Rod-shaped hydrophobic material, waterproof mortar and preparation method of waterproof mortar

Abstract

The preparation method comprises the following steps: uniformly mixing 21-30 parts by mass of a polyvinyl alcohol aqueous solution, 42-54 parts by mass of a silicone acrylic polymer emulsion and 10-18 parts by mass of calcium sulfate whiskers, and carrying out spray drying to obtain the rod-like hydrophobic material. When the rod-like hydrophobic material is applied to mortar, after the polyvinyl alcohol film is dissolved in water, the silicone-acrylic polymer particles gather along the surfaces of the calcium sulfate whiskers to form a hydrophobic film. The invention also discloses waterproof mortar and a preparation method thereof. The waterproof mortar is prepared from the following components in parts by mass: 32 to 45 parts of cement, 6 to 16 parts of rod-like hydrophobic substance, 40 to 50 parts of aggregate, 1.0 to 2.6 parts of rod-like early strength agent slow-release substance, 0.2 to 1.0 part of retarder and 0.1 to 0.2 part of cellulose ether. According to the invention, the rod-like hydrophobic substance and the rod-like early strength agent slow-release substance are introduced into a waterproof mortar system to achieve the purposes of water resistance, quick drying, improvement of flexural and compressive strength and improvement of construction efficiency.

Description

Technical Field

[0001] The present invention relates to the technical field of building materials, in particular to a rod-shaped hydrophobic object, waterproof mortar and a preparation method thereof. Background Art

[0002] Traditional waterproof mortars primarily achieve waterproofing through the addition of hydrophobic agents (such as silicones and stearates) or mineral admixtures (such as fly ash and silica fume). However, these agents suffer from poor compatibility with the cement matrix and are prone to migration and failure. Excessive addition can also lead to a decrease in the mortar's mechanical properties and deteriorate its workability. Therefore, the development of new, highly efficient hydrophobic materials to enhance the overall performance of waterproof mortars has become a research hotspot in the field of building materials. Summary of the Invention

[0003] In response to the above problems, one of the objects of the present invention is to provide a rod-shaped hydrophobic material and a preparation method thereof to solve the technical problem of poor compatibility between traditional hydrophobic agents and cement matrices; a second object of the present invention is to provide a waterproof mortar and a preparation method thereof, by introducing rod-shaped hydrophobic material and rod-shaped slow-release early strength agent into the waterproof mortar system to achieve the purpose of quick drying, improved flexural and compressive strength and construction efficiency.

[0004] In order to achieve the above object, the technical solution proposed by the present invention is: In a first aspect, the present invention provides a rod-shaped hydrophobic material comprising the following components, calculated by mass: 21-30 parts of a polyvinyl alcohol aqueous solution, 42-54 parts of a silicone-acrylic polymer emulsion, and 10-18 parts of calcium sulfate whiskers.

[0005] Preferably, the calcium sulfate whiskers have an average diameter of 0.6-2 μm, a length of 30-280 μm, and an aspect ratio of 33.3-150.

[0006] Preferably, the concentration of the polyvinyl alcohol aqueous solution is 14%-22%.

[0007] Preferably, the silicone-acrylic polymer emulsion is a silane-modified acrylate copolymer.

[0008] In a second aspect, the present invention provides a method for preparing the above-mentioned rod-shaped hydrophobic material, comprising the following steps: A. uniformly mix 21-30 parts by mass of a polyvinyl alcohol aqueous solution, 42-54 parts by mass of a silicone-acrylic polymer emulsion, and 10-18 parts by mass of calcium sulfate whiskers to obtain a spray solution; B. spray-drying the spray liquid to obtain a rod-shaped hydrophobic object.

[0009] Preferably, the specific process of step A is: at a rotation speed of 400-500 r / min, polyvinyl alcohol aqueous solution, silicone acrylic polymer emulsion, and calcium sulfate whiskers are added in sequence, dispersed at a rotation speed of 1200-1800 r / min, and stirred evenly to obtain a spray liquid.

[0010] Preferably, the specific process of step B is: setting the heater temperature, controlling the temperature of the spray liquid at 40-70° C., entering atomization, and controlling the drying temperature at 105-120° C. to obtain a rod-shaped hydrophobic object.

[0011] In a third aspect, the present invention provides a waterproof mortar comprising the following components, calculated by mass: 32-45 parts of cement, 6-16 parts of the above-mentioned rod-shaped hydrophobic material or 6-16 parts of the rod-shaped hydrophobic material prepared by the above-mentioned preparation method, 40-50 parts of aggregate, 1.0-2.6 parts of rod-shaped early strength agent slow-release material, 0.2-1.0 parts of retarder, and 0.1-0.2 parts of cellulose ether.

[0012] Preferably, the cement comprises, by mass, 30-40 parts of Portland cement and 2-5 parts of sulphoaluminate cement.

[0013] Preferably, the silicate cement is one or more of white cement or black cement.

[0014] Preferably, the sulphoaluminate cement is one or more of white cement or black cement.

[0015] Preferably, the aggregate is one or more of river sand and quartz sand.

[0016] Preferably, the retarder is one or more of sodium borate, sodium citrate, sodium gluconate and sodium polycarboxylate.

[0017] Preferably, the rod-shaped early strength slow-release material comprises the following raw materials by mass: 62-78 parts of attapulgite slurry, 15-20 parts of polyvinyl alcohol aqueous solution, and 1.8-2.3 parts of early strength agent. The preparation method of the rod-shaped early strength agent slow-release material comprises: a. Add attapulgite slurry and early strength agent in sequence at a speed of 800-1000 r / min, disperse at a speed of 400-500 r / min, then add polyvinyl alcohol aqueous solution and stir evenly to obtain a slow-release spray liquid; b. Spray-dry the slow-release spray liquid to obtain a rod-shaped slow-release early strength agent.

[0018] Preferably, the preparation method of the attapulgite slurry is as follows: add attapulgite to water and disperse and stir at a speed of 4000-5000r / min for 30 minutes, adjust the pH to 1-2 with 2-3mol / L hydrochloric acid, let it stand for 24h-48h, and then repeatedly filter and wash with deionized water until the filtrate pH = 7 and the concentration is 10%-14%, thereby obtaining attapulgite slurry.

[0019] In a fourth aspect, the present invention provides a method for preparing the above-mentioned waterproof mortar, comprising the following steps: S1. Pre-mixing a retarder, cellulose ether, a rod-shaped early strength agent slow-release material, and part of the cement to obtain a semi-finished product; S2. Add the remaining cement, aggregate, and rod-shaped hydrophobic material into the mixing equipment in sequence and mix them evenly; S3. Under stirring conditions, the semi-finished product to be used obtained in step S1 is put into the mixing equipment of step S2 and stirred for 10-20 minutes.

[0020] By adopting the above technical solution, the beneficial effects of the present invention are: (1) The rod-shaped hydrophobic material of the present invention absorbs polyvinyl alcohol aqueous solution and silicone-acrylic polymer emulsion through hydrogen bonding on the surface of calcium sulfate whiskers. After spray drying, the polyvinyl alcohol forms a film to fix the silicone-acrylic polymer particles on the surface of calcium sulfate whiskers. When applied to mortar, the polyvinyl alcohol film dissolves in water, and the silicone-acrylic polymer particles gather along the surface of calcium sulfate whiskers to form a hydrophobic film. The rod-shaped hydrophobic material can form a three-dimensional hydrophobic network inside the mortar through "physical overlap", thereby effectively reducing the water penetration path, while avoiding the damage of the mortar pore structure by traditional hydrophobic agents, and solving the problem of poor compatibility between traditional hydrophobic agents and cement matrix.

[0021] (2) The present invention introduces rod-shaped hydrophobic substances and rod-shaped slow-release early strength agents into the waterproof mortar system to achieve the goals of waterproofing, quick drying, improved flexural and compressive strength, and construction efficiency. The difference in the single crystal size of the rod-shaped hydrophobic substances and the rod-shaped slow-release early strength agents forms a stepped overlap, forming a three-dimensional network mechanical structure within the mortar, which has good mechanical properties. The three-dimensional hydrophobic network can reduce the water absorption rate of the waterproof mortar coating, increase the fluidity of the waterproof mortar powder, enhance the mixing ease, improve the early strength performance, and facilitate construction. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 This is the appearance of the rod-shaped hydrophobic coating after molding in an embodiment of the present invention.

[0023] Figure 2 This is the appearance of the rod-shaped early-strength sustained-release coating after molding according to an embodiment of the present invention.

[0024] Figure 3 This is the appearance of the waterproof mortar coating after molding according to an embodiment of the present invention.

[0025] Among them: 1. Rod-shaped hydrophobic material; 11. Calcium sulfate whiskers; 12. Silicon-acrylic polymer particles; 2. Rod-shaped slow-release early strength agent; 21. Attapulgite; 22. Lithium sulfate; 3. Waterproof mortar coating. DETAILED DESCRIPTION

[0026] The present invention will be further described below in conjunction with specific embodiments. It should be noted that the materials, reagents, etc. used below, unless otherwise specified, can be obtained from commercial sources or by existing known methods; the experimental methods below, unless otherwise specified, are all conventional methods.

[0027] In the embodiment of the present invention, the waterproof mortar includes the following raw materials in parts by mass:

[0028] The preparation method of the waterproof mortar of the present invention comprises the following steps: S1. Pre-mixing a retarder, cellulose ether, a rod-shaped early strength agent slow-release material, and part of the cement to obtain a semi-finished product; S2. Add the remaining cement, aggregate, and rod-shaped hydrophobic material into the mixing equipment in sequence and mix them evenly; S3. Under stirring conditions, the semi-finished product to be used obtained in step S1 is put into the mixing equipment of step S2 and stirred for 10-20 minutes to obtain waterproof mortar.

[0029] In the embodiment of the present invention, the rod-shaped hydrophobic material comprises the following raw materials in parts by mass: 10-18 parts of calcium sulfate whiskers, 21-30 parts of polyvinyl alcohol aqueous solution, and 42-54 parts of silicone-acrylic polymer emulsion.

[0030] The preparation method of the rod-shaped hydrophobic material is as follows: A. Evenly mix the polyvinyl alcohol aqueous solution, silicone-acrylic polymer emulsion and calcium sulfate whiskers to obtain a spray liquid.

[0031] Specifically, polyvinyl alcohol aqueous solution, silicone-acrylic polymer emulsion and calcium sulfate whiskers are sequentially added at a rotation speed of 400-500 r / min, dispersed at a rotation speed of 1200-1800 r / min, and stirred evenly to prepare the spray liquid.

[0032] The polyvinyl alcohol solution can be purchased directly from the market or prepared by oneself. The preparation method is as follows: adding polyvinyl alcohol to water and stirring and swelling at a speed of 400-500 r / min to obtain the polyvinyl alcohol aqueous solution.

[0033] B. Spray-dry the spray liquid to obtain a rod-shaped hydrophobic object.

[0034] Specifically, the temperature of the heater is set to control the temperature of the spray liquid at 40-70°C, and the atomization step is started. The drying temperature is controlled at 105-120°C to obtain the rod-shaped hydrophobic material.

[0035] The preparation principle of the rod-shaped hydrophobic material of the embodiment of the present invention is as follows: through the hydrogen bonding effect on the surface of calcium sulfate whiskers, polyvinyl alcohol aqueous solution and silicone-acrylic polymer emulsion are adsorbed. After spray drying, the polyvinyl alcohol forms a film to fix the silicone-acrylic polymer particles on the surface of the calcium sulfate whiskers. When applied to the mortar, after the polyvinyl alcohol film is dissolved in water, the silicone-acrylic polymer particles 22 gather along the surface of the calcium sulfate whiskers 21 to form a hydrophobic film. The appearance of the coating after forming is as follows: Figure 1 As shown in Figure 2, rod-shaped hydrophobes can form a three-dimensional hydrophobic network within the mortar through "physical overlap," effectively reducing water penetration paths while preventing traditional hydrophobic agents from damaging the mortar's pore structure. This addresses the poor compatibility of traditional hydrophobic agents with the cement matrix and their tendency to migrate and fail. Furthermore, the toughening effect of calcium sulfate whiskers can offset the negative impact of hydrophobic agents on the mortar's mechanical properties.

[0036] In the embodiment of the present invention, the rod-shaped early strength agent slow-release material includes the following raw materials in parts by mass: 62-78 parts of attapulgite slurry, 15-20 parts of polyvinyl alcohol aqueous solution, and 1.8-2.3 parts of early strength agent.

[0037] The preparation method of the rod-shaped sustained-release early-strength agent comprises: a. At a speed of 800-1000 r / min, add attapulgite slurry and early strength agent in sequence, disperse at a speed of 400-500 r / min, then add polyvinyl alcohol aqueous solution, stir evenly to obtain a slow-release spray liquid.

[0038] Among them, the preparation method of attapulgite slurry is as follows: attapulgite is added to water and dispersed and stirred at a speed of 4000-5000 r / min for 30 minutes, then the pH is adjusted to 1-2 with 2-3 mol / L hydrochloric acid, and after standing for 24h-48h, it is repeatedly filtered and washed with deionized water until the filtrate pH = 7 and the concentration is 10%-14%, thereby obtaining attapulgite slurry.

[0039] b. Spray-dry the slow-release spray liquid to obtain a rod-shaped slow-release early strength agent.

[0040] The preparation principle of the rod-shaped slow-release early strength agent of the embodiment of the present invention is as follows: first, the attapulgite 21 is soaked with dilute hydrochloric acid and then cleaned. The dilute hydrochloric acid can dissolve the soluble substances inside the attapulgite 21, so that a cavity structure appears inside. Then, the early strength agent 22 is filled into the cavity and sealed with a polyvinyl alcohol aqueous solution to form a soluble film. When applied to mortar, the effect of slowly releasing the early strength agent can be obtained after stirring with water. The appearance of the coating after forming is as follows: Figure 2 shown.

[0041] In the embodiment of the present invention, the cement comprises, by mass, 30-40 parts of Portland cement and 2-5 parts of sulphoaluminate cement.

[0042] The silicate cement is preferably one or more of white cement or black cement. The strength grade of the silicate cement is preferably one or more of 32.5 MPa, 42.5 MPa, or 52.5 MPa. The sulphoaluminate cement is one or more of white cement or black cement. The strength grade of the sulphoaluminate cement is preferably one or more of 52.5 MPa or 62.5 MPa.

[0043] In the embodiment of the present invention, the aggregate is preferably one or more of river sand and quartz sand.

[0044] In the embodiment of the present invention, the retarder is preferably one or more of sodium borate, sodium citrate, sodium gluconate and sodium polycarboxylate.

[0045] The waterproof mortar of the embodiment of the present invention has the following advantages: 1. Waterproof mortar has physical barrier and chemical hydrophobic properties, and excellent anti-osmotic pressure.

[0046] The rod-shaped composites with high aspect ratios are staggered in the mortar, extending the water penetration path and forming a physical barrier. The silane groups (-Si-O-Si-) on the surface of the rod-shaped hydrophobic compounds can reduce the interfacial energy and form a low-adhesion surface.

[0047] 2. The stepped three-dimensional structure of waterproof mortar improves shrinkage resistance, compressive strength and flexural strength.

[0048] The rod-shaped hydrophobic material and the rod-shaped accelerator slow-release material are tightly combined with the hydrated CSH gel of Portland cement and sulphoaluminate cement, which can reduce shrinkage cracks. Due to the difference in particle size, the rod-shaped hydrophobic material and the rod-shaped accelerator slow-release material form a stepped staggered three-dimensional structure. The appearance of the waterproof mortar after the 3-layer coating is formed is as follows: Figure 3 As shown, the mechanical properties are better and more stable.

[0049] 3. Slow release of early strength performance of waterproof mortar.

[0050] The early strength agent is compounded with the porous material of attapulgite, utilizing the pore structure to absorb the active components and controlling the release rate through the diffusion gradient. This provides the early strength properties of mortar while ensuring sufficient construction time.

[0051] In order to better illustrate the purpose, technical solutions and advantages of the present invention, the present invention will be further described below in conjunction with Examples 1-3 and Comparative Examples 1-2.

[0052] The sources of materials for the following Examples 1-3 and Comparative Examples 1-2 are as follows: The calcium sulfate whiskers have an average diameter of 0.6-2 μm, a length of 30-280 μm, and an aspect ratio of 33.3-150. Calcium sulfate whiskers (model: plastic grade) are produced by Sichuan Jingying New Material Technology Co., Ltd.

[0053] The concentration of the polyvinyl alcohol aqueous solution is preferably 14%-22%. The polyvinyl alcohol is PVA17-99, with a polymerization degree of 1700 and a degree of alcoholysis of 99%. Anhui Wanwei High-tech Materials Co., Ltd. is used to obtain polyvinyl alcohol 17-99.

[0054] The silicone acrylic polymer emulsion is a silane-modified acrylic ester copolymer with a glass transition temperature of -35°C to -20°C. The silicone acrylic emulsion GL-3152 is produced by Guangzhou Guanglong Chemical Technology Co., Ltd.

[0055] The average diameter of the attapulgite is 20-70 nm, the length is 0.5-5 μm, and the aspect ratio is 20-70. The attapulgite is MIN-U-GEL400, which is from Shanghai Chonghedou New Materials Co., Ltd.

[0056] Early strength agents mainly include chlorides, sulfates, carbonates and composite early strength agents. In the embodiment of the present invention, lithium sulfate is preferably used, and lithium sulfate monohydrate produced by Wuhan Jiyesheng Chemical Co., Ltd. is selected.

[0057] The silicate cement used is Jiangxi Yinshan 52.5 grade silicate white cement.

[0058] The sulphoaluminate cement used is Jiangxi Yinshan 62.5 grade sulphoaluminate white cement.

[0059] The aggregate is from Liaoning Jiahe Pengcheng Powder Technology Co., Ltd., and quartz sand of 40-80 mesh, 80-120 mesh and 200 mesh is used in combination.

[0060] The retarder is from Guangdong Longhu Technology Co., Ltd., sodium citrate and sodium polycarboxylate.

[0061] The cellulose ether used is Zhongwei's 75,000 hydroxypropyl methyl cellulose ether.

[0062] Table 1 Waterproof mortar formula of Examples 1-3 and Comparative Examples 1-2

[0063] The performance of the waterproof mortars prepared in Examples 1-3 and Comparative Examples 1-2 was tested according to the testing method in JC / T 984-2011 “Polymer Cement Waterproof Mortar”. The test results are shown in Table 2.

[0064] Table 2 Performance test results of waterproof mortars prepared in Examples 1-3 and Comparative Examples 1-2

[0065] Experiments have shown that the waterproof mortar of the embodiment is loaded with stepped rods, which has excellent resistance to osmotic pressure, improved shrinkage resistance, compressive strength and flexural strength, and while meeting the early strength performance of the mortar, ensures sufficient initial setting time, which is convenient for construction.

[0066] Compared with Example 3, the water absorption rate of Comparative Example 1 without the sustained-release hydrophobic agent and the early strength agent is significantly increased, the initial setting time and the final setting time are significantly reduced, and the waterproofness and construction operability of the mortar are deteriorated; compared with Example 3, the water absorption rate, shrinkage rate, initial setting time and final setting time of Comparative Example 2 are significantly increased and prolonged, and the compressive strength and flexural strength are reduced, that is, the waterproofness and shrinkage resistance of the mortar are deteriorated, the setting time is prolonged, and the mechanical properties are poor.

[0067] Although the present invention has been particularly shown and described in conjunction with preferred embodiments, it will be understood by those skilled in the art that various changes in form and details may be made to the present invention without departing from the spirit and scope of the invention as defined in the appended claims, and all such changes are within the scope of protection of the present invention.

Claims

1. A rod-shaped hydrophobic object, characterized in that: The invention comprises the following components in parts by mass: 21-30 parts of polyvinyl alcohol aqueous solution, 42-54 parts of silicone-acrylic polymer emulsion and 10-18 parts of calcium sulfate whiskers.

2. The rod-shaped hydrophobic object according to claim 1, characterized in that: The calcium sulfate whiskers have an average diameter of 0.6-2 μm, a length of 30-280 μm, and an aspect ratio of 33.3-150; The concentration of the polyvinyl alcohol aqueous solution is 14%-22%; The silicone-acrylic polymer emulsion is a silane-modified acrylate copolymer.

3. A method for preparing a rod-shaped hydrophobic object according to claim 1 or 2, characterized in that: The following steps are involved: A. uniformly mix 21-30 parts by mass of a polyvinyl alcohol aqueous solution, 42-54 parts by mass of a silicone-acrylic polymer emulsion, and 10-18 parts by mass of calcium sulfate whiskers to obtain a spray solution; B. spray-drying the spray liquid to obtain a rod-shaped hydrophobic object.

4. The method for preparing a rod-shaped hydrophobic object according to claim 3, wherein: The specific process of step A is as follows: adding polyvinyl alcohol aqueous solution, silicone-acrylic polymer emulsion and calcium sulfate whiskers in sequence at a rotation speed of 400-500 r / min, dispersing them at a rotation speed of 1200-1800 r / min, and stirring them evenly to obtain a spray liquid. The specific process of step B is as follows: setting the heater temperature, controlling the temperature of the spray liquid at 40-70°C, entering atomization, and controlling the drying temperature at 105-120°C to obtain a rod-shaped hydrophobic object.

5. A waterproof mortar, characterized in that: The invention comprises the following components in parts by mass: 32-45 parts of cement, 6-16 parts of the rod-shaped hydrophobic material according to claim 1 or 2 or 6-16 parts of the rod-shaped hydrophobic material prepared by the preparation method according to claim 3 or 4, 40-50 parts of aggregate, 1.0-2.6 parts of rod-shaped early strength agent slow-release material, 0.2-1.0 parts of retarder, and 0.1-0.2 parts of cellulose ether.

6. The waterproof mortar according to claim 5, characterized in that: Calculated by mass, the cement comprises: 30-40 parts of Portland cement and 2-5 parts of sulphoaluminate cement.

7. The waterproof mortar according to claim 6, characterized in that: The silicate cement is one or more of white cement or black cement; The sulphoaluminate cement is one or more of white cement and black cement; The aggregate is one or more of river sand and quartz sand; The retarder is one or more of sodium borate, sodium citrate, sodium gluconate and sodium polycarboxylate.

8. The waterproof mortar according to claim 5, characterized in that: The rod-shaped early strength slow-release material comprises the following raw materials by mass: 62-78 parts of attapulgite slurry, 15-20 parts of polyvinyl alcohol aqueous solution, and 1.8-2.3 parts of early strength agent; The preparation method of the rod-shaped sustained-release early-strength agent comprises: a. Add attapulgite slurry and early strength agent in sequence at a speed of 800-1000 r / min, disperse at a speed of 400-500 r / min, then add polyvinyl alcohol aqueous solution and stir evenly to obtain a slow-release spray liquid; b. Spray-dry the slow-release spray liquid to obtain a rod-shaped slow-release early strength agent.

9. The waterproof mortar according to claim 8, characterized in that: The preparation method of the attapulgite slurry is as follows: Add attapulgite into water and disperse and stir at a speed of 4000-5000 r / min for 30 minutes, adjust the pH to 1-2 with 2-3 mol / L hydrochloric acid, let it stand for 24h-48h, and then filter and wash it repeatedly with deionized water until the filtrate pH is 7 and the concentration is 10%-14%, thereby obtaining attapulgite slurry.

10. A method for preparing the waterproof mortar according to any one of claims 5 to 9, characterized in that: The steps include: S1. Pre-mixing a retarder, cellulose ether, a rod-shaped early strength agent slow-release material, and part of the cement to obtain a semi-finished product; S2. Add the remaining cement, aggregate, and rod-shaped hydrophobic material into the mixing equipment in sequence and mix them evenly; S3. Under stirring conditions, the semi-finished product to be used obtained in step S1 is put into the mixing equipment of step S2 and stirred for 10-20 minutes.

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