A highly adaptable amphoteric phosphate-based water reducing agent and its preparation method

Abstract

The present invention discloses a highly adaptable amphoteric phosphate-based water reducer and a preparation method thereof. The highly adaptable amphoteric phosphate-based water reducer of the present invention is obtained by random copolymerization of an amphoteric phosphate monomer C having both an unsaturated quaternary ammonium salt cation and a phosphate group, an unsaturated carboxylic acid monomer D, and a polyoxyethylene ether macromonomer E; the unsaturated quaternary ammonium salt cation in the amphoteric phosphate monomer C is introduced by nucleophilic substitution of N-alkyl diethanolamine A with a halogenated olefin, and the phosphate group is derived from a phosphate ester structure introduced by the hydroxyl group of the alkanolamine under the action of a phosphorylation reagent. The cations and phosphate anions in the water reducer of the present invention can be adsorbed on the hydration products with different charge properties of C3A or C3S, C2S at the same time. The strong adsorption performance of the phosphate group enables the amphoteric phosphate-based water reducer to have high adaptability in different cementitious materials and good tolerance to materials with a relatively high mud content, and has good water-reducing and slump-retention properties.

Description

Technical Field

[0001] The present invention belongs to the technical field of polycarboxylate superplasticizers for cement concrete, and particularly relates to a highly adaptable amphoteric phosphoric acid-based superplasticizer and a preparation method thereof. Background Art

[0002] Polycarboxylate superplasticizers (PCE) have become the most widely used admixtures in the world due to their high water reduction rate, environmental friendliness, and strong molecular designability. However, with the increasingly fierce market competition of polycarboxylate superplasticizers, in order to reduce production costs and improve the competitive advantage of products, the water reduction rate of polycarboxylate superplasticizers in the market has increased year by year, resulting in an increasingly prominent sensitivity of PCE. Especially in recent years, with the rapid growth of infrastructure construction and real estate development projects in China, under the situation of the gradual scarcity of natural sandstone resources and the continuous strengthening of mineral resources and environmental protection by the state, inferior sandstones such as manufactured sand, sea sand, and recycled aggregates have been widely used. These changes in concrete raw materials have made the requirements for PCE more and more stringent. Therefore, it is particularly important to develop polycarboxylate superplasticizers with strong adaptability.

[0003] Patent CN111944101A reports a highly adaptable polycarboxylate superplasticizer prepared from unsaturated polyoxyethylene ether monomers and unsaturated phosphate monomers, which has extremely high adaptability to poor-quality sand and gravel aggregates, high mud content, manufactured sand and other environments, and exhibits excellent dispersion performance and slump retention ability.

[0004] Patent CN109679034A, based on a redox system, obtains a highly adaptable ester group-modified polycarboxylate superplasticizer through unsaturated polyethers, enols, amino acid mixtures, and unsaturated organic carboxylic acids, and performs well in construction projects with high requirements for cement adaptability.

[0005] Patent CN105236806A copolymerizes an unsaturated phosphoric acid monomer and a polyoxyethylene ether made from 2-phosphono-1,2,4-tricarboxylic acid butane, p-toluenesulfonic acid, and hydroquinone to prepare a phosphonic acid-based superplasticizer with good resistance to sulfate ions and mud.

[0006] Patent CN110204462A reports a methacrylic acid-6-dimethylaminohexyl ester intermediate prepared by the acyl chloride method. After the intermediate reacts with propanesultone to obtain an amphoteric ion monomer and is introduced into polycarboxylic acid, compared with ordinary anionic polycarboxylate superplasticizers, it has a higher water reduction rate and at the same time exhibits excellent dispersion performance and superior fluidity retention.

[0007] It can be found from the above research that the amphoteric polycarboxylate water reducer contains both cations and anions in its molecular structure, and can adsorb on the surfaces of hydration products with different charge properties such as C3A, C3S, and C2S in cement at the same time, thereby delaying cement hydration, improving the dispersion ability, and showing excellent dispersion retention. At the same time, phosphate groups have a strong adsorption effect on calcium ions in cement, can compete with sulfates for adsorption, and have good anti-sludge effect and cement adaptability. However, there are few reports on the performance synergistic effect of combining the two in one molecular structure. Summary of the Invention

[0008] The present invention aims to solve the problems of the sensitivity and adaptability of water reducers to various sand and gravel materials during the concrete construction process. By introducing phosphate groups and cations into the polymer molecular structure at the same time, a highly adaptable amphoteric phosphate-based water reducer with strong monomer structure adjustability, good water-reducing and slump-keeping properties, and excellent clay tolerance performance and its preparation method are provided.

[0009] The present invention provides a highly adaptable amphoteric phosphate-based water reducer, which is obtained by random copolymerization of an amphoteric phosphate monomer C having both an unsaturated quaternary ammonium salt cation and a phosphate group, an unsaturated carboxylic acid monomer D, and a polyoxyethylene ether macromonomer E in a molar ratio of (0.5-1):(2-6):1;

[0010] Among them, the unsaturated quaternary ammonium salt cation in the amphoteric phosphate monomer C is introduced by nucleophilic substitution of N-alkyl diethanolamine A and halogenated olefins, and the phosphate group is derived from the phosphate ester structure introduced by the hydroxyl group of the alkanolamine under the action of a phosphorylation reagent.

[0011] The general formula of the halogenated olefin is shown in (I):

[0012]

[0013] Wherein R1, R2, and R3 are independently selected from any one of H, CH3, CH2CH3, CH2CH2CH3, CH2OCH2CH3, OCH3, OCH2CH3, OCH2CH2CH3, and CH2CH2OCH3; X is selected from any one of F, Cl, Br, and I.

[0014] The structural general formula of the N-alkyl diethanolamine A is shown in (II):

[0015]

[0016] Wherein R4 is an alkyl group of C1-C6;

[0017] The N-alkyl diethanolamine A is selected from any one of N-methyldiethanolamine, N-ethyldiethanolamine, N-isopropyldiethanolamine, and N-n-butyldiethanolamine.

[0018] The phosphorylation reagent is selected from any one or more mixtures of phosphorus pentoxide (P2O5), polyphosphoric acid, phosphoric acid, metaphosphoric acid, sodium polyphosphate, potassium polyphosphate, sodium metaphosphate, potassium metaphosphate, sodium hexametaphosphate, pyrophosphoric acid, and sodium pyrophosphate.

[0019] The unsaturated carboxylic acid monomer D is selected from any one or more mixtures of acrylic acid, methacrylic acid, sodium acrylate, sodium methacrylate, maleic anhydride, and methoxyacrylic acid.

[0020] The chemical structure of the polyoxyethylene ether macromonomer E is represented by the following general formula (Ⅲ):

[0021]

[0022] In the formula, R5 is -H or -CH3; Y is -CH2-, -CH2OCH2CH2-, -CH2CH2-, -CH2CH2OCH2CH2-, -OCH2CH2-, -OCH2CH2OCH2CH2-, -OCH2CH2CH2CH2-, -C6H4-, or -C6H4CH2-, m + n = 10 to 100, and both m and n are positive integers.

[0023] The present invention provides a preparation method of the above-mentioned highly adaptable amphoteric phosphate-based water reducer, and the specific steps are as follows:

[0024] (1) Quaternization reaction: Add N-alkyl diethanolamine A, inhibitor, solvent, and catalyst into a device equipped with a reflux condenser. Slowly drop halogenated olefin at a certain temperature. After the dropping is completed, carry out a reflux reaction. After the reaction is completed, pour out the reaction solution, and obtain the quaternary ammonium salt cation intermediate B for use after purification;

[0025] The dropping temperature of the halogenated olefin is 60 - 150 °C, and the dropping time is controlled within 0.5 - 6 h; the reflux reaction time is 2 - 8 h;

[0026] (2) Phosphorylation: Weigh a certain amount of the quaternary ammonium salt cation intermediate B obtained in step (1). After strictly controlling the temperature, add the phosphorylation reagent. After the feeding is completed, raise the temperature to the set temperature, and carry out a phosphorylation reaction for 2 - 12 h. Add a measured amount of water, hydrolyze at a certain temperature, and then neutralize with sodium hydroxide to obtain an aqueous solution of the amphoteric phosphate monomer C;

[0027] The temperature when adding the phosphorylation reagent is controlled between 20 - 65 °C; the phosphorylation reagent is added in multiple times, with the same amount added each time, and the number of feeding times is not less than 3 times. After adding the phosphorylation reagent each time, react for 1 - 4 h;

[0028] The set temperature of the phosphorylation reaction is 50 - 130 °C;

[0029] The hydrolysis reaction temperature is 40 - 120 °C, and the hydrolysis time is 1 - 12 hours;

[0030] (3) Aqueous free radical polymerization: After mixing an appropriate amount of deionized water and polyoxyethylene ether macromonomer E evenly, simultaneously dropwise add an aqueous solution of the amphoteric phosphate monomer C described in step (2), an unsaturated carboxylic acid monomer D, a chain transfer agent, and a mixed solution of an initiator for polymerization reaction. After heat preservation for 1 - 6 h, add an appropriate amount of alkali to neutralize to pH = 6 - 7 to obtain the highly adaptable amphoteric phosphate-based water reducer;

[0031] The dropping temperature is 25 - 80 °C, the dropping time is 1 - 8 h, and the polymerization temperature and the heat preservation temperature are the same as the dropping temperature. *

[0032] In step (1), the reaction molar ratio of N-alkyl diethanolamine A to the haloolefin is 1:1.05 - 3. Note that the haloolefin is in excess during the reaction process and is added dropwise to the reaction system. To ensure the full reaction of N-alkyl ethanolamine and prevent the monomers obtained from the subsequent phosphorylation reaction from being ineffective, the excess haloolefin is removed in the subsequent purification step.

[0033] The catalyst described in step (1) is selected from any one of Na2CO3, K2CO3, pyridine, and triethylamine; the catalyst dosage is 1 - 5 times the molar amount of the raw material haloolefin, which absorbs the acid and weak basic substances generated during the reaction to avoid their influence on the reaction or reaction equilibrium;

[0034] The inhibitor described in step (1) is selected from any one or more mixtures of hydroquinone, p-methoxyphenol, 2,6-di-tert-butyl-p-cresol, 2-tert-butylhydroquinone, p-benzoquinone, and methylhydroquinone; the inhibitor dosage is 0.2% - 1.0% of the mass of the haloolefin;

[0035] The solvent described in step (1) is selected from lower alcohols, preferably any one of methanol, ethanol, propanol, and butanol; it is optimal to control the total reaction solute mass concentration at 30 - 70%;

[0036] The purification method described in step (1) is to remove most of the solvent by vacuum or atmospheric distillation and purify with anhydrous ether or acetone; specifically, add the reaction solution of step (1) after vacuum or distillation to anhydrous ether or acetone for washing 1 - 3 times, and collect the precipitate for vacuum drying.

[0037] In the reflux reaction described in step (1), the reaction time is 2 - 8 h. If the time is too short, the reaction is not sufficient; if the time is too long, the by-products increase and the efficiency decreases.

[0038] In step (2), the molar ratio of the alcohol hydroxyl group of the quaternary ammonium salt cation intermediate B to the phosphorylating reagent converted to phosphoric acid is 1:(1.01 - 3.5), preferably 1:(1.2 - 1.5), that is, to ensure that the phosphorylating reagent is sufficient or in excess. The essence of this reaction is that the phosphorylating reagent reacts with the hydroxyl group in the alkanolamine to obtain an unsaturated phosphate ester. If the phosphorylating reagent is a powder, it is easy to absorb water and agglomerate, and it needs to be added in small amounts and multiple times. The number of batches of its feeding should not be less than 3 times to prevent local violent heat release during the reaction, resulting in dehydration and carbonization of the hydroxyl group material, which is not conducive to the reaction; if the phosphorylating reagent is an aqueous agent, it is added in a dropwise manner. After the reaction is completed and hydrolyzed, the amphoteric phosphate monomer C is neutralized with sodium hydroxide to a pH value of 6.0 - 8.0, and water is added to adjust the solid content to 60%.

[0039] The set temperature of the phosphorylation reaction in step (2) is 50 - 130 °C. It should be noted that the preferred temperature range for using different phosphorylating reagents may be different. For example, when the phosphorylating reagent is phosphorus pentoxide, the molar ratio of the hydroxyl group in intermediate B to phosphorus pentoxide is 1∶1.2 - 1.5. After stirring and mixing evenly, it is preferably heated to 50 - 90 °C for reaction.

[0040] The by-product of the phosphorylation reaction in step (2) contains pyrophosphate bonds, and the pyrophosphate bonds will be broken after hydrolysis, thereby increasing the content of monoesters. The preferred amount of water used is 5% - 25% of the total mass of the reaction materials. Too much water should not be used to prevent gelation of the system. The hydrolysis reaction temperature is 40 - 120 °C, and the hydrolysis time is 1 - 12 hours. When the hydrolysis temperature is too low or the time is too short, the hydrolysis reaction is too slow. When the temperature is too high or the time is too long, the generated phosphate monoesters will decompose.

[0041] The polymerization method in step (3) is aqueous radical polymerization, and the polymerization concentration range is 20wt% - 80wt%.

[0042] The aqueous radical polymerization initiation system used in step (3) is a water-soluble inorganic peroxide initiator, a water-soluble redox initiation system or a water-soluble azo initiator; the water-soluble inorganic peroxides are selected from any one or more mixtures of potassium persulfate, ammonium persulfate, and sodium persulfate, and the water-soluble redox initiation system is selected from hydrogen peroxide - Rongalite, hydrogen peroxide - ascorbic acid, persulfate - sodium bisulfite, persulfate - Fe 2+mixed with any one or more of L-ascorbic acid; the water-soluble azo initiator is selected from any one or more of 2,2'-azobis(2-methylpropionamidine) dihydrochloride, 2,2'-azobis(2-isopropylimidazoline) hydrochloride, 2,2'-azobis(2-cyanovaleric acid), and 2,2'-azobis(2-isopropylimidazoline); the amount of the water-soluble inorganic peroxide initiator and the water-soluble azo initiator is 0.5-4 wt% of the total mass of the reaction monomers in step (3); in the redox initiator system, the amount of the reducing agent is 0.1-3 wt% of the total mass of the reaction monomers, the amount of the oxidizing agent is 0.1-5 wt% of the total mass of the reaction monomers, and the molar ratio of the oxidizing agent to the reducing agent is usually 2-8:1.

[0043] The chain transfer agent is a thiol chain transfer agent, selected from any one of mercaptoethanol, mercaptopropionic acid, mercaptoacetic acid, thioglycerol, thioglycolic acid, thiomalic acid, 2-mercaptoethanesulfonic acid, butanethiol, octanethiol, decanethiol, lauryl mercaptan, thiophenol, octyl thioglycolate, octyl 2-mercaptopropionate, octyl 3-mercaptopropionate, 2-ethylhexyl mercaptopropionate, and 2-mercaptoethyl octanoate; the amount used is 0.5-8 wt% of the total mass of the reaction monomers.

[0044] Specifically, the weight-average molecular weight range of a highly adaptable amphoteric phosphoric acid-based water reducer of the present invention is preferably controlled within 10,000-50,000.

[0045] The beneficial effects of the present invention are as follows:

[0046] (1) The cations and phosphate anions in the water reducer of the present invention can be simultaneously adsorbed on the hydration products with different charge properties of C3A or C3S and C2S.

[0047] (2) The strong adsorption performance of the phosphate group enables the amphoteric phosphoric acid-based water reducer of the present invention to have high adaptability in different cementitious materials.

[0048] (3) Due to the strong adsorption performance, the water reducer of the present invention has good tolerance to materials with a relatively high mud content.

[0049] (4) The highly adaptable amphoteric phosphoric acid-based water reducer of the present invention has good water-reducing and slump-retention properties. Specific embodiments

[0050] The specific embodiments of the present invention are described below to facilitate those skilled in the art of the present technology to understand the present invention. However, it should be clear that the present invention is not limited to the scope of the specific embodiments. The amounts used in each example and comparative example are in weight;

[0051] Synthesis Example 1:

[0052] (1) Add 50 parts of N-methyldiethanolamine, 0.35 parts of hydroquinone, 100 parts of methanol and 130 parts of Na2CO3 to a three-necked flask equipped with a reflux condenser, slowly add 75 parts of vinyl chloride at a temperature of 60°C, and control the addition time to be 6 hours. After the addition is completed, reflux reaction is carried out for 8 hours; after the reaction is completed, pour out the reaction solution, distill to remove the solvent, wash with anhydrous ether 3 times, and obtain the quaternary ammonium salt cationic intermediate B after purification;

[0053] (2) Weigh 50 parts of the reaction intermediate B, strictly control the temperature at 20°C, add 70 parts of sodium metaphosphate in three equal portions, and react for 4 hours after each addition of the phosphorylation reagent. After the addition is completed, raise the temperature to 50°C and phosphorylate for 12 hours. Add 6 parts of water and hydrolyze at 40°C for 12 hours to obtain the amphoteric phosphoric acid monomer C, which is neutralized with sodium hydroxide and set aside for use;

[0054] (3) 100 parts of deionized water, 50 parts of 4-hydroxybutyl vinyl polyoxyethylene ether (M w 1000), 0.3 parts of hydrogen peroxide (30%) were mixed uniformly, and a mixed solution of 22 parts of acrylic acid, 14 parts of phosphoric acid monomer C, 0.2 parts of ascorbic acid, and 0.5 parts of mercaptoethanol was added dropwise at a temperature of 25°C; the addition time was 1 hour, and after keeping warm for 6 hours, an appropriate amount of alkali was added to neutralize to pH 6-7 to obtain a highly adaptable amphoteric phosphate-based water reducer APE-1.

[0055] Synthesis Example 2:

[0056] (1) Add 50 parts of N-ethyldiethanolamine, 0.65 parts of 2-tert-butylhydroquinone, 300 parts of ethanol and 150 parts of K2CO3 to a three-necked flask equipped with a reflux condenser, slowly dropwise add 60 parts of 2-chloropropylene at a temperature of 90°C, and control the dropwise addition time to be within 4 hours. After the dropwise addition is completed, reflux reaction is carried out for 6 hours; after the reaction is completed, pour out the reaction solution, distill to remove the solvent, wash with anhydrous ether 3 times, and obtain the quaternary ammonium salt cationic intermediate B after purification;

[0057] (2) Weigh 50 parts of the reaction intermediate B, strictly control the temperature at 30°C, add 80 parts of sodium hexametaphosphate in three equal portions, and react for 4 hours after each addition of the phosphorylation reagent. After the addition is completed, raise the temperature to 60°C and phosphorylate for 10 hours. Add 10 parts of water and hydrolyze at 50°C for 6 hours to obtain the amphoteric phosphoric acid monomer C, which is neutralized with sodium hydroxide and set aside for use;

[0058] (3) 100 parts of deionized water, 50 parts of isopentyl polyoxyethylene ether (M w 4000) were mixed uniformly, and a mixed solution of 0.6 parts of ammonium persulfate, 5 parts of methacrylic acid, 5 parts of phosphoric acid monomer C, and 2.5 parts of mercaptopropionic acid was added dropwise at a temperature of 80°C; the addition time was 8 hours, and after keeping warm for 1 hour, an appropriate amount of alkali was added to neutralize to pH 6-7 to obtain a highly adaptable amphoteric phosphate-based water reducer APE-2.

[0059] Synthesis Example 3:

[0060] (1) Add 50 parts of N-isopropyldiethanolamine, 0.5 parts of methylhydroquinone, 500 parts of propanol and 130 parts of pyridine to a three-necked flask equipped with a reflux condenser, slowly dropwise add 50 parts of 2-bromopropylene at a temperature of 120°C, and control the dropwise addition time to be within 2 hours. After the dropwise addition is completed, reflux reaction is carried out for 4 hours; after the reaction is completed, pour out the reaction solution, distill to remove the solvent, wash with anhydrous acetone 3 times, and purify to obtain a quaternary ammonium salt cationic intermediate B;

[0061] (2) Weigh 50 parts of the reaction intermediate B, strictly control the temperature at 50°C, add 50 parts of phosphorus pentoxide in three equal portions, and react for 2 hours after each addition of the phosphorylation reagent. After the addition is completed, raise the temperature to 80°C and phosphorylate for 8 hours. Add 10 parts of water and hydrolyze at 70°C for 8 hours to obtain the amphoteric phosphoric acid monomer C, which is neutralized with sodium hydroxide and set aside for use;

[0062] (3) 100 parts of deionized water, 50 parts of methallyl polyoxyethylene ether (M w 4000), 3 parts of potassium persulfate were evenly mixed, and at the same time, 5 parts of maleic anhydride, 6 parts of phosphoric acid monomer C, 0.3 parts of sodium bisulfite, and 1 part of thioglycolic acid mixed solution were added dropwise at a temperature of 40°C; the addition time was 6 hours, and after keeping warm for 1 hour, an appropriate amount of alkali was added to neutralize to pH 6-7 to obtain highly adaptable amphoteric phosphate-based water reducer APE-3.

[0063] Synthesis Example 4:

[0064] (1) Add 50 parts of N-n-butyldiethanolamine, 0.4 parts of hydroquinone, 250 parts of butanol and 180 parts of triethylamine to a three-necked flask equipped with a reflux condenser, slowly dropwise add 45 parts of 1-chloro-2-butene at a temperature of 150°C, and control the dropwise addition time to be 0.5h. After the dropwise addition is completed, reflux reaction is carried out for 2h; after the reaction is completed, pour out the reaction solution, distill to remove the solvent, wash with anhydrous acetone 3 times, and obtain the quaternary ammonium salt cationic intermediate B after purification;

[0065] (2) Weigh 50 parts of the reaction intermediate B, strictly control the temperature at 60°C, add 65 parts of sodium pyrophosphate in three equal portions, and react for 1 hour after each addition of the phosphorylation reagent. After the addition is completed, raise the temperature to 90°C and phosphorylate for 6 hours. Add 15 parts of water and hydrolyze at 90°C for 5 hours to obtain the amphoteric phosphoric acid monomer C, which is neutralized with sodium hydroxide and set aside for use;

[0066] (3) 100 parts of deionized water, 50 parts of allyl polyoxyethylene ether (M w2000) were mixed uniformly, and 2 parts of potassium persulfate, 10 parts of methoxyacrylic acid, 15 parts of phosphoric acid monomer C, and 2 parts of 2-mercaptoethanesulfonic acid mixed solution were added dropwise at a temperature of 75°C; the addition time was 2 hours. After keeping warm for 3 hours, an appropriate amount of alkali was added to neutralize to pH 6-7 to obtain a highly adaptable amphoteric phosphate-based water reducer APE-4.

[0067] Synthesis Example 5:

[0068] (1) Add 50 parts of N-methyldiethanolamine, 0.35 parts of benzoquinone, 300 parts of methanol and 140 parts of Na2CO3 to a three-necked flask equipped with a reflux condenser, slowly add 60 parts of 1-iodo-2-butene at a temperature of 60°C, and control the addition time to be 6 hours. After the addition is completed, reflux reaction is carried out for 8 hours; after the reaction is completed, pour out the reaction solution, distill to remove the solvent, wash with anhydrous ether 3 times, and obtain the quaternary ammonium salt cationic intermediate B after purification;

[0069] (2) Weigh 50 parts of the reaction intermediate B, strictly control the temperature at 65°C, add 75 parts of sodium tripolyphosphate in three equal portions, and react for 1 hour after each addition of the phosphorylation reagent. After the addition is completed, raise the temperature to 130°C and phosphorylate for 2 hours. Add 20 parts of water and hydrolyze at 120°C for 1 hour to obtain the amphoteric phosphoric acid monomer C, which is neutralized with sodium hydroxide and set aside for use;

[0070] (3) 100 parts of deionized water, 50 parts of vinylphenol polyoxyethylene ether (M w 2000), 1 part of hydrogen peroxide (30%) was uniformly mixed, and a mixed solution of 10 parts of sodium acrylate, 12 parts of phosphoric acid monomer C, 3.5 parts of thiomalic acid, and 0.4 part of ascorbic acid was simultaneously added dropwise at a temperature of 25°C; the addition time was 2 hours, and after keeping warm for 6 hours, an appropriate amount of alkali was added to neutralize to pH 6-7 to obtain a highly adaptable amphoteric phosphate-based water reducer APE-5.

[0071] Synthesis Example 6:

[0072] (1) Add 50 parts of N-ethyldiethanolamine, 0.75 parts of 2-tert-butylhydroquinone, 180 parts of ethanol and 130 parts of K2CO3 to a three-necked flask equipped with a reflux condenser, slowly dropwise add 85 parts of 2-chloro-3-methoxypropylene at a temperature of 90°C, and control the dropwise addition time to be 4 hours. After the dropwise addition is completed, reflux reaction is carried out for 6 hours; after the reaction is completed, pour out the reaction solution, distill to remove the solvent, wash with anhydrous acetone 3 times, and obtain the quaternary ammonium salt cationic intermediate B after purification;

[0073] (2) Weigh 50 parts of the reaction intermediate B, strictly control the temperature at 50°C, add 50 parts of polyphosphoric acid in three equal portions, and react for 3 hours after each addition of the phosphorylation reagent. After the addition is completed, raise the temperature to 120°C and phosphorylate for 3 hours. Add 25 parts of water and hydrolyze at 80°C for 8 hours to obtain the amphoteric phosphoric acid monomer C, which is neutralized with sodium hydroxide and set aside for use;

[0074] (3) 100 parts of deionized water, 50 parts of methyl allyl polyoxyethylene ether (M w 2000) were mixed uniformly, and a mixed solution of 8 parts of sodium methacrylate, 13 parts of phosphoric acid monomer C, 2 parts of butanethiol, and 1.5 parts of azobisisobutylamidine hydrochloride was added dropwise at a temperature of 50°C; the addition time was 3 hours, and after keeping warm for 2 hours, an appropriate amount of alkali was added to neutralize to pH 6-7 to obtain a highly adaptable amphoteric phosphate-based water reducer APE-6.

[0075] Synthesis Example 7:

[0076] (1) Add 50 parts of N-isopropyldiethanolamine, 0.25 parts of methylhydroquinone, 110 parts of propanol and 150 parts of pyridine to a three-necked flask equipped with a reflux condenser, slowly dropwise add 60 parts of 1-bromo-3-ethoxypropylene at a temperature of 100° C., and control the dropwise addition time to 2 hours. After the dropwise addition is completed, reflux reaction is carried out for 4 hours; after the reaction is completed, pour out the reaction solution, distill to remove the solvent, wash with anhydrous ether 3 times, and obtain the quaternary ammonium salt cationic intermediate B after purification;

[0077] (2) Weigh 50 parts of the reaction intermediate B, strictly control the temperature at 55°C, add 50 parts of phosphoric acid in three equal portions, and react for 3 hours after each addition of the phosphorylation reagent. After the addition is completed, raise the temperature to 100°C and phosphorylate for 4 hours. Add 8 parts of water and hydrolyze at 40°C for 12 hours to obtain the amphoteric phosphoric acid monomer C, which is neutralized with sodium hydroxide and set aside for use;

[0078] (3) 100 parts of deionized water, 50 parts of allyl polyoxyethylene ether (M w 2400), 5 parts of hydrogen peroxide (30%) were mixed evenly, and 5 parts of acrylic acid, 15 parts of amphoteric phosphoric acid monomer C, 1.5 parts of octanethiol, and 1 part of Rongalite mixed solution were added dropwise at 40°C; the addition time was 2 hours. After keeping warm for 3 hours, an appropriate amount of alkali was added to neutralize the mixture to pH 6-7 to obtain a highly adaptable amphoteric phosphoric acid-based water reducer APE-7.

[0079] Synthesis Example 8:

[0080] (1) Add 50 parts of N-n-butyldiethanolamine, 0.4 parts of benzoquinone, 200 parts of butanol and 100 parts of triethylamine to a three-necked flask equipped with a reflux condenser, slowly add 70 parts of 2-fluoro-2-butene at a temperature of 60°C, and control the addition time to be 0.5h. After the addition is completed, reflux reaction is carried out for 2h; after the reaction is completed, pour out the reaction solution, distill to remove the solvent, wash with anhydrous ether 3 times, and obtain the quaternary ammonium salt cationic intermediate B after purification;

[0081] (2) Weigh 50 portions of reaction intermediate B, strictly control the temperature at 50 °C, and add 40 portions of phosphorus pentoxide in three equal portions. After adding the phosphorylation reagent each time, react for 4 h. After the feeding is completed, raise the temperature to 70 °C and carry out the phosphorylation reaction for 6 h. Add 5 portions of water and hydrolyze at 50 °C for 6 h to obtain the amphoteric phosphate monomer C. After neutralization with sodium hydroxide, it is ready for use;

[0082] (3) Mix 100 portions of deionized water, 50 portions of isopentenyl polyoxyethylene ether (M w 1000), and 3 portions of hydrogen peroxide (30%) evenly. At a temperature of 50 °C, simultaneously drip a mixed solution of 21 portions of acrylic acid, 17 portions of amphoteric phosphate monomer C, 0.6 portion of ascorbic acid, and 0.5 portion of mercaptoethanol; the dripping time is 2 h. After keeping warm for 2 h, add an appropriate amount of alkali to neutralize to pH 6 - 7 to obtain the highly adaptable amphoteric phosphate-based water reducer APE-8.

[0083] Comparative Example 1:

[0084] (1) Add 50 portions of N-methyldiethanolamine, 0.35 portion of hydroquinone, 100 portions of methanol, and 130 portions of Na2CO3 into a three-necked flask equipped with a reflux condenser. At a temperature of 60 °C, slowly drip 75 portions of vinyl chloride, and control the dripping time within 6 h. After the dripping is completed, carry out the reflux reaction for 8 h; after the reaction is completed, pour out the reaction solution, distill off the solvent, wash with anhydrous ether 3 times, and obtain the quaternary ammonium salt cation intermediate B after purification;

[0085] (2) Mix 100 portions of deionized water, 50 portions of 4-hydroxybutyl vinyl polyoxyethylene ether (M w 1000), and 0.3 portion of hydrogen peroxide (30%) evenly. At a temperature of 25 °C, simultaneously drip a mixed solution of 22 portions of acrylic acid, 3.6 portions of quaternary ammonium salt cation intermediate B, and 0.2 portion of ascorbic acid; the dripping time is 1 h. After keeping warm for 6 h, add an appropriate amount of alkali to neutralize to pH 6 - 7 to obtain the water reducer REF-1.

[0086] Comparative Example 2:

[0087] Mix 100 portions of deionized water, 50 portions of 4-hydroxybutyl vinyl polyoxyethylene ether (M w 1000), and 0.3 portion of hydrogen peroxide (30%) evenly. At a temperature of 25 °C, simultaneously drip a mixed solution of 22 portions of acrylic acid and 0.2 portion of ascorbic acid; the dripping time is 1 h. After keeping warm for 6 h, add an appropriate amount of alkali to neutralize to pH 6 - 7 to obtain the water reducer REF-2.

[0088] Comparative Example 3:

[0089] REF-3 is a -HP phosphate-based water reducer purchased from Nanjing Bote New Materials Co., Ltd.

[0090] Application Example 1

[0091] The fluidity of neat cement paste was tested according to GB / T 8077—2012 "Test Methods for the Homogeneity of Concrete Admixtures". The water-cement ratio was 0.29 and the dosage was 0.12%.

[0092] Table 1 Fluidity of neat cement paste in different cements (unit: mm)

[0093] Sample Onoda Conch Heklin Yadong APE-1 240 250 235 239 APE-2 235 248 230 245 APE-3 242 248 239 240 APE-4 245 252 238 239 APE-5 250 240 229 252 APE-6 240 238 230 238 APE-7 239 245 232 241 APE-8 239 239 225 230 REF-1 250 280 190 205 REF-2 232 264 No fluidity 170 REF-3 210 222 170 195

[0094] As can be seen from Table 1, through the variation law of the initial fluidity of each sample in different cements, it can be seen that the highly adaptable amphoteric phosphate-based water reducer provided by the present invention shows relatively stable fluidity performance for Onoda, Conch, Heklin, and Yadong cements. Especially in Heklin cement, it still has good fluidity; while compared with ordinary water reducers, it shows different initial water-reducing abilities and a large jump. In summary, Examples 1 to 8 have good cement adaptability.

[0095] Application Example 2

[0096] Heklin cement was selected, the solid content of the water reducer was 0.14%, and the water-cement ratio was 0.29. Different masses of sodium sulfate were added to replace the cement, and the changes in the fluidity of neat cement paste under different sulfate contents were investigated. The results are shown in Table 2.

[0097] Table 2 Results of neat cement paste under different sulfate contents (unit: mm)

[0098]

[0099] As can be seen from the results in Table 2, the highly adaptable amphoteric phosphate-based water reducer provided by the present invention shows relatively stable fluidity of neat cement paste at different sulfate contents. With the increase in the amount of sulfate incorporated, its initial dispersion and dispersion retention performance have obvious advantages compared with the comparative examples. Obviously, REF-1, REF-2, and REF-3 are more affected by the sulfate ion concentration, which benefits from the dual adsorption effect provided by the phosphate group and the cationic group and has more advantages in the competitive adsorption with sulfate ions.

[0100] Application Example 3

[0101] Mortar containing clay

[0102] 700 g of Heklin cement, 1350 g of IOS standard sand, 240 g of water were selected, and the solid content of the polycarboxylate water reducer was 0.12%. Montmorillonite was used to replace different masses of cement, and the changes in the fluidity of neat cement paste under different clay contents were investigated. The results are shown in Table 3.

[0103] Table 3 Properties of mortar in muddy environment (unit: mm)

[0104]

[0105]

[0106] From the above mortar results shown in Table 3, after introducing zwitterionic monomers, whether in the environment with or without mud, the water reduction and slump retention of APE-1 to 8 have been significantly improved. As the mud content increases from 1% to 2%, the fluidity of the comparative sample decreases significantly and the fluidity loss accelerates. However, although the change range of the examples provided by the present invention is relatively small, it shows obvious mud tolerance; comparing the samples of APE1 to 8 and REF-1 after phosphorylation, the tolerance to soil of the simple cation is significantly improved, showing a synergistic effect.

[0107] Application Example 4

[0108] Machine-made sand concrete

[0109] The powder content of the machine-made sand used is 6.5%, the mud content is 0.3%, and the void ratio is 41%. The water reducers prepared in the above Examples 1-2 were used to measure the concrete slump flow according to GB / T8077-2012 "Test Methods for the Homogeneity of Concrete Admixtures" respectively. The test temperature was 20±2°C, and the results are shown in the table.

[0110] Table 4 Concrete Mix Ratio (unit: kg)

[0111] Cement Fly ash Machine-made sand Crushed stone Water 340 100 960 840 175

[0112] Table 5 Concrete Results

[0113]

[0114]

[0115] From the results of the concrete containing machine-made sand shown in Table 5, the water reduction and slump retention performance of APE-1 and APE-2 provided by the present invention are relatively excellent. The initial fluidity of the concrete is better than that of the comparative sample. At the same time, it is found that its air content is slightly higher and the workability of the concrete is better; and it has no obvious influence on the later strength. Thus, it can be seen that the highly adaptable amphoteric phosphate-based water reducer provided by the present invention has good compatibility with machine-made sand.

Claims

1. A highly adaptable amphoteric phosphoric acid-based water reducer, characterized in that, It is obtained by random copolymerization of an amphoteric phosphate monomer C having both an unsaturated quaternary ammonium salt cation and a phosphate group, an unsaturated carboxylic acid monomer D, and a polyoxyethylene ether macromonomer E in a molar ratio of (0.5 - 1):(2 - 6):1; The unsaturated quaternary ammonium salt cation in the amphoteric phosphate monomer C is introduced by nucleophilic substitution of N-alkyl diethanolamine A with a halogenated olefin, and the phosphate group is derived from a phosphate ester structure introduced by the hydroxyl group of the alkanolamine under the action of a phosphorylation reagent.

2. The high-adaptability amphoteric phosphate-based water reducer according to claim 1, wherein The general formula of the halogenated olefin is shown as (I): wherein R1, R2, and R3 are independently selected from any one of H, CH3, CH2CH3, CH2CH2CH3, CH2OCH2CH3, OCH3, OCH2CH3, OCH2CH2CH3, CH2CH2OCH3; X is selected from any one of F, Cl, Br, I; The structural general formula of the N-alkyl diethanolamine A is shown as (II): wherein R4 is an alkyl group of C1 - C6; The phosphorylation reagent is selected from any one or more mixtures of phosphorus pentoxide (P2O5), polyphosphoric acid, phosphoric acid, metaphosphoric acid, sodium polyphosphate, potassium polyphosphate, sodium metaphosphate, potassium metaphosphate, sodium hexametaphosphate, pyrophosphoric acid, sodium pyrophosphate.

3. The high-adaptability amphoteric phosphate-based water reducer according to claim 2, characterized in that, The N-alkyl diethanolamine A is selected from any one of N-methyldiethanolamine, N-ethyldiethanolamine, N-isopropyldiethanolamine, N-n-butyldiethanolamine.

4. A highly adaptable amphoteric phosphate-based water reducing agent according to claim 1, characterized in that, The unsaturated carboxylic acid monomer D is selected from any one or more mixtures of acrylic acid, methacrylic acid, sodium acrylate, sodium methacrylate, maleic anhydride, methoxyacrylic acid; The chemical structure of the polyoxyethylene ether macromonomer E is represented by the following general formula (III): In the formula, R5 is -H or -CH3; Y is -CH2-, -CH2OCH2CH2-, -CH2CH2-, -CH2CH2OCH2CH2-, -OCH2CH2-, -OCH2CH2OCH2CH2-, -OCH2CH2CH2CH2-, -C6H4- or -C6H4CH2-, m + n = 10 - 100, and both m and n are positive integers.

5. The high-adaptability amphoteric phosphate-based water reducer according to claim 1, characterized in that, The weight-average molecular weight range of the highly adaptable amphoteric phosphate-based water reducer is controlled at 10000 - 50000.

6. The preparation method of a highly adaptable amphoteric phosphate-based water reducer according to any one of claims 1 to 5, characterized in that, The specific steps are as follows: (1) Quaternization reaction: Add N-alkyl diethanolamine A, a polymerization inhibitor, a solvent, and a catalyst into a device equipped with a reflux condenser, slowly dropwise add a halogenated olefin at a certain temperature, after the dropping is completed, carry out a reflux reaction, pour out the reaction solution after the reaction is completed, and obtain a quaternary ammonium salt cation intermediate B for use after purification; (2) Phosphorylation: Weigh a certain amount of the quaternary ammonium salt cation intermediate B obtained in step (1), strictly control the temperature, add a phosphorylation reagent, after the feeding is completed, raise the temperature to a set temperature, carry out a phosphorylation reaction for 2 - 12 h, add a measured amount of water, hydrolyze at a certain temperature, and then neutralize with sodium hydroxide to obtain an aqueous solution of the amphoteric phosphate monomer C; (3) Aqueous free radical polymerization: After mixing an appropriate amount of deionized water and polyoxyethylene ether macromonomer E evenly, simultaneously dropwise add the mixed solution of the aqueous solution of amphoteric phosphate monomer C, unsaturated carboxylic acid monomer D, chain transfer agent and initiator described in step (2) for polymerization reaction. After heat preservation for 1 - 6 h, add an appropriate amount of base to neutralize to pH = 6 - 7 to obtain the high-adaptability amphoteric phosphate-based water reducer.

7. The preparation method of a highly adaptable amphoteric phosphate-based water reducer according to claim 6, characterized in that, In step (1), the reaction molar ratio of N-alkyl diethanolamine A to haloolefin is 1:1.05 - 3; In step (2), the molar ratio of the alcoholic hydroxyl group of quaternary ammonium salt cation intermediate B to the phosphorylating agent converted to phosphoric acid is 1:(1.01 - 3.5); In step (3), the polymerization method is aqueous free radical polymerization, and the polymerization concentration range is 20 wt% - 80 wt%.

8. The preparation method of a highly adaptable amphoteric phosphate-based water reducing agent according to claim 7, characterized in that, In step (1), the dropping temperature of the haloolefin is 60 - 150 °C, and the dropping time is controlled within 0.5 - 6 h; the reflux reaction time is 2 - 8 h; In step (2), the temperature when adding the phosphorylating agent is controlled between 20 - 65 °C; the set temperature of the phosphorylation reaction is 50 - 130 °C, the hydrolysis reaction temperature is 40 - 120 °C, and the hydrolysis time is 1 - 12 hours; In step (3), the dropping temperature is 25 - 80 °C, the dropping time is 1 - 8 h, and the polymerization temperature and the heat preservation temperature are the same as the dropping temperature.

9. The preparation method of a highly adaptable amphoteric phosphate-based water reducer according to claim 7 or 8, characterized in that, In step (1), the catalyst is 1 - 5 times the molar amount of the raw material haloolefin, and the dosage of the inhibitor is 0.2% - 1.0% of the mass of the haloolefin; the solvent is selected from lower alcohols, and the total reaction solute mass concentration is controlled at 30 - 70%.

10. The preparation method of a highly adaptable amphoteric phosphate-based water reducer according to claim 7 or 8, characterized in that, In step (2), the measured water dosage is 5% - 25% of the total mass of the reaction materials; the molar ratio of the alcoholic hydroxyl group of quaternary ammonium salt cation intermediate B to the phosphorylating agent converted to phosphoric acid is 1:(1.2 - 1.5).

11. The preparation method of a highly adaptable amphoteric phosphate-based water reducing agent according to claim 7 or 8, characterized in that, In step (3), the aqueous free radical polymerization initiation system used is a water-soluble inorganic peroxide initiator, a water-soluble redox initiation system or a water-soluble azo initiator; the dosages of the water-soluble inorganic peroxide initiator and the water-soluble azo initiator are 0.5 - 4 wt% of the total mass of the reaction monomers in step (3); in the redox initiation system, the dosage of the reducing agent is 0.1 - 3 wt% of the total mass of the reaction monomers, the dosage of the oxidizing agent is 0.1 - 5 wt% of the total mass of the reaction monomers, and the molar ratio of the oxidizing agent to the reducing agent is 2 - 8:1; In step (3), the chain transfer agent is a thiol chain transfer agent, and the dosage is 0.5 - 8 wt% of the total mass of the reaction monomers.

12. The preparation method of a highly adaptable amphoteric phosphate-based water reducing agent according to claim 9, characterized in that, In step (1), the catalyst is selected from any one of Na2CO3, K2CO3, pyridine, and triethylamine; In step (1), the inhibitor is selected from any one or more mixtures of hydroquinone, p-methoxyphenol, 2,6-di-tert-butyl-p-cresol, 2-tert-butylhydroquinone, p-benzoquinone, and methylhydroquinone; In step (1), the solvent is selected from any one of methanol, ethanol, propanol, and butanol.

13. The preparation method of a highly adaptable amphoteric phosphate-based water reducing agent according to claim 9, characterized in that, In step (1), the purification method is to remove most of the solvent by vacuum or atmospheric distillation and purify with anhydrous ether or acetone.

14. The preparation method of a highly adaptable amphoteric phosphate-based water reducing agent according to claim 10, characterized in that, In step (2), when the phosphorylation reagent is in powder form, it is added multiple times with the same amount each time, and the number of feeding times is not less than 3 times. After adding the phosphorylation reagent each time, the reaction proceeds for 1 to 4 hours; when the phosphorylation reagent is in aqueous solution form, it is added dropwise. After the reaction is completed and hydrolysis occurs in step (2), the aqueous solution of the amphoteric phosphate monomer C is neutralized to a pH value of 6.0 to 8.0 with sodium hydroxide and the solid content is adjusted to 60% by adding water.

15. The preparation method of a highly adaptable amphoteric phosphate-based water reducing agent according to claim 11, characterized in that, The water-soluble inorganic peroxides used in step (3) are selected from any one or more of potassium persulfate, ammonium persulfate, and sodium persulfate, and the water-soluble redox initiation system is selected from any one or more of hydrogen peroxide-rongalite, hydrogen peroxide-ascorbic acid, persulfate-sodium bisulfite, and persulfate-Fe 2+ -ascorbic acid; the water-soluble azo initiator is selected from any one or more of 2,2'-azobis(2-methylpropionamidine) dihydrochloride, 2,2'-azobis(2-isopropylimidazoline) dihydrochloride, 2,2'-azobis(2-cyanovaleric acid), and 2,2'-azobis(2-isopropylimidazoline); The chain transfer agent is selected from any one of mercaptoethanol, mercaptopropionic acid, mercaptoacetic acid, thioglycerol, thioglycolic acid, thiomalic acid, 2-mercaptoethanesulfonic acid, butanethiol, octanethiol, decanethiol, lauryl mercaptan, thiophenol, octyl thioglycolate, octyl 2-mercaptopropionate, octyl 3-mercaptopropionate, 2-ethylhexyl mercaptopropionate, 2-mercaptoethyl octanoate.

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