Preparation method of polyether intermediate containing aldehyde group and amine group and application in phosphoric acid-based water reducer

Abstract

The present invention discloses a method for preparing a polyether intermediate containing an aldehyde group and an amine group and its application in a phosphoric acid-based water reducer. The method for preparing the intermediate containing an aldehyde group and an amine group is obtained by a Michael addition reaction between a polyamine monomer and an unsaturated aldehyde monomer, wherein the molar ratio of the polyamine monomer to the unsaturated aldehyde monomer is 1:1.5-2. The intermediate containing an aldehyde group and an amine group undergoes a substitution reaction with a chlorinated polyether to obtain a polyether macromonomer containing an aldehyde group and an amine group; the polyether macromonomer containing an aldehyde group and an amine group is used to prepare a phosphoric acid-based water reducer. The method for preparing the phosphoric acid-based water reducer utilizes the multifunctional properties of unsaturated aldehyde monomers to form a basic reticular skeleton with amino polyethers, so that the phosphoric acid-based water reducer is a bulk polymerized water reducer. In addition to having excellent water-reducing performance, the water reducer has better slump retention, slow setting and clay tolerance performance.

Description

Technical Field

[0001] The invention belongs to the field of concrete admixture preparation, and particularly relates to an aldehyde- and amine-containing polyether intermediate, a preparation method thereof, and application of the polyether intermediate in a phosphate-based water reducer. Background Art

[0002] Water reducer is an important component of modern concrete. It can regulate the rheological properties of concrete, improve mechanical properties and enhance durability, etc., providing the premise and guarantee for the development of concrete towards high performance.

[0003] In recent years, polycarboxylate water reducers have become the mainstream of industry research due to their advantages such as low dosage, high water reduction rate, and good cement adaptability. However, with the rapid development of China's economy, various targeted demands have emerged in the construction industry, and more new requirements have been put forward for cement water reducer technology. Theoretical research and engineering applications have shown that polycarboxylate water reducers have compatibility issues with concrete materials, such as rapid loss of concrete slump, abnormal coagulation, increased shrinkage, and easy cracking. In the face of such diverse demands, polycarboxylate water reducers have gradually become difficult to meet.

[0004] In order to solve the urgent problems facing the water reducer industry, engineers and researchers have introduced highly adsorbable phosphate groups from the level of water reducer molecular construction based on the above research theory. On the one hand, the added phosphate group has a stronger charge attraction than the carboxyl group; on the other hand, the added phosphate group can increase the water reducer's tolerance to calcium ions in the cement slurry system. At present, there are many patents and documents that disclose the preparation method of phosphate-based water reducers and the effects achieved.

[0005] Patent document CN102439063B discloses a low molecular weight phosphoric acid water reducer. The water reducer exhibits a certain retarding effect, and the retarding effect is prolonged with the increase of the dosage. The preparation cost of this type of water reducer is high and its application is difficult.

[0006] Patent document CN103342500A reports a clay shielding agent compounded from raw materials such as phosphates. The water reducer can be preferentially adsorbed onto the surface of clay particles in sand and gravel aggregates, thereby ensuring the effect of the polycarboxylic acid water reducer.

[0007] Patent document CN103596993A discloses a copolymer having geminal bisphosphate groups, which is less clay-sensitive than polycarboxylate water-reducing agents.

[0008] Patent document CN105504297A reports a phosphite concrete superplasticizer with a polyethyleneimine structure. Such polyether derivatives can be used alone or in combination with sulfonate-based water reducers, polycarboxylic acid water reducers, etc., and can effectively improve the flowability and collapse resistance of concrete.

[0009] The above patent articles and other articles disclose different types of phosphate-based water reducers, which show obvious collapse protection, slow setting, water reduction and certain anti-clay ability without losing other properties such as concrete strength. The performance of phosphate-based water reducers has gradually attracted the attention and recognition of industry practitioners, but compared with polycarboxylate water reducers, the research on phosphate-based water reducers is still in its infancy, and there is still room for breakthroughs in structure and design. Summary of the invention

[0010] The invention provides a method for preparing a polyether intermediate containing an aldehyde group and an amine group and application of the polyether intermediate in a phosphoric acid-based water reducer.

[0011] The preparation method of the intermediate containing aldehyde group and amine group is to obtain the intermediate by Michael addition reaction of polyamine monomer and unsaturated aldehyde monomer, wherein the molar ratio of the polyamine monomer to the unsaturated aldehyde monomer is 1: 1.5-2;

[0012] The polyamine monomer is selected from any one of ethylenediamine, propylenediamine, butylenediamine, pentylenediamine, hexylenediamine, cyclohexylenediamine, p-phenylenediamine, diethylenetriamine, triethylenetetramine, tetraethylenepentamine, pentaethylenehexamine and the like;

[0013] The structure of the unsaturated aldehyde monomer is shown in the following formula II:

[0014]

[0015] In the formula, R1, R2 and R3 each represent a hydrogen atom or a methyl group, and may be the same or different.

[0016] Preferably, the unsaturated aldehyde monomer is any one of acrolein, methacrolein, 2-butenal, 3-methyl-2-butenal, 2-methyl-2-butenal, and 2,3-dimethyl-2-butenal.

[0017] The unsaturated aldehyde monomer is more preferably acrolein, methacrolein, or 2-butenal.

[0018] The preparation method of the intermediate containing aldehyde groups and amine groups comprises the following steps: inducing a Michael addition reaction between a polyamine monomer and an unsaturated aldehyde monomer under the action of a catalyst, and after the reaction is completed, decompressing and vacuuming to remove excess unsaturated aldehyde monomers, and filtering to remove insoluble substances to obtain the intermediate containing aldehyde groups and amine groups.

[0019] The catalyst is a strong acidic cationic resin, such as NKC-9, Amberlyst-15, etc., which can be regenerated and reused repeatedly, and has a high catalytic efficiency. The amount of the catalyst is 1% to 1.5% of the mass of the polyamine monomer.

[0020] The Michael addition reaction between the polyamine monomer and the unsaturated aldehyde monomer induced by the catalyst is a solvent-free reaction, the temperature is 40 to 80° C., and the reaction pressure is the pressure of the reaction system itself;

[0021] The reaction time of the Michael addition reaction between the polyamine monomer and the unsaturated aldehyde monomer induced by the catalyst is 1 to 6 hours.

[0022] The intermediate containing aldehyde groups and amine groups undergoes a substitution reaction with chlorinated polyether to obtain a polyether macromonomer containing aldehyde groups and amine groups; the molar ratio of the chlorinated polyether to the intermediate containing aldehyde groups and amine groups is (0.6-1):1.

[0023] The polyether chain of the chlorinated polyether is obtained from ethylene oxide and / or ethylene oxide ring-opening reaction, and the weight average molecular weight of the polyether chain is between 600 and 3000.

[0024] The substitution reaction is a common reaction in organic chemistry and is well known to practitioners in the industry. The method reported in the reference document (patent CN 105504297 A) of the present invention uses water as the reaction medium, and the amount of water added is 30-60% of the mass of the chloropolyether.

[0025] The preparation method of the chlorinated polyether is well known to professionals in the field. The reference document reported in the present invention (He Weidong, Synthesis and Evaluation of Polyether Sulfonates [D], 2011, China University of Petroleum) is that the chlorinated polyether with a chlorinated structure is obtained by reacting a monoalkoxy polyether with chlorinated sulfoxide (SOCl2).

[0026] The substitution reaction has a reaction temperature of 100 to 140° C., a reaction time of 8 to 15 hours, and a reaction pressure of the system itself.

[0027] The polyether macromonomer containing aldehyde groups and amine groups is used for preparing a phosphoric acid-based water reducer.

[0028] The phosphoric acid-based water reducer is obtained by the Mannich reaction of the polyether macromonomer containing aldehyde groups and amine groups with phosphorous acid and aldehyde monomers under the action of a phosphorylation catalyst, followed by neutralization.

[0029] The phosphorylation catalyst is a strong acid catalyst, and the catalyst is one or a mixture of concentrated hydrochloric acid, concentrated sulfuric acid, methanesulfonic acid, trifluoromethanesulfonic acid, benzenesulfonic acid, p-toluenesulfonic acid, etc.;

[0030] The amount of the catalyst used is generally equal to the mass of the polyamine monomer in the synthesis process of the intermediate containing aldehyde groups and amine groups.

[0031] The aldehyde monomer is any one of formaldehyde, trioxymethylene or polyoxymethylene. Considering the cost and the convenience of reaction operation, 37 wt % of formaldehyde is preferably used as the aldehyde monomer used in the present invention.

[0032] In the Mannich reaction, the molar ratio of the number of nitrogen atoms in the polyamine, phosphorous acid, and aldehyde monomer is n: (1~1.1)[n*x+(n+1)*(1-x)]:(1~1.2)[(n-1)*x+n*(1-x)], wherein x is the molar ratio of the amount of chlorinated polyether added to the polyamine. Simplified, the ratio of the three can be obtained as n:(1~1.1)(n+1-x):(1~1.2)(nx).

[0033] The Mannich reaction is carried out by first slowly adding the catalyst, then adding the phosphorous acid, and finally adding the aldehyde monomer to the reaction system in a dropwise manner under the conditions of water bath cooling at room temperature and mechanical stirring.

[0034] In the Mannich reaction, the reaction system is heated to 100-140° C. and the reaction time is maintained at 6-12 hours to obtain the phosphate-based water reducer product.

[0035] The neutralization refers to neutralizing the reaction system to about pH=7, and then adding water to dilute it to a certain concentration. Generally, water is added to dilute the water reducer to about 30% to 40% for the purpose of storage and transportation.

[0036] The preparation method of the phosphate-based water reducer of the present invention utilizes the multifunctional properties of unsaturated aldehyde monomers to form a basic network skeleton with amino polyether (containing polyamines), so that the phosphate-based water reducer is a bulk polymeric water reducer. In addition to having excellent water-reducing performance, the water reducer has better slump retention, slow setting and clay tolerance performance, and the specific advantages are as follows:

[0037] The introduction of phosphorous acid adsorption groups breaks through the traditional carboxyl and sulfonic acid systems, has strong adsorption capacity, and exhibits strong anti-clay performance. This feature has great performance advantages in today's market environment where concrete admixtures and aggregates are of poor quality. The phosphorous acid structure can provide excellent water reduction while improving the collapse protection and slow setting effects; and the entire preparation process of the method of the present invention is simple to operate, with low raw material cost and low production energy consumption, and the preparation process has the prospect of industrialization. DETAILED DESCRIPTION

[0038] The present invention is described in detail below by examples, which are merely illustrative and do not limit the scope of application of the present invention. According to the disclosure herein, those skilled in the art can change the reagents, catalysts and reaction process conditions within the scope of the present invention. Any equivalent changes or modifications made according to the spirit of the present invention should be included in the protection scope of the present invention.

[0039] Molecular weight test conditions: The molecular weight of all condensation polymers in the examples of the present invention was measured using aqueous gel permeation chromatography (GPC), and the experimental conditions were as follows:

[0040] Gel column: Shodex SB806+803 two chromatographic columns connected in series;

[0041] Mobile phase: 0.1M NaNO3 aqueous solution;

[0042] Mobile phase speed: 1.01 ml / min;

[0043] Injection: 20 μl 0.5% aqueous solution;

[0044] Detector: Shodex RI-71 differential refractometer;

[0045] Standard: polyethylene glycol GPC standards (Sigma-Aldrich, molecular weight 1010000, 478000, 263000, 118000, 44700, 18600, 6690, 1960, 628, 232).

[0046] In the application examples of the present invention, unless otherwise specified, the cement used is the reference cement (P.042.5), the sand is the medium sand with a fineness modulus Mx=2.6, and the gravel is the crushed stone with a particle size of 5 to 20 mm and continuous grading. The cement paste fluidity test is carried out in accordance with the GB / T8077-2000 standard, with a water addition amount of 87g. The cement paste fluidity is measured on a flat glass after stirring for 4 minutes. The air content and water reduction rate test methods are carried out in accordance with the relevant provisions of GB8076-2008 "Concrete Admixtures".

[0047] The parts described in the examples are specifically parts by mass, and the amounts of other materials added are all converted into parts by mass.

[0048] Example 1

[0049] 88.15 parts of diaminobutane, 89.70 parts of acrolein and 1.06 parts of NKC-9 were placed in a reaction bottle, heated to 55°C, stirred and reacted for 3.5 hours. After the reaction was completed, the excess acrolein was evaporated under reduced pressure and vacuum, and the insoluble matter was filtered out to obtain an intermediate containing aldehyde and amine groups; under stirring, 360 parts of water and 900 parts of chloropolyether (Mn=1500) were continuously added to the above reaction bottle, heated to 110°C, and reacted for 10 hours; after the reaction was completed, the temperature was lowered to below 80°C, and 238.24 parts of concentrated hydrochloric acid and 202.70 parts of phosphorous acid were continuously slowly added under stirring. 120.44 parts of 37% formaldehyde solution were added, the temperature was raised to 140°C, and the reaction was carried out for 12 hours. After the reaction, a 32.5% NaOH solution was used to neutralize the mixture to a pH of about 7, and water was added to dilute the mixture to 30% to obtain a brown water reducing agent product. The molecular weight was 25661 and the molecular weight distribution was 1.55 after GPC testing.

[0050] Example 2

[0051] 114.19 parts of cyclohexanediamine, 126.16 parts of methacrolein and 1.26 parts of Amberlyst-15 were placed in a reaction bottle, heated to 80°C, and stirred for reaction for 5 hours. After the reaction was completed, the excess methacrolein was evaporated under reduced pressure and vacuum, and the insoluble matter was filtered out to obtain an intermediate containing aldehyde and amine groups. Under stirring, 1031 parts of water and 1875 parts of chloropolyether (Mn=2500) were added to the above reaction bottle, heated to 130°C, and reacted for 14.5 hours. h; after the reaction, cool to below 80°C, continue to slowly add 114.19 parts of concentrated sulfuric acid, 195.57 parts of phosphorous acid, and 116.67 parts of 37% formaldehyde solution under stirring, heat to 125°C, react for 6h, after the reaction, use 32.5% NaOH solution to neutralize to about PH=7, add water to dilute to 30%, and obtain a brown water reducer product. The molecular weight was 19771 and the molecular weight distribution was 1.61 after GPC test.

[0052] Example 3

[0053] 103.17 parts of diethylenetriamine, 133.17 parts of 2-butenal and 1.03 parts of NKC-9 were placed in a reaction bottle, heated to 40°C, stirred and reacted for 4.5 hours, and after the reaction was completed, the excess 2-butenal was evaporated under reduced pressure and vacuum, and the insoluble matter was filtered out to obtain an intermediate containing aldehyde and amine groups; under stirring, 162 parts of water and 540 parts of chloropolyether (Mn=600) were added to the above reaction bottle, heated to 105°C, and reacted for 8.5 hours; the reaction result was as follows: After the reaction was completed, the temperature was lowered to below 80°C, and 103.17 parts of methanesulfonic acid, 259.28 parts of phosphorous acid, and 175.55 parts of 37% formaldehyde solution were slowly added under stirring. The temperature was raised to 100°C and the reaction was carried out for 9.5 hours. After the reaction was completed, a 32.5% NaOH solution was used to neutralize the mixture to a pH of about 7, and the mixture was diluted with water to 30% to obtain a brown water reducing agent product. The molecular weight was 11450 and the molecular weight distribution was 1.22 as tested by GPC.

[0054] Example 4

[0055] 189.30 parts of tetraethylenepentamine, 95.30 parts of acrolein and 2.46 parts of Amberlyst-15 were placed in a reaction bottle, heated to 65°C, stirred and reacted for 6 hours, and after the reaction was completed, the excess acrolein was evaporated under reduced pressure and vacuum, and the insoluble matter was filtered out to obtain an intermediate containing aldehyde and amine groups; under stirring, 900 parts of water and 2000 parts of chloropolyether (Mn=2000) were added to the above reaction bottle, heated to 140°C, and reacted for 14 hours; the reaction result was as follows: After the reaction was completed, the temperature was lowered to below 80°C, and 189.30 parts of trifluoromethanesulfonic acid, 430.50 parts of phosphorous acid, and 353.87 parts of 37% formaldehyde solution were slowly added under stirring. The temperature was raised to 135°C and the reaction was carried out for 6.5 hours. After the reaction was completed, a 32.5% NaOH solution was used to neutralize the mixture to a pH of about 7, and the mixture was diluted with water to 30% to obtain a brown water reducing agent product. The molecular weight was 19428 and the molecular weight distribution was 1.38 as tested by GPC.

[0056] Example 5

[0057] 60.10 parts of ethylenediamine, 105.14 parts of methacrolein and 0.90 parts of NKC-9 were placed in a reaction bottle, heated to 70°C, stirred and reacted for 1.5 hours, and after the reaction was completed, the excess methacrolein was evaporated under reduced pressure and vacuum, and the insoluble matter was filtered out to obtain an intermediate containing aldehyde and amine groups; under stirring, 975 parts of water and 1950 parts of chloropolyether (Mn=3000) were added to the above reaction bottle, heated to 105°C, and reacted for 9 hours; the reaction result was as follows: After the reaction was completed, the temperature was lowered to below 80°C, and 60.10 parts of benzenesulfonic acid, 192.70 parts of phosphorous acid, and 109.57 parts of 37% formaldehyde solution were slowly added under stirring. The temperature was raised to 120°C and the reaction was carried out for 10 hours. After the reaction was completed, a 32.5% NaOH solution was used to neutralize the mixture to a pH of about 7, and the mixture was diluted with water to 30% to obtain a brown water reducing agent product. The molecular weight was 35591 and the molecular weight distribution was 1.64 as tested by GPC.

[0058] Example 6

[0059] 232.37 parts of pentaethylenehexamine, 140.18 parts of 2-butenal and 2.79 parts of Amberlyst-15 were placed in a reaction bottle, heated to 60°C, stirred and reacted for 3 hours, and after the reaction was completed, the excess 2-butenal was removed by vacuum distillation under reduced pressure. Crotonaldehyde, filter out insoluble matter to obtain an intermediate containing aldehyde and amine groups; under stirring, continue to add 350 parts of water and 1000 parts of chloropolyether (Mn=1000) to the above reaction bottle, heat to 125°C, and react for 13.5h; after the reaction, cool to below 80°C, continue to slowly add 232.27 parts of p-toluenesulfonic acid, 511.68 parts of phosphorous acid, and 482.91 parts of 37% formaldehyde solution under stirring, heat to 105°C, and react for 7h. After the reaction, use a 32.5% NaOH solution to neutralize to about PH=7, add water to dilute to 30%, and obtain a brown water reducer finished product. The GPC test showed that the molecular weight was 12640 and the molecular weight distribution was 1.29.

[0060] Example 7

[0061] 74.12 parts of propylene diamine, 84.09 parts of acrolein and 1.04 parts of NKC-9 were placed in a reaction bottle, heated to 45°C, stirred and reacted for 2.5 hours, and after the reaction was completed, the excess acrolein was distilled off under reduced pressure and vacuum, and the insoluble matter was filtered out to obtain an intermediate containing aldehyde and amine groups; under stirring, 144 parts of water and 480 parts of chloropolyether (Mn=600) were continuously added to the above reaction bottle, heated to 130°C, and reacted for 10.5 hours; after the reaction was completed, the temperature was lowered to below 80°C, and 200.32 parts of concentrated hydrochloric acid and 193.03 parts of phosphorous acid were continuously slowly added under stirring. 105.19 parts of 37% formaldehyde solution were heated to 115°C and reacted for 10.5 hours. After the reaction, a 32.5% NaOH solution was used to neutralize the mixture to a pH of about 7, and the mixture was diluted with water to 30% to obtain a brown water reducing agent product. The GPC test showed that the molecular weight was 10333 and the molecular weight distribution was 1.19.

[0062] Example 8

[0063] 102.18 parts of pentamethylenediamine, 112.14 parts of methacrolein and 1.02 parts of Amberlyst-15 were placed in a reaction bottle, heated to 80°C, stirred and reacted for 1 hour, and after the reaction was completed, the excess methacrolein was evaporated under reduced pressure and vacuum, and the insoluble matter was filtered out to obtain an intermediate containing aldehyde and amine groups; under stirring, 1275 parts of water and 2125 parts of chloropolyether (Mn=2500) were continuously added to the above reaction bottle, heated to 100°C, and reacted for 8 hours; after the reaction was completed, the temperature was lowered to below 80°C, and 102.18 parts of concentrated sulfuric acid, 181.59 parts of phosphorous acid, and 104.54 parts of 37% formaldehyde solution were continuously slowly added under stirring, and the temperature was raised to 130°C, and the reaction was continued for 7.5 hours. h. After the reaction, a 32.5% NaOH solution was used to neutralize the mixture to a pH of about 7, and water was added to dilute the mixture to 30% to obtain a brown water reducing agent product. The GPC test showed that the molecular weight was 23606 and the molecular weight distribution was 1.52.

[0064] Example 9

[0065] 108.14 parts of p-phenylenediamine, 126.16 parts of 2-butenal and 1.30 parts of NKC-9 were placed in a reaction bottle, heated to 50°C, stirred and reacted for 5 hours, and after the reaction was completed, the excess 2-butenal was evaporated under reduced pressure and vacuum, and the insoluble matter was filtered out to obtain an intermediate containing aldehyde and amine groups; under stirring, 420 parts of water and 1050 parts of chloropolyether (Mn=1500) were added to the above reaction bottle, heated to 135°C, and reacted for 12 hours; the reaction result was as follows: After the reaction was completed, the temperature was lowered to below 80°C, and 108.14 parts of methanesulfonic acid, 205.57 parts of phosphorous acid, and 109.73 parts of 37% formaldehyde solution were slowly added under stirring. The temperature was raised to 110°C and the reaction was carried out for 11 hours. After the reaction was completed, a 32.5% NaOH solution was used to neutralize the mixture to a pH of about 7, and the mixture was diluted with water to 30% to obtain a brown water reducing agent product. The molecular weight was 21838 and the molecular weight distribution was 1.56 as tested by GPC.

[0066] Example 10

[0067] 146.23 parts of triethylenetetramine, 106.51 parts of acrolein and 1.90 parts of Amberlyst-15 were placed in a reaction bottle, heated to 60°C, stirred and reacted for 2 hours, and after the reaction was completed, the excess acrolein was distilled off under reduced pressure and vacuum, and the insoluble matter was filtered out to obtain an intermediate containing aldehyde and amine groups; under stirring, 1568 parts of water and 2850 parts of chloropolyether (Mn=3000) were continuously added to the above reaction bottle, heated to 120°C, and reacted for 13 hours; after the reaction was completed, the temperature was lowered to below 80°C, and 146.23 parts of trifluoromethanesulfonic acid were continuously slowly added under stirring. 348.71 parts of phosphorous acid, 297.05 parts of 37% formaldehyde solution, heated to 125°C, reacted for 8 hours, after the reaction, neutralized with 32.5% NaOH solution to about PH=7, diluted with water to 30%, to obtain a brown water reducing agent product, tested by GPC, the molecular weight was 31100, and the molecular weight distribution was 1.68.

[0068] Comparative Example 1

[0069] 102.18 parts of pentamethylenediamine, 119.15 parts of methacrolein and 1.53 parts of NKC-9 were placed in a reaction bottle, heated to 75°C, and stirred for reaction for 5.5 hours. After the reaction was completed, the excess methacrolein was evaporated under reduced pressure and vacuum, and the insoluble matter was filtered out to obtain an intermediate containing aldehyde and amine groups. Under stirring, 1440 parts of water and 2400 parts of chloropolyether (Mn=4000) were added to the above reaction bottle, heated to 115°C, and reacted for 9.5 hours. h; after the reaction, cool to below 80°C, continue to slowly add 102.18 parts of benzenesulfonic acid, 216.48 parts of phosphorous acid, and 114.76 parts of 37% formaldehyde solution under stirring, heat to 140°C, react for 15h, and after the reaction, use 32.5% NaOH solution to neutralize to about PH=7, add water to dilute to 30%, and obtain a brown water reducer product. The molecular weight was 65592 and the molecular weight distribution was 1.93 after GPC test.

[0070] Comparative Example 2

[0071] 103.17 parts of diethylenetriamine, 126.16 parts of 2-butenal and 1.13 parts of Amberlyst-15 were placed in a reaction bottle, heated to 40°C, stirred and reacted for 4 hours, and after the reaction was completed, the excess 2-butenal was removed by vacuum distillation under reduced pressure. Crotonaldehyde, filter and remove insoluble matter to obtain an intermediate containing aldehyde and amine groups; under stirring, continue to add 855 parts of water and 1900 parts of chloropolyether (Mn=2000) to the above reaction bottle, heat to 130°C, and react for 6 hours; after the reaction, cool to below 80°C, continue to slowly add 103.17 parts of p-toluenesulfonic acid, 225.09 parts of phosphorous acid, and 196.33 parts of 37% formaldehyde solution under stirring, heat to 115°C, and react for 8.5 hours. After the reaction, use a 32.5% NaOH solution to neutralize to about PH=7, add water to dilute to 30%, and obtain a brown water reducer finished product. The GPC test showed that the molecular weight was 19874 and the molecular weight distribution was 1.65.

[0072] Comparative Example 3

[0073] 88.15 parts of diaminobutane and 1.06 parts of NKC-9 were placed in a reaction bottle, heated to 55°C, stirred for reaction for 3.5 hours, and after the reaction was completed, the insoluble matter was filtered out to obtain an intermediate; under stirring, 360 parts of water and 900 parts of chloropolyether (Mn=1500) were continuously added to the above reaction bottle, heated to 110°C, and reacted for 10 hours; after the reaction was completed, the temperature was lowered to below 80°C, and 238.24 parts of concentrated hydrochloric acid, 202.70 parts of phosphorous acid, and 120.44 parts of 37% formaldehyde solution were continuously slowly added under stirring, heated to 140°C, and reacted for 12 hours. After the reaction was completed, a NaOH solution with a mass concentration of 32.5% was used to neutralize to about PH=7, and water was added to dilute to 30% to obtain a brown water reducer finished product. The molecular weight was 1823 and the molecular weight distribution was 1.15 as tested by GPC.

[0074] Comparative Example 4

[0075] 89.70 parts of acrolein and 1.06 parts of NKC-9 were placed in a reaction bottle, heated to 55°C, stirred and reacted for 3.5 hours. After the reaction was completed, the excess acrolein was distilled off under reduced pressure and vacuum, and the insoluble matter was filtered out to obtain an intermediate; under stirring, 360 parts of water and 900 parts of chloropolyether (Mn=1500) were continuously added to the above reaction bottle, heated to 110°C, and reacted for 10 hours; after the reaction was completed, the temperature was lowered to below 80°C, and 238.24 parts of concentrated hydrochloric acid, 202.70 parts of phosphorous acid, and 120.44 parts of 37% formaldehyde solution were continuously slowly added under stirring, heated to 140°C, and reacted for 12 hours. After the reaction was completed, a NaOH solution with a mass concentration of 32.5% was used to neutralize to about PH=7, and water was added to dilute to 30% to obtain a brown water reducer finished product. The molecular weight was 1627 and the molecular weight distribution was 1.09 as tested by GPC.

[0076] Application Example 1

[0077] Cement paste fluidity test: refer to GB / T8077-2000, use 300g of standard cement and 87g of water. The detailed data are shown in Table 1.

[0078] Table 1 Test of fluidity of pure slurry

[0079]

[0080] It can be seen from Table 1 that the small molecule water reducing agent of the present invention not only has good dispersibility for cement, but also has good fluidity retention ability.

[0081] The molecular weight of the polyether in Comparative Example 1 is 4000, which is outside the range. Because the molecular weight of the polyether is large, the reaction is not sufficient, resulting in a rapid loss of fluidity of the net slurry; the reaction time of Comparative Example 2 is too short, which is 6 hours, and the proportion of phosphorous acid added is insufficient, resulting in a rapid loss of fluidity of the net slurry.

[0082] Comparative Examples 3 and 4 failed to successfully introduce the intermediate containing aldehyde and amine groups, and only added polyamine monomers or unsaturated aldehyde monomers as intermediates, which either made the concrete lack good fluidity retention ability or failed to function as a water reducer.

[0083] Application Example 2

[0084] Setting time, air content and slump test: The air content was measured with reference to the relevant test methods of GB8076-2008 "Concrete Admixtures"; the slump of the fresh concrete of the product of the present invention and the change of the slump over time at 60 min and 120 min were measured with reference to the relevant methods of JC473-2001 "Concrete Pumping Agents". The amount of water reducing agent was fixed at 0.18% of the amount of cement. The experimental results are shown in Table 2.

[0085] Table 2 Concrete test

[0086]

[0087] The above experiments show that the small molecule water reducer of the present invention can obtain excellent slump retention ability and good retarding effect at a relatively low dosage.

[0088] The molecular weight of the polyether in Comparative Example 1 is 4000, resulting in insufficient slump and expansion; the reaction time of Comparative Example 2 is too short, which is 6 hours, resulting in insufficient slump and expansion at 120 minutes.

[0089] Comparative Examples 3 and 4 failed to successfully introduce the intermediate containing aldehyde groups and amine groups, and only added polyamine monomers or unsaturated aldehyde monomers as intermediates, respectively, and the resulting concrete did not meet the requirements of slump and expansion.

[0090] Application Example 3

[0091] In order to evaluate the sensitivity of the collapse-preserving small molecule superplasticizer of the present invention to clay, the fluidity of the mortar prepared with sand containing clay was tested. The expansion test of the mortar was carried out with reference to GB / T17671-1999 "Method for Determination of Fluidity of Cement Mortar", wherein the cement used was the base cement, the mortar-sand ratio was 1:3; the clay replaced 0.5% of the mass of the sand; and the water-cement ratio was 0.44. The fluidity of the freshly mixed mortar of the product of the present invention and the change of the fluidity over time at 60min and 120min were measured.

[0092] Table 3 Mortar test

[0093]

[0094] The above experiments show that the small molecule water reducer of the present invention has a relatively low sensitivity to clay in sand at a lower dosage.

[0095] The molecular weight of the polyether in Comparative Example 1 is 4000; the reaction time of Comparative Example 2 is too short, which is 6 hours, resulting in a too fast loss of fluidity of the mortar.

[0096] Comparative Examples 3 and 4 failed to successfully introduce the intermediate containing aldehyde groups and amine groups, and only added polyamine monomers or unsaturated aldehyde monomers as intermediates, respectively, which made the obtained mortars fail to meet the fluidity requirements.

Claims

1. A method for preparing a phosphoric acid-based water reducer, characterized in that: The polyether macromonomer containing aldehyde groups and amine groups reacts with phosphorous acid and aldehyde monomers under the action of a phosphorylation catalyst to undergo a Mannich reaction, followed by neutralization to obtain the product. The phosphorylation catalyst is a strong acid catalyst, and the catalyst is one or a mixture of concentrated hydrochloric acid, concentrated sulfuric acid, methanesulfonic acid, trifluoromethanesulfonic acid, benzenesulfonic acid, p-toluenesulfonic acid, etc.; The amount of the catalyst used is equal to the mass of the polyamine monomer in the synthesis process of the intermediate containing aldehyde groups and amine groups; the aldehyde monomer is any one of formaldehyde, trioxymethylene or polyoxymethylene; In the Mannich reaction, the molar ratio of the number of nitrogen atoms in the polyamine, phosphorous acid, and aldehyde monomer is n: (1-1.1) (n+1-x): (1-1.2) (nx), where n is the number of nitrogen atoms in the polyamine; and x is the molar ratio of the amount of chlorinated polyether to the amount of polyamine added; The intermediate containing aldehyde groups and amine groups undergoes a substitution reaction with a chlorinated polyether to obtain the polyether macromonomer containing aldehyde groups and amine groups; the molar ratio of the chlorinated polyether to the intermediate containing aldehyde groups and amine groups is (0.6-1):1; The preparation method of the intermediate containing aldehyde groups and amine groups is to obtain the intermediate by Michael addition reaction of polyamine monomers and unsaturated aldehyde monomers, wherein the molar ratio of the polyamine monomers to the unsaturated aldehyde monomers is 1:1.5-2; The polyamine monomer is selected from any one of ethylenediamine, propylenediamine, butylenediamine, pentylenediamine, hexylenediamine, cyclohexylenediamine, p-phenylenediamine, diethylenetriamine, triethylenetetramine, tetraethylenepentamine, pentaethylenehexamine and the like; The structure of the unsaturated aldehyde monomer is shown in the following formula II: (Ⅱ) wherein R1, R2 and R3 each represent a hydrogen atom or a methyl group and may be the same or different; The polyether chain of the chlorinated polyether is obtained by ethylene oxide and / or ethylene oxide ring-opening reaction, and the weight average molecular weight of the polyether chain is between 600 and 3000; The preparation method of the intermediate containing aldehyde groups and amine groups comprises the following steps: inducing a Michael addition reaction between a polyamine monomer and an unsaturated aldehyde monomer under the action of a catalyst, and after the reaction is completed, decompressing and vacuuming to remove excess unsaturated aldehyde monomers, and filtering to remove insoluble substances to obtain the intermediate containing aldehyde groups and amine groups; The catalyst is a strong acidic cationic resin selected from NKC-9 or Amberlyst-15, and the amount of the catalyst is 1% to 1.5% of the mass of the polyamine monomer; The Michael addition reaction of the polyamine monomer and the unsaturated aldehyde monomer induced by the catalyst is a solvent-free reaction, the temperature is 40-80°C, and the reaction pressure is the pressure of the reaction system itself; the reaction time of the Michael addition reaction of the polyamine monomer and the unsaturated aldehyde monomer induced by the catalyst is 1-6 hours; The substitution reaction has a reaction temperature of 100-140° C., a reaction time of 8-15 hours, and a reaction pressure of the system itself.

2. The method according to claim 1, characterized in that: The unsaturated aldehyde monomer is any one of acrolein, methacrolein, 2-butenal, 3-methyl-2-butenal, 2-methyl-2-butenal, and 2,3-dimethyl-2-butenal.

3. The method according to claim 1, characterized in that: The Mannich reaction is carried out by first slowly adding the catalyst, then adding the phosphorous acid, and finally adding the aldehyde monomer to the reaction system in a dropwise manner under the conditions of water bath cooling at room temperature and mechanical stirring.

4. The method according to claim 1, characterized in that: In the Mannich reaction, the reaction system is heated to 100-140° C. and the reaction time is maintained for 6-12 h to obtain the phosphate-based water reducer.

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