Polyurethane sealant and preparation method thereof

Abstract

The invention relates to the technical field of building waterproof materials, and provides a polyurethane sealant and a preparation method thereof. The polyurethane sealant is prepared from the following raw materials in parts by mass: 100 parts of polyether polyol, 30 to 50 parts of plasticizer modified asphalt, 20 to 35 parts of isocyanate, 10 to 20 parts of plasticizer, 0.05 to 0.2 part of catalyst, 0.1 to 0.5 part of antioxidant, 15 to 30 parts of filler and 1 to 4 parts of additive. Through the technical scheme, the problems of low solid content, low strength, poor elasticity and poor construction performance of the polyurethane sealant in related technologies are solved.

Description

Technical Field

[0001] The present invention relates to the technical field of building waterproof materials, and specifically, to a polyurethane sealant and a preparation method thereof. Background Art

[0002] Polyurethane sealant is a new type of sealing material developed in China in the 1980s. It is made with polyurethane as the main component and other component materials added. According to the components, it is divided into two types: one-component and two-component. The one-component is made into a urethane prepolymer and cured by the reaction of the terminal isocyanate group with moisture in the air; the two-component uses isocyanate as component A (prepolymer) and the compound containing active hydrogen as component B (curing agent), which are mixed evenly in proportion and cured at room temperature.

[0003] Due to its excellent physical properties and chemical stability, and at the same time being able to bond with various substrate materials such as plastics, concrete, and metals, polyurethane sealant is widely used in the waterproof sealing of projects such as buildings, bridges, and tunnels. However, traditional polyurethane sealants have deficiencies in compatibility with asphalt-modified waterproof materials, which limits their application in composite waterproof systems. In addition, some sealants on the market have low solid content, low strength, poor elasticity, and poor construction performance, and cannot meet the requirements of modern projects for high-performance waterproof materials. Summary of the Invention

[0004] The present invention provides a polyurethane sealant and a preparation method thereof, which solve the problems of low solid content, low strength, poor elasticity, and poor construction performance of polyurethane sealants in the related art.

[0005] The technical solution of the present invention is as follows: A polyurethane sealant, comprising the following raw materials in parts by mass: 100 parts of polyether polyol, 30 - 50 parts of plasticizer-modified asphalt, 20 - 35 parts of isocyanate, 10 - 20 parts of plasticizer, 0.05 - 0.2 parts of catalyst, 0.1 - 0.5 parts of antioxidant, 15 - 30 parts of filler, and 1 - 4 parts of auxiliary agent.

[0006] The polyether polyol in the present invention can be any one or more conventional polyether polyols in the art, for example, it can be Bluestar Dongda EP-330N.

[0007] As a further technical solution, it further comprises 2 - 5 parts of curing agent.

[0008] As a further technical solution, the curing agent comprises one of 4,4'-methylenebis(2-chloroaniline) and diethyltoluenediamine.

[0009] When 4,4'-methylenebis(2-chloroaniline) is used as the curing agent in the present invention, the curing speed is moderate, the mechanical properties of the cured product are excellent, and the heat resistance and aging resistance are good; when diethyltoluenediamine is used as the curing agent, the reaction activity is moderate, the cured product has good toughness, excellent hydrolysis resistance, low toxicity and good environmental protection performance.

[0010] As a further technical solution, the isocyanate includes MDI or TDI.

[0011] As a further technical solution, the auxiliary agent includes one or two of a sediment prevention agent and a coupling agent.

[0012] As a further technical solution, the sediment prevention agent includes fumed silica.

[0013] As a further technical solution, the coupling agent includes coupling agent KH-550.

[0014] As a further technical solution, the catalyst includes dibutyltin dilaurate.

[0015] The antioxidant in the present invention can be any one or more conventional antioxidants in the art. For example, it can be antioxidant 168, antioxidant 1010, antioxidant 1098, antioxidant 300, etc., and preferably antioxidant 1010.

[0016] As a further technical solution, the raw materials of the plasticizer-modified asphalt include asphalt and a plasticizer with a mass ratio of 1:0.1~0.5.

[0017] As a further technical solution, the preparation method of the plasticizer-modified asphalt includes the following steps: heating the asphalt to 130~150°C and then adding the plasticizer and mixing evenly to obtain the plasticizer-modified asphalt.

[0018] As a further technical solution, the filler is a filler modified with a compound containing a nitrile group and a urethane group.

[0019] In the present invention, after the filler is modified with a compound containing a nitrile group and a urethane group, the surface of the filler is coated with a compound containing a nitrile group and a urethane group, which organically modifies the surface of the filler, improves the dispersibility of the filler and the compatibility with the matrix, and improves the strength and hardness of the polyurethane sealant.

[0020] As a further technical solution, the raw materials of the filler modified with a compound containing a nitrile group and a urethane group include a compound containing a nitrile group and a urethane group and a filler with a mass ratio of 1~5:50.

[0021] As a further technical solution, the raw materials of the filler modified with the compound containing a nitrile group and a carbamate group include the compound containing a nitrile group and a carbamate group and the filler in a mass ratio of 3:50.

[0022] In the present invention, the mass ratio of the compound containing a nitrile group and a carbamate group to the filler is limited to 3:50, which further improves the strength and hardness of the polyurethane sealant.

[0023] The compound containing a nitrile group and a carbamate group in the present invention can be any compound containing a nitrile group and a carbamate group. For example, it can be one or both of Boc-L-leucinenitrile and Boc-L-4-bromophenylalaninenitrile, and preferably Boc-L-leucinenitrile.

[0024] The filler in the present invention can be any one or more conventional fillers in the art. For example, it can be one or both of calcium carbonate and silica, and preferably calcium carbonate.

[0025] As a further technical solution, the preparation method of the filler modified with the compound containing a nitrile group and a carbamate group includes the following steps: After dissolving the compound containing a nitrile group and a carbamate group, add the filler for modification and then dry to obtain the filler modified with the compound containing a nitrile group and a carbamate group.

[0026] As a further technical solution, the plasticizer includes one or both of plasticizer DOP and plasticizer DOTP.

[0027] The present invention also provides a preparation method of a polyurethane sealant, which includes the following steps: S1. After vacuum dehydrating the polyether polyol, add the plasticizer-modified asphalt and mix evenly, then add the plasticizer and continue to mix to obtain a mixture; S2. Add the filler, the auxiliary agent and the antioxidant to the mixture and mix evenly. While stirring, add the isocyanate. After adding, continue to mix and add the catalyst for reaction to obtain the polyurethane sealant.

[0028] The working principle and beneficial effects of the present invention are as follows: 1. The polyurethane sealant provided by the present invention is a high-performance polyurethane sealant with asphalt as the modification material, which has high solid content, high bonding strength, high plasticity and high elasticity, has good compatibility and affinity with most waterproof materials including asphalt-modified waterproof materials, and is suitable for various waterproof sealing occasions.

[0029] 2. The polyurethane sealant provided by the present invention has a solid content greater than 98%, reducing the emission of volatile organic compounds and meeting the environmental protection requirements. At the same time, it has excellent adhesion performance to concrete, metal, wood, asphalt modified materials, etc. Moreover, it has excellent construction performance, good thixotropy, is easy to construct and does not flow. The elongation at break can reach more than 600%, and it can adapt to the deformation of the substrate.

[0030] 3. The polyurethane sealant provided by the present invention can be used for sealing the joints of the waterproof layer. When water invades the joints, the product will gradually foam as it enters with the water, blocking the leakage path. Detailed implementation mode

[0031] Next, the technical solutions in the embodiments of the present invention will be clearly and completely described in conjunction with the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without making creative efforts fall within the scope of protection of the present invention.

[0032] The parameters of the raw materials in the following examples and comparative examples are as follows: Polyether polyol: Model Bluestar Dongda EP-330N, hydroxyl value 32.5 - 35.5mgKOH / g, water content ≤0.05%; Asphalt: 90# road petroleum asphalt; Isocyanate: Model BASF MDI-50, purity 99.6%; Nano calcium carbonate: average particle size 70 ± 5nm, specific surface area 23 ± 2m 2 / g, calcium carbonate ≥93wt%, magnesium oxide ≤0.5wt%, silicon dioxide ≤0.1wt%, iron oxide ≤0.03wt%; Fumed silica: Model AEROSIL 200; Plasticizer (DOP): purity ≥99.5%, acidity (calculated as phthalic acid) ≤2%, density (20°C) 0.982 - 0.988g / cm 3 ; The preparation methods of the following examples and comparative examples are as follows: S1. Preparation of plasticizer-modified asphalt: Heat the asphalt to 130°C, keep it in a molten state, add plasticizer DOP at a stirring speed of 50rpm and stir for 10min until uniform, then continue to stir at 130°C for 30min to obtain plasticizer-modified asphalt, and cool it to 120°C for standby. The mass ratio of asphalt to plasticizer DOP is 1:0.5; S2. Preparation of sealant: ① Heat the polyether polyol to 60°C and dehydrate it under vacuum for 1 h with a vacuum degree of -0.08 MPa until the water content drops below 0.05%. ② Raise the temperature of the dehydrated polyether polyol to 130°C, add the plasticizer-modified asphalt at 120°C, and stir at a speed of 100 rpm for 2 h for mixing. ③ Cool down to 80°C, add the plasticizer and stir for 30 min, then add the filler, anti-settling agent, coupling agent, and antioxidant, and increase the stirring speed to 200 rpm to make them evenly dispersed. ④ Cool down to 75°C, dropwise add the isocyanate under stirring conditions. After the addition is complete, raise the temperature to 82°C and stir for 2 h. ⑤ Add the catalyst and stir for 30 min, and react at 80°C for 3 h. ⑥ Defoam under vacuum conditions with a vacuum degree of -0.09 MPa for 30 min. ⑦ Under nitrogen protection, use a filling machine to fill the sealant into clean containers and seal and package.

[0033] Example 1

[0034] Example 2

[0035] Example 3

[0036] Example 4

[0037] Example 5

[0038] Example 6

[0039] Example 7

[0040] The preparation method of Boc-L-leucine nitrile-modified nano calcium carbonate is as follows: Dissolve 1 part of Boc-L-leucine nitrile in 70 parts of dimethyl sulfoxide, then add 50 parts of nano calcium carbonate and stir at 3000 rpm for 30 min, and then stir at 200 rpm for 20 min, and dry to obtain Boc-L-leucine nitrile-modified nano calcium carbonate.

[0041] Example 8 The difference from Example 7 is only that: the amount of Boc-L-leucine nitrile is 3 parts.

[0042] Example 9 The difference from Example 7 is only that: the amount of Boc-L-leucinenitrile is 5 parts.

[0043] Comparative Example 1

[0044] Performance test: Preparation method of test specimens: ① Pretreatment of finished products: Place the finished sealant products obtained in Examples 1 to 6 and Comparative Example 1 at room temperature for 1 h to ensure uniform temperature, and stir to make the surface and internal components uniform; ② Preparation of MOCA: Heat and melt MOCA at 115 °C and keep it in a liquid state for standby; ③ Mixing process: First step: Weighing and preheating of finished products Accurately weigh 100 g of the finished product and place it in a dry stirring container. Place the container on an electric hot plate at 65 °C and stir and preheat at 400 rpm for 15 min to maintain uniform heating and avoid local overheating; Second step: Addition of MOCA Weigh 2.75 g of molten MOCA (corresponding to 100 g of the finished product). Maintain the container temperature at 70 °C, add MOCA, and at the same time increase the stirring speed to 900 rpm and stir for 2 min to ensure that MOCA and the finished product are fully mixed and uniform; Third step: Add the metered defoamer (0.15 g of BASF EFKA SI 2722), add the thickener (0.4 g of BASF Attagel 50 thixotropic thickener), and continue stirring for 2 min to make it evenly dispersed; Fourth step: Vacuum degassing Transfer the mixture to a vacuum container and degas it at a vacuum degree of -0.09 MPa for 10 min. Immediately proceed to the next step after degassing is completed; Fifth step: Coating and curing Spread the degassed mixture on the coating bottom plate, scrape and level it according to the thickness requirements, and naturally cool it to room temperature; Stand still for 24 hours under specified environmental conditions; Sixth step: Product performance testing For the formed film samples, cut and prepare samples according to the regulations, and then conduct various performance determinations.

[0045] Through the above steps, samples for mechanical property testing can be prepared using the produced polyurethane water-expandable sealant finished products, and the accuracy and reliability of the test results can be ensured.

[0046] Perform the following performance tests according to the method in GB / T 19250-2013, and record the test results in Table 1.

[0047] Table 1 Performance Test Results

[0048] As can be seen from Table 1, the solid contents of the polyurethane sealants provided in Examples 1 to 6 of the present invention are all higher than 98%, meeting the requirements of high solid content and reducing VOC emissions; the tensile strength is above 1.3 MPa, having good mechanical strength; the elongation at break all exceeds 600%, with high elasticity and can adapt to the deformation of the substrate; the adhesion strength to asphalt materials is above 1.2 MPa, having excellent adhesion performance; there are no cracks at -30°C to -40°C, suitable for low-temperature environments, and also having high hardness. In addition, asphalt materials are added to the raw materials of the present invention for the purpose of providing a polyurethane sealant, so the index of each performance does not need to meet the regulations in GB / T 19250-2013.

[0049] Perform tensile strength tests on the sealants obtained in Example 2 and Examples 7 to 9, and record the test results in Table 2.

[0050] Table 2 Tensile Strength Test Results

[0051] As can be seen from Table 2, after the filler is modified with a compound containing a nitrile group and a urethane group, the strength and hardness of the polyurethane sealant can be improved.

[0052] Perform tensile strength, elongation at break and adhesion strength tests on the sealant prepared in Example 2 at different temperatures; at the same time, perform storage stability and weather resistance tests, and record the test results in Tables 3 to 5.

[0053] Table 3 Performance Test Results at Different Temperatures

[0054] Table 4 Storage Stability Test Results

[0055] Table 5 Weather Resistance Test Results

[0056] The above are only the preferred embodiments of the present invention, and are not intended to limit the present invention. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A polyurethane sealing paste, characterized in that: The invention comprises the following raw materials in parts by weight: 100 parts of polyether polyol, 30-50 parts of plasticizer-modified asphalt, 20-35 parts of isocyanate, 10-20 parts of plasticizer, 0.05-0.2 parts of catalyst, 0.1-0.5 parts of antioxidant, 15-30 parts of filler and 1-4 parts of auxiliary agent.

2. A polyurethane sealing paste according to claim 1, characterized in that: The raw materials of the plasticizer-modified asphalt include asphalt and plasticizer in a mass ratio of 1:0.1-0.

5.

3. A polyurethane sealing paste according to claim 2, characterized in that: The preparation method of the plasticizer-modified asphalt comprises the following steps: heating the asphalt to 130-150° C., adding a plasticizer and mixing evenly to obtain the plasticizer-modified asphalt.

4. The polyurethane sealing paste according to claim 1, characterized in that: The filler is a compound modified filler containing a nitrile group and a carbamate group.

5. A polyurethane sealing paste according to claim 4, characterized in that: The raw materials of the filler modified by the compound containing nitrile group and carbamate group include the compound containing nitrile group and carbamate group and the filler in a mass ratio of 1 to 5:

50.

6. A polyurethane sealing paste according to claim 5, characterized in that: The compound containing a nitrile group and a carbamate group is Boc-L-leucinenitrile.

7. The polyurethane sealing paste according to claim 5, characterized in that: The filler includes one or both of calcium carbonate and white carbon black.

8. The polyurethane sealing paste according to claim 5, characterized in that: The method for preparing the compound modified filler containing nitrile groups and carbamate groups comprises the following steps: After the compound containing nitrile group and carbamate group is dissolved, a filler is added for modification and dried to obtain a filler modified with the compound containing nitrile group and carbamate group.

9. A polyurethane sealing paste according to claim 1 or 2, characterized in that: The plasticizer includes one or both of plasticizer DOP and plasticizer DOTP.

10. The method for preparing a polyurethane sealant according to any one of claims 1 to 9, characterized in that: The following steps are involved: S1. After vacuum dehydration of the polyether polyol, add the plasticizer-modified asphalt and mix evenly, then add the plasticizer and continue mixing to obtain a mixture; S2, add filler, auxiliary agent and antioxidant to the mixture and mix evenly, add isocyanate while stirring, continue mixing after adding, add catalyst to react, and obtain polyurethane sealing paste.

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