A highly adaptable polycondensation carboxylate water reducer, preparation method and application thereof

Abstract

The present invention belongs to the technical field of concrete admixtures, and specifically relates to a highly adaptable polycondensation carboxylate water reducer, a preparation method and its application. The highly adaptable polycondensation carboxylate water reducer is formed by polycondensation of monomer A, monomer B and monomer C; the monomer A is a phenyl isocyanate compound with a carboxyl group, formed by the reaction of a phenyl isocyanate monomer and a carboxyl monomer with a hydroxyl or amine group; the monomer B is a phenyl isocyanate compound with a long-chain polyether, formed by the reaction of a phenyl isocyanate monomer and a methoxy polyoxyethylene ether monomer; the monomer C is an aldehyde monomer selected from formaldehyde, acetaldehyde, glyoxylic acid and benzaldehyde. The water reducer introduces a benzene ring structure into the main chain, so that it has better air entraining performance, and can improve the workability, workability and adaptability of concrete to cement compared with traditional polycarboxylate water reducers.

Description

Technical Field

[0001] The invention belongs to the technical field of concrete admixtures, and in particular relates to a highly adaptable polycondensation carboxylate water reducing agent, a preparation method and application thereof. Background Art

[0002] Concrete is the largest building material in the world. Concrete admixture is one of the essential components of modern concrete and an important method and technology for concrete modification. Water reducer is the most important component. After decades of development, water reducer has evolved from the earliest ordinary water reducer of lignin sulfonate to high-efficiency water reducers represented by sulfonated melamine formaldehyde and naphthalene series, and then to the widely used high-performance polycarboxylic acid series water reducer with better performance.

[0003] Aggregates account for about 60%-70% of the volume of concrete, and the amount of sand and gravel consumed each year is very large. High-quality sand and gravel aggregates are becoming increasingly scarce, and the deterioration trend of sand and gravel aggregates is becoming more and more obvious. Soil is a common harmful component in sand and gravel. Excessive clay mineral content in sand and gravel will lead to a decrease in the strength and durability of concrete, and will significantly increase the shrinkage of concrete. Not only that, too much clay minerals will significantly reduce the dispersion performance of water reducers. Polycarboxylate water reducer is a new type of concrete admixture with a special structure. It has a series of outstanding advantages such as high water reduction rate, high slump retention capacity, low dosage, low alkali content, low shrinkage and environmental friendliness. However, the adaptability between polycarboxylate water reducer and concrete raw materials has always been an important reason restricting the widespread use of polycarboxylate water reducer.

[0004] In order to solve the compatibility problem of polycarboxylic acid water reducers with cement types and sand and gravel aggregates, engineering technicians and researchers conducted modification research at the level of water reducer molecular structure based on research theory.

[0005] Patent CN112745464A introduces phosphate into polycarboxylate water reducer to synthesize a highly adaptable and early-strength polycarboxylate water reducer. The highly adaptable and early-strength polycarboxylate water reducer containing phosphate is copolymerized by 90-110 parts of unsaturated polyether macromonomer, 10-20 parts of unsaturated carboxylic acid and 1-6 parts of phosphoric acid-containing acrylamide free radicals. Among them, the polyacrylic acid derivative and polyether side chain on the water reducer molecular chain provide dispersibility. On the one hand, the phosphate-containing polyacrylamide improves the adaptability of the water reducer due to the presence of the phosphate group. On the other hand, the amide group not only balances the slow setting effect of the phosphate group, but also improves the early strength effect of the product, so that it has good adaptability and early strength effect when mixing different types of cement and high-mud aggregate concrete. However, phosphoric acid acrylamide is difficult to synthesize with current technology and is difficult to apply industrially.

[0006] Patent CN112979865A discloses the preparation of an anti-mud polycarboxylate water reducer, and its preparation process includes methacryloyloxyethyl trimethylammonium chloride, acrylic acid, hydrogen peroxide, ascorbic acid, a chain transfer agent, and the balance is water. The preparation process of the present invention is simple, the reaction is carried out at room temperature, the entire production process has a short reaction time, low energy consumption, low cost, high safety factor, and is easy to industrialize. The anti-mud polycarboxylate water reducer produced by this inventive method has a significant effect on the ground materials with high mud content in the country, with high water reduction rate, low parameters, and good collapse resistance. It can make up for the shortcomings of poor adaptability of conventional polycarboxylate water reducers in the current market when encountering ground materials with high mud content. This water reducer does not contain a polyether structure, cannot provide sufficient steric hindrance, and the water reducer effect is insufficient.

[0007] The above-mentioned polycarboxylic acid water-reducing agents are prepared by adding other unsaturated monomers and copolymerizing them by free radical polymerization. Summary of the invention

[0008] In order to solve the compatibility problem of polycarboxylate water reducers in the prior art with cement types and sand and gravel aggregates mentioned in the background technology, the present invention provides a highly adaptable polycondensation carboxylate water reducer, a preparation method and an application thereof. The water reducer introduces a benzene ring structure into the main chain to make it have better air entraining performance. Compared with traditional polycarboxylate water reducers, it can improve the workability, workability and adaptability of concrete to cement.

[0009] To solve the above problems, the present invention provides the following technical solutions:

[0010] A highly adaptable polycondensation carboxylate water reducer, which is prepared by polycondensation of monomer A, monomer B and monomer C.

[0011] The monomer A is a phenyl isocyanate compound with a carboxyl group, which is formed by the reaction of a phenyl isocyanate monomer and a carboxyl monomer with a hydroxyl group or an amine group; the isocyanate monomer is selected from phenyl isocyanate, 4-methylphenyl isocyanate, 3,5-dimethylphenyl isocyanate, diphenylmethane diisocyanate, and toluene diisocyanate; the carboxyl monomer is selected from hydroxycarboxylic acids or amino acids such as glycolic acid, citric acid, glycine, and alanine.

[0012] The monomer B is a phenyl isocyanate compound with a long-chain polyether, which is formed by the reaction of a phenyl isocyanate monomer and a methoxy polyoxyethylene ether monomer; the isocyanate monomer is selected from phenyl isocyanate, 4-methylphenyl isocyanate, 3,5-dimethylphenyl isocyanate, diphenylmethane diisocyanate, and toluene diisocyanate; the mass fraction of the methoxy polyoxyethylene ether monomer is Mn=1000-8000.

[0013] The monomer C is an aldehyde monomer selected from formaldehyde, acetaldehyde, glyoxylic acid, and benzaldehyde.

[0014] The molar ratio of the monomer A, monomer B and monomer C is: monomer A / monomer B=2-6, monomer C / (monomer A+monomer B)=1-1.3.

[0015] The weight average molecular weight of the highly adaptable polycondensation carboxylate water reducer is 10,000-30,000.

[0016] The present invention also provides a method for preparing a highly adaptable polycondensation carboxylate water reducer, which specifically comprises the following steps:

[0017] (1) Preparation of Monomer A: Add a non-protonic solvent, phenyl isocyanate monomer and carboxyl monomer into a dry flask, react at 60° C.-120° C. for 2-8 hours to obtain a polycondensable carboxyl monomer, i.e., Monomer A.

[0018] (2) Preparation of Monomer B: Add phenyl isocyanate monomer and methoxy polyoxyethylene ether monomer into a dry flask and react at 80-130° C. for 2-8 hours to obtain a polycondensable polyether macromonomer, i.e., Monomer B.

[0019] (3) Synthesis of highly adaptable polycondensation carboxylate water reducer: Add the monomers obtained in step 1 and step 2 into a flask, add a protonic acid catalyst and monomer C, and react at 100-150° C. for 4-10 hours to obtain a polycondensation carboxylate water reducer.

[0020] In the step (1), the aprotic solvent is one of N,N-dimethylformamide and dimethyl sulfoxide, and the solvent content is 30%-70% of the total reactant mass.

[0021] In the step (1), the molar ratio of the phenyl isocyanate monomer to the carboxyl monomer is 1:1-1:1.2.

[0022] In the step (2), the molar ratio of the methoxy polyoxyethylene ether monomer to the phenyl isocyanate monomer is 1:1-1:1.1.

[0023] In the step (3), the protonic acid catalyst is one of sulfuric acid, phosphoric acid and p-toluenesulfonic acid, and the content of the protonic acid catalyst accounts for 3%-15% of the total mass of the reactants.

[0024] The present invention also provides a highly adaptable polycondensation carboxylate water reducer as a cement-based material dispersant; the polycondensation carboxylate water reducer obtained by the present invention has good adaptability to cement and admixtures as a cement-based material dispersant, has good air entrainment performance, good working performance and workability, and its dosage (solid dosage) is 1‰-5‰ of the mass of the cementitious material when used, and the specific dosage is determined according to the actual engineering needs. However, when the dosage is less than 1‰, its dispersibility is not good and cannot meet the engineering requirements. When the dosage exceeds 5‰, the cost performance is not high, and excessive dosage will also cause segregation and bleeding.

[0025] Compared with the prior art, the present invention has the following beneficial effects:

[0026] The present invention introduces a phenyl isocyanate structure. The isocyanate group is a highly active group that can react with polyethers and carboxyl monomers with hydroxyl or amino groups, and the monomers after the reaction can undergo a condensation reaction with aldehydes. Through the condensation reaction, a main chain skeleton can be obtained that is a non-polar long chain of benzene rings. Compared with conventional polycarboxylate water reducers, the main chain contains a benzene ring structure, has better air entrainment performance, and the obtained water reducer is insensitive to cement-based admixture components, has strong adaptability to cement and sand and gravel aggregates, and has strong concrete workability and workability.

[0027] The preparation method provided by the invention has simple reaction conditions and is easy to operate, and the obtained water reducer has stable structure and performance; the polycondensation type carboxylate water reducer can be used alone or in combination with other water reducers on the market. DETAILED DESCRIPTION

[0028] In order to better understand the present invention, the content of the present invention is further explained below in conjunction with the examples, but the content of the present invention is not limited to the following examples. Any equivalent changes or modifications made according to the spirit of the present invention should be included in the protection scope of the present invention.

[0029] In the examples of the present invention, the molecular weight of the condensate was determined using a Wyatt Technology Corporation gel permeation chromatograph (GPC). The experimental conditions were as follows:

[0030] Gel column: Shodex SB806+803 two chromatographic columns connected in series;

[0031] Washing solution: 0.1M NaNO3 solution;

[0032] Mobile phase speed: 1.0 mL / min;

[0033] Injection: 20uL 0.5% aqueous solution;

[0034] Detector: Shodex RI-71 differential refractometer;

[0035] Standard: polyethylene glycol GPC standard (Sigma-Aldrich, molecular weight 1010000, 478000, 263000, 118000, 44700, 18600, 6690, 1960, 826, 232).

[0036] The cement used is Onoda 42.5RP‖, Helin 42.5RPO, Conch 42.5RPO, benchmark cement PI42.5, and Zhongshan brand PO42.5 cement. The sand is medium sand with a fineness modulus Mx=2.6, and the stone particle size is 5-20mm continuously graded crushed stone. The concrete slump, water reduction rate, and air content tests are carried out in accordance with the relevant provisions of the national standard GB / T8076-2008 "Concrete Admixtures", and the additive dosage is the solid dosage.

[0037] Example 1

[0038] Preparation of monomer A: In a 250 mL three-necked flask, 50 g of dimethyl sulfoxide and 19.2 g of citric acid were added, heated to 90° C., 11.9 g of phenyl isocyanate was added dropwise, and reacted for 3 h to obtain a polycondensable carboxyl monomer.

[0039] Preparation of Monomer B: 100 g of methoxy polyoxyethylene ether with a molecular weight of Mn=2000 was added to a 250 mL flask, the temperature was raised to 100° C., 5.95 g of phenyl isocyanate was added dropwise, and the mixture was reacted for 4 h to obtain a polycondensable polyether monomer.

[0040] Preparation of water reducer: Pour the condensable carboxyl monomer and the condensable polyether monomer into a 500 mL flask, add 6 g of sulfuric acid, heat to 120°C, drop 14.59 g of formaldehyde with a concentration of 37%, react for 6 hours, cool, add water and NaOH to adjust the pH to 5, and obtain water reducer S1 with a molecular weight of Mn=16558.

[0041] Example 2

[0042] Preparation of monomer A: In a 250 mL three-necked flask, add 70 g of dimethyl sulfoxide and 33.44 g of glycolic acid, heat to 100° C., add dropwise 58.8 g of benzene 3,5-dimethylphenyl isocyanate, and react for 4 hours to obtain a polycondensable carboxyl monomer.

[0043] Preparation of monomer B: 100 g of methoxy polyoxyethylene ether with a molecular weight of Mn=1000 was added to a 250 mL flask, the temperature was raised to 80° C., 16.17 g of 3,5-dimethylphenyl isocyanate was added dropwise, and the reaction was carried out for 8 h to obtain a polycondensable polyether monomer.

[0044] Preparation of water reducer: Pour condensable carboxyl monomer and condensable polyether monomer into a 500 mL flask, add 20 g of phosphoric acid, heat to 140° C., drop 22.44 g of acetaldehyde, react for 4 h, cool, add water and NaOH to adjust the pH to 5, and obtain water reducer S2 with a molecular weight of Mn=14684.

[0045] Example 3

[0046] Preparation of monomer A: In a 250 mL three-necked flask, add 60 g of N,N-dimethylformamide and 45 g of glycine, heat to 120° C., add dropwise 59.5 g of phenyl isocyanate, and react for 2 h to obtain a polycondensable carboxyl monomer.

[0047] Preparation of Monomer B: 300 g of methoxy polyoxyethylene ether with a molecular weight of Mn=3000 was added to a 500 mL flask, the temperature was raised to 130° C., 13.09 g of phenyl isocyanate was added dropwise, and the mixture was reacted for 2 h to obtain a polycondensable polyether monomer.

[0048] Preparation of water reducer: Pour the condensable carboxyl monomer and the condensable polyether monomer into a 500 mL flask, add 57 g of p-toluenesulfonic acid, heat to 150°C, add 84.06 g of benzaldehyde dropwise, react for 5 hours, cool, add water and NaOH to adjust the pH to 5, and obtain water reducer S3 with a molecular weight of Mn=22573.

[0049] Example 4

[0050] Preparation of monomer A: In a 250 mL three-necked flask, 50 g of dimethyl sulfoxide and 24.75 g of glycine were added, heated to 80° C., 39.9 g of 4-methylphenyl isocyanate was added dropwise, and reacted for 8 h to obtain a polycondensable carboxyl monomer.

[0051] Preparation of monomer B: 200 g of methoxy polyoxyethylene ether with a molecular weight of Mn=2000 was added to a 500 mL flask, the temperature was raised to 100° C., 25 g of 3,5-dimethylphenyl isocyanate was added dropwise, and the mixture was reacted for 6 h to obtain a polycondensable polyether monomer.

[0052] Preparation of water reducer: Pour the condensable carboxyl monomer and the condensable polyether monomer into a 1000mL flask, add 9g of sulfuric acid, heat to 100°C, add 38.92g of formaldehyde with a concentration of 37%, react for 8h, add water and NaOH after cooling to adjust the pH to 5, and obtain water reducer S4 with a molecular weight Mn=19856.

[0053] Example 5

[0054] Preparation of monomer A: In a 250 mL three-necked flask, add 70 g of N,N-dimethylformamide and 42.24 g of citric acid, heat to 90°C, add 50 g of diphenylmethane diisocyanate dropwise, and react for 5 hours to obtain a polycondensable carboxyl monomer.

[0055] Preparation of Monomer B: 400 g of methoxy polyoxyethylene ether with a molecular weight of Mn=4000 was added to a 500 mL flask, the temperature was raised to 110° C., 12.5 g of phenyl isocyanate was added dropwise, and the mixture was reacted for 3 h to obtain a polycondensable polyether monomer.

[0056] Preparation of water reducer: Pour the condensable carboxyl monomer and the condensable polyether monomer into a 1000 mL flask, add 38.72 g of p-toluenesulfonic acid, heat to 110°C, add 27.08 g of glyoxylic acid dropwise, react for 10 h, cool, add water and NaOH to adjust the pH to 5, and obtain water reducer S5 with a molecular weight of Mn=26415.

[0057] Example 6

[0058] Preparation of monomer A: In a 250 mL three-necked flask, add 60 g of N,N-dimethylformamide and 50.16 g of hydroxyacetic acid, heat to 110° C., add dropwise 79.8 g of 4-methylphenylisocyanate, and react for 3 h to obtain a polycondensable carboxyl monomer.

[0059] Preparation of monomer B: 800 g of methoxy polyoxyethylene ether with a molecular weight of Mn=8000 was added to a 1000 mL flask, the temperature was raised to 90° C., 13.3 g of 4-methylphenyl isocyanate was added dropwise, and the mixture was reacted for 7 h to obtain a polycondensable polyether monomer.

[0060] Preparation of water reducer: Pour the condensable carboxyl monomer and the condensable polyether monomer into a 1000 mL flask, add 28.3 g of phosphoric acid, heat to 120°C, add 62.43 g of formaldehyde with a concentration of 37%, react for 6 hours, cool, add water and NaOH to adjust the pH to 5, and obtain water reducer S6 with a molecular weight of Mn=28646.

[0061] Example 7

[0062] Preparation of monomer A: In a 250 mL three-necked flask, add 50 g of dimethyl sulfoxide and 30 g of glycine, heat to 100° C., dropwise add 58.8 g of 3,5-dimethylphenylisocyanate, and react for 7 h to obtain a polycondensable carboxyl monomer.

[0063] Preparation of Monomer B: 200 g of methoxy polyoxyethylene ether with a molecular weight of Mn=2000 was added to a 500 mL flask, the temperature was raised to 100° C., 13.09 g of phenyl isocyanate was added dropwise, and the mixture was reacted for 8 h to obtain a polycondensable polyether monomer.

[0064] Preparation of water reducer: Pour the condensable carboxyl monomer and the condensable polyether monomer into a 500 mL flask, add 19.6 g of phosphoric acid, heat to 120°C, drop 41.35 g of formaldehyde with a concentration of 37%, react for 6 hours, cool, add water and NaOH to adjust the pH to 5, and obtain water reducer S7 with a molecular weight of Mn=18483.

[0065] Example 8

[0066] Preparation of monomer A: In a 250 mL three-necked flask, add 50 g of N,N-dimethylformamide and 63.36 g of citric acid, heat to 90°C, add dropwise 35.7 g of phenyl isocyanate, react for 6 hours, and obtain a polycondensable carboxyl monomer.

[0067] Preparation of Monomer B: 500 g of methoxy polyoxyethylene ether with a molecular weight of Mn=5000 was added to a 1000 mL flask, the temperature was raised to 100° C., 26.25 g of 3,5-dimethylphenyl isocyanate was added dropwise, and the mixture was reacted for 4 h to obtain a polycondensable polyether monomer.

[0068] Preparation of water reducer: Pour condensable carboxyl monomer and condensable polyether monomer into a 500 mL flask, add 58 g sulfuric acid, heat to 140°C, drop 32.56 g glyoxylic acid, react for 9 h, cool, add water and NaOH to adjust the pH to 5, and obtain water reducer S8 with a molecular weight of Mn=26589.

[0069] Example 9

[0070] Preparation of monomer A: In a 250 mL three-necked flask, add 103 g of dimethyl sulfoxide and 22.5 g of glycine, heat to 90° C., add dropwise 21.75 g of toluene diisocyanate, and react for 4 h to obtain a polycondensable carboxyl monomer.

[0071] Preparation of Monomer B: 200 g of methoxy polyoxyethylene ether with a molecular weight of Mn=2000 was added to a 500 mL flask, the temperature was raised to 120° C., 13.09 g of phenyl isocyanate was added dropwise, and the mixture was reacted for 5 h to obtain a polycondensable polyether monomer.

[0072] Preparation of water reducer: Pour condensable carboxyl monomer and condensable polyether monomer into a 500 mL flask, add 12.2 g of phosphoric acid, heat to 130° C., dropwise add 63.6 g of benzaldehyde, react for 7 h, cool, add water and NaOH to adjust the pH to 5, and obtain water reducer S9 with a molecular weight of Mn=18857.

[0073] Example 10

[0074] Preparation of monomer A: In a 250 mL three-necked flask, add 83 g of dimethyl sulfoxide and 24.75 g of glycine, heat to 110° C., dropwise add 75 g of diphenylmethane diisocyanate, and react for 5 hours to obtain a polycondensable carboxyl monomer.

[0075] Preparation of Monomer B: 200 g of methoxy polyoxyethylene ether with a molecular weight of Mn=2000 was added to a 500 mL flask, the temperature was raised to 110° C., 8.7 g of diphenylmethane diisocyanate was added dropwise, and the mixture was reacted for 3 h to obtain a polycondensable polyether monomer.

[0076] Preparation of water reducer: Pour the condensable carboxyl monomer and the condensable polyether monomer into a 500mL flask, add 17.4g of sulfuric acid, heat to 140°C, add 62.43g of formaldehyde with a concentration of 37%, react for 5h, add water and NaOH after cooling to adjust the pH to 5, and obtain water reducer S10 with a molecular weight Mn=22175.

[0077] Embodiment 11

[0078] Preparation of monomer A: In a 250 mL three-necked flask, add 40 g of N,N-dimethylformamide and 57.6 g of citric acid, heat to 90°C, add dropwise 35.7 g of phenyl isocyanate, and react for 3 h to obtain a polycondensable carboxyl monomer.

[0079] Preparation of Monomer B: 200 g of methoxy polyoxyethylene ether with a molecular weight of Mn=2000 was added to a 500 mL flask, the temperature was raised to 100° C., 11.9 g of phenyl isocyanate was added dropwise, and the mixture was reacted for 4 h to obtain a polycondensable polyether monomer.

[0080] Preparation of water reducer: Pour condensable carboxyl monomer and condensable polyether monomer into a 500 mL flask, add 24.3 g of sulfuric acid, heat to 120° C., drop 21.12 g of acetaldehyde, react for 6 h, cool, add water and NaOH to adjust the pH to 5, and obtain water reducer S11 with a molecular weight of Mn=19364.

[0081] Comparative Example

[0082] A commercially available polycarboxylate water-reducing agent was used as a comparative sample, with a molecular weight Mn of 28685 and named S12.

[0083] Application Examples

[0084] The slurry experiments were carried out using Helin, Conch, Onoda, Benchmark and Zhongshan cements to test the adaptability of the synthesized polycondensation carboxylate water reducer to cement. The results are shown in Table 1.

[0085] Table 1 Cement paste fluidity evaluation table

[0086]

[0087] As can be seen from Table 1, the low-molecular-weight polycondensation carboxylate water reducer prepared by the present invention has good dispersibility, large initial fluidity, good adaptability to cement, good slump retention, and small fluidity loss after 1 hour when the dosage is 0.09%. However, the fluidity of comparative example S12 in different cements is unstable, and the initial fluidity in Helin cement, Onoda cement and reference cement is not much different from that of the synthesized water reducer, and the fluidity in Conch cement and Zhongshan cement is poor, and the fluidity loss is faster.

[0088] The synthesized water reducing agent samples were subjected to machine-made sand mortar experiments, with standard sand and machine-made sand used for the experiments. Mortar mix ratio: 750g of standard cement, 247.5g of water, 1350g of sand, and 0.1% of water reducing agent. The results are shown in Table 2:

[0089] Table 2 Comparison of experimental results of standard sand and machine-made sand mortar

[0090]

[0091] From the results in Table 2, it can be seen that in the mortar of machine-made sand and standard sand, the expansion of machine-made sand is only slightly smaller than that of standard sand, and the fluidity retention performance is better. The control sample has good fluidity in standard sand, but has a large loss in matrix sand and poor fluidity retention performance. The test of machine-made sand mortar shows that the obtained water reducer has better anti-machine-made sand performance than the existing polycarboxylate water reducer.

[0092] Application Example 2

[0093] Referring to the test method of high-performance water reducing agent in the national standard GB8076-2008 "Concrete Admixture", the cement used is Onoda 525.5RPⅡ cement, the sand is medium sand with a fineness modulus Mx=2.6, and the gravel is a continuously graded crushed stone with a particle size of 5-10mm and a particle size of 10-20mm. The water reduction rate, air content, slump retention capacity and other indicators of the polycondensate water reducing agent are tested according to the ratio specified in Table 3, and the test results are shown in Table 4. The dosage of the embodiment is 0.34%.

[0094] Table 3 Test concrete mix ratio

[0095] raw materials cement Fly ash Mineral powder Mechanism sand Small stones Big rocks water <![CDATA[Ratio kg / m 3 > 240 85 75 886 380 570 174

[0096] Table 4 Concrete performance evaluation table

[0097]

[0098] The concrete fluidity data in Table 4 show that the synthesized polycondensation carboxylate water reducer has good dispersibility and slump retention, while the comparison polycarboxylate water reducer S12 has worse slump retention. In addition, the synthesized polycondensation water reducer sample has better air entrainment performance and better working condition, which may be due to the introduction of non-polar benzene ring structure in the main chain.

Claims

1. A highly adaptable polycondensation carboxylate water reducer, characterized in that: It is formed by polycondensation of monomer A, monomer B and monomer C; The monomer A is a phenyl isocyanate compound with a carboxyl group, which is formed by the reaction of a phenyl isocyanate monomer and a carboxyl monomer with a hydroxyl group or an amine group; The monomer B is a phenyl isocyanate compound with a long-chain polyether, which is formed by the reaction of a phenyl isocyanate monomer and a methoxy polyoxyethylene ether monomer; The monomer C is an aldehyde monomer selected from formaldehyde, acetaldehyde, glyoxylic acid, and benzaldehyde; The molar ratio of the monomer A, monomer B and monomer C is: monomer A / monomer B=2-6, monomer C / (monomer A+monomer B)=1-1.

3.

2. The highly adaptable polycondensation carboxylate water reducer according to claim 1, characterized in that: The phenyl isocyanate monomers used to prepare monomer A and monomer B are independently selected from phenyl isocyanate, 4-methylphenyl isocyanate, 3,5-dimethylphenyl isocyanate, diphenylmethane diisocyanate, and toluene diisocyanate.

3. The highly adaptable polycondensation carboxylate water reducer according to claim 1, characterized in that: The carboxyl monomer is selected from glycolic acid, citric acid, glycine, and alanine.

4. The highly adaptable polycondensation carboxylate water reducer according to claim 1, characterized in that: The mass fraction of the methoxy polyoxyethylene ether monomer is Mn=1000-8000.

5. The highly adaptable polycondensation carboxylate water reducer according to claim 1, characterized in that: The weight average molecular weight of the highly adaptable polycondensation carboxylate water reducer is 10,000-30,000.

6. The method for preparing the highly adaptable polycondensation carboxylate water reducer according to any one of claims 1 to 5, characterized in that: The specific steps include: (1) Preparation of monomer A: Add a non-protonic solvent, phenyl isocyanate monomer and carboxyl monomer into a dry flask, react at 60°C-120°C for 2-8 hours to obtain a polycondensable carboxyl monomer, i.e., monomer A; (2) Preparation of Monomer B: Add phenyl isocyanate monomer and methoxy polyoxyethylene ether monomer into a dry flask, react at 80-130° C. for 2-8 hours to obtain a polycondensable polyether macromonomer, i.e., Monomer B; (3) Synthesis of highly adaptable polycondensation carboxylate water reducer: Add the monomers obtained in step 1 and step 2 into a flask, add a protonic acid catalyst and monomer C, and react at 100-150°C for 4-10 hours to obtain a polycondensation carboxylate water reducer.

7. The method for preparing the highly adaptable polycondensation carboxylate water reducer according to claim 6, characterized in that: In the step (1), the aprotic solvent is one of N,N-dimethylformamide and dimethyl sulfoxide, and the solvent content is 30%-70% of the total reactant mass.

8. The method for preparing the highly adaptable polycondensation carboxylate water reducer according to claim 6, characterized in that: In the step (1), the molar ratio of the phenyl isocyanate monomer to the carboxyl monomer is 1:1-1:1.

2.

9. The method for preparing the highly adaptable polycondensation carboxylate water reducer according to claim 6, characterized in that: In the step (2), the molar ratio of the methoxy polyoxyethylene ether monomer to the phenyl isocyanate monomer is 1:1-1:1.

1.

10. The method for preparing the highly adaptable polycondensation carboxylate water reducer according to claim 6, characterized in that: In the step (3), the protonic acid catalyst is one of sulfuric acid, phosphoric acid and p-toluenesulfonic acid, and the content of the protonic acid catalyst accounts for 3%-15% of the total mass of the reactants.

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