Low-sensitivity normal-temperature polycarboxylic acid superplasticizer, and preparation method therefor and use thereof

Abstract

A low-sensitivity normal-temperature polycarboxylic aicd superplasticizer, and a preparation method therefor and the use thereof. The low-sensitivity normal-temperature polycarboxylic acid superplasticizer comprises a six-carbon polyether structural unit, a polyether structural unit containing a benzene ring, a carboxylic acid structural unit and a phosphate structural unit. The polycarboxylic acid superplasticizer can not only greatly alleviate the problem of the poor workability of concrete because a traditional polycarboxylic acid superplasticizer is prone to bleeding and segregation, but also has good adaptability to clay-containing aggregates, and can reduce the sensitivity to floorings, thereby alleviating the problem of a traditional polycarboxylic acid superplasticizer being sensitive to the mixing amount and the water consumption. In addition, the preparation method can further enhance the tolerance of a polymerization system to the pH value, thereby achieving normal-temperature production.

Description

A low-sensitivity room-temperature polycarboxylate water reducer and its preparation method and application

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS

[0002] This application claims priority to the Chinese patent application with application number 202311699102.2, filed with the Chinese Patent Office on December 12, 2023, entitled "A low-sensitive room-temperature polycarboxylate water-reducing agent, its preparation method and application", the entire contents of which are incorporated by reference into this application. Technical Field

[0003] The invention belongs to the field of admixtures, and particularly relates to a low-sensitivity room-temperature polycarboxylate water reducer and a preparation method and application thereof. Background Art

[0004] Polycarboxylate water reducers are the third generation of concrete water reducers. Polycarboxylate water reducers are mainly produced by copolymerizing unsaturated polyether macromonomers with unsaturated carboxylic acids / sulfonic acids. The most common polyether macromonomers on the market include allyl polyethylene glycol ether (APEG), methyl allyl polyethylene glycol ether (HPEG), and isopentenyl polyethylene glycol ether (TPEG). This type of polyether macromonomer has a simple synthesis process, stable chemical properties, and good product quality, but it also has a number of problems. On the one hand, HPEG and TPEG products account for the vast majority of existing polyether macromonomers, and the product structure is relatively simple. On the other hand, during the application of polyether macromonomers, some problems have emerged, such as incompatibility with concrete raw materials and extreme sensitivity to the mud content in sand and gravel. In recent years, the structure of polyether macromonomers has undergone significant changes in the market. Polyether manufacturers have launched new vinyl ether macromonomers, including 2+2 and 2+4 macromonomers (EPEG and VPEG). Vinyl ether macromonomers require a low initial reaction temperature, generally below 20°C. Furthermore, in existing processes, the oxidant is generally added to the substrate all at once, while the reducing agent is added dropwise. This requires refrigeration equipment to control the initial reaction temperature below 20°C. If the initial reaction temperature exceeds 20°C, the dispersion and slump retention properties of the prepared polycarboxylate superplasticizer will be significantly reduced. This drawback has seriously hindered the promotion and application of vinyl ether polyether macromonomers in the superplasticizer industry. Furthermore, polycarboxylate superplasticizers often undergo involution due to their inherent molecular structure instability, resulting in a significant decrease in dispersibility and water reduction rate. However, vinyl ether polycarboxylate superplasticizers prepared at low temperatures are prone to delayed water exudation in downstream applications and are sensitive to the dosage. High dosages can lead to water exudation and segregation, while low dosages can result in slow flow rates.

[0005] Summary of the Invention

[0006] One of the purposes of the present invention is to provide a low-sensitivity room-temperature polycarboxylate water-reducing agent that can achieve room-temperature production, does not require refrigeration equipment, and can improve the delayed bleeding of concrete and is sensitive to the dosage and water consumption.

[0007] A second object of the present invention is to provide a method for preparing a low-sensitivity room-temperature polycarboxylate water-reducing agent.

[0008] A third object of the present invention is to provide a low-sensitivity room-temperature polycarboxylate water-reducing agent prepared by the above method.

[0009] A fourth object of the present invention is to provide an application of the low-sensitivity room-temperature polycarboxylate water-reducing agent.

[0010] Specifically, the low-sensitivity room-temperature polycarboxylate water-reducing agent provided by the present invention includes a six-carbon polyether structural unit, a benzene ring-containing polyether structural unit, a carboxylic acid structural unit, and a phosphate structural unit; the six-carbon polyether structural unit has a structure shown in formula (1); the benzene ring-containing polyether structural unit has a structure shown in formula (2); the carboxylic acid structural unit has a structure shown in formula (3); and the phosphate structural unit has a structure shown in formula (4);

[0011] In formula (1), R 11 is a C1-C5 alkylene group, R 12 、R 13 and R 14 Each is independently H, C1-C5 alkyl or -OH, and n is an integer from 0 to 100;

[0012] In formula (2), R 21 does not exist or is O or C1-C5 alkylene, R 22 does not exist or is a C1-C5 alkylene group, R 23 is H or a C1-C5 alkyl group, and n' is an integer from 0 to 60;

[0013] In formula (3), R 31 and R 32 Each independently represents H, C1-C5 alkyl or -R 33 -COOH and R 31 and R 32 At least one of them is -R 33 -COOH, R 33 does not exist or is a C1-C5 alkylene group; when R 31 and R 32 All are -R 33 -COOH, R 31 and R 32 Able to bond into a ring; R 31 ` and R32 `Each independently is H or C1-C5 alkyl;

[0014] In formula (4), R 41 is O or methylene, R 42 、R 43 and R 44 Each is independently H or a C1-C5 alkyl group, and m, p and q are each independently an integer from 0 to 3.

[0015] The preparation method of the low-sensitivity room-temperature polycarboxylate water-reducing agent provided by the present invention comprises the steps of subjecting an unsaturated hexacarbon polyether macromonomer having a structure represented by formula (5), a benzene ring-containing polyether macromonomer having a structure represented by formula (6), an unsaturated carboxylic acid having a structure represented by formula (7), and a phosphate monomer having a structure represented by formula (8) to a free radical polymerization reaction, wherein the obtained product is a mother liquor of a high-water-reducing polycarboxylate water-reducing agent;

[0016] In formula (5), R 11 is a C1-C5 alkylene group, R 12 、R 13 and R 14 Each is independently H, C1-C5 alkyl or -OH, and n is an integer from 0 to 100;

[0017] In formula (6), R 21 does not exist or is O or C1-C5 alkylene, R 22 does not exist or is a C1-C5 alkylene group, R 23 is H or a C1-C5 alkyl group, and n' is an integer from 0 to 60;

[0018] In formula (7), R 31 and R 32 Each independently represents H, C1-C5 alkyl or -R 33 -COOH and R 31 and R 32 At least one of them is -R 33 -COOH, R 33 does not exist or is a C1-C5 alkylene group; when R 31 and R 32 All are -R 33 -COOH, R 31 and R 32 Able to bond into a ring; R 31 ` and R 32 `Each independently is H or C1-C5 alkyl;

[0019] In formula (8), R 41 is O or methylene, R 42 、R43 and R 44 Each is independently H or a C1-C5 alkyl group, and m, p and q are each independently an integer from 0 to 3.

[0020] The present invention also provides a low-sensitivity room-temperature polycarboxylate water-reducing agent prepared by the above method.

[0021] In addition, the present invention also provides the application of the low-sensitivity room-temperature polycarboxylate water-reducing agent in the field of construction.

[0022] The key to the present invention is to copolymerize an unsaturated six-carbon polyether macromonomer having a structure shown in formula (5), a benzene ring-containing polyether macromonomer having a structure shown in formula (6), an unsaturated carboxylic acid having a structure shown in formula (7), and a phosphate monomer having a structure shown in formula (8) to simultaneously introduce them into the polycarboxylic acid molecular chain, wherein the unsaturated double bond in the unsaturated six-carbon polyether macromonomer is directly bonded to an oxygen atom and has a long polyoxyethylene ether chain segment, and the benzene ring-containing polyether macromonomer contains a benzene ring and the benzene ring is linearly bonded to the unsaturated double bond or is bonded to the unsaturated double bond via an oxygen atom or a short chain sub-molecule. Alkyl groups linked to unsaturated double bonds and possessing long polyoxyethylene ether segments, and phosphate monomers containing phosphate groups linked to unsaturated double bonds via oxygen atoms or short-chain alkylene groups and possessing short-chain alkoxy groups, the synergistic combination of these specific structures not only significantly improves the problem of traditional polycarboxylate water-reducers prone to water exudation and segregation, resulting in poor concrete workability, but also exhibits excellent adaptability to clay-containing aggregates, reduces sensitivity to flooring, and improves the sensitivity of traditional polycarboxylate water-reducers to dosage and water usage. Furthermore, the method provided by the present invention can enhance the polymerization system's tolerance to pH values, enabling room-temperature production. DETAILED DESCRIPTION

[0023] The low-sensitivity room-temperature polycarboxylate water-reducing agent provided by the present invention comprises a six-carbon polyether structural unit, a benzene ring-containing polyether structural unit, a carboxylic acid structural unit, and a phosphate structural unit. Among them, the mass ratio of the total content of the six-carbon polyether structural unit and the benzene ring-containing polyether structural unit, the content of the carboxylic acid structural unit, and the content of the phosphate structural unit is preferably 180:(10-20):(1-5). Based on the total content of the six-carbon polyether structural unit and the benzene ring-containing polyether structural unit as 180 parts by weight, the content of the carboxylic acid structural unit is preferably 10-20 parts by weight, such as 10, 12, 15, 18, 20 parts by weight or any value therebetween; the content of the phosphate structural unit is preferably 1-5 parts by weight, such as 1, 2, 3, 4, 5 parts by weight or any value therebetween. In addition, the mass ratio of the six-carbon polyether structural unit and the benzene ring-containing polyether structural unit is preferably 1:(0.2-1), such as 1:0.2, 1:0.4, 1:0.6, 1:0.8, 1:1 or any value therebetween.

[0024] In the present invention, the six-carbon polyether structural unit has a structure shown in formula (1):

[0025] In formula (1), R 11 is a C1-C5 alkylene group, R 12 、R 13 and R 14 Each is independently H, C1-C5 alkyl or -OH, and n is an integer from 0 to 100. Specific examples of C1-C5 alkylene groups include, but are not limited to, methylene, ethylene, n-propylene, isopropylene, n-butylene, sec-butylene, isobutylene, tert-butylene, n-pentylene, isopentylene, tert-pentylene or neopentylene. Specific examples of C1-C5 alkyl groups include, but are not limited to, methyl, ethyl, n-propyl, isopropyl, n-butyl, sec-butyl, isobutyl, tert-butyl, n-pentyl, isopentyl, tert-pentyl or neopentyl. n can be 0, 1, 5, 10, 15, 20, 25, 30, 40, 50, 60, 70, 80, 90, 100 or any value therebetween. In a preferred embodiment, R 11 is a C1-C5 alkylene group, R 12 、R 13 and R 14 are H, and n is an integer from 20 to 80. The six-carbon polyether structural unit is derived from an unsaturated six-carbon polyether macromonomer, which can be ethylene glycol monovinyl polyethylene glycol ether (EPEG) and / or 4-hydroxybutyl vinyl polyoxyethylene ether (VPEG). In addition, the number average molecular weight of the unsaturated six-carbon polyether macromonomer is preferably 1200 to 6000, such as 1200, 1400, 1600, or any value therebetween.

[0026] In the present invention, the benzene ring-containing polyether structural unit has a structure shown in formula (2):

[0027] In formula (2), R 21 does not exist or is O or C1-C5 alkylene, R 22 does not exist or is a C1-C5 alkylene group, R 23is H or a C1-C5 alkyl group, and n' is an integer from 0 to 60. Specific examples of C1-C5 alkylene groups include, but are not limited to, methylene, ethylene, n-propylene, isopropylene, n-butylene, sec-butylene, isobutylene, tert-butylene, n-pentylene, isopentylene, tert-pentylene, or neopentylene. Specific examples of C1-C5 alkyl groups include, but are not limited to, methyl, ethyl, n-propyl, isopropyl, n-butyl, sec-butyl, isobutyl, tert-butyl, n-pentyl, isopentyl, tert-pentyl, or neopentyl. n' can be 0, 1, 5, 10, 15, 20, 25, 30, 35, 40, 45, 50, 55, 60, or any value therebetween. In a preferred embodiment, R 21 Absent or O or methylene, R 22 does not exist or is methylene or ethylene, R 23 is H or methyl, and n' is an integer of 5 to 60.

[0028] In the present invention, the carboxylic acid structural unit has a structure shown in formula (3):

[0029] In formula (3), R 31 and R 32 Each independently represents H, C1-C5 alkyl or -R 33 -COOH and R 31 and R 32 At least one of them is -R 33 -COOH, R 33 does not exist or is a C1-C5 alkylene group; when R 31 and R 32 All are -R 33 -COOH, R 31 and R 32 Able to bond into a ring; R 31 ` and R 32 `Each independently represents H or a C1-C5 alkyl group. Specific examples of C1-C5 alkyl groups include, but are not limited to, methyl, ethyl, n-propyl, isopropyl, n-butyl, sec-butyl, isobutyl, tert-butyl, n-pentyl, isopentyl, tert-pentyl, or neopentyl. Specific examples of C1-C5 alkylene groups include, but are not limited to, methylene, ethylene, n-propylene, isopropylene, n-butylene, sec-butylene, isobutylene, tert-butylene, n-pentylene, isopentylene, tert-pentylene, or neopentylene. When R 31 and R 32 All are -R 33 -COOH, R 31 and R 32The carboxylic acid structural unit is formed by polymerization of an unsaturated carboxylic acid. Specific examples of the unsaturated carboxylic acid include, but are not limited to, at least one of acrylic acid, methacrylic acid, itaconic acid, and maleic anhydride.

[0030] In the present invention, the phosphate structural unit has a structure shown in formula (4);

[0031] In formula (4), R 41 is O or methylene, R 42 、R 43 and R 44 Each is independently H or a C1-C5 alkyl group, and m, p and q are each independently an integer from 0 to 3. Specific examples of C1-C5 alkyl groups include, but are not limited to, methyl, ethyl, n-propyl, isopropyl, n-butyl, sec-butyl, isobutyl, tert-butyl, n-pentyl, isopentyl, tert-pentyl or neopentyl. m, p and q can be 0, 1, 2 or 3. In a preferred embodiment, R 41 is O or methylene, R 42 、R 43 and R 44 are all H, and m, p and q are integers of 1 to 2.

[0032] In the present invention, the low-sensitivity room-temperature polycarboxylate water-reducing agent is preferably a random copolymer.

[0033] In the present invention, the number average molecular weight of the low-sensitivity room-temperature polycarboxylate water-reducing agent is preferably 10,000 to 80,000, such as 10,000, 20,000, 30,000, 40,000, 50,000, 60,000, 70,000, 80,000 or any value therebetween.

[0034] The preparation method of the low-sensitivity room-temperature polycarboxylate water-reducing agent provided by the present invention comprises subjecting an unsaturated hexacarbon polyether macromonomer, a benzene ring-containing polyether macromonomer, an unsaturated carboxylic acid, and a phosphate ester monomer to a free radical polymerization reaction, resulting in a highly water-reducing polycarboxylate water-reducing agent mother liquor. In one embodiment, the free radical polymerization method comprises: S1, dissolving the unsaturated hexacarbon polyether macromonomer, the benzene ring-containing polyether macromonomer, and an oxidant in a solvent to obtain a substrate; S2, dripping solution A and solution B into the substrate to conduct a free radical copolymerization reaction, wherein solution A is a mixed solution of unsaturated carboxylic acid and unsaturated phosphate ester monomer, and solution B is a mixed solution of a chain transfer agent and a reducing agent.

[0035] In the present invention, the mass ratio of the total amount of the unsaturated hexacarbon polyether macromonomer and the benzene ring-containing polyether macromonomer, the amount of the unsaturated carboxylic acid, and the amount of the phosphate monomer is preferably 180:(10-20):(1-5). Based on the total amount of the unsaturated hexacarbon polyether macromonomer and the benzene ring-containing polyether macromonomer as 180 parts by weight, the amount of the unsaturated carboxylic acid is preferably 10-20 parts by weight, such as 10, 12, 15, 18, 20 parts by weight, or any value therebetween; the amount of the phosphate monomer is preferably 1-5 parts by weight, such as 1, 2, 3, 4, 5 parts by weight, or any value therebetween. In addition, the mass ratio of the unsaturated hexacarbon polyether macromonomer to the benzene ring-containing polyether macromonomer is preferably 1:(0.2-1), such as 1:0.2, 1:0.4, 1:0.6, 1:0.8, 1:1, or any value therebetween.

[0036] In the present invention, the unsaturated six-carbon polyether macromonomer has a structure shown in formula (5):

[0037] In formula (5), R 11 is a C1-C5 alkylene group, R 12 、R 13 and R 14 Each is independently H, C1-C5 alkyl or -OH, and n is an integer from 0 to 100. Specific examples of C1-C5 alkylene groups include, but are not limited to, methylene, ethylene, n-propylene, isopropylene, n-butylene, sec-butylene, isobutylene, tert-butylene, n-pentylene, isopentylene, tert-pentylene or neopentylene. Specific examples of C1-C5 alkyl groups include, but are not limited to, methyl, ethyl, n-propyl, isopropyl, n-butyl, sec-butyl, isobutyl, tert-butyl, n-pentyl, isopentyl, tert-pentyl or neopentyl. n can be 0, 1, 5, 10, 15, 20, 25, 30, 40, 50, 60, 70, 80, 90, 100 or any value therebetween. In a preferred embodiment, R 11 is a C1-C5 alkylene group, R 12 、R 13 and R 14 are all H, and n is an integer from 20 to 80. The unsaturated six-carbon polyether macromonomer can be ethylene glycol monovinyl polyethylene glycol ether (EPEG) and / or 4-hydroxybutyl vinyl polyoxyethylene ether (VPEG). In addition, the number average molecular weight of the unsaturated six-carbon polyether macromonomer is preferably 1200 to 6000, such as 1200, 1400, 1600 or any value therebetween.

[0038] In the present invention, the benzene ring-containing polyether macromonomer has a structure shown in formula (6):

[0039] In formula (6), R21 does not exist or is O or C1-C5 alkylene, R 22 does not exist or is a C1-C5 alkylene group, R 23 is H or a C1-C5 alkyl group, and n' is an integer from 0 to 60. Specific examples of C1-C5 alkylene groups include, but are not limited to, methylene, ethylene, n-propylene, isopropylene, n-butylene, sec-butylene, isobutylene, tert-butylene, n-pentylene, isopentylene, tert-pentylene, or neopentylene. Specific examples of C1-C5 alkyl groups include, but are not limited to, methyl, ethyl, n-propyl, isopropyl, n-butyl, sec-butyl, isobutyl, tert-butyl, n-pentyl, isopentyl, tert-pentyl, or neopentyl. n' can be 0, 1, 5, 10, 15, 20, 25, 30, 35, 40, 45, 50, 55, 60, or any value therebetween. In a preferred embodiment, R 21 Absent or O or methylene, R 22 does not exist or is methylene or ethylene, R 23 is H or methyl, and n' is an integer of 5 to 60.

[0040] In the present invention, the unsaturated carboxylic acid has a structure shown in formula (7):

[0041] In formula (7), R 31 and R 32 Each independently represents H, C1-C5 alkyl or -R 33 -COOH and R 31 and R 32 At least one of them is -R 33 -COOH, R 33 does not exist or is a C1-C5 alkylene group; when R 31 and R 32 All are -R 33 -COOH, R 31 and R 32 Able to bond into a ring; R 31 ` and R 32 `Each independently represents H or a C1-C5 alkyl group. Specific examples of C1-C5 alkyl groups include, but are not limited to, methyl, ethyl, n-propyl, isopropyl, n-butyl, sec-butyl, isobutyl, tert-butyl, n-pentyl, isopentyl, tert-pentyl, or neopentyl. Specific examples of C1-C5 alkylene groups include, but are not limited to, methylene, ethylene, n-propylene, isopropylene, n-butylene, sec-butylene, isobutylene, tert-butylene, n-pentylene, isopentylene, tert-pentylene, or neopentylene. When R 31 and R 32 All are -R 33 -COOH, R 31 and R32 The unsaturated carboxylic acid can be bonded to form a ring, in which case an acid anhydride is formed. In view of the availability of raw materials, the unsaturated carboxylic acid is particularly preferably selected from at least one of acrylic acid, methacrylic acid, itaconic acid and maleic anhydride.

[0042] In the present invention, the unsaturated phosphate monomer has a structure shown in formula (8):

[0043] In formula (8), R 41 is O or methylene, R 42 、R 43 and R 44 Each is independently H or a C1-C5 alkyl group, and m, p and q are each independently an integer from 0 to 3. Specific examples of C1-C5 alkyl groups include, but are not limited to, methyl, ethyl, n-propyl, isopropyl, n-butyl, sec-butyl, isobutyl, tert-butyl, n-pentyl, isopentyl, tert-pentyl or neopentyl. m, p and q can be 0, 1, 2 or 3. In a preferred embodiment, R 41 is O or methylene, R 42 、R 43 and R 44 are all H, and m, p and q are integers of 1 to 2.

[0044] In the preparation process of the above-mentioned low-sensitivity room-temperature polycarboxylate water-reducing agent, specific examples of the oxidizing agent include, but are not limited to, at least one of hydrogen peroxide, ammonium persulfate, potassium persulfate, sodium persulfate, cumene hydroperoxide, dibenzoyl peroxide, and tert-butyl peroxide, preferably a mixture of two or more. Specific examples of the reducing agent include, but are not limited to, at least one of L-ascorbic acid, azobisisopropylimidazoline hydrochloride, azobiscyclohexylcarbonitrile, sodium bisulfite, sodium sulfite, sodium metabisulfite, bleaching agent, ferrous sulfate heptahydrate, sodium hypophosphite, sodium phosphite, and ferrous ammonium sulfate, preferably a mixture of two or more. The amount of the oxidizing agent is preferably 0.3% to 3.0% of the total mass of the unsaturated hexacarbon polyether macromonomer and the benzene ring-containing polyether macromonomer, such as 0.3%, 0.5%, 1%, 1.5%, 2%, 2.5%, 3%, or any value therebetween. The amount of the reducing agent is preferably 0.3% to 3.0% of the total mass of the unsaturated hexacarbon polyether macromonomer and the benzene ring-containing polyether macromonomer, such as 0.3%, 0.5%, 1%, 1.5%, 2%, 2.5%, 3% or any value therebetween.

[0045] In the preparation of the low-sensitivity room-temperature polycarboxylate water-reducing agent, the chain transfer agent is preferably a mercaptan chain transfer agent, more preferably at least one selected from the group consisting of thioglycolic acid, mercaptopropionic acid, mercaptoethanol, and mercaptopropanol. Furthermore, the amount of the chain transfer agent used is preferably 0.1 to 2.0% of the total mass of the unsaturated hexacarbon polyether macromonomer, the benzene ring-containing polyether macromonomer, the unsaturated carboxylic acid, and the phosphate ester monomer, such as 0.1%, 0.3%, 0.5%, 1%, 1.5%, 2%, or any value therebetween.

[0046] During the preparation of the aforementioned low-sensitivity, room-temperature polycarboxylate water-reducing agent, solution A and solution B are separately dripped into a substrate to undergo a free radical copolymerization reaction. The dripping time of solution A is preferably 40 to 70 minutes, such as 40 minutes, 50 minutes, 60 minutes, 70 minutes, or any value therebetween. The dripping time of solution B is preferably 50 to 80 minutes, such as 50 minutes, 60 minutes, 70 minutes, 80 minutes, or any value therebetween.

[0047] In the preparation process of the above-mentioned low-sensitivity room-temperature polycarboxylate water-reducing agent, the conditions of the free radical copolymerization reaction include that the initial dropwise addition temperature is preferably 15 to 40° C., such as 15° C., 20° C., 25° C., 30° C., 35° C., 40° C. or any value therebetween; the reaction time after the dropwise addition of solution A and solution B is preferably 0.5 to 1 h, such as 0.5 h, 0.6 h, 0.7 h, 0.8 h, 0.9 h, 1.0 h or any value therebetween.

[0048] The present invention also provides a low-sensitivity room-temperature polycarboxylate water-reducing agent prepared by the above method.

[0049] The present invention also provides application of the low-sensitivity room-temperature polycarboxylate water-reducing agent in the field of construction.

[0050] The present invention will be described in detail below through examples.

[0051] Example 1

[0052] S1, 120g of 3000 number average molecular weight ethylene glycol monovinyl polyethylene glycol ether, 60g of benzene ring-containing polyether macromonomer (having the structure shown in formula (6), R 21 Does not exist, R 22 is methylene, R 23 H, number average molecular weight of 3000), 1.5 g of hydrogen peroxide and 150 g of deionized water were added to the reaction container and mixed evenly to obtain a substrate;

[0053] S2, solution A (unsaturated phosphate monomer (having the structure shown in formula (8), R 41 O, R 42 、R 43and R 44 The reaction mixture is added dropwise to the reaction vessel to carry out the reaction. The reaction mixture is H, m, p and q are ...

[0054] Example 2

[0055] S1, 90g of ethylene glycol monovinyl polyethylene glycol ether with a number average molecular weight of 3000, 90g of a benzene ring-containing polyether macromonomer (having a structure shown in formula (6), R 21 O, R 22 is ethylene, R 23 H, number average molecular weight of 2400), 1.5 g of hydrogen peroxide, 150 g of deionized water, and 0.004 g of ferrous sulfate were added to a reaction container and mixed to obtain a substrate;

[0056] S2, solution A (unsaturated phosphate monomer (having the structure shown in formula (8), R 41 O, R 42 、R 43 and R 44 where H, m, p and q are H, m, p and q are 1) a mixed solution of 2 g, 16.0 g of acrylic acid and 10.0 g of water) and B solution (a mixed solution of 0.25 g of ascorbic acid, 0.8 g of mercaptopropionic acid and 20.0 g of water) are respectively added dropwise to the reaction vessel to react, the initial reaction temperature is 40 ° C, the dropwise addition time of solution A is 60 min, the dropwise addition time of solution B is 70 min, and the temperature is kept warm for 1 hour after the addition is completed. After the insulation is completed, the temperature is cooled to room temperature to obtain a low-sensitive room temperature polycarboxylate water-reducing agent mother liquor.

[0057] Example 3

[0058] S1, 100g of 3000 number average molecular weight ethylene glycol monovinyl polyethylene glycol ether, 80g of benzene ring-containing polyether macromonomer (having the structure shown in formula (6), R 21 is methylene, R 22 is ethylene, R 23 H, number average molecular weight of 2600), 1.2 g of hydrogen peroxide, 150 g of deionized water, and 0.7 g of sodium hypophosphite were added to a reaction container and mixed uniformly to obtain a substrate;

[0059] S2, solution A (2g unsaturated phosphate monomer (having the structure shown in formula (8), R 41 is methylene, R 42、R 43 and R 44 is H, m, p and q are 1), a mixed solution of 16.0 g of acrylic acid and 10.0 g of water) and a mixed solution B (0.15 g of ascorbic acid, 0.15 g of bleaching powder, 0.8 g of mercaptopropionic acid and 20.0 g of water) were respectively dropped into the reaction container to react, the initial reaction temperature was 35°C, the dropwise addition time of solution A was 40 min, the dropwise addition time of solution B was 50 min, and the temperature was kept warm for 1 hour after the addition was completed. After the insulation was completed, the temperature was cooled to room temperature to obtain a low-sensitive room-temperature polycarboxylate water-reducing agent mother liquor.

[0060] Comparative Example 1

[0061] A low-sensitivity room-temperature polycarboxylate water-reducing agent was prepared according to the method of Example 1, except that the benzene ring-containing polyether macromonomer was replaced by ethylene glycol monovinyl polyethylene glycol ether (number average molecular weight of 3000) in equal parts by weight. The remaining conditions were the same as in Example 1 to obtain a low-sensitivity room-temperature polycarboxylate water-reducing agent.

[0062] Comparative Example 2

[0063] A low-sensitivity room-temperature polycarboxylate water reducer was prepared according to the method of Example 1, except that the unsaturated phosphate monomer was replaced by acrylic acid in the same parts by weight. The other conditions were the same as in Example 1 to obtain a low-sensitivity room-temperature polycarboxylate water reducer.

[0064] Comparative Example 3

[0065] Point-MS407, a hexacarbonyl polycarboxylic acid water reducer produced by Kezhijie New Materials Group at low temperature (15°C).

[0066] Test Case

[0067] (1) The fluidity of the polycarboxylate superplasticizers obtained in the above examples and comparative examples at different superplasticizer dosages and water amounts was tested in accordance with GB / T 8077-2012, "Test Method for Homogeneity of Concrete Admixtures." In the tests at different superplasticizer dosages, the cement dosage was 300 g and the water dosage was 87 g. The results are shown in Table 1. In the tests at different water dosages, the cement dosage was 300 g and the superplasticizer dosage was 0.11%. The results are shown in Table 2.

[0068] Table 1

[0069] Table 2

[0070] It can be seen from the test results in Table 1 and Table 2 that the polycarboxylate water-reducing agent provided by the present invention is relatively insensitive in terms of dosage and water consumption.

[0071] (2) Concrete was prepared according to the mix ratio in Table 3. The mother liquor obtained in the above examples and comparative examples was diluted into a 10% solid water-reducing agent dilution solution before the concrete test. The amount of the water-reducing agent dilution solution was 2.0%. The performance indicators were then tested according to the test method in accordance with GB / T 50080-2016 "Standard for Test Methods of Performance of Ordinary Concrete Mixtures". The results are shown in Table 4.

[0072] Table 3 (parts by weight)

[0073] Table 4

[0074] The results in Table 4 show that the polycarboxylate water-reducing agent provided by the present invention has a low bleeding rate and produces good concrete. Furthermore, the present invention enables room-temperature production during the preparation of the polycarboxylate water-reducing agent, eliminating the need for refrigeration equipment and demonstrating broad application prospects.

[0075] Although the embodiments of the present invention have been shown and described above, it will be understood that the above embodiments are illustrative and are not to be construed as limitations on the present invention. A person skilled in the art may change, modify, replace and modify the above embodiments within the scope of the present invention without departing from the principles and purpose of the present invention.

Claims

1. A low-sensitivity room-temperature polycarboxylate water reducer, It is characterized in that The low-sensitivity room-temperature polycarboxylate water-reducing agent comprises a six-carbon polyether structural unit, a benzene ring-containing polyether structural unit, a carboxylic acid structural unit and a phosphate structural unit; the six-carbon polyether structural unit has a structure shown in formula (1); the benzene ring-containing polyether structural unit has a structure shown in formula (2); the carboxylic acid structural unit has a structure shown in formula (3); and the phosphate structural unit has a structure shown in formula (4); In formula (1), R 11 C 1 -C 5 The alkylene group, R 12 , R 13 and R 14 Each independently is H, C 1 -C 5 An alkyl group or -OH, n is an integer from 0 to 100; In formula (2), R 21 Not present or O or C 1 -C 5 The alkylene group, R 22 Does not exist or is C 1 -C 5 The alkylene group, R 23 H or C 1 -C 5 An alkyl group, n' is an integer from 0 to 60; In formula (3), R 31 and R 32 Each independently is H, C 1 -C 5 Alkyl or -R 33 -COOH and R 31 and R 32 At least one of them is -R 33 -COOH, R 33 Does not exist or is C 1 -C 5 Alkylene; when R 31 and R 32 All are -R 33 -COOH, R 31 and R 32 Able to bond into a ring; R 31 ` and R 32 `Each independently is H or C 1 -C 5 The alkyl group; In formula (4), R 41 is O or methylene, R 42 , R 43 and R 44 Each independently is H or C 1 -C 5 wherein m, p and q are each independently an integer of 0 to 3.

2. The low-sensitivity room-temperature polycarboxylate water-reducing agent according to claim 1, It is characterized in that The mass ratio of the total content of the six-carbon polyether structural unit and the benzene ring-containing polyether structural unit, the content of the carboxylic acid structural unit and the content of the phosphate structural unit is 180:(10-20):(1-5); the mass ratio of the six-carbon polyether structural unit and the benzene ring-containing polyether structural unit is 1:(0.2-1).

3. The low-sensitivity room-temperature polycarboxylate water-reducing agent according to claim 1, It is characterized in that The low-sensitivity room-temperature polycarboxylate water-reducing agent is a random copolymer; preferably, the number average molecular weight of the low-sensitivity room-temperature polycarboxylate water-reducing agent is 10,000-80,000.

4. A method for preparing a low-sensitivity room-temperature polycarboxylate water-reducing agent, It is characterized in that The method comprises subjecting an unsaturated hexacarbon polyether macromonomer having a structure shown in formula (5), a benzene ring-containing polyether macromonomer having a structure shown in formula (6), an unsaturated carboxylic acid having a structure shown in formula (7) and a phosphate ester monomer having a structure shown in formula (8) to a free radical polymerization reaction, wherein the obtained product is a high water-reducing polycarboxylic acid water-reducing agent mother liquor; In formula (5), R 11 C 1 -C 5 The alkylene group, R 12 , R 13 and R 14 Each independently is H, C 1 -C 5 An alkyl group or -OH, n is an integer from 0 to 100; In formula (6), R 21 Not present or O or C 1 -C 5 The alkylene group, R 22 Does not exist or is C 1 -C 5 The alkylene group, R 23 H or C 1 -C 5 An alkyl group, n' is an integer from 0 to 60; In formula (7), R 31 and R 32 Each independently is H, C 1 -C 5 Alkyl or -R 33 -COOH and R 31 and R 32 At least one of them is -R 33 -COOH, R 33 Does not exist or is C 1 -C 5 Alkylene; when R 31 and R 32 All are -R 33 -COOH, R 31 and R 32 Able to bond into a ring; R 31 ` and R 32 `Each independently is H or C 1 -C 5 The alkyl group; In formula (8), R 41 is O or methylene, R 42 , R 43 and R 44 Each independently is H or C 1 -C 5 wherein m, p and q are each independently an integer of 0 to 3.

5. The method for preparing the low-sensitivity room-temperature polycarboxylate water-reducing agent according to claim 4, It is characterized in that The free radical polymerization method comprises: S1, dissolving an unsaturated six-carbon polyether macromonomer, a benzene ring-containing polyether macromonomer and an oxidant in a solvent to obtain a substrate; S2. respectively dropping solution A and solution B into the substrate to carry out free radical copolymerization reaction, wherein solution A is a mixed solution of unsaturated carboxylic acid and unsaturated phosphate monomer, and solution B is a mixed solution of chain transfer agent and reducing agent.

6. The method for preparing the low-sensitivity room-temperature polycarboxylate water-reducing agent according to claim 4, It is characterized in that The mass ratio of the total amount of the unsaturated six-carbon polyether macromonomer and the benzene ring-containing polyether macromonomer, the amount of the unsaturated carboxylic acid and the amount of the phosphate monomer is 180:(10-20):(1-5); the mass ratio of the unsaturated six-carbon polyether macromonomer and the benzene ring-containing polyether macromonomer is 1:(0.2-1).

7. The method for preparing the low-sensitivity room-temperature polycarboxylate water-reducing agent according to claim 4, It is characterized in that The unsaturated six-carbon polyether macromonomer is ethylene glycol monovinyl polyethylene glycol ether and / or 4-hydroxybutyl vinyl polyoxyethylene ether; the number average molecular weight of the unsaturated six-carbon polyether macromonomer is 1200-6000.

8. The method for preparing the low-sensitivity room-temperature polycarboxylate water-reducing agent according to claim 4, It is characterized in that The R 21 Absent or O or methylene, R 22 does not exist or is methylene or ethylene, R 23 is H or methyl; preferably, the number average molecular weight of the benzene ring-containing polyether macromonomer is 2000-3000.

9. The method for preparing the low-sensitivity room-temperature polycarboxylate water-reducing agent according to claim 4, It is characterized in that The unsaturated carboxylic acid is at least one selected from acrylic acid, methacrylic acid, itaconic acid and maleic anhydride.

10. The method for preparing the low-sensitivity room-temperature polycarboxylate water-reducing agent according to claim 4, It is characterized in that The oxidant is selected from at least one of hydrogen peroxide, ammonium persulfate, potassium persulfate, sodium persulfate, cumene hydroperoxide, dibenzoyl peroxide and tert-butyl peroxide; Preferably, the reducing agent is selected from at least one of L-ascorbic acid, azobisisopropylimidazoline hydrochloride, azobiscyclohexylcarbonitrile, sodium bisulfite, sodium sulfite, sodium pyrosulfite, chlorinated acetic acid, ferrous sulfate heptahydrate, sodium hypophosphite, sodium phosphite and ammonium ferrous sulfate; Preferably, the chain transfer agent is a mercaptan chain transfer agent, more preferably at least one selected from thioglycolic acid, mercaptopropionic acid, mercaptoethanol and mercaptopropanol; Preferably, the amount of the oxidant is 0.3% to 3.0% of the total mass of the unsaturated six-carbon polyether macromonomer and the benzene ring-containing polyether macromonomer; Preferably, the amount of the reducing agent is 0.3% to 3.0% of the total mass of the unsaturated six-carbon polyether macromonomer and the benzene ring-containing polyether macromonomer; Preferably, the amount of the chain transfer agent is 0.1 to 2.0% of the total mass of the unsaturated six-carbon polyether macromonomer, the benzene ring-containing polyether macromonomer, the unsaturated carboxylic acid and the phosphate ester monomer; Preferably, the dropwise addition time of solution A is 40 to 70 minutes; Preferably, the dropwise addition time of the B solution is 50 to 80 minutes; Preferably, the conditions of the free radical copolymerization reaction include an initial dropwise addition temperature of 15 to 40° C., and a reaction time of 0.5 to 1 h after both solution A and solution B are dropwise added.

11. A low-sensitivity room-temperature polycarboxylate water-reducing agent prepared by the method according to any one of claims 4 to 10.

12. Use of the low-sensitivity room-temperature polycarboxylate water-reducing agent according to any one of claims 1 to 3 and 11 in the field of construction.

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