Ether-based polycarboxylic acid slump retainer, preparation method therefor and use thereof

Abstract

The present invention relates to the technical field of concrete admixtures, and in particular, to an ether-based polycarboxylic acid slump retainer, a preparation method therefor and a use thereof. The method for preparing the ether-based polycarboxylic acid slump retainer comprises: carrying out an esterification reaction between vinyl phthalic acid and polyethylene glycol, and then carrying out a free radical polymerization reaction between the resulting esterified functional monomer and an unsaturated polyether monomer, an unsaturated carboxylic acid monomer, and a hydroxycarboxylic acid ester monomer. The key point of the present invention lies in the free radical copolymerization of the esterified functional monomer having a specific structure and the hydroxycarboxylic acid ester monomer with the unsaturated polyether monomer and the unsaturated carboxylic acid monomer, and the resulting polycarboxylic acid slump retainer can reduce the sensitivity of concrete, improve the workability of concrete, improve the mud resistance, reduce slump loss, reduce the sensitivity to raw material changes, facilitate the pumping of manufactured sand concrete, pumped concrete, etc., and effectively improve the construction efficiency of concrete.

Description

An ether polycarboxylic acid collapse retaining agent 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 202311794952.0 filed with the Patent Office of China on December 25, 2023, entitled "An ether-based polycarboxylic acid collapse retaining agent, its preparation method and application", the entire contents of which are incorporated by reference into this application. Technical Field

[0003] The present invention relates to the technical field of concrete admixtures, and in particular to an ether polycarboxylic acid slump retaining agent, a preparation method and application thereof. Background Art

[0004] With the rapid development of the construction industry, the market for commercial concrete is in short supply, and the development of concrete admixtures has entered a new era. The use of concrete and cement is increasing continuously, and polycarboxylic acid slump retaining agent, as one of the important admixtures for concrete, is also a hot spot in concrete research and development.

[0005] Polycarboxylic acid slump retaining agent is a functional admixture commonly used in the concrete production process. Although the excellent slump retaining performance of polycarboxylic acid slump retaining agent has been widely recognized by the industry, due to the increasingly poor quality of sand and stone materials (high mud content and stone powder content), polycarboxylic acid slump retaining agent has also appeared in actual application. The problems such as high sensitivity to raw material changes, excessive slump loss and poor workability. In addition, after decades of rapid development of urban construction, the natural resources of concrete raw materials are consumed greatly, and high-quality sand and stone resources are almost exhausted. It has become an inevitable trend to apply low-quality aggregates such as construction solid waste, machine-made sand and natural sand and gravel with high mud content to concrete. The high sensitivity of polycarboxylic acid slump retaining agent during use often leads to problems such as rapid concrete loss and pipe blocking, which seriously affects the concrete pumping construction performance, and then affects the mechanical properties and durability of the later stage. Therefore, how to reduce the sensitivity of polycarboxylic acid slump retaining agent to raw material changes while improving slump retaining performance and workability has become a technical problem that needs to be solved urgently.

[0006] Summary of the Invention

[0007] One of the purposes of the present invention is to provide a method for preparing an ether polycarboxylic acid slump retaining agent which has low sensitivity to raw materials and has good slump retaining performance and workability.

[0008] A second object of the present invention is to provide an ether polycarboxylic acid collapse retaining agent prepared by the above method.

[0009] A third object of the present invention is to provide an application of the ether polycarboxylic acid collapse retaining agent in the field of construction.

[0010] The preparation method of the ether polycarboxylic acid collapse-preventing agent provided by the present invention comprises the following steps:

[0011] S1, esterifying vinyl phthalic acid with polyethylene glycol, wherein the vinyl phthalic acid has a structure shown in formula (1), to obtain an esterification functional monomer;

[0012] S2, conducting a free radical polymerization reaction of an esterification functional monomer with an unsaturated polyether monomer, an unsaturated carboxylic acid monomer, and a carboxylic acid hydroxy ester monomer, wherein the carboxylic acid hydroxy ester monomer contains compound A represented by formula (2-1) and compound B represented by formula (2-2), and the resulting polymerization product is an ether-based polycarboxylic acid collapse retaining agent;

[0013] In formula (2-1), R 21 is H or C1-C5 alkyl, R 22 is a C0-C4 alkylene group, R 23 is a C1-C5 alkylene group;

[0014] In formula (2-2), R 21 is H or C1-C5 alkyl, R 23 is a C1-C5 alkylene group;

[0015] In formula (3), R 31 is a C1-C5 alkylene group, R 32 、R 33 and R 34 Each is independently H, C1-C5 alkyl or -OH, and n is an integer from 1 to 100.

[0016] The present invention also provides an ether polycarboxylic acid collapse-preventing agent prepared by the above method.

[0017] The present invention also provides application of the ether polycarboxylic acid collapse preventing agent in the field of construction.

[0018] The key to the present invention is to free radical copolymerize an esterified functional monomer and a carboxylic acid hydroxy ester monomer having a specific structure with an unsaturated polyether monomer and an unsaturated carboxylic acid monomer. The resulting polycarboxylic acid slump retaining agent can reduce the sensitivity of concrete, improve the workability of concrete, improve mud resistance, reduce slump loss, and reduce sensitivity to changes in raw materials. This is beneficial for the pumping of machine-made sand concrete, pumped concrete, etc., and effectively improves concrete construction efficiency. It is speculated that the reason for this may be that the copolymerization of the above monomers can not only make the side chains of the polycarboxylic acid slump retaining agent molecules more stretched, the steric hindrance effect is more obvious, and the viscosity of concrete can be effectively reduced, making it less prone to mud intercalation and adsorption, improving mud resistance, enhancing workability, and reducing sensitivity to changes in raw materials, but also effectively compensating for the early slump loss, improving the slump retention performance of concrete, and extending the slump time of concrete. DETAILED DESCRIPTION

[0019] The preparation method of the ether polycarboxylic acid collapse-preventing agent provided by the present invention comprises the following steps:

[0020] S1, esterifying vinyl phthalic acid and polyethylene glycol to obtain an esterification functional monomer;

[0021] S2. Conducting a free radical polymerization reaction between the esterification functional monomer and the unsaturated polyether monomer, the unsaturated carboxylic acid monomer and the carboxylic acid hydroxy ester monomer, and the obtained polymerization product is an ether polycarboxylic acid collapse retaining agent.

[0022] In the present invention, the mass ratio of the unsaturated polyether monomer, the unsaturated carboxylic acid monomer, the esterification functional monomer and the carboxylic acid hydroxy ester monomer is preferably 200:(5-10):(5-20):(10-30). Based on 200 parts by weight of the unsaturated polyether monomer, the amount of the unsaturated carboxylic acid monomer is preferably 5-10 parts by weight, such as 5, 6, 7, 8, 9, 10 parts by weight or any value therebetween; the content of the esterification functional monomer is preferably 5-20 parts by weight, such as 5, 8, 10, 12, 15, 18, 20 parts by weight or any value therebetween; and the content of the carboxylic acid hydroxy ester structural unit is preferably 10-30 parts by weight, such as 10, 12, 15, 18, 20, 22, 25, 28, 30 parts by weight or any value therebetween.

[0023] In the preparation process of the esterification functional monomer, the molar ratio of vinyl phthalic acid to polyethylene glycol is preferably (2-4):1, such as 2:1, 2.5:1, 3:1, 3.5:1, 5:1 or any value therebetween.

[0024] In the preparation process of the above-mentioned esterification functional monomer, the vinyl phthalic acid has a structure shown in formula (1), and its specific example includes but is not limited to: 4-vinyl-1,2-phthalic acid.

[0025] In the preparation process of the above-mentioned esterification functional monomer, specific examples of the polyethylene glycol include, but are not limited to, at least one of PEG-200, PEG-400, PEG-600, PEG-800 and PEG-1000.

[0026] In the preparation process of the above-mentioned esterification functional monomer, the conditions of the esterification reaction preferably include a temperature of 80°C to 100°C, such as 80°C, 82°C, 85°C, 88°C, 90°C, 92°C, 95°C, 98°C, 100°C or any value therebetween; and a time of 1 to 5h, such as 1h, 1.5h, 2h, 2.5h, 3h, 3.5h, 4h, 4.5h, 5h or any value therebetween.

[0027] In the preparation process of the above-mentioned esterification functional monomer, the esterification reaction is preferably carried out in the presence of a catalyst and a polymerization inhibitor. The catalyst can be any existing substance capable of catalyzing the esterification reaction, and specific examples thereof include but are not limited to at least one of concentrated sulfuric acid, p-toluenesulfonic acid, stannous oxide, and dibutyltin oxide. The amount of the catalyst used preferably accounts for 1% to 3% of the total mass of the vinyl phthalic acid and polyethylene glycol, such as 1%, 1.2%, 1.5%, 1.8%, 2%, 2.2%, 2.5%, 2.8%, 3%, or any value therebetween. Specific examples of the polymerization inhibitor include but are not limited to at least one of p-hydroxyanisole, hydroquinone, and phenothiazine. The amount of the polymerization inhibitor used preferably accounts for 0.1% to 2% of the total mass of the vinyl phthalic acid and polyethylene glycol, such as 1%, 1.2%, 1.5%, 1.8%, 2%, or any value therebetween.

[0028] In the present invention, the carboxylic acid hydroxy ester monomer contains compound A represented by formula (2-1) and compound B represented by formula (2-2). The mass ratio of compound A to compound B in the carboxylic acid hydroxy ester monomer is preferably 1:(2-4), such as 1:2, 1:2.2, 1:2.5, 1:2.8, 1:3, 1:3.2, 1:3.5, 1:3.8, 1:4 or any value therebetween. The compound A and compound B used in combination according to this preferred ratio have the advantage of having a strong ability to maintain slump for a long time.

[0029] In formula (2-1), R 21 is H or C1-C5 alkyl, R 22 is a C0-C4 alkylene group, R 23 is a C1 to C5 alkylene group. In formula (2-2), R 21 is H or C1-C5 alkyl, R 23 It is a C1 to C5 alkylene group. Specific examples of C1 to 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 C0 to C4 alkylene groups include, but are not limited to, absence, methylene, ethylene, n-propylene, isopropylene, n-butylene, sec-butylene, isobutylene or tert-butylene. Specific examples of C1 to 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. In the present invention, the unsaturated polyether monomer preferably has a structure shown in formula (3):

[0030] In formula (3), R 31is a C1-C5 alkylene group, R 32 、R 33 and R 34 Each is independently H, C1-C5 alkyl or -OH, and n is an integer from 1 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, 5, 10, 20, 30, 40, 50, 60, 70, 80, 90, 100 or any value therebetween. In a preferred embodiment, R 31 is a C1-C5 alkylene group, R 32 、R 33 and R 34 are all H, and n is an integer from 20 to 60. The unsaturated polyether macromonomer may be at least one of vinyl polyoxyethylene ether, methyl vinyl polypropylene glycol ether, ethylene glycol monovinyl polyethylene glycol ether (EPEG), and 4-hydroxybutyl vinyl polyethylene glycol ether (VPEG). In addition, the number average molecular weight of the unsaturated polyether macromonomer is preferably 1200 to 6000, such as 1200, 1400, 1600, or any value therebetween.

[0031] In the present invention, the unsaturated carboxylic acid monomer preferably has a structure represented by formula (4):

[0032] In formula (4), R 41 and R 42 Each independently represents H, C1-C5 alkyl or -R 43 -COOH and R 41 and R 42 At least one of them is -R 43 -COOH, R 43 is a C0-C5 alkylene group; when R 41 and R 42 All are -R 43 -COOH, R 41 and R 42 Able to bond into a ring; R 41 ` and R 42`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 C0-C5 alkylene groups include, but are not limited to, absence, methylene, ethylene, n-propylene, isopropylene, n-butylene, sec-butylene, isobutylene, tert-butylene, n-pentylene, isopentylene, tert-pentylene, or neopentylene. 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 41 and R 42 All are -R 43 -COOH, R 41 and R 42 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 at least one selected from acrylic acid, methacrylic acid, itaconic acid and maleic anhydride.

[0033] The present invention does not particularly limit the type of initiator used in the free radical polymerization reaction, and the initiator may be at least one selected from an azo initiator, a peroxide initiator, and a redox initiator. Specific examples of the azo initiator include, but are not limited to, at least one of dimethyl azobisisobutyrate, azobisisobutyramidine hydrochloride, azodicarbonamide, azobisisopropylimidazoline hydrochloride, azoisobutylcyanamide, azobiscyclohexylcarbonitrile, azobiscyanovaleric acid, azobisisopropylimidazoline, azobisisobutyronitrile, azobisisovaleronitrile, and azobisisoheptylonitrile. Specific examples of the peroxide initiator include, but are not limited to, at least one of hydrogen peroxide, ammonium persulfate, sodium persulfate, potassium persulfate, benzoyl peroxide, and tert-butyl benzoyl peroxide. The redox initiator includes an oxidizing agent and a reducing agent, and specific examples include, but are not limited to, at least one of sulfate-sulfite, persulfate-thiourea, persulfate-organic salt, and ammonium persulfate-fatty amine. The sulfate-sulfite may be selected from at least one of sodium sulfate-sodium sulfite, potassium sulfate-potassium sulfite, and ammonium sulfate-ammonium sulfite. The persulfate-thiourea may be selected from at least one of sodium persulfate-thiourea, potassium persulfate-thiourea, and ammonium persulfate-thiourea. The persulfate-organic salt may be selected from at least one of sodium persulfate-potassium acetate, potassium persulfate-potassium acetate, and ammonium persulfate-ammonium acetate. The ammonium persulfate-fatty amine may be ammonium persulfate-N,N-tetramethylethylenediamine and / or ammonium persulfate-diethylamine. The free radical polymerization reaction preferably employs a redox initiator.

[0034] In a preferred embodiment, the free radical polymerization reaction comprises:

[0035] S1`, dissolving an unsaturated polyether monomer and an oxidant in water to obtain a substrate;

[0036] S2', respectively dropwise adding solution A and solution B into the substrate to carry out polymerization reaction, wherein solution A is a reducing agent solution, and solution B is a mixed solution of esterification functional monomer, unsaturated carboxylic acid monomer, carboxylic acid hydroxy ester monomer and molecular weight regulator. After the reaction is completed, the product obtained is an ether polycarboxylic acid collapse retaining agent.

[0037] In the preparation process of the above-mentioned ether-based polycarboxylic acid collapse-preventing 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 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 1% to 5% of the total mass of the unsaturated polyether monomer, such as 1%, 1.5%, 2%, 2.5%, 3%, 3.5%, 4%, 4.5%, 5%, or any value therebetween. The amount of the reducing agent is preferably 0.1% to 2% of the total mass of the unsaturated polyether monomer, such as 0.1%, 0.3%, 0.5%, 1%, 1.5%, 2% or any value therebetween.

[0038] In the preparation process of the above-mentioned ether-based polycarboxylic acid collapse-preventing agent, the molecular weight regulator is preferably a thiol compound, more preferably one selected from the group consisting of thioglycolic acid, mercaptopropionic acid, mercaptoethanol, and mercaptopropanol. In addition, the molecular weight regulator is preferably used in an amount of 1% to 5% of the total mass of the unsaturated polyether monomer, such as 1%, 1.5%, 2%, 2.5%, 3%, 3.5%, 4%, 4.5%, 5%, or any value therebetween.

[0039] In the preparation process of the above-mentioned ether-based polycarboxylic acid collapse retaining agent, solution A and solution B are respectively dripped into the substrate to carry out free radical polymerization reaction. The dripping time of the solution A is preferably 120 to 180 minutes, such as 120 minutes, 130 minutes, 140 minutes, 150 minutes, 160 minutes, 170 minutes, 180 minutes or any value therebetween. The dripping time of the solution B is preferably 120 to 180 minutes, such as 120 minutes, 130 minutes, 140 minutes, 150 minutes, 160 minutes, 170 minutes, 180 minutes or any value therebetween.

[0040] In the preparation process of the above-mentioned ether polycarboxylic acid collapse retaining agent, the conditions of the free radical polymerization reaction preferably include a temperature of 15 to 40° C., such as 15° C., 20° C., 25° C., 30° C., 35° C., 40° C. or any value therebetween; and a reaction time after the solution is added dropwise of 20 to 60 min, such as 20 min, 25 min, 30 min, 35 min, 40 min, 45 min, 50 min, 55 min, 60 min or any value therebetween.

[0041] The present invention also provides an ether polycarboxylic acid collapse-preventing agent prepared by the method.

[0042] The ether polycarboxylic acid collapse retaining agent provided by the present invention comprises a polyether structural unit, a carboxylic acid structural unit, an esterification functional structural unit and a carboxylic acid hydroxy ester structural unit. The mass ratio of the polyether structural unit, the carboxylic acid structural unit, the esterification functional structural unit and the carboxylic acid hydroxy ester structural unit is 200:(5-10):(5-20):(10-30). Based on the content of the polyether structural unit as 200 parts by weight, the content of the carboxylic acid structural unit is 5-10 parts by weight, such as 5, 6, 7, 8, 9, 10 parts by weight or any value therebetween; the content of the esterification functional structural unit is 5-20 parts by weight, such as 5, 8, 10, 12, 15, 18, 20 parts by weight or any value therebetween; the content of the carboxylic acid hydroxy ester structural unit is 10-30 parts by weight, such as 10, 12, 15, 18, 20, 22, 25, 28, 30 parts by weight or any value therebetween.

[0043] In the present invention, the esterification functional structural unit has a structure represented by at least one of formula (5-1), formula (5-2) and formula (5-3):

[0044] In formula (5-1) to formula (5-3), n is an integer from 1 to 100, such as 1, 2, 5, 10, 20, 30, 40, 50, 60, 70, 80, 90, 100 or any value therebetween.

[0045] In the present invention, the carboxylic acid hydroxy ester structural unit has the structures shown in Formula (6-1) and Formula (6-2).

[0046] In formula (6-1), R 21 is H or C1-C5 alkyl, R 22 is a C0-C4 alkylene group, R 23 is a C1 to C5 alkylene group. 21 is H or C1-C5 alkyl, R 23is a C1-C5 alkylene 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 C0-C5 alkylene groups include, but are not limited to, absence, methylene, ethylene, n-propylene, isopropylene, n-butylene, sec-butylene, isobutylene, tert-butylene, n-pentylene, isopentylene, tert-pentylene, or neopentylene. Specific examples of C0-C4 alkylene groups include, but are not limited to, absence, methylene, ethylene, n-propylene, isopropylene, n-butylene, sec-butylene, isobutylene, or tert-butylene.

[0047] In the present invention, the polyether structural unit preferably has a structure shown in formula (7):

[0048] In formula (7), R 31 is a C1-C5 alkylene group, R 32 、R 33 and R 34 Each is independently H, C1-C5 alkyl or -OH, and n is an integer from 1 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, 5, 10, 20, 30, 40, 50, 60, 70, 80, 90, 100 or any value therebetween. In a preferred embodiment, R 31 is a C1-C5 alkylene group, R 32 、R 33 and R 34 are all H, and n is an integer from 20 to 60. The polyether structural unit is formed by polymerization of unsaturated polyether monomers. The unsaturated polyether macromonomer can be at least one of vinyl polyoxyethylene ether, methyl vinyl polypropylene glycol ether, ethylene glycol monovinyl polyethylene glycol ether (EPEG), and 4-hydroxybutyl vinyl polyethylene glycol ether (VPEG). In addition, the number average molecular weight of the unsaturated polyether macromonomer is preferably 1200 to 6000, such as 1200, 1400, 1600, or any value therebetween.

[0049] In the present invention, the carboxylic acid structural unit has a structure shown in formula (8):

[0050] In formula (8), R 41 and R 42Each independently represents H, C1-C5 alkyl or -R 43 -COOH and R 41 and R 42 At least one of them is -R 43 -COOH, R 43 does not exist or is a C1-C5 alkylene group; when R 41 and R 42 All are -R 43 -COOH, R 41 and R 42 Able to bond into a ring; R 41 ` and R 42 `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 41 and R 42 All are -R 43 -COOH, R 41 and R 42 The 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.

[0051] In the present invention, the ether polycarboxylic acid collapse retaining agent is preferably a random copolymer.

[0052] In the present invention, the number average molecular weight of the ether polycarboxylic acid collapse retaining agent is preferably 5000-80000, such as 5000, 10000, 20000, 30000, 40000, 50000, 60000, 70000, 80000 or any value therebetween.

[0053] The present invention also provides application of the ether polycarboxylic acid collapse preventing agent in the field of construction.

[0054] The present invention will be described in detail below through examples.

[0055] In the following examples and comparative examples, the parts of raw materials are all parts by weight.

[0056] Example 1

[0057] S1, esterification reaction: 4-vinyl-1,2-benzenedicarboxylic acid and PEG-200 were mixed at a molar ratio of 2:1, 3% p-toluenesulfonic acid and 2% p-hydroxyanisole were added, and the mixture was esterified at 90° C. for 3 h under nitrogen protection to obtain esterification functional monomer D1;

[0058] S2, polymerization reaction: 200 parts by mass of vinyl polyethylene glycol ether (having the structure shown in formula (3), wherein R 31 is ethylene, R 32 H, R 33 H, R 34 H, number average molecular weight of 2400) and 100 parts of water were added to a reactor. After stirring and dispersing uniformly, 1 part of hydrogen peroxide was added at once. The mixture was reacted at 25°C for 10 minutes. Then, solution A and solution B were added dropwise. Solution A was 10 parts of a 10% sodium hypophosphite solution. Solution B was a mixed solution consisting of 20 parts of an esterification functional monomer D1, 6 parts of acrylic acid, 6 parts of 4-vinyl-hydroxyethyl benzoate (Compound A), 12 parts of hydroxybutyl methacrylate (Compound B), and 2 parts of thioglycolic acid. Solution A was added dropwise for 150 minutes, and solution B was added dropwise for 150 minutes. After the addition was complete, the reaction was continued for 30 minutes to obtain an ether-based polycarboxylic acid collapse inhibitor BT-1.

[0059] Example 2

[0060] S1. Esterification reaction: 4-vinyl-1,2-benzenedicarboxylic acid and PEG-400 were mixed at a molar ratio of 3:1, 2% stannous oxide and 2% hydroquinone were added, and the mixture was esterified at 80°C for 4 hours under nitrogen protection to obtain esterification functional monomer D2;

[0061] S2, polymerization reaction: 200 parts by mass of methyl vinyl polypropylene glycol ether (having the structure shown in formula (3), wherein R 31 is propylene, R 32 H, R 33 H, R 34 A mixture of 1,2-dimethyl-1,4-dimethoxy-2-propene (1,2-dimethyl-1,4-propene) and 1,2-dimethyl-1,4-dimethoxy-2-propene (1,2-dimethyl-1,4-propene) (with a number average molecular weight of 3,000) and 100 parts of water was added to a reactor. After stirring and dispersing uniformly, 2 parts of ammonium persulfate were added at once. After reacting at 30°C for 10 minutes, solution A and solution B were added dropwise. Solution A was 10 parts of a 5% L-ascorbic acid solution. Solution B was a mixed solution consisting of 20 parts of an esterified functional monomer D2, 5 parts of itaconic acid, 3 parts of 4-propenyl-hydroxypropyl benzoate (compound A), 7 parts of hydroxypropyl methacrylate (compound B), and 4 parts of mercaptoethanol. Solution A was added dropwise for 180 minutes, and solution B was added dropwise for 180 minutes. After the addition was complete, the reaction was continued for 30 minutes to obtain the ether polycarboxylic acid collapse inhibitor BT-2.

[0062] Example 3

[0063] S1. Esterification reaction: 4-vinyl-1,2-benzenedicarboxylic acid and PEG-600 were mixed at a molar ratio of 4:1, 2% dibutyltin oxide and 0.2% phenothiazine were added, and the mixture was esterified at 100° C. for 2 h under nitrogen protection to obtain esterification functional monomer D3;

[0064] S2. Polymerization reaction: Add 200 parts by mass of ethylene glycol monovinyl polyethylene glycol ether (number average molecular weight 4000) and 100 parts by mass of water to a reactor. After stirring and dispersing uniformly, add 3 parts of hydrogen peroxide at once. React at 20°C for 10 minutes, then dropwise add Solution A and Solution B. Solution A is 20 parts of a 10% sodium hypophosphite solution. Solution B is a mixed solution consisting of 5 parts of esterified functional monomer D3, 8 parts of methacrylic acid, 6 parts of 4-methylacryl-hydroxyethyl benzoate (Compound A), 20 parts of hydroxypropyl acrylate (Compound B), and 5 parts of sulfonated mercaptopropionic acid. Add Solution A and Solution B for 160 minutes, and continue the reaction for 30 minutes after the additions are complete. This yields the ether-based polycarboxylic acid collapse inhibitor BT-3.

[0065] Example 4

[0066] S1. Esterification reaction: 4-vinyl-1,2-benzenedicarboxylic acid and PEG-400 were mixed at a molar ratio of 3:1, 1% concentrated sulfuric acid and 0.8% phenothiazine were added, and the mixture was esterified at 90° C. for 3 h under nitrogen protection to obtain esterification functional monomer D4;

[0067] S2. Polymerization reaction: 200 parts by mass of 4-hydroxybutyl vinyl polyethylene glycol ether (number average molecular weight 6000) and 100 parts of water were added to a reactor. After stirring and dispersing uniformly, 5 parts of ammonium persulfate were added at once. The mixture was reacted at 15°C for 10 minutes, and then solution A and solution B were added dropwise. Solution A is 10 parts of a 1% L-ascorbic acid solution. Solution B is a mixed solution consisting of 5 parts of esterification functional monomer D4, 10 parts of maleic acid, 7 parts of 4-butenyl-hydroxybutyl benzoate (Compound A), 15 parts of hydroxyethyl acrylate (Compound B), and 1 part of mercaptopropionic acid. Solution A was added dropwise for 120 minutes, and solution B was added dropwise for 120 minutes. After the addition was complete, the reaction was continued for 30 minutes to obtain the ether polycarboxylic acid collapse inhibitor BT-4.

[0068] Comparative Example 1

[0069] An ether polycarboxylic acid collapse inhibitor was prepared according to the method of Example 1, except that no esterification functional monomer was prepared and added. The remaining conditions were the same as those of Example 1. The specific steps were as follows:

[0070] 200 parts by mass of vinyl polyethylene glycol ether and 100 parts by mass of water were added to a reaction kettle. After stirring and dispersing uniformly, 1 part of hydrogen peroxide was added at once. The mixture was reacted at 25°C for 10 minutes. Solution A and Solution B were then added dropwise. Solution A consisted of 10 parts of a 10% sodium hypophosphite solution. Solution B was a mixed solution consisting of 6 parts of acrylic acid, 6 parts of 4-vinyl-hydroxyethyl benzoate (Compound A), 12 parts of hydroxybutyl methacrylate (Compound B), and 2 parts of thioglycolic acid. Solution A was added dropwise for 150 minutes, and Solution B was added dropwise for 150 minutes. After the addition was complete, the reaction was continued for 30 minutes to obtain the ether polycarboxylic acid collapse inhibitor DBT-1.

[0071] Comparative Example 2

[0072] An ether polycarboxylic acid collapse inhibitor was prepared according to the method of Example 1, except that 4-vinyl-hydroxyethyl benzoate (Compound A) was replaced by hydroxybutyl methacrylate (Compound B) in equal parts by weight. The remaining conditions were the same as those of Example 1. The specific steps were as follows:

[0073] S1, esterification reaction: 4-vinyl-1,2-benzenedicarboxylic acid and PEG-200 were mixed at a molar ratio of 2:1, 3% p-toluenesulfonic acid and 2% p-hydroxyanisole were added, and the mixture was esterified at 90° C. for 3 h under nitrogen protection to obtain esterification functional monomer D1;

[0074] S2. Polymerization Reaction: Add 200 parts by mass of vinyl polyethylene glycol ether and 100 parts by mass of water to a reactor. After stirring and dispersing uniformly, add 1 part of hydrogen peroxide all at once. React at 25°C for 10 minutes, then dropwise add Solution A and Solution B. Solution A is 10 parts of a 10% sodium hypophosphite solution. Solution B is a mixed solution consisting of 20 parts of esterification functional monomer D1, 6 parts of acrylic acid, 18 parts of hydroxybutyl methacrylate (Compound B), and 2 parts of thioglycolic acid. Add Solution A and Solution B dropwise for 150 minutes, and 150 minutes respectively. After the additions are complete, continue the reaction for 30 minutes to obtain the ether polycarboxylic acid collapse inhibitor DBT-2.

[0075] Comparative Example 3

[0076] An ether polycarboxylic acid collapse inhibitor was prepared according to the method of Example 1, except that in the preparation of the esterification functional monomer, 4-vinyl-1,2-phthalic acid was replaced by methacrylic acid in the same molar amount. The remaining conditions were the same as those of Example 1. The specific steps were as follows:

[0077] S1. Esterification reaction: Methacrylic acid and PEG-200 were mixed at a molar ratio of 2:1, 3% p-toluenesulfonic acid and 2% p-hydroxyanisole were added, and the mixture was esterified at 90° C. for 3 h under nitrogen protection to obtain esterification functional monomer D5;

[0078] S2. Polymerization Reaction: Add 200 parts by mass of vinyl polyethylene glycol ether and 100 parts by mass of water to a reactor. After stirring and dispersing uniformly, add 1 part of hydrogen peroxide all at once. React at 25°C for 10 minutes, then dropwise add Solution A and Solution B. Solution A is 10 parts of a 10% sodium hypophosphite solution. Solution B is a mixed solution consisting of 20 parts of esterification functional monomer D5, 6 parts of acrylic acid, 6 parts of 4-vinyl-hydroxyethyl benzoate (Compound A), 12 parts of hydroxybutyl methacrylate (Compound B), and 2 parts of thioglycolic acid. Add Solution A and Solution B dropwise for 150 minutes, and continue the reaction for 30 minutes after the additions are complete to obtain the ether polycarboxylic acid collapse inhibitor DBT-3.

[0079] Comparative Example 4

[0080] An ether polycarboxylic acid collapse inhibitor was prepared according to the method of Example 1, except that 4-vinyl-hydroxyethyl benzoate (Compound A) was replaced by polyethylene glycol dimethacrylate (number average molecular weight of 1332) in equal parts by weight. The remaining conditions were the same as those of Example 1, and the specific steps were as follows:

[0081] S1, esterification reaction: 4-vinyl-1,2-benzenedicarboxylic acid and PEG-200 were mixed at a molar ratio of 2:1, 3% p-toluenesulfonic acid and 2% p-hydroxyanisole were added, and the mixture was esterified at 90° C. for 3 h under nitrogen protection to obtain esterification functional monomer D1;

[0082] S2. Polymerization Reaction: Add 200 parts by mass of vinyl polyethylene glycol ether and 100 parts by mass of water to a reactor. After stirring and dispersing uniformly, add 1 part of hydrogen peroxide all at once. React at 25°C for 10 minutes, then dropwise add Solution A and Solution B. Solution A is 10 parts of a 10% sodium hypophosphite solution. Solution B is a mixed solution consisting of 20 parts of esterification functional monomer D1, 6 parts of acrylic acid, 6 parts of polyethylene glycol dimethacrylate, 12 parts of hydroxybutyl methacrylate (Compound B), and 2 parts of thioglycolic acid. Add Solution A and Solution B dropwise for 150 minutes, and 150 minutes respectively. After the additions are complete, continue the reaction for 30 minutes to obtain the ether polycarboxylic acid collapse inhibitor DBT-4.

[0083] Comparative Example 5

[0084] An ether polycarboxylic acid collapse inhibitor was prepared according to the method of Example 1, except that PEG-200 was replaced by methoxy polyethylene glycol MPEG-200 in the same molar amount during the preparation of the esterification functional monomer. The remaining conditions were the same as those of Example 1. The specific steps were as follows:

[0085] S1. Esterification reaction: 4-vinyl-1,2-benzenedicarboxylic acid and MPEG-200 were mixed at a molar ratio of 2:1, 3% p-toluenesulfonic acid and 2% p-hydroxyanisole were added, and the mixture was esterified at 90° C. for 3 h under nitrogen protection to obtain esterification functional monomer D6;

[0086] S2. Polymerization Reaction: Add 200 parts by mass of vinyl polyethylene glycol ether and 100 parts by mass of water to a reactor. After stirring and dispersing uniformly, add 1 part of hydrogen peroxide all at once. React at 25°C for 10 minutes, then dropwise add Solution A and Solution B. Solution A is 10 parts of a 10% sodium hypophosphite solution. Solution B is a mixed solution consisting of 20 parts of esterification functional monomer D6, 6 parts of acrylic acid, 6 parts of 4-vinyl-hydroxyethyl benzoate (Compound A), 12 parts of hydroxybutyl methacrylate (Compound B), and 2 parts of thioglycolic acid. Add Solution A and Solution B dropwise for 150 minutes, and continue the reaction for 30 minutes after the additions are complete to obtain the ether polycarboxylic acid collapse inhibitor DBT-5.

[0087] Test Example 1

[0088] (1) The fluidity of the polycarboxylic acid slump retaining agent obtained in the above examples and comparative examples at different dosages and water levels was tested in accordance with GB / T 8077-2012, "Test Method for Homogeneity of Concrete Admixtures." In the tests at different 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 slump retaining agent dosage was 2.0%. The results are shown in Table 2.

[0089] Table 1

[0090] Table 2

[0091] It can be seen from the test results in Table 1 and Table 2 that the polycarboxylic acid slump retaining agent provided by the present invention is relatively insensitive to the dosage and water consumption.

[0092] Test Example 2

[0093] 60g of the ether-based polycarboxylic acid slump retaining agent obtained in the above examples and comparative examples were mixed with 140g of PCE (purchased from Kezhijie New Materials Group Co., Ltd., brand name Point-7408) and 800g of water to obtain test samples. The test samples were prepared using Conch Cement, and the initial slump and expansion of the concrete, as well as the slump and expansion over time, and the concrete state were measured according to GB 8076-2008 "Concrete Admixtures". The concrete mix ratio was: cement 230kg / m 3 , fly ash (grade II) 90kg / m 3 , machine-made sand 850kg / m 3 (mud content is 8%), stone (5-31.5) mm) 1050 kg / m 3 , the initial expansion was controlled at 550±10mm, and the results are shown in Table 3.

[0094] Table 3

[0095] As can be seen from the test results in Table 3, the ether polycarboxylic acid slump retaining agent provided by the present invention has a low dosage and a small loss of expansion over time. The polycarboxylic acid slump retaining agent can improve the slump retaining performance of concrete and reduce the slump loss during pumping. It has the advantages of good workability, good wrapping, fast flow rate, and good anti-mud effect. It can improve the pumping efficiency of concrete and improve the workability of concrete, thereby avoiding problems such as large loss of concrete in the later stage leading to pipe blockage.

[0096] 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 preparation method of an ether-based polycarboxylic acid slump-retaining agent, characterized in that, The method includes: S1. Esterify vinyl phthalic acid with polyethylene glycol. The vinyl phthalic acid has the structure shown in formula (1) to obtain an esterified functional monomer; S2. Carry out a radical polymerization reaction on an esterification functional monomer, an unsaturated polyether monomer, an unsaturated carboxylic acid monomer, and a carboxylic acid hydroxy ester monomer. The carboxylic acid hydroxy ester monomer contains compound A shown in formula (2-1) and compound B shown in formula (2-2). The resulting polymerization reaction product is an ether-type polycarboxylic acid slump retaining agent; In formula (2-1), R 21 is H or an alkyl group having 1 to 5 carbon atoms, R 22 is an alkylene group having 0 to 4 carbon atoms, R 23 is an alkylene group having 1 to 5 carbon atoms; In formula (2-2), R 21 is H or an alkyl group having 1 to 5 carbon atoms, and R 23 is an alkylene group having 1 to 5 carbon atoms; In formula (3), R 31 is an alkylene group having 1 to 5 carbon atoms, R 32 , R 33 and R 34 are each independently H, an alkyl group having 1 to 5 carbon atoms or -OH, and n is an integer of 1 to 100.

2. The preparation method of the ether-based polycarboxylic acid slump retaining agent according to claim 1, characterized in that, The way of the radical polymerization reaction includes: S1`. Dissolve an unsaturated polyether monomer and an oxidant in water to obtain a substrate; S2`. Dropwise add solution A and solution B into the substrate respectively for polymerization reaction. Solution A is a reducing agent solution, and solution B is a mixed solution of an esterified functional monomer, an unsaturated carboxylic acid monomer, a carboxylic acid hydroxy ester monomer and a molecular weight regulator. The product obtained after the reaction is an ether-type polycarboxylic acid slump retaining agent.

3. The preparation method of the ether-based polycarboxylic acid slump-retaining agent according to claim 1, characterized in that, The mass ratio of the unsaturated polyether monomer, the unsaturated carboxylic acid monomer, the esterified functional monomer to the carboxylic acid hydroxy ester monomer is 200:(5 - 10):(5 - 20):(10 - 30).

4. The preparation method of the ether-based polycarboxylic acid slump-retaining agent according to claim 1, wherein, In the preparation process of the esterified functional monomer, the molar ratio of vinyl phthalic acid to polyethylene glycol is (2 - 4):1; Preferably, the vinyl phthalic acid is 4-vinyl-1,2-benzenedicarboxylic acid; Preferably, the polyethylene glycol is selected from at least one of PEG-200, PEG-400, PEG-600, PEG-800 and PEG-1000; Preferably, the conditions of the esterification reaction include a temperature of 80°C - 100°C and a time of 1 - 5 h; Preferably, the esterification reaction is carried out in the presence of a catalyst and an inhibitor; Preferably, the catalyst is selected from at least one of concentrated sulfuric acid, p-toluenesulfonic acid, stannous oxide and dibutyltin oxide; Preferably, the dosage of the catalyst accounts for 1% - 3% of the total mass of vinyl phthalic acid and polyethylene glycol; Preferably, the inhibitor is selected from at least one of p-methoxyphenol, hydroquinone and phenothiazine; Preferably, the dosage of the inhibitor accounts for 0.1% - 2% of the total mass of vinyl phthalic acid and polyethylene glycol.

5. The preparation method of the ether polycarboxylic acid slump retaining agent according to claim 1, characterized in that, The unsaturated polyether monomer is selected from at least one of vinyl polyethylene oxide ether, methyl vinyl polypropylene glycol ether, ethylene glycol mono vinyl polyethylene glycol ether and 4-hydroxybutyl vinyl polyethylene glycol ether.

6. The preparation method of the ether polycarboxylate slump retaining agent according to claim 1, characterized in that The unsaturated carboxylic acid monomer has a structure represented by the formula (4): In formula (4), R 41 and R 42 are each independently H, an alkyl group having 1 to 5 carbon atoms, or -R 43 -COOH, and at least one of R 41 and R 42 is -R 43 -COOH, R 43 is an alkylene group having 0 to 5 carbon atoms; when both R 41 and R 42 are -R 43 -COOH, R 41 and R 42 can form a ring by bonding; R 41 ` and R 42 ` are each independently H or an alkyl group having 1 to 5 carbon atoms; Preferably, the unsaturated carboxylic acid monomer is selected from at least one of acrylic acid, methacrylic acid, itaconic acid and maleic acid; 7. The preparation method of the ether polycarboxylate slump retaining agent according to claim 1, characterized in that, The mass ratio of compound A to compound B in the carboxylic acid hydroxy ester monomer is 1:(2 - 4).

8. The preparation method of the ether-based polycarboxylic acid slump-retaining agent according to claim 1, characterized in that, The oxidant is selected from at least one of hydrogen peroxide, ammonium persulfate, potassium persulfate, sodium persulfate, cumene hydroperoxide, benzoyl peroxide and tert-butyl hydroperoxide; Preferably, the reducing agent is selected from at least one of ascorbic acid, 2,2'-azobis(2-methylpropionamidine) dihydrochloride, 1,1'-azobis(cyclohexanecarbonitrile), sodium bisulfite, sodium sulfite, sodium metabisulfite, sodium formaldehyde sulfoxylate, ferrous sulfate heptahydrate, sodium hypophosphite, sodium phosphite and ammonium ferrous sulfate; Preferably, the molecular weight regulator is a thiol compound, more preferably selected from at least one of mercaptoacetic acid, mercaptopropionic acid, mercaptoethanol and mercaptopropanol; Preferably, the dosage of the oxidant is 1% - 5% of the total mass of the unsaturated polyether monomer; Preferably, the dosage of the reducing agent is 0.1% - 2% of the total mass of the unsaturated polyether monomer; Preferably, the dosage of the molecular weight regulator is 1% to 5% of the total mass of the unsaturated polyether monomer; Preferably, the dropping time of the solution A is 120 to 180 min; Preferably, the dropping time of the solution B is 120 to 180 min; Preferably, the conditions of the polymerization reaction include an initial dropping temperature of 15 to 35 °C and a reaction time of 20 to 60 min after the solution is completely dropped.

9. An ether-type polycarboxylic acid slump retaining agent prepared by the method according to any one of claims 1 to 8.

10. The ether-based polycarboxylic acid slump retaining agent according to claim 9, characterized in that, The ether-based polycarboxylate slump retaining agent includes a polyether structural unit, a carboxylic acid structural unit, an esterification functional structural unit, and a carboxylic acid hydroxy ester structural unit; the esterification functional structural unit has a structure shown in at least one of Formula (5-1), Formula (5-2), and Formula (5-3); the carboxylic acid hydroxy ester structural unit has a structure shown in Formula (6-1) and Formula (6-2); the polyether structural unit has a structure shown in Formula (7); the carboxylic acid structural unit has a structure shown in Formula (8); In formulas (5-1) to (5-3), n is an integer from 1 to 100; In formula (6-1), R 21 is H or an alkyl group having 1 to 5 carbon atoms, R 22 is an alkylene group having 0 to 4 carbon atoms, R 23 is an alkylene group having 1 to 5 carbon atoms; In formula (6-2), R 21 is H or an alkyl group having 1 to 5 carbon atoms, and R 23 is an alkylene group having 1 to 5 carbon atoms; In formula (7), R 31 is an alkylene group having 1 to 5 carbon atoms, R 32 , R 33 and R 34 are each independently H, an alkyl group having 1 to 5 carbon atoms or -OH, and n is an integer from 1 to 100; In formula (8), R 41 and R 42 are each independently H, an alkyl group having 1 to 5 carbon atoms, or -R 43 -COOH, and at least one of R 41 and R 42 is -R 43 -COOH. R 43 is absent or is an alkylene group having 1 to 5 carbon atoms. When both R 41 and R 42 are -R 43 -COOH, R 41 and R 42 can form a ring by bonding. R 41 ` and R 42 ` are each independently H or an alkyl group having 1 to 5 carbon atoms.

11. Use of the ether-type polycarboxylic acid slump retaining agent according to claim 9 or 10 in the construction field.

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