Polymer cement waterproof coating and preparation method thereof

Abstract

The invention discloses a polymer cement waterproof coating. The coating is prepared from raw materials including a polymer cement waterproof emulsion, the emulsion is prepared by compounding a vinyl acetate-ethylene copolymer emulsion and a butadiene-styrene copolymer emulsion. According to the polymer cement waterproof coating prepared by the preparation method disclosed by the invention, the mechanical strength is improved, and the water resistance and alkali resistance are good; and the mechanical strength and elongation before and after water treatment and alkali treatment are not greatly changed.

Description

Technical Field

[0001] The present invention belongs to the technical field of waterproof coatings, and particularly relates to a polymer cement waterproof coating and a preparation method thereof. Background Art

[0002] Polymer cement waterproof coating (JS waterproof coating), as a type of two-component water-based waterproof coating, mainly uses polymer emulsion and cement as raw materials, and other additives and fillers are added at the same time. Therefore, it has the advantages of both polymer and cement, having excellent extensibility and waterproofness of polymer emulsion, as well as high strength of hydraulic cementitious materials and strong adhesion ability to wet substrates. The polymer waterproof coating has the advantages of the water hardening property and high impact resistance of cement, and also has the characteristics of the flexibility, high elasticity and waterproofness of the polymer coating film, greatly improving the service performance of buildings and people's living experience.

[0003] Chinese patent document CN 109896800A discloses a high-performance polymer cement waterproof coating and a preparation method thereof, including: liquid material: styrene-acrylate emulsion, vinyl acetate-ethylene copolymer emulsion, defoamer, antiseptic and fungicide, and water; powder material: white cement, quartz sand and water reducing agent; which can ensure good construction performance and good waterproof weather resistance.

[0004] In the polymer cement waterproof coating prepared by this prior art, it is impossible to ensure good mechanical strength in building waterproofing and building plastering, and at the same time, the mechanical strength and elongation rate are still good after water treatment and alkali treatment. Summary of the Invention

[0005] Based on the above problems, the present invention provides a polymer cement waterproof coating that can ensure good mechanical strength in building waterproofing and building plastering, and the mechanical strength and elongation rate change little before and after water treatment and alkali treatment.

[0006] On the one hand, the present invention provides a polymer cement waterproof coating, which is prepared from raw materials including a polymer cement waterproof emulsion; the emulsion is prepared by compounding a vinyl acetate-ethylene copolymer emulsion and a butadiene-styrene copolymer emulsion.

[0007] Further, the difference range of the glass transition temperature between the vinyl acetate-ethylene copolymer emulsion and the butadiene-styrene copolymer emulsion is ≥30°C.

[0008] Further, the contact angle of water droplets on the surface of the film after the emulsion is dried and formed is ≥45°.

[0009] Further, the content ratio of the vinyl acetate-ethylene copolymer emulsion to the butadiene-styrene copolymer emulsion is 90:10 - 70:30, by mass percentage.

[0010] Furthermore, the coating is also prepared from raw materials including heavy calcium carbonate and cement.

[0011] In a second aspect, the present invention provides a method for preparing the polymer cement waterproof coating of the present invention. The coating is prepared from the following raw materials in parts by mass: based on 100 parts of the polymer cement waterproof emulsion, it includes 40 - 80 parts of heavy calcium carbonate and 10 - 50 parts of cement.

[0012] Furthermore, the coating includes the following steps: preparing a polymer cement waterproof emulsion by compounding a vinyl acetate - ethylene copolymer emulsion and a butadiene - styrene copolymer emulsion, and then adding heavy calcium carbonate and cement and stirring and mixing them to obtain the coating.

[0013] In a third aspect, the present invention provides the application of the polymer cement waterproof coating of the present invention in the fields of building waterproofing and building plastering.

[0014] The present invention has the following beneficial effects: The present invention uses an emulsion obtained by compounding a vinyl acetate - ethylene copolymer emulsion and a butadiene - styrene copolymer emulsion to prepare a polymer cement waterproof coating. While its mechanical strength is good, its water resistance and alkali resistance are also good; the changes in mechanical strength and elongation rate before and after water treatment and alkali treatment are not significant.

[0015] The polymer cement waterproof coating prepared by the present invention is used in building waterproofing and building plastering to greatly improve its water resistance and alkali resistance within an acceptable cost range. Specific embodiments

[0016] The examples given are for better illustrating the content of the present invention, but the content of the present invention is not limited to the examples given. Therefore, those skilled in the art who make non - essential improvements and adjustments to the implementation solutions based on the above - mentioned invention content still fall within the protection scope of the present invention.

[0017] The detection method for the data results in the present invention is as follows: 1. The test method for the mechanical properties of the dry film of the emulsion is as follows: coating the polymer cement waterproof emulsion with a 1 - mm template frame, and naturally drying it for 120 h under the conditions of temperature (23 ± 2)°C and humidity (50 ± 2)%. Then, using a dumbbell - shaped cutter to cut it into standard specimens (6 mm × 115 mm), and using a universal testing machine (MTS Criterion, Model 43) to conduct tensile property testing with a tensile rate of 200 mm / min.

[0018] 2. The test method for the mechanical properties of polymer cement waterproof coatings is as follows: According to the Test Methods for Building Waterproof Coatings of GB / T 16777-2008 and the requirements of GB / T 23445-2009 Polymer Cement Waterproof Coatings, use a 1-mm thick template frame to apply the VAE / heavy calcium carbonate / cement slurry film 3 times. After drying for 96 h under the standard conditions of temperature (23±2)°C and humidity (50±2)%, put it into an oven and dry it at (40±2)°C for 48 h, then cure it for 4 h under the standard conditions. Use a dumbbell-shaped cutter to cut it into standard specimens (6 mm×115 mm), and the thickness of the specimens is (1.5±0.2) mm. Use a universal testing machine (MTS Criterion, Model 43) to test the tensile properties at room temperature, and the tensile rate is 200 mm / min.

[0019] 3. The test method for the mechanical properties of polymer cement waterproof coatings after heat treatment is as follows: Treat the specimens according to the regulations in GB / T 16777-2008, and the heat treatment temperature is (80±2)°C and the time is (168±1) h. After taking it out, place it in a desiccator to cool to room temperature, and test the tensile properties according to the test method for the mechanical properties of polymer cement waterproof coatings.

[0020] 4. The test method for the mechanical properties of polymer cement waterproof coatings after alkali treatment is as follows: Treat the specimens according to the regulations in GB / T 16777-2008, and the alkali immersion time is (168±1) h. After taking it out, rinse it thoroughly with water, dry it and put it into a drying oven at (80±2)°C for 18 h. After taking it out, place it in a desiccator to cool to room temperature, and use a slicing machine to punch it into dumbbell-shaped specimens, and test the tensile properties according to the test method for the mechanical properties of polymer cement waterproof coatings.

[0021] 5. The test method for the mechanical properties of polymer cement waterproof coatings after water treatment is as follows: Treat the specimens according to the regulations in GB / T 16777-2008, immerse them in water at (23±2)°C, and the alkali immersion time is (168±1) h. After taking it out, rinse it thoroughly with water, dry it and put it into a drying oven at (80±2)°C for 18 h. After taking it out, place it in a desiccator to cool to room temperature, and use a slicing machine to punch it into dumbbell-shaped specimens, and test the tensile properties according to the test method for the mechanical properties of polymer cement waterproof coatings.

[0022] 6. The rapid test method for the water and alkali resistance of the emulsion dry film is as follows: Use a 1-mm template frame to coat the JS waterproof emulsion film. After naturally drying for 120 h under the conditions of temperature (23±2)°C and humidity (50±2)%, conduct the water contact angle test. After turning on the contact angle measuring instrument, click "Sessile Drop Method Test" to initialize all the automated functions of the instrument; calibrate the instrument with a clean standard ball, install the dropper gun head, click the up and down control keys in the "Control" column to inhale the liquid (water), click the "Method" column, set the relevant test parameters, and click the test key to complete the test of the contact surface of the water droplet on the surface of the emulsion dry film.

[0023] The instrument software is used to analyze the measurement data. It is required that the difference between the maximum value and the minimum value of three tests is less than 1°, and the average value of the three tests is the contact angle of the dry film of the emulsion.

[0024] Example 1 82 parts of vinyl acetate-ethylene copolymer emulsion (glass transition temperature 9°C) and 18 parts of butadiene-styrene copolymer emulsion (glass transition temperature 42°C) are fully mixed to prepare a polymer cement waterproof emulsion; 65 parts of heavy calcium carbonate, 15 parts of cement, and 15 parts of water are added to 100 parts of the polymer cement waterproof emulsion and stirred evenly to prepare a polymer cement waterproof coating. According to the test methods for building waterproof coatings in GB / T 1677-2008 and the requirements for polymer cement waterproof coatings in GB / T 23445-2009, the dry film strength of the polymer cement waterproof emulsion is 5.4 MPa and the elongation is 656%; the mechanical strength of the polymer cement waterproof coating is 4.3 MPa and the elongation is 141%. The mechanical strength of the coating after water treatment is 4.5 MPa and the elongation is 152%. The mechanical strength of the coating after alkali treatment is 4.9 MPa and the elongation is 144%. The contact angle of water is 45°.

[0025] Example 2 Compared with Example 1, except that it is "72 parts of vinyl acetate-ethylene copolymer emulsion (glass transition temperature 9°C) and 28 parts of butadiene-styrene copolymer emulsion (glass transition temperature 42°C)", the preparation process is the same as that of Example 1. According to the test methods for building waterproof coatings in GB / T 1677-2008 and the requirements for polymer cement waterproof coatings in GB / T 23445-2009, the dry film strength of the polymer cement waterproof emulsion is 6.5 MPa and the elongation is 472%; the mechanical strength of the polymer cement waterproof coating is 5.1 MPa and the elongation is 109%. The mechanical strength of the coating after water treatment is 5.5 MPa and the elongation is 92%. The mechanical strength of the coating after alkali treatment is 5.2 MPa and the elongation is 86%. The contact angle of water is 47°.

[0026] Comparative Example 1 Compared with Example 1, except that the emulsion used is only "vinyl acetate-ethylene copolymer emulsion (glass transition temperature 9°C)", the preparation process is the same as that of Example 1. According to the test methods for building waterproof coatings in GB / T 1677-2008 and the requirements for polymer cement waterproof coatings in GB / T 23445-2009, the strength of the dry film of the polymer cement waterproof emulsion is 4.4 MPa and the elongation is 705%; the mechanical strength of the polymer cement waterproof coating is 2.5 MPa and the elongation is 186%. The mechanical strength of the coating after water treatment is 2.6 MPa and the elongation is 52%. The mechanical strength of the coating after alkali treatment is 2.8 MPa and the elongation is 42%. The contact angle of water is 36°.

[0027] Comparative Example 2 Compared with Example 1, except that the "butadiene-styrene copolymer emulsion" is changed to a glass transition temperature of 15°C, the preparation process is the same as that of Example 1. According to the test methods for building waterproof coatings in GB / T 1677-2008 and the requirements for polymer cement waterproof coatings in GB / T 23445-2009, the strength of the dry film of the polymer cement waterproof emulsion is 6.3 MPa and the elongation is 507%; the mechanical strength of the polymer cement waterproof coating is 4.9 MPa and the elongation is 118%. The mechanical strength of the coating after water treatment is 3.1 MPa and the elongation is 62%. The mechanical strength of the coating after alkali treatment is 3.2 MPa and the elongation is 57%. The contact angle of water is 43°.

[0028] Comparative Example 3 Compared with Example 1, except that the "vinyl acetate-ethylene copolymer emulsion glass transition temperature is 32°C" is used, the preparation process is the same as that of Example 1. According to the test methods for building waterproof coatings in GB / T 1677-2008 and the requirements for polymer cement waterproof coatings in GB / T 23445-2009, the strength of the dry film of the polymer cement waterproof emulsion is 7.3 MPa and the elongation is 237%; the mechanical strength of the polymer cement waterproof coating is 4.7 MPa and the elongation is 107%. The mechanical strength of the coating after water treatment is 2.0 MPa and the elongation is 58%. The mechanical strength of the coating after alkali treatment is 1.8 MPa and the elongation is 38%. The contact angle of water is 37°.

[0029] Comparative Example 4 Compared with Example 1, except that "the butadiene-styrene copolymer emulsion was changed to an acrylate emulsion with a glass transition temperature of -5°C", the preparation process was the same as that of Example 1. According to the test methods for building waterproof coatings in GB / T 1677-2008 and the requirements for polymer cement waterproof coatings in GB / T 23445-2009, the strength of the dry film of the polymer cement waterproof emulsion was 2.3 MPa and the elongation was 697%; the mechanical strength of the polymer cement waterproof coating was 1.6 MPa and the elongation was 218%. The mechanical strength of the coating after water treatment was 2.1 and the elongation was 112%. The mechanical strength of the coating after alkali treatment was 2.2 and the elongation was 107%. The contact angle of water was 42°.

[0030] From the above Examples 1-2 and Comparative Examples 1-4, it can be seen that in Examples 1-2 of the present invention, the emulsion used to prepare the polymer cement waterproof coating is obtained by compounding an ethylene-vinyl acetate copolymer emulsion and a butadiene-styrene copolymer emulsion with a glass transition temperature difference range ≥ 30°C, which is not used in Comparative Examples 1-4. Instead, an ethylene-vinyl acetate copolymer emulsion and / or other emulsions are mixed, or the ethylene-vinyl acetate copolymer emulsion and the butadiene-styrene copolymer emulsion used have a glass transition temperature difference range < 10°C. The results obtained show that the strength of the dry film of the polymer cement waterproof emulsion in Examples 1-2 ≥ 5.4 MPa and the elongation ≥ 472%; the mechanical strength of the polymer cement waterproof coating ≥ 4.3 MPa and the elongation ≥ 109%; the mechanical strength of the coating after water treatment ≥ 4.5 MPa and the elongation ≥ 92%; the mechanical strength of the coating after alkali treatment ≥ 4.9 MPa and the elongation ≥ 86%; the contact angle of water ≥ 45°; for Comparative Examples 1-4, the strength and elongation of the dry film of the polymer cement waterproof emulsion, the mechanical strength and elongation of the polymer cement waterproof coating, the mechanical strength and elongation of the coating after water treatment, and the mechanical strength and elongation of the coating after alkali treatment all have the problem of sacrificing one for the other and cannot simultaneously meet the requirements of Type II polymer cement waterproof coatings with the widest application range in GB / T 23445-2009, that is, the mechanical strength ≥ 1.8 MPa, the elongation ≥ 80%, the retention rate of the mechanical strength of the coating after water and alkali treatment ≥ 70%, and the elongation of the coating after water and alkali treatment ≥ 65%. At the same time, there is a phenomenon that the contact angle of water is all < 45°, and there is a significant decrease in the mechanical strength or elongation after water or alkali treatment, so that the requirements of Type II polymer cement waterproof coatings with the widest application range in GB / T 23445-2009 cannot be met. Thus, it can be seen that the technical solution of the means of compounding an ethylene-vinyl acetate copolymer emulsion and a butadiene-styrene copolymer emulsion with a glass transition temperature difference range ≥ 10°C can enable the prepared polymer cement waterproof coating to improve its mechanical strength while also improving the water resistance and alkali resistance of the polymer cement substrate in building waterproofing and building plastering.

[0031] In addition, it should be understood that although this specification is described in terms of embodiments, not every embodiment contains only one independent technical solution. This narrative manner of the specification is only for clarity. Those skilled in the art should regard the specification as a whole, and the technical solutions in each embodiment can also be appropriately combined to form other embodiments that can be understood by those skilled in the art.

Claims

1. A polymer cement waterproof coating, characterized in that: the coating is prepared from raw materials including a polymer cement waterproof emulsion; the emulsion is prepared by compounding a vinyl acetate-ethylene copolymer emulsion and a butadiene-styrene copolymer emulsion.

2. The polymer cement waterproof coating according to claim 1, characterized in that: the difference range of the glass transition temperatures of the vinyl acetate-ethylene copolymer emulsion and the butadiene-styrene copolymer emulsion is ≥30 °C.

3. The polymer cement waterproof coating according to claim 1 or 2, characterized in that: the contact angle of water droplets on the surface of the film after the emulsion is dried and formed is ≥45°.

4. The polymer cement waterproof coating according to any one of claims 1-3, characterized in that: the content ratio of the vinyl acetate-ethylene copolymer emulsion to the butadiene-styrene copolymer emulsion is 90:10 - 70:30, by mass percentage.

5. The polymer cement waterproof coating according to claim 4, characterized in that: the coating is also prepared from raw materials including heavy calcium carbonate and cement.

6. A method for preparing the polymer cement waterproof coating according to any one of claims 1-5, characterized in that: the coating is prepared from the following raw materials in parts by mass: based on 100 parts of the polymer cement waterproof emulsion, it includes 40-80 parts of heavy calcium carbonate and 10-50 parts of cement.

7. The method for the polymer cement waterproof coating according to claim 6, characterized in that: it includes the following steps: A polymer cement waterproof emulsion prepared by mixing a vinyl acetate-ethylene copolymer emulsion and a butadiene-styrene copolymer emulsion is prepared, and then heavy calcium carbonate and cement are added and stirred and mixed.

8. The application of the polymer cement waterproof coating according to any one of claims 1-5 in building waterproofing and building plastering.