A low-sensitivity, high-slump-reducing polycarboxylic acid water-reducing agent and a preparation method thereof

Abstract

The present invention relates to the field of concrete admixtures, and specifically discloses a low-sensitivity high-slump-reducing polycarboxylic acid water-reducing agent and a preparation method thereof. The water-reducing agent includes the following components: 150 to 200 parts of polyether macromonomers, 5 to 10 parts of unsaturated ester monomers, 20 to 30 parts of unsaturated carboxylic acid monomers, 5 to 8 parts of homemade benzenesulfonic acid butenedioic acid monoester functional monomers, 8 to 10 parts of amide functional monomers, 1 to 3 parts of ferrous sulfate-hydrogen peroxide mixture, 0.5 to 1.5 parts of reducing agent, 0.4 to 0.9 parts of chain transfer agent, 3 to 6 parts of pH regulator, and dilution to 250 to 300 parts with water. The water-reducing agent can be directly applied to concrete with a relatively low dosage through molecular design, the interaction and synergy between chain segments and functional groups after polymerization of different monomers, and has good adaptability with each component in concrete, low sensitivity, can improve concrete anti-rebound and anti-cracking performance, and keep concrete at a high slump.

Description

Technical Field

[0001] The invention relates to the field of concrete admixtures, in particular to a low-sensitivity, high-slump-retention and shrinkage-reducing polycarboxylate water-reducing agent and a preparation method thereof. Background Art

[0002] Polycarboxylate water reducers improve the performance of concrete and have been widely used in recent years. However, in the process of concrete preparation, due to the complex variety of raw materials, the production process is also affected by factors such as fluctuations in the moisture content of sand and gravel, temperature changes, and the amount of admixture. In particular, at this stage, machine-made sand has been widely used instead of natural river sand. However, due to the limitations of production conditions, machine-made sand has problems such as unstable mud and powder content. The performance of concrete prepared with machine-made sand fluctuates greatly. If the existing polycarboxylate water reducer is directly used in concrete, there will be sensitivity problems such as poor adaptability of the water reducer to cement, sand and gravel, and mineral admixtures, easy segregation, easy rebound, or large slump loss, which cannot meet the requirements of engineering design.

[0003] The development of low-sensitivity, high-slump-retaining, shrinkage-reducing polycarboxylic acid water-reducing agent that is insensitive to cement, sand and gravel or machine-made sand, and mineral admixtures, and has good slump-retaining, anti-rebound, anti-cracking, and water-reducing effects, is of great significance to the widespread application of water-reducing agent in modern concrete building materials. Summary of the invention

[0004] In view of the above problems existing in the existing water reducers, the present invention provides a low-sensitivity, high-slump-retention polycarboxylic acid water reducer and a preparation method thereof. The water reducer can be directly applied to concrete at a relatively low dosage, has good adaptability to cement, sand and gravel, and mineral admixtures in the concrete, has low sensitivity, is resistant to rebound and cracking, and can maintain a relatively high slump.

[0005] In order to achieve the above-mentioned object of the invention, the present invention adopts the following technical solutions:

[0006] A low-sensitivity, high-slump-retention, polycarboxylic acid water-reducing agent, comprising the following components in parts by weight: 150-200 parts of polyether macromonomers, 5-10 parts of unsaturated ester monomers, 20-30 parts of unsaturated carboxylic acid monomers, 5-8 parts of benzenesulfonic acid butenedioic acid monoester functional monomers, 8-10 parts of amide functional monomers, 1-3 parts of ferrous sulfate-hydrogen peroxide mixture, 0.5-1.5 parts of reducing agent, 0.4-0.9 parts of chain transfer agent, 3-6 parts of pH regulator, diluted with water to 250-300 parts;

[0007] The preparation method of the benzenesulfonic acid butylene dicarboxylic acid monoester functional monomer comprises:

[0008] 4-Hydroxybenzenesulfonic acid and maleic anhydride are added to a solvent cyclohexane, and a superacid catalyst is added at the same time, mixed evenly, heated and stirred, and an esterification reaction is carried out at 70° C. to 80° C. under reflux. After the reaction is complete, the temperature is increased to evaporate and remove the solvent, and the product is naturally cooled to room temperature, and the product is washed and dried to obtain the benzenesulfonic acid maleic acid monoester functional monomer.

[0009] Compared with the prior art, the low-sensitivity, high-slump-retention, and shrinkage-reducing polycarboxylate water-reducing agent of the present invention has at least the following beneficial effects:

[0010] 1. The self-made benzenesulfonic acid butylated ester functional monomer of the present invention has a rigid benzene ring structure, can reduce concrete aggregation, can release carboxylic acid groups through late hydrolysis, and can further reduce sensitivity, reduce water and prevent collapse. In addition, the self-made benzenesulfonic acid butylated ester functional monomer of the present invention can directly and once add butylated anhydride to 4-hydroxybenzenesulfonic acid to increase the concentration of reactants, and carry out esterification reaction under the action of a superacid catalyst, which significantly improves the esterification reaction activity and the conversion rate of the product, and forms a monomer with the functions of reducing sensitivity and preventing collapse.

[0011] 2. The molecular structure of the water reducer designed by the present invention contains a benzene ring, a carboxyl group, an ester group, an amide group and a sulfonic acid group. In the initial stage of mixing with concrete, due to the negative electric repulsion between the carboxyl group and the concrete particles, plus the steric hindrance effect of the benzene ring in the functional monomer of benzenesulfonic acid butyl ester, the charge effect and the collapse-preserving effect of the sulfonic acid group, the water reducer has a higher initial water reduction rate and collapse-preserving property. In the later stage of concrete use, since the water reducer contains polyether macromonomer molecules, the compatibility and cohesion of the water reducer and concrete can be improved, the bond strength of the concrete components can be increased, the rebound rate can be reduced, and the shrinkage and cracking of the concrete can be avoided.

[0012] 3. The amide group contained in the water reducer can maintain a good negative charge balance, which helps to maintain the water reduction rate in the later stage. In addition, the water reducer molecule contains an ester structure that can be gradually hydrolyzed, which can be slowly hydrolyzed under alkaline conditions to produce carboxyl groups. The problem of sudden increase or decrease in concrete slump caused by too fast or too slow hydrolysis of the ester group will not occur. Therefore, the water reducer is not easily affected by changes in use conditions during use and can maintain a high concrete slump. This increases the stability and adaptability between the water reducer and the concrete components, reduces the sensitivity of the water reducer to cement, sand and gravel (machine-made sand), and mineral admixtures, improves the grip of the concrete components, and avoids the occurrence of concrete shrinkage and cracking. After the polycarboxylic acid water reducer provided by the present invention is combined with concrete, it can ensure that the concrete has low sensitivity, stability, good resistance to shrinkage, cracking resistance, and collapse retention, thereby improving the comprehensive performance of the concrete.

[0013] 4. The water reducer provided by the present invention has a polyether macromonomer added therein, which can increase the water film thickness on the surface of the cementitious material and the aggregate, and improve workability and working performance. After the polyether macromonomer is polymerized with the benzenesulfonic acid butyl ester functional monomer, a main chain structure containing a carboxyl group and a benzene ring structure, and a large number of highly active polyether and carboxylate side chain groups are formed in the water reducer system. Under the synergistic effect of the negative charge repulsion of the carboxyl group in the main chain structure, the rigid barrier structure of the benzene ring and the side chain groups, a double barrier effect is formed, which can reduce the adsorption and wrapping of water molecules, reduce the aggregation of concrete particles, improve the adsorption state of the cement particle surface, reduce sensitivity, reduce the rebound rate, avoid concrete cracking, and improve the water reduction and collapse resistance of concrete.

[0014] In one embodiment, the polyether macromonomer is at least one of 3-allylphenol polyoxyethylene polyoxypropylene ether, ethylene glycol monovinyl polyethylene glycol ether (EPEG) and ethoxyvinyl polyethylene glycol ether (VEPEG).

[0015] Among them, the preparation of the polyether macromonomer 3-allylphenol polyoxyethylene polyoxypropylene ether includes: adding a catalyst sodium ethoxide to 3-allylphenol, and under nitrogen protection, respectively adding ethylene oxide and propylene oxide to the mixed solution, controlling the reaction temperature at 120°C to 140°C, and performing the polymerization reaction for 2h to 3.5h. After the reaction is completed, cooling is performed to obtain the 3-allylphenol polyoxyethylene polyoxypropylene ether.

[0016] The preparation method is specifically as follows: add 0.05wt.% to 0.25wt.% of sodium ethoxide catalyst to 10wt.% to 25wt.% of 3-allylphenol by mass, and then add 30wt.% to 45wt.% of ethylene oxide and 20wt.% to 30wt.% of propylene oxide respectively under nitrogen protection, control the reaction temperature at 120°C to 140°C, perform the polymerization reaction for 2h to 3.5h, and cool to room temperature after the reaction to obtain a light yellow 3-allylphenol polyoxyethylene polyoxypropylene ether macromonomer.

[0017] In the molecular structure of the polyether macromonomer 3-allylphenol polyoxyethylene polyoxypropylene ether, phenol is directly connected to the allyl group, and through the conjugation effect and hyperconjugation effect between the CO single bond, the benzene ring and the carbon-carbon unsaturated double bond C=C, the C=C unsaturated double bond in the polyether macromonomer has a higher reaction activity and is more likely to undergo polymerization reaction. In addition, due to the steric hindrance effect of the benzene ring in the 3-allylphenol polyoxyethylene polyoxypropylene ether, the water reducer has a higher initial water reduction rate and slump retention. In the molecular structure of ethylene glycol monovinyl polyethylene glycol ether (EPEG) and ethoxyvinyl polyethylene glycol ether (VEPEG), the CO single bond is directly connected to the carbon-carbon unsaturated double bond C=C, and the electron cloud of the C=C unsaturated double bond is offset due to the hyperconjugation effect, so that the C=C unsaturated double bond in the polyether macromonomer has a higher reaction activity and is more likely to undergo polymerization reaction. Moreover, since the CO single bond is connected to the C=C unsaturated double bond, the side chain has a larger range of activity, which can effectively improve its wrapping and entanglement properties, so that the synthesized polycarboxylate water reducer has higher adaptability and reduces the sensitivity of the polycarboxylate water reducer. Especially for the situation of poor quality of sand and gravel and high mud content, 3-allylphenol polyoxyethylene polyoxypropylene ether and ethoxylated polyether macromonomer can effectively inhibit the adsorption of clay and polycarboxylate water reducer, further improving the adaptability of polycarboxylate water reducer to clay.

[0018] In one embodiment, the unsaturated ester monomer is a mixture of at least two of trimethylolpropane triacrylate, ethoxylated trimethylolpropane triacrylate, allyl caproate, allyl heptanoate, allyl phenoxyacetate, furfuryl methacrylate and polyethylene glycol methacrylate in equal amounts.

[0019] The unsaturated carboxylic acid ester monomers provided by the present invention all have the functions of reducing sensitivity and preventing collapse. Adding the unsaturated carboxylic acid ester monomers to the water reducer can further reduce the sensitivity of the water reducer and improve the comprehensive performance of the concrete.

[0020] In one embodiment, the unsaturated carboxylic acid monomer is a mixture of at least two of itaconic acid, 2-methyl-2-butenoic acid, 3-methylbutenoic acid, 2-methyl-2-pentenoic acid and fumaric acid in equal weight.

[0021] In one embodiment, the amide functional monomer is at least one of N,N-diallylacrylamide, N-allylformamide, N-allylacrylamide, N-hydroxymethylacrylamide and 2-acrylamide-2-methylpropanesulfonic acid.

[0022] The amide functional monomer provided by the present invention can improve the strength of concrete, reduce the viscosity of concrete, reduce the sensitivity of the water reducer to cement, machine-made sand, and mineral admixtures, and improve the anti-mud performance of concrete.

[0023] In one embodiment, the chain transfer agent is at least one of thioglycolic acid, thioglycolic acid and 3-mercaptopropionic acid.

[0024] In one embodiment, the reducing agent is at least one of Bruggolite-FF6, sodium sulfite and sodium hypophosphite.

[0025] In one embodiment, the pH regulator is industrial liquid alkali (sodium hydroxide solution) with a mass fraction of 25% to 40%.

[0026] In one embodiment, the mass ratio of ferrous sulfate to hydrogen peroxide in the ferrous sulfate-hydrogen peroxide mixture is (0.1-0.2):1.

[0027] In one of the embodiments, in the method for preparing the benzenesulfonic acid maleic acid monoester functional monomer, the mass parts of each raw material are: 100-150 parts of 4-hydroxybenzenesulfonic acid, 20-50 parts of maleic anhydride, 50-100 parts of cyclohexane, and 4-7 parts of superacid catalyst.

[0028] In one of the embodiments, during the preparation of the benzenesulfonic acid butylene dicarboxylic acid monoester functional monomer, an oil-water separator is connected to the reaction device. The oil-water separator can be used to timely extract the small molecule products produced in the reaction process, thereby promoting the reaction equilibrium to move in a positive direction, which is beneficial to accelerate the reaction speed and further improve the yield of the benzenesulfonic acid butylene dicarboxylic acid monoester functional monomer.

[0029] In one embodiment, the superacid catalyst is HND-31 solid superacid catalyst.

[0030] HND-31 solid superacid catalyst has a strong catalytic effect. Compared with conventional catalysts used in esterification reactions, such as concentrated sulfuric acid, p-toluenesulfonic acid and other protonic acids, it has a stronger catalytic efficiency and is added in a small amount, which can avoid the introduction of excessive impurities into the product and make the product esterification rate reach more than 99.6%.

[0031] In one embodiment, the stirring speed is 400 r / min to 500 r / min.

[0032] In one embodiment, the esterification reaction time is 3.5h to 5h.

[0033] In one embodiment, the temperature of the elevated temperature evaporation to remove the solvent is 85°C to 90°C.

[0034] The boiling point of solvent cyclohexane is 80.7°C. When removing the solvent, the temperature needs to be raised to a temperature higher than the boiling point of the solvent, that is, higher than 80.7°C. Raising the temperature to 85°C to 90°C can quickly remove the solvent without affecting the product.

[0035] In one embodiment, the washing is washing with water for 3 to 5 times.

[0036] In one embodiment, the drying is vacuum drying for 5 h to 6 h.

[0037] In the preparation process of the benzenesulfonic acid butylene ester functional monomer, by optimizing the key parameters in the process, including reaction temperature, reaction time and raw material addition amount, the prepared benzenesulfonic acid butylene ester functional monomer has a high yield and a simple preparation method, and can be widely used in the preparation of low-sensitivity, high-retention, collapse-reducing polycarboxylic acid water-reducing agent.

[0038] The present invention also provides a method for preparing the above-mentioned low-sensitivity high-slump-reducing polycarboxylate water-reducing agent, comprising the following steps:

[0039] Step a: adding 5 to 10 parts of unsaturated ester monomers, 5 to 7 parts of unsaturated carboxylic acid monomers and 1 to 3 parts of ferrous sulfate-hydrogen peroxide mixture into 10 to 20 parts of water, mixing and stirring, and then adding 5 to 8 parts of benzenesulfonic acid butenedioic acid monoester functional monomers and 8 to 10 parts of amide functional monomers into the mixed solution to obtain a functional monomer mixed solution;

[0040] Step b: adding 150 to 200 parts of polyether macromonomer to 30 to 50 parts of water, heating to 30° C. to 40° C., stirring and mixing to obtain a macromonomer aqueous solution;

[0041] Step c: Add 0.5-1.5 parts of a reducing agent and 0.4-0.9 parts of a chain transfer agent to the aqueous solution of the macromonomer obtained in step b, mix well, and then drip the functional monomer mixture obtained in step a, the dripping speed of the functional monomer mixture is 0.08mL / min-0.10mL / min, and after the dripping of the functional monomer mixture is completed, continue to drip the remaining unsaturated carboxylic acid monomer, the dripping speed of the unsaturated carboxylic acid monomer is 0.1mL / min-0.15mL / min, and control the reaction temperature to be 30°C-40°C. After the dripping of the unsaturated carboxylic acid monomer is completed, continue to stir, react for a period of time, add 3-6 parts of a pH adjuster, and after the reactants are aged and naturally cooled, dilute with water to 250-300 parts, mix well, and obtain the low-sensitivity, high-retention, collapse-reducing polycarboxylic acid water-reducing agent.

[0042] The present invention uses a redox system ferrous sulfate-hydrogen peroxide mixture to initiate polymerization, which has a fast initiation reaction speed and can initiate polymerization at a relatively low temperature. It can be understood that in the preparation process of the polycarboxylic acid water reducer, the raw materials used include the following components in mass fractions: 150 to 200 parts of polyether macromonomers, 5 to 10 parts of unsaturated ester monomers, 20 to 30 parts of unsaturated carboxylic acid monomers, 5 to 8 parts of benzenesulfonic acid butenedioic acid monoester functional monomers, 8 to 10 parts of amide functional monomers, 1 to 3 parts of ferrous sulfate-hydrogen peroxide mixture, 0.5 to 1.5 parts of reducing agent, 0.4 to 0.9 parts of chain transfer agent, 3 to 6 parts of pH adjuster, and dilute to 250 to 300 parts with water. In step a, 5 to 7 parts of unsaturated carboxylic acid monomers are used. The remaining unsaturated carboxylic acid monomers mentioned in step c refer to the total number of unsaturated carboxylic acid monomers minus the number of unsaturated carboxylic acid monomers used in step a. The remaining unsaturated carboxylic acid monomers are then added to the reaction system in a dropwise manner to carry out a polymerization reaction.

[0043] Compared with the prior art, the preparation method of the low-sensitivity high-slump-reducing polycarboxylate water-reducing agent of the present invention has at least the following beneficial effects:

[0044] 1. Polyether macromonomers are polymerized with unsaturated carboxylic acid monomers, benzenesulfonic acid butenedioic acid monoester functional monomers and amide functional monomers. Chain transfer agents can transfer chain growth free radicals, and polycarboxylic acid water reducers are obtained through free radical polymerization. The prepared polycarboxylic acid water reducer can achieve the effects of desensitization, water reduction, shrinkage reduction, crack resistance and collapse protection. While improving the strength and working performance of concrete, it can effectively increase the stability and adaptability between the water reducer and concrete components, reduce the sensitivity of the water reducer to cement, sandstone, and mineral admixtures, and improve the crack resistance and collapse protection of concrete.

[0045] 2. The addition time of unsaturated carboxylic acid monomers is longer than that of other monomers, in order to make the unsaturated carboxylic acid monomers evenly distributed in the water reducer chain. If the unsaturated carboxylic acid monomers are added too quickly, the polymerization will be accelerated, and gel effect and implosion will easily occur, which will affect the performance of the synthetic product and even cause the reaction to fail; while too slow a droplet acceleration will also lead to excessive average polymerization and cross-linking, which will reduce the product performance. Therefore, strictly controlling the droplet acceleration of unsaturated carboxylic acid monomers can make the reaction smooth and complete, and can make the average molecular weight distribution of the polymer narrower and the polymerization reaction more complete.

[0046] 3. The preparation method of the water reducing agent provided by the present invention is simple, easy, safe, reliable, highly operable, environmentally friendly, and the reaction process is easy to control, which has significant advantages in modern concrete construction applications.

[0047] In one embodiment, in step a, the stirring speed is 50 r / min to 60 r / min, and the stirring time is 5 min to 10 min.

[0048] In one embodiment, in step b, the stirring speed is 400 r / min to 500 r / min.

[0049] In one embodiment, in step c, after the unsaturated carboxylic acid monomer is added dropwise, the stirring speed is 300 r / min to 400 r / min, the reaction time is 2 h to 3 h, and the pH adjuster is added to adjust the pH to 6.0 to 7.0. DETAILED DESCRIPTION

[0050] In order to make the purpose, technical solution and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with the embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention.

[0051] In addition, the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Therefore, the features defined as "first" and "second" may explicitly or implicitly include at least one of the features. In the description of the invention, the meaning of "multiple" is at least two, such as two, three, etc., unless otherwise clearly and specifically defined. In the description of the present invention, the meaning of "several" is at least one, such as one, two, etc., unless otherwise clearly and specifically defined.

[0052] The words "preferably", "more preferably", etc. in the present invention refer to embodiments of the present invention that may provide certain beneficial effects in certain circumstances. However, other embodiments may also be preferred under the same circumstances or other circumstances. In addition, the description of one or more preferred embodiments does not imply that other embodiments are not applicable, nor is it intended to exclude other embodiments from the scope of the present invention.

[0053] When a numerical range is disclosed herein, the above range is considered to be continuous and includes the minimum and maximum values ​​of the range, as well as every value between such minimum and maximum values. Further, when a range refers to an integer, every integer between the minimum and maximum values ​​of the range is included. In addition, when multiple ranges are provided to describe features or characteristics, the ranges can be combined. In other words, unless otherwise indicated, all ranges disclosed herein should be understood to include any and all subranges included therein.

[0054] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as those commonly understood by those skilled in the art of the present invention. The terms used herein in the specification of the present invention are only for the purpose of describing specific embodiments and are not intended to limit the present invention. The term "and / or" used herein includes any and all combinations of one or more related listed items.

[0055] The following are specific examples. Unless otherwise specified, the raw materials used in the examples may be conventional commercial products in the art, or may be prepared by conventional methods in the art.

[0056] Example 1

[0057] A low-sensitivity, high-slump-retention, shrinkage-reducing polycarboxylate water-reducing agent, comprising the following components in parts by weight:

[0058] 150 parts of polyether macromonomer VEPEG, 5 parts of a mixture of trimethylolpropane triacrylate and polyethylene glycol methacrylate, with a mass ratio of 1:1; 20 parts of a mixture of itaconic acid and 2-methyl-2-butenoic acid, with a mass ratio of 1:1; 5 parts of homemade benzenesulfonic acid butenedioic acid monoester functional monomer, 8 parts of functional monomer N-allylformamide, 1 part of ferrous sulfate-hydrogen peroxide mixture, 0.5 parts of Bruggolite FF6 reducing agent, 0.4 parts of thioglycolic acid, 3 parts of 25% industrial liquid caustic soda, diluted to 250 parts with water.

[0059] The embodiment of the present invention provides a method for preparing a functional monomer of benzenesulfonic acid butenedioic acid monoester:

[0060] 100 g of 4-hydroxybenzenesulfonic acid and 20 g of maleic anhydride were added to 50 g of cyclohexane solution, and 4 g of commercial HND-31 solid superacid catalyst was added at the same time. After ultrasonic shaking and mixing, an oil-water separator was connected to the reaction device, and the mixture was heated and stirred at a stirring speed of 400 rpm. The esterification reaction was carried out at 70° C. under reflux for 3.5 h, and the cyclohexane solvent was evaporated and removed by heating to 90° C. After naturally cooling to room temperature, the mixture was washed with water 3 times and vacuum dried for 5 h to obtain a benzenesulfonic acid maleic acid monoester functional monomer.

[0061] The preparation method of the above-mentioned low-sensitivity high-slump-reducing polycarboxylic acid water-reducing agent comprises the following process steps:

[0062] Step a: adding 5 parts of a mixture of trimethylolpropane triacrylate and polyethylene glycol methacrylate in a mass ratio of 1:1, 5 parts of a mixture of itaconic acid and 2-methyl-2-butenoic acid in a mass ratio of 1:1, and 1 part of a ferrous sulfate-hydrogen peroxide mixture solution to 10 parts of water, mixing them thoroughly, stirring at a speed of 60 rpm for 5 minutes, and then adding 5 parts of a homemade benzenesulfonic acid butenedioic acid monoester functional monomer and 8 parts of N-allylformamide functional monomer to the above solution to obtain a functional monomer mixture;

[0063] Step b: Add 150 parts of VEPEG to 30 parts of water, heat to 30° C., and stir at 400 rpm to mix evenly to obtain a macromonomer aqueous solution;

[0064] Step c: Add 0.5 parts of Bruggolite FF6 and 0.4 parts of thioglycolic acid to the above-mentioned macromonomer aqueous solution, mix well, and then drip the functional monomer mixture in the above-mentioned step a at a dripping speed of 0.08 mL / min. After the dripping of the functional monomer mixture is completed, continue to drip the remaining 15 parts of itaconic acid and 2-methyl-2-butenoic acid mixture at a dripping speed of 0.1 mL / min, and control the reaction temperature at 30°C. After the dripping is completed, continue to stir the reaction at a speed of 300 rpm for 2 hours, then add 3 parts of 25% industrial liquid alkali, adjust the pH value to 6.0, and after the reactants are matured and naturally cooled, dilute with water to 250 parts, mix well, and obtain a low-sensitivity, high-retention, collapse-reducing polycarboxylic acid water-reducing agent.

[0065] Example 2

[0066] A low-sensitivity, high-slump-retention, shrinkage-reducing polycarboxylate water-reducing agent, comprising the following components in parts by weight:

[0067] 165 parts of polyether macromonomer 3-allylphenol polyoxyethylene polyoxypropylene ether, 7 parts of a mixture of allyl caproate and allyl heptanoate, in a mass ratio of 1:1; 23 parts of a mixture of 2-methyl-2-pentenoic acid and fumaric acid, in a mass ratio of 1:1; 6 parts of homemade benzenesulfonic acid butenedioic acid monoester functional monomer, 8.5 parts of functional monomer N-allylacrylamide, 1.5 parts of a ferrous sulfate-hydrogen peroxide mixture, 1.2 parts of sodium sulfite, 0.5 parts of thioglycolic acid, 4 parts of 35% industrial liquid caustic soda, diluted with water to 270 parts.

[0068] In this embodiment, the preparation method of the polyether macromonomer 3-allylphenol polyoxyethylene polyoxypropylene ether includes: adding 0.2wt.% of sodium ethanol catalyst to 20wt.% of 3-allylphenol by mass, and then adding 35wt.% of ethylene oxide and 25wt.% of propylene oxide by mass under nitrogen protection, respectively, controlling the reaction temperature to 130°C, the polymerization reaction for 3.0h, cooling after the reaction, and obtaining a light yellow 3-allylphenol polyoxyethylene polyoxypropylene ether macromonomer.

[0069] The embodiment of the present invention provides a method for preparing a functional monomer of benzenesulfonic acid butenedioic acid monoester:

[0070] 120g of 4-hydroxybenzenesulfonic acid and 30g of maleic anhydride are added to 65g of cyclohexane solution, and 5g of commercial HND-31 solid superacid catalyst is added at the same time. After ultrasonic vibration mixing, an oil-water separator is connected to the reaction device, and heating and stirring are performed at a stirring speed of 450 rpm. The esterification reaction is carried out at 75°C under reflux for 3.5h. The cyclohexane solvent is evaporated and removed by heating to 90°C. After naturally cooling to room temperature, the solution is washed with water 4 times and vacuum dried for 5.5h to obtain a benzenesulfonic acid maleic acid monoester functional monomer.

[0071] The preparation method of the above-mentioned low-sensitivity high-slump-reducing polycarboxylic acid water-reducing agent comprises the following process steps:

[0072] Step a: adding 7 parts of a mixture of allyl hexanoate and allyl heptanoate in a mass ratio of 1:1, 6 parts of a mixture of 2-methyl-2-pentenoic acid and fumaric acid in a mass ratio of 1:1, and 1.5 parts of a ferrous sulfate-hydrogen peroxide mixture solution to 15 parts of water, mixing them thoroughly, stirring at a speed of 60 rpm for 7 minutes, and then adding 6 parts of a homemade benzenesulfonic acid butenedioic acid monoester functional monomer and 8.5 parts of N-allylacrylamide functional monomer to the above solution to obtain a functional monomer mixture;

[0073] Step b: adding 165 parts of 3-allylphenol polyoxyethylene polyoxypropylene ether to 40 parts of water, heating to 30° C., stirring and mixing at a speed of 420 rpm to obtain a macromonomer aqueous solution;

[0074] Step c: Add 1.2 parts of sodium sulfite and 0.5 parts of thioglycolic acid to the above-mentioned aqueous solution of macromonomer, mix well, and then drip the functional monomer mixture in the above step a at a dripping speed of 0.09 mL / min. After the dripping of the functional monomer mixture is completed, continue to drip the remaining 17 parts of the mixture of 2-methyl-2-pentenoic acid and fumaric acid at a dripping speed of 0.12 mL / min, and control the reaction temperature at 35°C. After the dripping is completed, continue to stir the reaction at a speed of 350 rpm for 2.5 hours, then add 4 parts of 35% industrial liquid alkali, adjust the pH value to 6.5, and after the reactants are matured and naturally cooled, dilute with water to 270 parts, mix well, and obtain a low-sensitivity, high-retention, collapse-reducing polycarboxylic acid water-reducing agent.

[0075] Example 3

[0076] A low-sensitivity, high-slump-retention, shrinkage-reducing polycarboxylate water-reducing agent, comprising the following components in parts by weight:

[0077] 175 parts of polyether macromonomer EPEG, 8 parts of a mixture of allyl phenoxyacetate and furfuryl methacrylate, with a mass ratio of 1:1; 25 parts of a mixture of 2-methyl-2-butenoic acid and 3-methylbutenoic acid, with a mass ratio of 1:1; 6.5 parts of a homemade functional monomer of benzenesulfonic acid butenedioic acid monoester, 8.5 parts of a functional monomer 2-acrylamide-2-methylpropanesulfonic acid, 2 parts of a ferrous sulfate-hydrogen peroxide mixture, 1.3 parts of sodium hypophosphite, 0.6 parts of 3-mercaptopropionic acid, 5 parts of 40% industrial liquid caustic soda, diluted to 290 parts with water;

[0078] The embodiment of the present invention provides a method for preparing a functional monomer of benzenesulfonic acid butenedioic acid monoester:

[0079] 130 g of 4-hydroxybenzenesulfonic acid and 40 g of maleic anhydride were added to 80 g of cyclohexane solution, and 6.5 g of commercial HND-31 solid superacid catalyst was added at the same time. After ultrasonic shaking and mixing, an oil-water separator was connected to the reaction device, and the mixture was heated and stirred at a stirring speed of 480 rpm. The esterification reaction was carried out at 80° C. under reflux for 4 h, and the cyclohexane solvent was evaporated and removed by heating to 90° C. After naturally cooling to room temperature, the mixture was washed with water 5 times and vacuum dried for 6 h to obtain a benzenesulfonic acid maleic acid monoester functional monomer.

[0080] The preparation method of the above-mentioned low-sensitivity high-slump-reducing polycarboxylic acid water-reducing agent comprises the following process steps:

[0081] Step a: adding 8 parts of a mixture of allyl phenoxyacetate and furfuryl methacrylate in a mass ratio of 1:1, 7 parts of a mixture of 2-methyl-2-butenoic acid and 3-methylbutenoic acid in a mass ratio of 1:1, and 2 parts of a ferrous sulfate-hydrogen peroxide mixture solution to 18 parts of water, mixing them thoroughly, stirring at a speed of 60 rpm for 9 minutes, and then adding 6.5 parts of a homemade benzenesulfonic acid butenedioic acid monoester functional monomer and 8.5 parts of 2-acrylamide-2-methylpropanesulfonic acid functional monomer to the above solution to obtain a functional monomer mixture;

[0082] Step b: Add 175 parts of EPEG to 45 parts of water, heat to 30° C., and stir at 420 rpm to obtain a macromonomer aqueous solution;

[0083] Step c: Add 1.3 parts of sodium hypophosphite and 0.6 parts of 3-mercaptopropionic acid to the above-mentioned macromonomer aqueous solution, mix well, and then drip the functional monomer mixture in the above-mentioned step a at a dripping speed of 0.1 mL / min. After the functional monomer mixture is dripped, continue to drip the remaining 18 parts of 2-methyl-2-butenoic acid and 3-methylbutenoic acid mixture at a dripping speed of 0.13 mL / min, and control the reaction temperature at 35°C. After the dripping is completed, continue to stir the reaction at a speed of 380 rpm for 3 hours, then add 5 parts of 40% industrial liquid alkali, adjust the pH value to 7.0, and after the reactants are matured and naturally cooled, dilute with water to 270 parts, mix well, and obtain a low-sensitivity, high-retention, collapse-reducing polycarboxylic acid water-reducing agent.

[0084] Example 4

[0085] A low-sensitivity, high-slump-retention, shrinkage-reducing polycarboxylate water-reducing agent, comprising the following components in parts by weight:

[0086] 200 parts of polyether macromonomer 3-allylphenol polyoxyethylene polyoxypropylene ether, 10 parts of a mixture of polyethylene glycol methacrylate and allyl heptanoate, in a mass ratio of 1:1; 30 parts of a mixture of itaconic acid and 2-methyl-2-pentenoic acid, in a mass ratio of 1:1; 8 parts of homemade benzenesulfonic acid butenedioic acid monoester functional monomer, 10 parts of a mixture of N-allylformamide and N-allylacrylamide in a mass ratio of 1:1, 3 parts of a ferrous sulfate-hydrogen peroxide mixture, 1.5 parts of Bruggolite FF6 reducing agent, 0.9 parts of thioglycolic acid, 6 parts of 30% industrial liquid caustic soda, diluted to 300 parts with water;

[0087] In this embodiment, the preparation method of the polyether macromonomer 3-allylphenol polyoxyethylene polyoxypropylene ether includes: adding 0.25wt.% of sodium ethanol catalyst to 25wt.% of 3-allylphenol by mass, and then adding 45wt.% of ethylene oxide and 30wt.% of propylene oxide by mass under nitrogen protection, respectively, controlling the reaction temperature to 140°C, and polymerizing for 3.5h. After the reaction is completed, the temperature is lowered to obtain a light yellow 3-allylphenol polyoxyethylene polyoxypropylene ether macromonomer.

[0088] The present invention provides a method for preparing a functional monomer of benzenesulfonic acid butenedioic acid monoester:

[0089] 150g of 4-hydroxybenzenesulfonic acid and 50g of maleic anhydride are added to 100g of cyclohexane solution, and 7g of commercial HND-31 solid superacid catalyst is added at the same time. After ultrasonic vibration mixing, an oil-water separator is connected to the reaction device, and heating and stirring are performed at a stirring speed of 500 rpm. The esterification reaction is carried out at 80°C under reflux for 5h, and the cyclohexane solvent is evaporated and removed by heating to 90°C. After naturally cooling to room temperature, the mixture is washed with water 5 times and vacuum dried for 6h to obtain a benzenesulfonic acid maleic acid monoester functional monomer.

[0090] The preparation method of the above-mentioned low-sensitivity high-slump-reducing polycarboxylic acid water-reducing agent comprises the following process steps:

[0091] Step a: adding 10 parts of a mixture of polyethylene glycol methacrylate and allyl heptanoate in a mass ratio of 1:1, 7 parts of a mixture of itaconic acid and 2-methyl-2-pentenoic acid, and 3 parts of a ferrous sulfate-hydrogen peroxide mixture solution to 20 parts of water, mixing them thoroughly, and stirring at a speed of 60 rpm for 10 minutes, and then adding 8 parts of a homemade benzenesulfonic acid butenedioic acid monoester functional monomer and 10 parts of a mixture of N-allyl formamide and N-allyl acrylamide to the above solution to obtain a functional monomer mixture;

[0092] Step b: Add 200 parts of 3-allylphenol polyoxyethylene polyoxypropylene ether to 50 parts of water, heat to 30° C., and stir and mix at a speed of 500 rpm to obtain a macromonomer aqueous solution;

[0093] Step c: Add 1.5 parts of Bruggolite FF6 and 0.9 parts of thioglycolic acid to the above-mentioned macromonomer aqueous solution, mix well, and then drip the functional monomer mixture in the above-mentioned step a at a dripping speed of 0.1 mL / min. After the dripping of the functional monomer mixture is completed, continue to drip the remaining 23 parts of itaconic acid and 2-methyl-2-pentenoic acid mixture at a dripping speed of 0.15 mL / min, and control the reaction temperature at 40°C. After the dripping is completed, continue to stir the reaction at a speed of 400 rpm for 3 hours, then add 6 parts of 30% industrial liquid alkali, adjust the pH value to 7.0, and after the reactants are matured and naturally cooled, dilute with water to 300 parts, mix well, and obtain a low-sensitivity, high-retention, collapse-reducing polycarboxylic acid water-reducing agent.

[0094] Example 5

[0095] A low-sensitivity, high-slump-retention, shrinkage-reducing polycarboxylate water-reducing agent, comprising the following components in parts by weight:

[0096] 185 parts of polyether macromonomer ethoxyvinyl polyethylene glycol ether (VEPEG), 8 parts of a mixture of polyethylene glycol methacrylate and allyl heptanoate, in a mass ratio of 1:1; 18 parts of a mixture of 2-methyl-2-pentenoic acid and fumaric acid, 6 parts of a homemade functional monomer of benzenesulfonic acid butenedioic acid monoester, 9 parts of a mixture of N,N-diallylacrylamide and 2-acrylamide-2-methylpropanesulfonic acid in a mass ratio of 1:1, 1.5 parts of a ferrous sulfate-hydrogen peroxide mixture, 0.9 parts of a Bruggolite FF6 reducing agent, 0.6 parts of thioglycolic acid, 5 parts of 30% industrial liquid caustic soda, diluted to 300 parts with water;

[0097] The present invention provides a method for preparing a functional monomer of benzenesulfonic acid butenedioic acid monoester:

[0098] 135 g of 4-hydroxybenzenesulfonic acid and 38 g of maleic anhydride were added to 100 g of cyclohexane solution, and 6 g of commercial HND-31 solid superacid catalyst was added at the same time. After ultrasonic shaking and mixing, an oil-water separator was connected to the reaction device, and the mixture was heated and stirred at a stirring speed of 500 rpm. The esterification reaction was carried out at 75° C. under reflux for 4.5 h, and the cyclohexane solvent was evaporated and removed by heating to 85° C. After naturally cooling to room temperature, the mixture was washed with water 4 times and vacuum dried for 5 h to obtain a benzenesulfonic acid maleic acid monoester functional monomer.

[0099] The preparation method of the above-mentioned low-sensitivity high-slump-reducing polycarboxylic acid water-reducing agent comprises the following process steps:

[0100] Step a: adding 8 parts of a mixture of polyethylene glycol methacrylate and allyl heptanoate in a mass ratio of 1:1, 8 parts of a mixture of 2-methyl-2-pentenoic acid and fumaric acid in a mass ratio of equal parts, and 1.5 parts of a ferrous sulfate-hydrogen peroxide mixture solution to 20 parts of water, mixing them thoroughly, and stirring at a speed of 50 rpm for 8 minutes, and then adding 6 parts of a homemade benzenesulfonic acid butenedioic acid monoester functional monomer and 9 parts of a mixture of N,N-diallylacrylamide and 2-acrylamide-2-methylpropanesulfonic acid in a mass ratio of 1:1 to the above solution to obtain a functional monomer mixture;

[0101] Step b: adding 185 parts of VEPEG to 40 parts of water, heating to 40° C., stirring and mixing at a speed of 450 rpm to obtain a macromonomer aqueous solution;

[0102] Step c: Add 0.9 parts of Bruggolite FF6 and 0.6 parts of thioglycolic acid to the above-mentioned macromonomer aqueous solution, mix well, and then drip the functional monomer mixture in the above-mentioned step a at a dripping speed of 0.1 mL / min. After the functional monomer mixture is dripped, continue to drip the remaining 10 parts of 2-methyl-2-pentenoic acid and fumaric acid in equal weight at a dripping speed of 0.15 mL / min, and control the reaction temperature to 35°C. After the dripping is completed, continue to stir the reaction at a speed of 400 rpm for 2.5 hours, then add 5 parts of 30% industrial liquid alkali, adjust the pH value to 7.0, and after the reactants are matured and naturally cooled, dilute with water to 300 parts, mix well, and obtain a low-sensitivity, high-retention, collapse-reducing polycarboxylic acid water-reducing agent.

[0103] Application Example 1

[0104] The test was carried out according to the national standard GB / T50080-2011 "Standard for Test Methods of Ordinary Concrete Mixtures" and the standards JTG / T3650-2020 and GB / T17671 for "Technical Specifications for Highway Bridge and Culvert Construction". The compressive strength of concrete was tested in accordance with GB / T 50081-2019 "Standard for Test Methods of Physical and Mechanical Properties of Ordinary Concrete". The cements are Dinglu Cement PO 42.5, Conch Cement PO 42.5R, Taiwan Cement PO 42.5R and national standard cement; the sand is machine-made sand with a fineness modulus of 2.9 and river sand with a fineness modulus of 2.7; the gravel is crushed stone with a continuous grading of 5mm to 32.5mm; the fly ash is grade II and the mineral powder is grade S95. The admixtures used are low-sensitivity, high-retention, slump-reducing polycarboxylate water-reducing agent with a solid content of 40 wt.% prepared by the present invention and ST-03A polycarboxylate water-reducing agent with a solid content of 40 wt.% (produced by Liaoning Kelong Fine Chemical Co., Ltd.), and the admixture amount is 0.2 wt.% of the total mass of the cementitious material. The test is carried out according to the following mix ratio: cement: fly ash: mineral powder: machine-made sand (including river sand): gravel: water: admixture = 240: 60: 80: 777: 988: 195: 7.8 (unit: kg / m 3 ), the test results are shown in Table 1.

[0105] Table 1 Test results

[0106]

[0107]

[0108] As shown in Table 1, the water reducer provided by the embodiment of the present invention has a pressure water seepage rate of less than 5.1% and a water reduction rate of more than 37% under low dosage conditions. The concrete has a certain free expansion rate and has a significant anti-volume shrinkage effect. Moreover, the concrete mixed with the water reducer prepared by the embodiment of the present invention has a 2h slump loss of less than 3.0%, and the 7-day and 28-day compressive strengths are significantly higher than the concrete mixed with the ordinary commercial water reducer, which further illustrates that the concrete mixed with the water reducer prepared by the embodiment of the present invention has high water retention, shrinkage reduction and crack resistance. The introduction of the self-made 3-allylphenol polyoxyethylene polyoxypropylene ether macromonomer and the used ethylene glycol monovinyl polyethylene glycol ether, ethoxy vinyl polyethylene glycol ether macromonomer, and the self-made benzenesulfonic acid butyl ester functional monomer, the design of the water reducer molecular chain, the interaction and synergistic effect between various groups, increase the spatial effect of cement particles, the charge effect, so that the admixture exhibits good adaptability, slump retention, shrinkage reduction and excellent mechanical properties.

[0109] Application Example 2

[0110] Determination of the adaptability of water reducing agent to different cements

[0111] In order to study the sensitivity of the low-sensitivity, high-slump-retention, shrinkage-reducing polycarboxylate water-reducing agent prepared in the embodiment of the present invention to different cements, silicate cement produced by different manufacturers was selected to carry out concrete performance tests. The experimental results are shown in Table 2.

[0112] Table 2 Sensitivity of the example water reducer and existing water reducer to different cements

[0113]

[0114] As can be seen from Table 2, although the water-reducing agent prepared in the embodiment of the present invention has certain differences in the effects on the slump and expansion of concrete mixed with different types of cement, the 2h slump loss of the concrete prepared in Examples 1 to 5 is less than 3.1%, while the slump loss of the concrete mixed with the existing commercial water-reducing agent is as high as 20% or more, and the expansion of the concrete in the embodiment of the present invention is also maintained at a high level. The overall change trend is consistent, indicating that the low-sensitivity and high-retention slump-reducing polycarboxylate water-reducing agent prepared in the present invention has good adaptability and anti-sensitivity to different cements.

[0115] Application Example 3

[0116] Test on the sensitivity of water reducing agent to the amount of machine-made sand and ambient temperature

[0117] Under the same conditions, the percentage of machine-made sand in the total sand and gravel was adjusted to study the effect of water reducer on the slump and expansion of concrete at different machine-made sand dosages and different ambient temperatures. The results are shown in Table 3.

[0118] Table 3 Test results of sensitivity of water reducer to machine-made sand content and temperature

[0119]

[0120] As can be seen from Table 3, with the increase of the amount of machine-made sand, the slump loss of concrete also increases accordingly. Compared with the existing common commercial polycarboxylate water-reducing agent, the concrete slump loss and expansion difference of the water-reducing agent prepared by the embodiment of the present invention are very small, showing low sensitivity to the change of the content of machine-made sand. It can also be seen from the data in Table 3 that the slump loss of the water-reducing agent in the embodiment of the present invention does not change significantly with the increase of ambient temperature, while the slump loss of the existing commercial water-reducing agent changes greatly with the increase of ambient temperature. The slump change range of the water-reducing agent prepared by the embodiment of the present invention is less than 3.1%, and the expansion change range is less than 7.2%, indicating that the water-reducing agent prepared by the present invention is less sensitive to ambient temperature.

[0121] In summary, the low-sensitivity, high-slump-retention polycarboxylate water-reducing agent provided by the present invention has good slump retention ability and low sensitivity of the prepared concrete under different ambient temperatures, cement types, and machine-made sand dosage conditions, and has excellent water retention and mechanical properties, high water reduction effect, and excellent adaptability and stability. In addition, the preparation method of the water-reducing agent provided by the present invention is simple and easy, has strong operability, is environmentally friendly, and the reaction process is easy to control, which has significant advantages in modern concrete construction applications.

[0122] The technical features of the above-described embodiments may be arbitrarily combined. To make the description concise, not all possible combinations of the technical features in the above-described embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0123] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modification, equivalent substitution or improvement made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims

1. A low-sensitivity, high-slump-reducing polycarboxylate water-reducing agent, characterized in that: The invention comprises the following components in parts by weight: 150 to 200 parts of polyether macromonomer, 5 to 10 parts of unsaturated ester monomer, 20 to 30 parts of unsaturated carboxylic acid monomer, 5 to 8 parts of benzenesulfonic acid butylene dicarboxylic acid monoester functional monomer, 8 to 10 parts of amide functional monomer, 1 to 3 parts of ferrous sulfate-hydrogen peroxide mixture, 0.5 to 1.5 parts of reducing agent, 0.4 to 0.9 parts of chain transfer agent, 3 to 6 parts of pH regulator, and diluted with water to 250 to 300 parts; The preparation method of the benzenesulfonic acid butylene dicarboxylic acid monoester functional monomer comprises: 4-Hydroxybenzenesulfonic acid and maleic anhydride are added to a solvent cyclohexane, and a superacid catalyst is added at the same time, mixed evenly, heated and stirred, and an esterification reaction is carried out at 70° C. to 80° C. under reflux. After the reaction is complete, the temperature is increased to evaporate and remove the solvent, and the product is naturally cooled to room temperature, and the product is washed and dried to obtain the benzenesulfonic acid maleic acid monoester functional monomer.

2. The low-sensitivity, high-slump-reducing polycarboxylate water-reducing agent according to claim 1, characterized in that: The polyether macromonomer is at least one of 3-allylphenol polyoxyethylene polyoxypropylene ether, ethylene glycol monovinyl polyethylene glycol ether and ethoxy vinyl polyethylene glycol ether; and / or The preparation of the 3-allylphenol polyoxyethylene polyoxypropylene ether comprises: adding sodium ethoxide as a catalyst to 3-allylphenol, and then adding ethylene oxide and propylene oxide to the mixed solution respectively under nitrogen protection, controlling the reaction temperature at 120°C to 140°C, performing the polymerization reaction for 2h to 3.5h, and cooling the temperature to room temperature after the reaction is completed, thereby obtaining the 3-allylphenol polyoxyethylene polyoxypropylene ether.

3. The low-sensitivity, high-slump-reducing polycarboxylate water-reducing agent according to claim 1, characterized in that: The unsaturated ester monomer is a mixture of at least two of trimethylolpropane triacrylate, ethoxylated trimethylolpropane triacrylate, allyl hexanoate, allyl heptanoate, allyl phenoxyacetate, furfuryl methacrylate and polyethylene glycol methacrylate in equal weight.

4. The low-sensitivity, high-slump-reducing polycarboxylate water-reducing agent according to claim 1, characterized in that: The unsaturated carboxylic acid monomer is a mixture of at least two of itaconic acid, 2-methyl-2-butenoic acid, 3-methylbutenoic acid, 2-methyl-2-pentenoic acid and fumaric acid in equal weight.

5. The low-sensitivity, high-slump-reducing polycarboxylate water-reducing agent according to claim 1, characterized in that: The amide functional monomer is at least one of N,N-diallylacrylamide, N-allylformamide, N-allylacrylamide, N-hydroxymethylacrylamide and 2-acrylamide-2-methylpropanesulfonic acid.

6. The low-sensitivity, high-slump-reducing polycarboxylate water-reducing agent according to claim 1, characterized in that: The chain transfer agent is at least one of thioglycolic acid, thioglycolic acid and 3-mercaptopropionic acid; and / or The reducing agent is at least one of Bruggolite FF6, sodium sulfite and sodium hypophosphite; and / or The mass ratio of ferrous sulfate to hydrogen peroxide in the ferrous sulfate-hydrogen peroxide mixture is (0.1-0.2):1; and / or The pH regulator is industrial liquid alkali with a mass fraction of 25% to 40%.

7. The low-sensitivity, high-slump-reducing polycarboxylate water-reducing agent according to claim 1, characterized in that: In the preparation method of the benzenesulfonic acid maleic acid monoester functional monomer, the mass parts of the raw materials are respectively: 100-150 parts of 4-hydroxybenzenesulfonic acid, 20-50 parts of maleic anhydride, 50-100 parts of cyclohexane, and 4-7 parts of superacid catalyst.

8. The low-sensitivity, high-slump-reducing polycarboxylate water-reducing agent according to claim 1, characterized in that: The super acid catalyst is HND-31 solid super acid catalyst; and / or The stirring speed is 400r / min to 500r / min; and / or The esterification reaction time is 3.5h to 5h; and / or The temperature during the heating and evaporation to remove the solvent is 85°C to 90°C; and / or The washing is washing with water for 3 to 5 times; and / or The drying is vacuum drying for 5 h to 6 h.

9. The method for preparing the low-sensitivity high-slump-reducing polycarboxylate water-reducing agent according to any one of claims 1 to 8, characterized in that: The following steps are involved: Step a: adding 5 to 10 parts of unsaturated ester monomers, 5 to 7 parts of unsaturated carboxylic acid monomers and 1 to 3 parts of ferrous sulfate-hydrogen peroxide mixture into 10 to 20 parts of water, mixing and stirring, and then adding 5 to 8 parts of benzenesulfonic acid butenedioic acid monoester functional monomers and 8 to 10 parts of amide functional monomers into the mixed solution to obtain a functional monomer mixed solution; Step b: adding 150 to 200 parts of polyether macromonomer to 30 to 50 parts of water, heating to 30° C. to 40° C., stirring and mixing to obtain a macromonomer aqueous solution; Step c: Add 0.5-1.5 parts of a reducing agent and 0.4-0.9 parts of a chain transfer agent to the aqueous solution of the macromonomer obtained in step b, mix well, and then drip the functional monomer mixture obtained in step a, the dripping speed of the functional monomer mixture is 0.08mL / min-0.10mL / min, and after the dripping of the functional monomer mixture is completed, continue to drip the remaining unsaturated carboxylic acid monomer, the dripping speed of the unsaturated carboxylic acid monomer is 0.1mL / min-0.15mL / min, and control the reaction temperature to be 30°C-40°C. After the dripping of the unsaturated carboxylic acid monomer is completed, continue to stir, react for a period of time, add 3-6 parts of a pH adjuster, and after the reactants are aged and naturally cooled, dilute with water to 250-300 parts, mix well, and obtain the low-sensitivity, high-retention, collapse-reducing polycarboxylic acid water-reducing agent.

10. The preparation method according to claim 9, characterized in that: In step a, the stirring speed is 50 r / min to 60 r / min, and the stirring time is 5 min to 10 min; and / or In step b, the stirring speed is 400r / min to 500r / min; and / or In step c, after the unsaturated carboxylic acid monomer is added dropwise, the stirring speed is 300 r / min to 400 r / min, the reaction time is 2 h to 3 h, and the pH adjuster is added to adjust the pH to 6.0 to 7.0.

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