A slow-release pour point depressant and water-reducing agent and its preparation method

Abstract

This invention discloses a slow-release depressant and water-reducing agent and its preparation method. Modified polycarboxylic acid, a modified carrier, and deionized water are mixed evenly. Under ultraviolet light irradiation, the mixture is stirred, filtered to remove the filtrate, and the filter cake is dried to obtain the slow-release depressant and water-reducing agent. This water-reducing agent contains a large number of ester groups. These ester groups hydrolyze in an alkaline environment, releasing macromolecules with dispersing effects, thus achieving a slow-release effect. The modified polycarboxylic acid side chains contain sulfonate and polyoxyethylene chain structures. Sulfonate can adsorb positively charged cement particles, while polyoxyethylene chains can bridge cement particles, increasing flocculation and thus delaying cement hydration. The modifier on the surface of the modified carrier contains a large number of hydroxyl groups, which can form complexes with calcium ions, forming a membrane on the surface. The membrane also contains cyclodextrin cavities, effectively isolating cement particles from contact, thereby achieving a retarding effect.

Description

Technical Field

[0001] This invention relates to the field of water-reducing agent preparation technology, specifically to a slow-release depressant water-reducing agent and its preparation method. Background Technology

[0002] Cement concrete is the primary material for modern highway bridges. Due to its wide availability, low cost, ease of production, and high compressive strength, good wear resistance, and wide range of strength grades, it is widely used in the machinery industry, marine development, geothermal engineering, and shipbuilding. However, significant seasonal temperature variations and the large differences in raw materials for concrete, coupled with the rapid slump loss of concrete mixes during transportation and construction, cause numerous problems for construction and quality control. Especially in the hot summer, the moisture in the concrete mix evaporates very easily during transportation and pumping. Over time, the moisture that provides lubrication gradually decreases, accelerating slump loss. Therefore, there is a pressing need for a water-reducing agent that can achieve a slow-release and de-setting effect. Summary of the Invention

[0003] The purpose of this invention is to provide a slow-release depressant water-reducing agent and its preparation method, which solves the problem of poor slow-release and depressant effects of current water-reducing agents.

[0004] The objective of this invention can be achieved through the following technical solutions:

[0005] A method for preparing a slow-release pour point depressant and water-reducing agent specifically includes the following steps:

[0006] The modified polycarboxylic acid, the modified carrier, and deionized water were mixed evenly and stirred for 1-1.5 hours under the conditions of 150-200 r / min and 365 nm ultraviolet light irradiation. The filtrate was then removed by filtration, and the filter cake was dried to obtain the slow-release decondensing water-reducing agent.

[0007] Furthermore, the mass ratio of the modified polycarboxylic acid to the modified carrier is 5-8:1.

[0008] Furthermore, the modified polycarboxylic acid is prepared by the following steps:

[0009] Step A1: Melamine is dissolved in ethanol, and nitrogen gas is introduced for protection. Under the conditions of 150-200 r / min, 25-30℃, and pH 9-10, polyethylene glycol diglycidyl ether is added while stirring. After reacting for 10-15 h, acrylic acid, intermediate 1, p-toluenesulfonic acid and DMF are mixed evenly. Under the conditions of 200-300 r / min and 100-110℃, the mixture is stirred and reacted for 3-5 h to obtain intermediate 2.

[0010] Step A2: Mix intermediate 2, acrylic acid, sodium methacrylate sulfonate, isopentenyl alcohol polyoxyethylene ether and deionized water evenly. Stir and add ammonium persulfate at a speed of 150-200 r / min and a temperature of 70-80℃ for 3-5 h to obtain intermediate 3. Mix intermediate 3, 2-mercaptoethanol, aluminum trichloride and DMF and react at a speed of 200-300 r / min and a temperature of 25-30℃ for 8-10 h to obtain modified polycarboxylic acid.

[0011] Furthermore, in step A1, the molar ratio of melamine and polyethylene glycol diglycidyl ether is n:2n+1, the molar ratio of acrylic acid and the hydroxyl group on intermediate 1 is 1:1, and the amount of p-toluenesulfonic acid is 3-5% of the mass of acrylic acid.

[0012] Furthermore, in step A2, the molar ratio of intermediate 2, acrylic acid, and isopentenyl alcohol polyoxyethylene ether is 1:3:12; the amount of sodium methacrylate sulfonate is 0.5% of the total mass of intermediate 2, acrylic acid, and isopentenyl alcohol polyoxyethylene ether; the amount of ammonium persulfate is 2% of the total mass of intermediate 2, acrylic acid, and isopentenyl alcohol polyoxyethylene ether; and the molar ratio of epoxy group, 2-mercaptoethanol, and aluminum trichloride on intermediate 3 is 1:1:0.02.

[0013] Furthermore, the modified carrier is prepared by the following steps:

[0014] Step B1: Add polyvinyl alcohol to deionized water and stir for 1-1.5 hours at a speed of 60-80 r / min and a temperature of 20-25℃. Then, raise the temperature to 90-95℃ and keep it at that temperature for 5-7 hours. Then, lower the temperature to 50-55℃, add epichlorohydrin and sodium hydroxide solution, and keep the pH at 10. React for 5-7 hours to obtain intermediate 4. Dissolve intermediate 4 in dimethyl sulfoxide, add acrylic acid, p-toluenesulfonic acid and toluene, and react for 3-5 hours at a speed of 120-150 r / min and a temperature of 100-110℃ to obtain the modifier.

[0015] Step B2: Disperse nano-silica in ethanol, add KH550 and deionized water, and react for 2-3 hours at a speed of 200-300 r / min and a temperature of 50-60℃ to obtain pretreated silica. Disperse mono-6-amino-6-deoxy-β-cyclodextrin and pretreated silica in ethanol, and stir and add glutaraldehyde dropwise at a speed of 150-200 r / min and a temperature of 40-45℃. After reacting for 4-6 hours, filter to remove the filtrate to obtain the pretreated carrier.

[0016] Step B3: Disperse the pretreated carrier in DMF, stir and add modifier under the conditions of 120-150 r / min, 30-35℃, and pH 9-10, and react for 6-8 h. After filtration to remove the filtrate, dry the filter cake to obtain the modified carrier.

[0017] Furthermore, in step B1, the amount of epichlorohydrin used is 1-1.5% of the mass of polyvinyl alcohol, the mass fraction of sodium hydroxide solution is 15%, the amount of acrylic acid used is 1-1.5% of the mass of intermediate 4, and the amount of p-toluenesulfonic acid used is 3-5% of the mass of acrylic acid.

[0018] Furthermore, the amount of KH550 used 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.

[0019] Furthermore, the mass ratio of the pretreatment carrier to the modifier in step B3 is 1:5.

[0020] The beneficial effects of this invention: The slow-release depressant and water-reducing agent disclosed in this invention is prepared by uniformly mixing modified polycarboxylic acid, a modified carrier, and deionized water, and then stirring under ultraviolet light irradiation. Under light irradiation, the thiol groups on the modified polycarboxylic acid react with the double bonds on the modified carrier, resulting in the modified polycarboxylic acid coating the surface of the modified carrier. The modified polycarboxylic acid reacts with melamine and polyethylene glycol diglycidyl ether under alkaline conditions, causing the amino groups on the melamine to react with the epoxy groups on the polyethylene glycol diglycidyl ether, forming an epoxy-terminated hyperbranched structure to obtain intermediate 1. Intermediate 1 and acrylic acid are then reacted with p-toluenesulfonic acid... Under the action of [agent / methacrylic acid], the hydroxyl groups on intermediate 1 and the carboxyl groups on acrylic acid are esterified to obtain intermediate 2. Intermediate 2, acrylic acid, sodium methacrylate sulfonate, and isopentenyl alcohol polyoxyethylene ether are polymerized to form hyperbranched polycarboxylic acid to obtain intermediate 3. Intermediate 3 and 2-mercaptoethanol are reacted under the action of aluminum trichloride to obtain modified polycarboxylic acid. The modified carrier is a polyvinyl alcohol used as a raw material and undergoes a ring-opening reaction with epichlorohydrin, followed by ring closure under alkaline conditions to form epoxy groups on the side chains of polyvinyl alcohol to obtain intermediate 4. Intermediate 4 and acrylic acid are reacted under the action of p-toluenesulfonic acid... The modifier is prepared by esterifying some of the hydroxyl groups on intermediate 4 and the carboxyl groups on acrylic acid. Nano-silica is treated with KH550 to graft active amino groups onto its surface. Mono-6-amino-6-deoxy-β-cyclodextrin and pretreated silica are dispersed in ethanol with glutaraldehyde to form a cyclodextrin-coated silica structure, thus preparing a pretreated carrier. The pretreated carrier and modifier are reacted under alkaline conditions, causing the epoxy groups on the surface of the modifier to react with the amino groups on the pretreated carrier, forming a modifier coating, thus preparing a modified carrier. This water-reducing agent contains a large number of ester groups, which hydrolyze under alkaline conditions, thereby releasing... The modified polycarboxylic acid has a dispersing effect, thus achieving a slow-release effect. The hyperbranched structure of the modified polycarboxylic acid increases the compatibility between the water-reducing agent and cement. At the same time, the side chain contains sulfonate and polyoxyethylene chain structures. The sulfonate can adsorb positively charged cement particles, and the polyoxyethylene chain can bridge cement particles, increasing the flocculation of cement particles and thus delaying cement hydration. The modifier on the surface of the modified carrier contains a large number of hydroxyl groups, which can form complexes with calcium ions to form a membrane on the surface. At the same time, the membrane contains cyclodextrin cavities, which effectively isolate the cement particles from contact with each other, thereby achieving a retarding effect. Detailed Implementation

[0021] The technical solutions in the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention. Example

[0022] A method for preparing a slow-release pour point depressant and water-reducing agent specifically includes the following steps:

[0023] Modified polycarboxylic acid, modified carrier, and deionized water were mixed evenly and stirred for 1 hour under the conditions of 150 r / min and 365 nm ultraviolet light irradiation. The filtrate was then removed by filtration, and the filter cake was dried to obtain a slow-release decondensing water-reducing agent.

[0024] The mass ratio of the modified polycarboxylic acid to the modified carrier is 5:1.

[0025] The modified polycarboxylic acid is prepared by the following steps:

[0026] Step A1: Melamine was dissolved in ethanol and protected with nitrogen gas. Under the conditions of 150 r / min, 25℃ and pH 9, polyethylene glycol diglycidyl ether was added and stirred for 10 h. Then, acrylic acid, intermediate 1, p-toluenesulfonic acid and DMF were mixed evenly and stirred for 3 h at 200 r / min and 100℃ to obtain intermediate 2.

[0027] Step A2: Mix intermediate 2, acrylic acid, sodium methacrylate sulfonate, isopentenyl alcohol polyoxyethylene ether and deionized water evenly. Stir and add ammonium persulfate at 150 r / min and 70°C for 3 h to obtain intermediate 3. Mix intermediate 3, 2-mercaptoethanol, aluminum trichloride and DMF and react at 200 r / min and 25°C for 8 h to obtain modified polycarboxylic acid.

[0028] The molar ratio of melamine and polyethylene glycol diglycidyl ether in step A1 is 1:3, the molar ratio of acrylic acid and the hydroxyl group on intermediate 1 is 1:1, the amount of p-toluenesulfonic acid is 3% of the mass of acrylic acid, and the molecular weight of polyethylene glycol diglycidyl ether is 500.

[0029] In step A2, the molar ratio of intermediate 2, acrylic acid, and isopentenyl alcohol polyoxyethylene ether is 1:3:12; the amount of sodium methacrylate sulfonate is 0.5% of the total mass of intermediate 2, acrylic acid, and isopentenyl alcohol polyoxyethylene ether; the amount of ammonium persulfate is 2% of the total mass of intermediate 2, acrylic acid, and isopentenyl alcohol polyoxyethylene ether; the molar ratio of epoxy group, 2-mercaptoethanol, and aluminum trichloride on intermediate 3 is 1:1:0.02; and the molecular weight of isopentenyl alcohol polyoxyethylene ether is 2400.

[0030] The modified carrier is prepared by the following steps:

[0031] Step B1: Polyvinyl alcohol is added to deionized water and stirred for 1 hour at 60 r / min and 20°C. Then, the temperature is raised to 90°C and kept at that temperature for 5 hours. The temperature is then lowered to 50°C, and epichlorohydrin and sodium hydroxide solution are added. The pH is maintained at 10, and the reaction is carried out for 5 hours to obtain intermediate 4. Intermediate 4 is dissolved in dimethyl sulfoxide, and acrylic acid, p-toluenesulfonic acid, and toluene are added. The reaction is carried out for 3 hours at 120 r / min and 100°C to obtain the modifier.

[0032] Step B2: Disperse nano-silica in ethanol, add KH550 and deionized water, and react for 2 hours at 200 r / min and 50℃ to obtain pretreated silica. Disperse mono-6-amino-6-deoxy-β-cyclodextrin and pretreated silica in ethanol, stir and add glutaraldehyde dropwise at 150 r / min and 40℃, and react for 4 hours. Filter to remove the filtrate to obtain the pretreated carrier.

[0033] Step B3: Disperse the pretreated carrier in DMF, stir and add modifier under the conditions of 120 r / min, 30℃, and pH 9, and react for 6 h. After filtration to remove the filtrate, dry the filter cake to obtain the modified carrier.

[0034] In step B1, the amount of epichlorohydrin used is 1% of the mass of polyvinyl alcohol, the mass fraction of sodium hydroxide solution is 15%, the amount of acrylic acid used is 1% of the mass of intermediate 4, the amount of p-toluenesulfonic acid used is 3% of the mass of acrylic acid, and the molecular weight of polyvinyl alcohol is 400.

[0035] The amount of KH550 used 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.

[0036] The mass ratio of the pretreatment carrier and the modifier in step B3 is 1:5. Example

[0037] A method for preparing a slow-release pour point depressant and water-reducing agent specifically includes the following steps:

[0038] Modified polycarboxylic acid, modified carrier, and deionized water were mixed evenly and stirred for 1.3 hours under 365nm ultraviolet light irradiation at a speed of 150 r / min. The filtrate was then removed by filtration, and the filter cake was dried to obtain a slow-release depressant and water-reducing agent.

[0039] The mass ratio of the modified polycarboxylic acid to the modified carrier is 6:1.

[0040] The modified polycarboxylic acid is prepared by the following steps:

[0041] Step A1: Melamine was dissolved in ethanol and protected with nitrogen gas. Under the conditions of 150 r / min, 28℃ and pH 10, polyethylene glycol diglycidyl ether was added and stirred. After reacting for 13 h, acrylic acid, intermediate 1, p-toluenesulfonic acid and DMF were mixed evenly and stirred for 4 h at 200 r / min and 105℃ to obtain intermediate 2.

[0042] Step A2: Mix intermediate 2, acrylic acid, sodium methacrylate sulfonate, isopentenyl alcohol polyoxyethylene ether and deionized water evenly. Stir and add ammonium persulfate at 200 r / min and 75°C for 4 h to obtain intermediate 3. Mix intermediate 3, 2-mercaptoethanol, aluminum trichloride and DMF and react at 200 r / min and 28°C for 9 h to obtain modified polycarboxylic acid.

[0043] The molar ratio of melamine to polyethylene glycol diglycidyl ether in step A1 is 2:5, the molar ratio of acrylic acid to the hydroxyl group on intermediate 1 is 1:1, the amount of p-toluenesulfonic acid is 4% of the mass of acrylic acid, and the molecular weight of polyethylene glycol diglycidyl ether is 500.

[0044] In step A2, the molar ratio of intermediate 2, acrylic acid, and isopentenyl alcohol polyoxyethylene ether is 1:3:12; the amount of sodium methacrylate sulfonate is 0.5% of the total mass of intermediate 2, acrylic acid, and isopentenyl alcohol polyoxyethylene ether; the amount of ammonium persulfate is 2% of the total mass of intermediate 2, acrylic acid, and isopentenyl alcohol polyoxyethylene ether; the molar ratio of epoxy group, 2-mercaptoethanol, and aluminum trichloride on intermediate 3 is 1:1:0.02; and the molecular weight of isopentenyl alcohol polyoxyethylene ether is 2400.

[0045] The modified carrier is prepared by the following steps:

[0046] Step B1: Polyvinyl alcohol was added to deionized water and stirred for 1.3 hours at 60 r / min and 23°C. The temperature was then raised to 93°C and held for 6 hours. The temperature was then lowered to 53°C, and epichlorohydrin and sodium hydroxide solution were added. The pH was maintained at 10, and the reaction was carried out for 6 hours to obtain intermediate 4. Intermediate 4 was dissolved in dimethyl sulfoxide, and acrylic acid, p-toluenesulfonic acid, and toluene were added. The reaction was carried out for 4 hours at 120 r / min and 105°C to obtain the modifier.

[0047] Step B2: Disperse nano-silica in ethanol, add KH550 and deionized water, and react for 3 h at a 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 add glutaraldehyde dropwise at a speed of 150 r / min and a temperature of 45 °C, and react for 5 h. Filter to remove the filtrate to obtain the pretreated carrier.

[0048] Step B3: Disperse the pretreated carrier in DMF, stir and add modifier under the conditions of 120 r / min, 33℃, and pH 10, and react for 7 h. After filtration to remove the filtrate, dry the filter cake to obtain the modified carrier.

[0049] In step B1, the amount of epichlorohydrin used is 1.5% of the mass of polyvinyl alcohol, the mass fraction of sodium hydroxide solution is 15%, the amount of acrylic acid used is 1.5% of the mass of intermediate 4, the amount of p-toluenesulfonic acid used is 4% of the mass of acrylic acid, and the molecular weight of polyvinyl alcohol is 400.

[0050] The amount of KH550 used 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.

[0051] The mass ratio of the pretreatment carrier and the modifier in step B3 is 1:5. Example

[0052] A method for preparing a slow-release pour point depressant and water-reducing agent specifically includes the following steps:

[0053] Modified polycarboxylic acid, modified carrier, and deionized water were mixed evenly and stirred for 1.5 hours under 365nm ultraviolet light irradiation at a speed of 200 r / min. The filtrate was then removed by filtration, and the filter cake was dried to obtain a slow-release decondensing water-reducing agent.

[0054] The mass ratio of the modified polycarboxylic acid to the modified carrier is 8:1.

[0055] The modified polycarboxylic acid is prepared by the following steps:

[0056] Step A1: Melamine was dissolved in ethanol and protected with nitrogen gas. Under the conditions of 200 r / min, 30℃ and pH 10, polyethylene glycol diglycidyl ether was added and stirred. After reacting for 15 h, acrylic acid, intermediate 1, p-toluenesulfonic acid and DMF were mixed evenly and stirred for 5 h at 300 r / min and 110℃ to obtain intermediate 2.

[0057] Step A2: Mix intermediate 2, acrylic acid, sodium methacrylate sulfonate, isopentenyl alcohol polyoxyethylene ether and deionized water evenly. Stir and add ammonium persulfate at 200 r / min and 80°C for 5 h to obtain intermediate 3. Mix intermediate 3, 2-mercaptoethanol, aluminum trichloride and DMF and react at 300 r / min and 30°C for 10 h to obtain modified polycarboxylic acid.

[0058] The molar ratio of melamine to polyethylene glycol diglycidyl ether in step A1 is 3:7, the molar ratio of acrylic acid to the hydroxyl group on intermediate 1 is 1:1, the amount of p-toluenesulfonic acid is 5% of the mass of acrylic acid, and the molecular weight of polyethylene glycol diglycidyl ether is 500.

[0059] In step A2, the molar ratio of intermediate 2, acrylic acid, and isopentenyl alcohol polyoxyethylene ether is 1:3:12; the amount of sodium methacrylate sulfonate is 0.5% of the total mass of intermediate 2, acrylic acid, and isopentenyl alcohol polyoxyethylene ether; the amount of ammonium persulfate is 2% of the total mass of intermediate 2, acrylic acid, and isopentenyl alcohol polyoxyethylene ether; the molar ratio of epoxy group, 2-mercaptoethanol, and aluminum trichloride on intermediate 3 is 1:1:0.02; and the molecular weight of isopentenyl alcohol polyoxyethylene ether is 2400.

[0060] The modified carrier is prepared by the following steps:

[0061] Step B1: Polyvinyl alcohol was added to deionized water and stirred for 1.5 hours at 80 r / min and 25°C. The temperature was then raised to 95°C and held for 7 hours. The temperature was then lowered to 55°C, and epichlorohydrin and sodium hydroxide solution were added. The pH was maintained at 10, and the reaction was carried out for 7 hours to obtain intermediate 4. Intermediate 4 was dissolved in dimethyl sulfoxide, and acrylic acid, p-toluenesulfonic acid, and toluene were added. The reaction was carried out for 5 hours at 150 r / min and 110°C to obtain the modifier.

[0062] Step B2: Disperse nano-silica in ethanol, add KH550 and deionized water, and react for 3 h at a 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 add glutaraldehyde dropwise at a speed of 200 r / min and a temperature of 45 °C, and react for 6 h. Filter to remove the filtrate to obtain the pretreated carrier.

[0063] Step B3: Disperse the pretreated carrier in DMF, stir and add modifier under the conditions of 150 r / min, 35℃, and pH 10, react for 8 h, filter to remove filtrate, dry the filter cake to obtain the modified carrier.

[0064] In step B1, the amount of epichlorohydrin used is 1.5% of the mass of polyvinyl alcohol, the mass fraction of sodium hydroxide solution is 15%, the amount of acrylic acid used is 1.5% of the mass of intermediate 4, the amount of p-toluenesulfonic acid used is 5% of the mass of acrylic acid, and the molecular weight of polyvinyl alcohol is 400.

[0065] The amount of KH550 used 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.

[0066] The mass ratio of the pretreatment carrier and the modifier in step B3 is 1:5.

[0067] Comparative Example 1

[0068] Compared with Example 1, in this comparative example, polyvinyl alcohol was dissolved in dimethyl sulfoxide, and acrylic acid, p-toluenesulfonic acid and toluene were added. The reaction was carried out for 3 hours at a rotation speed of 120 r / min and a temperature of 100°C. The reaction product obtained replaced the modified carrier, and the remaining steps were the same.

[0069] Comparative Example 2

[0070] Compared with Example 1, this comparative example uses modified polycarboxylate instead of the slow-release depressant and water-reducing agent.

[0071] Comparative Example 3

[0072] Compared with Example 1, this comparative example uses pretreated silica instead of the pretreated carrier, but the other steps are the same.

[0073] The water-reducing agents prepared in Examples 1-3 and Comparative Examples 1-3 were added to C30 concrete at a concentration of 0.22%. The slump of the concrete was tested at 0 min, 60 min, and 90 min according to GB / T50080-2002 standard, where the slump cone dimensions were 100 mm at the top, 200 mm at the bottom, and 300 mm in height. The flowability of the concrete paste was tested at 0 min, 60 min, and 90 min according to GB / T8077-2000 standard, where the truncated cone mold dimensions were 36 mm at the top, 60 mm at the bottom, and 80 mm in height, and the mold was a smooth, seamless stainless steel product. The test results are shown in the table below.

[0074]

[0075] As can be seen from the table above, the slump and flowability of the concrete treated by this application are better maintained.

[0076] The above description is merely an example and illustration of the concept of the present invention. Those skilled in the art can make various modifications or additions to the specific embodiments described or use similar methods to replace them, as long as they do not deviate from the concept of the invention or exceed the scope defined in the claims, they should all fall within the protection scope of the present invention.

Claims

1. A method for preparing a slow-release pour point depressant and water-reducing agent, characterized in that: Specifically, the steps include the following: Modified polycarboxylic acid, modified carrier and deionized water are mixed evenly, stirred under ultraviolet light irradiation, filtered to remove filtrate, and the filter cake is dried to obtain slow-release decondensing water-reducing agent. The modified polycarboxylic acid is prepared by the following steps: Step A1: Melamine is dissolved in ethanol, nitrogen gas is introduced for protection, and polyethylene glycol diglycidyl ether is added while stirring to carry out the reaction and obtain intermediate 1. Acrylic acid, intermediate 1, p-toluenesulfonic acid and DMF are mixed and reacted to obtain intermediate 2. Step A2: Mix and stir intermediate 2, acrylic acid, sodium methacrylate sulfonate, isopentenyl alcohol polyoxyethylene ether and deionized water, add ammonium persulfate, and react to obtain intermediate 3. Mix intermediate 3, 2-mercaptoethanol, aluminum trichloride and DMF to react to obtain modified polycarboxylic acid. The modified carrier is prepared by the following steps: Step B1: Polyvinyl alcohol is added to deionized water, stirred, heated and kept at a constant temperature, cooled and epichlorohydrin and sodium hydroxide solution are added to react and obtain intermediate 4. Intermediate 4 is dissolved in dimethyl sulfoxide, and acrylic acid, p-toluenesulfonic acid and toluene are added to react and obtain modifier. Step B2: Disperse nano-silica in ethanol, add KH550 and deionized water, and react to obtain pretreated silica. Disperse mono-6-amino-6-deoxy-β-cyclodextrin and pretreated silica in ethanol, stir and add glutaraldehyde dropwise, react, filter to remove filtrate, and obtain pretreated carrier. Step B3: Disperse the pretreated carrier in DMF, stir and add the modifier, react, filter to remove the filtrate, dry the filter cake to obtain the modified carrier.

2. The method for preparing a slow-release pour point depressant and water-reducing agent 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 method for preparing a slow-release pour point depressant and water-reducing agent according to claim 1, characterized in that: The molar ratio of melamine and polyethylene glycol diglycidyl ether in step A1 is n:2n+1, the molar ratio of acrylic acid and the hydroxyl group on intermediate 1 is 1:1, and the amount of p-toluenesulfonic acid is 3-5% of the mass of acrylic acid.

4. The method for preparing a slow-release pour point depressant and water-reducing agent according to claim 1, characterized in that: The molar ratio of intermediate 2, acrylic acid, and isopentenyl alcohol polyoxyethylene ether in step A2 is 1:3:

12. The amount of sodium methacrylate sulfonate is 0.5% of the total mass of intermediate 2, acrylic acid, and isopentenyl alcohol polyoxyethylene ether. The amount of ammonium persulfate is 2% of the total mass of intermediate 2, acrylic acid, and isopentenyl alcohol polyoxyethylene ether. The molar ratio of epoxy group, 2-mercaptoethanol, and aluminum trichloride on intermediate 3 is 1:1:0.

02.

5. The method for preparing a slow-release pour point depressant and water-reducing agent according to claim 1, characterized in that: In step B1, the amount of epichlorohydrin used is 1-1.5% of the mass of polyvinyl alcohol, the mass fraction of sodium hydroxide solution is 15%, the amount of acrylic acid used is 1-1.5% of the mass of intermediate 4, and the amount of p-toluenesulfonic acid used is 3-5% of the mass of acrylic acid.

6. The method for preparing a slow-release pour point depressant and water-reducing agent according to claim 1, characterized in that: The amount of KH550 used 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.

7. The method for preparing a slow-release pour point depressant and water-reducing agent according to claim 1, characterized in that: The mass ratio of the pretreatment carrier and the modifier in step B3 is 1:

5.

8. A slow-release pour point depressant and water-reducing agent, characterized in that: It is prepared by any one of the preparation methods according to claims 1-7.

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