A long-lasting, stable, collapse-resistant phosphate-based water reducer and its preparation method

Abstract

The present invention discloses a long-lasting, stable, and slump-retaining phosphate-based water reducer and its preparation method, belonging to the technical field of concrete admixtures. The method comprises the following steps: performing a ring-opening reaction between monomer A and a polyamine monomer B to obtain an amino-containing monomer C; and performing a one-pot reaction between the amino-containing monomer C, a polyether macromonomer D, a small monomer E, a catalyst F, phosphorous acid, an aldehyde monomer G, and an aldehyde monomer J to obtain the long-lasting, stable, and slump-retaining phosphate-based water reducer. The preparation process of the present invention is simple, easy to industrialize, and has low production costs. No chloride ions are introduced, and the agent exhibits a 3-hour long-lasting, stable, and slump-retaining effect.

Description

Technical Field

[0001] The invention belongs to the technical field of concrete admixtures, and particularly relates to a long-acting, stable, collapse-resistant phosphate-based water reducer and a preparation method thereof. Background Art

[0002] Water reducers are a crucial component of high-performance concrete. While their usage is limited, they are indispensable. Concrete water reducers are the simplest, most effective, and most economical means of reducing cement usage, increasing the utilization of industrial waste, and improving concrete strength, performance, and durability. They are essential materials for modern concrete production.

[0003] Currently, polycarboxylate superplasticizers are the mainstream research topic in the industry, boasting high usage and excellent performance. They offer advantages such as low dosage, high water reduction rate, and good cement compatibility. However, with the rapid development of infrastructure, various large-scale, high-end projects are placing increasingly stringent demands on concrete performance. For example, nuclear power, hydropower, and some high-end concrete projects require a slump of 80-180mm for pumping. This poses significant challenges to concrete admixture technology, requiring long-term and stable slump reduction. However, numerous current projects have demonstrated that polycarboxylate admixtures still exhibit certain uncontrollable characteristics in achieving long-term, stable slump reduction, prone to overdosing, bleeding, reverse growth, and the inability to maintain slump over time.

[0004] A growing number of researchers are finding that, in response to these shortcomings of polycarboxylic acid admixtures, highly absorbent phosphate-based admixtures offer promising applications in long-term, stable slump reduction, such as slump reduction at low to medium slumps. Currently, numerous patents and publications disclose the preparation methods and results of phosphate-based water reducers.

[0005] Patent document CN105504297A reports a phosphite concrete superplasticizer with a polyethyleneimine structure. This polyether derivative can be used alone or in combination with sulfonate-based water reducers, polycarboxylate superplasticizers, and other agents. It effectively improves the flow and slump retention properties of concrete, particularly in controlling slump loss. However, the preparation process introduces a large amount of chloride ions, which may negatively impact the durability of reinforced concrete (such as accelerating steel corrosion), thus limiting its widespread application.

[0006] Ran Qian et al. (Synthesis, characterization and dispersion properties of aseries of bis(phosphonic acid)amino-terminated polymers[J]. Colloid.Polym.Sci., 2016, 294, 189-194) synthesized a series of low-molecular-weight polyether derivatives containing phosphite groups by phosphitylation of amino polyethers. These polyether derivatives exhibited good slump retention and water-reducing properties, and were less sensitive to clay. However, the high cost, low water-reducing properties, and high dosage of amino polyethers limited their large-scale application.

[0007] Patents CN107337788A and CN108033978A utilize the phosphitylation of polyols or polyether polyols to synthesize polyphosphate-based polymer admixtures, which initially achieve stable slump retention for low- to medium-slump concrete. While these methods work well in the laboratory, they have been less effective in actual engineering applications and have fallen short of the expected performance. Consequently, they have not been widely adopted, leaving room for improvement.

[0008] The above-mentioned patent articles and other articles disclose different types of phosphate-based water reducers, which show obvious collapse-preserving and water-reducing properties. However, due to various reasons, they are difficult to be applied on a large scale. Summary of the Invention

[0009] Technical problem to be solved: In response to the above technical problems, the present invention provides a long-acting, stable and collapse-resistant phosphate-based water reducer and a preparation method thereof. The preparation process is simple and easy to industrialize, and the production cost is low. No chloride ions are introduced, and it has a long-acting, stable and collapse-resistant effect of 3h.

[0010] Technical solution: A method for preparing a long-lasting, stable, and slump-resistant phosphate-based water reducer, comprising the following steps:

[0011] S1. performing a ring-opening reaction between monomer A and polyamine monomer B to obtain an amino group-containing monomer C;

[0012] S2. The amino-containing monomer C, polyether macromonomer D, small monomer E, catalyst F, phosphorous acid, aldehyde monomer G and aldehyde monomer J were reacted in one pot to obtain the long-lasting stable slump-proof phosphate-based water reducer;

[0013] Wherein, the structure of the monomer A is as follows:

[0014] ,

[0015] Where R1 is H, C1~C10 alkyl, NR 1 , OR 2 or O(CH2)s OR 3 , R 1 、R 2 、R 3 is a C1-C5 alkyl group, s is an integer of 1-8, R1 is at any position of the ortho-ortho pair, and the number is 1-3; X is NR 4 , O or O(CH2) f O, R 4 is a C1~C5 alkyl group, f is an integer of 1~8; Y is a C1~C5 alkyl group;

[0016] The structure of the polyether macromonomer D is shown below:

[0017] ,

[0018] Where Z is NR 5 , O or O(CH2) g O, R 5 is a C1-C5 alkyl group, g is an integer of 1-8; Q is a C2-C6 alkylene group, n=10-70; R2 is H or a C1-C10 alkyl group, R2 is in any position of an ortho-ortho pair, and the number is 1-3;

[0019] The structure of the small monomer E is shown below:

[0020] ,

[0021] Wherein R3 is H or C1~C10 alkyl, R3 is in any position of the ortho-ortho pair, and the number is 1~3; K is NR 6 , O or O[(CH2) p O] r , R 6 is a C1~C5 alkyl group, p is an integer of 1~8, r is an integer of 1~8; L is H or a C1~C5 alkyl group.

[0022] Preferably, the polyamine monomer B is ethylenediamine, propylenediamine, butylenediamine, pentanediamine, hexamethylenediamine, cyclohexanediamine, p-phenylenediamine, diethylenetriamine, triethylenetetramine, tetraethylenepentamine, pentaethylenehexamine or polyethylenepolyamine.

[0023] Preferably, the aldehyde monomer G is formaldehyde, trioxymethylene or paraformaldehyde.

[0024] Preferably, the aldehyde monomer J is acetaldehyde, propionaldehyde, isobutyraldehyde, butyraldehyde, valeraldehyde, heptanal, methylglyoxal, crotonaldehyde, 3-methylbutyraldehyde, hexanal, ethanolaldehyde, benzaldehyde, phenylacetaldehyde, octanal, decanal, cyclohexylcarboxaldehyde, 3-hydroxypropionaldehyde, 3-hydroxybutyraldehyde or 2-methylbutyraldehyde.

[0025] Preferably, Y is a C1~C3 alkyl group.

[0026] Preferably, R1 is H or C1~C5 alkyl or OR 2 , R 2 It is a C1~C5 alkyl group.

[0027] Preferably, X is O and Y is methylene.

[0028] Preferably, the molar ratio of the monomer A to the polyamine monomer B is (1-1.5):1.

[0029] Preferably, in S1, the reaction temperature is 80-120° C., and the reaction time is 1-5 h.

[0030] Preferably, R2 is H and Z is O.

[0031] Preferably, the QO is a mixture of ethylene oxide and propylene oxide, or ethylene oxide, wherein the molar percentage of ethylene oxide in the mixture is not less than 70%.

[0032] Preferably, R3 is H, K is O or O[(CH2) p O] r , p is 2, r is 1 or 2, and L is H.

[0033] Preferably, the catalyst F is concentrated sulfuric acid, methanesulfonic acid, trifluoromethanesulfonic acid, trifluoroethanesulfonic acid, benzenesulfonic acid or p-toluenesulfonic acid.

[0034] Preferably, in S2, the amount of catalyst F is 10-20% of the total mass of the reactants in S2.

[0035] Preferably, the aldehyde monomer G is 37 wt % of formaldehyde.

[0036] Preferably, the molar weight of the monomer A is q, the molar weight of the polyether macromonomer D is j, the molar weight of the small monomer E is t, and the molar weight of the unreacted amino hydrogen of the polyamine monomer B in S1 is k, then q:j=(0.5~3):1, t=(0.2~1.0)j, the molar weight of phosphorous acid is (1~1.2)k, the molar weight of the aldehyde monomer G is (1~1.2)*(q+j+t+k), and the molar weight of the aldehyde monomer J is (0.01~0.05)*(q+j+t).

[0037] Preferably, in S2, the reaction temperature is 100-140° C., the reflux reaction is maintained, and the reaction time is 5-10 h.

[0038] Preferably, in S2, after the one-pot reaction is completed, the reaction product is cooled, the pH value of the reaction product is adjusted to 5-7 with an alkaline compound, and water is added to adjust the solid content to 20-40% to obtain the long-lasting, stable, collapse-resistant phosphate-based water reducer.

[0039] Preferably, the polyether macromonomer D is obtained by using a benzene derivative containing active hydrogen as an initiator to initiate the ring-opening polymerization of alkylene oxide.

[0040] Furthermore, the alkylene oxide is selected from one or more of ethylene oxide, propylene oxide, 1-butylene oxide, 2,3-butylene oxide, 2-methyl-1,2-propylene oxide, and 1-pentene oxide.

[0041] Furthermore, the alkylene oxide is a mixture of ethylene oxide and propylene oxide, and the molar percentage of ethylene oxide in the mixture is not less than 70%.

[0042] Preferably, the polyether macromonomer D is a polyether chain with a block structure or a random structure.

[0043] Furthermore, the polyether macromonomer D has a block structure.

[0044] The long-lasting, stable, collapse-resistant phosphate-based water reducer prepared by the above method.

[0045] Preferably, the weight average molecular weight of the water reducer is 4000~15000.

[0046] Beneficial effects: The preparation method of the present invention is simple, easy to operate, and is conducive to industrial implementation. In the present invention, an amino-containing monomer C is obtained by a ring-opening reaction between a monomer A and a polyamine monomer B. The amino-containing monomer C is a small molecule compound containing a primary amine, a secondary amine, and a phenoxy structure. After a one-pot process, the small molecule compound is subjected to a condensation reaction with a polyether macromonomer D and a small monomer E to form a product containing the structural effect of a polyetheramine, thereby avoiding the direct use of a relatively expensive polyetheramine. Therefore, an amino-containing polyether is prepared in the synthesis process of the present invention, and expensive amino-terminated polyether is not required, thereby greatly reducing the synthesis cost. The present invention avoids the use of a traditional method of first synthesizing a chlorinated polyether and then performing amination, thereby avoiding the introduction of chloride ions. DETAILED DESCRIPTION

[0047] The present invention is described in detail below by way of examples. These examples are merely illustrative and are not intended to limit the scope of the present invention. Based on the disclosure herein, those skilled in the art will be able to modify the reagents, catalysts, and reaction conditions within the scope of the present invention. Any equivalent changes or modifications made in accordance with the spirit of the present invention are intended to be encompassed within the scope of the present invention.

[0048] In the examples of the present invention, the molecular weight of the polymer was determined using gel permeation chromatography (gel column: Shodex SB806 + 803 columns in series; eluent: 0.1 M NaNO3 solution; mobile phase flow rate: 0.8 ml / min; injection: 20 μl of 0.5% aqueous solution; detector: Shodex RI-71 differential refractive index detector; standard: polyethylene glycol gel permeation chromatography standards (Sigma-Aldrich, molecular weights: 1,010,000, 478,000, 263,000, 118,000, 44,700, 18,600, 6,690, 1,960, 628, 232).

[0049] The parts mentioned in the examples are specifically parts by mass, and the amounts of other materials added are all converted to parts by mass. The aldehyde monomer G is 37 wt% formaldehyde.

[0050] The preparation of polyether macromonomer D is illustrated here using D-1 as an example. D-1 has a weight-average molecular weight of 2000 and is prepared using phenol as the initiator. The preparation method is ethoxylation: 94 parts phenol and 3 parts sodium hydroxide are weighed and added to a reactor. The reactor is evacuated to -0.1 MPa at room temperature. The reactor is then heated to 100°C and 30 parts ethylene oxide is slowly introduced. Once the pressure in the reactor decreases and the temperature rises, the reaction begins. 1876 parts ethylene oxide is then introduced, maintaining the reactor temperature between 100°C and 120°C and the pressure between 0.05 and 0.4 MPa. After the ethylene oxide addition is complete, the reactor is kept warm for approximately 1 hour. When the pressure in the reactor no longer decreases, the reactor is cooled and the material is discharged, yielding a light brown liquid. Gel permeation chromatography revealed a molecular weight of 1979 and a molecular weight distribution of 1.03.

[0051] Similarly, based on the above synthesis method, the following polyethers were prepared. EO represents ethylene oxide, PO represents propylene oxide, and EO / (EO+PO) refers to the molar ratio of ethylene oxide. The propylene oxide listed in the examples is located at the end of the polyether chain (i.e., away from the initiator structure).

[0052]

[0053] In the monomer A used, X is O, Y is methylene, and its numbering composition is as follows:

[0054]

[0055] In the small monomer E used, R3 is H, L is H, and its numbering composition is as follows:

[0056]

[0057] Example 1

[0058] Weigh 6.01 parts of ethylenediamine into a reaction flask. Heat to 115°C with stirring, then slowly add 15.02 parts of A-1 dropwise. Continue to react at this temperature for 3 hours. After the reaction is complete, remove the flask from the heat, add 80 parts of D-1 and 1.13 parts of the small monomer E-1. Then, add 10.22 parts of concentrated sulfuric acid, 24.60 parts of phosphorous acid, 38.52 parts of formaldehyde, and 0.33 parts of acetaldehyde (40 wt%) in that order. Heat to 140°C, and continue reflux for 5 hours. After the reaction is complete, cool and discharge to obtain a reddish-brown liquid. Adjust the pH to 5-7 with 32 wt% alkali solution and dilute with water to a solids content of 30-40%. Gel permeation chromatography revealed a molecular weight of 12416 with a molecular weight distribution of 1.43.

[0059] Example 2

[0060] Weigh 27.5 parts of polyethylene polyamine (CAS No. 68131-73-7) into a reaction flask. Heat to 80°C with stirring, then slowly add 22.53 parts of A-2 dropwise. Continue the reaction at this temperature for 1.5 hours. After the reaction is complete, remove the heat from the flask and add 600 parts of D-7 and 41.4 parts of the small monomer E-2. Then, add 131.37 parts of methanesulfonic acid, 54.12 parts of phosphorous acid, 121.34 parts of formaldehyde, and 2.70 parts of isobutyraldehyde in that order. Heat to 125°C and continue the reaction under reflux for 10 hours. After the reaction is complete, cool and discharge the mixture to obtain a reddish-brown liquid. Adjust the pH to 5-7 with 32 wt% alkali solution and dilute with water to a solids content of 30-40%. Gel permeation chromatography revealed a molecular weight of 4328 with a molecular weight distribution of 1.18.

[0061] Example 3

[0062] Weigh 11.62 parts of hexamethylenediamine into a reaction flask. Heat the flask to 110°C with stirring, then slowly add 16.52 parts of A-3 dropwise. Continue the reaction at this temperature for 3.5 hours. After the reaction is complete, remove the flask from the heat and add 33 parts of D-2 and 4.00 parts of the small monomer E-3. Then, add 11.73 parts of trifluoromethanesulfonic acid, 24.97 parts of phosphorous acid, 40.65 parts of formaldehyde, and 0.16 parts of valeraldehyde. Heat the flask to 100°C and continue the reaction under reflux for 6 hours. After the reaction is complete, cool the flask and discharge the mixture, yielding a reddish-brown liquid. Adjust the pH to 5-7 with 32 wt% alkali solution and dilute with water to a solids content of 30-40%. Gel permeation chromatography revealed a molecular weight of 6534 with a molecular weight distribution of 1.23.

[0063] Example 4

[0064] Weigh 10.81 parts of p-phenylenediamine into a reaction flask. Heat to 90°C with stirring, then slowly add 19.52 parts of A-4 dropwise. Continue the reaction at this temperature for 1 hour. After the reaction is complete, remove the heat from the reaction flask and add 195 parts of D-8 and 8.56 parts of the small monomer E-1. Then, add 32.75 parts of trifluoroethanesulfonic acid, 25.46 parts of phosphorous acid, 50.40 parts of formaldehyde, and 1.01 parts of methylglyoxal. Heat to 135°C and continue the reaction under reflux for 9.5 hours. After the reaction is complete, cool the mixture and discharge it, yielding a reddish-brown liquid. Adjust the pH to 5-7 with 32 wt% alkali solution and dilute with water to a solids content of 30-40%. Gel permeation chromatography revealed a molecular weight of 4551 with a molecular weight distribution of 1.19.

[0065] Example 5

[0066] Weigh 14.62 parts of triethylenetetramine into a reaction flask. Heat to 105°C with stirring, then slowly add 18.02 parts of A-5 dropwise. Continue to react at this temperature for 4.5 hours. After the reaction is complete, remove the heat from the reaction flask and add 40 parts of D-3 and 1.10 parts of the small monomer E-2. Then, add 14.75 parts of benzenesulfonic acid, 43.30 parts of phosphorous acid, 60.48 parts of formaldehyde, and 0.43 parts of 3-methylbutyraldehyde in that order. Heat to 110°C and continue reflux for 7 hours. After the reaction is complete, cool and discharge to obtain a reddish-brown liquid. Adjust the pH to 5-7 with 32 wt% alkali solution and dilute with water to a solids content of 30-40%. Gel permeation chromatography revealed a molecular weight of 14409 with a molecular weight distribution of 1.53.

[0067] Example 6

[0068] Weigh 23.24 parts of pentaethylenehexamine into a reaction flask. Heat to 100°C with stirring, then slowly add 15.02 parts of A-6 dropwise. Continue to react at this temperature for 2 hours. After the reaction is complete, remove the heat from the reaction flask and add 100 parts of D-6 and 9.71 parts of the small monomer E-3. Then, add 25.15 parts of p-toluenesulfonic acid, 57.40 parts of phosphorous acid, 78.40 parts of formaldehyde, and 0.26 parts of glycolaldehyde. Heat to 120°C and continue reflux for 8 hours. After the reaction is complete, cool and discharge to obtain a reddish-brown liquid. Adjust the pH to 5-7 with 32 wt% alkali solution and dilute with water to a solids content of 30-40%. Gel permeation chromatography revealed a molecular weight of 8689 with a molecular weight distribution of 1.37.

[0069] Example 7

[0070] Weigh 7.41 parts of propylene diamine and add it to a reaction flask. Heat the flask to 95°C with stirring, then slowly add 19.52 parts of A-1 dropwise. Continue the reaction at this temperature for 5 hours. After the reaction is complete, remove the flask from the heat and add 390 parts of D-4 and 6.11 parts of the small monomer E-1. Then, add 67.69 parts of concentrated sulfuric acid, 25.46 parts of phosphorous acid, 55.54 parts of formaldehyde, and 1.56 parts of phenylacetaldehyde in that order. Heat the flask to 130°C and continue the reaction under reflux for 5.5 hours. After the reaction is complete, cool the flask and discharge the mixture, yielding a reddish-brown liquid. Adjust the pH to 5-7 with 32 wt% alkali solution and dilute with water to a solids content of 30-40%. Gel permeation chromatography revealed a molecular weight of 7232 with a molecular weight distribution of 1.25.

[0071] Example 8

[0072] Weigh 10.22 parts of pentamethylenediamine into a reaction flask. Heat to 110°C with stirring, then slowly add 16.52 parts of A-2 dropwise. Continue to react at this temperature for 3 hours. After the reaction is complete, remove the heat from the reaction flask and add 137.5 parts of D-5 and 6.83 parts of the small monomer E-2. Then, add 18.82 parts of methanesulfonic acid, 23.78 parts of phosphorous acid, 45.04 parts of formaldehyde, and 0.34 parts of decanal in that order. Heat to 115°C and continue reflux for 7 hours. After the reaction is complete, cool and discharge to obtain a reddish-brown liquid. Adjust the pH to 5-7 with 32 wt% alkali solution and dilute with water to a solids content of 30-40%. Gel permeation chromatography revealed a molecular weight of 13361 with a molecular weight distribution of 1.49.

[0073] Example 9

[0074] Weigh 11.42 parts of cyclohexanediamine into a reaction flask. Heat the flask to 115°C with stirring, then slowly add 21.02 parts of A-3 dropwise. Continue the reaction at this temperature for 2.5 hours. After the reaction is complete, remove the flask from the heat and add 186.7 parts of D-1 and 10.19 parts of the small monomer E-3. Then, add 27.52 parts of trifluoromethanesulfonic acid, 25.58 parts of phosphorous acid, 44.59 parts of formaldehyde, and 1.07 parts of 3-hydroxypropanal. Heat the flask to 105°C and continue the reaction under reflux for 8.5 hours. After the reaction is complete, cool the flask and discharge the mixture, yielding a reddish-brown liquid. Adjust the pH to 5-7 with 32 wt% alkali solution and dilute with water to a solids content of 30-40%. Gel permeation chromatography revealed a molecular weight of 7610 with a molecular weight distribution of 1.26.

[0075] Example 10

[0076] Weigh 10.32 parts of diethylenetriamine into a reaction flask. Heat to 120°C with stirring, then slowly add 18.02 parts of A-4 dropwise. Continue the reaction at this temperature for 4 hours. After the reaction is complete, remove the heat from the reaction flask and add 48 parts of D-3 and 1.35 parts of the small monomer E-1. Then, add 11.65 parts of trifluoroethanesulfonic acid, 32.72 parts of phosphorous acid, 52.49 parts of formaldehyde, and 0.47 parts of 2-methylbutyraldehyde in that order. Heat to 120°C and continue the reaction under reflux for 7.5 hours. After the reaction is complete, cool the mixture and discharge it, yielding a reddish-brown liquid. Adjust the pH to 5-7 with 32 wt% alkali solution and dilute with water to a solids content of 30-40%. Gel permeation chromatography revealed a molecular weight of 9673 with a molecular weight distribution of 1.34.

[0077] Comparative Example 1

[0078] Weigh 18.93 parts of tetraethylenepentamine into a reaction flask. Heat to 105°C with stirring, then slowly add 22.53 parts of A-5 dropwise. Continue to react at this temperature for 2.5 hours. After the reaction is complete, remove the heat from the reaction flask and add 450 parts of D-6 and 0.83 parts of the small monomer E-2. Then, add 88.61 parts of benzenesulfonic acid, 49.61 parts of phosphorous acid, 85.73 parts of formaldehyde, and 0.53 parts of propionaldehyde. Heat to 125°C and continue reflux for 9 hours. After the reaction is complete, cool and discharge to obtain a reddish-brown liquid. Adjust the pH to 5-7 with 32 wt% alkali solution and dilute with water to a solids content of 30-40%. Gel permeation chromatography revealed a molecular weight of 4197 with a molecular weight distribution of 1.17.

[0079] Comparative Example 2

[0080] Weigh 8.82 parts of diaminobutane and add them to a reaction flask. Heat the flask to 85°C with stirring, then slowly add 16.52 parts of A-6 dropwise. Continue the reaction at this temperature for 5 hours. After the reaction is complete, remove the flask from the heat and add 165 parts of D-4 and 5.01 parts of the small monomer E-3. Then, add 25.39 parts of p-toluenesulfonic acid, 23.78 parts of phosphorous acid, and 46.99 parts of formaldehyde. Heat the flask to 130°C and continue the reflux reaction for 6.5 hours. After the reaction is complete, cool the flask and discharge the mixture, yielding a reddish-brown liquid. Adjust the pH to 5-7 with 32 wt% alkali solution and dilute with water to a solids content of 30-40%. Gel permeation chromatography revealed a molecular weight of 20,743 with a molecular weight distribution of 1.88.

[0081] Comparative Example 3

[0082] The commercially available high-performance collapse-retaining polycarboxylic acid admixture was purchased from Sika Company of Switzerland.

[0083] Application Examples

[0084] The performance of the phosphate-based water-reducing agent of the present invention was evaluated by concrete testing. In the application examples, the materials used in each cubic meter of concrete contained 490 kg of benchmark cement (PO 42.5); 60 kg of Huainan Pearl Grade I fly ash; 666 kg of granite crushed stone (5-10 mm); 444 kg of granite crushed stone (10-20 mm); 744 kg of machine-made sand (fineness modulus 2.6); and 132 kg of water.

[0085] Table 1 Concrete slump test results over time:

[0086]

[0087] The results in Table 1 show that the concrete slump of each embodiment of the present invention was maintained stable within 180 minutes, demonstrating the characteristic of long-term, stable slump retention. In contrast, the polycarboxylate slump retainer used in Comparative Example 3 had an initial slump of 16.7 cm, increased to a maximum of 21.2 cm, and then decreased to only 10.8 cm after 180 minutes, which could easily lead to concrete exudation and segregation, making construction unfavorable.

[0088] In summary, the phosphate-based water reducer of the present invention has the performance of long-term stable collapse prevention.

Claims

1. A method for preparing a long-lasting, stable, and slump-resistant phosphoric acid-based water reducer, characterized in that: The steps are as follows: S1. performing a ring-opening reaction between monomer A and polyamine monomer B to obtain an amino group-containing monomer C; S2. The amino-containing monomer C, polyether macromonomer D, small monomer E, catalyst F, phosphorous acid, aldehyde monomer G and aldehyde monomer J were reacted in one pot to obtain the long-lasting stable slump-proof phosphate-based water reducer; Wherein, the structure of the monomer A is as follows: ， Where R1 is H, C1~C10 alkyl, NR 1 , OR 2 or O(CH2) s OR 3 , R 1 、R 2 、R 3 is a C1-C5 alkyl group, s is an integer from 1 to 8, R1 is at any position of the ortho-ortho pair, and the number is 1 to 3; X is O or O(CH2) f O, f is an integer of 1 to 8; Y is a C1 to C5 alkyl group; The structure of the polyether macromonomer D is shown below: ， Where Z is O or O(CH2) g O, g is an integer of 1 to 8; Q is a C2 to C6 alkylene group, n = 10 to 70; R2 is H or a C1 to C10 alkyl group, R2 is in any position of the ortho-ortho pair, and the number is 1 to 3; The structure of the small monomer E is shown below: ， Wherein R3 is H or C1~C10 alkyl, R3 is in any position of the ortho-ortho pair, and the number is 1~3; K is O or O[(CH2) p O] r , p is an integer of 1 to 8, r is an integer of 1 to 8; L is H or a C1 to C5 alkyl group; The aldehyde monomer G is 37 wt% of formaldehyde; Taking the molar weight of the monomer A as q, the molar weight of the polyether macromonomer D as j, the molar weight of the small monomer E as t, and the molar weight of the unreacted amino hydrogen of the polyamine monomer B in S1 as k, then q:j=(0.5~3):1, t=(0.2~1.0)j, the molar weight of phosphorous acid is (1~1.2)k, the molar weight of the aldehyde monomer G is 1~1.2 times (q+j+t+k), and the molar weight of the aldehyde monomer J is 0.01~0.05 times (q+j+t).

2. The method for preparing a long-lasting, stable, collapse-resistant phosphoric acid-based water reducer according to claim 1, wherein: The polyamine monomer B is ethylenediamine, propylenediamine, butylenediamine, pentanediamine, hexanediamine, cyclohexanediamine, p-phenylenediamine, diethylenetriamine, triethylenetetramine, tetraethylenepentamine, pentaethylenehexamine or polyethylene polyamine; the aldehyde monomer J is acetaldehyde, propionaldehyde, isobutyraldehyde, butyraldehyde, valeraldehyde, heptanal, methylglyoxal, crotonaldehyde, 3-methylbutyraldehyde, hexanal, ethanolaldehyde, benzaldehyde, phenylacetaldehyde, octanal, decanal, cyclohexylcarboxaldehyde, 3-hydroxypropionaldehyde, 3-hydroxybutyraldehyde or 2-methylbutyraldehyde.

3. The method for preparing a long-lasting, stable, collapse-resistant phosphoric acid-based water reducer according to claim 1, characterized in that: The molar ratio of the monomer A to the polyamine monomer B is (1-1.5):

1.

4. The method for preparing a long-lasting, stable, collapse-resistant phosphoric acid-based water reducer according to claim 1, wherein: R1 is H or C1~C5 alkyl or OR 2 , R 2 is a C1~C5 alkyl group, X is O, and Y is a methylene group.

5. The method for preparing a long-lasting, stable, collapse-resistant phosphate-based water reducer according to claim 1, characterized in that: In the step S1, the reaction temperature is 80-120° C., and the reaction time is 1-5 h.

6. The method for preparing a long-lasting, stable, collapse-resistant phosphoric acid-based water reducer according to claim 1, characterized in that: R2 is H, Z is O, and QO is a mixture of ethylene oxide and propylene oxide, or ethylene oxide, wherein the molar percentage of ethylene oxide in the mixture is not less than 70%.

7. The method for preparing a long-lasting, stable, collapse-resistant phosphate-based water reducer according to claim 1, characterized in that: R3 is H, K is O or O[(CH2) p O] r , p is 2, r is 1 or 2, and L is H.

8. The method for preparing a long-lasting, stable, collapse-resistant phosphoric acid-based water reducer according to claim 1, characterized in that: The catalyst F is concentrated sulfuric acid, methanesulfonic acid, trifluoromethanesulfonic acid, trifluoroethanesulfonic acid, benzenesulfonic acid or p-toluenesulfonic acid; the amount of catalyst F is 10-20% of the total mass of the reactants in S2.

9. The method for preparing a long-lasting, stable, collapse-resistant phosphoric acid-based water reducer according to claim 1, characterized in that: In the step S2, the reaction temperature is 100-140° C., the reflux reaction is maintained, and the reaction time is 5-10 h.

10. The method for preparing a long-lasting, stable, collapse-resistant phosphoric acid-based water reducer according to claim 1, characterized in that: In S2, after the one-pot reaction is completed, the reaction product is cooled, the pH value of the reaction product is adjusted to 5-7 with an alkaline compound, and water is added to adjust the solid content to 20-40% to obtain the long-lasting, stable, collapse-resistant phosphate-based water reducer.

11. The method for preparing a long-lasting, stable, collapse-resistant phosphoric acid-based water reducer according to claim 1, characterized in that: The polyether macromonomer D is a polyether chain with a block structure or a random structure.

12. The method for preparing a long-lasting, stable, collapse-resistant phosphoric acid-based water reducer according to claim 1, characterized in that: The polyether macromonomer D is obtained by using a benzene derivative containing active hydrogen as an initiator to initiate the ring-opening polymerization of an alkylene oxide; the alkylene oxide is selected from one or more of ethylene oxide, propylene oxide, 1-butylene oxide, 2,3-butylene oxide, 2-methyl-1,2-propylene oxide, and 1-pentene oxide.

13. A long-acting, stable, collapse-retaining phosphate-based water reducer prepared by the method according to any one of claims 1 to 12.

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