An organosilicon polycondensate type high-performance water reducer and its preparation method

Abstract

The present invention discloses a high-performance water reducer of organosilicon condensate type and a preparation method thereof. Liquid ammonia and ethylene oxide undergo a ring-opening reaction to obtain an N-hydroxyethylamine compound. The N-hydroxyethylamine compound is condensed with formaldehyde to obtain an N-hydroxyethyl-N-hydroxymethylamine intermediate. The N-hydroxyethyl-N-hydroxymethylamine intermediate undergoes an esterification reaction with phosphorus trichloride to obtain an amino alcohol intermediate containing a phosphate ester group. The amino alcohol intermediate containing a phosphate ester group is polymerized with a dihydrogen-terminated polydimethylsiloxane oligomer to obtain an organosilane-modified oligomer containing amino and phosphate ester groups, and then a high-performance water reducer is obtained through high-temperature dehydration. The phosphate ester group, siloxane group, and amino group connected to the high-performance water reducer of the present invention reduce the liquid-solid interfacial energy and improve the dispersing ability, dispersion stability, and anti-sludge ability of the high-performance water reducer to cement particles. The water reducer of the present invention has a protective effect on the steel bars in reinforced concrete, the preparation process is simple, the product has good uniformity, realizes low cost, green environmental protection, and multifunctionalization, and has good application prospects.

Description

Technical Field

[0001] The present invention belongs to concrete admixtures, and particularly relates to a high-performance water reducer of an organosilicon condensate type containing phosphoric acid ester groups and amino groups and a preparation method thereof. Background Art

[0002] In recent years, according to the characteristics of the molecular structure of polycarboxylate water reducers that can be designed, by changing functional monomers, side chain lengths, grafting densities, etc., the adsorption of polycarboxylate high-performance water reducers on the soil surface is reduced, and the number of polycarboxylate high-performance water reducer molecules inserted into the interlayer of soil minerals is inhibited to improve the anti-mud ability of polycarboxylate high-performance water reducers. However, this method of modifying polycarboxylate high-performance water reducers will reduce the dispersion effect of polycarboxylate high-performance water reducers, and the raw material cost is high and the synthesis process is complex. In addition, a free radical copolymerization reaction can be carried out using a silane monomer containing a carbon-carbon double bond and sodium methallylsulfonate, methoxypolyethylene glycol acrylate or allyl polyethylene glycol monomer to introduce a siloxane group into the hydrophobic chain segment of the polycarboxylate high-performance water reducer, and a silane-modified polycarboxylate high-performance water reducer is prepared. The silane-modified polycarboxylate high-performance water reducer undergoes silanol chemical bonding on the surface of cement particles, increasing the adsorption and adsorption driving force of the water reducer molecules on the surface of cement particles, and improving the dispersion ability of the polycarboxylate high-performance water reducer for cement. However, the monomers of the organosilicon-modified polycarboxylate high-performance water reducer are mainly silane coupling agents containing carbon-carbon double bonds and silane synthetic compounds containing double bonds. The sources of silane monomers are limited and the prices are expensive. At the same time, the proportion of organosilicon groups in the molecules of the silane-modified polycarboxylate high-performance water reducer is small, and the molecular weight of the silane-modified polycarboxylate high-performance water reducer is small. And existing organosilicon compounds are not easily reacted with active linear polymers, and the prepared organosilicon-modified polycarboxylate high-performance water reducers have poor uniformity and unsatisfactory setting retardation effects. These problems have hindered the application of silicon-based modified polycarboxylate high-performance water reducers in high-performance concrete. Therefore, developing a multifunctional high-performance water reducer with a simple production process, low cost, good dispersion ability and excellent anti-mud effect is of great significance for promoting the development of high-performance concrete technology. Summary of the Invention

[0003] Object of the Invention: The object of the present invention is to provide a high-performance water reducer of a linear organosilicon condensate type containing phosphoric acid ester groups and amino groups; the second object of the present invention is to provide a preparation method of the above organosilicon condensate type high-performance water reducer.

[0004] Technical Solution: A high-performance water reducer of an organosilicon condensate type of the present invention, and the molecular structural formula of the water reducer is:

[0005]

[0006] Wherein, m is an integer of 30 to 40, and n is an integer of 4 to 6; the weight average molecular weight of the water reducer is 12,000 to 16,000.

[0007] Based on the dispersion mechanism of anionic groups on cement particles and the reaction characteristics of silane compounds, this invention abandons the existing technical approach for preparing modified polycarboxylate anti-sludge superplasticizers using organosilane compounds. Based on the principle that phosphate groups have a strong adsorption effect on cement particles, generating electrostatic repulsion on the surface of cement particles to effectively disperse the cement particles, a non-sulfonic acid-based and non-carboxylic acid-type high-performance superplasticizer containing phosphate groups and amino groups, namely an organosilicon condensate, is prepared.

[0008] This invention also protects a preparation method of an organosilicon condensate-type high-performance superplasticizer, which includes the following steps:

[0009] Step 1: Mix liquid ammonia, ethylene oxide, and absolute ethanol, adjust the pH value of the solution to 7 - 8, raise the temperature for reaction to obtain a liquid of N-hydroxyethylamine compound; continue to adjust the pH value of the system to 9 - 10, dropwise add a quantitative formaldehyde solution, and adjust the temperature for reaction to obtain an N-hydroxyethyl-N-hydroxymethylamine intermediate.

[0010] Step 2: Prepare a chloroform solution containing phosphorus trichloride, mix it with the N-hydroxyethyl-N-hydroxymethylamine intermediate, dropwise add a triethylamine solution during the mixing process, and raise the temperature for reaction; after the reaction, add a saturated sodium bicarbonate aqueous solution and continue the reaction until no bubbles are released from the product to obtain an amine alcohol intermediate containing phosphate groups.

[0011] Step 3: Mix a dihydroxy-terminated polydimethylsiloxane oligomer and the amine alcohol intermediate containing phosphate groups, adjust the pH value of the system to 11 - 12, raise the temperature for polymerization reaction to obtain a liquid of an organosilane-modified oligomer containing amino and phosphate groups.

[0012] Step 4: Adjust the pH of the solution of the linear organosilane-modified oligomer containing amino and phosphate groups to 10 - 11 with sodium hydroxide, raise the temperature for dehydration condensation reaction to prepare an organosilicon condensate containing phosphate groups, amino groups, and a linear structure.

[0013] Step 5: Add a sodium hydroxide solution to the organosilicon condensate containing phosphate groups, amino groups, and a linear structure, adjust the pH value of the system to 11 - 12, naturally cool to the ambient temperature, and cure in the reaction vessel to prepare the organosilicon condensate-type high-performance superplasticizer.

[0014] Furthermore, in the above Step 1, the mass ratio of liquid ammonia, ethylene oxide, absolute ethanol, and methanol solution is 6.4 - 6.5: 2.4 - 2.5: 4.8 - 5.0: 11.5 - 12.0.

[0015] Furthermore, in the above Step 1, the reaction temperature for the temperature-raising reaction is 60 - 70 °C, and the reaction time is 4 - 5 hours; the reaction temperature for the temperature-adjusting reaction is 40 - 45 °C, and the reaction time is 2 - 3 hours.

[0016] Further, in the second step, the mass ratio of the chloroform solution of phosphorus trichloride, the N-hydroxyethyl-N-hydroxymethylamine intermediate, and the saturated sodium bicarbonate aqueous solution is 32 - 33: 20.5 - 21: 5.25 - 5.30; wherein, the specific preparation of the chloroform solution of phosphorus trichloride is: 16 - 16.5 kg of phosphorus trichloride is added to every 32.0 - 33.0 kg of the chloroform solution.

[0017] Further, in the second step, the reaction temperature for the temperature-raising reaction is 55 - 60 °C, and the reaction time is 5 - 6 hours; the reaction temperature for the continuous reaction is 30 - 35 °C, and the reaction time is 2 - 3 hours.

[0018] Further, in the third step, the mass ratio of the dihydroxy-terminated polydimethylsiloxane oligomer and the alcoholamine intermediate containing a phosphoric acid ester group is 270 - 275: 25 - 26.

[0019] Further, in the third step, the reaction temperature for the polymerization reaction is 80 - 85 °C, and the reaction time is 6 - 7 hours.

[0020] Further, in the fourth step, the reaction temperature for the dehydration condensation reaction is 90 - 95 °C, and the reaction time is 5 - 6 hours.

[0021] Further, in the fifth step, the weight-average molecular weight of the organosilicon condensate type high-range water reducer is 12456 - 15471, the degree of molecular polymerization is 4 - 6, the solid content is 23 - 30%, and the pH is 10 - 11.

[0022] The preparation process of the present invention is as follows: The present invention uses liquid ammonia, ethylene oxide, formaldehyde, phosphorus trichloride, and a water-soluble dihydroxy-terminated polydimethylsiloxane oligomer as reaction monomers. First, under the action of anhydrous sodium carbonate, the active hydrogen in liquid ammonia undergoes a ring-opening reaction with ethylene oxide to obtain an N-hydroxyethylamine compound. Under strong alkaline conditions, the hydrogen on the N-hydroxyethylamine compound undergoes a condensation reaction with formaldehyde to obtain an N-hydroxyethyl-N-hydroxymethylamine intermediate. Then, in the presence of triethylamine, the terminal hydrogen on two N-hydroxyethyl-N-hydroxymethylamine intermediates undergoes an esterification reaction with phosphorus trichloride to obtain an amine alcohol intermediate containing a phosphoric acid ester group. The terminal hydroxyl group in the molecule of the amine alcohol intermediate containing a phosphoric acid ester group undergoes a polymerization reaction with the active hydrogen of the dihydroxy-terminated polydimethylsiloxane oligomer to form an organosilane-modified oligomer containing a phosphoric acid ester group and an amino group. Finally, the organosilane-modified oligomer containing a phosphoric acid ester group and an amino group undergoes a high-temperature dehydration polycondensation reaction to prepare an organosilicon condensate type high-range water reducer containing a phosphoric acid ester group, an amino group, and a straight-chain structure.

[0023] The principle of the present invention is as follows: Adding an efficient water-reducing agent of an organosilicon condensate type containing phosphate groups, amino groups, and linear chains can effectively reduce the interfacial energy at the liquid-solid interface in the cement system. The adsorption and chemical bonding of the phosphate groups on the molecular chain of the efficient water-reducing agent to the cement particles improve the dispersing ability of the efficient water-reducing agent for the cement particles. The phosphate groups also have a certain protective effect on the steel bars in reinforced concrete, reducing the usage amount of rust inhibitors in reinforced concrete. The amino groups improve the dispersion stability of the efficient water-reducing agent for the cement particles. The siloxane groups on the main chain of the efficient water-reducing agent molecule form covalent bonds on the surface of the cement particles, further enhancing the adsorption of the organosilicon condensate on the cement surface, the dispersing ability of the cement particles, the anti-sludge effect, and the setting time of the fresh concrete. Using a polydimethylsiloxane oligomer capped with dihydroxy groups to replace carbon-carbon double bond-containing silane coupling agents and silane compounds as reaction monomers broadens the raw material sources for preparing efficient water-reducing agents with anti-sludge effects. The water-soluble polydimethylsiloxane oligomer capped with dihydroxy groups as a reaction monomer increases the number of organosilicon alkyl groups on the efficient water-reducing agent molecule and the molecular weight of the organosilicon condensate type efficient water-reducing agent.

[0024] Beneficial effects: Compared with the prior art, the present invention has the following remarkable advantages:

[0025] (1) In the molecular chain of the linear organosilicon condensate efficient water-reducing agent of the present invention, the silicon groups and phosphate groups can effectively reduce the interfacial energy at the liquid-solid interface in the cement system, increase the adsorption of the organosilicon condensate efficient water-reducing agent on the surface of the cement particles, the adsorption driving force, and the electrostatic repulsion force, and improve the dispersing ability and anti-sludge ability of the efficient water-reducing agent for the cement particles. Without changing the initial fluidity of the concrete, the anti-sludge effect, and the rust inhibition effect on the steel bars in the concrete, the usage cost of the efficient water-reducing agent and the rust inhibitor per cubic meter of concrete can be reduced by 6.32 yuan, and the compounding cost of the anti-sludge sacrificial agent can be saved by 0.56 yuan.

[0026] (2) The efficient water-reducing agent of the organosilicon condensate type containing phosphate groups, amino groups, and linear chains prepared by the present invention also avoids using toxic substances such as concentrated sulfuric acid and formaldehyde as raw materials in the production of traditional sulfonic acid-based efficient water-reducing agents. It reduces the emission of highly toxic waste gases during the production process and the negative impacts on the environment and public health, realizing the green production of efficient water-reducing agents. It improves the problems such as poor water solubility of unsaturated double bond silanes, low molecular weight of silane-modified polycarboxylate efficient water-reducing agents, and poor dispersing effect on cement particles during the preparation process of existing silicon-based modified polycarboxylate efficient water-reducing agents.

[0027] (3) The preparation of the high-performance water reducer of organosilicon condensate type containing phosphate groups, amino groups, and linear chains in the present invention can effectively increase the number of organosilane groups and the molecular weight in the high-performance water reducer of organosilicon condensate. The raw materials are extensive and inexpensive. For every ton of the high-performance water reducer of organosilicon condensate type containing phosphate groups and amino groups produced, the raw material cost can be saved by 178 yuan. This method for preparing the high-performance water reducer also expands the source of raw materials for preparing the high-performance water reducer with anti-sludge effect; the high-performance water reducer of organosilicon condensate type containing phosphate groups and amino groups is prepared by addition, condensation, polymerization, and high-temperature dehydration, avoiding the free radical polymerization step in the preparation of organosilicon-modified polycarboxylate high-performance water reducer, shortening the production time, and improving the production efficiency. For every ton of the high-performance water reducer of organosilicon condensate type containing phosphate groups and amino groups produced, the production cost can be reduced by 26.9 yuan.

[0028] (4) The present invention uses a water-soluble dihydroxy-terminated polydimethylsiloxane oligomer as the raw material for the high-performance water reducer, and the prepared high-performance water reducer product of organosilicon condensate type containing phosphate groups and amino groups has good uniformity and good retarding performance.

[0029] (5) Calculated based on the annual production of 4000 tons of the high-performance water reducer of linear organosilicon condensate type, excluding the environmental benefits generated by reducing waste gas emissions, only the raw material and production costs can save 712,000 yuan. The economic benefits of 107,600 yuan can be generated by saving production equipment, investment costs, simplifying the process, and reducing production time. Based on the fact that 4000 tons of this high-performance water reducer of organosilicon condensate type containing phosphate groups and amino groups can be used to prepare 8.89×10 5 cubic meters of concrete, the cost of the admixture materials in the high-performance water reducer can be saved by 6,116,300 yuan. The total economic benefits generated by the annual production of 4000 tons of this linear organosilicon condensate type high-performance water reducer amount to 6,935,900 yuan. Description of the Drawings

[0030] Figure 1 shows the surface tension of the high-performance water reducer solution of organosilicon condensate type containing phosphate groups, amino groups, and linear chains at different concentrations;

[0031] Figure 2 shows the water reduction rate of the high-performance water reducer of organosilicon condensate type containing phosphate groups, amino groups, and linear chains at different dosages;

[0032] Figure 3 shows the change of the slump of the concrete mixed with the high-performance water reducer of organosilicon condensate type containing phosphate groups, amino groups, and linear chains over time;

[0033] Figure 4 shows the initial setting time of the concrete mixed with the high-performance water reducer of organosilicon condensate type containing phosphate groups, amino groups, and linear chains at different dosages;

[0034] Figure 5 The final setting time of concrete with different dosages of a highly efficient water reducer of organosilicon condensate type containing phosphate groups, amino groups and linear chains.

[0035] Figure 6 The change of slump of concrete with different mud contents and doped with a highly efficient water reducer of organosilicon condensate type containing phosphate groups, amino groups and linear chains over time.

[0036] Figure 7 The change of compressive strength of concrete with different mud contents and doped with a highly efficient water reducer of organosilicon condensate type containing phosphate groups, amino groups and linear chains with the curing age.

[0037] Figure 8 The change of flexural strength of concrete with different mud contents and doped with a highly efficient water reducer of organosilicon condensate type containing phosphate groups, amino groups and linear chains with the curing age.

[0038] Figure 9 The change of the corrosion potential of steel bars in hardened concrete with different dosages of a highly efficient water reducer of organosilicon condensate type containing phosphate groups, amino groups and linear chains over time.

[0039] Figure 10 The preparation process of a highly efficient water reducer of organosilicon condensate type containing phosphate groups and amino groups. Detailed implementation manners

[0040] The technical solutions of the present invention will be further described in detail below with reference to the accompanying drawings and embodiments.

[0041] In this embodiment, the experimental methods are all conventional methods unless otherwise specified; the reagents and materials can be obtained from commercial channels unless otherwise specified. For the specific preparation process, see Figure 10 .

[0042] Among them, high-purity liquid ammonia (industrial grade) is supplied by Changzhou Yuebang Chemical Co., Ltd.; ethylene oxide is produced by Yangzi Petrochemical-BASF Co., Ltd.; anhydrous ethanol (analytical pure, purity 97%) is produced by Wuxi Youwei Chemical Co., Ltd.; 37% formaldehyde is produced by Shandong Guozheng Chemical Co., Ltd.; phosphorus trichloride (PCl3) is produced by Shandong Weijin Chemical Technology Co., Ltd.; chloroform is produced by Yangzhou Xinyie Chemical Factory; triethylamine is produced by Shijiazhuang Century Longxin Trading Co., Ltd.; sodium bicarbonate (NaHCO3) is purchased from Suzhou Shenglongteng Chemical Technology Co., Ltd.; water-soluble dihydroxy-terminated polydimethylsiloxane oligomer (industrial grade, viscosity 450-1090 mPa·s, weight-average molecular weight 2800-3000, degree of polymerization m = 35) is produced by Qingdao Deming Chemical Co., Ltd.

[0043] Example 1

[0044] Step 1: Weigh 6.4 kg of liquid ammonia, 2.4 kg of ethylene oxide, and 4.8 kg of absolute ethanol and put them into a reaction vessel equipped with a stirrer, a thermometer, a dropping funnel, and a reflux condenser. Start the stirrer and stir for 35 minutes to completely dissolve the liquid ammonia and ethylene oxide in the absolute ethanol to form a homogeneous solution. Add 1.25 kg of anhydrous sodium carbonate solution, adjust the pH value of the solution to 7.76, keep the system temperature at 70 °C, and stir the mixture to react at this temperature for 4.5 hours. Then, remove the absolute ethanol solvent by vacuum distillation. Add 1.15 kg of 40% (weight percentage) sodium hydroxide solution to the reaction solution and adjust the pH value of the system to 9.87. Stir the mixture solution and slowly add 11.5 kg of 37% formaldehyde solution dropwise within 40 minutes. React at 45 °C for 2.5 hours to obtain a light yellow N-hydroxyethyl-N-hydroxymethylamine intermediate solution.

[0045] Step 2: Put 16 kg of phosphorus trichloride and 32.0 kg of chloroform solution into an ice-water bath and continuously stir to completely dissolve the phosphorus trichloride in the chloroform solution. Add 20.5 kg of N-hydroxyethyl-N-hydroxymethylamine intermediate to the reaction vessel, keep the system temperature at 35 °C, slowly add 8.5 kg of triethylamine solution dropwise within 35 minutes, raise the reaction temperature to 60 °C and react for 5.5 hours. Finally, add 5.25 kg of saturated sodium bicarbonate aqueous solution to the above solution and react at 35 °C for 2.5 hours until no bubbles are released from the product. Then, remove the chloroform by vacuum distillation to obtain an amine alcohol intermediate containing sodium phosphate ester.

[0046] Step 3: Add 270 kg of dihydroxy-terminated polydimethylsiloxane oligomer and 25 kg of amine alcohol intermediate containing phosphate ester group into a reaction vessel equipped with a stirrer, a thermometer, and a reflux condenser. Add 695 kg of mixed water, start the stirrer and stir to completely dissolve the dihydroxy-terminated polydimethylsiloxane oligomer and the amine alcohol intermediate containing phosphate ester group in water to form a homogeneous and clear solution. Adjust the pH value of the system to 11.53 with 40% sodium hydroxide and continuously stir the mixture solution. Keep the temperature at 85 °C and react for 6.5 hours. The product changes from light yellow to dark yellow to obtain an organosilane-modified oligomer liquid containing amino and phosphate ester groups.

[0047] Step 4: Rapidly stir the above 995 kg of linear organosilane-modified oligomer containing amino and phosphate groups, adjust the pH of the solution to 10.51 with 40% sodium hydroxide, and react at 95 °C for 6 hours. The linear organosilane-modified oligomer containing amino and phosphate groups undergoes intermolecular high-temperature dehydration to prepare an organosilicon condensate containing phosphate groups, amino groups, and linear chains; in the later stage of the reaction, add a 40% sodium hydroxide solution to adjust the pH value of the system to 11.54, and naturally cool to ambient temperature, and cure in the reaction vessel for 3 hours; obtain a dark yellow organosilicon condensate type (DEEPA-Si-SP) superplasticizer with a pH value of 10.98, a solid content of 27.19%, a molecular polymerization degree of 4, and a weight-average molecular weight of 13534.

[0048] See Table 1 for the physicochemical properties of DEEPA-Si-SP

[0049] Table 1

[0050]

[0051]

[0052] Surface tension is an important aspect to characterize the physicochemical properties of superplasticizer solutions. There is a certain relationship between the surface tension of superplasticizer solutions and the dispersion of cement particles. When adding a superplasticizer to disperse cement particles, the specific surface area increases and the free energy of the system decreases. In the experiment, first, prepare superplasticizer solutions with different concentrations of 0.6 - 15 g / L, then put the superplasticizer solutions into the test container, place the platinum-iridium metal ring into the superplasticizer solution, and slowly lift the platinum-iridium ring from the superplasticizer solution until it separates from the superplasticizer solution. The maximum force value when the platinum-iridium ring breaks is the surface tension of the superplasticizer solution. The surface tensions of superplasticizer solutions containing phosphate groups, amino groups, and linear organosilicon condensates at different concentrations are as Figure 2 shown. It can be seen from the figure that as the concentration of the superplasticizer increases, the surface tension decreases. At higher concentrations, the solution of the organosilicon condensate superplasticizer containing phosphate groups, amino groups, and linear chains has a lower surface tension, indicating that the organosilicon condensate superplasticizer containing phosphate groups, amino groups, and linear chains has good surface activity.

[0053] Example 2

[0054] Step 1: Weigh 6.5 kg of liquid ammonia, 2.5 kg of ethylene oxide, and 5.0 kg of absolute ethanol and put them into a reaction vessel equipped with a stirrer, a thermometer, a dropping funnel, and a reflux condenser. Start the stirrer and stir for 30 minutes to completely dissolve the liquid ammonia and ethylene oxide in the absolute ethanol to form a homogeneous solution. Add 1.30 kg of anhydrous sodium carbonate solution, adjust the pH value of the solution to 7.45, keep the system temperature at 60 °C, and stir the mixture to react at this temperature for 4 hours. Then, distill off the absolute ethanol solvent under reduced pressure. Add 1.20 kg of 40% (by weight) sodium hydroxide solution to the reaction solution, and adjust the pH value of the system to 9.38. Stir the mixture solution, and slowly add 12.0 kg of 37% formaldehyde solution dropwise within 50 minutes, and react at 40 °C for 2 hours to obtain a pale yellow N-hydroxyethyl-N-hydroxymethylamine intermediate solution.

[0055] Step 2: Put 16.5 kg of phosphorus trichloride and 33.0 kg of chloroform solution into an ice-water bath, and continuously stir to completely dissolve the phosphorus trichloride in the chloroform solution. Add 21 kg of N-hydroxyethyl-N-hydroxymethylamine intermediate to the reaction vessel, keep the system temperature at 30 °C, slowly add 8.6 kg of triethylamine solution dropwise within 25 minutes, raise the reaction temperature to 50 °C and react for 5 hours. Finally, add 5.30 kg of saturated sodium bicarbonate aqueous solution to the above solution, and react at 30 °C for 2 hours until no bubbles are released from the product. Then, distill off the chloroform under reduced pressure to obtain an amino alcohol intermediate containing sodium phosphate ester.

[0056] Step 3: Add 275 kg of dihydrogen-terminated polydimethylsiloxane oligomer and 26 kg of amino alcohol intermediate containing phosphate ester group into a reaction vessel equipped with a stirrer, a thermometer, and a reflux condenser. Add 700 kg of mixed water, start the stirrer to stir, and completely dissolve the dihydrogen-terminated polydimethylsiloxane oligomer and the amino alcohol intermediate containing phosphate ester group in water to form a homogeneous and clear solution. Adjust the pH value of the system to 11.41 with 40% sodium hydroxide, and continuously stir the mixture solution. Keep the temperature at 80 °C and react for 6 hours. The product changes from pale yellow to dark yellow to obtain an organosilane-modified oligomer liquid containing amino and phosphate ester groups.

[0057] Step 4: Rapidly stir the above 1000 kg of linear organosilane-modified oligomers containing amino and phosphate groups, adjust the pH of the solution to 10.86 with 40% sodium hydroxide, and react at 90 °C for 6 hours. The linear organosilane-modified oligomers containing amino and phosphate groups undergo intermolecular high-temperature dehydration to prepare organosilicon condensates containing phosphate groups, amino groups, and linear chains. In the later stage of the reaction, add a 40% sodium hydroxide solution to adjust the pH value of the system to 11.25, naturally cool to the ambient temperature, and age in the reaction vessel for 2 hours. Obtain a highly effective water-reducing agent of dark yellow organosilicon condensate type containing phosphate groups, amino groups, and linear chains with a pH value of 10.28, a solid content of 28.74%, a molecular polymerization degree of 6, and a weight-average molecular weight of 14578.

[0058] Example 3

[0059] Step 1: Weigh 6.4 kg of liquid ammonia, 2.5 kg of ethylene oxide, and 4.9 kg of absolute ethanol and put them into a reaction vessel equipped with a stirrer, thermometer, dropping funnel, and reflux condenser. Start the stirrer and stir for 30 minutes to completely dissolve the liquid ammonia and ethylene oxide in the absolute ethanol to form a homogeneous solution. Add 1.30 kg of anhydrous sodium carbonate solution to adjust the pH value of the solution to 7.50, keep the system temperature at 65 °C, and stir the mixture and react at this temperature for 5 hours. Then, remove the absolute ethanol solvent by vacuum distillation. Add 1.20 kg of 40% (weight percentage) sodium hydroxide solution to the reaction solution to adjust the pH value of the system to 10. Stir the mixture solution and slowly add 12.0 kg of 37% formaldehyde solution dropwise within 40 minutes, and react at 45 °C for 3 hours to obtain a light yellow N-hydroxyethyl-N-hydroxymethylamine intermediate solution.

[0060] Step 2: Put 16 kg of phosphorus trichloride and 33.0 kg of chloroform solution into an ice-water bath, and continuously stir to completely dissolve the phosphorus trichloride in the chloroform solution. Add 21 kg of the N-hydroxyethyl-N-hydroxymethylamine intermediate to the reaction vessel, keep the system temperature at 40 °C, slowly add 8.6 kg of triethylamine solution dropwise within 40 minutes, raise the reaction temperature to 60 °C and react for 6 hours. Finally, add 5.25 kg of saturated sodium bicarbonate aqueous solution to the above solution and react at 35 °C for 3 hours until no bubbles are released from the product, and remove the chloroform by vacuum distillation to obtain an amine alcohol intermediate containing sodium phosphate.

[0061] Step 3: Add 275 kg of dihydroxy-terminated polydimethylsiloxane oligomer and 25 kg of alcohol amine intermediate containing phosphate ester group into a reaction vessel equipped with a stirrer, a thermometer and a reflux condenser. Then add 698 kg of mixed water, start the stirrer to stir, and completely dissolve the dihydroxy-terminated polydimethylsiloxane oligomer and the alcohol amine intermediate containing phosphate ester group in water to form a homogeneous and clear solution. Adjust the pH value of the system to 12 with 40% sodium hydroxide, and continuously stir the mixture solution. Keep the temperature at 85 °C and react for 7 hours. The product changes from light yellow to dark yellow, and a liquid of organosilane-modified oligomer containing amino group and phosphate ester group is obtained.

[0062] Step 4: Rapidly stir the above 998 kg of linear organosilane-modified oligomer containing amino group and phosphate ester group, adjust the pH of the solution to 10 with 40% sodium hydroxide, and react at 95 °C for 5 hours. The linear organosilane-modified oligomer containing amino group and phosphate ester group undergoes intermolecular high-temperature dehydration to prepare an organosilicon condensate containing phosphate ester group, amino group and linear structure. In the later stage of the reaction, add 40% sodium hydroxide solution to adjust the pH value of the system to 11, and naturally cool to the ambient temperature, and age in the reaction vessel for 2 hours. A dark yellow superplasticizer of organosilicon condensate type containing phosphate ester group, amino group and linear structure with a pH value of 10.59, a solid content of 27.15%, a molecular polymerization degree of 5 and a weight average molecular weight of 16678 is obtained.

[0063] Specific application

[0064] Example 4

[0065] Study the water reduction rate and concrete performance of the superplasticizer of organosilicon condensate type containing phosphate ester group, amino group and linear structure at different dosages

[0066] Raw materials are as follows: The cement is Jiangnan-Xiaonoda PⅡ 52.5 portland cement, the fine aggregate is river sand with a particle size less than 5 mm and a fineness modulus of 2.46. The coarse aggregate is continuously graded gravel, and the gravel is in two grades, with 5-20 mm gravel accounting for 40% and 20-40 mm gravel accounting for 60%.

[0067] Concrete mix proportion with the superplasticizer of organosilicon condensate type containing phosphate ester group, amino group and linear structure: Add 0-0.6 wt% of the superplasticizer of organosilicon condensate type containing phosphate ester group, amino group and linear structure into the concrete, and study the water reduction rate of this superplasticizer at different dosages. In the single concrete mixture, the cement dosage is 330 kg / m 3 , the coarse aggregate is 1158 kg / m 3 , and the sand ratio is 39%. Adjust the amount of mixing water to control the slump of the concrete at 70-90 mm. The concrete mix proportion with the superplasticizer is shown in Table 2.

[0068] Table 2

[0069]

[0070] Fresh property detection of concrete incorporated with high-range water reducer of organosilicon condensate type containing phosphate group, amino group and linear chain: Put 330 kg of cement, 710 kg of fine aggregate and 1158 kg of coarse aggregate into a mixer and mix for 2 minutes at a stirring speed of 30 revolutions per minute. Then, add 135 - 200 kg of mixing water of high-range water reducer of organosilicon condensate type containing phosphate group, amino group and linear chain with different dosages into the mixer and stir for 2 minutes at a stirring speed of 30 revolutions per minute. To avoid the accumulation of the mixture at the bottom of the container, manually stir the slurry with a trowel twice. Finally, mix for 2 minutes at a stirring speed of 60 revolutions per minute to remove the air bubbles in the fresh concrete slurry. After measuring the initial slump flow of the fresh concrete, put the fresh concrete into a metal container, and cover the metal container with a wet cloth. Re-measure the slump flow of the concrete after 30, 60, 90 and 120 minutes, and evaluate the retention of the slump flow of the concrete incorporated with high-range water reducer of organosilicon condensate type containing phosphate group, amino group and linear chain (DEEPA-Si-SP). Measure the setting time of the concrete incorporated with high-range water reducer of organosilicon condensate type containing phosphate group, amino group and linear chain by using a penetration resistance instrument according to the method of GB 8076 - 1997.

[0071] Figure 2 The water reduction rates of the high-range water reducer of organosilicon condensate type containing phosphate group, amino group and linear chain at different dosages are shown as follows. It can be seen from the figure that with the increase of the dosage of the high-range water reducer of organosilicon condensate type containing phosphate group, amino group and linear chain, the water reduction rate increases continuously. At the dosage of 0.6%, the water reduction rate of the high-range water reducer of organosilicon condensate type containing phosphate group and amino group and linear chain has reached more than 20%.

[0072] Figure 3 The variation of the slump of the concrete incorporated with high-range water reducer of organosilicon condensate type containing phosphate group, amino group and linear chain with time at different dosages is shown as follows. It can be seen from the figure that with the increase of the standing time, the slumps of all the concretes incorporated with high-range water reducer of organosilicon condensate type containing phosphate group, amino group and linear chain decrease. With the increase of the dosage of the high-range water reducer of organosilicon condensate type containing phosphate group, amino group and linear chain, the slump loss rate of the concrete slightly increases during the same standing time. The concrete incorporated with high-range water reducer of organosilicon condensate type containing phosphate group, amino group and linear chain can maintain good fluidity for a long time.

[0073] Figure 4 and Figure 5The setting times of concrete with different dosages of a high-range water reducer based on organosilicon polycondensate containing phosphate groups, amino groups, and linear chains are shown. It can be seen from the figure that the concrete with the high-range water reducer based on organosilicon polycondensate containing phosphate groups, amino groups, and linear chains has a longer setting time than the blank concrete. As the dosage of the high-range water reducer increases, both the initial setting time and the final setting time of the concrete increase. When a relatively large amount of the high-range water reducer based on organosilicon polycondensate containing phosphate groups, amino groups, and linear chains is added to the concrete, the increasing rate of the initial setting time and the final setting time of the concrete slows down.

[0074] Example 5

[0075] Study the anti-sludge performance of the high-range water reducer based on organosilicon polycondensate containing phosphate groups, amino groups, and linear chains.

[0076] Mix proportion of concrete with the high-range water reducer based on organosilicon polycondensate containing phosphate groups, amino groups, and linear chains: To investigate the anti-sludge effect of the high-range water reducer based on organosilicon polycondensate containing phosphate groups, amino groups, and linear chains (DEEPA-Si-SP), the dosage of the high-range water reducer was fixed at 0.5%. P.Ⅰ 42.5 ordinary Portland cement, fly ash, coarse aggregate was 5-25 mm continuously graded gravel, and fine aggregate was river sand with a fineness modulus of 2.21. The mud content of the river sand fine aggregate was 6.02%. The muddy river sand was partially washed and completely washed to obtain fine aggregates with mud contents of 0%, 2.54%, 3.79%, and 6.02%. The fine aggregates of river sand with mud contents of 0%, 2.54%, 3.79%, and 6.02% were air-dried indoors for 24 hours to obtain saturated surface-dry fine aggregates of river sand. The cement dosage per cubic meter of concrete was 460 kg / m 3 , fly ash replaced 20% of the cement, the water-binder ratio was 0.35, and the total aggregate amount was 1779 kg / m 3 , and the sand ratio was 39%. Detection was carried out according to the concrete mix proportion in Table 3.

[0077] Table 3

[0078]

[0079] Detection of the anti-clay performance of high-range water reducers: Put 368 kg of cement, 92 kg of fly ash, 693.81 kg of fine river sand aggregate, and 1085.2 kg of coarse aggregate into a vertical mixer and mix for 2 minutes at a stirring speed of 30 revolutions per minute. Then, add 161 kg of mixing water containing a high-range water reducer of organosilicon condensate type with phosphate groups, amino groups, and linear chains to the mixer and stir for 2 minutes at a stirring speed of 30 revolutions per minute. To avoid the mixture from accumulating at the bottom of the container, manually stir the slurry with a shovel twice. Finally, accelerate the mixing for 2 minutes at a stirring speed of 60 revolutions per minute to remove the air bubbles in the fresh concrete slurry, and measure the initial slump flow of the fresh concrete. Put the fresh concrete into a metal container, and re-measure the slump flow of the concrete after 30, 60, 90, and 120 minutes. After that, pour the fresh concrete into test molds of 100 mm×100 mm×100 mm and 150 mm×150 mm×550 mm, and place them indoors (temperature 25°C, humidity 55 - 65%) for 24 hours. After 1 day, remove the concrete containing the high-range water reducer of organosilicon condensate type with phosphate groups, amino groups, and linear chains from the test mold, and cure it in an environment with a temperature of 20°C and a humidity of 90±5% for 3, 7, and 28 days. Take 3 specimens of 100 mm×100 mm×100 mm and 150 mm×150 mm×550 mm to test the compressive strength and flexural strength of the concrete. By measuring the retention of the slump flow of the concrete containing the high-range water reducer of organosilicon condensate type with phosphate groups, amino groups, and linear chains and the mechanical properties of the concrete under different clay contents, evaluate the anti-clay effect of this high-range water reducer.

[0080] Figure 6 The following shows the change of the slump of the concrete containing the high-range water reducer of organosilicon condensate type with phosphate groups, amino groups, and linear chains with time under different clay contents. It can be seen from the figure that with the increase of the placement time, the fluidity of the concrete specimens with different clay contents all decreases. After two hours of placement, the concrete containing muddy fine aggregate has slightly worse slump retention than the blank concrete. With the increase of the clay content, the initial fluidity of the concrete decreases to a certain extent. The high-range water reducer of organosilicon condensate type with phosphate groups, amino groups, and linear chains has good anti-clay performance.

[0081] Figure 7 The following shows the change of the compressive strength of the concrete with the curing age under different clay contents. It can be seen from the figure that with the increase of the curing age, the compressive strength of the concrete containing fine aggregate with different clay contents all increases. At the same curing age, the concrete containing muddy fine aggregate has slightly lower compressive strength than the blank concrete. With the increase of the clay content in the fine aggregate, the compressive strength of the concrete decreases.

[0082] Figure 8The flexural strength of concrete with different mud contents varying with the curing age is shown. It can be seen from the figure that with the increase of the curing age, the flexural strength of concrete with fine aggregates with different mud contents increases. At the same curing age, the flexural strength of concrete with muddy fine aggregates is slightly lower than that of the blank concrete. With the increase of the mud content in the fine aggregates, the flexural strength of concrete decreases.

[0083] Example 6

[0084] Study on the corrosion resistance effect of high-performance water-reducing agents of organosilicon condensate type containing phosphate groups, amino groups and linear chains on steel bars in hardened concrete

[0085] Preparation of hardened reinforced concrete specimens: The evaluation of the corrosion resistance effect of high-performance water-reducing agents of organosilicon condensate type containing phosphate groups, amino groups and linear chains on steel bars adopts the hardened concrete method. The raw materials used in the test and the mix ratio of concrete are shown in the DEEPA-Si-SP-0 sample in Table 3. The dosage of sodium chloride in the concrete specimens is 0.35% of the cement dosage, and the dosages of high-performance water-reducing agents of organosilicon condensate type containing phosphate groups, amino groups and linear chains are 0.15%, 0.30%, 0.45% and 0.6% of the cement dosage. The concrete specimens containing high-performance water-reducing agents of organosilicon condensate type containing phosphate groups, amino groups and linear chains are prepared according to the method in Example 5, and the size of the specimens is 40mm×40mm×160mm. The treated steel bars are buried in the fresh concrete to form concrete electrodes. After the concrete electrodes are cured in the laboratory for 24h, they are demolded, and the exposed ends of the steel bars are covered with neat cement paste.

[0086] Curing of reinforced concrete with embedded steel bars and accelerated steel bar corrosion test: The concrete specimens with embedded steel bars are placed in a standard curing room for 28 days of curing. A wire of 130-150mm is welded to one end of the steel bar. The two ends of the specimen are coated with hot paraffin rosin for insulation, and the exposed length in the middle of the specimen is 80mm. Finally, the treated hardened concrete electrodes are immersed in a saturated calcium hydroxide solution for 4 hours. The anodic polarization potential values of the hardened reinforced concrete with embedded steel bars are measured at 2, 4, 6, 8, 10, 15, 20, 25 and 30 minutes by using a Corrtest corrosion electrochemistry test system, and a time-potential curve is made.

[0087] Rust inhibition effect of high-range water reducer on steel bars in hardened concrete specimens: Electrochemical tests were carried out by referring to the half-cell potential method of ASTM C 876 specification. The saturated calomel electrode was used as the reference electrode, and the steel bar was used as the auxiliary electrode. The Corrtest corrosion electrochemistry test system was used to measure the change of the natural electrode potential of the steel bar in the hardened concrete specimen with time, and to judge the electrochemical state of the steel bar in the hardened concrete. Before applying an external current during the test, the natural potential of the anode steel bar (i.e., the potential difference between the anode of the steel bar and the calomel electrode) was read out. After applying the external current, a polarization current of 50 μA / cm and a polarization time of 30 minutes were selected, and the anode polarization potential values at different polarization times were recorded.

[0088] Figure 9 The figure shows the change of the corrosion potential of steel bars in hardened concrete mixed with a high-range water reducer containing a phosphoric acid ester group, an amino group, and a linear silicone condensate with different dosages over time. It can be seen from the figure that within the same placement age, adding a high-range water reducer containing a phosphoric acid ester group, an amino group, and a linear silicone condensate can effectively increase the self-corrosion potential of the steel bars in the hardened concrete. The corrosion potential of the steel bars in the hardened concrete is closely related to the dosage of the high-range water reducer. With the increase in the dosage of the high-range water reducer containing a phosphoric acid ester group, an amino group, and a linear silicone condensate, the corrosion potential of the steel bars in the hardened concrete increases.

[0089] Through the above detection and invention of the performance of the prepared condensate-type high-range water reducer, adding this silicone condensate-type high-range water reducer to the aqueous solution can reduce the surface tension of the solution. This type of high-range water reducer has a good dispersing effect on cement particles and a protective effect on the steel bars of concrete, which proves that the phosphoric acid ester group is connected to the molecular chain of the water reducer. At the same time, the freshly mixed concrete added with this high-range water reducer also has good fluidity retention of the concrete, which indicates that an amino group is connected to the molecular chain of the water reducer. In addition, this condensate-type high-range water reducer improves the anti-clay effect of the high-range water reducer and prolongs the setting time of the concrete, which shows that the main chain of the high-range water reducer molecule contains a siloxane group. This indicates that negative groups such as phosphoric acid ester groups, amino groups, and siloxanes are connected to the molecule of the prepared condensate-type high-range water reducer.

Claims

1. A preparation method of a highly efficient water reducing agent of organosilicon polycondensate type, characterized in that, It includes the following steps: Step 1: Mix liquid ammonia, ethylene oxide and absolute ethanol, adjust the pH value of the solution to 7 - 8, raise the temperature for reaction to obtain a liquid of N - hydroxyethylamine compound; continue to adjust the pH value of the system to 9 - 10, dropwise add a quantitative formaldehyde solution, adjust the temperature for reaction to obtain an N - hydroxyethyl - N - hydroxymethylamine intermediate; Step 2: Prepare a chloroform solution containing phosphorus trichloride, mix it with the N - hydroxyethyl - N - hydroxymethylamine intermediate, dropwise add a triethylamine solution during the mixing process, raise the temperature for reaction; after the reaction, add a saturated sodium bicarbonate aqueous solution and continue the reaction until no bubbles are released from the product to obtain an amine - alcohol intermediate containing a phosphoester group; Step 3: Mix a di - hydrogen - terminated polydimethylsiloxane oligomer and the amine - alcohol intermediate containing a phosphoester group, adjust the pH value of the system to 11 - 12, raise the temperature for polymerization reaction to obtain a liquid of an organosilane - modified oligomer containing amino and phosphoester groups; Step 4: Adjust the pH of the solution of the linear organosilane - modified oligomer containing amino and phosphoester groups to 10 - 11 with sodium hydroxide, raise the temperature for dehydration condensation reaction to prepare an organosilicon condensate containing phosphoester groups, amino groups and linear chains; Step 5: Add a sodium hydroxide solution to the organosilicon condensate containing phosphoester groups, amino groups and linear chains, adjust the pH value of the system to 11 - 12, naturally cool to the ambient temperature, and cure in a reaction vessel to prepare a highly efficient water - reducing agent of the organosilicon condensate type; In the said Step 1, the mass ratio of liquid ammonia, ethylene oxide, absolute ethanol and formaldehyde solution is 6.4 - 6.5:2.4 - 2.5:4.8 - 5.0:11.5 - 12.0; in the said Step 2, the mass ratio of the chloroform solution of phosphorus trichloride, the N - hydroxyethyl - N - hydroxymethylamine intermediate and the saturated sodium bicarbonate aqueous solution is 32 - 33:20.5 - 21:5.25 - 5.30; among them, the specific preparation of the chloroform solution of phosphorus trichloride is: add 16 - 16.5 kg of phosphorus trichloride to every 32.0 - 33.0 kg of chloroform solution; in the said Step 3, the mass ratio of the di - hydrogen - terminated polydimethylsiloxane oligomer and the amine - alcohol intermediate containing a phosphoester group is 270 - 275:25 - 26.

2. The preparation method of the high-performance water reducer of silicone polycondensate type according to claim 1, characterized in that: In the said Step 1, the reaction temperature for the temperature - raising reaction is 60 - 70°C and the reaction time is 4 - 5 hours; the reaction temperature for the temperature - adjusting reaction is 40 - 45°C and the reaction time is 2 - 3 hours.

3. The preparation method of the high-performance water-reducing agent of the silicone polycondensate type according to claim 1, wherein: In the said Step 2, the reaction temperature for the temperature - raising reaction is 55 - 60°C and the reaction time is 5 - 6 hours; the reaction temperature for the continuous reaction is 30 - 35°C and the reaction time is 2 - 3 hours.

4. The preparation method of the organosilicon condensate type high-efficiency water reducing agent according to claim 1, characterized in that: In the said Step 3, the reaction temperature for the polymerization reaction is 80 - 85°C and the reaction time is 6 - 7 hours.

5. The preparation method of the organosilicon condensate type high-range water reducer according to claim 1, characterized in that: In the said Step 4, the reaction temperature for the dehydration condensation reaction is 90 - 95°C and the reaction time is 5 - 6 hours.

6. The preparation method of the organosilicon condensate type high-range water reducer according to claim 1, characterized in that: In the said Step 5, the weight - average molecular weight of the highly efficient water - reducing agent of the organosilicon condensate type is 12456 - 15471, the solid content is 23 - 30%, and the pH is 10 - 11.

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