Preparation method of ester-ether copolymerization type polycarboxylic acid water reducer

Abstract

The invention provides a preparation method of an ester-ether copolymerization type polycarboxylic acid water reducing agent, and relates to the technical field of water reducing agent preparation. Comprising the following steps: S1, stirring and mixing an ether monomer, an esterified monomer, water and an oxidizing agent according to a mass ratio of (90-240): (120-300): (120-240): (1-5) at 30-40 DEG C until the materials are dissolved to obtain a mixed solution; s2, uniformly mixing unsaturated acid, a chain transfer agent and water according to a mass ratio of (20-60): (1-4): (60-80) to prepare a solution A; uniformly mixing vitamin C, sodium hydrogen sulfite and water according to the mass ratio of (0.2-0.8): (0.2-1): (60-80) to prepare a solution B; and S3, simultaneously dropwise adding the solution A and the solution B into the mixed solution at a constant speed at the temperature of 30-40 DEG C and at the stirring speed of 80-300r / min, and then continuously keeping the temperature for 1 hour at the temperature when dropwise adding is finished, thereby obtaining the ester-ether copolymerization type polycarboxylic acid water reducing agent. The prepared ester-ether copolymerized polycarboxylic acid water reducing agent is good in water reducing effect, simple in preparation process and free of implosion.

Description

Technical Field

[0001] The present invention relates to the technical field of water reducer preparation, and particularly relates to a preparation method of an ester-ether copolymerized polycarboxylate water reducer. Background Art

[0002] Polycarboxylate water reducers include ester-type polycarboxylate water reducers and ether-type polycarboxylate water reducers. The ester-type polycarboxylate water reducer can be obtained by polymerizing an esterified macromonomer MAAMPEG, which is obtained by esterifying methoxypolyethylene glycol MPEG, methacrylic acid, a polymerization inhibitor and a catalyst at high temperature, with an oxidant at high temperature. However, this process is complex, requires high-temperature reaction, nitrogen protection is required during the esterification and polymerization processes, and generally only water reducer products with a concentration of 20-30% can be prepared, and the water reduction effect is poor.

[0003] The water reduction effect of ether-type polycarboxylate water reducers is better. Therefore, in order to improve the water reduction effect of polycarboxylate water reducers, researchers have proposed the synthesis idea of ester-ether copolymerized polycarboxylate water reducers. For example, the patent of Kezhijie New Materials Group Co., Ltd. (application number: CN201610820491.3, title: A low-sensitivity anti-sludge ether-ester copolymerized polycarboxylate water reducer and its preparation method) discloses a preparation method of an anti-sludge type ether-ester copolymerized polycarboxylate water reducer, but the preparation process of this patent is complex, and the water reduction effect of the prepared ester-ether copolymerized polycarboxylate water reducer is not ideal. In addition, Hunan Jinhua Da Building Materials Co., Ltd. has disclosed a viscosity-reducing type ester-ether copolymerized polycarboxylate water reducer and its room-temperature preparation method (application number: CN202111402924.0), the preparation raw materials are cumbersome, the preparation process requires continuous monitoring of the pH value change of the reaction system, and the control is strict, which is not conducive to large-scale production and application. Summary of the Invention

[0004] (1) Technical Problems to be Solved

[0005] In view of the deficiencies of the prior art, the present invention provides a preparation method of an ester-ether copolymerized polycarboxylate water reducer, which solves the technical problem that the water reduction effect of the ester-ether copolymerized polycarboxylate water reducer prepared by the existing process is poor.

[0006] (2) Technical Solutions

[0007] To achieve the above object, the present invention is realized through the following technical solutions:

[0008] A preparation method of an ester-ether copolymerized polycarboxylate water reducer includes the following steps:

[0009] S1. Mix an ether monomer, an esterification monomer, water, and an oxidant in a mass ratio of (90 - 240):(120 - 300):(120 - 240):(1 - 5) and stir and mix at 30°C - 40°C until dissolved to obtain a mixed solution;

[0010] S2. Mix unsaturated acid, chain transfer agent, and water in a mass ratio of (20 - 60):(1 - 4):(60 - 80) uniformly to prepare solution A.

[0011] Mix vitamin C, sodium bisulfite, and water in a mass ratio of (0.2 - 0.8):(0.2 - 1):(60 - 80) uniformly to prepare solution B.

[0012] S3. At a temperature of 30°C - 40°C and a stirring speed of 80 - 300 r / min, simultaneously and uniformly dropwise add solution A and solution B to the mixture. The dropping time of solution A is (1 - 3) h, and the dropping time of solution B is (1.5 - 3.5) h. Then, keep the temperature at the temperature at the end of the dropping for 1 h to obtain the ester - ether copolymer polycarboxylate superplasticizer.

[0013] In S1, the esterification monomer is a methoxypolyethylene glycol methacrylate monomer, where n MAA :n MPEG = 3:1 to 5:1, M MPEG = 1200.

[0014] In S1, the oxidant is a peroxide oxidant.

[0015] The peroxide oxidant includes an organic peroxide oxidant and an inorganic peroxide oxidant, and the mass ratio of the organic peroxide oxidant to the inorganic peroxide oxidant is 2:1.

[0016] The organic peroxide oxidant is selected from tert - butyl peroxybenzoate or tert - butyl peroxy - 2 - ethylhexanoate, and the inorganic peroxide oxidant is selected from hydrogen peroxide and ammonium persulfate.

[0017] The mass ratio of hydrogen peroxide to ammonium persulfate is 2:1.

[0018] The mass percentage concentration of hydrogen peroxide is selected from any one of 27.5%, 30%, and 35%.

[0019] In S1, the polyether monomer is selected from at least one of allyl polyoxyethylene ether, isopentenol polyoxyethylene ether, and diethylene glycol mono - vinyl polyoxyethylene ether.

[0020] In S2, the unsaturated acid is selected from at least one of methacrylic acid, acrylic acid, maleic anhydride, and itaconic acid.

[0021] In S3, a peristaltic pump is used to dropwise add solution A and solution B.

[0022] A preparation method of an ester - ether copolymer polycarboxylate superplasticizer, comprising the following steps:

[0023] S1. Mix isopentenyl alcohol polyoxyethylene ether TPEG, methoxypolyethylene glycol methacrylate monomer, water, tert-butyl perbenzoate, hydrogen peroxide and ammonium persulfate in a mass ratio of 180:180:240:2:0.7:0.3 under stirring at 30°C - 40°C until dissolved to obtain a mixed solution;

[0024] S2. Mix acrylic acid, mercaptoacetic acid and water in a mass ratio of 40:2.34:70 and mix evenly to prepare solution A; mix vitamin C, sodium bisulfite and water in a mass ratio of 0.51:0.5:70 and mix evenly to prepare solution B;

[0025] S3. At a stirring speed of 200 r / min at 35°C, simultaneously and uniformly dropwise add solution A and solution B to the mixed solution. The dropping time of solution A is 2 h, and the dropping time of solution B is 2.5 h. Then keep the temperature at the temperature at the end of dropping for 1 h to obtain the ester-ether copolymer polycarboxylate superplasticizer.

[0026] (III) Beneficial effects

[0027] The present invention provides a preparation method of an ester-ether copolymer polycarboxylate superplasticizer. Compared with the prior art, it has the following beneficial effects:

[0028] The preparation method of the ester-ether copolymer polycarboxylate superplasticizer provided by the present invention includes stirring and preparing a mixed solution by mixing an esterifying monomer, an ether monomer, water and a composite oxidant in a mass ratio of (120 - 300):(90 - 240):(120 - 240):(1 - 5) at 30°C - 40°C, and then simultaneously and uniformly dropwise adding solution A and solution B to the mixed solution at a stirring speed of 80 - 300 r / min at 30°C - 40°C. Among them, the composite oxidant includes hydrogen peroxide, ammonium persulfate and tert-butyl perbenzoate or tert-butyl peroxyvalerate. Through the feeding sequence of first mixing the esterifying monomer and the ether to prepare a mixed solution and then uniformly dropwise adding solution A and solution B to the mixed solution and the synergistic effect of the composite oxidant, the ester-ether copolymer polycarboxylate superplasticizer prepared by the present invention has good water-reducing effect, and the preparation process is simple and no explosion polymerization occurs. Specific embodiments

[0029] To make the purposes, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention are clearly and completely described. Obviously, the described embodiments are some, but not all, of the embodiments of the present invention. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the protection scope of the present invention.

[0030] The embodiment of the present application provides a preparation method of an ester-ether copolymer polycarboxylate water reducer, which solves the technical problem of poor water reduction effect of the ester-ether copolymer polycarboxylate water reducer prepared by the existing process.

[0031] The technical solution in the embodiment of the present application to solve the above technical problem is generally as follows:

[0032] The ester polycarboxylate water reducer can be obtained by polymerizing the esterified macromonomer MAAMPEG, which is obtained by esterifying methoxypolyethylene glycol MPEG, methacrylic acid, a polymerization inhibitor and a catalyst at high temperature, with an oxidant at high temperature. However, this process is complex and requires high-temperature reaction. Nitrogen protection needs to be introduced during the esterification and polymerization processes, and generally only a water reducer product with a concentration of 20-30% can be prepared. In order to improve the preparation process of the ester polycarboxylate water reducer, the inventor tried to prepare the ester polycarboxylate water reducer by polymerizing the esterified monomer at room temperature under the conditions of an oxidation-reduction system, and found that explosive polymerization occurred during the heat preservation process after the dropping was completed.

[0033] The present application provides a method for preparing an ester-ether copolymer water reducer under lower temperature conditions, which solves the problem of gelation during the room-temperature polymerization of the esterified monomer under the conditions of an oxidation-reduction system. The prepared water reducer has a solid content of 40-50%, a higher water reduction rate, stronger dispersion ability, significantly improves the air entrainment of concrete in a low-pressure environment, and is also beneficial to improving the workability of manufactured sand concrete.

[0034] In order to better understand the above technical solution, the above technical solution will be described in detail below in conjunction with specific embodiments.

[0035] Example 1

[0036] This embodiment provides a preparation method of an ester-ether copolymer polycarboxylate water reducer, including the following steps:

[0037] S1. Mix C5 polyether TPEG, esterified monomer MAAMPEG (where n MAA :n MPEG = 5:1, M MPEG = 1200), water, and a composite oxidant in a mass ratio of 180:180:240:3, and stir and mix them at a stirring speed of 80 r / min and a temperature of 40 °C until dissolved to obtain a mixed solution. The composite oxidant is a mixture of tert-butyl peroxybenzoate, 27.5% hydrogen peroxide, and ammonium persulfate; the mass ratio of tert-butyl peroxybenzoate, hydrogen peroxide, and ammonium persulfate is 2:0.6:0.4.

[0038] S2. Mix acrylic acid (AA), mercaptoacetic acid (QY), and water in a mass ratio of 20:2.34:70 and uniformly prepare solution A;

[0039] Mix vitamin C (VC), sodium bisulfite, and water evenly according to a mass ratio of 0.51:0.5:70 to prepare solution B;

[0040] S3. At a stirring speed of 40 °C and 100 r / min, simultaneously and uniformly drip solution A and solution B into the mixed solution using a peristaltic pump. The dripping time of solution A is 2 h, and the dripping time of solution B is 2.5 h. Then, keep the temperature at the temperature at the end of the dripping for 1 h to obtain the ester-ether copolymer polycarboxylate superplasticizer. The theoretical solid content of the prepared ester-ether copolymer polycarboxylate superplasticizer is 40.76%.

[0041] Example 2

[0042] The difference between this example and Example 1 lies in the different mass fractions of each raw material, as shown in Table 1 for details.

[0043] The composite oxidant in this example is different from that in Example 1. Specifically, it is a mixture of tert-butyl peroxy pivalate, 30% hydrogen peroxide, and ammonium persulfate; the mass ratio of tert-butyl peroxy pivalate, 30% hydrogen peroxide, and ammonium persulfate is 2:0.6:0.4.

[0044] Other conditions are the same as in Example 1.

[0045] The theoretical solid content of the prepared ester-ether copolymer polycarboxylate superplasticizer is 43.89%.

[0046] Example 3

[0047] The difference between this example and Example 1 lies in the different mass fractions of each raw material, as shown in Table 1 for details.

[0048] The composite oxidant in this example is different from that in Example 1. Specifically, it is a mixture of tert-butyl peroxybenzoate, 35% hydrogen peroxide, and ammonium persulfate; the mass ratio of tert-butyl peroxybenzoate, hydrogen peroxide, and ammonium persulfate is 2:0.6:0.4.

[0049] Other conditions are the same as in Example 1.

[0050] The theoretical solid content of the prepared ester-ether copolymer polycarboxylate superplasticizer is 37.63%.

[0051] Example 4

[0052] The difference between this example and Example 1 lies in the different mass fractions of each raw material, as shown in Table 1 for details.

[0053] The composite oxidant in this example is different from that in Example 1. Specifically, it is a mixture of tert-butyl peroxy pivalate, 35% hydrogen peroxide, and ammonium persulfate; the mass ratio of tert-butyl peroxy pivalate, hydrogen peroxide, and ammonium persulfate is 2:0.6:0.4.

[0054] Others are the same as in Example 1.

[0055] The theoretical solid content of the prepared ester-ether copolymer polycarboxylate water reducer is 36.06%.

[0056] Example 5

[0057] The difference between this example and Example 1 lies in that the mass parts of each raw material are different, as specifically shown in Table 1.

[0058] Others are the same as in Example 1.

[0059] The theoretical solid content of the prepared ester-ether copolymer polycarboxylate water reducer is 50%.

[0060] Example 6

[0061] The difference between this example and Example 1 lies in that the mass parts of each raw material are different, as specifically shown in Table 1.

[0062] The composite oxidant in this example is different from that in Example 1. Specifically, it is a mixture of tert-butyl peroxybenzoate, 30% hydrogen peroxide, and ammonium persulfate; the mass ratio of tert-butyl peroxybenzoate, hydrogen peroxide, and ammonium persulfate is 2:0.6:0.4.

[0063] Others are the same as in Example 1.

[0064] The theoretical solid content of the prepared ester-ether copolymer polycarboxylate water reducer is 50%.

[0065] Example 7

[0066] The difference between this example and Example 1 lies in that the mass parts of each raw material are different, as specifically shown in Table 1.

[0067] The composite oxidant in this example is different from that in Example 1. Specifically, it is a mixture of tert-butyl peroxybenzoate, 30% hydrogen peroxide, and ammonium persulfate; the mass ratio of tert-butyl peroxybenzoate, hydrogen peroxide, and ammonium persulfate is 2:0.6:0.4.

[0068] Others are the same as in Example 1. Polymerization explosion occurred during the heat preservation process after the dropping was completed.

[0069] The theoretical solid content of the ester-ether copolymer polycarboxylate water reducer is 50%.

[0070] Example 8

[0071] The difference between this example and Example 1 lies in that the mass parts of each raw material are different, as specifically shown in Table 1.

[0072] The composite oxidant in this example is different from that in Example 1. Specifically, it is a mixture of tert-butyl peroxy pivalate, 27.5% hydrogen peroxide, and ammonium persulfate; the mass ratio of tert-butyl peroxy pivalate, hydrogen peroxide, and ammonium persulfate is 2:0.6:0.4.

[0073] The others are the same as in Example 1.

[0074] The theoretical solid content of the prepared ester-ether copolymer polycarboxylate superplasticizer is 41.55%.

[0075] Example 9

[0076] The difference between this example and Example 1 is that the mass parts of each raw material are different, as shown in Table 1 specifically.

[0077] The composite oxidant in this example is different from that in Example 1, specifically a mixture of tert-butyl peroxy pivalate, 30% hydrogen peroxide and ammonium persulfate; the mass ratio of tert-butyl peroxy pivalate, hydrogen peroxide and ammonium persulfate is 2:0.6:0.4.

[0078] The others are the same as in Example 1.

[0079] The theoretical solid content of the prepared ester-ether copolymer polycarboxylate superplasticizer is 42.30%.

[0080] Example 10

[0081] The difference between this example and Example 1 is that the mass parts of each raw material are different, as shown in Table 1 specifically.

[0082] The composite oxidant in this example is different from that in Example 1, specifically a mixture of tert-butyl peroxybenzoate, 35% hydrogen peroxide and ammonium persulfate; the mass ratio of tert-butyl peroxybenzoate, hydrogen peroxide and ammonium persulfate is 2:0.6:0.4.

[0083] The others are the same as in Example 1.

[0084] The theoretical solid content of the prepared ester-ether copolymer polycarboxylate superplasticizer is 43.03%.

[0085] Table 1 Dosages of each component in Examples 1 - 10

[0086]

[0087] Comparative Example 1

[0088] The difference between this comparative example and Example 1 is that the esterification monomer is not included in the mixed solution, and the esterification monomer is made into an esterification monomer solution with a mass concentration of 60%, and the 60% esterification monomer solution is added dropwise to the mixed solution while adding solution A and solution B dropwise. Specifically, it includes the following steps:

[0089] S1. Mix the ether monomer C5 polyether TPEG, water, and composite oxidant in a mass ratio of 180:240:3 under stirring at a speed of 80 r / min and a temperature of 40 °C until dissolved to obtain a mixed solution. The composite oxidant is a mixture of tert-butyl perbenzoate, 27.5% hydrogen peroxide, and ammonium persulfate; the mass ratio of tert-butyl perbenzoate, hydrogen peroxide, and ammonium persulfate is 2:0.6:0.4.

[0090] S2. Mix acrylic acid (AA), mercaptoacetic acid (QY), and water in a mass ratio of 20:2.34:70 uniformly to prepare solution A;

[0091] Mix vitamin C (VC), sodium bisulfite, and water in a mass ratio of 0.51:0.5:70 uniformly to prepare solution B;

[0092] S3. At a temperature of 40 °C and a stirring speed of 100 r / min, simultaneously and uniformly drip solution A, solution B, and 60% ester monomer solution (MAAMPEG, where n MAA :n MPEG = 5:1, M MPEG = 1200) into the mixed solution. The dropping time of solution A is 2 h, the dropping time of solution B is 2.5 h, and the dropping amount of the 60% ester monomer solution is in a mass ratio of 180:180 to the ether monomer C5 polyether TPEG. Then, keep warm for 1 h at the temperature at the end of the dropping to obtain the ester-ether copolymer polycarboxylate superplasticizer.

[0093] Comparative Example 2

[0094] The difference between this comparative example and Example 1 is that tert-butyl perbenzoate is used to replace the composite oxidant in Example 1.

[0095] Others are the same as in Example 1.

[0096] Comparative Example 3

[0097] The difference between this comparative example and Example 1 is that a mixture of 27.5% hydrogen peroxide and ammonium persulfate is used to replace the composite oxidant in Example 1.

[0098] Others are the same as in Example 1.

[0099] Comparative Example 4

[0100] This comparative example provides a preparation method of an ester-ether copolymer polycarboxylate superplasticizer, including the following steps:

[0101] S1. Mix the ether monomer EPEG, water, 27.5% hydrogen peroxide, and 1.5% ferrous sulfate in a mass ratio of 60:175:2.73:3.3 under stirring at a speed of 80 r / min and a temperature of 40 °C until dissolved to obtain a mixed solution.

[0102] S2. Mix acrylic acid (AA), QB, water, and 30% NaOH solution with a mass ratio of 25:1.4:20:9.5 evenly to prepare solution A.

[0103] Mix vitamin C (VC) and water with a mass ratio of 0.55:30 evenly to prepare solution B.

[0104] S3. At a stirring speed of 100 r / min and a temperature of 40 °C, simultaneously and uniformly drip solution A, solution B, and 60% esterified monomer solution (MAAMPEG, where n MAA :n MPEG = 5:1, M MPEG = 1200) into the mixed solution. The dripping time of solution A is 40 min, the dripping time of solution B is 2.5 h, and the mass ratio of the dripping amount of 60% esterified monomer solution to the ether monomer EPEG is 150:160. Then, keep the temperature at the end of dripping for 1 h to obtain the ester-ether copolymer polycarboxylate superplasticizer.

[0105] Comparative Example 5

[0106] This comparative example provides a preparation method of an ester-ether copolymer polycarboxylate superplasticizer, including the following steps:

[0107] S1. Mix the ether monomer VPEG, water, 27.5% hydrogen peroxide, and 1.5% ferrous sulfate with a mass ratio of 160:175:2.73:3.3 at a stirring speed of 80 r / min and a temperature of 40 °C until dissolved to obtain a mixed solution.

[0108] S2. Mix acrylic acid (AA), QB, water, and 30% NaOH solution with a mass ratio of 25:1.4:20:9.5 evenly to prepare solution A.

[0109] Mix vitamin C (VC) and water with a mass ratio of 0.55:30 evenly to prepare solution B.

[0110] S3. At a stirring speed of 100 r / min and a temperature of 40 °C, simultaneously and uniformly drip solution A, solution B, and 60% esterified monomer solution (MAAMPEG, where n MAA :n MPEG = 5:1, M MPEG = 1200) into the mixed solution. The dripping time of solution A is 2 h, the dripping time of solution B is 2.5 h, and the mass ratio of the dripping amount of 60% esterified monomer solution to the ether monomer VPEG is 150:160. Then, keep the temperature at the end of dripping for 1 h to obtain the ester-ether copolymer polycarboxylate superplasticizer.

[0111] Comparative Example 6

[0112] This comparative example provides a preparation method for an ester polycarboxylate water reducer, including the following steps:

[0113] S1. Mix 60% esterification monomer solution (MAAMPEG, where n MAA :n MPEG = 5:1, M MPEG = 1200), water, sodium hypophosphite, AA, and 27.5% H2O2 at a stirring speed of 80 r / min and a temperature of 40 °C until dissolved to obtain a mixed solution.

[0114] S2. Mix acrylic acid (AA) and water evenly to prepare solution A;

[0115] Mix vitamin C (VC) and water evenly to prepare solution B;

[0116] S3. At a stirring speed of 100 r / min and a temperature of 40 °C, simultaneously and uniformly drip solution A and solution B into the mixed solution. The dripping time of solution A is 2 h, and the dripping time of solution B is 2.5 h. Then, keep the temperature at the temperature at the end of the dripping and continue to heat preservation. Polymerization explosion occurred during the heat preservation process, and the ester polycarboxylate water reducer could not be prepared. The mass ratio of each component is shown in Table 2, and the theoretical solid content of the target water reducer is 33.4%.

[0117] Comparative Example 7

[0118] This comparative example is an improvement of Comparative Example 6. The difference from Comparative Example 6 is that the mass fractions of each component are different, and solution A includes a chain transfer agent QB, as shown in Table 2 specifically. There is no temperature change during the reaction process, and no polymerization explosion occurred during the heat preservation process after the dripping ended. An ester polycarboxylate water reducer was prepared. Others are the same as Comparative Example 6. The theoretical solid content of the target water reducer is 30.2%.

[0119] Comparative Example 8

[0120] This comparative example is a further improvement of Comparative Example 6. The difference from Comparative Example 6 is that the mass fractions of each component are different, solution A includes a chain transfer agent QB, and the specific dosages of each component are shown in Table 2. There is no temperature change during the reaction process, and no polymerization explosion occurred during the heat preservation process after the dripping ended. An ester polycarboxylate water reducer was prepared. Others are the same as Comparative Example 6. The theoretical solid content of the target water reducer is 30.4%.

[0121] Comparative Example 9

[0122] This comparative example is a further improvement of Comparative Example 6. The difference from Comparative Example 6 is that the mass fractions of each component are different, sodium hypophosphite is not included, solution A includes a chain transfer agent QY-OH, and the specific dosages of each component are shown in Table 2. There is no temperature change during the reaction process, and no polymerization explosion occurred during the heat preservation process after the dripping ended. An ester polycarboxylate water reducer was prepared. Others are the same as Comparative Example 6. The theoretical solid content of the target water reducer is 29.9%.

[0123] Table 2 Dosages of each component in Comparative Examples 6-9

[0124]

[0125] Comparative Example 10

[0126] This comparative example provides a method for synthesizing an ester polycarboxylate water reducer at high temperature, including the following steps:

[0127] Mix the esterification monomer and water evenly at 95 °C to prepare solution A; mix ammonium persulfate and water evenly to prepare solution B; add water to the reaction kettle, and dropwise add solution A and solution B to the water respectively at a stirring speed of 80 r / min and a temperature of 95 °C. The dropping time of solution A is 4 h, and the dropping time of solution B is 4.5 h to prepare an ester polycarboxylate water reducer. The mass ratio of each component is shown in Table 3. The theoretical solid content of the target water reducer is 12.2%.

[0128] Comparative Example 11

[0129] The difference between this comparative example and Comparative Example 10 is that the mass parts of each component are different, as shown in Table 3 specifically. The theoretical solid content of the target water reducer is 21.32%.

[0130] Table 3 Dosages of each component in Comparative Examples 10 and 11

[0131]

[0132] The fluidity of the neat cement pastes of the water reducers prepared in Examples 1-10 and Comparative Examples 1-11 was tested to characterize their water-reducing effects. The lower the solid content by weight, the larger the fluidity, indicating a better water-reducing effect and also a better dispersibility of the water reducer.

[0133] Test method for fluidity of neat cement paste: Using the instruments and methods specified in GB 8077-2012 "Test Methods for Homogeneity of Concrete Admixtures", select P·O42.5 Conch Cement and test with a water-binder ratio of 0.29. The results are shown in Table 4.

[0134] Table 4 Fluidity of the neat cement pastes of the water reducers prepared in Examples 1-10 and Comparative Examples 1-11

[0135]

[0136]

[0137] Note: The solid content by weight characterizes the dosage of the water reducer, K0: fluidity at 0 minute, K 20min : fluidity at 20 minutes, K 40min : fluidity at 40 minutes.

[0138] As can be seen from Examples 1-10 in Table 4, when the mass ratio of ester to ether is (120 - 300):(90 - 240) and the acid (AA) to ether ratio is (20 - 50):(90 - 240), the water-reducing effect of the prepared ester-ether copolymer water reducer is better. However, as can be seen from Example 7, when the mass ratio of ester to ether is 450:90, the dosage of the esterification monomer is too high, and there is still the situation of explosive polymerization and gelation in the system.

[0139] As can be seen from the data of Comparative Example 1 in Table 4, when the feeding sequence of adding the esterification monomer solution dropwise to the mixed solution is adopted, the water-reducing effect of the prepared water reducer is poor. As can be seen from the data of Comparative Example 2, when the oxidant only includes tert-butyl peroxybenzoate, the water-reducing effect of the prepared water reducer is poor. As can be seen from the data of Comparative Example 3, when the oxidant only includes hydrogen peroxide and ammonium persulfate, the water-reducing effect of the prepared water reducer is poor. Therefore, mixing the esterification monomer and ether first to prepare a mixed solution and then dropping Solution A and Solution B into the mixed solution, and using a composite oxidant at the same time are the keys to obtaining a better water-reducing effect of the water reducer prepared by the preparation method of this application.

[0140] As can be seen from the data of Comparative Examples 10 and 11 in Table 4, when the polycarboxylate water reducer synthesized from ester polyether is synthesized at a relatively low concentration under high-temperature conditions, the water-reducing performance of the prepared water reducer is good. In Comparative Example 6, after increasing the concentration of the reactants and changing to room-temperature polymerization, the system did not react sufficiently during the dropping process, and the phenomenon of explosive polymerization and gelation occurred during the heat preservation process after the dropping was completed. On this basis, in Comparative Examples 7, 8, and 9, other chain transfer agents (QB, QY-OH) were used, and the dispersion performance and water-reducing effect of the prepared water reducer were still not good. The dosage of the prepared water reducer is more than twice that of the water reducer synthesized under high-temperature and low-concentration conditions in Comparative Example 10.

[0141] It should be noted that in this article, relational terms such as first and second are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any actual relationship or order between these entities or operations. Moreover, the term "comprising", "including" or any other variant thereof is intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements not only includes those elements, but also includes other elements not expressly listed, or also includes elements inherent to such process, method, article or device. Without further limitation, an element defined by the statement "including a..." does not exclude the existence of additional identical elements in the process, method, article or device including the said element.

[0142] The above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it; although the present invention has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that: they can still modify the technical solutions recorded in the foregoing embodiments, or perform equivalent replacements on some of the technical features; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the spirit and scope of the technical solutions of the various embodiments of the present invention. Where the present invention is not described in detail, it is the well-known technology of those skilled in the art.

Claims

1. A preparation method of an ester-ether copolymerization type polycarboxylate water reducer, characterized in that, It includes the following steps: S1. Ether monomers, esterification monomers, water, and an oxidant are stirred and mixed at 30°C - 40°C in a mass ratio of (90 - 240):(120 - 300):(120 - 240):(1 - 5) until dissolved to obtain a mixed solution; S2. Unsaturated acids, a chain transfer agent, and water are mixed evenly in a mass ratio of (20 - 60):(1 - 4):(60 - 80) to prepare solution A; Vitamin C, sodium bisulfite, and water are mixed evenly in a mass ratio of (0.2 - 0.8):(0.2 - 1):(60 - 80) to prepare solution B; S3. At 30°C - 40°C and a stirring speed of 80 - 300 r / min, solution A and solution B are simultaneously and uniformly dropped into the mixed solution at a constant speed. The dropping time of solution A is (1 - 3) h, and the dropping time of solution B is (1.5 - 3.5) h. Then, it is kept warm for 1 h at the temperature at the end of the dropping to obtain the ester - ether copolymer polycarboxylate water - reducing agent.

2. The preparation method according to claim 1, characterized in that, In S1, the esterified monomer is a methoxypolyethylene glycol methacrylate esterified monomer, where n MAA :n MPEG = 3:1 - 5:1, M MPEG = 1200.

3. The preparation method according to claim 1, characterized in that, In S1, the oxidant is a peroxide oxidant.

4. The preparation method according to claim 3, characterized in that, The peroxide oxidant includes an organic peroxide oxidant and an inorganic peroxide oxidant, and the mass ratio of the organic peroxide oxidant to the inorganic peroxide oxidant is 2:

1.

5. The preparation method according to claim 4, characterized in that, The organic peroxide oxidant is selected from tert - butyl peroxybenzoate or tert - butyl peroxy - 2 - ethylhexanoate, and the inorganic peroxide oxidant is selected from hydrogen peroxide and ammonium persulfate.

6. The preparation method according to claim 5, characterized in that, The mass ratio of hydrogen peroxide to ammonium persulfate is 3:

2.

7. The preparation method according to claim 5, characterized in that, The mass percentage concentration of hydrogen peroxide is selected from any one of 27.5%, 30%, and 35%.

8. The preparation method according to claim 1, characterized in that, In S1, the polyether monomer is selected from at least one of allyl polyoxyethylene ether, isopentenyl alcohol polyoxyethylene ether, and diethylene glycol mono - vinyl polyoxyethylene ether; In S2, the unsaturated acid is selected from at least one of methacrylic acid, acrylic acid, maleic anhydride, and itaconic acid.

9. The preparation method according to claim 1, wherein In S3, a peristaltic pump is used to drop solution A and solution B.

10. The preparation method according to claim 1, characterized in that, It includes the following steps: S1. Isopentenyl alcohol polyoxyethylene ether TPEG, methoxypolyethylene glycol methacrylate esterification monomer, water, tert - butyl peroxybenzoate, hydrogen peroxide, and ammonium persulfate are stirred and mixed at 30°C - 40°C in a mass ratio of 180:180:240:2:0.7:0.3 until dissolved to obtain a mixed solution; S2. Acrylic acid, mercaptoacetic acid, and water are mixed evenly in a mass ratio of 40:2.34:70 to prepare solution A; Vitamin C, sodium bisulfite, and water are mixed evenly in a mass ratio of 0.51:0.5:70 to prepare solution B; S3. At 35°C and a stirring speed of 200 r / min, solution A and solution B are simultaneously and uniformly dropped into the mixed solution at a constant speed. The dropping time of solution A is 2 h, and the dropping time of solution B is 2.5 h. Then, it is kept warm for 1 h at the temperature at the end of the dropping to obtain the ester - ether copolymer polycarboxylate water - reducing agent.

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