阅读说明：本技术 硫铝酸盐水泥用复合吸附型固体减水剂的制备方法 (Preparation method of composite adsorption type solid water reducing agent for sulphoaluminate cement ) 是由 刘晓 卢磊 宋晓飞 王子明 许谦 白夏冰 赖光洪 管佳男 于 2019-11-20 设计创作，主要内容包括：本发明涉及一种硫铝酸盐水泥用复合吸附型固体减水剂的制备方法,通过先合成线形固体减水剂再合成梳形固体减水剂而后复合吸附的方法制备一种固体减水剂,即不饱和羧酸与不饱和磷酸酯先共聚合,同时自制多羟基侧链大单体并与不饱和聚氧乙烯醚、阳离子单体、阴离子单体共聚合,再将各聚合产物充分混合研磨制得复合吸附型固体减水剂。本发明方法所得复合吸附型减水剂结构新颖独特,性能优异,可广泛应用于硫铝酸盐水泥中提升净浆流动性及其保持能力,延长操作时间,很好地解决了硫铝酸盐水泥浆体凝结硬化过快、流动性损失快等问题,并且制备成固体产品形态有利于应用于修补材料中,表现出比常规减水剂更为优异的作用效果和应用适用性,市场前景广阔。(The invention relates to a preparation method of a composite adsorption type solid water reducing agent for sulphoaluminate cement, which is characterized in that a solid water reducing agent is prepared by firstly synthesizing a linear solid water reducing agent, then synthesizing a comb-shaped solid water reducing agent and then carrying out composite adsorption, namely unsaturated carboxylic acid and unsaturated phosphate ester are copolymerized firstly, and meanwhile, a polyhydroxy side chain macromonomer is copolymerized with unsaturated polyoxyethylene ether, a cationic monomer and an anionic monomer, and then all polymerization products are fully mixed and ground to prepare the composite adsorption type solid water reducing agent. The composite adsorption type water reducing agent obtained by the method has a novel and unique structure and excellent performance, can be widely applied to sulphoaluminate cement to improve the fluidity and the retention capacity of the slurry, prolongs the operation time, well solves the problems of too fast setting and hardening, fast fluidity loss and the like of sulphoaluminate cement slurry, is prepared into a solid product form, is beneficial to being applied to repairing materials, shows more excellent action effect and application applicability than the conventional water reducing agent, and has wide market prospect.)

1. A preparation method of a composite adsorption type solid water reducing agent for sulphoaluminate cement is characterized in that the conditions and the steps for preparing the solid water reducing agent for sulphoaluminate cement by firstly synthesizing a linear solid water reducing agent, then synthesizing a comb-shaped solid water reducing agent and then carrying out composite adsorption are as follows:

(1) synthesizing a linear solid water reducing agent: firstly, adding a carboxylic acid monomer into a reactor, stirring and heating to 30-120 ℃, then dropwise adding a mixture of unsaturated phosphate, a chain transfer agent and an organic base for 1-12 hours, adding an initiator for 5-20 times, stirring for 5-20 minutes at intervals of each time, continuing to perform constant-temperature reaction for 1-6 hours after dropwise adding is finished, stopping reaction, and cooling to 15-30 ℃ to obtain a linear solid water reducing agent;

(2) synthesizing a side chain of the comb-shaped solid water reducing agent: firstly, uniformly mixing fatty acid vinyl ester and an organic solvent, adding a transition metal halide, an unsaturated initiator and a ligand, filling nitrogen in an ice water bath for 3-5 times of oxygen removal for 5-20 minutes, stirring for 10-30 minutes until the mixture is uniformly mixed, heating to 10-100 ℃ under the protection of nitrogen for polymerization reaction for 3-36 hours, desalting, carrying out reduced pressure distillation to remove the organic solvent, adding an alcohol solvent, stirring and heating to 20-80 ℃, adding an inorganic base, carrying out alcoholysis for 10-120 minutes, and removing the alcohol solvent after the alcoholysis is finished to obtain a comb-shaped solid water reducer side chain;

(3) synthesizing a comb-shaped solid water reducing agent: adding the side chain of the comb-shaped solid water reducing agent obtained in the step (2) and unsaturated polyoxyethylene ether into a reactor, heating to 40-100 ℃, stirring, dropwise adding a mixture of a quaternary amine monomer, a carboxylic acid monomer, unsaturated phosphate ester, a chain transfer agent and an organic base for 1-12 hours, adding an initiator for 5-20 times, stirring for 5-20 minutes at intervals after each time of adding, continuing to perform constant-temperature reaction for 1-6 hours after the dropwise adding is finished, stopping the reaction, and cooling to 15-30 ℃ to obtain the comb-shaped solid water reducing agent;

(4) preparing a composite adsorption type solid water reducer: putting the solid water reducing agent obtained in the step (1) into a planetary ball milling tank, sealing and fixing the planetary ball milling tank in a planetary ball mill, controlling the temperature in the ball mill to 10-30 ℃, sampling every 10-30min to measure the particle size distribution, taking out the sample until the median particle size reaches 200 plus materials and 300nm, adding the sample into a flask, heating to 60-120 ℃, uniformly stirring, grinding the solid water reducing agent obtained in the step (3) according to the same steps until the median particle size reaches 200 plus materials and 300nm, taking out the sample and adding the sample into the flask 10-18 times, stirring for 3-5 minutes at intervals of each time, reacting at constant temperature for 1-3 hours after all the solid water reducing agent is added, and cooling to 15-30 ℃ to obtain the composite adsorption type solid water reducing agent;

wherein the unsaturated phosphate ester in the step (1) is one or more of 10- (2-methacryloyloxy) monodecanyl phosphate, phosphonic acid-B-styrene ester, acrylate phosphate and hydrogen phosphate di (methacryloyloxyethyl) ester; the carboxylic acid monomer in the step (1) is one or more of acrylic acid, methacrylic acid and fumaric acid, and the molar ratio of the amount of the carboxylic acid monomer to the unsaturated phosphate in the step (1) is 0-3: 1; the chain transfer agent in the step (1) is mercaptoethanol, mercaptoacetic acid or mercaptopropionic acid, and the molar ratio of the dosage of the chain transfer agent to the unsaturated phosphate in the step (1) is 0.05-0.2: 1; the organic base in the step (1) is one or more of methylamine, urea, ethylamine, ethylenediamine, dimethylamine, trimethylamine and triethylamine, and the mass ratio of the dosage to the unsaturated phosphate in the step (1) is 0.04-0.08: 1; the initiator in the step (1) is ammonium persulfate, potassium persulfate, sodium persulfate, hydrogen peroxide-ascorbic acid, hydrogen peroxide-sodium formaldehyde sulfoxylate, hydrogen peroxide-sodium hypophosphite, ammonium persulfate-sodium sulfite or ammonium persulfate-sodium bisulfite, and the molar ratio of the amount of the initiator to the unsaturated phosphate in the step (1) is 0.05-1: 1;

the unsaturated initiator in the step (2) is (methyl) allyl bromide, (methyl) allyl chloride, 1-bromo-3-methyl-2-butene, 1-chloro-3-methyl-2-butene, 2-bromoethyl acrylate, 2-chloroacrylic acid ethyl ester, 2-bromo-3-methyl-butenoate, 2-chloro-3-methyl-butenoate, 1-bromo-4-methyl-3-penten-2-one or 1-chloro-4-methyl-3-penten-2-one; the fatty acid vinyl ester in the step (2) is vinyl acetate, vinyl propionate or vinyl butyrate, and the molar ratio of the usage amount to the unsaturated initiator in the step (2) is 10-200: 1; the solvent in the step (2) is toluene, p-xylene, dimethylformamide or ethanol, and the mass ratio of the dosage to the fatty acid vinyl ester is 2-10: 1; the transition metal halide in the step (2) is cuprous bromide, cuprous chloride, ferrous bromide or ferrous chloride, and the molar ratio of the consumption to the unsaturated initiator in the step (2) is 1-4: 1; the ligand in the step (2) is one or more of N, N, N, N, N-pentamethyl divinyl triamine, 2-bipyridine, 1,4,7,10, 10-hexamethyl triethylene tetramine, tetra [ (2-pyridyl) methyl ] ethylenediamine and tri [2- (dimethylamino) ethyl ] amine, and the molar ratio of the used amount to the transition metal halide in the step (2) is 1-1.5: 1; the alcohol solvent in the step (2) is methanol, ethanol or propanol, and the molar ratio of the dosage of the alcohol solvent to the fatty acid vinyl ester in the step (2) is 2-5: 1; the inorganic base in the step (2) is sodium hydroxide or potassium hydroxide, and the molar ratio of the use amount of the inorganic base to the alcohol solvent in the step (2) is 0.001-0.01: 1;

the unsaturated phosphate in the step (3) is one or more of 10- (2-methacryloyloxy) monodecanyl phosphate, phosphonic acid-B-styrene ester, acrylate phosphate and hydrogen phosphate di (methacryloyloxyethyl) ester; the unsaturated polyoxyethylene ether in the step (3) is allyl polyoxyethylene ether, isobutenyl polyoxyethylene ether or isopentenyl polyoxyethylene ether, and the molar ratio of the dosage to the unsaturated phosphate in the step (3) is 0.125-1: 1; the carboxylic acid monomer in the step (3) is one or more of acrylic acid, methacrylic acid and fumaric acid, and the molar ratio of the amount of the carboxylic acid monomer to the unsaturated phosphate in the step (3) is 0.3-0.5: 1; the quaternary ammonium monomer in the step (3) is allyl trimethyl ammonium chloride, trimethyl vinyl ammonium bromide or methacryloyloxyethyl trimethyl ammonium chloride, and the molar ratio of the dosage to the unsaturated phosphate in the step (3) is 1-5: 1; the chain transfer agent in the step (3) is mercaptoethanol, mercaptoacetic acid or mercaptopropionic acid, and the molar ratio of the dosage of the chain transfer agent to the unsaturated phosphate in the step (3) is 0.02-0.1: 1; the organic base in the step (3) is one or more of methylamine, urea, ethylamine, ethylenediamine, dimethylamine, trimethylamine and triethylamine, and the mass ratio of the dosage to the unsaturated phosphate in the step (3) is 0.05-0.1: 1; the initiator in the step (3) is ammonium persulfate, potassium persulfate, sodium persulfate, hydrogen peroxide-ascorbic acid, hydrogen peroxide-sodium formaldehyde sulfoxylate, hydrogen peroxide-sodium hypophosphite, ammonium persulfate-sodium sulfite or ammonium persulfate-sodium bisulfite, and the molar ratio of the amount of the initiator to the unsaturated phosphate in the step (3) is 0.04-0.08: 1; the molar ratio of the side chain of the comb-shaped solid water reducing agent obtained in the step (2) to the unsaturated polyoxyethylene ether obtained in the step (3) is 1-3: 1.

2. The composite adsorption type solid water reducing agent prepared by the method of claim 1, which is characterized by having a molecular structural formula as follows:

wherein m is an integer of 10 to 150, and n is an integer of 10 to 150; r₁Is H or COOH; r₂Is phenyl or H; r₃Is CH₃H or none; r₄Is a hydroxydecyl ester group, a hydroxyethyl ester group or none; r₅Is methacryloyloxyethyl or H; r₆Is CH₂Ethyl ester group or none; r₇Is CH₂Or CH₂CH₂；R₈Is H, CH₃Or COOM, wherein M is H, methyl, ethyl, or an alkali metal ion; r₉Is CH₂Carboxymethyl or none; r₁₀Br or Cl.

Technical Field

The invention relates to the technical field of solid water reducing agents for sulphoaluminate cement, in particular to a specific preparation method for preparing a solid water reducing agent by preparing a linear solid water reducing agent by adopting unsaturated carboxylic acids and unsaturated phosphate monomers, preparing a comb-shaped solid water reducing agent and then performing composite adsorption on the comb-shaped solid water reducing agent.

Background

In recent years, along with the increasing requirements of building material industry on energy conservation and environmental protection, the sulphoaluminate cement draws more and more attention of academia and industry, in particular to the high belite sulphoaluminate cement derived from the sulphoaluminate cement, the calcination temperature of clinker is lower, the consumption of limestone raw materials is low, and the energy consumption and CO in the clinker calcination process are reduced₂The emission amount is significantly lower than that of the common Portland cement (OPC) which is most commonly used at present, so that the sulphoaluminate cement is considered as the most promising alternative cementing material and becomes a research hotspot in the field of energy-saving and consumption-reducing cements. As is well known, the main mineral of sulphoaluminate cement is anhydrous calcium sulphoaluminate (C)₄A₃S) and dicalcium silicate (C)₂S) reacts with gypsum rapidly in the early stage of hydration to generate ettringite (AFt), which is beneficial to application in the field with the demand of early strength and rapid hardening, but the cement paste has higher hydration speed, so that the cement paste is applicable to the field with the demand of early strength and rapid hardeningThe body is easy to have great loss with time, and sometimes even can not meet the basic construction requirements. In order to ensure that the sulphoaluminate cement obtains better working performance and sufficient construction time under the condition of ensuring the strength, chemical additives are often added for adjustment in practical application, but the existing research shows that the additives of the traditional portland cement system are not suitable for the sulphoaluminate cement system.

After the sulphoaluminate cement is developed for more than 40 years, the fluidity and the constructability are always the brake elbows for the application and the popularization of the sulphoaluminate cement. The faster hydration and setting rates of sulphoaluminate cement result in a nearly complete loss of fluidity of the cement slurry in a short period of time. In general, the fluidity improvement of cement-based materials is realized by adding chemical additives, and current researches show that the fluidity improvement effect of the sulphoaluminate cement system is not obvious no matter the commonly used inorganic additives or high-efficiency water reducing agents, and the performance of the sulphoaluminate cement is greatly influenced if the adding amount is increased forcibly, because the sulphoaluminate cement has faster hydration behavior compared with common Portland cement, and the generated hydration product is AFt crystal instead of hydrated calcium silicate (C-S-H). On the premise of ensuring a plurality of advantages of sulphoaluminate cement, in order to further improve the workability of the sulphoaluminate cement, a chemical admixture matched with a sulphoaluminate cement system is obtained, and based on the application background that the sulphoaluminate cement is mostly used for solid repair materials, the solid water reducing agent with the composite adsorption structure is designed, the advantage that a linear structure is easy to quickly adsorb is firmly anchored on the surface of sulphoaluminate cement particles, the initial dispersity of the sulphoaluminate cement particles is improved, and based on charge design, the amphoteric comb-shaped water reducing agent is compositely adsorbed on the surface of the linear structure, so that the overall steric hindrance of the water reducing agent is increased, and the self-synthesized side chain with the polyhydroxy structure can effectively delay the hydration and condensation rate of the cement particles and keep a long dispersion effect.

Patent CN 108409267A (published: 2018, 08.17.A) reports a preparation method of early strength sulphoaluminate cement slurry easy to pump, and high calcium fly ash and lithium carbonate are added into a sulphoaluminate cement system as additive components to improve the fluidity of the sulphoaluminate cement system so as to meet the requirements of pumping and the like. The invention utilizes substances such as high-calcium fly ash, lithium carbonate and the like to modify the fluidity of the sulphoaluminate cement, ensures the early strength of the sulphoaluminate cement, and has obvious application value, but the admixture is prepared by only adopting the physical compounding of inorganic matters, does not utilize the advantages of organic polymer admixtures in the aspects of molecular structure design, adjustability, controllability and the like, and is difficult to ideally control the workability and the setting time of the sulphoaluminate cement according to the actual application requirements.

Patent CN 107304109A (published: 10/31/2017) reports a novel retarder for sulphoaluminate cement and a preparation method thereof, and maleic anhydride, tungstic acid, hydrogen peroxide, potassium hydroxide, anhydrous boric acid, sodium gluconate and sodium tripolyphosphate are compounded according to a certain proportion to prepare the retarder for sulphoaluminate cement. The retarder for sulphoaluminate cement prepared by the invention has the functions of improving the fluidity of sulphoaluminate cement and prolonging the initial setting and final setting time in a way of compounding organic and inorganic additives. However, the retarder is only prepared by physical compounding instead of chemical polymerization, has limited effect, and cannot realize the purposes of retarding and improving the fluidity by utilizing the advantage of steric hindrance of high-molecular polymers.

A composite set control agent for improving the working performance of sulphoaluminate cement is reported in patent CN 103288372A (published: 09/11/2013), and sodium citrate, sodium gluconate, aluminum sulfate and lithium hydroxide are compounded according to a certain proportion to obtain the sulphoaluminate cement set control agent. The invention realizes the extension of the initial setting time and the improvement of the workability of the sulphoaluminate cement by compounding the sodium citrate and the sodium gluconate, and obtains favorable feasibility for the construction operation of the sulphoaluminate cement. However, the retarder is essentially a physical combination of two retarders, no subversive transformation and innovation are realized in the fields of molecular structure and the like, the adaptability in the sulphoaluminate cement is poor, the compounding ratio of the composite retarder is complex, and the functional design and preparation of the special chemical admixture for the sulphoaluminate cement cannot be realized from the aspects of polymer molecular structure, charge electrical property and the like.

The admixture components for sulphoaluminate cements described in most patents have the effect of increasing the fluidity and prolonging the setting time. However, the products obtained by the preparation methods all have certain defects, from the perspective of chemical reaction, researchers mostly adopt a physical mixing mode to prepare the chemical admixture, which is essentially the compounding of various inorganic or organic retarders, and the preparation of the chemical admixture for the sulphoaluminate cement cannot be realized by a mode of preparing a high molecular product through polymerization reaction. Although the high molecular chemical admixture of the traditional portland cement system is not suitable for the sulphoaluminate cement, the molecular structure design and the charge functional group design of the polymer prove that the improvement of the application performance of the polymer to the sulphoaluminate cement can be synergistically improved. Therefore, the synthetic polymer is required to be fundamentally innovated at the molecular structure level, a linear structure water reducing agent with rapid adsorption capacity and a comb structure water reducing agent with strong steric hindrance are innovatively synthesized without being limited by the design route of the traditional water reducing agent, and the composite adsorption type water reducing agent is prepared in a charge adsorption mode, so that the composite adsorption type water reducing agent has good initial fluidity of cement slurry, excellent slurry fluidity holding capacity and slow setting effect, is beneficial to industrial production and popularization and application, and is not reported at home and abroad in relation to the aspect.

Disclosure of Invention

The invention aims to provide a preparation process of a composite adsorption type solid water reducing agent for sulphoaluminate cement, which comprises the steps of carrying out free radical copolymerization on an unsaturated carboxylic acid monomer and an unsaturated phosphate monomer to obtain a linear solid water reducing agent, simultaneously self-preparing a side chain macromonomer with polyhydroxy, copolymerizing the side chain macromonomer with unsaturated polyoxyethylene ether macromonomer, a cationic monomer and an anionic monomer to obtain a comb-shaped solid water reducing agent, and finally fully mixing and grinding the linear solid water reducing agent and the comb-shaped solid water reducing agent to obtain the composite adsorption type solid water reducing agent for sulphoaluminate cement with excellent performance. The invention designs and synthesizes the linear solid water reducing agent with higher anionic charge density in advance from the theory of molecular structure design and charge design, utilizes the characteristic of quick adsorption to improve the initial fluidity of the sulphoaluminate cement slurry, the comb-shaped solid water reducing agent with amphoteric charges and polyhydroxy side chains is designed and synthesized, the characteristics of high steric hindrance and strong hydrogen bonds of the comb-shaped solid water reducing agent for hindering hydration nucleation are utilized, the flow retentivity and the slow setting effect of the sulphoaluminate cement slurry are improved, the anionic linear solid water reducing agent and the amphoteric comb-shaped solid water reducing agent are compositely adsorbed together to prepare the novel solid water reducing agent with multiple effects of high fluidity, high slow setting and the like, the aim of improving the workability of the water reducing agent through molecular topological structure modification and assembly adsorption is fulfilled, and the application of polymer structure-performance research in the field of chemical admixtures is enriched. The composite adsorption type solid water reducing agent for sulphoaluminate cement synthesized by the method is different from the structure of a conventional water reducing agent, the linear structure part of the composite adsorption type solid water reducing agent can be quickly adsorbed on the surface of cement particles to improve the initial dispersing ability, and the connected comb-shaped structure part can maintain the adsorption holding ability and inhibit the hydration rate of cement, so that the problems of too fast setting and hardening, fast fluidity loss and the like of sulphoaluminate cement slurry are well solved, and the prepared solid product form is favorable for being applied to sulphoaluminate cement repair materials and shows more excellent action effect and application applicability than the conventional water reducing agent.

The invention provides a preparation method of a composite adsorption type solid water reducing agent for sulphoaluminate cement, which is used for preparing a solid water reducing agent material for sulphoaluminate cement by firstly synthesizing a linear solid water reducing agent, then synthesizing a comb-shaped solid water reducing agent and then carrying out composite adsorption, and comprises the following conditions and steps:

(1) synthesizing a linear solid water reducing agent: firstly, adding a carboxylic acid monomer into a reactor, stirring and heating to 30-120 ℃, then dropwise adding a mixture of unsaturated phosphate, a chain transfer agent and an organic base for 1-12 hours, adding an initiator for 5-20 times, stirring for 5-20 minutes at intervals of each time, continuing to perform constant-temperature reaction for 1-6 hours after dropwise adding is finished, stopping reaction, and cooling to 15-30 ℃ to obtain a linear solid water reducing agent;

(2) synthesizing a side chain of the comb-shaped solid water reducing agent: firstly, uniformly mixing fatty acid vinyl ester and an organic solvent, adding a transition metal halide, an unsaturated initiator and a ligand, filling nitrogen in an ice water bath for 3-5 times of oxygen removal for 5-20 minutes, stirring for 10-30 minutes until the mixture is uniformly mixed, heating to 10-100 ℃ under the protection of nitrogen for polymerization reaction for 3-36 hours, desalting, carrying out reduced pressure distillation to remove the organic solvent, adding an alcohol solvent, stirring and heating to 20-80 ℃, adding an inorganic base, carrying out alcoholysis for 10-120 minutes, and removing the alcohol solvent after the alcoholysis is finished to obtain a comb-shaped solid water reducer side chain;

(3) synthesizing a comb-shaped solid water reducing agent: adding the side chain of the comb-shaped solid water reducing agent obtained in the step (2) and unsaturated polyoxyethylene ether into a reactor, heating to 40-100 ℃, stirring, dropwise adding a mixture of a quaternary amine monomer, a carboxylic acid monomer, unsaturated phosphate ester, a chain transfer agent and an organic base for 1-12 hours, adding an initiator for 5-20 times, stirring for 5-20 minutes at intervals after each time of adding, continuing to perform constant-temperature reaction for 1-6 hours after the dropwise adding is finished, stopping the reaction, and cooling to 15-30 ℃ to obtain the comb-shaped solid water reducing agent;

(4) preparing a composite adsorption type solid water reducer: putting the solid water reducing agent obtained in the step (1) into a planetary ball milling tank, sealing and fixing the planetary ball milling tank in a planetary ball mill, controlling the temperature in the ball mill to 10-30 ℃, sampling every 10-30min, measuring the particle size distribution, taking out after grinding until the median particle size is 200-plus-material 300nm, adding the solid water reducing agent into a flask, heating to 60-120 ℃, uniformly stirring, grinding the solid water reducing agent obtained in the step (3) according to the same steps until the median particle size is 200-plus-material 300nm, taking out and adding into the flask 10-18 times, stirring for 3-5 minutes at intervals of each time of feeding, reacting at constant temperature for 1-3 hours after all the solid water reducing agent is added, and cooling to 15-30 ℃ to obtain the composite adsorption type solid water reducing agent.

Wherein the unsaturated phosphate ester in the step (1) is one or more of 10- (2-methacryloyloxy) monodecanyl phosphate, phosphonic acid-B-styrene ester, acrylate phosphate and hydrogen phosphate di (methacryloyloxyethyl) ester; the carboxylic acid monomer in the step (1) is one or more of acrylic acid, methacrylic acid and fumaric acid, and the molar ratio of the amount of the carboxylic acid monomer to the unsaturated phosphate in the step (1) is 0-3: 1; the chain transfer agent in the step (1) is mercaptoethanol, mercaptoacetic acid or mercaptopropionic acid, and the molar ratio of the dosage of the chain transfer agent to the unsaturated phosphate in the step (1) is 0.05-0.2: 1; the organic base in the step (1) is one or more of methylamine, urea, ethylamine, ethylenediamine, dimethylamine, trimethylamine and triethylamine, and the mass ratio of the dosage to the unsaturated phosphate in the step (1) is 0.04-0.08: 1; the initiator in the step (1) is ammonium persulfate, potassium persulfate, sodium persulfate, hydrogen peroxide-ascorbic acid, hydrogen peroxide-sodium formaldehyde sulfoxylate, hydrogen peroxide-sodium hypophosphite, ammonium persulfate-sodium sulfite or ammonium persulfate-sodium bisulfite, and the molar ratio of the amount of the initiator to the unsaturated phosphate in the step (1) is 0.05-1: 1.

The unsaturated initiator in the step (2) is (methyl) allyl bromide, (methyl) allyl chloride, 1-bromo-3-methyl-2-butene, 1-chloro-3-methyl-2-butene, 2-bromoethyl acrylate, 2-chloroacrylic acid ethyl ester, 2-bromo-3-methyl-butenoate, 2-chloro-3-methyl-butenoate, 1-bromo-4-methyl-3-penten-2-one or 1-chloro-4-methyl-3-penten-2-one; the fatty acid vinyl ester in the step (2) is vinyl acetate, vinyl propionate or vinyl butyrate, and the molar ratio of the usage amount to the unsaturated initiator in the step (2) is 10-200: 1; the solvent in the step (2) is toluene, p-xylene, dimethylformamide or ethanol, and the mass ratio of the dosage to the fatty acid vinyl ester is 2-10: 1; the transition metal halide in the step (2) is cuprous bromide, cuprous chloride, ferrous bromide or ferrous chloride, and the molar ratio of the consumption to the unsaturated initiator in the step (2) is 1-4: 1; the ligand in the step (2) is one or more of N, N, N, N, N-pentamethyl divinyl triamine, 2-bipyridine, 1,4,7,10, 10-hexamethyl triethylene tetramine, tetra [ (2-pyridyl) methyl ] ethylenediamine and tri [2- (dimethylamino) ethyl ] amine, and the molar ratio of the used amount to the transition metal halide in the step (2) is 1-1.5: 1; the alcohol solvent in the step (2) is methanol, ethanol or propanol, and the molar ratio of the dosage of the alcohol solvent to the fatty acid vinyl ester in the step (2) is 2-5: 1; the inorganic base in the step (2) is sodium hydroxide or potassium hydroxide, and the molar ratio of the use amount of the inorganic base to the alcohol solvent in the step (2) is 0.001-0.01: 1.

The unsaturated phosphate in the step (3) is one or more of 10- (2-methacryloyloxy) phosphoric acid monodecanyl ester, phosphonic acid-B-styrene ester, acrylate phosphate and hydrogen phosphate di (methacryloyloxyethyl) ester; the unsaturated polyoxyethylene ether in the step (3) is allyl polyoxyethylene ether, isobutenyl polyoxyethylene ether or isopentenyl polyoxyethylene ether, and the molar ratio of the dosage to the unsaturated phosphate in the step (3) is 0.125-1: 1; the carboxylic acid monomer in the step (3) is one or more of acrylic acid, methacrylic acid and fumaric acid, and the molar ratio of the amount of the carboxylic acid monomer to the unsaturated phosphate in the step (3) is 0.3-0.5: 1; the quaternary ammonium monomer in the step (3) is allyl trimethyl ammonium chloride, trimethyl vinyl ammonium bromide or methacryloyloxyethyl trimethyl ammonium chloride, and the molar ratio of the dosage to the unsaturated phosphate in the step (3) is 1-5: 1; the chain transfer agent in the step (3) is mercaptoethanol, mercaptoacetic acid or mercaptopropionic acid, and the molar ratio of the dosage of the chain transfer agent to the unsaturated phosphate in the step (3) is 0.02-0.1: 1; the organic base in the step (3) is one or more of methylamine, urea, ethylamine, ethylenediamine, dimethylamine, trimethylamine and triethylamine, and the mass ratio of the dosage to the unsaturated phosphate in the step (3) is 0.05-0.1: 1; the initiator in the step (3) is ammonium persulfate, potassium persulfate, sodium persulfate, hydrogen peroxide-ascorbic acid, hydrogen peroxide-sodium formaldehyde sulfoxylate, hydrogen peroxide-sodium hypophosphite, ammonium persulfate-sodium sulfite or ammonium persulfate-sodium bisulfite, and the molar ratio of the amount of the initiator to the unsaturated phosphate in the step (3) is 0.04-0.08: 1; the molar ratio of the side chain of the comb-shaped solid water reducing agent obtained in the step (2) to the unsaturated polyoxyethylene ether obtained in the step (3) is 1-3: 1.

Sampling every 10-30min in the ball milling process in the step (4) to measure the particle size distribution until the particle size reaches 200-300 nm.

The composite adsorption type solid water reducing agent is characterized in that the molecular structural formula is as follows:

wherein m is an integer of 10 to 150, and n is an integer of 10 to 150; r₁Is H or COOH; r₂Is phenyl or H; r₃Is CH₃H or none; r₄Is a hydroxydecyl ester group, a hydroxyethyl ester group or none; r₅Is methacryloyloxyethyl or H; r₆Is CH₂Ethyl ester group or none; r₇Is CH₂Or CH₂CH₂；R₈Is H, CH₃Or COOM, wherein M is H, methyl, ethyl, or an alkali metal ion; r₉Is CH₂Carboxymethyl or none; r₁₀Br or Cl.

Compared with the prior art, the method of the invention has the following beneficial effects:

1. from the perspective of a molecular structure, the composite adsorption type solid water reducing agent synthesized by the invention compounds an anionic linear structure and an amphoteric comb-shaped structure together through charge adsorption, and is innovation and breakthrough in the design direction of the molecular structure of the water reducing agent, wherein the anionic linear structure water reducing agent is firmly anchored on the surface of cement particles, a considerable adsorption area is rapidly formed through high charge density, and the dispersibility of the connected comb-shaped structure water reducing agent on the cement particles can be improved through strong space steric resistance. On the one hand, anionic linear moieties are reacted with Ca²⁺To reduce Ca in the cement pore solution²⁺The generation of the ettringite is delayed; on the other hand, the comb-shaped structure part greatly increases the thickness of the adsorption layer and shows excellent characteristics in the aspect of inhibiting the rapid hydration of the sulphoaluminate cement.

2. Based on the molecular structure design theory, the invention synthesizes polyhydroxy side chain macromonomer in the mode of atom transfer radical polymerization and alcoholysis, and then combines unsaturated polyoxyethylene ether side chain macromonomer to copolymerize with anionic monomer and cationic monomer to form two side chain type amphoteric comb-shaped structure water reducing agents, thereby enriching the side chain types of the water reducing agents. Wherein, the polyoxyethylene ether side chain mainly provides steric hindrance and a solvation water film, and contributes to excellent fluidity retention capacity; the polyhydroxy side chain mainly provides a hydrogen bond effect, has a remarkable inhibiting effect on hydration nucleation of cement particles, contributes to an excellent retarding effect and prolongs construction operation time, and provides research ideas and technical guidance for subsequent development of new water reducing agent materials.

3. From the aspect of engineering application, compared with the traditional solution polymerization method, the method disclosed by the invention is prepared under the condition of completely not using a solvent, the obtained polymerization product is a solid water reducing agent with the concentration of 100%, the product obtained after the step of grinding into powder can be mixed with sulphoaluminate cement, and the mixture can be applied to a plurality of fields such as mortar repair in batches, so that the performance of the mortar is greatly improved, the requirements of various use functions are met, and meanwhile, the method has the advantages of quick construction, material saving and convenience in transportation, the transportation cost is greatly reduced, and the solid water reducing agent does not delaminate after standing at high concentration, is a solid water reducing agent with unique advantages and distinct characteristics, and has good market competitiveness and application prospect.

4. From the aspect of synthesis technology, the method has the advantages of simple synthesis process, simple and common reaction raw materials, common operation process means of copolymerization, no need of complex steps or special reactions, enrichment of the preparation method for synthesizing the functional water reducing agent, high efficiency, convenience, economy and energy conservation, and easy realization of industrial production. The synthesis process has no special requirement on equipment, does not depend on a special catalyst, has the advantages of strong molecular designability, controllable molecular weight, narrow molecular weight distribution, high polymerization degree and the like, and has good popularization value.

5. The composite adsorption type solid water reducing agent synthesized by the method shows excellent effect in sulphoaluminate cement, the particle size of the particles is obviously reduced through detection of a laser particle sizer, the product system is stable in state, the product does not deteriorate after long-term storage, the application performance is not influenced, the obtained product still has excellent performance indexes, the product can be applied to the fields of fine chemical engineering, surfactants and the like in a diversified and expanded manner, the new trend of the industry is favorably led, the technical progress of the industry is promoted, and the economic and social benefits are good.

6. The preparation process is safe and environment-friendly, has no solvent poison, low cost, less energy consumption, cleanness and no pollution, and part of raw materials used in each step can be recycled, so that the preparation cost is greatly saved, and the preparation method conforms to the concepts of sustainable preparation, energy conservation and environmental protection. Meanwhile, the solvent-free reaction system still has lower viscosity, the uniformity of the system can be improved, and higher reaction rate and conversion rate are realized. The controllable synthesis activity of the used raw materials is high, which is beneficial to the large-scale popularization and application of the synthesized product, and the market share and the occupation amount of the solid water reducing agent for the sulphoaluminate cement are increased.

Drawings

FIG. 1 is a schematic view of the structure of the water reducing agent of the present invention.

Detailed Description

The present invention will be described in further detail with reference to examples, but the practice of the present invention is not limited thereto.