Polymer cement waterproof coating and preparation method thereof

Abstract

The application discloses a polymer cement waterproof coating, which is prepared from raw materials including a polymer cement waterproof emulsion; and the emulsion is prepared from a vinyl acetate-ethylene copolymer emulsion and a butadiene-styrene copolymer emulsion. The polymer cement waterproof coating has good water resistance and alkali resistance while improving the mechanical strength, and the mechanical strength and elongation rate change little before and after water treatment and alkali treatment.

Description

Technical Field

[0001] This invention belongs to the field of waterproof coating technology, specifically relating to a polymer cement waterproof coating and its preparation method. Background Technology

[0002] Polymer cementitious waterproof coating (JS waterproof coating), as a type of two-component water-based waterproof coating, is formulated with polymer emulsion and cement as the main raw materials, along with other additives and fillers. Therefore, it combines the advantages of both polymers and cement, possessing the excellent extensibility and waterproof properties of polymer emulsions, as well as the high strength and strong adhesion to damp substrates of hydraulic cementitious materials. Polymer waterproof coatings combine the hydraulic properties and high impact resistance of cement with the flexibility, high elasticity, and waterproof properties of polymer films, significantly improving the performance of buildings and the living experience for residents.

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

[0004] The existing technology, while failing to improve the mechanical strength of the polymer cement waterproof coating used in building waterproofing and plastering, ensures that the mechanical strength and elongation remain good after water treatment and alkali treatment. Summary of the Invention

[0005] To address the aforementioned issues, this invention provides a polymer cement waterproofing coating that ensures good mechanical strength in building waterproofing and plastering while exhibiting minimal changes in mechanical strength and elongation before and after water and alkali treatment.

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

[0007] Furthermore, the glass transition temperatures of the vinyl acetate-ethylene copolymer emulsion and the butadiene-styrene copolymer emulsion differ by a range of ≥30℃.

[0008] Furthermore, after the emulsion dries into a film, the contact angle of water droplets on the film surface is ≥45°.

[0009] Furthermore, 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 prepared from raw materials including heavy calcium carbonate and cement.

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

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

[0013] Thirdly, the present invention provides the application of the polymer cement waterproof coating described herein in the fields of building waterproofing and building plastering.

[0014] The present invention has the following beneficial effects:

[0015] This invention uses an emulsion prepared by compounding vinyl acetate-ethylene copolymer emulsion and butadiene-styrene copolymer emulsion to prepare a polymer cement waterproof coating. It has good mechanical strength, as well as good water resistance and alkali resistance; the mechanical strength and elongation do not change much before and after water treatment and alkali treatment.

[0016] The polymer cement waterproof coating prepared by this invention can significantly improve the water resistance and alkali resistance of building waterproofing and building plastering within an acceptable cost range. Detailed Implementation

[0017] The examples provided are for illustrative purposes only and are not intended to limit the scope of the invention. Therefore, non-essential modifications and adjustments made to the embodiments by those skilled in the art based on the above description are still within the protection scope of this invention.

[0018] The data result detection method in this invention is as follows:

[0019] 1. The test method for the mechanical properties of the emulsion dry film is as follows: the polymer cement waterproof emulsion is coated with a 1mm template frame and naturally dried for 120h at a temperature of (23±2)℃ and a humidity of (50±2)%. Then, it is cut into standard strips (6mm×115mm) using a dumbbell-shaped cutter and tensile properties are tested using a universal testing machine (MTS Criterion, Model 43) at a tensile rate of 200mm / min.

[0020] 2. The test method for the mechanical properties of polymer cement waterproof coating is as follows: Following the test methods for building waterproof coatings (GB / T1677-2008) and the requirements for polymer cement waterproof coatings (GB / T23445-2009), a VAE / heavy calcium carbonate / cement slurry film was prepared by applying three coats using a 1mm thick template frame. After drying for 96 hours at a temperature of (23±2)℃ and a humidity of (50±2)%, the film was placed in an oven at (40±2)℃ for 48 hours and then cured under standard conditions for 4 hours. Standard strips (6mm×115mm) were cut using a dumbbell-shaped cutter, with a strip thickness of (1.5±0.2)mm. Room temperature tensile properties were tested using a universal testing machine (MTS Criterion, Model 43) at a tensile rate of 200mm / min.

[0021] 3. The test method for the mechanical properties of polymer cement waterproof coating after heat treatment is as follows: Treat the specimens according to the national standard GB / T16777-2008, with a heat treatment temperature of (80±2)℃ and a time of (168±1)h. After removal, place them 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 coating.

[0022] 4. The test method for the mechanical properties of polymer cement waterproof coating after alkali treatment is as follows: Treat the specimens according to the national standard GB / T16777-2008, with an alkali immersion time of (168±1) h. After removal, rinse thoroughly with water, wipe dry, and place in a drying oven at (80±2)℃ for 18 h. After removal, place in a desiccator to cool to room temperature, and cut into dumbbell-shaped specimens using a slicer. Test the tensile properties according to the test method for the mechanical properties of polymer cement waterproof coating.

[0023] 5. The test method for the mechanical properties of polymer cement waterproof coating after water treatment is as follows: Treat the specimens according to the national standard GB / T16777-2008, immerse them in water at (23±2)℃ for (168±1) h. After removal, rinse thoroughly with water, dry, and place in a drying oven at (80±2)℃ for 18 h. After removal, cool to room temperature in a desiccator, cut into dumbbell-shaped specimens using a slicer, and test the tensile properties according to the test method for the mechanical properties of polymer cement waterproof coating.

[0024] 6. A rapid test method for the water and alkali resistance of the emulsion dry film is as follows: Apply the JS waterproof emulsion film using a 1mm template frame, and allow it to air dry naturally for 120 hours at a temperature of (23±2)℃ and a humidity of (50±2)%. Then, perform a water contact angle test. After turning on the contact angle measuring instrument, click "Sit-drop method test" to initialize all the instrument's automated functions; calibrate the instrument with a clean standard ball, attach the dropper nozzle, click the up and down control keys in the "Control" column to draw in liquid (water), click the "Method" column, set the relevant test parameters, and click the test button to complete the water droplet contact test on the surface of the emulsion dry film.

[0025] The measurement data was analyzed using instrument software. The difference between the maximum and minimum values ​​of the three tests was required to be less than 1°. The average value of the three tests was taken as the contact angle of the emulsion dry film.

[0026] Example 1

[0027] A polymer cement waterproof emulsion was prepared by thoroughly mixing 82 parts of vinyl acetate-ethylene copolymer emulsion (glass transition temperature 9℃) and 18 parts of butadiene-styrene copolymer emulsion (glass transition temperature 42℃). A polymer cement waterproof coating was prepared by adding 65 parts of heavy calcium carbonate, 15 parts of cement, and 15 parts of water to 100 parts of the polymer cement waterproof emulsion and stirring thoroughly. According to GB / T1677-2008 Test Methods for Building Waterproof Coatings and GB / T23445-2009 Requirements for Polymer Cement Waterproof Coatings, the dry film strength of the polymer cement waterproof emulsion was tested to be 5.4 MPa, with an elongation of 656%; the mechanical strength of the polymer cement waterproof coating was 4.3 MPa, with an elongation of 141%. After water treatment, the mechanical strength of the coating was 4.5 MPa, with an elongation of 152%. After alkali treatment, the mechanical strength of the coating was 4.9 MPa, with an elongation of 144%. The water contact angle was 45°.

[0028] Example 2

[0029] Compared with Example 1, except for 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 was the same as in Example 1. According to GB / T1677-2008 Test Methods for Building Waterproof Coatings and GB / T23445-2009 Requirements for Polymer Cement Waterproof Coatings, the dry film strength of the polymer cement waterproof emulsion was tested to be 6.5 MPa, with an elongation of 472%; the mechanical strength of the polymer cement waterproof coating was 5.1 MPa, with an elongation of 109%. After water treatment, the mechanical strength of the coating was 5.5 MPa, with an elongation of 92%. After alkali treatment, the mechanical strength of the coating was 5.2 MPa, with an elongation of 86%. The water contact angle was 47°.

[0030] Comparative Example 1

[0031] Compared with Example 1, except that the emulsion used was only "vinyl acetate-ethylene copolymer emulsion (glass transition temperature 9°C)," the preparation process was the same as in Example 1. According to GB / T1677-2008 Test Methods for Building Waterproof Coatings and GB / T23445-2009 Requirements for Polymer Cement Waterproof Coatings, the dry film strength of the polymer cement waterproof emulsion was tested to be 4.4 MPa, with an elongation of 705%; the mechanical strength of the polymer cement waterproof coating was 2.5 MPa, with an elongation of 186%. After water treatment, the mechanical strength of the coating was 2.6 MPa, with an elongation of 52%. After alkali treatment, the mechanical strength of the coating was 2.8 MPa, with an elongation of 42%. The water contact angle was 36°.

[0032] Comparative Example 2

[0033] Compared with Example 1, except that the "butadiene-styrene copolymer emulsion" was changed to have a glass transition temperature of 15°C, the preparation process was the same as in Example 1. According to GB / T1677-2008 Test Methods for Building Waterproof Coatings and GB / T23445-2009 Requirements for Polymer Cement Waterproof Coatings, the dry film strength of the polymer cement waterproof emulsion was tested to be 6.3 MPa, with an elongation of 507%; the mechanical strength of the polymer cement waterproof coating was 4.9 MPa, with an elongation of 118%. After water treatment, the mechanical strength of the coating was 3.1 MPa, with an elongation of 62%. After alkali treatment, the mechanical strength of the coating was 3.2 MPa, with an elongation of 57%. The water contact angle was 43°.

[0034] Comparative Example 3

[0035] Compared with Example 1, except for the glass transition temperature of the vinyl acetate-ethylene copolymer emulsion (32°C), the preparation process was the same as in Example 1. According to GB / T1677-2008 Test Methods for Building Waterproof Coatings and GB / T23445-2009 Requirements for Polymer Cement Waterproof Coatings, the dry film strength of the polymer cement waterproof emulsion was tested to be 7.3 MPa, with an elongation of 237%; the mechanical strength of the polymer cement waterproof coating was 4.7 MPa, with an elongation of 107%. After water treatment, the mechanical strength of the coating was 2.0 MPa, with an elongation of 58%. After alkali treatment, the mechanical strength of the coating was 1.8 MPa, with an elongation of 38%. The water contact angle was 37°.

[0036] Comparative Example 4

[0037] Compared to Example 1, the preparation process was identical except that the "butadiene-styrene copolymer emulsion was replaced with an acrylate emulsion with a glass transition temperature of -5°C". According to GB / T1677-2008 Test Methods for Building Waterproof Coatings and GB / T23445-2009 Requirements for Polymer Cement Waterproof Coatings, the dry film strength of the polymer cement waterproof emulsion was tested to be 2.3 MPa with an elongation of 697%; the mechanical strength of the polymer cement waterproof coating was 1.6 MPa with an elongation of 218%. After water treatment, the mechanical strength of the coating was 2.1 MPa with an elongation of 112%. After alkali treatment, the mechanical strength of the coating was 2.2 MPa with an elongation of 107%. The water contact angle was 42°.

[0038] As can be seen from Examples 1-2 and Comparative Examples 1-4 above, the specific method used in Examples 1-2 of the present invention to prepare polymer cement waterproof coatings is to use a mixture of vinyl acetate-ethylene copolymer emulsion and butadiene-styrene copolymer emulsion with a glass transition temperature difference of ≥30℃. However, Comparative Examples 1-4 did not use this method; instead, they used a mixture of vinyl acetate-ethylene copolymer emulsion and / or other emulsions, or used vinyl acetate-ethylene copolymer emulsion and butadiene-styrene copolymer emulsion with a glass transition temperature difference of <10℃. The results show that the dry film strength of the polymer cement waterproof emulsion in Examples 1-2 is ≥5.4MPa, and the elongation is ≥472%; the mechanical strength of the polymer cement waterproof coating is ≥4.3MPa, and the elongation is ≥109%; the mechanical strength of the coating after water treatment is ≥4.5MPa, and the elongation is ≥92%; and the mechanical strength of the coating after alkali treatment is ≥4.9MPa. The elongation is ≥86%; the water contact angle is ≥45°. Comparative Examples 1-4 show that 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 exhibit certain limitations. Therefore, they cannot simultaneously meet the requirements of GB / T23445-2009 for the most widely used Type II polymer cement waterproof coating: mechanical strength ≥1.8MPa, elongation ≥80%, mechanical strength retention rate ≥70% after water and alkali treatment, and elongation ≥65%. Furthermore, the water contact angle is <45° in all cases, and the mechanical strength or elongation decreases significantly after water or alkali treatment, thus failing to meet the requirements of GB / T23445-2009 for the most widely used Type II polymer cement waterproof coating. Therefore, it is evident that only by compounding vinyl acetate-ethylene copolymer emulsion and butadiene-styrene copolymer emulsion with a glass transition temperature difference of ≥10℃ can the resulting polymer cement waterproof coating improve its mechanical strength, as well as the water resistance and alkali resistance of the polymer cement substrate used in building waterproofing and plastering.

[0039] Furthermore, it should be understood that although this specification describes embodiments, not every embodiment contains only one independent technical solution. This narrative style is merely for clarity. Those skilled in the art should consider 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 polymer cement waterproof emulsion; its emulsion is compounded from vinyl acetate-ethylene copolymer emulsion and butadiene-styrene copolymer emulsion; the glass transition temperatures of the vinyl acetate-ethylene copolymer emulsion and the butadiene-styrene copolymer emulsion differ by a range of ≥30℃.

2. The polymer cement waterproof coating according to claim 1, characterized in that: After the emulsion dries into a film, the contact angle of water droplets on the film surface is ≥45°.

3. The polymer cement waterproof coating according to claim 1 or 2, 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.

4. The polymer cement waterproof coating according to claim 3, characterized in that: The coating is prepared from raw materials including heavy calcium carbonate and cement.

5. A method for preparing the polymer cementitious waterproof coating according to any one of claims 1-4, characterized in that: The coating is prepared from the following raw materials in parts by weight: based on 100 parts of polymer cement waterproof emulsion, it includes 40-80 parts of heavy calcium carbonate and 10-50 parts of cement.

6. The method for applying a polymer cement waterproof coating according to claim 5, characterized in that: Includes the following steps: A polymer cement waterproof emulsion is prepared by mixing vinyl acetate-ethylene copolymer emulsion and butadiene-styrene copolymer emulsion, and then adding heavy calcium carbonate and cement and stirring to obtain the final product.

7. The application of the polymer cement waterproof coating according to any one of claims 1-4 in building waterproofing and building plastering.