Coal gangue-based waterproof ceramic tile adhesive and preparation method thereof

Abstract

The application discloses a coal gangue-based waterproof ceramic tile adhesive and a preparation method thereof, and belongs to the technical field of building materials. Modified fiber material is coated with silicon dioxide, so that the modified fiber material can uniformly block the decarburized coal gangue. The silicon dioxide contained in the structure can make water molecules difficult to penetrate into the structure. When applied in a high-humidity environment, the application can avoid water intrusion to cause aging. The silicon dioxide is beneficial to hydration. The hydration can generate calcium silicate gel and ettringite. The ettringite is a needle-like substance and has swelling property, so that the ettringite can be inserted into the gel as an early reinforcement phase. Meanwhile, ettringite crystals grow along the gap to the gel matrix. The swelling effect can form a channel, so as to guide the modified fiber material to penetrate into the gel, increase the strength of the gel, indirectly anchor the silicon dioxide in the gel to avoid falling off, and improve the moisture resistance.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of building materials, and particularly relates to a coal gangue-based waterproof ceramic tile adhesive and a preparation method thereof. BACKGROUND

[0002] Coal gangue is a black gray rock with low carbon content and high hardness which coexists with coal seams in the process of coal formation. At present, the total amount of coal gangue storage in China has exceeded 4.5 billion tons, and is increasing at a rate of nearly 400 million tons per year. Among them, there are nearly 2000 large-scale coal gangue dumps, covering an area of more than 13,000 hectares, and the newly added area is increasing at a rate of 400 hectares per year. How to comprehensively utilize coal gangue solid waste resources in a large scale and in a harmless manner is an important issue for the majority of scientific and technological personnel.

[0003] The silicon and aluminum content in coal gangue accounts for more than 80%, which is a natural cementitious material raw material. Coal gangue gel material is one of the paths for the resource utilization of coal gangue solid waste. A cementitious material based on coal gangue solid waste and a preparation method thereof are disclosed in Chinese Patent No. CN117069399B. The content of free calcium oxide in the alkali activator is controlled to be 8% to 10%. A large amount of free calcium oxide as a reactant can fully react with more active SiO2 and Al2O3 in the modified coal gangue to obtain more tricalcium silicate and dicalcium silicate, thereby improving the mechanical properties of the cementitious material.

[0004] Coal gangue gel material is the core component of coal gangue ceramic tile adhesive, but in actual application, especially when the coal gangue content in the adhesive is high, the material properties of the coal gangue can cause a series of durability problems.

[0005] Specifically, coal gangue powder has a high water absorption due to a large number of microcracks and high porosity inside. When such adhesive is applied to the bonding of ceramic tiles in high-humidity environments such as boiler rooms and bathrooms, water molecules can easily penetrate into the material through the pores, causing the cementitious system to undergo hydration reaction or water absorption expansion. Under long-term wet conditions, the internal structure of the material will gradually deteriorate due to repeated dry-wet cycles, resulting in aging of the cementitious material, attenuation of the bonding strength, and other phenomena, which eventually leads to the emptying and even falling off of the ceramic tiles, seriously affecting the safety and durability of building decoration. SUMMARY

[0006] The coal gangue-based waterproof ceramic tile adhesive and the preparation method thereof, the modified fiber material is coated by using silicon dioxide, so that the modified fiber material can uniformly block the decarburized coal gangue, and the fiber-doped coal gangue compound powder is obtained, which is used as the filler of the adhesive, the silicon dioxide contained in the structure has the characteristics of high bond energy and three-dimensional network structure, so that water molecules are difficult to penetrate into the structure, and only act on the surface, so that the internal structure is not damaged, and the application in the high-humidity environment of the boiler room and the bathroom can avoid the aging caused by the invasion of water.

[0007] The object of the present application can be achieved by the following technical solutions:

[0008] A preparation method of a coal gangue-based waterproof ceramic tile adhesive comprises the following steps:

[0009] Step one: the fiber material is cleaned by anhydrous ethanol and acetone to obtain pretreated fiber material, and then the pretreated fiber material is coated by polydopamine to obtain modified fiber material.

[0010] Step two: nano-silicon dioxide is generated by a sol-gel method to fill the micro-cracks of the decarburized coal gangue powder, and the modified fiber material is used as a reinforcing phase to obtain a fiber-doped coal gangue compound powder.

[0011] Step three: the coal gangue-based full-solid waste cement, the fiber-doped coal gangue compound powder, the mildew-resistant modified vinyl acetate-ethylene copolymer, the fatty acid-based water reducing agent and the reinforcing agent are mixed to obtain the coal gangue-based waterproof ceramic tile adhesive.

[0012] Further, the amount ratio of the coal gangue-based full-solid waste cement, the fiber-doped coal gangue compound powder, the mildew-resistant modified vinyl acetate-ethylene copolymer, the fatty acid-based water reducing agent and the reinforcing agent is 20-30 parts: 50-60 parts: 4-5 parts: 3-4 parts: 1-2 parts.

[0013] Further, the reinforcing agent is any one or combination of calcium chloride, sodium aluminate, sodium carbonate, sodium formate, triethanolamine and calcium formate.

[0014] Further, the coal gangue-based full-solid waste cement is a portland cement produced by a dry process rotary kiln process at 1300 DEG C with a mass ratio of 2:0.5:0.3 of coal gangue, high-calcium tailings and quartz tailings.

[0015] Further, the specific preparation steps of the pretreated fiber material are as follows:

[0016] The fiber material with a diameter of 7-8 mu, anhydrous ethanol and acetone are added into a reaction kettle, and stirred at 20-25 DEG C and 500-600 r / min for 10-20 min, and then the fiber material is dried in a drying box at 60-80 DEG C for 1-2 h to obtain the pretreated fiber material.

[0017] Further, the ratio of the use of the fibrous material, deionized water and acetone is 15-16 g: 50-60 mL: 80-90 mL.

[0018] Further, the fibrous material is any one or more of hydroxypropyl methylcellulose, hydroxyethyl cellulose, polypropylene fiber, polyvinyl alcohol fiber, glass fiber, in any ratio combination.

[0019] Further, the specific preparation steps of the modified fibrous material are as follows:

[0020] The pretreated fibrous material and deionized water are added to the reaction kettle, stirred at 20-25℃ and 500-600r / min for 10-20min, the pH value is adjusted to 8-9 with NaOH solution, then dopamine hydrochloride powder and anhydrous ethanol are added, continue to stir in the dark for 24-26h, filter, wash the product with deionized water and anhydrous ethanol for 2-3 times respectively, vacuum drying at 60-80℃ for 1-2h, to obtain the modified fibrous material.

[0021] Further, the ratio of the use of the pretreated fibrous material, deionized water, dopamine hydrochloride powder and anhydrous ethanol is 12-14g: 20-30mL: 16-18mg: 10-12mL.

[0022] Further, the specific preparation steps of the fibrous coal gangue compound powder are as follows:

[0023] The modified fibrous material, ethanol, deionized water and ammonia water are added to the reaction kettle, stirred at 20-25℃ and 500-600r / min for 10-20min, then tetraethyl orthosilicate is added, continue to stir for 2-3h, then add decarburized coal gangue, continue to stir for 1-2h, filter, wash the product with deionized water and anhydrous ethanol for 2-3 times respectively, vacuum drying at 60-80℃ for 1-2h, to obtain the fibrous coal gangue compound powder.

[0024] Further, the ratio of the use of the modified fibrous material, ethanol, deionized water, ammonia water, tetraethyl orthosilicate and decarburized coal gangue is 1-1.5g: 90-100mL: 120-140mL: 15-16mL: 15-16mL: 80-90g.

[0025] Further, the specific preparation steps of the modified vinyl acetate-ethylene copolymer are as follows:

[0026] 4-vinyl-1,2-benzenedicarboxylic acid, dicumyl peroxide and acetone are added into a reaction kettle, stirred at 20-25 DEG C and 500-600r / min for 10-20min, then vinyl acetate-ethylene copolymer is added, heated to 170-180 DEG C, and continuously stirred for 10-20min to obtain the modified vinyl acetate-ethylene copolymer.

[0027] Further, the usage ratio of 4-vinyl-1,2-benzenedicarboxylic acid, dicumyl peroxide, acetone and vinyl acetate-ethylene copolymer is 20-25g:0.6-0.8g:80-90mL:50-60g.

[0028] Further, the specific preparation steps of the mildew-proof modified vinyl acetate-ethylene copolymer are as follows:

[0029] Polyphosphoric acid, diphenyl tetramine, isophthalic acid and the modified vinyl acetate-ethylene copolymer are added into a reaction kettle, stirred at 20-25 DEG C and 500-600r / min for 10-20min, heated to 140-150 DEG C under nitrogen atmosphere, continuously stirred for 2-3h, then heated to 200-220 DEG C, and continuously reacted for 6-7h, filtered, the product is soaked in 30-40% sodium bicarbonate solution for 24-26h, the residual acid liquid in the solution is removed, and vacuum dried at 60-80 DEG C for 1-2h to obtain the mildew-proof modified vinyl acetate-ethylene copolymer.

[0030] Further, the usage ratio of polyphosphoric acid, diphenyl tetramine, isophthalic acid and the modified vinyl acetate-ethylene copolymer is 70-80g:20-30g:22-25g:50-60g.

[0031] The beneficial effects of the present application are:

[0032] 1. The waterproof ceramic tile adhesive prepared by the present application utilizes the coating of silica on the modified fiber material, so that it can uniformly block the decarburized coal gangue, and the fiber-doped coal gangue compound powder is obtained as the filler of the adhesive, and the silica contained in the structure has high bond energy and three-dimensional network structure characteristics, so that water molecules are difficult to penetrate into the structure, and the internal structure is prevented from being damaged, and the application in the high-humidity and high-temperature environment of boiler room and bathroom can avoid the aging phenomenon caused by water intrusion.

[0033] 2.The fiber-doped coal gangue compound powder of the present application, the silicon dioxide in the structure can provide a silicon source, which is conducive to the hydration of cement, and the hydration can generate calcium silicate gel and ettringite in the gap between the coal gangue and the cement, the ettringite is a needle-like substance with swelling property, which can be inserted into the gel as an early reinforcement phase, at the same time, the needle-like ettringite crystals will grow along the gap to the gel matrix, the swelling effect can form a channel, which will lead to an increase in water absorption, but the modified fiber material will be guided to insert into the gel through the channel, reduce the pore, and increase the strength of the gel, because the surface of the modified fiber material contains silicon dioxide, the insertion indirectly anchors the silicon dioxide in the gel to avoid falling off, and further improves the moisture resistance.

[0034] 3.The modified fiber material of the present application, the dopamine molecules are self-polymerized on the surface of the fiber material, and are firmly attached to the fiber surface by relying on the hydrogen bond between the molecules, at the same time, the amino and catechol groups are introduced, which significantly improve the reactivity and affinity of the fiber surface, these groups can form hydrogen bonds with the silanol produced by the hydrolysis of tetraethyl orthosilicate, and the introduced amino groups can catalyze the hydrolysis and condensation reaction of tetraethyl orthosilicate, so that the silicon dioxide preferentially nucleates on the surface of the modified fiber material.

[0035] 4.The waterproof ceramic tile adhesive of the present application adds a mold-proof modified vinyl acetate-ethylene copolymer, so that the waterproof ceramic tile adhesive has mold-proof property, which can avoid the growth of mold in a humid environment, the mold-proof modified vinyl acetate-ethylene copolymer is essentially to introduce carboxyl sites to the surface of the vinyl acetate-ethylene copolymer by polymerizing the double bond of vinylbenzoic acid with the double bond in the vinyl acetate-ethylene copolymer, and guide the process of forming a polymer chain containing a triazole ring by condensation of dianiline and isophthalic acid through the carboxyl sites, the triazole ring has mold-proof property, and cooperates with the fiber-doped coal gangue compound powder to improve the growth of mold under humid conditions; the mold-proof modified vinyl acetate-ethylene copolymer as the core bonding component can fill into the capillary pores and micro-cracks generated by the solidification and shrinkage of cement, form a continuous sealing layer, and improve the strength of the cement solidification. DETAILED DESCRIPTION

[0036] The technical solutions in the embodiments of the present application will be described below in conjunction with the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, not all. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative labor are within the scope of protection of the present application.

[0037] Embodiment 1: A preparation method of a coal gangue-based waterproof ceramic tile adhesive, comprising the following steps:

[0038] S1: 15 g of fiber material (polyvinyl alcohol fiber) with a diameter of 7-8 μm, 50 mL of anhydrous ethanol and 80 mL of acetone were added to the reaction kettle, stirred at 20°C and 500 r / min for 10 min, the fiber material was placed in a drying oven at 60°C for 1 h to obtain pretreated fiber material; 12 g of pretreated fiber material and 20 mL of deionized water were added to the reaction kettle, stirred at 20°C and 500 r / min for 10 min, the pH value was adjusted to 8 with NaOH solution, then 16 mg of dopamine hydrochloride powder and 10 mL of anhydrous ethanol were added, and stirring was continued for 24 h in the dark, the product was filtered and washed with deionized water and anhydrous ethanol for 2 times respectively, and vacuum dried at 60°C for 1 h to obtain modified fiber material.

[0039] The fiber material was immersed in anhydrous ethanol and acetone to wash off the surface impurities to obtain pretreated fiber material, and dopamine was polymerized on the surface of the pretreated fiber material by hydrogen bonding to obtain modified fiber material.

[0040] S2: 1 g of modified fiber material, 90 mL of ethanol, 120 mL of deionized water and 15 mL of ammonia water were added to the reaction kettle, stirred at 20°C and 500 r / min for 10 min, then 15 mL of tetraethyl orthosilicate was added, and stirring was continued for 2 h, then 80 g of decarburized coal gangue with a particle size of 80-90 μm was added, and stirring was continued for 1 h, the product was filtered, washed with deionized water and anhydrous ethanol for 2 times respectively, and vacuum dried at 60°C for 1 h to obtain fiber-doped coal gangue composite powder.

[0041] The polydopamine layer contained on the surface of the modified fiber material can act as a medium to introduce amino and catechol groups, which can form hydrogen bonds with silanol produced by hydrolysis of tetraethyl orthosilicate, so that silica is deposited on the surface of the modified fiber, and then through physical adsorption and hydrogen bonding of decarburized coal gangue, fiber-doped coal gangue composite powder is obtained.

[0042] S3: 20 g of 4-vinyl-1,2-benzenedicarboxylic acid, 0.6 g of dicumyl peroxide and 80 mL of acetone were added to the reaction kettle, stirred at 20°C and 500 r / min for 10 min, then 50 g of vinyl acetate-ethylene copolymer was added, heated to 170°C, and stirring was continued for 10 min to obtain modified vinyl acetate-ethylene copolymer.

[0043] The vinyl group contained in 4-vinyl-1,2-benzenedicarboxylic acid copolymerizes with the double bond in the vinyl acetate-ethylene copolymer under the action of dicumyl peroxide to obtain modified vinyl acetate-ethylene copolymer.

[0044] S4: 70 g of polyphosphoric acid, 20 g of biphenyl tetramine, 22 g of isophthalic acid and 50 g of modified vinyl acetate-ethylene copolymer were added into a reaction kettle, stirred at 20℃ and 500 r / min for 10 min, heated to 140℃ under nitrogen atmosphere, continued to stir for 2 h, heated to 200℃, continued to react for 6 h, filtered, the product was soaked in a 30% sodium bicarbonate solution for 24 h, the residual acid solution in the solution was removed, and vacuum dried at 60℃ for 1 h to obtain the mildew-proof modified vinyl acetate-ethylene copolymer.

[0045] The polyphosphoric acid is a solvent, the double carboxyl groups contained in the modified vinyl acetate-ethylene copolymer and isophthalic acid are condensed with the double amino groups of biphenyl tetramine respectively to obtain a polymer chain containing a triazole ring, which is formed on the mildew-proof modified vinyl acetate-ethylene copolymer.

[0046] S5: 20 parts of coal gangue-based full-solid waste cement, 50 parts of fiber-doped coal gangue compound powder, 4 parts of mildew-proof modified vinyl acetate-ethylene copolymer, 3 parts of fatty acid-based water reducing agent and 1 part of reinforcing agent were added into a mixer, mixed at a speed of 24 r / min for 15 min, and after mixing, the discharging, testing, metering, sealing and packaging procedures were sequentially carried out to obtain a coal gangue-based waterproof ceramic tile adhesive.

[0047] Example 2: A preparation method of a coal gangue-based waterproof ceramic tile adhesive, comprising the following steps:

[0048] S1: 15.5 g of fiber material (polyvinyl alcohol fiber) with a diameter of 7-8 μm, 55 mL of anhydrous ethanol and 85 mL of acetone were added into a reaction kettle, stirred at 22.5℃ and 550 r / min for 15 min, the fiber material was placed in a drying oven at 70℃ for 1.5 h to obtain pretreated fiber material; 13 g of pretreated fiber material and 25 mL of deionized water were added into a reaction kettle, stirred at 22.5℃ and 550 r / min for 15 min, the pH value was adjusted to 8.5 with NaOH solution, then 17 mg of dopamine hydrochloride powder and 11 mL of anhydrous ethanol were added, and continued to stir for 25 h in the dark, filtered, the product was washed with deionized water and anhydrous ethanol for 2.5 times respectively, and vacuum dried at 70℃ for 1.5 h to obtain modified fiber material.

[0049] S2: 1.25 g of modified fiber material, 95 mL of ethanol, 130 mL of deionized water and 15.5 mL of ammonia water were added to the reaction kettle, stirred at 22.5℃ and 550 r / min for 15 min, then 15.5 mL of tetraethyl orthosilicate was added, and stirring was continued for 2.5 h, then 85 g of decarburized coal gangue with a particle size of 80-90 μm was added, and stirring was continued for 1.5 h, then the product was filtered, washed with deionized water and anhydrous ethanol for 2.5 times respectively, and vacuum dried at 70℃ for 1.5 h to obtain a fiber-doped coal gangue compound powder.

[0050] S3: 22.5 g of 4-vinyl-1,2-benzenedicarboxylic acid, 0.7 g of dicumyl peroxide and 85 mL of acetone were added to the reaction kettle, stirred at 22.5℃ and 550 r / min for 15 min, then 55 g of vinyl acetate-ethylene copolymer was added, heated to 175℃, and stirring was continued for 15 min to obtain a modified vinyl acetate-ethylene copolymer.

[0051] S4: 75 g of polyphosphoric acid, 25 g of diphenyltetramine, 23.5 g of isophthalic acid and 55 g of modified vinyl acetate-ethylene copolymer were added to the reaction kettle, stirred at 22.5℃ and 550 r / min for 15 min, heated to 145℃ under nitrogen atmosphere, and stirring was continued for 2.5 h, then heated to 210℃, and reaction was continued for 6.5 h, then filtered, the product was soaked in a 35% mass fraction sodium bicarbonate solution for 25 h, the residual acid liquid in the solution was removed, and vacuum dried at 70℃ for 1.5 h to obtain a mildew-resistant modified vinyl acetate-ethylene copolymer.

[0052] S5: 20 parts of coal gangue-based full-solid waste cement, 50 parts of fiber-doped coal gangue compound powder, 4.5 parts of mildew-resistant modified vinyl acetate-ethylene copolymer, 3.5 parts of fatty acid-based water reducing agent and 1.5 parts of reinforcing agent were added to a mixer, mixed at a speed of 25 r / min for 17.5 min, and after mixing was completed, the discharging, testing, metering, sealing and packaging procedures were sequentially performed to obtain a coal gangue-based waterproof ceramic tile adhesive.

[0053] Example 3: A preparation method of a coal gangue-based waterproof ceramic tile adhesive, comprising the following steps:

[0054] S1: 16 g of fiber material (polyvinyl alcohol fiber) with a diameter of 7-8 μm, 60 mL of anhydrous ethanol and 90 mL of acetone were added to a reaction kettle, stirred at 25°C and 600 r / min for 20 min, the fiber material was placed in a drying oven at 80°C for 2 h to obtain pretreated fiber material; 14 g of pretreated fiber material and 30 mL of deionized water were added to the reaction kettle, stirred at 25°C and 600 r / min for 20 min, the pH value was adjusted to 9 with NaOH solution, then 18 mg of dopamine hydrochloride powder and 12 mL of anhydrous ethanol were added, and stirring was continued for 26 h in the dark, the product was filtered and washed with deionized water and anhydrous ethanol for 3 times respectively, and vacuum dried at 80°C for 2 h to obtain modified fiber material.

[0055] S2: 1.5 g of modified fiber material, 100 mL of ethanol, 140 mL of deionized water and 16 mL of ammonia water were added to a reaction kettle, stirred at 25°C and 600 r / min for 20 min, then 16 mL of tetraethyl orthosilicate was added, and stirring was continued for 3 h, then 90 g of decarburized coal gangue with a particle size of 80-90 μm was added, and stirring was continued for 2 h, the product was filtered, washed with deionized water and anhydrous ethanol for 3 times respectively, and vacuum dried at 80°C for 2 h to obtain fiber-doped coal gangue compound powder.

[0056] S3: 25 g of 4-vinyl-1,2-benzenedicarboxylic acid, 0.8 g of dicumyl peroxide and 90 mL of acetone were added to a reaction kettle, stirred at 25°C and 600 r / min for 20 min, then 60 g of vinyl acetate-ethylene copolymer was added, heated to 180°C, and stirring was continued for 20 min to obtain modified vinyl acetate-ethylene copolymer.

[0057] S4: 80 g of polyphosphoric acid, 30 g of biphenyl tetramine, 25 g of isophthalic acid and 60 g of modified vinyl acetate-ethylene copolymer were added to a reaction kettle, stirred at 25°C and 600 r / min for 20 min, heated to 150°C under nitrogen atmosphere, and stirring was continued for 3 h, then heated to 220°C, and reaction was continued for 7 h, the product was soaked in 40% sodium bicarbonate solution for 26 h, the residual acid solution in the solution was removed, and vacuum dried at 80°C for 2 h to obtain mold-resistant modified vinyl acetate-ethylene copolymer.

[0058] S5: 20 parts of coal gangue-based full-solid waste cement, 50 parts of fiber-doped coal gangue compound powder, 5 parts of mold-resistant modified vinyl acetate-ethylene copolymer, 4 parts of fatty acid-based water reducing agent and 2 parts of reinforcing agent were added to a mixer, mixed at a speed of 26 r / min for 20 min, and then the discharging, testing, metering, sealing and packaging procedures were sequentially carried out to obtain a coal gangue-based waterproof ceramic tile adhesive.

[0059] Comparative Example 1: On the basis of Example 3, the fiber-doped coal gangue compounded powder in step S5 was replaced by commercially available decarburized coal gangue with a particle size of 80-90 μm, and the remaining steps were unchanged, to produce a coal gangue-based waterproof ceramic tile adhesive.

[0060] Comparative Example 2: On the basis of Example 3, the modified fiber material in step S2 was replaced by the pretreated fiber material in step S1, and the remaining steps were unchanged, to produce a coal gangue-based waterproof ceramic tile adhesive.

[0061] Comparative Example 3: On the basis of Example 3, the modified vinyl acetate-ethylene copolymer in step S4 was replaced by the raw material vinyl acetate-ethylene copolymer in step S3, and the remaining steps were unchanged, to produce a coal gangue-based waterproof ceramic tile adhesive.

[0062] In the examples and comparative examples:

[0063] The coal gangue-based full-solid waste cement is a portland cement produced by a dry process rotary kiln process at 1300°C using coal gangue, high-calcium tailings, and quartz tailings as raw materials in a mass ratio of 2:0.5:0.3; the fiber material is any one or more of hydroxypropyl methylcellulose, hydroxyethyl cellulose, polypropylene fiber, polyvinyl alcohol fiber, and glass fiber, combined in any ratio, and polyvinyl alcohol fiber is used in the above examples and comparative examples; the length of the fiber material is 4-6 mm. The reinforcing agent is any one or more of calcium chloride, sodium aluminate, sodium carbonate, sodium formate, triethanolamine, and calcium formate, combined in any ratio, and sodium formate is used in the above examples and comparative examples.

[0064] The waterproof ceramic tile adhesives produced in Examples 1-3 and Comparative Examples 1-3 were tested for performance, and cement samples were tested for 90 days of curing time according to the standards of JC / T 547-2005 "Ceramic Wall and Floor Tile Adhesive" and GB / T 17671-1999 "Cement Mortar Strength Test Method", and the results are shown in Table 1.

[0065] The mold resistance of the waterproof ceramic tile adhesives was tested according to the method of QB / T 2591-2003, and the test strain was a composite mold containing Aspergillus niger, Chaetomium globosum, Penicillium funiculosum, and Aspergillus terreus. The sample mold growth level was as follows: 0 level, no mold growth; 1 level, trace growth; mold growth coverage area ≦10%, 2 level, mold growth coverage area ≧10%, and the results are shown in Table 2.

[0066] Table 1: Performance test results of waterproof ceramic tile adhesives

[0067]

[0068] Table 2: Mold resistance test of waterproof ceramic tile adhesives

[0069]

[0070] As can be seen from Table 1 and Table 2, the tensile adhesive strength, bending strength and compressive strength of the waterproof ceramic tile adhesive prepared in Examples 1-3 are significantly better than those of the comparative examples, and the water absorption, mold growth and mold resistance grade are significantly lower than those of the comparative examples, indicating that the waterproof ceramic tile adhesive prepared in the present application has the properties of moisture and heat aging resistance and mold resistance, and has excellent strength.

[0071] In Comparative Example 1, the fiber-doped coal gangue compound powder is replaced by a commercially available decarburized coal gangue. The commercially available decarburized coal gangue itself has porosity, and the generation of ettringite in the hydration process can further increase the porosity. This process has little effect on the early strength, but the entry of water in a humid and hot environment will significantly reduce the strength, resulting in the aging and falling off of the adhesive.

[0072] In Comparative Example 2, the modified fiber material is replaced by a pretreated fiber material. The pretreated fiber material has no dopamine coating on the surface, and cannot form hydrogen bonds with the silanol of the hydrolyzed tetraethyl orthosilicate, making it difficult for silica to nucleate on the surface of the fiber. It is easy to form free particles by self-aggregation in the solution, and it cannot form a continuous coating layer. The fiber surface without dopamine modification has no active groups, and cannot induce the directional growth of ettringite. Ettringite is only randomly generated. The combination of fiber and gel only depends on physical entanglement, and is easy to be pulled out under stress. The adhesive is easy to produce microcracks due to shrinkage, further aggravating water penetration. The uneven silica coating leads to the fact that the interface gap between the fiber and the coal gangue cannot be effectively filled with ettringite, and water molecules are easy to penetrate from the gap, causing slip after tile paving, resulting in hollowing and falling off.

[0073] In Comparative Example 3, the modified vinyl acetate-ethylene copolymer is replaced by a vinyl acetate-ethylene copolymer that has not been grafted with vinyl benzoic acid. The subsequent generated triazole ring structure cannot be grafted into the structure of the vinyl acetate-ethylene copolymer, resulting in a decrease in mold resistance. The organic acid secreted by the mold in a humid environment will corrode the cement gel and the fiber, causing the adhesive structure to become crumbly. Mold erosion will destroy the three-dimensional network structure of the gel, and at the same time cause the interface between the fiber and the gel to debond.

[0074] Although the embodiments of the present application have been shown and described, it will be understood by those of ordinary skill in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the present application.

Claims

1. A method for preparing a coal gangue-based waterproof ceramic tile adhesive, characterized in that, Comprising the following steps: Step one: the fiber material is washed by anhydrous ethanol and acetone to obtain pretreated fiber material, and then coated by polydopamine to obtain modified fiber material; Step two: the microcracks of the nanosilica filled decarburized coal gangue powder are generated by sol-gel method, and the modified fiber material is used as a reinforcing phase to obtain a fiber-doped coal gangue compound powder; The specific preparation steps of the fiber-doped coal gangue compound powder are as follows: The modified fiber material, ethanol, deionized water and ammonia water are added into a reaction kettle, stirred at 20-25℃ and 500-600r / min for 10-20min, then tetraethyl orthosilicate is added, and stirring is continued for 2-3h, then decarburized coal gangue is added, and stirring is continued for 1-2h, then filtration, washing and vacuum drying are performed to obtain the fiber-doped coal gangue compound powder; The amount ratio of the modified fiber material, ethanol, deionized water, ammonia water, tetraethyl orthosilicate and decarburized coal gangue is 1-1.5g:90-100mL:120-140mL:15-16mL:15-16mL:80-90g; Step three: the coal gangue-based full solid waste cement, the fiber-doped coal gangue compound powder, the mildew-resistant modified vinyl acetate-ethylene copolymer, the fatty acid-based water reducing agent and the reinforcing agent are mixed to obtain a coal gangue-based waterproof ceramic tile adhesive.

2. The preparation method of the coal gangue-based waterproof ceramic tile adhesive according to claim 1, characterized in that, The mass ratio of the coal gangue-based full solid waste cement, the fiber-doped coal gangue compound powder, the mildew-resistant modified vinyl acetate-ethylene copolymer, the fatty acid-based water reducing agent and the reinforcing agent is 20-30:50-60:4-5:3-4:1-2.

3. The preparation method of the coal gangue-based waterproof ceramic tile adhesive according to claim 1, characterized in that, The specific preparation steps of the pretreated fiber material are as follows: The fiber material with a diameter of 7-8μm, anhydrous ethanol and acetone are added into a reaction kettle, and stirring is performed at 20-25℃ and 500-600r / min for 10-20min, then the fiber material is dried in a drying oven at 60-80℃ for 1-2h to obtain the pretreated fiber material; The amount ratio of the fiber material, anhydrous ethanol and acetone is 15-16g:50-60mL:80-90mL.

4. The preparation method of the coal gangue-based waterproof ceramic tile adhesive according to claim 1, characterized in that, The specific preparation steps of the modified fiber material are as follows: The pretreated fiber material and deionized water are added into a reaction kettle, and stirring is performed at 20-25℃ and 500-600r / min for 10-20min, then the pH value is adjusted to 8-9 by using a NaOH solution, then dopamine hydrochloride powder and anhydrous ethanol are added, and stirring is continued for 24-26h in the dark, then filtration, washing and vacuum drying are performed to obtain the modified fiber material.

5. The preparation method of a coal gangue-based waterproof ceramic tile adhesive according to claim 4, characterized in that, The amount ratio of the pretreated fiber material, deionized water, dopamine hydrochloride powder and anhydrous ethanol is 12-14g:20-30mL:16-18mg:10-12mL.

6. The preparation method of a coal gangue-based waterproof ceramic tile adhesive according to claim 1, characterized in that, The specific preparation steps of the mildew-resistant modified vinyl acetate-ethylene copolymer are as follows: Polyphosphoric acid, diphenyl tetramine, isophthalic acid and modified vinyl acetate-ethylene copolymer were added into a reaction kettle, stirred at 20-25℃ and 500-600r / min for 10-20min, heated to 140-150℃ under nitrogen atmosphere, continued to stir for 2-3h, then heated to 200-220℃, continued to react for 6-7h, filtered, the product was soaked in 30-40wt% sodium bicarbonate solution for 24-26h, removed the residual acid solution in the solution, vacuum dried to obtain the mildew-proof modified vinyl acetate-ethylene copolymer.

7. The preparation method of the coal gangue-based waterproof ceramic tile adhesive according to claim 6, characterized in that, The modified vinyl acetate-ethylene copolymer was prepared according to the following steps: 4-Vinyl-1,2-benzenedicarboxylic acid, dicumyl peroxide and acetone were added into a reaction kettle, stirred at 20-25℃ and 500-600r / min for 10-20min, then vinyl acetate-ethylene copolymer was added, heated to 170-180℃, continued to stir for 10-20min to obtain the modified vinyl acetate-ethylene copolymer; The amount ratio of 4-vinyl-1,2-benzenedicarboxylic acid, dicumyl peroxide, acetone and vinyl acetate-ethylene copolymer was 20-25g:0.6-0.8g:80-90mL:50-60g.

8. The preparation method of a coal gangue-based waterproof ceramic tile adhesive according to claim 6, characterized in that, The amount ratio of polyphosphoric acid, diphenyl tetramine, isophthalic acid and modified vinyl acetate-ethylene copolymer was 70-80g:20-30g:22-25g:50-60g.

9. A coal gangue-based waterproof ceramic tile adhesive, characterized in that, The modified vinyl acetate-ethylene copolymer was prepared by the method of any one of claims 1-8.

Images