CN114671982A - A kind of shrinkage-reducing polycarboxylate water-reducing agent and preparation method thereof - Google Patents

Abstract

The invention discloses a shrinkage-reducing polycarboxylic acid water reducing agent and a preparation method thereof, and belongs to the technical field of concrete admixtures. The shrinkage-reducing polycarboxylic acid water reducer comprises shrinkage-reducing functional polymeric monomers, unsaturated carboxylic acid alkyl ester, sulfonic acid group monomers, polyether macromonomers, dispersant water, an initiator, a molecular weight regulator and distilled water, wherein after the raw materials are reacted completely under certain conditions, the raw materials are cooled to 20-30 ℃, and then alkali liquor is added to regulate the pH value, so that the polycarboxylic acid water reducer with the shrinkage-reducing function is obtained. According to the polycarboxylate superplasticizer with the shrinkage reducing function, due to the fact that the shrinkage reducing group is grafted on the molecular structure chain of the polycarboxylate superplasticizer, the polycarboxylate superplasticizer has the functions of reducing water, keeping strength and preventing slump, has a good shrinkage reducing effect, can compensate shrinkage to a certain extent, delays the time for generating cracks of concrete and the development width of the cracks, and introduces a new way for inhibiting self-shrinkage and shrinkage cracking of the concrete.

Description

A kind of shrinkage-reducing polycarboxylate water-reducing agent and preparation method thereof

technical field

The invention belongs to the technical field of concrete admixtures, in particular to a shrinkage-reducing polycarboxylate water-reducing agent and a preparation method thereof.

Background technique

In recent years, with the rapid progress of the construction industry and the gradual improvement of the design level, modern concrete is also developing in the direction of high strength and high performance. However, due to various reasons of the internal structure during the hardening and forming process of concrete, the excessive shrinkage of concrete during the hardening process has always been an important factor affecting the quality of concrete projects. Concrete often undergoes two shrinkage deformations. One is the drying shrinkage of concrete. This phenomenon is the shrinkage of hardened concrete caused by the evaporation of water in the capillary pores, which is the result of the volatilization of water inside the concrete to the outside. The second is the self-shrinking of concrete. This phenomenon is the shrinkage caused by self-drying or the reduction of relative humidity inside the concrete, and it is the phenomenon that the macroscopic volume of concrete is reduced due to the hydration of cement under constant temperature conditions. These two kinds of shrinkage deformation are the key factors that lead to the occurrence of non-load cracks in concrete structures. Cracks in concrete will lead to structural leakage, corrosion of steel bars, and reduction of strength, thereby reducing the durability of concrete, causing damage and collapse of structures, thus seriously affecting Safety performance and service life of concrete.

Shrinkage cracks in concrete not only affect the aesthetics of the structure, but also endanger the integrity, watertightness and durability of the building. Especially the application of pumped concrete, high-strength concrete, high-performance concrete, superplasticizer and superfine admixture makes the problem of concrete cracks more and more serious. How to reduce the shrinkage of concrete has always been a topic worthy of research in the field of concrete. Engineering practice shows that a polycarboxylate superplasticizer with shrinkage-reducing function has a high water-reducing rate and strength retention due to grafted shrinkage-reducing groups on the side chain of the molecular structure of the polycarboxylate superplasticizer. At the same time, it has a good shrinkage reduction effect, which can compensate the shrinkage to a certain extent, delay the time of concrete crack generation and the width of crack development, and open up a new way to inhibit the self-shrinkage and drying shrinkage cracking of concrete. Therefore, it is of great practical significance to develop a polycarboxylate water-reducing agent with shrinkage-reducing function to improve the stability of the concrete material structure, reduce the generation of cracks, and then improve the durability of the concrete material structure.

Patent application publication CN102112412B reported a polyether polyol alkane compound containing polyoxyalkylene group, and the patent reported that this shrinkage-reducing water-reducing agent may indeed have a certain shrinkage-reducing effect when mixed into concrete, but the dosage is relatively high, The cost is also high, and the high content of the simple shrinkage reducer will affect the fluidity and strength of the concrete.

Patent application publication CN104262545A reports a low-entrainment condensation-reducing polycarboxylate water reducer and its preparation method. The patent is to polymerize the raw materials into a polycarboxylate water reducer by free radicals. A slight improvement on the basis of the traditional polycarboxylate water reducing agent may have a certain shrinkage reduction effect. However, the final product has poor compatibility with cement and other functional water reducers and cannot be uniformly distributed in the concrete system.

Patent CN108164653A reports a shrinkage-reducing polycarboxylate water-reducing agent and its preparation method. When synthesizing the polycarboxylate water-reducing agent in the later stage, the free radical copolymerization does not avoid the oxidation of oxygen in this process. In principle, nitrogen protection is more effective. Reasonable, otherwise the oxidation process will lead to the increase of by-products and the complexity of the system components, so that the actual shrinkage and water-reduction effects of each batch of products cannot be consistent, so the process conditions need to be further optimized.

SUMMARY OF THE INVENTION

The present invention aims to solve the above-mentioned technical problems, and provides a condensation-reducing polycarboxylate water-reducing agent and a preparation method thereof.

In order to achieve the above object, the present invention adopts the following technical solutions:

A shrinkage-reducing polycarboxylate water-reducing agent, comprising the effective components of the following structure:

；

;

Among them, a, b, c, d, x, y and z are all integers, and a=1～30, b=10～65, c=1～25, d=1～18, x=1～32, And x represents the average added moles of oxyalkylene groups (—R7—O—), y=1～20, and y represents the average added moles of oxyalkylene groups (—R8—O—), z= 5～27;

R1 and R2 are -H or -CH3, R3 is an alkyl group of 1-2 carbons, R4 is -H or an alkyl group of 1-2 carbons, R5 is -H or -CH3, R6 is 1-2 carbons R7 is C2～C20 alkylene, R8 is C2～C4 alkylene, R9 is -H or 2～3 carbon alkyl, A is C1～C3 alkylene, M is C1～C3 alkylene Na or K or NH4.

A preparation method of a shrinkage-reducing polycarboxylate water-reducing agent, comprising the following steps:

Step (1), preparation of shrinkage-reducing functional polymerizable monomers:

Add distilled water, molar salt and maleic anhydride into the reactor, and heat to 60℃～80℃;

70-74% acrylic acid aqueous solution, 73-77% propylene oxide aqueous solution, 53-57% isoprenol aqueous solution, 13-17% sodium persulfate, 13-17% sulfurous acid are added dropwise to the reactor Sodium hydrogen participates in the reaction as an initiator;

After the dropwise addition is completed, the obtained solution is further aged for 40 to 70 minutes at the same controlled temperature, and after the reaction is completed, it is allowed to stand for cooling to obtain an alkylene glycol/alkenyl ether/maleic anhydride shrinkage-reducing functional copolymer, which is The structural units are as follows:

；

;

Step (2), the preparation of shrinkage-reducing polycarboxylate water-reducing agent:

Add the shrinkage-reducing functional polymerized monomer obtained in step (1) and distilled water into the reactor, heat up to 35°C to 45°C, and stir for 10 to 30 minutes;

After the shrinkage-reducing functional polymer monomer and distilled water are evenly mixed, add unsaturated carboxylic acid alkyl ester and sulfonic acid group monomer, and under nitrogen protection, heat and stir in a constant temperature water bath;

When the reaction temperature reaches 60 ℃ ~ 75 ℃, start to slowly add polyether macromonomer and dispersant aqueous solution, and at the same time slowly add initiator and molecular weight regulator, the adding duration of the above four raw materials is controlled at 90 ~ 120 minutes, after the dropwise addition is completed, the constant temperature reaction is performed for 4 to 6 hours;

After the reaction is completed, it is cooled to 20°C to 30°C, and then 30 to 35% sodium hydroxide solution is added to adjust pH=6 to 8 to obtain a condensation-reducing polycarboxylate water-reducing agent.

Preferably, in step (1), the weight ratio of the molar salt, maleic anhydride and sodium bisulfite is: 1:5-10:8-18; the sodium bisulfite, sodium persulfate, acrylic acid The weight ratio of the aqueous solution, the aqueous propylene oxide solution, the aqueous solution of isoprenol and the distilled water is 1:2-3:5.5-8.5:3.5-6:2.5-4.5:5.5-7.5.

Preferably, in step (2), the unsaturated carboxylic acid alkyl ester includes one or more of dimethylaminoethyl acrylate, dimethylaminoethyl methacrylate, dimethylaminopropyl acrylate, etc. Mixed substances in any proportion; the sulfonic acid-based monomers include vinyl sulfonic acid, methallyl sulfonic acid, isoprene sulfonic acid, 3-allyloxy-2-hydroxypropane sulfonic acid, propylene One or more of the amide-2-methylpropanesulfonic acid and the salts of these acids are mixed in any proportion.

Preferably, in step (2), the polyether macromonomer includes methoxy polyethylene glycol ether, prenol polyethylene glycol ether, allyl alcohol polyethylene glycol ether and isobutenol polyethylene glycol One or more of the ethers are mixed in any proportion; the dispersant is an alkylamide betaine.

Preferably, in step (2), the initiator includes one or more of hydrogen peroxide, ammonium persulfate, benzoyl peroxide, and dimethyl azobisisobutyrate mixed in any proportion. substance; the molecular weight regulator includes one or more substances mixed in any proportion among mercaptoethanol, mercaptoacetic acid, mercaptopropionic acid, isopropanol and dodecyl mercaptan.

Preferably, the dispersing agent includes one or more of lauramidopropyl betaine, cocamidopropyl betaine, and octadecamidopropyl betaine, mixed and mixed in any proportion.

Preferably, the weight ratio of the sulfonic acid-based monomer, the shrinkage-reducing functional polymerized monomer, the unsaturated carboxylic acid alkyl ester, the polyether macromonomer, and the distilled water is: 1:3.5-4.5:1.5-2.5:5.5-10 : 12～18; preferably, the weight ratio of the sulfonic acid-based monomer, the shrinkage-reducing functional polymer monomer, the unsaturated carboxylic acid alkyl ester, the polyether macromonomer, and the distilled water is: 1:3.8～4.2:1.7～ 2.1:5.7～9.5:13.6～17.3.

Preferably, the dosage of the dispersant is 0.5% to 2% of the weight of the polyether macromonomer, the dosage of the initiator is 0.2% to 0.7% of the weight of the polyether macromonomer, and the dosage of the molecular weight regulator is the amount of the polyether macromonomer. 0.3% to 0.8% of the weight of the macromonomer; preferably, the amount of the dispersant is 0.6% to 1.3% of the weight of the polyether macromonomer, and the amount of the initiator is 0.25% to 0.41% of the weight of the polyether macromonomer %, the dosage of the molecular weight regulator is 0.34% to 0.52% of the weight of the polyether macromonomer.

Preferably, in step (1), 72% acrylic acid aqueous solution, 75% propylene oxide aqueous solution, 55% isoprenol aqueous solution, 15% sodium persulfate, 15% hydrogen sulfite are added dropwise to the reactor Sodium participates in the reaction as an initiator.

After adopting the above-mentioned technical scheme, the present invention has the following advantages:

(1) The shrinkage-reducing polycarboxylate water-reducing agent of the present invention is a concrete admixture with both "shrinkage-reducing" and "water-reducing" functions. Good compatibility and long-term application prospects;

(2) The molecular structure of the shrinkage-reducing polycarboxylate water-reducing agent of the present invention contains a large number of alcoholic hydroxyl groups, amides, amino groups and other hydrophilic groups, and cross-linking occurs during the polymerization process, increasing the space of the system Steric hindrance effect, this steric hindrance effect makes the water reducing agent of the present invention have better dispersing performance in concrete, can be evenly distributed in the concrete system, and is not adsorbed on the surface by cement particles, etc.;

(3) The shrinkage-reducing polycarboxylate water-reducing agent of the present invention contains a structural monomer of unsaturated carboxylic acid alkyl ester, which releases carboxylate with water-reducing function in the alkaline environment of concrete. acid group, so that the water reducing agent finally obtained by the present invention has outstanding slump retention effect;

(4) There is an alkylene glycol/alkenyl ether/maleic anhydride structural unit in the shrinkage-reducing polycarboxylate water-reducing agent of the present invention, and this structural unit, as a surface active active ingredient, contributes due The shrinkage reduction function, because it can reduce the surface tension of the liquid phase in the concrete capillary, reduce the negative pressure in the capillary, reduce the shrinkage stress, and effectively reduce the shrinkage rate of the concrete;

(5) The shrinkage-reducing and water-reducing effects of the shrinkage-reducing polycarboxylate water-reducing agent of the present invention are less affected by temperature. After being added to concrete, it can reduce the heat of hydration of cement, but does not hinder the normal water content of cement. It can maintain the good plasticity of the cement paste within a certain period of time;

(6) The shrinkage-reducing polycarboxylate water-reducing agent of the present invention can meet the requirements of environmental protection, has low volatility and no abnormal causing effect, can ensure the required strength of concrete, and is not easily affected by acids and alkalis. As an admixture, the dosage in concrete is low, the raw materials are readily available, and the synthesis process is clear.

Detailed ways

A shrinkage-reducing polycarboxylate water-reducing agent, comprising the effective components of the following structure:

；

;

Among them, a, b, c, d, x, y and z are all integers, and a=1～30, b=10～65, c=1～25, d=1～18, x=1～32, And x represents the average added moles of oxyalkylene groups (—R7—O—), y=1～20, and y represents the average added moles of oxyalkylene groups (—R8—O—), z= 5～27;

R1 and R2 are -H or -CH3, R3 is an alkyl group of 1-2 carbons, R4 is -H or an alkyl group of 1-2 carbons, R5 is -H or -CH3, R6 is 1-2 carbons R7 is C2～C20 alkylene, R8 is C2～C4 alkylene, R9 is -H or 2～3 carbon alkyl, A is C1～C3 alkylene, M is C1～C3 alkylene Na or K or NH4.

The preparation method of the above-mentioned shrinkage-reducing polycarboxylate water-reducing agent will be further described in detail below with reference to specific examples.

Example 1

A shrinkage-reducing polycarboxylate water-reducing agent and a preparation method thereof are realized by the following steps:

(1) Preparation of polymerized monomer with shrinkage-reducing function: In a detachable temperature-controlled reactor equipped with a reflux condenser, agitator and a four-necked flask, add distilled water, molar salt and maleic anhydride, and heat to 70°C at the same time , 72% acrylic acid aqueous solution, 75% propylene oxide aqueous solution, 55% isoprenol aqueous solution were added dropwise through different openings in the mixture, and 15% sodium persulfate and 15% sodium bisulfite were added as The initiator participates in the reaction. The dropwise addition times of acrylic acid, propylene oxide, sodium persulfate and sodium bisulfite were respectively 75 minutes, 80 minutes, 70 minutes and 70 minutes. Take the mode of dropping the above-mentioned various solutions at the same time, after the dropping is completed, the obtained solution is further matured for 40 minutes at the same controlled temperature, and after the reaction is completed, it is allowed to stand for cooling, and the alkylene glycol/alkene is obtained through the above steps. base ether/maleic anhydride shrinkage-reducing functional copolymer, wherein the weight ratio of molar salt, maleic anhydride and sodium bisulfite is: 1:5:11; the sodium bisulfite, sodium persulfate, acrylic acid aqueous solution, cyclic The weight ratio of the oxypropane aqueous solution, the isoprenol aqueous solution and the distilled water is 1:2:6:3.5:4:5.5.

(2) Preparation of shrinkage-reducing polycarboxylate water-reducing agent: In a detachable temperature-controlled reactor equipped with a reflux condenser, agitator and a four-necked bottle, add the shrinkage-reducing functional polymer monomer and distilled water into the four-necked bottle. , heat up to 42 ℃, stir for 25 minutes, add dimethylaminoethyl acrylate and isoprene sulfonic acid after mixing evenly, under nitrogen protection, heat and stir in a constant temperature water bath, and start slowly when the reaction temperature reaches 65 ℃ Add the prenyl alcohol polyglycol ether and the lauryl amidopropyl betaine aqueous solution that the molecular weight is 3000, slowly drip ammonium persulfate and mercaptopropionic acid at the same time, the adding duration of the above-mentioned four kinds of raw materials is controlled at 112 minutes , after the dropwise addition is completed, the constant temperature reaction is performed for 5h, wherein the weight ratio of the isoprene sulfonic acid, the shrinkage-reducing functional polymerization monomer, dimethylaminoethyl acrylate, the prenol polyglycol ether, and the distilled water is: 1:4:2.1:9.5:16.4, the amount of lauramidopropyl betaine is 1.1% of the weight of prenol polyethylene glycol ether, and the amount of ammonium persulfate is prenol polyethylene glycol 0.28% of the weight of the ether, and the amount of the mercaptopropionic acid used is 0.46% of the weight of the prenol polyethylene glycol ether. After the reaction is completed, it is cooled to 25° C., and then 32% sodium hydroxide solution is added to adjust pH=7.2 to obtain a shrinkage-reducing polycarboxylate water-reducing agent.

Example 2

A shrinkage-reducing polycarboxylate water-reducing agent and a preparation method thereof are realized by the following steps:

(1) Preparation of polymerized monomer with shrinkage-reducing function: In a detachable temperature-controlled reactor equipped with a reflux condenser, agitator and a four-necked flask, add distilled water, molar salt and maleic anhydride, and heat to 75°C at the same time , 72% acrylic acid aqueous solution, 75% propylene oxide aqueous solution, 55% isoprenol aqueous solution were added dropwise through different openings in the mixture, and 15% sodium persulfate and 15% sodium bisulfite were added as The initiator participates in the reaction. The dropwise addition times of acrylic acid, propylene oxide, sodium persulfate and sodium bisulfite were respectively 70 minutes, 75 minutes, 70 minutes and 75 minutes. Adopt the mode of dropping the above-mentioned various solutions at the same time, after the dropping is completed, the obtained solution is further matured for 42 minutes at the same controlled temperature, and after the reaction is completed, it is allowed to stand for cooling, and the alkylene glycol/alkene is obtained through the above steps. Base ether/maleic anhydride shrinkage-reducing functional copolymer, wherein the weight ratio of molar salt, maleic anhydride, and sodium bisulfite is: 1:8:10; The weight ratio of the oxypropane aqueous solution, the isoprenol aqueous solution and the distilled water is 1:2.4:6.8:5.1:3.8:7.5.

(2) Preparation of shrinkage-reducing polycarboxylate water-reducing agent: In a detachable temperature-controlled reactor equipped with a reflux condenser, agitator and a four-necked bottle, add the shrinkage-reducing functional polymer monomer and distilled water into the four-necked bottle. , heat up to 40 ℃, stir for 27 minutes, add dimethylaminoethyl acrylate and vinyl sulfonic acid after mixing evenly, under nitrogen protection, heat and stir in a constant temperature water bath, when the reaction temperature reaches 70 ℃, slowly add molecular weight Be 2000 of isoprenol polyglycol ether and lauryl amidopropyl betaine aqueous solution, slowly drip ammonium persulfate and mercaptopropionic acid at the same time, the adding duration of above-mentioned four kinds of raw materials is controlled at 105 minutes, wait for After the dropwise addition, the constant temperature reaction was carried out for 5.5h, wherein the weight ratio of vinyl sulfonic acid, shrinkage-reducing functional polymer monomer, dimethylaminoethyl acrylate, prenol polyglycol ether, and distilled water was: 1:3.5 : 1.5:6.2:18, the described lauryl amidopropyl betaine consumption is 2% of the prenol polyglycol ether weight, and the described ammonium persulfate consumption is the prenol polyglycol ether weight of 2%. 0.7%, the mercaptopropionic acid consumption is 0.69% by weight of the prenol polyglycol ether. After the reaction is completed, it is cooled to 26° C., and then 32% sodium hydroxide solution is added to adjust pH=6.8 to obtain a shrinkage-reducing polycarboxylate water-reducing agent.

Example 3

A shrinkage-reducing polycarboxylate water-reducing agent and a preparation method thereof are realized by the following steps:

(1) Preparation of polymerized monomer with shrinkage-reducing function: In a detachable temperature-controlled reactor equipped with a reflux condenser, agitator and a four-necked flask, add distilled water, Mohr salt and maleic anhydride, and heat to 80°C at the same time , 72% acrylic acid aqueous solution, 75% propylene oxide aqueous solution, 55% isoprenol aqueous solution were added dropwise through different openings in the mixture, and 15% sodium persulfate and 15% sodium bisulfite were added as The initiator participates in the reaction. The dropwise addition times of acrylic acid, propylene oxide, sodium persulfate and sodium bisulfite were respectively 70 minutes, 75 minutes, 70 minutes and 75 minutes. Adopt the mode of dropping the above-mentioned various solutions at the same time, after the dropping is completed, the obtained solution is further matured for 42 minutes at the same controlled temperature, and after the reaction is completed, it is allowed to stand for cooling, and the alkylene glycol/alkene is obtained through the above steps. Base ether/maleic anhydride shrinkage-reducing functional copolymer, wherein the weight ratio of molar salt, maleic anhydride, and sodium bisulfite is: 1:8:10; The weight ratio of the oxypropane aqueous solution, the isoprenol aqueous solution and the distilled water is 1:2.4:6.8:5.5:3.8:7.5.

(2) Preparation of shrinkage-reducing polycarboxylate water-reducing agent: In a detachable temperature-controlled reactor equipped with a reflux condenser, agitator and a four-necked bottle, add the shrinkage-reducing functional polymer monomer and distilled water into the four-necked bottle. , heat up to 40°C, stir for 30 minutes, add dimethylaminoethyl methacrylate and methallyl sulfonic acid after mixing evenly, under nitrogen protection, heat and stir in a constant temperature water bath, when the reaction temperature reaches 75°C Begin to slowly add isoprenol polyglycol ether and lauryl amidopropyl betaine aqueous solution that molecular weight is 2000, slowly drip ammonium persulfate, mercaptopropionic acid simultaneously, the adding duration control of above-mentioned four kinds of raw materials At 105 minutes, after the dropwise addition is completed, a constant temperature reaction is performed for 5.5 hours, wherein the methallyl sulfonic acid, the shrinkage-reducing functional polymer monomer, dimethylaminoethyl methacrylate, and the prenol polyglycol ether , the weight ratio of distilled water is: 1:4.2:2.1:6.2:17.3, the described lauryl amidopropyl betaine consumption is 0.5% of the prenol polyglycol ether weight, and the described ammonium persulfate consumption is different. 0.2% of the weight of the pentenol polyethylene glycol ether, and the amount of the mercaptopropionic acid is 0.35% of the weight of the prenol polyethylene glycol ether. After the reaction is completed, it is cooled to 26° C., and then 32% sodium hydroxide solution is added to adjust pH=6 to obtain a shrinkage-reducing polycarboxylate water-reducing agent.

Example 4

A shrinkage-reducing polycarboxylate water-reducing agent and a preparation method thereof are realized by the following steps:

(1) Preparation of polymerized monomer with shrinkage-reducing function: In a detachable temperature-controlled reactor equipped with a reflux condenser, agitator and a four-necked flask, add distilled water, molar salt and maleic anhydride, and heat to 75°C at the same time , 72% acrylic acid aqueous solution, 75% propylene oxide aqueous solution, 55% isoprenol aqueous solution were added dropwise through different openings in the mixture, and 15% sodium persulfate and 15% sodium bisulfite were added as The initiator participates in the reaction. The dropwise addition times of acrylic acid, propylene oxide, sodium persulfate, and sodium bisulfite were 77 minutes, 73 minutes, 73 minutes, and 77 minutes, respectively. Take the method of dropping the above-mentioned various solutions at the same time. After the dropping is completed, the obtained solution is further matured for 45 minutes at the same controlled temperature. Base ether/maleic anhydride shrinkage-reducing functional copolymer, wherein the weight ratio of molar salt, maleic anhydride, and sodium bisulfite is: 1:7.6:15; The weight ratio of the oxypropane aqueous solution, the isoprenol aqueous solution and the distilled water is 1:2.8:7.8:5.1:3.6:7.5.

(2) Preparation of shrinkage-reducing polycarboxylate water-reducing agent: In a detachable temperature-controlled reactor equipped with a reflux condenser, agitator and a four-necked bottle, add the shrinkage-reducing functional polymer monomer and distilled water into the four-necked bottle. , heat up to 45°C, stir for 30 minutes, add dimethylaminoethyl acrylate and vinylsulfonic acid after mixing evenly, under nitrogen protection, heat and stir in a constant temperature water bath, when the reaction temperature reaches 70°C, slowly add molecular weight Be 2000 of isoprenol polyglycol ether and lauryl amidopropyl betaine aqueous solution, slowly drip ammonium persulfate and mercaptopropionic acid at the same time, the adding duration of above-mentioned four kinds of raw materials is controlled at 105 minutes, wait for After the dropwise addition, the constant temperature reaction was carried out for 5.5 hours, wherein the weight ratio of vinyl sulfonic acid, shrinkage-reducing functional polymerization monomer, dimethylaminoethyl acrylate, prenol polyglycol ether, and distilled water was: 1:3.9 : 1.9:5.5:12, the described lauryl amidopropyl betaine consumption is 1.3% of the weight of prenol polyglycol ether, and the described ammonium persulfate consumption is 1.3% of the weight of prenol polyglycol ether. 0.35%, the mercaptopropionic acid consumption is 0.41% by weight of the prenol polyglycol ether. After the reaction is completed, it is cooled to 26° C., and then 32% sodium hydroxide solution is added to adjust pH=6.5 to obtain a shrinkage-reducing polycarboxylate water-reducing agent.

Example 5

A shrinkage-reducing polycarboxylate water-reducing agent and a preparation method thereof are realized by the following steps:

(1) Preparation of polymerized monomer with shrinkage-reducing function: In a detachable temperature-controlled reactor equipped with a reflux condenser, agitator and a four-necked flask, add distilled water, molar salt and maleic anhydride, and heat to 75°C at the same time , 72% acrylic acid aqueous solution, 75% propylene oxide aqueous solution, 55% isoprenol aqueous solution were added dropwise through different openings in the mixture, and 15% sodium persulfate and 15% sodium bisulfite were added as The initiator participates in the reaction. The dropwise addition times of acrylic acid, propylene oxide, sodium persulfate and sodium bisulfite were respectively 75 minutes, 73 minutes, 76 minutes and 74 minutes. Take the mode of dropping the above-mentioned various solutions at the same time, after the dropping is completed, the obtained solution is further matured for 40 minutes at the same controlled temperature, and after the reaction is completed, it is allowed to stand for cooling, and the alkylene glycol/alkene is obtained through the above steps. Base ether/maleic anhydride shrinkage-reducing functional copolymer, wherein the weight ratio of molar salt, maleic anhydride and sodium bisulfite is: 1:8.8:18; the sodium bisulfite, sodium persulfate, acrylic acid aqueous solution, cyclic The weight ratio of the oxypropane aqueous solution, the isoprenol aqueous solution and the distilled water is 1:3:8.2:5.5:3.8:7.1.

(2) Preparation of shrinkage-reducing polycarboxylate water-reducing agent: In a detachable temperature-controlled reactor equipped with a reflux condenser, agitator and a four-necked bottle, add the shrinkage-reducing functional polymer monomer and distilled water into the four-necked bottle. , heat up to 42 °C, stir for 30 minutes, add dimethylaminoethyl acrylate and methallyl sulfonic acid after mixing evenly, under nitrogen protection, heat and stir in a constant temperature water bath, start when the reaction temperature reaches 70 °C Slowly adding molecular weight is 4000 propenyl alcohol polyglycol ether and cocamidopropyl betaine aqueous solution, slowly dripping ammonium persulfate, mercaptopropionic acid simultaneously, the adding duration of above-mentioned four kinds of raw materials is controlled at 105 minutes, After the dropwise addition is completed, the constant temperature reaction is carried out for 5.5h, wherein the weight ratio of the methallyl sulfonic acid, the shrinkage-reducing functional polymer monomer, the dimethylaminoethyl acrylate, the propylene alcohol polyethylene glycol ether, and the distilled water is: 1 : 3.9: 1.9: 6.2: 17.3, the cocamidopropyl betaine consumption is 1.3% of the propenyl alcohol polyglycol ether weight, and the described ammonium persulfate consumption is 0.35% of the propenyl alcohol polyglycol ether weight , the amount of mercaptopropionic acid is 0.8% of the weight of propylene alcohol polyethylene glycol ether. After the reaction is completed, it is cooled to 26° C., and then 32% sodium hydroxide solution is added to adjust pH=6.8 to obtain a shrinkage-reducing polycarboxylate water-reducing agent.

Example 6

A shrinkage-reducing polycarboxylate water-reducing agent and a preparation method thereof are realized by the following steps:

(1) Preparation of polymerized monomer with shrinkage-reducing function: In a detachable temperature-controlled reactor equipped with a reflux condenser, agitator and a four-necked flask, add distilled water, molar salt and maleic anhydride, and heat to 70°C at the same time , 72% acrylic acid aqueous solution, 75% propylene oxide aqueous solution, 55% isoprenol aqueous solution were added dropwise through different openings in the mixture, and 15% sodium persulfate and 15% sodium bisulfite were added as The initiator participates in the reaction. The dropwise addition times of acrylic acid, propylene oxide, sodium persulfate and sodium bisulfite were respectively 75 minutes, 80 minutes, 70 minutes and 70 minutes. Take the mode of dropping the above-mentioned various solutions at the same time, after the dropping is completed, the obtained solution is further matured for 40 minutes at the same controlled temperature, and after the reaction is completed, it is allowed to stand for cooling, and the alkylene glycol/alkene is obtained through the above steps. Base ether/maleic anhydride shrinkage-reducing functional copolymer, wherein the weight ratio of molar salt, maleic anhydride, and sodium bisulfite is: 1:10:17.3; The weight ratio of the oxypropane aqueous solution, the isoprenol aqueous solution and the distilled water is: 1:3:8.5:5:4:6.8.

(2) Preparation of shrinkage-reducing polycarboxylate water-reducing agent: In a detachable temperature-controlled reactor equipped with a reflux condenser, agitator and a four-necked bottle, add the shrinkage-reducing functional polymer monomer and distilled water into the four-necked bottle. , heat up to 42°C, stir for 25 minutes, add dimethylaminoethyl acrylate and sodium methallyl sulfonate after mixing evenly, under nitrogen protection, heat and stir in a constant temperature water bath, when the reaction temperature reaches 65°C Begin to slowly add the isoprenol polyglycol ether and cocamidopropyl betaine aqueous solution that molecular weight is 3000, slowly drip hydrogen peroxide, mercaptopropionic acid simultaneously, the adding duration of above-mentioned four kinds of raw materials is controlled at 120 minutes, after the dropwise addition is completed, a constant temperature reaction is performed for 6 hours, wherein the sodium methallyl sulfonate, the shrinkage-reducing functional polymer monomer, dimethylaminoethyl acrylate, the prenol polyglycol ether, and distilled water are mixed. The weight ratio is: 1:4:2:8.2:16.8, the cocamidopropyl betaine consumption is 1.3% of the prenol polyglycol ether weight, and the hydrogen peroxide consumption is prenol 0.4% of the weight of the polyethylene glycol ether, and the amount of the mercaptopropionic acid is 0.52% of the weight of the prenol polyethylene glycol ether. After the reaction is completed, it is cooled to 20° C., and then 32% sodium hydroxide solution is added to adjust pH=7.5 to obtain a shrinkage-reducing polycarboxylate water-reducing agent.

Example 7

A shrinkage-reducing polycarboxylate water-reducing agent and a preparation method thereof are realized by the following steps:

(1) Preparation of polymerized monomer with shrinkage-reducing function: In a detachable temperature-controlled reactor equipped with a reflux condenser, agitator and a four-necked flask, add distilled water, Mohr salt and maleic anhydride, and heat to 80°C at the same time , 72% acrylic acid aqueous solution, 75% propylene oxide aqueous solution, 55% isoprenol aqueous solution were added dropwise through different openings in the mixture, and 15% sodium persulfate and 15% sodium bisulfite were added as The initiator participates in the reaction. The dropwise addition times of acrylic acid, propylene oxide, sodium persulfate and sodium bisulfite were respectively 72 minutes, 75 minutes, 75 minutes and 77 minutes. Adopt the mode of dropping the above-mentioned various solutions at the same time, after the dropping is completed, the obtained solution is further matured for 42 minutes at the same controlled temperature, and after the reaction is completed, it is allowed to stand for cooling, and the alkylene glycol/alkene is obtained through the above steps. Base ether/maleic anhydride shrinkage-reducing functional copolymer, wherein the weight ratio of molar salt, maleic anhydride, and sodium bisulfite is: 1:7.1:14.9; The weight ratio of the oxypropane aqueous solution, the isoprenol aqueous solution and the distilled water is 1:2.4:6.9:5.5:4.5:6.3.

(2) Preparation of shrinkage-reducing polycarboxylate water-reducing agent: In a detachable temperature-controlled reactor equipped with a reflux condenser, agitator and a four-necked bottle, add the shrinkage-reducing functional polymer monomer and distilled water into the four-necked bottle. , heat up to 42°C, stir for 24 minutes, add dimethylaminoethyl acrylate and sodium methallyl sulfonate after mixing evenly, under nitrogen protection, heat and stir in a constant temperature water bath, when the reaction temperature reaches 75°C Begin to slowly add the isoprenol polyglycol ether and lauramidopropyl betaine aqueous solution that molecular weight is 4000, slowly drip ammonium persulfate, mercaptoacetic acid simultaneously, the adding duration of above-mentioned four kinds of raw materials is controlled at 112 minutes, after the dropwise addition is completed, a constant temperature reaction is performed for 5.5 hours, wherein the sodium methallyl sulfonate, the shrinkage-reducing functional polymer monomer, dimethylaminoethyl acrylate, the prenol polyglycol ether, and distilled water are mixed The weight ratio is: 1:4.1:1.9:8.2:15.9, the lauryl amidopropyl betaine consumption is 0.9% of the weight of prenol polyglycol ether, and the ammonium persulfate consumption is prenol 0.37% by weight of polyethylene glycol ether, and the amount of thioglycolic acid used is 0.5% by weight of prenol polyethylene glycol ether. After the reaction is completed, it is cooled to 30° C., and then 32% sodium hydroxide solution is added to adjust pH=7.3 to obtain a shrinkage-reducing polycarboxylate water-reducing agent.

Example 8

A shrinkage-reducing polycarboxylate water-reducing agent and a preparation method thereof are realized by the following steps:

(1) Preparation of polymerized monomers with shrinkage reduction function: In a detachable temperature-controlled reactor equipped with a reflux condenser, agitator and a four-necked flask, add distilled water, molar salt and maleic anhydride, and heat to 60°C at the same time , 72% acrylic acid aqueous solution, 75% propylene oxide aqueous solution, 55% isoprenol aqueous solution were added dropwise through different openings in the mixture, and 15% sodium persulfate and 15% sodium bisulfite were added as The initiator participates in the reaction. The dropwise addition times of acrylic acid, propylene oxide, sodium persulfate and sodium bisulfite were respectively 72 minutes, 75 minutes, 75 minutes and 77 minutes. Adopt the mode of dropping the above-mentioned various solutions at the same time, after the dropping is completed, the obtained solution is further matured for 70 minutes at the same controlled temperature, and after the reaction is completed, it is allowed to stand for cooling, and the alkylene glycol/alkene is obtained through the above steps. Base ether/maleic anhydride shrinkage-reducing functional copolymer, wherein the weight ratio of molar salt, maleic anhydride, and sodium bisulfite is: 1:5:8; The weight ratio of the oxypropane aqueous solution, the isoprenol aqueous solution and the distilled water is 1:2.4:5.5:6:2.5:6.3.

(2) Preparation of shrinkage-reducing polycarboxylate water-reducing agent: In a detachable temperature-controlled reactor equipped with a reflux condenser, agitator and a four-necked bottle, add the shrinkage-reducing functional polymer monomer and distilled water into the four-necked bottle. , heat up to 35 ℃, stir for 10 minutes, add dimethylaminoethyl acrylate and sodium methallyl sulfonate after mixing evenly, under nitrogen protection, heat and stir in a constant temperature water bath, when the reaction temperature reaches 60 ℃ Begin to slowly add the isoprenol polyglycol ether and lauramidopropyl betaine aqueous solution that molecular weight is 4000, slowly drip ammonium persulfate, mercaptoacetic acid simultaneously, the adding duration of above-mentioned four kinds of raw materials is controlled at 90 minutes, after the dropwise addition is completed, a constant temperature reaction is performed for 4 hours, wherein the weight of the sodium methallyl sulfonate, the shrinkage-reducing functional polymer monomer, dimethylaminoethyl acrylate, the prenol polyglycol ether, and distilled water The ratio is: 1:4.5:2.5:10:15.9, the consumption of the lauryl amidopropyl betaine is 0.9% of the weight of the prenol polyglycol ether, and the consumption of the ammonium persulfate is the prenol polyglycol ether. 0.42% of the weight of the glycol ether, and the amount of the thioglycolic acid used is 0.3% of the weight of the prenol polyglycol ether. After the reaction is completed, it is cooled to 28° C., and then 32% sodium hydroxide solution is added to adjust pH=8 to obtain a shrinkage-reducing polycarboxylate water-reducing agent.

Comparative Example 1

A shrinkage-reducing polycarboxylate water-reducing agent and a preparation method thereof are realized by the following steps:

(1) Preparation of polymerized monomer with shrinkage-reducing function: In a detachable temperature-controlled reactor equipped with a reflux condenser, agitator and a four-necked flask, add distilled water, molar salt and maleic anhydride, and heat to 70°C at the same time , 72% acrylic acid aqueous solution, 75% propylene oxide aqueous solution, 55% isoprenol aqueous solution were added dropwise through different openings in the mixture, and 15% sodium persulfate and 15% sodium bisulfite were added as The initiator participates in the reaction. The dropwise addition times of acrylic acid, propylene oxide, sodium persulfate and sodium bisulfite were respectively 75 minutes, 80 minutes, 70 minutes and 70 minutes. Take the mode of dropping the above-mentioned various solutions at the same time, after the dropping is completed, the obtained solution is further matured for 40 minutes at the same controlled temperature, and after the reaction is completed, it is allowed to stand for cooling, and the alkylene glycol/alkene is obtained through the above steps. base ether/maleic anhydride shrinkage-reducing functional copolymer, wherein the weight ratio of molar salt, maleic anhydride and sodium bisulfite is: 1:5:11; the sodium bisulfite, sodium persulfate, acrylic acid aqueous solution, cyclic The weight ratio of the oxypropane aqueous solution, the isoprenol aqueous solution and the distilled water is: 1:2:6:3.5:4:5.5.

(2) Preparation of shrinkage-reducing polycarboxylate water-reducing agent: In a detachable temperature-controlled reactor equipped with a reflux condenser, agitator and a four-necked bottle, add the shrinkage-reducing functional polymer monomer and distilled water into the four-necked bottle. , heat up to 42°C, stir for 25 minutes, add dimethylaminopropyl acrylate and acrylamide-2-methylpropanesulfonic acid after mixing evenly, under nitrogen protection, heat and stir in a constant temperature water bath, when the reaction temperature reaches 65 At ℃, start to slowly add isoprenol polyglycol ether and lauramidopropyl betaine aqueous solution with a molecular weight of 3000, and at the same time slowly add ammonium persulfate and mercaptopropionic acid dropwise, and the duration of the addition of the above four raw materials Controlled at 112 minutes, after the dropwise addition was completed, a constant temperature reaction was performed for 5 hours, wherein the acrylamide-2-methylpropanesulfonic acid, shrinkage-reducing functional polymer monomer, dimethylaminopropyl acrylate, and prenol polyethylene glycol The weight ratio of ether and distilled water is: 1:4:2.1:9.5:16.4, the lauryl amidopropyl betaine consumption is 1.1% of the prenol polyglycol ether weight, and the ammonium persulfate consumption is 0.28% of the weight of the prenol polyglycol ether, and the amount of the mercaptopropionic acid is 0.46% of the weight of the prenol polyglycol ether. After the reaction is completed, it is cooled to 25° C., and then 32% sodium hydroxide solution is added to adjust pH=7.2 to obtain a shrinkage-reducing polycarboxylate water-reducing agent.

Comparative Example 2

A shrinkage-reducing polycarboxylate water-reducing agent and a preparation method thereof are realized by the following steps:

(1) Preparation of polymerized monomer with shrinkage-reducing function: In a detachable temperature-controlled reactor equipped with a reflux condenser, agitator and a four-necked flask, add distilled water, molar salt and maleic anhydride, and heat to 75°C at the same time , 72% acrylic acid aqueous solution, 75% propylene oxide aqueous solution, 55% isoprenol aqueous solution were added dropwise through different openings in the mixture, and 15% sodium persulfate and 15% sodium bisulfite were added as The initiator participates in the reaction. The dropwise addition times of acrylic acid, propylene oxide, sodium persulfate and sodium bisulfite were respectively 70 minutes, 75 minutes, 70 minutes and 75 minutes. Adopt the mode of dropping the above-mentioned various solutions at the same time, after the dropping is completed, the obtained solution is further matured for 42 minutes at the same controlled temperature, and after the reaction is completed, it is allowed to stand for cooling, and the alkylene glycol/alkene is obtained through the above steps. Base ether/maleic anhydride shrinkage-reducing functional copolymer, wherein the weight ratio of molar salt, maleic anhydride, and sodium bisulfite is: 1:8:10; The weight ratio of the oxypropane aqueous solution, the isoprenol aqueous solution and the distilled water is 1:2.4:6.8:5.1:3.8:7.5.

(2) Preparation of shrinkage-reducing polycarboxylate water-reducing agent: In a detachable temperature-controlled reactor equipped with a reflux condenser, agitator and a four-necked bottle, add the shrinkage-reducing functional polymer monomer and distilled water into the four-necked bottle. , heat up to 40 ° C, stir for 27 minutes, add vinyl sulfonic acid after mixing it evenly, under nitrogen protection, heat and stir in a constant temperature water bath, when the reaction temperature reaches 70 ° C, slowly add prenol with a molecular weight of 2000 Polyethylene glycol ether and lauramidopropyl betaine aqueous solution, at the same time, slowly add ammonium persulfate and mercaptopropionic acid dropwise, the duration of adding the above four raw materials is controlled at 105 minutes, after the dropwise addition, the constant temperature reaction 5.5h, wherein the weight ratio of vinyl sulfonic acid, shrinkage-reducing functional polymer monomer, prenol polyglycol ether, and distilled water is: 1:3.9:6.2:17.3, and the lauroamidopropyl betaine Consumption is 1.3% by weight of prenol polyethylene glycol ether, described ammonium persulfate consumption is 0.35% by weight of prenol polyglycol ether, and described mercaptopropionic acid consumption is prenol polyethylene glycol ether 0.41% by weight of glycol ether. After the reaction is completed, it is cooled to 26° C., and then 32% sodium hydroxide solution is added to adjust pH=6.8 to obtain a shrinkage-reducing polycarboxylate water-reducing agent.

Comparative Example 3

A shrinkage-reducing polycarboxylate water-reducing agent and a preparation method thereof are realized by the following steps:

(1) Preparation of polymerized monomer with shrinkage-reducing function: In a detachable temperature-controlled reactor equipped with a reflux condenser, agitator and a four-necked flask, add distilled water, Mohr salt and maleic anhydride, and heat to 80°C at the same time , 72% acrylic acid aqueous solution, 75% propylene oxide aqueous solution, 55% isoprenol aqueous solution were added dropwise through different openings in the mixture, and 15% sodium persulfate and 15% sodium bisulfite were added as The initiator participates in the reaction. The dropwise addition times of acrylic acid, propylene oxide, sodium persulfate and sodium bisulfite were respectively 70 minutes, 75 minutes, 70 minutes and 75 minutes. Adopt the mode of dropping the above-mentioned various solutions at the same time, after the dropping is completed, the obtained solution is further matured for 42 minutes at the same controlled temperature, and after the reaction is completed, it is allowed to stand for cooling, and the alkylene glycol/alkene is obtained through the above steps. Base ether/maleic anhydride shrinkage-reducing functional copolymer, wherein the weight ratio of molar salt, maleic anhydride, and sodium bisulfite is: 1:8:10; The weight ratio of the oxypropane aqueous solution, the isoprenol aqueous solution and the distilled water is 1:2.4:6.8:5.5:3.8:7.5.

(2) Preparation of shrinkage-reducing polycarboxylate water-reducing agent: In a detachable temperature-controlled reactor equipped with a reflux condenser, agitator and a four-necked bottle, add the shrinkage-reducing functional polymer monomer and distilled water into the four-necked bottle. , heat up to 40°C, stir for 30 minutes, add dimethylaminoethyl methacrylate and methallyl sulfonic acid after mixing evenly, under nitrogen protection, heat and stir in a constant temperature water bath, when the reaction temperature reaches 75°C Begin to slowly add isoprenol polyglycol ether with a molecular weight of 2000 at the same time, and slowly add ammonium persulfate and mercaptopropionic acid dropwise at the same time. , constant temperature reaction 5.5h, wherein the weight ratio of described methallyl sulfonic acid, shrinkage-reducing functional polymerization monomer, dimethylaminoethyl methacrylate, prenyl polyglycol ether, distilled water is: 1: 4.2:2.1:6.2:17.3, the amount of the ammonium persulfate is 0.35% by weight of the prenol polyglycol ether, and the amount of the mercaptopropionic acid is 0.41% by the weight of the prenol polyglycol ether. After the reaction is completed, it is cooled to 26° C., and then 32% sodium hydroxide solution is added to adjust pH=6.8 to obtain a shrinkage-reducing polycarboxylate water-reducing agent.

Comparative Example 4

A polycarboxylate water-reducing agent without additional shrinkage-reducing functional monomers and a preparation method thereof are realized by the following steps:

In a detachable temperature-controlled reactor equipped with a reflux condenser, agitator and a four-necked flask, add distilled water to the four-necked flask, raise the temperature to 44°C, stir for 30 minutes, and add dimethylamino acrylate after mixing evenly. Ethyl ester and vinyl sulfonic acid were heated and stirred in a constant temperature water bath under the protection of nitrogen. When the reaction temperature reached 70 °C, the prenyl polyglycol ether with a molecular weight of 2000 and lauroamidopropyl betaine were slowly added. Aqueous solution, at the same time, ammonium persulfate and mercaptopropionic acid were slowly added dropwise, and the addition duration of the above four raw materials was controlled at 105 minutes. The weight ratio of methylaminoethyl ester, prenol polyglycol ether, distilled water is: 1:1.9:6.2:17.3, and the described lauroamidopropyl betaine consumption is the weight of prenol polyglycol ether 1.3% of the ammonium persulfate, the amount of the ammonium persulfate is 0.35% of the weight of the prenol polyglycol ether, and the amount of the mercaptopropionic acid is 0.41% of the weight of the prenol polyglycol ether. After the reaction is completed, it is cooled to 26°C, and then 32% sodium hydroxide solution is added to adjust pH=6.5, that is, a polycarboxylate water-reducing agent without additional shrinkage-reducing functional monomer is obtained.

Performance Testing

According to GB/T-8077-2012 "Concrete Admixture Homogeneity Test Method", JC/T2361-2016 "Mortar, Concrete Shrinkage Reducer", JC/T603-2008 "Cement Mortar Dry Shrinkage Test Method" and other relevant regulations , The performance tests of Examples 1-7 and Comparative Examples 1-4 were carried out, and their compressive strengths were carried out in accordance with GB/T5008-2016 "Standards for Test Methods of Mechanical Properties of Ordinary Concrete". The cement in the raw materials is commercially available P•O 32.5 grade, the fineness modulus of river sand is 2.5, the crushed stone is continuous graded crushed stone of 5~20mm, the fixed water-cement ratio is 0.29, and the shrinkage-reducing polycarboxylate water-reducing agent is mixed with The amount is 1.2% of the total mass of the cementitious material. The blank control group is the concrete without the shrinkage-reducing polycarboxylate water-reducing agent of the present invention. Other dosages of the blank control are the same as those of the example group. The final test results are shown in the table below.

From the performance test data of the above concrete, as a whole, after adding this shrinkage-reducing polycarboxylate superplasticizer, the compressive strength of the concrete increases to a certain extent at 7d and 28d. This is due to this shrinkage-reducing type. The molecular structure of polycarboxylate superplasticizer contains a large number of hydrophilic groups such as alcoholic hydroxyl groups, amides, and amino groups. During the polymerization process, there will be a cross-linking effect, which increases the steric hindrance effect of the system. This steric hindrance effect makes The water reducing agent of the invention has good dispersing performance in concrete, can better disperse the cement particles in the concrete system, fully stimulate the hydration of the cement particles, improve the utilization rate of the cement, so that the strength of the concrete at each age is improved. It can be seen from Examples 1-8 that after the alkylene glycol/alkenyl ether/maleic anhydride structural unit with shrinkage-reducing function is introduced into the molecular structure of the polycarboxylate water-reducing agent, this structural unit acts as a kind of The surface active active ingredients contribute to the shrinking function, which can reduce the surface tension of the liquid phase in the concrete capillary, reduce the negative pressure in the capillary, and reduce the shrinkage stress, thereby effectively reducing the shrinkage of concrete and the surface tension of the system. However, in Comparative Example 4, which did not introduce shrinkage-reducing functional structural units, its corresponding shrinkage-reducing effect and surface tension were not significantly improved compared to the blank group. The optimal choice is very critical, and the lack of any raw material will have a certain impact on the final compressive strength, slump retention effect, and shrinkage reduction effect.

In addition to the above-mentioned preferred embodiments, the present invention also has other embodiments, and those skilled in the art can make various changes and modifications according to the present invention, as long as they do not depart from the spirit of the present invention, they shall all belong to the definition of the appended claims of the present invention scope.

Claims (10)

1. a shrinkage-reducing type polycarboxylate water-reducing agent, comprising the active component of the following structure:

; Among them, a, b, c, d, x, y and z are all integers, and a=1～30, b=10～65, c=1～25, d=1～18, x=1～32, And x represents the average added moles of oxyalkylene groups (—R7—O—), y=1～20, and y represents the average added moles of oxyalkylene groups (—R8—O—), z= 5～27; R1 and R2 are -H or -CH3, R3 is an alkyl group of 1-2 carbons, R4 is -H or an alkyl group of 1-2 carbons, R5 is -H or -CH3, R6 is 1-2 carbons R7 is C2～C20 alkylene, R8 is C2～C4 alkylene, R9 is -H or 2～3 carbon alkyl, A is C1～C3 alkylene, M is C1～C3 alkylene Na or K or NH4. 2. a preparation method of a shrinkage-reducing polycarboxylate water-reducing agent, comprising the following steps: Step (1), preparation of shrinkage-reducing functional polymerized monomers: Add distilled water, molar salt and maleic anhydride into the reactor, and heat to 60℃～80℃; 70-74% acrylic acid aqueous solution, 73-77% propylene oxide aqueous solution, 53-57% isoprenol aqueous solution, 13-17% sodium persulfate, 13-17% sulfurous acid are added dropwise to the reactor Sodium hydrogen is used as an initiator to participate in the reaction, and the dropping time of acrylic acid, propylene oxide, sodium persulfate and sodium hydrogen sulfite is controlled within 70-80 minutes; After the dropwise addition is completed, the obtained solution is further aged for 40 to 70 minutes at the same controlled temperature, and after the reaction is completed, it is allowed to stand for cooling to obtain an alkylene glycol/alkenyl ether/maleic anhydride shrinkage-reducing functional copolymer, which is The structural units are as follows:

; Step (2), the preparation of shrinkage-reducing polycarboxylate water-reducing agent: Add the shrinkage-reducing functional polymerized monomer obtained in step (1) and distilled water into the reactor, heat up to 35°C to 45°C, and stir for 10 to 30 minutes; After the shrinkage-reducing functional polymer monomer and distilled water are evenly mixed, add unsaturated carboxylic acid alkyl ester and sulfonic acid group monomer, and under nitrogen protection, heat and stir in a constant temperature water bath; When the reaction temperature reaches 60 ℃ ~ 75 ℃, start to slowly add polyether macromonomer and dispersant aqueous solution, and at the same time slowly add initiator and molecular weight regulator, the adding duration of the above four raw materials is controlled at 90 ~ 120 minutes, after the dropwise addition is completed, the constant temperature reaction is performed for 4 to 6 hours; After the reaction is completed, it is cooled to 20°C to 30°C, and then 30 to 35% sodium hydroxide solution is added to adjust pH=6 to 8 to obtain a condensation-reducing polycarboxylate water-reducing agent. 3. The preparation method of shrinkage-reducing polycarboxylate water-reducing agent according to claim 2, characterized in that, in step (1), the weight ratio of the molar salt, maleic anhydride, and sodium bisulfite is: 1:5～10:8～18; the weight ratio of the sodium bisulfite, sodium persulfate, acrylic acid aqueous solution, propylene oxide aqueous solution, isoprenol aqueous solution, and distilled water is: 1:2～3:5.5～ 8.5:3.5～6:2.5～4.5:5.5～7.5. 4 . The method for preparing a shrinkage-reducing polycarboxylate water-reducing agent according to claim 2 , wherein in step (2), the unsaturated carboxylic acid alkyl ester comprises dimethylaminoethyl acrylate, methyl One or more of dimethylaminoethyl acrylate, dimethylaminopropyl acrylate, etc. are mixed in any proportion; the sulfonic acid-based monomer includes vinylsulfonic acid, methallylsulfonic acid, One or more of isoprenesulfonic acid, 3-allyloxy-2-hydroxypropanesulfonic acid, acrylamide-2-methylpropanesulfonic acid and salts of these acids mixed in any proportion . 5 . The method for preparing a shrinkage-reducing polycarboxylate water-reducing agent according to claim 2 , wherein in step (2), the polyether macromonomer comprises methoxy polyethylene glycol ether, isopentyl One or more of enol polyglycol ether, propenol polyglycol ether and isobutenol polyglycol ether are mixed in any proportion; the dispersant is alkylamide betaine. 6. The preparation method of the shrinkage-reducing polycarboxylate water-reducing agent according to claim 2, wherein in step (2), the initiator comprises hydrogen peroxide, ammonium persulfate, benzoyl peroxide, One or more of dimethyl azobisisobutyrate mixed in any proportion; the molecular weight regulator includes mercaptoethanol, mercaptoacetic acid, mercaptopropionic acid, isopropanol, dodecyl mercaptan One or more of the substances are mixed in any proportion. 7. the preparation method of shrinkage-reducing polycarboxylate water-reducing agent according to claim 5, is characterized in that, described dispersing agent comprises lauramidopropyl betaine, cocamidopropyl betaine, octadecamidopropyl betaine One or more of propyl betaine are mixed and mixed in any proportion. 8. the preparation method of shrinkage-reducing polycarboxylate water-reducing agent according to claim 2 or 4 or 5, is characterized in that, described sulfonic acid group monomer, shrinkage-reducing functional polymerization monomer, unsaturated carboxylic acid alkyl ester , the weight ratio of polyether macromonomer and distilled water is: 1:3.5～4.5:1.5～2.5:5.5～10:12～18; The weight ratio of carboxylate alkyl ester, polyether macromonomer and distilled water is 1:3.8-4.2:1.7-2.1:5.7-9.5:13.6-17.3. 9. the preparation method of the shrinkage-reducing polycarboxylate water-reducing agent according to claim 2 or 5 or 6 or 7, is characterized in that, described dispersant dosage is 0.5%～2% of polyether macromonomer weight, The dosage of the initiator is 0.2% to 0.7% of the weight of the polyether macromonomer, and the dosage of the molecular weight regulator is 0.3% to 0.8% of the weight of the polyether macromonomer; preferably, the dosage of the dispersant is polyether 0.6% to 1.3% of the weight of the macromonomer, the dosage of the initiator is 0.25% to 0.41% of the weight of the polyether macromonomer, and the dosage of the molecular weight regulator is 0.34% to 0.52% of the weight of the polyether macromonomer. 10. The preparation method of the shrinkage-reducing polycarboxylate water-reducing agent according to claim 2, characterized in that, in step (1), 72% acrylic acid aqueous solution, 75% propylene oxide aqueous solution, 55% acrylic acid aqueous solution, 55 % isoprenol aqueous solution, plus 15% sodium persulfate and 15% sodium bisulfite as initiators to participate in the reaction.