the fluorinated monomer acrylate (FMA) improves the hydrophobicity and thermal stability of the film. Crosslinked films further enhance their mechanical properties and solvent resistance. The resulting films exhibit good transparency, tensile strength, and elongation at break, making them suitable for waterproof coating applications. Compared to non-crosslinked films, crosslinked films have higher thermal stability: the crosslinked network structure effectively hinders the degradation reaction of polyurethane molecular chains, resulting in higher thermal stability; the crosslinking agent can improve the film's hardness, tensile strength, and modulus, making it more resistant to deformation and damage; the crosslinked film has improved solvent resistance, making it more durable and suitable for applications involving contact with chemicals; the presence of crosslinking and a rough structure on the film surface enhances its hydrophobicity, making it more resistant to water absorption.

[0005] Non-Patent Literature 2 describes the synthesis of a series of modified waterborne polyurethanes for high-performance waterproof coatings using a self-emulsification method, such as fluorinated polyurethane (FPU), siloxane-modified waterborne polyurethane (SPU), and fluorinated siloxane polyurethane (FSPU). The structure of the waterborne polyurethane was designed from scratch, and the content of fluoroacrylate monomers (FMA) and siloxane (HO-PDMS) segments in the FSPU was adjusted to achieve high-performance waterproofing. Due to vinyl crosslinking, higher temperatures during emulsion polymerization and film formation significantly improve the hydrophobicity of the film.

[0006] However, cross-linked polyurethane materials do present some technical challenges when applied to waterproof coatings, primarily in the following two aspects: First, the cross-linking reaction reduces the coating's hydrophobicity. After the cross-linking reaction occurs in the coating, the polyurethane material forms a three-dimensional network structure, increasing the coating's hardness and abrasion resistance. However, this can also lead to a decrease in hydrophobicity. This is because the cross-linking structure makes the coating surface smoother, reducing microscopic undulations and thus lowering its hydrophobic properties. This allows water molecules to penetrate more easily, affecting the waterproofing effect. Second, poor adhesion. The adhesion between the cross-linked polyurethane material and the substrate may be insufficient, leading to coating peeling or detachment. This is because the high hardness and strength of the cross-linked polyurethane material results in uneven stress distribution between it and the soft substrate, easily causing insufficient adhesion. Furthermore, improper surface preparation and unreasonable construction techniques during coating application can also affect the adhesion between the coating and the substrate, thereby impacting the waterproofing effect.

[0007] References:

[0008] Non-patent literature 1: Yu F, Cao L, Meng Z, et al. Crosslinked waterborne polyurethane with high waterproof performance[J]. Polymer Chemistry, 2016, 7(23):3913-3922;

[0009] Non-patent literature 2: Yu F, Xu X, Lin N, et al. Structural engineering of waterborne polyurethane for high performance waterproof coatings[J]. RSC Advances, 2015, 5(89):72544-72552. Summary of the Invention

[0010] The purpose of this invention is to provide a polyurethane waterproof coating and its preparation method. By grafting carboxysilane into a polyurethane prepolymer to form a polyfluorosilane@zinc chloride system, this system can increase the surface roughness of the coating and increase the water contact angle, thereby improving the waterproof effect of the coating.

[0011] To achieve the above objectives, the technical solution adopted by the present invention is as follows:

[0012] A polyurethane waterproof coating, comprising component A and component B;

[0013] Component A comprises the following components by weight: 40-65 parts of polypentyl adipate diol, 20-35 parts of isoflurane diisocyanate, 5-10 parts of chain extender, 3-8 parts of viscosity modifier, 2-5 parts of perfluorooctyltriethoxysilane, 1-3 parts of zinc chloride, 1-2 parts of defoamer, 5-10 parts of solvent, 3-5 parts of filler, and 2-5 parts of stabilizer.

[0014] The chain extender is 1,4-butanediol and dimethylolpropionic acid or 2,2-dimethylolbutyric acid;

[0015] The B component is an isocyanate curing agent, and the mass ratio of the B component to the poly(neopentyl adipate) glycol in the A component is 1:(5-8).

[0016] Preferably, the mass ratio of 1,4-butanediol to dimethylolpropionic acid or 2,2-dimethylolbutyric acid is 2:(3-8).

[0017] Preferably, the viscosity modifier is di-n-butylamine and / or acetone.

[0018] Preferably, the solvent is ethyl acetate, and / or butyl acetate, and / or isopropanol.

[0019] Preferably, the filler comprises fumed silica and phosphorus-based flame retardant, and the mass ratio of fumed silica to phosphorus-based flame retardant is 2:(1-3).

[0020] Preferably, the stabilizer includes an antioxidant and an ultraviolet absorber, and the mass ratio of the antioxidant to the ultraviolet absorber is 3:(1-2).

[0021] The preparation method of any of the above-mentioned polyurethane waterproof coatings includes the following steps:

[0022] S1. Poly(neopentyl adipate) glycol is vacuum dried and dehydrated, then added to a reaction vessel and heated. Isoflurane diisocyanate and chain extender are then added to the reaction vessel in sequence to carry out a polymerization reaction, thereby obtaining a carboxylated polyurethane emulsion.

[0023] S2. Perfluorooctyltriethoxysilane and zinc chloride are added to the carboxylated polyurethane emulsion for polycondensation reaction to obtain polyurethane resin grafted with fluorinated polysilane and doped with zinc chloride.

[0024] S3. Mix the viscosity modifier, defoamer, solvent, filler, and stabilizer, then add the mixture to the polyurethane resin and stir to obtain component A.

[0025] Preferably, in step S1, the vacuum drying and dehydration conditions are: -0.1 to -0.05 MPa, 105-125°C, for 1-3 hours.

[0026] Preferably, in step S1, the polymerization reaction conditions are: 500-800 r / min rotation speed, 70-90℃, and reaction time of 1.5-3 h.

[0027] Preferably, in step S2, the conditions for the polycondensation reaction are: 300-500 r / min rotation speed, 60-80℃, and reaction time of 1-3 h.

[0028] The beneficial effects of this invention are as follows:

[0029] By introducing a large number of carboxyl groups onto the polyurethane prepolymer and grafting perfluorooctyltriethoxysilane onto the polyurethane prepolymer through a carboxylsilanization reaction of the carboxyl groups with perfluorooctyltriethoxysilane, and then catalytically polycondensing with zinc chloride, a polyfluorosilane@zinc chloride system is formed in the coating. This system can increase the surface roughness of the coating and increase the water contact angle, thereby improving the waterproof effect of the coating. Attached Figure Description

[0030] Figure 1 The water contact angle of the coatings obtained in Example 3, Example 2 and Comparative Example 1 is shown. Detailed Implementation

[0031] The present invention will now be described in detail with reference to the accompanying drawings and embodiments.

[0032] Example 1

[0033] The components and dosage (parts by weight) of polyurethane waterproof coating are as follows:

[0034] Poly(neopentyl adipate) glycol 55 Defoamer 1 Isoflurone diisocyanate 20 Ethyl acetate 5 Dimethylolpropionic acid 6 Fumed silica 2 1,4-Butanediol 2 Phosphorus-based flame retardants 3 di-n-butylamine 5 antioxidants 3 perfluorooctyltriethoxysilane 3 UV absorber 2 Zinc chloride 2 Isocyanate curing agent 11

[0035] The preparation method of the polyurethane waterproof coating with the above components includes the following steps:

[0036] First, poly(neopentyl adipate) glycol was dried and dehydrated at -0.1 MPa and 110 °C for 2 h, then cooled to room temperature. It was then added to a reaction vessel and stirred at 800 r / min and heated to 80 °C. Isoflurane diisocyanate, 1,4-butanediol and dimethylolpropionic acid were added to the reaction vessel in sequence and reacted for 3 h to obtain a carboxylated polyurethane emulsion.

[0037] The rotation speed was adjusted to 500 r / min, and then perfluorooctyltriethoxysilane and zinc chloride were added to the reactor and reacted at 80°C for 2 h to obtain polyurethane resin grafted with fluorinated polysilane and doped with zinc chloride.

[0038] Finally, di-n-butylamine, defoamer, ethyl acetate, fumed silica, phosphorus flame retardant, antioxidant, and ultraviolet absorber were added sequentially into the reactor and stirred for 1.5 hours to obtain component A.

[0039] Simply mix component A with the isocyanate curing agent, then coat and dry.

[0040] Example 2

[0041] The components and dosage (parts by weight) of polyurethane waterproof coating are as follows:

[0042] Poly(neopentyl adipate) glycol 60 Defoamer 1 Isoflurone diisocyanate 25 Ethyl acetate 6 Dimethylolpropionic acid 5 Fumed silica 2 1,4-Butanediol 2 Phosphorus-based flame retardants 3 di-n-butylamine 3 antioxidants 3 perfluorooctyltriethoxysilane 4 UV absorber 2 Zinc chloride 3 Isocyanate curing agent 12

[0043] The preparation method of the polyurethane waterproof coating with the above components includes the following steps:

[0044] First, poly(neopentyl adipate) glycol was dried and dehydrated at -0.1 MPa and 115 °C for 2 h, then cooled to room temperature. It was then added to a reaction vessel and stirred at 700 r / min and heated to 80 °C. Isoflurane diisocyanate, 1,4-butanediol and dimethylolpropionic acid were added to the reaction vessel in sequence and reacted for 3 h to obtain a carboxylated polyurethane emulsion.

[0045] The rotation speed was adjusted to 500 r / min, and then perfluorooctyltriethoxysilane and zinc chloride were added to the reactor and reacted at 80°C for 2 h to obtain polyurethane resin grafted with fluorinated polysilane and doped with zinc chloride.

[0046] Finally, di-n-butylamine, defoamer, ethyl acetate, fumed silica, phosphorus flame retardant, antioxidant, and ultraviolet absorber were added sequentially into the reactor and stirred for 1.5 hours to obtain component A.

[0047] Simply mix component A with the isocyanate curing agent, then coat and dry.

[0048] Example 3

[0049] The components and dosage (parts by weight) of polyurethane waterproof coating are as follows:

[0050] Poly(neopentyl adipate) glycol 65 Defoamer 1 Isoflurone diisocyanate 35 Butyl acetate 8 Dimethylolpropionic acid 7 Fumed silica 2 1,4-Butanediol 2 Phosphorus-based flame retardants 3 di-n-butylamine 5 antioxidants 3 perfluorooctyltriethoxysilane 5 UV absorber 2 Zinc chloride 3 Isocyanate curing agent 13

[0051] The preparation method of the polyurethane waterproof coating with the above components includes the following steps:

[0052] First, poly(neopentyl adipate) glycol was dried and dehydrated at -0.1 MPa and 120 °C for 2 h, then cooled to room temperature. It was then added to a reaction vessel and stirred at 800 r / min and heated to 80 °C. Isoflurane diisocyanate, 1,4-butanediol and dimethylolpropionic acid were added to the reaction vessel in sequence and reacted for 3 h to obtain a carboxylated polyurethane emulsion.

[0053] The rotation speed was adjusted to 500 r / min, and then perfluorooctyltriethoxysilane and zinc chloride were added to the reactor and reacted at 80°C for 2 h to obtain polyurethane resin grafted with fluorinated polysilane and doped with zinc chloride.

[0054] Finally, di-n-butylamine, defoamer, ethyl acetate, fumed silica, phosphorus flame retardant, antioxidant, and ultraviolet absorber were added sequentially into the reactor and stirred for 1.5 hours to obtain component A.

[0055] Simply mix component A with the isocyanate curing agent, then coat and dry.

[0056] Comparative Example 1

[0057] The difference from Example 3 is that perfluorooctyltriethoxysilane and zinc chloride were not added.

[0058] The components and dosage (parts by weight) of polyurethane waterproof coating are as follows:

[0059] Poly(neopentyl adipate) glycol 65 Butyl acetate 8 Isoflurone diisocyanate 35 Fumed silica 2 Dimethylolpropionic acid 7 Phosphorus-based flame retardants 3 1,4-Butanediol 2 antioxidants 3 di-n-butylamine 5 UV absorber 2 Defoamer 1 Isocyanate curing agent 13

[0060] The preparation method of the polyurethane waterproof coating with the above components includes the following steps:

[0061] First, poly(neopentyl adipate) glycol was dried and dehydrated at -0.1 MPa and 120 °C for 2 h, then cooled to room temperature. It was then added to a reaction vessel and stirred at 800 r / min and heated to 80 °C. Isoflurane diisocyanate, 1,4-butanediol and dimethylolpropionic acid were added to the reaction vessel in sequence and reacted for 3 h to obtain a carboxylated polyurethane emulsion.

[0062] Di-n-butylamine, defoamer, ethyl acetate, fumed silica, phosphorus flame retardant, antioxidant, and ultraviolet absorber were added sequentially into a reaction vessel and stirred for 1.5 hours to obtain component A.

[0063] Simply mix component A with the isocyanate curing agent, then coat and dry.

[0064] The polyurethane waterproof coatings from Examples 1-3 and Comparative Example 1 were sprayed onto a smooth metal plate and dried and cured (baked at 85°C for 1 hour) to form a polyurethane coating. The hydrophobicity and adhesion of the coating were tested. The contact angle of the coating was tested using a contact angle meter, and the adhesion was tested according to GB / T 9286-1988. The test results are shown in Table 1.

[0065] Table 1. Appearance and performance of the polyurethane waterproof coatings in Examples 1-3 and Comparative Example 1

[0066] Static water contact angle (°) Adhesion (Grade) Example 1 165 0 Example 2 167 0 Example 3 170 0 Comparative Example 1 132 1

[0067] From Table 1 and Figure 1 It can be seen that the static water contact angle of the coatings in Examples 1-3 is much larger than that of the coating in Comparative Example 1. This indicates that the addition of perfluorooctyltriethoxysilane and zinc chloride to the coating can significantly improve the waterproof performance of the coating. This is because perfluorooctyltriethoxysilane contains hydrophobic perfluoroalkyl groups, which, when added to polyurethane coatings, can increase the hydrophobicity of the coating surface, thereby enhancing the waterproof performance. Simultaneously, under the catalytic polycondensation effect of zinc chloride, the fluorine surface density in the coating can be increased, reducing the surface free energy of the coating and increasing the water contact angle. Furthermore, the adhesion rating of the coating shows that the addition of perfluorooctyltriethoxysilane and zinc chloride also improves the interfacial bonding force between the coating and the substrate, thus improving adhesion.

[0068] The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the principle of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A polyurethane waterproofing coating, characterized in that, The A component and the B component are included; The A component includes the following components by weight parts: polyneopentylene glycol adipate diol 40-65 parts, isoflurone diisocyanate 20-35 parts, chain extender 5-10 parts, viscosity modifier 3-8 parts, perfluoro octyl triethoxysilane 2-5 parts, zinc chloride 1-3 parts, defoaming agent 1-2 parts, solvent 5-10 parts, filler 3-5 parts, stabilizer 2-5 parts; The chain extender is 1,4-butanediol and dimethylol propionic acid or 2,2-dimethylol butyric acid; The preparation method of the polyurethane waterproof coating includes the following steps: S1, polyneopentylene glycol adipate diol is vacuum dried and dehydrated, then added to the reaction kettle and heated, then isoflurone diisocyanate and chain extender are sequentially added to the reaction kettle for polymerization to obtain a carboxylated polyurethane emulsion; S2, perfluoro octyl triethoxysilane and zinc chloride are added to the carboxylated polyurethane emulsion for condensation reaction to obtain a polyfluorosilane grafted and zinc chloride doped polyurethane resin; S3, the viscosity modifier, defoaming agent, solvent, filler and stabilizer are mixed and then added to the polyurethane resin for stirring to obtain the A component; The B component is an isocyanate curing agent, and the mass ratio of the B component to the polyneopentylene glycol adipate diol in the A component is 1:(5-8).

2. The polyurethane waterproof coating according to claim 1, characterized in that, The mass ratio of 1,4-butanediol to dimethylol propionic acid or 2,2-dimethylol butyric acid is 2:(3-8).

3. The polyurethane waterproof coating according to claim 1, characterized in that, The viscosity modifier is di-n-butylamine and / or acetone.

4. The polyurethane waterproof coating according to claim 1, characterized in that, The solvent is ethyl acetate, and / or butyl acetate, and / or isopropyl alcohol.

5. The polyurethane waterproof coating according to claim 1, characterized in that, The filler includes fumed silica and phosphorus flame retardant, and the mass ratio of fumed silica to phosphorus flame retardant is 2:(1-3).

6. The polyurethane waterproof coating according to claim 1, characterized in that, The stabilizer includes an antioxidant and an ultraviolet absorber, and the mass ratio of the antioxidant to the ultraviolet absorber is 3:(1-2).

7. The polyurethane waterproof coating according to claim 1, characterized in that, In step S1, the vacuum drying and dehydration conditions are: -0.1~-0.05MPa, 105-125℃, and dehydrating for 1-3h.

8. The polyurethane waterproof coating according to claim 1, characterized in that, In step S1, the polymerization conditions are: 500-800r / min rotation speed, 70-90℃, and reacting for 1.5-3h.

9. The polyurethane waterproof coating according to claim 1, characterized in that, In step S2, the condensation reaction conditions are: 300-500r / min rotation speed, 60-80℃, and reacting for 1-3h.

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