Polyoxyalkyl ether containing ester group and rigid benzene ring structure, ether retarding type polycarboxylic acid water reducing agent and preparation method of ether retarding type polycarboxylic acid water reducing agent

Abstract

The invention relates to the technical field of concrete admixtures, in particular to polyoxyalkyl ether containing an ester group and a rigid benzene ring structure, an ether retarding type polycarboxylate superplasticizer and a preparation method thereof. The ether retarding type polycarboxylic acid water reducing agent is formed by polymerizing a comonomer under the action of an initiator, a chain transfer agent and an emulsifier, the comonomer comprises polyoxyalkyl ether, polyoxyalkyl ether containing an ester group and a rigid benzene ring structure, an ester monomer and unsaturated acid. The polycarboxylate superplasticizer provided by the invention can effectively improve the initial dispersing performance and slump retaining performance of concrete, improve the strength of the concrete and reduce the sensitivity of the concrete, and has good long-acting slump retaining effect and anti-mud effect. And the polycarboxylic acid water reducer can be prepared through reaction at normal temperature, the reaction condition is mild, and energy is effectively saved.

Description

Technical Field

[0001] The present application relates to the technical field of concrete admixtures, and in particular to a polyoxyalkyl ether containing an ester group and a rigid benzene ring structure, an ether-based slow-setting polycarboxylic acid water-reducing agent, and a preparation method thereof. Background Art

[0002] As the demand for high-performance concrete in the construction industry continues to increase, traditional water reducers can no longer meet the requirements of modern engineering. Polycarboxylate water reducers have become the preferred high-performance concrete admixture in today's construction industry due to their high water reduction and high slump retention performance. However, some water reducers in the prior art cannot maintain good slump retention performance while providing good water reduction effects. Therefore, it is particularly important to develop a polycarboxylate water reducer with long slump retention that can slowly release carboxyl groups and maintain good concrete construction performance.

[0003] During the synthesis of polycarboxylic acid water-reducing agent, the reactivity of polyether macromonomer determines the reaction temperature of polycarboxylic acid water-reducing agent. 4-carbon and 5-carbon type water-reducing agents (synthesized using 4-carbon or 5-carbon terminal olefin initiators) are the current mainstream polycarboxylic acid water-reducing agents, accounting for a high proportion, but their reaction temperature is as high as 60°C, requiring heating equipment. 2+2 and 2+4 type water-reducing agents are also recognized by the current market due to their short reaction time, excellent water reduction rate and collapse retention performance, but their macromonomer reactivity is high and requires low-temperature equipment. Both have high production costs and do not meet the requirements of energy conservation and environmental protection. It is of great significance to develop a polycarboxylic acid water-reducing agent that can be synthesized at room temperature.

[0004] For example, the Chinese invention patent application with publication number CN 118580021 A discloses a method for synthesizing an isopentanol polyoxyethylene ether water reducer, which requires high temperature preparation and consumes a lot of energy. The Chinese invention patent application with publication number CN118620143A discloses a long-acting collapse-preserving polycarboxylic acid high-performance water reducer and its preparation method, which introduces a comb-type structure but does not present a step-hydrolysis ester group, and its collapse-preserving performance is less stable. Summary of the invention

[0005] In order to solve the shortcomings of the existing polycarboxylic acid water-reducing agent mentioned in the above background technology, the present application provides a polyoxyalkyl ether containing an ester group and a rigid benzene ring structure, and the technical scheme thereof is as follows: The polyoxyalkyl ether containing an ester group and a rigid benzene ring structure provided in the present application has the following structural formula: , Wherein, R1 is an alkylene group having 1 or 2 carbon atoms; N1 is an alkylene oxide group containing an ester group and a rigid benzene ring structure.

[0006] In some embodiments, the structure of N1 is as follows: ,or ; Among them, n is 5 to 25.

[0007] In some embodiments, the polyoxyalkyl ether containing an ester group and a rigid benzene ring structure is prepared by a first ring-opening polymerization reaction of an unsaturated alcohol and an epoxy ester compound under the action of a catalyst; wherein the unsaturated alcohol is diethylene glycol monoallyl ether or diethylene glycol monovinyl ether; the epoxy ester compound is 2,3-epoxypropyl benzoate or 3,3-diphenyl-2,3-epoxypropionic acid methyl ester; the molar ratio of the unsaturated alcohol to the epoxy ester compound is 1:(4-17); the first ring-opening polymerization reaction temperature is 100°C-150°C, the reaction time is 4.5-5h, and the reaction pressure is 0.2Mpa-0.8Mpa.

[0008] The structural formula of 2,3-epoxypropyl benzoate is:

[0009] The structure of methyl 3,3-diphenyl-2,3-epoxypropionate is: .

[0010] The present application also provides an ether type slow-setting polycarboxylic acid water-reducing agent, which is polymerized by comonomers under the action of an initiator, a chain transfer agent, and an emulsifier; the comonomers include polyoxyalkyl ethers, polyoxyalkyl ethers containing ester groups and rigid benzene ring structures, ester monomers, and unsaturated acids; wherein the polyoxyalkyl ether containing ester groups and rigid benzene ring structures adopts the polyoxyalkyl ether containing ester groups and rigid benzene ring structures described above; the structural formula of the ester monomer is as follows: , wherein R2 is an alkylene group having 1 to 5 carbon atoms.

[0011] In some embodiments, the mass ratio of the ester monomer, polyoxyalkyl ether, polyoxyalkyl ether containing an ester group and a rigid benzene ring structure, and unsaturated acid is (2.5-8):100:(5-12):(6-15); the polymerization reaction temperature is 25°C-35°C, and the reaction time is 0.75h-2h.

[0012] In some embodiments, the unsaturated acid is one or more combinations of acrylic acid, methacrylic acid, and maleic acid; the structural formula of the polyoxyalkyl ether is as follows: , Wherein, R3 is an alkylene group having 3 or 4 carbon atoms; R4 is H or CH3; M2 is (A) x (B) y Block polyether chain, (A) x (B)y It represents a repeating unit of polyoxyethylene or polyoxypropylene, x and y represent the repeating number of A and B respectively, x and y are integers of 0 to 100, and 15≤x+y≤180.

[0013] In some embodiments, the M2 is a random copolymer molecular chain polymerized from ethylene oxide and propylene oxide.

[0014] In some embodiments, the polyoxyalkyl ether is prepared by a second ring-opening polymerization reaction of an unsaturated alcohol and an alkylene oxide substance under the action of a catalyst; the unsaturated alcohol is diethylene glycol monoallyl ether or diethylene glycol monovinyl ether; the alkylene oxide substance is ethylene oxide and / or propylene oxide; when the alkylene oxide substance is one of ethylene oxide and propylene oxide, the molar ratio of the unsaturated alcohol to the alkylene oxide substance is 1: (10-100); when the alkylene oxide substance is a mixture of ethylene oxide and propylene oxide, the molar ratio of the unsaturated alcohol to the alkylene oxide substance is 1: (10-200); the second ring-opening polymerization reaction temperature is 80°C-150°C, and the reaction pressure is 0.1Mpa-0.8Mpa.

[0015] In some embodiments, the catalyst is one or a combination of sodium ethoxide, sodium hydride, and potassium hydride.

[0016] In some embodiments, the initiator includes an oxidant and a reducing agent; the oxidant is one or more combinations of ammonium persulfate, hydrogen peroxide, and benzoyl peroxide; the reducing agent is one or more combinations of sodium hypophosphite, tartaric acid, and potassium bisulfite; the chain transfer agent is one or more combinations of 3-mercaptopropionic acid, mercaptopropionic acid, and potassium hypophosphite; the emulsifier is one or more combinations of sorbitan polyoxyethylene ether tetraoleate and stearic acid polyoxyethylene ester; wherein the amount of the oxidant is 2% to 3.5% of the total mass of the polyoxyalkyl ether, the amount of the reducing agent is 0.5% to 2% of the total mass of the polyoxyalkyl ether, the amount of the chain transfer agent is 1% to 2.5% of the total mass of the polyoxyalkyl ether; the amount of the emulsifier is 1 to 2% of the total mass of the polyoxyalkyl ether.

[0017] The present application also provides a method for preparing the ether-based slow-setting polycarboxylate water-reducing agent as described above, which comprises the following preparation steps: mixing the ester monomer, the polyoxyalkyl ether and the polyoxyalkyl ether containing an ester group and a rigid benzene ring structure, adding an initiator solution, a chain transfer agent solution, an emulsifier solution and an unsaturated acid at 25°C to 35°C to carry out a polymerization reaction, and the addition time is 0.75h to 2h; then keeping the temperature for a certain period of time, adjusting the pH, and obtaining the ether-based slow-setting polycarboxylate water-reducing agent.

[0018] Compared with the prior art, this application has the following beneficial effects: The present application provides a novel polyoxyalkyl ether containing an ester group and a rigid benzene ring structure. When the polyoxyalkyl ether is introduced into the polycarboxylate water-reducing agent as a comonomer of the polycarboxylate water-reducing agent, a more three-dimensional adsorption effect is provided due to the introduction of a slow-release group on the side chain thereof. At the same time, the main chain ester group thereof can release a small molecule carboxylic acid, and the small molecule carboxylic acid can enter the mud powder intercalation layer, thereby improving the anti-mud effect of the water-reducing agent, playing a role in improving the long-term slump retention performance, reducing the hydration heat, and improving the later strength of the concrete.

[0019] The novel polyoxyalkyl ether containing an ester group and a rigid benzene ring structure is used to prepare a polycarboxylate water reducer, so that the polycarboxylate water reducer provided in the present application can effectively improve the initial dispersion performance and slump protection performance of concrete, improve the strength of concrete, and reduce the sensitivity of concrete, and has a good long-term slump protection effect and anti-mud effect. In addition, the novel polyoxyalkyl ether containing an ester group and a rigid benzene ring structure is used to prepare a polycarboxylate water reducer, which can react at room temperature, has mild reaction conditions, and effectively saves energy. DETAILED DESCRIPTION

[0020] In order to make the purpose, technical solutions and advantages of the embodiments of the present application clearer, the technical solutions in the embodiments of the present application will be described clearly and completely below. Obviously, the described embodiments are part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of this application.

[0021] The present application also provides the following embodiments and comparative examples: Example 1 (1) Preparation of polyoxyalkyl ethers containing ester groups and rigid benzene ring structures: In a 1.5L stainless steel high-pressure reactor, add 32.9 parts of diethylene glycol monoallyl ether and 1.4 parts of sodium ethoxide by weight and stir evenly; evacuate the reactor to -0.1Mpa and replace with N2 three times. Heat the reactor to 80°C, and continuously add 160.3 parts of 2,3-epoxypropyl benzoate to the reactor. Control the reaction temperature to 100°C and the reaction pressure to 0.6Mpa. The reaction time is 5h. After the product is cooled, add a neutralizer and collect the product; (2) Preparation of polyoxyalkyl ethers: In a 1.5L stainless steel high-pressure reactor, add 58.6 parts of diethylene glycol monovinyl ether and 1 part of sodium hydroxide by weight and stir evenly; evacuate the reactor to -0.1Mpa and replace with N2 three times. Heat the reactor to 80°C, continuously add 990 parts of ethylene oxide to the reactor, control the reaction temperature to 120°C, and the reaction pressure to 0.3Mpa. Stop the reaction when the pressure in the reactor no longer decreases. After the product is cooled, add a neutralizer and collect the product; (3) Copolymerization reaction: First, by weight, 5 parts of diethyl 2-(4-pentene)malonate, 5 parts of polyoxyalkylene polyether with an ester structure, 100 parts of polyoxyalkylene polyether, 1.9 parts of sodium hypophosphite, 1 part of sorbitan polyoxyethylene ether tetraoleate and 59.26 parts of water are added into a first reaction container and stirred evenly; 2 parts of ammonium persulfate and 20 parts of water are mixed evenly in the first dropping device; 2 parts of 3-mercaptopropionic acid and 20 parts of water are mixed evenly in the second dropping device; 6 parts of acrylic acid and 20 parts of water are mixed evenly in the third dropping device; At room temperature of 25°C to 35°C, the materials in the first dropping device, the second dropping device and the third dropping device are sequentially added dropwise to the first reaction container, and the materials in the third dropping device, the second dropping device and the first dropping device are added dropwise within 45 minutes, and the temperature is kept constant for 30 minutes; (4) 12 parts by weight of 32% sodium hydroxide were added to obtain the ether-based slow-setting polycarboxylic acid water-reducing agent with a concentration of 50%.

[0022] Example 2 (1) Preparation of polyoxyalkyl ethers containing ester groups and rigid benzene ring structures: In a 1.5L stainless steel high-pressure reactor, add 115.64 parts of diethylene glycol monovinyl ether and 0.8 parts of sodium hydride by weight and stir evenly; evacuate the reactor to -0.1Mpa and replace it with N2 three times. Heat the reactor to 130°C, and continuously add 1779.9 parts of 3,3-diphenyl-2,3-epoxypropionic acid methyl ester to the reactor, control the reaction temperature to 150°C, and the reaction pressure to 0.2Mpa. The reaction time is 4.5h. After the product is cooled, add a neutralizer and collect the product; (2) Preparation of polyoxyalkyl ethers: In a 1.5L stainless steel high-pressure reactor, add 20.5 parts of diethylene glycol monoallyl ether and 1.5 parts of sodium ethoxide by weight and stir evenly; evacuate the reactor to -0.1Mpa and replace with N2 three times. Heat the reactor to 80°C, continuously add 814.5 parts of propylene oxide to the reactor, control the reaction temperature to 110°C, and the reaction pressure to 0.5Mpa. Stop the reaction when the pressure in the reactor no longer decreases. After the product is cooled, add a neutralizer and collect the product; (3) Copolymerization reaction: by weight, first 7 parts of 2- (4-propylene) diethyl malonate, 7 parts of polyoxyalkylene polyether with an ester structure, 100 parts of polyoxyalkylene polyether, 2 parts of polyoxyethylene stearate and 70 parts of water, added to the first reaction vessel and stirred; 2.5 parts of hydrogen peroxide and 20 parts of water are uniformly mixed in the first dropping device; 0.6 parts of tartaric acid, 1.5 parts of mercaptopropionic acid and 20 parts of water are uniformly mixed in the second dropping device; 13 parts of methacrylic acid and 20 parts of water are uniformly mixed in the third dropping device; At room temperature of 25°C to 35°C, the materials in the first dropping device, the second dropping device and the third dropping device are sequentially added dropwise to the first reaction container, and the materials in the third dropping device, the second dropping device and the first dropping device are added dropwise within 65 minutes, and the reaction is carried out at a constant temperature for 30 minutes; (4) 12 parts by weight of 32% sodium hydroxide were added to obtain the ether-based slow-setting polycarboxylic acid water-reducing agent with a concentration of 50%.

[0023] Example 3 (1) Preparation of polyoxyalkyl ethers containing ester groups and rigid benzene ring structures: In a 1.5L stainless steel high-pressure reactor, add 35.7 parts of diethylene glycol monovinyl ether and 2 parts of potassium hydride (compared with metallic potassium, the use of potassium hydride improves the production safety factor) by weight, and stir evenly; evacuate the reactor to -0.1Mpa and replace it with N2 three times. Heat the reactor to 100°C, and continuously add 817.9 parts of 2,3-epoxypropyl benzoate to the reactor, control the reaction temperature to 120°C, and the reaction pressure to 0.4Mpa. The reaction time is 5h. After the product is cooled, add a neutralizer and collect the product; (2) Preparation of polyoxyalkyl ethers: In a 1.5L stainless steel high-pressure reactor, add 42.9 parts of diethylene glycol monoallyl ether and 1.3 parts of potassium metal by weight and stir evenly; evacuate the reactor to -0.1Mpa and replace with N2 three times. Heat the reactor to 80°C, and continuously add 487.4 parts of ethylene oxide and 642.5 parts of propylene oxide to the reactor. Control the reaction temperature to 120°C and the reaction pressure to 0.6Mpa. Stop the reaction when the pressure in the reactor no longer decreases. After the product is cooled, add a neutralizer and collect the product; (3) Copolymerization reaction: by weight, 3 parts of diethyl 2-(4-pentene)malonate, 12 parts of polyoxyalkylene polyether with an ester structure, 100 parts of polyoxyalkylene polyether, 3.2 parts of potassium bisulfite solution, 1.5 parts of sorbitan polyoxyethylene ether tetraoleate and 67.6 parts of water were added to a first reaction vessel and stirred uniformly; 3.5 parts of benzoyl peroxide and 20 parts of water are mixed evenly in the first dropping device; 1 part of potassium hypophosphite and 20 parts of water are mixed evenly in the second dropping device; 9 parts of maleic acid and 20 parts of water are mixed evenly in the third dropping device; At room temperature of 25°C to 35°C, the materials in the first dropping device, the second dropping device and the third dropping device are sequentially added dropwise to the first reaction container, and the materials in the third dropping device, the second dropping device and the first dropping device are added dropwise within 95 minutes, and the reaction is carried out at a constant temperature for 30 minutes; (4) 12 parts by weight of 32% sodium hydroxide were added to obtain the ether-based slow-setting polycarboxylic acid water-reducing agent with a concentration of 50%.

[0024] Comparative Example 1 (using 4-hydroxybutyl vinyl ether equimolar replacement) The only difference from Example 1 is that in the preparation process of the polyoxyalkyl ether containing an ester group and a rigid benzene ring structure in step (1), 4-hydroxybutyl vinyl ether is used in an equal molar amount to replace diethylene glycol monoallyl ether, and in the preparation process of the polyoxyalkyl ether in step (2), 4-hydroxybutyl vinyl ether is used in an equal molar amount to replace diethylene glycol monovinyl ether.

[0025] Comparative Example 2 (using ethylene glycol monovinyl ether to replace diethylene glycol monovinyl ether in equal moles) The only difference from Example 1 is that in the preparation process of the polyoxyalkyl ether containing an ester group and a rigid benzene ring structure in step (1), ethylene glycol monovinyl ether is used in an equal molar amount to replace diethylene glycol monoallyl ether, and in the preparation process of the polyoxyalkyl ether in step (2), ethylene glycol monovinyl ether is used in an equal molar amount to replace diethylene glycol monovinyl ether. The other steps and conditions are the same as those in Example 1. The other steps and conditions are the same as those in Example 1.

[0026] Comparative Example 3 (using 5-carbon polyether to replace polyoxyalkylene polyether in equal moles) The only difference from Example 1 is that in step (2), no polyoxyalkyl ether is prepared, and in step (3), 5-carbon polyether is directly used in an equal molar amount to replace the polyoxyalkylene polyether in Example 1. The other steps and conditions are the same as those in Example 1.

[0027] Among them, the specific 5-carbon polyether is isopentenyl polyethylene glycol ether, and its structural formula is CH2=CH(CH3)CH2CH2O(CH2CH2O) n H where n=44 and the molecular weight is 2023.

[0028] Comparative Example 4 (without addition of polyoxyalkyl ether with ester group) The only difference from Example 1 is that the polyoxyalkyl ether containing an ester group and a rigid benzene ring structure is not added in the copolymerization reaction of step (3). The other steps and conditions are the same as those of Example 1.

[0029] Comparative Example 5 The commercially available Point-TS8 polycarboxylate water-reducing agent mother liquor and white sugar were selected and mixed in amounts of 0.2% and 0.04% of the cementitious material respectively for concrete verification.

[0030] Comparative Example 6 (without adding ester monomer) The only difference from Example 1 is that no ester monomer is added to the copolymerization reaction in step (3). The other steps and conditions are the same as those in Example 1.

[0031] Comparative Example 7 (Hydroxyethyl methacrylate replaces diethyl 2-(4-pentene)malonate) The only difference from Example 1 is that in the copolymerization reaction of step (3), hydroxyethyl acrylate is used in place of diethyl 2-(4-pentene)malonate. The other steps and conditions are the same as those of Example 1.

[0032] Comparative Example 8 (Methyl 2,3-epoxypropionate substituted for 2,3-epoxypropyl benzoate) The only difference from Example 1 is that in step (1), 2,3-epoxypropionic acid methyl ester is used to replace 2,3-epoxypropyl benzoate in an equal molar amount. The other steps and conditions are the same as those in Example 1.

[0033] Comparative Example 9 (Methyl 6-heptenoate equimolarly replaces diethyl 2-(4-pentene)malonate) The only difference from Example 1 is that in the copolymerization reaction of step (3), methyl 6-heptenoate is used in place of diethyl 2-(4-pentene)malonate. The other steps and conditions are the same as those of Example 1.

[0034] Performance tests of the products of the embodiments and comparative examples: The polycarboxylic acid water-reducing agent synthesized in Examples 1 to 3 was compared with the machine-made sand concrete obtained in Comparative Examples 1 to 9: Conch PO42.5R cement was used, the water-reducing agent dosage in Examples 1 to 3 was 0.2% (solid content) of the cementitious material, the water-reducing agent dosage in Comparative Examples 1 to 4 and Comparative Examples 6 to 9 was 0.2% (solid content) of the cementitious material, and the dosage of the admixture in Comparative Example 5 referred to the specific compound formula.

[0035] According to GB 8076-2008 "Concrete Admixtures", the slump and expansion are measured. The concrete standard mix ratio is: cement 285 kg / m 3 、Fly ash 63 kg / m 3 、Mineral powder 60 kg / m 3 , machine-made sand 825 kg / m 3 、Stone 1013 kg / m 3 , wherein no admixture is added to the benchmark, and Examples 1 to 3 and Comparative Examples 1 to 9 are tested using the benchmark mix ratio, and the concrete test results are shown in Table 1: Table 1

[0036] From the results in Table 1, we can see that: The performance of the embodiments is better than the benchmark and the comparative example. Combining the results of Examples 1-3, it can be seen that after adding the product of the present application, the initial dispersion performance and slump protection performance of the concrete can be effectively improved, the concrete strength can be improved, and the sensitivity of the concrete can be reduced, especially the slump and expansion loss values ​​of the concrete in 4 hours, which are better maintained in Examples 1-3. It can be seen that the product of the present application has a more obvious long-term slump protection effect.

[0037] It can be seen from Example 1 and Comparative Examples 1-2 that the present application uses a specific structural unsaturated alcohol, which has a significant improvement in the initial water-reducing performance of concrete compared to the comparative example of using 4-hydroxybutyl vinyl ether and ethylene glycol monovinyl ether as initiators to prepare polyether macromonomers.

[0038] It can be seen from Example 1 and Comparative Examples 1-2 that the present application uses a specific structural unsaturated alcohol, which has a significant improvement in the 1h and 2h collapse retention performance of concrete compared to the use of 4-hydroxybutyl vinyl ether and ethylene glycol monovinyl ether as initiators to prepare polyether monomers with ester groups.

[0039] It can be seen from Example 1 and Comparative Example 3 that the polyoxyalkyl ether prepared in the present application has greatly improved 4h slump retention performance compared with the polycarboxylic acid water reducer prepared by copolymerization using 5-carbon polyether.

[0040] It can be seen from Example 1 and Comparative Example 4 that when the polyether monomer with an ester group is not used to participate in the polymerization, the collapse resistance of the concrete decreases and the concrete strength also decreases slightly.

[0041] It can be seen from Example 1 and Comparative Example 5 that, compared with the existing method of compounding a water-reducing agent with a retarder, the concrete water-reducing agent prepared by the polyether macromonomer, the polyether monomer with an ester group and the introduction of an ester monomer provided in the present application not only has better water-reducing performance, but also greatly improves the slump retention performance, while also improving the early strength of the concrete.

[0042] It can be seen from Example 1 and Comparative Examples 6 and 7 that, compared with not adding ester monomers or using other types of existing ester monomers, the specific structure ester monomers used in this application have better collapse protection performance and improve the strength of concrete. At the same time, it has a better anti-mud effect on machine-made sand with a high stone powder content, which is manifested as the present application still has flowability after 2 hours, while the other two have no flowability.

[0043] It can be seen from Example 1 and Comparative Example 8 that the adsorption groups of the water reducer of Comparative Example 8 after hydrolysis are easily buried by other long side chain groups, resulting in reduced adsorption capacity, so that the slump at 2h and 4h is less than that of Example 1.

[0044] It can be seen from Example 1 and Comparative Example 9 that the collapse-preserving effect of the water-reducing agent of Comparative Example 9 decreases at 2h and 4h, and the number of adsorption groups after hydrolysis is less than that of Example 1, resulting in an insignificant collapse-preserving effect.

[0045] The polyoxyalkyl ether containing an ester group and a rigid benzene ring structure, the ether-based slow-setting polycarboxylate water-reducing agent and the preparation method thereof provided in the present application at least include the following design concepts, action mechanisms and beneficial effects: 1. This application uses unsaturated alcohol diethylene glycol monovinyl ether (carbon structure is 2+2+2) and diethylene glycol monoallyl ether (carbon structure is 3+2+2) to polymerize with 2,3-epoxypropyl benzoate and 3,3-diphenyl-2,3-epoxypropionic acid methyl ester to prepare polyether products. The structure of the polyether product with ester group is as follows: , Among them, R1 is an alkylene group having 1 or 2 carbon atoms; the structure of N1 is. ,or ; Wherein, n is 5 to 25.

[0046] From the above structure, it can be seen that the polyether product introduces multiple ester groups, so a large number of carboxyl groups can be introduced after hydrolysis, which are adsorbed on the surface of cement particles to delay the dissolution of cement particles. In addition, the chain segments and free calcium ions in the pore solution form complex compounds to delay the formation of supersaturated solution in the solution. At the same time, ester groups with different hydrolysis rates are introduced, and calcium hydroxide precipitates and ettringite precipitates can also be adsorbed in the pore solution.

[0047] At the same time, the benzene ring on the ester group (in the N1 group) increases the rigidity of the chain segment, and after the ester group is hydrolyzed, the benzene ring or the double benzene ring remains on the side chain structure, increasing the steric hindrance effect of the chain segment, making it less likely for the hydration product to aggregate, further prolonging the hydration time and improving the retarding effect. At the same time, it can also reduce the hydrolysis rate of the ester group, which is conducive to establishing different hydrolysis rates of the ester group in the overall polycarboxylate water reducer. If the structure of the polyether monomer (especially the ester group) does not have a corresponding benzene ring, for example, the structure of N1 adopts the structure without a benzene ring as shown below:

[0048] This will result in the carboxyl group of the adsorption group after hydrolysis having no rigid chain segment support and will be "buried" in other side chains. Due to the shielding effect of other long flexible side chains, its adsorption capacity will be further reduced.

[0049] 2. From the structure of the polyoxyalkyl ether containing an ester group and a rigid benzene ring structure, it can be seen that among the polyoxyalkyl ether containing an ester group and a rigid benzene ring structure provided in the present application, the unsaturated alcohol preferably adopts a terminal olefin initiator (diethylene glycol monoallyl ether or diethylene glycol monovinyl ether) of a 2+2+2, 3+2+2 carbon structure. Compared with the initiator with low reactivity for synthesizing 2+2 or 2+4 type water reducers, the present application does not need to react under low temperature conditions, but can react at room temperature, which plays a role in energy conservation and environmental protection, and caters to the effect of dual carbon emission reduction. Compared with 4-carbon and 5-carbon polycarboxylic acid water reducers, heating is not required for reaction, which also saves energy.

[0050] Although 1-allyloxypropan-1-ol (carbon structure is 3+3) or 4-(allyloxy)-1-butanol (carbon structure is 3+4) is used as the unsaturated alcohol, terminal olefin initiators with 3+3 carbon structure or 3+4 carbon structure can also be polymerized at room temperature to obtain polyoxyalkyl ethers containing ester groups and rigid benzene ring structures.

[0051] However, different structures of terminal olefin initiators affect the structure of the final polyoxyalkyl ether containing an ester group and a rigid benzene ring structure. From the structure of the polyoxyalkyl ether containing an ester group and a rigid benzene ring structure, it can be seen that compared with the use of 1-allyloxyprop-1-ol (carbon structure is 3+3) or 4-(allyloxy)-1-butanol (carbon structure is 3+4) as a terminal olefin initiator, the present application uses diethylene glycol monoallyl ether or diethylene glycol monovinyl ether, that is, 3+2+2 or 2+2+2 structured unsaturated alcohols as terminal olefin initiators, which brings more folding angles to the side chain structure of the polycarboxylate water-reducing agent in the pore solution, improves the segment flexibility of the polycarboxylate water-reducing agent, makes it easier to adsorb active sites of cement particles and hydration products, and further improves the subsequent slump retention performance. At the same time, diethylene glycol monoallyl ether or diethylene glycol monovinyl ether has high activity, which shortens the reaction time of the copolymerization reaction and increases the solid content of the final polycarboxylic acid water-reducing agent product, so that industrial production improves production efficiency and saves energy, thereby saving energy and improving synthesis efficiency for subsequent industrial applications.

[0052] 3. This application introduces diester groups on the main chain of polycarboxylic acid water-reducing agent through ester monomers (the specific ester monomers involved in the polymerization are an olefin-coordinated diester structure). After hydration to an alkaline environment, more carboxyl groups can be released, which is beneficial to the adsorption of polycarboxylic acid chain segments and improves the slow setting and slump-preserving effects. At the same time, under the alkaline conditions of cement, effective adsorption prevents excessive consumption of free water content in the pore solution of polycarboxylic acid water-reducing agent, further improves the steric hindrance effect of polyether segments and rigid benzene ring structures, and plays a role in continuously maintaining slump. When the ester group is hydrolyzed, carboxylate radicals are released, which adsorb calcium ions and the surface of cement particles or hydration products, further reduce the calcium ion concentration of the solution, cover the nucleation sites of the hydration products, prolong the nucleation time of the hydration products, inhibit the growth of Ca(OH)2 and AFt nuclei, slow down the hydration rate, and prolong the cement hydration induction period, thereby improving the dispersion retention and having an excellent slump-preserving effect. At the same time, the products released after hydrolysis still carry a large number of carboxyl groups, which can be freely dispersed in the negatively charged areas of cement particles or complexed with calcium ions, further filling the nucleation sites of hydration products and further hindering the generation of hydration products.

[0053] In addition, the structure of ester monomers affects the molecular structure of water reducers. If the proportion of olefin and ester groups in ester monomers is different, the structure of polycarboxylic acid water reducers will be different, thus affecting the effect of water reducers. Although some existing ester monomers involved in polymerization also have ester groups, and even have diester structures. However, their structures are one olefin combined with one ester group or dienes combined with diester groups. For example, the structure of ester monomers is as follows: ; Compared with the existing ester monomers in which the ratio of olefin to ester group is 1 (one olefin with one ester group or two olefins with two ester groups), the present application adopts a specific ester monomer (one olefin with two ester groups, the structure is shown below). The combination of monoolefin and two ester groups will not cause the polycarboxylate water reducer to produce a cross-linking reaction. Its two ester group structures produce more carboxyl groups when hydrolyzed, which are easier to adsorb on the surface of cement particles and hydration products, thereby improving the collapse-preserving effect.

[0054] .

[0055] 4. The process of this application is simple to operate, the reaction conditions are mild, it is easy to scale up production, the production process is safe and pollution-free, and it is an environmentally friendly product.

[0056] Finally, it should be noted that: The specific parameters or some commonly used reagents or raw materials in the above embodiments are specific embodiments or preferred embodiments of the present application, but are not intended to limit the present application. Those skilled in the art may make adaptive adjustments within the scope of the present application.

[0057] The above embodiments are only used to illustrate the technical solutions of the present application, rather than to limit them. Although the present application has been described in detail with reference to the aforementioned embodiments, a person skilled in the art should understand that the technical solutions described in the aforementioned embodiments may still be modified, or some or all of the technical features thereof may be replaced by equivalents. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the scope of the technical solutions of the embodiments of the present application.

Claims

1. A polyoxyalkyl ether containing an ester group and a rigid benzene ring structure, characterized in that: Its structural formula is as follows: ， Wherein, R1 is an alkylene group having 1 or 2 carbon atoms; N1 is an alkylene oxide group containing an ester group and a rigid benzene ring structure.

2. The polyoxyalkyl ether containing an ester group and a rigid benzene ring structure according to claim 1, characterized in that: The structure of N1 is as follows: ,or ; Among them, n is 5 to 25.

3. The polyoxyalkyl ether containing an ester group and a rigid benzene ring structure according to claim 1, characterized in that: It is prepared by a first ring-opening polymerization reaction of an unsaturated alcohol and an epoxy acid ester compound under the action of a catalyst; Wherein, the unsaturated alcohol is diethylene glycol monoallyl ether or diethylene glycol monovinyl ether; the epoxy ester compound is 2,3-epoxypropyl benzoate or 3,3-diphenyl-2,3-epoxypropionic acid methyl ester; The molar ratio of the unsaturated alcohol to the epoxy ester compound is 1:(4-17); the first ring-opening polymerization reaction temperature is 100° C.-150° C., the reaction time is 4.5-5 hours, and the reaction pressure is 0.2Mpa-0.8Mpa.

4. An ether-based slow-setting polycarboxylate water-reducing agent, characterized in that: The copolymer is formed by polymerization of comonomers under the action of an initiator, a chain transfer agent and an emulsifier; the comonomers include polyoxyalkyl ethers, polyoxyalkyl ethers containing ester groups and rigid benzene ring structures, ester monomers and unsaturated acids; Wherein, the polyoxyalkyl ether containing an ester group and a rigid benzene ring structure is the polyoxyalkyl ether containing an ester group and a rigid benzene ring structure as claimed in any one of claims 1 to 3; The structural formula of the ester monomer is as follows: , wherein R2 is an alkylene group having 1 to 5 carbon atoms.

5. The ether slow-setting polycarboxylate water-reducing agent according to claim 4, characterized in that: The mass ratio of the ester monomer, the polyoxyalkyl ether, the polyoxyalkyl ether containing an ester group and a rigid benzene ring structure, and the unsaturated acid is (2.5-8):100:(5-12):(6-15); The polymerization reaction temperature is 25° C. to 35° C., and the reaction time is 0.75 h to 2 h.

6. The ether slow-setting polycarboxylate water-reducing agent according to claim 4, characterized in that: The unsaturated acid is one or more combinations of acrylic acid, methacrylic acid and maleic acid; The structural formula of the polyoxyalkyl ether is as follows: ， Wherein, R3 is an alkylene group having 3 or 4 carbon atoms; R4 is H or CH3; M2 is (A) x (B) y Block polyether chain, (A) x (B) y It represents a repeating unit of polyoxyethylene or polyoxypropylene, x and y represent the repeating number of A and B respectively, x and y are integers of 0 to 100, and 15≤x+y≤180.

7. The ether slow-setting polycarboxylate water-reducing agent according to claim 6, characterized in that: The M2 is a random copolymer molecular chain formed by polymerization of ethylene oxide and propylene oxide.

8. The ether slow-setting polycarboxylate water-reducing agent according to claim 6, characterized in that: The polyoxyalkyl ether is prepared by a second ring-opening polymerization reaction of an unsaturated alcohol and an alkylene oxide substance under the action of a catalyst; The unsaturated alcohol is diethylene glycol monoallyl ether or diethylene glycol monovinyl ether; the alkylene oxide substance is ethylene oxide and / or propylene oxide; When the alkylene oxide substance is one of ethylene oxide and propylene oxide, the molar ratio of the unsaturated alcohol to the alkylene oxide substance is 1: (10-100); when the alkylene oxide substance is a mixture of ethylene oxide and propylene oxide, the molar ratio of the unsaturated alcohol to the alkylene oxide substance is 1: (10-200); the second ring-opening polymerization reaction temperature is 80°C-150°C, and the reaction pressure is 0.1Mpa-0.8Mpa.

9. The ether slow-setting polycarboxylate water-reducing agent according to claim 4, characterized in that: The initiator includes an oxidizing agent and a reducing agent; The oxidant is one or more combinations of ammonium persulfate, hydrogen peroxide, and benzoyl peroxide; The reducing agent is one or more combinations of sodium hypophosphite, tartaric acid, and potassium bisulfite; The chain transfer agent is one or more combinations of 3-mercaptopropionic acid, mercaptopropionic acid, and potassium hypophosphite; The emulsifier is one or more combinations of sorbitol polyoxyethylene ether tetraoleate and stearic acid polyoxyethylene ester; Among them, the amount of the oxidant is 2% to 3.5% of the total mass of the polyoxyalkyl ether, the amount of the reducing agent is 0.5% to 2% of the total mass of the polyoxyalkyl ether, the amount of the chain transfer agent is 1% to 2.5% of the total mass of the polyoxyalkyl ether; and the amount of the emulsifier is 1 to 2% of the total mass of the polyoxyalkyl ether.

10. A method for preparing the ether slow-setting polycarboxylate water-reducing agent according to any one of claims 4 to 9, characterized in that: The method comprises the following preparation steps: The ester monomer, the polyoxyalkyl ether and the polyoxyalkyl ether containing an ester group and a rigid benzene ring structure are mixed, and an initiator solution, a chain transfer agent solution, an emulsifier solution and an unsaturated acid are added at 25° C. to 35° C. to carry out a polymerization reaction, and the addition time is 0.75 h to 2 h; Then, the temperature is kept at a certain time, and the pH is adjusted to obtain the ether type slow-setting polycarboxylate water-reducing agent.

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