Slow-release pour point depressing water reducing agent and preparation method thereof

Abstract

The preparation method comprises the following steps: uniformly mixing modified polycarboxylic acid, a modified carrier and deionized water, stirring under the condition of ultraviolet irradiation, filtering to remove filtrate, and drying a filter cake to prepare the slow-release pour-point-depressing water reducing agent, the water reducing agent contains a large amount of ester groups, the ester groups are hydrolyzed in an alkaline environment, and the water reducing agent has the advantages that the water reducing agent has a good water reducing effect; the side chain of the modified polycarboxylic acid contains sulfonate and polyoxyethylene chain structures, the sulfonate can adsorb cement particles with positive charges, and the polyoxyethylene chain can generate a bridging effect on the cement particles, so that the flocculation effect of the cement particles is improved, and the cement particles can be slowly released. The modifier on the surface of the modified carrier contains a large number of hydroxyl groups which can form a complex with calcium ions, a diaphragm is formed on the surface, and meanwhile, the diaphragm internally contains a cyclodextrin cavity, so that mutual contact among cement particles is effectively isolated, and the retarding effect is achieved.

Description

Technical Field

[0001] The present invention relates to the technical field of water reducer preparation, and specifically relates to a slow-release and coagulation-reducing water reducer and a preparation method thereof. Background Art

[0002] Cement concrete is the main material for today's highway bridges. Due to its wide source, low cost, easy production, and at the same time, it also has properties such as high compressive strength, good wear resistance, and a wide range of strength grades, it is widely used in the fields of mechanical industry, ocean development, and geothermal engineering including shipbuilding. Due to the prominent temperature changes in the four seasons and the large differences in concrete raw materials, at the same time, during the transportation and construction of concrete mixtures, the slump loss of concrete mixtures is too fast, bringing many troubles to engineering construction and adding many difficulties to the quality control of concrete mixtures. Especially in the hot summer, when transporting and pumping concrete, the water in the concrete mixture is very easy to evaporate. When the time is extended, the water providing lubrication will gradually decrease, accelerating the slump loss of concrete. Therefore, there is an urgent need for a water reducer that can achieve the effects of slow release and coagulation reduction. Summary of the Invention

[0003] The purpose of the present invention is to provide a slow-release and coagulation-reducing water reducer and a preparation method thereof, which solves the problem of poor slow-release effect and coagulation-reducing effect of water reducers at the present stage.

[0004] The purpose of the present invention can be achieved by the following technical solutions: A preparation method of a slow-release and coagulation-reducing water reducer specifically includes the following steps: Mix the modified polycarboxylic acid, modified carrier, and deionized water evenly, and under the conditions of a rotation speed of 150 - 200 r / min and ultraviolet light irradiation at 365 nm, stir for 1 - 1.5 h, then filter to remove the filtrate, and dry the filter cake to obtain the slow-release and coagulation-reducing water reducer.

[0005] Further, the mass ratio of the modified polycarboxylic acid to the modified carrier is 5 - 8:1.

[0006] Further, the modified polycarboxylic acid is prepared by the following steps: Step A1: Dissolve melamine in ethanol, introduce nitrogen protection, and under the conditions of a rotation speed of 150 - 200 r / min, a temperature of 25 - 30 °C, and a pH value of 9 - 10, stir and add polyethylene glycol diglycidyl ether, react for 10 - 15 h, then mix acrylic acid, intermediate 1, p-toluenesulfonic acid, and DMF evenly, and under the conditions of a rotation speed of 200 - 300 r / min and a temperature of 100 - 110 °C, stir and react for 3 - 5 h to obtain intermediate 2; Step A2: Mix intermediate 2, acrylic acid, sodium methallylsulfonate, isopentenol polyoxyethylene ether and deionized water evenly. Under the conditions of a rotation speed of 150 - 200 r / min and a temperature of 70 - 80 °C, stir and add ammonium persulfate, and carry out the reaction for 3 - 5 h to obtain intermediate 3. Mix intermediate 3, 2-mercaptoethanol, aluminum trichloride and DMF, and carry out the reaction for 8 - 10 h under the conditions of a rotation speed of 200 - 300 r / min and a temperature of 25 - 30 °C to obtain the modified polycarboxylic acid.

[0007] Further, the molar ratio of melamine to polyethylene glycol diglycidyl ether in step A1 is n:2n + 1, the molar ratio of acrylic acid to the hydroxyl groups on intermediate 1 is 1:1, and the dosage of p-toluenesulfonic acid is 3 - 5% of the mass of acrylic acid.

[0008] Further, the molar ratio of intermediate 2, acrylic acid and isopentenol polyoxyethylene ether in step A2 is 1:3:12, the dosage of sodium methallylsulfonate is 0.5% of the sum of the masses of intermediate 2, acrylic acid and isopentenol polyoxyethylene ether, the dosage of ammonium persulfate is 2% of the sum of the masses of intermediate 2, acrylic acid and isopentenol polyoxyethylene ether, and the molar ratio of the epoxy groups on intermediate 3, 2-mercaptoethanol and aluminum trichloride is 1:1:0.02.

[0009] Further, the modified carrier is prepared by the following steps: Step B1: Add polyvinyl alcohol to deionized water. Under the conditions of a rotation speed of 60 - 80 r / min and a temperature of 20 - 25 °C, stir for 1 - 1.5 h, then raise the temperature to 90 - 95 °C, keep warm for 5 - 7 h, cool down to 50 - 55 °C, add epichlorohydrin and sodium hydroxide solution, keep the pH value at 10, and carry out the reaction for 5 - 7 h to obtain intermediate 4. Dissolve intermediate 4 in dimethyl sulfoxide, add acrylic acid, p-toluenesulfonic acid and toluene, and carry out the reaction for 3 - 5 h under the conditions of a rotation speed of 120 - 150 r / min and a temperature of 100 - 110 °C to obtain the modifier; Step B2: Disperse nano-silica in ethanol, add KH550 and deionized water, and carry out the reaction for 2 - 3 h under the conditions of a rotation speed of 200 - 300 r / min and a temperature of 50 - 60 °C to obtain pretreated silica. Disperse mono-6-amino-6-deoxy-β-cyclodextrin and pretreated silica in ethanol, under the conditions of a rotation speed of 150 - 200 r / min and a temperature of 40 - 45 °C, stir and dropwise add glutaraldehyde, and carry out the reaction for 4 - 6 h, then filter to remove the filtrate to obtain the pretreated carrier; Step B3: Disperse the pretreated carrier in DMF, stir and add a modifier under the conditions of a rotation speed of 120 - 150 r / min, a temperature of 30 - 35 °C, and a pH value of 9 - 10. After reacting for 6 - 8 h, filter to remove the filtrate, and dry the filter cake to obtain the modified carrier.

[0010] Furthermore, the dosage of epichlorohydrin described in Step B1 is 1 - 1.5% of the mass of polyvinyl alcohol, the mass fraction of the sodium hydroxide solution is 15%, the dosage of acrylic acid is 1 - 1.5% of the mass of Intermediate 4, and the dosage of p-toluenesulfonic acid is 3 - 5% of the mass of acrylic acid.

[0011] Furthermore, the dosage of KH550 described in Step B2 is 3% of the mass of nano-silica, and the mass ratio of mono-6-amino-6-deoxy-β-cyclodextrin, pretreated silica, and glutaraldehyde is 5.25:1.33:1.28.

[0012] Furthermore, the mass ratio of the pretreated carrier to the modifier described in Step B3 is 1:5.

[0013] Advantages of the present invention: A sustained-release anti-clotting water reducer disclosed by the present invention is prepared by uniformly mixing a modified polycarboxylic acid, a modified carrier, and deionized water and then performing a stirring treatment under the condition of ultraviolet light irradiation. Under the light condition, the mercapto group on the modified polycarboxylic acid reacts with the double bond on the modified carrier, so that the modified polycarboxylic acid coats the surface of the modified carrier. The modified polycarboxylic acid reacts with melamine and polyethylene glycol diglycidyl ether under alkaline conditions, so that the amino group on the melamine reacts with the epoxy group on the polyethylene glycol diglycidyl ether to form a hyperbranched structure capped with epoxy groups, and intermediate 1 is prepared. Intermediate 1 and acrylic acid react under the action of p-toluenesulfonic acid, so that the hydroxyl group on intermediate 1 and the carboxyl group on acrylic acid are esterified to prepare intermediate 2. Intermediate 2, acrylic acid, sodium methallylsulfonate, and isopentenyl polyoxyethylene ether are polymerized to form a hyperbranched polycarboxylic acid, and intermediate 3 is prepared. Intermediate 3 and 2-mercaptoethanol react under the action of aluminum trichloride, so that the hydroxyl group on intermediate 3 and the mercapto group on 2-mercaptoethanol react to prepare the modified polycarboxylic acid. The modified carrier is prepared by subjecting polyvinyl alcohol as a raw material to a ring-opening reaction with epichlorohydrin and then performing a ring-closure reaction under alkaline conditions to form epoxy groups on the side chains of polyvinyl alcohol, and intermediate 4 is prepared. Intermediate 4 and acrylic acid react under the action of p-toluenesulfonic acid, so that some of the hydroxyl groups on intermediate 4 and the carboxyl group on acrylic acid are esterified to prepare a modifier. Nano-silica is treated with KH550 to graft active amino groups on the surface. Mono-6-amino-6-deoxy-β-cyclodextrin and pretreated silica are dispersed in ethanol and glutaraldehyde is added to form a structure in which cyclodextrin coats silica, and a pretreated carrier is prepared. The pretreated carrier and the modifier react under alkaline conditions, so that the epoxy groups on the surface of the modifier react with the amino groups on the pretreated carrier to form a modifier coating, and a modified carrier is prepared. A large number of ester groups are contained in this water reducer. The ester groups are hydrolyzed in an alkaline environment, and then macromolecules with a dispersing effect are released, so as to achieve the effect of sustained release. The modified polycarboxylic acid is a hyperbranched structure, which can increase the compatibility between the water reducer components and cement. At the same time, the side chain contains a sulfonate and a polyoxyethylene chain structure. The sulfonate can adsorb cement particles with a positive charge, and the polyoxyethylene chain can produce a bridging effect on the cement particles, increasing the flocculation effect of the cement particles, and thus delaying the hydration of the cement. A large number of hydroxyl groups are contained in the modifier on the surface of the modified carrier. The hydroxyl groups can form a complex with calcium ions, forming a diaphragm on the surface. At the same time, the diaphragm contains a cyclodextrin cavity inside, effectively isolating the mutual contact between the cement particles, so as to achieve the effect of retarding setting. Detailed implementation manners

[0014] The technical solutions in the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present invention. Example

[0015] A preparation method of a sustained-release pour point depressant and water reducer, specifically including the following steps: Mix the modified polycarboxylic acid, modified carrier and deionized water evenly. Under the conditions of a rotation speed of 150 r / min and ultraviolet light irradiation at 365 nm, after stirring for 1 h, filter to remove the filtrate, and dry the filter cake to obtain the sustained-release pour point depressant and water reducer.

[0016] The mass ratio of the modified polycarboxylic acid to the modified carrier is 5:1.

[0017] The modified polycarboxylic acid is prepared by the following steps: Step A1: Dissolve melamine in ethanol, protect it by introducing nitrogen. Under the conditions of a rotation speed of 150 r / min, a temperature of 25 °C, and a pH value of 9, stir and add polyethylene glycol diglycidyl ether. After reacting for 10 h, mix acrylic acid, intermediate 1, p-toluenesulfonic acid and DMF evenly. Under the conditions of a rotation speed of 200 r / min and a temperature of 100 °C, stir and react for 3 h to obtain intermediate 2; Step A2: Mix intermediate 2, acrylic acid, sodium methallylsulfonate, isopentenyl polyoxyethylene ether and deionized water evenly. Under the conditions of a rotation speed of 150 r / min and a temperature of 70 °C, stir and add ammonium persulfate, and react for 3 h to obtain intermediate 3. Mix intermediate 3, 2-mercaptoethanol, aluminum trichloride and DMF, and under the conditions of a rotation speed of 200 r / min and a temperature of 25 °C, react for 8 h to obtain the modified polycarboxylic acid.

[0018] In step A1, the molar ratio of melamine to polyethylene glycol diglycidyl ether is 1:3, the molar ratio of acrylic acid to the hydroxyl group on intermediate 1 is 1:1, the dosage of p-toluenesulfonic acid is 3% of the mass of acrylic acid, and the molecular weight of polyethylene glycol diglycidyl ether is 500.

[0019] In step A2, the molar ratio of intermediate 2, acrylic acid and isopentenyl polyoxyethylene ether is 1:3:12, the dosage of sodium methallylsulfonate is 0.5% of the sum of the masses of intermediate 2, acrylic acid and isopentenyl polyoxyethylene ether, the dosage of ammonium persulfate is 2% of the sum of the masses of intermediate 2, acrylic acid and isopentenyl polyoxyethylene ether, the molar ratio of the epoxy group on intermediate 3, 2-mercaptoethanol and aluminum trichloride is 1:1:0.02, and the molecular weight of isopentenyl polyoxyethylene ether is 2400.

[0020] The modified carrier is prepared by the following steps: Step B1: Add polyvinyl alcohol into deionized water. Under the conditions of a rotation speed of 60 r / min and a temperature of 20 °C, stir for 1 h, then raise the temperature to 90 °C, keep the temperature for 5 h, cool down to 50 °C, add epichlorohydrin and sodium hydroxide solution, maintain the pH value at 10, and react for 5 h to obtain intermediate 4. Dissolve intermediate 4 in dimethyl sulfoxide, add acrylic acid, p-toluenesulfonic acid and toluene, and react for 3 h under the conditions of a rotation speed of 120 r / min and a temperature of 100 °C to obtain a modifier. Step B2: Disperse nano-silica in ethanol, add KH550 and deionized water, and react for 2 h under the conditions of a rotation speed of 200 r / min and a temperature of 50 °C to obtain pretreated silica. Disperse mono-6-amino-6-deoxy-β-cyclodextrin and pretreated silica in ethanol, stir and dropwise add glutaraldehyde under the conditions of a rotation speed of 150 r / min and a temperature of 40 °C, and react for 4 h, then filter to remove the filtrate to obtain a pretreated carrier. Step B3: Disperse the pretreated carrier in DMF, stir and add the modifier under the conditions of a rotation speed of 120 r / min, a temperature of 30 °C, and a pH value of 9, react for 6 h, then filter to remove the filtrate, and dry the filter cake to obtain a modified carrier.

[0021] The dosage of epichlorohydrin in Step B1 is 1% of the mass of polyvinyl alcohol, the mass fraction of the sodium hydroxide solution is 15%, the dosage of acrylic acid is 1% of the mass of intermediate 4, the dosage of p-toluenesulfonic acid is 3% of the mass of acrylic acid, and the molecular weight of polyvinyl alcohol is 400.

[0022] The dosage of KH550 in Step B2 is 3% of the mass of nano-silica, and the mass ratio of mono-6-amino-6-deoxy-β-cyclodextrin, pretreated silica and glutaraldehyde is 5.25:1.33:1.48.

[0023] The mass ratio of the pretreated carrier and the modifier in Step B3 is 1:5. Example

[0024] A preparation method of a sustained-release pour point depressant and water reducer specifically includes the following steps: Mix the modified polycarboxylic acid, the modified carrier and deionized water evenly, stir and process for 1.3 h under the conditions of a rotation speed of 150 r / min and 365 nm ultraviolet light irradiation, then filter to remove the filtrate, and dry the filter cake to obtain a sustained-release pour point depressant and water reducer.

[0025] The mass ratio of the modified polycarboxylic acid and the modified carrier is 6:1.

[0026] The modified polycarboxylic acid is prepared by the following steps: Step A1: Dissolve melamine in ethanol, and pass nitrogen for protection. Under the conditions of a rotation speed of 150 r / min, a temperature of 28 °C, and a pH value of 10, stir and add polyethylene glycol diglycidyl ether. After reacting for 13 h, mix acrylic acid, intermediate 1, p-toluenesulfonic acid, and DMF evenly. Under the conditions of a rotation speed of 200 r / min and a temperature of 105 °C, stir and react for 4 h to obtain intermediate 2; Step A2: Mix intermediate 2, acrylic acid, sodium methallylsulfonate, isopentenyl alcohol polyoxyethylene ether, and deionized water evenly. Under the conditions of a rotation speed of 200 r / min and a temperature of 75 °C, stir and add ammonium persulfate, and react for 4 h to obtain intermediate 3. Mix intermediate 3, 2-mercaptoethanol, aluminum trichloride, and DMF, and under the conditions of a rotation speed of 200 r / min and a temperature of 28 °C, react for 9 h to obtain the modified polycarboxylic acid.

[0027] In step A1, the molar ratio of melamine to polyethylene glycol diglycidyl ether is 2:5, the molar ratio of acrylic acid to the hydroxyl groups on intermediate 1 is 1:1, the dosage of p-toluenesulfonic acid is 4% of the mass of acrylic acid, and the molecular weight of polyethylene glycol diglycidyl ether is 500.

[0028] In step A2, the molar ratio of intermediate 2, acrylic acid, and isopentenyl alcohol polyoxyethylene ether is 1:3:12, the dosage of sodium methallylsulfonate is 0.5% of the sum of the masses of intermediate 2, acrylic acid, and isopentenyl alcohol polyoxyethylene ether, the dosage of ammonium persulfate is 2% of the sum of the masses of intermediate 2, acrylic acid, and isopentenyl alcohol polyoxyethylene ether, the molar ratio of the epoxy groups on intermediate 3, 2-mercaptoethanol, and aluminum trichloride is 1:1:0.02, and the molecular weight of isopentenyl alcohol polyoxyethylene ether is 2400.

[0029] The modified carrier is prepared by the following steps: Step B1: Add polyvinyl alcohol to deionized water. Under the conditions of a rotation speed of 60 r / min and a temperature of 23 °C, stir for 1.3 h, then raise the temperature to 93 °C, keep warm for 6 h, cool down to 53 °C, add epichlorohydrin and sodium hydroxide solution, keep the pH value at 10, and react for 6 h to obtain intermediate 4. Dissolve intermediate 4 in dimethyl sulfoxide, add acrylic acid, p-toluenesulfonic acid, and toluene, and under the conditions of a rotation speed of 120 r / min and a temperature of 105 °C, react for 4 h to obtain the modifier; Step B2: Disperse nano-silica in ethanol, add KH550 and deionized water, and react for 3 h under the conditions of a rotation speed of 200 r / min and a temperature of 55 °C to obtain pretreated silica. Disperse mono-6-amino-6-deoxy-β-cyclodextrin and pretreated silica in ethanol, stir and dropwise add glutaraldehyde under the conditions of a rotation speed of 150 r / min and a temperature of 45 °C, and after reacting for 5 h, filter to remove the filtrate to obtain a pretreated carrier; Step B3: Disperse the pretreated carrier in DMF, stir and add a modifier under the conditions of a rotation speed of 120 r / min, a temperature of 33 °C, and a pH value of 10, and after reacting for 7 h, filter to remove the filtrate, and dry the filter cake to obtain a modified carrier.

[0030] The dosage of epichlorohydrin described in Step B1 is 1.5% of the mass of polyvinyl alcohol, the mass fraction of the sodium hydroxide solution is 15%, the dosage of acrylic acid is 1.5% of the mass of Intermediate 4, the dosage of p-toluenesulfonic acid is 4% of the mass of acrylic acid, and the molecular weight of polyvinyl alcohol is 400.

[0031] The dosage of KH550 described in Step B2 is 3% of the mass of nano-silica, and the mass ratio of mono-6-amino-6-deoxy-β-cyclodextrin, pretreated silica and glutaraldehyde is 5.25:1.33:1.48.

[0032] The mass ratio of the pretreated carrier and the modifier described in Step B3 is 1:5. Example

[0033] A preparation method of a sustained-release pour point depressant and water reducer specifically comprises the following steps: Mix the modified polycarboxylic acid, the modified carrier and deionized water evenly, stir and process for 1.5 h under the conditions of a rotation speed of 200 r / min and 365 nm ultraviolet light irradiation, then filter to remove the filtrate, and dry the filter cake to obtain the sustained-release pour point depressant and water reducer.

[0034] The mass ratio of the modified polycarboxylic acid and the modified carrier is 8:1.

[0035] The modified polycarboxylic acid is prepared by the following steps: Step A1: Dissolve melamine in ethanol, protect it by introducing nitrogen, stir and add polyethylene glycol diglycidyl ether under the conditions of a rotation speed of 200 r / min, a temperature of 30 °C, and a pH value of 10, and after reacting for 15 h, mix acrylic acid, Intermediate 1, p-toluenesulfonic acid and DMF evenly, and stir and react for 5 h under the conditions of a rotation speed of 300 r / min and a temperature of 110 °C to obtain Intermediate 2; Step A2: Mix intermediate 2, acrylic acid, sodium methallylsulfonate, isopentenol polyoxyethylene ether, and deionized water evenly. Under the conditions of a rotation speed of 200 r / min and a temperature of 80 °C, stir and add ammonium persulfate, and react for 5 h to obtain intermediate 3. Mix intermediate 3, 2-mercaptoethanol, aluminum trichloride, and DMF, and react for 10 h under the conditions of a rotation speed of 300 r / min and a temperature of 30 °C to obtain the modified polycarboxylic acid.

[0036] The molar ratio of melamine to polyethylene glycol diglycidyl ether described in Step A1 is 3:7, the molar ratio of acrylic acid to the hydroxyl groups on intermediate 1 is 1:1, the dosage of p-toluenesulfonic acid is 5% of the mass of acrylic acid, and the molecular weight of polyethylene glycol diglycidyl ether is 500.

[0037] The molar ratio of intermediate 2, acrylic acid, and isopentenol polyoxyethylene ether described in Step A2 is 1:3:12. The dosage of sodium methallylsulfonate is 0.5% of the sum of the masses of intermediate 2, acrylic acid, and isopentenol polyoxyethylene ether. The dosage of ammonium persulfate is 2% of the sum of the masses of intermediate 2, acrylic acid, and isopentenol polyoxyethylene ether. The molar ratio of the epoxy groups on intermediate 3, 2-mercaptoethanol, and aluminum trichloride is 1:1:0.02, and the molecular weight of isopentenol polyoxyethylene ether is 2400.

[0038] The modified carrier is prepared by the following steps: Step B1: Add polyvinyl alcohol to deionized water. Under the conditions of a rotation speed of 80 r / min and a temperature of 25 °C, stir for 1.5 h, then raise the temperature to 95 °C, keep the temperature for 7 h, cool down to 55 °C, add epichlorohydrin and sodium hydroxide solution, maintain the pH value at 10, and react for 7 h to obtain intermediate 4. Dissolve intermediate 4 in dimethyl sulfoxide, add acrylic acid, p-toluenesulfonic acid, and toluene, and react for 5 h under the conditions of a rotation speed of 150 r / min and a temperature of 110 °C to obtain the modifier. Step B2: Disperse nano-silica in ethanol, add KH550 and deionized water, and react for 3 h under the conditions of a rotation speed of 300 r / min and a temperature of 60 °C to obtain pretreated silica. Disperse mono-6-amino-6-deoxy-β-cyclodextrin and pretreated silica in ethanol, stir and dropwise add glutaraldehyde under the conditions of a rotation speed of 200 r / min and a temperature of 45 °C, react for 6 h, and then filter to remove the filtrate to obtain the pretreated carrier. Step B3: Disperse the pretreated carrier in DMF, stir and add the modifier under the conditions of a rotation speed of 150 r / min, a temperature of 35 °C, and a pH value of 10, react for 8 h, then filter to remove the filtrate, and dry the filter cake to obtain the modified carrier.

[0039] The dosage of epichlorohydrin described in step B1 is 1.5% of the mass of polyvinyl alcohol, the mass fraction of the sodium hydroxide solution is 15%, the dosage of acrylic acid is 1.5% of the mass of intermediate 4, the dosage of p-toluenesulfonic acid is 5% of the mass of acrylic acid, and the molecular weight of polyvinyl alcohol is 400.

[0040] The dosage of KH550 described in step B2 is 3% of the mass of nano-silica, and the mass ratio of mono-6-amino-6-deoxy-β-cyclodextrin, pretreated silica and glutaraldehyde is 5.25:1.33:1.48.

[0041] The mass ratio of the pretreated carrier to the modifier described in step B3 is 1:5.

[0042] Comparative Example 1 Compared with Example 1, in this comparative example, polyvinyl alcohol was dissolved in dimethyl sulfoxide, acrylic acid, p-toluenesulfonic acid and toluene were added, and the reaction was carried out at a rotation speed of 120 r / min and a temperature of 100 °C for 3 h. The obtained reaction product was used to replace the modified carrier, and the remaining steps were the same.

[0043] Comparative Example 2 Compared with Example 1, in this comparative example, modified polycarboxylic acid was used to replace the sustained-release pour point depressant and water reducer.

[0044] Comparative Example 3 Compared with Example 1, in this comparative example, pretreated silica was used to replace the pretreated carrier, and the remaining steps were the same.

[0045] The water reducers prepared in Examples 1-3 and Comparative Examples 1-3 were added to the concrete labeled C30 at 0.22%. According to the standard of GB / T50080-2002, the slump cone size was 100 mm at the upper opening, 200 mm at the lower opening and 300 mm in height. The slump of the concrete at 0 min, 60 min and 90 min was detected. According to the standard of GB / T8077-2000, the frustum cone mold specifications were 36 mm at the upper opening, 60 mm at the lower opening and 80 in height. It was a stainless steel product with a smooth inner wall and no seams. The net paste fluidity of the concrete at 0 min, 60 min and 90 min was detected. The test results are shown in the following table.

[0046]

[0047] As can be seen from the above table, the slump and net paste fluidity effects of the concrete treated in this application are better maintained.

[0048] The above content is only an example and illustration of the concept of the present invention. Those skilled in the art of this technology can make various modifications, supplements, or use similar methods to substitute for the specific embodiments described. As long as they do not deviate from the concept of the invention or exceed the scope defined by this claims, they should all fall within the protection scope of the present invention.

Claims

1. A preparation method of a sustained-release pour point depressant and water reducing agent, characterized in that: Specifically, it includes the following steps: Mix the modified polycarboxylic acid, modified carrier and deionized water evenly. Under the condition of ultraviolet light irradiation, after stirring treatment, filter to remove the filtrate, and dry the filter cake to obtain the sustained-release pour point depressant and water reducer.

2. The preparation method of a sustained-release pour point depressant and water reducer according to claim 1, characterized in that: The mass ratio of the modified polycarboxylic acid to the modified carrier is 5-8:

1.

3. The preparation method of a sustained-release pour point depressant and water reducer according to claim 1, characterized in that: The modified polycarboxylic acid is prepared by the following steps: Step A1: Dissolve melamine in ethanol, introduce nitrogen protection, stir and add polyethylene glycol diglycidyl ether. After reaction, mix and react acrylic acid, intermediate 1, p-toluenesulfonic acid and DMF to obtain intermediate 2; Step A2: Mix and stir intermediate 2, acrylic acid, sodium methallylsulfonate, isopentenyl polyoxyethylene ether and deionized water, and add ammonium persulfate. After reaction, obtain intermediate 3. Mix and react intermediate 3, 2-mercaptoethanol, aluminum trichloride and DMF to obtain the modified polycarboxylic acid.

4. The preparation method of a sustained-release pour point depressant and water reducer according to claim 3, characterized in that: In step A1, the molar ratio of melamine to polyethylene glycol diglycidyl ether is n:2n + 1, the molar ratio of acrylic acid to the hydroxyl group on intermediate 1 is 1:1, and the dosage of p-toluenesulfonic acid is 3-5% of the mass of acrylic acid.

5. The preparation method of a sustained-release pour point depressant and water reducer according to claim 3, characterized in that: In step A2, the molar ratio of intermediate 2, acrylic acid and isopentenyl polyoxyethylene ether is 1:3:12, the dosage of sodium methallylsulfonate is 0.5% of the sum of the masses of intermediate 2, acrylic acid and isopentenyl polyoxyethylene ether, the dosage of ammonium persulfate is 2% of the sum of the masses of intermediate 2, acrylic acid and isopentenyl polyoxyethylene ether, and the molar ratio of the epoxy group on intermediate 3, 2-mercaptoethanol and aluminum trichloride is 1:1:0.

02.

6. The preparation method of a sustained-release pour point depressant and water reducer according to claim 1, characterized in that: The modified carrier is prepared by the following steps: Step B1: Add polyvinyl alcohol to deionized water, stir, heat up and keep warm, cool down and add epichlorohydrin and sodium hydroxide solution, react to obtain intermediate 4. Dissolve intermediate 4 in dimethyl sulfoxide, add acrylic acid, p-toluenesulfonic acid and toluene, and react to obtain the modifier; Step B2: Disperse nano-silica in ethanol, add KH550 and deionized water, react to obtain pretreated silica. Disperse mono-6-amino-6-deoxy-β-cyclodextrin and pretreated silica in ethanol, stir and dropwise add glutaraldehyde. After reaction, filter to remove the filtrate to obtain the pretreated carrier; Step B3: Disperse the pretreated carrier in DMF, stir and add the modifier. After reaction, filter to remove the filtrate, and dry the filter cake to obtain the modified carrier.

7. The preparation method of a sustained-release pour point depressant and water reducer according to claim 6, characterized in that: In step B1, the dosage of epichlorohydrin is 1-1.5% of the mass of polyvinyl alcohol, the mass fraction of the sodium hydroxide solution is 15%, the dosage of acrylic acid is 1-1.5% of the mass of intermediate 4, and the dosage of p-toluenesulfonic acid is 3-5% of the mass of acrylic acid.

8. The preparation method of a sustained-release pour point depressant and water reducer according to claim 6, characterized in that: In step B2, the dosage of KH550 is 3% of the mass of nano-silica, and the mass ratio of mono-6-amino-6-deoxy-β-cyclodextrin, pretreated silica and glutaraldehyde is 5.25:1.33:1.

48.

9. The preparation method of a sustained-release pour point depressant and water reducer according to claim 6, characterized in that: In step B3, the mass ratio of the pretreated carrier to the modifier is 1:

5.

10. A sustained-release pour point depressant and water reducing agent, characterized in that: Prepared according to the preparation method described in any one of claims 1-9.

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