A Retarding Polycarboxylate Superplasticizer and Its Preparation Method

Abstract

The present application discloses a retarding polycarboxylate water reducer and a preparation method thereof, relating to the field of concrete admixtures. The retarding polycarboxylate water reducer comprises 45 - 55 parts of unsaturated polyether monomer, 15 - 20 parts of quaternary ammonium salt cationic monomer, 10 - 15 parts of unsaturated sulfonic acid or unsaturated sulfonate monomer, 5.5 - 7.5 parts of unsaturated phosphate monomer, 4.8 - 6.2 parts of unsaturated hydroxy fatty acid ester monomer, 100 - 120 parts of acrylic acid, 1 - 2 parts of chain transfer agent, 1.5 - 2 parts of oxidant, 0.75 - 1 part of reducing agent and 500 parts of water. The structural general formula of the unsaturated polyether monomer is R1CH2O(CH2CH2O) n R2, where R1 is an alkenyl group and R2 is any one of a phenyl group and a phenylalanine alkyl ester group. The retarding polycarboxylate water reducer of the present application can effectively improve the retarding effect of the concrete mixture with a fine aggregate mud content greater than 1.5% in a high-temperature environment and ensure workability.

Description

Technical Field

[0001] This application relates to the field of concrete admixtures, and in particular to a retarding polycarboxylate water reducer and a preparation method thereof. Background Art

[0002] For concrete mixtures that need to be used in high-temperature seasons or require long-term transportation and pumping, good retarding performance is usually required to ensure the convenience of construction.

[0003] Currently, the methods to improve the retarding performance of concrete include adding inorganic retarders or polycarboxylate water reducers with retarding effects. Common inorganic retarders include phosphates, sulfates, borates, etc. However, these inorganic retarders have problems such as large dosage and poor retarding effect. Common polycarboxylate water reducers are usually prepared from unsaturated polyether monomers, unsaturated phosphate esters, unsaturated fatty acids, and unsaturated sulfonic acids or sulfonates, which can achieve retarding performance to a certain extent. However, they are easily affected by the mud content of fine aggregates and environmental temperature. For example, when the mud content of fine aggregates is higher than 1.5% and the environmental temperature is greater than 35°C, the retarding effect of the concrete mixture becomes poor, the dosage of the polycarboxylate water reducer increases, and the cost also increases accordingly. Summary of the Invention

[0004] In order to improve the poor retarding property of polycarboxylate water reducers for concrete admixtures with high mud content of fine aggregates in high-temperature environments in related technologies, this application provides a retarding polycarboxylate water reducer and a preparation method thereof.

[0005] In a first aspect, a retarding polycarboxylate water reducer provided by this application adopts the following technical solution:

[0006] A retarding polycarboxylate water reducer, comprising 45 - 55 parts by weight of an unsaturated polyether monomer, 15 - 20 parts by weight of a quaternary ammonium salt cationic monomer, 10 - 15 parts by weight of an unsaturated sulfonic acid or unsaturated sulfonate monomer, 5.5 - 7.5 parts by weight of an unsaturated phosphate ester monomer, 4.8 - 6.2 parts by weight of an unsaturated hydroxy fatty acid ester monomer, 100 - 120 parts by weight of acrylic acid, 1 - 2 parts by weight of a chain transfer agent, 1.5 - 2 parts by weight of an oxidizing agent, 0.75 - 1 part by weight of a reducing agent, and 500 parts by weight of water. The structural general formula of the unsaturated polyether monomer is R1CH2O(CH2CH2O) n R2, wherein R1 is an alkenyl group, and R2 is any one of a phenyl group and a phenylalanine alkyl ester group.

[0007] The retarding polycarboxylate water reducer of the present application is obtained by reacting an unsaturated polyether monomer with a specific structure with a quaternary ammonium salt cationic monomer, an unsaturated sulfonic acid or an unsaturated sulfonate monomer, an unsaturated phosphate ester monomer, an unsaturated hydroxy fatty acid ester monomer, acrylic acid, etc. through a specific ratio. Among them, the shrinkage-reducing polycarboxylate water reducer has low sensitivity to mud in aggregates, has anti-mud property, can be evenly dispersed in a concrete mixture with a high mud content in fine aggregates (more than 1.5%), and stably adsorbs on the surface of cement particles to form a water film. The water film has good thermal stability and can prevent the problem that water easily accelerates the penetration of water into cement in a high-temperature environment (>35°C), thereby delaying the hydration rate of cement in a high-temperature environment and effectively improving the retarding effect of the retarding polycarboxylate water reducer on a concrete mixture with a mud content in fine aggregates greater than 1.5% in a high-temperature environment.

[0008] In some specific embodiments, the unsaturated polyether monomer includes a first unsaturated polyether monomer and a second unsaturated polyether monomer. In the first unsaturated polyether monomer, R2 is a phenyl group; in the second unsaturated polyether monomer, R2 is a phenylalanine alkyl ester group, and the weight ratio of the first unsaturated polyether monomer to the second unsaturated polyether monomer is (1 - 1.5):1.

[0009] In the present application, the unsaturated polyether monomer preferably is a composition with a specific ratio of the first unsaturated polyether monomer and the second unsaturated polyether monomer. Among them, R2 in the first unsaturated polyether monomer is a phenyl group, and R2 in the second unsaturated polyether monomer is a phenylalanine alkyl ester group, which is beneficial to further improving the anti-mud property of the retarding polycarboxylate water reducer and can further extend the initial setting time of concrete with a high mud content in fine aggregates in a high-temperature environment.

[0010] In some specific embodiments, in the unsaturated polyether monomer, the value of n is 15 - 20.

[0011] In the present application, the value of n in the general formula of the unsaturated polyether monomer is preferably 15 - 20, which is beneficial to further improving the dispersibility of the retarding polycarboxylate water reducer. Under other unchanged conditions, it can further extend the initial setting time of concrete with a high mud content in fine aggregates in a high-temperature environment.

[0012] In some specific embodiments, the quaternary ammonium salt cationic monomer adopts at least one of dimethyldiallylammonium chloride, methacryloyloxyethyltrimethylammonium chloride, and methacryloyloxyethyldimethylbenzylammonium chloride.

[0013] In some specific embodiments, the quaternary ammonium salt cationic monomer adopts a composition of methacryloyloxyethyltrimethylammonium chloride and methacryloyloxyethyldimethylbenzylammonium chloride, and the weight ratio of methacryloyloxyethyltrimethylammonium chloride to methacryloyloxyethyldimethylbenzylammonium chloride is 1:(3 - 4).

[0014] In this application, the quaternary ammonium salt cationic monomer is preferably a composition of methacryloyloxyethyl trimethyl ammonium chloride and methacryloyloxyethyl dimethyl benzyl ammonium chloride with a weight ratio of 1:(3 - 4), which is beneficial to further improving the anti-sludge property of the retarding polycarboxylate water reducer. Under other unchanged conditions, it can further extend the initial setting time of concrete with a high mud content in fine aggregate in a high-temperature environment.

[0015] In some specific embodiments, the unsaturated phosphate monomer is at least one of acrylic acid phosphate and methacrylic acid phosphate.

[0016] In some specific embodiments, the unsaturated sulfonic acid or unsaturated sulfonate monomer is at least one of 2-acrylamido-2-methylpropanesulfonic acid and 2-acrylamido-2-methylpropanesulfonate sodium.

[0017] In some specific embodiments, the unsaturated hydroxy fatty acid ester monomer is at least one of hydroxyethyl acrylate, hydroxypropyl acrylate, hydroxyethyl methacrylate, and hydroxypropyl methacrylate.

[0018] In some specific embodiments, the chain transfer agent is at least one of mercaptoacetic acid, mercaptoethanol, and mercaptopropionic acid.

[0019] In a second aspect, a preparation method of the retarding polycarboxylate water reducer provided in this application adopts the following technical solution: A preparation method of a retarding polycarboxylate water reducer includes the following steps:

[0020] Add acrylic acid, the quaternary ammonium salt cationic monomer, and the unsaturated sulfonic acid or unsaturated sulfonate monomer to water with a weight of 20 - 25% of the total water formula, stir evenly to obtain solution A;

[0021] Add the unsaturated polyether monomer, the unsaturated phosphate monomer, and the unsaturated hydroxy fatty acid ester monomer to water with a weight of 20 - 25% of the total water formula, stir evenly to obtain solution B;

[0022] Add the oxidant to water with a weight of 10 - 15% of the total water formula to obtain solution C;

[0023] Add the reducing agent to water with a weight of 10 - 15% of the total water formula to obtain solution D;

[0024] Add the chain transfer agent to the remaining water to obtain solution E;

[0025] Drop part of solution C and solution D into solution A. The dropping amounts of solution C and solution D are 40 - 45% of their respective total weights, and the dropping speed ratio of solution C to solution D is (1.5 - 2.5):1. The dropping time is controlled within 100 - 120 min to obtain solution F;

[0026] While dropping B liquid, the remaining C liquid and the remaining D liquid into the F liquid simultaneously, control the dropping time within 120 - 150 min, then add the E liquid, and stir and react for 1 - 2 h to obtain a retarding polycarboxylate water reducer.

[0027] In this application, A liquid - E liquid are respectively prepared. First, part of the C liquid and D liquid are added to the A liquid, and after reacting to obtain the F liquid, then the B liquid, the remaining C liquid and the remaining D liquid are added to the F liquid, and continue to react. Finally, the E liquid is added for reaction to obtain a retarding polycarboxylate water reducer. Among them, using this method to prepare the retarding polycarboxylate water reducer is beneficial to further improving the retarding effect of the retarding polycarboxylate water reducer on the concrete mixture with the mud content of fine aggregate greater than 1.5% in a high - temperature environment.

[0028] To sum up, this application includes at least the following beneficial technical effects:

[0029] (1) The retarding polycarboxylate water reducer of this application is obtained by reacting an unsaturated polyether monomer with a specific structure with a quaternary ammonium salt cation monomer, an unsaturated sulfonic acid or unsaturated sulfonate monomer, an unsaturated phosphate monomer, an unsaturated hydroxy fatty acid ester monomer, acrylic acid, etc. through a specific ratio. Among them, this shrinkage - reducing polycarboxylate water reducer has low sensitivity to the mud in the aggregate, has anti - mud property, can be evenly dispersed in the concrete mixture with a high mud content of fine aggregate (more than 1.5%), and stably adsorbs on the surface of cement particles to form a water film. This water film has good thermal stability and can prevent the problem that water easily accelerates the penetration of water into cement in a high - temperature environment (>35°C), thereby delaying the hydration rate of cement in a high - temperature environment and effectively improving the retarding effect of the retarding polycarboxylate water reducer on the concrete mixture with the mud content of fine aggregate greater than 1.5% in a high - temperature environment.

[0030] (2) In this application, the unsaturated polyether monomer preferably is a composition of a first unsaturated polyether monomer and a second unsaturated polyether monomer with a specific ratio. Among them, R2 in the first unsaturated polyether monomer is a phenyl group, and R2 in the second unsaturated polyether monomer is a phenylalanine alkyl ester group, which is beneficial to further improving the anti - mud property of the retarding polycarboxylate water reducer and can further extend the initial setting time of the concrete with a high mud content of fine aggregate in a high - temperature environment.

[0031] (3) In this application, A liquid - E liquid are respectively prepared. First, part of the C liquid and D liquid are added to the A liquid, and after reacting to obtain the F liquid, then the B liquid, the remaining C liquid and the remaining D liquid are added to the F liquid, and continue to react. Finally, the E liquid is added for reaction to obtain a retarding polycarboxylate water reducer. Among them, using this method to prepare the retarding polycarboxylate water reducer is beneficial to further improving the retarding effect of the retarding polycarboxylate water reducer on the concrete mixture with the mud content of fine aggregate greater than 1.5% in a high - temperature environment. Detailed implementation mode

[0032] The present application will be further described below in conjunction with specific experiments.

[0033] Example

[0034]

Example 1

[0035] A retarding polycarboxylate water reducer is prepared from the following raw materials:

[0036] Unsaturated polyether monomer: 45 g; in this example, the unsaturated polyether monomer is the first unsaturated polyether monomer, and the structural formula of the first unsaturated polyether monomer is CH2=CHCH2O(CH2CH2O) 18 C6H5;

[0037] Quaternary ammonium salt cationic monomer: 20 g; in this example, the quaternary ammonium salt cationic monomer is specifically methacryloyloxyethyl dimethyl benzyl ammonium chloride;

[0038] Unsaturated sulfonic acid or unsaturated sulfonate monomer: 10 g; in this example, the unsaturated sulfonic acid or unsaturated sulfonate monomer is 2-acrylamido-2-methylpropanesulfonic acid;

[0039] Unsaturated phosphate monomer: 5.5 g; in this example, the unsaturated phosphate monomer is acrylic acid phosphate;

[0040] Unsaturated hydroxy fatty acid ester monomer: 6.2 g; in this example, the unsaturated hydroxy fatty acid ester monomer is hydroxyethyl acrylate; acrylic acid: 100 g;

[0041] Chain transfer agent: 1 g; in this example, the chain transfer agent is mercaptoacetic acid;

[0042] Oxidizing agent: 1.5 g; in this example, the oxidizing agent is ammonium persulfate;

[0043] Reducing agent: 0.75 g; in this example, the reducing agent is sodium sulfite;

[0044] Water: 500 g.

[0045] In this example, the preparation method of the retarding polycarboxylate water reducer includes the following steps:

[0046] Add unsaturated acrylic acid, quaternary ammonium salt cationic monomer, and unsaturated sulfonic acid or unsaturated sulfonate monomer to 25% of the total weight of water in the formula, and stir evenly to obtain solution A;

[0047] Add the unsaturated polyether monomer, unsaturated phosphate monomer, and unsaturated hydroxy fatty acid ester monomer to 25% of the total weight of water in the formula, and stir evenly to obtain solution B;

[0048] Add the oxidizing agent to 10% of the total weight of the water formulation to obtain Solution C;

[0049] Add the reducing agent to 10% of the total weight of the water formulation to obtain Solution D;

[0050] Add the chain transfer agent to the remaining water to obtain Solution E;

[0051] Dropwise add Solution B, Solution C, and Solution D into Solution A simultaneously, control the dropping time within 300 min, then add Solution E, and stir and react for 1.5 h to obtain the retarding polycarboxylate superplasticizer.

[0052]

Example 2

[0053] A retarding polycarboxylate superplasticizer, which is different from

Example 1

[0054] Unsaturated polyether monomer: 55 g; in this example, the unsaturated polyether monomer uses the second unsaturated polyether monomer, and the structural formula of the second unsaturated polyether monomer is CH2=CHCH2O(CH2CH2O) 18 C6H4CH2NHCOOCH3;

[0055] Quaternary ammonium salt cationic monomer: 15 g; in this example, the quaternary ammonium salt cationic monomer specifically uses methacryloyloxyethyl trimethyl ammonium chloride;

[0056] Unsaturated sulfonic acid or unsaturated sulfonate monomer: 15 g; in this example, the unsaturated sulfonic acid or unsaturated sulfonate monomer uses 2-acrylamido-2-methylpropanesulfonic acid sodium salt;

[0057] Unsaturated phosphate monomer: 7.5 g; in this example, the unsaturated phosphate monomer uses methacrylic acid phosphate;

[0058] Unsaturated hydroxy fatty acid ester monomer: 4.8 g; in this example, the unsaturated hydroxy fatty acid ester monomer uses 2-hydroxyethyl methacrylate;

[0059] Acrylic acid: 120 g;

[0060] Chain transfer agent: 2 g; in this example, the chain transfer agent uses mercaptopropionic acid;

[0061] Oxidizing agent: 2 g; in this example, the oxidizing agent uses sodium persulfate;

[0062] Reducing agent: 1 g; in this example, the reducing agent uses sodium bisulfite;

[0063] Water: 500 g.

[0064]

Example 3

[0065] A retarding polycarboxylate water reducer, which is different from [Example 1] in that the unsaturated polyether monomer is different. In this example, the unsaturated polyether monomer is the second unsaturated polyether monomer, and the structural formula of the second unsaturated polyether monomer is CH2=CHCH2O(CH2CH2O) 18 C6H4CH2NHCOOCH3.

[0066]

Example 4

[0067] A retarding polycarboxylate water reducer, which is different from [Example 1] in that the unsaturated polyether monomer is different. In this example, the unsaturated polyether monomer includes the first unsaturated polyether monomer and the second unsaturated polyether monomer. The structural formula of the first unsaturated polyether monomer is CH2=CHCH2O(CH2CH2O) 18 C6H5, and the structural formula of the second unsaturated polyether monomer is CH2=CHCH2O(CH2CH2O) 18 C6H4CH2NHCOOCH3, and the weight ratio of the first unsaturated polyether monomer to the second unsaturated polyether monomer is 1:1.

[0068]

Example 5

[0069] A retarding polycarboxylate water reducer, which is different from [Example 1] in that the unsaturated polyether monomer is different. In this example, the unsaturated polyether monomer includes the first unsaturated polyether monomer and the second unsaturated polyether monomer. The structural formula of the first unsaturated polyether monomer is CH2=CHCH2O(CH2CH2O) 18 C6H5, and the structural formula of the second unsaturated polyether monomer is CH2=CHCH2O(CH2CH2O) 18 C6H4CH2NHCOOCH3, and the weight ratio of the first unsaturated polyether monomer to the second unsaturated polyether monomer is 3:1.

[0070]

Example 6

[0071] A retarding polycarboxylate water reducer, which is different from [Example 1] in that the unsaturated polyether monomer is different. In this example, the unsaturated polyether monomer includes the first unsaturated polyether monomer and the second unsaturated polyether monomer. The structural formula of the first unsaturated polyether monomer is CH2=CHCH2O(CH2CH2O) 18 C6H5, and the structural formula of the second unsaturated polyether monomer is CH2=CHCH2O(CH2CH2O) 18 C6H4CH2NHCOOCH3, and the weight ratio of the first unsaturated polyether monomer to the second unsaturated polyether monomer is 1:3.

[0072]

Example 7

[0073] A retarding polycarboxylate water reducer, which is different from [Example 4] in that the value of n in the first unsaturated polyether monomer and the second unsaturated polyether monomer is different. In this example, the structural formula of the first unsaturated polyether monomer is CH2=CHCH2O(CH2CH2O) 25 C6H5, and the structural formula of the second unsaturated polyether monomer is CH2=CHCH2O(CH2CH2O) 25 C6H4CH2NHCOOCH3.

[0074]

Example 8

[0075] A retarding polycarboxylate water reducer, which is different from [Example 4] in that the quaternary ammonium salt cationic monomer is different. In this example, the quaternary ammonium salt cationic monomer adopts a composition of methacryloyloxyethyl trimethyl ammonium chloride and methacryloyloxyethyl dimethyl benzyl ammonium chloride, and the weight ratio of methacryloyloxyethyl trimethyl ammonium chloride to methacryloyloxyethyl dimethyl benzyl ammonium chloride is 1:4.

[0076]

Example 9

[0077] A retarding polycarboxylate water reducer, which is different from [Example 4] in that the quaternary ammonium salt cationic monomer is different. In this example, the quaternary ammonium salt cationic monomer adopts a composition of dimethyldiallyl ammonium chloride and methacryloyloxyethyl dimethyl benzyl ammonium chloride, and the weight ratio of dimethyldiallyl ammonium chloride to methacryloyloxyethyl dimethyl benzyl ammonium chloride is 1:4.

[0078]

Example 10

[0079] A retarding polycarboxylate water reducer, which is different from [Example 4] in that the quaternary ammonium salt cationic monomer is different. In this example, the quaternary ammonium salt cationic monomer adopts a composition of methacryloyloxyethyl trimethyl ammonium chloride and dimethyldiallyl ammonium chloride, and the weight ratio of methacryloyloxyethyl trimethyl ammonium chloride to dimethyldiallyl ammonium chloride is 1:4.

[0080]

Example 11

[0081] A retarding polycarboxylate water reducer, which is different from [Example 8] in that the preparation method of the retarding polycarboxylate water reducer is different.

[0082] In this example, the preparation method of the retarding polycarboxylate water reducer is as follows:

[0083] Add acrylic acid, quaternary ammonium salt cationic monomer, unsaturated sulfonic acid or unsaturated sulfonate monomer to 25% of the total weight of water in the water formula, stir evenly to obtain liquid A;

[0084] Add unsaturated polyether monomer, unsaturated phosphate monomer, and unsaturated hydroxy fatty acid ester monomer to 25% of the total weight of water in the water formulation, stir evenly to obtain Solution B;

[0085] Add the oxidizing agent to 10% of the total weight of water in the water formulation to obtain Solution C;

[0086] Add the reducing agent to 10% of the total weight of water in the water formulation to obtain Solution D;

[0087] Add the chain transfer agent to the remaining water to obtain Solution E;

[0088] Dropwise add part of Solution C and Solution D to Solution A. The dropping amounts of Solution C and Solution D are 40% of their respective total weights. The dropping speed ratio of Solution C to Solution D is 2:1, and the dropping time is controlled within 120 min to obtain Solution F;

[0089] Simultaneously dropwise add Solution B, the remaining Solution C, and the remaining Solution D to Solution F. The dropping time is controlled within 150 min, then add Solution E, and stir and react for 1.5 h to obtain the retarding polycarboxylate water reducer.

[0090] Comparative Example

[0091]

Comparative Example 1

[0092] A retarding polycarboxylate water reducer, which is different from

Example 1

[0093] In this comparative example, the retarding polycarboxylate water reducer is prepared from the following raw materials:

[0094] Unsaturated polyether monomer: 25 g; In this example, the unsaturated polyether monomer uses the first unsaturated polyether monomer, and the structural formula of the first unsaturated polyether monomer is CH2=CHCH2O(CH2CH2O) 18 C6H5;

[0095] Quaternary ammonium salt cationic monomer: 30 g; In this example, the quaternary ammonium salt cationic monomer specifically uses methacryloyloxyethyl dimethyl benzyl ammonium chloride;

[0096] Unsaturated sulfonic acid or unsaturated sulfonate monomer: 20 g; In this example, the unsaturated sulfonic acid or unsaturated sulfonate monomer uses 2-acrylamido-2-methylpropanesulfonic acid;

[0097] Unsaturated phosphate monomer: 2.5 g; In this example, the unsaturated phosphate monomer uses acrylic acid phosphate;

[0098] Unsaturated hydroxy fatty acid ester monomer: 9.2 g; In this example, the unsaturated hydroxy fatty acid ester monomer uses hydroxyethyl acrylate; Acrylic acid: 100 g;

[0099] Chain transfer agent: 1 g; in this example, the chain transfer agent is thioglycolic acid;

[0100] Oxidizing agent: 1.5 g; in this example, the oxidizing agent is ammonium persulfate;

[0101] Reducing agent: 0.75 g; in this example, the reducing agent is sodium sulfite;

[0102] Water: 500 g.

[0103] Performance detection test

[0104] The mix proportion of the reference concrete C30 is shown in Table 1 below. Among them, the cement used is Huaxin Cement PO42.5, the fineness modulus of the sand used is 2.6 - 2.9, and the mud content is 2.15%; the gravel used is of two grades, among which, 5 mm - 10 mm accounts for about 40%, and 10 mm - 20 mm accounts for about 60%.

[0105] Table 1

[0106]

[0107] Initial setting time difference test: Incorporate the retarding polycarboxylate superplasticizer in each example and comparative example into the above-mentioned reference concrete C30 at 0.5% (solid content) of the cement dosage to prepare concrete mixtures 1 - 12 respectively. Then, place the concrete mixtures in an environment with a temperature of 45°C and a humidity of 85%, and refer to the determination of the initial setting time in Section 11 of the setting time test in GB / T 50080 - 2016 to detect the initial setting time of each concrete mixture. Compare with the initial setting time of the reference concrete in Table 1, and record the difference between the initial setting times of the concrete mixtures 1 - 12 and the reference concrete. The larger the difference, the better the retarding effect of the retarding polycarboxylate superplasticizer.

[0108] Table 2

[0109]

[0110] The difference between Comparative Example 1 and Example 1 is that the mix ratio of each component of the retarding polycarboxylate superplasticizer in Comparative Example 1 is different from that in Example 1. From the data in Table 2, it can be seen that the retarding polycarboxylate superplasticizer in Example 1 has a much better retarding effect on the concrete mixture with a fine aggregate mud content greater than 1.5% in a high-temperature environment than in Comparative Document 1, indicating that the mix ratio between the raw material components affects the retarding effect of the retarding polycarboxylate superplasticizer.

[0111] Examples 3-6 are different from Example 1 in that the unsaturated polyether monomers are different. Among them, in Examples 4-6, the unsaturated polyether monomer uses a composition of a first unsaturated polyether monomer and a second unsaturated polyether monomer. In Example 4, the weight ratio of the first unsaturated polyether monomer to the second unsaturated polyether monomer is 1:1. In Example 5, the weight ratio of the first unsaturated polyether monomer to the second unsaturated polyether monomer is 3:1. In Example 6, the weight ratio of the first unsaturated polyether monomer to the second unsaturated polyether monomer is 1:3. Combining the data in Table 2, it can be seen that when the unsaturated polyether monomer uses a composition with the weight ratio of the first unsaturated polyether monomer to the second unsaturated polyether monomer in the range of 1:(1-1.5), it is beneficial to further improve the retarding effect of the retarding polycarboxylate superplasticizer on the concrete mixture with the fine aggregate mud content greater than 1.5% in a high-temperature environment.

[0112] The difference between Example 7 and Example 4 is that in Example 4, the value of n in the first unsaturated polyether monomer and the second unsaturated polyether monomer is within 15-20, and in Example 7, the value of n in the first unsaturated polyether monomer and the second unsaturated polyether monomer is greater than 20. Combining the data in Table 2, it can be seen that when the value of n in the unsaturated polyether monomer is within 15-20, it is beneficial to further improve the retarding effect of the retarding polycarboxylate superplasticizer on the concrete mixture with the fine aggregate mud content greater than 1.5% in a high-temperature environment.

[0113] Examples 8-10 are different from Example 4 in that the quaternary ammonium salt cationic monomers are different. Among them, in Example 8, the quaternary ammonium salt cationic monomer uses a composition with the weight ratio of methacryloyloxyethyl trimethyl ammonium chloride and methacryloyloxyethyl dimethyl benzyl ammonium chloride being 1:4. In Example 9, the quaternary ammonium salt cationic monomer uses a composition with the weight ratio of dimethyldiallyl ammonium chloride and methacryloyloxyethyl dimethyl benzyl ammonium chloride being 1:4. In Example 10, the quaternary ammonium salt cationic monomer uses a composition with the weight ratio of methacryloyloxyethyl trimethyl ammonium chloride and dimethyldiallyl ammonium chloride being 1:4. Combining the data in Table 1, it can be seen that when the quaternary ammonium salt cationic monomer uses a composition with the weight ratio of methacryloyloxyethyl trimethyl ammonium chloride and methacryloyloxyethyl dimethyl benzyl ammonium chloride in the range of 1:(3-4), it is beneficial to further improve the retarding effect of the retarding polycarboxylate superplasticizer on the concrete mixture with the fine aggregate mud content greater than 1.5% in a high-temperature environment.

[0114] The difference between Example 11 and Example 8 lies in that: the preparation method of the retarding polycarboxylate water reducer in Example 11 is different from that in Example 8. Among them, in Example 11, solutions A - E are respectively prepared first, then part of solution C and solution D are added to solution A, and after reacting to obtain solution F, then solution B, the remaining solution C and the remaining solution D are added to solution F, and the reaction continues. Finally, solution E is added for reaction to obtain the retarding polycarboxylate water reducer. From the data in Table 2, it can be seen that: using the method in Example 11 to prepare the retarding polycarboxylate water reducer is beneficial to further improving the retarding effect of the retarding polycarboxylate water reducer on the concrete mixture with a fine aggregate mud content greater than 1.5% in a high - temperature environment.

[0115] This specific implementation manner is only an interpretation of the present application, and it does not limit the present application. After reading this specification, those skilled in the art can make modifications that do not contribute creatively to this specific implementation manner as needed, but as long as they are within the scope of the claims of the present application, they are protected by the patent law.

Claims

1. A slow-setting polycarboxylate water-reducing agent, characterized in that: The invention comprises 45-55 parts by weight of an unsaturated polyether monomer, 15-20 parts by weight of a quaternary ammonium salt cationic monomer, 10-15 parts by weight of an unsaturated sulfonic acid or unsaturated sulfonate monomer, 5.5-7.5 parts by weight of an unsaturated phosphate monomer, 4.8-6.2 parts by weight of an unsaturated hydroxy fatty acid ester monomer, 100-120 parts by weight of acrylic acid, 1-2 parts by weight of a chain transfer agent, 1.5-2 parts by weight of an oxidant, 0.75-1 parts by weight of a reducing agent and 500 parts by weight of water, wherein the unsaturated polyether monomer has a general structural formula of R1CH2O(CH2CH2O): n R2, wherein the unsaturated polyether monomer includes a first unsaturated polyether monomer and a second unsaturated polyether monomer, in the first unsaturated polyether monomer, R1 is an alkenyl group and R2 is a phenyl group; in the second unsaturated polyether monomer, R1 is an alkenyl group and R2 is a phenylalanine alkyl ester group, and the weight ratio of the first unsaturated polyether monomer to the second unsaturated polyether monomer is 1: (1-1.5).

2. A slow-setting polycarboxylate water-reducing agent according to claim 1, characterized in that: In the unsaturated polyether monomer, the value of n is 15-20.

3. A slow-setting polycarboxylate water-reducing agent according to claim 1, characterized in that: The quaternary ammonium salt cationic monomer is at least one of dimethyldiallylammonium chloride, methacryloyloxyethyltrimethylammonium chloride, and methacryloyloxyethyldimethylbenzylammonium chloride.

4. A slow-setting polycarboxylate water-reducing agent according to claim 3, characterized in that: The quaternary ammonium salt cationic monomer is a composition of methacryloyloxyethyl trimethyl ammonium chloride and methacryloyloxyethyl dimethyl benzyl ammonium chloride, and the weight ratio of the methacryloyloxyethyl trimethyl ammonium chloride to the methacryloyloxyethyl dimethyl benzyl ammonium chloride is 1: (3-4).

5. A slow-setting polycarboxylate water-reducing agent according to claim 1, characterized in that: The unsaturated phosphate monomer is at least one of acrylic acid phosphate and methacrylic acid phosphate.

6. A slow-setting polycarboxylate water-reducing agent according to claim 1, characterized in that: The unsaturated sulfonic acid or unsaturated sulfonate monomer is at least one of 2-acrylamide-2-methylpropane sulfonic acid and sodium 2-acrylamide-2-methylpropane sulfonate.

7. A slow-setting polycarboxylate water-reducing agent according to claim 1, characterized in that: The unsaturated hydroxy fatty acid ester monomer is at least one of hydroxyethyl acrylate, hydroxypropyl acrylate, hydroxyethyl methacrylate and hydroxypropyl methacrylate.

8. The slow-setting polycarboxylate water-reducing agent according to claim 1, characterized in that: The chain transfer agent is at least one of thioglycolic acid, mercaptoethanol and mercaptopropionic acid.

9. A method for preparing a slow-setting polycarboxylate water-reducing agent according to any one of claims 1 to 8, characterized in that: The following steps are involved: Add acrylic acid, quaternary ammonium salt cationic monomer, unsaturated sulfonic acid or unsaturated sulfonate monomer to water with a total weight of 20-25% of the water formula, stir evenly, and obtain liquid A; Add unsaturated polyether monomer, unsaturated phosphate monomer and unsaturated hydroxy fatty acid ester monomer to water with a total weight of 20-25% of the water formula, stir evenly to obtain liquid B; Add the oxidant to water in an amount of 10-15% of the total weight of the water formula to obtain liquid C; Add the reducing agent to water in an amount of 10-15% of the total weight of the water formula to obtain liquid D; Add the chain transfer agent to the remaining amount of water to obtain liquid E; Add part of liquid C and liquid D dropwise to liquid A, the amount of liquid C and liquid D added is 40-45% of their respective total weights, the dropwise acceleration ratio of liquid C and liquid D is (1.5-2.5):1, and the dropwise addition time is controlled at 100-120 min to obtain liquid F; Add liquid B, the remaining liquid C and the remaining liquid D to liquid F at the same time, and control the dropping time to 120-150 minutes. Then add liquid E and stir the reaction for 1-2 hours to obtain a slow-setting polycarboxylate water-reducing agent.

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