Temperature-inhibiting anti-crack concrete waterproofing agent and preparation method thereof

Abstract

The invention provides a temperature-inhibiting anti-crack concrete waterproofing agent and a preparation method thereof, and is characterized in that the raw materials comprise siloxane dihydric alcohol, dihydroxy acid, diisocyanate, a catalyst, a diacylhydrazone chain extender and water; the molar ratio of the diisocyanate to the siloxane dihydric alcohol to the dihydroxy acid to the diacylhydrazone chain extender is (1.98 to 2.05) to (0.2 to 0.8) to (0.2 to 0.8) to (1.05 to 1.2); the solid content of the waterproof agent is 20%-35%; the structure of the diacylhydrazone chain extender contains carbon-carbon double bonds, disulfide bonds and acylhydrazone bond self-repairing groups. The concrete waterproof agent provided by the invention has excellent temperature control, anti-cracking and waterproof effects, is applied to concrete or other building materials, and can form a continuous and compact waterproof film on the surface of the concrete to effectively prevent water permeation; the concrete is endowed with good flexibility, crack resistance and temperature buffering effect, meanwhile, the cohesion and strength of the concrete can be increased through interaction, and the concrete can be applied to large engineering concrete and can meet the building fields of underground engineering, hydraulic structures and the like with high waterproof requirements.

Description

Technical Field

[0001] The invention belongs to the field of building material concrete admixtures, and in particular relates to a temperature-suppressing anti-cracking concrete waterproofing agent and a preparation method thereof. Background Art

[0002] Concrete is a non-homogeneous material that is brittle and prone to cracking. At the same time, its own characteristics of cement hydration heat release and shrinkage create conditions for leakage problems in structures. Relevant studies have shown that temperature cracks and the volume shrinkage of cement itself during hydration are the main reasons for cracks in current concrete structures. Since concrete is put into the mold, the cementitious material hydrates and releases heat, and after experiencing a temperature rise stage and reaching a temperature peak, it enters a temperature drop shrinkage and drying shrinkage stage until it drops to ambient temperature. Concrete itself has poor thermal conductivity. Therefore, in large-volume concrete, a temperature gradient with high internal temperature and low surface temperature often occurs, forming tensile stress on the concrete surface, causing deformation and cracking at an early age. Therefore, in order to avoid the impact of concrete cracking and penetration problems on the stability and durability of building structures, waterproofing is very important.

[0003] In large-volume, high-grade, and strongly constrained concrete projects, there are two types of waterproofing treatments for concrete building structures. One is to coat or lay a waterproof layer on the surface to block erosion, but the service life is short and the later repair projects are frequent; the other is to add waterproofing agents to concrete, which can compensate for shrinkage and tension steel bars to produce prestress and fully fill cement gaps during the cement coagulation and hardening process. Among the waterproofing agents currently used, inorganic waterproofing agents include chloride salts, sulfates, and water glass; organic waterproofing agents include fatty acid metal salts and synthetic resins. The addition of the above waterproofing agents to concrete will have a great impact on the performance of concrete, such as: chloride ions will accelerate the corrosion of steel bars in concrete, and sulfate ions will corrode the concrete matrix. Therefore, the waterproofing methods and waterproofing agents currently used have certain defects. Therefore, seeking a new waterproofing material that can comprehensively improve the waterproofness of concrete structures and reduce the risk of concrete cracking from the aspect of temperature suppression is an urgent need for the development of the construction industry. Summary of the invention

[0004] In order to solve the above problems, the present invention provides a temperature-suppressing anti-cracking concrete waterproofing agent and a preparation method thereof.

[0005] The invention relates to a temperature-suppressing anti-cracking concrete waterproofing agent, the raw materials of which include siloxane diol, dihydroxy acid, diisocyanate, catalyst, diacylhydrazone chain extender and water; the molar ratio of diisocyanate, siloxane diol, dihydroxy acid and diacylhydrazone chain extender is (1.98-2.05):(0.2-0.8):(0.2-0.8):(1.05-1.2); the solid content of the waterproofing agent is 20%-35%;

[0006] The diacylhydrazone chain extender is synthesized by the following steps:

[0007] 1) dithiol hydrocarbon and disulfur dichloride undergo exchange reaction to generate intermediate 1;

[0008] 2) Intermediate 1 undergoes substitution reaction with hydroxy enal to generate intermediate 2;

[0009] 3) The intermediate 2 is reacted with alkanedioic acid dihydrazide by Schiff base reaction to obtain a diacylhydrazone chain extender.

[0010] Furthermore, the conditions of step 1) are as follows: dithiol hydrocarbon and disulfur dichloride are reacted in a 1,4-dioxane medium with N-bromosuccinimide as a catalyst under sealed stirring for 2 to 4 hours; after the reaction is completed, the reaction mixture is concentrated in vacuo and then purified by silica gel chromatography to obtain intermediate 1.

[0011] The molar ratio of the dithiol hydrocarbon, disulfur dichloride and N-bromosuccinimide is 1:(3.9-4.2):(1.0-1.2); the dithiol hydrocarbon is a C1-C5 aliphatic hydrocarbon containing two terminal thiols, thiane, benzene, biphenyl, naphthalene, diphenyl ether, and diphenyl sulfide.

[0012] Furthermore, the conditions of step 2) are as follows: in a nitrogen atmosphere, the intermediate 1 and the hydroxy olefin aldehyde are stirred in a dichloromethane or ethyl acetate or anhydrous ethanol or acetone medium with triethylamine as an acid-binding agent in an ice bath at -5 to 5°C for 2 to 3 hours and in a water bath at 40 to 50°C for 6 to 12 hours; after the reaction is completed, the mixture is filtered, washed with saturated brine, acetone is removed by vacuum rotary evaporation, and the mixture is concentrated and recrystallized to obtain the intermediate 2.

[0013] The molar ratio of the hydroxyalkenal, intermediate 1 and triethylamine is 1:(1.1-1.5):(0.99-1.20); the hydroxyalkenal is an aldehyde compound containing at least one hydroxyl group and one carbon-carbon double bond.

[0014] Further, the conditions of step 3) are as follows: in anhydrous benzene, toluene or ethanol medium, intermediate 2 and alkanedioic acid dihydrazide are heated to reflux in an oil bath at 50-60°C with acetic acid as a catalyst for 6-9h; after the reaction, filter with a Buchner funnel, remove the solvent from the filtrate by rotary evaporation, concentrate to obtain the product, seal and fill with argon and store at low temperature. The molar ratio of intermediate 2, alkanedioic acid dihydrazide and acetic acid is 1:(2-2.2):(0.8-1.0); the alkanedioic acid dihydrazide is selected from one or more of C3-C12 aliphatic hydrocarbon dihydrazide, phthalic acid dihydrazide, isophthalic acid dihydrazide and terephthalic acid dihydrazide.

[0015] Furthermore, the siloxane diol is a siloxane substance containing two hydroxyl groups at the same time; representative examples include 1,3-bis(3-hydroxypropyl)-1,1,3,3-tetramethyldisiloxane, (1,1,3,3-tetramethyl-1,3-disiloxanediyl) dimethanol, 3-[bis(2-hydroxyethyl)amino]propane-triethoxysilane, α-[3-[1,3,3,3-tetramethyl-1-(trimethylsilyl-oxy)disiloxane]-propyl-ω-hydroxypolyoxyethylene), bis-hydroxyethoxypropyl-terminated polydimethylsiloxane.

[0016] The dihydroxy acid is a monocarboxylic acid or a dicarboxylic acid containing two hydroxyl groups; representative examples include: 2,2-dihydroxymethylpropionic acid, 2,2-dihydroxymethylbutyric acid, 3,4-dihydroxybutyric acid, ketomalonic acid, glyceric acid, tartaric acid, dihydroxybenzoic acid, dihydroxyphenylacetic acid, 3,5-dihydroxy-4-methylbenzoic acid, 4,6-dihydroxyisophthalic acid, caffeic acid, 2,4-dihydroxycinnamic acid, and 3,4-dihydroxycinnamic acid.

[0017] Furthermore, the catalyst is added in an amount of 0.5% to 1.2% of the total mass of the system, and is selected from one or more of dibutyltin dilaurate (DBTDL), trihexamethylenediamine (TEDA), N-alkyldiamine, N-alkylmorpholine, stannous octoate, zinc-bismuth composite catalyst, bismuth isooctanoate, organic zinc and zinc neodecanoate.

[0018] Furthermore, the diisocyanate is one of 4-toluene diisocyanate, trans-1,4-cyclohexyl diisocyanate, 2,6-toluene diisocyanate, 4,4'-diphenylmethane diisocyanate, dicyclohexylmethane-4,4-diisocyanate, isophorone diisocyanate, 1,6-hexamethylene diisocyanate, and lysine diisocyanate.

[0019] On the other hand, the present invention provides a method for preparing a temperature-suppressing anti-cracking concrete waterproofing agent, comprising the following steps:

[0020] The dihydroxy acid and the siloxane diol are pretreated by vacuum dehydration and drying at 120°C; then, under a nitrogen atmosphere, the dihydroxy acid and the siloxane diol are added to a four-necked flask equipped with a mechanical stirring device, a reflux condenser, a thermometer and a constant pressure dropping funnel, and stirred and mixed at room temperature; the temperature is gradually raised to 60-70°C, and a diisocyanate and a catalyst mixture are added dropwise under a stirring condition of 500-700rpm; after the addition is completed, stirring is continued at 60-70°C for 1-2h; an aprotic solvent is added to adjust the viscosity of the system, and the temperature is raised to 90-120°C and stirred at a constant temperature for 5-9h; the temperature of the system is lowered to 40-60°C, a diacylhydrazone chain extender is added, and the temperature is stirred at a constant temperature for 3-4h; a neutralizer is added until the pH of the system is 7.0-7.5 and stirred for 30min, and deionized water is added and stirred at a high speed of 1000-1500rpm for 30min for emulsification and dispersion; the residual aprotic solvent is removed by rotary evaporation to obtain a polyurethane emulsion waterproofing agent.

[0021] Furthermore, the aprotic solvent is one or more of butanone, dioxane, dimethylformamide, benzene, and toluene; and the neutralizing agent is one of NH4OH, NaOH, monoethylamine, diethylamine, triethylamine, and triethanolamine.

[0022] The present invention also provides application of the temperature-suppressing anti-cracking concrete waterproofing agent in preparing concrete.

[0023] Compared with the prior art, the present invention has the following beneficial effects:

[0024] In terms of anti-crack self-repair ability, the temperature-suppressing and anti-crack concrete waterproofing agent provided by the present technical solution has high symmetry and good three-dimensional regularity, and is easy to arrange to form a highly ordered structure; its polymer structure contains dynamic groups such as carbon-carbon double bonds, disulfide bonds and acylhydrazone bonds, which make the molecular chain further show good elasticity and flexibility; when tiny cracks appear in the material, it can participate in a reversible dynamic covalent bond reaction, so that the molecular chain segments can be rearranged and combined to self-repair the cracks or damage.

[0025] In terms of temperature suppression effect, in concrete waterproofing agents, disulfide bonds and acylhydrazone bond groups have energy absorption characteristics. The reverse fracture or dissociation process when the temperature rises can absorb heat in the environment, play a role in buffering temperature, and avoid stress concentration caused by temperature changes. In addition, they can form hydrogen bonds with cement hydration products and minerals in concrete, thereby increasing the cohesion of concrete and making the material structure more stable when the temperature changes. Carbon-carbon double bonds can undergo cross-linking reactions at high temperatures to form a tight three-dimensional network structure, restrict the movement of molecular chains, and thus reduce the heat accumulation caused by the intensified movement of molecular chains.

[0026] In terms of waterproofing ability, the concrete waterproofing agent provided by the present invention can form a continuous and dense waterproof film on the surface of concrete or other building materials, effectively preventing water penetration. During the drying and film-forming process of the waterproofing agent, the acylhydrazone bond, disulfide bond and silylmethyl group can form a composite waterproof system with the concrete raw materials through chemical bonding; the presence of double bonds can adjust the flexibility and hardness of the polymer, better adapt to the deformation of the base material, and maintain the integrity of the waterproof film.

[0027] The whole preparation route from the synthesis of the diacylhydrazone chain extender to the concrete waterproofing agent is simple and easy to operate, with mild reaction and abundant raw materials. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1 Preparation process of diacylhydrazone chain extender 1 in Preparation Example 1.

[0029] Figure 2 Preparation process of diacylhydrazone chain extender 2 in Preparation Example 2.

[0030] Figure 3 Preparation process of diacylhydrazone chain extender 3 in Preparation Example 3.

[0031] Figure 4 H NMR spectrum of the diacylhydrazone chain extender 1 obtained in Preparation Example 1.

[0032] Figure 5 H NMR spectrum of diacylhydrazone chain extender 2 obtained in Preparation Example 2.

[0033] Figure 6 H NMR spectrum of diacylhydrazone chain extender 3 obtained in Preparation Example 3. DETAILED DESCRIPTION

[0034] The technical solution of the present invention is further described in detail below in conjunction with several preferred embodiments and the accompanying drawings. This embodiment is implemented on the premise of the technical solution of the invention, and a detailed implementation method and a specific operation process are given, but the protection scope of the present invention is not limited to the following embodiments. The contents not described in detail in the specification of the present invention belong to the known technology of professional and technical personnel in this field.

[0035] Unless otherwise defined, the experimental materials used in the following examples and comparative examples can be purchased from conventional biochemical reagent companies.

[0036] Preparation Example 1

[0037] according to Figure 1 The process shown is to synthesize the diacylhydrazone chain extender 1:

[0038] 1) In a 100 mL reaction tube, add 0.02 mol of ethylene glycol dimercaptoacetate and 0.02 mol of N-bromosuccinimide (C4H4BrNO2, abbreviated as NBS) dissolved in 64 mL of 1,4-dioxane, add 0.04 mol of disulfur dichloride, seal the tube, and stir at room temperature for 3 hours. After the reaction is completed, the reaction mixture is concentrated in vacuo and purified by flash chromatography on silica gel to obtain intermediate 1 with a yield of 91.8%.

[0039] 2) 0.08 mol of 3-allyl-2-hydroxybenzaldehyde and 0.09 mol of triethylamine (TEA) were dissolved in 60 mL of dichloromethane, and 40 mL of dichloromethane solution containing 0.09 mol of intermediate 1 was slowly added at 0°C under nitrogen atmosphere, and the mixture was stirred in an ice bath for 2 h and refluxed in a 40°C water bath for 10 h. After the reaction, the mixture was filtered, and the filtrate was repeatedly washed with saturated brine until neutral, and dichloromethane was removed by rotary evaporation. The intermediate 2 was concentrated and recrystallized to obtain a yield of 82.5%.

[0040] 3) Prepare 100 mL of anhydrous ethanol solution of 0.12 mol succinic acid dihydrazide and 40 mL of anhydrous ethanol solution containing 0.062 mol intermediate 2 respectively and mix them; after adding 0.5 mol acetic acid (AcOH) catalyst, heat the mixed solution under reflux in a 50° C. oil bath for 7.5 h; wait for the solution to gradually cool and crystallize, filter, wash with acetone three times and then vacuum dry; recrystallize again with anhydrous ethanol at 0-5° C., filter and vacuum dry to obtain diacylhydrazone chain extender 1, with a yield of 88.6%, and store at low temperature under sealed inert gas. Diacylhydrazone chain extender 1 has the following structure:

[0041]

[0042] Preparation Example 2

[0043] according to Figure 2 The process shown is to synthesize diacylhydrazone chain extender 2:

[0044] 1) In a 100 mL reaction tube, add 0.02 mol 1,4-dithiane-2,5-di(methyl mercaptan) and 0.02 mol N-bromosuccinimide dissolved in 64 mL 1,4-dioxane, add 0.04 mol disulfur dichloride, seal the tube, and stir at room temperature for 2 h. After the reaction is completed, the reaction mixture is concentrated in vacuo and purified by silica gel chromatography to obtain intermediate 1 with a yield of 92.2%.

[0045] 2) 0.075 mol of 3-(4-hydroxyphenyl)acrolein and 0.08 mol of triethylamine were dissolved in 60 mL of acetone, and 40 mL of acetone ester solution containing 0.09 mol of intermediate 1 was slowly added at 0°C under nitrogen atmosphere, and the mixture was stirred in an ice bath for 2 h and refluxed at 50°C for 10 h. After the reaction, the mixture was filtered, and the filtrate was washed with saturated brine, concentrated and recrystallized to obtain intermediate 2 with a yield of 83.3%;

[0046] 3) 100 mL of a toluene solution of 0.12 mol terephthalic acid dihydrazide and 40 mL of a toluene solution containing 0.062 mol of the intermediate product 2 were prepared and mixed; after adding 0.5 mol of acetic acid catalyst, the mixed solution was heated to reflux in a 55° C. oil bath for 8.5 h; the solution was gradually cooled and crystallized, filtered, washed with acetone three times, and then vacuum dried; recrystallized again with anhydrous ethanol at 0-5° C., filtered, and vacuum dried to obtain a diacylhydrazone chain extender 2 with a yield of 88.4%, and sealed with inert gas and stored at low temperature. The diacylhydrazone chain extender 2 has the following structure:

[0047]

[0048] Preparation Example 3

[0049] according to Figure 3 The process shown is to synthesize the diacylhydrazone chain extender 3:

[0050] 1) Add 0.02 mol of 4'4-dimercaptodiphenyl sulfide and 0.02 mol of N-bromosuccinimide to a 100 mL reaction tube and dissolve in 64 mL of 1,4-dioxane, add 0.04 mol of disulfur dichloride, seal the tube, and stir at room temperature for 2.5 hours. After the reaction is completed, the reaction mixture is concentrated in vacuo and purified by silica gel chromatography to obtain intermediate 1 with a yield of 93.5%.

[0051] 2) 0.06 mol of 2-hydroxycinnamaldehyde and 0.066 mol of triethylamine were dissolved in 60 mL of ethyl acetate, and 40 mL of ethyl acetate solution containing 0.067 mol of intermediate 1 was slowly added at 0°C under nitrogen atmosphere, and the mixture was stirred in an ice bath for 2 h and refluxed at 45°C for 6 h. After the reaction, the mixture was filtered, and the filtrate was washed with saturated brine, concentrated and recrystallized to obtain intermediate 2 with a yield of 84.8%.

[0052] 3) Prepare 100 mL of anhydrous benzene solution containing 0.12 mol of malonic acid dihydrazide and 40 mL of anhydrous benzene solution containing 0.062 mol of intermediate 2 respectively and mix them; add 0.5 mol of acetic acid, and heat the mixed solution under reflux in a 50° C. oil bath for 6 h; wait for the solution to gradually cool and crystallize, filter, wash with acetone three times, and then vacuum dry; recrystallize again with anhydrous ethanol at 0-5° C., filter, and vacuum dry to obtain diacylhydrazone chain extender 3, with a yield of 89.7%, and store at low temperature under sealed inert gas. Diacylhydrazone chain extender 3 has the following structure:

[0053]

[0054] The molecular weights of diacylhydrazone chain extenders 1 to 3 were measured using a Waters 1515 / 2414 gel permeation chromatograph, and the degree of polymerization was calculated. The results are shown in Table 1.

[0055] Table 1

[0056] sample Molecular weight (g / mol) PDI m Preparation Example 1 5188 1.72 7 Preparation Example 2 5052 1.69 7 Preparation Example 3 5054 1.75 7

[0057] From Table 1, the molecular weights of the three diacylhydrazone chain extenders are close, which shows the universality of the preparation of the diacylhydrazone chain extender of the present invention. The significant difference between the three diacylhydrazone chain extenders is whether the carbon-carbon double bond on the polyurethane polymer carbon chain is located in the main chain or the side chain.

[0058] The samples were analyzed and tested using a Bruker spectrometer (Bruker, Coventrv) at 400 MHz. Weigh 50 mg of the sample into a NMR tube, add 0.6 mL of LCDCl3, and scan 16 times. TMS was used for spectral processing. The NMR hydrogen spectrum results of diacylhydrazone chain extenders 1 to 3 are shown in Figures 4 to 6 .

[0059] Diacylhydrazone chain extender 1 1 H NMR: δ10.55 (s, 2H), 8.29 (s, 2H), 8.01 (t, 2H, J = 3.33Hz), 7.57 (d, 2H, J = 5.92Hz), 7.18 (dq, 2H, J = 6. 09,0.86Hz),7.08(t,2H,J=6.0Hz),5.89(ddd,,2H,J=18.98,13.56,10.67,5.39Hz),5.01(dq,4H,J =13.85,4.05Hz),4.44(s,4H),3.81(s,4H),3.65(d,2H,J=3.31Hz),3.37(dq,4H,J=5.26,0.71Hz), 2.37(t,4H,J=6.21Hz), 2.04(t,4H,J=6.61Hz), 1.68(ddd,4H,J=12.28,6.14,0.85Hz), 1.58(m,4H).

[0060] Diacylhydrazone chain extender 2 1 H NMR: δ11.20(s,2H),9.08(t,2H,J=3.31Hz),8.17(dd,2H,J=6.28,1.50Hz),7.96( s,8H),7.47(dq,4H,J=6.30,1.27Hz),7.09(dq,2H,J=12.17,0.67Hz),7.06(dt,4 H,J=6.38,1.34Hz),6.99(q,2H,J=6.40Hz),4.10(d,4H,J=3.42Hz),3.30(m,2H,J =5.03, 2.51Hz), 3.13 (d, 4H, J = 2.34Hz), 2.85 (ddd, 4H, J = 12.61, 10.00, 2.61Hz).

[0061] Diacylhydrazone chain extender 3 1 H NMR: δ10.80 (s, 2H), 8.84 (t, 2H, J = 3.18Hz), 8.11 (dd, 2H, J = 6.22, 0.93Hz), 7. 53(dt,2H,J=6.29,0.57Hz),7.46(s,4H),7.27(td,2H,J=5.20,1.08Hz),7.09 (dt,2H,J=7.56,1.17Hz),7.07(dd,2H,J=7.62,1.17Hz),7.05(td,2H,J=7.58 ,1.17Hz), 6.78(dd,2H,J=8.07,6.48Hz), 3.85(d,4H,J=3.35Hz), 3.16(s,4H).

[0062] Example 1

[0063] A temperature-suppressing anti-cracking concrete waterproofing agent, the preparation steps of which are as follows:

[0064] The raw materials of protocatechuic acid and 1,3-bis(3-hydroxypropyl)-1,1,3,3-tetramethyldisiloxane were pretreated by vacuum dehydration and drying at 120°C;

[0065] Under nitrogen atmosphere, 0.02 mol protocatechuic acid and 0.02 mol 1,3-bis(3-hydroxypropyl)-1,1,3,3-tetramethyldisiloxane were added to a four-necked flask equipped with a mechanical stirring device, a reflux condenser, a thermometer and a constant pressure dropping funnel, and stirred and mixed at room temperature; the temperature was gradually raised to 70°C, and 0.08 mol MDI and 0.23 g DBTDL mixture; continue stirring at 70°C for 1h after the addition is completed; add 15mL of butanone to adjust the viscosity of the system, raise the temperature to 100°C and stir at a constant temperature for 7h; lower the system temperature to 50°C, add 0.045mol of diacylhydrazone chain extender 1, and stir at a constant temperature for 4h; add 0.025mol of triethylamine until the pH of the system is 7.0 and stir for 30min, add 171g of deionized water and stir at 1000rpm for 30min for emulsification and dispersion; remove the residual butanone by rotary evaporation to obtain a polyurethane emulsion waterproofing agent with a solid content of 28%.

[0066] Example 2-3

[0067] A temperature-suppressing anti-cracking concrete waterproofing agent, which is different from Example 1 in that the chain extenders used are diacylhydrazone chain extender 2 and diacylhydrazone chain extender 3, respectively, and to ensure that its solid content is similar to that of Example 1, the mass of deionized water added during emulsification is 176g and 154g respectively, and other raw materials and preparation process are the same as Example 1.

[0068] Example 4

[0069] A temperature-suppressing anti-cracking concrete waterproofing agent, wherein the dihydroxy acid used in the raw materials is caffeic acid, the diisocyanate is 2,6-diisocyanate toluene, and to ensure that the solid content is similar to that in Example 1, the mass of deionized water added during emulsification is 157g, and the remaining raw materials and preparation are the same as in Example 1.

[0070] Example 5

[0071] A temperature-suppressing anti-cracking concrete waterproofing agent, wherein the dihydroxy acid used in the raw materials is glyceric acid, the diisocyanate is cyclohexane-1,4-diisocyanate, and to ensure that the solid content is similar to that in Example 1, the mass of deionized water added during emulsification is 154g, and the remaining raw materials and preparation are the same as in Example 1.

[0072] Example 6

[0073] A temperature-suppressing anti-cracking concrete waterproofing agent, wherein the siloxane diol in the raw materials used is 3-[bis(2-hydroxyethyl)amino]propane-triethoxysilane, and to ensure that its solid content is similar to that in Example 1, the mass of deionized water added during emulsification is 175g, and the remaining raw materials and preparation are the same as in Example 1.

[0074] Example 7

[0075] A temperature-suppressing, crack-resistant concrete waterproofing agent.

[0076] Under nitrogen atmosphere, 0.032 mol protocatechuic acid and 0.008 mol 1,3-bis(3-hydroxypropyl)-1,1,3,3-tetramethyldisiloxane were added to a four-necked flask equipped with a mechanical stirring device, a reflux condenser, a thermometer and a constant pressure dropping funnel, and stirred and mixed at room temperature; the temperature was gradually raised to 70°C, and 0.08 mol MDI and 0.23 g A mixture of N-methylmorpholine; after the addition is completed, stirring is continued at 70°C for 1 hour; 15 mL of butanone is added to adjust the viscosity of the system, the temperature is raised to 100°C and stirred at a constant temperature for 7 hours; the system temperature is lowered to 50°C, 0.045 mol of diacylhydrazone chain extender 1 is added, and the temperature is stirred for 4 hours; 0.032 mol of triethylamine is added until the pH of the system is 7.0 and stirred for 30 minutes, 167 g of deionized water is added and stirred at a high speed of 1000 rpm for 30 minutes for emulsification and dispersion; residual butanone is removed by rotary evaporation to obtain a polyurethane emulsion waterproofing agent with a solid content of 28%.

[0077] Example 8

[0078] A temperature-suppressing, crack-resistant concrete waterproofing agent.

[0079] Under nitrogen atmosphere, 0.008 mol of protocatechuic acid and 0.032 mol of 1,3-bis(3-hydroxypropyl)-1,1,3,3-tetramethyldisiloxane which had been vacuum dried in advance were added to a four-necked flask equipped with a mechanical stirring device, a reflux condenser, a thermometer and a constant pressure dropping funnel, and stirred and mixed at room temperature; the temperature was gradually raised to 70°C, and 0.08 mol of MDI and 0.23 g of 1,3-bis(3-hydroxypropyl)-1,1,3,3-tetramethyldisiloxane were added dropwise at 600 rpm. TEDA mixture; continue stirring at 70°C for 1h after the addition; add 15mL of butanone to adjust the viscosity of the system, heat to 100°C and stir at a constant temperature for 7h; lower the system temperature to 50°C, add 0.045mol of diacylhydrazone chain extender 1, and stir at a constant temperature for 4h; add 0.01mol of triethylamine until the pH of the system is 7.0 and stir for 30min, add 157g of deionized water and stir at 1000rpm for 30min for emulsification and dispersion; remove the residual butanone by rotary evaporation to obtain a polyurethane emulsion waterproofing agent with a solid content of 28%.

[0080] Examples 9-10

[0081] A temperature-suppressing anti-cracking concrete waterproofing agent is different from the embodiment in that the mass of deionized water used is changed to 268g and 123g respectively, and concrete waterproofing agent products with solid contents of 20% and 35% are obtained respectively.

[0082] Comparative Examples 1-3

[0083] A concrete waterproofing agent, the difference is that the chain extenders used are succinic acid dihydrazide, terephthalic acid dihydrazide and malonic acid dihydrazide, respectively. In order to ensure that the solid content is similar to that in Example 1, the masses of deionized water added during emulsification are 86g, 92g and 85g respectively. The amounts of other raw materials and the preparation process are the same as in Example 1.

[0084] Comparative Example 4

[0085] A concrete waterproofing agent, the raw material dosage and preparation process of which are the same as those of Example 1, except that 1,3-bis(3-hydroxypropyl)-1,1,3,3-tetramethyldisiloxane is not added, the dosage of protocatechuic acid is increased to 0.04 mol, and the dosage of triethylamine for neutralization is increased to 0.04 mol; and in order to ensure that its solid content is similar to that of Example 1, the mass of deionized water added during emulsification is 166 g, and other conditions remain unchanged.

[0086] Application example: preparing concrete to which the above-mentioned temperature-suppressing and anti-cracking concrete waterproofing agent is added.

[0087] The temperature-suppressing and crack-resistant concrete waterproofing agents of all the above-mentioned embodiments and comparative examples were diluted with water respectively, added into the concrete mixture at 2% by weight of cement, and mixed evenly to prepare concrete test block samples, and a blank group (reference test block sample) was arranged. In addition, the concrete raw materials also include: 180 parts of cement, 80 parts of mineral powder, 100 parts of fly ash, 800 parts of river sand, 1000 parts of crushed stone, 190 parts of mixing water, and 10 parts of polycarboxylic acid high-efficiency water reducing agent. Among them, the cement is China Resources P·O 42.5 silicate cement; the fine aggregate is a continuously graded medium sand with a fineness modulus of 3.0-2.3 and a mud content of ≤0.5%, Macheng Chuhe Sand and Gravel State-owned Operation Co., Ltd.; the coarse aggregate is a 5-20mm continuously graded construction type I crushed stone with a mud content of ≤0.5%, Xianning Xianning District Xinxin Mining Co., Ltd.; the fly ash is F-class I power plant fly ash with a specific surface area of ​​450m 2 / kg, Wuhan Lianhekang Biotechnology Co., Ltd.; S95 mineral powder, specific surface area 480m 2 / kg, density is 2.68g / cm 3 , Lingshou County Defa Mineral Products Processing Plant; polycarboxylic acid high-efficiency water reducing agent, air content 5%, water bleeding rate 45%, water reduction rate 28%, Hubei Guiyi New Building Materials Co., Ltd.

[0088] Tests were conducted on the concrete samples prepared in each application example:

[0089] Semi-adiabatic temperature rise test: The concrete test block is placed in the temperature measurement test device within 10 minutes of water addition and mixing, and placed in a constant temperature test room at 20±2℃. The temperature change of the concrete test block and the ambient temperature change are recorded by the temperature sensor at a frequency of 1 time / 10min. After the temperature rise peak is measured, the temperature measurement can be stopped after entering the cooling stage for 24 hours. The time and peak temperature of each concrete test block sample and the blank group from the end of water addition and mixing to the hydration exothermic temperature rise of 5℃ are recorded, and the temperature inhibition rate is calculated by the peak temperature ratio of the concrete test block sample of the embodiment and the blank group.

[0090] 48h water absorption ratio and penetration height ratio performance: both are tested in accordance with the standard GB / T 50082-2009 "Standard for test methods of long-term performance and durability of ordinary concrete". Water absorption ratio = 48h water absorption of concrete test block sample / 48h water absorption of blank group. The 48h water absorption of blank group is 1235g / m 2 . Permeability height ratio = permeability height of concrete test block sample / permeability height of blank group; the anti-seepage pressure used is 1.6MPa, constant pressure for 24h; the anti-seepage height of blank group is 80.4mm. The water absorption ratio mainly reflects the water absorption capacity of concrete in a static water environment, while the permeability height ratio reflects the permeability of concrete under pressure water. These two properties comprehensively show the anti-seepage performance of concrete.

[0091] The compressive strength of the concrete test block was tested with reference to the provisions of the national standard GB / T50081-2002 "Standard for Test Methods of Mechanical Properties of Ordinary Concrete", and the ratio of the compressive strength of the concrete test block to the compressive strength of the blank group was the compressive strength ratio. The compressive strength of the blank group was 23.6MPa (7d) and 34.4MPa (28d).

[0092] The above test results are shown in Table 2.

[0093] Table 2

[0094]

[0095] It can be seen from the embodiments that the temperature-suppressing and anti-cracking waterproof agent of the present invention has good waterproof performance, the water absorption ratio of 48d is less than 40%, the penetration height ratio is not more than 30%, which meets the requirements of the first-class products of the national standard JC / T474-2008; the compressive strength ratio meets the requirements of the qualified products of the national standard JC / T474-2008; the temperature inhibition rate is increased to 47% to 57.5%, which meets the performance index requirements of the group standard T / CECS10270-2023.

[0096] Embodiments 1-3 show that the introduction of carbon-carbon double bond groups in waterproofing agents improves the temperature suppression and crack resistance of concrete. Carbon-carbon double bonds have certain reactivity whether they are located in the main chain (embodiments 2-3) or the side chain (embodiment 1) of the polyurethane polymer carbon chain, and form a dense network structure through cross-linking reaction, fill the internal pores of concrete, and effectively prevent the penetration of moisture. It is worth noting that the double bonds of the diacylhydrazone chain extender polymer obtained in Preparation Example 2 and Example 3 are located on the main chain of the polymer, and the π electron cloud of the double bond limits the rotation of the molecular chain segment to a certain extent, thereby increasing the rigidity of the molecular chain, so the compressive strength ratio of the concrete in Example 2 and Example 3 is slightly higher than that in Example 1.

[0097] Compared with Example 1, the polymerization of caffeic acid and isocyanate in Example 4 additionally increases the content of carbon-carbon double bonds, so its temperature suppression and anti-cracking effect is better; the glyceric acid used in Example 5 does not contain a benzene ring and a carbon-carbon double bond, and the corresponding waterproof performance is slightly reduced compared with Example 1. Therefore, the hydroxy dibasic acid can further preferably be a hydroxy dibasic acid containing an unsaturated bond. In Example 6, the siloxane diol molecule additionally contains a tertiary amino group, which can form more hydrogen bonds with concrete raw materials, so its waterproof performance is different; in addition, the tertiary amino group makes the hydrophilicity of the waterproofing agent molecule slightly greater than that of Example 1, so its 48h water absorption ratio is higher.

[0098] The results of Example 1, Examples 7-8, and Comparative Example 4 show the role of siloxane diol in waterproofing agents. The two silyl methyl groups in siloxane diol are easily hydrolyzed into silanol groups in alkaline concrete, and can be combined with silicon dioxide in calcium silicate to form a three-dimensional network structure, thereby improving the overall strength of the product; and the hydrophobic siloxanes are neatly arranged on the pore walls, hindering the penetration of water into the interior, making the concrete more waterproof as a whole. The proportions of siloxane diol in Example 7, Example 1, and Example 8 increase successively, so their waterproof effects also increase accordingly; in Comparative Example 4, siloxane diol is not added, and its waterproof performance for concrete is slightly reduced.

[0099] The test results of Examples 1-3 and Comparative Examples 1-3 prove that the carbon-carbon double bonds, disulfide bonds and acylhydrazone groups rich in the waterproofing agent improved by the present invention work together to inhibit temperature and resist cracking, doubling the temperature inhibition rate and improving the anti-permeability performance by more than 25%; and in combination with Examples 9-10, the proportion of waterproofing agent in concrete should be appropriately adjusted according to actual engineering needs. If it is too little, the anti-cracking and waterproofing performance of the concrete will be insufficient; if it is too much, the flexibility of the concrete will increase and part of the compressive strength will be sacrificed.

[0100] In summary, the temperature-suppressing anti-cracking concrete waterproofing agent provided by the present invention has significantly excellent temperature control, anti-cracking and waterproofing effects. It can be applied to large-scale engineering concrete to meet the construction fields with high waterproofing requirements such as underground engineering and hydraulic structures.

[0101] The embodiments of the present invention have been described above, and the above description is exemplary, not exhaustive, and is not limited to the disclosed embodiments. Many modifications and changes will be apparent to those skilled in the art without departing from the scope and spirit of the described embodiments.

Claims

1. A temperature-suppressing anti-cracking concrete waterproofing agent, characterized in that: Its raw materials include siloxane diol, dihydroxy acid, diisocyanate, catalyst, diacylhydrazone chain extender and water; The molar ratio of the diisocyanate, siloxane diol, dihydroxy acid, and diacylhydrazone chain extender is (1.98-2.05):(0.2-0.8):(0.2-0.8):(1.05-1.2); the solid content of the waterproofing agent is 20%-35%; The diacylhydrazone chain extender is synthesized by the following steps: 1) dithiol hydrocarbon and disulfur dichloride undergo exchange reaction to generate intermediate 1; 2) Intermediate 1 undergoes substitution reaction with hydroxy enal to generate intermediate 2; 3) The intermediate 2 is reacted with alkanedioic acid dihydrazide by Schiff base reaction to obtain a diacylhydrazone chain extender.

2. The concrete waterproofing agent according to claim 1, characterized in that: The conditions of step 1) are as follows: dithiol hydrocarbon and disulfur dichloride are reacted in a sealed state with stirring for 2 to 4 hours in a 1,4-dioxane medium and under the catalyst of N-bromosuccinimide; after the reaction is completed, the reaction mixture is concentrated in vacuo and then purified by silica gel chromatography to obtain intermediate 1; the molar ratio of the dithiol hydrocarbon, disulfur dichloride and N-bromosuccinimide is 1:(3.9 to 4.2):(1.0 to 1.2); the dithiol hydrocarbon includes C1 to C5 aliphatic hydrocarbons containing two terminal thiols, thiane, benzene, biphenyl, naphthalene, diphenyl ether, and diphenyl sulfide.

3. The concrete waterproofing agent according to claim 1, characterized in that: The conditions of step 2) are as follows: in a nitrogen atmosphere, the intermediate 1 and the hydroxy olefin aldehyde are stirred in a dichloromethane, ethyl acetate, anhydrous ethanol or acetone medium with triethylamine as an acid-binding agent in an ice bath at -5 to 5°C for 2 to 3 hours and in a water bath at 40 to 50°C for 6 to 12 hours; after the reaction, the mixture is filtered, washed with saturated brine, acetone is removed by vacuum rotary evaporation, and the intermediate 2 is obtained by concentration and recrystallization; the molar ratio of the hydroxy olefin aldehyde, the intermediate 1 and the triethylamine is 1:(1.1 to 1.5):(0.99 to 1.20); the hydroxy olefin aldehyde is an aldehyde compound containing at least one hydroxyl group and one carbon-carbon double bond.

4. The concrete waterproofing agent according to claim 1, characterized in that: The conditions of step 3) are as follows: in anhydrous benzene, toluene or ethanol, the intermediate 2 and alkanedioic acid dihydrazide are heated to reflux in an oil bath at 50-60° C. for 6-9 hours with acetic acid as a catalyst; after the reaction, the filtrate is filtered through a Buchner funnel, the solvent is removed by rotary evaporation, and the diacylhydrazone chain extender is obtained by concentration, which is sealed and filled with argon and stored at low temperature; the molar ratio of the intermediate 2, alkanedioic acid dihydrazide and acetic acid is 1:(2-2.2):(0.8-1.0); the alkanedioic acid dihydrazide is selected from one or more of C3-C12 aliphatic hydrocarbon dihydrazide, phthalic acid dihydrazide, isophthalic acid dihydrazide and terephthalic acid dihydrazide.

5. The concrete waterproofing agent according to claim 1, characterized in that: The siloxane diol is a siloxane substance containing two hydroxyl groups at the same time; the dihydroxy acid is a monobasic or dibasic carboxylic acid containing two hydroxyl groups.

6. The concrete waterproofing agent according to claim 1, characterized in that: The catalyst is added in an amount of 0.5% to 1.2% of the total mass of the system and is selected from one or more of dibutyltin dilaurate, trihexamethylenediamine, N-alkyldiamine, N-alkylmorpholine, stannous octoate, zinc-bismuth composite catalyst, bismuth isooctanoate, organic zinc, and zinc neodecanoate.

7. The concrete waterproofing agent according to claim 1, characterized in that: The diisocyanate is one or more of 4-toluene diisocyanate, trans-1,4-cyclohexyl diisocyanate, 2,6-toluene diisocyanate, 4,4'-diphenylmethane diisocyanate, dicyclohexylmethane-4,4-diisocyanate, isophorone diisocyanate, 1,6-hexamethylene diisocyanate, and lysine diisocyanate.

8. The method for preparing a temperature-suppressing anti-cracking concrete waterproofing agent according to any one of claims 1 to 7, characterized in that: The following steps are involved: The dihydroxy acid and the siloxane diol were pretreated by vacuum dehydration and drying at 120°C; Subsequently, under a nitrogen atmosphere, the dihydroxy acid and the siloxane diol were added into a four-necked flask equipped with a mechanical stirring device, a reflux condenser, a thermometer and a constant pressure dropping funnel and stirred and mixed at room temperature; Gradually raise the temperature to 60-70°C, and dropwise add the diisocyanate and catalyst mixture under stirring conditions of 500-700rpm; continue stirring at 60-70°C for 1-2h after the addition is completed; add aprotic solvent to adjust the viscosity of the system, raise the temperature to 90-120°C and stir at a constant temperature for 5-9h; reduce the system temperature to 40-60°C, add a diacylhydrazone chain extender, and stir at a constant temperature for 3-4h; add a neutralizer until the pH of the system is 7.0-7.5 and stir for 30min, add deionized water and stir at a high speed of 1000-1500rpm for 30min for emulsification and dispersion; remove the residual aprotic solvent by rotary evaporation to obtain a polyurethane emulsion waterproofing agent.

9. The preparation method according to claim 8, characterized in that: The aprotic solvent is one or more of butanone, dioxane, dimethylformamide, benzene, and toluene; and the neutralizer is one of NH4OH, NaOH, monoethylamine, diethylamine, triethylamine, and triethanolamine.

10. Use of the temperature-suppressing anti-cracking concrete waterproofing agent according to any one of claims 1 to 7 in the preparation of concrete.

Images